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1.
Artigo em Inglês | MEDLINE | ID: mdl-31521811

RESUMO

BACKGROUND: Infectious pathogens harboring cephalosporin or fluoroquinolones resistance constitute a serious hazard to human health. OBJECTIVES: The aim of this study is to set up a methodology based on econometric analysis and largest European Union (EU) resistance database (EARS-Net) to model EU nosocomial antimicrobial resistance (AMR) and to detect tendency changes, steps or peaks. The contribution of legislation based on third generation cephalosporin (3GC) and fluoroquinolones (FQ) class referrals on EU resistance rate patterns is evaluated. METHODS: We studied 3GC and FQ resistance in nosocomial E. coli, K. pneumoniae and P. aeruginosa in at least 25 out of 30 EU countries (> 94% population coverage) weighted by their mean annual population between 2006 and 2016. Autoregressive and moving average integrated models (ARIMA) analysis inspired by Box-Jenkins methodology was thoroughly prepared to adjust series to a mathematic model to detect hypothetical changes in the general behavior. To the best of our knowledge, this is the first study using ARIMA with interventions to model overall EU nosocomial AMR data compiled in EARS-Net. RESULTS AND CONCLUSIONS: Econometric ARIMA model statistically proved slowdowns and reversions in increase trend of nosocomial E. coli and K. pneumoniae resistance to 3GC and FQ, as well as in resistance of P. aeruginosa resistance to 3GC. P. aeruginosa resistance to FQ shows a descending slope. These brakes and decreased trends proved constitute noteworthy milestones in tackling AMR in Europe.

2.
Artigo em Inglês | MEDLINE | ID: mdl-31109975

RESUMO

In 2012, a carbapenemase-producing Salmonella enterica serovar Corvallis isolate carrying a bla NDM-1 multiresistance IncA/C2 plasmid, apart from IncHI2 and ColE-like plasmids, was detected in a wild bird in Germany. In a recent broiler chicken infection study, we observed transfer of this bla NDM-1-carrying IncA/C2 plasmid to other Enterobacteriaceae Here, we focused on the stability of this plasmid and gained insight into the type and frequency of its structural alterations after an in vivo passage in a broiler chicken infection study.

3.
FEMS Microbiol Lett ; 365(17)2018 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-29982335

RESUMO

The Small World Initiative (SWI) and Tiny Earth are a consolidated and successful education programs rooted in the USA that tackle the antibiotic crisis by a crowdsourcing strategy. Based on active learning, it challenges young students to discover novel bioactive-producing microorganisms from environmental soil samples. Besides its pedagogical efficiency to impart microbiology content in academic curricula, SWI promotes vocations in research and development in Experimental Sciences and, at the same time, disseminates the antibiotic awareness guidelines of the World Health Organization. We have adapted the SWI program to the Spanish academic environment by a pioneering hierarchic strategy based on service-learning that involves two education levels (higher education and high school) with different degrees of responsibility. Throughout the academic year, 23 SWI teams, each consisting of 3-7 undergraduate students led by one faculty member, coordinated off-campus programs in 22 local high schools, involving 597 high school students as researchers. Post-survey-based evaluation of the program reveals a satisfactory achievement of goals: acquiring scientific abilities and general or personal competences by university students, as well as promoting academic decisions to inspire vocations for science- and technology-oriented degrees in younger students, and successfully communicating scientific culture in antimicrobial resistance to a young stratum of society.

