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Objectives: Antimicrobial drugs are frequently administered in veal calves, but investigations on associations with antimicrobial susceptibility of bacteria are scarce and convey partly contradictory findings. The aim of this study was to investigate associations of antimicrobial use (AMU) during the fattening period with antimicrobial susceptibility shortly before slaughter.Methods: Detailed treatment data of 1905 veal calves from 38 farms were collected prospectively during monthly farm visits for 1 year (n = 1864 treatments, n = 535 visits); 1582 Escherichia coli, 1059 Pasteurella multocida and 315 Mannheimia haemolytica were isolated from rectal and nasopharyngeal swabs collected before slaughter and subjected to antimicrobial susceptibility testing by microdilution. Associations of antimicrobial treatments with resistant isolates were investigated at the calf level.Results: Associations of AMU with antimicrobial resistance were observed using generalized linear models. For E. coli, the odds of being resistant were increased with increased AMU (OR 1.36 when number of treatments >1, P = 0.066). Use of tetracyclines was associated with resistance to tetracycline (OR 1.86, P < 0.001) and use of penicillins was associated with resistance to ampicillin (OR 1.66, P = 0.014). No significant associations were observed for P. multocida (use of aminoglycosides: OR 3.66 for resistance to spectinomycin, P = 0.074). For M. haemolytica, the odds of being resistant were increased with increased AMU (OR 4.63, P < 0.001), and use of tetracyclines was associated with resistance to tetracycline (OR 6.49, P < 0.001).Conclusions: Occurrence of resistant bacteria shortly before slaughter was associated with AMU in veal calves. Prudent and appropriate use may contribute to limit the selection of resistant bacteria on veal farms. [ABSTRACT FROM AUTHOR]

Toxoplasma gondii is the agent of toxoplasmosis, which is common to both humans and cattle. That is why the goal of work was to study the spreading of the agent of toxoplasmosis among cattle in certain regions of Ukraine, which in turn will make it possible to predict the appearance of the disease among people and prevent the development of its clinical signs. Whole blood or serum samples of cattle of different ages and sexes from farms in Kyiv, Zhytomyr, Khmelnytskyi and Lviv regions of Ukraine were sent to the laboratory for research. The presence of total antibodies to T. gondii was determined in the serum of the animals. To do this, we used the method of enzyme-linked immunosorbent assay using test kits from different manufacturers in accordance with the guidelines. In general, the prevalence of T. gondii among cattle in Kyiv, Zhytomyr, Khmelnytskyi and Lviv regions of Ukraine according to the results of studies was 10.3% (95% confidence interval: 6.7-15.1). At the same time, the study of animals was carried out in two stages, in 2014 and 2018, and the prevalence did not differ significantly. Thus, in 2014, according to the results of research, a positive reaction to the agent of toxoplasmosis was detected in 10 samples or 13.9% (95% confidence interval: 7.3-23.4), while in 2018 this figure was 11 samples or 8.4% (95% confidence interval: 4.5-14.1) of the studied animals. Also, in 2014 and 2018 studies found that the highest level of seroprevalence of the agent of toxoplasmosis in both years of research was registered in cattle from farms of Zhytomyr and Kyiv regions was 11.9% (95% confidence interval: 4.5-24.4) and 11% (95% confidence interval: 5.9-18.3), respectively. During the conducted research, an increase in the prevalence of T. gondii with the age of animals was statistically significant. Among animals under six months of age, of the 65 serum samples tested, 3 tested positively to the agent (4.6; 95% confidence interval: 1.2-12.1), while in the group of animals older than three years (49 cows) 10 samples were positively responded (20.4; 95% confidence interval: 10.9-33.4) compared to the previous group of animals, the P-value was 0.0114. So, the data obtained indicate the presence of the agent of toxoplasmosis among cattle in Ukraine, which requires further study and development of approaches to prevent human infection when eating meat and dairy products of positively reacting animals [ABSTRACT FROM AUTHOR]

Aim: Cattle is one of the main sources of food supply chain for humans in most countries. The present study aimed to identify the infection rates for Toxoplasma gondii, Neospora caninum, and Sarcocystis spp. by polymerase chain reaction (PCR) method in native slaughtered cattle in Kashan, central Iran. Materials and Methods: Totally, 159 diaphragm, esophagus, and muscle samples (53 samples of each) were collected from native beef cattle from Kashan slaughterhouse, central Iran. The genomic DNA was extracted, and PCR method was used separately for detection of N. caninum, Sarcocystis, and T. gondii species using specific primers. Finding: Sarcocystis was found in 84.9% of muscles, 83% of esophagus, and 84.9% of diaphragm samples. Mixed infection (Sarcocystis cruzi–Sarcocystis hominis) was the most common infection, followed by S. cruzi and S. hominis. Sarcocystis hirsuta was not detected in any samples. T. gondii was detected only in three (5.7%) out of the 53 muscle tissues samples of cattle. N. caninum was found in 18.9% of muscles, 24.5% of esophagus, and 28.3% of diaphragm samples. One of the cattle had coinfection to Neospora, Toxoplasma, and Sarcocystis in muscles simultaneously. There was no statistically significant difference between infection rates and age as well as sex in each organ. Conclusion: This study revealed a low prevalence rate of T. gondii, but a high prevalence of infection to N. caninum and S. cruzi or mixed infection of S. cruzi with S. hominis among slaughtered cattle. Prevention measures such as keeping away dogs from cattle grazing are recommended. [ABSTRACT FROM AUTHOR]

Species of the genus Sarcocystis are recognized as protozoan parasites infecting a wide range of animals, including humans. This study aimed to provide data on the occurrence, genetic characterization, and epidemiological significance of Sarcocystis spp. in cattle destined for human consumption in Romania. A total of 117 heart samples from slaughtered cattle in three southwestern Romanian counties (Dolj, Timiș, and Gorj) were analyzed in order to detect sarcocysts, using fresh examination microscopic techniques. Subsequently, the isolated sarcocysts and/or cyst fragments (5–15 per sample) from each infected animal were molecularly characterized. Overall, 17.9% (21/117) of the tested animals were found to be Sarcocystis spp. positive by microscopy. Genetic characterization of Sarcocystis spp. isolates, based on sequence analysis of the 18S rRNA gene, showed the presence of a single species, namely S. cruzi. No correlation was found (p>0.05) between S. cruzi infection and the origin, age, breed, and gender of cattle, but the grazing farming system was positively associated (p=0.031) with the pathogen prevalence and can be considered a risk factor (OR = 3.6) in acquiring infection. To evaluate the possible public health risk, further investigation focused on the processing of other Sarcocystis-specific tissue matrices and evidence of human infections is recommended. This is the first study of bovine Sarcocystis infection in Romania. [ABSTRACT FROM AUTHOR]

Objectives: To explore the dynamics of faecal ESBL/AmpC shedding in dairy cattle and farmers, a study was conducted to examine changes in shedding by individual animals, as well as environmental exposure, and to study the association between antimicrobial use (AMU) and ESBL/AmpC shedding.Methods: The study comprised a cross-sectional survey of 20 farms and a 1 year follow-up of 10 farms. Faecal samples were cultured by both direct inoculation on MacConkey agar + 1 mg/L cefotaxime (MC+) and enrichment in LB-broth + 1 mg/L cefotaxime with subsequent inoculation on MC+. Dust samples were collected using electrostatic dustfall collectors (EDCs). Human faecal samples were collected by the farmers. Presence of ESBL/AmpC genes was screened for by PCR and sequencing. Using mixed effects logistic regression, ORs were determined and population-attributable fractions (PAFs) calculated subsequently.Results: In Phase 1, 8/20 farms were positive for ESBL/AmpC and, with 2 negative farms, were selected for Phase 2. Transient shedding of dominant allele variants was observed in the animals. EDCs and human faecal samples did not reflect what was observed in the animals. AMU was related to shedding of ESBLs in the next sampling moment [OR 14.6 (95% CI 3.0-80.0)] and the PAF of AMU was 0.36 (95% CI 0.08-0.77). Calves fed with colostrum from cows on dry-off therapy was not a risk factor [OR 1.7 (95% CI 0.7-4.9, P = 0.28)].Conclusions: The presence of ESBL/AmpC could only be partly explained by AMU. No link was shown between shedding in cattle and humans or the environment. Interventions should focus on prevention of introduction. [ABSTRACT FROM AUTHOR]

Disease incidence is intimately associated with an animal's commensal bacteria populations (microbiome), as microbes that are involved with morbidity and mortality are commonly found in animals with no sign of disease. An understanding of the animal's resident respiratory pathogens, in the upper nasal cavity prior to weaning, may help us to understand the impact of these pathogens on incidence of respiratory disease. For this research, the overall goal was to characterize bacterial populations associated with calves at an early age and through time periods prior to weaning in 3 herds at the U.S. Meat Animal Research Center. Nasal swabs from the upper nasal cavity were collected at initial vaccination (approximately 40 d of age), preconditioning (approximately 130 d of age), and weaning (approximately 150 d of age) in 2015 and 2016. DNA was extracted from nasal swabs and combined into 2 pools of 10 animals for each sampling time point, in each herd, for a total of 6 pools at each sampling time point and 18 pools for all sampling time points within each year. To evaluate and compare the microbiome of each pooled sample, hypervariable regions 1 through 3 along the 16S ribosomal RNA (rRNA) gene were amplified by PCR and sequenced using next-generation sequencing (Illumina MiSeq) for identification of the bacterial taxa present. Alpha and beta diversity were also measured. Overall, microbial communities were different between combinations of sampling year, herd location, and sampling time prior to weaning as shown by beta diversity. Analysis of these specific respiratory pathogens prior to weaning will present a clearer picture of the distribution of microbial populations in animals prior to weaning and not exhibiting clinical signs of respiratory disease. Therefore, evaluation of the animal's resident bacterial populations in the upper nasal cavity during different phases of the beef production system may help us to understand the impact of the microbiome on incidence of respiratory disease in cattle. [ABSTRACT FROM AUTHOR]

