- Email: [email protected]
Spirochetes in periodontal disease
for 40% of dog bite--related deaths in a 10-yr period (21).
Conclusion The high prevalence of animal bites in the United States clearly suggests that prevention could be improved. Educaring people about animal safety and the risks involved in approaching or
Emerg. Med. 9:79-83. Edwards, M. S. 1992. Infections due to human and animal bites, p. 2334-2338. In R. Feigin and J. Cherry (eds.) Textbook of pediatric infectious diseases, 3rd ed., volume II. 5. Wiley, J. F. 1990 Mammalian bites: review of evaluation and management. Clin. Pediatr. 29:283-287.
4.
keeping wild animals as pets is the first line of defense. When bites do occur, aggressive wound management, updating tetanus immune status, assessing rabies risk to provide immunoprophylaxis when necessary, and judicious use of empiric antibiotic therapy in high-risk situations remain standard care. Further evaluation of the clinical situations in which antimicrobial prophylaxis is warranted continues to be necessary. Until such time the recommendations provided here offer a reasonable approach
6.
Sacks, J. J., R. W. Sauin, and S.E. Bonzo. 1989. Dog bite-related fatalities from 1979 through 1988. JAMA 262:1489-1492. 8. McDonough, J. J., P. J. Stem, and J.W. Alexander. 1987. Management of anireal and human bites and resulting human infections. Curt. Clin. Top. Infect. Dis. 8:11-36. 9. Pinckney, L. E. and L. A. Kennedy. 1980. Fractures of the infant skull caused by animal bites. Am. J. Roentgenol. 135:179-180.
to this all too common problem. References 1. Baker, M. D. 1989. Bites and scratches
10. Centers for Disease Control. 1993. Human rabies---New York. Morbid. Mortal. Weekly Rep. 42:799-806.
when pets fight back. Contemporary Pediatr. 6:76-84. 2. Goldstein, E. J. 1989. Management of human and animal bite wounds. J. Am. Acad. Dermatol. 21:1275-1279. 3. Aghababian, R. V. and J. E. Conte Jr. 1980. Mammalian bite wounds. Ann.
11. Centers for Disease Control. 1991. Summary of notifiable diseases, United States. Morbid. Mortal. Weekly Rep. 40:53. 12. Houff, S. A. et al. 1979. Human-to human transmission of rabies virus by corneal transplant. N. Engl. J. Med. 300:603-604.
13. Committee on Infectious Diseases. 1991. Rabies, p. 391-398. In Report of the Committee on Infectious Diseases, 22rid ed. Elk Grove, IL. 14. Helmick, C. G. 1983. The epidemiology of human rabies post-exposure prophylaxis, 1980--1981. JAMA 250:1990. 15. Uhaa, I. J. et al. 1992 Benefits and costs of using an orally absorbed vaccine to control rabies in raccoons. J. Am. Vet. Med. Assoc 201:1873. 16. Callaham, M. 1980. Prophylactic antibiotics in common dog bite wounds: a controlled study. Ann. Emerg. Med. 9:410-414. 17. Elenbass, R. M., W. K. McNalmey, and W.A. Robinson. 1984. Evaluation of IXOphylactic oxacillin m cat bite wounds. Ann. Emerg. Med. 13:155-157. 18. Brook, I. 1987. Microbiology of human and animal bite wounds in children. Pediatr. InfecL Dis. J. 6:29-32. 19. Goldstein, E. J., D. M. Citron, and S. M. Finegold. 1984. Role of anaerobic bacteria in bite wound infections, Rev. Infect. Dis. 6 (Suppl. 1):s177-s183. 20. Feder, H. M., J. D. Shanley, and J. A. Barbara. 1987. Review of 59 patients hospitalized with animal bites. Pediatr. Infect. Dis. J. 6:24-28.
Editorial
Spirochetes in Periodontal Disease George R. Riviere, D.D.S., Ph.D. School of Dentistry, Oregon Health Sciences University, Portland, OR 97201-3097 The oral cavity is colonized by a great diversity of microorganisms, Most niches contain a stable indigenous microflora but teeth and their supporting tissues, collectively called the periodontium, represent the most dynamic microenvironment in the mouth. A variety of factors, including tooth morphology, diet, and oral hygiene, influence bacterial colonization and proliferation at these sites, In periodontal health, tooth surfaces immediately above the free gingival margin are coated predominantly by nonmotile, gram-positive cocci and
rods. Cleaned tooth surfaces are recolonized rapidly but as long as plaque accumulation is restricted, periodontal tissues tolerate the presence of the normal oral flora. Dental plaque is formed from accumulation of bacteria and incorporation of dietary substances and organic material from the host into the biomass. Buildup of supragingival plaque creates sequestered environments within plaque itself and within the gingival sulcus, the space between tooth and gum. These isolated niches support proliferation of anaerobic, gramnegative bacteria. If supmgingival plaque is controlled, subgingival plaque is tinlikely to form (1). If plaque is allowed to accumulate, the number and diversity of microorganisms increase rapidly, i
148
0196-4399/94/$0.00 + 07.00
Mature plaque may contain 1011 bacteria per gram, representing as many as 300 species (2-4). The presence of plaque, particularly subgingival plaque, is strongly associated with the etiology and pathogenesis of periodontal disease. It is not known whether this assoelation is a result of nonspecific effects of plaque components on periodontal tissues or whether disease is a result of the virulence of specific bacteria. Spirochetes are difficult to fmd in the oxygen-rich gingival sulci of people with healthy periodontal tissues. Colonization and proliferation of these anaerobic bacteria are further restricted by the paucity of plaque associated with periodontal health. Conversely, spirochetes often flourish in subgingival plaque at
Hi © 1994 Elsevier Science Inc.