4.
Microb Drug Resist ; 24(7): 1012-1019, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29920143

RESUMO

Carbapenem-resistant Acinetobacter baumannii (CRAB) infections are an increasing concern in intensive care units (ICUs) worldwide. The combination of carbapenemases and 16S rRNA-methyltransferases (16S-RMTases) further reduces the therapeutic options. OXA-carbapenemase/A. baumannii clone tandems in Latin America have already been described; however, no information exists in this region regarding the occurrence of 16S-RMTases in this microorganism. In addition, the epidemiology of A. baumannii in ICUs and its associated resistance profiles are poorly understood. Our objectives were as follows: to study the clonal relationship and antibiotic resistance profiles of clinical and digestive colonizing A. baumannii isolates in an ICU, to characterize the circulating carbapenemases, and to detect 16S-RMTases. Patients admitted between August 2010 and July 2011 with a clinically predicted hospital stay > 48 hr were included. Pharyngeal and rectal swabs were obtained during the first fortnight after hospitalization. Resistance profiles were determined with MicroScan® and VITEK2 system. Carbapenemases and 16S-RMTases were identified by PCR and sequencing, and clonality was assessed by pulsed-field gel electrophoresis and multilocus sequence typing. Sixty-nine patients were studied and 63 were diagnosed with bacterial infections. Among these, 29 were CRAB isolates; 49 A. baumannii were isolated as digestive colonizers. These 78 isolates were clustered in 7 pulsetypes, mostly belonging to ST79. The only carbapenemase genes detected were blaOXA-51 (n = 78), blaOXA-23 (n = 62), and blaOXA-58 (n = 3). Interestingly, two clinical isolates harbored the rmtC 16S-RMTase gene. To the best of our knowledge, this is the first description of the presence of rmtC in A. baumannii.

5.
Front Microbiol ; 9: 469, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29615998

RESUMO

ColE1 plasmids are important vehicles for the spread of antibiotic resistance in the Enterobacteriaceae and Pasteurellaceae families of bacteria. Their monitoring is essential, as they harbor important resistant determinants in humans, animals and the environment. In this work, we have analyzed ColE1 replicons using bioinformatic and experimental approaches. First, we carried out a computational study examining the structure of different ColE1 plasmids deposited in databases. Bioinformatic analysis of these ColE1 replicons revealed a mosaic genetic structure consisting of a host-adapted conserved region responsible for the housekeeping functions of the plasmid, and a variable region encoding a wide variety of genes, including multiple antibiotic resistance determinants. From this exhaustive computational analysis we developed a new PCR-based technique, targeting a specific sequence in the conserved region, for the screening, capture and sequencing of these small plasmids, either specific for Enterobacteriaceae or specific for Pasteurellaceae. To validate this PCR-based system, we tested various collections of isolates from both bacterial families, finding that ColE1 replicons were not only highly prevalent in antibiotic-resistant isolates, but also present in susceptible bacteria. In Pasteurellaceae, ColE1 plasmids carried almost exclusively antibiotic resistance genes. In Enterobacteriaceae, these plasmids encoded a large range of traits, including not only antibiotic resistance determinants, but also a wide variety of genes, showing the huge genetic plasticity of these small replicons. Finally, we also used a metagenomic approach in order to validate this technique, performing this PCR system using total DNA extractions from fecal samples from poultry, turkeys, pigs and humans. Using Illumina sequencing of the PCR products we identified a great diversity of genes encoded by ColE1 replicons, including different antibiotic resistance determinants, supporting the previous results achieved with the collections of bacterial isolates. In addition, we detected cryptic ColE1 plasmids in both families with no known genes in their variable region, which we have named sentinel plasmids. In conclusion, in this work we present a useful genetic tool for the detection and analysis of ColE1 plasmids, and confirm their important role in the dissemination of antibiotic resistance, especially in the Pasteurellaceae family of bacteria.

