Staphylococcus aureus and Staphylococcal enterotoxin detection in raw milk and cheese origin coagulase positive isolates

Staphylococcal food poisoning is caused by enterotoxin-producing Staphylococcus aureus. We investigated the prevalence of such organisms in samples of bovine mastitic milk (n = 714), raw meat (n = 139), and vegetables (n = 616). We determined the degrees of relatedness of isolates as indicated by antibiogram, staphylococcal enterotoxin (SE) productivity, and coagulase gene restriction fragment length polymorphism analysis. We examined 297 S. aureus isolates and found SE production in 57 (31.8%), 4 (7.8%), and 49 (73.1%) isolates from raw milk, raw meat, and vegetables, respectively. A high proportion of the isolates obtained from milk produced more than two types of toxins (mainly SEA, SEB, and/or SEC), whereas isolates from raw meat and vegetables primarily produced SEA alone. Most isolates were sensitive to cephalothin (97.6%), gentamicin (80.8%), erythromycin (79.5%), and tetracycline (72.7%), but were resistant to penicillin (90.2%) and ampicillin (88.9%). The proportion of antibiotic-resistant isolates differed according the source of the bacteria; the milk and vegetable isolates were more resistant to penicillin and ampicillin than were the meat isolates (P < 0.05), whereas tetracycline resistance was limited to the milk and vegetables isolates. The coagulase genotypes (I to XII) varied with the source of the organism, and only a few genotypes prevailed in each source: II (42.4%) and IV (24%) types in isolates from milk, IX (35.3%) and XI (45%) from raw meat, and III (40.3%) and XII (32.8%) from vegetables. These findings suggest that remarkable differences exist in antibiogram, SE productivity, and coagulase genotypes, resulting in limited clonal transmission of S. aureus into various food sources. As enterotoxin production only occurs when S. aureus grows to high numbers, staphylococcal food poisoning can be prevented by proper refrigeration.

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Characterization of Staphylococcus aureus Strains Isolated from Raw Milk Utilized in Small-Scale Artisan Cheese Production

Journal of Food Protection ◽

10.4315/0362-028x.jfp-10-533 ◽

2011 ◽

Vol 74 (8) ◽

pp. 1353-1358 ◽

Cited By ~ 13

Author(s):

DENNIS J. D'AMICO ◽

CATHERINE W. DONNELLY

Keyword(s):

Staphylococcus Aureus ◽

Antimicrobial Resistance ◽

Phenotypic Diversity ◽

Raw Milk ◽

Staphylococcal Enterotoxin ◽

Small Scale ◽

Enterotoxin Production ◽

Type C ◽

Cheese Production

Staphylococcus aureus is an important agent of bacterial mastitis in milking animals and of foodborne intoxication in humans. The purpose of this study was to examine the genetic and phenotypic diversity, enterotoxigenicity, and antimicrobial resistance of S. aureus strains isolated from raw milk used for the production of artisan cheese in Vermont. Cross-tabulations revealed that the 16 ribotypes identified among the 90 milk isolates examined were typically associated with a specific animal species and that more than half of these ribotypes were unique to individual farms. In general, specific EcoRI ribotypes were commonly associated with specific phenotypical characteristics, including staphylococcal enterotoxin production or the lack thereof. Limited antimicrobial resistance was observed among the isolates, with resistance to ampicillin (12.51%) or penicillin (17.04%) most common. Two isolates of the same ribotype obtained from the same farm were resistant to oxacillin with 2% NaCl. More than half (52.22%) of isolates produced toxin, and 31 of the 32 isolates solely produced staphylococcal enterotoxin type C. Although these data demonstrate that S. aureus strains found in raw milk intended for artisan cheese manufacture are capable of enterotoxin production, staphylococcal enterotoxin C is not typically linked to foodborne illness. Because S. aureus is a common contaminant of cheese, an understanding of the ecology of this pathogen and of the antimicrobial susceptibility and toxigenicity of various strains will ultimately contribute to the development of control practices needed to enhance the safety of artisan and farmstead cheese production.

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Staphylococcal Enterotoxin A Gene–Carrying Staphylococcus aureus Isolated from Foods and Its Control by Crude Alkaloid from Papaya Leaves

Journal of Food Protection ◽

10.4315/0362-028x.jfp-13-483 ◽

2014 ◽

Vol 77 (11) ◽

pp. 1992-1997 ◽

Cited By ~ 1

Author(s):

LITA HANDAYANI ◽

DIDAH NUR FARIDAH ◽

HARSI D. KUSUMANINGRUM

Keyword(s):

