Antibiotic resistance patterns and detection of blaDHA-1 in Salmonella species isolates from chicken farms in South Korea.
Fifteen nonrepetitive ampicillin-resistant Salmonella spp. were identified among 91 Salmonella sp. isolates during nationwide surveillance of Salmonella in waste from 131 chicken farms during 2006 and 2007. Additional phenotyping and genetic characterization of these 15 isolates by using indicator cephalosporins demonstrated that resistance to ampicillin and reduced susceptibility to cefoxitin in three isolates was caused by TEM-1 and DHA-1 beta-lactamases. Plasmid profiling and Southern blot analysis of these three DHA-1-positive Salmonella serovar Indiana isolates and previously reported unrelated clinical isolates of DHA-1-positive Salmonella serovar Montevideo, Klebsiella pneumoniae, and Escherichia coli from humans and swine indicated the involvement of the large-size plasmid. Restriction enzyme digestion of the plasmids from the transconjugants showed variable restriction patterns except for the two Salmonella serovar Indiana isolates identified in this study. To the best of our knowledge, this is the first report of the presence of the DHA-1 gene among Salmonella spp. of animal origin.
Rayamajhi
Nabin
N
Department of Infectious Diseases, Seoul National University, San 56-1, Kwanak-Ku, Seoul, South Korea. yoohs@snu.ac.kr.
Jung
Byeong Yeal
BY
Cha
Seung Bin
SB
Shin
Min Kyung
MK
Kim
Aeran
A
Kang
Min Su
MS
Lee
Kang Mu
KM
Yoo
Han Sang
HS
D000822:Animal Husbandry; D000818:Animals; D015139:Blotting, Southern; D002645:Chickens; D004269:DNA, Bacterial / Q000032:analysis / Q000235:genetics; D017353:Gene Deletion; D005838:Genotype; D007220:Industrial Waste; D008826:Microbial Sensitivity Tests; D010957:Plasmids / Q000032:analysis; D056910:Republic of Korea; D015183:Restriction Mapping; D012475:Salmonella / Q000187:drug effects* / Q000302:isolation & purification; D018440:beta-Lactam Resistance; D001618:beta-Lactamases / Q000235:genetics*
D004269:DNA, Bacterial; D007220:Industrial Waste; D001618:beta-Lactamases; C494147:beta-lactamase DHA-1, Salmonella