Isolation and characterisation of Staphylococcus aureus strains isolated from beef, sheep and chicken meat

Abstract

Summary:The objective of this study was to evaluate the occurrence, enterotoxigenic properties and antibiotic resistance of Staphylococcus aureus in beef, sheep and chicken meat. For this purpose, 225 meat samples were obtained from different supermarkets in Ankara. Firstly, these samples were analysed phenotypically for coagulase-positive staphylococci and S. aureus. Then phenotypically determined S. aureus isolates were confirmed through PCR assay and investigated by multiplex PCR for enterotoxin genes and mecA gene. According to the analyses, 14.6%, 30.6% and 45.3% of the beef, sheep and chicken meat samples respectively were found to be contaminated with S. aureus. Eighty eight (77.1%) out of 114 S. aureus isolates were determined as enterotoxigenic. Also, isolates contained newly described enterotoxin like genes. These results indicated that new types enterotoxin genes could be effective in establishing food intoxication. In this study, isolates were found resistant to one or more antibiotics. None of the S. aureus isolates contain mecA gene but some of them were identified as resistant to a group of antibiotics like oxacillin and cefoxitin, which are used in determining methicillin resistance. For public health and hygienic meat production HACCP and GMP systems should be implemented effectively.Keywords: Enterotoxin, meat, mecA, PCR, Staphylococcus aureus. Sığır, koyun ve piliç etlerinden Staphylococcus aureus'un izolasyon ve karakterizasyonuÖzet: Bu çalışma sığır, koyun ve piliç etlerinde Staphylococcus aureus'un bulunuşu, enterotoksijenik özellikleri ve antibiyotik dirençliliklerini saptamak amacıyla yapılmıştır. Bu amaçla, Ankara'daki farklı süpermarketlerden 225 adet et örneği alınmıştır. Alınan örnekler öncelikle koagulaz-pozitif stafilokoklar ve S. aureus yönünden analiz edilmiştir. Fenotipik testler sonucu S. aureus olarak belirlenen suşlar PCR tekniği ile doğrulanarak, multipleks PCR tekniği kullanılarak enterotoksin genleri ve mecA geni yönünden analiz edilmiştir. Analiz sonuçlarına göre sığır, koyun ve piliç eti örnekleri S. aureus ile sırasıyla % 14.6, % 30.6 ve % 45.3 düzeyinde kontamine bulunmuştur. İzole edilen 114 adet S. aureus izolatından 88'inin (% 77.1) enterotoksijenik özellikte olduğu tespit edilmiştir. İzolatların yeni tanımlanan enterotoksin genlerine sahip oldukları belirlenmiştir. Sonuçlar, yeni tanımlanan enterotoksin genlerinin gıda intoksikasyonlarında önemli olabileceğini ortaya koymaktadır. Bu çalışmada izolatlar bir veya daha fazla antibiyotiğe dirençli bulunmuştur. S. aureus izolatlarının hiçbirinde mecA geni saptanmamasına karşın, bazı izolatlar metisilin duyarlılığının belirlenmesinde kullanılan, oxacillin ve cefoxitine dirençli bulunmuştur. Halk sağlığının korunması ve hijyenik et üretimi için HACCP ve GMP sistemlerinin etkin uygulanması önemlidir.

The role of food in the spread of the Methicillin – resistant Staphylococcus aureus (MRSA)

“…A study of 40 beef samples in Pakistan showed the presence of Staphylococcus aureus in 75% of the samples and 63% identified resistance to cefoxitin, a marker of MRSA (Sadi et al 2020). Similar data on the prevalence of Staphylococcus aureus in 14.6% beef samples in Turkey were reported by Özdemir and Keyvan (2016). Cefoxitin resistance was found in 22.8% of them.…”

“…Most authors found high resistance to penicillin and ampicillin (up to 100%). The data by erythromycin and tetracycline resistance are similar (Jackson et al 2013;Kim et al 2020;Mahros et al 2021;Özdemir and Keyvan 2016;Wu et al 2019). Antibiotic susceptibility testing showed that most of MRSA isolates from meat samples in Denmark were resistant to erythromycin (95%), tetracycline (84%), and clindamycin (79%), and some were resistant to ciprofloxacin (32%).…”

“…However, at this moment, there are still antibiotics to which MRSA are fully susceptible. Some data shows 100% susceptibility to erythromycin, ciprofloxacin, vancomycin and gentamycin (Jackson et al 2013;Kalupahana et al 2019;OʼBrien et al 2012;Özdemir and Keyvan 2016). This is inconsistent with the results reported by Sadi et al (2020) which reported 80% resistance to vancomycin and 100 % resistance to ciprofloxacin (Table 2).…”

“…The authors detected MRSA in 63% of analysed poultry samples. Iran, Korea, Turkey and Canada were reported different data (Farahmand et al 2020;Kim et al 2020;Özdemir and Keyvan 2016;Wells and Juett 2010). They found MRSA in only 2 samples in Iran, 0.9% in Korea and 1.2% in Canada.…”