Staphylococcus Aureus ◽

Food Poisoning ◽

Dry Weight ◽

Raw Milk ◽

Staphylococcal Enterotoxin ◽

Staphylococcal Enterotoxin A ◽

Assisted Extraction ◽

Ultrasonic Assisted ◽

Broth Macrodilution ◽

Ultrasonic Assisted Extraction

Staphylococcus aureus is a known pathogen causing intoxication by producing enterotoxins in food. Staphylococcal enterotoxin A is one of the enterotoxins commonly implicated in staphylococcal food poisoning. The ability of crude alkaloid extract from papaya leaves to inhibit the growth of S. aureus and staphylococcal enterotoxin A synthesis was investigated. Staphylococcal enterotoxin A gene–carrying S. aureus was isolated from raw milk and ready-to-eat foods. Crude alkaloid was extracted from ground, dried papaya leaves using ultrasonic-assisted extraction, and a MIC of the alkaloid was determined by the broth macrodilution method. Furthermore, S. aureus isolate was exposed to the crude alkaloid extract at one- and twofold MIC, and the expression of sea was subsequently analyzed using a quantitative reverse transcription real-time PCR. Ten isolates of S. aureus were obtained, and nine of those isolates were sea carriers. The yield of crude alkaloid extract was 0.48 to 1.82% per dry weight of papaya leaves. A MIC of crude alkaloid to S. aureus was 0.25 mg/ml. After exposure to the alkaloid at 0.25 and 0.5 mg/ml for 2 h, a significant increase in cycle threshold values of sea was observed. The sea was expressed 29 and 41 times less when S. aureus was exposed to crude alkaloid at one- and twofold MIC, respectively. This study revealed that crude alkaloid of papaya leaves could control staphylococcal enterotoxin A gene–carrying S. aureus by suppressing the expression of sea, in addition to the ability to inhibit the growth of S. aureus. The expression of sea was successfully quantified.

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Effect of Scalding Temperature on Growth of Staphylococcus aureus and Formation of Staphylococcal Enterotoxin during the Production of Alpine Cheese in a Laboratory Cheesemaking Model

Journal of Food Protection ◽

10.4315/jfp-19-600 ◽

2020 ◽

Vol 83 (10) ◽

pp. 1822-1828

Author(s):

LIVIA SCHWENDIMANN ◽

THOMAS BERGER ◽

HANS-ULRICH GRABER ◽

SUSANN MEIER ◽

JÖRG HUMMERJOHANN ◽

...

Keyword(s):

Staphylococcus Aureus ◽

Peripheral Zone ◽

Raw Milk ◽

Temperature Curve ◽

Staphylococcal Enterotoxin ◽

Production Experiment ◽

Strain Type ◽

Coagulase Positive Staphylococci ◽

Cheese Production ◽

Hard Cheese

ABSTRACT To reduce the number of cheese with potential Staphylococcus aureus contamination reaching consumers, European legislation has stipulated that all cheese must be tested for coagulase-positive staphylococci (CPS) at the point in production when numbers are expected to be highest. When CPS counts exceed 105 CFU/mL, staphylococcal enterotoxin (SE) tests must be conducted. When SE tests are positive, the cheese must be destroyed. Manufacturers of Swiss Alpine cheese are exempt from this legislation because SE formation in hard cheese is expected to be very unlikely because of the high scalding temperatures used for cheeses during production, which inactive CPS in the curd. However, this assumption has not been scientifically tested. A laboratory-scale cheese production experiment was performed in which the conditions corresponded to certain limitations in practical cheesemaking conditions such as temperature and time exposure as for production of Gruyere or Tete de Moine Swiss type cheeses. Raw milk aliquots (200 mL) were inoculated with five strains of CPS, and scalding temperatures of 46 to 56°C were used during cheese production. The temperatures applied after the curd was pressed were meant to reproduce the temperature curve in the peripheral zone of a real cheese wheel. Contrary to expectations, SE formation occurred and differed according to the scalding temperature (52 to 56°C). The differences in SE formation were more associated with strain type rather than temperature. These results indicate that the mechanisms of SE formation in cheese require further study. HIGHLIGHTS

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Quantitative Microbial Risk Assessment for Staphylococcus aureus and Staphylococcus Enterotoxin A in Raw Milk

Journal of Food Protection ◽

10.4315/0362-028x-72.8.1641 ◽

2009 ◽

Vol 72 (8) ◽

pp. 1641-1653 ◽

Cited By ~ 32

Author(s):

JOELLE C. HEIDINGER ◽

CARL K. WINTER ◽

JAMES S. CULLOR

Keyword(s):

