In this study, the presence of Listeria monocytogenes was assessed along the production process of fermented sausages in a small-scale facility. Following the isolation of the pathogen from the final product (ISO 11290-1), retrospective sampling was performed during the production of a new batch of sausages, including raw materials, casings, additives, sausage mixtures, sausages during fermentation, and environmental samples. L. monocytogenes was recovered from the following sampling points: the defrosting room and the cuttering, mixing, stuffing, and fermentation phases. Ten strains were isolated, molecularly confirmed as L. monocytogenes by means of a molecular detection system, and subjected to pulsed-field gel electrophoresis (PFGE) typing. On the basis of an unweighted pair group method with arithmetic mean (UPGMA) dendrogram from Ascl pulsotypes, the strains were indistinguishable (no band difference). The same pulsotypes of strains present in both batches of sausages, as well as in environmental samples, indicated the persistence of L. monocytogenes in the sausage production unit.

Yersinia enterocolitica is one of the priority biological hazards in pork inspection. Persistence of the pathogen, including strains resistant to antimicrobials, should be evaluated in pigs from different housing systems for risk ranking of farms. In this 2019 study, tonsils were collected from 234 pigs, of which 69 (29.5%) were fattened on 3 big integrated farms, 130 (55.5%) on 10 medium-sized farms, and 35 (15%) on 13 small family farms. In addition, 92 pork cuts and minced meat samples from the same farms were tested for the presence of Y. enterocolitica using the culture method. Phenotypic and genetic characteristics of the isolates were compared with previously collected isolates from 2014. The overall prevalence of Y. enterocolitica in pig tonsils was 43% [95% CI 36.7–49.7]. In pigs from big integrated, medium-sized, and small family farms, the prevalence was 29%, 52%, and 40%, respectively. All retail samples of portioned and minced pork tested negative for pathogenic Y. enterocolitica, likely due to high hygienic standards in slaughterhouses/cutting meat or low sensitivity of culture methods in these matrices. The highest recovery rate of the pathogen from tonsils was found when alkali-treated PSB and CIN agar were combined. The biosecurity category of integrated and medium farms did not affect the differences in prevalence of Y. enterocolitica (p > 0.05), in contrast to family farms. Pathogenic ail-positive Y. enterocolitica biotype 4 serotype O:3 persisted in the tonsils of pigs regardless of the type of farm, slaughterhouse, and year of isolation 2014 and 2019. PFGE typing revealed the high genetic concordance (80.6 to 100%) of all the Y. enterocolitica 4/O:3 isolates. A statistically significant higher prevalence of multidrug-resistant Y. enterocolitica 4/O:3 isolates was detected in the tonsils of pigs from big integrated farms compared to the other farm types (p < 0.05), with predominant and increasing resistance to nalidixic acid, chloramphenicol, and streptomycin. This study demonstrated multidrug resistance of the pathogen in pigs likely due to more antimicrobial pressure on big farms, with intriguing resistance to some clinically relevant antimicrobials used in the treatment of yersiniosis in humans.

β-lactamases are a diverse class of enzymes produced by bacteria that present a major cause for resistance to β-lactams. In this study we analysed 159 fecal samples from dairy cows, for the presence of presumptive ESBL, AmpC, and carbapenemase-producing E. coli. Phylotyping was done using Clermont phylo-typing method, targeting arpA, ChuA, and YjaA genes, along with the DNA fragment TspE4.C2. Convetional PCR method was used to confirm the presence of bla genes among 39 phenotypically confirmed ESBL producing E. coli. The results showed presence of CTX-M, SHV, TEM and OXA1 bla genes in 28 (71.79%), 1 (2.56%), 29 (74.35%), 2 (5.12%) of isolates, respectively Twenty (51.28%) isolates showed presence of both blaCTX-M and TEM genes. The strain that carried the blaSHV gene was found to carry blaTEM gene as well, while one of the strains that carried blaOXA1 gene was also carrying blaCTX-M and TEM gene. The ration between isolates and phylo-groups was as follows: 9 (23.07%) strains were assigned to phyllo-group D; 14 (35.89%) to phyllo-group B; 16 (41.02%) to phyllo-group A. Out of the 39 strains where bla genes were identified, 29 (74.35%) were categorized as multi drug resistant.

