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Abstract Staphylococcal food poisoning (SFP) is one of the most common food-borne diseases and results from the ingestion of staphylococcal enterotoxins (SEs) preformed in food by enterotoxigenic strains of Staphylococcus aureus. To date, more than 20 SEs have been described: SEA to SElV. All of them have superantigenic activity whereas half of them have been proved to be emetic, representing a potential hazard for consumers. This review, divided into four parts, will focus on the following: (1) the worldwide story of SFP outbreaks, (2) the characteristics and behaviour of S. aureus in food environment, (3) the toxinogenic conditions and characteristics of SEs, and (4) SFP outbreaks including symptomatology, occurrence in the European Union and currently available methods used to characterize staphylococcal outbreaks. This review focuses on the importance of food poisonings due to staphylococcal enterotoxins: After a review of worldwide outbreaks due to coagulase positive staphylococci and their toxins, various parts such as characteristics and behavior of S. aureus in food environment, toxinogenic conditions and characteristics of staphylococcal enterotoxins, symptomatology, occurrence, reporting system including European Union control and monitoring schemes are presented.

The presence of Staphylococcus spp. has increasingly been repor ted in food products and poses a public health threat. The aim of this study was to determine the diversity of Staphylococcus spp. and the antibiotic resistance profiles of isolates obtained from freshly harvested and packed readyto-eat mushrooms (n=432) and handlers' hands (n=150). A total of 56 Staphylococcus isolates [46.4% (n=26) from hands and 53.6% (n=30) from mushrooms] were recovered belonging to 10 species. Staphylococcus succinus isolates (n=21) were the most prevalent, of which 52.4% came from mushrooms and 47.6% from hands. This was followed by S. equorum isolates [n=12; 91.7% (n=11) from mushrooms and 8.3% (n=1) from hands] and S. saprophyticus [n=9; 66.7% (n=6) from mushrooms and 33.3% (n=3) from hands]. Six isolates that were characterised as multidrug resistant were isolated from hands of handlers. Most (83.9%; n=47) of the 56 isolates were resistant to penicillin [53.2% (n=25) from mushrooms and 46.8% (n=22) from hands] and 14.3% (n=8) were resistant to cephalosporin classes [25% (n=2) from mushrooms and 75% (n=6) from hands], both of which are used to treat staphylococcal infections. Antibiotic resistance genes blaZ [25.0% (n=14) of all isolates of which 71.4% (n=10) were from hands and 28.57% (n=4) from mushrooms], tetL and tetK [both 1.8% (n=1) from hands], mecA [5.4% (n=3) from hands] and ermA [1.8% (n=1) from mushrooms] were detected from the 56 isolates. Only two (25.0%) of the eight methicillin-resistant staphylococci harboured the mecA gene, while only 11 (23%) of the 47 penicillin-resistant isolates harboured the blaZ gene [36.4% (n=4) from mushrooms and 63.6% (n=7) from hands]. Our results demonstrate that food handlers and harvested and packed ready-to-eat mushrooms could be a source of diverse Staphylococcus spp. that exhibit antimicrobial resistance. Clinically relevant S. aureus was only detected on one handler's hand; however, the isolate was not multidrug resistant. The presence of diverse Staphylococcus spp. on mushrooms and the hands of handlers is a potential public health concern due to their potential to cause oppor tunistic infections.Significance: • This study is the first to describe the antibiotic resistance profiles and antibiotic gene presence of Staphylococcus spp. isolated from fresh mushrooms and hands of pickers and packers. Mushrooms and handlers in this study were demonstrated to be possible routes of transmission of Staphylococcus spp. that are antibiotic resistant and which harbour antibiotic resistance genes, presenting a possible public health hazard.

The capacity for biofilm formation is one of the crucial factors of staphylococcal virulence. The occurrence of biofilm-forming staphylococci in raw milk may result in disturbances in technological processes in dairy factories as well as the contamination of finished food products. Therefore, this study aimed to determine the prevalence and characteristics of staphylococcal biofilm formation in raw milk samples and to explore the genetic background associated with biofilm formation in those isolates. The material subjected to testing included 30 cow’s milk samples acquired from farms in the central part of Poland. A total of 54 staphylococcal strains were isolated from the samples, of which 42 were classified as coagulase-negative (CoNS) staphylococci belonging to the following species: S. haemolyticus, S. simulans, S. warneri, S. chromogenes, S. hominis, S. sciuri, S. capitis, S. xylosus and S. saprophyticus, while 12 were classified as S. aureus. The study examined the isolates’ capacity for biofilm formation and the staphylococcal capacity for slime production and determined the presence of genetic determinants responsible for biofilm formation, i.e., the icaA, icaD, bap and eno and, additionally, among coagulase-negative staphylococci, i.e., the aap, bhp, fbe, embP and atlE. Each tested isolate exhibited the capacity for biofilm formation, of which most of them (79.6%) were capable of forming a strong biofilm, while 5.6% formed a moderate biofilm, and 14.8% a weak biofilm. A capacity for slime production was demonstrated in 51.9% isolates. Most of the tested staphylococcal strains (90.7%) had at least one of the tested genes. Nearly half (47.6%) of the CoNS had the eno gene, while for S. aureus, the eno gene was demonstrated in 58.3% isolates. The frequency of the bap gene occurrence was 23.8% and 25% in CoNS strains and S. aureus, respectively. The fbe gene was demonstrated in only three CoNS isolates. The presence of the icaA was only demonstrated in CoNS strains (24.1%), while the icaD was found in both CoNS strains (21.4%) and S. aureus (100%). Among the CoNS, the presence of the embP (16.7%), aap (28.6%) and atlE (23.8%) was demonstrated as well. The obtained study results indicate that bacteria of the Staphylococcus spp. genus have a strong potential to form a biofilm, which may pose a hazard to consumer health.

