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Antimicrobial resistance of pathogenic microorganisms is an emerging public health concern. Intensive use of antibiotics in food animals might increase antimicrobial resistance in foodborne pathogens. Colistin is a last resort antibiotic for treatment of multidrug resistant (MDR) Gram negative pathogens. The recent antimicrobial resistance studies revealed a mobile antimicrobial resistance gene (mcr) that provides resistance to colistin. Furthermore, the gene has been found in different genera. Therefore, the aim of this study was to determine colistin resistance of Escherichia coli isolates (N=48) isolated in between 2011 and 2015 from food samples in Turkey. In addition, 5 mcr genes and their variants were screened by performing PCR on resistant isolates. 4 E. coli isolates were found resistant to colistin above the epidemiological cut-off value (Minimum inhibitory concentration (MIC) > 2mg/L). None of the resistant isolates had the mcr genes. Further studies with human and food isolates should be conducted to figure out which gene or genes are responsible for colistin resistance.

Bezelyelerde klorofilin termal degradasyon kinetiği ve görünür yeşil renkteki kayıp 70°, 80°, 90° ve 100 °C’de araştırılmıştır. Klorofil a ve klorofil b’nin parçalanması birinci dereceden bir kinetik model izlemektedir. Tristimulus kolorimetresi ile ölçülen -a, -a/b ve h (hue) değerlerindeki değişim ile ortaya konulan görünür yeşil renkteki kayıp da birinci dereceden reaksiyona uymaktadır. Klorofil a ve b için aktivasyon enerjileri sırasıyla 47.78 and 26.77 kJ mol-1olarak belirlenirken; -a, -a/b ve h değerleri için aktivasyon enerjileri 49.75, 56.04 and 55.06 kJ mol-1 olarak saptanmıştır.

Milk has been the one of the main nutrient sources of human diet for centuries. Microbial studies on milk date back to the seventeenth century, when Kircher used a microscope, and observed the minute worms in milk. Two centuries later, in the1850s, Pasteur proved that the spoilage of milk resulting the sour taste was caused by microorganisms. Pasteur's discoveries on the effect of heat on undesirable microorganisms in beer and wine opened a new era in food science. Therefore, the process was named pasteurization. In the following years of his invention, pasteurization was conducted in Germany and the U.S.A. (Jay, Modern food microbiology. Aspen Publishing, Gaithersburg, MD, 2000). Another breakthrough in milk safety was refrigeration, which became popular after the 1950s. With the advances in heat treatment and low temperature storage, shelf life of pasteurized milk had been increased significantly. Today, pasteurization, partial sterilization, refrigeration, dehydration, and fermentation are commonly used to increase the shelf life of milk and dairy products. Besides these traditional methods, there are also novel methods used to prevent dairy products from spoilage and pathogen contamination such as high pressure processing an UV light. WOS:000431735400012

WOS: 000390071600012 PubMed ID: 27768932 192 Food samples (commonly consumed 8 food types), 355 animal samples (animal feces of bovine, ovine, goat and chicken) and 50 samples from clinical human cases in Sanliurfa city, Turkey in a year were collected to determine the Salmonella enterica subsp. enterica mosaic in Turkey. 161 Salmonella isolates represented 17 serotypes, 20 sequence types (STs) and 44 PFGE patterns (PTs). 3 serotypes, S. Enteritidis, S. Typhimurium and S. Kentucky, were recovered from three different hosts. The highest discriminatory power was obtained by PFGE (SID = 0.945), followed by MLST (SID = 0.902) and serotyping (SID = 0.885) for all isolates. The prevalence of antimicrobial resistance genes (aadA1, aadA2, strA, strB, aphA(1-lab) bla(TEM-1), bla(PSE-1), tetA) was highly correlated with phenotypic profiles of aminoglycoside, beta-lactam and tetracycline groups (kappa >0.85). From our knowledge, this is the first study reporting spatial and temporal distribution of Salmonella species through phenotypic and genetic approaches over farm to fork chain in Turkey. Thus, our data provided further information for evolution, ecology and transmission of Salmonella in Turkey. (C) 2016 Published by Elsevier B.V. Scientific and Technical Council of TurkeyTurkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [TUBITAK 3501(1120192)] We acknowledge Dr. Martin Wiedmann from Cornell University for using BioNumerics, Dr. Nihat Dilsiz from Harran University Medicine Faculty, Harran University Veterinary Faculty for the valuable discussion, and Dr. Tolga Can from Middle East Technical University, Computer Engineering for building a web-based database. This work is partially supported by The Scientific and Technical Council of Turkey Grant TUBITAK 3501(1120192).

