Prevalence of enterotoxin-encoding genes and antimicrobial resistance in coagulase-negative and coagulase-positive Staphylococcus isolates from black pudding

Abstract

Introduction: Staphylococcal species are pathogens that are responsible for outbreaks of foodborne diseases. The aim of this study was to investigate the prevalence of enterotoxin-genes and the antimicrobial resistance profile in staphylococcus coagulase-negative (CoNS) and coagulasepositive (CoPS) isolates from black pudding in southern Brazil. Methods: Two hundred typical and atypical colonies from Baird-Parker agar were inoculated on mannitol salt agar. Eighty-two mannitol-positive staphylococci were submitted to conventional biochemical tests and antimicrobial susceptibility profiling. The presence of coagulase (coa) and enterotoxin (se) genes was investigated by polymerase chain reaction. Results: The isolates were divided into 2 groups: 75.6% (62/82) were CoNS and 24.4% (20/82) were CoPS. The biochemical tests identified 9 species, of which Staphylococcus saprophyticus (37.8%) and Staphylococcus carnosus (15.9%) were the most prevalent. Antimicrobial susceptibility tests showed resistance phenotypes to antibiotics widely administered in humans, such as gentamicin, tetracycline, chloramphenicol, and erythromycin. The coa gene was detected in 19.5% (16/82) of the strains and 4 polymorphic DNA fragments were observed. Five CoNS isolates carrying the coa gene were submitted for 16S rRNA sequencing and 3 showed similarity with CoNS. Forty strains were positive for at least 1 enterotoxin-encoding gene, the genes most frequently detected were sea (28.6%) and seb (27.5%). Conclusions: The presence of antimicrobial resistant and enterotoxin-encoding genes in staphylococci isolates from black pudding indicated that this fermented food may represent a potential health risk, since staphylococci present in food could cause foodborne diseases or be a possible route for the transfer of antimicrobial resistance to humans.

Antibiotic resistance and enterotoxin genes in Staphylococcus sp. isolates from polluted water in Southern Brazil

“…Some studies have shown that CNS strains can harbor enterotoxins genes. Moura et al (2012) reported the presence of enterotoxins genes in CNS strains isolated from black pudding. The SE genes were also detected in coagulase negative staphylococci isolated from dairy products in Brazil (Rall et al 2010).…”

“…DNA extractions and polymerase chain reaction (PCRs) for five classical staphylococcal enterotoxins genes (sea, seb, sec, sed and see) were performed as previously described by Moura et al 2012. The S. aureus ATCC 13565, ATCC 14458, ATCC 19095, ATCC 23235 and ATCC 27664 strains were used as positive controls for sea, seb, sec, sed and see genes, respectively.…”

Detection of vanC 1 gene transcription in vancomycin-susceptible Enterococcus faecalis

“…Extraction of DNA and PCR assays - Genomic DNA was extracted following the standard method of phenol (Invitrogen) extraction and ethanol (Pro Analysis) precipitation (Sambrook & Russell 2001) with minor modifications, as previously described (Moura et al 2012). Plasmid DNA was extracted using standard miniprep methods (Sambrook & Russell 2001).…”

A Review on Staphylococcus sp. and its pathogens

“…It is considered an opportunistic bacterium that shows its pathogenic ability in patients with immunocompromised patients, chronic diseases and long-term patients in hospital (Jean-Baptiste et al, 2011), as it enters the bloodstream and causes injuries to the circulatory system, especially in cases associated with the use of some medical devices, such as catheter tubes and blood implants, for hospitalized patients (Al-Mazroea, 2009). It is considered one of the most important bacterial species that cause hospital-acquired infections (Nosocomial Infections), as it is characterized by its ability to grow in thermal ranges from 15-43 • C (Moura et al, 2012;Götz et al, 2006). It has a NaCl tolerance of 15% and is resistant to the minimum inhibitory concentrations of some common antiseptics as well as its multiple resistance to antibiotics.…”

“…They grow naturally in many culture media. Staphylococci are classi ied depending on the production of coagulase coagulation (coagulase) into two main groups (Coagulase, that is, able to produce coagulation enzyme for blood plasma and the second group negative enzyme staphylococcus coagulase which is unable to produce coagulation enzyme for blood plasma (Moura et al, 2012).…”