6.
Artigo em Inglês | MEDLINE | ID: mdl-29437622

RESUMO

The emergence and spread of carbapenemase-producing Enterobacteriaceae (CPE) in wildlife and livestock animals pose an important safety concern for public health. With our in vivo broiler chicken infection study, we investigated the transfer and experimental microevolution of the blaNDM-1-carrying IncA/C2 plasmid (pRH-1238) introduced by avian native Salmonella enterica subsp. enterica serovar Corvallis without inducing antibiotic selection pressure. We evaluated the dependency of the time point of inoculation on donor (S Corvallis [12-SA01738]) and plasmid-free Salmonella recipient [d-tartrate-fermenting (d-Ta+) S Paratyphi B (13-SA01617), referred to here as S Paratyphi B (d-Ta+)] excretion by quantifying their excretion dynamics. Using plasmid profiling by S1 nuclease-restricted pulsed-field gel electrophoresis, we gained insight into the variability of the native plasmid content among S Corvallis reisolates as well as plasmid acquisition in S Paratyphi B (d-Ta+) and the enterobacterial gut microflora. Whole-genome sequencing enabled us to gain an in-depth insight into the microevolution of plasmid pRH-1238 in S Corvallis and enterobacterial recipient isolates. Our study revealed that the fecal excretion of avian native carbapenemase-producing S Corvallis is significantly higher than that of S Paratyphi (d-Ta+) and is not hampered by S Paratyphi (d-Ta+). Acquisition of pRH-1238 in other Enterobacteriaceae and several events of plasmid pRH-1238 transfer to different Escherichia coli sequence types and Klebsiella pneumoniae demonstrated an interspecies broad host range. Regardless of the microevolutionary structural deletions in pRH-1238, the single carbapenem resistance marker blaNDM-1 was maintained on pRH-1238 throughout the trial. Furthermore, we showed the importance of the gut E. coli population as a vector of pRH-1238. In a potential scenario of the introduction of NDM-1-producing S Corvallis into a broiler flock, the pRH-1238 plasmid could persist and spread to a broad host range even in the absence of antibiotic pressure.

7.
Microbiome ; 6(1): 11, 2018 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-29335005

RESUMO

BACKGROUND: Antimicrobial resistance is a major global health challenge. Metagenomics allows analyzing the presence and dynamics of "resistomes" (the ensemble of genes encoding antimicrobial resistance in a given microbiome) in disparate microbial ecosystems. However, the low sensitivity and specificity of available metagenomic methods preclude the detection of minority populations (often present below their detection threshold) and/or the identification of allelic variants that differ in the resulting phenotype. Here, we describe a novel strategy that combines targeted metagenomics using last generation in-solution capture platforms, with novel bioinformatics tools to establish a standardized framework that allows both quantitative and qualitative analyses of resistomes. METHODS: We developed ResCap, a targeted sequence capture platform based on SeqCapEZ (NimbleGene) technology, which includes probes for 8667 canonical resistance genes (7963 antibiotic resistance genes and 704 genes conferring resistance to metals or biocides), and 2517 relaxase genes (plasmid markers) and 78,600 genes homologous to the previous identified targets (47,806 for antibiotics and 30,794 for biocides or metals). Its performance was compared with metagenomic shotgun sequencing (MSS) for 17 fecal samples (9 humans, 8 swine). ResCap significantly improves MSS to detect "gene abundance" (from 2.0 to 83.2%) and "gene diversity" (26 versus 14.9 genes unequivocally detected per sample per million of reads; the number of reads unequivocally mapped increasing up to 300-fold by using ResCap), which were calculated using novel bioinformatic tools. ResCap also facilitated the analysis of novel genes potentially involved in the resistance to antibiotics, metals, biocides, or any combination thereof. CONCLUSIONS: ResCap, the first targeted sequence capture, specifically developed to analyze resistomes, greatly enhances the sensitivity and specificity of available metagenomic methods and offers the possibility to analyze genes related to the selection and transfer of antimicrobial resistance (biocides, heavy metals, plasmids). The model opens the possibility to study other complex microbial systems in which minority populations play a relevant role.


Assuntos
Biologia Computacional/métodos , Resistência Microbiana a Medicamentos , Metagenômica/métodos , Animais , Sondas de DNA/genética , Fezes , Genes Bacterianos , Humanos , Suínos
9.
Microb Drug Resist ; 24(6): 792-798, 2018 Jul/Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29058515

