RESUMO
The discovery of antibiotics more than 80 years ago has led to considerable improvements in human and animal health. Although antibiotic resistance in environmental bacteria is ancient, resistance in human pathogens is thought to be a modern phenomenon that is driven by the clinical use of antibiotics1. Here we show that particular lineages of methicillin-resistant Staphylococcus aureus-a notorious human pathogen-appeared in European hedgehogs in the pre-antibiotic era. Subsequently, these lineages spread within the local hedgehog populations and between hedgehogs and secondary hosts, including livestock and humans. We also demonstrate that the hedgehog dermatophyte Trichophyton erinacei produces two ß-lactam antibiotics that provide a natural selective environment in which methicillin-resistant S. aureus isolates have an advantage over susceptible isolates. Together, these results suggest that methicillin resistance emerged in the pre-antibiotic era as a co-evolutionary adaptation of S. aureus to the colonization of dermatophyte-infected hedgehogs. The evolution of clinically relevant antibiotic-resistance genes in wild animals and the connectivity of natural, agricultural and human ecosystems demonstrate that the use of a One Health approach is critical for our understanding and management of antibiotic resistance, which is one of the biggest threats to global health, food security and development.
Assuntos
Antibacterianos/história , Arthrodermataceae/metabolismo , Ouriços/metabolismo , Ouriços/microbiologia , Resistência a Meticilina/genética , Staphylococcus aureus Resistente à Meticilina/genética , Seleção Genética/genética , Animais , Antibacterianos/metabolismo , Arthrodermataceae/genética , Dinamarca , Europa (Continente) , Evolução Molecular , Mapeamento Geográfico , História do Século XX , Humanos , Staphylococcus aureus Resistente à Meticilina/metabolismo , Nova Zelândia , Saúde Única , Penicilinas/biossíntese , Filogenia , beta-Lactamas/metabolismoRESUMO
Triclocarban (TCC), a formerly used disinfectant, kills bacteria via an unknown mechanism of action. A structural hallmark is its N,N'-diaryl urea motif, which is also present in other antibiotics, including the recently reported small molecule PK150. We show here that, like PK150, TCC exhibits an inhibitory effect on Staphylococcus aureus menaquinone metabolism via inhibition of the biosynthesis protein demethylmenaquinone methyltransferase (MenG). However, the activity spectrum (MIC90) of TCC across a broad range of multidrug-resistant staphylococcus and enterococcus strains was much narrower than that of PK150. Accordingly, TCC did not cause an overactivation of signal peptidase SpsB, a hallmark of the PK150 mode of action. Furthermore, we were able to rule out inhibition of FabI, a confirmed target of the diaryl ether antibiotic triclosan (TCS). Differences in the target profiles of TCC and TCS were further investigated by proteomic analysis, showing complex but rather distinct changes in the protein expression profile of S. aureus Downregulation of the arginine deiminase pathway provided additional evidence for an effect on bacterial energy metabolism by TCC.IMPORTANCE TCC's widespread use as an antimicrobial agent has made it a ubiquitous environmental pollutant despite its withdrawal due to ecological and toxicological concerns. With its antibacterial mechanism of action still being unknown, we undertook a comparative target analysis between TCC, PK150 (a recently discovered antibacterial compound with structural resemblance to TCC), and TCS (another widely employed chlorinated biphenyl antimicrobial) in the bacterium Staphylococcus aureus We show that there are distinct differences in each compound's mode of action, but also identify a shared target between TCC and PK150, the interference with menaquinone metabolism by inhibition of MenG. The prevailing differences, however, which also manifest in a remarkably better broad-spectrum activity of PK150, suggest that even high levels of TCC or TCS resistance observed by continuous environmental exposure may not affect the potential of PK150 or related N,N'-diaryl urea compounds as new antibiotic drug candidates against multidrug-resistant infections.
