Fifteen isolates of Escherichia coli obtained from the blood and tissues of septic foals had plasmid DNA of size ranging from 2.5 to 93 megadaltons. These isolates grew in normal equine serum (serum resistant), a trait previously documented to be expressed by isolates obtained from blood and tissues of septic foals, but not by isolates obtained from the feces of clinically normal horses. Of these isolates, 3 contained conjugal plasmids that encoded resistance to multiple antimicrobial agents linked to serum resistance and, in 1 isolate, to production of aerobactin as well. Serum resistance and production of aerobactin are related to virulence of septicemic E coli from non-equine sources.

A model of bovine pneumonic pasteurellosis, using an indwelling bronchial catheter for inoculation and subsequent lavage of a single main stem bronchus of the lung, was evaluated in a preliminary efficacy trial of an experimental therapeutic compound, Inoculation of 10(7) Pasteurella haemolytica organisms into the bronchus consistently induced a focal pneumonic lesion with typical morphology of pneumonic pasteurellosis in the left or right caudal lung lobe. The experimental treatment caused significant (P < 0.05) reduction in lung lesion volume, compared with that of a saline-treated control. It also caused significant (P < 0.05) reduction in lavage fluid bacterial counts at 48 hours after inoculation, compared with counts in the controls. The inflammatory cell count and the percentage of neutrophils increased markedly in lavage fluids 8 hours after inoculation, but differences were not detected between treatments. Significant differences between treatments were not found in clinical signs, rectal temperature, or histologic changes. This model appears to be a sensitive indicator of treatment efficacy and has the advantage over previous models of pneumonic pasteurellosis of allowing sequential monitoring of the primary lesion site.

Candida species are a natural component of the intestinal tract microflora, but in favourable conditions they can cause superficial, mucosal, or even systemic candidiasis. Poultry production might be a source of human drug-resistant yeast infections, including Candida spp. The limited data concerning the antifungal susceptibility of poultry Candida isolates prompted us to carry out research to determine the susceptibility of isolates from turkey intestinal tracts. The beak cavity, crop and cloaca were swabbed of 580 turkeys from 58 flocks in western Poland. The susceptibility tests were conducted using the E-test method with amphotericin B, fluconazole, itraconazole, and voriconazole on 52 isolates of C. albicans, C. catenulata, C. glabrata, C. palmioleophila, C. rugosa, C. krusei and C. lusitaniae. All isolates were susceptible to voriconazole. According to the MIC values obtained for amphotericin B and fluconazole, all Candida spp. isolates were classified as susceptible according to the described breakpoints except for C. krusei, which was the only isolate that was amphotericin B-, fluconazole- and itraconazole-resistant. The susceptibility to itraconazole varied: 11 of the Candida isolates were susceptible (21.1%), 29 were dose-dependently susceptible (55.8%), and 12 isolates were resistant (23.1%). There are few resistant strains of Candida in turkeys, and the drug resistance varies. When Candida passes from turkeys to humans, there is a wide range of antifungal treatment options.

Bovine subclinical mastitis was one of the most important health problems facing dairy industry, its impact exceeded the economic aspects and extended to potential negative effects on human health. The current study aimed to determine the prevalence of E. coli as an important mastitic pathogen and identify some of its most important virulence gene as well as their antimicrobial resistance profile. In the present study E. coli was isolated and biochemically identified whereas out of 100 subclinically mastitic milk samples was nine samples were positive for E. coli with 9% prevalence rate. Serotyping of these isolates declared that 3 isolates were serotype O26:H11, 2 isolates in serotype O91:H21 and 1 isolate in each of serotypes O55:H7, O128:H2, O146:H21 and O124. Antimicrobial resistance profile of the obtained isolates showing that all the isolates were 100% resistant to both erythromycin and streptomycin, while 88.9% (8/9) were sensitive to gentamicin. The presence of 3 important virulence factors including shiga toxin1(stx1), shiga toxin 2 (stx2) and intimin (eae) genes, among the obtained isolates was reported using PCR. Molecular investigation revealing that 2 isolates contain all studied virulence genes (stx1, stx2 and eae), 3 isolates contain (stx1 and stx2), while stx1 was detected solely in 2 isolates, also 1 isolate contain only stx2 and lastly 1 isolate was negative for any of the studied virulence factors. In a conclusion, there was a 9% prevalence rate of E. coli in subclinically mastitic milk samples in the current study, indicating its importance as a mastitic pathogen. The shiga toxin genes (stx1 & stx2) are widely distributed among E. coli isolates, while the intimin (eae) gene is less prevalent in comparison to shiga toxin genes. Also the recorded high multidrug resistance rate among the isolates posing threat to human health though entrance of these strains into the human being food chain whereas the isolated E. coli strains had the highest resistance to erythromycin and Streptomycin (100%), followed by Clindamycin (77.8%), Nalidixic acid (66.7%), and Gentamicin (11.1%) was the lowest.

