Conservation and global distribution of non-canonical antigens in enterotoxigenic Escherichia coli

BACKGROUND: Enterotoxigenic Escherichia coli (ETEC) cause significant diarrheal morbidity and mortality in children of resource-limited regions, warranting development of effective vaccine strategies. Genetic diversity of the ETEC pathovar has impeded development of broadly protective vaccines centered on the classical canonical antigens, the colonization factors and heat-labile toxin. Two non-canonical ETEC antigens, the EtpA adhesin, and the EatA mucinase are immunogenic in humans and protective in animal models. To foster rational vaccine design that complements existing strategies, we examined the distribution and molecular conservation of these antigens in a diverse population of ETEC isolates. METHODS: Geographically diverse ETEC isolates (n = 1159) were interrogated by PCR, immunoblotting, and/or whole genome sequencing (n = 46) to examine antigen conservation. The most divergent proteins were purified and their core functions assessed in vitro. RESULTS: EatA and EtpA or their coding sequences were present in 57.0% and 51.5% of the ETEC isolates overall, respectively; and were globally dispersed without significant regional differences in antigen distribution. These antigens also exhibited \u3e93% amino acid sequence identity with even the most divergent proteins retaining the core adhesin and mucinase activity assigned to the prototype molecules. CONCLUSIONS: EtpA and EatA are well-conserved molecules in the ETEC pathovar, suggesting that they serve important roles in virulence and that they could be exploited for rational vaccine design

Genotypic characterization of a monophasic variant of Salmonella enterica serotype typhimurium in swine in USA Midwest

Non-typhoidal Salmonella enterica are a major human foodborne pathogens worldwide (Kirk et al., 2015). Salmonella enterica is divided into six subspecies and approximately 2,500 serotypes according to the Kauffmann-White scheme (Brenner et al., 2000). Serotype 4,5,12:i:-, a monophasic variant of S. Typhimurium lacking the 2nd phase flagellar antigen. Salmonella 4,5,12:i:- has emerged globally in both humans and animals (Echeita et al., 2001; Switt et al., 2009; Centers for Disease Control and Prevention (CDC), 2013) and pork products and pigs are implicated as important sources of human infections (Mossong et al., 2007; Hauser et al., 2010)

Rifampin-resistant Meningococcal Disease

Rifampin-resistant meningococcal disease occurred in a child who had completed rifampin chemoprophylaxis for exposure to a sibling with meningococcemia. Susceptibility testing of 331 case isolates found only 1 other case of rifampin-resistant disease in Minnesota, USA, during 11 years of statewide surveillance. Point mutations in the RNA polymerase β subunit (rpoB) gene were found in isolates from each rifampin-resistant case-patient

Antimicrobial Synergy between Aminoglycosides and Licorice Extract in Listeria monocytogenes

Listeria monocytogenes is a foodborne pathogen that can develop serious invasive infections. Among foodborne pathogens, L. monocytogenes exhibits the highest case fatality despite antibiotic treatment, suggesting the current therapy should be improved. Although ampicillin and gentamicin are used as a combination therapy to treat listeriosis, our results showed there is no synergy between the two antibiotics. We discovered that aqueous extract of licorice generated significant antimicrobial synergy when combined with aminoglycosides, such as gentamicin, in L. monocytogenes. In the presence of 1 mg/mL licorice extract, for instance, the minimum inhibitory concentration (MIC) of gentamicin was reduced by 32-fold. Moreover, antimicrobial synergy with licorice extract made gentamicin-resistant clinical isolates of L. monocytogenes susceptible to gentamicin. Given the common use of licorice as a food sweetener in Western countries and a herb in Oriental medicine, our findings suggest that licorice extract can be potentially used as an antibiotic adjuvant to improve the efficacy of antimicrobial treatment of listeriosis.</jats:p