Assuntos
Proteínas de Bactérias/genética , Carbanilidas/farmacologia , Desinfetantes/farmacologia , Enterococcus/efeitos dos fármacos , Metiltransferases/genética , Staphylococcus aureus/efeitos dos fármacos , Proteínas de Bactérias/metabolismo , Enterococcus/genética , Enterococcus/metabolismo , Metiltransferases/metabolismo , Staphylococcus aureus/genética , Staphylococcus aureus/metabolismoRESUMO
Similar to mecA, mecC confers resistance against beta-lactams, leading to the phenotype of methicillin-resistant Staphylococcus aureus (MRSA). However, mecC-harboring MRSA strains pose special difficulties in their detection. The aim of this study was to assess and compare different phenotypic systems for screening, identification, and susceptibility testing of mecC-positive MRSA isolates. A well-characterized collection of mecC-positive S. aureus isolates (n = 111) was used for evaluation. Routinely used approaches were studied to determine their suitability to correctly identify mecC-harboring MRSA, including three (semi)automated antimicrobial susceptibility testing (AST) systems and five selective chromogenic agar plates. Additionally, a cefoxitin disk diffusion test and an oxacillin broth microdilution assay were examined. All mecC-harboring MRSA isolates were able to grow on all chromogenic MRSA screening plates tested. Detection of these isolates in AST systems based on cefoxitin and/or oxacillin testing yielded overall positive agreements with the mecC genotype of 97.3% (MicroScan WalkAway; Siemens), 91.9% (Vitek 2; bioMérieux), and 64.9% (Phoenix, BD). The phenotypic resistance pattern most frequently observed by AST devices was "cefoxitin resistance/oxacillin susceptibility," ranging from 54.1% (Phoenix) and 83.8% (Vitek 2) to 92.8% (WalkAway). The cefoxitin disk diffusion and oxacillin broth microdilution assays categorized 100% and 61.3% of isolates to be MRSA, respectively. The chromogenic media tested confirmed their suitability to reliably screen for mecC-harboring MRSA. The AST systems showed false-negative results with varying numbers, misidentifying mecC-harboring MRSA as methicillin-susceptible S. aureus This study underlines cefoxitin's status as the superior surrogate mecC-positive MRSA marker.
Assuntos
Antibacterianos/farmacologia , Proteínas de Bactérias/genética , Cefoxitina/farmacologia , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/isolamento & purificação , Testes de Sensibilidade Microbiana/métodos , Oxacilina/farmacologia , Proteínas de Ligação às Penicilinas/genética , Infecções Estafilocócicas/microbiologia , Humanos , Staphylococcus aureus Resistente à Meticilina/genética , Fenótipo , Infecções Estafilocócicas/diagnósticoRESUMO
Objectives: Linezolid-resistant Staphylococcus epidermidis (LRSE) and linezolid-dependent ST22 strains have been shown to predominate in tertiary care facilities all over Greece. We report herein the dissemination of ST22 but also ST2, ST5 and ST168 linezolid-dependent LRSE clones in four unrelated German hospitals. Methods: Fourteen LRSE clinical isolates recovered during 2012-14 from five distantly located German hospitals were tested by for MIC determination broth microdilution and Etest, PCR/sequencing for cfr and for mutations in 23S rRNA, rplC, rplD and rplV genes, MLST, PFGE and growth curves without and with linezolid at 16 and 32 mg/L. Results: Most (11, 78.6%) isolates had linezolid MICs >256 mg/L. Five isolates carried the cfr gene. Eight isolates belonged to ST22, two isolates each to ST168 and ST2 and one isolate each to ST5 and ST23. Ten isolates [seven belonging to ST22 and one to each of ST2, ST5 and ST168; all these STs belong to clonal complex (CC) 5] exhibited linezolid-dependent growth, growing significantly faster in linezolid-containing broth. Four isolates were non-dependent (one belonging to each of ST22, ST2, ST23 and ST168). Four isolates came from three different hospitals, whereas four and six isolates were recovered during outbreaks of LRSE in two distinct hospitals. Conclusions: The multi-clonal dissemination of CC5 linezolid-dependent LRSE throughout German hospitals along with the clonal expansion of ST22 linezolid-dependent LRSE in Greek hospitals is of particular concern. It is plausible that this characteristic is inherent and provides a selective advantage to CC5 LRSE under linezolid pressure, contributing to their dissemination throughout hospitals in these countries.
Assuntos
Antibacterianos/farmacologia , Infecção Hospitalar/epidemiologia , Genótipo , Linezolida/farmacologia , Infecções Estafilocócicas/epidemiologia , Staphylococcus epidermidis/efeitos dos fármacos , Antibacterianos/metabolismo , Proteínas de Bactérias/genética , Infecção Hospitalar/microbiologia , Transmissão de Doença Infecciosa , Alemanha/epidemiologia , Hospitais , Humanos , Linezolida/metabolismo , Testes de Sensibilidade Microbiana , Epidemiologia Molecular , Tipagem Molecular , RNA Ribossômico 23S/genética , Análise de Sequência de DNA , Infecções Estafilocócicas/microbiologia , Staphylococcus epidermidis/genética , Staphylococcus epidermidis/crescimento & desenvolvimento , Staphylococcus epidermidis/isolamento & purificaçãoRESUMO
Objectives: To investigate an outbreak of linezolid-resistant Staphylococcus epidermidis (LRSE) in an interdisciplinary ICU, linezolid consumption and infection control measures taken. Methods: Routine surveillance of nosocomial infections revealed colonization and infection with LRSE affecting 14 patients during a 15 month period. LRSE isolates were analysed with respect to their clonal relatedness, antimicrobial susceptibility, the presence of cfr and/or mutations in the 23S rRNA, rplC, rplD and rplV genes. cfr plasmids were characterized by Illumina sequencing. Medical records were reviewed and antibiotic consumption was determined. Results: Molecular typing identified the presence of three different LRSE clusters: PFGE type I/ST168 (n = 5), PFGE type II/ST5 (n = 10) and PFGE type III/ST2 (n = 1). Ten strains harboured the cfr gene; we also detected mutations in the respective ribosomal protein genes. WGS revealed an almost identical 39 kb cfr plasmid obtained from strains of different genetic background (ST2, ST5, ST168) that shows high similarity to the recently published LRSE plasmid p12-02300. Due to an increase in the number of patients treated for infections with MRSA, a significant increase in linezolid usage was noted from January to July 2014 (from 5.55 to 20.41 DDDs/100 patient-days). Conclusions: Here, we report the molecular epidemiology of LRSE in an ICU. Our results suggest the selection of resistant mutants under linezolid treatment as well as the spread of cfr-carrying plasmids. The reduction of linezolid usage and the strengthening of contact precautions proved to be effective infection control measures.
