Assessment of the Bacterial Contamination beneath Fingernails of Food Handlers in a General Hospital
Introduction
Hands play a major role in the transmission of infection in healthcare institutions(1); the importance of hand hygiene in the control of infection cannot be underemphasized(2). The subungual region contains large numbers of bacteria which are largely inaccessible during hand hygiene practices and are therefore difficult to clean compared with the rest of the hands. Longer nails have increased numbers of microorganisms(3), therefore food handlers are best advised to keep their nails trimmed to less than 2 mm beyond the fingertips(4).
The microbial population of the skin is divided into resident flora and transient flora. The resident flora are associated with the deeper layers of the skin such as the sebaceous glands and these organisms are inaccessible to hand hygiene preparations. The resident flora rarely cause infection unless the skin is breached by a device. The transient flora colonize the superficial layers of the skin and are less adherent. They are more easily removed by hand washing and may be transferred by direct hand contact. The transient flora include microorganisms which are frequently associated with nosocomial infection(5,6).
Medical institutions are supposed to provide a model for healthy practices for the society, therefore, it is expected that their food service establishments and the food handlers working there should not act as sources of foodborne diseases(7). In the present study, we aimed to determine the bacterial contamination under the finger nails of the personnel working in food handling at the kitchens of Kasr El Ainy hospitals. The carriers were identified and guided for the appropriate treatment according to the results of culture and sensitivity done for each person (with the approval and coordination of the hospital management). The present study was approved by the dermatology research ethical committee (DermaRec) of the faculty of medicine, Cairo University.
Subjects and Methods
Subjects
We performed a descriptive non analytical study, sixty food handlers, working at the kitchens and catering department operating within the premises of Kasr El Aini hospitals, Cairo University were included in the study.
Information collected included demographic and professional characteristics such as age, gender, nature of job, duration in the profession, habits of wearing gloves, history of disease if any (recall period of 1 month) and healthcare sought for it.
Methods
Nail samples were obtained from bare hands of food handlers during working hours. Nail clippings obtained from the thumb, index and middle fingers of both hands were collected from each individual using a separate pair of scissors. Clipped nails were transported in a dry, sterile container, and embedded into a set of culture plates containing: Blood agar, MacConkey’s agar, and Salmonella Shigella (SS) agar media for each hand. Incubation was done in ambient air at 37°C for 24 hours. Duplicate cultures were done representing left and right hands of each subject.
Isolated colonies were identified according to their lactose fermentation reaction on MacConkey’s and SS agar (along with H2S production), in conjunction with microscopic morphology and hemolytic reaction on blood agar. Confirmation was done using Microbact 12A panel for biochemical reactions of enteric Gram-negative bacilli, utilizing an octal coding system that is interpreted by a computerized software package.
Statistical analysis
Data were coded, entered and analyzed using SPSS software package for statistical science (Version 10.0), including descriptive analysis as mean value and standard deviation (SD) using paired sample T-test.
Results
The present study included 19 females (31.7%) and 41 males (68.3%). The mean age of subjects was 42.2 ± 9.979 years. The mean duration of occupation was 13.95 ± 10.09 years. 45 subjects (75%) had no complaint, while 8 subjects (13.3%) complained of abdominal pain and 7 (11.7%) complained of fever. 40 subjects (66.7%) used gloves regularly, while 20 subjects (33.3%) documented irregular use of gloves. Based on the nature of the work they were engaged in for the majority of their working hours, study subjects were classified as cookers (n=20, 33.3%), food deliverers (n=32, 53.4%), food processors (n=4, 6.7%), dishwashers (n=2, 3.3%), and supervisors (n=2, 3.3%).
In the present study, 14 types of bacteria were isolated from the nails of the studied group. 100% of the study subjects were determined to carry bacteria in the subungual region, with each harboring 1-2 bacterial species.
The type and percentage of bacterial species isolated from study subjects is shown in Table (1).
The distribution of different types of bacteria detected among different working groups is shown in Table (2).