This study aimed to molecular investigation the prevalence of Theileriaannulataparasite that isolated from blood samples of cattle. A hundred of blood sampleswascollected randomanly from cattles ofthe middle area of Iraq (Babylon province). Samples were submitted to blood DNA extraction assay. Nano drop spectrophotometer and QRT-PCR with TaqMan methods were involved for the surface antigen Tams1detection of Theileriaannulata. Real- Time PCR results showed only 16 samples were positive out of 50 blood samples with a percentage 32%. The threshold cycle (CT value) of these positive samples were ranged from CT: 24.29 to CT: 35.69. The Real-Time PCRefficiency was validated using standard curve method, and the efficiently was approximately (99.9%).Surprisingly, the overall results from current study showed there were no association between ages, gender. Infectionsdistribution between (1-12month) (28.57%), 1-2 year (31.57%) and 3-10 year (29.4%).Additionally, the ratio of the infected females at age of 1-2yearswere twice more than the ratio of infected males. [ABSTRACT FROM AUTHOR]

Natural transference of maternal microbes to the neonate, especially at birth via the vaginal canal, has recently been recognized in humans and cows; however, its microbial influence on calf health has not yet been documented. We compared the bacterial communities in vaginal and fecal samples from 81 pregnant dairy cows versus those in nasopharyngeal and fecal samples collected at 3, 14 and 35 days of life from their respective progeny. The microbiota of the calf upper respiratory tract (URT), regardless of calf age, was found to be highly similar to the maternal vaginal microbiota. Calf fecal microbiota clustered closely to the maternal fecal microbiota, progressing toward an adult-like state over the first 35 days when relative abundances of taxa were considered. Sixty-four, 65 and 87% of the detected OTUs were shared between cow and calf fecal microbiota at days 3, 14 and 35 respectively, whereas 73, 76 and 87% were shared between maternal vaginal microbiome and calf URT microbiota at days 3, 14 and 35, respectively. Bacteroidetes, Ruminococcus, Clostridium, and Blautia were the top four genera identified in maternal and calf fecal samples. Mannheimia, Moraxella, Bacteroides, Streptococcus and Pseudomonas were the top five genera identified in maternal vaginal and calf URT samples. Mannheimia was relatively more abundant in the vaginal microbiota of cows whose progeny were diagnosed with respiratory and middle ear disease. Our results indicate that maternal vaginal microbiota potentially influences the initial bacterial colonization of the calf URT, and that might have an important impact on the health of the calf respiratory tract and middle ear. [ABSTRACT FROM AUTHOR]

The beef cattle industry represents a significant portion of the USA's agricultural sect, with beef cattle accounting for the most red meat consumed in the USA. Feed represents the largest input cost in the beef industry, accounting for approximately 70% of total input cost. Given that, novel methods need to be employed to optimize feed efficiency in cattle to reduce monetary cost as well as environmental cost associated with livestock industries, such as methane production and nitrogen release into the environment. The rumen microbiome contributes to feed efficiency by breaking down low-quality feedstuffs into energy substrates that can subsequently be utilized by the host animal. Attempts to manipulate the rumen microbiome have been met with mixed success, though persistent changes have not yet been achieved beyond changing diet. Recent technological advances have made analyzing host-wide effects of the rumen microbiome possible, as well as provided finer resolution of those effects. This manuscript reviews contributing factors to the rumen microbiome establishment or re-establishment following rumen microbiome perturbation, as well as host-microbiome interactions that may be responsible for possible host specificity of the rumen microbiome. Understanding and accounting for the variety of factors contributing to rumen microbiome establishment or re-establishment in cattle will ultimately lead to identification of biomarkers of feed efficiency that will result in improved selection criteria, as well as aid to determine methods for persistent microbiome manipulation to optimize production phenotypes. [ABSTRACT FROM AUTHOR]

Objectives: To investigate the prevalence and molecular characteristics of ESBL-producing Escherichia coli (ESBL-EC) in faecal samples from dairy cows in China.Methods: In total, 651 faecal samples were collected from cows distributed among the 10 provinces of China. Potential ESBL-EC isolates were cultured on selective medium. The clonal relatedness of the ESBL-EC isolates was assessed using MLST. WGS was conducted on 3 mcr-positive isolates and 14 additional randomly selected ESBL-EC isolates. Southern blot, S1-PFGE and conjugation were performed for mcr-1-carrying isolates. The genetic environment of the pMCR-JLF4 plasmid was also analysed.Results: In total, 290 unique ESBL-EC isolates were detected from 284 cows (43.6%). Alleles of CTX-M were observed in 94.1% (273/290) of all isolates. The most prevalent genotypes observed in this study were blaCTX-M-14, blaCTX-M-15, blaCTX-M-17 and blaCTX-M-55. Differentiation of 79 STs with a polyclonal structure was accomplished using MLST. Clonal complex 10 was the most prevalent major complex detected here. Furthermore, the mcr-1 gene was detected in three isolates. The complete sequence of the mcr-1-containing pMCR-JLF4 was determined. The plasmid was 66.7 kb in length, with a genetic structure of nikA-nikB-mcr-1-pap2. Conjugation analysis confirmed that the mcr-1 gene in pMCR-JLF4 was transferable without the assistance of the ISApl1 gene.Conclusions: The data presented here suggest high prevalence of ESBL-EC in Chinese cow farms. Furthermore, it was clearly demonstrated that commensal E. coli strains can be reservoirs of blaCTX-M genes, potentially contributing to the dissemination and transfer of the mcr-1 gene to pathogenic bacteria among cows. [ABSTRACT FROM AUTHOR]

The diverse rumen microbiome converts lowquality feedstuffs into usable energy and provides approximately 70% of the energy required by its ruminant host through fermentation byproducts. Due to microbial impacts on host health and productivity, numerous studies have associated rumen microbiome variation with important sustainability phenotypes, such as feed efficiency and methane emissions. Although diet, genetics, and environment contribute to variation in feed efficiency, selection for feed-efficient beef cattle using genetic improvement technologies has helped to understand and improve the persistence and longevity of such phenotypes within the herd. While diet has been considered to be the primary driver for the composition and structure of the rumen microbiome, recent studies have indicated the microbial communities present in the rumen are under low-to-moderate host genetic control. The mutualistic, commensal, and parasitic microorganisms that reside in the rumen and lower gastrointestinal tract of cattle and other ruminants exert enormous influence over animal physiology and performance. The ability to interrogate these systems at great depth has permitted a greater understanding of the microbiological and molecular mechanisms involved in ruminant nutrition and health. The work in our group in the field of beef cattle gut microbiology, as it relates to feed efficiency, permits the exploration of these critical microbial community networks. This knowledge will aid researchers seeking to address the grand challenge of maintaining host-efficient gut microbiomes throughout cattle production operations. This work is supported by the Agriculture and Food Research Initiative grant no. 2020-67015-30832 from the USDA National Institute of Food and Agriculture. [ABSTRACT FROM AUTHOR]

The research aimed to identify the bacteria present in the reproductive tract of dairy cattle at follicular and luteal phases of the estrus cycle. Seven samples of cervical mucus were each obtained from the reproductive tract, at follicular and luteal phase, of fourteen healthy cattle, 2-3 years of age, with body condition scores of 2.0-8.3. Sporet, motility, triple sugar iron agar, mannitol and glucose tests were done to obtain gram characteristics and bacterial morphology, which enabled identification at the genus level. Non-specific bacteria isolated at follicular phase were Staphylococcus (50%), Corynebacterium (25%) and Escherichia (25%). At luteal phase, Staphylococcus (45.5%), Escherichia (45.5%) and Corynebacterium (9%) were isolated. The results suggest that a number of bacteria can be found in the reproductive tract of dairy cattle, both at follicular phase and luteal phase. [ABSTRACT FROM AUTHOR]

This research was done to evaluate the characteristics and probiotic potential of lactic acid bacteria (LAB) isolated from the small intestine of ten three year-old male Ongole crossbred cattle. Ten-centimeter samples were obtained from each small intestine, wastes were removed then samples were placed in sterile sample bottles, and immediately taken to the laboratory for bacterial isolation. The LAB isolates were subjected to low pH tolerance (pH 2 and 4), bile salt resistance, and antimicrobial activity against enteric pathogens Staphylococcus aureus and Eschericia coli. Biochemical assay indicated that isolate was gram positive, rodshaped, catalase negative, and capable of fermenting glucose, mannitol, xylose, rhamnose, sucrose, lactose, arabinose, raffinose and sorbitol. Biochemical and morphological identification suggests that the isolate was Lactobacillus plantarum WPL 117 (strain number of control indicator organisms was Lactobacillus plantarum ATCC 14917). This isolate was able to survive at low pH (2 and 4), tolerated 0.3% bile salts, and capable of inhibiting S. aureus and E. coli. Thus, this isolate can be considered a probiotic candidate for further study. [ABSTRACT FROM AUTHOR]