Assuntos
Antibacterianos/farmacologia , Infecção Hospitalar/epidemiologia , Farmacorresistência Bacteriana , Controle de Infecções/métodos , Linezolida/farmacologia , Infecções Estafilocócicas/epidemiologia , Staphylococcus epidermidis/efeitos dos fármacos , Idoso , Idoso de 80 Anos ou mais , Proteínas de Bactérias/genética , Infecção Hospitalar/prevenção & controle , Surtos de Doenças , Transmissão de Doença Infecciosa/prevenção & controle , Feminino , Genótipo , Alemanha , Humanos , Unidades de Terapia Intensiva , Masculino , Pessoa de Meia-Idade , Epidemiologia Molecular , RNA Ribossômico 23S/genética , Análise de Sequência de DNA , Infecções Estafilocócicas/microbiologia , Infecções Estafilocócicas/prevenção & controle , Staphylococcus epidermidis/classificação , Staphylococcus epidermidis/genética , Staphylococcus epidermidis/isolamento & purificaçãoRESUMO
Objectives: We present the results of two European external quality assessments (EQAs) conducted in 2014 and 2016 under the auspices of the Study Group on Staphylococci and Staphylococcal Infections of ESCMID. The objective was to assess the performance of participating centres in characterizing Staphylococcus aureus using their standard in-house phenotypic and genotypic protocols. Methods: A total of 11 well-characterized blindly coded S. aureus (n = 9), Staphylococcus argenteus (n = 1) and Staphylococcus capitis (n = 1) strains were distributed to participants for analysis. Species identification, MIC determination, antimicrobial susceptibility testing, antimicrobial resistance and toxin gene detection and molecular typing including spa typing, SCCmec typing and MLST were performed. Results: Thirteen laboratories from 12 European countries participated in one EQA or both EQAs. Despite considerable diversity in the methods employed, good concordance (90%-100%) with expected results was obtained. Discrepancies were observed for: (i) identification of the S. argenteus strain; (ii) phenotypic detection of low-level resistance to oxacillin in the mecC-positive strain; (iii) phenotypic detection of the inducible MLSB strain; and (iv) WGS-based detection of some resistance and toxin genes. Conclusions: Overall, good concordance (90%-100%) with expected results was observed. In some instances, the accurate detection of resistance and toxin genes from WGS data proved problematic, highlighting the need for validated and internationally agreed-on bioinformatics pipelines before such techniques are implemented routinely by microbiology laboratories. We strongly recommend all national reference laboratories and laboratories acting as referral centres to participate in such EQA initiatives.
Assuntos
Técnicas de Tipagem Bacteriana/normas , Tipagem de Sequências Multilocus/normas , Garantia da Qualidade dos Cuidados de Saúde , Staphylococcus aureus/classificação , Antibacterianos/farmacologia , DNA Bacteriano/genética , Europa (Continente) , Genótipo , Humanos , Testes de Sensibilidade Microbiana , Oxacilina/farmacologia , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus/efeitos dos fármacosRESUMO
The natural habitats and potential reservoirs of the nosocomial pathogen Acinetobacter baumannii are poorly defined. Here, we put forth and tested the hypothesis of avian reservoirs of A. baumannii. We screened tracheal and rectal swab samples from livestock (chicken, geese) and wild birds (white stork nestlings) and isolated A. baumannii from 3% of sampled chicken (n = 220), 8% of geese (n = 40) and 25% of white stork nestlings (n = 661). Virulence of selected avian A. baumannii isolates was comparable to that of clinical isolates in the Galleria mellonella infection model. Whole genome sequencing revealed the close relationship of an antibiotic-susceptible chicken isolate from Germany with a multidrug-resistant human clinical isolate from China and additional linkages between livestock isolates and human clinical isolates related to international clonal lineages. Moreover, we identified stork isolates related to human clinical isolates from the United States. Multilocus sequence typing disclosed further kinship between avian and human isolates. Avian isolates do not form a distinct clade within the phylogeny of A. baumannii, instead they diverge into different lineages. Further, we provide evidence that A. baumannii is constantly present in the habitats occupied by storks. Collectively, our study suggests A. baumannii could be a zoonotic organism that may disseminate into livestock.
