Longitudinal Changes in Campylobacter and the Litter Microbiome throughout the Broiler Production Cycle.

Broiler chickens are an important source of Campylobacter to humans and become colonized on the farm, but the role of the litter in the ecology of Campylobacter is still not clear. The aim of this study was to examine the relationship between Campylobacter and the changes in the litter microbiome throughout the broiler production cycle. Twenty-six commercial broiler flocks representing two production types (small and big broilers) were followed from 1 to 2 weeks after placement to the end of the production cycle. Composite litter samples from the broiler chicken house were collected weekly. Litter DNA was extracted and used for Campylobacter jejuni and Campylobacter coli qPCR as well as for 16S rRNA gene V4 region sequencing. Campylobacter jejuni concentration in litter significantly differed by production type and flock age. Campylobacter jejuni concentration in litter from big broilers was 2.4 log10 units higher, on average, than that of small broilers at 3 weeks of age. Sixteen amplicon sequence variants (ASVs) differentially abundant over time were detected in both production types. A negative correlation of Campylobacter with Bogoriella and Pseudogracilibacillus was observed in the litter microbiome network at 6 weeks of flock age. Dynamic Bayesian networks provided evidence of negative associations between Campylobacter and two bacterial genera, Ornithinibacillus and Oceanobacillus, at 2 and 4 weeks of flock age, respectively. In conclusion, dynamic associations between Campylobacter and the litter microbiome were observed during grow-out, suggesting a potential role of the litter microbiome in the ecology of Campylobacter colonization and persistence on farm. IMPORTANCE This study interrogated the longitudinal association between Campylobacter and broiler litter microbiome in commercial broiler flocks. The results of this investigation highlighted differences in Campylobacter dynamics in the litter throughout the broiler production cycle and between small and big broilers. Besides documenting the changing nature of the microbial networks in broiler litter during grow-out, we detected bacterial genera (Oceanobacillus and Ornithinibacillus) negatively associated with Campylobacter abundance and concentration in litter via the Bayesian network framework. These bacteria should be investigated as possible antagonists to Campylobacter colonization of the broiler environment.

Comprehensive time-course gene expression evaluation of high-risk beef cattle to establish immunological characteristics associated with undifferentiated bovine respiratory disease.

Bovine respiratory disease (BRD) remains the leading infectious disease in beef cattle production systems. Host gene expression upon facility arrival may indicate risk of BRD development and severity. However, a time-course approach would better define how BRD development influences immunological and inflammatory responses after disease occurrences. Here, we evaluated whole blood transcriptomes of high-risk beef cattle at three time points to elucidate BRD-associated host response. Sequenced jugular whole blood mRNA from 36 cattle (2015: n = 9; 2017: n = 27) across three time points (n = 100 samples; days [D]0, D28, and D63) were processed through ARS-UCD1.2 reference-guided assembly (HISAT2/Stringtie2). Samples were categorized into BRD-severity cohorts (Healthy, n = 14; Treated 1, n = 11; Treated 2+, n = 11) via frequency of antimicrobial clinical treatment. Assessment of gene expression patterns over time within each BRD cohort was modeled through an autoregressive hidden Markov model (EBSeq-HMM; posterior probability ≥ 0.5, FDR < 0.01). Mixed-effects negative binomial models (glmmSeq; FDR < 0.05) and edgeR (FDR < 0.10) identified differentially expressed genes between and across cohorts overtime. A total of 2,580, 2,216, and 2,381 genes were dynamically expressed across time in Healthy, Treated 1, and Treated 2+ cattle, respectively. Genes involved in the production of specialized resolving mediators (SPMs) decreased at D28 and then increased by D63 across all three cohorts. Accordingly, SPM production and alternative complement were differentially expressed between Healthy and Treated 2+ at D0, but not statistically different between the three groups by D63. Magnitude, but not directionality, of gene expression related to SPM production, alternative complement, and innate immune response signified Healthy and Treated 2+ cattle. Differences in gene expression at D63 across the three groups were related to oxygen binding and carrier activity, natural killer cell-mediated cytotoxicity, cathelicidin production, and neutrophil degranulation, possibly indicating prolonged airway pathology and inflammation weeks after clinical treatment for BRD. These findings indicate genomic mechanisms indicative of BRD development and severity over time.

