A significant risk factor for developing Clostridium difficile infection (CDI) in humans and animals is associated with the antimicrobial use. It has often been hypothesized that farm animals could be the source for human infection with C. difficile (CD). In EU, family-run dairy farms are the predominant farming model. In the present study, a total of 159 CD isolates from 20 family dairy farms were tested with a customized broth microdilution plate for their antimicrobial resistance against 17 selected antimicrobials. Antimicrobials which are used for the treatment of CDI in humans (metronidazole, vancomycin, fusidic acid, tigecycline, linezolid) inhibited in vitro growth of CD. Most CD isolates were resistant to erythromycin (93.1%), daptomycin (69.2%) and clindamycin (46.5%). A high multiple-resistance was found in CD ribotype 012 (n=5; 100%), some CD SLO 060 (n=4; 25%) and one CD 033 (n=1; 1.1%), showing low prevalence (10/159; 6.3%). The high multiple-resistance was associated with ribotypes and not with the origin of CD. The low prevalence of these ribotypes indicates that family-run dairy farms are an unlikely source of CD with multiple-resistance to antimicrobials.
The purpose of the study was to investigate the presence, distribution and dynamics of extended-spectrum beta-lactamases (ESBL) and plasmid-mediated AmpC beta-lactamases (AmpC) producing Escherichia coli in meat-type poultry and their environment. Three broiler breeder flocks, four broiler flocks originating from these breeders, and four meat-type turkey flocks were included in a longitudinal study. A total of 349 samples were tested. All environmental samples collected before placement of birds on the farms were negative for ESBL and AmpC-producing E. coli. However, during the observation period, the ESBL-producing E. coli were detected in 41/186 samples (22.0%), while AmpC-producing isolates were identified in 10.8% of samples. The resistant strains predominantly belonged to E. coli phylogenetic group A1 (36.2%), followed by D1 (24.1%), B1 (22.4%) and D2 (10.3%). The only genes detected were blaSHV-12, blaCMY-2 and blaCTX-M. No significant differences were observed in the rates of detection of resistant strains in feces (18.8%), air samples (31.4%) or organs of dead birds (20.7%), which suggested that air samples can be successfully used as an indicator for the identification of positive flocks in order to prevent or reduce cross contaminations in the slaughter houses.
Antibiotics have always been regarded as miraculous, saving innumerable lives. However, the unwise use of antimicrobial drugs has led to the appearance of resistant bacteria. The purpose of this study was to evaluate the antimicrobial resistance in Escherichia coli (n=160) isolated from food of animal origin, especially of E. coli producing the extended-spectrum beta-lactamases (ESBL). E. coli was selected as being a part of the normal microbiota in mammals and entering the food chain during slaughtering and food manipulation. Subsequently, its resistance genes can be transferred to pathogenic bacteria and human microbiota. Phenotypic and genotypic analyses of the selected antimicrobial resistances were performed together with a molecular analysis of virulence genes. E. coli isolates from food of animal origin were compared with clinical E. coli strains isolated from the human intestinal tract. ESBL-producing E. coli were found in 9.4% of food isolates and 1.8% of intestinal isolates. Phylogenetically, the majority of food (86.3%) and intestinal (58.1%) E. coli isolates were found to belong to the commensal phylogenetic groups A and B1. The distribution of four of 14 analyzed virulence factors was similar in the food and intestinal isolates. Strains isolated from food in Slovenia harbored resistance genes and virulence factors, which can constitute a problem for the food safety if not handled properly.
For almost a decade, the number of Salmonella enterica subspecies enterica serovar Infantis-positive broiler flocks has been steadily increasing in Slovenia. Since multidrug resistant S. Infantis isolates are highly prevalent in the broiler meat industry and may represent a public health concern through the food chain, we investigated the antimicrobial susceptibility, genetic diversity, and biofilm-forming ability of 87 S. Infantis isolates from Slovenian broiler flocks. Only 8.0% of the isolates were susceptible to all of the antimicrobial agents tested, while 88.5% of the isolates were multidrug resistant, with the most common resistance pattern CipNxSSuT. Pulsed-field gel electrophoresis (PFGE) revealed a high genetic homogeneity as a vast majority of the isolates showed )90% PFGE profile similarity. The isolates were grouped into five clusters comprising 16 distinct XbaI PFGE profiles. The majority of isolates (65/87) were grouped in two clusters. The biofilm-forming capacity of the tested isolates was generally weak. The average biofilm formation for persistent strains was higher than for presumably non-persistent strains; however, the difference was not significant. It seems that S. Infantis persistence on broiler farms is more related to its widespread occurrence in the broiler production chain and ineffective disinfection protocols than to its ability to form biofilm.
Salmonella Typhimurium is an important zoonotic pathogen with high levels of antimicrobial resistance. In the present study, we compared the pulsed-field gel electrophoresis (PFGE) and antimicrobial resistance patterns of 275 S. Typhimurium isolates from humans, animals and food, collected between 2000 and 2012. A high rate of antimicrobial resistance was detected (71.6%). Multidrug resistance (MDR) was detected in more than half of the isolates. The proportion of MDR isolates was the highest in animals, followed by food and humans. Among 27 phenotypically determined resistance patterns, three were found to be most common: ACNaSuT, ACSuT and ASuT. The first two patterns were the most prevalent in animal isolates, while ASuT isolates were most commonly obtained from humans. Macrorestriction with XbaI revealed 72 pulsotypes in nine clusters and 19 unique pulsotypes. By far largest cluster included 29 pulsotypes and comprised 58.2% of tested isolates; two thirds of the isolates in this cluster were MDR. This work provided valuable data about resistance and PFGE patterns of S. Typhimurium isolates in Slovenia, which could serve as a base for both national and multistate outbreak investigations.