Distribution and Antimicrobial Resistance Profile of Yersinia Species Isolated From Chicken and Beef Meat

Background: Foodborne diseases are widespread and growing public health problem in developed and developing countries. There are many microorganisms act as etiological agents for foodborne diseases such as Campylobacter spp., Listeria, Staphylococcos, Salmonella, Bacillus, Yersinia spp. High prevalence of gastrointestinal illness, including fatal cases attributable to yersiniosis, is also observed in many developing countries. Objectives: The purpose of this study was to investigate the prevalence of Yersinia enterocolitica and other Yersinia species in meat and chicken samples in various seasons and to determine their antibiotic resistance profile. Materials and Methods: To investigate the prevalence of Yersinia spp., a total of 450 samples, including chicken (n = 226) and beef meat (n = 224) were collected from supermarkets in Tehran. All samples were transported on ice to the laboratory and microbiological analysis was carried out within 2 hours after the collection. Susceptibility testing of bacterial strains was according to CLSI guideline at 28 ̊C by the disk diffusion assay. Results: From a total of 450 samples, (226 chickens and 224 beef meats), 70 (15.5%) samples were positive for Yersinia spp. Of these isolates, (80%) 56 species were identified as Y. enterocolitica, 8 (11%) as Y. frederiksenii, 5 (7%) as Y. intermedia and 1 (1.4%) as Y. kristensenii. The highest rate of resistance was seen against cephalotin (98%), and ampicillin (52%). However, gentamicin and chloramphenicol were the most active antibiotics against the target cultures. Considering the season of isolation, Yersinia spp. were frequently isolated in autumn (52%), followed by spring (29%). Conclusions: Y. enterocolitica was the most spp. distributed among other species. Many factors, such as isolation assay, season, and geographical location play critical role in reports of increase or decrease in the prevalence of the Yersinia spp. all over the world. Our findings demonstrate that the isolation ratio of Y. enterocolitica and other species is higher in colder regions. Most of the isolates were resistant to first generation cephalosporins (cephalothin). The most active antimicrobial agents were choloramphenicol, aminoglycozide and sulfunamdes. Regarding to the high sensitivity of Yersinia spp. to gentamicin and chloramphenicol, these antibiotics would be the choice for the treatment of Yersinia infections.


Background
Foodborne diseases are widespread and growing public health problem in developed and developing countries.There are many microorganisms act as etiological agents for foodborne diseases such as Campylobacter spp., Listeria, Staphylococcos, Salmonella, Bacillus, Yersinia spp.Of these, food contamination with Yersinia species is the frequently reported (1).High prevalence of gastrointestinal illness, including fatal cases attributable to yersiniosis, is also observed in many developing countries (2).The high prevalence of foodborne illnesses acts as a major challenge for the development of food industry and has been one of the major concerns worldwide.Consumption of contaminated poultry and meat can be the main source of contamination (3).Y. enterocolitica is known as a psychotropic waterborne and foodborne enteropathogen.Also, Y. enterocolitica can grow on wide range of temperatures; therefore, food staff contaminated with the bacterium is an important health concern.Yersinia spp. was isolated from various sources like, foods, environment, water and clinical specimens (4).The global increase in chicken and beef meat consumption Int J Enteric Pathog.2015;3(4):e29009 is encouraged by its high protein content and its accessible price has drawn the attention to the necessity of rapid detection of the foodborne pathogens in the chicken and beef meat.Considering the high prevalence of Yersinia spp.infection in human community particularly in developing countries, the present study was carried out to screen raw chicken and beef meat samples collected from retails markets for the presence of Yersinia spp.pathogens.

Objectives
The aim of this study was to evaluate the prevalence of Y. enterocolitica and other Yersinia From raw meat and chicken in Tehran, Iran, in different seasons and to determine the antimicrobial susceptibility pattern of Y. enterocolitica and other Yersinia species obtained from meat and chicken in Tehran, Iran.

Sampling
To investigate the prevalence of Yersinia spp, a total of 450 samples, including chicken (n = 226) and beef meat (n = 224) were collected from Tehran, between April 2013 and April 2014.All samples were transported on ice to the laboratory of the Department of Microbiology, Shahid Beheshti University of Medical Sciences, Tehran and microbiological analysis was carried out within 2 hours after the collection.