Genomic Profiling of Antimicrobial Resistance Genes in Clinical Salmonella Isolates from Cattle in the Texas Panhandle, USA.

Rising antimicrobial resistance (AMR) in Salmonella serotypes host-adapted to cattle is of increasing concern to the beef and dairy industry. The bulk of the existing literature focuses on AMR post-slaughter. In comparison, the understanding of AMR in Salmonella among pre-harvest cattle is still limited, particularly in Texas, which ranks top five in beef and dairy exports in the United States; inherently, the health of Texas cattle has nationwide implications for the health of the United States beef and dairy industry. In this study, long-read whole genome sequencing and bioinformatic methods were utilized to analyze antimicrobial resistance genes (ARGs) in 98 isolates from beef and dairy cattle in the Texas Panhandle. Fisher exact tests and elastic net models accounting for population structure were used to infer associations between genomic ARG profiles and antimicrobial phenotypic profiles and metadata. Gene mapping was also performed to assess the role of mobile genetic elements in harboring ARGs. Antimicrobial resistance genes were found to be statistically different between the type of cattle operation and Salmonella serotypes. Beef operations were statistically significantly associated with more ARGs compared to dairy operations. Salmonella Heidelberg, followed by Salmonella Dublin isolates, were associated with the most ARGs. Additionally, specific classes of ARGs were only present within mobile genetic elements.

Characterizing the influence of various antimicrobials used for metaphylaxis against bovine respiratory disease on host transcriptome responses.

Currently, control against bovine respiratory disease (BRD) primarily consists of mass administration of an antimicrobial upon arrival to facility, termed "metaphylaxis." The objective of this study was to determine the influence of six different antimicrobials used as metaphylaxis on the whole blood host transcriptome in healthy steers upon and following arrival to the feedlot. One hundred and five steers were stratified by arrival body weight (BW = 247 ± 28 kg) and randomly and equally allocated to one of seven treatments: negative control (NC), ceftiofur (CEFT), enrofloxacin (ENRO), florfenicol (FLOR), oxytetracycline (OXYT), tildipirosin (TILD), or tulathromycin (TULA). On day 0, whole blood samples and BW were collected prior to a one-time administration of the assigned antimicrobial. Blood samples were collected again on days 3, 7, 14, 21, and 56. A subset of cattle (n = 6) per treatment group were selected randomly for RNA sequencing across all time points. Isolated RNA was sequenced (NovaSeq 6,000; ~35 M paired-end reads/sample), where sequenced reads were processed with ARS-UCD1.3 reference-guided assembly (HISAT2/StringTie2). Differential expression analysis comparing treatment groups to NC was performed with glmmSeq (FDR ≤ 0.05) and edgeR (FDR ≤ 0.1). Functional enrichment was performed with KOBAS-i (FDR ≤ 0.05). When compared only to NC, unique differentially expressed genes (DEGs) found within both edgeR and glmmSeq were identified for CEFT (n = 526), ENRO (n = 340), FLOR (n = 56), OXYT (n = 111), TILD (n = 3,001), and TULA (n = 87). At day 3, CEFT, TILD, and OXYT shared multiple functional enrichment pathways related to T-cell receptor signaling and FcεRI-mediated NF-kappa beta (kB) activation. On day 7, Class I major histocompatibility complex (MHC)-mediated antigen presentation pathways were enriched in ENRO and CEFT groups, and CEFT and FLOR had DEGs that affected IL-17 signaling pathways. There were no shared pathways or Gene Ontology (GO) terms among treatments at day 14, but TULA had 19 pathways and eight GO terms enriched related to NF- κß activation, and interleukin/interferon signaling. Pathways related to cytokine signaling were enriched by TILD on day 21. Our research demonstrates immunomodulation and potential secondary therapeutic mechanisms induced by antimicrobials commonly used for metaphylaxis, providing insight into the beneficial anti-inflammatory properties antimicrobials possess.

Mycoplasma bovis is associated with Mannheimia haemolytica during acute bovine respiratory disease in feedlot cattle.