Clinical Microbiology Newsletter 16:19,t994
sites of periodontal disease, and they are one of the types of bacteria in subgingival plaque that have the strongest association with deterioration of periodontal tissues (5). When appropriate techniques are employed for their detection, spirochetes are found to be among the predominant bacteria at diseased sites (6), at refractory treated sites, and at sites of recurrent disease (7). Unidentiffed spirochetes have been observed within connective tissue near lesions of necrotizing ulcerative gingivitis (8, 9), suggesting that at least some oral spirechetes may be invasive, Although oral spirochetes in plaque suspensions are easily identified with darldield or phase microscopy, they are difficult to isolate among the many faster growing and less fastidious competitors found in subgingival plaque. At the present time, five species of oral treponema have been isolated and propagated in pure culture--they are Treponema denticola, T. pectinovorum, T. scoliodontum, T. socranskii, and T. vincentii. These cultivable oral species represent only a ~rnallportion of the diverse spirochete morphotypes that have been observed in plaque samples (10). Most oral spirochetes have never been isolated or identified, and their pathogenic potential remains unknown, Treponema denticola is probably the most frequently isolated oral spirochete (11) and it is certainly the most studied of the oral treponema. T. denticola is probably an opportunistic organism. It is found in low numbers in plaque from children and young adults with healthy periodontal tissues (12) and it is one of the predominant bacteria in plaque assoelated with periodontal disease (13, 14). T. denticola is often found in association with Porphyromonas gingivalis (15), suggesting that infection by T. denticola may be dependent upon prior colonization by other bacteria. T. denticola expresses a variety of outer membrahe antigens (16, 17) and four serologic variants axe recognized (18, 19). T. denticola strains proved to be identical based on 16S rRNA sequence analysis and they have been positioned in a phylogenetic tree next to the host-indigenous, nonpathogenic T. phagedenis (20). T. denticola has several characteristics that suggest pathogenic potenClinical Microbiology Newsletter 16:19,1994
tial. For example, T. denticola possesses proteolytic enzyr ~es that could contribute to tissue deg~~dation (21, 22), and trypsin-like enzy ~e activity of T. denticola correlates w ell with periodontal disease and the e ffectiveness of treatment (23). T. det ticola, but not T. vincentii, suppresse: fibroblast proliferation in vitro (24) and lymphocyte responses tO mitogens (25) by inhibiting DNA, RNA, and protein synthesis in a dose.dependent manner. T. denticola has gly~oproteins that mediate erythrocyte agglutination (26, 27), and it attaches to human, rat, and guinea pig cells in vitro (28, 29). Under some conditions, anaehment can damage epithelial cells in culture (30). However, T. deno'cola, T. scoliodontum, and T. vincentii do not attach to rabbit fibroblasts (31), indicaring that attachment potential of oral spirochetes may be limited compared with the pathogen T. pallidum (31). People with healthy periodontal tissues and patientsl with various periodontal diseases have similar levels of serum antibodies to 7". denticola, 1". vincentii, and T. socranskii (32, 33). It has been reported that antibody levels to many plaque bacteria, including T. vincentii, decline following treatment, but antibodies to T. denticola persist at pretreatment levels (34). Maintenance of antibody levels after periodontal therapy, which always includes plaque removal, suggests either that debridement did not eradicate!antigen, or that T. denticola antibodies were maintained by similar bacteria at other sites. The importance of serum antibodies to oral spirochetes is difficult to assess because serum contains antibodies to virtually all plaqOe microorganisms. Furthermore, thelplethora of common and cross-reacting bacterial antigens makes interpretation of serologic assays difficult when whole cells or crude antigens are used to ¢letectpolymorphic, polyclonal serum antibodies, It is also diffigult to determine whether certain qharacteristics of oral spirochetes relate to virulence. For example, the ability to adhere to surfaces or to other microorganisms is a characteristic common ~o all oral bacteria, Adherence is neCessary to resist displacement by th~ flow of saliva and by the mechanical debridement of mastica© 1994 Elsevier Science Inc.
tion. Since T. denticola and other oral treponema are found in the presence of healthy periodontal tissues, tissue breakdown is not an inevitable consequence of their ability to adhere to epithelial cells or of their ability to produce extracellular ptoteolytic enzymes. One should also use caution when evaluating the meaning of relative numbers of bacteria in plaque. Proliferation of spirochetes and other bacteria at diseased sites is I m ~ b l y a reflection of the supportive natme of the environment rather than an indication of pathogenicity. Another approach to studying the oral spirochetes has been to determine whether any of them have distinguishing characteristics in common with known pathogens. For example, although T. pallidum expresses cross-reacting antigenic determinants (35, 36), pathogenic treponema also share unique antigens not found on nonpathogenic spirochetes (37, 38). Monoclonal antibodies to antigens located on 47-, 37-, 14-, and 12-kDa molecules (39, 40) serve to distinguish T. pallidum subspecies (41) from host-indigenous, nonpathogenic spirochetes. Plaque from people with healthy periodontal tissues did not contain spirechetes that react with T. pallidum monoclonal antibodies (18). However, pathogen-related oral spirochetes (PROS) were found in plaque from patients with acute necrotizing ulcerative gingivitis, from patients with chronic adult periodontitis (42, 43), and from HIV-infected subjects with periodontal disease (44). T. pallidum monoclonal antibodies detected PROS antigen in connective tissue around necrotic gingiva (45). T. denticola monoclonal antibodies also detected antigen near gingival lesions (45). However, PROS were the only plaque microorganisms able to invade living tissue in an in vitro assay (46). No cultivable oral spirochete, including T. denticola, proved to be invasive under these experimental conditions. In the manner that infection with T. carateum induces serum antibodies against pathogen-restricted antigens of T. pallidum (47), serum from PROS-infected subjects reacted with 47-, 37-, 14-, and 12-kDa molecules from T. pallidum in immunoblot assays (42). These sera were unreactive in VDRL and FTA0196-4399~t4/$0.00 + 07.00
149
ABS tests. People with healthy periodontal tissues did not have serum anti-
bodies that reacted with pathogenrestricted determinants from T. palh'dum (42). Reactivity with T. pallidum mono-
clonal antibodies does not mean that
PROS are pathogens. The ability to invade tissue does not mean that PROS cause any form o f periodontal disease. More studies are needed before PROS can be f'Lrmlyassociated with the etiology and/or pathogenesis o f periodontal disease. Further characterization o f PROS is difficult because they resist isolation and cultivation. Traditional approaches that have been used to isolate other oral spirochetes have not produced a pure culture o f any PROS. PROS may prove to be more host-dependent than other oral spirochetes and may be as difficult to grow in vilro as T. pallidum. In conclusion, oral spirochetes occupy an intriguing but enigmatic position among the hundreds of bacteria found in plaque. The well-established, strong positive correlation of spirochetes with periodontal deterioration suggests that some oral spirochetes may be important in the etiology and/or pathogenesis o f periodontal disease. More effort is needed to isolate and
identify oral spirochetes, and more research is needed to define the pathogenic potential of new isolates, References 1.