Assuntos
Infecções por Acinetobacter/microbiologia , Acinetobacter baumannii/classificação , Acinetobacter baumannii/genética , Galinhas/microbiologia , Reservatórios de Doenças/microbiologia , Gansos/microbiologia , Células A549 , Acinetobacter baumannii/isolamento & purificação , Animais , Antibacterianos , Sequência de Bases , Linhagem Celular , China , Infecção Hospitalar/microbiologia , Farmacorresistência Bacteriana Múltipla/genética , Genoma Bacteriano/genética , Alemanha , Hospitais , Humanos , Tipagem de Sequências Multilocus , Filogenia , Polônia , Análise de Sequência de DNA , Estados Unidos , Sequenciamento Completo do GenomaRESUMO
OBJECTIVES: MRSA remains a major cause of severe nosocomial infections and the increased use of vancomycin and daptomycin for MRSA treatment over the last decade has led to the isolation of MRSA strains with decreased daptomycin susceptibility. In addition, a growing number of MSSA isolates with reduced susceptibility to daptomycin have been described lately. Surveillance of the emergence of such a daptomycin-non-susceptible MSSA population requires prompt and reliable daptomycin susceptibility testing. Therefore, this work aimed to evaluate the ability of commonly used methods to detect daptomycin resistance in clinical microbiological laboratories. METHODS: We used commercially available manual and automated test systems, including VITEK® 2 and three gradient strip assays, in comparison with broth microdilution, to detect daptomycin resistance in a representative Staphylococcus aureus strain collection. RESULTS: We found high inter-assay concordance as well as congruence with the reference method. This is demonstrated by essential agreement between commercial test systems and reference broth microdilution ranging from 98.1% to 100% and by categorical agreement from 98.2% to 99.1%. Thus, all systems used were able to detect daptomycin non-susceptibility in MRSA and MSSA isolates. CONCLUSIONS: Our data indicate that routine laboratories are at limited risk of overlooking further daptomycin resistance development, as long as commercially available test systems are used according to the manufacturer's recommendations. However, laboratories must be aware of an increasing number of daptomycin-non-susceptible MSSA isolates, including those exhibiting elevated MICs of glycopeptides.
Assuntos
Antibacterianos/farmacologia , Daptomicina/farmacologia , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Staphylococcus aureus/efeitos dos fármacos , Automação Laboratorial , Infecção Hospitalar/microbiologia , Humanos , Testes de Sensibilidade Microbiana/instrumentação , Testes de Sensibilidade Microbiana/métodos , Testes de Sensibilidade Microbiana/normas , Kit de Reagentes para Diagnóstico , Infecções Estafilocócicas/microbiologia , Vancomicina/farmacologia , Resistência a VancomicinaRESUMO
Staphylococcus aureus (S. aureus) is a Gram-positive opportunistic pathogen that colonizes frequently and asymptomatically the anterior nares of humans and animals. It can cause different kinds of infections and is considered to be an important nosocomial pathogen. Nasal carriage of S. aureus can be permanent or intermittent and may build the reservoir for autogenous infections and cross-transmission to other individuals. Most of the studies on the epidemiology of S. aureus performed in the past were focused on the emergence and dissemination of methicillin-resistant Staphylococcus aureus (MRSA) in healthcare settings. There are, however, a number of more recent epidemiological studies have aimed at analysing carriage patterns over time in the community settings providing new insights on risk factors for colonization and important data for the development of strategies to prevent infections. This chapter aims to give a review of current epidemiological studies on S. aureus carriage patterns in the general community and put them into perspective with recent, yet unpublished, investigations on the S. aureus epidemiology in the general population in northern Germany.
