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AIMS: The aim of this study was to determine phenotypic and genotypic resistance, virulence and clonal relationship of aeromonads and related species isolated from Czech carp fisheries. METHODS AND RESULTS: Forty-nine isolates obtained from a total of 154 fish from three breeding facilities were species identified using matrix-assisted laser desorption/ionization time of flight and the sequencing of the rpoB housekeeping gene. Most Aeromonas isolates were identified as Aeromonas veronii (94%, n = 34). Susceptibility to six antibiotics (oxytetracycline, flumequine, florfenicol, sulphamethoxazole/trimethoprim, enrofloxacin and oxolinic acid) was tested using the disc diffusion method. The presence of resistance genes and virulence factors was verified by PCR and sequencing, and the clonal relationship was analysed using pulsed-field gel electrophoresis (PFGE). Phenotypic resistance to one or more antimicrobials was found in 32 isolates (65%, n = 49). Resistance to oxytetracycline was the most common (41%) and associated mainly with the presence of tet(E) gene, while the percentage of isolates resistant to florfenicol was low (2%). Isolates carried one to five of the tested virulence factors and showed high diversity of PFGE profiles. CONCLUSIONS: Since the highest percentage of antimicrobial resistance in aeromonads was found for oxytetracycline and the lowest percentage for florfenicol, it is suggested that florfenicol could be an adequate treatment alternative in carp fisheries. SIGNIFICANCE AND IMPACT OF THE STUDY: Increasing resistance of aeromonads to commonly used antimicrobials has become an emerging problem in fisheries. This study was conducted in relation to the practical needs to identify a suitable antibiotic as an alternative to oxytetracycline.
RESUMEN
AIM: The occurrence and epidemiology of extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli in the environment of turkey farms in the Czech Republic were studied. METHODS AND RESULTS: Extended-spectrum beta-lactamase-producing E. coli isolates were found on 8 (20%) of 40 turkey farms surveyed. A total of 200 environmental smears were examined, and a total of 25 ESBL-producing E. coli were isolated. These isolates were analysed using XbaI pulsed-field gel electrophoresis and divided into nine pulsotypes. Most of the isolates harboured the gene bla(SHV-12) on a 40-kb plasmid of the IncFII group with an identical EcoRV restriction profile. Indistinguishable or clonally related SHV-12-producing isolates belonging to the same pulsotypes were found at some unrelated farms. CONCLUSIONS: Widespread occurrence of ESBL-producing E. coli isolates with bla(SHV-12) carried on IncFII plasmids in meat production flocks in the Czech Republic was demonstrated. SIGNIFICANCE AND IMPACT OF THE STUDY: Results indicate vertical transmission of ESBL-producing E. coli within the turkey production pyramid. The study shows the risk of multiresistant ESBL-producing bacteria and antibiotic-resistance genes being transmitted to humans via the food chain.
Asunto(s)
Escherichia coli/enzimología , Carne/microbiología , Plásmidos , Pavos , beta-Lactamasas/genética , Crianza de Animales Domésticos , Animales , República Checa , Electroforesis en Gel de Campo Pulsado , Escherichia coli/genética , Escherichia coli/aislamiento & purificación , Infecciones por Escherichia coli/epidemiología , Infecciones por Escherichia coli/genética , Infecciones por Escherichia coli/microbiología , Proteínas de Escherichia coli/genética , Humanos , Reacción en Cadena de la PolimerasaRESUMEN
AIM: To examine surface water from a pond in the northeastern part of the Czech Republic and young black-headed gulls (Larus ridibundus) nesting on the same pond for the presence of antibiotic-resistant Salmonella and Escherichia coli. METHODS AND RESULTS: A total of 16% (n = 87) of water and 24% (n = 216) of gull samples yielded Salmonella. Salmonella Enteritidis PT8 and PT4 were the most prevalent. Antibiotic resistance was found in 12% (n = 14) of water and 28% (n = 51) of gull salmonellae. Escherichia coli were found in 83 (95%) and 213 (99%) of pond water and gull samples, respectively. Totals of 18% (n = 83) of water and 28% (n = 213) of gull E. coli isolates were resistant to antimicrobial agents tested. Class 1 integrons were found in 21% (n = 14) of water and 15% (n = 60) of gull antibiotic-resistant E. coli isolates. Class 2 integrons and extended-spectrum beta-lactamase-producing E. coli isolates (with bla(CTX-M-1), bla(CTX-M-15)-like, bla(SHV-2) and bla(SHV-12)) were found in 13% (eight positive, n = 60 gull-resistant E. coli isolates) and 3% (seven positive, n = 216 gull E. coli isolates) of gull isolates, respectively. Antibiotic-resistant E. coli isolates with identical pulsed field gel electrophoresis (PFGE) patterns were found in either gulls or water, but not both. Salmonellae of the same serotype and PFGE profile were found in both gulls and water. CONCLUSION: A high prevalence of antibiotic-resistant salmonellae and E. coli were found in both pond water and in sympatric black-headed gulls. SIGNIFICANCE AND IMPACT OF THE STUDY: Intensive contamination of pond surface water by antibiotic-resistant E. coli and salmonellae was documented. Black-headed gulls were identified as important reservoirs of antibiotic-resistant salmonellae and E. coli, including extended-spectrum beta-lactamase-producing isolates.
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Charadriiformes/microbiología , Farmacorresistencia Microbiana , Escherichia coli/efectos de los fármacos , Escherichia coli/genética , Integrones , Salmonella/efectos de los fármacos , Salmonella/genética , beta-Lactamasas/genética , Animales , República Checa , ADN Bacteriano/genética , Reservorios de Enfermedades/veterinaria , Electroforesis en Gel de Campo Pulsado , Escherichia coli/aislamiento & purificación , Pruebas de Sensibilidad Microbiana , Reacción en Cadena de la Polimerasa/métodos , Salmonella/aislamiento & purificaciónRESUMEN
Duck immune sera that are capable of destroying the tolerated skin allografts require the presence of functional host's lymphoid cells for a successful course of the rejection reaction. The effective sera are not able to destroy the grafts in birds surgically bursectomized or thymectomized at hatching. This deficiency can be repaired by thymic, not bursal, implants in bursectomized or thymectomized graft hosts. Similarly, measurements of the radioactivity after application of 125I-labelled gamma globulin to allografted or autografted ducklings confirm a major role of the bursa of Fabricius and thymus in the destruction of the tolerated skin allografts by immune serum.