Detection of enterotoxin genes of Staphylococcus SP isolated from nasal cavities and hands of food handlers

Inhibition of histamine accumulation by novel histamine-degrading species of Staphylococcus sp. isolated from goats and sheep milk

Histamine is an active amine compound that occurs in various fermented foods that may cause adverse effects on the human health. Certain microorganisms are able to degrade histamine by an oxidative deamination reaction. Therefore, the present study aimed to quantify histamine-forming and/or -degrading activity of the isolates derived from milk of goat and sheep herds, in Iran, by the capillary zone electrophoresis (CZE) method; and we evaluated the molecular characteristics of staphylococcal isolates. Among 243 staphylococcal isolates, 29 histamine-degrading bacteria were identified. One of these isolates, identified as Staph. epidermidis, No. 605, exhibited the highest activity compared to others, degrading available histamine to 58.33% within 24 h. By polymerase chain reaction (PCR) analysis, the isolate, No. 605 that exhibited remarkable histamine-degrading activity lacked the genes encoding coagulase and DNase, nor did it harbor any of the five classical enterotoxin genes. This is the first report to show that seven Staphylococcus species, including Staph. chromogenes, Staph. aureus, Staph. haemolyticus, Staph. epidermidis, Staph. pseudintermedius, Staph. agnetis, and Staph. hyicus, were able to degrade histamine, which were hitherto not known to have this capacity. Therefore, histamine-degrading activity is a definite criterion to introduce fermenting organisms able to decrease histamine content in different food products.

Food handling practices and associated factors among food handlers working in public food and drink service establishments in Woldia town, Northeast Ethiopia

INTRODUCTION

foodborne disease (FBD) is a major public health problem globally. Inadequate food workers' knowledge, attitude, and low level of food handling practices (FHPs) may all contribute to the possibility of FBD outbreaks in public food service establishments. This study aimed to assess FHPs and associated factors among food handlers working in public food and drink service establishments in Woldia town, Northeast Ethiopia.

METHODS

an institutional-based cross-sectional study was conducted from 01 to 29, January 2017. A total of 288 food handlers were recruited through a simple random selection method. A structured interviewer-administered questionnaire and observation checklists were used to collect the respondents' socio-demographic characteristics, knowledge status on FHPs, and food handling working practices data. Descriptive statistics, bivariate and multivariate logistic regression analysis were employed using SPSS version 20 software. Those variables with a p< 0.05 were considered statistically significant.

RESULTS

out of 288 participants, 91.7% were female, and 82.3% were single, while 69.8% were literate. One hundred eighty-four (63.9%) of them were under 15-25 years of age, with a median age of 23.3 years. The proportion of good FHP was (n=134, 46.5%) (95% CI: 41.00-52.4%). Advanced age (adjusted odds ratio (AOR) =12.01, 95% CI: 1.96-73.52), education (participants who attend grades 7-12 (AOR=2.33, 95% CI: 1.14-4.79), and above secondary education (AOR=2.29, 95% CI: 1.05-4.61), work experience above six years (AOR=2.43, 95% CI: 2.08-3.17), received formal training (AOR=1.79, 95% CI: 1.68-4.71), and inspection visits by a concerned body (AOR=2.24, 95% CI: 1.05-3.09) were factors positively associated with handling practices.

CONCLUSION

the study revealed that FHP in the study area was low. Age, education, service year, training received and sanitary inspection visits by the regulatory personnel were factors significantly associated with FHPs. This finding highlights the importance of employing regular sanitary inspection visits to public food service establishments by the concerned authority to ensure that all food handlers have the knowledge and the skill to provide safe food.

Ecology and Genetic Lineages of Nasal Staphylococcus aureus and MRSA Carriage in Healthy Persons with or without Animal-Related Occupational Risks of Colonization: A Review of Global Reports

In this conceptual review, we thoroughly searched for appropriate English articles on nasal staphylococci carriage among healthy people with no reported risk of colonization (Group A), food handlers (Group B), veterinarians (Group C), and livestock farmers (Group D) published between 2000 and 2021. Random-effects analyses of proportions were performed to determine the pooled prevalence of S. aureus, MRSA, MRSA-CC398, and MSSA-CC398, as well as the prevalence of PVL-positive S. aureus from all eligible studies. A total of 166 eligible papers were evaluated for Groups A/B/C/D (n = 58/31/26/51). The pooled prevalence of S. aureus and MRSA in healthy humans of Groups A to D were 15.9, 7.8, 34.9, and 27.1%, and 0.8, 0.9, 8.6, and 13.5%, respectively. The pooled prevalence of MRSA-CC398 nasal carriage among healthy humans was as follows: Group A/B (<0.05%), Group C (1.4%), Group D (5.4%); and the following among Group D: pig farmers (8.4%) and dairy farmers (4.7%). The pooled prevalence of CC398 lineage among the MSSA and MRSA isolates from studies of the four groups were Group A (2.9 and 6.9%), B (1.5 and 0.0%), C (47.6% in MRSA), and D (11.5 and 58.8%). Moreover, MSSA-CC398 isolates of Groups A and B were mostly of spa-t571 (animal-independent clade), while those of Groups C and D were spa-t011 and t034. The MRSA-CC398 was predominately of t011 and t034 in all the groups (with few other spa-types, livestock-associated clades). The pooled prevalence of MSSA and MRSA isolates carrying the PVL encoding genes were 11.5 and 9.6% (ranges: 0.0-76.9 and 0.0-28.6%), respectively. Moreover, one PVL-positive MSSA-t011-CC398 isolate was detected in Group A. Contact with livestock and veterinary practice seems to increase the risk of carrying MRSA-CC398, but not in food handlers. Thus, this emphasizes the need for integrated molecular epidemiology of zoonotic staphylococci.