Highlights • PCR and culture performance was evaluated for Staph. aureus and Strep. agalactiae. • The sensitivity was higher for PCR than bacterial culture for milk and teat skin. • The specificity of PCR and bacterial culture was generally high. • Different target conditions of culture and PCR probably affected the results. Abstract Streptococcus agalactiae (Strep. agalactiae) and Staphylococcus aureus (Staph. aureus) are originally regarded as contagious mastitis pathogens, however, both pathogens have recently been isolated from extramammary and environmental sites, indicating that other sites than the udder might contribute to the spread of these pathogens potentially causing intramammary infections. Diagnostic tools to identify pathogens at extramammary sites are available but still needs to be validated. The objective of this cross-sectional field study was to estimate the diagnostic sensitivity (Se) and specificity (Sp) of the commercially available Mastit4 qPCR assay and bacterial culture (BC) in identifying Strep. agalactiae and Staph. aureus from milk and teat skin samples. We randomly selected 30–40 cows with high somatic cell counts from eight Danish Strep. agalactiae- positive dairy herds with automatic milking systems. Teat skin samples and aseptic milk samples were collected from right rear quarters (n = 287) for BC and PCR analysis. Se and Sp were estimated in a Bayesian latent class analysis. For milk samples, the Se and Sp of qPCR for Strep. agalactiae were estimated to 0.97 and 0.99, respectively, whereas the Se and Sp of BC were 0.41 and 1.00, respectively. The Se and Sp of qPCR for Staph. aureus were estimated to 0.95 and 0.99, respectively, whereas the Se and Sp of BC were 0.54 and 0.77, respectively. For teat skin samples, the Se and Sp of qPCR for Strep. agalactiae were estimated to be 0.97 and 0.96, respectively, whereas the Se and Sp of BC were 0.33 and 1.00, respectively. The Se and Sp of qPCR for Staph. aureus were estimated to 0.94 and 0.98, respectively, whereas the Se and Sp of BC were 0.44 and 0.74, respectively. In conclusion, the Se for diagnosing Strep. agalactiae and Staph. aureus IMI was higher for qPCR than BC, suggesting that qPCR is a valuable method for detecting both pathogens from quarter-level milk samples. The performance of BC in the detection of Strep. agalactiae and Staph. aureus on teat skin was poor compared to qPCR, indicating that differences in the target condition of the two methods should be considered when implementing them as routine diagnostic tests for detecting teat skin colonisers. The low Se of BC may preclude the use of BC for skin testing, and qPCR is better for this task. [ABSTRACT FROM AUTHOR]

Abstract: Cattle are a major reservoir of Shiga toxin‐producing Escherichia coli. This study investigated the occurrence of seven major STEC serogroups including O157, O145, O103, O121, O111, O45 and O26 among 578 STEC isolates previously recovered from 559 cattle. The isolates were characterized for serotype and major virulence genes. Polymerase chain reaction revealed that 41.7% (241/578) of isolates belonged to STEC O157, O145, O103, O121, O45 and O26, and 33 distinct serotypes. The 241 isolates corresponded to 16.5% (92/559) of cattle that were STEC positive. The prevalence of cattle that tested positive for at least one of the six serogroups across the five farms was variable ranging from 2.9% to 43.4%. Occurrence rates for individual serogroups were as follows: STEC O26 was found in 10.2% (57/559); O45 in 2.9% (16/559); O145 in 2.5% (14/559); O157 in 1.4% (8/559); O121 in 1.1% (6/559); and O103 in 0.4% (2/559). The following proportions of virulence genes were observed: stx1, 69.3% (167/241); stx2, 96.3% (232/241); eaeA, 7.1% (17/241); ehxA, 92.5% (223/241); and both stx1 and stx2, 62.2% (150/241) of isolates. These findings are evidence that cattle in South Africa carry STEC that belong to six major STEC serogroups commonly incriminated in human disease. However, only a subset of serotypes associated with these serogroups were clinically relevant in human disease. Most STEC isolates carried stx1, stx2 and ehxA but lacked eaeA, a major STEC virulence factor in human disease. [ABSTRACT FROM AUTHOR]

Objectives: To elucidate the phylogenetic relationships among ST9-MRSA-XII isolates from different sources and their genetic features in colonization of different hosts.Methods: We obtained whole-genome sequences of two ST9-MRSA-XII isolates from nasal swabs associated with live pigs in China, and compared them with 135 previously sequenced genomes of 78 human-associated, 39 bovine and 18 porcine Staphylococcus aureus consisting of 11 MRSA of SCCmecXII, 62 MRSA of other SCCmec types and 62 MSSA. The distribution of diverse mobile genetic elements (MGEs), resistance genes and virulence determinants was investigated in relation to isolate phylogeny. Comparisons of SNPs and small insertion/deletions (indels) were conducted to examine genome-level variation between porcine and bovine ST9-MRSA-XII.Results: Phylogenetic analysis revealed that both of our porcine ST9-MRSA-XII isolates clustered with porcine, bovine and human-associated ST9-MRSA-XII. All of these isolates possessed a novel type V pathogenicity island, νSaα, carrying the von Willebrand-binding protein gene vwb, the immune evasion complex gene scn, the aminoglycoside resistance gene aadE, staphylococcal superantigen-like genes (ssl1-ssl11) and lpl tandem genes. Compared with bovine ST9-MRSA-XII BA01611, our porcine isolates contain non-synonymous nucleotide substitutions in genes encoding adhesins and an indel located in a phosphonate ABC transporter pseudogene.Conclusions: The data suggest transmission of ST9-MRSA-XII among swine, cattle and humans. The extraordinary success of the ST9-MRSA-XII group in colonization of various hosts is likely due to acquisition of many MGEs harbouring functional antimicrobial resistance and virulence genes. Transmission of ST9-MRSA-XII between porcine and bovine hosts was accompanied by changes in binding profile and function in genes involved in metabolism. [ABSTRACT FROM AUTHOR]

The goal of this study was to compare the molecular features of bovine- and human community-acquired extended-spectrum β-lactamase (ESBL)-producing Escherichia coli in Israel. Bovine ESBL-producing E. coli were isolated during a point-prevalence study from the main farming locations throughout Israel. Human ESBL-producing E. coli isolates were collected from community-acquired urinary tract infection cases. Molecular typing was done initially by repetitive extragenic palindromic-PCR. Representative isolates were subjected to next-generation sequencing (NGS) and analyzed for multilocus sequence typing (MLST), core genome MLST (cgMLST), bla CTX-M gene allele, and mobile genetic elements (MGEs) surrounding it. Out of the 287 bovine- and 104 community-derived ESBL-producing E. coli isolates, 44 and 26 isolates were subjected to NGS, respectively. Both populations exhibited a diverse but distinct clonal structure with predominance of several sequence types (STs); two clones, ST-10/167 ( n  = 13) and ST-38 ( n  = 8), were present. cgMLST analysis of these clones revealed that the majority of isolates exhibited phylogenetic distance (PD) of >178 gene difference from their closest isolate, with the exception of five isolates that exhibited PD of <24 gene difference, including two bovine- to three community-derived isolates. Hence, clonal transmission of ESBL-producing E. coli between cattle and the community, although uncommon, is likely to have occurred. The bla CTX-M-15 gene was identified in 52/70 (74%) isolates from both cattle and the community and was surrounded by MGEs that were composed mostly of either the Tn 3 or IS 1380 families. Thus, MGEs are likely to play an important role in the exchange of resistance genes. [ABSTRACT FROM AUTHOR]

The aim of this study was to compare the antimicrobial resistance profiles of top five enterohemorrhagic Escherichia coli (EHEC) and enteropathogenic E. coli (EPEC) to E. coli isolated from the fecal flora of the same adult cattle. Previous prevalence studies had led to the isolation by immunomagnetic separation (IMS) of 39 EHEC and 80 EPEC. Seven EHEC were resistant (17.9%), and six were multidrug resistant (MDR) (15.4%). None of the top five EHEC was resistant to azithromycin. Nine EPEC O26:H11 (11.3%) were resistant. They were all resistant to tetracycline, and four were MDR (5.0%). An E. coli strain was isolated from the feces (without preselection by IMS) of 97 bovine carriers of top 5 strains. All these strains were susceptible to antibiotics. Comparative analyses did not reveal any differences between the cytotoxic activities of resistant EHEC and their susceptible counterparts or in the production of attachment and effacement lesions. These results highlighted the higher percentage of resistance of EHEC and EPEC strains compared to other E. coli. They also showed that resistance traits did not have any impact on the expression of virulence phenotypes in EHEC strains. [ABSTRACT FROM AUTHOR]

Livestock microbiota is becoming a focus of interest for veterinaries, animal nutritionists and microbiologists in view to select beneficial bacteria with impact in health and animal productivity. As resident adapted microorganisms, lactic acid bacteria (LAB) were isolated, identified and characterized from the homologous host to promote their permanence/efficiency acting as additives in feedlot cattle feeding. Cultivable LAB numbers from cattle feces (CF), pens soil (PS) and feed rations (FR) ranged from 5 to 6 log CFU/g during feedlot permanence. Isolates (500) were identified by (GTG) 5 -PCR and sequence analysis of 16S rRNA, being represented by Enterococcus, Lactobacillus, Leuconostoc, Pediococcus and Weissella genera and 20 different species. Genetic mapping showed that predominant LAB species in CF and PS samples were Lactobacillus (Lb) mucosae (34%), Enterococcus (E) hirae (26%) and E. faecium-durans (20%), while in FR E. faecium-durans (46%), Pediococcus (P). pentosaceous, P. acidilactici (17%) and Lb. acidophilus (11%) were mainly isolated. Surface characterization showed most of LAB as high hydrophilic, however several strains from CF and PS revealed strong hydrophobic and auto-aggregative character with a positive correlation between both superficial properties. Adhesion to polystyrene displayed variable biofilm formation patterns for Enterococcus and Lactobacillus strains depending on the presence of Tween in MRS medium. When antagonistic activity of isolated LAB against bovine relevant pathogens was evaluated, organic acids and hydrogen peroxide production were mostly responsible for inhibition; bacteriocin production was shown only by a Lb. mucosae strain. In addition, tolerance to acid and bile salts showed lactobacilli to withstand GIT conditions, while enterococci were more sensitive to low acid environment. On these bases, several Lactobacillus strains may be selected to explore their potential use as direct fed bacteria in feedlot cattle. [ABSTRACT FROM AUTHOR]

