Ceftiofur sodium

The aim of the experiment was to evaluate under controlled conditions the impact on the excretion of 3GC-resistant Escherichia coli of the injection of one-day-old chicks with ceftiofur, a third-generation cephalosporin (3GC). Three isolators containing specific-pathogen-free chicks were used. In the first one, 20 birds were injected with ceftiofur then ten of them were orally inoculated with a weak inoculum of a 3GC-resistant E. coli field isolate containing an IncI1/ST3 plasmid encoding a blaCTX-M-1 beta-lactamase. The other chicks were kept as contact birds. None of the 20 birds in the second isolator were injected with ceftiofur, but ten of them were similarly inoculated with the 3GC-resistant strain and the others kept as contact birds. A third isolator contained ten non-injected, non-inoculated chicks. Fecal samples were collected regularly over one month and the E. coli isolated on non-supplemented media were characterized by antimicrobial agar dilution, detection of selected resistance genes and determination of phylogenetic group by PCR.

Aerococcus viridans has been reported as a human and animal pathogen causing urinary tract infection, arthritis, pneumonia, meningitis and endocarditis. Routinely, A. viridans is not surveyed in clinical diagnosis laboratories and commonly is misidentified as other bacteria. There is no concrete data on the prevalence and impact of the pathogen to both human and animal health. In the present study, we report the isolation and molecular and antibiotic susceptibility characterization of A. viridans strains from porcine urinary infections. A total of 22 isolates were identified as A. viridans by MALDI-TOF MS and confirmed by 16S rRNA gene sequencing. Isolates were genotyped by single enzyme amplified fragments length polymorphism (SE-AFLP) that resulted in 19 clusters of which 81.2% were composed by single isolates. The high genetic heterogeneity corroborates previous studies and appears to be a particularity of A. viridans. The minimal inhibitory concentration (MIC) values also presented variability especially for ceftiofur, fluoroquinolones and aminoglycosides.

We compared the occurrences of 3rd-generation cephalosporin-resistant (3GCr), tetracycline-resistant (TETr), and trimethoprim-sulfamethoxazole-resistant (COTr) Escherichia coli, 3GCr and nalidixic acid-resistant (NALr) Salmonella enterica, and erythromycin-resistant (ERYr) enterococci from the fecal samples of ceftiofur-treated (n = 162) and nonantimicrobial-treated (n = 207) comingled beef cows ≥8 years old, for which complete antimicrobial treatment records were available. The prevalence of 3GCr (17%; n = 369), TETr (88%), COTr E. coli (22%), and ERYr enterococci (69%) was not significantly (p > 0.05) associated with ceftiofur treatment, prior history of other antimicrobial treatments, or duration of time between last antimicrobial treatment and sampling. 3GCr and NALr S. enterica were not detected. The prevalence of tetB was significantly (p < 0.05) higher compared with tetA among TETr E. coli. However, the prevalence of tetA was significantly (p < 0.

The prevalence of Salmonella spp. was investigated in 109 wild birds poached in the illegal wildlife trade in Rio de Janeiro; most of them are passerines from Thraupidae family and three from Psittacidae. One strain of Salmonella ser. Typhimurium and two strains of Salmonella ser. Panama were isolated from passerine species and all of them showed resistance to multiple antimicrobial drugs, like ampicillin, ceftriaxone, ceftiofur, tetracycline, gentamicin, nalidixic acid, ciprofloxacin, and enrofloxacin. PFGE showed 100% similarity among the Salmonella ser. Typhimurium strain isolated from a Temminck's seedeater (Sporophila falcirostris) and the strains isolated from a human outbreak, in southern Brazil. The two Salmonella ser. Panama strains isolated from two chestnut-capped blackbirds (Chrysomus ruficapillus) present in the same catch showed the same clonal origin and have never been associated with epizooties and human outbreaks. Potential for dissemination of resistant Salmonella through situations offered by captive management and the isolation of the same strain from wild birds and human sources may become a problem for the conservation of natural populations and to public health.