Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 3.455
Filtrar
1.
Anticancer Res ; 40(8): 4701-4706, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32727795

RESUMO

BACKGROUND/AIM: Bovine mastitis is caused by the invasion and propagation of pathogenic microorganisms into the udder and mammary gland tissues of cattle. In this study, the therapeutic effect of a low-molecular-weight whey protein (LMW-WP) on bovine mastitis was evaluated. MATERIALS AND METHODS: LMW-WP was orally, intraperitoneally, and vaginally administered to bovine with mastitis. The number of somatic cells in milk was measured 24 h before the administration of LMW-WP. The effect of LMW-WP on cytokine production was measured with a microarray that evaluates the expression of cytokines. RESULTS: In the group that received 1,000 mg intraperitoneally, the somatic cell count was reduced to less than 400,000 at the shipment standard value in three of the four udders, indicating 75% efficacy. The group that received 1,000 mg by vaginal administration showed 67% efficacy. It was confirmed that LMW-WP increased the production of cytokines such as IL-5, IL-6, IL-9, IL-12, MCP-1, and VEGF in mouse macrophage cells, but it did not show any antibacterial activity. CONCLUSION: LMW-WP may be an effective therapeutic agent for bovine mastitis.


Assuntos
Macrófagos/efeitos dos fármacos , Mastite Bovina/tratamento farmacológico , Proteínas do Soro do Leite/farmacologia , Animais , Antibacterianos/farmacologia , Bovinos , Contagem de Células/métodos , Linhagem Celular , Citocinas/metabolismo , Feminino , Glândulas Mamárias Animais/metabolismo , Mastite Bovina/microbiologia , Camundongos , Leite/metabolismo , Células RAW 264.7
2.
Anim Sci J ; 91(1): e13406, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32578314

RESUMO

The present study assessed the effects of intramammary infusion of Bifidobacterium breve (B. breve) on mastitis-causing pathogens and on the somatic cell counts (SCC) in lactating cows with chronic subclinical mastitis. The bacteriological cure rates of 42 quarters from 42 cows infected with Staphylococcus aureus, Corynebacterium bovis, coagulase-negative staphylococci, and environmental streptococci were 18.2% (2/11), 14.3% (1/7), 58.8% (10/17), and 28.6% (2/7), respectively, on day 14 after B. breve infusion. In a second trial, B. breve was infused into 18 quarters from 18 cows with chronic subclinical mastitis from which pathogens had not been isolated; the rates of quarters showing SCC > 50 × 104 cells/ml prior to B. breve infusion that decreased to < 30 × 104 cells/ml after infusion were significantly (p < .01) increased to 61.1% (11/18) on day 14 compared to that prior to infusion (0/18). The intramammary infusion of B. breve appears to be a non-antibiotic approach for elimination of minor pathogens and decreasing SCC in quarters with chronic subclinical mastitis in dairy cows.


Assuntos
Bifidobacterium breve , Infecções por Corynebacterium , Glândulas Mamárias Animais/citologia , Glândulas Mamárias Animais/microbiologia , Mastite Bovina/microbiologia , Mastite Bovina/terapia , Infecções Estafilocócicas , Animais , Bovinos , Corynebacterium , Infecções por Corynebacterium/veterinária , Feminino , Infusões Intralesionais , Infecções Estafilocócicas/veterinária , Staphylococcus aureus , Resultado do Tratamento
3.
Int J Syst Evol Microbiol ; 70(7): 4105-4110, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32589570

RESUMO

A polyphasic taxonomic study was performed on an unidentified Arcanobacterium-like Gram-stain-positive bacterium designated strain C605018/01/1T isolated from a milk sample collected from the udder of a cow at post mortem. Comparative 16S rRNA gene sequencing showed that the bacterium belonged to the genus Arcanobacterium and was most closely related to the type strain of Arcanobacterium pluranimalium (99.76 %); sequence similarities to all other Arcanobacterium species were below 97 %. The wet-lab DNA-DNA hybridization values among strain C605018/01/1T and A. pluranimalium DSM 13483ᵀ were low, 16.9 % (reciprocal, 49.8 %). Pertaining to the whole genome sequence with a total length of 2.02 Mb and 1654 protein counts, the novel strain C605018/01/01T displayed a G+C content of 51.6 % mol%. The presence of the major menaquinone MK-9(H4) supported the affiliation of this strain to the genus Arcanobacterium. The polar lipid profile consisted of the major components diphosphatidylglycerol, phosphatidylcholine, phosphatidylinositol, phosphatidylinositol-mannoside and unidentified glycolipid and aminophospholipids. Based on these results it is proposed that strain C605018/01/1T should be classified as representing a novel species, Arcanbacterium bovis sp. nov. The type strain C605018/01/1T (CCUG 45425T=DSM 107286T=BCCM/LMG 30783T).


Assuntos
Arcanobacterium/classificação , Mastite Bovina/microbiologia , Leite/microbiologia , Filogenia , Animais , Arcanobacterium/isolamento & purificação , Técnicas de Tipagem Bacteriana , Composição de Bases , Bovinos , DNA Bacteriano/genética , Ácidos Graxos/química , Feminino , Glicolipídeos/química , Hibridização de Ácido Nucleico , Fosfolipídeos/química , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Vitamina K 2/análogos & derivados , Vitamina K 2/química , Sequenciamento Completo do Genoma
4.
J Dairy Sci ; 103(7): 6569-6575, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32331896

