From cattle to pastirma: Contamination source of methicillin susceptible and resistant Staphylococcus aureus (MRSA) along the pastirma production chain

Pathogenic potential of meat-borne coagulase negative staphylococci strains from slaughterhouse to fork

This study aimed to determine the prevalence of coagulase-negative staphylococci (CoNS) in meat processing lines for their pathogenic potential associated with biofilm formation, staphylococcal toxin genes, and antibiotic resistance in obtained isolates. Out of 270 samples, 56 isolates were identified as staphylococcal with their species level, and their antimicrobial resistance profiles were also determined with the BD Phoenix™ system. Among these, CoNS were found in 32 isolates, including S. epidermidis (22%), S. warneri (22%), S. cohnii (9%), S. schleiferi (9%), S. capitis (6%), S. haemolyticus (6%), S. lugdunensis (6%), S. chromogenes (6%), S. kloosii (3%), S. sciuri (3%), S. lentus (3%), and S. caprae (3%). Biofilm formation was observed in 78.1% of CoNS isolates, with 56% being strong biofilm producers; and the frequency of the icaA, fnbA, and fnbB genes were 43.7% and 34.3%, and 9.3% in isolates, respectively. Twenty-five (78.1%) of these strains were resistant to at least one antimicrobial agent, 20 (80%) of which exhibited multidrug resistance (MDR). Regarding genotypic analyses, 15.6%, 22.2%, 87.5%, and 9% of isolates, were positive for blaZ, ermC, tetK, and aacA-aphD, respectively. In 8 (25%) of all isolates had one or more staphylococcal toxin genes: the sed gene was the most frequent (12.5%), followed by eta (9.3%), tst-1 (6.25%), and sea (3.1%). In conclusion, this study highlights meat; and meat products might be reservoirs for the biofilm-producing MDR-CoNS, which harbored several toxin genes. Hence, it should not be ignored that CoNS may be related to foodborne outbreaks.

Bacteriocinogenic anti-listerial properties and safety assessment of Enterococcus faecium and Lactococcus garvieae strains isolated from Brazilian artisanal cheesemaking environment

AIMS

This study aimed to prospect and isolate lactic acid bacteria (LAB) from an artisanal cheese production environment, to assess their safety, and to explore their bacteriocinogenic potential against Listeria monocytogenes.

METHODS AND RESULTS

Samples were collected from surfaces of an artisanal-cheese production facility and after rep-PCR and 16S rRNA sequencing analysis, selected strains were identified as to be belonging to Lactococcus garvieae (1 strain) and Enterococcus faecium (14 isolates, grouped into three clusters) associated with different environments (worktables, cheese mold, ripening wooden shelves). All of them presented bacteriocinogenic potential against L. monocytogenes ATCC 7644 and were confirmed as safe (γ-hemolytic, not presenting antibiotic resistance, no mucus degradation properties, and no proteolytic or gelatinase enzyme activity). Additionally, cell growth, acidification and bacteriocins production kinetics, bacteriocin stability in relation to different temperatures, pH, and chemicals were evaluated. According to performed PCR analysis all studied strains generated positive evidence for the presence of entA and entP genes (for production of enterocins A and enterocins P, respectively). However, pediocin PA-1 associated gene was recorded only in DNA obtained from E. faecium ST02JL and Lc. garvieae ST04JL.

CONCLUSIONS

It is worth considering the application of these safe LAB or their bacteriocins in situ as an alternative means of controlling L. monocytogenes in cheese production environments, either alone or in combination with other antimicrobials.