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Epidemiologic Notes and Reports Plasmid-Mediated Tetracycline- Resistant Neisseria gonorrhoeae -- Georgia, Massachusetts, Oregon

CDC has confirmed 79 cases of plasmid-mediated tetracycline-resistant Neisseria gonorrhoeae infection (TRNG) between February 1985, when it was first identified, and March 14, 1986. Three of the 79 cases, all from Massachusetts, have been confirmed as combined tetracycline-resistant penicillinase-producing N. gonorrhoeae (TRNG-PPNG). Sixty-five (82%) of the confirmed TRNG cases were isolated from three states--Georgia (31 cases), Massachusetts (23), and Oregon (10). The Georgia and Massachusetts cases were identified as a result of a collaborative surveillance with CDC. Georgia's Fulton and DeKalb County health departments (metropolitan Atlanta) conducted active TRNG surveillance in the fall of 1985. Massachusetts has an ongoing statewide surveillance program for gonococcal resistance. The Oregon cases are all from an outbreak among homosexual men in the Portland area, and a brief report follows.

On October 22, 1985, a 32-year-old homosexual male presented to the sexually transmitted disease (STD) clinic in Multnomah County, Oregon, with a 3-day history of urethral discharge and dysuria. A diagnosis of gonorrhea was made, and because the patient was allergic to penicillin, oral tetracycline was prescribed. On returning to the clinic 1 week later, the patient was still symptomatic and had a positive urethral culture for N. gonorrhoeae. Sensitivity testing by disk diffusion demonstrated a zone size to tetracycline of 13 mm (sensitive strains were defined as having disk diffusion zone sizes greater than 30 mm). The isolate was confirmed by CDC as high-level TRNG with a minimum inhibitory concentration of 32 ug/ml.

Between October 22, and December 26, 1985, nine other CDC-confirmed TRNG cases were identified at the Multnomah County STD clinic on the basis of disk-diffusion testing results. All patients were homosexual males infected at rectal (three patients), urethral (two), rectal and urethral (four), and pharyngeal (one) sites. All four patients treated with tetracycline alone were treatment failures, and one of these had developed clinical orchitis since his initial clinic visit. All cases were of the same auxotype and serovar class, suggesting the isolates were of a clonal origin. Six additional cases of gonococcal disease, including two out-of-state cases, were diagnosed by contact-tracing. Two cases were tetracycline treatment failures; two were TRNG on the basis of disk-diffusion testing (zone size less than 20 mm); and two were not tested. Nineteen contacts, including 15 bathhouse contacts of one patient, could not be traced due to lack of adequate identifying and locating information.

In response to this outbreak, the Multnomah County Health Department instituted ceftriaxone as the drug of choice for all gonococcal infections among homosexual males. Educational efforts targeted at both the professional and lay community were intensified toward increasing TRNG awareness. Reported by B Carlson, F Myers, L Mofenson, H George, Massachusetts State Laboratory Institute, G Grady, MD, State Epidemiologist, Massachusetts Dept of Public Health; RW Hill, CP Schade, J Kolden, J Mitchell, G Sawyer, M Ware, V Fox, J Karius, H Horton, Multnomah County Dept of Human Svcs; R Poole, R Miller, R Blumberg, DeKalb County Board of Health, Decatur, Georgia; Sexually Transmitted Disease Laboratory Program, Center for Infectious Diseases, Epidemiology Research Br, Div of Sexually Transmitted Diseases, Center for Prevention Svcs, CDC.

Editorial Note

Editorial Note: The geographic dispersion of TRNG strains since the original MMWR report in September 1985 (1) has been impressive. The rapid onset of the outbreak in Portland and the large number of untraceable contacts elicited from several of the patients underscore the potential for rapid dissemination of new gonococcal strains into a community.

The identification of combined PPNG-TRNG strains in Massachusetts once again demonstrates the ability of N. gonorrhoeae to acquire multiple drug-resistant determinants. This includes such combinations as plasmid-mediated resistance (e.g., PPNG-TRNG), plasmid and chromosomally-mediated resistance (e.g., spectinomycin-resistant PPNG) (2,3), or chromosomally-mediated resistance to multiple antibiotics (4).

The largest numbers of TRNG cases were described from areas where active surveillance programs were in operation. With the exception of testing for B-lactamase, most areas in the United States do not routinely perform antimicrobial susceptibility testing on gonococcal isolates. Therefore, the incidence of resistant strains that do not present as treatment failures is not known.

Tetracycline (doxycycline, minocycline) therapy alone is not recommended for the treatment of gonococcal infections (5). Because of the increasing geographic distribution and the complexity of antimicrobial resistance in N. gonorrhoeae and the increasing need for effective surveillance for new cases, CDC is preparing comprehensive guidelines for susceptibility testing.


  1. CDC. Tetracycline-resistant Neisseria gonorrhoeae--Georgia, Pennsylvania, New Hampshire. MMWR 1985;34:563-4, 569-70.

  2. Ashford WA, Potts DW, Adams HJU, et al. Spectinomycin-resistant penicillinase-producing Neisseria gonorrhoeae. Lancet 1981;II:1035-7.

  3. Piziak MV, Woodbury C, Berliner D, et al. Resistance trends of Neisseria gonorrhoeae in the Republic of Korea. Antimicrob Agents Chemother 1984;25:7-9.

  4. Rice RJ, Biddle JW, JeanLouis YA, DeWitt WE, Blount JH, Morse SA. Chromosomally mediated resistance in Neisseria gonorrhoeae in the United States: results of surveillance and reporting 1983-1984. J Infect Dis 1986;153:340-5.

  5. CDC. 1985 STD treatment guidelines. MMWR 1985;34(suppl 4S):75S-108S.

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