Microbial profiling of food contact surfaces in hospitals at Maseru Lesotho

Abstract

Food handlers play a key role in ensuring food safety throughout the food production, processing, storage, and preparation chain. In food service establishments, the common sources of microbial contamination reportedly originate from dirty food contact surfaces, poor personal hygiene practices, and inappropriate storage temperatures. Contamination primarily arises from food contact surfaces such as utensils, equipment, and food handler hands or clothing. The overall purpose of this study was to investigate microbial contamination of food contact surfaces in hospital kitchens in the city of Maseru, Lesotho. The objectives were to assess food handlers’ knowledge, attitudes, and hygiene practices and to characterize prevalent hospital foodborne pathogens associated with food contact surfaces. The study also evaluated the efficacy of common disinfectants against microorganisms and investigated the production of extended-spectrum beta-lactamase (ESBL) against Gram-negative bacteria. The study was conducted in five hospitals involving food handlers ranging between 2-7 per hospital. A total of 26 food handlers participated in the study. A structured questionnaire that had been derived from previous studies was used to assess the food handlers’ knowledge, attitudes, and practices (KAPs). The microbial isolates were identified to specie level by use of biochemical test kits (Staph API, RAPID ONE and RAPID NF Plus). The identified Gram-negative bacteria were subjected to a series of antimicrobials in order to determine the susceptibility profile using the Kirby-Baur disc diffusion method. The phenotypic tests for ESBL detection were used to test for ESBL production with subsequent double disc synergy test used as a confirmation method. Isolates were further subjected to the Kirby-Baur disc diffusion method to establish susceptibility to common disinfectants. Subsequently, the minimum inhibitory concentrations and the minimum bactericidal concentrations were determined by using the in-vitro susceptibility test employing 96-well microtiter plates. More female (n=23; 88%) than male (n=3; 12%) food handlers participated in the study. The majority of these food handlers (n=25; 96%) were aware that proper cleaning and sanitization of utensils decreases the risk of contamination. Although 54% (n=14) of the food handlers reported that they had received training, none of the food handlers were could provide formal documentation to verify their training. However, there was general consensus (n=26; 100%) that food safety training is important. Despite the evident lack of knowledge regarding refrigeration and holding temperatures for hot ready-to-eat foods, the food handlers agreed that refrigerators/freezers should be checked regularly to reduce the risk of contamination. The microbial analysis study revealed that food contact surfaces, including food handlers’ hands, yielded high counts of all detected microorganisms (TVC, total coliforms, Escherichia coli, Staphylococcus sp., Salmonella sp., and Pseudomonas sp). This indicated a discrepancy between knowledge of food processing and of environmental and personal hygiene. In natural settings, microorganisms can be introduced in various ways by means of people, food, water bioaerosols, and domestic animals. The acquisition of microorganisms such as Stenetrophomonas maltophilia, Sphingomonas paucimobilis, and Myroides odorantum that are predominantly associated with clinical infections was evidence of possible cross-contamination from the hospital wards to the kitchen. The investigation of the extended-spectrum beta-lactamase (ESBL) production of Gram-negative bacteria revealed positive ESBL production in 43% of the microorganisms. This is an important finding given that the ESBL-producing genes can be transferred within niches and the production of these enzymes confers resistance to most commonly used antibiotics. Additionally, there was a 71% multidrug resistance among isolates and none of the microorganisms tested showed susceptibility to current antibiotics. However, a 100% resistance to penicillin was noted which affirms the growing resistance of microorganisms to common antibiotics and the need for new treatment options. The high resistance profile demonstrated by microorganisms in this study can be attributed to personal prescription of antibiotics as these antibiotics are available at pharmacies without a doctor’s prescription. The investigation of the efficacy of the disinfectants against the Gram-negative and Gram-positive bacteria revealed that both disinfectants 1 and 2 exhibited antimicrobial properties against the tested microorganisms. However, disinfectant 2 was found to have bactericidal effect against only the Gram-positive bacteria. The results therefore indicated that although there was an antimicrobial effect of disinfectant 2 against Gram-negative bacteria, disinfecting surfaces with such a disinfectant will not render the surface free from Gram-negative bacteria.