Nontyphoidal salmonellosis has been characterized by a pattern of dissemination of clonal Salmonella enterica. The most well-known example of this was S. enterica serovar Typhimurium definitive phage type 104 (DT104), a clone that emerged and disseminated globally in the 1990s (1). Other examples of epidemic clones include Salmonella serovar Wien, which spread from North Africa through Europe in the 1970s; S. Typhimurium phage type 10 (DT10), which disseminated across Canada in the 1970s; and other phage types of S. Typhimurium associated with cattle that disseminated widely in Europe during the 1980s (2). More recently, multidrug-resistant (MDR) S. Agona was disseminated in poultry in Belgium; MDR S. Paratyphi B dT+ in Germany, Belgium, and the Netherlands; and MDR S. Newport that harbors the plasmid-mediated AmpC resistance in the United States (3). Epidemic clones may remain largely restricted to the animal reservoir for years before their incidence rises among human infections: S. Typhimurium phage type 204c disseminated throughout the United Kingdom in cattle from 1980 through 1984, but its proportion among human S. Typhimurium infections was not high during that period (4). Some epidemic clones, for example DT10 and DT104, expanded in the absence of a specific resistance advantage (1). The mechanisms underlying emergence, dissemination, and subsequent decline of novel Salmonella clones are unknown, although some researchers have hypothesized that fitness-associated genetic factors may allow more efficient dissemination in specific hosts and environments (5) and that acquisition of these fitness genes may be phage mediated (6). One approach to understanding clonal replacement events is to conduct prospective surveillance of Salmonella infections in animal and human hosts. We initiated such a study to compare human- and animal-origin Salmonella strains by serovar, antimicrobial drug resistance pattern, and pulsed-field gel electrophoresis (PFGE).

Background The bacterium Salmonella enterica includes a diversity of serotypes that cause disease in humans and different animal species. Some Salmonella serotypes show a broad host range, some are host restricted and exclusively associated with one particular host, and some are associated with one particular host species, but able to cause disease in other host species and are thus considered "host adapted". Five Salmonella genome sequences, representing a broad host range serotype (Typhimurium), two host restricted serotypes (Typhi [two genomes] and Paratyphi) and one host adapted serotype (Choleraesuis) were used to identify core genome genes that show evidence for recombination and positive selection. Results Overall, 3323 orthologous genes were identified in all 5 Salmonella genomes analyzed. Use of four different methods to assess homologous recombination identified 270 genes that showed evidence for recombination with at least one of these methods (false discovery rate [FDR] ompC, a gene encoding an outer membrane protein, which has also been found to be under positive selection in other bacteria. A total of 8, 16, 7, and 5 genes showed evidence for positive selection in Choleraesuis, Typhi, Typhimurium, and Paratyphi branch analyses, respectively. Sequencing and evolutionary analyses of four genes in an additional 42 isolates representing 23 serotypes confirmed branch specific positive selection and recombination patterns. Conclusion Our data show that, among the four serotypes analyzed, (i) less than 10% of Salmonella genes in the core genome show evidence for homologous recombination, (ii) a number of Salmonella genes are under positive selection, including genes that appear to contribute to virulence, and (iii) branch specific positive selection contributes to the evolution of host restricted Salmonella serotypes.