faecalis and E. faecium were resistant to ampicillin. The majority of identified isolates from all samples showed high prevalence of tetracycline
resistance (Tetr) followed by resistance to erythromycin (Eryr)) (Figure 2). High-level resistance to the aminoglycosides streptomycin and kanamycin selleck inhibitor was also detected in E. faecalis, E. faecium, E. hirae and E. casseliflavus from all samples (Figure 2). In general, the antibiotic resistance profiles of enterococci isolated from pig feces, selleck products cockroach feces, and the digestive tract of house flies were similar and no significant differences were observed within the same bacterial species (Figure 2). However, significant differences in resistance to ciprofloxacin and streptomycin were detected in E. faecalis (Figure 2A). Likewise, the incidence of ciprofloxacin resistance in E. faecium from the digestive tract of house flies was significantly higher compared to E. faecium from feces of German cockroaches and pigs (Figure 2B). Figure 2 Phenotypic antibiotic resistance profiles (%) of (A) E. faecalis , (B) E. faecium , (C) E. hirae and (D) E. casseliflavus isolated from pig feces, German cockroach feces, and the digestive tract of house flies collected on two swine farms. AMP = ampicillin, VAN
= vancomycin, TET = tetracycline, CHL = chloramphenicol, CIP = ciprofloxacin, ERY = erythromycin, STR = streptomycin, KAN = kanamycin. The most common combination or resistance traits was Tetr and Eryr (E. faecalis, 65.8%; E. faecium, 52.0%; E. hirae, 34.5%; E. casseliflavus, 51.1%), followed selleck chemical by the combination of Tetr, Eryr, Strr, and Kanr (E. faecalis, 6.4%; E. faecium, 17.6%; E. hirae, 8.8%; E. casseliflavus, 17.0%). Further, the prevalence of the most common two-antibiotic-resistant isolates (Tetr and Eryr) was not significantly different in the feces of pigs and cockroaches
and in the digestive tract of house flies (P = 0.0816). Similarly, no significant differences (P = 0.0596) in the prevalence of multiple-antibiotic-resistant isolates (Tetr, Eryr, Strr, and Kanr) were observed among all samples (pig feces, 11.9%; cockroach feces, 10.7%; house flies, 7.5%). The prevalence of resistance genes (expressed as percentages) within each Enterococcus spp. is presented in Figure 3. The results revealed that the Plasmin tet (M) and erm (B) determinants were widespread, tet (S), tet (O) and tet (K) were rare, and tet (A), tet (C), tet (Q) and tet (W) were not detected from the isolates tested based on our PCR approach. Irrespective of their origin, the majority of identified isolates contained the tet (M) determinant followed by the erm (B) determinant (Figure 3). Significant differences in prevalence of the tet (M) determinant were detected in enterococci isolated from pig and cockroach feces and the digestive tract of house flies (Figure 3).