Bovine Respiratory Disease (BRD) represents a significant burden to the health of feedlot cattle and the profitability of the beef industry in the US. Mannheimia haemolytica is widely regarded as the primary bacterial pathogen driving acute BRD. While Mycoplasma bovis is most commonly implicated in chronic cases of BRD, this agent's potential role in acute stages of BRD is unclear. Therefore, this study aimed to evaluate potential associations between M. bovis and M. haemolytica during acute BRD in feedlot cattle. Nasal swabs (n = 1,044) were collected over time from feedlot cattle (n = 270) enrolled in an experiment assessing the effect of vaccination for Bovine Respiratory Syncytial Virus (BRSV). Swabs were analyzed for detection of M. bovis, M. haemolytica, Pasteurella multocida, Histophilus somni, and BRSV via multiplex qPCR assays. Data were analyzed using inverse conditional probability weighted (ICPW) logistic regression models to investigate potential effects of M. bovis presence on arrival (d0), day seven (d7) and day 14 (d14) post-arrival on M. haemolytica prevalence on day 28 (d28) post-arrival, adjusting for the previous history of P. multocida, H. somni, BRSV, BRD morbidity, and body weight. The potential association between time-to-BRD detection and M. bovis presence on d0, d7, and d14 post-arrival, was inferred via an ICPW time-to-event model. The presence of M. bovis in nasal swabs collected on d7 post-arrival was significantly associated with an increase in the prevalence of M. haemolytica on d28 (prevalence difference: 45%; 95% Confidence Interval: 31%, 60%; P-value < 0.001). Significant time-varying coefficients for M. bovis presence were detected at d0, d7, and d14 post-arrival in the ICPW time-to-event model (P-value < 0.001). The shortest median time-to-BRD detection was 29 days in cattle that were M. bovis positive on d0, d7, and d14 post-arrival and in those that were positive on d0 and d14 post-arrival. Under the conditions of this study, our findings suggest that M. bovis may be influencing the respiratory environment during the acute phase of BRD, increasing the abundance of M. haemolytica, which could have important impacts on the occurrence of BRD.

Clinical and microbiological effects in high-risk beef calves administered intranasal or parenteral modified-live virus vaccines.

Experimental bovine respiratory syncytial virus (BRSV) infection can enhance Histophilus somni (Hs) disease in calves; we thus hypothesized that modified-live virus (MLV) vaccines containing BRSV may alter Hs carriage. Our objective was to determine the effects of an intranasal (IN) trivalent (infectious bovine rhinotracheitis virus [IBRV], parainfluenza-3 virus [PI3V], and BRSV) respiratory vaccine with parenteral (PT) bivalent bovine viral diarrhea virus (BVDV) type I + II vaccine, or a PT pentavalent (BVDV type I and II, IBRV, BRSV, and PI3V) respiratory vaccine, on health, growth, immunity, and nasal pathogen colonization in high-risk beef calves. Calves (n = 525) were received in five truckload blocks and stratified by body weight (213 ± 18.4 kg), sex, and presence of a pre-existing ear-tag. Pens were spatially arranged in sets of three within a block and randomly assigned to treatment with an empty pen between treatment groups consisting of: 1) no MLV respiratory vaccination (CON), 2) IN trivalent MLV respiratory vaccine with PT BVDV type I + II vaccine (INT), or 3) PT pentavalent, MLV respiratory vaccine (INJ). The pen was the experimental unit, with 15 pens/treatment and 11 to 12 calves/pen in this 70-d receiving study. Health, performance, and BRSV, Hs, Mycoplasma bovis (Mb), Mannheimia haemolytica (Mh), and Pasteurella multocida (Pm) level in nasal swabs via rtPCR was determined on days 0, 7, 14, and 28, and BRSV-specific serum neutralizing antibody titer, and serum IFN-γ concentration via ELISA, were evaluated on days 0, 14, 28, 42, 56, and 70. Morbidity (P = 0.83), mortality (P = 0.68) and average daily gain (P ≥ 0.82) did not differ. Serum antibodies against BRSV increased with time (P < 0.01). There was a treatment × time interaction (P < 0.01) for Hs detection; on days 14 and 28, INT (21.1% and 57.1%) were more frequently (P < 0.01) Hs positive than CON (3.6% and 25.3%) or INJ (3.4 % and 8.4%). Also, INT had reduced (P = 0.03) cycle time of Hs positive samples on day 28. No difference (P ≥ 0.17) was found for IFN-γ concentration and Mb, Mh, or Pm detection. The proportion of Mh positive culture from lung specimens differed (P < 0.01); INT had fewer (0.0%; 0 of 9) Mh positive lungs than INJ (45.5%; 6 of 13) or CON (74.0%; 14 of 19). Vaccination of high-risk calves with MLV did not clearly impact health or growth during the receiving period. However, INT was associated with an altered upper respiratory microbial community in cattle resulting in increased detection and level of Hs.

