Antimicrobial resistance of commensal Escherichia coli from dairy cattle associated with recent multi-resistant salmonellosis outbreaks

The use of antimicrobial drugs in livestock is suspected to contribute to bacterial antimicrobial resistance (AR) development. Dairy farms experiencing recent outbreaks of salmonellosis involving multi-resistant (MR) Salmonella strains were compared to control farms with respect to AR among bovine commensal E. coli isolates. For most antimicrobials tested, the percentage of AR E. coli isolated from salmonellosis-affected farms was significantly higher than that from control farms. Calf E. coli from both case and control farms had greater levels of AR than cow isolates. Commensal E. coli isolates from case farms and calves tended to more frequently be MR. These data are consistent with the existence of higher antimicrobial selection pressure on farms with recent salmonellosis outbreaks, however, the directionality of the relationship remains to be elucidated. An improved understanding of the epidemiology of AR bacteria in livestock production, both at the herd and molecular level, is essential to mitigate risk to public health and food safety.     

Characterisation of avian pathogenic Escherichia coli (APEC) associated with colisepticaemia compared to faecal isolates from healthy birds

A total of 114 avian pathogenic Escherichia coli (APEC) isolates were collected from cases of colisepticaemia occurring in broilers (77) and layers (37) within Ireland. In addition 45 strains isolated from faeces of healthy birds were included for comparison. All isolates were serogrouped, and examined for known virulence factors, mostly by PCR. The O78 serogroup represented 55 and 27% of broiler and layer colisepticaemic isolates respectively. All isolates were positive for curli fimbriae (crl, csg) and negative for afimbrial adhesin (afa). S-fimbrial (sfa) sequences were present in 8.8% of septicaemic isolates and 8.9% of healthy bird isolates. The majority of E. coli from cases of colisepticaemia (97.4%) and healthy bird (95.6%) isolates were positive for aerobactin (aer), and temperature sensitive haemagglutinin (tsh) was similarly detected in high numbers in 93.9 and 93.3%, respectively. In comparison to E. coli isolates from the faeces of healthy birds, a significantly higher percentage of isolates from septicaemic cases possessed Type 1 fimbriae (fimC) and increased serum survival (iss) gene sequences. Forty-seven (41.2%) isolates from septicaemic birds possessed P-fimbriae (pap) gene sequences, compared with only 15.6% from E. coli isolated from healthy birds. Haemolysin (hlyE) sequences were detected in 46.7% of isolates from healthy birds in comparison with 6.1% of septicaemic isolates. Sequences encoding colicin V (cvaC) were detected in 99.1% of septicaemic isolates and 82.2% of isolates from healthy birds. The K1 capsule was only present in two septicaemic isolates, both taken from layers. Motility was detected in 36.8% of E. coli isolated from cases of septicaemia, compared with 93.3% of isolates from healthy birds. These results demonstrate the presence of 11 virulence genes in E. coli isolated from cases of colisepticaemia within Ireland, and indicate the prevalence of iss and fimC.     

Comparative studies of Bacillus cereus strains isolated from various foods and food poisoning outbreaks.

Certain properties of 22 Bacillus cereus strains isolated from different foods and food poisoning episodes were investigated in order to evaluate possible différences between strains isolated from diarrhoeal and vomiting type food poisoning outbreaks.None of the strains isolated from vomiting type episodes produced acid from salicin and mannose, whereas 80 and 40 % of the strains from diarrhoeal type outbreaks were positive, respectively. No association between the antibiotic sensitivity pattern or the fatty acid composition and the source of a strain could be found, although some strains differed from the general pattern of B. cereus in some instances. No significant differences in the production of the skin factor between strains isolated from the two types of outbreaks were found either. The findings of this study support the observation that the food environment itself essentially affects the enterotoxin formation of B. cereus.     

Comparative genomics analysis of Raoultella planticola S25 isolated from duck in China,with florfenicol resistance

To characterize the florfenicol resistance gene and analyze the structure of the resistance gene-related sequence of an Raoultella planticola strain S25 isolated from a duck fecal sample from a farm in South China. Molecular cloning was performed to clone the resistance genes such as mdfA, floR and so on, and the minimum inhibitory concentrations (MICs) were quantified to determine the resistance levels generated by the cloned genes and the related strains. Sequencing and comparative genomics methods were used to analyze the structure of the resistance gene-related sequence. The result showed that the genome of R. planticola S25 consists of a 5.47 Mb chromosome encoding 4962 predicted coding sequence (CDS) and a 68,566 bp plasmid, pS25-68, encoding 84 ORFs. The plasmid sharing the greatest sequence identity with the floR-carrying plasmid pS25-68 is plasmid1 in Klebsiella pneumoniae strain blaNDM-1, which was isolated from a patient in Canada. The mdfA1 gene encoded on the chromosome generated resistance to florfenicol in addition to chloramphenicol. Comparative genomic analysis of the floR-related transposon-like fragment of pS25-68 showed that an approximately 3 kb sequence encoding IS91-virD2-floR-lysR was conserved and presented in the majority of the sequences (84.5 %, 169/200) collected from the database. The results of this work demonstrated that horizontal transfer of the florfenicol resistance gene floR occurred widely between the bacteria of different species and with different origins and that additional florfenicol resistance genes may be present in the bacterial population.     