Between 2009 and 2016, 317 and 529 swabs from cattle and pig carcasses, respectively, were collected all over Poland and tested for the presence of Campylobacter. Among 37 (11.7%) and 161 (30.4%) positive samples, 44 Campylobacter jejuni isolates were detected. A total of 29 different sequence types (STs) and 12 various clonal complexes were identified. Antimicrobial resistance revealed that 17 (38.6%) C. jejuni (10 from cattle and 7 from pig carcasses, respectively) were susceptible to all antimicrobials used in the study, whereas the remaining 27 (61.4%) isolates (12 from cattle and 15 from pigs, respectively) were resistant to at least one antimicrobial agent, mainly to quinolones (23 out of 44 isolates; 52.3%) and tetracyclines (14 strains; 31.8%). Only one isolate from cattle and two from pigs displayed resistance to streptomycin, and none of C. jejuni tested was resistant to erythromycin and gentamicin. All isolates with STs, ST356, ST443, ST464, ST658, ST2036, and ST6411, as well as some isolates belonging to ST257 and ST1947, were resistant to quinolones and tetracyclines. The results show that cattle and pigs may be a reservoir of quinolone and tetracycline resistant C. jejuni with STs which were previously isolated from humans with campylobacteriosis. [ABSTRACT FROM AUTHOR]

The effect of different pathogens was studied by evaluating the contralateral (healthy and infected) mammary quarters of 146 lactating cows. The impact of SM on economic return (quarter milk yield × milk price) was determined by applying milk payment estimates on milk collected from healthy vs. infected glands. Cows were considered infected when they had at least 2 out of 3 weekly composite SCC results > 200 × 10 3 cells/mL and a microbiological culture ( MC ) positive result from composite foremilk samples, collected in the third week of sampling. Infected cows were evaluated a second time within 15 days and had milk yield measured at the quarter level and foremilk samples collected by aseptic technique for analysis of MC, milk composition and SCC. Of the 611-composite milk samples, 397 (65%) were culture-negative, and 214 (35%) were culture-positive and the most frequent isolated bacteria were Corynebacterium spp. (7.9%), coagulase negative staphylococci (5.8%), Staphylococcus aureus (5.3%), Streptococcus uberis (4.6%), Streptococcus agalactiae (3.9%), other environmental streptococci (2.4%), Gram-negative isolates (2.4%), Enterococcus spp. (1.4%) and Streptococcus dysgalactiae (0.7%). A total of 55 pairs of healthy contralateral quarters (control) were compared, and no difference was observed between them when evaluating SCC, milk yield, fat and protein concentration and economic return. A total of 124 pairs of healthy had lower SCC (274.9 × 10 3 cells/mL) than infected contralateral quarters (SCC of 1038.5 × 10 3 cells/mL). At the quarter level, IMI caused by minor pathogens had no effect on SCC, milk yield and economic return. Subclinical mastitis caused by contagious and environmental pathogens increased SCC and decreased milk yield when compared with healthy contralateral quarters. Moreover, quarters infected by contagious pathogens had increased concentrations of milk protein and fat when compared with healthy contralateral quarters. Therefore, the milk economic return was lower in quarters with SM caused by environmental pathogens (US$ 0.18/quarter.milking) and contagious (US$ 0.22/quarter.milking) when compared with healthy contralateral quarters. The milk losses ranged from 0.07 kg/quarter.milking to 1.4 kg/quarter.milking and the economic losses ranged from US$ 0.02–0.4/quarter.milking according to the pathogen causing SM. [ABSTRACT FROM AUTHOR]

Urea has been used in diets of cattle as a non-protein nitrogen source. It is hydrolyzed to ammonia, which can be used for microbial protein synthesis. Use of metabolomics methodologies to study the rumen microbial and host blood metabolic profiles induced by urea nitrogen has not been previously characterized. The objective of this study was to identify changes in rumen microbial and plasma metabolite profiles in dairy cows after urea supplementation using a nuclear magnetic resonance (NMR)-based untargeted quantitative metabolomic approach. Six dairy cows with rumen fistulas were randomly assigned to two groups used in a two period cross-over trial and each experimental period lasted 21 days. All the cows were fed the same total mixed rations, but were intraruminally supplemented with 180 g urea per cow daily or not during the experimental period. Rumen fluid and blood samples were collected and analyzed using nuclear magnetic resonance spectroscopy and multivariate analysis of variance. Differences in rumen and plasma metabolite concentrations in cows from the two groups were assessed using orthogonal partial least-squares discriminant analysis and identified by searching against related databases. Concentrations of valine, aspartate, glutamate, and uracil in the rumen, and urea and pyroglutamate in the plasma, were higher ( P  < 0.05) in the urea-supplemented group than in the control group. Metabolic pathway analysis of the affected metabolites revealed that pantothenate and CoA biosynthesis, beta-alanine metabolism, valine, leucine, and isoleucine metabolism in the rumen, and urea and glutathione metabolism in the plasma were significantly increased by urea nitrogen. The levels of aspartate and glutamate in the rumen correlated strongly ( P  < 0.01) with the level of urea in plasma. These findings provided novel information to aid understanding of the metabolic pathways affected by urea nitrogen in dairy cows, and could potentially help to guide efforts directed at improving the efficiency of urea utilization in the rumen. [ABSTRACT FROM AUTHOR]

Several multiple-media culture systems have become commercially available for on-farm identification of mastitis-associated pathogens. However, the accuracy of these systems has not been thoroughly and independently validated against microbiological evaluations performed by referral laboratories. Therefore, the purpose of the present study was to evaluate the performance of commercially available culture plates (Accumast, Minnesota Easy System, SSGN and SSGNC Quad plates) to identify pathogens associated with clinical mastitis in dairy cows. Milk samples from the affected quarter with clinical mastitis were aerobically cultured with the on-farm culture systems and by two additional reference laboratories. Agreeing results from both standard laboratories were denoted as the reference standard (RS). Accuracy (Ac), sensitivity (Se), specificity (Sp), positive and negative predictive values (PPV and NPV, respectively) and Cohen’s kappa coefficient (k) of on-farm plates were determined based on the RS culture of 211 milk samples. All four plate-systems correctly identified ≥ 84.9% of milk samples with no bacterial growth. Accumast had greater values for all overall predictive factors (Ac, Se, Sp, PPV and NPV) and a substantial agreement (k = 0.79) with RS. The inter-rater agreements of Minnesota, SSGN, and SSGNC with RS were moderate (0.45 ≤ k ≤ 0.55). The effectiveness to categorize bacterial colonies at the genus and species was numerically different amongst the commercial plates. Our findings suggest that Accumast was the most accurate on-farm culture system for identification of mastitis-associated pathogens of the four systems included in the analysis. [ABSTRACT FROM AUTHOR]

Two experiments were carried out to evaluate the bactericidal impacts of Bacillus amyloliquefaciens CECT 5940 on the shedding of faecal pathogenic bacteria in dairy calves (Experiment 1) and in adults dogs (experiment 2). In the calves experiment, a completely randomized design was used to investigate the faecal bacteria profile of Holstein dairy calves fed with either pasteurized waste milk (PWM; n = 9) or a formulated non-medicated milk replacer (NMR; n = 9) for 60 d. The NMR containing sodium-butyrate and the active probiotic B. amyloliquefaciens CECT 5940. In the dogs experiment, addition of same probiotic (i.e., B. amyloliquefaciens CECT 5940) was carried out in two stages. The first stage started from day 7–37, and the second from day 44–71. The assessment of faecal score measured on day 22, 37, 42, 57, 71 and 77 to determine the texture of the stools. Calves received PWM consumed (P < 0.05) more starter feed between day 16 and day 45. The calves fed NMR had more moisture faeces and less cough reflux than the PWM-calves. Feeding NMR to calves increased faecal Klebsiella oxytoca and Proteus vulgaris counts in comparison to PWM-calves. The administration of B. amyloliquefaciens CECT 5940 to the dog diet has no significant effect on the hardness of the stool. Meanwhile, the bacillus count increases while the coliforms count decreases upon B. amyloliquefaciens CECT 5940 administration. This reveals that B. amyloliquefaciens CECT 5940 survived the gastrointestinal passage and rapidly colonized the dog intestine, which could positively affect the metabolism and composition of the intestinal microflora. These results show that B. amyloliquefaciens are a promising probiotic with an antimicrobial and bactericidal activities against the intestinal pathogenic bacteria for dairy calves and adult dogs. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the efficacy of the association of the nematophagous fungi (Duddingtonia flagrans-AC001); (Pochonia chlamydosporia-VC4) and (Arthrobotrys robusta-I31) in a pelletised formulation of a sodium alginate matrix. The viability and activity of pellet germination and fungal activity (after encapsulation) were evaluated usingin vitroandin vivotests. Next, 12 heads of cattle, Dutch mestizo x zebu, with an average age of 12 months were dewormed with an anthelmintic. Next, 20 days after treatment with the anthelmintic, the animals were randomly divided into two groups of six animals each, and placed in two paddocks with 7.0 ha each ofBrachiaria decumbenswith historical grazing by animals naturally infected by gastrointestinal nematode parasites. At first, each animal was treated with 2 g of pellets per 10 kg of animal, containing the associated fungi (AC001 + VC4 + I31) administered twice a week in conjunction with commercial feed. Each animal in the control group received 2 g of pellets without mycelia added to the feed. The percentage reduction of infective larvae in thein vitrotest was 94% (p < .01). In thein vivotest, the treated animals with fungal association had lower egg counts per gram of faeces (p < .01) compared to the control group animals – a reduction of 91.8%. The reduction in the number of infective larvae recovered from the pasture was 27.5% at a distance of 0–20 cm from the stool bulk, and 26.7% at a distance of 20–40 cm. This association (AC001 + VC4 + I31) of nematophagous fungi was effective in nematode control. [ABSTRACT FROM AUTHOR]

