Characterization of Salmonella enterica subsp. enterica serovar Enteritidis Isolates Displaying Quinolone Resistance in Seoul
In order to investigate the resistance patterns and molecular characteristics of resistance gene of 9 NA-resistant Salmonella enterica subsp. enterica serovar Enteritidis, Total of 101 isolates were isolated from stool sampes from 2005 to 2006. Among them, 48 isolates(47.5%) were identified S. Enteritidis, 24 isolates(23.8%) S. Typhi, 8 isolates(42.5%) S. Typhimurium, 7 isolates(6.9%) S. Paratyphi A and 14 isolates (13.9%) others Salmonellas. All of S. Enteritidis were resistant to ampicillin(43.8%), ticarcillin(43.8%), streptomycin(37.5%), chloramphenicol(29.2%), tetracycline(10.4%) and nalidixic acid(18.8%), respectively. All nalidixic acid-resistance isolates represented one point mutation in the quinolone resistance determining region(QRDR) of gyrA gene. Among them, 8(89%) isolates were substituted Tyr for Ser at position amino acid 83th or 1(11%) isolate was substituted Asn for Asp at position amino acid 87th. In consequence, Continued surveillance of NA-resistance among non-Typhi S. entetica isolates is needed to mitigate the increasing prevalence of nalidixic acid resistance.