Although coagulase-positive staphylococci are considered to be the main factor responsible for food poisoning, an increasing role for the coagulase-negative staphylococci in the production of enterotoxins has been observed in recent years. This study was conducted to assess the occurrence of genes responsible for the production of staphylococcal enterotoxins (SE), enterotoxin-like toxins (SEI) and toxic shock syndrome toxin-1 (TSST-1) in coagulase-negative staphylococci (CoNS) isolated from ready-to-eat food from bars and restaurants. One hundred and eighteen CoNS strains were tested using polymerase chain reaction (PCR) to five superantigenic toxin genes, including five different types of classical enterotoxins (sea, seb, sec, sed and see) and the toxic shock syndrome toxin-1 (tsst-1) as well as to supertoxin-like genes. PCR-positive isolates were then tested using immunoenzymatic methods (SET-RPLA, Vidas SET 2) for toxin expression. Out of 118 CoNS strains, the presence of staphylococcal enterotoxins was confirmed in 72% of them. The most frequently found enterotoxin-like genotype was ser, selu. Two of the tested strains had up to ten different enterotoxin genes in the genome at the same time. Although no production of enterotoxins was detected in the CoNS, which means that their possible role in the epidemiology of food-borne diseases is minimal, the data demonstrated that the toxigenic capacity of the CoNS should not be ignored, and that this group of microorganisms should be continuously monitored in food.

The prevalence of methicillin resistance in staphylococci has been increasing globally and is currently one of the major public health concerns. In particular, treating infections caused by staphylococci with acquired antimicrobial resistance is problematic, as their treatment is more difficult. The resistance is found both in human and animal staphylococcal strains. Methicillin-resistant staphylococci (MRS) have also been increasingly reported in wildlife. In Arab countries, MRS has been detected in food producing animals and food products; however, the risk this poses is somewhat unclear, and still a significant lack of information on the trend and distribution of these pathogens in these countries, which have a specific ecosystem (desert) and traditions (Muslim culture). In this manuscript, we aim to provide an overview of the prevalence and the major MRS clonal lineages circulating in these specific countries and compare to them other situations with different ecosystems and cultures.

BACKGROUND: Methicillin resistance and biofilm-producing Staphylococci are emerging as multidrug-resistant strains narrowing the efficacy of antimicrobial therapy. Although vancomycin is used as the drug of choice to treat such isolates, different studies worldwide have documented the emergence of strains that are intermediately susceptible or resistant to this antibiotic. OBJECTIVE: The study aimed to determine the minimum inhibitory concentration of vancomycin to methicillin-resistant and biofilm-producing staphylococci isolated from different clinical specimens. METHODS: 375 staphylococci isolated from different clinical specimens over one year were included in the study. Biofilm formation was determined by the Tissue culture plate method (TCP), and ica genes were identified by Polymerase Chain Reaction (PCR). Antibiotic susceptibility and methicillin resistance were done following Clinical and Laboratory Standards Institute (CLSI) guidelines. The minimum inhibitory concentration (MIC) of vancomycin in all isolates was determined by the agar dilution method. RESULTS: Among 375 Staphylococci studied, 43% and 57% represented S. aureus and Coagulase-Negative Staphylococci (CNS), respectively. The rate of Methicillin-Resistant S. aureus (MRSA) and Methicillin-Resistant Coagulase Negative Staphylococci (MRCNS) were 81.4% and 66.8% respectively and determined by the disc diffusion method. The most potential antibiotics were tetracycline and chloramphenicol showing sensitivity to more than 90% isolates. The Minimum Inhibitory Concentration (MIC) value of oxacillin for staphylococci ranged from 0.125-32 μg/ml. Oxacillin agar diffusion method showed 51.6% and 79.9% isolates as MRSA and MRCNS, respectively, revealing a very high percentage of S. aureus and CNS isolates as methicillin-resistant. All isolates had susceptible vancomycin MICs that ranged from 0.125-2 μg/ml. Two S. aureus isolated from Central Venous Catheter (CVC) and catheter specimens were detected with intermediate susceptibility to vancomycin. Similarly, three CNS isolated from blood, CVC, and wound/pus (w/p) were intermediately susceptible to vancomycin. Strong biofilm formation was observed in 22.1% of clinical isolates, and the ica gene was detected among 22.9% of isolates. Only one S. aureus detected as a biofilm producer by the TCP method was found to have intermediate susceptibility to vancomycin. CONCLUSIONS: The increment in vancomycin MIC among methicillin-resistant and biofilm-producing staphylococci is alarming. Strict control measures to prevent methicillin-resistant isolates spread and routine surveillance for vancomycin-resistant isolates must be incorporated in hospitals to prevent antimicrobial treatment failure.