Our objective was to determine the safety, efficiency, and effects on immunity and nasal shedding of respiratory pathogens for high-risk cattle administered an intranasal (IN), trivalent (infectious bovine rhinotracheitis virus [IBRV], parainfluenza-3 virus [PI3V], and bovine respiratory syncytial virus [BRSV]) respiratory vaccine with parenteral, bivalent bovine viral diarrhea virus (BVDV), or a parenteral, pentavalent (BVDV type I and II, IBRV, BRSV, and PI3V) respiratory vaccine, compared to an unvaccinated negative control. The results of this study indicate that modified-live virus (MLV) vaccination of high-risk calves upon arrival, either parenterally or intranasally, did not clearly impact health or growth during the feedlot receiving period. However, cattle that were intranasally vaccinated had increased carriage of Histophilus somni in the naris, greater amount of H. somni in nasal swabs indicated by reduced PCR cycle time, and less frequent culture of Mannheimia haemolytica from lung tissue samples upon necropsy. Therefore, intranasal administration of MLV vaccines may alter the microbial community and balance of opportunistic pathogens in the respiratory tract of cattle.

Association of Broiler Litter Microbiome Composition and Campylobacter Isolation.

Infection with Campylobacter species is one of the leading causes of bacterial diarrhea in humans in the US. Chickens, which become colonized on the farm, are important reservoirs of this bacterium. Campylobacter can establish itself in the broiler house via a variety of sources, can survive in the litter of the house, and possibly persist over successive flock cycles. However, the role of the broiler litter microbiome on Campylobacter persistence is not clear. A matched case-control study was conducted to determine whether the broiler litter microbiome composition was associated with Campylobacter isolation within the broiler house. Flocks were classified as cases when either Campylobacter jejuni or Campylobacter coli was isolated in boot sock samples, or as controls otherwise. Case and control flocks were matched at the broiler house level. Composite broiler litter samples were collected and used for DNA extraction and 16S rRNA gene V4 region sequencing. Reads were processed using the DADA2 pipeline to obtain a table of amplicon sequence variants. Alpha diversity and differential bacterial relative abundance were used as predictors of Campylobacter isolation status in conditional logistic regression models adjusting for flock age and sampling season. Beta diversity distances were used as regressors in stratified PERMANOVA with Campylobacter isolation status as predictor, and broiler house as stratum. When Campylobacter was isolated in boot socks, broiler litter microbiome richness and evenness were lower and higher, respectively, without reaching statistical significance. Campylobacter isolation status significantly explained a small proportion of the beta diversity (genus-level Aitchison dissimilarity distance). Clostridium and Anaerostipes were positively associated with Campylobacter isolation status, whereas Bifidobacterium, Anaerosporobacter, and Stenotrophomonas were negatively associated. Our results suggest the presence of bacterial interactions between Campylobacter and the broiler litter microbiome. The negative association of Campylobacter with Bifidobacterium, Anaerosporobacter, and Stenotrophomonas in litter could be potentially exploited as a pre-harvest control strategy.

Maternal HIV and child anthropometric outcomes over time: an analysis of Zimbabwe demographic health surveys.