RESUMO

The main objective of this study was to evaluate the barrier characteristics of 3 external teat sealants for dry cows in preventing bacterial penetration by 3 common major mastitis pathogens (Escherichia coli, Staphylococcus aureus, and Streptococcus uberis) via a novel in vitro simulation model using rubber calf-feeding nipples. All feeding nipples were filled with a sterile cotton plug soaked in sterile broth heart infusion medium and were treated as follows: rubber teats 1 and 5 were sealed with Ubera Dry (Inovet, Arendonk, Belgium); rubber teats 2 and 6 were sealed with T-Hexx Dry (Huvepharma Livestock, St. Louis, MO); rubber teats 3 and 7 were sealed with Uddergold Dry (Ecolab Food and Beverage Division, St. Paul, MN); and rubber teats 4 and 8 remained unsealed and served as positive and negative controls, respectively. After the dips had dried, rubber teats 1 to 4 were immersed in a suspension of E. coli (experiment 1), Staph. aureus (experiment 2), or Strep. uberis (experiment 3; ≥1.5 × 108 cfu/mL) for 24 h, whereas rubber teats 5 to 8 were not exposed to the bacterial suspensions. All external teat sealants adhered well to the rubber teats. All cotton plugs collected from the teats that were not exposed to E. coli, Staph. aureus, or Strep. uberis (rubber teats 5 to 8) remained culture-negative, except for 1 (due to contamination). Of the rubber teats that were exposed to the major mastitis pathogens, all cotton plugs collected from the teats dipped with Ubera Dry and T-Hexx Dry remained culture-negative for the mastitis pathogen they were exposed to. The cotton plugs of the rubber teats that were sealed with Uddergold Dry and exposed to E. coli and Strep. uberis showed positive cultures for the respective bacteria, as demonstrated using strain-typing. The cotton plugs collected from the rubber teats that were not sealed with an external teat sealant and that served as positive controls became culture-positive for the mastitis pathogens they were exposed to. We conclude that Ubera Dry showed comparable and superior barrier performance against penetration of E. coli, Staph. aureus, and Strep. uberis compared with T-Hexx Dry and Uddergold Dry, respectively, under in vitro conditions using a novel in vitro simulation model. Although one should be aware that the method has not yet been validated to predict risk of intramammary infections, the proposed technique can be a meaningful starting point to evaluate and compare the barrier characteristics of external teat sealants in preventing bacterial penetration. A large-scale clinical trial is needed before any definite conclusions can be drawn as to the adherence, duration of adherence, barrier performance, and efficacy in protection against intramammary infections of the 3 external teat sealants under field conditions.


Assuntos
Anti-Infecciosos Locais/administração & dosagem , Escherichia coli/fisiologia , Mastite Bovina/prevenção & controle , Staphylococcus aureus/fisiologia , Staphylococcus/fisiologia , Animais , Bélgica , Bovinos , Indústria de Laticínios , Feminino , Glândulas Mamárias Animais/microbiologia , Mastite Bovina/microbiologia , Borracha
5.
Microbiol Res ; 236: 126443, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32146293

RESUMO

Recently, the characteristics of prevalent bacterial pathogens causing bovine mastitis have become increasingly complicated, and many commensal or unusual bacterial species have been isolated from milk samples of cows with mastitis. Strain JS20170427COW was isolated dominantly from the milk of Holstein Friesian cows with mastitis in Jiangsu province in China. Colonies of this strain showed a hillock-like protrusion, with a pale-yellow color at the protrusion and a transparent edge, 4-5 mm in diameter after cultivation at 37 °C for 24 h on 5% sheep blood-enriched agar. Although 16 s rRNA analysis showed the closest relationship with the family Flavobacteriaceae containing Elizabethkingia spp., Riemerella sp. and Soonwooa buanensis, the bacterial species of strain JS20170427COW could not be identified adequately because it had a sequence identity of less than 95 % in 16 s rRNA when compared with all the known species of the family Flavobacteriaceae. Unexpectedly, both the first and re-sequencing data determined the whole genome size of strain JS20170427COW to be 2.69 Mb, which is different from the above three closest bacterial species. Therefore, we hypothesized that strain JS20170427COW is a novel taxon of Flavobacteriaceae. Further identification using conserved genes, single-nucleotide polymorphisms (SNPs), phylogenetic and average nucleotide identity analyses based on whole genome data suggested that JS20170427COW was more likely to be an Elizabethkingia-like strain, but that it does not belong to the Elizabethkingia genus. Comparison of the predicted open reading frames (ORFs) revealed that strain JS20170427COW encodes more special genes than Elizabethkingia species. In summary, we identified a novel Flavobacteriaceae taxon showing a close relationship with Elizabethkingia subspecies, which has potential pathogenicity in bovine mastitis.


Assuntos
Infecções por Flavobacteriaceae/diagnóstico , Flavobacteriaceae , Mastite Bovina/microbiologia , Animais , Técnicas de Tipagem Bacteriana , Bovinos , Doenças dos Bovinos/microbiologia , China , DNA Bacteriano/genética , Feminino , Flavobacteriaceae/classificação , Flavobacteriaceae/genética , Flavobacteriaceae/isolamento & purificação , Filogenia , RNA Ribossômico 16S/genética
6.
J Vet Med Sci ; 82(4): 488-493, 2020 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-32132316

RESUMO

A cross-sectional study was conducted to investigate the risk factors for sub-clinical mastitis (SCM) in Mbarara District, an intensive dairy production region of Uganda where hand-milking is dominant. In 30 farms, herd-level milking practices and SCM prevalence were studied. The SCM prevalences were 68.6% (417/608, 95% confidence interval (CI): 64.9-72.2%) and 39.2% (946/2,411, 37.3-41.2%) at the cow- and quarter-levels, respectively. A preventive factor for SCM was cow calmness at the end of milking (OR: 0.20, 95%CI: 0.05-0.79, P=0.021); a risk factor was rough teat-end (OR: 1.75, 95%CI: 1.14-2.68, P=0.011). Good cow hygiene was negatively associated with environmental mastitis (P=0.002). Appropriate hand-milking practices that avoid teat damage are expected to reduce SCM in Uganda.


