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Bacteriological Profile and Antibiotic Sensitivity Patterns of Odontogenic Abscesses in Patients with a History of Empiric Antibiotic Therapy
Microbiology of Odontogenic Abscesses Asian J Oral Maxillofac Surg. 2006;18:272-9. CLINICAL OBSERVATIONS
Bacteriological Profile and Antibiotic Sensitivity Patterns of Odontogenic Abscesses in Patients with a History of Empiric Antibiotic Therapy Amol S Kulkarni, Vinod Narayanan Department of Oral and Maxillofacial Surgery, College of Dental Surgery, Saveetha Institute of Medical and Technical Sciences, Chennai, Tamil Nadu, India
Abstract Objective: To determine the microbiology of odontogenic abscesses in patients with a history of empiric antibiotic administration. Patients and Methods: Percutaneous or permucosal aspiration of pus was carried out from closed nondraining abscesses using strict disinfection techniques and processing in an aerobic and anaerobic environment. Antibiotic sensitivity testing was performed by the Kirby-Bauer method. Results: A total of 120 isolates were reported from 100 study samples. In all, 27 different strains of microorganisms were isolated from the study group, with an average of 2.7 isolates per sample. Viridans streptococci were the most frequently isolated organisms. Of 7 antibiotics tested, penicillin G, clindamycin and ciprofloxacin had excellent activity against the isolates. Conclusions: Orofacial odontogenic abscesses in patients with a history of empiric antibiotic therapy predominantly contain Gram-positive facultative organisms, especially viridans streptococci. The precise role of anaerobic organisms in persistent infections following empiric antibiotic therapy is debatable, and further investigations using molecular biological techniques are required. Penicillin G, as tested in this study, remains the drug of choice for treating odontogenic infections. The incidence of penicillin resistance was found to be negligible in this study. Key words: Bacteriology, Microbial sensitivity tests, Penicillin G, Viridans streptococci
Introduction Infection may be defined as the invasion and multiplication of micro organisms in body tissues resulting in local cellular injury due to competitive metabolism, toxin production, intracellular replication or antigenantibody reaction. Infections can be autogenous, i.e., caused by the host flora that becomes pathogenic for some reason, or may be due to cross-infection. In cases of odontogenic infection, the former is the commonest cause, but cross-infection may occur due to the use of non-sterile injections and contaminated needles.1
Vera in 2004 proposed a simple classification of oral infections into 2 large groups — odontogenic and non-odontogenic. 2 Odontogenic infections (caries, periodontitis, periapical abscess, periodontal abscess, pericoronitis, pulpitis, osteitis and infections of aponeurotic spaces) can be subdivided into primary (usually related to progression of caries) and secondary (secondary to traumatic injury, dental extraction or surgery) infections. Non-odontogenic infections include those affecting the mucosa, salivary glands and bones.
Correspondence: Prof Vinod Narayanan, Department of Oral and Maxillofacial Surgery, College of Dental Surgery, Saveetha Institute of Medical and Technical Sciences (Deemed University), 172 Poonamalle High Road, Chennai 600 077, Tamil Nadu, India. Tel: (91 44) 2626 0990; Fax: (91 44) 2680 0892; E-mail: [email protected]
Most oral infections are primarily odontogenic in nature.1 Orofacial abscesses of odontogenic origin are a common sequela of deeply carious or periodontally involved teeth or pericoronal infections. Most of these infections can be managed by tooth
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© 2006 AsianAsian Association J Oral of Maxillofac Oral and Surg Maxillofacial Vol 18, No Surgeons. 4, 2006
Kulkarni, Narayanan
extraction, endodontic treatment and/or surgical drainage without the use of antimicrobials.3-9 However, antimicrobials need to be prescribed in acute fascial space infections or in case of immunocompromised patients. The choice of antimicrobials is case-specific and based on factors including laboratory data, patient health, age, allergies, drug absorption, distribution ability and plasma levels. The cost of drugs, type and location of infection and previous antibiotic history also need to be considered.3,9-13 Although fatal infections of odontogenic origin are uncommon, infectious diseases remain the leading cause of death worldwide. Shifting infectious disease patterns and their manifestations have become a topic of discussion. It is debatable as to whether the infection patterns are actually changing14 and whether the characteristics of pathogenic bacteria causing odontogenic infections are today different from those reported in the literature. There has been a noticeable change in the pathogenic genera isolated from odontogenic abscesses over the past 2 to 3 decades. This may be attributable to the taxonomic changes in the microbiological world and perhaps the use of better diagnostic techniques.1,8,9,13,15-17 However, very few studies have specifically investigated the bacteriological profiles and sensitivity patterns in isolates from individuals with odontogenic abscesses and a history of incomplete antibiotic therapy, which is a commonly encountered situation in developing countries. The aim of this study was to determine the microbiology of odontogenic abscesses in patients with a history of empiric antibiotic therapy.
Patients and Methods This prospective study included patients reporting to the outpatient division of the Department of Oral and Maxillofacial Surgery between January and August 2005. Patients of all age groups with the complaint of face swellings were screened clinically and considered for the study. Detailed history and thorough clinical examinations were performed to determine the presence of an odontogenic abscess. Radiological examination of the area of chief complaint was done to confirm Asian J Oral Maxillofac Surg Vol 18, No 4, 2006