Assuntos
Portador Sadio/microbiologia , Nariz/microbiologia , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus/isolamento & purificação , Farmacorresistência Bacteriana , Humanos , Características de Residência/estatística & dados numéricos , Infecções Estafilocócicas/epidemiologia , Staphylococcus aureus/classificação , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/genéticaRESUMO
The widespread use of antibiotics in association with high-density clinical care has driven the emergence of drug-resistant bacteria that are adapted to thrive in hospitalized patients. Of particular concern are globally disseminated methicillin-resistant Staphylococcus aureus (MRSA) clones that cause outbreaks and epidemics associated with health care. The most rapidly spreading and tenacious health-care-associated clone in Europe currently is EMRSA-15, which was first detected in the UK in the early 1990s and subsequently spread throughout Europe and beyond. Using phylogenomic methods to analyze the genome sequences for 193 S. aureus isolates, we were able to show that the current pandemic population of EMRSA-15 descends from a health-care-associated MRSA epidemic that spread throughout England in the 1980s, which had itself previously emerged from a primarily community-associated methicillin-sensitive population. The emergence of fluoroquinolone resistance in this EMRSA-15 subclone in the English Midlands during the mid-1980s appears to have played a key role in triggering pandemic spread, and occurred shortly after the first clinical trials of this drug. Genome-based coalescence analysis estimated that the population of this subclone over the last 20 yr has grown four times faster than its progenitor. Using comparative genomic analysis we identified the molecular genetic basis of 99.8% of the antimicrobial resistance phenotypes of the isolates, highlighting the potential of pathogen genome sequencing as a diagnostic tool. We document the genetic changes associated with adaptation to the hospital environment and with increasing drug resistance over time, and how MRSA evolution likely has been influenced by country-specific drug use regimens.
Assuntos
Genoma Bacteriano , Staphylococcus aureus Resistente à Meticilina/genética , Infecções Estafilocócicas/epidemiologia , Análise por Conglomerados , Farmacorresistência Bacteriana/genética , Genômica , Genótipo , Humanos , Staphylococcus aureus Resistente à Meticilina/classificação , Pandemias , Filogenia , Filogeografia , Infecções Estafilocócicas/transmissão , Reino Unido/epidemiologiaRESUMO
Methicillin-resistant Staphylococcus aureus (MRSA) screening using real-time PCR has decreased in sensitivity due to the emergence of variant staphylococcal cassette chromosome mec element (SCCmec) types. We have designed and validated a novel SCCmec XI primer, which enables for the first time the rapid detection of mecC-harboring MRSA directly from nasopharyngeal swabs without prior cultivation.
Assuntos
Técnicas Bacteriológicas/métodos , Primers do DNA/genética , Programas de Rastreamento/métodos , Staphylococcus aureus Resistente à Meticilina/isolamento & purificação , Técnicas de Diagnóstico Molecular/métodos , Infecções Estafilocócicas/diagnóstico , Infecções Estafilocócicas/microbiologia , Portador Sadio/diagnóstico , Portador Sadio/microbiologia , Humanos , Staphylococcus aureus Resistente à Meticilina/genética , Nasofaringe/microbiologiaRESUMO
OBJECTIVES: This study was a detailed investigation of Staphylococcus epidermidis clinical isolates exhibiting linezolid resistance. METHODS: Thirty-six linezolid-resistant S. epidermidis from eight German hospitals, including isolates from suspected hospital-associated outbreaks between January 2012 and April 2013, were analysed with respect to their antimicrobial susceptibility and the presence of cfr and/or mutations in the 23S rRNA, rplC, rplD and rplV genes. Relatedness of isolates was estimated by MLST and SmaI macrorestriction analysis. Characterization of cfr plasmids was carried out by means of Illumina sequencing. RESULTS: The MICs of linezolid varied substantially between the isolates. No apparent correlation was detected between the level of resistance, the presence of cfr and ribosomal target site mutations. S. epidermidis isolates from two hospitals were confirmed as clonally related, indicating the spread of the respective clone over a period of 1 year. Next-generation sequencing revealed two different categories of cfr-expressing plasmids, both of them varying in genetic arrangement and composition from previously published cfr plasmids: p12-00322-like plasmids showed incorporation of cfr into a pGO1-like backbone and displayed capabilities for intra- and inter-species conjugational transfer. CONCLUSIONS: To date, linezolid-resistant S. epidermidis have rarely been isolated from human clinical sources in Germany. Here, we describe the emergence and outbreaks of these strains. We detected previously described and novel point mutations in the 23S ribosomal genes. The cfr gene was only present in six isolates. However, this is the first known description of cfr incorporation into conjugative vectors; under selective pressure, these vectors could give reasonable cause for concern.
