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Management of Antibiotic Resistant Organisms
Symposia
SYMPOSIUM ON MAXILLOFACIAL INFECTIONS Presented on Saturday, September 24, 2005, 1:00 pm—3:00 pm Moderator: Raymond P. White, Jr, DDS, PhD, Chapel Hill, NC
Pharmacology Update on Antimicrobial Agents Thomas R. Flynn, DMD, Boston, MA The development of new antibiotics slowed down in the 1990’s, possibly due to an oversupply of new antibiotics, largely cephalosporins. At the same time, new mechanisms of antibiotic resistance were developing among pathogenic bacteria. This decade saw the emergence of such highly resistant organisms as VISA, VRE, and Pseudomonas. In response to increased antimicrobial resistance, researchers have developed entire new families of antibiotics, such as the ketolides and the oxazolidinones, which are targeted primarily to highly antibiotic resistant Gram positive cocci, such as Staphylococcus aureus. In addition, established antibiotic families have been joined by new drugs with enhanced spectra, such as moxifloxacin and levofloxacin, among the fluoroquinolones. Side effects and drug interactions remain a problem for the antibiotics, however. The safety profile of the carbapenems has been improved by meropenem. Similarly, Azithromycin is a safer macrolide that has been shown to be effective in orofacial infections. The promise of even newer yet to be released antibiotics is tempered by their cost, by competition with other more profitable types of drugs, and by the amazing ability of bacteria of respond to the pressures of survival. References Flynn TR, Halpern LR: Antibiotic selection in head and neck infections. Oral Maxillofac Surg Clin North Am 15:17, 2003 File TM: Overview of resistance in the 1990s. Chest 115:3S, 1999 (suppl) Kuriyama T, Karasawa T, Nakagawa K, et al: Bacteriologic features and antimicrobial susceptibility in isolates from orofacial odontogenic infections. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 90:600, 2000
Infections in Immunocompromised Patients Thomas B. Dodson, DMD, MPH, Boston, MA The overall purpose of this presentation will be to review issues regarding the management of immunocompromised patients in the setting of oral and maxillofacial surgical practice. The specific aims of the presentation will be to: 1. Review primary and secondary immunodefiAAOMS • 2005
2. 3.
4.
5.
ciency states with an emphasis on the more common immunodeficiency states, eg, neutropenia following chemotherapy, HIV infection, diabetes, and chronic steroid therapy, Discuss the effect of immunodeficiency on wound healing, Review new or unusual pathogens associated with infections in immunocompromised subjects, Review the principles of management of immunocompromised subjects presenting for the evaluation and management of more common oral and maxillofacial surgical problems, and Discuss concepts for preventing postoperative complications in the immunocompromised patient. References
Dodson TB: Hematologic disorders, in Bennett JD, Rosenberg MB (eds): Medical Emergencies in Dentistry. Philadelphia, PA, Saunders, 2002, pp 389-208 Dodson TB: HIV status and the risk of post extraction complications. J Dental Res 76:1644, 1997 Dodson TB: Prediction of post extraction complications in HIVpositive patients. Oral Surg Oral Med Oral Pathol 84:474, 1997
Fungal Head and Neck Infections Alan A. Miyake, DDS, MD, Oklahoma City, OK Please see page 76.