Assuntos
Indústria de Laticínios/métodos , Mastite Bovina/epidemiologia , Criação de Animais Domésticos/métodos , Animais , Infecções Assintomáticas/epidemiologia , Bactérias/isolamento & purificação , Comportamento Animal , Bovinos , Estudos Transversais , Feminino , Glândulas Mamárias Animais , Mastite Bovina/etiologia , Mastite Bovina/microbiologia , Leite/microbiologia , Prevalência , Fatores de Risco , Uganda/epidemiologia
7.
J Dairy Sci ; 103(5): 4732-4737, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32113752

RESUMO

Staphylococcus aureus is an important intramammary pathogen for dairy cows that also is remarkably important for public health. Multiple virulence factors can be involved simultaneously during the pathogenesis of a staphylococcal disease, including adhesion proteins, extracellular enzymes, and toxins. The main objective of this study was to assess virulence factors that are associated with cow intramammary infection (IMI) and of human health concern among Staph. aureus isolates obtained from bulk tank milk (BTM) and adherences on milking equipment surfaces. A total of 166 Staph. aureus isolates from 23 dairy farms were characterized according to their virulence profiles. For virulence factors of importance in IMI, the presence of the virulence markers thermonuclease (nuc) and coagulase (coa) and virulence genes such as fibronectin (fnbA) and intercellular adhesion (icaA, icaD) were assessed. For virulence factors of public health concern, presence of antimicrobial resistance (mecA and mecC) and enterotoxin (sea and seb) genes were analyzed. Among all Staph. aureus isolates, 5 virulence profiles were found; the profile nuc(+)coa(+)fnbA(+)icaA(+)icaD(+)mecA(-)mecC(-)sea(-)seb(-) was the most frequently observed (21 out of 23 dairy farms). No differences were found between the virulence profile frequencies of Staph. aureus from BTM and adherences on milking equipment surfaces. The virulence profiles most frequently observed included genes involved in the adherence and biofilm-forming ability of Staph. aureus, which could represent a potential advantage for the bacterium during the early stages of IMI colonization and for persistence on surfaces. Our results indicate a greater frequency of virulence factors of importance for IMI pathogenesis than virulence factors of public health concern, consistent with the dairy origin of isolates. The mecA, mecC, and seb genes were not observed among Staph. aureus isolates analyzed in this study. However, the sea gene was detected in 3 Staph. aureus isolated from BTM, thus posing a potential public health threat. Our results emphasize the importance of understanding the epidemiology and dynamics of Staph. aureus on dairy farms as a tool for the improvement of udder health and milk safety.


Assuntos
Biofilmes/crescimento & desenvolvimento , Mastite Bovina/microbiologia , Leite/microbiologia , Infecções Estafilocócicas/veterinária , Staphylococcus aureus/patogenicidade , Fatores de Virulência/genética , Animais , Bovinos , Chile , Coagulase/genética , Indústria de Laticínios/instrumentação , Enterotoxinas/genética , Fazendas , Feminino , Glândulas Mamárias Animais/microbiologia , Nuclease do Micrococo/genética , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus/isolamento & purificação , Staphylococcus aureus/fisiologia , Virulência
8.
J Dairy Sci ; 103(5): 4588-4605, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32113759

RESUMO

Staphylococcus aureus is one of the pathogens most frequently isolated from cases of mastitis worldwide. To decrease the effect of S. aureus mastitis in dairy farming, alternative strategies for controlling mastitis are needed that depend on a better knowledge of cow-to-cow variations in S. aureus antibody production. The present study sought to explore the diversity of S. aureus antibodies produced by dairy cows with a distinct mastitis history and vaccinated with a polyvalent mastitis vaccine. We obtained protein extracts from S. aureus isolates derived from persistent subclinical mastitis. Proteins were fractionated using 2-dimensional gel electrophoresis and Western blotting. Then, Western blotting membranes were exposed to sera from 24 dairy cows that had been divided into the following groups: vaccinated dairy cows that were infected with S. aureus, further subdivided according to whether they (a) remained infected by S. aureus or (b) recovered from the intramammary infection; unvaccinated dairy cows infected with S. aureus; and vaccinated healthy dairy cows with no history of S. aureus mastitis. Proteins found to be reactive by Western blot were identified by mass spectrometry (MALDI/TOF-TOF). Our most important finding was that F0F1 ATP synthase subunit α, succinyl-diaminopimelate desuccinylase, and cysteinyl-tRNA synthetase were potential candidate proteins for the prevention of S. aureus mastitis. This study strengthens the notion that variations among animals should not be ignored and shows that the heterogeneity of antibody production against anti-staphylococcal antigens in animals may enable the identification of new immunotherapy targets.


Assuntos
Anticorpos Antibacterianos/sangue , Mastite Bovina/imunologia , Infecções Estafilocócicas/veterinária , Vacinas Antiestafilocócicas/administração & dosagem , Staphylococcus aureus/imunologia , Animais , Anticorpos Antibacterianos/imunologia , Bovinos , Feminino , Humanos , Mastite Bovina/microbiologia , Mastite Bovina/prevenção & controle , Leite , Infecções Estafilocócicas/imunologia , Infecções Estafilocócicas/microbiologia , Vacinas Antiestafilocócicas/imunologia
9.
Vet Microbiol ; 242: 108570, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32122584

RESUMO

This study investigated the continuous monthly prevalence of bovine clinical mastitis (CM) and the distribution of causative pathogens among 36,619 CM milk samples from large dairy farms across seven Chinese provinces from 2015 to 2017 using data from routine CM recording systems. Based on treatment period and cost per cow, withdrawal period, daily milk production, and milk value data from each farm in 2017, we calculated the economic impact of CM at the farm level with 2578-9044 lactating cows per farm. Results showed a wide variation in monthly prevalence of CM (0.6 %-18.2 %) among the seven farms over the study period, indicating regional and temporal differences in the occurrence of CM in China. Enterobacteriaceae were the predominant pathogens across all farms from six provinces except Shandong, in which the Streptococcus spp. was the most prevalent. However, the distribution of various Enterobacteriaceae species differed among farms, and Streptococcus species distribution was strongly associated (Pearson's coefficient, 68.4 %) with location. Monthly economic losses associated with CM showed clear variation, ranging from 12,000-76,000 USD/farm/month. Sensitivity analysis showed that economic loss at the farm level was most sensitive to variation in the prevalence of CM, followed by antibiotic treatment period and daily milk production per cow. To our knowledge, this is the longest running study of CM and the first estimation of its economic impacts in China. Our findings highlight the considerable costs associated with mastitis, and indicate that preventive measures and regional and timely treatment of CM are needed.