The paper presents the study of the habitat of mycobacteria in various natural and climatic zones of the Karaganda region, which showed that out of all the isolated cultures, 307 (94.5%) were atypical mycobacteria (M. scrofulaceum, M. avium). At that, 64.5% of atypical mycobacteria cultures (M.scrofulaceum, M. avium) were isolated from the diagnostic material and objects of the external environment of the steppe zone.Thesensitinsfrom epizootic strains of mycobacteria were tested in terms of such criteria as sterility, safety, reactogenicity, lack of sensitizing properties, activity, and specificity. The sensitinswere administered to guinea pigs and cattle using an intradermal needless syringe. Preliminary experiments on guinea pigs found that sensitins had biological and specific activity, identical to avian purified protein derivative tuberculin. The tests of developed sensitinsM. Scrofulaceumand M. avium on 59 cattle showed that the sensitins were highly effective in differentiating nonspecific reactions and demonstrated the expedience of their application.Using sensitins for lifetime differentiation of nonspecific reactions to tuberculin mammalian in healthy animals and cattle recovering from tuberculosis prevents the premature slaughtering of commercially valuable animals of a reproductive age. [ABSTRACT FROM AUTHOR]

Current information on prevalence and antimicrobial resistance (AMR) of bacterial respiratory pathogens is crucial to guide antimicrobial choice for control and treatment of bovine respiratory disease (BRD). The objectives were to describe the prevalence of three BRD-associated bacteria ( Mannheimia haemolytica , Pasteurella multocida , and Histophilus somni ) in the lower airways of feedlot cattle, and to analyze AMR in these bacteria. Cattle with (n = 210) and without (n = 107) BRD were sampled by trans-tracheal aspiration at four feedlots (Nov. 15–Jan. 16). These cattle had received 2.5 mg/kg of tulathromycin on arrival at the feedlot for BRD control and two in-feed pulses of chlortetracycline (5 g/animal/day for 5 days) within the first 21 days on feed to prevent histophilosis. Bacteria were detected by culture and AMR was tested by microdilution. Pasteurella multocida was the most frequent bacterium isolated in cattle with BRD (54.8%), followed by M. haemolytica (30.5%) and H. somni (22.9%). Compared to those with BRD, healthy cattle were less likely to be positive for P. multocida (OR = 0.27), M. haemolytica (OR = 0.32), or H. somni (OR = 0.25). There were high levels of resistance (>70%) against tulathromycin and oxytetracycline in M. haemolytica and P. multocida isolates and high levels of resistance against oxytetracycline (67%) and penicillin (52%) in H. somni isolates. None or few isolates were resistant to florfenicol, enrofloxacin and ceftiofur. The high prevalence of resistance against tulathromycin and oxytetracycline suggests that these antimicrobials should not be repeatedly used for both control and treatment of BRD and/or histophilosis. [ABSTRACT FROM AUTHOR]

Problem addressed Shiga toxin-producing Escherichia coli (STEC) are a group of bacteria responsible for food-associated diseases. Clinical features include a wide range of symptoms such as diarrhea, hemorrhagic colitis and the hemolytic uremic syndrome (HUS), a life-threatening condition. Objective Our group has observed that animals naturally colonized with STEC strains of unknown serotype were not efficiently colonized with E. coli O157:H7 after experimental infection. In order to assess the basis of the interference, three STEC strains were isolated from STEC persistently-colonized healthy cattle from a dairy farm in Buenos Aires, Argentina. Methods and results The three isolated strains are E. coli O22:H8 and carry the stx1 and stx2d genes. The activatable activity of Stx2d was demonstrated in vitro . The three strains carry the adhesins iha , ehaA and lpf O113 . E. coli O22:H8 formed stronger biofilms in abiotic surface than E. coli O157:H7 ( eae+, stx2+ ) and displayed a more adherent phenotype in vitro towards HeLa cells. Furthermore, when both serotypes were cultured together O22:H8 could reduce O157:H7 adherence in vitro . When calves were intragastrically pre-challenged with 10 8 CFU of a mixture of the three STEC strains and two days later challenged with the same dose of the strain E. coli O157:H7 438/99, the shedding of the pathogen was significantly reduced. Conclusions These results suggest that E. coli O22:H8, a serotype rarely associated with human illness, might compete with O157:H7 at the bovine recto-anal junction, making non-O157 carrying-calves less susceptible to O157:H7 colonization and shedding of the bacteria to the environment. [ABSTRACT FROM AUTHOR]

Bovine respiratory disease (BRD) is one of the most serious causes of health and economic problems in the beef production industry, especially in recently weaned, intensely raised and newly transported feedlot cattle. While the importance of upper airway structure and function in the susceptibility of the lower respiratory tract to colonization with potential pathogens is well established, the role of the mucosal microbiota in respirtatory health is less well defined. The objective of this study was to characterize the nasopharyngeal microbiota of feedlot cattle at entry into a commercial feedlot, during initial management processing, and to compare the dynamics of change in these microbial communities between clinically healthy calves and those that develop BRD within the first month after entry. Deep nasopharyngeal swabs were collected from randomly selected healthy calves (n = 66) during initial handling and processing at the feedlot, and again at the initial diagnosis of BRD (n = 22). Clinically healthy pen matched controls calves (n = 10) were sampled at the same time as the BRD affected animals. Genomic DNA was extracted from each sample, and the 16S rRNA gene V1-V3 hypervariable region was amplified and sequenced using the Illumina MiSeq platform. Across all the samples, the predominant bacterial phyla were Proteobacteria , Firmicutes and Actinobacteria. While the predominant genera were Moraxella , Mycoplasma and Acinetobacter . Linear discriminant analysis (LDA) effect size (LEfSe) revealed significant differences in bacterial taxa between healthy and BRD affected calves. Discriminant analysis revealed that the nasopharyngeal microbiota in feedlot calves at entry and in BRD affected calves were distinct from pen matched healthy calves. While the temporal dynamics of this shift were not examined in this study, it is possible that the observed changes in mucosal microbiota are linked to the increased susceptibility of calves to BRD during the first month after entry in to the feedlot. Additional studies are needed to examine the trajectory of change in nasopharyngeal microbial communities from entry to disease onset, and to explore the impact of other factors such as diet transition, commingling, vaccination and housing on the nasopharyngeal microbiota of growing cattle. [ABSTRACT FROM AUTHOR]

Vaccination of cattle against bovine tuberculosis could be a valuable control strategy, particularly in countries faced with intractable ongoing infection from a disease reservoir in wildlife. A field vaccination trial was undertaken in New Zealand. The trial included 1286 effectively free-ranging cattle stocked at low densities in a remote 7600 ha area, with 55% of them vaccinated using Mycobacterium bovis BCG (Danish strain 1311). Vaccine was administered orally in all but 34 cases (where it was injected). After inclusion, cattle were exposed to natural sources of M. bovis infection in cattle and wildlife, most notably the brushtail possum ( Trichosurus vulpecula ). Cattle were slaughtered at 3–5 years of age and were inspected for tuberculous lesions, with mycobacteriological culture of key tissues from almost all animals. The prevalence of M. bovis infection was 4.8% among oral BCG vaccinates, significantly lower than the 11.9% in non-vaccinates. Vaccination appeared to both reduce the incidence of detectable infection, and to slow disease progression. Based on apparent annual incidence, the protective efficacy of oral BCG vaccine was 67.4% for preventing infection, and was higher in cattle slaughtered soon after vaccination. Skin-test reactivity to tuberculin was high in vaccinates re-tested 70 days after vaccination but not in non-vaccinates, although reactor animals had minimal response in gamma-interferon blood tests. In re- tests conducted more than 12 months after vaccination, skin-test reactivity among vaccinates was much lower. These results indicate that oral BCG vaccination could be an effective tool for greatly reducing detectable infection in cattle. [ABSTRACT FROM AUTHOR]

The species composition and distribution of ciliates were investigated in the rumen contents of 15 domestic cattle (Bos taurus taurus L.) living in the European part of İstanbul, Turkey. Thirty-five species and 13 morphotypes belonging to 13 genera were identified. The density of rumen ciliates in cattle was 31.8 (± 21.3) × 104 cells ml-1, and the mean number of ciliate species per host was 12.9 ± 4.4. Of the ciliate species, Dasytricha ruminantium, Entodinium simulans, and Isotricha prostoma were the most abundant, each with a prevalence of 93.3%, whereas Diplodinium anisacanthum, D. dogieli, D. rangiferi, Enoploplastron triloricatum, Metadinium medium, and Ostraco' dinium munham were detected only in one animal (6.7% prevalence). Eodinium posterovesiculatum m. bilobosum and D. dogieli are new host records for cattle in Turkey. The infraciliature of M. medium (Entodiniomorphida, Ophryoscolecidae) was examined and detected for the first time. The buccal infraciliature of M. medium was composed of three polybrachykineties, a kinety loop, and paralabial kineties. A large dorso-adoral polybrachykinety, a gentle S-shaped curved vestibular polybrachykinety, and a kinety loop between the dorso-adoral polybrachykinety and adoral polybrachykinety were characteristics. Because of these features, M. medium-type buccal infraciliature was between the Ostracodinium gracile-type buccal infraciliature and the Ostracodinium mammosum-type buccal infraciliature. [ABSTRACT FROM AUTHOR]