RESUMO

New Delhi metallo-beta-lactamase (NDM)-mediated carbapenem resistance in Pseudomonas aeruginosa and Acinetobacter baumannii is a major concern. We investigated the presence of NDM and its variants in P. aeruginosa and A. baumannii at a tertiary hospital in North India. A total of 236 isolates (130 P. aeruginosa and 106 A. baumannii) were included; 38 (29.23%) P. aeruginosa and 20 A. baumannii isolates (18.8%) were resistant to carbapenems and all of them were blaNDM positive. All 38 carbapenem-resistant P. aeruginosa harbored blaNDM-1, while 12 (60%) of 20 A. baumannii harbored blaNDM-2. Pulsed-field gel electrophoresis showed that all 58 isolates were clonally unrelated. By Southern blot analysis, blaNDM-2 was located on chromosome. The blaNDM-2-positive isolates were more frequently recovered from tracheal aspirate (67% vs.16%; p = 0.02) and intensive care unit (67% vs. 20%; p = 0.001) than blaNDM-1. Among other carbapenemases, VIM was significantly associated with blaNDM-1 than blaNDM-2 (61% vs. 17%; p = 0.006). Mortality between blaNDM-1- and blaNDM-2-infected patients was comparable. When expressed in Escherichia coli, blaNDM-2 transformant conferred one doubling dilution higher MIC value for cefotaxime, piperacillin/tazobactam than blaNDM-1. The study shows the emergence of blaNDM-mediated resistance among P. aeruginosa and A. baumannii and rapid evolution of blaNDM-2 in A. baumannii with its chromosomal localization.


Assuntos
Acinetobacter baumannii/genética , Farmacorresistência Bacteriana Múltipla/genética , Pseudomonas aeruginosa/genética , beta-Lactamases/genética , Infecções por Acinetobacter/tratamento farmacológico , Infecções por Acinetobacter/microbiologia , Acinetobacter baumannii/efeitos dos fármacos , Antibacterianos/farmacologia , Proteínas de Bactérias/genética , Carbapenêmicos/farmacologia , Cromossomos Bacterianos/genética , Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Escherichia coli/genética , Feminino , Humanos , Índia , Masculino , Testes de Sensibilidade Microbiana/métodos , Pessoa de Meia-Idade , Prevalência , Infecções por Pseudomonas/tratamento farmacológico , Infecções por Pseudomonas/microbiologia , Pseudomonas aeruginosa/efeitos dos fármacos
10.
Int J Antimicrob Agents ; 49(6): 727-733, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28438568

RESUMO

Acinetobacter baumannii is a highly versatile nosocomial pathogen. Multidrug resistance among A. baumannii isolates led to the use of colistin, subsequently giving rise to colistin-resistant strains. In this study, the genetic and phenotypic profiles of two colistin-resistant A. baumannii isolates were investigated. Two A. baumannii isolates were obtained from Patient 1 (C071 and C440) and three isolates were obtained from Patient 2 (C080, C314 and C428). Susceptibility profiles were determined by VITEK®2 and Etest. Clonality was determined by RAPD analysis and trilocus multiplex PCR. The pmrCAB operon was sequenced and common carbapenemase genes were screened for by PCR. Doubling times, haemolysis, surface motility, biofilm formation, siderophore production and proteolytic activity were phenotypically determined. Finally, whole-genome sequencing was performed for all five isolates. Isolates C440 and C428 were resistant to colistin and were clonally identical to their sensitive counterparts. The cause of colistin resistance was traced to the previously described P233S mutation in pmrB of C440 and to a novel ΔI19 mutation in pmrB of C428. blaOXA-58-like and blaGES-5 from the strains of Patients 1 and 2, respectively, were also detected. C440 had attenuated proteolytic activity and was positive for siderophore production compared with C071. No difference in in vitro virulence was detected between isolates C080, C314 and C428. In conclusion, one common and one novel mutation were encountered in pmrB from two distinct colistin-resistant A. baumannii isolates. These mutations caused colistin resistance during therapy in two distinct clones, and only one of them had altered in vitro virulence.