Assuntos
Indústria de Laticínios/economia , Infecções por Enterobacteriaceae/veterinária , Mastite Bovina/epidemiologia , Mastite Bovina/microbiologia , Animais , Bovinos/microbiologia , China/epidemiologia , Enterobacteriaceae/isolamento & purificação , Enterobacteriaceae/patogenicidade , Infecções por Enterobacteriaceae/economia , Infecções por Enterobacteriaceae/epidemiologia , Fazendas/estatística & dados numéricos , Feminino , Mastite Bovina/economia , Prevalência , Streptococcus/isolamento & purificação , Streptococcus/patogenicidade
10.
Vet Microbiol ; 242: 108592, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32122596

RESUMO

A number of veterinary clinical pathology laboratories in New Zealand have been reporting emergence of increased minimum in inhibitory concentrations for ß-lactams in the common clinical bovine mastitis pathogen Streptococcus uberis. The objective of this study was to determine the genetic basis of this increase in MIC for ß-lactams amongst S. uberis. Illumina sequencing and determination of oxacillin MIC was performed on 265 clinical isolates. Published sequences of the five penicillin binding proteins pbp1a, pbp1b, pbp2a, pbp2b, and pbp2x were used to identify, extract and align these sequences from the study isolates. Amino acid substitutions resulting from single nucleotide polymorphisms (SNP) within these genes were analysed for associations with elevated (≥ 0.5 mg/L) oxacillin MIC together with a genome wide association study. The population structure of the study isolates was approximated using a phylogenetic tree generated from an alignment of the core genome. A total of 53 % of isolates had MIC ≥ 0.5 mg/L for oxacillin. A total of 101 substitutions within the five pbp were identified, of which 11 were statistically associated with an MIC ≥ 0.5 mg/L. All 140 isolates which exhibited an increased ß-lactam MIC had SNPs leading to pbp2x E381K and Q554E substitutions. The phylogenetic tree indicated that the genotype and phenotype associated with the increased MIC for oxacillin were present in several different lineages suggesting that acquisition of this increased ß-lactam MIC had occurred in multiple geographically distinct regions. Reanalysis of the data from the intervention studies from which the isolates were originally drawn found a tendency for the pbp2x E381K substitution to be associated with lower cure rates. It is concluded that there is geographically and genetically widespread presence of pbp substitutions associated with reduced susceptibility to ß-lactam antimicrobials. Additionally, presence of pbp substitutions tended to be associated with poorer cure rate outcomes following antimicrobial therapy for clinical mastitis.


Assuntos
Antibacterianos/farmacologia , Mastite Bovina/microbiologia , Streptococcus/efeitos dos fármacos , Streptococcus/genética , Resistência beta-Lactâmica/genética , Substituição de Aminoácidos , Animais , Proteínas de Bactérias/genética , Bovinos , Feminino , Estudo de Associação Genômica Ampla , Testes de Sensibilidade Microbiana , Nova Zelândia , Oxacilina/farmacologia , Proteínas de Ligação às Penicilinas/genética , Filogenia , Polimorfismo de Nucleotídeo Único
11.
Vet Microbiol ; 242: 108594, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32122598

RESUMO

Non-S. aureus staphylococci (NAS) are the most frequently isolated pathogens from bovine milk and can cause intramammary infections (IMI). They can also be found in teat canals, on bovine skin and in cows' environment, which may lead to unnoticed contamination of milk samples. The aim of this study was to investigate the role of NAS species as mastitis-causing pathogens or contaminants, and to identify possible differences between NAS species. A longitudinal study was conducted with consecutive milk sampling in five German dairy herds. Species identification was performed using matrix-assisted laser desorption ionization-time of flight mass spectrometry. Infections were distinguished from contaminations using two different definitions based on the repeated detection of an NAS species. Of 15 NAS species found, eight and ten, respectively, were associated with an IMI. Staphylococcus simulans and S. chromogenes were associated with IMI in more than 90 % of the findings. S. warneri, S. xylosus, S. microti, S. haemolyticus, and S. succinus seem to be frequent causes of IMI as well as contaminants. If a species-differentiation is available after cultivating NAS, the findings should be interpreted in consideration of the observations made in this study, whether it is more likely a question of a contaminant or a cause of intramammary infection. The bacteria shedding intensity of the NAS species with a more substantially adverse effect on udder health seems to be higher than that of the less important NAS pathogens.