Table 1. Type and percentage of bacterial species isolated from study subjects
|
Bacteria |
No. of positive subjects |
% |
|
Staphylococcus epidermidis |
10 |
19.6 |
|
E. coli |
8 |
15.6 |
|
Staphylococcus aureus |
8 |
15.6 |
|
Klebsiella oxytoca |
6 |
11.7 |
|
Salmonella |
4 |
7.8 |
|
Pseudomonas aeruginosa |
4 |
7.8 |
|
Acinetobacter baumanii |
4 |
7.8` |
|
Enterobacteraciae gergoviae |
3 |
5.8 |
|
Sternotrophomonas |
3 |
5.8 |
|
Citrobacter frundii |
3 |
5.8 |
|
Enterobacter cloacae |
2 |
3.9 |
|
Klebsiella pneumonia |
1 |
1.9 |
|
Serratia liquifaciens |
1 |
1.9 |
|
Citrobacter diversus |
1 |
1.9 |
Table 2. Distribution of Bacteria among Different Working Groups
|
Other bacteria |
Cookers (n=20) |
Food deliverers (n=32) |
Food processors (n=4) |
Dish washers (n=2) |
Supervisors (n=2) |
|
Staphylococcus epidermidis |
3 (15%) |
5 (15.6%) |
- |
1 (50%) |
1 (50%) |
|
E. coli |
3 (15%) |
4 (12.5%) |
1 (25%) |
- |
- |
|
Staphylococcus aureus |
2 (10%) |
5 (15.6%) |
- |
- |
1 (50%) |
|
Klebsiella oxytoca |
3 (15%) |
3 (9.3%) |
- |
- |
- |
|
Salmonella |
1 (5%) |
2 (6.25%) |
1 (25%) |
- |
- |
|
Pseudomonas aeruginosa |
1 (5%) |
2 (6.25%) |
- |
1 (50%) |
- |
|
Acinetobacter baumanii |
2 (10%) |
2 (6.25%) |
- |
- |
- |
|
Enterobacter gergoviae |
2 (10%) |
1 (3.1%) |
- |
- |
- |
|
Stenotrophomonas |
- |
2 (6.25%) |
1 (25%) |
- |
- |
|
Citrobacter frundii |
1 (5%) |
1 (3.1%) |
- |
1 (50%) |
- |
|
Enterobacter cloacae |
1 (5%) |
1 (3.1%) |
- |
- |
- |
|
Klebsiella pneumonia |
- |
1 (3.1%) |
- |
- |
- |
|
Serratia liquifaciens |
1 (5%) |
- |
- |
- |
- |
|
Citrobacter diversus |
- |
1 (3.1%) |
- |
- |
- |
Fig. 1. Distribution of different types of bacteria in food handlers
Discussion
Our study was conducted on 60 subjects working in the field of food handling in a university hospital. The workers were divided into five working groups according to the nature of their work.
The most common bacteria isolated from the hands were Staphylococcus epidermides (S. epidermides) (10/60, 19.6%), S. aureus and Escherichia coli (E. coli) (8/60, 15.6%) each. The rather high isolation rates of S. aureus and S. epidermides from the hands, with respect to other microorganisms can be explained by the fact that these organisms are found in the permanent flora of the skin. Approximately 35-40% of the healthy adults carry S. aureus asymptomatically(8,9). The loads of S. aureus in the hands are alarming especially since finished meals are handled by these highly contaminated hands(10).
Escherichia coli (E. coli) is a bacterium found in the intestinal tract of humans and only some lines are considered pathogenic to man. These are divided into five categories based on virulence, clinical syndromes and differences in epidemiology or in serotypes(11). Food implicated in EHEC outbreaks includes ground beef, meat, and poultry, sea food and apple juice(12). E. coli is an important cause of food poisoning(10). The isolation of E. coli from the hands emphasizes an important fecal contamination, and indicates that food handlers are not taking enough care in hand hygiene.
Salmonella is gram negative facultative anaerobes from the family Enterobacterceae(13). Infection is associated primarily with unhygienic conditions and improper handling and cooking of food items(14). Salmonella have been associated with raw meat, poultry, eggs, and dairy products(15).
This could explain why we detected the greater affection by E. coli and Salmonella in food processors responsible for handling raw meat. E. coli was found in 25% of food processing group, in 15% of cookers and in 12.5% in food deliverers. On the other hand, Salmonella was commoner in food processing group (25%) followed by food deliverers (6.25%) followed by cookers (5%). Other bacteria were distributed among different groups with food deliverers being the commonest followed by the cookers.
In the present study, 66.7% of food handlers used gloves during working hours. However, some of these subjects reported not washing hands before putting on gloves, and others did not change gloves before doing a new task. It was recommended that single-use gloves should be used for only one task such as working with ready-to-eat foods or with raw animal food, and should be discarded when damaged or soiled. It was also demonstrated that if individuals do not wash their hands before putting on gloves, both the interior and exterior surfaces of the gloves become contaminated with surface microorganisms on the hands(16,17). As a consequence, training on proper hand washing and glove use should be improved.
In the present study, it was observed that food deliverers and food processors were simultaneously involved in cleaning wards and toilets in the hospital, with the possibilities of contamination. This could partially explain the high distribution of E. coli and Salmonella among food processors followed by food deliverers.
In the era of Quality Programs being implemented by the Ministry of High Education, job description for every person working in university hospitals should be specifically stated and workers should be restricted from doing multiple jobs. This necessitates employing workers for dealing with food only and not doing other jobs. Food handlers in University Hospitals should be well trained and strict hygienic conditions should be implemented. Specific programs should be done for educating food handlers on proper hand washing and following strict hygienic conditions before dealing with food.
The Codex Alimentarius(18) states that all individuals coming into direct or indirect contact with food must be qualified and must recognize their role and responsibility in protecting food against contamination and deterioration. It further determines that every food producing area should provide a training program that is revised and updated whenever needed. Training has to include measures to avoid food contamination, the development and growth of microorganisms, notions about good handling practices and personal hygiene, proper hygienization of food, utensils and the environment, among others, to ensure that food handlers are kept informed of the required procedures for preserving the quality of the food produced.
To our knowledge, this is the first study conducted on food handlers in a university hospital in Egypt. Further studies on a larger scale involving other University Hospitals are recommended. Food handlers should be well trained for proper hand washing and improvement of current programs should be sought.
Acknowledgments
We greatly thank all personnel who were willing to cooperate in this study. We also thank the hospital management who helped us to perform this study.
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