No abstract

Yersinia enterocolitica and Yersinia pseudotuberculosis strains isolated from wild boars and fattening pigs were characterized and compared with each other. In wild boars, ail-positive Y. enterocolitica strains belonged to bioserotypes 4/O:3 (36%, 5/14), 2/O:9 (29%, 4/14), and 2/O:5,27 (21%, 3/14). Additionally, two ail-positive strains were untypable. Among fattening pigs, the bioserotype 4/O:3 was dominating (91%, 71/78), and bioserotypes 2/O:5,27 (8%, 6/78) and 2/O:9 (1%, 1/78) were rare. Yersinia enterocolitica and Yersinia pseudotuberculosis strains isolated from wild boars and fattening pigs were characterized and compared with each other. In wild boars, ail-positive Y. enterocolitica strains belonged to bioserotypes 4=O:3 (36%, 5=14), 2=O:9 (29%, 4=14), and 2=O:5,27 (21%, 3=14). Additionally, two ail-positive strains were untypable. Among fattening pigs, the bioserotype 4=O:3 was dominating (91%, 71=78), and bioserotypes 2=O:5,27 (8%, 6=78) and 2=O:9 (1%, 1=78) were rare.

Aims:  Yersinia enterocolitica 4/O:3 isolates of slaughter pigs originating from different farms were characterized to study the distribution of different genotypes at farm. A correlation between the genotypes and the resistance patterns was also examined. Methods and Results:  Hundred and eighty‐seven ail‐positive Y. enterocolitica 4/O:3 isolates recovered from pigs originating from 31 Bavarian farms in 2000, 2003 and 2004 were characterized. PFGE using NotI, ApaI and XhoI enzymes revealed 31 genotypes. The most common genotype was found in 13% of the pigs. From most farms (71%), only one genotype was found. Some genotypes were found during different years. Low resistance was noted to streptomycin (9%), sulphamethoxazole (9%), amoxicillin/clavulanic acid (5%) and tetracycline (1%) by agar disc diffusion method. Conclusions:  Several genotypes were found. Some genotypes were widely distributed and persisted for years. Farm‐specific genotypes may exist. No clear relation between the genotypes and antimicrobial patterns was found. Significance and Impact of the Study:  This study provides data on the genetic diversity of Bavarian pig strains and antimicrobial resistance. It may be of interest for other countries where Y. enterocolitica strains are genotyped to get more information about the strain distribution of this pathogen.

One hundred eighty-six strains of enteropathogenic Yersinia (Y.) enterocolitica of bioserotypes 2/O:5,27, 2/O:9, 3/O:3, and 4/O:3 and 12 strains of Yersinia pseudotuberculosis of bioserotypes 1/O:1, 1/O:2, and 2/O:1 from different human (feces) and nonhuman (pig, pork, wild boar, monkey, chinchilla, mara, capybara, salad) sources collected in the years 1995-2009 were examined. Antimicrobial resistance patterns for 12 antimicrobial agents were generated using broth microdilution. The presence and characterization of the β-lactamase genes blaA and blaB were studied using polymerase chain reaction (PCR) and PCR-restriction fragment length polymorphism (RFLP), respectively. The expression of β-lactamase BlaA and BlaB was detected using double-disc diffusion. Y. enterocolitica strains showed resistance to ampicillin (92%), streptomycin (13%), and sulfamethoxazole (2%). Intermediate susceptibility to tetracycline was shown by two Y. enterocolitica strains. All Y. pseudotuberculosis strains were susceptible to all tested antimicrobial agents. Most (99%) of the Y. enterocolitica strains carried both β-lactamase genes. One strain of bioserotype 3/O:3 lacked both genes. In contrast, all Y. pseudotuberculosis strains carried neither of the β-lactamase genes. Homogeneity was detected in all blaA and blaB genes of Y. enterocolitica using PCR-RFLP. The majority (89%) of Y. enterocolitica strains expressed both β-lactamase enzymes, whereas none of the Y. pseudotuberculosis strains showed expression of either enzyme. Also, it seems that the resistance of Y. enterocolitica has not changed during the last years.

Since 1989, blown pack spoilage has been recognized as a special form of spoilage in vacuum-packed raw and cooked beef. However, only limited information concerning the occurrences of bacteria causing blown pack spoilage on chilled fresh meat is available. In this study, a total of 63 beef and 33 lamb commercially available samples from different countries and without any signs of spoilage were examined for contamination with psychrophilic and psychrotolerant Clostridium spp. using different PCR systems. In total, 34.4% of the chilled fresh vacuum-packed meats were PCR positive. A higher number of lamb samples were identified as PCR positive compared with beef. A geographical relationship between positive results and the origin of the samples could not be determined. PCR system described by Brightwell and Clemens (Development and validation of a real-time PCR assay specific for Clostridium estertheticum and C. estertheticum-like psychrotolerant bacteria. Meat Sci 2012;92:697-703) gave the highest number of positive detections compared with the Broda, Boerema and Bell PCR system (PCR detection of psychrophilic Clostridium spp. causing 'blown pack' spoilage of vacuum-packed chilled meats. J Appl Microbiol 2003;94:515-22). Eight clostridia isolates from two German beef and four Welsh lamb samples were isolated overall. Three of these clostridia isolates were identified as Clostridium estertheticum whereas five clostridia isolates remain unidentified. The study shows that psychrophilic and psychrotolerant Clostridium spp. are more prevalent in retail samples than previously suspected.