the causative tooth. Any known systemic disease condition was noted along with the medication for the condition. Antibiotic history was noted in detail. History of drug administration was verified on reviewing the patient’s previous medical/dental records, prescription and/or physical confirmation of the medication that the patient was taking. The inclusion criteria for the study were: (1) patients with an oro-facial abscess of odontogenic origin; (2) patients with a “closed” non-draining abscess; and (3) patients with positive antibiotic history in the past 3-5 days for the same or any other complaint. Patients with abscesses draining intraorally/extraorally and patients with no history of previous empirical antibiotic history in the past 35 days were excluded from the study. An intravenous blood sample was collected from each patient for routine investigations of random blood sugar levels, white blood cell counts (total and differential) and haemoglobin percentage. Based on the blood investigation reports, patients were categorised into 2 groups — Group I: immunocompromised patients (diabetes mellitus and quantitative leucocyte disorders) and Group II: medically fit patients. Pus sample collection from the abscesses was done by aspiration using a needle and syringe. Permucosal or percutaneous aspiration was done using a sterile 18-gauge needle and a 10-mL disposable syringe. The site of aspiration, intraoral or extraoral, was chosen after palpation. Aspiration was done after adequate regional anaesthesia. Care was taken not to contaminate the sample by ensuring that the local anaesthetic solution was injected away from the site of aspiration. The site of aspiration was painted with a sterile gauze soaked in undiluted povidone-iodine solution and wiped with a dry sterile gauze. This was done three times sequentially to ensure maximum disinfection of the site of aspiration. Finally, a sterile dry gauze was used to wipe the area clean of any residual povidone-iodine solution before aspiration. Maximum sample was aspirated with a single entry of the aspirating needle. After aspiration, air was expelled from the syringe without causing aerosolisation. The aspirated sample 273
Microbiology of Odontogenic Abscesses
was immediately inoculated in the transport medium after excess air from the syringe was discarded. Thioglycolate broth dispensed in an airtight glass vial as supplied by the microbiologist was used as a transport medium. Fresh broth was made every week according to the manufacturer’s directions. Sterilised medium was dispensed into sterilised bottles and closed with sterile rubber caps. The opening of the bottle, with the rubber caps, was sealed externally with aluminium covers. On receipt of the specimen at the laboratory, the inoculated broth was immediately aspirated using a new sterile, disposable syringe and needle. Cultures and smears for detection of bacterial and fungal agents were then carried out. The specimen was inoculated on blood agar (BA) that was incubated aerobically at 37°C, Brucella blood agar (BBA) that was incubated anaerobically at 37°C in an anaerobic workstation (Don Whitley, India), and chocolate agar (CA) that was incubated at 37°C in an atmosphere of 10% CO2 (Forma Scientific, MA, USA). The specimen was then inoculated on Sabouraud’s dextrose agar that was incubated at 25°C in a cooling incubator (Remi, Mumbai, India). All the above media were prepared by reconstituting the commercially available dehydrated media from HiMedia, Mumbai, India. If the cultures on BA, CA and thioglycolate broth showed no growth at the end of 48 hours, they were placed in a cooling incubator. Fungal cultures were incubated for up to 1 month before discarding for negative culture. Anaerobically incubated BBA cultures were incubated for up to 14 days before discarding for negative culture. Three to four smears from the specimen were made using a cytospin machine (Shandon, UK); one smear was used for detection of fungi using potassium hydroxide (KOH)-calcofluor white preparation and one was used for Gram staining for bacteria. The KOH-calcofluor white preparation was seen under a fluorescent microscope using a violet filter. Antibiotic sensitivity studies for the aerobic isolates were done by the standard Kirby-Bauer disk diffusion technique. Antibiotics used were penicillin G (10 units), ciprofloxacin (5 μg), clindamicin (10 μg), vancomycin (30 μg), gentamicin (10 μg), cefotaxime 274
(30 μg) and ceftazidime (30 μg). Quality control was carried out using standard strains of Escherichia coli (American Type Culture Collection [ATCC] 25922), Pseudomonas aeruginosa (ATCC 27853), Staphylococcus aureus (ATCC 25923) and Enterococcus faecalis (ATCC 29212). The various organisms isolated are listed in Table 1. The number of negative cultures noted in both extremes of age was lower than that in the middleage group. The first molar teeth were the most commonly involved in abscesses (n = 54). Teeth involved in abscesses were equally distributed in all 4 quadrants of the dentition. The upper incisors, lower lateral incisors and canines were not responsible for any Organism
Number
Propionibacterium acne
1
2
Viridans streptococci
48
3
Enterococcus faecalis
20
4
Staphylococcus aureus
8
5
Staphylococcus aureus Biotype I
1
6
Staphylococcus aureus Biotype II
1
7
Streptococcus pneumoniae
5
8
Staphylococcus epidermidis
4
9
Group F Streptococci
2
10
Streptococcus Biotype I
3
11
Streptococcus Biotype II
3
12
Haemophilus species
3
13
Klebsiella pneumoniae
5
14
Candida albicans
2
15
Streptococcus faecalis
2
16
Enterobacter aerogenes
1
17
Acinetobacter calcoaceticus
1
1
18
Flavobacterium species
1
19
Streptococcus (nutritional variant)
1
20
Citrobacter diversus
1
21
Providencia rettgeri
1
22
Pseudomonas stutzeri
1
23
Non-haemolytic Streptococcus
1
24
Beta haemolytic Streptococcus
1
25
Alpha haemolytic Streptococcus
1
26
Neisseria flava
1
27
Micrococcus
1
Table 1. Bacterial species isolated.
Asian J Oral Maxillofac Surg Vol 18, No 4, 2006
Kulkarni, Narayanan
110
Submental
Sensitivity 100
Dentoalveolar
Resistance
90
Sublingual
Multiple
Negative
80
Triple
70 Percent of isolates
Ludwigs
Double Single
Submandibular Palatal Pericoronal
60 50 40 30
Canine 20
Buccal 10
0
2
4
6
8
10
12
14
16
18
20 0
Percent of isolates
in
cill
i Pen
Figure 1. Occurrence of bacteria according to sites of abscesses.
n
aci
flox
ro Cip
e e n in yci mic azidim toxim com enta t fa f n e e a C G C V n
yci
am
d Clin
Figure 3. Antibiogram of Gram-negative organisms. 100 90
Isolates
Frequency
Sensitivity
Single
53
Resistance
Double
24
Triple
5
Negative
18
Percent of isolates
80 70 60
Table 2. Number of isolates per sample.
50
number of isolates per sample significantly influenced the antibiotic activity, but the most important factor responsible for activity of any antibiotic in cases of mixed cultures was the species of organism and its Gram-staining characteristics (Table 2).
40 30 20 10 0
e e n n n icin yci yci aci dim toxim flox indam ncom entam eftazi a f o r e a C G C V Cl Cip in
cill
i Pen
Figure 2. Antibiogram of Gram-positive organisms.
