Similarity of Tetracycline Resistance Genes Isolated from Fish Farm Bacteria to Those from Clinical Isolates

Abstract

Tetracycline-resistant (Tet r ) bacteria were isolated from fishes collected at three different fish farms in the southern part of Japan in August and September 2000. Of the 66 Tet r gram-negative strains, 29 were identified as carrying tetB only. Four carried tetY, and another four carried tetD. Three strains carried tetC, two strains carried tetB and tetY, and one strain carried tetC and tetG. Sequence analyses indicated the identity in Tet r genes between the fish farm bacteria and clinical bacteria: 99.3 to 99.9% for tetB, 98.2 to 100% for tetC, 99.7 to 100% for tetD, 92.0 to 96.2% for tetG, and 97.1 to 100% for tetY. Eleven of the Tet r strains transferred Tet r genes by conjugation to Escherichia coli HB-101. All transconjugants were resistant to tetracycline, oxycycline, doxycycline, and minocycline. The donors included strains of Photobacterium, Vibrio, Pseudomonas, Alteromonas, Citrobacter, and Salmonella spp., and they transferred tetB, tetY, or tetD to the recipients. Because NaCl enhanced their growth, these Tet r strains, except for the Pseudomonas, Citrobacter, and Salmonella strains, were recognized as marine bacteria. Our results suggest that tet genes from fish farm bacteria have the same origins as those from clinical strains.Many different kinds of antibiotics have been used as therapeutic agents in aquaculture in Japan. Intensive work was done until the 1980s to develop guidelines for antibiotic usage in fish farms. The guidelines regulated doses and required a period of drug-free rearing before sale of fish and succeeded in keeping the residual antibiotics in cultured fish to nondetectable levels. However, Samuelsen et al. (35) found that antibiotic-resistant bacteria persisted in fish farm sediments for at least 18 months after chemotherapy. Since the products of aquaculture are consumed by humans and since many antibiotic resistance determinants are encoded by transferable plasmids, cultured fish may serve as a vehicle for transmission of antibiotic resistance to bacteria that are commensal or pathogenic to humans (34).Tetracyclines are among the therapeutic agents most commonly used in human and veterinary treatment. Oxytetracycline is permitted to be mixed with feed for fish, and food sanitation law in Japan permits certain residual levels in fish. Because of the widespread use of tetracycline, resistance to it has been disseminated to many species of marine bacteria (4,6,18,42,46).More than 30 different kinds of tetracycline resistance determinants have been published. Resistance genes have been mainly categorized into two major groups, those responsible for proton-dependent efflux of tetracycline (24) and those conferring ribosomal protection by cytoplasmic proteins (9). Dissemination of the proton-dependent tetracycline efflux protein in aquaculture environments has been reported (5,12,13,14,22,34,37). Previous work has identified the relevant genes by using DNA hybridization or PCR methods (4,12,13,14,15,16,27,28,34,37), but the nucleotide sequences of these determinants remain unkn...

Antifungal activity of Stenotrophomonas maltophilia in Stomoxys calcitranslarvae

“…(PALLERONI;BRADBURY, 1993;OLIVEIRA-GARCIA et al, 2002), can be found in a variety of geographical regions, environments and decomposing organic materials (rivers, wells, reservoir lakes, soil, raw milk, frozen fish, eggs, animal carcasses, hospital equipment and environment, semen, frozen bovine embryos, human anatomical sites and urine) (KONEMMAN et al, 2001;ALMEIDA et al, 2005). It has also been reported in goats and crocodiles (HARRIS; ROGERS, 2001) and in fish like Seriola quinqueradiata (FURUSHITA et al, 2003) and Ictalunes punctatus (DU et al, 2011). Depending on the strain isolated, it may have pathogenic activity against both humans and animals (CHANSANG et al, 2010).…”

“…The purified PCR products were sequenced directly using the sequencing primers 27f (AGA GTT TGA TCC TGG CTC AG) (FURUSHITA et al, 2003); 108r (CAG ATT CCC ACG CGT TAC GC) and 420r (TTA CAA CCC TAA GGC CTT C) (LEYS et al, 2004); Amp2 (AAG GAG GTG ATC CAR CCG CA) (WANG et al, 1996); 16S1203f (GAG GTG GGG ATG ACG TCA AGT CCT C); and 16S1110r (TGC GCT CGT TGC GGG ACT TAA CC) (SOARES-RAMOS et al, 2003).…”

Similarity in the Structure of <i>tetD</i>-Carrying Mobile Genetic Elements in Bacterial Strains of Different Genera Isolated from Cultured Yellowtail

“…Since many antibiotic resistance genes are encoded by transferable elements including plasmids and transposons, cultured fish may serve as a vehicle for transmission of antibiotic resistance to bacteria that are commensal or pathogenic to humans Rhodes et al, 2000 . In our previous study at three different fish farms A, B, and C located in the southern part of Japan Furushita et al, 2003 , we confirmed the presence of conjugative plasmids conferring the resistance to tetracycline, kanamycin and chloramphenicol in four bacteria of three different genera, isolated from cultured yellowtails collected at fish farm A and C. Each fish farm was separated from each other by over 100 km and no reliable data on antibiotic use were obtained from the fish farmers Furushita et al, 2003 . The tetracycline-resistance gene was identified as tetA D Allard et al, 1993 .…”

Diazotrophic bacteria associated to sugarcane varieties cropped at Northeast Region of Brazil

“…The 16S rRNA gene was amplified by PCR using primers 27F (5'-AGAGTTTGATCCTGGCTCAG-3 ') in combination with 1492R (5'-TACGG(C/T)TACCTTGTTACGACTT-3') or a combination of two primers, 27f and Amp2R (5'-ACMC AAGGAGGTGATCCARC-3 ') (Heuer et al, 1997;Furushita et al, 2003) min, 60 °C -1 min and 72 °C -2 min and a final extension step at 72 °C -4 min. PCR products were analyzed by electrophoresis in 2 % agarose gel and purified using the kit Wizard® SV Gel and PCR Clean-Up System (Promega).…”