OBJECTIVES: To understand the association between children's anthropometric measures and maternal HIV status in Zimbabwe and to determine whether these relationships changed over time. DESIGN: Data from Demographic Health Surveys in Zimbabwe rounds 2005, 2010, and 2015 were used to conduct cross-sectional analyses of child anthropometric measures (stunting, underweight, and wasting). METHODS: Using separate logistic regression models for each of the anthropometric measures, we estimated the adjusted prevalence odds ratio (OR) of stunting, underweight, and wasting in children according to maternal HIV status. Moreover, we evaluated an interaction by survey year to evaluate change over time. RESULTS: Children of mothers with HIV had 32% greater odds [OR = 1.32, 95% confidence interval (CI) 1.16-1.5] of stunting, 27% greater odds (OR = 1.27, 95% CI 1.1-1.48) of underweight status and 7% greater odds (OR = 1.07, 95% CI 0.81-1.42) of wasting status, than children of mothers without HIV. These associations between maternal HIV status and child undernutrition did not differ by year (P > 0.05 for all interaction terms). CONCLUSION: In Zimbabwe, having a mother who tested positive for HIV at the time of the survey has been associated with greater child undernutrition over the last two decades with no significant change by survey round. This emphasizes the need for continued programming to address nutritional deficiencies, sanitation, and infectious disease prevention in this high-risk population. The greatest impact of maternal HIV status has been on child stunting and underweight, associated with poor long-term child development.

Relationships among Fecal, Air, Oral, and Tracheal Microbial Communities in Pigs in a Respiratory Infection Disease Model.

The association of the lower respiratory tract microbiome in pigs with that of other tissues and environment is still unclear. This study aimed to describe the microbiome of tracheal and oral fluids, air, and feces in the late stage of Mycoplasma hyopneumoniae infection in pigs, and assess the association between the tracheal microbiome and those from air, feces, and oral fluids. Tracheal fluids (n = 73), feces (n = 71), oropharyngeal fluids (n = 8), and air (n = 12) were collected in seeder pigs (inoculated with M. hyopneumoniae) and contact pigs (113 days post exposure to seeder pigs). After DNA extraction, the V4 region from 16S rRNA gene was sequenced and reads were processed using Divisive Amplicon Denoising Algorithm (DADA2). Clostridium and Streptococcus were among the top five genera identified in all sample types. Mycoplasma hyopneumoniae in tracheal fluids was associated with a reduction of diversity and increment of M. hyorhinis, Glaesserella parasuis, and Pasteurella multocida in tracheal fluids, as well as a reduction of Ruminiclostridium, Barnesiella, and Lactobacillus in feces. Air contributed in a greater proportion to bacteria in the trachea compared with feces and oral fluids. In conclusion, evidence suggests the existence of complex interactions between bacterial communities from distant and distinct niches.

Survival analysis of two Mycoplasma hyopneumoniae eradication methods.

Mycoplasma hyopneumoniae is an important respiratory pathogen causing significant losses in the swine industry. Eradication of this bacterium from herds results in increased pig performance, productivity, and animal welfare. The objective of this study was to compare the time-to-detection of M. hyopneumoniae in breed-to-wean farms after the application of one of two methods for M. hyopneumoniae eradication. The two methods compared in this study were: 1) Herd closure and medication, and 2) Whole herd medication without extended closure. Fifty-six breed-to-wean farms located in the US Midwest constituted the cohort for this investigation. Herd closure and medication was applied in 45 farms, while whole herd medication was applied in 11 farms. Two mutually exclusive events were recorded for each farm, either detection of M. hyopneumoniae, which was considered the event of interest, or end of follow-up, which was the right-censored event. Farms were monitored until recording the event of interest, or until the end of follow-up, whichever occurred first. Detection of M. hyopneumoniae was assessed by identification of antibodies against the bacterium in sentinel pigs using a commercially available ELISA assay within 6 months post-eradication completion. Moreover, clinical presentation of disease was recorded if observed post-eradication completion. The censored event occurred at the end of the study in November 2016 (administrative censoring). Time-to-detection of M. hyopneumoniae was analyzed with a Cox proportional hazards model. The proportional hazards assumption was assessed using graphical methods. A sensitivity analysis to evaluate the assumption of outcome-independent censoring was also performed. The cumulative incidence of M. hyopneumoniae detection at the end of follow-up was 18.6 % (95% CI: 6.5%, 46.8%) for herd closure and medication, and 36.4% (95% CI: 15.5%, 70.3%) for whole herd medication. An interaction term between the type of eradication method and follow-up time was included in the model to account for the non-proportional hazards. An overall effect of eradication method was present (P = 0.0442). The hazard ratio associated to the time-invariant effect of eradication method was 29.2 (95% CI: 0.95, 894; P = 0.053). The hazard ratio associated with the interaction term was 0.88 (95% CI: 0.65, 1.2; P = 0.405). Under these conditions, eradication using herd closure and medication reduced the likelihood of detecting cases of M. hyopneumoniae in breed-to-wean farms compared to whole herd medication. Detection of M. hyopneumoniae was concentrated during the first 64 months of follow-up in herd closure and medication, and in the first 8 months in whole herd medication.

