TETRACYCLINE-RESISTANT NEISSERIA-GONORRHOEAE - CHARACTERISTICS OF PATIENTS AND ISOLATES AT A LONDON GENITOURINARY MEDICINE CLINIC

Objectives: To compare auxotypes, serovars, and antibiograms of tetrac ycline-resistant Neisseria gonorrhoeae (TRNG) and non-TRNG isolated fr om patients attending an East London Genitourinary Medicine (GUM) Clin ic. To obtain plasmid profiles for penicillinase-producing gonococci ( PPNG) as well as presumptive TRNG. To identify differences in patient characteristics for the TRNG and non-TRNG patient groups. Study Design : Gonococcal isolates were collected from 400 patients attending the G UM clinic at the Royal London Hospital GUM Clinic over a 1-year period . Isolates (378) were tested for susceptibility to various antibiotics , auxotyped, and serotyped. Plasmid profiles were obtained for PPNG an d isolates exhibiting high-level tetracycline resistance (TRNG). The p resence of the tet M determinant was confirmed using the polymerase ch ain reaction (PCR). The PCR product was digested with the restriction endonuclease (RE) Hpa II and electrophoresed on a 2.5% agarose gel to determine an ''RE pattern.'' Patient data were collected by retrospect ive case-note review. Results: TRNG (n = 42) accounted for 11% of the 378 isolates tested, and the remaining 336 (89%) isolates were non-TRN G. Non-requiring auxotrophy and P1B-2 serovar expression occurred more frequently among TRNG. PPNG accounted for 31% of TRNG and 5% of non-T RNG. Chromosomal resistance to penicillin (CMRNG) was absent among TRN G but accounted for 11% of non-TRNG. One TRNG isolate showed decreased susceptibility to ciprofloxacin (MIC 0.25 mg/l). All isolates were se nsitive to cefotaxime, cefixime, spectinomycin, and azithromycin. All TRNG possessed the 25.2 MDa plasmid and produced a PCR product of appr opriate size after tet M gene sequence amplification. RE digests of th e PCR product gave a single pattern. None of the TRNG in contrast to 1 8% of the non-TRNG mere acquired homosexually. Ethnic distribution dif fered between the patients with TRNG and patients without non-TRNG (Af ro-Caribbean 81% versus 58%; white 19% versus 36%). Most TRNG were acq uired in the United Kingdom. Conclusions: TRNG differ from the non-TRN G in their auxotype and serovar distribution. PPNG are more common amo ng the TRNG isolates, whereas CMRNG appear absent. TRNG are isolated m ore commonly from Afro-Caribbean patients and were not represented amo ng homosexually acquired isolates.