Bovine mastitis is one of the most common diseases of dairy cattle. Even though different infectious microorganisms and mechanical injury can cause mastitis, bacteria are the most common cause of mastitis in dairy cows. Staphylococci, streptococci, and coliforms are the most frequently diagnosed etiological agents of mastitis in dairy cows. Staphylococci that cause mastitis are broadly divided into Staphylococcus aureus and non-aureus staphylococci (NAS). NAS is mainly comprised of coagulase-negative Staphylococcus species (CNS) and some coagulase-positive and coagulase-variable staphylococci. Current staphylococcal mastitis control measures are ineffective, and dependence on antimicrobial drugs is not sustainable because of the low cure rate with antimicrobial treatment and the development of resistance. Non-antimicrobial effective and sustainable control tools are critically needed. This review describes the current status of S. aureus and NAS mastitis in dairy cows and flags areas of knowledge gaps.

Staphylococci other than Staphylococcus aureus (SOSA) in animals are becoming more pathogenic and antibiotic resistant and can potentially disseminate to humans. However, there is little synthesized information regarding SOSA from animals in Africa. This systematic review provides a comprehensive overview of the epidemiology and antimicrobial resistance of SOSA in companion animals (pets) and livestock in Africa. This systematic review (PROSPERO-CRD42021252303) was conducted according to the PRISMA guidelines, and 75 eligible studies from 13 countries were identified until August 2022. Three electronic databases (Pubmed, Scopus and Web of Science) were employed. The frequently isolated SOSA were , and . Thirty (40%) studies performed antibiotic susceptibility testing (AST). Penicillin (58%) and tetracycline (28%) resistance were most common across all SOSA with high rates of resistance to aminoglycosides, fluoroquinolones, and macrolides in some species. Resistance to last-resort antibiotics such as linezolid and fusidic acid were also reported. Limited data on strain typing and molecular resistance mechanisms precluded analysis of the clonal diversity of SOSA on the continent. The findings of this review indicate that research on livestock-associated SOSA in Africa is lacking in some regions such as Central and Western Africa, furthermore, research on companion animals and more advanced methods for identification and strain typing of SOSA need to be encouraged. https://www.crd.york.ac.uk/prospero/, identifier: CRD42021252303.

[This corrects the article DOI: 10.3389/fphar.2022.840165.].[This corrects the article DOI: 10.3389/fphar.2022.840165.].

Staphylococci have been implicated in chronic device-related infections due to their ability to form resistant biofilms on implanted medical devices. For a long time, two different mechanisms of biofilm formation were known in Staphylococcus spp., the ica-dependent biofilms in MSSA and CoNS and the ica-independent biofilms in MRSA. Recently, a new fibrin-based biofilm phenotype was identified when S. aureus isolates were allowed to construct biofilms in biologically-relevant conditions using plasma-coated surfaces and RPMI-1640 for biofilm development (RPMI-1640/Pl). In this study, 140 staphylococci clinical isolates (91 MRSA, 27 MSSA and 22 CoNS) were tested for biofilm formation, biofilm formers were selected and used to scrutinize the ability of RPMI-1640/Pl to support staphylococci biofilm formation. Results showed that, in RPMI-1640/Pl, the biofilm formation abilities of MRSA and MSSA isolates were non-significantly different compared to those formed in TSB and BHI, (Kruskal Wallis test, P = 0.3275 and 0.466 for MRSA and MSSA isolates, respectively). However, a significantly different biofilm formation ability was observed regarding the tested CoNS isolates (ANOVA test, P = 0.0006). Furthermore, biofilm formation in RPMI-1640/Pl under different incubation conditions was tested, and among the tested conditions, 48h of static incubation showed significantly elevated biofilm for both MRSA and MSSA. Finally, PCR was used to detect genes implicated in biofilm formation, and the genotypes were correlated to the biofilm formation ability in different tested conditions. In contrast to ordinary media, biofilm formation by staphylococci in RPMI-1640/Pl was positively correlated to coa, fnbA, fnbB and clfB.