Occurrence and antibiotic resistance of enterotoxigenic Staphylococcus aureus in raw ovine and caprine milk in Greece

Abstract

Ovine (n=140) and caprine (n=35) raw bulk tank milk samples from farms in central Greece were examined for the occurrence of enterotoxigenic Staphylococcus aureus. The S. aureus isolates were screened for staphylococcal enterotoxin (SE) production, the presence of enterotoxin genes, antibiotic resistance (AR), and methicillin resistance. S. aureus was isolated from 24.3% and 31.4% of ovine and caprine milk samples, respectively. Among the S. aureus isolates of ovine milk (n=34) and caprine (n=11) milk, the enterotoxigenic (SEA-SED) isolates were 21 (61.8%) and 7 (63.6%) for the ovine and caprine milk, respectively. Most toxigenic isolates harbored more than one toxin gene and a total of 11 distinct toxinotypes were detected. The most frequent toxin-gene combinations were "sec, tst" (8 isolates), "seb, seg, sei, tst" (4), "seb, seg, sei" (3), and "seb" (3). Six isolates displayed multiple AR towards up to five antimicrobials. Among ovine milk isolates, the highest resistance frequency was observed towards erythromycin (11.8% of the isolates) and tetracycline (8.8%). Among caprine milk isolates, the most frequent resistance was observed towards erythromycin (18.2%). One methicillin-resistant S. aureus (MRSA) isolate was detected in an ovine milk sample and belonged to spa type t4038. This spa type

Prevalence and characterization of methicillin-resistant Staphylococcus aureus carrying mecA or mecC and methicillin-susceptible Staphylococcus aureus in dairy sheep farms in central Italy

“…Despite this high overall S. aureus prevalence, the estimated MRSA prevalence was low (0.7%; 2/286). This finding is in agreement with those of other recent investigations carried out on small ruminant BTM in Italy (Caruso et al, 2015;Cortimiglia et al, 2015), Spain (Ariza-Miguel et al, 2014), and Greece (Pexara et al, 2015;Zdragas et al, 2015), which reported prevalence rates ranging from 0 to 2%.…”

“…As for the antimicrobial susceptibility testing of the MSSA isolates, we found that 60.58% of them were susceptible to all the drugs tested. Lower rates of antimicrobial resistance have been reported in other studies conducted in Greece (Pexara et al, 2015;Zdragas et al, 2015) and Brazil (Martins et al, 2015). The most common resistance was that to tetracycline, observed in 22.12% of the isolates, a rate higher than that described in other studies in Italy (Lollai et al, 2008), Turkey (Ünal et al, 2012, and Brazil (Martins et al, 2015), but lower than that reported in Iran by Jamali et al (2015).…”

“…In this survey, conducted in dairy sheep farms located in central Italy, we found a high prevalence of S. aureus contamination in ovine BTM (53.5% of samples tested). Other studies conducted on BTM in different countries have reported lower prevalence rates, ranging from 9.6 to 33.3% (Muehlherr et al, 2003;Scherrer et al, 2004;de Garnica et al, 2013;Pexara et al, 2015;Zdragas et al, 2015).…”

“…Although S. aureus is frequently isolated from sheep raw milk and dairy products (Morandi et al, 2009;Spanu et al, 2014;Carfora et al, 2015;Jamali et al, 2015), the detection of MRSA in ovine milk (Ariza-Miguel et al, 2014;Caruso et al, 2015;Pexara et al, 2015;Carfora et al, 2016) and derived dairy products (Normanno et al, 2007;Shanehbandi et al, 2014;Carfora et al, 2015) is sporadic.…”

Detection of Enterotoxin Genes and Methicillin‐Resistance inStaphylococcus aureusIsolated from Water Buffalo Milk and Dairy Products

“…() found the presence of the seb gene in one isolate only and they reported that all other genes ( sea , sec , sed , and see ) were not detected in any isolate. Several studies described that none of the investigated isolates from bovine and goat milk and dairy products harbored the gene seb (Akineden et al., ; Lyra et al., ; Pexara, Solomakos, Sergelidis, Angelidis, & Govaris, ). In other studies, however, the seb gene was detected in S. aureus isolates from milk and dairy products at various frequencies (Arcuri et al., ; Jorgensen et al., ; Peles et al., ; Rall et al., ; Zouharova & Rysanek, ).…”