Lothar H. Wieler

Chromosomally encoded ESBL genes in Escherichia coli of ST38 from Mongolian wild birds

Objectives ESBL genes in Escherichia coli are mainly plasmid encoded, although recent studies have also shown chromosomal integration, e.g. in clinical E. coli isolates of ST38. As ESBL-producing E. coli are also found in non-clinical settings, we were interested in determining whether chromosomally integrated ESBL genes occur in ST38 isolates from non-clinical habitats, e.g. wildlife. Methods Four ESBL-producing E. coli isolates of ST38 originating from Mongolian birds of prey sampled in 2015 were subjected to a detailed analysis in terms of phenotypic resistance, plasmid profiling and WGS, followed by the determination of genotypic resistance factors including the chromosomal integration of ESBL and carbapenemase genes. Results Results based on phenotypic and genotypic plasmid profiling, contiguous sequence (contig) sizes and PCR analysis of flanking insertion site regions showed that three of four ST38 isolates harboured chromosomally encoded bla CTX-M genes of three different types ( bla CTX-M-14 , bla CTX-M-15 and bla CTX-M-24 ) that were inserted into three different chromosomal locations. A comparison of WGS data with ST38 isolates from a clinical outbreak in the UK indicated only low numbers of core-genome SNPs detected among one Mongolian wild bird isolate and eight clinical isolates from the UK. Conclusions The chromosomal integration of bla CTX-M genes in E. coli isolates of ST38 appears to be common and is likely independent of antimicrobial selective pressure in clinical environments. Our data corroborate the zoonotic potential of environmental isolates of ESBL-producing E. coli , which harbour stably integrated, chromosomally encoded resistance factors.

Persistent anthrax as a major driver of wildlife mortality in a tropical rainforest

Anthrax is a globally important animal disease and zoonosis. Despite this, our current knowledge of anthrax ecology is largely limited to arid ecosystems, where outbreaks are most commonly reported. Here we show that the dynamics of an anthrax-causing agent, Bacillus cereus biovar anthracis, in a tropical rainforest have severe consequences for local wildlife communities. Using data and samples collected over three decades, we show that rainforest anthrax is a persistent and widespread cause of death for a broad range of mammalian hosts. We predict that this pathogen will accelerate the decline and possibly result in the extirpation of local chimpanzee (Pan troglodytes verus) populations. We present the epidemiology of a cryptic pathogen and show that its presence has important implications for conservation.

SLIMM: species level identification of microorganisms from metagenomes

Identification and quantification of microorganisms is a significant step in studying the alpha and beta diversities within and between microbial communities respectively. Both identification and quantification of a given microbial community can be carried out using whole genome shotgun sequences with less bias than when using 16S-rDNA sequences. However, shared regions of DNA among reference genomes and taxonomic units pose a significant challenge in assigning reads correctly to their true origins. The existing microbial community profiling tools commonly deal with this problem by either preparing signature-based unique references or assigning an ambiguous read to its least common ancestor in a taxonomic tree. The former method is limited to making use of the reads which can be mapped to the curated regions, while the latter suffer from the lack of uniquely mapped reads at lower (more specific) taxonomic ranks. Moreover, even if the tools exhibited good performance in calling the organisms present in a sample, there is still room for improvement in determining the correct relative abundance of the organisms. We present a new method Species Level Identification of Microorganisms from Metagenomes (SLIMM) which addresses the above issues by using coverage information of reference genomes to remove unlikely genomes from the analysis and subsequently gain more uniquely mapped reads to assign at lower ranks of a taxonomic tree. SLIMM is based on a few, seemingly easy steps which when combined create a tool that outperforms state-of-the-art tools in run-time and memory usage while being on par or better in computing quantitative and qualitative information at species-level.

Performance of complement fixation test and confirmatory immunoblot as two-cascade testing approach for serodiagnosis of glanders in an endemic region of South East Asia.