Microbiological data on hygiene indicators are important fo r assessment o f hygiene levels in abattoirs and control o f carcass contamination. Risk categorization o f slaughterhouses should be based on a process hygiene output through the use o f indicator organisms - Total Viable Counts (TVC), Enterobacteriaceae counts (EC) and Salmonella spp. - monitored on carcasses. The level o f TVC indicates the overall hygiene in abattoirs (equipment, tools, workers), while the presence o f EC on carcasses can indicate fecal contamination which can occur during slaughter/dressing. Detection o f Salmonella spp. indicates the presence o f pathogens, with potential origin from the farm. The aim o f this study was to assess the slaughter process hygiene in abattoirs o f different sizes and throughputs, a large- and a small-scale abattoir, and to analyze differences in process hygiene levels based on implementation o f their self-control plans, throughout a period offive years for cattle and six years fo r pigs. In the large-scale abattoir, TVC levels were slightly higher on cattle carcasses than on pig carcasses, but were always within the regulatory satisfactory or acceptable ranges. In the small-scale abattoir, low counts o f EC were observed on cattle and pig carcasses, with slightly higher levels on cattle carcasses, but the counts were always within the regulatory satisfactory range. Higher TVC levels on both cattle and pig carcasses were observed in the large-scale abattoir versus the small-scale abattoir, but both abattoirs still showed process hygiene levels within the regulatory satisfactory or acceptable range. Salmonella was recovered only from two pig carcasses in the large-scale abattoir. The study revealed that TVC levels differed more on pig carcasses, while EC levels differed more on cattle carcasses. Process hygiene levels in both abattoirs were always in the allowed regulatory range and also were similar to the hygiene levels in other, developed European countries. [ABSTRACT FROM AUTHOR]

Resistance to third-generation cephalosporins and other beta-lactam antibiotics is of major concern for animal and human health. Knowledge of the prevalence of resistant bacteria in primary production is an important element to estimate transmission along the stages in the food production chain and the exposure of the human population. The primary objective of this study was to determine the prevalence of cefotaxime-resistant commensal E. coli in dairy and beef cattle production units throughout Germany. Secondarily, the association between management factors and the presence of cefotaxime resistance was investigated. In total, 60 beef cattle and 52 dairy cattle production units all over Germany were included. Cefotaxime-resistant E. coli were isolated from at least one sample in 70% (95% CI: 58–83%) of the farms keeping beef cattle and 85% (95% CI: 75–94%) of the farms keeping dairy cattle. The sample prevalence was 35% (161/455; 95% CI: 31–40%) and 48% (156/323; 95% CI: 43–54%), respectively. Most factors associated with resistance to cefotaxime indicate that less intensive production results in a lower number of positive samples. For beef cattle, antimicrobial treatment of the whole animal group was significantly associated with an increased proportion of samples containing cefotaxime resistant E. coli . In addition, our results indicate that better hygiene management could improve the resistance situation on cattle farms. [ABSTRACT FROM AUTHOR]

Background: Campylobacter (C.) jejuni is the leading cause of human campylobacteriosis worldwide. We performed a molecular epidemiological study to investigate the genetic relationship among C. jejuni strains isolated from human diarrhoeal patients, broiler products and dairy cattle in Lithuania.Methods: The C. jejuni isolates from human clinical cases, dairy cattle and broiler products were genotyped using multilocus sequence typing (MLST). Allele numbers for each housekeeping gene, sequence type (ST), and clonal complex (CC) were assigned by submitting the DNA sequences to the C. jejuni MLST database ( http://pubmlst.org/campylobacter ). Based on the obtained sequence data of the housekeeping genes a phylogenetic analysis of the strains was performed and a minimum spanning tree (MST) was calculated.Results: Among the 262 C. jejuni strains (consisting of 43 strains isolated from dairy cattle, 102 strains isolated from broiler products and 117 clinical human C. jejuni strains), 82 different MLST sequence types and 22 clonal complexes were identified. Clonal complexes CC21 and CC353 predominated among the C. jejuni strains. On ST-level, five sequence types (ST-5, ST-21, ST-50, ST-464 and ST-6410) were dominating and these five STs accounted for 35.9% (n = 94) of our isolates. In addition, 51 (19.5%) C. jejuni strains representing 27 (32.9%) STs were reported for the first time in the PubMLST database ( http://pubmlst.org/campylobacter ). The highest Czekanowski index or proportional similarity index (PSI) was calculated for C. jejuni strains isolated from human campylobacteriosis cases and broiler products (PSI = 0.32) suggesting a strong link between broiler strains and human cases. The PSI of dairy cattle and human samples was lower (PSI = 0.11), suggesting a weaker link between bovine strains and human cases. The calculated Simpson's index of all C. jejuni isolates showed a high genetic diversity (D = 0.96).Conclusion: Our results suggest that broiler products are the most important source of human campylobacteriosis in Lithuania. The study provides information on MLST type distribution and genetic relatedness of C. jejuni strains from humans, broiler products and dairy cattle in Lithuania for the first time, enabling a better understanding of the transmission pathways of C. jejuni in this country. [ABSTRACT FROM AUTHOR]

Objectives: To identify and characterize a novel cfr variant that recently emerged and confers multidrug resistance in Campylobacter , a major foodborne pathogen.Methods: WGS was initially used to identify the cfr (C) gene in Campylobacter isolates and its function was further verified by cloning into an antibiotic-susceptible Campylobacter jejuni strain. Distribution of cfr (C) in various Campylobacter isolates was determined by PCR analysis. Genotyping of cfr (C)-positive strains was done by PFGE and MLST.Results: The cfr (C) gene is predicted to encode a protein that shares 55.1% and 54.9% identity with Cfr and Cfr(B), respectively. cfr (C) was located on a conjugative plasmid of ∼48 kb. Cloning of cfr (C) into C. jejuni NCTC 11168 and conjugative transfer of the cfr (C)-containing plasmid confirmed its role in conferring resistance to phenicols, lincosamides, pleuromutilins and oxazolidinones, and resulted in an 8-256-fold increase in their MICs in both C. jejuni and Campylobacter coli . The cfr (C) gene was detected in multiple C. coli (34 of 344; 10%) isolates derived from different cattle farms in different states, and molecular typing of the cfr (C)-positive C. coli isolates revealed its spread mainly via clonal expansion.Conclusions: These results identify cfr (C) as a new multidrug resistance mechanism in Campylobacter and suggest the potential transmission of this mechanism via the foodborne route, warranting enhanced efforts to monitor its spread in Campylobacter and other foodborne pathogens. [ABSTRACT FROM AUTHOR]

Antimicrobial agents are used in cattle production systems for the prevention and control of bacterial associated diseases. A consequence of their use is the potential development of antimicrobial resistance (AMR). Enterococcus faecium and Enterococcus faecalis that are resistant to antimicrobials are of increased concern to public health officials throughout the world as they may compromise the ability of various treatment regimens to control disease and infection in human medicine. Australia is a major exporter of beef; however it does not have an ongoing surveillance system for AMR in cattle or foods derived from these animals. This study examined 910 beef cattle, 290 dairy cattle and 300 veal calf faecal samples collected at slaughter for the presence of enterococci. Enterococcus were isolated from 805 (88.5%) beef cattle faeces, 244 (84.1%) dairy cattle faeces and 247 (82.3%) veal calf faeces with a total of 800 enterococci subsequently selected for AMR testing. The results of AMR testing identified high levels of resistance to antimicrobials that are not critically or highly important to human medicine with resistance to flavomycin (80.2%) and lincomycin (85.4–94.2%) routinely observed. Conversely, resistance to antibiotics considered critically or highly important to human medicine such as tigecycline, daptomycin, vancomycin and linezolid was not present in this study. There is minimal evidence that Australian cattle production practices are responsible for disproportionate contributions to AMR development and in general resistance to antimicrobials of critical and high importance in human medicine was low regardless of the isolate source. The low level of antimicrobial resistance in Enterococcus from Australian cattle is likely to result from comprehensive controls around the use of antimicrobials in food-production animals in Australia. Nevertheless, continued monitoring of the effects of all antimicrobial use is required to support Australia’s reputation as a supplier of safe and healthy food. [ABSTRACT FROM AUTHOR]

