Molecular epidemiology of Mycobacterium avium complex isolated from patients with and without AIDS in Brazil and England.

Mycobacterium avium complex (MAC) is ubiquitous throughout the world. It is an opportunistic pathogen in AIDS patients but the number of cases in HIV negative patients is also increasing. The aim of this study was to determine whether patients were being infected with different MAC strains or whether one strain was dominant. DNA obtained from isolates in Brazil and England were compared using pulsed field gel electrophoresis (PFGE). Strains from 22 Brazilian patients clustered into 7 groups but 68/90 patients had a unique strain. In all patients, Brazilian and English, the same strain was isolated repeatedly over time, some over several years. This study shows that it is most likely that Man is infected from the environment and that one strain can survive without change for many years both in the environment and in Man.

Gonorrhoea in inner London: the hidden epidemic

BACKGROUND: Very little is known about local variations in the distribution of sexually transmitted infections in Great Britain. In the United States of America, rates of gonorrhoea are approximately ten times higher amongst African-Americans than whites. This study was designed to estimate population-based incidence rates of gonorrhoea in an inner London area and to examine their relationship with age, ethnic group and socioeconomic deprivation. DESIGN: Cross-sectional study. SETTING: Eleven Departments of Genitourinary Medicine in South and Central London. SUBJECTS: 1,978 first episodes of gonorrhoea diagnosed in 1994 and 1995 in residents of 73 electoral wards in the boroughs of Lambeth Southwark and Lewisham who attended any of the Departments of Genitourinary Medicine. MAIN OUTCOME MEASURES: Age-, sex- and ethnic-specific rates of gonorrhoea per 100,000 population aged 15 - 59 years per year. Rate ratios (95 percent confidence intervals) for the effects of age and ethnic group on gonorrhoea rates on women and men, before and after adjustment for confounding factors. RESULTS: Overall incidence rates of gonorrhoea in residents of Lambeth, Southwark and Lewisham were 138.3 per 100,000 per year for women and 291.9 per 100,000 per year for men aged 15-59 years. Inconsistencies in the coding of ethnicity, race, or nationality between Departments meant that cases in those from all black minority ethnic groups had to be considered in a single category. At all ages gonorrhoea rates were higher in members of black than white ethnic groups. After taking deprivation score and age into account women from black minority groups were 10.5 (8.6 - 12.8) times as likely and men 11.0 (9.7 - 12.6) times as likely as whites to experience gonorrhoea. Rate ratios for the effect of age, adjusted for ethnic group and privilege, were 15.2 (11.6 - 19.7) for women and 2.0 (1.7 - 2.5) for men aged 15 -19 years compared to those over 30 years. CONCLUSIONS: Gonorrhoea rates on Lambeth, Southwark and Lewisham in 1994-95 were six to seven times higher than for England and Wales one year earlier. The presentation of national trends thus hides the disproportionate contribution of ongoing endemic transmission in this area. Teenage women and young adult men, particularly those from black minority ethnic groups were the most heavily affected, even after socioeconomic underprivilege is taken into account. (AU)

Sexual mixing patterns of patients with Gonorrhoea: is there a core group?

BACKGROUND: Epidemics of sexually transmitted infections are maintained by high level transmission amongst `core groups' of individuals, raising the basic reproductive rate to greater than unity. Assortative sexual mixing, that is, choosing partners who are like, rather than unlike, with respect to certain characteristics contributes to the persistent infection with a core group. We have reported high rates of gonorrhoea amongst people from black minority ethnic groups residing in Lambeth, Southwark and Lewisham. OBJECTIVES: To examine assortiveness of sexual mixing according to demographic characteristics of patients with heterosexually acquired gonorrohoea. SETTING: The Caldecot Centre, Department of Genitourinary Medicine, King's Healthcare. SUBJECTS: 287 heterosexual clinic attendees participating in contact tracing interviews for microscopy or culture proven gonorrhoea from 06/03/95 to 12/01/96 MAIN OUTCOME MEASURES: Matrices formed by cross-tabulation of ethnicity, residence and social class of gonorrhoea index cases and their most recent sexual partner. Assortativeness measured by Q1, a value ranging from zero (random mixing) to one (completely assortative). RESULTS: there were 120 (42 percent) female and 167 male respondents. 67 percent of female cases and 74 percent of male cases were of self-reported black Caribbean ethnicity. 48 percent of relationships with the most recent partner were temporarily concurrent with another partnership (48 percent of black cases versus 29 percent of white cases, p=0.19). Values of Q in women and men, respectively were: ethnicity, 0.64 and 0.60: borough of residence, 0.56 and 0.53; social class, 0.39 and 0.35; age group 0.37 and 0.47. CONCLUSIONS: Concurrency of sexual partnerships is common in individuals with gonorrhoea with a trend towards increased concurrency amongst those from black ethnic groups. Assortativeness in the selection of sexual partners is most evident for ethnic group and geographic area. These factors may contribute to the disproportionate number of individuals of black Caribbean ethnicity with gonorrhoea in South East London. Further work is required to examine the attitudes and practices with members of different ethnic groups with respect to sexual relationships and behaviours. Culturally appropriate interventions to reduce the burden of sexually transmitted infections should be targeted to high risk geographic areas.(AU)