Natural transmission and detection of Mycoplasma hyopneumoniae in a naïve gilt population.

Mycoplasma hyopneumoniae (M. hyopneumoniae) continues to be a prevalent and economically important swine respiratory pathogen. For M. hyopneumoniae surveillance, blood samples and/or oral fluids are commonly collected from incoming replacement gilts prior to entering sow farms. However, limitations to this approach exist, particularly due to low sensitivity during acute stages of natural infection, leading to diagnostic uncertainty. Therefore, the objective of this study was to evaluate the natural transmission and detection of M. hyopneumoniae based on the introduction of one infected gilt to a naïve population. Twenty-nine naïve gilts were housed with one M. hyopneumoniae naturally exposed gilt for 8 weeks. Deep tracheal catheters, laryngeal swabs, and blood samples were individually collected from each gilt at 0, 1, 2, 4, 6, and 8 weeks post-contact (wpc), along with one pen-based oral fluid sample. Blood samples were assayed by ELISA, while all other samples were tested by real-time PCR. The transmission rate of M. hyopneumoniae (ꞵ) was estimated using a Bayesian mixed-effects generalized linear model. At 8 wpc, 27 % (8/29) of the naïve gilts had become infected (ꞵ = 0.73 new infected gilts/gilt-week). Seroconversion was detected in 3% of contact gilts at 8 wpc. Oral fluids were negative for M. hyopneumoniae at all samplings. In this study, the natural transmission of M. hyopneumoniae was slow and detection varied based on sample type and timing. Thus, M. hyopneumoniae surveillance protocols should include lower respiratory tract samples that are tested by real-time PCR to avoid the introduction of potentially infected gilts into naïve sow farms.

Global assessment of national mandatory vaccination policies and consequences of non-compliance.

BACKGROUND: Declining vaccination coverage and increasing hesitancy is a worldwide concern. Many countries have implemented mandatory vaccination policies to promote vaccination. However, mandatory vaccination policies differ significantly by country. Beyond case studies, no comprehensive study has compared these policies or the penalties for non-compliance on a global scale. METHODS: We conducted extensive keyword, policy, and literature searches to identify mandatory national vaccination policies globally and develop a comprehensive database. A mandatory national vaccination policy was defined as a policy from a national authority that requires individuals to receive at least one vaccination based on age or to access a service. Two reviewers independently evaluated evidence for a mandate and whether non-compliance penalties were incorporated. We categorized penalties into four types, based on the nature of the penalty. These penalties impact an individual's financial, parental rights, educational (i.e., child's school entry and access), and liberty status. We rated the severity within each category. RESULTS: Of 193 countries investigated, 54% (n = 105) had evidence of a nationwide mandate as of December 2018. The frequency, types, and severity of penalties varied widely across all regions. We found that 59% (n = 62) of countries with national mandates defined at least one penalty for non-compliance with a vaccine mandate. Among those, educational penalties (i.e., limiting a child's entry or ongoing access to school) were the most common (69%; n = 43), with most countries with educational penalties refusing school enrollment until vaccination requirements are met (81%; n = 35). CONCLUSION: We undertook a comprehensive assessment of national mandatory vaccination policies and identified a diversity of penalties in place to promote compliance. Our results highlight the need to critically evaluate the implementation of non-compliance penalties in order to determine their effectiveness and to define best practices for sustaining high vaccination uptake worldwide.

Mycoplasma hyopneumoniae genetic variability within swine production flows.

The aim of this study was to assess the genetic variability of Mycoplasma hyopneumoniae within various swine production flows. Four M. hyopneumoniae positive production flows, composed of 4 production stages, were selected for this study. Laryngeal and/or bronchial swabs were collected from each production stage within a flow, for a period of 4 months up to 3 years. A multiple-locus variable-number tandem repeat analysis was performed to assess the genetic variation of M. hyopneumoniae within and across production flows through the identification of variable-number tandem repeat (VNTR) types. A maximum of 6 M. hyopneumoniae VNTR types were identified in a single flow, in which VNTR types appeared to be flow specific. An identical VNTR type was detected across several production stages for up to 3 years. In this study, minimal M. hyopneumoniae genetic variation was evidenced within and across production flows.