Katsanoulas, T., I. Renee, and R. Attstrom. 1992. The effect of supragingival plaque control on the composition of subgingival flora in periodontal pockets. J. Ciin. Periodontol. 19:760-765. 2. Harwood, C. S. and E. Canale-Parola. 1984. Ecology of spirochetes. Ann. Rev. Microbiol. 38:161-192. 3. Newman, H. N. 1984. Plaque and chronic inflammatory disease. A question of ecology. J. Clin. Periodontol. 7:533--541. 4. Newman, M. G. 1984. Anaerobic oral and dental infection. Rev. Infect. Dis. 6:107-114. 5. Loesche, W. J. 1993. Bacterial mediators in periodontal disease. Clin. Infect. Dis. $203-$210. 6. Loesche, W. J. et al. 1992. Comparison of various detection methods for periodontopathic bacteria: can culture be considered the primary reference standard? J. Clin. Microbiol. 30:418--426. 150
0196-4399/94/$0.00 + 07.00
7.
Listgarten, M. A., L. Chem-Hsiung, and V. Young. 1993. Microbial composition and pattern periodontitis. J. Periodontoi. 64:155-161. 8. Listgarten, M. A. and D. W. Lewis. 1967. The distribution of spirochetes in the lesion of acute necrotizing ulcerative gingivitis: an electron microscopic and statistical survey. J. Periodontol. 38:379-386. 9. Courtois, G. J. Ill, C. M. Cobb, and W. J. Killoy. 1983. Acute necrotizing ulcerative gingivitis. A transmission dectron microscope study. J. Periodontol. 54:671-679. 10. Loesche, W. J. 1988. The role of spirochetes in periodontal disease. Adv. Dent. Res. 2:275-283. 11. Chart, E. C. et al. 1993. Treponema denticola (ex Brumpt 1925) sp. nov., nom. rev., and identification of new spirochete isolates from periodontal pockets. Int. J. Syst. Bacteriol. 43:196-203. 12. Barron, S. L. et al. 1991. Use of monoclonal antibodies to enumerate spirochetes and identify Treponema denticola in dental plaque of children, adolescents and young adults. Oral Microbiol. Immunol. 6:97-101. 13. Simonson, L. G. et al. 1988. Quantitative relationship of Treponema denticola to severity of periodontal disease. Infect. Immun. 56:726-728 14. Riviere, G. R. et al. 1992. Relative proportions of pathogen-related oral spirochetes (PROS) and Treponema denticola in supragingival and subgingival plaque from patients with periodontitis. J. Periodontol. 63:131-136. 15. Simonson, L. G. et al. 1992. Bacterial synergy of Treponema denticola and Porphyromonas gingivalis in a multinational population. Oral Microbiol. Immunol. 7:111-112. 16. Yotis, W. W. et al. 1991. Biochemical properties of the outer membrane of Treponema denticola. J. Clin. Microbiol. 29:1397-1406. 17. Tall, B. D. and R. K. Nauman. 1994. Outer membrane antigens of oral treponema species. J. Med. Mierobiol. 40:62-69. 18. Keams, E. A. et al. 1991. Characterization of monoclonal antibodies to two Treponema denticola serotypes by the indirect fluorescent antibody assay, Microbios 65:14%153. 19. Simonson, L., H. Morton, and R. Schutt. 1989. Treponema denticola serotypes and solubilization of type-specific antigen. J. Dent. Res. 68:357 © 1994ElsevierScienceInc.
(Abstract 1401). 20. Paster, B. J. et al. 1991. Phylogenet~c analysis of the spirochetes. J. Bacteriol. 173:6101-6109. 21. Grenier, D., V.-J. Uitto, and B. C. McBride. 1990. Cellular location of a Treponema denticola chymotrypsinlike protease--importance of the protease in migration through the basement membrane. Infect. Immun. 58:347-351. 22. Loesche, W. J. et al. 1990. Development of a diagnostic test for anaerobic periodontal infections based on plaque hydrolysis of benzoyl-DL-argininenaphthylamide. J. Clin. Microbiol. 28:1551-1559. 23. 1.x~sche, W. J., J. Giordano, and P. P. Hujoel. 1990. The utility of the BAHIA test for monitoring anaerobic infection due to spirochetes (Treponema denticola) in periodontal disease. J. Dent. Res. 69:1696-1702. 24. Boehringer, H., N. S. Taichman, and B. I. Shenker. 1984. Suppression of fibroblast proliferation by oral spirochetes. Infect. Inunun. 45:155-159. 25. Shenker, B. J., M. A. Listgarten, and N. S. Taichman. 1984. Suppression of human lymphocyte responses by oral spirochetes: a monocyte-dependent phenomenon. J. lmmunol. 132:2039-2045. 26. Grenier, D. 1991. Characteristics of hemolytic and hemagglutinating activities of Treponema denticola. Oral Microbiol. Immunol. 6:246-249. 27. Mikx, F. H. M. and R. A. C. Kenlers. 1992. Hemagglutination activity of Treponema denticola grown in serum-free medium in continuous culture. Infect. Immun. 60:1761-1766. 28. Olsen, I. 1984. Attachment of Treponema denticola to cultured human epithelial cells. Scand. L Dent. Res. 92:55-63. 29. Keulers, R.A. et al. 1993. Attachment of Treponeraa denticola strains to monolayers of epithelial cells of different origin. Oral Microbiol. Immunol. 8:84-88. 30. Reijntjens F. M. et al. 1986. Adherence of oral treponemes and their effect on morphological damage and detachment of epithelial cells in vitro. Infect. Iramun. 51:642---647. 31. Fitzgerald, T. J. et al. 1977. Characterization of the attachment of Treponema pallida~n (Nichols strain) to cultured mammalian cells and the potential relationship of attachment to pathogenicity. Infect. Immun. I8:467--478. 32. Tew, J. G. et al, 1985. Serum antibodies ClinicalMicrobiologyNewsletter16:19,1994
33.