Incidence and mobility of R plasmids, Col plasmids and Hly plasmids in E. coli isolated from healthy calves and calves with diarrhea]

Within the set of 200 strains of E. coli isolated from healthy calves and 60 strains of E. coli isolated from calves suffering from diarrhoea we compared the incidence and transfer of determinants of antibioticoresistance, colicinogenesis and hemolytical activity. A significant difference in the incidence and independent mobility of the agents under examination in favour of E. coli from calves suffering from diarrhoea was determined in the case of resistance to chloramphenicol. The increased incidence and independent mobility of the chloramphenicol element in the antibioticoresistent strains of E. coli isolated from calves suffering from diarrhoea can be explained by the three to five-day therapy with a chloramphenicol product.     

Coronaviruses associated with outbreaks of transmissible enteritis of turkeys in Quebec: hemagglutination properties and cell cultivation

Coronaviruses were observed by electron microscopy in the intestinal contents of turkeys in Quebec flocks where repeated outbreaks of enteritis occurred. Three isolates could be serially propagated in turkey embryos inoculated by the amniotic route with clarified intestinal contents. Purification and concentration of viral particles contained in intestinal contents of infected embryos were achieved by precipitation with polyethylene glycol and ultracentrifugation on sucrose density gradients. Three particle types were demonstrated: intact virions with a density of 1.18 to 1.20 g/ml and incomplete particles with densities of 1.14 and 1.24 g/ml. Hemagglutination of rabbit and guinea pig erythrocytes was demonstrated with the intact viral particles; the hemagglutinin was not dependent on incubation temperature. All the isolates were antigenically related, as shown by hemagglutination-inhibition. The turkey coronaviruses did not cross-react with antisera against coronaviruses of avian infectious bronchitis, porcine transmissible enteritis, bovine neonatal calf diarrhea, or mouse hepatitis. One of the Quebec isolates was shown to induce syncytia formation on its third passage in primary chicken-embryo kidney cell cultures. Electron-microscopic examination of infected cell-culture fluids revealed characteristics coronavirus particles identical to those found in intestinal contents of infected turkeys.     

Reports of zoonotic disease outbreaks associated with animal exhibits and availability of recommendations for preventing zoonotic disease transmission from animals to people in such settings

OBJECTIVE: To assess the number of zoonotic disease outbreaks associated with animal exhibits and identify published recommendations for preventing zoonotic disease transmission from animals to people in exhibit settings. DESIGN: Literature review and survey of state public health veterinarians and state epidemiologists. PROCEDURE: MEDLINE and agriculture databases were searched from 1966 through 2000. Retrieved references and additional resources provided by the authors were reviewed. A survey was sent to state public health veterinarians and state epidemiologists to determine whether their states had written recommendations or guidelines for controlling zoonotic diseases in animal exhibition venues, whether their states maintained a listing of animal exhibitors in the state, and whether they had any information on recent outbreaks involving animals in exhibitions. RESULTS: 11 published outbreaks were identified. These outbreaks occurred in a variety of settings including petting zoos, farms, and a zoological park. An additional episode involving exposure to a potentially rabid bear required extensive public health resources. A survey of state public health veterinarians identified 16 additional unpublished outbreaks or incidents. Most states did not have written recommendations or guidelines for controlling zoonotic diseases or any means to disseminate educational materials to animal exhibitors. CONCLUSIONS: Recent outbreaks of zoonotic diseases associated with contact with animals in exhibition venues highlight concerns for disease transmission to public visitors. Only a handful of states have written guidelines for preventing zoonotic disease transmission in animal exhibition venues, and published recommendations currently available focus on preventing enteric diseases and largely do not address other zoonotic diseases or prevention of bite wounds.     

Comparative genomics reveals insights into characterization and distribution of quorum sensing-related genes in Shewanella algae from marine environment and clinical sources

Shewanella algae is not only the most commonly reported species in Shewanella human infections but also capable to inhabit a wide variety of habitats. Although there is evidence that quorum sensing is associated with bacterial adaptation to changing environmental conditions, little is known of the quorum sensing system in S. algae. In this study, we conducted the whole genome sequencing of S. algae strains and applied comparative genomics to reveal the core genome. Genes related to the quorum sensing system were identified by integrated bioinformatics analysis. S. algae harbor genes involved in all three main types of autoinducer systems. This study provides insights into the quorum sensing systems in S. algae, which might be valuable in the future study of cell behavior in S. algae.     

