Prevalence and antimicrobial resistance profiles of Salmonella serotypes, Campylobacter and Yersinia spp. isolated from retail chicken and beef, Tehran, Iran

Prevalence and detection of antibiotic-resistant determinant in Salmonella isolated from food-producing animals

Salmonella spp. infections are considered as the most common food-borne disease globally. The contamination of food products with Salmonella has given rise to severe health and economic challenges. This study assessed the prevalence of Salmonella in the faeces of cows and goats in the Eastern Cape province of South Africa, their antibiotic resistance patterns as well as antibiotic-resistant gene determinant. Antibiotic disc was used for antibiogram profiles while polymerase chain reaction was employed for the detection of antibiotic-resistant genes. A total of 150 Salmonella were isolated from the faecal samples. Eighty two (55%) isolates were recovered from cow faeces while 68 (45%) were isolated from goat faeces. All Salmonella isolates were sensitive to ciprofloxacin (100%) while 95% were sensitive to ofloxacin. Also, a high sensitivity of 93 and 89% was observed against nalidixic acid and ofloxacin, respectively. Salmonella isolates demonstrated moderate sensitivity against cephalothin (70%), chloramphenicol (75%) and minocycline (68%) while 49% were resistant to tetracycline and erythromycin. The prevalence of the antibiotic-resistant genes in Salmonella isolates were detected as follows: integron conserved segment 28% (42/150), bla TEM gene 19.3% (29/150), blapse₁ 7.3% (11/150) and blaampC 4.7% (7/150). The results obtained in the study imply that cow and goat faeces could be potential reservoirs of Salmonella and could possibly cause infections as a result of contamination of food products. There is a need for a surveillance system to track resistance patterns of Salmonella circulating in South Africa.

Prevalence and antimicrobial resistance of Listeria, Salmonella, and Yersinia species isolates in ducks and geese

The aims of this study were to determine the prevalence and antimicrobial resistance of Listeria, Salmonella, and Yersinia spp. isolated from duck and goose intestinal contents. A total of 471 samples, including 291 duck and 180 goose intestinal contents, were purchased from wet markets between November 2008 and July 2010. Listeria, Salmonella, and Yersinia spp. were isolated from 58 (12.3%), 107 (22.7%), and 80 (17%) of the samples, respectively. It was concluded that Listeria ivanovii, Salmonella Thompson, and Yersinia enterocolitica were the predominant serovars among Listeria, Salmonella, and Yersinia spp., respectively. Moreover, resistance to tetracycline was common in Listeria (48.3%) and Salmonella spp. (63.6%), whereas 51.3% of the Yersinia spp. isolates were resistant to cephalothin. Therefore, continued surveillance of the prevalence of the pathogens and also of emerging antibiotic resistance is needed to render possible the recognition of foods that may represent risks and also ensure the effective treatment of listeriosis, salmonellosis, and yersiniosis.

Prevalence and quantitative detection of Salmonella in retail raw chicken in Shaanxi, China

Quantitative Salmonella concentrations and prevalence of Salmonella in raw chicken at the retail level in Shaanxi province, China, was determined in this study. Two hundred forty samples were collected in Yangling and the surrounding cities, in Shaanxi Province, China, for data collection over 12 successive months from April 2011 to March 2012. During the whole surveillance year, the overall Salmonella contamination rate of retail raw chicken was identified as 43.3%, the most-probable-number (MPN) values ranged from 0.0036 to 0.8596 MPN per g, and the average value was 0.1655 MPN per g, except in 11 of the samples, which had MPN values of more than 11 MPN per g. In April 2011, the highest prevalence rate, which was 80.0%, was observed, and the corresponding MPN value was 0.8596 MPN per g. Observed in November 2011, the lowest prevalence rate and the corresponding MPN value were 5.0% and 0.0036 MPN per g, respectively. Prevalence of Salmonella in chicken collected from the supermarket (49.2%) was higher but not significantly different from that in the wet markets (37.5%), although the MPN value of samples in the wet market (0.1912 MPN per g) was higher than that in the supermarket (0.1396 MPN per g). Prevalence of Salmonella was the highest in the frozen chicken (53.3%) compared with chilled chicken (45.0%) and freshly slaughtered chicken (37.5%); however, the MPN value of the freshly slaughtered chicken (0.1912 MPN per g) was higher than those of either frozen chicken (0.1804 MPN per g) or the chilled chicken (0.0988 MPN per g).

Antimicrobial resistance of emerging foodborne pathogens: status quo and global trends

Emerging foodborne pathogens are challenging subjects of food microbiology with their antibiotic resistance and their impact on public health. Campylobacter jejuni, Salmonella spp. and Verotoxigenic Escherichia coli (VTEC) are significant emerging food pathogens, globally. The decrease in supply and increase in demand lead developed countries to produce animal products with a higher efficiency. The massive production has caused the increase of the significant foodborne diseases. The strict control of food starting from farm to fork has been held by different regulations. Official measures have been applied to combat these pathogens. In 2005 EU declared that, an EU-wide ban on the use of antibiotics as growth promoters in animal feed would be applied on 1 January 2006. The ban is the final step in the phasing out of antibiotics used for non-medical purposes. It is a part of the Commission's strategy to tackle the emergence of bacteria and other microbes resistant to antibiotics, due to their overexploitation or misuse. As the awareness raises more countries banned application of antibiotics as growth promoter, but the resistance of the emerging foodborne pathogens do not represent decrease. Currently, the main concern of food safety is counter measures against resistant bugs.

Detection, semiquantitative enumeration, and antimicrobial susceptibility of Yersinia enterocolitica in pork and chicken meats in Italy

Yersinia enterocolitica is recognized as an etiological agent of gastroenteritis, lymphadenitis, and chronic sequelae. During 2006 and 2007, 205 samples (125 pork and 80 chicken meats) were collected in Italy and tested for detection and most-probable-number (MPN) enumeration of Y. enterocolitica organisms. The microorganism was isolated from 45 samples (21.9%): 19 (15.2%) pork samples and 26 (32.5%) chicken samples. Y. enterocolitica MPN contamination levels were low, ranging from 0.30 to 1.50/g. Most (94.4%) Y. enterocolitica strains were biotype 1A (serotypes O:3; O:5; O:6,30; O:6,30-6,31; O:7,8-8-8,19; O:8; O:9; O:25,35; O:36; and O nontypeable), and 5.6% of the isolates were bioserotype 2/O:9. All isolates were tested for yadA, ail, inv, ystA, and ystB virulence sequences. The yadA gene was detected in two strains (3.7%) isolated from chicken samples: one Y. enterocolitica 2/O:9 yadA+ ail+ ystA+, and one Y. enterocolitica 1A/O:7,8-8-8,19 yadA+ inv+ ystB+. Two (3.7%) 2/O:9 strains, isolated from pork products, were ail+ ystA+. Most biotype 1A strains were ystB+ (84.3%) and inv+ (39.2%). All strains were sensitive to cefotaxime, ciprofloxacin, chloramphenicol, nalidixic acid, streptomycin, sulfonamide, tetracycline, trimethoprim, and trimethoprim-sulfamethoxazole. Resistance to gentamicin and aztreonam was observed in 1.9% of the isolates. High levels of resistance were detected toward amoxicillin-clavulanic acid (27.8%), ampicillin (75.9%), and erythromycin (100%). The authors hypothesize that Y. enterocolitica pathogenic biotypes are rather uncommon in foods when compared with their isolation rates from animal sources and that chicken meat could be contaminated as well as pig meat and its derived products.