Transmission And Evolution Of Salmonella

Salmonella, a Gram-negative enterobacterium, is a human and animal pathogen. The species Salmonella enterica includes serotypes with broad and restricted host ranges. The objectives of this study were to utilize genotypic and phenotypic methods to (i) understand Salmonella diversity among human and animal hosts at the population level, and (ii) understand Salmonella genome evolution including the mechanisms of diversity and their contributions to new serotypes. To understand genotypic and phenotypic diversity in Salmonella among human and animal hosts, we used serotyping, multilocus sequence typing (MLST) and pulsed field gel electrophoresis (PFGE) subtyping methods. We found that while some subtypes might have represented host adapted strains within the same serotype, some subtypes were widely distributed among human and cattle isolates. We concluded that isolation of common PFGE types among humans and foods or farm animals must be interpreted carefully and that the establishment of causal relationships will require strong epidemiological linkages and/or the use of additional, more sensitive, subtyping methods. To understand which mechanisms are responsible for diversity in the Salmonella genome, we used 5 whole genome sequences representing four serotypes, Typhi, Paratyphi A, Choleraesuis, and Typhimurium, to identify genes with evidence of positive selection and recombination. Positive selection was detected using PAML 3.15. Intragenic recombination was assessed by four different approaches: GENCONV, Max-chi-2, NSS, and PHI. We found that genes having evidence of recombination may be more likely to be under positive selection. Positive selection may contribute to fixation of new allelic variants generated by recombination. To understand how new Salmonella serotypes emerge, we characterized an emerging serotype, Salmonella 4,5,12:i:-, which is closely related to Typhimurium but lacks the expression of second phase flagellar antigen. We characterized Salmonella 4,5,12:i:- and Salmonella Typhimurium isolates from various sources using MLST, PFGE and PCR screening for differences in presence or absence of genes or intergenic regions. We found that while the majority of 4,5,12:i:- and Typhimurium isolates represented a single MLST type, all 4,5,12:i:- lacked fljA and fljB, which were present in all Typhimurium isolates. PCR screens further showed differences in deletion genotypes among 4,5,12:i:- strains which suggests that Salmonella 4,5,12:i:- appears to represent two different emergence events, both from a serotype Typhimurium ancestor. Overall, my research gives us insight into the evolution of Salmonella that allows us to better understand the transmission and the evolution of Salmonella and its ability to cause disease in different host species. Consequently, we will be able to track contamination sources using much more specific subtyping methods in order to eliminate Salmonella from food products

DETERMINING THE EFFECTS OF THE STINGING NETTLE (URTICA DIOICA) EXTRACT ON BIOFILM FORMATION OF SALMONELLA ENTERICA SEROVARS

The increasing population leads ti an increasing demand for fresh produce all around the world. Making provisions for inhibiting foodborne pathogens, especially the ones producing biofilms, such as Salmonella spp., might remain impossible during the process, due to the cross-contaminations. Thus, foodborne outbreaks can be accompanied by biofilms. Chemical disinfectants are not efficient in disintegrating the biofilms since they cannot penetrate into the biofilm matrix. At this point, plant extracts with correct exposure time on fresh produce are crucial to take timely precautions against the attachment of bacteria to fresh produce. The effects of the water-soluble extract of stinging nettle were determined for biofilm formation capabilities on food product and in vitro, and swimming motilities and curli expressions of Salmonella enterica Virchow, Newport, Typhimurium, Enteritidis, Othmarschen and Mikawasima serovars. Moreover, rpoS, mlrA, ycfR, fimA, spiA and csgA, biofilm-related genes, were also screened. Results have revealed that 2 log reduction of bacterial strains named above, forming biofilm formation on spinach, have been observed by the help of the extract of stinging nettle with 1-hour exposure time. In vitro, different inhibitory capabilities of the extracts have been observed regarding the concentrations, ranging from 2 mg/ml to 20 mg/ml. The extract has significantly decreased the swimming motilities of serovars, except Enteritidis. Weak and strong biofilm producers have been observed in curli expression. In conclusion, stinging nettle extract plays an important role in eliminating biofilm formation of Salmonella enterica serovars

Molecular evaluation and antimicrobial susceptibility testing of Escherichia coli isolates from food products in Turkey

WOS: 000354886300028Some strains of Escherichia coli can be important food borne pathogens. Characterization and antimicrobial resistance testing of 28 E. coli isolates from random food samples obtained in Van, Turkey were performed. Primers for 6 indicator genes (fliC, stx1, stx2, eae, hlyA, and rfbE) for shiga toxin-producing E. coli and 5 indicator genes for each pathogroup (bfpA, aggR, ipaH, daaD, st, and lt) were used. E. coli isolates were also typed using pulsed field gel electrophoresis with the XbaI restriction enzyme. Antimicrobial susceptibility of E. coli isolates was determined using the disk diffusion method for 17 antimicrobials. E. coli isolates were non-pathogenic strains represented by 25 distinguishable PFGE patterns. Antimicrobial susceptibility testing revealed that more than 40% of the E. coli isolates showed resistance to ampicillin, sulphafurazole, and tetracycline. Antimicrobial susceptibility of commensal E. coli should be monitored because these bacteria are becoming reservoirs of antimicrobial resistance genes.Middle East Technical University (METU), Department of Food Engineering, Ankara, TurkeyMiddle East Technical University; METU Scientific Research Project (BAP)Middle East Technical UniversityThis study was supported by a grant from Middle East Technical University (METU), Department of Food Engineering, Ankara, Turkey. The METU Scientific Research Project (BAP) provided financial support. Dr. Kadir Halkman and Dr. Belkis Levent provided reference strains for STEC and pathogenic E. coli respectively. Dr. Martin Weidmann allowed use of bionumerics in the laboratory