Assuntos
Infecções por Acinetobacter/microbiologia , Acinetobacter baumannii/efeitos dos fármacos , Antibacterianos/farmacologia , Proteínas de Bactérias/genética , Colistina/farmacologia , Farmacorresistência Bacteriana , Mutação , Fatores de Transcrição/genética , Infecções por Acinetobacter/tratamento farmacológico , Acinetobacter baumannii/classificação , Acinetobacter baumannii/genética , Antibacterianos/uso terapêutico , Colistina/uso terapêutico , Humanos , Testes de Sensibilidade Microbiana , Tipagem Molecular , Reação em Cadeia da Polimerase Multiplex , Técnica de Amplificação ao Acaso de DNA Polimórfico , Virulência , beta-Lactamases/genética
11.
Artigo em Inglês | MEDLINE | ID: mdl-28396550

RESUMO

In this study, we characterized two tigecycline-resistant Klebsiella pneumoniae isolates from dog urine samples. The isolates were genetically unrelated, belonging to sequence type 11 (ST11) and ST147, both classically related to human isolates. To the best of our knowledge, this is the first identification of tigecycline-resistant isolates from animals. We unveil here the worrisome circulation among animals of bacterial clones resistant to this last-resort antibiotic.


Assuntos
Antibacterianos/farmacologia , Proteínas de Bactérias/metabolismo , Minociclina/análogos & derivados , Animais , Proteínas de Bactérias/genética , Farmacorresistência Bacteriana/genética , Humanos , Klebsiella pneumoniae/efeitos dos fármacos , Klebsiella pneumoniae/genética , Testes de Sensibilidade Microbiana , Minociclina/farmacologia , Tigeciclina
12.
Artigo em Inglês | MEDLINE | ID: mdl-27895020

RESUMO

ColE1 plasmids are small mobilizable replicons that play an important role in the spread of antibiotic resistance in Pasteurellaceae In this study, we describe how a natural single nucleotide polymorphism (SNP) near the origin of replication of the ColE1-type plasmid pB1000 found in a Pasteurella multocida clinical isolate generates two independent plasmid variants able to coexist in the same cell simultaneously. Using the Haemophilus influenzae Rd KW20 strain as a model system, we combined antibiotic susceptibility tests, quantitative PCRs, competition assays, and experimental evolution to characterize the consequences of the coexistence of the pB1000 plasmid variants. This coexistence produced an increase of the total plasmid copy number (PCN) in the host bacteria, leading to a rise in both the antibiotic resistance level and the metabolic burden produced by pB1000. Using experimental evolution, we showed that in the presence of ampicillin, the bacteria maintained both plasmid variants for 300 generations. In the absence of antibiotics, on the other hand, the bacteria are capable of reverting to the single-plasmid genotype via the loss of one of the plasmid variants. Our results revealed how a single mutation in plasmid pB1000 provides the bacterial host with a mechanism to increase the PCN and, consequently, the ampicillin resistance level. Crucially, this mechanism can be rapidly reversed to avoid the extra cost entailed by the increased PCN in the absence of antibiotics.


Assuntos
Farmacorresistência Bacteriana/genética , Pasteurella multocida/efeitos dos fármacos , Pasteurella multocida/genética , Ampicilina/farmacologia , Animais , Farmacorresistência Bacteriana/efeitos dos fármacos , Haemophilus influenzae/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Infecções por Pasteurella/microbiologia , Infecções por Pasteurella/veterinária , Pasteurella multocida/isolamento & purificação , Plasmídeos/efeitos dos fármacos , Polimorfismo de Nucleotídeo Único , Suínos
13.
Antimicrob Agents Chemother ; 60(10): 6356-8, 2016 10.
Artigo em Inglês | MEDLINE | ID: mdl-27431212

RESUMO

We studied the presence of the mobile colistin resistance gene mcr-1 in human, animal, and environmental Enterobacteriaceae samples from Cumana, Venezuela, that were collected in 2015. The mcr-1 gene was detected in 2/93 Escherichia coli isolates from swine (novel ST452) and human (ST19) samples that were resistant to colistin. Whole-genome sequencing and transformation experiments identified mcr-1 on an IncI2 plasmid. One of the isolates also bore the widely spread carbapenemase NDM-1. A One Health approach is necessary to further elucidate the flux of these high-risk genes.