Risk Assessment ◽

Staphylococcus Aureus ◽

Raw Milk ◽

Staphylococcal Enterotoxin ◽

Milk Consumption ◽

Quantitative Microbial Risk Assessment ◽

Staphylococcal Enterotoxin A ◽

Microbial Risk Assessment ◽

Microbial Risk ◽

Consumer Risk

A quantitative microbial risk assessment was constructed to determine consumer risk from Staphylococcus aureus and staphylococcal enterotoxin in raw milk. A Monte Carlo simulation model was developed to assess the risk from raw milk consumption using data on levels of S. aureus in milk collected by the University of California–Davis Dairy Food Safety Laboratory from 2,336 California dairies from 2005 to 2008 and using U.S. milk consumption data from the National Health and Nutrition Examination Survey of 2003 and 2004. Four modules were constructed to simulate pathogen growth and staphylococcal enterotoxin A production scenarios to quantify consumer risk levels under various time and temperature storage conditions. The three growth modules predicted that S. aureus levels could surpass the 105 CFU/ml level of concern at the 99.9th or 99.99th percentile of servings and therefore may represent a potential consumer risk. Results obtained from the staphylococcal enterotoxin A production module predicted that exposure at the 99.99th percentile could represent a dose capable of eliciting staphylococcal enterotoxin intoxication in all consumer age groups. This study illustrates the utility of quantitative microbial risk assessments for identifying potential food safety issues.

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Occurrence, enterotoxin production and antimicrobic susceptibility of Staphylococcus aureus isolates from domestic cheeses in the Dubrovnik area

Veterinarska stanica ◽

10.46419/vs.53.2.3 ◽

2021 ◽

Vol 53 (2) ◽

Author(s):

Ivana Ljevaković-Musladin ◽

Marina Vodnica-Martucci ◽

Marija Krilanović ◽

Lidija Kozačinski

Keyword(s):

Staphylococcus Aureus ◽

Food Poisoning ◽

Epidemiological Data ◽

Raw Milk ◽

Latex Agglutination ◽

Staphylococcal Enterotoxin ◽

Contamination Level ◽

Enterotoxin Production ◽

Wide Range ◽

High Level

Staphylococcus aureus is a well-known op¬portunistic pathogen that causes a wide range of acute and chronic diseases in both humans and animals. Staphylococcal food poisoning is just one of many diseases caused by this bacterium. The causative agents are entero¬toxins produced by enterotoxigenic strains of S. aureus during its growth in favourable conditions in food. Epidemiological data show that S. aureus is often found in raw milk cheeses and accordingly, cheeses are often implicated in food poisoning outbreaks. Since there are no data on the nature of S. aureus isolated from cheese produced in Croatia, the aim of this study was to determine the occur¬rence, enterotoxin production capability and antimicrobic susceptibility of S. aureus iso¬lates from domestic cheeses produced in the Dubrovnik area. A total of 30 cheese samples were analysed, and 18 samples (60%) were highly contaminated with S. aureus strains. The contamination level ranged from 3.94 to 6.26 log10 cfu/g. Such a high level of contami¬nation was supported by an inappropriate temperature regime above 8°C during market sale. Although highly contaminated, staphy¬lococcal enterotoxins were not detected in any of the cheese samples. A total of 180 coagu¬lase-positive isolates were collected from 18 cheese samples, 175 of which were confirmed as S. aureus by the latex agglutination test. En¬terotoxin production was detected in 35 iso¬lates (20%), and of these 32 isolates produced staphylococcal enterotoxin C. The other three isolates presumably produced enterotoxin E. Antibiotic resistance was detected in 1.1% of isolates and only to mupirocin. However, a full comprehensive conclusion on the nature of S. aureus isolates cannot be achieved with¬out determining its genotype characteristics for the presence of staphylococcal enterotoxin genes and molecular typing, to determine the origin of the isolates.

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Phylogeny Characterization of Seb Gene Encoding Enterotoxins in Staphylococcus aureus Isolated from Raw Milk and Cheese

International Journal of Drug Delivery Technology ◽

10.25258/ijddt.v9i3.13 ◽

2019 ◽

Vol 9 (o3) ◽

Author(s):

Fatima N. Aziz ◽

Laith Abdul Hassan Mohammed-Jawad

Keyword(s):

Staphylococcus Aureus ◽

Food Poisoning ◽

Raw Milk ◽

Staphylococcal Enterotoxin B ◽

Human Pathogen ◽

Conventional Pcr ◽

Biochemical Tests ◽

Specific Primers ◽

Gene Encoding

Food poisoning due to the bacteria is a big global problem in economically and human's health. This problem refers to an illness which is due to infection or the toxin exists in nature and the food that use. Milk is considered a nutritious food because it contains proteins and vitamins. The aim of this study is to detect and phylogeny characterization of staphylococcal enterotoxin B gene (Seb). A total of 200 milk and cheese samples were screened. One hundred ten isolates of Staphylococcus aureus pre-confirmed using selective and differential media with biochemical tests. Genomic DNA was extracted from the isolates and the SEB gene detects using conventional PCR with specific primers. Three staphylococcus aureus isolates were found to be positive for Seb gene using PCR and confirmed by sequencing. Sequence homology showed variety range of identity starting from (100% to 38%). Phylogenetic tree analyses show that samples (6 and 5) are correlated with S. epidermidis. This study discovered that isolates (A6-RLQ and A5-RLQ) are significantly clustered in a group with non- human pathogen Staphylococcus agnetis.

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