Assuntos
Antibacterianos/farmacologia , Farmacorresistência Bacteriana , Linezolida/farmacologia , Plasmídeos , Infecções Estafilocócicas/epidemiologia , Staphylococcus epidermidis/efeitos dos fármacos , Antibacterianos/metabolismo , Surtos de Doenças , Genes Bacterianos , Genótipo , Alemanha , Hospitais , Humanos , Linezolida/metabolismo , Testes de Sensibilidade Microbiana , Tipagem de Sequências Multilocus , Polimorfismo de Fragmento de Restrição , Infecções Estafilocócicas/microbiologia , Staphylococcus epidermidis/classificação , Staphylococcus epidermidis/genéticaRESUMO
Outbreaks of Staphylococcus aureus are common in neonatal intensive care units (NICUs). Usually they are documented for methicillin-resistant strains, while reports involving methicillin-susceptible S. aureus (MSSA) strains are rare. In this study we report the epidemiological and molecular investigation of an MSSA outbreak in a NICU among preterm neonates. Infection control measures and interventions were commissioned by the Local Public Health Authority and supported by the Robert Koch Institute. To support epidemiological investigations molecular typing was done by spa-typing and Multilocus sequence typing; the relatedness of collected isolates was further elucidated by DNA SmaI-macrorestriction, microarray analysis and bacterial whole genome sequencing. A total of 213 neonates, 123 healthcare workers and 205 neonate parents were analyzed in the period November 2011 to November 2012. The outbreak strain was characterized as a MSSA spa-type t021, able to produce toxic shock syndrome toxin-1 and Enterotoxin A. We identified seventeen neonates (of which two died from toxic shock syndrome), four healthcare workers and three parents putatively involved in the outbreak. Whole-genome sequencing permitted to exclude unrelated cases from the outbreak and to discuss the role of healthcare workers as a reservoir of S. aureus on the NICU. Genome comparisons also indicated the presence of the respective clone on the ward months before the first colonized/infected neonates were detected.
Assuntos
Surtos de Doenças , Enterotoxinas/metabolismo , Tipagem Molecular , Infecções Estafilocócicas/epidemiologia , Staphylococcus aureus/classificação , Staphylococcus aureus/genética , Adulto , Toxinas Bacterianas , Feminino , Genótipo , Pessoal de Saúde , Humanos , Recém-Nascido , Unidades de Terapia Intensiva Neonatal , Epidemiologia Molecular , Pais , Análise de Sequência de DNA , Staphylococcus aureus/isolamento & purificação , SuperantígenosRESUMO
OBJECTIVES: To elucidate the evolutionary history of Staphylococcus aureus clonal complex (CC) 8, which encompasses several globally distributed epidemic lineages, including hospital-associated methicillin-resistant S. aureus (MRSA) and the highly prevalent community-associated MRSA clone USA300. METHODS: We reconstructed the phylogeny of S. aureus CC8 by mutation discovery at 112 genetic housekeeping loci from each of 174 isolates, sampled on five continents between 1957 and 2008. The distribution of antimicrobial resistance traits and of diverse mobile genetic elements was investigated in relation to the isolates' phylogeny. RESULTS: Our analyses revealed the existence of nine phylogenetic clades within CC8. We identified at least eight independent events of methicillin resistance acquisition in CC8 and dated the origin of a methicillin-resistant progenitor of the notorious USA300 clone to the mid-1970s. Of the S. aureus isolates in our collection, 88% carried plasmidic rep gene sequences, with up to five different rep genes in individual isolates and a total of eight rep families. Mapping the plasmid content onto the isolates' phylogeny illustrated the stable carriage over decades of some plasmids and the more volatile nature of others. Strikingly, we observed trends of increasing antibiotic resistance during the evolution of several lineages, including USA300. CONCLUSIONS: We propose a model for the evolution of S. aureus CC8, involving a split into at least nine phylogenetic lineages and a subsequent series of acquisitions and losses of mobile genetic elements that carry diverse virulence and antimicrobial resistance traits. The evolution of MRSA USA300 towards resistance to additional antibiotic classes is of major concern.
Assuntos
Farmacorresistência Bacteriana Múltipla , Evolução Molecular , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/genética , Filogenia , Infecções Estafilocócicas/microbiologia , Genótipo , Humanos , Sequências Repetitivas Dispersas , Staphylococcus aureus Resistente à Meticilina/classificação , Staphylococcus aureus Resistente à Meticilina/isolamento & purificaçãoRESUMO
OBJECTIVES: Co-trimoxazole (trimethoprim/sulfamethoxazole) is clinically valuable in treating skin and soft tissue infections (SSTIs) caused by community-associated methicillin-resistant Staphylococcus aureus (MRSA). The genetic basis of emerging trimethoprim/sulfamethoxazole resistance in S. aureus from Africa is unknown. Such knowledge is essential to anticipate its further spread. We investigated the molecular epidemiology of trimethoprim resistance in S. aureus collected in and imported from Africa. METHODS: Five hundred and ninety-eight human S. aureus isolates collected at five locations across sub-Saharan Africa [Gabon, Namibia, Nigeria (two) and Tanzania] and 47 isolates from travellers treated at six clinics in Europe because of SSTIs on return from Africa were tested for susceptibility to trimethoprim, sulfamethoxazole and trimethoprim/sulfamethoxazole, screened for genes mediating trimethoprim resistance in staphylococci [dfrA (dfrS1), dfrB, dfrG and dfrK] and assigned to spa genotypes and clonal complexes. RESULTS: In 313 clinical and 285 colonizing S. aureus from Africa, 54% of isolates were resistant to trimethoprim, 21% to sulfamethoxazole and 19% to trimethoprim/sulfamethoxazole. We found that 94% of trimethoprim resistance was mediated by the dfrG gene. Of the 47 S. aureus isolates from travellers with SSTIs, 27 (57%) were trimethoprim resistant and carried dfrG. Markers of trimethoprim resistance other than dfrG were rare. The presence of dfrG genes in S. aureus was neither geographically nor clonally restricted. CONCLUSIONS: dfrG, previously perceived to be an uncommon cause of trimethoprim resistance in human S. aureus, is widespread in Africa and abundant in imported S. aureus from ill returning travellers. These findings may foreshadow the loss of trimethoprim/sulfamethoxazole for the empirical treatment of SSTIs caused by community-associated MRSA.