Assuntos
Proteínas de Escherichia coli/genética , Escherichia coli/efeitos dos fármacos , Escherichia coli/isolamento & purificação , beta-Lactamases/genética , Animais , Colistina/farmacologia , Cães , Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Farmacorresistência Bacteriana Múltipla/genética , Escherichia coli/genética , Fezes/microbiologia , Humanos , Testes de Sensibilidade Microbiana , Aves Domésticas , Suínos , Venezuela
14.
Emerg Infect Dis ; 21(11): 2059-62, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26488937

RESUMO

We investigated 16S rRNA methyltransferases in 38 blaNDM-1-positive Pseudomonas aeruginosa isolates and found RmtC in 3 isolates, 1 of which also harbored RmtF. The isolates were clonally unrelated; rmtC and rmtF genes were located on a chromosome with the blaNDM-1 gene. Strategies are needed to limit the spread of such isolates.


Assuntos
Proteínas de Bactérias/genética , Farmacorresistência Bacteriana Múltipla/genética , Metiltransferases/genética , Pseudomonas aeruginosa/genética , RNA Ribossômico 16S/metabolismo , Antibacterianos/farmacologia , DNA Bacteriano , Regulação Bacteriana da Expressão Gênica , Humanos , Metiltransferases/metabolismo , Testes de Sensibilidade Microbiana , Dados de Sequência Molecular , Pseudomonas aeruginosa/efeitos dos fármacos , beta-Lactamases/metabolismo
15.
Antimicrob Agents Chemother ; 59(6): 3335-41, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25824216

RESUMO

Plasmids play a key role in the horizontal spread of antibiotic resistance determinants among bacterial pathogens. When an antibiotic resistance plasmid arrives in a new bacterial host, it produces a fitness cost, causing a competitive disadvantage for the plasmid-bearing bacterium in the absence of antibiotics. On the other hand, in the presence of antibiotics, the plasmid promotes the survival of the clone. The adaptations experienced by plasmid and bacterium in the presence of antibiotics during the first generations of coexistence will be crucial for the progress of the infection and the maintenance of plasmid-mediated resistance once the treatment is over. Here we developed a model system using the human pathogen Haemophilus influenzae carrying the small plasmid pB1000 conferring resistance to ß-lactam antibiotics to investigate host and plasmid adaptations in the course of a simulated ampicillin therapy. Our results proved that plasmid-bearing clones compensated for the fitness disadvantage during the first 100 generations of plasmid-host adaptation. In addition, ampicillin treatment was associated with an increase in pB1000 copy number. The augmentation in both bacterial fitness and plasmid copy number gave rise to H. influenzae populations with higher ampicillin resistance levels. In conclusion, we show here that the modulations in bacterial fitness and plasmid copy number help a plasmid-bearing bacterium to adapt during antibiotic therapy, promoting both the survival of the host and the spread of the plasmid.


Assuntos
Antibacterianos/farmacologia , Plasmídeos/genética , Variações do Número de Cópias de DNA/genética , Resistência Microbiana a Medicamentos/genética , Haemophilus influenzae/efeitos dos fármacos , Haemophilus influenzae/genética , Haemophilus influenzae/fisiologia
16.
Appl Environ Microbiol ; 81(9): 3255-67, 2015 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-25747001

