SETTING: King George V (KGV) Hospital has the largest tuberculosis (TB) facility in KwaZulu-Natal (KZN), the province with the highest prevalence of TB-HIV (human immunodeficiency virus) co-infection in South Africa. During the study, KGV was the only provincial referral hospital for patients with drug-resistant TB. OBJECTIVE: To determine the role of nosocomial transmission in patients infected with a new strain of Mycobacterium tuberculosis during treatment. DESIGN: Insertion sequence 6110-DNA fingerprinting was performed on stored isolates from patients with culture-positive pulmonary TB for more than 6 weeks after treatment started and those who relapsed. RESULTS AND CONCLUSION: DNA fingerprints of 14 of 26 patients with differing isolates matched those of other patients. Four of them acquired a F15/LAM4/KZN genotype, while two acquired fully susceptible Beijing strains. Three of the four F15/LAM4/KZN strains were multidrug-resistant with identical fingerprint patterns, while the fourth was fully susceptible. One of these was acquired during hospitalisation and three after discharge. Both HIV-infected and non-infected patients are at risk of infection with the F15/LAM4/KZN strain in health care facilities and within the community. Rapid diagnostic tests, separation of TB and non-TB patients on admission and isolation of multidrug-resistant and extensively drug-resistant TB patients are essential to curb nosocomial transmission.

The KZN strain family of Mycobacterium tuberculosis is a highly virulent strain endemic to the KwaZulu-Natal region of South Africa, which has recently experienced an outbreak of extensively-drug resistant tuberculosis. To investigate the causes and evolution of drug-resistance, we determined the DNA sequences of several clinical isolates - one drug-susceptible, one multi-drug resistant, and nine extensively drug-resistant - using whole-genome sequencing. Analysis of polymorphisms among the strains is consistent with the drug-susceptibility profiles, in that well-known mutations are observed that are correlated with resistance to isoniazid, rifampicin, kanamycin, ofloxacin, ethambutol, and pyrazinamide. However, the mutations responsible for rifampicin resistance in rpoB and pyrazinamide in pncA are in different nucleotide positions in the multi-drug-resistant and extensively drug-resistant strains, clearly showing that they acquired these mutations independently, and that the XDR strain could not have evolved directly from the MDR strain (though it could have arisen from another similar MDR strain). Sequencing of eight additional XDR strains from other areas of KwaZulu-Natal shows that they have identical drug resistant mutations to the first one sequenced, including the same polymorphisms at sites associated with drug resistance, supporting the theory that this represents a case of clonal expansion.

Extensively drug-resistant tuberculosis (XDR TB) has been detected in most provinces of South Africa, particularly in the KwaZulu-Natal province where several hundred cases have been reported since 2004. We analyzed the transmission dynamics of XDR TB in the region using mathematical models, and observed that nosocomial transmission clusters of XDR TB may emerge into community-based epidemics under the public health conditions of many South African communities. The effective reproductive number of XDR TB in KwaZulu-Natal may be around 2. Intensified community-based case finding and therapy appears critical to curtailing transmission. In the setting of delayed disease presentation and high system demand, improved diagnostic approaches may need to be employed in community-based programs rather than exclusively at tertiary hospitals. Using branching process mathematics, we observed that early, community-based drug-susceptibility testing and effective XDR therapy could help curtail ongoing transmission and reduce the probability of XDR TB epidemics in neighboring territories.

Background.@nbsp; Multidrug-resistant (MDR) and extensively drug-resistant (XDR) tuberculosis (TB) are now major threats in areas of South Africa with a high prevalence of TB and human immunodeficiency virus (HIV) infection. The role of exogenous reinfection as a cause of MDR and XDR TB in these settings has not been determined. Methods.@nbsp; We reviewed data from patients with culture-positive TB who later developed MDR or XDR TB in Tugela Ferry, KwaZulu-Natal, South Africa during 2005-2006. We performed spoligotyping on initial isolates (obtained at the time of treatment initiation) and follow-up isolates obtained from these patients. Results.@nbsp; We identified 23 patients who developed MDR or XDR TB after being treated for less resistant TB between June 2005 and June 2006. Both initial and follow-up isolates were available for spoligotyping for 17 of these patients. In all cases, the follow-up isolates' spoligotypes differed from those of the initial isolate, indicating exogenous reinfection. Two genotypes (shared type [ST] 34 and ST 60, associated with MDR and XDR TB, respectively) were responsible for 85% of reinfections. All 17 patients had been hospitalized; all 15 whose HIV infection status was known were HIV-infected. Conclusions.@nbsp; Exogenous reinfection is an important mechanism for the development of MDR and XDR TB. In addition to strengthening TB treatment programs, effective infection control strategies are urgently needed to reduce the transmission of MDR and XDR TB.

