Typing of Neisseria gonorrhoeae isolates by phenotypic and genotypic techniques in New Delhi, India.

BACKGROUND

The objective of this study is to investigate gonococcal isolates using phenotypic and genotypic methods.

METHODOLOGY: Sixty gonococcal isolates obtained were examined. Strains were divided into 9 resistant phenotypes: Chromosomally mediated penicillin-resistant Neisseria gonorrhoeae (CMRNGP), penicillinase-producing NG (PPNG), chromosomally mediated tetracycline-resistant NG (CMRNGT), TRNG, PPNG and TRNG, CMRNGPT, quinolone resistant NG (QRNG), Azithro R, and decreased susceptibility (DS) to ceftriaxone. These isolates were also subjected to auxotyping and NG-multi-antigen sequence typing (MAST).

RESULTS

Of 60 isolates, 32 (53.33%) PPNG and only one was CMRNGP; 16 (26.66%) were CMRNGT, while 18 (30%) were TRNG. Both PPNG and TRNG found in 13 (21.66%) and none were CMRNGPT. QRNG was seen in 93.33%, 5% Azithromycin R, and 6.66% were DS to ceftriaxone. Based on auxotyping, 24 (40%) nonrequiring, 16 (26.66%) were proline requiring, 13 (21.66%) arginine requiring while 7 (11.66%) belonged to others. The most common ST was 6058 (32.5%). The discriminatory indices of antibiogram, auxotyping and NG-MAST were 0.77, 0.72, and 0.95, respectively.

CONCLUSIONS

NG-MAST is the method of choice for epidemiological studies.