Theileria orientalis MPSP types in Australian cattle herds associated with outbreaks of clinical disease and their association with clinical pathology findings

Between September 2010 and November 2011, 350 EDTA blood samples were received from 73 Australian cattle herds, as cases suspected to be infected with Theileria orientalis. Beef cattle were predominantly affected, with Angus and Angus-crossbred cattle representing 48% of smear positive samples examined. DNA extracts were tested in conventional polymerase chain reaction (PCR) assays for genes encoding the p32, Ikeda, Chitose and Buffeli major piroplasm surface proteins (MPSP). PCR findings were compared with results of clinical pathology examinations of stained blood smears for parasitaemia and packed cell volume (PCV). PCR testing was much more sensitive than clinical pathology examinations in detecting T. orientalis infections, and concurrent testing of neat and diluted extracts gave significantly more PCR positive results than testing of neat extract alone. Significant associations and correlations were shown between PCR results of p32 and Ikeda assays with PCV levels indicative of anaemia, and with the level of parasitaemia estimated by smears. A high proportion of samples had concurrent Ikeda and Chitose infection, and significantly more clinical cases of theileriosis were associated with the Ikeda MPSP type as the sole infection, compared with sole infection with types Chitose or Buffeli. The findings indicate Ikeda type organisms were significantly associated with clinical parameters of theileriosis in cattle herds in eastern Australia, and that this type is most likely to be responsible for outbreaks of theileriosis experienced in affected Australian herds. In New South Wales, 11 of 14 regulatory districts yielded Ikeda positive samples, with five (Mid-Coast, Cumberland, Central North, Hume and Lachlan) containing 234/307 (76%) of the Ikeda positive samples.     

Herd factors associated with the seroprevalences of four major respiratory pathogens in slaughter pigs from farrow-to-finish pig herds

The objective of this study was to investigate sero-epidemiological aspects of Mycoplasma hyopneumoniae (Mh), influenza H1N1 and H3N2 viruses and Aujeszky disease virus (ADV) in fattening pigs from 150 randomly selected farrow-to-finish pig herds. Different herd factors were examined as potential risk indicators for the percentage of pigs with antibodies against the 4 pathogens. The median within-herd seroprevalences of the pathogens were: Mh 76%, H1N1 100%, H3N2 40% and ADV 53%. There was a positive association between the seroprevalences of both influenza viruses, and a negative association between the seroprevalences of ADV and H1N1. The percentage of pigs seropositive for Mh increased with the purchase of gilts and with the season (slaughter date in March-April). The within-herd seroprevalences of both influenza viruses were higher in the case of a higher density of pig herds in the municipality. A higher number of fattening pigs per pen additionally increased the risk of being seropositive for H3N2. The percentage of pigs with anti-gE-antibodies against the wild type ADV increased with higher airspace stocking density in the finishing unit, increasing herd size, increasing number of pig herds in the municipality and slaughter date in March-April. Increased seroprevalences for these 4 respiratory pathogens were mostly associated with pig density in the herd and its vicinity, the winter period, and with the purchase of gilts. Purchase of gilts, number of fattening pigs per pen and airspace stocking density are risk factors that can be managed directly by farmers striving to attain a high respiratory health status of pigs.     

Observations on outbreaks of respiratory disease in calves associated with parainfluenza type 3 virus and respiratory syncytial virus infection.

In four outbreaks of indoor calf pneumonia, dyspnoea was a prominent clinical finding. At necropsy it was associated with pneumonia involving the cranial lobes of the lung and severe pulmonary emphysema. Histological examination of lung tissue revealed bronchiolitis and alveolitis with alveolar epithelial cell hyperplasia and multinucleate syncytium formation. Intraalveolar haemorrhage, intra-alveolar oedema and hyaline membrane formation were also noted. In all cases parainfluenza type 3 (PI3) virus was isolated from the lungs. In each of the four outbreaks there was evidence of PI3 virus and respiratory syncitial virus (RSV) infection.     

