{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,5,14]],"date-time":"2025-05-14T00:08:55Z","timestamp":1747181335942,"version":"3.40.5"},"reference-count":29,"publisher":"Microbiology Society","issue":"8","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2021,8,6]]},"abstract":"\n Introduction.<\/jats:bold> Fluoroquinolone (FQ) resistant \n \n Salmonella<\/jats:ext-link>\n <\/jats:named-content>\n <\/jats:italic> are classified as high priority pathogens by WHO. FQ resistance among \n \n Salmonella<\/jats:ext-link>\n <\/jats:named-content>\n <\/jats:italic> Typhi has emerged rapidly and is predominantly mediated by mutations in the topoisomerase genes gyrA<\/jats:italic>, and parC<\/jats:italic>. Mutations in GyrA result in classical FQ resistance (DCS-NAR) i.e. decreased susceptibility to ciprofloxacin (MIC of 0.12 to 0.5 \u00b5g ml\u22121<\/jats:sup>) (DCS) and resistance to nalidixic acid (NAR). Previously a nalidixic acid disc test was proposed for detection of DCS. Recently isolates with non-classical FQ resistance caused by plasmid-mediated quinolone resistance (PMQR) and mutations in GyrB have emerged. These mechanisms also result in DCS but are nalidixic acid susceptible (NAS) and thus pose diagnostic challenges. CLSI and EUCAST have recommended use of 5\u2009\u00b5g pefloxacin discs for detection of DCS in \n \n Salmonella<\/jats:ext-link>\n <\/jats:named-content>\n <\/jats:italic>.<\/jats:p>\n \n Hypothesis.<\/jats:bold> The CLSI and EUCAST recommendations for use of 5\u2009\u00b5g pefloxacin for detection of DCS has not been validated on typhoidal \n \n Salmonella<\/jats:ext-link>\n <\/jats:named-content>\n <\/jats:italic> and resistance mediated by GyrB mutation in \n \n Salmonella<\/jats:ext-link>\n <\/jats:named-content>\n <\/jats:italic> species.<\/jats:p>\n \n Aim.<\/jats:bold> The aim of the present study was to validate the performance of the 5\u2009\u00b5g pefloxacin discs to detect isolates of S<\/jats:italic>. Typhi with DCS with special reference to GyrB mutations.<\/jats:p>\n \n Methodology.<\/jats:bold> A total of 180 clinical isolates of \n \n Salmonella<\/jats:ext-link>\n <\/jats:named-content>\n <\/jats:italic> Typhi (2005\u20132014) were investigated for genetic mechanisms of resistance. Zone diameters for nalidixic acid (30\u03bcg), ciprofloxacin (5\u03bcg) and pefloxacin (5\u00b5g) and minimum inhibitory concentration (MIC) for ciprofloxacin were determined using CLSI guidelines. Performance of the three discs was evaluated to detect FQ resistance in S<\/jats:italic>. Typhi.<\/jats:p>\n \n Results.<\/jats:bold> Topoisomerase mutations in GyrB +\/ ParC and GyrB were detected in 112 and 34 isolates respectively. Different mutations have a varied effect on the MIC for ciprofloxacin. The current breakpoints for susceptible (\u22640.06 \u00b5g ml\u22121<\/jats:sup>) and non-susceptible (\u22650.125 \u00b5g ml\u22121<\/jats:sup>), failed to detect all isolates with a resistance mechanism. Performance of both ciprofloxacin and pefloxacin discs were excellent compared to nalidixic acid in differentiating isolates with non-classical resistance mediated by GyrB from wild-type.<\/jats:p>\n \n Conclusion.<\/jats:bold> The pefloxacin disc can be used to detect FQ resistance among S<\/jats:italic>. Typhi. This is the first report of validation of pefloxacin for detection of FQ resistance in S<\/jats:italic>. Typhi mediated by GyrB mutation.