abscess formation. Buccal space abscesses were most commonly seen, followed by dentoalveolar abscesses (Figure 1). The organisms isolated from the study samples were tested against 7 antibiotics for susceptibility. The results are grouped according to the Gramstaining characteristics of the isolates. The results are summarised in Figures 2 and 3, respectively. The Asian J Oral Maxillofac Surg Vol 18, No 4, 2006
Discussion Various studies have shown that the usually harmless commensals of the oral cavity turn pathogenic under certain circumstances leading to abscess formation. Thus, the oral cavity can be considered to act as a reservoir for the various potentially pathogenic bacteria responsible for abscess formation.5 The model of microbial succession is accepted in odontogenic infections. However, the central role of facultative streptococci is disputed in view of the aerotolerance of anaerobes by virtue of the ability of superoxide dismutase elaborated by obligate anaerobes to render 2% to 8% aerotolerance.1 275
Microbiology of Odontogenic Abscesses
Previously, there was much debate over the microbiological aspects of an odontogenic abscess. In the 1970s, it was thought that odontogenic infections were predominated by aerobic and microaerophilic organisms, mainly staphylococci and streptococci.16 It is now known that odontogenic abscesses are of polymicrobial origin with obligate anaerobic and facultative anaerobic organisms being predominant. The organisms most commonly implicated in odontogenic orofacial abscesses are Prevotella species, Porphyromonas species, peptostreptococci, Fusobacterium, Bacteroides and viridans streptococci.1-8,13,15,18-27 The in vitro antibiotic susceptibility determination techniques, although not definitive, can be used as a guideline for treatment since many organisms show differences in susceptibility to particular antibiotics in a microbiological laboratory and in vivo environment.28 Liquid gas chromatography and recent molecular techniques are commonly used for rapid diagnosis of the causative pathogen; however, this does not aid in the choice of antibiotic.25 Thus, culture and sensitivity testing remain the tests of choice and the most important diagnostic tool in the management of infection. Only a few studies addressing the patient population with a history of previous antibiotic administration (empiric or therapeutic) have been cited in the literature. The effect of such incomplete and inappropriate antibiotic administration on the bacteriological ecosystem in an abscess needs to be investigated in detail. This study is an attempt to identify the changes in the patterns of isolated bacteria in this particular patient population. Needle aspiration of the exudate from odontogenic infections is the gold standard technique of sampling. Commensal bacteria thrive on the epithelial membranes of the human body. Swabbing the skin or mucosa with 70% alcohol, tincture of iodine or chlorhexidine is the commonly recommended disinfection technique. 8,25,26 To achieve regional anaesthesia, local anaesthetic solution was deposited away from the region of the abscess to ensure that the sample was not contaminated. The technique of sampling used in this study was an 276
adaptation of the techniques recommended by Williams et al26 and Oguntebi et al.25 Ideally, the inoculation of samples for anaerobic culture should be done immediately after aspiration. In situations where a time gap is expected before processing the sample, an appropriate transport medium should be used.27 Tally et al found that oxygen tolerance of freshly isolated anaerobes from various clinical specimens was up to 10% and all the organisms tolerated 8 hours of oxygen in room air.28 These data indicate that brief exposure to oxygen during bench procedures in a clinical set up would not be deleterious to the anaerobic organisms present in the clinical specimen. In this study, thioglycolate broth sealed in a sterile glass vial with an airtight rubber cap and aluminium seal was used. The viability of obligate anaerobes in thioglycolate broth is not affected for up to 48 hours.29 The dehydrated medium, as supplied by the manufacturer, was used according to the manufacturer’s directions. Certain ingredients were added to enhance the viability of anaerobes during the transport period as recommended by Claros et al.29 The transport medium consisted of enriched thioglycolate broth containing pancreatic digest of casein, papaic digest soybean meat, trypticase peptone, glucose, sodium chloride, agar, L-cysteine, vitamin K, Hemin, thioglycolic acid and sodium bicarbonate in distilled water solution. Thioglycolic acid maintains the reduced redox potential in the broth, while vitamin K, Hemin, glucose, etc. support the nutritional requirements of the bacteria in the sample.27,29 A direct comparison of the results of this study can only be done with the report of Sklavounos et al.30 In the report by von Konow et al, the antibiotic history of patients (n = 17) has been mentioned; however, the bacteriology was not discussed for those particular cases.24 A total of 120 microorganisms were isolated in this study, with an average of 2.7 species isolated per sample: obligate anaerobe isolates (n = 1), facultative anaerobic/aerobic organisms (n = 117) and yeast (Candida albicans; n = 2) [Table 3]. A significantly high number of negative cultures was noted (n = 18), Asian J Oral Maxillofac Surg Vol 18, No 4, 2006
Kulkarni, Narayanan Species characteristics
Frequency
Obligate anaerobic Gram positive
1
Aerobic/facultative Gram positive
102
Facultative Gram negative
15
Yeast
2
Table 3. Frequency of various organisms isolated.
which greatly differs from that reported in other studies in the literature.4,6,7,18,19,24,31-33 Streptococci thrive in biofilms.3,34,35 A biofilm is a unique matrix comprising various organisms present in a complex state. The microorganisms in the biofilms interact with each other by a process known as quantum sensing.3 Experimental evidence suggests that existence in a biofilm imparts protection from antibodies and phagocytes, and increases drug resistance.3 It is hypothesised that the penetration of drugs into the biofilm layer is inhibited, thus sparing these organisms from the action of the antibiotic. Some authors speculated that, due to a change in the microenvironment of the biofilm, the porin structure also changes, thus rendering antibiotic resistance to the organism.3 It has been demonstrated that Streptococcus mutans has a unique ability to acquire chromosome-encoded antibiotic resistance from dead cells in the biofilm.35 Thus, natural genetic transformability expressed by these organisms in a biofilm might explain the reason for persistence of this particular group of organisms in an abscess after empiric antibiotic therapy. Another possibility is the development of a unique phenotype in the growing biofilm, which assumes a low metabolic state, thus evading the action of antibiotic agents and becoming reactivated once the antibiotic is withdrawn.3 One important result of the antibiotic sensitivity reports of viridans streptococci in this study was the occurrence of resistance to clindamycin in one case and to vancomycin in another case. Presence of vancomycin-resistant Enterococcus was not noticed in the isolates from the study. Streptococcus pneumoniae (pneumococcus) diagnosed by confirmation with the optochin test since some species from viridans streptococci resemble this organism in colony characteristics,27,36 Asian J Oral Maxillofac Surg Vol 18, No 4, 2006
was reported at a higher frequency as compared to that in the literature. One other frequently isolated Gram-positive organism was Staphylococcus epidermidis. This organism is again commonly disregarded as a contaminant and is known to be present in high numbers on the skin. On intraoral aspiration, chances of this organism contaminating the study sample are low and, importantly, S. epidermidis is not known to inhabit the oral cavity in significant numbers.8,12,16, Candida albicans was isolated in 2 cases. Although C. albicans is a commensal in the oral cavity, it is known to cause infection only in immunocompromised patients or in case of antibiotic abuse or long-term antibiotic treatment. Occurrence of such opportunistic organisms in samples from odontogenic infections in patients with an apparently good systemic condition is a worrying sign. This report is comparable to that of Sklavounos et al.30 Penicillin G showed excellent (97.05%) activity against the Gram-positive aerobic/facultative anaerobic isolates. S. aureus was the only isolate with significant (25%) resistance to penicillin. Penicillin resistance as high as 25% has been reported in oral anaerobic pathogens.9,11 Ciprofloxacin had the most promising activity against the isolates from the study samples. Ciprofloxacin is not a drug of choice for treatment of odontogenic infections,2,9,12 but considering the differences in inclusion criteria in the data reported in the literature and in this study, previous antibiotic exposure appears to have an influence on the antibiotic susceptibility results. The changing trends in odontogenic infections are not simply due to the change in taxonomy and nomenclature in the microbiological world,16,37 but also due to the changes in the patterns of presentations and changing clinical practices. The change in patterns of occurrence of bacteria in this particular patient group is an alarming sign. In this study, failure to isolate the commonly implicated obligate anaerobes may also be attributed to a failure of the transport systems used. Use of other systems such as the Amies agar gel transport system may be tried,38 but this would not rule out the possibility of a major influence of inappropriate antibiotic usage in the general 277
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population. Further investigations are called for to establish a definitive explanation for such findings. In conclusion, orofacial odontogenic abscesses in patients with a history of empiric antibiotic therapy are predominated by Gram-positive facultative organisms, especially viridans streptococci. The exact role of anaerobic organisms in persistent infections following empiric antibiotic therapy is questionable and further investigations using molecular biological techniques are required. Penicillin G, as tested in this study, remains the drug of choice for treating odontogenic infections regardless of a history of previous antibiotic administration, and the incidence of penicillin resistance appears to be negligible in this study.