Management of Antibiotic Resistant Organisms David W. Hecht, MD, Maywood, IL Antibiotic resistance among bacteria causing or associated with maxillofacial infections can result in failures to some empiric regimens. Maxillofacial infections often involve a mixture of aerobic, facultative anaerobic, and anaerobic bacteria with varied and increasing resistance to empiric antibiotic therapy. Key aerobic bacteria include Viridans and other streptococcal species, Actinobacillus, and spirochetes, which by and large remain sensitive to penicillin and other commonly used antibiotics. However, resistance to erythromycin and tetracycline for some organisms is now sufficiently prevalent that these agents are not generally recommended. Among some of the key anaerobic pathogens including Porphyromonas sp, Prevotella sp, Peptostreptococ21
Symposia cus sp, T. forsythia and Fusobacterium sp., antibiotic resistance has increased significantly. Beta-lactamase producing organisms account for more that 50% of strains for some species making them resistant to penicillin. Clindamycin and cefoxitin resistance is also increasing, especially among Prevotella sp. Resistance mechanisms and corresponding genes have been identified for some of the resistance phenotypes. The most reliable agents for the more resistant anaerobes include the beta-lactam/beta-lactamase inhibitor combinations, metronidazole, and carbapenems, with variable activity seen to moxifloxacin. Other pathogens complicating oral infections in the immunocompromised or complicated patient include enteric gram negative bacilli and S. aureus, which have a high degree of antibiotic susceptibility, often dependent on the clinical situation, previous antibiotic usage, and exposure to the hospital environment. Patients’ failing any of the accepted empiric therapies warrants culturing infected areas. While most microbiology laboratories can support isolation, identification, and susceptibility testing of aerobic and facultative anaerobic
organisms (as needed), most cannot or will not determine the susceptibility of anaerobic bacteria. Methods for testing the susceptibility of anaerobic bacteria are available, and although rarely employed, should be considered in therapeutic failures. Consideration of many factors may enter into the selection of antibiotic therapy for patients with maxillofacial infections. Awareness of resistance trends and appropriate culturing and susceptibility testing should optimize success of treatment strategies. References Hecht, DW. Prevalence of antibiotic resistance in anaerobic bacteria: worrisome developments. Clin Infect Dis. 2004; 39(1):92-7. Olsen HT, Walker CB, Caugant DA. Beta-lactamase production and antimicrobial susceptibility of subgingival bacteria from refractory periodontitis. Oral Microbiol Immunol. 2004, 19:303-308. Bahar H, et al. Antimicrobial resistance and beta-lactamase production of clinical isolates of prevotella and porphyromonas species. Chemotherapy 2005, 51:9-14. Koeth LM et al. Surveillance of susceptibility patterns in 1297 European and US anaerobic and capnophilic isolates to co-amoxiclav and five other antimicrobial agents. 2004, 53:1039-1044.
SYMPOSIUM ON THE DIAGNOSIS AND TREATMENT OF VASCULAR LESIONS Presented on Saturday, September 24, 2005, 1:00 pm—3:00 pm Moderator: Eric R. Carlson, DMD, MD, Knoxville, TN
Classification of Vascular Lesions Thomas B. Dodson, DMD, MPH, Boston, MA Classification of vascular lesions is one of the few areas in medicine or surgery where nomenclature has seriously impeded the understanding and management of a disease. The purpose of this presentation is to provide an understanding of the biological classification system of vascular lesions. In general, vascular lesions are classified as either hemangiomas or vascular malformations. The two categories of vascular lesions have fundamentally different etiologies and clinical presentations. Hemangiomas are vascular tumors demonstrating endothelial hyperplasia that enlarges by rapid cellular proliferation. Vascular malformations exhibit a normal rate of endothelial cell turnover and are structural abnormalities of arteries, veins, lymphatics, or some combination of these vascular entities, eg, arteriovenous malformation. Clinically, the hemangiomas is usually not present at birth, but in 30% of cases it may present as a red macule. The female to male ratio is 3 to 1. There is a rapid tumor growth after birth followed by slow invo22
