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Importance of food handlers as a source of enterotoxigenic staphylococci
Abstract:
The incidence of staphylococci in the nasal fossae of 300 food handlers working within the province of León (Spain) was studied. Sampling was carried out using a swabbing technique. For the quantitative estimation of staphylococci, a direct plating method and an enrichment procedure (MPN) were used simultaneously. Gram positive cocci that fermented glucose and were sensitive to lysostaphin (1 unit/ml) were found to be present in the noses of 201 food handlers (67%). Eighty three of them (27.6%) were carriers of coagulase positive staphylococci and 118 (39.3%) of coagulase negative staphylococci. The carriage rate of coagulase negative staphylococci was slightly higher in winter but carriers of coagulase positive strains were more frequently found during warmer months. Coagulase positive staphylococci appeared to be more often carried by males. In all instances, positive nasal cultures gave 10 or more colonies per sample. The majority of food handlers carrying coagulase negative staphylococci (64.4%) yielded counts between 10(3)-10(5) CFU per swab. Thirty four (40.9%) of the nasal carriers of coagulase positive staphylococci yielded more than 10(4) CFU per sample. The higher counts corresponded to this latter group. Preliminary enrichment did not increase the number of nasal carriers detected. Although a good correlation was observed between the results of direct plating and the MPN procedure (r = 0.87 +/- 0.04), the MPN technique gave lower counts. Thirty six (12%) individuals carried enterotoxigenic staphylococci. The incidence among carriers of coagulase positive strains was 43.4%. The enterotoxin types produced were: A (12 strains), B (8 strains), C (7 strains), D (2 strains), E (2 strains), A + D (4 strains) and B + C (1 strain). Most of the food handlers who harbored enterotoxigenic strains gave high nasal counts.
Insights
A study of 300 food handlers in León, Spain, found 67% carried staphylococci in their noses. Coagulase-positive staphylococci were found in 27.6%, with 12% carrying enterotoxigenic strains.
Area of Science:
- Microbiology
- Food Safety
- Public Health
Background:
- Staphylococci are common bacteria found on human skin and mucous membranes.
- Food handlers can potentially transmit staphylococci, including pathogenic strains, to food.
- Understanding nasal carriage rates is crucial for food safety protocols.
Purpose of the Study:
- To determine the incidence and characteristics of staphylococcal nasal carriage among food handlers in León, Spain.
- To identify the prevalence of coagulase-positive and coagulase-negative staphylococci.
- To assess the presence of enterotoxigenic staphylococci in this population.
Main Methods:
- Nasal swabs were collected from 300 food handlers.
- Direct plating and most probable number (MPN) enrichment methods were used for quantitative estimation.
- Strains were identified based on Gram staining, glucose fermentation, and lysostaphin sensitivity.
- Coagulase testing was performed to differentiate between coagulase-positive and coagulase-negative staphylococci.
- Enterotoxin production was analyzed in positive strains.
Main Results:
- Staphylococci were detected in 67% of food handlers.
- Coagulase-positive staphylococci were carried by 27.6% and coagulase-negative by 39.3%.
- Males showed a higher carriage rate for coagulase-positive strains.
- Enterotoxigenic staphylococci were found in 12% of individuals, with types A, B, C, D, and E identified.
- Higher bacterial counts were observed in carriers of coagulase-positive and enterotoxigenic strains.
Conclusions:
- A significant proportion of food handlers in León carry staphylococci, posing a potential risk in food handling environments.
- The prevalence of coagulase-positive and enterotoxigenic strains highlights the importance of monitoring and control measures.
- Further research into transmission dynamics and effective interventions is warranted to enhance food safety.