Virulence markers associated with Trueperella pyogenes infections in livestock and companion animals.

Trueperella pyogenes is an opportunistic pathogen that causes diverse pyogenic infections in livestock. The genes that encode the exotoxin pyolysin (plo) and other putative factors that promote adhesion of pathogen to host cells (fimbriae fimA, fimC, fimE, fimG, neuraminidases nanH, nanP, and collagen-binding protein cbpA) have been associated with virulence, particularly in mastitis and uterus infections of dairy cows. However, the role of these virulence markers in the pathogenicity of the agent in domestic animals infections still is incompletely understood. The genes plo, fimA, fimC, fimE, fimG, nanH, nanP, and cbpA were investigated in 71 T. pyogenes strains recovered from cattle, sheep, goats, dogs, equines, and a pig, recovered from mastitis (n = 35), and non-mastitis (n = 36) cases (abscesses, reproductive tract diseases, pneumonia, lymphadenitis, encephalitis). The most common genes harboured by the isolates were: plo (71/71 = 100·0%), fimA (70/71 = 98·6%), nanP (56/71 = 78·9%), fimE (53/71 = 74·6%), fimC (46/71 = 64·8%) and nanH (45/71 = 63·4%), whereas cbpA (6/71 = 8·4%) and fimG (4/71 = 5·6%) were uncommon. The most frequent genotypes were plo/fimA/fimE/fimC/nanH/nanP (17/71 = 23·9%), plo/fimA/fimE/nanH/nanP (13/71 = 18·3%), and plo/fimA/fimE/fimC/nanP (11/71 = 15·5%). No association was observed between the presence of genes vs clinical signs or host species. To the best of our knowledge, this is the first report on aforementioned virulence factors of pathogen detected in diseased horses and dogs. SIGNIFICANCE AND IMPACT OF THE STUDY: The role of particular virulence factors of Trueperella pyogenes that determine different pyogenic infections among domestic animals is poorly understood. Eight putative virulence genes and genotype profiles of 71 isolates were investigated among different clinical manifestations in domestic animals. The most common genes were plo (71/71 = 100·0%), fimA (70/71 = 98·6%), nanP (56/71 = 78·9%), fimE (53/71 = 74·6%), fimC (46/71 = 64·8%) and nanH (45/71 = 63·4%), whereas plo/fimA/fimE/fimC/nanH/nanP (17/71 = 23·9%), plo/fimA/fimE/nanH/nanP (13/71 = 18·3%), and plo/fimA/fimE/fimC/nanP (11/71 = 15·5%) were the most frequent genotypes. Studies involving virulence factors are critical in the investigation of molecular epidemiology, pathogenicity, and hypothetical differences in the virulence among T. pyogenes strains from different geographical areas.

Molecular characterization of Polish Prototheca zopfii mastitis isolates and first isolation of Prototheca blaschkeae in Poland.

Bovine mastitits caused by the colorless, yeast-like alga Prototheca zopfii is a serious and complex condition that results in heavy economic losses in the dairy industry, both through a substantial reduction in milk production and culling of infected animals. Based on the 18S rDNA sequence analysis, genotype-specific PCR assays have recently been developed to differentiate within the species P. zopfii three distinct P. zopfii genotypes (1-3), of which P. zopfii genotype 3 has been considered a new species P. blaschkeae sp. nov. The purpose of this study was to employ the newly-devised molecular approach for the detection of the two P. zopfii genotypes and P. blaschkeae sp. nov. among bovine mastitis isolates from Poland. This study is the first to provide molecular characterization of Polish P. zopfii mastitis isolates. It also gives the first description of bovine mammary protothecosis due to P. blaschkeae in Poland, as evidenced by genotypical, microbiological, and electron microscopy findings.

Etiological agents of dairy cows' mastitis in western part of Poland.

The purpose of the study was to determine the etiological mastitis agents in cows from herds located in the western part of Poland in years 2003-2005. Bacteriological examinations of 18,713 samples taken from California Mastitis Test (CMT) positive quarters were performed according to standard methods. Some Gram-negative bacilli and Gram-positive cocci were examined with the use of API tests (Analytical Profile Index). It was found that 32.7% of samples that were CMT positive were culture negative and 9.3% of samples were contaminated. Streptococcus species (15.7%), coagulase negative staphylococci (CNS) (14.6%), Staph. aureus (8.6%), Gram-negative bacilli (4.0%) and Corynebacterium species (3.8%) were most frequently isolated. Escherichia coli (52.3%) dominated among Gram-negative bacilli followed by Klebsiella pneumoniae (4.1%), Pseudomonas aeruginosa (3.6%), Enterobacter cloacae (3.6%), Serratia marcescens (3.1%), Pasteurella multocida (3.1%), Acinetobacter lwofii (3.1%), and 26 other bacteria species. Stahylococcus xylosus (31.5%), Staph. hyicus (12.2%), Staph. haemolyticus (12.2%), Staph. sciuri (11.6%), Staph. chromogenes (8.8%), Staph. epidermidis (8.3%) and Staph. simulans (6.1%) were the most frequent CNS. Streptococcus uberis (50%), Str. dysgalactiae (19.7%), Str. acidominimus (6.6%) and Enterococcus faecalis (5.3%) were mostly found among CAMP-negative streptococci. An increase in frequency of mastitis caused by non-agalactiae streptococci, Staph. aureus, A. pyogenes and yeast-like fungi and a decrease in that produced by Str. agalactiae in 2005 as compared to years 2003 or 2004 were observed.

Isolation of nuc mutant isolates of Staphylococcus aureus from bovine clinical mastitis.

Isolates of Staphylococcus aureus with a mutation in the nuclease (nuc) gene were recovered from cases of bovine mastitis in Poland. Three S. aureus isolates from cows in one herd had a 42 base pair duplication in the nuc gene. These isolates belonged to sequence type 97 (ST97) and clonal complex 97 (CC97). They had a different spa type and multiple-locus variable-number tandem-repeat fingerprinting (MLVF) subtype than a S. aureus isolate without the nuc mutation from the same herd. Isolation of nuc mutant S. aureus strains from cases of bovine mastitis may confound diagnostic PCRs based on detection of the nuc gene.