L'objectif de cette étude était d'évaluer la variabilité génétique de Mycoplasma hyopneumoniae au sein de différents flux de production porcine. Quatre flux de production positifs pour M. hyopneumoniae, composés de quatre stades de production, furent sélectionnés pour cette étude. Des écouvillons laryngés et/ou bronchiaux furent prélevés de chaque stade de production à l'intérieur d'un flux, pour une période de 4 mois jusqu'à 3 ans. Une analyse multi-locus du polymorphisme des séquences répétées en tandem fut effectuée afin d'évaluer la variation génétique de M. hyopneumoniae au sein et à travers les flux de production par l'identification des types de polymorphismes de séquences répétées en tandem (VNTR). Un maximum de six types de VNTR de M. hyopneumoniae fut identifié dans un flux unique, dans lequel les types de VNTR apparaissaient être spécifiques de flux. Un type de VNTR identique fut détecté à travers plusieurs stades de production et jusqu'à 3 ans. Dans cette étude, une variation génétique minime de M. hyopneumoniae fut notée au sein et à travers des flux de production.(Traduit par Docteur Serge Messier).

Virulence factors and antibiograms of Escherichia coli isolated from diarrheic calves of Egyptian cattle and water buffaloes.

Diarrhea caused by Escherichia coli in calves is an important problem in terms of survivability, productivity and treatment costs. In this study, 88 of 150 diarrheic animals tested positive for E. coli. Of these, 54 samples had mixed infection with other bacterial and/or parasitic agents. There are several diarrheagenic E. coli pathotypes including enteropathogenic E. coli (EPEC), Shiga-toxin producing E. coli (STEC), enterotoxigenic E. coli (ETEC) and necrotoxigenic E. coli (NTEC). Molecular detection of virulence factors Stx2, Cdt3, Eae, CNF2, F5, Hly, Stx1, and ST revealed their presence at 39.7, 27.2, 19.3, 15.9, 13.6, 9.0, 3.4, and 3.4 percent, respectively. As many as 13.6% of the isolates lacked virulence genes and none of the isolate had LT or CNF1 toxin gene. The odds of isolating ETEC from male calves was 3.6 times (95% CI: 1.1, 12.4; P value = 0.042) that of female calves, whereas the odds of isolating NTEC from male calves was 72.9% lower (95% CI: 91.3% lower, 15.7% lower; P value = 0.024) than that in females. The odds of isolating STEC in winter was 3.3 times (95% CI: 1.1, 10.3; P value = 0.037) that of spring. Antibiograms showed 48 (54.5%) of the isolates to be multi-drug resistant. The percent resistance to tetracycline, streptomycin, ampicillin, and trimethoprim-sulfamethoxazole was 79.5, 67.0, 54.5, and 43.0, respectively. Ceftazidime (14.8%), amoxicillin-clavulanic acid (13.6%) and aztreonam (11.3%) showed the lowest resistance, and none of the isolates was resistant to imipenem. The results of this study can help improve our understanding of the epidemiological aspects of E. coli infection and to devise strategies for protection against it. The prevalence of E. coli pathotypes can help potential buyers of calves to avoid infected premises. The antibiograms in this study emphasizes the risks associated with the random use of antibiotics.

Relationship among damaged chromatin, motility and viability in cryopreserved spermatozoa from Brahman bulls / Relación entre la alteración de la cromatina, movilidad y viabilidad en espermatozoides criopreservados de toros Brahman / Relação entre a alteração da cromatina, motilidade e viabilidade dos espermaotozoides criopreservados de touros Brahman

