Occurrence of potentially zoonotic and cephalosporin resistant enteric bacteria among shelter dogs in the Central and South-Central Appalachia.

BACKGROUND: Antimicrobial resistance and presence of zoonotic enteropathogens in shelter dogs pose a public health risk to shelter workers and potential adopters alike. In this study we investigated the prevalence of zoonotic bacterial pathogens and cephalosporin resistant (CefR) enteric bacteria in the feces of apparently healthy shelter dogs in the Cumberland Gap Region (CGR) in the US states of Kentucky, Tennessee and Virginia. RESULTS: Fecal samples of 59 dogs from 10 shelters in the CGR of Central and South-Central Appalachia were screened for the presence of Campylobacter jejuni, Clostridium perfringens, Salmonella and CefR enteric bacteria. C. jejuni, C. perfringens were detected by PCR based assays. Culture and PCR were used for Salmonella detection. Of 59 dogs, fecal samples from 14 (23.7%) and 8 (13.6%) dogs tested positive for cpa and hipO genes of C. perfringens and C. jejuni, respectively. Salmonella was not detected in any of the tested samples by PCR or culture. CefR enteric bacteria were isolated on MacConkey agar supplemented with ceftiofur followed by identification using MALDI-TOF. Fecal samples from 16 dogs (27.1%) yielded a total of 18 CefR enteric bacteria. Majority of CefR isolates (14/18, 77.8%) were E. coli followed by, one isolate each of Enterococcus hirae, Acinetobacter baumannii, Acinetobacter pittii, and Pseudomonas aeruginosa. CefR enteric bacteria were tested for resistance against 19- or 24-antibiotic panels using broth microdilution method. Seventeen (94.4%) CefR bacteria were resistant to more than one antimicrobial agent, and 14 (77.8%) displayed multidrug resistance (MDR). CONCLUSIONS: This study shows that shelter dogs within the CGR not only carry zoonotic bacterial pathogens, but also shed multidrug resistant enteric bacteria in their feces that may pose public health risks.

Metal toxicity in two rodent species and redox potential: Evaluation of quantitative structure-activity relationships.

A quantitative structure-activity relationship study of acute toxicity in the mouse and rat is described for the soluble salts of a relatively large number of metals (between 25 and 30 in total). Electrode potential is the major determinant of acute metal toxicity (R = 0.85 and 0.86) for an intraperitoneal dose in the mouse, whereas the addition of ionic radius and polarizability enables the inclusion of notable outliers in the original expression, such as beryllium and barium, thus giving a good correlation (R = 0.87) with toxicity for 27 metal compounds. These findings are rationalized on the basis of relative ease of ionization, electron affinity, and transport factors of the metals and their ions, thus being consistent with the hard and soft acids and bases properties of metals and their biological reactivities.