Background: There is paucity of information regarding the epidemiology of Escherichia coli O157: H7 in developing countries. In this study, we investigated the occurrence of E. coli O157: H7 associated with beef cattle at processing plants and at retail shops in Ethiopia.Methods: Various samples were collected from beef cattle at slaughter/processing plants, carcass at retail shops and humans at health centers. E. coli O157: H7 was isolated, identified and characterized for antimicrobial resistance, using standard microbiological methods.Results: At the processing plants E. coli O157: H7 was detected in 1.89% of fecal, 0.81% of intestinal mucosal swab, 0.54% of skin swab and 0.54% of carcass internal swab samples. At retail shops it was detected in 0.8% of carcass and 0.8% of cutting board swab samples, while all samples from utensils, hands from workers, and fecal and stool samples were negative. All isolates were resistant to Amoxicillin, moderately resistant to Cefoxitine and Nitrofurantoins but susceptible to other antimicrobials tested.Conclusions: E. coli O157: H7 occurs at low prevalence in beef cattle, and the current sanitary dressing procedures in the processing plants and storage conditions in the retail shops are effective against E. coli O157: H7. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the influence of the slaughter technique (Halal vs Classical slaughter) on the superficial contamination of cattle carcasses, by using traditional microbiological procedures and 16S rDNA metagenetics. The purpose was also to investigate the neck area to identify bacteria originating from the digestive or the respiratory tract. Twenty bovine carcasses (10 from each group) were swabbed at the slaughterhouse, where both slaughtering methods are practiced. Two swabbing areas were chosen: one “legal” zone of 1600 cm 2 (composed of zones from rump, flank, brisket and forelimb) and locally on the neck area (200 cm 2 ). Samples were submitted to classical microbiology for aerobic Total Viable Counts (TVC) at 30 °C and Enterobacteriaceae counts, while metagenetic analysis was performed on the same samples. The classical microbiological results revealed no significant differences between both slaughtering practices; with values between 3.95 and 4.87 log CFU/100 cm 2 and 0.49 and 1.94 log CFU/100 cm 2 , for TVC and Enterobacteriaceae respectively. Analysis of pyrosequencing data showed that differences in the bacterial population abundance between slaughtering methods were mainly observed in the “legal” swabbing zone compared to the neck area. Bacterial genera belonging to the Actinobacteria phylum were more abundant in the “legal” swabbing zone in “Halal” samples, while Brevibacterium and Corynebacterium were encountered more in “Halal” samples, in all swabbing areas. This was also the case for Firmicutes bacterial populations (families of Aerococcaceae , Planococcaceae ). Except for Planococcoceae , the analysis of Operational Taxonomic Unit (OTU) abundances of bacteria from the digestive or respiratory tract revealed no differences between groups. In conclusion, the slaughtering method does not influence the superficial microbiological pattern in terms of specific microbiological markers of the digestive or respiratory tract. However, precise analysis of taxonomy at the genus level taxonomy highlights differences between swabbing areas. Although not clearly proven in this study, differences in hygiene practices used during both slaughtering protocols could explain the differences in contamination between carcasses from both slaughtering groups. [ABSTRACT FROM AUTHOR]

We investigated the microbiota found in the vaginas of Holstein dairy cows during the transition period and described the differences in bacterial composition and total bacterial load (TBL) associated with disease and fertility. Vaginal swabs were collected at -7, 0, 3, and 7 d relative to parturition from 111 dairy cows housed on a commercial dairy farm near Ithaca, New York. Microbiota were characterized by next-generation DNA sequencing of the bacterial 16S rRNA gene, and TBL was determined by real-time quantitative PCR. We applied repeated-measures ANOVA to evaluate the associations of uterine disease and related risk factors with the microbiota and TBL. We estimated phylum-specific bacterial load by multiplying the TBL by the relative abundance of each phylum observed in the metagenomics results. We confirmed the validity of this approach for estimating bacterial load by enumerating the number of bacteria in an artificial sample mixed in vitro and in clinical and healthy vaginal samples. Phyla associated with uterine disease and related risk factors were Proteobacteria, Fusobacteria, and Bacteroidetes. Cows with retained placenta and healthy cows had similar TBL at the day of parturition, but at d 7 postpartum, cows with retained placenta showed a significantly higher TBL, mainly driven by higher estimated loads of Fusobacteria and Bacteroidetes. Cows diagnosed with metritis had a significantly higher estimated load of Proteobacteria at d -7 and at calving and higher estimated loads of Fusobacteria in the postpartum samples. Additionally, the estimated load of Bacteroidetes at d 7 postpartum was higher for cows diagnosed with endometritis at 35 days in milk. Higher estimated loads of Fusobacteria and Bacteroidetes were also evident in cows with postpartum fever, in primiparous cows, in cows with assisted parturition, and in cows that gave birth to twins. Our findings demonstrated that microbiota composition and TBL were associated with known periparturient risk factors of uterine diseases and reproductive failure, including parity, assisted parturition, and retained fetal membranes. [ABSTRACT FROM AUTHOR]

Contents This study was conducted to determine the effect of immunization with inhibin DNA vaccine delivered by attenuated Salmonella choleraesuis on ovarian responses and fertility in cross-bred buffaloes. A total of 134 cross-bred buffaloes were divided into four groups: groups T1 ( n = 34), T2 ( n = 35) and T3 ( n = 31) were nasal immunized twice a day with 10 ml of 1 × 1010 CFU/ml of the C501 (pVAX-asd-IS) vaccine for 5, 3 and 1 day, respectively. Group C ( n = 34) was nasal immunized with 10 ml PBS for 5 days. All animals were immunized twice with an interval of 14 days and administered with 200 μg of a GnRH analogue on day 28, 0.5 mg PGF2α on day 35 and 200 μg of the same GnRH analogue on day 37. TAI was performed at 18 and 24 hr after the second GnRH treatment. Fourteen days after primary immunization, C501 (pVAX-asd-IS) elicited significant immune responses, and anti-inhibin IgG antibody titres in group T1 were significantly higher ( p < .01) than groups T3 and C. After the second GnRH treatment, the growth speed of the dominant follicles in group T1 was significantly faster ( p < .05) than groups T3 and C. The number and diameter of large follicles (≥10 mm) as well as ovulatory follicles in group T1 were the greatest in all groups, resulting in a greater conception rate in buffaloes with positive anti-inhibin antibodies. These results demonstrate that immunization with the C501 (pVAX-asd-IS) vaccine, coupled with the Ovsynch protocol, could be used as an alternative approach to improve reproductive performance in cross-bred buffaloes. [ABSTRACT FROM AUTHOR]

Bactrian camels may have a unique gastrointestinal (GI) microbiome because of their distinctive digestive systems, unique eating habits and extreme living conditions. However, understanding of the microbial communities in the Bactrian camel GI tract is still limited. In this study, microbial communities were investigated by comparative analyses of 16S rRNA hypervariable region V4 sequences of fecal bacteria sampled from 94 animals in four population groups: Inner Mongolian cattle (IMG-Cattle), Inner Mongolian domestic Bactrian camels (IMG-DBC), Mongolian domestic Bactrian camels (MG-DBC), and Mongolian wild Bactrian camels (MG-WBC). A total of 2,097,985 high-quality reads were obtained and yielded 471,767,607 bases of sequence. Firmicutes was the predominant phylum in the population groups IMG-Cattle, IMG-DBC and MG-WBC, followed (except in the Inner Mongolian cattle) by Verrucomicrobia. Bacteroidetes were abundant in the IMG-DBC and MG-WBC populations. Hierarchical clustered heatmap analysis revealed that the microbial community composition within the three Bactrian camel groups was relatively similar, and somewhat distinct from that in the cattle. A similar result was determined by principal component analysis, in which the camels grouped together. We also found several species-specific differences in microbial communities at the genus level: for example, Desulfovibrio was abundant in the IMG-DBC and MG-WBC groups; Pseudomonas was abundant in the IMG-Cattle group; and Fibrobacter, Coprobacillus, and Paludibacter were scarce in the MG-WBC group. Such differences may be related to different eating habits and living conditions of the cattle and the various camel populations. [ABSTRACT FROM AUTHOR]

The objective of this study was to characterize blaOXA-23 harbouring Acinetobacter indicus-like strains from cattle including genomic and phylogenetic analyses, antimicrobial susceptibility testing and evaluation of pathogenicity in vitro and in vivo. Nasal and rectal swabs (n = 45) from cattle in Germany were screened for carbapenem-non-susceptible Acinetobacter spp. Thereby, two carbapenem resistant Acinetobacter spp. from the nasal cavities of two calves could be isolated. MALDI-TOF mass spectrometry and 16S rDNA sequencing identified these isolates as A. indicus-like. A phylogenetic tree based on partial rpoB sequences indicated closest relation of the two bovine isolates to the A. indicus type strain A648T and human clinical A. indicus isolates, while whole genome comparison revealed considerable intraspecies diversity. High mimimum inhibitory concentrations were observed for carbapenems and other antibiotics including fluoroquinolones and gentamicin. Whole genome sequencing and PCR mapping revealed that both isolates harboured blaOXA-23 localized on the chromosome and surrounded by interrupted Tn2008 transposon structures. Since the pathogenic potential of A. indicus is unknown, pathogenicity was assessed employing the Galleria (G.) mellonella infection model and an in vitro cytotoxicity assay using A549 human lung epithelial cells. Pathogenicity in vivo (G. mellonella killing assay) and in vitro (cytotoxicity assay) of the two A. indicus-like isolates was lower compared to A. baumannii ATCC 17978 and similar to A. lwoffii ATCC 15309. The reduced pathogenicity of A. indicus compared to A. baumannii correlated with the absence of important virulence genes encoding like phospholipase C1+C2, acinetobactin outer membrane protein BauA, RND-type efflux system proteins AdeRS and AdeAB or the trimeric autotransporter adhesin Ata. The emergence of carbapenem-resistant A. indicus-like strains from cattle carrying blaOXA-23 on transposable elements and revealing genetic relatedness to isolates from human clinical sources requires further investigations regarding the pathogenic potential, genomic characteristics, zoonotic risk and putative additional sources of this new Acinetobacter species. [ABSTRACT FROM AUTHOR]