34.
35.
36.
37.
in young adult humans reactive with periodontitis associated treponemes. L Pcriodont. Res. 20:.580-590. Lai, C.-H. et al. 1986. Serum IgA and IgG antibodies to Treponemavincentii and Treponema denticola in adult periodontitis, juvenile periodontitis and periodontally healthy subjects. J. Clin. Periodontol. 13:752-757. Awkhil, I. et al. 1988. The effects of periodontal therapy on serum antibody (IgG) levds to plaque microorganisms. J. Clin. Periodontal. 15:544-550. Hanff, P. A., L N. Miller, and M.A. LoveR. 1983. Molecular characterization of common treponemal antigens. Infect. Immun. 40:825-828. Wos, S. M. and K. Wicher. 1986. Extensire cross-reactivity between Treponema pallidum and cultivable lreponemas demonstrated by sequential immunoabsorption. Int. Archs. Appl. Allergy Immunol. 79:282-285. Baker-Zander, S.A. and S.A. Lukehart. 1983. Molecular basis of immunologi-
38.
39.
40.
41.
42.
cal crossreacfivity between Treponema pallidum and Treponemapertenue. Infect. Immun. 42:634--638. Bakcr-Zander,S. A. and S. A. Lakehart. 1984. Antigeniccross-reactivitybetween Treponema pallidum and otherpathogenic members of the family Spirechaetaceae.Infect. Immun. 46:116-121. Lukehart, S. A. et al. 1985. Characterization of monoclonal antibodies to Treponemapallidum. J. lmmunol. 134:585-592. Marchitto, K. S., C. K. SeUandGrossling, and M. V. Norgard. 1986. Molecular specificities of monoclonal antibodies directed against virulent Treponema pallidum. Infect. Immun. 51:168-176. Marchitto, K. S. et al. 1984. Monoclonal antibody analysis of specific antigenic similarities among pathogenic Treponemapallidum subspecies. Infect. Immun. 45:660-666. Riviere, G. R. et al. 1991. Identification of spirochetes related to Treponemapal-
43.
44.
45.
46.
47.
lidam in necrotiz~ ulcerative gingivitis and chronic periodontitis. N. Engl. J. Med 325:539-543. Riviere, G. R. et al. 1992. Relative proportions of pathogen-related oral spirochetes (PROS) and Treponema denticola in supragingival and subgingival plaque from patients with periodontitis. J. Periodontol. 63:131-136. Rosenstein, D. I., G. R. Riviere, and K. S. Elott. 1994. HIV-associated periodontal disease: new oral spirochete found. J. Am. Dent. Assoc. 124:76-80. Riviere, G. R. et al. 1991. pathogen-related spirochetes identified within 8ingival tissue from patients with acute necrotizing ulcerative gingivitis. Infect. Immun. 59:2653-2657. Riviere,G. R. 1991. Pathogen-relatedoral spirochetes from dental plaque are invasive. Infect. Immun. 59:3377-3380. Fohn, M. J. et al. 1988. Specificity of antibodies from patients with pinta for antigen of Treponema pallidum subspecies pallidum. J. Infect. Dis. 157:32-37.
Case Report
Nocardiafarcinica Susan E. Sharp, Ph.D. Maritza Lemes, MT (ASCP)
Microbiology Laboratory Department of Pathology and Laboratory Medicine Mount Sinai Medical Center Miami Beach, Florida 33140 A 40-yr-old flight attendant with HIV infection presented with suspected Pneumocystis carinii pneumonia (PCP). He was treated empirically with trimethopfim-sulfamethoxazole (TMPSMZ) and seemed to respond. Three weeks later he developed a rash, thought to he a drug reaction, and therapy was discontinued. One month later he developed night sweats, profuse diarrhea, and weight loss. Acid-fast smears of stool revealed Cryptosporidium sp. and he was treated with azithromycin, Four months later the patient was having significant abdominal pain with continuing diarrhea, and a peripheral line was placed to deliver total parenteral nutrition (TPb0 because he had lost 20% of his body weight. His bilirubin level and liver enzymes were beginning to Clinical IVficrobiology Newsletter 16:19,1994
rise and a liver biopsy was performed but it was not diagnostic. Within a month, the patient's liver function tests and bilirubin levels were still increasing and his diarrhea was worsening. A colonoscopic biopsy revealed CMV colitis and the patient was started on ganciclovir. The port established for TPN became infected and the patient developed line sepsis with Pseudomonas aeruginosa, which responded to treatment with an aminoglycoside, Improvement in the gastrointestinal symptomology was seen over the next 2 mo and his weight stabilized; however, his liver enzyme values continued to rise. Surgery was performed at this time to alleviate a biliary obstruction. On follow-up examination it was noticed that the patient had developed a tender lymph node in the fight inguinal area. A needle aspiration revealed many polymorphonuclear ieukocytes and numerous slender, gram-positive, headed, branching bacilli. The culture grew Nocardia sp. after 2 d of incubation on routine laboratory media and the patient was started on ceftriaxone. The patient did not improve on this treatment but © 1994 Elsevier Science Inc.
continued to have fever and drainage from the inguinal area. Susceptibility reports then showed that the organism was resistant to third generalion cephalospofins and his therapy was changed to minocycline and cipmfloxacin. The patient responded to this combination therapy and within days showed less drainage and tendcxness. This patient's organism showed two morphotypes---one that was glaborous and orange, and another that was white and chalky. They were originally identifled as N. asteroides based on negative results for xanthine, tyrosine, casein, and starch hydrolysis. Both strains were determined to be resistant to cefotaxime, ceftriaxone, ampicillin, erythromycin, kanamycin, tobramycin and gentamicin; intermediate to minocycline and imipenem; and susceptible to amikacin, sulfonamide, and ciprofloxacin. Additional biochemical tests further differentiated this species from N. asteroides in that it grew at 45°C within 3 d, utilized acetamide, and produced acid from rhamnose (N. asteroides is negative for the above tests). In retrospect, at initial presentation, 0196-4399D4/$0.00 + 0%00
151
Conclusion The high prevalence of animal bites in the United States clearly suggests that prevention could be improved. Educaring people about animal safety and the risks involved in approaching or
Emerg. Med. 9:79-83. Edwards, M. S. 1992. Infections due to human and animal bites, p. 2334-2338. In R. Feigin and J. Cherry (eds.) Textbook of pediatric infectious diseases, 3rd ed., volume II. 5. Wiley, J. F. 1990 Mammalian bites: review of evaluation and management. Clin. Pediatr. 29:283-287.