References 1. Stefanopoulos PK, Kolokotronis AE. The clinical significance of anaerobic bacteria in acute orofacial odontogenic infections. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2004;98:398-408. 2. Maestre-Vera JR. Treatment options in odontogenic infection. Med Oral Patol Oral Cir Bucal. 2004;9(Suppl 25-31):19-24. 3. Dirks SJ, Terezhalmy GT. The patient with an odontogenic infection. Quintessence Int. 2004;35:482-502. 4. Gill Y, Scully C. Orofacial odontogenic infections: review of microbiology and current treatment. Oral Surg Oral Med Oral Pathol. 1990;70:155-8. 5. Gutirrez Perez JL, Perea-Perez EJ, Romero-Ruiz, GironGonzalez JA. Orofacial infections of odontogenic origin. Med Oral Pathol Oral Cir Bucal. 2004;9:280-7. 6. Heimdahl A, von Konow L, Satoh T, Nord CE. Clinical appearance of orofacial infections of odontogenic origin in relation to microbiological findings. J Clin Microbiol. 1985;22:299-302. 7. Kuriyama T, Karasawa T, Nakagawa K, Saiki Y, Yamamoto E, Nakamura S. Bacteriologic features and antimicrobial susceptibility in isolates from orofacial odontogenic infections. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2000;90:600-8. 8. Peterson LJ, Edward Ellis E, Hupp JR, Tucker MR, editors. Contemporary oral and maxillofacial surgery. 4th ed. St Louis, USA: Mosby Co; 2003. 9. Topazian RG, Goldberg MH, Hupp JR, editors. Oral and Maxillofacial Infections. 4th ed. W.B. Saunders Company; 2002. 278
10. Bascones A, Aguirre JM, Bermejo A, Blanco A, GayEscoda C, Gonzalez-Moles MA, Gutierrez PL, Jimenez SY, Liebana UJ, Lopez-Marcos JF, Maestre VJ, Perea PE, Prieto PJ, Rodriguez JC. Consensus statement on antimicrobial treatment of odontogenic bacterial infections. Med Oral Pathol Oral Cir Bucal. 2004;9:363-76. 11. Flynn TR, Halpern LR. Antibiotic selection in head and neck infections. Oral Maxillofac Surg Clin North Am. 2003; 15:17-38. 12. Goldberg M. Antibiotics – old friends and new acquaintances. A clinician’s view. Oral Maxillofac Surg Clin North Am. 2001;13:15-30. 13. Moenning JE, Nelson CL, Koller RB. Microbiology and chemotherapy of odontogenic infections. J Oral Maxillofac Surg. 1989;47:976-85. 14. Harrison JW, Svec TA. The beginning of the end of the antibiotic era? Part I. The problem: abuse of the “miracle drugs.” Quintessence Int. 1998;29:151-62. 15. Har-El G, Aroesty JH, Shaha A, Lucente FE. Changing trends in deep neck abscess. A retrospective study of 110 patients. Oral Surg Oral Med Oral Pathol. 1994;77:446-50. 16. Haug RH. The changing microbiology of maxillofacial infections. Current concepts in the management of maxillofacial infections. Oral Maxillofac Surg Clin North Am. 2003; 15:1-15. 17. Prieto-Prieto J, Calvo A. Microbiological basis of oral infections and sensitivity to antibiotics. Med Oral Patol Oral Cir Bucal. 2004;9(Suppl 15-8):11-4. 18. Aderhold L, Knothe H, Frenkel G. The bacteriology of dentogenous pyogenic infections. Oral Surg Oral Med Oral Pathol. 1981;52:583-7. 19. Brook I, Grimm S, Kielich RB. Bacteriology of acute periapical abscess in children. J Endod. 1981;7:378-80. 20. Bartlett JG, O’Keefe P. The bacteriology of perimandibular space infections.J Oral Surg. 1979;37:407-9. 21. Greenberg RN, James RB, Marier RL, Wood WH, Sanders CV, Kent JN. Microbiologic and antibiotic aspects of infections in the oral and maxillofacial region. J Oral Surg. 1979;37:873-84. 22. Haug RH, Hoffman MJ, Indresano AT. An epidemiologic and anatomic survey of odontogenic infections. J Oral Maxillofac Surg. 1991;49:976-80. 23. Kannangara DW, Thadepalli H, McQuirter JL. Bacteriology and treatment of dental infections. Oral Surg Oral Med Oral Pathol. 1980;50:103-9. 24. von Konow L, Nord CE, Nordenram A. Anaerobic bacteria in dentoalveolar infections. Int J Oral Surg. 1981;10:313-22. Asian J Oral Maxillofac Surg Vol 18, No 4, 2006
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25. Oguntebi B, Slee AM, Tanzer JM, Langeland K. Predominant microflora associated with human dental periapical abscesses. J Clin Microbiol. 1982;15:964-6. 26. Williams BL, McCann GF, Schoenknecht FD. Bacteriology of dental abscesses of endodontic origin. J Clin Microbiol. 1983;18:770-4. 27. Baron EJ, Peterson LR, Finegold SM, editors. Cultivation and isolation of viable pathogens. In: Bailey and Scott’s diagnostic microbiology. 9th ed. St Louis, USA: Mosby Co; 1994. 28. Tally FP, Stewart PR, Sutter VL, Rosenblatt JE. Oxygen tolerance of fresh clinical anaerobic bacteria. J Clin Microbiol. 1975;1:161-4. 29. Claros MC, Citron DM, Goldstein EJ. Survival of anaerobic bacteria in various thioglycolate and chopped meat broth formulations. J Clin Microbiol. 1995;33:2505-7. 30. Sklavounos A, Legakis NJ, Ioannidou H, Patrikiou A. Anaerobic bacteria in dentoalveolar abscesses. Int J Oral Maxillofac Surg. 1986;15:288-91. 31. Kulekci G, Inanc D, Kocak H, Kasapoglu C, Gumru OZ. Bacteriology of dentoalveolar abscesses in patients who have received empirical antibiotic therapy. Clin Infect Dis. 1996;23(Suppl 1):S51-3. 32. Lewis MA, MacFarlane TW, McGowan DA. Quantitative bacteriology of acute dento-alveolar abscesses. J Med
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Microbiol. 1986;21:101-4. 33. von Konow L, Kondell PA, Nord CE, Heimdahl A. Clindamycin versus phenoxymethylpenicillin in the treatment of acute orofacial infections. Eur J Clin Microbiol Infect Dis. 1992;11:1129-35. 34. Facklam R. What happened to the streptococci: overview of taxonomic and nomenclature changes. Clin Microbiol Rev. 2002;15:613-30. 35. Li YH, Lau PC, Lee JH, Ellen RP, Cvitkovitch DG. Natural genetic transformation of Streptococcus mutans growing in biofilms. J Bacteriol. 2001;183:897-908. 36. Colle JG, Miles RS, Watt B. Test for identification of bacteria. In: Fraser AG, Marimon BP, Simons SA, editors. Mackie and McCartney’s practical medical microbiology. 14th ed. New York: Churchill Livingstone;1996. 37. Storoe W, Haug RH, Lillich TT. The changing face of odontogenic infections. J Oral Maxillofac Surg. 2001;59: 739-48. 38. Hindiyeh M, Acevedo V, Carroll KC. Comparison of three transport systems (Starplex Starswab II, the New Copan Vi-Pak Amies agar gel collection and transport swabs, and BBL Port-A-Cul) for maintenance of anaerobic and fastidious aerobic organisms. J Clin Microbiol. 2001;39: 377-80.
