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  • Author: Branko Velebit x
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Characteristics of coagulase positive staphylococci isolated from milk in cases of subclinical mastitis

Abstract

Coagulase-positive staphylococci are the most common pathogen causing subclinical mastitis in cows. Their main characteristic is a high virulence which leads to chronic infection. A total of 213 isolates of coagulase-positive staphylococci were tested. The majority of isolates (58%) formed a gold pigment, then light gold (28%), white gold (8%), golden gray, creamy white and white (2%). The majority of isolated coagulase-positive staphylococci produce beta hemolysis on esculin blood agar (50%), alpha and beta hemolysis (36%), beta and delta hemolysis (8%), delta hemolysis (4%), and alpha hemolysis (2%). Biochemical and molecular identification was performed by APISTAPH and multiplex PCR method. The majority of isolates were identified as S. aureus (88%), S. chromogenes (4%), and 2% of the isolates were identified as S. lentus, S. sciuri, S. xylosus, S. intermedius by APISTAPH. Antimicrobial susceptibility to penicillin G, was found by the Kirby Bauer disk diffusion method to be resistant (62.44%). For disc diffusion penicillin G sensitive isolates the minimal inhibitory concentration (MIC) was established for MIC50 and MIC90 as 0.003 mg/ml and 2μg/ml, respectively. For disc diffusion penicillin G resistant isolates MIC50 and MIC90 was 1.0μg/ml and 16μg/ ml, respectively. The study of phenotypic resistance to methicillin, as recommended by CLSI, established resistance to oxacillin in 5.26% of the isolates, while no resistance was found to cefoxitine. None of the tested isolates have the mecA gene.

Open access
Determination of the Economic Effects in Intesive Production of Piglets

Abstract

Critical indicators of intensive production in hog raising are continuity of production, high level of produced series-tours, application of the most contemporary technological achievements without any turnover of capital, high merchandise turnover, and intensive usage of the reproduction potential of breeding material. Production of piglets represents one of the most essential phases in the production of pork meat. In spite of genetic factors, duration of interval wean-conception is one of the basic factors in determination of bringing forth indexes and number of piglets per litter. In order to recognize production costs of piglets completely we found nutrition costs for piglets and sows represent 61%, while other costs such as personal incomes, veterinary services, water, energy, losses, and amortization represent 39% of total costs. On the basis of cost price per feeding day of a sow and the number of piglets per litter, production costs of piglets older than 28 days with an average body weight of 7 kg were determined. Price cost per piglet after weaning, with 7 kg average body weight, and 146 days of reproduction process accounts for 21,78 EUR if there are 10 piglets in a litter. If the reproductive cycle would last exactly the same and if successful conception would be achieved 25 days after weaning, production cost per piglet would be 23,79 EUR.

Open access
Prevalence and Molecular Characterization of Enterotoxin-Producing Strains of Staphylococcus Aureus Isolated from Serbian Dairy Cows

Abstract

Staphylococcus aureus is known worldwide as a frequent cause of mastitis in dairy cattle. Due to the production of heath resistant enterotoxins, this pathogen is also a major cause of food poisoning among humans, with symptoms of often severe vomiting and diarrhea. The aim of our study was to determine the prevalence of enterotoxinproducing strains of S. aureus originating from samples of cows with subclinical and clinical mastitis in the Republic of Serbia. Furthermore, we analyzed the type of staphylococcal enterotoxin they produce and phylogenetic relatedness among the S. aureus isolates recovered from milk in this study. Production of staphylococcal enterotoxins A, B, C, D and E was determined by commercial immunoenzyme assay VIDAS® SET2, and presence of corresponding genes encoding enterotoxin synthesis in positive isolates confi rmed by Polymerase Chain Reaction. Enterotoxin production was determined in 5 out of 75 (6.67%) isolates of S. aureus and all of them produced staphylococcal enterotoxins C. After analyzing the nucleotide sequence of the gene encoding the synthesis of staphylococcal protein A, S. aureus isolates were assigned into 2 phylogenetic groups, including 7 clusters. All S. aureus isolates with the presence of sec gene formed one cluster even dough they originated from milk samples from different farms.

Open access