Assuntos
Antibacterianos/farmacologia , Genes Bacterianos , Infecções Estafilocócicas/microbiologia , Infecções Estafilocócicas/transmissão , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/genética , Resistência a Trimetoprima , Adulto , África Subsaariana , DNA Bacteriano/genética , Europa (Continente) , Humanos , Testes de Sensibilidade Microbiana , Epidemiologia Molecular , Tipagem Molecular , Infecções dos Tecidos Moles/microbiologia , Infecções dos Tecidos Moles/transmissão , Staphylococcus aureus/classificação , Staphylococcus aureus/isolamento & purificação , ViagemRESUMO
Frequency, persistence and molecular characteristics of multidrug resistant bacteria colonizing inhabitants of long term care facilities are topics of current concern. We performed a point-prevalence survey of 402 residents in 7 elderly care facilities in Berlin, Germany. Inguinal swabs were analyzed for the presence of methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococci (VRE), and multidrug-resistant gram-negative bacteria. Three and six months following the initial investigation, all colonized residents were sampled again and the occurrence of intercurrent infections, hospital admissions and use of antimicrobials were registered. Genetic relatedness of the bacteria was investigated using multi-locus sequence typing (MLST), spa-typing and SmaI/XbaI-macrorestriction analysis. 33 (8.2%) residents were skin-colonized with multidrug-resistant bacteria. MRSA were found in 19 (4.7%) and ESBL-producing Enterobacteriaceae in 16 residents (3.98%). Independent risk factors for colonization with multidrug-resistant bacteria were a high level of care and the presence of chronic wounds. A large proportion of the observed bacteria persisted up to six months and showed a high degree of inter-individual diversity. Outcome analysis revealed that infections tend to occur slightly more often in residents colonized by multiresistant pathogens. We assume that a perceptible population of residents in nursing homes is at risk for individual colonization with multidrug-resistant bacteria as well as healthcare associated infections.
Assuntos
Portador Sadio/epidemiologia , Portador Sadio/microbiologia , Farmacorresistência Bacteriana Múltipla , Enterobacteriaceae/isolamento & purificação , Staphylococcus aureus Resistente à Meticilina/isolamento & purificação , Pele/microbiologia , Enterococos Resistentes à Vancomicina/isolamento & purificação , Idoso , Idoso de 80 Anos ou mais , Berlim/epidemiologia , Estudos Transversais , Enterobacteriaceae/classificação , Enterobacteriaceae/genética , Feminino , Instalações de Saúde , Humanos , Masculino , Staphylococcus aureus Resistente à Meticilina/classificação , Staphylococcus aureus Resistente à Meticilina/genética , Tipagem Molecular , Enterococos Resistentes à Vancomicina/classificação , Enterococos Resistentes à Vancomicina/genéticaAssuntos
Antineoplásicos/uso terapêutico , Exfoliatinas/metabolismo , Hospedeiro Imunocomprometido , Leucemia Linfocítica Crônica de Células B/tratamento farmacológico , Infecções Oportunistas/microbiologia , Pirazóis/uso terapêutico , Pirimidinas/uso terapêutico , Síndrome da Pele Escaldada Estafilocócica/microbiologia , Staphylococcus aureus/metabolismo , Adenina/análogos & derivados , Antibacterianos/administração & dosagem , Biópsia , Feminino , Humanos , Infusões Intravenosas , Leucemia Linfocítica Crônica de Células B/diagnóstico , Leucemia Linfocítica Crônica de Células B/imunologia , Pessoa de Meia-Idade , Infecções Oportunistas/diagnóstico , Infecções Oportunistas/imunologia , Piperidinas , Síndrome da Pele Escaldada Estafilocócica/diagnóstico , Síndrome da Pele Escaldada Estafilocócica/imunologia , Staphylococcus aureus/isolamento & purificação , Staphylococcus aureus/patogenicidade , Resultado do TratamentoRESUMO
