Characterization for enterotoxin production, virulence factors, and antibiotic susceptibility of Staphylococcus aureus isolates from various foods in Portugal

Abstract

Staphylococcus aureus represents a public health challenge worldwide. The aim of this study was the characterization of different food isolates of S. aureus on the basis of their production of enterotoxins, hemolysins and resistance to antibiotics. A total of 148 coagulase-positive staphylococcal strains isolated from different food origins were identified to the species level. By multiplex PCR, 69% of the isolates were shown to be enterotoxigenic (SEs); the most common were sea seg, sea seg sei and seg sei. According to CLSI [CLSI, Clinical and Laboratory Standards Institute, 2007. Performance Standards for Antimicrobial Susceptibility Testing; Fifteenth Informational Supplement. CLSI document M100-S15. Clinical and Laboratory Standards Institute, Wayne, PA], 38% of the isolates were resistant to oxacillin (>or= 6 microg/mL; MRSA positives) but only 0.68% showed the presence of mecA gene. 70 and 73% of the S. aureus strains were resistant to beta-lactams, ampicillin and penicillin, respectively. The virulence pattern was demonstrated to be origin and strain dependent. These findings emphasise the need to prevent the presence of S. aureus strains and SEs production in foods.

Prevalence and antibiogram study of Salmonella and Staphylococcus aureus in poultry meat

“…Samples (25 g) were transferred to 225 mL of buffered peptone water (BPW) and mixed (IKA Labortechnik Germany) for 10 min at 120 r/min, the mixture sample were incubated at 37 °C for [18][19][20][21][22][23][24] h. Part of inoculated BPW was transferred to two separate enrichment media for isolation of Salmonella and S. aureus.…”

“…Bacterial suspensions were spread on mueller-hinton agar (Merck, Germany). The antibiotic discs were placed over the lawn and incubated at 37 °C for [18][19][20][21][22][23][24] …”

“…It is necessary to monitor the prevalence and antimicrobial resistance of foodborne pathogens for effective food safety planning and targeted interventions [7] . Food plays an important role in the transfer of antibiotic resistance in term of antibiotic residues or transfer of resistant genes from food microflora to pathogenic bacteria [18] . The objective of this study is to reveal the presence of potential foodborne pathogens Salmonella and S. aureus in the retail poultry meat in Thailand and furthermore to evaluate the antimicrobial resistance and sensitivity pattern of these pathogens.…”

Methicillin-resistant Staphylococcus spp. isolated from curd cheese “requeijão” and “especialidade láctea type requeijão” sold in Brazil

“…Presence of Staphylococcus spp. and S. aureus DNA molecules was detected using primers 16SrRNA (Pereira et al, 2009) SASAKI et al (2010) (Table 1). In order to detect methicillinresistant isolates (mecA), a PCR was performed using the primers as described by GORTEL et al (1999): 5' AAA ATC GAT GGT AAA GGT TGG C 3' e 5' AGT TCT GCA GTA CCG GAT TTG C 3', with a 533bp product and 55°C annealing temperature.…”

“…A set of 57 isolates were subjected to a PCR in order to confirm if they were Staphylococcus spp. (PEREIRA et al, 2009) (SASAKI et al, 2010). In total 54 isolates were confirmed as Staphylococcus spp.…”