| Summary: | Enterococcus species are found in faeces of mammals, birds, insects, reptiles, but also soil, plants and water. These bacteria can also be isolated from animal products such as milk, cheese and meat.
This study was aimed at isolating Enterococcus species from communal and commercial cattle faecal and water samples. A further objective was to determine the antibiotic resistance profiles of the isolates as well as some of the potential factors and mechanisms that could be responsible for their resistance to antibiotics.
A total of 79 cattle faecal and water samples were collected from the communal and commercial farms. Sixty-five faecal samples were collected from commercial (33 healthy and 16 diarrhoeal cattle) and communal (16 healthy cattle) farms. Twelve water samples were collected from the commercial farms and 2 from the communal farm.
From all the samples collected, 129 Enterococcus isolates were identified. Isolates, which included Enterococcus faecium (E. faecium), Enterococcus avium (E. avium), Enterococcus durans (E. durans) and Streptococcus bovis I (Sc. bovis !), were isolated from bovine faeces and water samples, while E. avium was only isolated from water at the communal farm. Furthermore, isolates from the healthy and diarrhoeal commercial cattle included E. faecium, E. avium, E. durans and Sc. bovis I. E. faecium and E. avium species were also isolated from the commercial farm cattle water sources. However, E. faecium was the predominant species in communal cattle faecal and water samples. On the other hand, E. avium was dominant in. commercial cattle faecal and water samples.
Multiple antibiotic resistance (MAR) was observed in enterococci from all samples at both farm types. The predominant MAR phenotype that was prevalent in all enterococci species was GENSMX- NAL-NIT-KAN-STR All isolates showed an MAR index above 0.2 (water; 0.58 to 0.68 and faeces; 0.6 to l. 7). Cluster analysis based on antibiotic inhibition zone diameter data, resulted in dendrograms that showed a similar relationship of Enterococcus isolates from the two farms. Between 13% and 50% of Enterococcus isolates from cattle faeces and water samples from communal and commercial farms were resistant to vancomycin and oxytetracycline. In general, 11% of all the Enterococcus isolates from the cattle faeces was resistant to vancomycin. Thirty one per cent of the isolates from cattle water sources were resistant to both drugs. Vancomycin Resistant Enterococcus (VRE) genes conveying the vanC phenotype were obtained from E. durans and E. avium. This was an unexpected result. The tet A, tet Band tet C genes were not obtained from any of the Enterococcus species.
Further studies on antibiotic resistance should be undertaken especially in rural areas, where farmers could be using over-the-counter medicines such as tetracycline even when it is not necessary. It was speculated in this study that there could be a development of potential reservoirs of antibiotic resistance in farmlands. In order to prevent the distribution of MAR organisms or their transferable resistance genes, a sensible use of antibiotics is necessary in veterinary medicine, animal husbandry and human medicine. === MSc. (Agriculture) North-West University, Mafikeng Campus, 2006
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