Limited genetic diversity in Salmonella enterica Serovar Enteritidis PT13

<p>Abstract</p> <p>Background</p> <p><it>Salmonella enterica </it>serovar Enteritidis has emerged as a significant foodborne pathogen throughout the world and is commonly characterized by phage typing. In Canada phage types (PT) 4, 8 and 13 predominate and in 2005 a large foodborne PT13 outbreak occurred in the province of Ontario. The ability to link strains during this outbreak was difficult due to the apparent clonality of PT13 isolates in Canada, as there was a single dominant pulsed-field gel electrophoresis (PFGE) profile amongst epidemiologically linked human and food isolates as well as concurrent sporadic strains. The aim of this study was to perform comparative genomic hybridization (CGH), DNA sequence-based typing (SBT) genomic analyses, plasmid analyses, and automated repetitive sequence-based PCR (rep-PCR) to identify epidemiologically significant traits capable of subtyping <it>S</it>. Enteritidis PT13.</p> <p>Results</p> <p>CGH using an oligonucleotide array based upon chromosomal coding sequences of <it>S. enterica </it>serovar Typhimurium strain LT2 and the <it>Salmonella </it>genomic island 1 successfully determined major genetic differences between <it>S</it>. Typhimurium and <it>S</it>. Enteritidis PT13, but no significant strain-to-strain differences were observed between <it>S</it>. Enteritidis PT13 isolates. Individual loci (<it>safA </it>and <it>fliC</it>) that were identified as potentially divergent in the CGH data set were sequenced in a panel of <it>S</it>. Enteritidis strains, and no differences were detected between the PT13 strains. Additional sequence-based typing was performed at the <it>fimA</it>, <it>mdh</it>, <it>manB</it>, <it>cyaA</it>, <it>citT</it>, <it>caiC</it>, <it>dmsA</it>, <it>ratA </it>and STM0660 loci. Similarly, no diversity was observed amongst PT13 strains. Variation in plasmid content between PT13 strains was observed, but macrorestriction with B<it>gl</it>II did not identify further differences. Automated rep-PCR patterns were variable between serovars, but <it>S</it>. Enteritidis PT13 strains could not be differentiated.</p> <p>Conclusion</p> <p>None of the methods identified any significant variation between PT13 strains. Greater than 11,300 base pairs of sequence for each of seven <it>S</it>. Enteritidis PT13 strains were analyzed without detecting a single polymorphic site, although diversity between different phage types of <it>S</it>. Enteritidis was observed. These data suggest that Canadian <it>S</it>. Enteritidis PT13 strains are highly related genetically.</p

WGS to predict antibiotic MICs for Neisseria gonorrhoeae

Background: Tracking the spread of antimicrobial resistant Neisseria gonorrhoeae is a major priority for national surveillance programmes. Objectives: We investigate whether whole-genome sequencing, WGS, and simultaneous analysis of multiple resistance determinants can be used to predict antimicrobial susceptibilities to the level of minimum inhibitory concentrations, MICs, in N. gonorrhoeae. Methods: WGS was used to identify previously reported potential resistance determinants in 681 N. gonorrhoeae isolates, from England, the USA and Canada, with phenotypes for cefixime, penicillin, azithromycin, ciprofloxacin, and tetracycline determined as part of national surveillance programmes. Multivariate linear regression models were used to identify genetic predictors of MIC. Model performance was assessed using leave-one-out cross validation. Results: Overall 1785/3380(53%) MIC values were predicted to the nearest doubling dilution, and 3147(93%) within ±1 and 3314(98%) within ±2 doubling-dilutions. MIC prediction performance was similar across the five antimicrobials tested. Prediction models included the majority of previously reported resistance determinants. Applying EUCAST breakpoints to MIC predictions, the overall very major error rate (VME, phenotypically resistant, WGS-prediction sensitive) was 21/1577(1.3%, 95%CI 0.8-2.0%), and the major error rate (ME, phenotypically sensitive, WGS-prediction resistant) was 20/1186(1.7%, 1.0-2.6%). VME rates met regulatory thresholds for all antimicrobials except cefixime and ME rates for all antimicrobials except tetracycline. Country of testing was a strongly significant predictor of MIC for all 5 antimicrobials. Conclusions: We demonstrate a WGS-based MIC prediction approach that allows reliable MIC prediction for five gonorrhoea antimicrobials. Our approach should allow reasonably precise prediction of MICs for a range of bacterial species

Analysis of multidrug resistance in the predominant Streptococcus pneumoniae serotypes in Canada:the SAVE study, 2011-15

