Incidence of antibiotic and metal resistance and plasmid Carriage in Aeromonas isolated from brown bullhead (latalurus nebulosus)

Abstract

Seventy-four strains of Aeromonas were isolated from skin, intestine, kidney and liver of 16 brown bullhead (Ictalurus nebulosus). All strains demonstrated multiple antibiotic resistance (MAR) with most strains resistant to rifampin (97O/o), novobiocin (96%) and vancomycin (85%). The minimum inhibitory concentration of eight metals to selected strains of Aeromonas revealed an apparent toxicity of chromium > copper > cadmium > nickel > mercury > zinc > cobalt > lead, based on the percentage of isolates sensitive to each concentration of metal. Plasmid DNA was found in 36% (27) of the isolates and most plasmid-containing strains had multiple plasmids less than 12 kilobase pairs (kbp) in size. No relationship between plasmid content and antibiotic or metal resistance was found. Plasmid incidence in bacteria isolated from five fish indicated that plasmids were more likely to occur in strains isolated from kidney and liver than in strains isolated from skin and intestine.

Antibiotic resistance of Aeromonas hydrophila isolated from marketed fish and prawn of South India

“…This is partially supported by Ansary et al (1992) and Son et al (1997). However, Pettibone et al (1996) have not reported any erythromycin resistant A. hydrophila strains. The variation in the drug resistance may well be related to the source of the A. hydrophila isolates and the frequency and type of antimicrobial agents prescribed for treating Aeromonas infections, e.g.…”

“…All the strains were resistant to methicillin, which was similar to the findings of Motyl et al (1985) who reported that all A. hydrophila strains of human origin were resistant to methicillin. In contrast, Pettibone et al (1996) observed that only 54% of the strains was resistant to this antibiotic. However, Kampfer et al (1999) reported that no significant differences could be observed between clinical and non-clinical Aeromonas isolates, although the clinical isolates showed a few more positive results with respect to antibiotic resistance.…”

“…In contrast, Ramteke et al (1993) have not recorded any polymyxin-B resistant strains. Ramteke et al (1993) and Pettibone et al (1996) have not noticed any Kanamycin resistant strain, whereas the investigation of Ansary et al (1992) supported the existence of kanamycin resistant strains, with a frequency of about 38.2%. About 67% of the A. hydrophila strains obtained from fish and prawn exhibited resistance against trimethoprim (Table 1).…”

“…Chang and Bolton (1987) found that more percentage of Asian isolates of A. hydrophila were resistant to tetracycline and rifampicin than Australian isolates. More than 50% of the A. hydrophila strains was resistant to tetracycline and occurrence of tetracycline resistant strains of A. hydrophila from different sources was reported (Ansary et al, 1992;Ramteke et al, 1993;Pettibone et al, 1996;Son et al, 1997;Kampfer et al, 1999).…”

“…Multiple antibiotic resistance (MAR) among Aeromonas hydrophila strains has been reported from many parts of the world (Pettibone et al, 1996;Son et al, 1997;Ko et al, 1998;Rajeswari Shome and Shome, 1999). Under these circumstances, it will be worthwhile to find out the prevalence of antibiotic resistance of the Aeromonas strains that may be considered as an emerging pathogen and to identify the high-risk source.…”