RESUMO

Haemophilus parasuis, the causative agent of Glässer's disease, is one of the early colonizers of the nasal mucosa of piglets. It is prevalent in swine herds, and lesions associated with disease are fibrinous polyserositis and bronchopneumonia. Antibiotics are commonly used in disease control, and resistance to several antibiotics has been described in H. parasuis. Prediction of H. parasuis virulence is currently limited by our scarce understanding of its pathogenicity. Some genes have been associated with H. parasuis virulence, such as lsgB and group 1 vtaA, while biofilm growth has been associated with nonvirulent strains. In this study, 86 H. parasuis nasal isolates from farms that had not had a case of disease for more than 10 years were obtained by sampling piglets at weaning. Isolates were studied by enterobacterial repetitive intergenic consensus PCR and determination of the presence of lsgB and group 1 vtaA, biofilm formation, inflammatory cell response, and resistance to antibiotics. As part of the diversity encountered, a novel 2,661-bp plasmid, named pJMA-1, bearing the blaROB-1 ß-lactamase was detected in eight colonizing strains. pJMA-1 was shown to share a backbone with other small plasmids described in the Pasteurellaceae, to be 100% stable, and to have a lower biological cost than the previously described plasmid pB1000. pJMA-1 was also found in nine H. parasuis nasal strains from a separate collection, but it was not detected in isolates from the lesions of animals with Glässer's disease or in nontypeable Haemophilus influenzae isolates. Altogether, we show that commensal H. parasuis isolates represent a reservoir of ß-lactam resistance genes which can be transferred to pathogens or other bacteria.


Assuntos
Infecções por Haemophilus/veterinária , Haemophilus parasuis/enzimologia , Haemophilus parasuis/isolamento & purificação , Plasmídeos/isolamento & purificação , beta-Lactamases/metabolismo , Animais , Animais Recém-Nascidos , Antibacterianos/metabolismo , Portador Sadio/microbiologia , Portador Sadio/veterinária , DNA Bacteriano/química , DNA Bacteriano/genética , Infecções por Haemophilus/microbiologia , Haemophilus influenzae/genética , Haemophilus parasuis/genética , Dados de Sequência Molecular , Pasteurellaceae/genética , Análise de Sequência de DNA , Suínos , Desmame , Resistência beta-Lactâmica , beta-Lactamases/genética , beta-Lactamas/metabolismo
17.
Antimicrob Agents Chemother ; 59(5): 2898-900, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-25691629

RESUMO

The inactivation of the mgrB gene, which encodes a negative-feedback regulator of the PhoPQ signaling system, was recently shown to be a common mutational mechanism responsible for acquired polymyxin resistance among carbapenemase-producing Klebsiella pneumoniae strains from clinical sources. In this work, we show that mgrB mutants can easily be selected in vitro from different K. pneumoniae lineages, and mgrB inactivation is not associated with a significant biological cost.


Assuntos
Antibacterianos/farmacologia , Klebsiella pneumoniae/efeitos dos fármacos , Klebsiella pneumoniae/genética , Polimixinas/farmacologia , Infecções por Klebsiella/microbiologia , Testes de Sensibilidade Microbiana
18.
Insect Sci ; 22(2): 178-90, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24339348

RESUMO

Unlike other dung beetles, the Iberian geotrupid, Thorectes lusitanicus, exhibits polyphagous behavior; for example, it is able to eat acorns, fungi, fruits, and carrion in addition to the dung of different mammals. This adaptation to digest a wider diet has physiological and developmental advantages and requires key changes in the composition and diversity of the beetle's gut microbiota. In this study, we isolated aerobic, facultative anaerobic, and aerotolerant microbiota amenable to grow in culture from the gut contents of T. lusitanicus and resolved isolate identity to the species level by sequencing 16S rRNA gene fragments. Using BLAST similarity searches and maximum likelihood phylogenetic analyses, we were able to reveal that the analyzed fraction (culturable, aerobic, facultative anaerobic, and aerotolerant) of beetle gut microbiota is dominated by the phyla Proteobacteria, Firmicutes, and Actinobacteria. Among Proteobacteria, members of the order Enterobacteriales (Gammaproteobacteria) were the most abundant. The main functions associated with the bacteria found in the gut of T. lusitanicus would likely include nitrogen fixation, denitrification, detoxification, and diverse defensive roles against pathogens.


