Bovin Mastitislerde Staphylococcus aureus’un Rutin Tespitinde Üç Metodun Karşılaştırılması (original) (raw)
Related papers
Brazilian Journal of Microbiology, 2001
Contamination of fresh milk with Staphylococcus aureus was assessed comparatively through routine phenotypic (coagulase tube test and coagulase slide test) and genotypic (PCR) screening of 128 S. aureus strains isolated from 555 milk samples. These samples were collected from 362 cows with subclinical mastitis, hosted in different dairy herds at various locations of the Northern and Northeastern rural areas of the State of Rio de Janeiro, 39.7% of which were CMT-positive. All S. aureus isolates tested positive for the presence of the coagulase gene by PCR and the isolates could be grouped into four distinct classes according to the size of the PCR product. The strains also yielded variable results when assayed with coagulase test. Taken together, these data indicate the existence of extensive polymorphism at the coagulase gene locus in the genus Staphylococcus and exemplifies the extent of molecular and phenotypic heterogeneity associated with the strains circulating in rural herds.
Background: Staphylococcus aureus is one of the most important contagious bacteria causing subclinical bovine mastitis. This bacterial infection is commonly identified by determine the pathogen in bovine milk samples through conventional technique including coagulase test. However, this test has several disadvantages as low sensitivity, risk of biohazard, cost expensive, and limited preparation especially in local area.
Acta Microbiologica et Immunologica Hungarica, 2011
Staphylococcus aureus is considered one of the most important food borne pathogens.A total of 111 isolates of S. aureus were cultured from raw milk samples during January 2009 to June 2009 from Tehran and Mashhad. The coagulase gene polymorphism and the prevalence of classical enterotoxin genes of S. aureus strains were determined by PCR-RFLP (restriction fragment length polymorphism) and Multiplex-PCR. Disk diffusion method was used to determine the susceptibility of isolates to antimicrobial agents as instructed by Clinical and Laboratory Standards Institute.Sixty-seven % of the isolates harboured one or more enterotoxin genes. The most prevalent gene was sec, found in 59 % of the isolates. Approximately 8% of the isolates were positive for sea, seb and sed genes. Only one isolate had see gene. The rate of coexistence of enterotoxin genes was 14%. All S. aureus isolates were susceptible to ciprofloxacin, gentamicin, imipenem, minocycline, oxacillin and vancomycin. They were resist...
Acta Scientiarum. Biological Sciences, 2010
Evaluation of a simplified key for the identification of coagulase-positive Staphylococcus isolated from bovine mastitis. Three hundred fourty four strains of coagulasepositive Staphylococcus (CPS), isolated from mastitis cases, underwent phenotypic and genotypic tests to evaluate the efficiency of a simplified key, based on phenotypic tests for the discrimination of these microorganisms. The tests consisted of amplification of the femA gene and hemolysis in blood agar, production of acetoin and fermentation of maltose, mannitol and trehalose. Strains that showed negative results in the amplification test of the femA gene or that were not identified as Staphylococcus aureus (S. aureus) by phenotypic tests were tested with the APISTAPH kit (Biomériux-France), for precise identification of species. Phenotypic tests revealed 338 strains (98.25%) as S. aureus, three strains (0.86%) as Staphylococcus hyicus, and three microorganisms (0.86%) as Staphylococcus intermedius. PCR demonstrated that 338 (98.25%) strains belonged to the S. aureus species, confirming the results for 336 strains from 338 identified, through a simplified phenotypic key. A high rate of correlation (98.83%) was verifeid between the results of genotypic and phenotypic tests for the identification of S. aureus, demonstrating the applicability of the proposed key, for the discrimination of this microorganism in CPS isolated from bovine mastitis.
Journal of Medical Microbiology, 2013
Rapid isolation and identification of pathogens is a major goal of diagnostic microbiology. In order to isolate and identify Staphylococcus aureus, a number of authors have used a variety of selective and/or differential culture media. However, to date, there are no reports comparing the efficacy of selective and differential culture media for S. aureus isolation from bovine mastitis cases using the 16S rRNA (rrs) gene sequence as a gold standard test. In the present study, we evaluated the efficacy of four selective and/or differential culture media for the isolation of S. aureus from milk samples collected from cows suffering from bovine mastitis. Four hundred and forty isolates were obtained using salt-mannitol agar (SMA, Bioxon), Staphylococcus-110 agar (S110, Bioxon), CHROMAgar Staph aureus (CSA, BD-BBL) and sheep's blood agar (SBA, BD-BBL). All bacterial isolates were identified by their typical colony morphology in the respective media, by secondary tests (for coagulase and b-haemolysis) and by partial 16S rRNA (rrs) gene sequencing as a gold standard test. Sensitivity, positive predictive and negative predictive values were higher for
Iranian Journal of Veterinary Medicine, 2007
To compare PCR and bacterial culture methods for diagnosis of subclinical mastitis caused by Staphylococcus aureus, 100 milk samples from cattle with subclinical mastitis and 20 samples from healthy cattle were collected and tested. The samples were cultured on selective blood agar and bacteria were identified by standard methods. DNA extracted from samples was subjected to PCR reaction with species specific primers and PCR products were analyzed by agarose gel electrophoresis. Based on the PCR results the prevalence of subclinical mastitis due to S. aureus was 25%. In the bacteriological culture of single milk sampling, S. aureus was isolated from the same samples being positive in PCR. A correlation of 100% was found between PCR and single milk sampling culture method by Mc Nemar test. All of the CMT negative samples were also negative in culture and PCR methods. The results of this study indicate that the PCR reaction is sensitive and specific for diagnosis of S. aureus in subcli...
Archivos de medicina veterinaria, 2014
The aim of this work was to identify and to characterise Staphylococcus aureus isolates associated with subclinical mastitis obtained from milk of lactating cows showing a California Mastitis Test (CMT) score result of traces, 1, 2 or 3. Coagulase, hemolysis, presence of capsule, slime formation, biofilm production, autoaggregation, hemagglutination and antibiotic susceptibility were assessed to evaluate S. aureus virulence factors expression potentially associated to bovine subclinical mastitis isolates. Prevalence of subclinical mastitis along the study was low and did not correlate with months or climatic variables. Most of S. aureus (20) were isolated from milk samples showing a CMT score result of 1. Formation of capsule, slime, biofilms and the occurrence of bacteria aggregation in all the tested isolates converged in the bacterial ability of adherence and persistence in the mammary gland and probably contribute to the further chronicity of the infection and even the colonization of dairy installations. Resistance against a set of commonly used antibiotics was low. The evaluation of virulence factors of S. aureus isolates in the context of subclinical mastitis in dairy farms may be useful to develop precise actions and treatments to control mastitis and to improve animal health and milk production in dairy bovine herds.
Al-Anbar Journal of Veterinary Sciences, 2024
This present investigation was done for the Isolation and Molecular confirmation of Staphylococcus aureus from Bovine mastitis-infected cows in various Tamil Nadu, India locations. Two hundred milk samples, ranging from 15 to 20 ml, were collected aseptically from cows in farms in and around Tamil Nadu and surrounding areas after discarding the first few streaks of milk from 2021 to 2023. We used the CMT test to check the milk samples. Following a thorough mixing of the milk samples delivered to the laboratory, one loop containing the infected milk sample was plated on Nutrient agar and incubated at 37 ˚C for 18 to 24 hours. To identify the Staphylococcus aureus, the isolated bacterial colonies were preliminarily identified by Microscopic examination (Gram staining and Motility test), Plating in Selective medium (Mannitol Salt Agar) and Biochemical tests. The DNA of the bacteria was extracted and Polymerase Chain Reaction (PCR) was done to detect the presence of the nuc gene. Of the 200 milk samples obtained from nursing cows, 37.5 % were from Mastitis positive animals; of these, 61.3 % were in the sub-clinical stage, while 38.7 % were in the clinical stage. Only 33 (16.5 %) of the 200 milk samples tested positive for Staphylococcus aureus. A total of 26 out of 75 animals (34.7 %) with Mastitis, and 7 out of 125 animals (5.6 %) without Mastitis. Fifteen (57.7 %) of the twenty-six Staphylococcus aureus isolates found in cows with mastitis were from clinical cases, whereas eleven (42.3%) were from subclinical cases. All of the Staphylococcus aureus isolates examined contained the 279 bp nuc gene, according to the conventional PCR findings. In conclusion, the research has shown that sub-clinical mastitis is more common than clinical mastitis, and that Staphylococcus aureus was substantially more often isolated from mastitis milk, particularly in clinical instances.
Molecular subtyping of Staphylococcus aureus isolates from cases of bovine mastitis in Brazil
Veterinary Microbiology, 1999
Sixty-six isolates of Staphylococcusaureus obtained from milk samples of dairy cows suffering from subclinical mastitis in southern Brazil were analysed by five different molecular typing methods. These included the analysis of plasmid profiles, the analysis of coagulase (coa) gene polymorphisms by PCR amplification of the 3′ terminal region of the coa gene, the PCR-based detection of polymorphisms in the X region of the protein A gene (spa), the PCR-directed analysis of variations in the spacer region between 16S and 23S rRNA, and the comparison of pulsed-field gel electrophoretically separated genomic SmaI fragment patterns. The molecular typing methods were supplemented with the biochemical characterization of the isolates and the determination of their in-vitro susceptibility to 14 different antibiotics. All genotypic and phenotypic typing methods were analyzed for their ability to discriminate between the isolates. Macrorestriction analysis proved to be the most discriminatory single method (D = 0.96) followed by rRNA spacer typing (D = 0.85), coa PCR (D = 0.82), and spa PCR (D = 0.80).