The aim of this study was to determine the percentage of sperm with damaged chromatic measure with toluidine blue stain and it´s relationship with motility and viability in criopreserverd semen from Brahman bulls. Three ejaculates from six Brahman bulls were used. Immediately after thawing, sperms were stained with toluidine blue to establish chromatin integrity (sperms with normal chromatin were light blue or green while sperms with damaged chromatin were dark blue or violet). Sperms were also stained with eosin-nigrosin to determine viability (live sperms were unstained while dead sperms were pink). Motility was measured under light microscope. Effects of bull, ejaculate, and the interaction between variables were assessed. The percentage of live sperms was 50.02 ( ± 14.13%). The mean motility was 33.88 (± 12.43%), while the percentage of sperms with damaged chromatin was 4.17 ( ± 2.96%). Viability was positively correlated with motility (r=0.77217, p=0.0002), and negatively correlated with damaged chromatin sperms (r= -0.43104, p=0.0087). Motility percentage was negatively correlated with the percentage of sperms with damaged chromatin (r=-0.48337, p=0.0421). In conclusion, cryopreserved semen of Brahman bulls presented a low level of chromatin damage, and this trait was negatively correlated with sperm motility and viability.

El objetivo del presente trabajo fue determinar el porcentaje de espermatozoides con cromatina dañada medida con la tinción de azul de toluidina, y su relación con la motilidad y la vitalidad del semen criopreservado de toros Brahma. Para ello, se utilizó semen de tres eyaculados de seis toros Brahman, el cual una vez descongelado se procedió a teñir con azul de toluidina para determinar la integridad de la cromatina (espermatozoides con cromatina normal teñidos de azul o verde claro; espermatozoides con cromatina anormal teñidos de azul oscuro o violeta), también se tiñeron con eosinanigrosina para determinar la viabilidad (espermatozoides vivos permanecen blancos; espermatozoides muertos se tiñen de rosado) y se estimó la motilidad espermática mediante microscopía óptica. Se evidenciaron las diferencias en todos los parámetros evaluados debidas al efecto toro y al eyaculado, así como a la interacción entre estas dos variables. El porcentaje de espermatozoides vivos fue de 50.02 ± 14.13% y la motilidad espermática promedió un 33.88 ± 12.43%, mientras que el porcentaje de espermatozoides con cromatina dañada fue de 4.17 ± 2.96%. El porcentaje de espermatozoides vivos se correlacionó positivamente con la motilidad (r=0.77217, p=0.0002), y negativamente con el porcentaje de espermatozoides con cromatina dañada (r= -0.43104, p=0.0087), mientras que el porcentaje de motilidad se correlacionó negativamente con el porcentaje de espermatozoides con cromatina anormal (r= -0.48337, p=0.0421). En conclusión, el semen criopreservado de toros Brahman presenta un bajo nivel de espermatozoides con daño en la cromatina, lo cual se correlaciona negativamente con la motilidad y la vitalidad espermática.

O objectivo deste estudo foi determinar a percentagem de espermatozóides com cromatina danificada, determinada pela coloração com azul de toluidina e sua relação com a viabilidade e a mobilidade do esperma cripreservado de touros Brahman. Para isso, foram utilizados três ejaculados de sêmen de seis touros Brahman, que uma vez descongelado foram coradas com azul de toluidina para determinar a integridade da cromatina (espermatozóides com cromatina normal coloream de azul ou verde; cromatina de espermatozóides con cromatina danificada, coloream de azul escuro ou violeta). Também foram corados com eosina nigrosina para determinar a viabilidade (espermatozóides vivos permanecem brancos e os mortos de cor rosa) e a motilidade espermática foi estimada por microscopia de luz. Foram encontradas diferenças significativas em todos os parâmetros, devido ao efeito de touro e o ejaculado, bem como a interacção entre essas duas variáveis. A percentagem de espermatozóides vivos foi de 50.02 ± 14.13% e motilidade espermática média de 33.88 ± 12.43%, enquanto a percentagem de espermatozóides com cromatina danificada foi de 4.17 ± 2.96%. A percentagem de espermatozóides vivos foi positivamente correlacionada com a motilidade (r=0.77217, p=0.0002) e negativamente com a porcentagem de espermatozóides com cromatina danificada (r = -0.43104, p= 0.0087), enquanto que a percentagem de motilidade correlacionou negativamente com a percentagem de espermatozóides com cromatina danificada (r = -0.48337, p=0.0421). Em conclusão, o sêmen de touros Brahman criopreservados tem um baixo nível de dano da cromatina, que está correlacionada negativamente com a motilidade e a vitalidade do esperma.