Genotypic and demographic characterization of invasive isolates of Salmonella Typhimurium in HIV co-infected patients in South Africa.

BACKGROUND: Non-typhoidal Salmonella are frequently food-borne zoonotic pathogens that may cause invasive disease in HIV-positive individuals. METHODOLOGY: Invasive isolates (n = 652) of Salmonella Typhimurium from human patients in Gauteng Province of South Africa were investigated for the years 2006 and 2007. Bacteria were identified using standard microbiological techniques and serotyping was performed using commercially available antisera. Susceptibility testing to antimicrobial agents was determined by the E-test. Genotypic relatedness of isolates was investigated by pulsed-field gel electrophoresis analysis of digested genomic DNA. RESULTS: Forty-five clusters of isolates were identified, of which four (clusters 3, 5, 6 and 11) were major clusters. Most isolates originated from hospital H2 and most were isolated from patients in the age range of 15 to 64 years. Ninety-three percent (213/230) of patients with a known HIV status were HIV-positive. Most isolates showed resistance to multiple antibiotics. The most commonly expressed antibiotic resistance profiles were ACSSuNa (14%; 75/555) and ACSSuTNa (13%; 72/555). Some evidence was found for nosocomial acquisition of isolates. Of the isolates from the major clusters 3, 5, 6, and 11, 33% (8/24), 6% (7/117), 4% (1/26) and 6% (3/52) were of nosocomial origin, respectively. CONCLUSIONS: In South Africa, Salmonella Typhimurium remains a major opportunistic infection of predominantly HIV-positive patients. Clonally diverse strains that are resistant to multiple antibiotics may circulate in patients aged between 15 and 64 years over prolonged periods within the hospital environment, adding to the health care burden.

Population-based surveillance for cryptococcosis in an antiretroviral-naive South African province with a high HIV seroprevalence.

OBJECTIVES: To measure the burden of disease and describe the epidemiology of cryptococcosis in Gauteng Province, South Africa. DESIGN AND METHODS: The study was an active, prospective, laboratory-based, population-based surveillance. An incident case of cryptococcosis was defined as the first isolation by culture of any Cryptococcus species from any clinical specimen, a positive India ink cryptococcal latex agglutination test or a positive histopathology specimen from a Gauteng resident. Cases were identified prospectively at all laboratories in Gauteng. Case report forms were completed using medical record review and patient interview where possible. RESULTS: Between 1 March 2002 and 29 February 2004, 2753 incident cases were identified. The overall incidence rate was 15.6/100 000. Among HIV-infected persons, the rate was 95/100 000, and among persons living with AIDS 14/1000. Males and children under 15 years accounted for 49 and 0.9% of cases, respectively. The median age was 34 years (range, 1 month-74 years). Almost all cases (97%) presented with meningitis. Antifungal therapy was given to 2460 (89%) cases of which 72% received fluconazole only. In-hospital mortality was 27% (749 cases). Recurrences occurred in 263 (9.5%) incident cases. Factors associated with death included altered mental status, coma or wasting; factors associated with survival included employment in the mining industry, visual changes or headache on presentation. CONCLUSIONS: This study demonstrates the high disease burden due to cryptococcosis in an antiretroviral-naive South African population and emphasizes the need to improve early recognition, diagnosis and treatment of the condition.

Gender as a risk factor for both antibiotic resistance and infection with pediatric serogroups/serotypes, in HIV-infected and -uninfected adults with pneumococcal bacteremia.

Among 1022 adults with either pneumococcal bacteremia or meningitis, 85.5% of women and 74.7% of men were infected with human immunodeficiency virus (HIV). A multivariable regression analysis found more pediatric serogroups/serotypes (odds ratio [OR], 1.59 [95% confidence interval [CI], 1.18-2.15]) and more penicillin-nonsusceptible strains (OR, 1.65 [95% CI, 1.06-2.59]) in women than in men; it was also found that bacteremic women were more likely to be infected with HIV (OR, 1.85 [95% CI, 1.26-2.71]) and to be younger (OR, 1.72 [95% CI, 1.25-2.36]) than were men. Thus, conjugate pneumococcal vaccination of children may reduce, in particular, both antibiotic resistance and the burden of conjugate vaccine serotype pneumococcal disease in young, HIV-infected women.