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Bacteriological Profile and Antibiotic Sensitivity Patterns of Odontogenic Abscesses in Patients with a History of Empiric Antibiotic Therapy Amol S Kulkarni, Vinod Narayanan Department of Oral and Maxillofacial Surgery, College of Dental Surgery, Saveetha Institute of Medical and Technical Sciences, Chennai, Tamil Nadu, India
Abstract Objective: To determine the microbiology of odontogenic abscesses in patients with a history of empiric antibiotic administration. Patients and Methods: Percutaneous or permucosal aspiration of pus was carried out from closed nondraining abscesses using strict disinfection techniques and processing in an aerobic and anaerobic environment. Antibiotic sensitivity testing was performed by the Kirby-Bauer method. Results: A total of 120 isolates were reported from 100 study samples. In all, 27 different strains of microorganisms were isolated from the study group, with an average of 2.7 isolates per sample. Viridans streptococci were the most frequently isolated organisms. Of 7 antibiotics tested, penicillin G, clindamycin and ciprofloxacin had excellent activity against the isolates. Conclusions: Orofacial odontogenic abscesses in patients with a history of empiric antibiotic therapy predominantly contain Gram-positive facultative organisms, especially viridans streptococci. The precise role of anaerobic organisms in persistent infections following empiric antibiotic therapy is debatable, and further investigations using molecular biological techniques are required. Penicillin G, as tested in this study, remains the drug of choice for treating odontogenic infections. The incidence of penicillin resistance was found to be negligible in this study. Key words: Bacteriology, Microbial sensitivity tests, Penicillin G, Viridans streptococci
Introduction Infection may be defined as the invasion and multiplication of micro organisms in body tissues resulting in local cellular injury due to competitive metabolism, toxin production, intracellular replication or antigenantibody reaction. Infections can be autogenous, i.e., caused by the host flora that becomes pathogenic for some reason, or may be due to cross-infection. In cases of odontogenic infection, the former is the commonest cause, but cross-infection may occur due to the use of non-sterile injections and contaminated needles.1
Vera in 2004 proposed a simple classification of oral infections into 2 large groups — odontogenic and non-odontogenic. 2 Odontogenic infections (caries, periodontitis, periapical abscess, periodontal abscess, pericoronitis, pulpitis, osteitis and infections of aponeurotic spaces) can be subdivided into primary (usually related to progression of caries) and secondary (secondary to traumatic injury, dental extraction or surgery) infections. Non-odontogenic infections include those affecting the mucosa, salivary glands and bones.
Correspondence: Prof Vinod Narayanan, Department of Oral and Maxillofacial Surgery, College of Dental Surgery, Saveetha Institute of Medical and Technical Sciences (Deemed University), 172 Poonamalle High Road, Chennai 600 077, Tamil Nadu, India. Tel: (91 44) 2626 0990; Fax: (91 44) 2680 0892; E-mail: [email protected]
Most oral infections are primarily odontogenic in nature.1 Orofacial abscesses of odontogenic origin are a common sequela of deeply carious or periodontally involved teeth or pericoronal infections. Most of these infections can be managed by tooth
272
© 2006 AsianAsian Association J Oral of Maxillofac Oral and Surg Maxillofacial Vol 18, No Surgeons. 4, 2006
Kulkarni, Narayanan
extraction, endodontic treatment and/or surgical drainage without the use of antimicrobials.3-9 However, antimicrobials need to be prescribed in acute fascial space infections or in case of immunocompromised patients. The choice of antimicrobials is case-specific and based on factors including laboratory data, patient health, age, allergies, drug absorption, distribution ability and plasma levels. The cost of drugs, type and location of infection and previous antibiotic history also need to be considered.3,9-13 Although fatal infections of odontogenic origin are uncommon, infectious diseases remain the leading cause of death worldwide. Shifting infectious disease patterns and their manifestations have become a topic of discussion. It is debatable as to whether the infection patterns are actually changing14 and whether the characteristics of pathogenic bacteria causing odontogenic infections are today different from those reported in the literature. There has been a noticeable change in the pathogenic genera isolated from odontogenic abscesses over the past 2 to 3 decades. This may be attributable to the taxonomic changes in the microbiological world and perhaps the use of better diagnostic techniques.1,8,9,13,15-17 However, very few studies have specifically investigated the bacteriological profiles and sensitivity patterns in isolates from individuals with odontogenic abscesses and a history of incomplete antibiotic therapy, which is a commonly encountered situation in developing countries. The aim of this study was to determine the microbiology of odontogenic abscesses in patients with a history of empiric antibiotic therapy.
Patients and Methods This prospective study included patients reporting to the outpatient division of the Department of Oral and Maxillofacial Surgery between January and August 2005. Patients of all age groups with the complaint of face swellings were screened clinically and considered for the study. Detailed history and thorough clinical examinations were performed to determine the presence of an odontogenic abscess. Radiological examination of the area of chief complaint was done to confirm Asian J Oral Maxillofac Surg Vol 18, No 4, 2006
the causative tooth. Any known systemic disease condition was noted along with the medication for the condition. Antibiotic history was noted in detail. History of drug administration was verified on reviewing the patient’s previous medical/dental records, prescription and/or physical confirmation of the medication that the patient was taking. The inclusion criteria for the study were: (1) patients with an oro-facial abscess of odontogenic origin; (2) patients with a “closed” non-draining abscess; and (3) patients with positive antibiotic history in the past 3-5 days for the same or any other complaint. Patients with abscesses draining intraorally/extraorally and patients with no history of previous empirical antibiotic history in the past 35 days were excluded from the study. An intravenous blood sample was collected from each patient for routine investigations of random blood sugar levels, white blood cell counts (total and differential) and haemoglobin percentage. Based on the blood investigation reports, patients were categorised into 2 groups — Group I: immunocompromised patients (diabetes mellitus and quantitative leucocyte disorders) and Group II: medically fit patients. Pus sample collection from the abscesses was done by aspiration using a needle and syringe. Permucosal or percutaneous aspiration was done using a sterile 18-gauge needle and a 10-mL disposable syringe. The site of aspiration, intraoral or extraoral, was chosen after palpation. Aspiration was done after adequate regional anaesthesia. Care was taken not to contaminate the sample by ensuring that the local anaesthetic solution was injected away from the site of aspiration. The site of aspiration was painted with a sterile gauze soaked in undiluted povidone-iodine solution and wiped with a dry sterile gauze. This was done three times sequentially to ensure maximum disinfection of the site of aspiration. Finally, a sterile dry gauze was used to wipe the area clean of any residual povidone-iodine solution before aspiration. Maximum sample was aspirated with a single entry of the aspirating needle. After aspiration, air was expelled from the syringe without causing aerosolisation. The aspirated sample 273
