Characterization of antimicrobial resistance of recent Salmonella enterica serovar Gallinarum isolates from chickens in South Korea.
Salmonella enterica serovar Gallinarum isolates (n=105) from chickens in South Korea between 2002 and 2007 were tested for antimicrobial susceptibility by determining minimum inhibitory concentrations of 16 antimicrobials, and their predominant resistance profiles were genetically characterized. Most isolates (99/105; 94.3%) were resistant to nalidixic acid and resistant/intermediately resistant to fluoroquinolones, and 63.8% (67/105) of the isolates were resistant to three or more antimicrobials. Forty-two quinolone-resistant isolates, of which the quinolone resistance-determining regions of the gyrA genes were sequenced, contained a substitution of a Ser to a Phe or Tyr at position 83 (71.4%), or a substitution of an Asp to an Asn, Gly, or Tyr at position 87 (28.6%). Fifty-seven sulphamethoxazole-resistant isolates were tested for the presence of class 1 integrons by polymerase chain reaction, and their resistance gene cassettes were analysed by sequencing. Three different class 1 integrons containing the resistance-gene insert aadA (52.6%; n=30), aadB (12.3%; n=7), or aadB-aadA (12.3%; n=7) were identified. Most isolates harbouring the integron containing aadB-aadA displayed resistance to all three aminoglycosides tested and also showed increased resistance to fluoroquinolones. These findings suggest that fluoroquinolone resistance may be epidemiologically linked to multiple aminoglycoside resistance.
Kang
Min S
MS
National Veterinary Research and Quarantine Service, Anyang, Gyeonggi, South Korea.
Kim
Aeran
A
Jung
Byeong Y
BY
Her
Moon
M
Jeong
Wooseog
W
Cho
Young M
YM
Oh
Jae Y
JY
Lee
Young J
YJ
Kwon
Jun H
JH
Kwon
Yong K
YK
D019943:Amino Acid Substitution; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology / Q000627:therapeutic use; D002645:Chickens / Q000382:microbiology*; D027081:DNA Gyrase / Q000737:chemistry / Q000235:genetics; D017931:DNA Primers; D024881:Drug Resistance, Bacterial; D005998:Glycine; D008826:Microbial Sensitivity Tests; D010641:Phenotype; D011201:Poultry Diseases / Q000188:drug therapy / Q000235:genetics / Q000382:microbiology; D015363:Quinolones / Q000494:pharmacology; D056910:Republic of Korea; D012481:Salmonella Infections, Animal / Q000188:drug therapy / Q000235:genetics / Q000382:microbiology*; D019779:Salmonella enterica / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D012694:Serine; D013420:Sulfamethoxazole / Q000494:pharmacology; D014443:Tyrosine
D000900:Anti-Bacterial Agents; D017931:DNA Primers; D015363:Quinolones; D014443:Tyrosine; D012694:Serine; D027081:DNA Gyrase; D013420:Sulfamethoxazole; D005998:Glycine