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Food handlers nasally carrying S. aureus spur hand contamination
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Food handlers who carry Staphylococcus aureus in their noses are a likely source of hand contamination in their workplace, according to data recently published in the American Journal of Infection Control.
“Hand contamination of food handlers with [S. aureus] is an important risk factor for staphylococcal food poisoning.” Margaret M. O’Donoghue, PhD, assistant professor in the School of Nursing, The Hong Kong Polytechnic University, and colleagues wrote. “Hands may act as vectors, transferring the organism to food where enterotoxins may be formed and result in acute gastroenteritis on ingestion. Nasal carriers and contaminated foods are possible sources of S. aureus contamination. However, studies of S. aureus carriage in food handlers have mainly focused on nasal colonization, with limited investigation of the origins of hand contamination.”
O’Donoghue and colleagues studied 548 food handlers from 14 catering facilities in Hong Kong. Participants were nasally swabbed twice, 3 months to 6 months apart. Those who tested positive with the same S. aureus protein A (spa) type both times were classified as persistent carriers, while those who tested positive once were considered transient carriers. Fingerprint specimens were also collected on the second visit.
The researchers found that 24% of participants were nasally colonized at the second sample and 16.6% had hand contamination. After retraining employees at an establishment with a high rate of hand contamination on proper hand-washing techniques, the overall hand contamination rate dropped to 11.1%.
Of the 53 participants who were classified with hand contamination, four had strains of S. aureus on their hands that matched their nasal strains. Hand isolates of the remaining food handlers without nasal colonization matched the spa type of the nasal isolates in persistently colonized co-workers in 29 cases. Of the other 20 food handlers, 10 had hand contamination that matched the spa types of transient nasal carriers at work.
“By use of a large population of food handlers, repeated sampling to determine carrier status, and use of spa tying, we were able to reveal that persistent nasal carriers are likely to be the most important source of hand contamination, accounting for more than half of the isolates,” O’Donoghue and colleagues wrote. “Such transmission would likely occur indirectly, as a result of nasally contaminated hands of colonized workers contaminating the environment, utensils, or food, which are then in contact with other food handlers.” – by David Jwanier
Disclosure: The researchers report no relevant financial disclosures.
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