Microbiology of Odontogenic Abscesses
was immediately inoculated in the transport medium after excess air from the syringe was discarded. Thioglycolate broth dispensed in an airtight glass vial as supplied by the microbiologist was used as a transport medium. Fresh broth was made every week according to the manufacturer’s directions. Sterilised medium was dispensed into sterilised bottles and closed with sterile rubber caps. The opening of the bottle, with the rubber caps, was sealed externally with aluminium covers. On receipt of the specimen at the laboratory, the inoculated broth was immediately aspirated using a new sterile, disposable syringe and needle. Cultures and smears for detection of bacterial and fungal agents were then carried out. The specimen was inoculated on blood agar (BA) that was incubated aerobically at 37°C, Brucella blood agar (BBA) that was incubated anaerobically at 37°C in an anaerobic workstation (Don Whitley, India), and chocolate agar (CA) that was incubated at 37°C in an atmosphere of 10% CO2 (Forma Scientific, MA, USA). The specimen was then inoculated on Sabouraud’s dextrose agar that was incubated at 25°C in a cooling incubator (Remi, Mumbai, India). All the above media were prepared by reconstituting the commercially available dehydrated media from HiMedia, Mumbai, India. If the cultures on BA, CA and thioglycolate broth showed no growth at the end of 48 hours, they were placed in a cooling incubator. Fungal cultures were incubated for up to 1 month before discarding for negative culture. Anaerobically incubated BBA cultures were incubated for up to 14 days before discarding for negative culture. Three to four smears from the specimen were made using a cytospin machine (Shandon, UK); one smear was used for detection of fungi using potassium hydroxide (KOH)-calcofluor white preparation and one was used for Gram staining for bacteria. The KOH-calcofluor white preparation was seen under a fluorescent microscope using a violet filter. Antibiotic sensitivity studies for the aerobic isolates were done by the standard Kirby-Bauer disk diffusion technique. Antibiotics used were penicillin G (10 units), ciprofloxacin (5 μg), clindamicin (10 μg), vancomycin (30 μg), gentamicin (10 μg), cefotaxime 274
(30 μg) and ceftazidime (30 μg). Quality control was carried out using standard strains of Escherichia coli (American Type Culture Collection [ATCC] 25922), Pseudomonas aeruginosa (ATCC 27853), Staphylococcus aureus (ATCC 25923) and Enterococcus faecalis (ATCC 29212). The various organisms isolated are listed in Table 1. The number of negative cultures noted in both extremes of age was lower than that in the middleage group. The first molar teeth were the most commonly involved in abscesses (n = 54). Teeth involved in abscesses were equally distributed in all 4 quadrants of the dentition. The upper incisors, lower lateral incisors and canines were not responsible for any Organism
Number
Propionibacterium acne
1
2
Viridans streptococci
48
3
Enterococcus faecalis
20
4
Staphylococcus aureus
8
5
Staphylococcus aureus Biotype I
1
6
Staphylococcus aureus Biotype II
1
7
Streptococcus pneumoniae
5
8
Staphylococcus epidermidis
4
9
Group F Streptococci
2
10
Streptococcus Biotype I
3
11
Streptococcus Biotype II
3
12
Haemophilus species
3
13
Klebsiella pneumoniae
5
14
Candida albicans
2
15
Streptococcus faecalis
2
16
Enterobacter aerogenes
1
17
Acinetobacter calcoaceticus
1
1
18
Flavobacterium species
1
19
Streptococcus (nutritional variant)
1
20
Citrobacter diversus
1
21
Providencia rettgeri
1
22
Pseudomonas stutzeri
1
23
Non-haemolytic Streptococcus
1
24
Beta haemolytic Streptococcus
1
25
Alpha haemolytic Streptococcus
1
26
Neisseria flava
1
27
Micrococcus
1
Table 1. Bacterial species isolated.
Asian J Oral Maxillofac Surg Vol 18, No 4, 2006
Kulkarni, Narayanan
110
Submental
Sensitivity 100
Dentoalveolar
Resistance
90
Sublingual
Multiple
Negative
80
Triple
70 Percent of isolates
Ludwigs
Double Single
Submandibular Palatal Pericoronal
60 50 40 30
Canine 20
Buccal 10
0
2
4
6
8
10
12
14
16
18
20 0
Percent of isolates
in
cill
i Pen
Figure 1. Occurrence of bacteria according to sites of abscesses.
n
aci
flox
ro Cip
e e n in yci mic azidim toxim com enta t fa f n e e a C G C V n
yci
am
d Clin
Figure 3. Antibiogram of Gram-negative organisms. 100 90
Isolates
Frequency
Sensitivity
Single
53
Resistance
Double
24
Triple
5
Negative
18
Percent of isolates
80 70 60
Table 2. Number of isolates per sample.
50
number of isolates per sample significantly influenced the antibiotic activity, but the most important factor responsible for activity of any antibiotic in cases of mixed cultures was the species of organism and its Gram-staining characteristics (Table 2).
40 30 20 10 0
e e n n n icin yci yci aci dim toxim flox indam ncom entam eftazi a f o r e a C G C V Cl Cip in
cill
i Pen
Figure 2. Antibiogram of Gram-positive organisms.
abscess formation. Buccal space abscesses were most commonly seen, followed by dentoalveolar abscesses (Figure 1). The organisms isolated from the study samples were tested against 7 antibiotics for susceptibility. The results are grouped according to the Gramstaining characteristics of the isolates. The results are summarised in Figures 2 and 3, respectively. The Asian J Oral Maxillofac Surg Vol 18, No 4, 2006
Discussion Various studies have shown that the usually harmless commensals of the oral cavity turn pathogenic under certain circumstances leading to abscess formation. Thus, the oral cavity can be considered to act as a reservoir for the various potentially pathogenic bacteria responsible for abscess formation.5 The model of microbial succession is accepted in odontogenic infections. However, the central role of facultative streptococci is disputed in view of the aerotolerance of anaerobes by virtue of the ability of superoxide dismutase elaborated by obligate anaerobes to render 2% to 8% aerotolerance.1 275
Microbiology of Odontogenic Abscesses
Previously, there was much debate over the microbiological aspects of an odontogenic abscess. In the 1970s, it was thought that odontogenic infections were predominated by aerobic and microaerophilic organisms, mainly staphylococci and streptococci.16 It is now known that odontogenic abscesses are of polymicrobial origin with obligate anaerobic and facultative anaerobic organisms being predominant. The organisms most commonly implicated in odontogenic orofacial abscesses are Prevotella species, Porphyromonas species, peptostreptococci, Fusobacterium, Bacteroides and viridans streptococci.1-8,13,15,18-27 The in vitro antibiotic susceptibility determination techniques, although not definitive, can be used as a guideline for treatment since many organisms show differences in susceptibility to particular antibiotics in a microbiological laboratory and in vivo environment.28 Liquid gas chromatography and recent molecular techniques are commonly used for rapid diagnosis of the causative pathogen; however, this does not aid in the choice of antibiotic.25 Thus, culture and sensitivity testing remain the tests of choice and the most important diagnostic tool in the management of infection. Only a few studies addressing the patient population with a history of previous antibiotic administration (empiric or therapeutic) have been cited in the literature. The effect of such incomplete and inappropriate antibiotic administration on the bacteriological ecosystem in an abscess needs to be investigated in detail. This study is an attempt to identify the changes in the patterns of isolated bacteria in this particular patient population. Needle aspiration of the exudate from odontogenic infections is the gold standard technique of sampling. Commensal bacteria thrive on the epithelial membranes of the human body. Swabbing the skin or mucosa with 70% alcohol, tincture of iodine or chlorhexidine is the commonly recommended disinfection technique. 8,25,26 To achieve regional anaesthesia, local anaesthetic solution was deposited away from the region of the abscess to ensure that the sample was not contaminated. The technique of sampling used in this study was an 276