4.
keeping wild animals as pets is the first line of defense. When bites do occur, aggressive wound management, updating tetanus immune status, assessing rabies risk to provide immunoprophylaxis when necessary, and judicious use of empiric antibiotic therapy in high-risk situations remain standard care. Further evaluation of the clinical situations in which antimicrobial prophylaxis is warranted continues to be necessary. Until such time the recommendations provided here offer a reasonable approach
6.
Sacks, J. J., R. W. Sauin, and S.E. Bonzo. 1989. Dog bite-related fatalities from 1979 through 1988. JAMA 262:1489-1492. 8. McDonough, J. J., P. J. Stem, and J.W. Alexander. 1987. Management of anireal and human bites and resulting human infections. Curt. Clin. Top. Infect. Dis. 8:11-36. 9. Pinckney, L. E. and L. A. Kennedy. 1980. Fractures of the infant skull caused by animal bites. Am. J. Roentgenol. 135:179-180.
to this all too common problem. References 1. Baker, M. D. 1989. Bites and scratches
10. Centers for Disease Control. 1993. Human rabies---New York. Morbid. Mortal. Weekly Rep. 42:799-806.
when pets fight back. Contemporary Pediatr. 6:76-84. 2. Goldstein, E. J. 1989. Management of human and animal bite wounds. J. Am. Acad. Dermatol. 21:1275-1279. 3. Aghababian, R. V. and J. E. Conte Jr. 1980. Mammalian bite wounds. Ann.
11. Centers for Disease Control. 1991. Summary of notifiable diseases, United States. Morbid. Mortal. Weekly Rep. 40:53. 12. Houff, S. A. et al. 1979. Human-to human transmission of rabies virus by corneal transplant. N. Engl. J. Med. 300:603-604.
13. Committee on Infectious Diseases. 1991. Rabies, p. 391-398. In Report of the Committee on Infectious Diseases, 22rid ed. Elk Grove, IL. 14. Helmick, C. G. 1983. The epidemiology of human rabies post-exposure prophylaxis, 1980--1981. JAMA 250:1990. 15. Uhaa, I. J. et al. 1992 Benefits and costs of using an orally absorbed vaccine to control rabies in raccoons. J. Am. Vet. Med. Assoc 201:1873. 16. Callaham, M. 1980. Prophylactic antibiotics in common dog bite wounds: a controlled study. Ann. Emerg. Med. 9:410-414. 17. Elenbass, R. M., W. K. McNalmey, and W.A. Robinson. 1984. Evaluation of IXOphylactic oxacillin m cat bite wounds. Ann. Emerg. Med. 13:155-157. 18. Brook, I. 1987. Microbiology of human and animal bite wounds in children. Pediatr. InfecL Dis. J. 6:29-32. 19. Goldstein, E. J., D. M. Citron, and S. M. Finegold. 1984. Role of anaerobic bacteria in bite wound infections, Rev. Infect. Dis. 6 (Suppl. 1):s177-s183. 20. Feder, H. M., J. D. Shanley, and J. A. Barbara. 1987. Review of 59 patients hospitalized with animal bites. Pediatr. Infect. Dis. J. 6:24-28.
Editorial
Spirochetes in Periodontal Disease George R. Riviere, D.D.S., Ph.D. School of Dentistry, Oregon Health Sciences University, Portland, OR 97201-3097 The oral cavity is colonized by a great diversity of microorganisms, Most niches contain a stable indigenous microflora but teeth and their supporting tissues, collectively called the periodontium, represent the most dynamic microenvironment in the mouth. A variety of factors, including tooth morphology, diet, and oral hygiene, influence bacterial colonization and proliferation at these sites, In periodontal health, tooth surfaces immediately above the free gingival margin are coated predominantly by nonmotile, gram-positive cocci and
rods. Cleaned tooth surfaces are recolonized rapidly but as long as plaque accumulation is restricted, periodontal tissues tolerate the presence of the normal oral flora. Dental plaque is formed from accumulation of bacteria and incorporation of dietary substances and organic material from the host into the biomass. Buildup of supragingival plaque creates sequestered environments within plaque itself and within the gingival sulcus, the space between tooth and gum. These isolated niches support proliferation of anaerobic, gramnegative bacteria. If supmgingival plaque is controlled, subgingival plaque is tinlikely to form (1). If plaque is allowed to accumulate, the number and diversity of microorganisms increase rapidly, i
148
0196-4399/94/$0.00 + 07.00
Mature plaque may contain 1011 bacteria per gram, representing as many as 300 species (2-4). The presence of plaque, particularly subgingival plaque, is strongly associated with the etiology and pathogenesis of periodontal disease. It is not known whether this assoelation is a result of nonspecific effects of plaque components on periodontal tissues or whether disease is a result of the virulence of specific bacteria. Spirochetes are difficult to fmd in the oxygen-rich gingival sulci of people with healthy periodontal tissues. Colonization and proliferation of these anaerobic bacteria are further restricted by the paucity of plaque associated with periodontal health. Conversely, spirochetes often flourish in subgingival plaque at
Hi © 1994 Elsevier Science Inc.