lution over several years, resulting in a fibro-fatty mass. In contrast, vascular malformations are present at birth, although commonly undetected. The malformations grow commensurately as the child grows. The malformation may expand due to changes in blood or lymphatic flow, inflammation, or hormonal changes at puberty or during pregnancy. The female to male ratio is 1 to 1. The management of vascular lesions can be challenging. The nomenclature, however, should not contribute to the challenge. References Mulliken JB, Young AE: Vascular Birthmarks. Hemangiomas and Malformations. Philadelphia, PA, Saunders, 1988 Waner M, Suen JY: Hemangiomas and Vascular Malformations of the Head and Neck. New York, NY, Wiley-Liss, 1999
Contemporary Diagnostic Imaging of Vascular Lesions R. Kent Hutson, MD, Knoxville, TN Advances in computed tomography (CT), magnetic resonance imaging (MRI), and ultrasonography have imAAOMS • 2005
SYMPOSIUM ON MAXILLOFACIAL INFECTIONS Presented on Saturday, September 24, 2005, 1:00 pm—3:00 pm Moderator: Raymond P. White, Jr, DDS, PhD, Chapel Hill, NC
Pharmacology Update on Antimicrobial Agents Thomas R. Flynn, DMD, Boston, MA The development of new antibiotics slowed down in the 1990’s, possibly due to an oversupply of new antibiotics, largely cephalosporins. At the same time, new mechanisms of antibiotic resistance were developing among pathogenic bacteria. This decade saw the emergence of such highly resistant organisms as VISA, VRE, and Pseudomonas. In response to increased antimicrobial resistance, researchers have developed entire new families of antibiotics, such as the ketolides and the oxazolidinones, which are targeted primarily to highly antibiotic resistant Gram positive cocci, such as Staphylococcus aureus. In addition, established antibiotic families have been joined by new drugs with enhanced spectra, such as moxifloxacin and levofloxacin, among the fluoroquinolones. Side effects and drug interactions remain a problem for the antibiotics, however. The safety profile of the carbapenems has been improved by meropenem. Similarly, Azithromycin is a safer macrolide that has been shown to be effective in orofacial infections. The promise of even newer yet to be released antibiotics is tempered by their cost, by competition with other more profitable types of drugs, and by the amazing ability of bacteria of respond to the pressures of survival. References Flynn TR, Halpern LR: Antibiotic selection in head and neck infections. Oral Maxillofac Surg Clin North Am 15:17, 2003 File TM: Overview of resistance in the 1990s. Chest 115:3S, 1999 (suppl) Kuriyama T, Karasawa T, Nakagawa K, et al: Bacteriologic features and antimicrobial susceptibility in isolates from orofacial odontogenic infections. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 90:600, 2000
Infections in Immunocompromised Patients Thomas B. Dodson, DMD, MPH, Boston, MA The overall purpose of this presentation will be to review issues regarding the management of immunocompromised patients in the setting of oral and maxillofacial surgical practice. The specific aims of the presentation will be to: 1. Review primary and secondary immunodefiAAOMS • 2005
2. 3.
4.
5.
ciency states with an emphasis on the more common immunodeficiency states, eg, neutropenia following chemotherapy, HIV infection, diabetes, and chronic steroid therapy, Discuss the effect of immunodeficiency on wound healing, Review new or unusual pathogens associated with infections in immunocompromised subjects, Review the principles of management of immunocompromised subjects presenting for the evaluation and management of more common oral and maxillofacial surgical problems, and Discuss concepts for preventing postoperative complications in the immunocompromised patient. References
Dodson TB: Hematologic disorders, in Bennett JD, Rosenberg MB (eds): Medical Emergencies in Dentistry. Philadelphia, PA, Saunders, 2002, pp 389-208 Dodson TB: HIV status and the risk of post extraction complications. J Dental Res 76:1644, 1997 Dodson TB: Prediction of post extraction complications in HIVpositive patients. Oral Surg Oral Med Oral Pathol 84:474, 1997
Fungal Head and Neck Infections Alan A. Miyake, DDS, MD, Oklahoma City, OK Please see page 76.