Specimens collected from various pyogenic lesions of dogs were culturally examined for staphylococci and all staphylococcal isolates obtained from the specimens were also tested for susceptibility to 14 antimicrobial agents. A total of 123 isolates of staphylococci were identified. Of these, 120 were Staphylococcus intermedius and 3 were S aureus. All isolates were susceptible to oxacillin, cefazolin, cephalothin and amikacin, whereas more than 85% of the isolates were resistant to ampicillin, penicillin G and tetracycline. S intermedius isolates could be divided into 8 different biotypes by biotyping with the most common type accounting for 66.7% of the isolates.

Campylobacter is the most common bacterial cause of gastroenteritis globally. A total of 182 fully identified strains of Campylobacter species (42 C. coli and 140 C. jejuni) collected from 6 broiler farms were subjected to studying the antimicrobial resistance pattern and molecular typing of virulence (cadF, ctdA, dnaJ waaC,iam, and fla) and antimicrobial resistance genes (blaOXA-61, gyrA, tetA, tetO, and IR) with sequencing of gyrA region of one strain of fluroquinolones resistant C. coli and C. jejuni. The identified isolates were highly resistant to erythromycin and sulfamethoxazole-trimethoprim. Furthermore, both meropenem and imipenem were effective against the recovered isolates. The tested C. jejuni and C. coli strains had 100%, 83.3%, and 83.3% prevalence of cadF, ctdA, and dnaJ virulence genes, respectively, while waaC, iam, and fla genes couldn’t be detected. The blaOXA-61 resistance gene was found in all of the Campylobacter spp. examined. Furthermore, gyrA, tetA, tetO, and IR resistance genes were found in 100%, 83.3%, 83.3%, and 66.7% of the retrieved C. jejuni strains, respectively.  Likewise, resistance genes were found in 83.3%, 83.3%, 83.3%, and 66.7% of the retrieved C. coli strains, respectively. Approximately 58% (7/12) of the Campylobacter spp. recovered were MDR. Furthermore, 50% (3/6) of the C. jejuni strains recovered were MDR, while 66.7% (4/6) of the C. coli isolates recovered were MDR with MARI(0.22-0.55). For detection of mutations of the gyrA gene, the sequence data of two isolates (C. jejuni and C.coli) were analyzed against the reference sequence on the gene bank where the C. jejuni strain had six mutations, while the C. coli strain had twenty-three. The current findings suggest that MDR Campylobacter strains in poultry may be able to transmit highly virulent Campylobacter as a foodborne pathogen.

This study was conducted to compare the patterns of mastitic pathogens and the antimicrobial susceptibility of Staphylococcus (S.) aureus from conventional milking (CM) and robotic milking (RM) dairy herds. To accomplish this, the minimum inhibitory concentrations of 14 antimicrobial agents were tested against S. aureus by the microdilution method. Regardless of the milking system, S. aureus, coagulase negative staphylococcus, and Streptococcus uberis were isolated. Additionally, significant differences in the antimicrobial susceptibility of S. aureus isolates between RM and CM farms were only observed in response to tetracycline.

In this study, trends in the sales of antimicrobials for use in livestock facilities and fisheries from 2003 to 2012 were investigated with regard to antimicrobial group, antimicrobial usage, and animal species. The overall amount of antimicrobials sold each year from 2003 to 2007 was 1,500 tons, after which they decreased, with the lowest sales being 936 tons in 2012. The total volume of antimicrobials used for feed additives decreased markedly by 94% from 2003 to 2012, which was mainly attributed to banning of feed additives. However, antimicrobial consumption through self prescription by farmers for disease prevention and treatment increased by 25% from 2003 to 2012. The largest volume of antimicrobials sold was for use in pigs (48~57%), followed by poultry (18~24%), fisheries (11~25%), and cattle (5~8%). Tetracycline was the highest selling antimicrobial, followed by penicillins and sulfonamides, although the overall sale of all three antimicrobials gradually decreased over the study period. This study demonstrated that the total consumption of antimicrobials has gradually decreased since 2008. Nevertheless, usage by nonprofessionals increased, which can ultimately cause emergence and spread of antimicrobial resistance. Thus, early establishment of veterinary prescription guidelines for prudent use of antimicrobials is urgently needed in Korea.