An epidemiological evaluation of the use of microbiological tools for identifying gonorrhoea infection networks

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.

Partner Notification for Sexually Transmitted Diseases

Partner notification, a principal means of controlling sexually transmitted diseases, has traditionally been performed by public health professionals. They interview infected persons and contact the sex partners of these persons to notify them and convince them of the need to seek evaluation and treatment (known as "provider referral"). This notification method is labor intensive; the typical alternative to provider referral is to leave notification to the infected person (known as "patient referral"). However, innovations in partner notification, often created by public health professionals responsible for the practice, have yielded adjuncts and complements to both provider and patient referral. The present review article covers 4 areas of innovation: (1) enhancements to patient referral instructions and provider interview techniques, (2) use of the Internet in partner notification, (3) the emerging influence of network methods, and (4) expedited partner therapy, principally through patient-delivered medications or prescriptions. Partner notification remains necessary, and flexibility, openness to the use of multiple methods, and collaboration are likely to be helpful.

Sexual networks and sexually transmitted infections: a tale of two cities

Research on risk behaviors for sexually transmitted infections (STIs) has revealed that they seldom correspond with actual risk of infection. Core groups of people with high-risk behavior who form networks of people linked by sexual contact are essential for STI transmission, but have been overlooked in epidemiological studies. Social network analysis, a subdiscipline of sociology, provides both the methods and analytical techniques to describe and illustrate the effects of sexual networks on STI transmission. Sexual networks of people from Colorado Springs, Colorado, and from Winnipeg, Manitoba, Canada, infected with chlamydia during a 6-month period were compared. In Winnipeg, 442 networks were identified, comprising 571 cases and 663 contacts, ranging in size from 2 to 20 individuals; Colorado Springs data yielded 401 networks, comprising 468 cases and 700 contacts, ranging in size from 2 to 12 individuals. Taking differing partner notification methods and the slightly smaller population size in Colorado Springs into account, the networks from both places were similar in both size and structure. These smaller, sparsely linked networks, peripheral to the core, may form the mechanism by which chlamydia can remain endemic, in contrast with larger, more densely connected networks, closer to the core, which are associated with steep rises in incidence.