Various serological tests were used for the diagnosis of glanders in the past but still complement fixation test (CFT) is the internationally prescribed test for trading equines. A new immunoblot (IB) technique has recently been introduced to overcome the well known shortcomings of CFT i. e. a considerable number of false positive and negative results and anticomplementary effects of sera. The objective of this study was the comparative evaluation of two glanders CFT antigens commercially available at Central Veterinary Institute ofWageningen UR, Lelystad, NL (CIDC) and at c.c.pro GmbH, Oberdorla, DE (c.c.pro) in a glanders endemic area regarding specificity and sensitivity. A total of 1678 serum samples from the endemic region (Province Punjab, Pakistan) and a non-endemic area (Germany) were analysed. All sera tested positive or suspicious with CFT were analysed by the confirmatory IB to exclude CFT false positive results. Both CFT antigens showed 100% sensitivity. The use of CIDC or c.c.pro antigen resulted in specificities of 77.45% or 75.71% for sera from endemic area and 93.75% or 94.79% for sera from non-endemic areas, respectively. The results demonstrate the different performances of identical tests in different epidemiologically settings. Based on these results, the combined use of CFT and IB is highly suggestive for the serodiagnosis of glanders. Good agreement was calculated between CFT (using either c.c.pro or CIDC antigen) and immunoblot.

Risk of Transmission of Antimicrobial Resistant Escherichia coli from Commercial Broiler and Free-Range Retail Chicken in India

Multidrug-resistant Escherichia coli infections are a growing public health concern. This study analyzed the possibility of contamination of commercial poultry meat (broiler and free-range) with pathogenic and or multi-resistant E. coli in retail chain poultry meat markets in India. We analyzed 168 E. coli isolates from broiler and free-range retail poultry (meat/ceca) sampled over a wide geographical area, for their antimicrobial sensitivity, phylogenetic groupings, virulence determinants, extended-spectrum-β-lactamase (ESBL) genotypes, fingerprinting by Enterobacterial Repetitive Intergenic Consensus (ERIC) PCR and genetic relatedness to human pathogenic E. coli using whole genome sequencing (WGS). The prevalence rates of ESBL producing E. coli among broiler chicken were: meat 46%; ceca 40%. Whereas, those for free range chicken were: meat 15%; ceca 30%. E. coli from broiler and free-range chicken exhibited varied prevalence rates for multi-drug resistance (meat 68%; ceca 64% and meat 8%; ceca 26%, respectively) and extraintestinal pathogenic E. coli (ExPEC) contamination (5 and 0%, respectively). WGS analysis confirmed two globally emergent human pathogenic lineages of E. coli, namely the ST131 (H30-Rx subclone) and ST117 among our poultry E. coli isolates. These results suggest that commercial poultry meat is not only an indirect public health risk by being a possible carrier of non-pathogenic multi-drug resistant (MDR)-E. coli, but could as well be the carrier of human E. coli pathotypes. Further, the free-range chicken appears to carry low risk of contamination with antimicrobial resistant and extraintestinal pathogenic E. coli (ExPEC). Overall, these observations reinforce the understanding that poultry meat in the retail chain could possibly be contaminated by MDR and/or pathogenic E. coli.

[Multidrug-resistant bacteria in Germany. The impact of sources outside healthcare facilities].

