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    Occurrence and molecular characterization of different virulence-associated genes of Cronobacter sakazakii isolates from some foods and dust samples
    (Univ Federal Santa Maria, 2018) Demirci, Ulku; Tekiner, Ismail Hakki; Cakmak, Burcu; Ozpinar, Haydar
    Among the Cronobacter genus, Cronobacter sakazakii is the most common species posing a severe health risk for newborns, infants and children. Some infant formulas, cereal-based foods, and food production environments may be the potential reservoirs of C. sakazakii. This pathogen possesses different virulence factors encoded by different virulence genes. Therefore, characterizing these genes is important for distinguishing pathogenic strains from nonpathogenic ones. The objective of this study was to characterize some virulence genes [OmpA, OmpX, zpx, and Cpa] by real-time polymerase chain reaction (PCR) in C. sakazakii isolates from a total of 120 samples (20 each of milk powder, starch, rice flour, semolina, infant formula and dust samples from food production environments). Overall, 13 isolates (7 from milk powder, 2 rice flour, 1 semolina, and 3 dust) were cultured, identified by bioMerieux API (R) 20E test kit, and then subjected to real-time PCR application for screening the target virulence-associated genes. Our results showed that all of 13 isolates were positive for the virulence genes OmpA, OmpX, zpx, and Cpa. In summary, our study revealed that some of the analyzed foods and environmental samples were contaminated with pathogenic C. sakazakii with its virulence-associated markers, far above the allowable limit; and therefore, this level of contamination may pose a severe health threat for newborns, infants, and children.
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    Phenotypic characterization of ESBL- and AmpC-type beta-lactamases in Enterobacteriaceae from chicken meat and dairy products
    (Ankara Univ, 2017) Ozpinar, Haydar; Tekiner, Ismail Hakki; Sarici, Birsen; Cakmak, Burcu; Gokalp, Fatma; Ozadam, Aylin
    The excess and off-label use of antibiotics results in development of antibiotic resistance among microorganisms. Although microbiological criteria have been appropriately considered in the Food Codex, an inspection for antibiotic-resistant bacteria has not come into force yet. Beta-lactamase producing Enterobacteriaceae adversely affects the human health by leading to therapeutic failures against infections. The objective of this study was to characterize ESBL- and/or AmpC- type beta-lactamases in Enterobacteriaceae isolated from chicken meat, raw milk and unpacked-fresh cheese samples phenotypically. In this study, a total of 327 samples (109 chicken meat, 135 raw milk and 83 unpacked fresh cheese) was examined microbiologically by performing pre-enrichment, enrichment on selective media, and oxidase test according to the Criteria by ISO/DIS21528-2. Overall, 80 ESBL- and/or AmpC positive isolates were identified by mass spectrometer. The most prevalent strain was Escherichia coli (68.8%), followed by Klebsiella pneumoniae (8.8%), Enterobacter cloacae (7.5%), Citrobacter spp. (6.2%), Hafnia alvei (6.2%), and Klebsiella oxytoca (2.5%). The beta-lactamases were screened by disc diffusion, disc diffusion confirmation, and MIC determination according to the Guidelines of Clinical and Laboratory Standards Institute. The most common beta-lactamase type was found as ESBL in 75 isolates, followed by a combination of ESBL & AmpC in 10 isolates, and AmpC in five isolates, respectively. In conclusion, our study showed that ESBL- and/or AmpC-type beta-lactamases were the most common enzymes in Enterobacteriaceae in the analyzed foods.