Isolation and Identification of Yersinia spp.
In this study, 25 g of meat was homogenized and added to 225 mL of phosphate-buffered saline and incubated at 4˚C.After 2 and 3 weeks, the cold-enriched samples were subjected to alkali treatment by adding 0.5 mL of 0.5% KOH into 4.5 mL of cold-enriched samples.The coldenriched and alkali-treated cultures were streaked onto cefsulodin-irgasan-novobiocin (CIN) agar and incubated at 25˚C for 18 -24 hours.Presumptive Yersinia colonies were identified by biochemical tests using the API 20E (bioMerieux, Inc.US).

Statistical Analysis
Statistical analysis was performed using SPSS software version 11.5 (SPSS, Inc.Chicago, Illinois, USA).The chisquare test and Fisher's exact two-tailed test were used to analyze the data.A P value < 0.05 was used for statistical significance.

Discussion
Yersinia spp. is a Gram-negative rod from the Enterobacteriaceae family.Y. enterocolitica is a common Gramnegative foodborne enteric pathogen found in water, dairy products, and meats.It is one of the most common causes of foodborne gastroenteritis in the entire world and could become a significant health risk for consumers (6,7).These bacteria are highly resistant to unfavorable conditions during food processing, such as low pH, salinity, or disinfectants.In addition, there are considerable problems with detecting pathogenic Y. enterocolitica in food due to the limited sensitivity of the laboratory methods (8).Frequency of Yesinia spp. in various sources such as meat, ground beef, pork, environment, water and human was reported from 9% to 99.5% percent in different regions (9)(10)(11)(12).Our data showed that 15.5% of all studied samples were contaminated with Yersinia spp.and is in constant with other previous local studies in which the rate of contamination have been reported from 13.3% to 16% (13,14).Prevalence of Yersinia spp in Iran is lower than other developing countries (from 32% -38%) (15,16).This may be contributed to isolation method, season, and geographical location.
Our results revealed that Y. enterocolitica was the most predominant Yersinia species recovered from chicken (15%) and meat (9%) which is slightly higher than reports by Siriken (16) in which they found that 8% samples of poultry and 4% samples of beef meat were positive for Y. enterocolitica.The results of our study are in agreement with most of the studies showed that chickens are more vulnerable to contamination with Yesinia spp.However, our result about isolation of Y. enterocolitica was different from studies conducted in Argentina (38.65%),Turkey (27.9%) and Brazil (25%) (15)(16)(17).Frequency of Y. frederiksenii is very diverse from 1.6% to 9% in different countries.In the present study, the prevalence of Y. frederiksenii (11.6%) was similar to other local studies (11%) (14).
According to our results, most of the isolates were resistant to cephalothine (98%) and ampicillin (56%), these results are similar to reports of Soltan-Dallal et al. (18), although in their report most of isolates were sensitive to chloramphenicol and gentamicin.Since the antibiotic profile of isolates in both chicken and meat was similar, it shows that they may share the same sources.
As documented by the results of numerous studies, Yersinia enterocolitica is an important etiological factor in food poisoning (1).Results revealed that a high proportion of chicken and beef meat in Tehran, Iran, is contaminated with Yersinia.The high rate of contamination of meats, particularly chicken, with enteropathogenic bacteria, remains a significant public health concern.Most of the isolates were antimicrobial-resistant; therefore, there is a possible risk to humans to such microorganisms especially from consumption of these products (18).Isolation method, season, and geographical regions are several factors that can play a significant role in reports of increase or decrease in the prevalence of the Yersinia spp.
Y. enterocolitica had the most prevalence among other species.The majority of isolates were resistant to first generation cephalosporins (cephalothine).The most active antimicrobial agents were choloramphenicol and aminoglycozide.Regarding to high Sensitivity of Yersinia spp. to gentamicin and chloramphenicol, these antibiotics would be efficient in the treatment of Yersinia spp.

Table 1 .
Distribution of Yersinia spp. in Chicken and Beef Meat

Table 2 .
Number and Percentages of Antimicrobial Pattern of Yersinia Strains Isolated From Chicken and Beef Meat a,b a I, Intermediate; R, Resistant; S, Sensitive.b The values are peresnted as No. (%).

Table 4 .
Distribution of Yesinia spp. in Different Months of Year a a The values are presented as No. (%).