Commensal Escherichia coli has the potential to easily acquire resistance to a broad range of antimicrobials, making it a reservoir for its transfer to other microorganisms, including pathogens. The aim of this study was to determine the prevalence of resistant commensal Escherichia coli isolated from dairy cows’ feces. Phenotypic resistance profiles and categorization were determined by minimum inhibitory concentration (MIC) testing with the broth microdilution method, while the PCR method was used to determine the presence of resistant genes. Out of 159 commensal E. coli isolates, 39 (24.5%) were confirmed to have resistance. According to the MIC values, 37 (97.3%) and 1 (2.7%) isolate were phenotypically categorized as ESBL and ESBL/AmpC, respectively. All isolates showed resistance to ampicillin, while 97.4%, 56.4%, and 36% showed resistance to cefotaxime, ciprofloxacine, and azitromycine, respectively. Not all isolates that showed phenotypic resistance were found to be carrying the corresponding gene. The most prevalent resistant genes were gyrA, tetA, sul2, and tetB, which were present in 61.5%, 64%, 54%, and 49% of the isolates, respectively. The results clearly indicate that, besides their resistance to multiple antimicrobials, the commensal E. coli isolates did not necessarily carry any genes conferring resistance to that particular antimicrobial.

The present study describes the genetic characterization of L. monocytogenes strains found in the Republic of Kosovo’s food chain. From 2016 to 2022, 995 samples were collected. Overall, 648 samples were from ready-to-eat (RTE) food products, 281 from food products consumed cooked (FPCC), 60 from raw materials, and 6 from environmental samples. Overall, 11.76% (117 out of 995) of the samples were contaminated by L. monocytogenes, comprising 6.33% (41 out of 648) from RTE products, 14.95% (42 out of 281) from FPCC, 55.00% (33 out of 60) from raw materials, and 16.66% (1 out of 6) from environmental samples. All isolates were subjected to molecular serotyping and clonal complex (CC) identification by using real-time PCR, as well as multilocus sequence typing. All isolates were grouped into four molecular serotypes, IIa (34.19%), IIb (3.48%), IIc (32.48%), and IVb (29.91%), as well as Lineage I (33.33%) and Lineage II (66.66%). In total, 14 CCs were identified from 41 RTE isolates; however, CC29 (7), CC2 (6), and CC6 (6) were the most dominant. By contrast, CC9 was by far the most represented CC in both FPCC (21) and RM (14). Moreover, 30 isolates expressed CC1, CC2, CC4, or CC6, which are particularly associated with severe human infections.

The aim of the present study was to evaluate the persistence of Listeria monocytogenes in raw milk from vending machines, based on culture and molecular detection of pathogen and Pulsed-Field Gel Electrophoresis typing. From December 2015 to January 2017, a total of 319 milk samples from 36 vending machines were examined for the presence and count of L. monocytogenes by reference methods ISO 11290:1 and ISO 11290:2. Molecular detection of pathogens was performed by loop-mediated isothermal DNA amplification (LAMP) coupled with bioluminescence (Molecular Detection Assay). L. monocytogenes was detected by MDA in 14 milk samples (4.38%) from four farms, compared to eight positive samples (2.5%) retrieved by a reference ISO method. Cultivable L. monocytogenes isolates were subjected to Pulsed-Field Gel Electrophoresis typing and pulsotypes were compared with those obtained during the previous survey in Croatia (2014‒2015). It was found that identical PFGE patterns of L. monocytogenes occur in milk samples of the same producer over a three-year period, indicating the persistence of pathogens in raw milk vending machines. The results obtained support the need for more effective control of milk in the entire food chain.