Suitable Disk Antimicrobial Susceptibility Breakpoints Defining Salmonella enterica Serovar Typhi Isolates with Reduced Susceptibility to Fluoroquinolones
| Autor: | Sabina Dongol, Jeremy Farrar, Chau Tran Thuy, Leon Ochiai, Pham Thanh Duy, Tran Vu Thieu Nga, Ha Vinh, Nguyen Van Minh Hoang, Sujit K. Bhattacharya, Baiqing Dong, Christopher M. Parry, John Wain, Do Gia Canh, Christiane Dolecek, Stephen Baker, Nguyen Tran Chinh, James Campbell, Tran Tinh Hien, Buddha Basnyat, Amit Arjyal, John D. Clemens, Abhilasha Karkey, Zulfiqar A Bhutta, Magdarina D. Agtini, Aliya Naheed |
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| Rok vydání: | 2010 |
| Předmět: |
DNA Topoisomerase IV
Ofloxacin Nalidixic acid medicine.drug_class Microbial Sensitivity Tests Drug resistance Biology Salmonella typhi Microbiology Nalidixic Acid Bacterial Proteins Ciprofloxacin Drug Resistance Bacterial medicine Humans Pharmacology (medical) Agar diffusion test Antibacterial agent Pharmacology bacterial infections and mycoses Quinolone Anti-Bacterial Agents Infectious Diseases DNA Gyrase Susceptibility Mutation Fluoroquinolones medicine.drug |
| Zdroj: | Antimicrobial Agents and Chemotherapy |
| ISSN: | 1098-6596 0066-4804 |
| DOI: | 10.1128/aac.00963-10 |
| Popis: | Infections with Salmonella enterica serovar Typhi isolates that have reduced susceptibility to ofloxacin (MIC ≥ 0.25 μg/ml) or ciprofloxacin (MIC ≥ 0.125 μg/ml) have been associated with a delayed response or clinical failure following treatment with these antimicrobials. These isolates are not detected as resistant using current disk susceptibility breakpoints. We examined 816 isolates of S. Typhi from seven Asian countries. Screening for nalidixic acid resistance (MIC ≥ 16 μg/ml) identified isolates with an ofloxacin MIC of ≥0.25 μg/ml with a sensitivity of 97.3% (253/260) and specificity of 99.3% (552/556). For isolates with a ciprofloxacin MIC of ≥0.125 μg/ml, the sensitivity was 92.9% (248/267) and specificity was 98.4% (540/549). A zone of inhibition of ≤28 mm around a 5-μg ofloxacin disc detected strains with an ofloxacin MIC of ≥0.25 μg/ml with a sensitivity of 94.6% (246/260) and specificity of 94.2% (524/556). A zone of inhibition of ≤30 mm detected isolates with a ciprofloxacin MIC of ≥0.125 μg/ml with a sensitivity of 94.0% (251/267) and specificity of 94.2% (517/549). An ofloxacin MIC of ≥0.25 μg/ml and a ciprofloxacin MIC of ≥0.125 μg/ml detected 74.5% (341/460) of isolates with an identified quinolone resistance-inducing mutation and 81.5% (331/406) of the most common mutant (carrying a serine-to-phenylalanine mutation at codon 83 in the gyrA gene). Screening for nalidixic acid resistance or ciprofloxacin and ofloxacin disk inhibition zone are suitable for detecting S. Typhi isolates with reduced fluoroquinolone susceptibility. |
| Databáze: | OpenAIRE |
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