Detection and analysis of antibiotic resistance variability among Staphylococcus aureus isolates from animal and human sources

Abstract

In consideration of the importance of Staphylococcus aureus regarding its contribution to antibiotic resistance, the present study was designed to find variability among S. aureus isolates in relation to their multidrug resistance patterns. A total of 157 species-specific 23S rRNA based confirmed S. aureus isolates from various clinical and nonclinical animal sources (cattle, buffalo, goat, sheep, dog, camel, pig and horse), human and pieces of meat from butcher shops were included in the present study. Overall more than 95% isolates were recorded resistant to ampicillin and penicillin-G, while approximately 100% isolates were sensitive to chloramphenicol, meropenem and nitrofurantoin. The isolates from different sources showed highly significant (P≤0.01) variation in their resistance patterns for 39 antibiotics, significant variation (p≤0.05) for levofloxacin and nitrofurantoin, and no significant variation (P>0.05) for clindamycin. In Bonferroni correction, human isolates were significantly variable with a p˂0.0001 probability level of variance in relation to other pieces of meat and animal origin sources for most of the antibiotics. Human isolates had the highest (0.40) MAR index. A highly significant difference was observed in the antibiogram pattern between different sources of S. aureus, which may indicate the pattern and frequency of use of various antibiotics in humans and animals.