Clinical Microbiology Newsletter 16:19,t994
sites of periodontal disease, and they are one of the types of bacteria in subgingival plaque that have the strongest association with deterioration of periodontal tissues (5). When appropriate techniques are employed for their detection, spirochetes are found to be among the predominant bacteria at diseased sites (6), at refractory treated sites, and at sites of recurrent disease (7). Unidentiffed spirochetes have been observed within connective tissue near lesions of necrotizing ulcerative gingivitis (8, 9), suggesting that at least some oral spirechetes may be invasive, Although oral spirochetes in plaque suspensions are easily identified with darldield or phase microscopy, they are difficult to isolate among the many faster growing and less fastidious competitors found in subgingival plaque. At the present time, five species of oral treponema have been isolated and propagated in pure culture--they are Treponema denticola, T. pectinovorum, T. scoliodontum, T. socranskii, and T. vincentii. These cultivable oral species represent only a ~rnallportion of the diverse spirochete morphotypes that have been observed in plaque samples (10). Most oral spirochetes have never been isolated or identified, and their pathogenic potential remains unknown, Treponema denticola is probably the most frequently isolated oral spirochete (11) and it is certainly the most studied of the oral treponema. T. denticola is probably an opportunistic organism. It is found in low numbers in plaque from children and young adults with healthy periodontal tissues (12) and it is one of the predominant bacteria in plaque assoelated with periodontal disease (13, 14). T. denticola is often found in association with Porphyromonas gingivalis (15), suggesting that infection by T. denticola may be dependent upon prior colonization by other bacteria. T. denticola expresses a variety of outer membrahe antigens (16, 17) and four serologic variants axe recognized (18, 19). T. denticola strains proved to be identical based on 16S rRNA sequence analysis and they have been positioned in a phylogenetic tree next to the host-indigenous, nonpathogenic T. phagedenis (20). T. denticola has several characteristics that suggest pathogenic potenClinical Microbiology Newsletter 16:19,1994
tial. For example, T. denticola possesses proteolytic enzyr ~es that could contribute to tissue deg~~dation (21, 22), and trypsin-like enzy ~e activity of T. denticola correlates w ell with periodontal disease and the e ffectiveness of treatment (23). T. det ticola, but not T. vincentii, suppresse: fibroblast proliferation in vitro (24) and lymphocyte responses tO mitogens (25) by inhibiting DNA, RNA, and protein synthesis in a dose.dependent manner. T. denticola has gly~oproteins that mediate erythrocyte agglutination (26, 27), and it attaches to human, rat, and guinea pig cells in vitro (28, 29). Under some conditions, anaehment can damage epithelial cells in culture (30). However, T. deno'cola, T. scoliodontum, and T. vincentii do not attach to rabbit fibroblasts (31), indicaring that attachment potential of oral spirochetes may be limited compared with the pathogen T. pallidum (31). People with healthy periodontal tissues and patientsl with various periodontal diseases have similar levels of serum antibodies to 7". denticola, 1". vincentii, and T. socranskii (32, 33). It has been reported that antibody levels to many plaque bacteria, including T. vincentii, decline following treatment, but antibodies to T. denticola persist at pretreatment levels (34). Maintenance of antibody levels after periodontal therapy, which always includes plaque removal, suggests either that debridement did not eradicate!antigen, or that T. denticola antibodies were maintained by similar bacteria at other sites. The importance of serum antibodies to oral spirochetes is difficult to assess because serum contains antibodies to virtually all plaqOe microorganisms. Furthermore, thelplethora of common and cross-reacting bacterial antigens makes interpretation of serologic assays difficult when whole cells or crude antigens are used to ¢letectpolymorphic, polyclonal serum antibodies, It is also diffigult to determine whether certain qharacteristics of oral spirochetes relate to virulence. For example, the ability to adhere to surfaces or to other microorganisms is a characteristic common ~o all oral bacteria, Adherence is neCessary to resist displacement by th~ flow of saliva and by the mechanical debridement of mastica© 1994 Elsevier Science Inc.
tion. Since T. denticola and other oral treponema are found in the presence of healthy periodontal tissues, tissue breakdown is not an inevitable consequence of their ability to adhere to epithelial cells or of their ability to produce extracellular ptoteolytic enzymes. One should also use caution when evaluating the meaning of relative numbers of bacteria in plaque. Proliferation of spirochetes and other bacteria at diseased sites is I m ~ b l y a reflection of the supportive natme of the environment rather than an indication of pathogenicity. Another approach to studying the oral spirochetes has been to determine whether any of them have distinguishing characteristics in common with known pathogens. For example, although T. pallidum expresses cross-reacting antigenic determinants (35, 36), pathogenic treponema also share unique antigens not found on nonpathogenic spirochetes (37, 38). Monoclonal antibodies to antigens located on 47-, 37-, 14-, and 12-kDa molecules (39, 40) serve to distinguish T. pallidum subspecies (41) from host-indigenous, nonpathogenic spirochetes. Plaque from people with healthy periodontal tissues did not contain spirechetes that react with T. pallidum monoclonal antibodies (18). However, pathogen-related oral spirochetes (PROS) were found in plaque from patients with acute necrotizing ulcerative gingivitis, from patients with chronic adult periodontitis (42, 43), and from HIV-infected subjects with periodontal disease (44). T. pallidum monoclonal antibodies detected PROS antigen in connective tissue around necrotic gingiva (45). T. denticola monoclonal antibodies also detected antigen near gingival lesions (45). However, PROS were the only plaque microorganisms able to invade living tissue in an in vitro assay (46). No cultivable oral spirochete, including T. denticola, proved to be invasive under these experimental conditions. In the manner that infection with T. carateum induces serum antibodies against pathogen-restricted antigens of T. pallidum (47), serum from PROS-infected subjects reacted with 47-, 37-, 14-, and 12-kDa molecules from T. pallidum in immunoblot assays (42). These sera were unreactive in VDRL and FTA0196-4399~t4/$0.00 + 07.00
149
ABS tests. People with healthy periodontal tissues did not have serum anti-
bodies that reacted with pathogenrestricted determinants from T. palh'dum (42). Reactivity with T. pallidum mono-
clonal antibodies does not mean that
PROS are pathogens. The ability to invade tissue does not mean that PROS cause any form o f periodontal disease. More studies are needed before PROS can be f'Lrmlyassociated with the etiology and/or pathogenesis o f periodontal disease. Further characterization o f PROS is difficult because they resist isolation and cultivation. Traditional approaches that have been used to isolate other oral spirochetes have not produced a pure culture o f any PROS. PROS may prove to be more host-dependent than other oral spirochetes and may be as difficult to grow in vilro as T. pallidum. In conclusion, oral spirochetes occupy an intriguing but enigmatic position among the hundreds of bacteria found in plaque. The well-established, strong positive correlation of spirochetes with periodontal deterioration suggests that some oral spirochetes may be important in the etiology and/or pathogenesis o f periodontal disease. More effort is needed to isolate and
identify oral spirochetes, and more research is needed to define the pathogenic potential of new isolates, References 1.