BACKGROUND: Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) seem to be highly transmissible, often infect otherwise healthy humans and frequently occur in hospital outbreaks. METHODS: Refugees, living in accommodations in Germany were screened for nasal carriage of S. aureus. The isolates were investigated regarding resistance and virulence, phenotypically and by whole genome data analysis. RESULTS: 5.6% (9/161) of the refugees are carriers of S. aureus. 2.5% (4/161) are MRSA carriers. Among the refugees, spa-types t021, t084, t304, t991 and t4983 were detected, as well as the new spa-types t18794 and t18795. t304 and t991 are assumed to be local spa-types from the middle east. The isolates are less resistant and marginal biofilm formers. Each isolate has a remarkable set of virulence genes, although genes, encoding for proteins strongly associated with invasive S. aureus infections, like Panton-Valentine leucocidin, were not detected. CONCLUSION: The detection of strains from the middle east, supports the assumption that strains co-travel with the refugees and persist despite a transition of the host's living conditions. Whole genome data analysis does not permit to finally evaluate a germ's virulence. Nevertheless, an impression of the virulence potential of the strains, regarding skills in colonization, resistance, immune evasion, and host cell damaging can be pictured.
Assuntos
Staphylococcus aureus Resistente à Meticilina , Refugiados , Infecções Estafilocócicas , Antibacterianos , Humanos , Meticilina , Staphylococcus aureus Resistente à Meticilina/genética , Testes de Sensibilidade Microbiana , Infecções Estafilocócicas/epidemiologia , Staphylococcus aureus/genética , Virulência/genética , Fatores de Virulência/genéticaRESUMO
BACKGROUND: Since the 1990s, community-associated Methicillin-resistant Staphylococcus aureus (CA-MRSA) are described as emerging independent of health care. CA-MRSA is associated with the colonization and infection of healthy, immunocompetent younger individuals. While skin and soft tissue infections (SSTI) are predominant, life-threatening syndromes can also occur. METHODS: In this retrospective study, we investigated MRSA stains isolated from community-onset infections and from MRSA screening of children at admission to a tertiary-care hospital in 2012-2018. In total, 102 isolates were subjected to antibiotic susceptibility testing by broth microdilution, spa -typing, multilocus sequence typing, SCC mec typing and virulence/resistance gene detection by polymerase chain reaction. RESULTS: The majority of isolates originated from community-onset infections (80/102), of these primarily from SSTI (70/80). Additional strains were isolated by MRSA screening (22/102). In total 61.8% of the MRSA carried the gene for the Panton-Valentine leukocidin ( lukPV ). Molecular characterization of isolates revealed various epidemic MRSA clones, circulating in both community and hospital settings. Most prevalent epidemic lineages were isolates of the "European CA-MRSA clone" (CC80-MRSA-IV), the "Bengal Bay clone" (ST772-MRSA-V), or the "USA300 NAE clone" (ST8-MRSA-IVa). CONCLUSIONS: Our data highlight the importance of CA-MRSA causing SSTI in children. More frequent microbiological and molecular analysis of these strains is important for targeted treatment and can provide valuable data for molecular surveillance of the pathogen.
Assuntos
Infecções Comunitárias Adquiridas , Staphylococcus aureus Resistente à Meticilina , Infecções dos Tecidos Moles , Infecções Estafilocócicas , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Criança , Infecções Comunitárias Adquiridas/microbiologia , Exotoxinas/genética , Hospitais , Humanos , Leucocidinas/genética , Staphylococcus aureus Resistente à Meticilina/genética , Testes de Sensibilidade Microbiana , Estudos Retrospectivos , Infecções dos Tecidos Moles/microbiologia , Infecções Estafilocócicas/microbiologiaRESUMO
Tracing the spatial spread of pathogens is a key objective of molecular infectious disease epidemiology. Accordingly, a wide range of genotyping approaches have been used to monitor the dissemination of Staphylococcus aureus strains, from localized outbreaks to global spread. We provide a critical review of available methods, revealing that molecular markers currently in use for typing S. aureus acquire changes so slowly that they monitor evolutionary change over timescales that are largely irrelevant to epidemiology. Moreover, the more variable markers frequently do not reflect the pathogen's evolutionary history and, hence, provide potentially misleading information about spread. More recent work has demonstrated that staphylococcal evolution proceeds sufficiently fast that the dynamics of S. aureus spatial spread can be elucidated at great detail on the basis of genome-wide single-nucleotide polymorphisms.