Drug resistance and pulsed-field gel electrophoresis patterns of Lactococcus garvieae isolates from cultured Seriola (yellowtail, amberjack and kingfish) in Japan

Abstract

Aims: To investigate the existing antimicrobial susceptibility and genetic characteristics of Lactococcus garvieae isolates from cultured Seriola in Japan. Methods and 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 ≥ 2 μg ml−1), lincomycin (LCM) (MIC ≥ 128 μg ml−1) and oxytetracycline (OTC) (MIC ≥4 μg 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. Significance and Impact of the Study: 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.

Development of a sensitive and specific LAMP PCR assay for detection of fish pathogen Lactococcus garvieae

“…(Kusuda et al 1991), amberjack S. dumerili, kingfish S. lalandi (Kawanishi et al 2005), wild wrasse Coris aygula (Colorni et al 2003), black rockfish Sebastes schlegeli (Kang et al 2004), grey mullet Mugil cephalus (Chen et al 2002) and in giant freshwater prawn Macrobrachium rosenbergii (Chen et al 2001). In addition to aquatic animals, L. garvieae has been isolated from other homoiothermic and poikilothemic animals such as cows, buffalos, cats and dogs (Pot et al 1996, Carvalho et al 1997, Devriese et al 1999.…”

Lactococcosis in Reared Fish in Brazil and Control Strategies

“…Positive results in L. garvieae-specific PCR assay were verified for the five strains, with the amplification of a 1.100 bp fragment. Blast analysis of 16S rRNA sequences of Brazilian isolates presented a 99% similarity in sequences from the L. garvieae Lg2 [13] and ATCC49156 strains, the latter having been previously isolated from diseased fish [14]. In the phylogenetic tree, Brazilian strains were grouped in the same cluster as L. garvieae isolates ATCC49156 and X54262, indicating 100% of bootstrap percentage.…”

“…Among these, only oxytetracycline is allowed in Brazil, and its results are inconstant around the world, such as Japan [18] and Turkey [19]. Antibiotic therapy is not an effective control measure for L. garvieae infection [13,20], and losses can exceed 80% of total production [3]. Application of chemotherapeutic agents is effective under experimental conditions, but is ultimately an unsustainable strategy in the control of lactococcosis due to the development and spread of antibiotic resistance [21].…”

A Transferable 20-Kilobase Multiple Drug Resistance-Conferring R Plasmid (pKL0018) from a Fish Pathogen ( Lactococcus garvieae ) Is Highly Homologous to a Conjugative Multiple Drug Resistance-Conferring Enterococcal Plasmid

“…Moreover, the yellowtail-derived L. garvieae isolates appeared to be homogenous and very different from isolates obtained from other fish, terrestrial animals, and food plants (4,5,6). Recently, of 146 L. garvieae strains isolated from 1999 to 2006 from yellowtail farms in three prefectures in Japan, 46 strains had high levels of resistance to EM, LCM, and tetracycline and were found to be carrying transferable R plasmids that carry ermB and tetS genes, as evidenced by conjugation, Southern blotting, and PCR methods (7).…”

“…Of 170 strains of L. garvieae isolated from cultured Seriola species (yellowtail, amberjack, and kingfish) from nine prefectures in Japan in 2002, most have been reported to have high frequencies of erythromycin (EM), lincomycin (LCM), and oxytetracycline resistance, and all isolates possessed ermB and tetS genes (6). Moreover, the yellowtail-derived L. garvieae isolates appeared to be homogenous and very different from isolates obtained from other fish, terrestrial animals, and food plants (4,5,6).…”