Katsanoulas, T., I. Renee, and R. Attstrom. 1992. The effect of supragingival plaque control on the composition of subgingival flora in periodontal pockets. J. Ciin. Periodontol. 19:760-765. 2. Harwood, C. S. and E. Canale-Parola. 1984. Ecology of spirochetes. Ann. Rev. Microbiol. 38:161-192. 3. Newman, H. N. 1984. Plaque and chronic inflammatory disease. A question of ecology. J. Clin. Periodontol. 7:533--541. 4. Newman, M. G. 1984. Anaerobic oral and dental infection. Rev. Infect. Dis. 6:107-114. 5. Loesche, W. J. 1993. Bacterial mediators in periodontal disease. Clin. Infect. Dis. $203-$210. 6. Loesche, W. J. et al. 1992. Comparison of various detection methods for periodontopathic bacteria: can culture be considered the primary reference standard? J. Clin. Microbiol. 30:418--426. 150
0196-4399/94/$0.00 + 07.00
7.
Listgarten, M. A., L. Chem-Hsiung, and V. Young. 1993. Microbial composition and pattern periodontitis. J. Periodontoi. 64:155-161. 8. Listgarten, M. A. and D. W. Lewis. 1967. The distribution of spirochetes in the lesion of acute necrotizing ulcerative gingivitis: an electron microscopic and statistical survey. J. Periodontol. 38:379-386. 9. Courtois, G. J. Ill, C. M. Cobb, and W. J. Killoy. 1983. Acute necrotizing ulcerative gingivitis. A transmission dectron microscope study. J. Periodontol. 54:671-679. 10. Loesche, W. J. 1988. The role of spirochetes in periodontal disease. Adv. Dent. Res. 2:275-283. 11. Chart, E. C. et al. 1993. Treponema denticola (ex Brumpt 1925) sp. nov., nom. rev., and identification of new spirochete isolates from periodontal pockets. Int. J. Syst. Bacteriol. 43:196-203. 12. Barron, S. L. et al. 1991. Use of monoclonal antibodies to enumerate spirochetes and identify Treponema denticola in dental plaque of children, adolescents and young adults. Oral Microbiol. Immunol. 6:97-101. 13. Simonson, L. G. et al. 1988. Quantitative relationship of Treponema denticola to severity of periodontal disease. Infect. Immun. 56:726-728 14. Riviere, G. R. et al. 1992. Relative proportions of pathogen-related oral spirochetes (PROS) and Treponema denticola in supragingival and subgingival plaque from patients with periodontitis. J. Periodontol. 63:131-136. 15. Simonson, L. G. et al. 1992. Bacterial synergy of Treponema denticola and Porphyromonas gingivalis in a multinational population. Oral Microbiol. Immunol. 7:111-112. 16. Yotis, W. W. et al. 1991. Biochemical properties of the outer membrane of Treponema denticola. J. Clin. Microbiol. 29:1397-1406. 17. Tall, B. D. and R. K. Nauman. 1994. Outer membrane antigens of oral treponema species. J. Med. Mierobiol. 40:62-69. 18. Keams, E. A. et al. 1991. Characterization of monoclonal antibodies to two Treponema denticola serotypes by the indirect fluorescent antibody assay, Microbios 65:14%153. 19. Simonson, L., H. Morton, and R. Schutt. 1989. Treponema denticola serotypes and solubilization of type-specific antigen. J. Dent. Res. 68:357 © 1994ElsevierScienceInc.
(Abstract 1401). 20. Paster, B. J. et al. 1991. Phylogenet~c analysis of the spirochetes. J. Bacteriol. 173:6101-6109. 21. Grenier, D., V.-J. Uitto, and B. C. McBride. 1990. Cellular location of a Treponema denticola chymotrypsinlike protease--importance of the protease in migration through the basement membrane. Infect. Immun. 58:347-351. 22. Loesche, W. J. et al. 1990. Development of a diagnostic test for anaerobic periodontal infections based on plaque hydrolysis of benzoyl-DL-argininenaphthylamide. J. Clin. Microbiol. 28:1551-1559. 23. 1.x~sche, W. J., J. Giordano, and P. P. Hujoel. 1990. The utility of the BAHIA test for monitoring anaerobic infection due to spirochetes (Treponema denticola) in periodontal disease. J. Dent. Res. 69:1696-1702. 24. Boehringer, H., N. S. Taichman, and B. I. Shenker. 1984. Suppression of fibroblast proliferation by oral spirochetes. Infect. Inunun. 45:155-159. 25. Shenker, B. J., M. A. Listgarten, and N. S. Taichman. 1984. Suppression of human lymphocyte responses by oral spirochetes: a monocyte-dependent phenomenon. J. lmmunol. 132:2039-2045. 26. Grenier, D. 1991. Characteristics of hemolytic and hemagglutinating activities of Treponema denticola. Oral Microbiol. Immunol. 6:246-249. 27. Mikx, F. H. M. and R. A. C. Kenlers. 1992. Hemagglutination activity of Treponema denticola grown in serum-free medium in continuous culture. Infect. Immun. 60:1761-1766. 28. Olsen, I. 1984. Attachment of Treponema denticola to cultured human epithelial cells. Scand. L Dent. Res. 92:55-63. 29. Keulers, R.A. et al. 1993. Attachment of Treponeraa denticola strains to monolayers of epithelial cells of different origin. Oral Microbiol. Immunol. 8:84-88. 30. Reijntjens F. M. et al. 1986. Adherence of oral treponemes and their effect on morphological damage and detachment of epithelial cells in vitro. Infect. Iramun. 51:642---647. 31. Fitzgerald, T. J. et al. 1977. Characterization of the attachment of Treponema pallida~n (Nichols strain) to cultured mammalian cells and the potential relationship of attachment to pathogenicity. Infect. Immun. I8:467--478. 32. Tew, J. G. et al, 1985. Serum antibodies ClinicalMicrobiologyNewsletter16:19,1994
33.