Objectives: This study assessed MDR invasive isolates of Streptococcus pneumoniae, in relation to serotype evolution in Canada between 2011 and 2015 as part of the annual SAVE study. Methods: As part of a collaboration between the Canadian Antimicrobial Resistance Alliance and Public Health Agency of Canada-National Microbiology Laboratory, 6207 invasive isolates of S. pneumoniae were evaluated. All isolates were serotyped and had antimicrobial susceptibility testing performed, in accordance with CLSI guidelines (M07-A10, 2015). Complete susceptibility profiles were available for 6001 isolates. MDR was defined as resistance to three or more classes of antimicrobial agents (with penicillin MIC ≥2 mg/L defined as resistant). Results: The overall rate of MDR S. pneumoniae was 6.2% (372/6001) in SAVE, decreasing significantly from 8.5% in 2011 to 5.6% in 2015 (P = 0.0041). MDR was observed in 32 serotypes, with serotypes 15A and 19A predominating (26.6% and 41.7% of the MDR isolates, respectively). The overall proportion of serotypes 19A, 7F and 33A decreased significantly (P 5%) for 24F and 33F. Conclusions: In 2015, 56.3% of invasive MDR S. pneumoniae were serotypes included in the PCV-13 vaccine. PCV-13 includes the most commonly identified serotype, 19A; however, other increasingly important MDR serotypes, such as 15A, 24F and 33F, are notably not in the currently used vaccines

Ceftiofur Resistance in Salmonella enterica Serovar Heidelberg from Chicken Meat and Humans, Canada

Use of this drug in chickens may limit effectiveness of cephalosporins in treating human infections

Trends in invasive bacterial diseases during the first 2 years of the COVID-19 pandemic: analyses of prospective surveillance data from 30 countries and territories in the IRIS Consortium

Background The Invasive Respiratory Infection Surveillance (IRIS) Consortium was established to assess the impact of the COVID-19 pandemic on invasive diseases caused by Streptococcus pneumoniae, Haemophilus influenzae, Neisseria meningitidis, and Streptococcus agalactiae. We aimed to analyse the incidence and distribution of these diseases during the first 2 years of the COVID-19 pandemic compared to the 2 years preceding the pandemic. Methods For this prospective analysis, laboratories in 30 countries and territories representing five continents submitted surveillance data from Jan 1, 2018, to Jan 2, 2022, to private projects within databases in PubMLST. The impact of COVID-19 containment measures on the overall number of cases was analysed, and changes in disease distributions by patient age and serotype or group were examined. Interrupted time-series analyses were done to quantify the impact of pandemic response measures and their relaxation on disease rates, and autoregressive integrated moving average models were used to estimate effect sizes and forecast counterfactual trends by hemisphere. Findings Overall, 116 841 cases were analysed: 76 481 in 2018–19, before the pandemic, and 40 360 in 2020–21, during the pandemic. During the pandemic there was a significant reduction in the risk of disease caused by S pneumoniae (risk ratio 0·47; 95% CI 0·40–0·55), H influenzae (0·51; 0·40–0·66) and N meningitidis (0·26; 0·21–0·31), while no significant changes were observed for S agalactiae (1·02; 0·75–1·40), which is not transmitted via the respiratory route. No major changes in the distribution of cases were observed when stratified by patient age or serotype or group. An estimated 36 289 (95% prediction interval 17 145–55 434) cases of invasive bacterial disease were averted during the first 2 years of the pandemic among IRIS-participating countries and territories. Interpretation COVID-19 containment measures were associated with a sustained decrease in the incidence of invasive disease caused by S pneumoniae, H influenzae, and N meningitidis during the first 2 years of the pandemic, but cases began to increase in some countries towards the end of 2021 as pandemic restrictions were lifted. These IRIS data provide a better understanding of microbial transmission, will inform vaccine development and implementation, and can contribute to health-care service planning and provision of policies. Funding Wellcome Trust, NIHR Oxford Biomedical Research Centre, Spanish Ministry of Science and Innovation, Korea Disease Control and Prevention Agency, Torsten Söderberg Foundation, Stockholm County Council, Swedish Research Council, German Federal Ministry of Health, Robert Koch Institute, Pfizer, Merck, and the Greek National Public Health Organization

Trends in invasive bacterial diseases during the first 2 years of the COVID-19 pandemic: analyses of prospective surveillance data from 30 countries and territories in the IRIS Consortium.

