Evaluation of the GenoType MTBDRsl Version 2.0 Assay for Second-Line Drug Resistance Detection of Mycobacterium tuberculosis Isolates in South Africa.

Early detection of resistance to second-line antituberculosis drugs is important for the management of multidrug-resistant tuberculosis (MDR-TB). The GenoType MTBDRsl version 2.0 (VER 2.0) line probe assay has been redesigned for molecular detection of resistance-conferring mutations of fluoroquinolones (FLQ) (gyrA and gyrB genes) and second-line injectable drugs (SLID) (rrs and eis genes). The study evaluated the diagnostic performance of the GenoType MTBDRsl VER 2.0 assay for the detection of second-line drug resistance compared with phenotypic drug susceptibility testing (DST), using the Bactec MGIT 960 system on Mycobacterium tuberculosis complex isolates from South Africa. A total of 268 repository isolates collected between 2012 and 2014, which were rifampin monoresistant or MDR based on DST, were selected. MTBDRsl VER 2.0 testing was performed on these isolates and the results analyzed. The MTBDRsl VER 2.0 sensitivity and specificity indices for culture isolates were the following: FLQ, 100% (95% confidence interval [CI] 95.8 to 100%) and 98.9% (95% CI, 96.1 to 99.9%); SLID, 89.2% (95% CI, 79.1 to 95.6%) and 98.5% (95% CI, 95.7 to 99.7%). The sensitivity and specificity observed for individual SLID were the following: amikacin, 93.8% (95% CI, 79.2 to 99.2%) and 98.5% (95% CI, 95.5 to 99.7%); kanamycin, 89.2% (95% CI, 79.1 to 95.6%) and 98.5% (95% CI, 95.5 to 99.7%); and capreomycin, 86.2% (95% CI, 68.3 to 96.1%) and 95.9% (95% CI, 92.2 to 98.2%). An interoperator reproducibility of 100% and an overall interlaboratory performance of 93% to 96% were found. The overall improvement in sensitivity and specificity with excellent reproducibility makes the GenoType MTBDRsl VER 2.0 a highly suitable tool for rapid screening of clinical isolates for second-line drug resistance for use in high-burden TB/HIV settings.

Pseudomonas aeruginosa bacteraemia in an academic hospital in South Africa.

OBJECTIVES: The aim of the study was to determine the clinical manifestations, outcome of and prognostic factors associated with Pseudomonas aeruginosa bacteraemia at Chris Hani Baragwanath Hospital, Johannesburg, during the period 1998 - 1999, to describe and quantify resistance to antipseudomonal drugs, to characterise bacteraemic isolates, and to investigate the clustering and genotype distribution of drug-susceptible and multiply-resistant strains in the hospital. METHODS: Clinical and laboratory investigations, culture and antimicrobial susceptibility testing were performed. Bacteraemic isolates were typed by endonuclease macrorestriction. Those with > or = 97% band pattern similarity were assigned genotype status. RESULTS: Of 91 P. aeruginosa blood isolates, 52 (57.1%) were nosocomially acquired. Underlying conditions associated with episodes were burns in 24 (28%) and HIV infection in 21 (24%). Multidrug resistance was present in 14 (15.4%) of isolates from 91 episodes. In 79 episodes where the outcome was known, 37 (46.8%) of the patients died. Case fatality rates were 75% in adults and 25% in children. Being a child, receiving appropriate antimicrobial treatment and admission to a specialised care unit were significantly associated with improved prognosis. CONCLUSION: P. aeruginosa bacteraemia was associated with outbreaks caused by two multiply-resistant genotypes. Eighteen antimicrobial-susceptible isolates from bacteraemic episodes in paediatric wards, 9 in HIV-seropositive children, could be linked to small outbreaks in both hospitalised and community-based children.

Tuberculosis culture testing at a tertiary care hospital: options for improved management and use for treatment decisions.

SETTING: Chris Hani Baragwanath Hospital, a tertiary care hospital in Johannesburg, South Africa. OBJECTIVES: To determine the proportion of patients with positive Mycobacterium tuberculosis cultures and whether those who were positive were on treatment. DESIGN: Tuberculosis (TB) culture results were obtained from the laboratory for a 3-month period. Positive results were checked against registrations at the hospital TB Care Centre (TBCC). The treatment status of non-registered patients was obtained from various records at the hospital, district clinics and from home visits. RESULTS: Overall, 3909 patients had 5404 samples sent for culture. Of these, 708 patients (18%) had at least one positive culture. The positive yield from 2749 adult sputum samples was 33% and ranged from 6% to 40% for different extra-pulmonary specimens. Among 1160 children, the yield varied from 0% to 12%, with 12% in sputum and gastric washing specimens. Of the 708 culture-positive patients, 429 (61%) patients were registered at the TBCC and were known to have started TB treatment. Of the 279 subjects not registered (39% overall), 100 (36%) died. Only 67 of the 179 survivors were confirmed on treatment, 40 were not on treatment and 72 could not be traced. CONCLUSIONS: Large numbers of TB culture tests were performed, some inappropriately. Study findings highlight inadequacies in the management of culture-confirmed TB at this hospital.

