Occurrence of Clinical and Sub-Clinical Mastitis in Dairy Herds in the West Littoral Region in Uruguay

Twenty-nine dairy farms were selected to determine the incidence of clinical mastitis, prevalence of sub-clinical mastitis and bacterial aetiology in the West Littoral Region of Uruguay. In samples taken by the owner and frozen at -20°C during a week the incidence rate of clinical mastitis was determined as 1.2 cases per 100 cow-months at risk. Staphylococcus aureus was the most common isolated pathogen in 37.5% of 40 milk samples from clinical cases obtained in 1 month. No bacteria grew in the 32.5% of the total samples. A sub-sample including 1077 dairy cows from randomly selected farms was used to determine the prevalence of sub-clinical mastitis. These samples were taken on one visit to each farm. The prevalence was 52.4% on a cow basis and 26.7% on an udder quarter basis. In 55.1% of the quarters of the selected animals with more than 300 000 cells/ml there was no growth. The isolated pathogens from sub-clinical cases and their relative frequencies were: Staphylococcus aureus 62.8%, Streptococcus agalactiae 11.3%, Enterococcus sp. 8%, coagulase-negative staphylococci 7.4%, Streptococus uberis 6.4%, Streptococcus dysgalactiae 1.8%, Escherichia coli 1.5% and Staphylococcus hyicus coagulase-positive 0.6%

Detección de Listeria monocytogenes en un rodeo de bovinos de carne en el que previamente ocurrió un caso clínico de listeriosis nerviosa

Listeriosis es una enfermedad asociada al consumo de alimentos contaminados con bacterias del género Listeria. Este trabajo se realizó en un sistema de cría extensiva de bovinos. Los objetivos fueron confirmar la sospecha clínica de un caso de listeriosis nerviosa en un bovino de carne a pastoreo, detectar la presencia de portadores asintomáticos de Listeria sp. en el rodeo y establecer la presencia de bacterias del genero Listeria en pasturas y agua de bebida del predio. Se realizó la necropsia de una vaca de cría que presentaba marcha en círculos, decúbito y muerte. En sistema nervioso central (SNC) se recuperaron colonias de Listeria monocytogenes, mientras que en la histopatología se observó meningoencefalitis supurativa con múltiples microabscesos en tronco encefálico e inmunomarcación positiva a L. monocytogenes. Se detectaron dos vacas de cría portadoras asintomáticas que excretaban L. monocytogenes y seis que excretaban L. innocua en materia fecal. En las muestras de pasturas no hubo aislamiento, mientras que en la muestra de agua de arroyo se recuperó L. innocua. El aislamiento de L. monocytogenes obtenido de SNC y otro de una vaca portadora asintomática se tipificaron como perfil de serotipo 4b, el restante se tipifico como perfil 1/2a. Estos serotipos coinciden con los más comúnmente reportados a nivel mundial en casos humanos y animales, así como en alimentos para consumo humano a nivel nacional. Es necesario continuar los estudios epidemiológicos en los sistemas de producción cárnica y lechera de Uruguay para conocer la dispersión del agente, establecer su relación con casos de listeriosis en humanos y diseñar/aplicar medidas de control adecuadas que disminuyan su diseminación entre animales de producción

Etiology and antimicrobial susceptibility of udder pathogens from cases of subclinical mastitis in dairy cows in Sweden

