Salmonella enterica serovar typhi: molecular analysis of strains with decreased susceptibility and resistant to ciprofloxacin in india from 2001-2003

Abstract

Chromosomally-mediated reduced susceptibility to ciprofloxacin narrows the therapeutic options in enteric fever. We made a molecular comparison of clinical isolates of fluoroquinolone-resistant strains of Salmonella enterica serotype Typhi from January 2001 to May 2003; 178 isolates were subjected to antimicrobial susceptibility testing by the Kirby-Bauer method of disk diffusion, and agar dilution was used to determine the minimum inhibitory concentration (MIC) to ciprofloxacin. Nalidixic-acid resistant strains (NARST) were observed in 51% of the isolates, of which 98.9% had decreased susceptibility (MIC≥ ≥ ≥ ≥ ≥0.125-1μ μ μ μ μg/mL) to ciprofloxacin. A single strain (4 μ μ μ μ μg/mL) was resistant to ciprofloxacin and double mutations were found in the gyrA gene (76 Asp→ → → → →Asn, 44 leu→ → → → →Ileu). Among seven NARST strains with reduced susceptibility, a single mutation was found in five strains, one of which had 76 Asp→ → → → →Asn and two each had mutations at 87 Asp→ → → → →Asn and 72 Phe→ → → → →Tyr, respectively); no mutations could be detected in two isolates. Routine antimicrobial surveillance, coupled with molecular analysis of fluoroquinolone resistance, is crucial for revision of enteric fever therapeutics.

Increased quinolone resistance among typhoid Salmonella isolated from Egyptian patients

“…We showed that NA resistance increased from 0% in 1993 [16] to 15% in this study, which was similar to what was found (15%) in a report from Vietnam [25] and another (16%) from Japan [26]. However, our data were contradictory to the data reported from Nepal (76% resistance) [27], India (51% resistance) [28], the United States (39% resistance) [29], and South Africa (0.05% resistance) [30]. LEV resistance in our study (7.5%) was lower than that reported in Nepal (73%) [31].…”

Salmonella enterica serovar Typhi and S. Paratyphi A: need to expand the QRDR region?

“…Of the 163 E. coli available sequences in the GenBank databases, we found in all instances Gly 31 , Val 44 , Asp 72 , and Lys 76 . The discrepancies between our results and those reported by Capoor and colleagues [1,6] could be caused by different numbering of the residues because the precursor GyrA protein may be processed into a signal peptide and a functional enzyme. However, this is contradicted by the numbering of the residues, Met 52 , Ser 83 , and Asp 87 , which is in accordance with an unprocessed precursor GyrA protein.…”

In Silico Prediction of Riboswitch and Design of its Inhibitor for Salmonella enterica

“…This bacterium affects human and animals but Salmonella enterica typhimurium strain solely affects human being and there is no animal reservoir [2]. The treatment of typhi fever is done with antibiotics like ciprofloxacine [3], chloramphenicol, quinolone and cephalosporin that target the homologous proteins. Some bacterial strains of salmonella have developed resistance to one or more types of antibiotics that is increasingly becoming a problem with typhoid infections arising from south East Asia.…”