34.
35.
36.
37.
in young adult humans reactive with periodontitis associated treponemes. L Pcriodont. Res. 20:.580-590. Lai, C.-H. et al. 1986. Serum IgA and IgG antibodies to Treponemavincentii and Treponema denticola in adult periodontitis, juvenile periodontitis and periodontally healthy subjects. J. Clin. Periodontol. 13:752-757. Awkhil, I. et al. 1988. The effects of periodontal therapy on serum antibody (IgG) levds to plaque microorganisms. J. Clin. Periodontal. 15:544-550. Hanff, P. A., L N. Miller, and M.A. LoveR. 1983. Molecular characterization of common treponemal antigens. Infect. Immun. 40:825-828. Wos, S. M. and K. Wicher. 1986. Extensire cross-reactivity between Treponema pallidum and cultivable lreponemas demonstrated by sequential immunoabsorption. Int. Archs. Appl. Allergy Immunol. 79:282-285. Baker-Zander, S.A. and S.A. Lukehart. 1983. Molecular basis of immunologi-
38.
39.
40.
41.
42.
cal crossreacfivity between Treponema pallidum and Treponemapertenue. Infect. Immun. 42:634--638. Bakcr-Zander,S. A. and S. A. Lakehart. 1984. Antigeniccross-reactivitybetween Treponema pallidum and otherpathogenic members of the family Spirechaetaceae.Infect. Immun. 46:116-121. Lukehart, S. A. et al. 1985. Characterization of monoclonal antibodies to Treponemapallidum. J. lmmunol. 134:585-592. Marchitto, K. S., C. K. SeUandGrossling, and M. V. Norgard. 1986. Molecular specificities of monoclonal antibodies directed against virulent Treponema pallidum. Infect. Immun. 51:168-176. Marchitto, K. S. et al. 1984. Monoclonal antibody analysis of specific antigenic similarities among pathogenic Treponemapallidum subspecies. Infect. Immun. 45:660-666. Riviere, G. R. et al. 1991. Identification of spirochetes related to Treponemapal-
43.
44.
45.
46.
47.
lidam in necrotiz~ ulcerative gingivitis and chronic periodontitis. N. Engl. J. Med 325:539-543. Riviere, G. R. et al. 1992. Relative proportions of pathogen-related oral spirochetes (PROS) and Treponema denticola in supragingival and subgingival plaque from patients with periodontitis. J. Periodontol. 63:131-136. Rosenstein, D. I., G. R. Riviere, and K. S. Elott. 1994. HIV-associated periodontal disease: new oral spirochete found. J. Am. Dent. Assoc. 124:76-80. Riviere, G. R. et al. 1991. pathogen-related spirochetes identified within 8ingival tissue from patients with acute necrotizing ulcerative gingivitis. Infect. Immun. 59:2653-2657. Riviere,G. R. 1991. Pathogen-relatedoral spirochetes from dental plaque are invasive. Infect. Immun. 59:3377-3380. Fohn, M. J. et al. 1988. Specificity of antibodies from patients with pinta for antigen of Treponema pallidum subspecies pallidum. J. Infect. Dis. 157:32-37.
Case Report
Nocardiafarcinica Susan E. Sharp, Ph.D. Maritza Lemes, MT (ASCP)
Microbiology Laboratory Department of Pathology and Laboratory Medicine Mount Sinai Medical Center Miami Beach, Florida 33140 A 40-yr-old flight attendant with HIV infection presented with suspected Pneumocystis carinii pneumonia (PCP). He was treated empirically with trimethopfim-sulfamethoxazole (TMPSMZ) and seemed to respond. Three weeks later he developed a rash, thought to he a drug reaction, and therapy was discontinued. One month later he developed night sweats, profuse diarrhea, and weight loss. Acid-fast smears of stool revealed Cryptosporidium sp. and he was treated with azithromycin, Four months later the patient was having significant abdominal pain with continuing diarrhea, and a peripheral line was placed to deliver total parenteral nutrition (TPb0 because he had lost 20% of his body weight. His bilirubin level and liver enzymes were beginning to Clinical IVficrobiology Newsletter 16:19,1994
rise and a liver biopsy was performed but it was not diagnostic. Within a month, the patient's liver function tests and bilirubin levels were still increasing and his diarrhea was worsening. A colonoscopic biopsy revealed CMV colitis and the patient was started on ganciclovir. The port established for TPN became infected and the patient developed line sepsis with Pseudomonas aeruginosa, which responded to treatment with an aminoglycoside, Improvement in the gastrointestinal symptomology was seen over the next 2 mo and his weight stabilized; however, his liver enzyme values continued to rise. Surgery was performed at this time to alleviate a biliary obstruction. On follow-up examination it was noticed that the patient had developed a tender lymph node in the fight inguinal area. A needle aspiration revealed many polymorphonuclear ieukocytes and numerous slender, gram-positive, headed, branching bacilli. The culture grew Nocardia sp. after 2 d of incubation on routine laboratory media and the patient was started on ceftriaxone. The patient did not improve on this treatment but © 1994 Elsevier Science Inc.
continued to have fever and drainage from the inguinal area. Susceptibility reports then showed that the organism was resistant to third generalion cephalospofins and his therapy was changed to minocycline and cipmfloxacin. The patient responded to this combination therapy and within days showed less drainage and tendcxness. This patient's organism showed two morphotypes---one that was glaborous and orange, and another that was white and chalky. They were originally identifled as N. asteroides based on negative results for xanthine, tyrosine, casein, and starch hydrolysis. Both strains were determined to be resistant to cefotaxime, ceftriaxone, ampicillin, erythromycin, kanamycin, tobramycin and gentamicin; intermediate to minocycline and imipenem; and susceptible to amikacin, sulfonamide, and ciprofloxacin. Additional biochemical tests further differentiated this species from N. asteroides in that it grew at 45°C within 3 d, utilized acetamide, and produced acid from rhamnose (N. asteroides is negative for the above tests). In retrospect, at initial presentation, 0196-4399D4/$0.00 + 0%00
151