Assuntos
Contaminação de Alimentos/análise , Glândulas Mamárias Animais/microbiologia , Mastite Bovina/microbiologia , Leite/microbiologia , Infecções Estafilocócicas/veterinária , Staphylococcus/isolamento & purificação , Animais , Derrame de Bactérias , Bovinos , Contagem de Colônia Microbiana , Indústria de Laticínios , Feminino , Alemanha , Inflamação , Estudos Longitudinais , Mastite Bovina/diagnóstico , Infecções Estafilocócicas/diagnóstico , Staphylococcus/classificação , Staphylococcus aureus
12.
Vet Microbiol ; 242: 108608, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32122612

RESUMO

We aimed to identify the dynamics of the within-herd prevalence of Mycoplasma (M.) bovis intramammary infection (IMI) in four dairy herds, estimate prevalence of M. bovis in colostrum and clinical mastitis cases and compare M. bovis strains from calves' respiratory and cow clinical mastitis samples. Within a six-month study period, cow composite milk samples (CMS) were collected three times during routine milk recording, first milking colostrum samples from all calving cows and udder quarter milk samples from clinical mastitis cases. Calf respiratory samples were collected from calves with respiratory disease. Pooled milk samples were analysed for M. bovis with the Mastitis 4B polymerase chain reaction (PCR) test kit (DNA Diagnostic A/S). Prevalence estimates were calculated with Bayesian framework in R statistical programme. cg-MLST was used for M. bovis genotyping. In Herd I and II first testing M. bovis IMI within-herd prevalence (95 % credibility interval (CI)) was 4.7 % (2.9; 6.8) and 3.4 % (2.3; 4.6), changing to 1.0 % (0.1; 1.7) and 0.8 % (0.1; 1.4) in Herd I and 0.4 % (0.0; 0.7) in Herd II at the next samplings. In Herd III and IV first testing M. bovis IMI within-herd prevalence was 12.3 % (9.7; 15.2) and 7.8 % (6.2; 9.5), changing to 4.6 % (3.0; 6.4) and 3.2 % (1.9; 4.8) in Herd III and to 2.8 % (1.9; 3.8) and 4.9 % (3.6; 6.4) in Herd IV at the next samplings. The estimated prevalence of M. bovis in colostrum ranged between 1.7 % (0.2; 2.8) and 4.7 % (2.7; 7.1) and in clinical mastitis cases between 3.7 % (1.7; 6.4) and 11.0 % (7.5; 15.2) in the study herds. M. bovis strains isolated from cows and calves clustered within herds indicating possible transmission of M. bovis between dairy cows and calves. Prevalence of M. bovis in colostrum and clinical mastitis cases as well as the within-herd prevalence of M. bovis IMI was low in endemically infected dairy herds.


Assuntos
Glândulas Mamárias Animais/microbiologia , Mastite Bovina/epidemiologia , Mastite Bovina/microbiologia , Infecções por Mycoplasma/veterinária , Mycoplasma bovis/genética , Animais , Técnicas de Tipagem Bacteriana , Teorema de Bayes , Bovinos , Colostro/microbiologia , Estudos Transversais , Indústria de Laticínios , Estônia/epidemiologia , Feminino , Genótipo , Tipagem de Sequências Multilocus , Infecções por Mycoplasma/epidemiologia , Mycoplasma bovis/classificação , Prevalência
13.
J Dairy Sci ; 103(4): 3431-3446, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32008788

RESUMO

Staphylococcus aureus is recognized worldwide as one of the main contagious mastitis agents in cattle and can express a set of antimicrobial resistance genes and virulence-associated genes that explain the wide range of outcomes of intramammary infections. Staphylococcus aureus strains are heterogeneous: their different resistance and virulence patterns, associated with host-level factors and treatment factors, are related to the severity of infection. The aim of this study was to determine phenotypic antibiotic susceptibility, occurrence of selected antimicrobial resistance genes and other virulence genes in 93 S. aureus strains isolated from clinical mastitis in 6 countries: Argentina, Brazil, Germany, Italy, the United States (New York State), and South Africa. These isolates were tested against a total of 16 drugs (amoxicillin-clavulanate, ampicillin, cefazolin, cefoperazone, cefquinome, enrofloxacin, erythromycin, gentamicin, kanamycin, lincomycin, oxacillin, penicillin, rifampin, spiramycin, sulfamethoxazole/trimethoprim, tylosin) by minimum inhibitory concentration (MIC) assay, and examined for the presence of 6 antibiotic-resistance genes (blaZ, mecA, mecC, ermA, ermB, ermC) and 6 virulence-associated genes (scn, chp, sak, hla, hlb, sea) via PCR analysis. The phenotypic results of this study revealed the presence of 19.4% penicillin-resistant strains, whereas 22.6% of the strains were classified as having resistance (5.4%) or intermediate resistance (17.2%) to erythromycin. Most (96.8%) of the isolates were inhibited by cephalosporins, and all were susceptible to amoxicillin-clavulanate. Two strains (1 from Germany, 1 from Italy) were resistant to oxacillin and were positive for mecA. Among the other antimicrobial resistance genes, the most frequently detected was blaZ (46.2%), and 32.3% of the isolates were positive for erm genes: ermC (21.5%) and ermB (10.8%). The most prevalent virulence gene was hla (100%), followed by hlb (84.9%) and sea (65.6%). These results show a low prevalence of antibiotic multidrug resistance in S. aureus isolates, even if the detection of selected antimicrobial resistance genes did not always correspond with the occurrence of phenotypic antibiotic resistance; the immune evasion cluster gene prevalence was quite low in the samples analyzed.


Assuntos
Antibacterianos/farmacologia , Farmacorresistência Bacteriana , Mastite Bovina/microbiologia , Infecções Estafilocócicas/veterinária , Staphylococcus aureus/efeitos dos fármacos , Animais , Argentina , Brasil , Bovinos , Farmacorresistência Bacteriana/genética , Eritromicina/farmacologia , Feminino , Alemanha , Itália , Testes de Sensibilidade Microbiana , New York , Oxacilina/farmacologia , África do Sul , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus/isolamento & purificação , Staphylococcus aureus/patogenicidade , Virulência
14.
J Dairy Sci ; 103(4): 3459-3469, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32037172