adaptation of the techniques recommended by Williams et al26 and Oguntebi et al.25 Ideally, the inoculation of samples for anaerobic culture should be done immediately after aspiration. In situations where a time gap is expected before processing the sample, an appropriate transport medium should be used.27 Tally et al found that oxygen tolerance of freshly isolated anaerobes from various clinical specimens was up to 10% and all the organisms tolerated 8 hours of oxygen in room air.28 These data indicate that brief exposure to oxygen during bench procedures in a clinical set up would not be deleterious to the anaerobic organisms present in the clinical specimen. In this study, thioglycolate broth sealed in a sterile glass vial with an airtight rubber cap and aluminium seal was used. The viability of obligate anaerobes in thioglycolate broth is not affected for up to 48 hours.29 The dehydrated medium, as supplied by the manufacturer, was used according to the manufacturer’s directions. Certain ingredients were added to enhance the viability of anaerobes during the transport period as recommended by Claros et al.29 The transport medium consisted of enriched thioglycolate broth containing pancreatic digest of casein, papaic digest soybean meat, trypticase peptone, glucose, sodium chloride, agar, L-cysteine, vitamin K, Hemin, thioglycolic acid and sodium bicarbonate in distilled water solution. Thioglycolic acid maintains the reduced redox potential in the broth, while vitamin K, Hemin, glucose, etc. support the nutritional requirements of the bacteria in the sample.27,29 A direct comparison of the results of this study can only be done with the report of Sklavounos et al.30 In the report by von Konow et al, the antibiotic history of patients (n = 17) has been mentioned; however, the bacteriology was not discussed for those particular cases.24 A total of 120 microorganisms were isolated in this study, with an average of 2.7 species isolated per sample: obligate anaerobe isolates (n = 1), facultative anaerobic/aerobic organisms (n = 117) and yeast (Candida albicans; n = 2) [Table 3]. A significantly high number of negative cultures was noted (n = 18), Asian J Oral Maxillofac Surg Vol 18, No 4, 2006
Kulkarni, Narayanan Species characteristics
Frequency
Obligate anaerobic Gram positive
1
Aerobic/facultative Gram positive
102
Facultative Gram negative
15
Yeast
2
Table 3. Frequency of various organisms isolated.
which greatly differs from that reported in other studies in the literature.4,6,7,18,19,24,31-33 Streptococci thrive in biofilms.3,34,35 A biofilm is a unique matrix comprising various organisms present in a complex state. The microorganisms in the biofilms interact with each other by a process known as quantum sensing.3 Experimental evidence suggests that existence in a biofilm imparts protection from antibodies and phagocytes, and increases drug resistance.3 It is hypothesised that the penetration of drugs into the biofilm layer is inhibited, thus sparing these organisms from the action of the antibiotic. Some authors speculated that, due to a change in the microenvironment of the biofilm, the porin structure also changes, thus rendering antibiotic resistance to the organism.3 It has been demonstrated that Streptococcus mutans has a unique ability to acquire chromosome-encoded antibiotic resistance from dead cells in the biofilm.35 Thus, natural genetic transformability expressed by these organisms in a biofilm might explain the reason for persistence of this particular group of organisms in an abscess after empiric antibiotic therapy. Another possibility is the development of a unique phenotype in the growing biofilm, which assumes a low metabolic state, thus evading the action of antibiotic agents and becoming reactivated once the antibiotic is withdrawn.3 One important result of the antibiotic sensitivity reports of viridans streptococci in this study was the occurrence of resistance to clindamycin in one case and to vancomycin in another case. Presence of vancomycin-resistant Enterococcus was not noticed in the isolates from the study. Streptococcus pneumoniae (pneumococcus) diagnosed by confirmation with the optochin test since some species from viridans streptococci resemble this organism in colony characteristics,27,36 Asian J Oral Maxillofac Surg Vol 18, No 4, 2006
was reported at a higher frequency as compared to that in the literature. One other frequently isolated Gram-positive organism was Staphylococcus epidermidis. This organism is again commonly disregarded as a contaminant and is known to be present in high numbers on the skin. On intraoral aspiration, chances of this organism contaminating the study sample are low and, importantly, S. epidermidis is not known to inhabit the oral cavity in significant numbers.8,12,16, Candida albicans was isolated in 2 cases. Although C. albicans is a commensal in the oral cavity, it is known to cause infection only in immunocompromised patients or in case of antibiotic abuse or long-term antibiotic treatment. Occurrence of such opportunistic organisms in samples from odontogenic infections in patients with an apparently good systemic condition is a worrying sign. This report is comparable to that of Sklavounos et al.30 Penicillin G showed excellent (97.05%) activity against the Gram-positive aerobic/facultative anaerobic isolates. S. aureus was the only isolate with significant (25%) resistance to penicillin. Penicillin resistance as high as 25% has been reported in oral anaerobic pathogens.9,11 Ciprofloxacin had the most promising activity against the isolates from the study samples. Ciprofloxacin is not a drug of choice for treatment of odontogenic infections,2,9,12 but considering the differences in inclusion criteria in the data reported in the literature and in this study, previous antibiotic exposure appears to have an influence on the antibiotic susceptibility results. The changing trends in odontogenic infections are not simply due to the change in taxonomy and nomenclature in the microbiological world,16,37 but also due to the changes in the patterns of presentations and changing clinical practices. The change in patterns of occurrence of bacteria in this particular patient group is an alarming sign. In this study, failure to isolate the commonly implicated obligate anaerobes may also be attributed to a failure of the transport systems used. Use of other systems such as the Amies agar gel transport system may be tried,38 but this would not rule out the possibility of a major influence of inappropriate antibiotic usage in the general 277
Microbiology of Odontogenic Abscesses
population. Further investigations are called for to establish a definitive explanation for such findings. In conclusion, orofacial odontogenic abscesses in patients with a history of empiric antibiotic therapy are predominated by Gram-positive facultative organisms, especially viridans streptococci. The exact role of anaerobic organisms in persistent infections following empiric antibiotic therapy is questionable and further investigations using molecular biological techniques are required. Penicillin G, as tested in this study, remains the drug of choice for treating odontogenic infections regardless of a history of previous antibiotic administration, and the incidence of penicillin resistance appears to be negligible in this study.
