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.

Dried culture spots for Xpert MTB/RIF external quality assessment: results of a phase 1 pilot study in South Africa.

Implementation of Xpert MTB/RIF requires quality assessment. A pilot program using dried culture spots (DCSs) of inactivated Mycobacterium tuberculosis is described. Of 274 DCS results received, 2.19% generated errors; the remainder yielded 100% correct Mycobacterium tuberculosis detection. The probe A cycle threshold (C(T)) variability of three DCS batches was ≤ 3.47. The study of longer-term DCS stability is ongoing.

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.

Penicillin pharmacokinetics in kwashiorkor.

Intravenous penicillin kinetics have been studied in eight children with kwashiorkor on admission to hospital and when rehabilitated. A 75% increase in penicillin clearance was observed with recovery, associated with a fall in half-life; this was probably due to an improvement of both renal plasma flow and tubular function. The present observations and those of other authors working in this area are discussed and an approach to drug dosage of renally excreted drugs in kwashiorkor has been proposed.

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.

Cefadroxil compared with cefaclor in the treatment of streptococcal pneumonia in adults.

103 young male Black African gold-miners with pneumococcal pneumonia confirmed by culture or serology were randomly assigned to receive the long acting oral cephalosporin cefadroxil 1 g every 12 hours or cefaclor 500 mg every 8 hours for 10 days. Clinical cures were obtained in 94% of the group who received cefadroxil and in 94% of the cefaclor group. Similarly, the causative organism S. pneumoniae was eradicated in 98% and 96% of patients who received cefadroxil and cefaclor, respectively. Minimal side effects occurred in both groups, although 1 patient withdrew from therapy with cefaclor because of severe diarrhoea. Thus, cefadroxil and cefaclor both displayed effective antimicrobial activity with low toxicity in the treatment of pneumococcal pneumonia.

A reevaluation of sputum microscopy and culture in the diagnosis of pulmonary tuberculosis.

This prospective study was undertaken to determine the interpretation of "scanty-positive" acid-fast bacilli on microscopy and to reevaluate simultaneous microscopy and culture of sputum for the accurate diagnosis of pulmonary tuberculosis (PTB). A total of 2,560 specimens were processed from 727 patients. There were 435 positive specimens (17.0 percent), originating from 139 patients, 10 by microscopy only, 176 by culture only, and 249 on both microscopy and culture. Review of the hospital records showed that 107 patients had PTB, 1 had Mycobacterium kansasii colonization, and 31 were thought not to have PTB. Sensitivity and specificity were 53.1 and 99.8 percent for microscopy, 81.5 and 98.4 percent for culture, and 77.6 and 100 percent for microscopy and culture, respectively. Seventy-five microscopy specimens (46 patients) were reported as scanty-positive, of which five (four patients) were deemed false positives, yielding a positive predictive value of 93.3 percent. In those patients with positive sputum microscopy, acid-fast bacilli were detected in one of the first four specimens. Seven isolates (three patients) were mycobacteria other than tubercle (0.27 percent of specimens and 1.6 percent of mycobacteria cultured). Despite the ready availability of laboratory evidence of disease, only 73 percent of cases were diagnosed by ward staff and 36 percent notified by the primary physician. Eleven patients (10.3 percent) died, six of whom had not received diagnoses of PTB before death. Sputum microscopy and culture remains reliable despite Bayesian predictions when applied to a population with a decreasing incidence of tuberculosis.

The risk of infection from Giardia lamblia due to drinking water supply, use of water, and latrines among preschool children in rural Lesotho.

Stool samples were collected from 267 rural, preschool children in four districts in Lesotho during October-November, 1984. Sixty-three children (23.6%) were tested positive for Giardia lamblia, the most commonly recovered parasite from stool samples. The use of low amounts of water for personal hygiene was associated significantly with having G. lamblia (OR = 2.42), but the use of traditional, non-improved drinking water sources (OR = 1.38) or lack of latrines (OR = 0.94) was not. Although G. lamblia may be primarily waterborne in developed countries, the amount of water that is used for personal and domestic hygiene may be more important than the quality of drinking water in developing countries. Other risk factors that were identified to be associated significantly with having or not having Giardia were child older than 24 months (OR = 6.79), mother less than 20 years of age (OR = 5.18), residing in Mohales Hoek district (OR = 2.33), and possessing several agricultural tools (OR = 0.70).

Community-acquired pneumonia of diverse aetiology: prognostic features in patients admitted to an intensive care unit and a "severity of illness" core.

In a retrospective study of 73 patients with community-acquired lobar pneumonia of diverse aetiology admitted to an intensive care unit, an attempt was made to identify those factors among the demographic and clinical features and results of initial laboratory investigations that were predictive of the ultimate outcome. A lower mean white cell count (p = 0.03), platelet count (p = 0.02), total serum protein (p = 0.005) and albumin (p = 0.02) and a higher mean serum creatinine (p = 0.03) and phosphate level (p = 0.02) appeared to be predictive of a poor prognosis. The most significant variable predictive of mortality, was the presence of bacteraemia (p = 0.0005). Severity of illness scoring systems by omitting microbiological data appear to underestimate predicted patient mortality. The mortality rate of critically ill patients with community-acquired lobar pneumonia remains high, despite advances in antimicrobial chemotherapy and intensive care unit facilities, particularly in the presence of certain negative prognostic factors of which the presence of bacteraemia is the most important.