<\/jats:p>","DOI":"10.1099\/jmm.0.001398","type":"journal-article","created":{"date-parts":[[2021,8,6]],"date-time":"2021-08-06T14:17:18Z","timestamp":1628259438000},"source":"Crossref","is-referenced-by-count":1,"title":["Validation of Pefloxacin for detection of fluoroquinolone (FQ) resistance among Salmonella Typhi with special reference to GyrB mutations"],"prefix":"10.1099","volume":"70","author":[{"given":"Shakila Banu","family":"Inayath","sequence":"first","affiliation":[{"name":"Department of Microbiology, Vardhman Mahaveer Medical College and Safdarjung Hospital, New Delhi- 110029, India"},{"name":"Department of Microbiology, Faculty of Medicine & Health Sciences, SGT Medical College, Hospital & Research Institute, Budhera, Gurugram-122505, Haryana, India"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9679-4180","authenticated-orcid":false,"given":"Shobha","family":"Broor","sequence":"additional","affiliation":[{"name":"Department of Microbiology, Faculty of Medicine & Health Sciences, SGT Medical College, Hospital & Research Institute, Budhera, Gurugram-122505, Haryana, India"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Ruchi","family":"Gupta","sequence":"additional","affiliation":[{"name":"Department of Microbiology, Vardhman Mahaveer Medical College and Safdarjung Hospital, New Delhi- 110029, India"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5774-6837","authenticated-orcid":false,"given":"Priti","family":"Agarwal","sequence":"additional","affiliation":[{"name":"Department of Microbiology, Faculty of Medicine & Health Sciences, SGT Medical College, Hospital & Research Institute, Budhera, Gurugram-122505, Haryana, India"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1161-7578","authenticated-orcid":false,"given":"Subhradeep","family":"Majumder","sequence":"additional","affiliation":[{"name":"Department of Microbiology, Vardhman Mahaveer Medical College and Safdarjung Hospital, New Delhi- 110029, India"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0838-5841","authenticated-orcid":false,"given":"Anupam Kumar","family":"Anveshi","sequence":"additional","affiliation":[{"name":"Department of Microbiology, Vardhman Mahaveer Medical College and Safdarjung Hospital, New Delhi- 110029, India"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Rajni","family":"Gaind","sequence":"additional","affiliation":[{"name":"Department of Microbiology, Vardhman Mahaveer Medical College and Safdarjung Hospital, New Delhi- 110029, India"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"345","reference":[{"key":"R1","first-page":"346","article-title":"The global burden of typhoid fever","volume":"82","author":"Crump","year":"2004","journal-title":"Bull World Health Organ"},{"key":"R2","doi-asserted-by":"publisher","DOI":"10.1056\/NEJMra020201"},{"key":"R3","doi-asserted-by":"publisher","DOI":"10.1586\/14787210.2013.858019"},{"key":"R4","doi-asserted-by":"publisher","DOI":"10.1086\/375602"},{"key":"R5","doi-asserted-by":"publisher","DOI":"10.1128\/AAC.01288-08"},{"key":"R6","doi-asserted-by":"publisher","DOI":"10.1128\/AAC.00222-06"},{"key":"R7","doi-asserted-by":"publisher","DOI":"10.1093\/jac\/48.5.740"},{"year":"2019","key":"R8"},{"key":"R9","doi-asserted-by":"publisher","DOI":"10.1016\/S1473-3099(17)30753-3"},{"key":"R10","doi-asserted-by":"publisher","DOI":"10.1016\/j.bdq.2015.01.003"},{"key":"R11","doi-asserted-by":"publisher","DOI":"10.1093\/jac\/dkl391"},{"key":"R12","doi-asserted-by":"publisher","DOI":"10.1136\/bmj.333.7563.353-b"},{"key":"R13","doi-asserted-by":"publisher","DOI":"10.1128\/JCM.00456-09"},{"key":"R14","doi-asserted-by":"publisher","DOI":"10.3201\/eid\/1706.101242"},{"key":"R15","doi-asserted-by":"publisher","DOI":"10.3201\/eid1611.100464"},{"key":"R16","doi-asserted-by":"publisher","DOI":"10.1179\/146532805X58085"},{"key":"R17","doi-asserted-by":"publisher","DOI":"10.1086\/516128"},{"key":"R18","doi-asserted-by":"publisher","DOI":"10.1128\/CMR.00016-09"},{"key":"R19","doi-asserted-by":"publisher","DOI":"10.1086\/505397"},{"volume-title":"Clinical and Laboratory Standard Institute. 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