Escherichia coli O157:H7 is a foodborne pathogen that colonizes ruminants. Cattle are considered the primary reservoir of E. coli O157:H7 with super-shedders, defined as individuals excreting > 104 E. coli O157:H7 CFU g-1 feces. The mechanisms leading to the super-shedding condition are largely unknown. Here, we used 16S rRNA gene pyrosequencing to examine the composition of the fecal bacterial community in order to investigate changes in the bacterial microbiota at several locations along the digestive tract (from the duodenum to the rectal-anal junction) in 5 steers previously identified as super-shedders and 5 non-shedders. The overall bacterial community structure did not differ by E. coli O157:H7 shedding status; but several differences in the relative abundance of taxa and OTUs were noted between the two groups. The genus Prevotella was most enriched in the non-shedders while the genus Ruminococcus and the Bacteroidetes phylum were notably enriched in the super-shedders. There was greater bacterial diversity and richness in samples collected from the lower- as compared to the upper gastrointestinal tract (GI). The spiral colon was the only GI location that differed in terms of bacterial diversity between super-shedders and non-shedders. These findings reinforced linkages between E. coli O157:H7 colonization in cattle and the nature of the microbial community inhabiting the digestive tract of super-shedders. [ABSTRACT FROM AUTHOR]

Verotoxin-producing E. coli (VTEC) O157:H7 is the dominant serotype isolated from patients with HUS and, Argentina has the highest rate of HUS in the world. Molecular typing had allowed to identify subpopulations related to the origin and virulence of O157:H7 strains. Our aim was to perform a genetic characterization of 43 O157:H7 strains isolated in Argentine mostly from cattle and humans in order to establish the potential public health risk. For it, we used a combination of molecular subtyping methods in order to identify clade 8_ rhsA ( C3468G ), LSPA-6 and virulence profiles and, a cytotoxicity assay on Vero cell. All isolates carried the clade 8 SNP variant and 98% of them belonged to lineage I/II (2% lineage II). Isolates were grouped into eleven nle profiles, 46% were positive for all nle genes, while the remaining isolates, except two, showed incomplete OI-71, particularly lacked nleF . All isolates showed the plasmid profile ehxA-espP-katP-stcE and harbored ehaA , elfA , iha and l pfA variants lpfA1-3 and lpfA2-2 and, ECSP_0242. The frequencies of the remaining ECSP genes were 95% ECSP_2687, 88% ECSP_3286, 86% ECSP_3620, 53% ECSP_2870/2872 and 44% ECSP_1733. All O157:H7 strains, except the isolate identified as lineage II, were cytotoxic on Vero cells. Among Argentinean strains, most genetic markers occur at equal relative frequencies among clinical and bovine isolates, showing diversity mostly in nle genes profiles. The belonging of the isolates to hypervirulent clade 8 and lineage I/II, the high prevalence of nle and putative virulence factors genes, would allow assigning most O157:H7 strains of this region a high risk to public health. [ABSTRACT FROM AUTHOR]

Objectives: To investigate the epidemiological characteristics and the surrounding genetic structure of the blaNDM-5 gene in Klebsiella pneumoniae derived from dairy cows in Jiangsu Province, China.Methods: Ten carbapenem-resistant K. pneumoniae were collected from three dairy farms and were screened for the presence of carbapenemase genes using PCR and sequencing. PFGE and MLST were conducted to analyse the genetic relatedness of the blaNDM-5-harbouring K. pneumoniae isolates. The location of blaNDM-5 was identified by S1 nuclease-PFGE and Southern blotting. The transferability and profiles of blaNDM-5-carrying plasmids were analysed by conjugation experiments, and PCR-based replicon typing and RFLP, respectively. The surrounding genetic structure of the blaNDM-5 gene was obtained using WGS and PCR mapping.Results: All 10 K. pneumoniae from dairy cows harboured the blaNDM-5 gene, exhibited resistance to multiple antimicrobials and belonged to five STs, of which ST1661 and ST2108 were the most prevalent. The blaNDM-5 gene was located on the ∼46 kb IncX3 plasmid in all isolates and these plasmids could be conjugated to an Escherichia coli recipient with no additional resistance profiles transferred. All blaNDM-5-carrying plasmids shared similar genetic contexts and were nearly identical to that of the human K. pneumoniae plasmid (pNDM-MGR194) previously reported in India.Conclusions: This was the first case of blaNDM-5-positive K. pneumoniae identified from dairy cows in China. The IncX3 pNDM-MGR194-like plasmid disseminated among cow farms should be highlighted and its potential role in mediating transmission of the blaNDM gene between bacteria from humans and animals requires further monitoring. [ABSTRACT FROM AUTHOR]

Four protease preparations from plant and fungal sources (papain, bromelain, FP400 and FPII) were used to hydrolyse plasma which was separated from slaughterhouse cattle blood. The o -phthaldialdehyde assay was used to follow the release of TCA-soluble peptides over a 24 h period. Hydrolysis profiles were displayed using SDS-PAGE. The in vitro antioxidant and antimicrobial activities of the hydrolysates were determined. The results showed that hydrolysates of cattle plasma generated with fungal protease FPII had higher antioxidant activities. Overall than hydrolysates generated with papain, bromelain and FP400. None of the hydrolysates demonstrated antimicrobial activity. The FPII peptide hydrolysate was fractionated using gel permeation chromatography, OFFGEL isoelectric focusing and RP-HPLC. The RP-HPLC fraction with highest antioxidant activity contained 15 novel peptide sequences. The use of protease FPII to hydrolyse cattle plasma resulted in a hydrolysate with high antioxidant properties and unique peptide sequences. [ABSTRACT FROM AUTHOR]

Poly(3-hydroxybutyrate)-producingEnterococcus faeciumKT722772 was isolated from cattle rumen fluid by Sudan black staining. It was found to be gram-positive cocci. Poly(3-hydroxybutyrate) production usingE. faeciumKT722772 was optimized at different pH ranging from 2 to 7 and with different substrates such as glucose, butyric acid, propionic acid, sodium acetate, and glycerol as a sole carbon source at a concentration ranging from 0 to 4%. Maximum poly 3-hydroxy butyrate production (1.8 g/L) was achieved with 1% butyric acid at pH 7. Poly 3-hydroxy butyrate produced byE. faeciumwas characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, and X-ray diffraction analysis. [ABSTRACT FROM AUTHOR]

Shiga toxin-producing Escherichia coli (STEC) O157:H7 is an important foodborne pathogen worldwide. In Turkey, little is known about the molecular characteristics of STEC O157:H7 isolates. The aim of this study was to examine the genetic diversity of STEC O157:H7 isolates from cattle in Turkey using pulsed-field gel electrophoresis (PFGE). A total of 18 STEC O157:H7 strains were isolated from 540 rectal swab samples of slaughtered cattle in two abattoirs (coded A and B) located in eastern Turkey. The presence of virulence genes (stx1, stx2, hlyA and eae) was detected using the polymerase chain reaction. Of the 18 STEC O157:H7 isolates, 14 had stx2, hlyA, and eae genes. Four of the isolates were positive for stx1, stx2, hlyA, and eae genes. Thirteen different PFGE patterns were observed among the STEC O157:H7 isolates. The most common PFGE pattern was X1, which was detected in six STEC O157:H7 isolates. These six isolates contained the same virulence genes (stx2, eae and hlyA). However, some of the isolates containing the same virulence genes showed different PFGE profiles. Eleven different PFGE patterns were detected among the isolates from abattoir B, and two different PFGE patterns were detected among the isolates from abattoir A. The results of PFGE revealed a wide genetic diversity among the STEC O157:H7 isolates from cattle in Turkey. This is the first study on PFGE typing of STEC O157:H7 isolates from cattle in Turkey and further studies are needed. [ABSTRACT FROM AUTHOR]

Streptococcus agalactiae is an emerging pathogen of nonpregnant human adults worldwide and a reemerging pathogen of dairy cattle in parts of Europe. To learn more about interspecies transmission of this bacterium, we compared contemporaneously collected isolates from humans and cattle in Finland and Sweden. Multilocus sequence typing identified 5 sequence types (STs) (ST1, 8, 12, 23, and 196) shared across the 2 host species, suggesting possible interspecies transmission. More than 54% of the isolates belonged to those STs. Molecular serotyping and pilus island typing of those isolates did not differentiate between populations isolated from different host species. Isolates from humans and cattle differed in lactose fermentation, which is encoded on the accessory genome and represents an adaptation to the bovine mammary gland. Serotype IV-ST196 isolates were obtained from multiple dairy herds in both countries. Cattle may constitute a previously unknown reservoir of this strain. [ABSTRACT FROM AUTHOR]

Many factors can affect animal feed efficiency which is one of the important economic traits in the beef industry. To date, our understanding of the role of the rumen microbiota and its impact on feed efficiency is largely unknown. The objective of this paper was to determine if the rumen microbiota is associated with residual feed intake (RFI) by studying the metatranscriptome of the rumen microbiome from cattle with different RFI values. The microbial transcriptome profiles revealed that Succinivibrionaceae and Methanomassiliicoccales were the most active microbial phylotypes, occupying approximately 44.1% and 35.6% of the bacterial and archaeal communities in the rumen of steers fed with barley-based diet, respectively. Further, the relative abundance of Lachnospiraceae, Veillonellaceae, and p-2534–18B5 bacterial families and Methanomassiliicoccales archaeal taxa were different between low RFI (L-RFI; efficient) and high RFI (H-RFI; inefficient) beef steers. The microbiome of L-RFI animals possessed characteristics associated with higher metabolic function and cell survivability, suggesting that enhanced fermentation capacity and adaptability of the microbiome may be key factors to improve nutrient availability. Our results provide evidence that the rumen microbiome could be one of the biological factors associated with variation in cattle feed efficiency. [ABSTRACT FROM AUTHOR]