BACKGROUND The Invasive Respiratory Infection Surveillance (IRIS) Consortium was established to assess the impact of the COVID-19 pandemic on invasive diseases caused by Streptococcus pneumoniae, Haemophilus influenzae, Neisseria meningitidis, and Streptococcus agalactiae. We aimed to analyse the incidence and distribution of these diseases during the first 2 years of the COVID-19 pandemic compared to the 2 years preceding the pandemic. METHODS For this prospective analysis, laboratories in 30 countries and territories representing five continents submitted surveillance data from Jan 1, 2018, to Jan 2, 2022, to private projects within databases in PubMLST. The impact of COVID-19 containment measures on the overall number of cases was analysed, and changes in disease distributions by patient age and serotype or group were examined. Interrupted time-series analyses were done to quantify the impact of pandemic response measures and their relaxation on disease rates, and autoregressive integrated moving average models were used to estimate effect sizes and forecast counterfactual trends by hemisphere. FINDINGS Overall, 116 841 cases were analysed: 76 481 in 2018-19, before the pandemic, and 40 360 in 2020-21, during the pandemic. During the pandemic there was a significant reduction in the risk of disease caused by S pneumoniae (risk ratio 0·47; 95% CI 0·40-0·55), H influenzae (0·51; 0·40-0·66) and N meningitidis (0·26; 0·21-0·31), while no significant changes were observed for S agalactiae (1·02; 0·75-1·40), which is not transmitted via the respiratory route. No major changes in the distribution of cases were observed when stratified by patient age or serotype or group. An estimated 36 289 (95% prediction interval 17 145-55 434) cases of invasive bacterial disease were averted during the first 2 years of the pandemic among IRIS-participating countries and territories. INTERPRETATION COVID-19 containment measures were associated with a sustained decrease in the incidence of invasive disease caused by S pneumoniae, H influenzae, and N meningitidis during the first 2 years of the pandemic, but cases began to increase in some countries towards the end of 2021 as pandemic restrictions were lifted. These IRIS data provide a better understanding of microbial transmission, will inform vaccine development and implementation, and can contribute to health-care service planning and provision of policies. FUNDING Wellcome Trust, NIHR Oxford Biomedical Research Centre, Spanish Ministry of Science and Innovation, Korea Disease Control and Prevention Agency, Torsten Söderberg Foundation, Stockholm County Council, Swedish Research Council, German Federal Ministry of Health, Robert Koch Institute, Pfizer, Merck, and the Greek National Public Health Organization

Diversity of transducer-like proteins (Tlps) in Campylobacter.

Campylobacter transducer-like proteins (Tlps), also known as methyl-accepting chemotaxis proteins (MCPs), are associated with virulence as well as niche and host adaptation. While functional attributes of these proteins are being elucidated, little has been published regarding their sequence diversity or chromosomal locations and context, although they appear to define invertible regions within Campylobacter jejuni genomes. Genome assemblies for several species of Campylobacter were obtained from the publicly available NCBI repositories. Genomes from all isolates were obtained from GenBank and assessed for Tlp content, while data from isolates with complete, finished genomes were used to determine the identity of Tlps as well as the gene content of putative invertible elements (IEs) in C. jejuni (Cj) and C. coli (Cc). Tlps from several Campylobacter species were organized into a nomenclature system and novel Tlps were defined and named for Cj and Cc. The content of Tlps appears to be species-specific, though diverse within species. Cj and Cc carried overlapping, related Tlp content, as did the three C. fetus subspecies. Tlp1 was detected in 88% of Cj isolates and approximately 43% of Cc, and was found in a different conserved chromosomal location and genetic context in each species. Tlp1 and Tlp 3 predominated in genomes from Cj whereas other Tlps were detected less frequently. Tlp13 and Tlp20 predominated in genomes from Cc while some Cj/Cc Tlps were not detected at all. Tlps 2-4 and 11-20 were less frequently detected and many showed sequence heterogeneity that could affect substrate binding, signal transduction, or both. Tlps other than Tlp1, 7, and 10 had substantial sequence identity in the C-terminal half of the protein, creating chromosomal repeats potentially capable of mediating the inversion of large chromosomal DNA. Cj and Cc Tlps were both found in association with only 14 different genes, indicating a limited genomic context. In Cj these Tlps defined IEs that were for the most part found at a single chromosomal location and comprised of a conserved set of genes. Cc IEs were situated at very different chromosomal locations, had different structures than Cj IEs, and were occasionally incomplete, therefore not capable of inversion. Tlps may have a role in Campylobacter genome structure and dynamics as well as acting as chemoreceptors mediating chemotactic responses

Variability of amino acids in Cj and Cc Tlp proteins.

Variability of amino acids in Cj and Cc Tlp proteins.</p