RESUMO

The purpose of this study was to determine the effect of intramammary pirlimycin on the fecal microbiome of dairy cattle. Primiparous heifers were enrolled and assigned to a treatment or control group at a ratio of 2:1. In part 1 of the study, treated heifers (T1) were given intramammary pirlimycin into one infected quarter once daily for 2 d at 24-h intervals, according to the label instructions. Control heifers received no treatment. In part 2 of the study, treated heifers (T2) were given intramammary pirlimycin into one infected quarter once daily for 8 d at 24-h intervals, according to the label instructions. All enrolled heifers (T1, T2, and control) had quarter-level milk samples aseptically collected for bacterial culture and fecal samples collected for 16S rRNA gene sequencing on d 0, 2, 7, 14, 21, and 28. Milk samples were plated on Columbia blood agar and incubated at 37°C for 24 h. Bacteria were identified using MALDI-TOF mass spectrometry. The DNA was extracted from feces using PowerFecal kits (Qiagen, Venlo, the Netherlands). The 16S rRNA gene amplicon library construction and sequencing was performed at the University of Missouri DNA Core facility. Testing for differences in fecal community composition was performed via one-way permutational multivariate ANOVA of Bray-Curtis and Jaccard similarities using Past 3.13 (https://folk.uio.no/ohammer/past/). Mean total count of operational taxonomic units and Chao1, Shannon, and Simpson α-diversity indices were determined and compared via t-test or Wilcoxon rank sum test. A treatment-dependent effect was present in the observed and predicted richness of feces from cows in the T1 group at d 2 posttreatment. Additionally, intramammary pirlimycin induced a significant change in the composition of the fecal microbiota by d 2 in the treated groups. Based on calculated intra-subject similarities, intramammary pirlimycin was associated with a significant acute change in the fecal microbiota of dairy heifers and that chance reversed when the antimicrobial exposure was brief, but sustained following longer exposure. Overall, intramammary pirlimycin administration affected the fecal microbiome of lactating dairy heifers. Further work is necessary to determine the effect of these changes on the heifer and the dairy environment as well as if treatment is influencing antimicrobial resistance among enteric and environmental bacteria.


Assuntos
Antibacterianos/farmacologia , Bovinos/microbiologia , Clindamicina/análogos & derivados , Fezes/microbiologia , Microbiota/efeitos dos fármacos , Animais , Antibacterianos/administração & dosagem , Bactérias/classificação , Bactérias/efeitos dos fármacos , Bactérias/isolamento & purificação , Clindamicina/administração & dosagem , Clindamicina/farmacologia , Feminino , Lactação , Glândulas Mamárias Animais , Mastite Bovina/microbiologia , Leite , Países Baixos , RNA Ribossômico 16S/análise
15.
J Dairy Sci ; 103(4): 3493-3504, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32037181

RESUMO

Klebsiella pneumoniae, a common cause of clinical mastitis (CM) in dairy cows, can cause severe clinical symptoms. However, its pathogenicity in the bovine mammary gland is not well understood. Our objectives were to establish an in vitro infection model of K. pneumoniae on bovine mammary epithelial cells (bMEC) to assess (1) cytopathogenicity (adhesive and invasive ability, damage and apoptosis, pro-inflammatory effects) of K. pneumoniae on bMEC and (2) the role of hypermucoviscous (HMV) phenotype on cytopathogenicity. Two K. pneumoniae isolates from CM cows, 1 HMV and 1 non-HMV, were used to infect bMEC. Adhesion and invasion ability, release of lactate dehydrogenase (LDH), ultrastructural morphology, apoptosis, transcriptional expression of pro-inflammatory genes and production of pro-inflammatory cytokines were characterized at various intervals. Both K. pneumoniae isolates rapidly adhered to and invaded bMEC within 1 h post infection (pi), causing ultrastructural damage (swelling of mitochondria and vesicle formation on cell surface) after 3 h pi and apoptotic death after 9 h pi. In addition, K. pneumoniae promoted transcriptional expression of pro-inflammatory genes IL-6, IL-8, IL-1ß, and tumor necrosis factor (TNF)-α and production of IL-8, IL-1ß, and TNF-α cytokines. Compared with non-HMV K. pneumoniae, the HMV isolate had lower adhesive and invasive abilities but caused more serious cellular damage. In conclusion, K. pneumoniae was cytopathogenic on bMEC and induced a pro-inflammatory response; however, the HMV phenotype did not have a key role in pathogenicity. Therefore, more attention should be paid to milk loss, and targeted prevention and treatment strategies should be implemented in Klebsiella mastitis episodes.


Assuntos
Células Epiteliais/microbiologia , Klebsiella pneumoniae/patogenicidade , Glândulas Mamárias Animais/microbiologia , Mastite Bovina/microbiologia , Animais , Apoptose , Aderência Bacteriana , Bovinos , Linhagem Celular , Citocinas/metabolismo , Células Epiteliais/metabolismo , Feminino , Interleucinas/metabolismo , Klebsiella pneumoniae/isolamento & purificação , Glândulas Mamárias Animais/patologia , Leite/microbiologia , Mitocôndrias/metabolismo , Fator de Necrose Tumoral alfa/metabolismo
16.
J Dairy Sci ; 103(4): 3479-3492, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32089304

RESUMO

The objective of this study was to describe diversity of Klebsiella pneumoniae isolated from milk collected at detection of nonsevere (abnormal milk or abnormal udder) clinical mastitis (CM) and during a follow-up period. Cases were detected in cows enrolled in a randomized clinical trial (n = 168) conducted using 2 related Wisconsin dairy farms. Cases were randomly assigned to receive 2 d (n = 18) or 8 d (n = 18) of intramammary infusions with an approved product containing ceftiofur hydrochloride or assigned to a negative control group (n = 17). Milk samples were collected from affected quarters at detection and during a 28-d follow-up period. Sufficient DNA was recovered from 53 of 54 Kleb. pneumoniae cultured from quarter milk samples collected at detection of the incident case. Additional Kleb. pneumoniae were recovered from milk samples collected from the same quarters at 14, 21, and 28 d after case detection (n = 35), at detection of recurrent cases in the same quarter (n = 14), and from new cases of CM (n = 3) occurring in enrolled quarters. All Kleb. pneumoniae were used for molecular typing by pulsed-field gel electrophoresis and 90% similarity was used to define homology. Of Kleb. pneumoniae recovered from incident cases, unique strains (n = 41) were identified in milk samples collected from cows on farm A (n = 19) and farm B (n = 22), whereas 12 clonal strains were identified with 8 found only in milk collected from farm A and 4 found in milk samples collected from cows on both farms. Heterogeneous strains of Kleb. pneumoniae genotypes were isolated from incident cases of CM. However, when intramammary infection persisted or when recurrence of CM occurred, clonal strains were isolated at 14, 21, or 28 d. Similar strains of Kleb. pneumoniae genotypes caused persistent CM. In conclusion, initial cases of CM were caused by a wide genetic diversity of Kleb. pneumoniae, but when IMI persisted, the same strain often persisted within the mammary gland up to 28 d.