BACKGROUND Currently, there is an ongoing discussion about the question whether the emergence of multidrug-resistant microorganisms (MDRO) among humans is due to transfer of these bacteria from animals. OBJECTIVES This review summarizes data on the occurrence of methicillin-resistant Staphylococcus aureus (MRSA) and extended-spectrum beta-lactamase (ESBL) producing enterobacteria in animals and humans, and describes knowledge about transmission pathways. MATERIAL AND METHODS After a scientific literature analysis, relevant articles were identified by screening of titles and abstracts, amended by publications of infection control authorities and the respective reference lists. RESULTS MDRO are both transmitted in the nosocomial setting and are increasingly detected as sources of infection outside healthcare facilities. CONCLUSIONS Due to new transmission pathways of MDRO an inter-disciplinary approach towards prevention is necessary, involving medical, pharmaceutical and veterinary expertise.ZusammenfassungHintergrundDie Frage, ob die zunehmende Verbreitung von Erregern mit Antibiotika-Multiresistenzen (MRE) beim Menschen durch Übertragungen von Tieren erklärbar ist, wird öffentlich diskutiert.Ziel der ArbeitDiese Übersichtsarbeit trägt Daten zum Vorkommen von Methicillin-resistenten Staphylococcus aureus (MRSA) und Extended-Spectrum Beta-Lactamase (ESBL) bildenden Enterobakterien bei Mensch und Tier zusammen und beschreibt die Erkenntnisse zur zoonotischen Transmission.Material und MethodenEs wurde eine Literaturrecherche durchgeführt. Relevante Literatur wurde durch Screening von Überschriften und Abstracts identifiziert und ergänzt durch Publikationen von Infektionsschutzbehörden bzw. die dort zitierten Originalarbeiten.ErgebnisseEs zeigte sich eine Vielzahl nosokomialer Verbreitungswege von MRE sowie eine zunehmende Relevanz von außerhalb des Gesundheitswesens gelegenen Infektionsquellen.DiskussionFür eine effektive Prävention von MRE ist ein interdisziplinärer Ansatz notwendig, der sowohl die Grenzen medizinischer und pharmazeutischer Fachgebiete als auch die Grenzen zwischen Human- und Veterinärmedizin überschreitet.AbstractBackgroundCurrently, there is an ongoing discussion about the question whether the emergence of multidrug-resistant microorganisms (MDRO) among humans is due to transfer of these bacteria from animals.ObjectivesThis review summarizes data on the occurrence of methicillin-resistant Staphylococcus aureus (MRSA) and extended-spectrum beta-lactamase (ESBL) producing enterobacteria in animals and humans, and describes knowledge about transmission pathways.Material and methodsAfter a scientific literature analysis, relevant articles were identified by screening of titles and abstracts, amended by publications of infection control authorities and the respective reference lists.ResultsMDRO are both transmitted in the nosocomial setting and are increasingly detected as sources of infection outside healthcare facilities.ConclusionsDue to new transmission pathways of MDRO an inter-disciplinary approach towards prevention is necessary, involving medical, pharmaceutical and veterinary expertise.

First report of two complete Clostridium chauvoei genome sequences and detailed in silico genome analysis

Clostridium (C.) chauvoei is a Gram-positive, spore forming, anaerobic bacterium. It causes black leg in ruminants, a typically fatal histotoxic myonecrosis. High quality circular genome sequences were generated for the C. chauvoei type strain DSM 7528T (ATCC 10092T) and a field strain 12S0467 isolated in Germany. The origin of replication (oriC) was comparable to that of Bacillus subtilis in structure with two regions containing DnaA boxes. Similar prophages were identified in the genomes of both C. chauvoei strains which also harbored hemolysin and bacterial spore formation genes. A CRISPR type I-B system with limited variations in the repeat number was identified. Sporulation and germination process related genes were homologous to that of the Clostridia cluster I group but novel variations for regulatory genes were identified indicative for strain specific control of regulatory events. Phylogenomics showed a higher relatedness to C. septicum than to other so far sequenced genomes of species belonging to the genus Clostridium. Comparative genome analysis of three C. chauvoei circular genome sequences revealed the presence of few inversions and translocations in locally collinear blocks (LCBs). The species genome also shows a large number of genes involved in proteolysis, genes for glycosyl hydrolases and metal iron transportation genes which are presumably involved in virulence and survival in the host. Three conserved flagellar genes (fliC) were identified in each of the circular genomes. In conclusion this is the first comparative analysis of circular genomes for the species C. chauvoei, enabling insights into genome composition and virulence factor variation.