Assuntos
Bactérias/isolamento & purificação , Besouros/microbiologia , Animais , Bactérias/genética , Bactérias Aeróbias/genética , Bactérias Aeróbias/isolamento & purificação , Trato Gastrointestinal/microbiologia , Filogenia , RNA Ribossômico 16S/genética
19.
Int J Antimicrob Agents ; 44(1): 30-7, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24831713

RESUMO

The growing prevalence of carbapenem resistance in Enterobacteriaceae worldwide is a major concern. New Delhi metallo-ß-lactamase (NDM)-mediated carbapenem resistance has been identified in Enterobacteriaceae from numerous countries including those of the Indian subcontinent. Currently, seven NDM ß-lactamase variants (NDM-1 to -7) have been identified. This study evaluated the detection and molecular characterisation of NDM variants in Enterobacteriaceae at a tertiary care hospital in India. A total of 464 isolates were tested; 57 (12.3%) were resistant or showed reduced susceptibility to imipenem and meropenem. All carbapenem-resistant isolates were blaNDM-positive by PCR, but 13 isolates bore variants that differed in sequence from blaNDM-1. NDM-5, NDM-6 and NDM-7 were identified in two, eight and three isolates, respectively. blaNDM variants were located on plasmids of >100kb with IncF, IncA/C and untypeable replicon types. Genes encoding the 16S rRNA methyltransferases RmtB, RmtC and ArmA as well as those for AmpC ß-lactamases were also located on the same plasmids as blaNDM in different combinations. The prevalence of NDM-5 to -7 variants was significantly higher in Escherichia coli (P=0.015) and they were more frequently isolated from the urology ward (P=0.037) than NDM-1. The mortality rate was comparable between patients infected with isolates positive for blaNDM-1 and blaNDM variants [25% (11/44) vs. 23% (3/13)]. Expression of blaNDM variants in E. coli using the same promoter showed that NDM-7 conferred higher resistance to imipenem. The diverse genotypic features of blaNDM indicate rapid evolution of NDM resulting from their wide spread in the Indian subcontinent.


Assuntos
Farmacorresistência Bacteriana Múltipla/genética , Infecções por Enterobacteriaceae/tratamento farmacológico , Enterobacteriaceae/genética , Regulação Bacteriana da Expressão Gênica , Plasmídeos/metabolismo , beta-Lactamases/genética , Adulto , Idoso , Antibacterianos/uso terapêutico , Pré-Escolar , Enterobacteriaceae/efeitos dos fármacos , Enterobacteriaceae/enzimologia , Enterobacteriaceae/crescimento & desenvolvimento , Infecções por Enterobacteriaceae/microbiologia , Infecções por Enterobacteriaceae/mortalidade , Feminino , Humanos , Índia , Isoenzimas/genética , Isoenzimas/metabolismo , Masculino , Metiltransferases/genética , Metiltransferases/metabolismo , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , Tipagem de Sequências Multilocus , Análise de Sobrevida , Centros de Atenção Terciária , beta-Lactamases/metabolismo , beta-Lactamas/uso terapêutico
20.
J Infect Dev Ctries ; 7(10): 691-5, 2013 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-24129620

RESUMO

INTRODUCTION: Salmonella infections are increasing worldwide, but there are few reports on Salmonella surveillance in African countries and other developing countries. This has made it difficult to estimate the actual burden of salmonellosis, especially in Africa. This study was conducted in a neglected Northern Region of Ghana where there are no previous data on Salmonella serotypes. METHODOLOGY: Standard microbiological tests were used for isolation, identification, and serotyping. Micro-dilution was used for the antimicrobial susceptibility tests. RESULTS: Four serotypes of Salmonella were identified: S. Urbana, S. Ouakam, S. Senftenberg, and S. Stanleyville. All the serotypes were susceptible to the 20 antibiotics used in the susceptibility test. S. Urbana and S. Ouakam were identified in humans for the first time in Africa. CONCLUSION: This study may serve as a baseline study for future investigations on Salmonella in the region and may assist public health officials to take the appropriate measures in case of a disease outbreak caused by Salmonella in the area. The article may also give health officials a fair idea of the resistance level of these serotypes in the region.


Assuntos
Infecções por Salmonella/epidemiologia , Infecções por Salmonella/microbiologia , Salmonella/isolamento & purificação , Antibacterianos/farmacologia , Coleta de Dados , Gana/epidemiologia , Humanos , Testes de Sensibilidade Microbiana , Sorotipagem
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