Assuntos
Infecções por Klebsiella/veterinária , Klebsiella pneumoniae , Mastite Bovina/epidemiologia , Animais , Antibacterianos/uso terapêutico , Bovinos , Cefalosporinas/uso terapêutico , Eletroforese em Gel de Campo Pulsado , Fazendas , Feminino , Mastite Bovina/microbiologia , Leite , Epidemiologia Molecular , Wisconsin/epidemiologia
17.
J Dairy Sci ; 103(4): 3368-3380, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32008777

RESUMO

Staphylococcus aureus is one of the major pathogens causing mastitis in dairy herds. The colonization of dairy cows and subsequent contamination of raw milk by S. aureus, especially strains exhibiting multidrug resistance and biofilm-forming and toxin-producing abilities, remains an important issue for both dairy farmers and public health. In this study, we investigated the prevalence, antimicrobial susceptibility, biofilm formation, and genetic diversity of S. aureus from subclinical bovine mastitis in dairy farms located in southern Xinjiang, China. Sixty-five isolates from 84 subclinical mastitic milk samples were identified as S. aureus. The resistance rates to penicillin, erythromycin, clindamycin, tetracycline, gentamicin, linezolid, rifampicin, quinupudin-dafupudin, ciprofloxacin, norfloxacin, and chloramphenicol were 58.5, 44.6, 40.0, 18.5, 12.3, 10.8, 9.2, 6.2, 4.6, 4.6, and 1.5%, respectively. All isolates were susceptible to cefoxitin, sulfamethoxazole-trimethoprim, and vancomycin. Isolates from farm A showed a significantly higher resistance rate to tetracycline (16.9%) than those from farm B (1.5%). The most frequently detected virulence factors were hla (96.9%, 63/65) and hlb (100.0%, 65/65). The percentage rates of the staphylococcal enterotoxin genes sea, sec, sed, seg, seh, sei, and sej in S. aureus isolates were 4.6, 33.8, 27.7, 3.1, 41.5, 41.5, and 7.7%, respectively. The percentage rate of the sec gene in isolates from farm B (30.8%) was significantly higher than that of farm A (3.1%). The percentage rates of the tsst and pvl genes in S. aureus isolates were 26.2 and 40.0%. The percentage rate of the pvl gene in isolates from farm B (32.3%) was significantly higher than that of farm A (7.7%). The adhesion molecules fnbA, fnbB, clfA, clfB, and cna were detected in 21 (32.3%), 23 (35.4%), 65 (100.0%), 65 (100.0%), and 65 (100.0%) isolates, respectively. The percentage rates of the icaA, sarA, tcaR, ccp, luxS, and sigB genes in S. aureus isolates were 69.2, 100.0, 86.2, 95.4, 84.6, and 100.0%, respectively. The fnbB and icaA genes were more frequently detected in isolates from farm A (29.2 and 40.0%, respectively) than those from farm B (6.2 and 29.2%, respectively). The luxS gene was more often found in isolates from farm B (50.8%) than those from farm A (33.8%). Using the microplate method, 61.5, 26.2, and 10.8% of the isolates showed weak, moderate, and strong biofilm-forming abilities, respectively. Different clonal complex (CC) and spa-types were identified, including CC81, CC398, CC88, CC5405, and CC5406. Importantly, in this study we report for the first time 41 new sequence types (ST) among 44 distinct ST. These results indicated high genetic diversity of S. aureus involved in subclinical bovine mastitis in southern Xinjiang, China. The results also showed that S. aureus from subclinical bovine mastitis cases in southern Xinjiang, China, were mainly resistant to ß-lactams, erythromycin, and clindamycin. Also, biofilm- and adhesion-related genes, which are increasingly known as important virulence factors in the pathogenesis of S. aureus infections, were detected at a high rate. This study could help identify predominant clones and provide surveillance measures to decrease or eliminate S. aureus contamination in raw milk of dairy cows with subclinical mastitis.


Assuntos
Mastite Bovina/epidemiologia , Infecções Estafilocócicas/veterinária , Staphylococcus aureus/isolamento & purificação , Animais , Antibacterianos/farmacologia , Bovinos , China , Enterotoxinas/genética , Feminino , Mastite Bovina/microbiologia , Prevalência , Infecções Estafilocócicas/epidemiologia , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/genética , Fatores de Virulência/genética
18.
BMC Genomics ; 21(1): 102, 2020 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-32000686

