Methicillin-Resistant Staphylococcus aureus in Raw Milk: Prevalence, SCCmec Typing, Enterotoxin Characterization, and Antimicrobial Resistance Patterns

Abstract

Staphylococcus aureus is a known major cause of foodborne illnesses, and raw milk and dairy products are often contaminated by enterotoxigenic and antimicrobial-resistant S. aureus strains. In the present study, 35 S. aureus strains were isolated from 383 raw milk samples collected from various dairy herds in the province of Milan (northern Italy). The isolates were characterized based on their antimicrobial susceptibility patterns and the presence of genes encoding staphylococcal enterotoxins (sea, seb, sec, sed, and see). About half (45.7%) of the strains were enterotoxigenic, and 37.1% were resistant to at least one of the antimicrobial drugs tested. Seven (20%) of 35 isolates were identified as methicillin-resistant S. aureus (MRSA), and SCCmec typing performed with a multiplex PCR assay revealed the presence of gene cassettes IV and V, typical of communityacquired MRSA, and I and II, characteristic of health care-associated MRSA. The MRSA strains were evaluated for the presence of the Panton-Valentine leukocidin gene, but this gene was not found. The results of the present study revealed the presence of toxin-producing S. aureus and MRSA strains in raw milk. MRSA and enterotoxigenic S. aureus in dairy farms are an important risk factor for the spread of staphylococcal infections; therefore, further studies are needed to find strategies for monitoring and controlling the presence of S. aureus, especially MRSA, in dairy products.

<p>Genotypic and Phenotypic-Based Assessment of Antibiotic Resistance and Profile of Staphylococcal Cassette Chromosome <em>mec</em> in the Methicillin-Resistant <em>Staphylococcus aureus</em> Recovered from Raw Milk</p>

“…34 Findings of the existing investigation revealed that the contamination rate of milk samples was 4.74% (28/590). Incidence of the MRSA in raw milk samples in our survey was lower than those of Italy (20%) 35 and Turkey (17%), 36 while it was higher than those of England (2.30%) 37 and Germany (2.30%). 38 Investigations conducted in the US along with other countries, including North America, Canada, Africa, Asia and Europe, have recovered MRSA mostly from dissimilar kinds of food and dairy samples.…”

The Prevalence and Antibiotic Resistance of Methicillin-Resistant Staphylococcus aureus (MRSA) in Milk and Dairy Products in Balikesir, Turkey

“…Daka et al (2012) (Daka et al, 2012) and higher from other (Vyletelova et al, 2011, Paterson et al, 2012, Kanaan and Al-Shammary 2013, Riva et al, 2015, Cortimiglia et al, 2016. The reports on the prevalence of MRSA in milk and dairy products vary significantly between different studies and different countries or even among regions within the same country where they carried out and even among herds within the same region.…”

Molecular typing, phenotypic and genotypic assessment of antibiotic resistance and virulence factors amongst the Staphylococcus aureus bacteria isolated from raw chicken meat

“…DG Amoako, AM Somboro, AL Abia, C Molechan, K Perrett, LA Bester and SY Essack[26] reported that the S. aureus bacteria isolated from poultry products harbored the highest incidence of resistance toward tetracycline(61.67%), penicillin G (55.83%), erythromycin (54.17%), clindamycin (43.33%), rifampicin (40.83%), doxycycline (36.67%), ampicillin (34.17%), amikacin (30.83%), moxi oxacin (30.83%), trimethoprim-sulfamethoxazole (30.00%), levo oxacin (23.33%), cipro oxacin (15.83%), gentamicin (8.33%) and cefoxitin (7.50%). Surveys conducted on America, Asia, Africa, and Europe continents revealed the high incidence of antibiotic resistant-S. aureus in foods with animal origins[27,28]. Similar pattern of resistance of S. aureus bacteria isolated from different kinds of foodstuff and clinical samples have been reported toward uoroquinolones, aminoglycosides, macrolides…”