Amyloid deposition in knee and ankle joints in the course of multiple myeloma

WOS: 000246587700024PubMed ID: 1735031

Development and validation of a resistance and virulence gene microarray targeting Escherichia coli and Salmonella enterica

A microarray was developed to simultaneously screen Escherichia coli and Salmonella enterica for multiple genetic traits. The final array included 203 60-mer oligonucleotide probes, including 117 for resistance genes, 16 for virulence genes, 25 for replicon markers, and 45 other markers. Validity of the array was tested by assessing inter-laboratory agreement among four collaborating groups using a blinded study design. Internal validation indicated that the assay was reliable (area under the receiver-operator characteristic curve = 0.97). Inter-laboratory agreement, however, was poor when estimated using the intraclass correlation coefficient, which ranged from 0.27 (95% confidence interval 0.24, 0.29) to 0.29 (0.23, 0.34). These findings suggest that extensive testing and procedure standardization will be needed before bacterial genotyping arrays can be readily shared between laboratories

Multilocus Variable-Number Tandem-Repeat Method for Typing Salmonella enterica Serovar Newport

In recent years, the proportion of Salmonella enterica infections represented by S. enterica serovar Newport has increased markedly among humans and animals. Multilocus variable-number tandem-repeat analysis (MLVA) has proven to be useful in discriminating other highly clonal Salmonella serovars. Here, we report on the development of a highly discriminatory MLVA for Salmonella serovar Newport

Multidrug-Resistant Salmonella Typhimurium, Pacific Northwest, United States

We compared human and bovine isolates of Salmonella enterica using antimicrobial-drug resistance profiles and pulsed-field gel electrophoresis. From 2000 through 2006, we observed an increase in a novel multidrug-resistant clone of S . Typhimurium with no recognized phage type. This clone may represent an emerging epidemic strain in the Pacific Northwest

Emergence, Distribution, and Molecular and Phenotypic Characteristics of Salmonella enterica Serotype 4,5,12:i:–

Salmonella spp. represent one of the most common causes of bacterial foodborne illnesses around the world. The species Salmonella enterica contains more than 2500 serotypes, and emergence of new human pathogenic Salmonella strains and serotypes represents a major public health issue. Salmonella enterica subsp. enterica serotype 4,5,12:i:– represents a monophasic variant of Salmonella Typhimurium, which has rarely been identified before the mid-1990s. The prevalence of this serotype among human salmonellosis cases has increased considerably since the mid-1990s and Salmonella 4,5,12:i:– currently (i.e., the first decade of the 2000s) represents one of the most common serotypes among human cases in many countries around the world. This paper discusses our current knowledge of the global ecology, epidemiology, transmission, and evolution of this emerging Salmonella serotype

A National Registry of Thalassemia in Turkey: Demographic and Disease Characteristics of Patients, Achievements, and Challenges in Prevention

WOS: 000426572200002PubMed ID: 28404539Objective: The Turkish Society of Pediatric Hematology set up a National Hemoglobinopathy Registry to demonstrate the demographic and disease characteristics of patients and assess the efficacy of a hemoglobinopathy control program (HCP) over 10 years in Turkey. Materials and Methods: A total of 2046 patients from 27 thalassemia centers were registered, of which 1988 were eligible for analysis. This cohort mainly comprised patients with beta-thalassemia major (n = 1658, 83.4%) and intermedia (n = 215, 10.8%). Results: The majority of patients were from the coastal areas of Turkey. The high number of patients in Southeastern Anatolia was due to that area having the highest rates of consanguineous marriage and fertility. The most common 11 mutations represented 90% of all beta-thalassemia alleles and 47% of those were IVS1-110(G->A) mutations. The probability of undergoing splenectomy within the first 10 years of life was 20%, a rate unchanged since the 1980s. Iron chelators were administered as monotherapy regimens in 95% of patients and deferasirox was prescribed in 81.3% of those cases. Deferasirox administration was the highest (93.6%) in patients aged <10 years. Of the thalassemia major patients, 5.8% had match-related hemopoietic stem cell transplantation with a success rate of 77%. Cardiac disease was detected as a major cause of death and did not show a decreasing trend in 5-year cohorts since 1999. Conclusion: While the HCP has been implemented since 2003, the affected births have shown a consistent decrease only after 2009, being at lowest 34 cases per year. This program failure resulted from a lack of premarital screening in the majority of cases. Additional problems were unawareness of the risk and misinformation of the at-risk couples. In addition, prenatal diagnosis was either not offered to or was not accepted by the at-risk families. This study indicated that a continuous effort is needed for optimizing the management of thalassemia and the development of strategies is essential for further achievements in the HCP in Turkey.Ege Children's Foundation; Novartis Pharmaceuticals CorporationNovartisThe authors thank Caglar Serdar, Aylin Gokduman, and Tolga Turgay of Plexus Information Technologies for their website support. The current study and the work presented here are from an Investigator Initiated Trial, which was sponsored by the Ege Children's Foundation and funded by Novartis Pharmaceuticals Corporation