<p>Abstract</p> <p>Background</p> <p>A nationwide survey on the microbial etiology of cases of subclinical mastitis in dairy cows was carried out on dairy farms in Sweden. The aim was to investigate the microbial panorama and the occurrence of antimicrobial resistance. Moreover, differences between newly infected cows and chronically infected cows were investigated.</p> <p>Methods</p> <p>In total, 583 quarter milk samples were collected from 583 dairy cows at 226 dairy farms from February 2008 to February 2009. The quarter milk samples were bacteriological investigated and scored using the California Mastitis Test. Staphylococci were tested for betalactamase production and presence of resistance was evaluated in all specific udder pathogens. Differences between newly infected cows and chronically infected cows were statistically investigated using logistic regression analysis.</p> <p>Results</p> <p>The most common isolates of 590 bacteriological diagnoses were <it>Staphylococcus (S) aureus </it>(19%) and coagulase-negative staphylococci (CNS; 16%) followed by <it>Streptococcus (Str) dysgalactiae </it>(9%), <it>Str. uberis </it>(8%), <it>Escherichia (E.) coli </it>(2.9%), and <it>Streptococcus </it>spp. (1.9%). Samples with no growth or contamination constituted 22% and 18% of the diagnoses, respectively. The distribution of the most commonly isolated bacteria considering only bacteriological positive samples were: <it>S. aureus </it>- 31%, CNS - 27%, <it>Str. dysgalactiae </it>- 15%, <it>Str. uberis </it>- 14%, <it>E. coli </it>- 4.8%, and <it>Streptococcus </it>spp. - 3.1%. There was an increased risk of finding <it>S. aureus, Str. uberis </it>or <it>Str. dysgalactiae </it>in milk samples from chronically infected cows compared to findings in milk samples from newly infected cows. Four percent of the <it>S. aureus </it>isolates and 35% of the CNS isolates were resistant to penicillin G. Overall, resistance to other antimicrobials than penicillin G was uncommon.</p> <p>Conclusions</p> <p><it>Staphylococcus aureus </it>and CNS were the most frequently isolated pathogens and resistance to antimicrobials was rare.</p

A Highly Pathogenic Strain of Staphylococcus sciuri Caused Fatal Exudative Epidermitis in Piglets

Staphylococcus sciuri are important human pathogens responsible for endocarditis, peritonitis, septic shock, urinary tract infection, pelvic inflammatory disease and wound infections. However, little information is known regarding the pathogenicity of S. sciuri to animals. From the pericardial fluid of a diseased piglet with exudative epidermitis (EE), we isolated a strain of Staphylococcus in pure culture. Surprisingly, this isolate was a member of S. sciuri rather than S. hyicus as identified by its biochemical traits and also by analysis of 23S ribosomal DNA using Internal Transcribed Spacer PCR. In addition, inoculation of newborn piglets with 1×10(10) CFU of the isolate by oral feeding or intra-muscular injection successfully reproduced EE in piglets, which suggested that the oral intake of the pathogen by the animals is one of the major routes of exposure. These unexpected findings prioritized S. sciuri as important zoonotic agents, which may have ramifications for human medicine

Changing trends in mastitis

<p>Abstract</p> <p>The global dairy industry, the predominant pathogens causing mastitis, our understanding of mastitis pathogens and the host response to intramammary infection are changing rapidly. This paper aims to discuss changes in each of these aspects. Globalisation, energy demands, human population growth and climate change all affect the dairy industry. In many western countries, control programs for contagious mastitis have been in place for decades, resulting in a decrease in occurrence of <it>Streptococcus agalactiae </it>and <it>Staphylococcus aureus </it>mastitis and an increase in the relative impact of <it>Streptococcus uberis </it>and <it>Escherichia coli </it>mastitis. In some countries, <it>Klebsiella </it>spp. or <it>Streptococcus dysgalactiae </it>are appearing as important causes of mastitis. Differences between countries in legislation, veterinary and laboratory services and farmers' management practices affect the distribution and impact of mastitis pathogens. For pathogens that have traditionally been categorised as contagious, strain adaptation to human and bovine hosts has been recognised. For pathogens that are often categorised as environmental, strains causing transient and chronic infections are distinguished. The genetic basis underlying host adaptation and mechanisms of infection is being unravelled. Genomic information on pathogens and their hosts and improved knowledge of the host's innate and acquired immune responses to intramammary infections provide opportunities to expand our understanding of bovine mastitis. These developments will undoubtedly contribute to novel approaches to mastitis diagnostics and control.</p

Fotosensibilización hepatógena en bovinos provocada por fasciolasis crónica. [Bovine hepatogenic photosensitization caused by chronic fasciolasis.]

