RESUMEN
Several direct or indirect methods can be used to assess immunoglobulin G (IgG) concentrations in calves, which evaluates the transfer of passive immunity (TPI). Radial immunodiffusion (RID) is the gold standard method to measure serum IgG in bovines. Previous studies have shown that colostrum provides several molecules in addition to immunoglobulins, which play an important role in the passive immunity of the calf. However, no studies have yet determined the level of interference of these components in the immunity, health and survival of calves. In this sense, the objective of this study is to review the methods of evaluation available for the laboratory and field diagnosis of TPI in calves and discuss the main aspects of each technique. Several methods available for TPI evaluation in calves may provide insights into the various components of colostrum involved in passive immunity.
RESUMEN
ABSTRACT: The present study aimed to describe and characterize a nosocomial outbreak caused by a multidrug resistant Salmonella Typhimurium in hospitalized calves at a veterinary medical teaching hospital from Brazil. Sixty-three (96.9%) calves showed lethargy, hyperthermia and profuse diarrhea and despite treatment, 26 (41.2%) animals died. Five animals were necropsied and stool samples of six calves were collected. The isolated strains were subjected to antimicrobial susceptibility test by disc-difusion method and were fingerprinted by ERIC-PCR. Macroscopic lesions suggestive of salmonellosis, such as fibrinonecrotic enteritis and hepatosplenomegaly were observed. Salmonellosis was confirmed by isolation of S. Typhimurium from stool samples and organs from seven affected animals. Six out of seven isolates of S. Typhimurium, exhibited 100% of similarity at ERIC-PCR, suggesting occurrence of nosocomial transmission of S. Typhimurium among the hospitalized calves. All but one S. Typhimurium isolated were resistant to marbofloxacin, enrofloxacin, florfenicol, oxytetracycline and trimethoprim/sulfamethoxazole, antimicrobial agents largely used for humans and animal treatment. This is the first study of a nosocomial outbreak of multidrug resistant S. Typhimurium in a veterinary hospital in Brazil and highlighted the need for preventive measures to reduce the risks for inpatients and humans in contact with animals.
RESUMO: O objetivo do presente estudo é descrever e caracterizar um surto nosocomial provocado por S. Typhimurium multirresistente em bezerros hospitalizados em um hospital escola de medicina veteriária localizado no Brasil. Sessenta e três (96,9%) bezerros apresentaram letargia, hipertermia e diarreia profusa e, apesar do tratamento, vinte e seis animais (41,2%) morreram. Cinco animais foram necropsiados e amostras fecais de seis bezerros foram coletadas. As estirpes isoladas foram submetidas a testes de susceptibilidade a antimicrobianos pelo método de disco-difusão e foram genotipadas pelo ERIC-PCR. Lesões macroscópicas sugestivas de salmonelose, como enterite fibrinonecrótica e hepatoesplenomegalia, foram observadas. Salmonelose foi confirmada pelo isolamento de S. Typhimurium em amostras fecais e órgãos de sete animais. Dos sete isolados, seis apresentaram 100% de similaridade ao ERIC-PCR, sugerindo ocorrẽncia de transmissão nosocomial de S. Typhimurium entre os bezerros hospitalizados. Com excessão de uma estirpe, todas foram resistentes a marbofloxacina, enrofloxacina, florfenicol, oxitetraciclina e trimetoprima/sulfametoxazol, agentes antimicrobianos amplamente utilizados para o tratamento humano e animal. Esse é o primeiro estudo que demonstra um surto nosocomial de estirpes de S. Typhimurium resistentes a múltiplas drogas em um hospital veterinário no Brasil, enfatizando a necessidade de medidas preventivas que reduzam os riscos aos animais hospitalizados e a pessoas que entrarem em contato com esses animais.