The influence of concomitant HIV infection on the serological diagnosis of primary syphilis in southern Africa.

The authors investigated the utility of both a nontreponemal (RPR) test and a treponemal (FTA-ABS) test for the diagnosis of primary syphilis during the emergence of the HIV epidemic in southern Africa. The serological tests were performed on 868 patients with genital ulcerations, seen in five centres. While primary syphilis was diagnosed by multiplex PCR in 163 cases (18.8%), the overall RPR and FTA-ABS seroprevalences were 24.3% and 51.5% respectively. The sensitivities of the RPR and FTA-ABS to detect primary syphilis were 69.3% and 89.6% respectively, while the specificities were 86.1% and 58.5% respectively. The performance characteristics of these tests were influenced negatively by concomitant HIV infection and the presence of other genital ulcer disease pathogens in lesions found to be Treponema pallidum PCR positive.

Emergence of a pneumococcal clone with cephalosporin resistance and penicillin susceptibility.

We report two South African serotype 6B pneumococcal isolates with cephalosporin resistance, yet with susceptibility to penicillin. DNA fingerprinting revealed that they were clonal in origin. pbp 2X and 1A genes showed major alterations typical of cephalosporin-resistant pneumococci. The pbp 2B gene was completely unaltered, explaining the penicillin susceptibility of the isolates.

Meningococcal disease in South African goldmines--epidemiology and strategies for control.

OBJECTIVES: To describe the epidemiology of meningococcal disease in South African goldmines and to suggest strategies for the prevention and control of further outbreaks. DESIGN: We prospectively investigated a meningococcal outbreak that occurred in 1996 and describe the control measures that were implemented. In addition, we conducted a retrospective analysis of routinely collected data on meningococcal disease in these mines from 1972 to 1996. SETTING: Four goldmines in Gauteng, employing 30,000 workers who live in hostels. SUBJECTS: All cases of meningococcal disease at the mine hospital. RESULTS: Between 1972 and 1976, 588 cases were diagnosed, with peaks in 1972 (203 cases, 727/100,000) and 1975 (147 cases, 564/100,000). Since 1978 less than 5 cases have been reported in most years, but smaller outbreaks occurred in 1990 (30 cases, 89/100,000) and 1996 (14 cases, 50/100,000). The 1996 outbreak (group A, clone I-1) was part of a larger outbreak in Gauteng that originated in Mozambique and began in one mine in July 1996, after which a mass vaccination campaign was implemented. This was followed by a smaller outbreak among non-vaccinated workers at an adjacent mine. Five patients were new recruits. CONCLUSIONS: Despite a dramatic reduction in meningococcal disease over the last 25 years due mainly to changes in the work force, there are still outbreaks in this community. Those most at risk are young men who are new to the industry. Suggestions for prevention include effective surveillance, routine vaccination of new recruits and a rapid response to outbreaks, with mass vaccination and provision of chemoprophylaxis to close contacts.

Meningitis in a community with a high prevalence of tuberculosis and HIV infection.

OBJECTIVES: To evaluate the spectrum of aetiologies, and distinguishing clinical and laboratory features, of meningeal infection in a community with a high prevalence of tuberculosis (TB) and HIV infection. SETTING: A hospital serving mineworkers, originating from rural areas of Southern Africa. DESIGN: Prospective cohort of 60 consecutive lumbar punctures (LPs), performed for suspected meningitis. MEASUREMENTS: Clinical history and examination; concurrent cerebrospinal fluid (CSF) and blood samples; mortality status six months after entry to study. RESULTS: 38 of 57 patients (66.7%) were HIV-1 positive, 59.5% of whom had a CD4 count <200 cells/mm3. Nine patients had tuberculous meningitis (TBM) and two had tuberculomas; four developed disease while on TB therapy. There was one case of multidrug, and two of isoniazid-resistant TBM. There were nine episodes of cryptococcal meningitis (seven patients), nine of aseptic meningitis, two of neurosyphilis and 20 normal LPs, including four with AIDS dementia complex (ADC). Ten patients with meningococcal infection, part of a larger outbreak, were significantly younger (p=0.004). All patients with tuberculous, cryptococcal (most immune-suppressed p<0.001) and aseptic meningitis were HIV-1 positive. Within six months, 19 patients had died. Death was associated with HIV positivity (p=0.004), low CD4 count (p<0.001) and a diagnosis of cryptococcal meningitis, CNS TB or ADC. CONCLUSION: HIV has a major impact on the burden of disease and mortality, with a predominance of opportunistic chronic meningitides, despite a meningococcal outbreak, in this community. Of concern is the development of TBM despite therapy, and the emergence of drug-resistant strains.