RESUMEN.- La fotosensibilización hepatógena en bovinos puede ser provocada por diversas causas, entre ellas, como consecuencia del daño que provoca Fasciola hepatica a nivel hepatocelular. La fotodermatitis de origen hepatógeno es uno de los signos clínicos que se puede observar en cuadros de fasciolasis crónica, debido en su capacidad de producir fibrosis hepática y colangitis con estasis biliar. El objetivo de este trabajo fue describir dos brotes de fotosensibilización hepatógena en bovinos en los departamentos de Tacuarembó y Soriano (Uruguay). La enfermedadafectó a un lote de vacas Hereford y cruza, y a un lote de vaquillonas cruzas. En ambos brotes los animales pastoreaban en campos forestales húmedos. Los principales signos clínicos observados fueron pérdida de peso, costras y peladuras en morro, fotofobia, sialorrea y corrimientos oculares. Se realizaron necropsias visualizando como hallazgos macroscópicos relevantes dermatitis necrótica bilateral de los párpados, úlceras en cara ventral de lengua. En hígado se observó engrosamiento de la cápsula de Glisson, fibrosis difusa y colangitis crónica con calcificación de los canalículos biliares. Al examen histopatológico se destacó como principal lesión, fibrosis hepática y obstrucción canalicular con presencia de Fasciola hepatica. En base a los signos clínicos, hallazgos macro y microscópicos, la fotosensibilización observada en los animales de ambos brotes estuvodirectamente relacionada con las alteraciones hepáticas crónicas causadas por F. hepatica. ----------------- SUMMARY.- Bovine hepatogenic photosensitization can be caused by several causes, such as hepatocellular damage due to by Fasciola hepatica. Hepatogenic photodermatitis is one of the clinical signs that can be observed in chronic fasciolasis, caused by hepatic fibrosis and cholangitis with bile stasis. The objective of thiswork was to describe two outbreaks of hepathogenic photosensitization in cattle in the counties of Tacuarembó and Soriano (Uruguay). The disease affected a herd of Hereford and crossbreed cows and a herd of crossbreed heifers. In both outbreaks the animals grazed in damp forest fields. The main clinical signs observed were weight loss, scabs and peeling on the snout, photophobia, hypersalivation and ocular bleeding. In all necropsiesperformed, the relevant macroscopic findings were bilateral necrotic dermatitis of the eyelids, ulcers on the ventral surface of the tongue. In the liver, there was thickening of the Glisson's capsule, diffuse fibrosis, and chronic cholangitis with calcification of the bile canaliculi. Histopathologically the main lesion was liver fibrosis and canalicular obstruction with the presence of F. hepatica. Based on the clinical signs, macro and microscopicfindings, the photosensitization observed in the animals of both outbreaks was directly related to the chronic liver alterations caused by F. hepatica

Occurrence of clinical and sub-clinical mastitis in dairy herds in the west littoral region in Uruguay.

ABSTRACT.Twenty-nine dairy farms were selected to determine the incidence of clinical mastitis, prevalence of sub-clinical mastitis and bacterial aetiology in the West Littoral Region of Uruguay. In samples taken by the owner and frozen at -20°C during a week the incidence rate of clinical mastitis was determined as 1.2 cases per 100 cow-months at risk. Staphylococcus aureus was the most common isolated pathogen in 37.5% of 40 milk samples from clinical cases obtained in 1 month. No bacteria grew in the 32.5% of the total samples. A sub-sample including 1077 dairy cows from randomly selected farms was used to determine the prevalence of sub-clinical mastitis. These samples were taken on one visit to each farm. The prevalence was 52.4% on a cow basis and 26.7% on an udder quarter basis. In 55.1% of the quarters of the selected animals with more than 300 000 cells/ml there was no growth. The isolated pathogens from sub-clinical cases and their relative frequencies were: Staphylococcus aureus 62.8%, Streptococcus agalactiae 11.3%, Enterococcus sp, 8%, coagulase-negative staphylococci 7.4%, Streptococus uberis 6.4%, Streptococcus dysgalactiae 1.8%, Escherichia coli 1.5% and Staphylococcus hyicus coagulase-positive 0.6%