Prevalence and Antibiogram of Generic Enterococci in Ready-to-Slaughter Beef Cattle

Abstract

Rectal swabs were collected from 95, systematic randomly selected, apparently healthy beef cattle, in order to isolate generic enterococci in Nsukka Southeast, Nigeria, and thus to determine the antibacterial resistance profile of the isolates. Isolation of enterococci was done using Slanetz-Bartley enterococci selective medium. Phenotypic characterization of the isolates to generic level was done following standard biochemical methods. Phenotypic resistance of the isolates to antibacterial agents was determined using the disc diffusion method. From 95 swabs, 93 (97.89%) were positive for enterococci. Of the 93 isolates, 10 (10.75%) were haemolytic Enterococcus species, while 83 (89.25%) were non-haemolytic Enterococcus species. Out of 75 isolates, all (100%) were resistant to cefoxitin, 66 (88%) were resistant to ampicillin, 71 (94%) to amoxicillin/clavulanic acid, 68(90.7%) to ceftriaxone, 42 (56%) to streptomycin, 74 (98.67%) to gentamicin, 16 (21.3%) to tetracycline, 5 (6.7%) to vancomycin, 62 (82.7%) to sulphamethoxazole/trimethoprim, and 1 (1.3%) to chloramphenicol and ciprofloxacin. None of the isolate was resistant to imipenem. The enterococcal isolates exhibited 22 resistance patterns. Out of 75 isolates, 1 (1.3%) isolate was resistant to 1 class of antibacterial agents, 9 (12%) were resistant to 2 classes, and 65 (86.7%) to 3 or more classes. This study has shown that cattle slaughtered in Nsukka Southeast Nigeria are potential reservoirs and disseminators of multidrug-resistant enterococci.