Prevalence of Staphylococcus aureus methicillin-sensitive and methicillin-resistant nasal carriage in food handlers in Lebanon: a potential source of transmission of virulent strains in the community

Purpose

To determine the prevalence and virulence determinant genes of nasal colonization by Staphylococcus aureus among food handlers in Tripoli, Lebanon.

Methodology

Within a cross-sectional study design, nasal swab specimens were collected. Epidemiological and microbiological investigations were performed through conventional culture and MALDI-TOF-MS. Antibiotic susceptibility patterns and genetic virulence determinants including enterotoxin genes were also investigated for all isolates.

Results

The data herein show that S. aureus nasal carriage is highly prevalent (23.8 %), and that the rate of methicillin-resistant S. aureus (MRSA) carriage was twice as high as in our last report in 2008. Several enterotoxin genes were detected in five isolates including one MRSA and four methicillin-sensitive S. aureus.

Conclusion

To our knowledge, this is the first investigation in the last decade to examine the carriage prevalence of S. aureus among food handlers in Lebanon. This work reports a concerning level of MRSA, and enterotoxin-producing S. aureus nasal carriage, which could potentially act as a contamination reservoir and lead to food poisoning.

High prevalence of methicillin resistant and enterotoxin gene-positive Staphylococcus aureus among nasally colonized food handlers in central Iran

This study defined the prevalence of enterotoxin gene-positive Staphylococcus aureus strains among food handlers and non-food processing healthy nasal S. aureus carriers in central Iran. Meticillin-resistant S. aureus (MRSA) strains were diagnosed by cefoxitin disk diffusion. PCR was used to detect the mecA, Sa442, and enterotoxin genes. Out of the 1113 food handlers, 224 (20.1%) were nasal carriers of S. aureus and 157 (70.1%) of these isolates were positive for one or more enterotoxin genes. The most prevalent enterotoxin gene was sei (40.2%), followed by seg (35.3%), sea (23.5%), seb (15.2%), sec (5.5%), and seh (2.7%). See and sed genes were not found. Sixty seven (42.7%) of enterotoxin gene-positive isolates possessed a single enterotoxin gene, and 64 (40.8%), 23 (14.7%), and 3 (1.9%) contained two, three, or four enterotoxin genes, respectively. The most frequently detected gene combination was sei/seg (n = 35, 22.3%). Thirty seven (16.5%) isolates were diagnosed as MRSA, and 27 (73%) of these strains were positive for at least one enterotoxin gene. Out of 546 healthy controls, 100 individuals were identified as S. aureus nasal carriers; among the strains, 39 (39%) were positive for at least one enterotoxin gene. Only one (1%) CA-MRSA was identified among the strains from the volunteers. A high prevalence of meticillin resistant and enterotoxin-positive S. aureus were documented in food handlers. We suggest that this may be due to the frequent handling of contaminated foodstuffs and that this is possibly related to the elevated frequencies of acquired staphylococcal food poisoning in this population.

Sanitary quality, occurrence and identification of Staphylococcus sp. in food services

Sanitary conditions are essential for the production of meals and control of the presence of pathogensis important to guarantee the health of customers. The aim of this study was to evaluate the sanitary quality of food services by checking the presence of thermotolerant coliforms, Staphylococcus sp. and evaluate the toxigenic potential from the latter. The analysis was performed on water, surfaces, equipment, ready-to-eat foods, hands and nasal cavity of handlers in seven food services. The water used in food services proved to be suitable for the production of meals. Most food, equipment and surfaces showed poor sanitary conditions due to the presence of thermotolerant coliforms (60.6%). Twenty-six Staphylococcus species were identified from the 121 Staphylococcus isolates tested. Staphylococci coagulase-negative species were predominant in the foods, equipment and surfaces. In food handlers and foods, the predominant species was Staphylococcus epidermidis. Twelve different genotypes were found after PCR for the classical enterotoxin genes. The seb gene (19.8%) was the most prevalent among all Staphylococcus sp. Both coagulase-positive and coagulase-negative Staphylococci showed some of the genes of the enterotoxins tested. We conclude that there are hygienic and sanitary deficiencies in the food services analyzed. Although coagulase-positive Staphylococci have not been present in foods there is a wide dispersion of enterotoxigenic coagulase-negative Staphylococci in the environment and in the foods analyzed, indicating a risk to consumer health.