OBJECTIVES: Syndromic sexually-transmitted infection (STI) treatment remains a cost-saving HIV prevention intervention in many countries in Africa. We estimate the effectiveness of syndromic treatment for curable STIs in rural KwaZuluNatal, South Africa and the trend in STI prevalences before and after the introduction of syndromic treatment in 1995. METHODS: Data were available from various clinical studies, surveys of public and private health providers, the general-population and women attending ante-natal, family planning and child-immunisation clinics in rural northern KwaZuluNatal between 1987 and 2004. Overall effectiveness was defined as the estimated proportion of the annual number of symptomatic curable STI episodes cured by syndromic treatment, based on separate estimates for six curable STI aetiologies by gender. RESULTS: Median overall effectiveness was 13.1%(95%CI 8.9-17.8%) of symptomatic curable STI episodes cured. Effectiveness increased to 25.0%(17.3-33.8%), 47.6%(44.5-50.8%), or 14.3%(9.9-19.4%) if 100% treatment-seeking, 100% correct treatment-provision or 100% cure were assumed, respectively. Time-trends were difficult to assess formally but there was little evidence of decreasing STI prevalences. Including incurable, but treatable HSV-2 ulcers in the effectiveness calculation would halve the proportion of ulcers cured or correctly treated, but this reduction could be entirely countered by including episodic antiviral-treatment in the national guidelines. CONCLUSION: Overall effectiveness of syndromic treatment for curable STIs in rural KwaZuluNatal remains low, and there is little evidence of reduced curable STI prevalences. As syndromic treatment is likely to be a cost-saving HIV prevention intervention in South Africa, innovative strategies are urgently needed to increase rates of treatment-seeking and correct-treatment provision.

SETTING: Current treatment for pulmonary tuberculosis (TB) might be shortened by the incorporation of fluoroquinolones (FQs). OBJECTIVES: A Phase II study aimed to assess the sterilising activities of three novel regimens containing FQs before a Phase III trial of a 4-month regimen containing gatifloxacin (GFX). DESIGN: A total of 217 newly diagnosed smear-positive patients were randomly allocated to one of four regimens: isoniazid (INH), pyrazinamide and rifampicin (RMP) with either ethambutol, GFX, moxifloxacin (MFX) or ofloxacin (OFX) for 2 months. At the end of the study, RMP and INH were given for 4 months. The rates of elimination of Mycobacterium tuberculosis were compared in the regimens using non-linear mixed effects modelling of the serial sputum colony counts (SSCC) during the first 8 weeks. RESULTS: After adjustment for covariates, MFX substitution appeared superior during the early phase of a bi-exponential fall in colony counts, but significant and similar acceleration of bacillary elimination during the late phase occurred with both GFX and MFX (P = 0.002). Substitution of OFX had no effect. These findings were supported by estimates of time to conversion, using Cox regression, but there were no significant differences in proportions culture-negative at 8 weeks. CONCLUSIONS: GFX and MFX improve the sterilising activity of regimens and might shorten treatment; their progression into Phase III trials therefore seems warranted.

In this study, we report the presence of a novel plasmid-mediated AmpC-type beta-lactamase that was isolated from 3 clinical Escherichia coli isolates at a tertiary teaching hospital in Durban, South Africa. The nucleotide sequence of the genes encoding this novel beta-lactamase was found to be >94% identical to the nucleotide sequences of the plasmid-mediated AmpC-type beta-lactamases originating from Citrobacter freundii. This enzyme differed from CMY-2 by 3 amino acid substitutions and was designated CMY-20.

To examine the safety of formula feeds used by mothers participating in a Prevention of Mother-to-Child Transmission (PMTCT) programme, contents of 94 feeding bottles collected at a PMTCT-clinic were analysed. An additional 17 samples were taken from already prepared feeds during home visits, as well as 21 samples from bottles prepared under observation. Living conditions and educational levels were overall good and mothers had been counselled on safe formula preparation. Samples were analysed for faecal bacteria, using Escherichia coli and Enterococcus sp. as indicators. Protein concentration was used as an indicator of concentration of the formula. Out of 94, 63 (67%) of samples obtained at the clinic and 13/16 (81%) of available home samples were contaminated with faecal bacteria, compared to 8/21 (38%) of those prepared under observation. Out of 94, 58 (62%) of the clinic samples containing E. coli and 23/94 (24%) of those containing Enterococcus sp. were contaminated with more than the US government recommended limit of 10 CFU/ml. Out of 94, 26 (28%) of samples obtained at the clinic, 8/17 (47%) of home samples and 3/21 (14%) of those prepared under observation were over-diluted, compared to standards. Many mothers did not follow recommended practices in preparing and feeding the bottles.

Vibrio cholerae O1 serotype Ogawa and serotype Inaba isolates from the cholera epidemic that occurred in 2001 and 2002 in South Africa were compared with isolates of V. cholerae O1 serotype Inaba from the epidemic that occurred between 1980 and 1987. PFGE using NotI digestion was used to compare stored isolates received during the 1980s epidemic with those received during the epidemic in 2001/2002. A selected number of these isolates were then sequenced to compare the sequence of the wbeT gene in the V. cholerae O1 Ogawa strains of 2001/2002 with that in the V. cholerae O1 Inaba strains of the 1980s and 2001/2002. Isolates from the recent epidemic were shown to be related, irrespective of serotype, and had comparable banding patterns on PFGE, using NotI. They were distinctly different from those from the previous epidemic. Sequencing of the wbeT gene showed that the gene was highly conserved between the two epidemics. A single deletional mutation of an adenine residue was observed in the V. cholerae serotype Inaba isolates from the 2001/2002 epidemic, resulting in the serotype switch between the V. cholerae O1 strains from the recent epidemic. The distinct differences in PFGE patterns among isolates from the first and second epidemics exclude the possibility that the Inaba strain from the 1980s became dormant in the environment and mutated to serotype Ogawa, causing the 2001/2002 epidemic, despite the apparent consistency in the site of mutation in the Inaba serotypes between the two epidemics.