Drug resistance and pulsed-field gel electrophoresis patterns of Lactococcus garvieae isolates from cultured Seriola (yellowtail, amberjack and kingfish) in Japan.
OBJECTIVE
To investigate the existing antimicrobial susceptibility and genetic characteristics of Lactococcus garvieae isolates from cultured Seriola in Japan.


RESULTS
Minimum inhibitory concentrations (MICs) of 14 antimicrobial agents for 170 isolates were determined using the agar dilution method. Seventy-five isolates (44.1%) were simultaneously resistant to erythromycin (EM) (MIC>or=2 microg ml-1), lincomycin (LCM) (MIC>or=128 microg ml-1) and oxytetracycline (OTC) (MIC>or=4 microg ml-1). Resistance to EM was grouped as intermediate- and high-level resistant by MIC values. All resistant isolates possessed ermB and tet(S) genes. The number of different bands between pulsed-field gel electrophoresis patterns of 25 isolates and two ATCC strains (isolated in 1974), determined using two enzymes (ApaI and SmaI), did not exceed 3.


CONCLUSIONS
The present resistance pattern observed with ermB and tet(S) is similar to that observed in previous reports. Moreover, the genetic characteristics of L. garvieae isolates from a wide area in Japan in 2002 and ATCC strains were closely related.


CONCLUSIONS
This study suggests that EM-, LCM- and OTC-resistant isolates have been present for 15 years and that L. garvieae strains with same origin have spread among Seriola spp. in Japan since 1974.
Kawanishi
M
M
National Veterinary Assay Laboratory, Ministry of Agriculture, Forestry and Fisheries, Tokyo, Japan. kawanishi@nval.go.jp
Kojima
A
A
Ishihara
K
K
Esaki
H
H
Kijima
M
M
Takahashi
T
T
Suzuki
S
S
Tamura
Y
Y
D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics; D024881:Drug Resistance, Bacterial / Q000235:genetics*; D016521:Electrophoresis, Gel, Pulsed-Field; D004917:Erythromycin / Q000494:pharmacology; D005398:Fisheries / Q000592:standards; D005399:Fishes / Q000382:microbiology*; D005516:Food Microbiology; D007564:Japan; D017045:Lactococcus / Q000187:drug effects* / Q000235:genetics* / Q000302:isolation & purification; D008034:Lincomycin / Q000494:pharmacology; D008826:Microbial Sensitivity Tests; D010118:Oxytetracycline / Q000494:pharmacology
D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D004917:Erythromycin; D008034:Lincomycin; D010118:Oxytetracycline