Management of Antibiotic Resistant Organisms David W. Hecht, MD, Maywood, IL Antibiotic resistance among bacteria causing or associated with maxillofacial infections can result in failures to some empiric regimens. Maxillofacial infections often involve a mixture of aerobic, facultative anaerobic, and anaerobic bacteria with varied and increasing resistance to empiric antibiotic therapy. Key aerobic bacteria include Viridans and other streptococcal species, Actinobacillus, and spirochetes, which by and large remain sensitive to penicillin and other commonly used antibiotics. However, resistance to erythromycin and tetracycline for some organisms is now sufficiently prevalent that these agents are not generally recommended. Among some of the key anaerobic pathogens including Porphyromonas sp, Prevotella sp, Peptostreptococ21
Symposia cus sp, T. forsythia and Fusobacterium sp., antibiotic resistance has increased significantly. Beta-lactamase producing organisms account for more that 50% of strains for some species making them resistant to penicillin. Clindamycin and cefoxitin resistance is also increasing, especially among Prevotella sp. Resistance mechanisms and corresponding genes have been identified for some of the resistance phenotypes. The most reliable agents for the more resistant anaerobes include the beta-lactam/beta-lactamase inhibitor combinations, metronidazole, and carbapenems, with variable activity seen to moxifloxacin. Other pathogens complicating oral infections in the immunocompromised or complicated patient include enteric gram negative bacilli and S. aureus, which have a high degree of antibiotic susceptibility, often dependent on the clinical situation, previous antibiotic usage, and exposure to the hospital environment. Patients’ failing any of the accepted empiric therapies warrants culturing infected areas. While most microbiology laboratories can support isolation, identification, and susceptibility testing of aerobic and facultative anaerobic
organisms (as needed), most cannot or will not determine the susceptibility of anaerobic bacteria. Methods for testing the susceptibility of anaerobic bacteria are available, and although rarely employed, should be considered in therapeutic failures. Consideration of many factors may enter into the selection of antibiotic therapy for patients with maxillofacial infections. Awareness of resistance trends and appropriate culturing and susceptibility testing should optimize success of treatment strategies. References Hecht, DW. Prevalence of antibiotic resistance in anaerobic bacteria: worrisome developments. Clin Infect Dis. 2004; 39(1):92-7. Olsen HT, Walker CB, Caugant DA. Beta-lactamase production and antimicrobial susceptibility of subgingival bacteria from refractory periodontitis. Oral Microbiol Immunol. 2004, 19:303-308. Bahar H, et al. Antimicrobial resistance and beta-lactamase production of clinical isolates of prevotella and porphyromonas species. Chemotherapy 2005, 51:9-14. Koeth LM et al. Surveillance of susceptibility patterns in 1297 European and US anaerobic and capnophilic isolates to co-amoxiclav and five other antimicrobial agents. 2004, 53:1039-1044.
SYMPOSIUM ON THE DIAGNOSIS AND TREATMENT OF VASCULAR LESIONS Presented on Saturday, September 24, 2005, 1:00 pm—3:00 pm Moderator: Eric R. Carlson, DMD, MD, Knoxville, TN
Classification of Vascular Lesions Thomas B. Dodson, DMD, MPH, Boston, MA Classification of vascular lesions is one of the few areas in medicine or surgery where nomenclature has seriously impeded the understanding and management of a disease. The purpose of this presentation is to provide an understanding of the biological classification system of vascular lesions. In general, vascular lesions are classified as either hemangiomas or vascular malformations. The two categories of vascular lesions have fundamentally different etiologies and clinical presentations. Hemangiomas are vascular tumors demonstrating endothelial hyperplasia that enlarges by rapid cellular proliferation. Vascular malformations exhibit a normal rate of endothelial cell turnover and are structural abnormalities of arteries, veins, lymphatics, or some combination of these vascular entities, eg, arteriovenous malformation. Clinically, the hemangiomas is usually not present at birth, but in 30% of cases it may present as a red macule. The female to male ratio is 3 to 1. There is a rapid tumor growth after birth followed by slow invo22
lution over several years, resulting in a fibro-fatty mass. In contrast, vascular malformations are present at birth, although commonly undetected. The malformations grow commensurately as the child grows. The malformation may expand due to changes in blood or lymphatic flow, inflammation, or hormonal changes at puberty or during pregnancy. The female to male ratio is 1 to 1. The management of vascular lesions can be challenging. The nomenclature, however, should not contribute to the challenge. References Mulliken JB, Young AE: Vascular Birthmarks. Hemangiomas and Malformations. Philadelphia, PA, Saunders, 1988 Waner M, Suen JY: Hemangiomas and Vascular Malformations of the Head and Neck. New York, NY, Wiley-Liss, 1999
Contemporary Diagnostic Imaging of Vascular Lesions R. Kent Hutson, MD, Knoxville, TN Advances in computed tomography (CT), magnetic resonance imaging (MRI), and ultrasonography have imAAOMS • 2005