Nucleotide sequence of dihydrofolate reductase type VI.

The complete sequence of the type VI dihydrofolate reductase (DHFR) gene from plasmid pUK672 was determined. The structural gene coded for a polypeptide of 157 amino acids which had a deduced mol. wt of 17,424. Comparison with amino-acid sequences of the type I, type V and Escherichia coli K12 chromosomal DHFRs showed that there was 63%, 61% and 31% homology respectively. Putative RNA polymerase and ribosomal binding sites were identified proximal to the initiation codon and a feature consistent with transcription termination was present distal to the coding region. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis showed that the enzyme had a subunit mol. wt of 17,500.

Comparison of preservation media and freezing conditions for storage of specimens of faeces.

To evaluate the long-term recoverability of bacterial enteropathogens, two freezing conditions (deep-freezing at -70 degrees C and liquid nitrogen) and three preservation media (Cary-Blair, Amies, and buffered glycerol-saline) were tested. These were compared with storage in containers with no preservation medium and refrigeration at 4 degrees C. At 4 degrees C, viability of organisms could not be consistently maintained beyond one month; Cary-Blair medium generally gave the best results and storage without preservation medium was the least efficient. Storage in liquid nitrogen and deep-freezing effectively preserved all organisms except Campylobacter jejuni for the entire period of study (12 months). There was no difference between the various preservation media, or between storage with or without medium. Storage in preservation medium was superior to storage without such supplement for C. jejuni. We conclude that most enteropathogens survive in faecal specimens for as long as 12 months when stored at very low temperatures (-70 degrees C) whether or not preservation media are used.

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.

Corneal ulceration at an urban African hospital.

During a one-year survey 283 corneal ulcers from 274 patients were seen at St John's Eye Unit of Baragwanath Hospital. Central bacterial ulcers constituted the largest problem, and the commonest isolate in this group was Streptococcus pneumoniae. Mycotic and dendritic keratitis were relatively uncommon, while marginal catarrhal ulceration secondary to chronic staphylococcal lid disease was frequently seen. The microbiology of the various ulcers is described, and the placing of organisms into classes is stressed in determining significance of isolates. Many of the patients were male Africans who were either manual labourers or unemployed. Half the patients had used topical antibiotics before presentation.

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.

Septic arthritis due to Cryptococcus neoformans.

Cryptococcal arthritis is rare. We report two cases, one of infection of the hip joint in a 56-year-old woman, the other of arthritis of the elbows and knees in a 4-year-old boy. Both patients were treated successfully with a combination of surgical drainage and antifungal therapy. The 15 previously published cases are reviewed. Immunodeficiency is noted in most reported cases commonly associated with the use of corticosteroids. The joint most often involved is the knee. Amphotericin B and 5-fluorocytosine have been used with success for treating this conditions. Ketoconoazole may have a role in the therapy of cryptococcal arthritis although information on the use of this agent is sparse.

Klebsiella pneumoniae bacteraemia at an urban general hospital.

Of 47 patients with Klebsiella pneumoniae bacteraemia admitted to the Hillbrow Hospital, Johannesburg during a period of 18 months, 31 were males and 16 were females. Features predisposing to illness were found in 89.4% patients, chronic alcoholism, neoplastic disease and diabetes mellitus being the most common. Twenty-five infections were acquired in hospital and 22 in the community. Most patients (59.6%) had pneumonia. All isolates of K. pneumoniae were resistant to ampicillin (100%); several (42.6%) were resistant to other antibiotics also. The overall mortality rate was 55.3%. A higher mean initial blood pressure and lower concentrations of serum urea and bilirubin were found in survivors. None of the 28 patients, surviving more than 48 h who received combined therapy with an aminoglycoside and a beta-lactam antibiotic (to which the organism was susceptible) died. Among the remaining patients treated with either an appropriate beta-lactam agent alone, an appropriate aminoglycoside alone or ciprofloxacin the combined mortality rate was 83.3% (P = 0.007).

The qualitative nitroblue tetrazolium (NBT) test as a means to differentiate between infection and rejection in renal transplant patients.

In order to determine whether immunosupression depresses the response of the NBT test to bacterial infections and to note the effect of allograft rejection on this test, a prospective study was carried out on 30 renal transplant recipients. 12 of 30 renal transplant patients developed bacterial infections and in these patients NBT readings were elevated. 12 of the remianing 18 patients who developed rejection episodes showed normal NBT results. All patients were on high doses of steroids and other immunsuppressive agents. We conclude that the NBT test may be of value in diagnosing bacterial infection in the immunsuppressed allograft recipient, and may also be an useful adjunct in the differentiation between allograft infection and bacterial infection.