SummaryBackgroundPyrazinamide and fluoroquinolones are essential antituberculosis drugs in new rifampicin-sparing regimens. However, little information about the extent of resistance to these drugs at the population level is available.MethodsIn a molecular epidemiology analysis, we used population-based surveys from Azerbaijan, Bangladesh, Belarus, Pakistan, and South Africa to investigate resistance to pyrazinamide and fluoroquinolones among patients with tuberculosis. Resistance to pyrazinamide was assessed by gene sequencing with the detection of resistance-conferring mutations in the pncA gene, and susceptibility testing to fluoroquinolones was conducted using the MGIT system.FindingsPyrazinamide resistance was assessed in 4972 patients. Levels of resistance varied substantially in the surveyed settings (3·0–42·1%). In all settings, pyrazinamide resistance was significantly associated with rifampicin resistance. Among 5015 patients who underwent susceptibility testing to fluoroquinolones, proportions of resistance ranged from 1·0–16·6% for ofloxacin, to 0·5–12·4% for levofloxacin, and 0·9–14·6% for moxifloxacin when tested at 0·5 μg/mL. High levels of ofloxacin resistance were detected in Pakistan. Resistance to moxifloxacin and gatifloxacin when tested at 2 μg/mL was low in all countries.InterpretationAlthough pyrazinamide resistance was significantly associated with rifampicin resistance, this drug may still be effective in 19–63% of patients with rifampicin-resistant tuberculosis. Even though the high level of resistance to ofloxacin found in Pakistan is worrisome because it might be the expression of extensive and unregulated use of fluoroquinolones in some parts of Asia, the negligible levels of resistance to fourth-generation fluoroquinolones documented in all survey sites is an encouraging finding. Rational use of this class of antibiotics should therefore be ensured to preserve its effectiveness.FundingBill & Melinda Gates Foundation, United States Agency for International Development, Global Alliance for Tuberculosis Drug Development.
In this study, direct-plate culture method alone, or in combination with enrichment culture for isolation of Vibrio cholerae O139 from faecal samples at a Diarrhoea Treatment Centre in Dhaka, Bangladesh had been evaluated. Faecal samples of 528 patients with acute phase of diarrhoea, attended the Centre, were cultured directly onto thiosulfate-citrate-bile-salts-sucrose agar (direct-TCBSA) and tellurite-taurocholate-gelatin agar (direct-TTGA) and after 6-h and overnight enrichment in alkaline-bile-peptone-broth for V. cholerae O139 (ABPB) [6h-ABPB-TCBSA and 6h-ABPB-TTGA, and overnight-ABPB-TCBSA and overnight-ABPBTTGA]. Direct-TTGA-plating and overnight-ABPB-TTGA methods (latter for samples yielding negative results by overnight-direct-TTGA cultures) were also performed for another 18,647 faecal samples submitted for culture in our laboratory and 1,552 rectal swabs transported in Cary-Blair medium during investigation of acute diarrhoea outbreaks in the country. During acute phase of diarrhoea, direct-TCBSA, or direct-TTGA cultures equally supported O139 growth, while direct-plating plus 6-h, or overnight enrichment cultures were not superior as compared to the direct-plating. Direct-TTGA-plating plus overnight-ABPB-TTGA increased O139 isolation from transported rectal swabs. Thus, direct-plating provides optimum stool culture results for V. cholerae O139 during acute phase of diarrhoea. However, a combination of direct-TTGA-plating and overnight- ABPB-TTGA cultures was useful for isolation of V. cholerae O139 from transported rectal swab samples. Keywords: Cholera, Vibrio cholerae O139, enrichment cultures, direct-plate cultureDOI: http://dx.doi.org/10.3329/bjm.v23i2.880 Bangladesh J Microbiol, Volume 23, Number 2, December 2006, pp 140-144
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