References 1. Stefanopoulos PK, Kolokotronis AE. The clinical significance of anaerobic bacteria in acute orofacial odontogenic infections. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2004;98:398-408. 2. Maestre-Vera JR. Treatment options in odontogenic infection. Med Oral Patol Oral Cir Bucal. 2004;9(Suppl 25-31):19-24. 3. Dirks SJ, Terezhalmy GT. The patient with an odontogenic infection. Quintessence Int. 2004;35:482-502. 4. Gill Y, Scully C. Orofacial odontogenic infections: review of microbiology and current treatment. Oral Surg Oral Med Oral Pathol. 1990;70:155-8. 5. Gutirrez Perez JL, Perea-Perez EJ, Romero-Ruiz, GironGonzalez JA. Orofacial infections of odontogenic origin. Med Oral Pathol Oral Cir Bucal. 2004;9:280-7. 6. Heimdahl A, von Konow L, Satoh T, Nord CE. Clinical appearance of orofacial infections of odontogenic origin in relation to microbiological findings. J Clin Microbiol. 1985;22:299-302. 7. Kuriyama T, Karasawa T, Nakagawa K, Saiki Y, Yamamoto E, Nakamura S. Bacteriologic features and antimicrobial susceptibility in isolates from orofacial odontogenic infections. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2000;90:600-8. 8. Peterson LJ, Edward Ellis E, Hupp JR, Tucker MR, editors. Contemporary oral and maxillofacial surgery. 4th ed. St Louis, USA: Mosby Co; 2003. 9. Topazian RG, Goldberg MH, Hupp JR, editors. Oral and Maxillofacial Infections. 4th ed. W.B. Saunders Company; 2002. 278
10. Bascones A, Aguirre JM, Bermejo A, Blanco A, GayEscoda C, Gonzalez-Moles MA, Gutierrez PL, Jimenez SY, Liebana UJ, Lopez-Marcos JF, Maestre VJ, Perea PE, Prieto PJ, Rodriguez JC. Consensus statement on antimicrobial treatment of odontogenic bacterial infections. Med Oral Pathol Oral Cir Bucal. 2004;9:363-76. 11. Flynn TR, Halpern LR. Antibiotic selection in head and neck infections. Oral Maxillofac Surg Clin North Am. 2003; 15:17-38. 12. Goldberg M. Antibiotics – old friends and new acquaintances. A clinician’s view. Oral Maxillofac Surg Clin North Am. 2001;13:15-30. 13. Moenning JE, Nelson CL, Koller RB. Microbiology and chemotherapy of odontogenic infections. J Oral Maxillofac Surg. 1989;47:976-85. 14. Harrison JW, Svec TA. The beginning of the end of the antibiotic era? Part I. The problem: abuse of the “miracle drugs.” Quintessence Int. 1998;29:151-62. 15. Har-El G, Aroesty JH, Shaha A, Lucente FE. Changing trends in deep neck abscess. A retrospective study of 110 patients. Oral Surg Oral Med Oral Pathol. 1994;77:446-50. 16. Haug RH. The changing microbiology of maxillofacial infections. Current concepts in the management of maxillofacial infections. Oral Maxillofac Surg Clin North Am. 2003; 15:1-15. 17. Prieto-Prieto J, Calvo A. Microbiological basis of oral infections and sensitivity to antibiotics. Med Oral Patol Oral Cir Bucal. 2004;9(Suppl 15-8):11-4. 18. Aderhold L, Knothe H, Frenkel G. The bacteriology of dentogenous pyogenic infections. Oral Surg Oral Med Oral Pathol. 1981;52:583-7. 19. Brook I, Grimm S, Kielich RB. Bacteriology of acute periapical abscess in children. J Endod. 1981;7:378-80. 20. Bartlett JG, O’Keefe P. The bacteriology of perimandibular space infections.J Oral Surg. 1979;37:407-9. 21. Greenberg RN, James RB, Marier RL, Wood WH, Sanders CV, Kent JN. Microbiologic and antibiotic aspects of infections in the oral and maxillofacial region. J Oral Surg. 1979;37:873-84. 22. Haug RH, Hoffman MJ, Indresano AT. An epidemiologic and anatomic survey of odontogenic infections. J Oral Maxillofac Surg. 1991;49:976-80. 23. Kannangara DW, Thadepalli H, McQuirter JL. Bacteriology and treatment of dental infections. Oral Surg Oral Med Oral Pathol. 1980;50:103-9. 24. von Konow L, Nord CE, Nordenram A. Anaerobic bacteria in dentoalveolar infections. Int J Oral Surg. 1981;10:313-22. Asian J Oral Maxillofac Surg Vol 18, No 4, 2006
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25. Oguntebi B, Slee AM, Tanzer JM, Langeland K. Predominant microflora associated with human dental periapical abscesses. J Clin Microbiol. 1982;15:964-6. 26. Williams BL, McCann GF, Schoenknecht FD. Bacteriology of dental abscesses of endodontic origin. J Clin Microbiol. 1983;18:770-4. 27. Baron EJ, Peterson LR, Finegold SM, editors. Cultivation and isolation of viable pathogens. In: Bailey and Scott’s diagnostic microbiology. 9th ed. St Louis, USA: Mosby Co; 1994. 28. Tally FP, Stewart PR, Sutter VL, Rosenblatt JE. Oxygen tolerance of fresh clinical anaerobic bacteria. J Clin Microbiol. 1975;1:161-4. 29. Claros MC, Citron DM, Goldstein EJ. Survival of anaerobic bacteria in various thioglycolate and chopped meat broth formulations. J Clin Microbiol. 1995;33:2505-7. 30. Sklavounos A, Legakis NJ, Ioannidou H, Patrikiou A. Anaerobic bacteria in dentoalveolar abscesses. Int J Oral Maxillofac Surg. 1986;15:288-91. 31. Kulekci G, Inanc D, Kocak H, Kasapoglu C, Gumru OZ. Bacteriology of dentoalveolar abscesses in patients who have received empirical antibiotic therapy. Clin Infect Dis. 1996;23(Suppl 1):S51-3. 32. Lewis MA, MacFarlane TW, McGowan DA. Quantitative bacteriology of acute dento-alveolar abscesses. J Med
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Microbiol. 1986;21:101-4. 33. von Konow L, Kondell PA, Nord CE, Heimdahl A. Clindamycin versus phenoxymethylpenicillin in the treatment of acute orofacial infections. Eur J Clin Microbiol Infect Dis. 1992;11:1129-35. 34. Facklam R. What happened to the streptococci: overview of taxonomic and nomenclature changes. Clin Microbiol Rev. 2002;15:613-30. 35. Li YH, Lau PC, Lee JH, Ellen RP, Cvitkovitch DG. Natural genetic transformation of Streptococcus mutans growing in biofilms. J Bacteriol. 2001;183:897-908. 36. Colle JG, Miles RS, Watt B. Test for identification of bacteria. In: Fraser AG, Marimon BP, Simons SA, editors. Mackie and McCartney’s practical medical microbiology. 14th ed. New York: Churchill Livingstone;1996. 37. Storoe W, Haug RH, Lillich TT. The changing face of odontogenic infections. J Oral Maxillofac Surg. 2001;59: 739-48. 38. Hindiyeh M, Acevedo V, Carroll KC. Comparison of three transport systems (Starplex Starswab II, the New Copan Vi-Pak Amies agar gel collection and transport swabs, and BBL Port-A-Cul) for maintenance of anaerobic and fastidious aerobic organisms. J Clin Microbiol. 2001;39: 377-80.
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