Draft Genome Sequences for a Diverse Set of Isolates from 10 Neisseria Species

ABSTRACT Neisseria is a diverse genus that includes commensal and pathogenic species that pose a public health threat. While the pathogenic species have been studied extensively, many of the commensals have limited genomic information available. Here, we present draft genome sequences for a diverse set of 37 isolates from 10 Neisseria species. </jats:p

Antimicrobial Synergy between Aminoglycosides and Licorice Extract in Listeria monocytogenes

Listeria monocytogenes is a foodborne pathogen that can develop serious invasive infections. Among foodborne pathogens, L. monocytogenes exhibits the highest case fatality despite antibiotic treatment, suggesting the current therapy should be improved. Although ampicillin and gentamicin are used as a combination therapy to treat listeriosis, our results showed there is no synergy between the two antibiotics. We discovered that aqueous extract of licorice generated significant antimicrobial synergy when combined with aminoglycosides, such as gentamicin, in L. monocytogenes. In the presence of 1 mg/mL licorice extract, for instance, the minimum inhibitory concentration (MIC) of gentamicin was reduced by 32-fold. Moreover, antimicrobial synergy with licorice extract made gentamicin-resistant clinical isolates of L. monocytogenes susceptible to gentamicin. Given the common use of licorice as a food sweetener in Western countries and a herb in Oriental medicine, our findings suggest that licorice extract can be potentially used as an antibiotic adjuvant to improve the efficacy of antimicrobial treatment of listeriosis

Genotypic characterization of a monophasic variant of Salmonella enterica serotype typhimurium in swine in USA Midwest

Non-typhoidal Salmonella enterica are a major human foodborne pathogens worldwide (Kirk et al., 2015). Salmonella enterica is divided into six subspecies and approximately 2,500 serotypes according to the Kauffmann-White scheme (Brenner et al., 2000). Serotype 4,5,12:i:-, a monophasic variant of S. Typhimurium lacking the 2nd phase flagellar antigen. Salmonella 4,5,12:i:- has emerged globally in both humans and animals (Echeita et al., 2001; Switt et al., 2009; Centers for Disease Control and Prevention (CDC), 2013) and pork products and pigs are implicated as important sources of human infections (Mossong et al., 2007; Hauser et al., 2010).</p

BMScan: using whole genome similarity to rapidly and accurately identify bacterial meningitis causing species

Abstract Background Bacterial meningitis is a life-threatening infection that remains a public health concern. Bacterial meningitis is commonly caused by the following species: Neisseria meningitidis, Streptococcus pneumoniae, Listeria monocytogenes, Haemophilus influenzae and Escherichia coli. Here, we describe BMScan (Bacterial Meningitis Scan), a whole-genome analysis tool for the species identification of bacterial meningitis-causing and closely-related pathogens, an essential step for case management and disease surveillance. BMScan relies on a reference collection that contains genomes for 17 focal species to scan against to identify a given species. We established this reference collection by supplementing publically available genomes from RefSeq with genomes from the isolate collections of the Centers for Disease Control Bacterial Meningitis Laboratory and the Minnesota Department of Health Public Health Laboratory, and then filtered them down to a representative set of genomes which capture the diversity for each species. Using this reference collection, we evaluated two genomic comparison algorithms, Mash and Average Nucleotide Identity, for their ability to accurately and rapidly identify our focal species. Results We found that the results of Mash were strongly correlated with the results of ANI for species identification, while providing a significant reduction in run-time. This drastic difference in run-time enabled the rapid scanning of large reference genome collections, which, when combined with species-specific threshold values, facilitated the development of BMScan. Using a validation set of 15,503 genomes of our species of interest, BMScan accurately identified 99.97% of the species within 16 min 47 s. Conclusions Identification of the bacterial meningitis pathogenic species is a critical step for case confirmation and further strain characterization. BMScan employs species-specific thresholds for previously-validated, genome-wide similarity statistics compiled from a curated reference genome collection to rapidly and accurately identify the species of uncharacterized bacterial meningitis pathogens and closely related pathogens. BMScan will facilitate the transition in public health laboratories from traditional phenotypic detection methods to whole genome sequencing based methods for species identification