RESUMO

BACKGROUND: Neutrophils are the first effectors of inflammatory response triggered by mastitis infection, and are important defense cells against pathogenic Escherichia coli (E. coli). DNA methylation, as a critical epigenetic mechanism for regulating gene function, is involved in bovine mastitis. RESULTS: In this study, we sequenced the blood neutrophils of healthy and E. coli-infected mastitic half-sib cows for the overall DNA methylation levels using transcriptome sequencing and reduced representation bisulfite sequencing. The methylation levels in the mastitis cows (MCs) were decreased compared with healthy cows (HCs). A total of 494 differentially methylated regions were identified, among which 61 were up-methylated and 433 were down-methylated (MCs vs. HCs). The expression levels of 1094 differentially expressed genes were up-regulated, and 245 genes were down-regulated. Twenty-nine genes were found in methylation and transcription data, among which seven genes' promoter methylation levels were negatively correlated with expression levels, and 11 genes were differentially methylated in the exon regions. The bisulfite sequencing PCR and quantitative real-time PCR validation results demonstrated that the promoter methylation of CITED2 and SLC40A1 genes affected differential expression. The methylation of LGR4 exon 5 regulated its own alternative splicing. The promoter methylation of bta-miR-15a has an indirect effect on the expression of its target gene CD163. The CITED2, SLC40A1, and LGR4 genes can be used as candidates for E. coli-induced mastitis resistance. CONCLUSIONS: This study explored the roles of DNA methylation in affecting transcription of protein-coding genes and miRNAs in E. coli-induced mastitis, thereby helping explain the function of DNA methylation in the pathogenesis of mastitis and provided new target genes and epigenetic markers for mastitis resistance breeding in dairy cattle.


Assuntos
Metilação de DNA , Infecções por Escherichia coli/veterinária , Perfilação da Expressão Gênica/veterinária , Mastite Bovina/genética , Neutrófilos/química , Sequenciamento Completo do Genoma/veterinária , Animais , Estudos de Casos e Controles , Bovinos , Epigênese Genética , Infecções por Escherichia coli/genética , Feminino , Regulação da Expressão Gênica , Redes Reguladoras de Genes , Mastite Bovina/microbiologia , MicroRNAs/genética , Regiões Promotoras Genéticas , Análise de Sequência de RNA/veterinária
19.
BMC Vet Res ; 16(1): 33, 2020 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-32005239

RESUMO

BACKGROUND: In dairy herds, mastitis causes detrimental economic losses. Genetic selection offers a sustainable tool to select animals with reduced susceptibility towards postpartum diseases. Studying underlying mechanisms is important to assess the physiological processes that cause differences between selected haplotypes. Therefore, the objective of this study was to establish an in vivo infection model to study the impact of selecting for alternative paternal haplotypes in a particular genomic region on cattle chromosome 18 for mastitis susceptibility under defined conditions in uniparous dairy cows. RESULTS: At the start of pathogen challenge, no significant differences between the favorable (Q) and unfavorable (q) haplotypes were detected. Intramammary infection (IMI) with Staphylococcus aureus 1027 (S. aureus, n = 24, 96 h) or Escherichia coli 1303 (E. coli, n = 12, 24 h) was successfully induced in all uniparous cows. This finding was confirmed by clinical signs of mastitis and repeated recovery of the respective pathogen from milk samples of challenged quarters in each animal. After S. aureus challenge, Q-uniparous cows showed lower somatic cell counts 24 h and 36 h after challenge (P < 0.05), lower bacterial shedding in milk 12 h after challenge (P < 0.01) and a minor decrease in total milk yield 12 h and 24 h after challenge (P < 0.01) compared to q-uniparous cows. CONCLUSION: An in vivo infection model to study the impact of genetic selection for mastitis susceptibility under defined conditions in uniparous dairy cows was successfully established and revealed significant differences between the two genetically selected haplotype groups. This result might explain their differences in susceptibility towards IMI. These clinical findings form the basis for further in-depth molecular analysis to clarify the underlying genetic mechanisms for mastitis resistance.


Assuntos
Mastite Bovina/genética , Mastite Bovina/microbiologia , Herança Paterna , Animais , Bovinos , Indústria de Laticínios , Escherichia coli , Infecções por Escherichia coli/veterinária , Feminino , Haplótipos , Masculino , Leite/microbiologia , Infecções Estafilocócicas/veterinária , Staphylococcus aureus
20.
J Dairy Sci ; 103(4): 3392-3400, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32089315

RESUMO

Klebsiella spp. are important opportunistic pathogens commonly defined as environmental clinical mastitis agents. Despite Klebsiella mastitis being clinically impairing in cows and costly to the industry, only a few studies describe Klebsiella isolated from mastitis cases. The aim of this work was to characterize species of Klebsiella involved in clinical mastitis cases in Canada. Klebsiella isolated from clinical mastitis cases (n = 53) were identified to the species level using a biochemical test panel and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The rpoB gene sequence was used as the gold standard method and identified Klebsiella pneumoniae (n = 40), Klebsiella oxytoca (n = 9), Raoultella ornithinolytica (n = 2), and Raoultella planticola (n = 2). Raoultella, a genus closely related to Klebsiella, was also accurately identified using mass spectrometry but not via biochemical testing. Using the disc diffusion technique, 31 (58%) isolates were found to be susceptible to all antimicrobials tested (n = 18). The remaining 22 (42%) isolates were resistant to 1 or more of the following antimicrobials: kanamycin (2%), streptomycin (38%), spectinomycin (13%), sulfisoxazole (13%), and tetracycline (19%). The following antimicrobial resistance genes were identified: tetA, tetB, sul1, strA/strB, and aadA. Random amplified polymorphic DNA revealed the majority of our isolates as unrelated and having different patterns, indicating environmental contamination as the primary source of infection. All isolates were shown to be biofilm producers. In conclusion, although antimicrobial resistance was low for both Klebsiella and Raoultella species, genetically related Klebsiella spp. isolates appeared to be more resistant.


Assuntos
Klebsiella/isolamento & purificação , Mastite Bovina/microbiologia , Animais , Antibacterianos/farmacologia , Canadá , Bovinos , Farmacorresistência Bacteriana/genética , Feminino , Klebsiella/classificação , Klebsiella/efeitos dos fármacos , Klebsiella/fisiologia , Mastite Bovina/tratamento farmacológico , Testes de Sensibilidade Microbiana
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA