Biomaterial Database

Short communication: methicillin-resistant Staphylococcus aureus detection in US bulk tank milk. 2009

J E Virgin, and T M Van Slyke, and J E Lombard, and R N Zadoks

USDA, APHIS, VS, Centers for Epidemiology and Animal Health, Fort Collins, CO 80526-8117, USA.

Staphylococcus aureus is a major cause of mastitis in dairy cattle. This study estimated the herd prevalence of methicillin-resistant Staph. aureus (MRSA) among US dairy herds by testing bulk tank milk (BTM) samples using genotypic and phenotypic methods. A nationally representative sample of 542 operations had BTM cultured for Staph. aureus, and 218 BTM samples were positive upon initial culture. After 4 wk to 4 mo of frozen storage, 87% of 218 samples (n = 190) were still culture positive for Staph. aureus on blood agar, but none were positive for MRSA on the selective indicator medium CHROMagar MRSA. A duplex PCR was used to detect the Staph. aureus-specific nuc gene and the methicillin resistance gene, mecA, in mixed staphylococcal isolates from the 190 BTM samples that were positive for Staph. aureus after storage. Seven samples tested positive for nuc and mecA, and 2 samples tested positive for mecA only. MecA-positive Staphylococcus spp., but not MRSA, were subsequently isolated from 5 samples, whereas neither mecA-positive Staphylococcus spp. nor MRSA was isolated from the remaining 4 samples. Presence of methicillin-resistant, coagulase-negative Staphylococcus spp. may complicate the detection of MRSA by means of PCR on BTM. Bulk tank milk in the United States is not a common source of MRSA.

UI	MeSH Term	Description	Entries
D008892	Milk	The off-white liquid secreted by the mammary glands of humans and other mammals. It contains proteins, sugar, lipids, vitamins, and minerals.	Cow Milk,Cow's Milk,Milk, Cow,Milk, Cow's
D010641	Phenotype	The outward appearance of the individual. It is the product of interactions between genes, and between the GENOTYPE and the environment.	Phenotypes
D002417	Cattle	Domesticated bovine animals of the genus Bos, usually kept on a farm or ranch and used for the production of meat or dairy products or for heavy labor.	Beef Cow,Bos grunniens,Bos indicus,Bos indicus Cattle,Bos taurus,Cow,Cow, Domestic,Dairy Cow,Holstein Cow,Indicine Cattle,Taurine Cattle,Taurus Cattle,Yak,Zebu,Beef Cows,Bos indicus Cattles,Cattle, Bos indicus,Cattle, Indicine,Cattle, Taurine,Cattle, Taurus,Cattles, Bos indicus,Cattles, Indicine,Cattles, Taurine,Cattles, Taurus,Cow, Beef,Cow, Dairy,Cow, Holstein,Cows,Dairy Cows,Domestic Cow,Domestic Cows,Indicine Cattles,Taurine Cattles,Taurus Cattles,Yaks,Zebus
D005260	Female		Females
D005838	Genotype	The genetic constitution of the individual, comprising the ALLELES present at each GENETIC LOCUS.	Genogroup,Genogroups,Genotypes
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D001431	Bacteriological Techniques	Techniques used in studying bacteria.	Bacteriologic Technic,Bacteriologic Technics,Bacteriologic Techniques,Bacteriological Technique,Technic, Bacteriological,Technics, Bacteriological,Technique, Bacteriological,Techniques, Bacteriological,Bacteriologic Technique,Bacteriological Technic,Bacteriological Technics,Technic, Bacteriologic,Technics, Bacteriologic,Technique, Bacteriologic,Techniques, Bacteriologic
D016133	Polymerase Chain Reaction	In vitro method for producing large amounts of specific DNA or RNA fragments of defined length and sequence from small amounts of short oligonucleotide flanking sequences (primers). The essential steps include thermal denaturation of the double-stranded target molecules, annealing of the primers to their complementary sequences, and extension of the annealed primers by enzymatic synthesis with DNA polymerase. The reaction is efficient, specific, and extremely sensitive. Uses for the reaction include disease diagnosis, detection of difficult-to-isolate pathogens, mutation analysis, genetic testing, DNA sequencing, and analyzing evolutionary relationships.	Anchored PCR,Inverse PCR,Nested PCR,PCR,Anchored Polymerase Chain Reaction,Inverse Polymerase Chain Reaction,Nested Polymerase Chain Reaction,PCR, Anchored,PCR, Inverse,PCR, Nested,Polymerase Chain Reactions,Reaction, Polymerase Chain,Reactions, Polymerase Chain
D055624	Methicillin-Resistant Staphylococcus aureus	A strain of Staphylococcus aureus that is non-susceptible to the action of METHICILLIN. The mechanism of resistance usually involves modification of normal or the presence of acquired PENICILLIN BINDING PROTEINS.	MRSA,Methicillin Resistant Staphylococcus aureus