Epidemic spread of subgroup III of Neisseria meningitidis serogroup A to South Africa in 1996.

A total of 111 strains of Neisseria meningitidis isolated during a meningitis outbreak in Johannesburg, South Africa, in 1996 were analyzed by serogrouping, arbitrarily primed polymerase chain reaction analysis, ribotyping, and multilocus enzyme electrophoresis. Nineteen different clusters were identified, and typing patterns for the three techniques were comparable. Of the 111 strains analyzed, 55 (49.5%) belonged to the serogroup A clone complex designated internationally as subgroup I-1. The second largest cluster included 15 isolates (13.5%) that were identified as belonging to the pandemic clone III-1. A number of unrelated strains were also encountered. Our study provides the first documented evidence of the presence of clone III-1 in South Africa and indicates the continued spread of this clone well outside the African meningitis belt.

Dual infective pathology in patients with cryptococcal meningitis.

Coinfection of the nervous system by two distinct nonviral organisms is uncommon and often undiagnosed. Medical teaching emphasizes that a single pathologic process should be sought; however, in the presence of severe immunocompromise this approach may not hold true. We describe seven HIV-1 seropositive patients with cryptococcal meningitis, three of whom had a proven nervous system infection with a second organism: concurrent tuberculous meningitis, a tuberculoma, and the first documented case of cryptococcal meningitis and neurosyphilis.

Molecular epidemiology of an outbreak of Enterobacter cloacae in the neonatal intensive care unit of a provincial hospital in Gauteng, South Africa.

An outbreak of Enterobacter cloacae in the neonatal intensive care unit of a provincial hospital in Gauteng, South Africa, resulting in nine deaths was investigated. Macrorestriction analysis using pulsed-field gel electrophoresis revealed that three isolates of E. cloacae from blood cultures of patients, six from environmental sources, and one from the hands of a staff member belonged to the same genotypic cluster.

Increased activity of 16-membered lactone ring macrolides against erythromycin-resistant Streptococcus pyogenes and Streptococcus pneumoniae: characterization of South African isolates.

The susceptibility of 40 erythromycin-resistant isolates of Streptococcus pyogenes and 40 multiply-resistant isolates of Streptococcus pneumoniae to six macrolide antibiotics, representing 14-, 15- and 16-membered lactone ring structures, was tested. The genetic basis for macrolide resistance in the strains was also determined. Both erm and mef determinants were encountered in the 36 S. pneumoniae isolates tested, but only mef in the five S. pyogenes isolates tested. All isolates showed cross-resistance among the 14-membered macrolides erythromycin, clarithromycin and roxithromycin and the 15-membered macrolide, azithromycin. However, the erythromycin-resistant S. pyogenes isolates retained full susceptibility to spiramycin and josamycin (16-membered agents). These latter two antibiotics were also more active than the other macrolides against erythromycin-resistant S. pneumoniae isolates, especially josamycin which was 8-64 times more active than erythromycin; spiramycin was only two to eight times more active than erythromycin.

Rothia dentocariosa endocarditis and aortic root abscess.

We report a case of endocarditis and associated paravalvular abscess due to Rothia dentocariosa which did not respond to antibiotic therapy. Nine case reports describing endocarditis caused by this organism, formerly thought to be non-pathogenic, have been recorded in the literature. The isolates were extremely sensitive to penicillin, and eight patients responded to this agent which, in most cases, was used in combination with an aminoglycoside. Surgery is recommended for an associated abscess, as the outcome in the two recorded cases has been fatal.

Antibiotic resistance of nasopharyngeal isolates of Streptococcus pneumoniae from children in Lesotho.

Villages associated with the Lesotho Highlands Development Agency were randomized with a bias in favour of larger villages, and children < 5 years of age from cluster-randomized households in these villages were chosen for the assessment of antibiotic resistance in pneumococci. Children of the same age group attending clinics in the capital, Maseru, were selected for comparison. Nasopharyngeal cultures of Streptococcus pneumoniae from both groups of children were examined for antibiotic resistance and a questionnaire was used to assess risk factors for the acquisition of resistant strains. Carriage of penicillin- and tetracycline-resistant pneumococci was significantly higher among 196 Maseru children compared with 324 rural children (P < 0.05 and P = 0.01, respectively). Maseru children tended to visit clinics at an earlier age compared with their rural counterparts. The rural children were less exposed to antibiotics (P < 0.01), were less frequently hospitalized (P < 0.001), and rarely attended day care centres (P < 0.001). The very low incidence of antibiotic resistance in rural Lesotho and the higher incidence in Maseru are in stark contrast with the much higher frequencies found in the Republic of South Africa, many European countries, and the USA.