Antibiotika-resistente Erreger in Deutschland

BACKGROUND Currently, there is an ongoing discussion about the question whether the emergence of multidrug-resistant microorganisms (MDRO) among humans is due to transfer of these bacteria from animals. OBJECTIVES This review summarizes data on the occurrence of methicillin-resistant Staphylococcus aureus (MRSA) and extended-spectrum beta-lactamase (ESBL) producing enterobacteria in animals and humans, and describes knowledge about transmission pathways. MATERIAL AND METHODS After a scientific literature analysis, relevant articles were identified by screening of titles and abstracts, amended by publications of infection control authorities and the respective reference lists. RESULTS MDRO are both transmitted in the nosocomial setting and are increasingly detected as sources of infection outside healthcare facilities. CONCLUSIONS Due to new transmission pathways of MDRO an inter-disciplinary approach towards prevention is necessary, involving medical, pharmaceutical and veterinary expertise.ZusammenfassungHintergrundDie Frage, ob die zunehmende Verbreitung von Erregern mit Antibiotika-Multiresistenzen (MRE) beim Menschen durch Übertragungen von Tieren erklärbar ist, wird öffentlich diskutiert.Ziel der ArbeitDiese Übersichtsarbeit trägt Daten zum Vorkommen von Methicillin-resistenten Staphylococcus aureus (MRSA) und Extended-Spectrum Beta-Lactamase (ESBL) bildenden Enterobakterien bei Mensch und Tier zusammen und beschreibt die Erkenntnisse zur zoonotischen Transmission.Material und MethodenEs wurde eine Literaturrecherche durchgeführt. Relevante Literatur wurde durch Screening von Überschriften und Abstracts identifiziert und ergänzt durch Publikationen von Infektionsschutzbehörden bzw. die dort zitierten Originalarbeiten.ErgebnisseEs zeigte sich eine Vielzahl nosokomialer Verbreitungswege von MRE sowie eine zunehmende Relevanz von außerhalb des Gesundheitswesens gelegenen Infektionsquellen.DiskussionFür eine effektive Prävention von MRE ist ein interdisziplinärer Ansatz notwendig, der sowohl die Grenzen medizinischer und pharmazeutischer Fachgebiete als auch die Grenzen zwischen Human- und Veterinärmedizin überschreitet.AbstractBackgroundCurrently, there is an ongoing discussion about the question whether the emergence of multidrug-resistant microorganisms (MDRO) among humans is due to transfer of these bacteria from animals.ObjectivesThis review summarizes data on the occurrence of methicillin-resistant Staphylococcus aureus (MRSA) and extended-spectrum beta-lactamase (ESBL) producing enterobacteria in animals and humans, and describes knowledge about transmission pathways.Material and methodsAfter a scientific literature analysis, relevant articles were identified by screening of titles and abstracts, amended by publications of infection control authorities and the respective reference lists.ResultsMDRO are both transmitted in the nosocomial setting and are increasingly detected as sources of infection outside healthcare facilities.ConclusionsDue to new transmission pathways of MDRO an inter-disciplinary approach towards prevention is necessary, involving medical, pharmaceutical and veterinary expertise.

Analysis of mutations in pncA reveals non-overlapping patterns among various lineages of Mycobacterium tuberculosis

Pyrazinamide (PZA) is an important first-line anti-tuberculosis drug, resistance to which occurs primarily due to mutations in pncA (Rv2043c) that encodes the pyrazinamidase enzyme responsible for conversion of pro-drug PZA into its active form. Previous studies have reported numerous resistance-conferring mutations distributed across the entire length of pncA without any hotspot regions. As different lineages of Mycobacterium tuberculosis display a strong geographic association, we sought to understand whether the genetic background influenced the distribution of mutations in pncA. We analyzed the whole genome sequence data of 1,480 clinical isolates representing four major M. tuberculosis lineages to identify the distribution of mutations in the complete operon (Rv2044c-pncA-Rv2042c) and its upstream promoter region. We observed a non-overlapping pattern of mutations among various lineages and identified a lineage 3-specific frame-shift deletion in gene Rv2044c upstream of pncA that disrupted the stop codon and led to its fusion with pncA. This resulted in the addition of a novel domain of unknown function (DUF2784) to the pyrazinamidase enzyme. The variant molecule was computationally modelled and physico-chemical parameters determined to ascertain stability. Although the functional impact of this mutation remains unknown, its lineage specific nature highlights the importance of genetic background and warrants further study.

Beta-hemolytic Streptococcus dysgalactiae strains isolated from horses are a genetically distinct population within the Streptococcus dysgalactiae taxon

The pathogenic role of beta-hemolytic Streptococcus dysgalactiae in the equine host is increasingly recognized. A collection of 108 Lancefield group C (n = 96) or L (n = 12) horse isolates recovered in the United States and in three European countries presented multilocus sequence typing (MLST) alleles, sequence types and emm types (only 56% of the isolates could be emm typed) that were, with few exceptions, distinct from those previously found in human Streptococcus dysgalactiae subsp. equisimilis. Characterization of a subset of horse isolates by multilocus sequence analysis (MLSA) and 16S rRNA gene sequence showed that most equine isolates could also be differentiated from S. dysgalactiae strains from other animal species, supporting the existence of a horse specific genomovar. Draft genome information confirms the distinctiveness of the horse genomovar and indicates the presence of potentially horse-specific virulence factors. While this genomovar represents most of the isolates recovered from horses, a smaller MLST and MLSA defined sub-population seems to be able to cause infections in horses, other animals and humans, indicating that transmission between hosts of strains belonging to this group may occur.