Porcine ear necrosis syndrome by coinfection of porcine reproductive and respiratory syndrome virus and Staphylococcus hyicus

Porcine ear necrosis syndrome is characterized by erosive and ulcerative lesions at the margin or tip of the pinna. Three growing pigs of different ages exhibited retarded growth accompanied by reddening and necrosis of ear prior to death. Gross examination showed reddening, swelling, black discoloration, scaling, and variable-sized yellowish materials and edema in ear cross section. Microscopically, thrombosis, abscess, ulceration, epidermal hyperplasia, and dermal pyogranulomatous inflammation with an intralesional bacterial colony were observed. Staphylococcus hyicus was isolated in all pigs' ears and porcine reproductive and respiratory syndrome virus was detected by PCR and immunohistochemistry.

Detection by multiplex PCR of Staphylococcus aureus , S. intermedius and S. hyicus in artificially contaminated milk / Detecção de Staphylococcus aureus , S. intermedius e S. hyicus em leite contaminado artificialmente por multiplex PCR

ABSTRACT: This research aimed to detect coagulase-positive Staphylococcus (CPS) directly in samples of artificially contaminated milk, using multiplex PCR (mPCR). Standard and isolated bacterial strains of S. aureus, S. epidermidis, S. hyicus, S. intermedius, Listeria monocytogenes and Escherichia coli species were used, evaluating the specificity and detection limit of mPCR, for artificially contaminated UHT milk. Primers specific for the nuc gene (NUC1-NUC2 were used for S. aureus, NUC3-NUC4 for S. hyicus and NUC5-NUC6 for S. intermedius). It was possible to detect the three target species by mPCR, directly from bovine whole milk, with adequate specificity and acceptable detention limit for identification of coagulase-positive Staphylococcus (CPS) in foods. The specificity was determined by the amplification of species-specific fragments, and the detection limit was assessed by the detection thresholds obtained for the three species (103 CFU mL-1). From these results, the mPCR described, with the proposed set of primers, has the potential for use in precise identification and differentiation between CPSs in milk samples.

RESUMO: Esta pesquisa teve como objetivo detectar diretamente em amostras de leite contaminado artificialmente Staphylococcus coagulase positiva (ECP) por multiplex PCR (mPCR). Cepas padrão e isolados de S. aureus, S. epidermidis, S. hyicus, S. intermedius, Listeria monocytogenes e Escherichia coli foram utilizados no estudo. Foram utilizados primers específicos para o gene nuc (NUC1-NUC2 para o S. aureus, NUC3-NUC4 para o S. hyicus e NUC5-NUC6 para o S. intermedius ). Foi possível detectar as três espécies-alvo por mPCR, formar diretamente nas amostras de leite integral bovino, com especificidade adequada e limite de detecção aceitável para identificação de espécies de Staphylococcus coagulase positiva (ECP) em alimentos. A especificidade foi determinada por meio da amplificação de fragmentos específicos das espécies e o limite de detecção foi avaliado pelos limiares de detecção obtidos para as três espécies (103 UFC mL-1 para as espécies presentes nas amostras de leite contaminadas artificialmente).

Distribution of the putative virulence factor encoding gene sheta in Staphylococcus hyicus strains of various origins

In the present study, Staphylococcus (S.) hyicus strains isolated in Russia (n = 23) and Germany (n = 17) were investigated for the prevalence of the previously described genes sheta and shetb. Sheta was detected in 16 S. hyicus strains. Sheta-positive strains were mainly found among strains isolated from exudative epidermitis, and frequently together with the exfoliative toxin-encoding genes exhD and exhC. Partial sequencing of sheta in a single S. hyicus strain revealed an almost complete match with the sheta sequence obtained from GenBank. None of the S. hyicus strains displayed a positive reaction with the shetb-specific oligonucleotide primer used in the present study. According to the present results, the exotoxin encoding gene sheta seems to be distributed among S. hyicus strains in Russia and Germany. The toxigenic potential of this exotoxin, which does not have the classical structure of a staphylococcal exfoliative toxin, remains to be elucidated.

Staphylococcus isolados a partir do leite bovino in natura / Staphylococcus hyicus subsp. chromogenes isolated from bovine milk in natura

Staphylococcus hyicus subsp chromogenes foi isolado a partir do leite bovino coletado em 5 dos 40 animais estudados. Este resultado corresponde a uma incidência de 12,5 por cento. As amostras foram testadas quanto a capacidade de produção de enterotoxinas, porém mostraram-se negativas. Foi também verificada a sensibilidade das amostras a agentes antimicrobianos. Todas foram sensíveis à ampicilina, cefalotina, eritromicina, gentamicina, lincomicina, penicilina, tetraciclina e tobramicina. Apenas um foi resistente ao cloranfenicol e uma outra à estreptomicina.