Leukocidin genes lukF-P83 and lukM are associated with taphylococcus aureus clonal complexes 151, 479 and 133 isolated from bovine udder infections in Thuringia, Germany

ABSTRACT: Staphylococcus aureus is one of the most important causal agents of bovine mastitis. Population studies on bovine Staphylococcus aureus isolates have identified considerable genetic heterogeneity among strains causing mastitis. The aim of this study was to investigate the contribution of different clonal complexes and the occurrence of virulence factors and resistance determinants within bovine Staphylococcus aureus isolates.A total of 189 Staphylococcus aureus isolates obtained from milk samples of 34 dairy herds in the German Federal State of Thuringia were characterised by microarray technology.The isolates were assigned to eleven different clonal complexes with CC151, CC479 and CC133 being dominant (together 80.5%). The methicillin resistance gene mecA was found in four isolates (2.1%), which belonged to CC398. Enterotoxin genes could be detected in 79.3% of analysed Staphylococcus aureus and 19 isolates (10.1%) harboured a distinct allele of the toxic shock syndrome toxin gene, tst-RF122. The most striking finding of the present study was that almost all except one isolate (151/152) belonging to CC151, CC479 and CC133 harboured the leukocidin genes lukF-P83 and lukM, whereas no further isolates from other lineages possessed these genes.The consistent occurrence of lukF-P83/lukM in the dominating clonal complexes suggests an essential role of this leukocidin in the etiology of bovine mastitis.     

Factors associated with past and potential future use of veterinarians by Ontario trout farmers

This study investigated whether certain variables were associated with Ontario trout farmers' use of the Fish Pathology Laboratory (FPL), Ontario Veterinary College, or their willingness to pay for private veterinary services. Sixty-two farmers, representing 91% of Ontario's 1990 farmed trout production, were personally interviewed. Logistic regression was used to compare the 26 farmers who had submitted fish to the FPL during the previous two years to those who had not. Submitters tended to have been fish farming for fewer years, and to produce more fish, use more workers, treat prophylactically less frequently, keep records of drug treatments, and not disinfect holding units (p<0.05). Most farmers stated they would occasionally hire a private veterinarian. Only 13 farmers anticipated hiring one more than once per year. Polychotomous regression showed that farmers who purchased, instead of hatched, their seed stock, kept records, treated therapeutically often, and used several workers would hire private veterinarians more frequently (p<0.05). Strategies are discussed by which the veterinary profession might better understand and meet the needs of the aquaculture industry.     

Comparative analyses of Pasteurella multocida strains associated with the ovine respiratory and vaginal tracts

Thirty-five isolates of Pasteurella multocida from the vagina and respiratory tract of sheep were compared by analysing their capsular polysaccharide types and outer membrane protein profiles. The phylogenetic relationships of selected isolates with respect to reference strains of P. multocida were also determined by comparative 16S rRNA sequence analysis. Three capsular types, A, D and F, and three major outer membrane protein types were identified, and there were four different combinations of these characteristics which probably marked four individual clones of P. multocida. Strains representing three of these clones were recovered from cases of ovine pneumonia, whereas isolates of the fourth clone were associated exclusively with the vagina of healthy ewes and the liver of a dead septicaemic lamb on the same farm. Analysis of the 16S rRNA sequences showed that there was 100 per cent identity between representative pneumonic isolates and reference strains of P. multocida subspecies galliseptica and P. multocida subspecies multocida. The 16S rRNA genes of representative vaginal and liver isolates from the same farm were identical but differed from the other strains at one nucleotide position, providing strong evidence that the vaginal and liver isolates represent a distinct subpopulation of P. multocida.     

Serum and peritoneal fluid phosphate concentrations as predictors of major intestinal injury associated with equine colic

To determine the reliability with which inorganic phosphorus (phosphate) concentrations can be used to predict major intestinal injury associated with equine colic, phosphate concentrations were measured in serum, peritoneal fluid, or both from 9 clinically normal adult horses (group A), 37 horses successfully managed medically for signs of abdominal pain (group B), 26 horses with signs of abdominal pain and undergoing exploratory laparotomy without intestinal resection (group C), and 26 horses undergoing intestinal resection or euthanasia for extensive intestinal lesions (group D). Peritoneal fluid phosphate concentration was significantly greater in horses in group D (mean, 4.58 +/- 0.34 mg/dl) than in horses in group A (mean, 2.78 +/- 0.21 mg/dl), group B (mean, 2.92 +/- 0.27 mg/dl), and group C (mean, 2.98 +/- 0.28 mg/dl; P less than or equal to 0.01). Serum phosphate concentration was significantly greater in horses in group D (mean, 3.87 +/- 0.30 mg/dl) than in horses in group A (mean, 2.73 +/- 0.22 mg/dl), group B (mean, 2.80 +/- 0.21 mg/dl), and group C (mean, 2.78 +/- 0.22 mg/dl); P less than or equal to 0.05). There was significant (P less than or equal to 0.001) correlation between serum and peritoneal fluid phosphate concentrations within each group and when pairs from all groups were pooled. When peritoneal fluid phosphate concentrations exceeded 3.6 mg/dl, intestinal lesions requiring resection or euthanasia were predicted with sensitivity of 77% and specificity of 76%. When serum phosphate concentrations exceeded 3.3 mg/dl, such lesions were predicted with sensitivity of 60% and specificity of 73%.(ABSTRACT TRUNCATED AT 250 WORDS)