RESUMO
Few reports described infections with CC398 methicillin-susceptible Staphylococcus aureus (MSSA). We compared the genetic background of CC398 MSSA strains from nasal carriage and knee arthroplasty infection. DNA microarray analysis shows acquisition of particular adhesin, iron capture system and immune defense evasion mechanisms. These characteristics could explain pathogenesis in this type of infection.
Assuntos
Portador Sadio/microbiologia , Cavidade Nasal/microbiologia , Infecções Relacionadas à Prótese/microbiologia , Staphylococcus aureus/isolamento & purificação , Adulto , Idoso , Idoso de 80 Anos ou mais , Agricultura , DNA Bacteriano/análise , DNA Bacteriano/genética , Feminino , França , Humanos , Masculino , Staphylococcus aureus Resistente à Meticilina , Pessoa de Meia-Idade , Staphylococcus aureus/classificação , Staphylococcus aureus/genética , Adulto JovemRESUMO
A Proteus mirabilis clinical strain (7001324) was isolated from urine sample of a patient hospitalized in a long-term-care facility. PCR and cloning experiments performed with this strain identified a novel TEM-type ß-lactamase (TEM-187) differing by four amino acid substitutions (Leu21Phe, Arg164His, Ala184Val, and Thr265Met) from TEM-1. This characterization provides further evidence for the diversity of extended-spectrum ß-lactamases (ESBL) produced by P. mirabilis and for their potential spread to other Enterobacteriaceae due to a lack of sensitive detection methods used in daily practice.
Assuntos
Antibacterianos/farmacologia , Farmacorresistência Bacteriana Múltipla/genética , Proteus mirabilis/efeitos dos fármacos , beta-Lactamases/genética , Substituição de Aminoácidos , Sequência de Bases , Humanos , Testes de Sensibilidade Microbiana , Dados de Sequência Molecular , Infecções por Proteus/tratamento farmacológico , Infecções por Proteus/microbiologia , Proteus mirabilis/enzimologia , Proteus mirabilis/genética , Proteus mirabilis/isolamento & purificação , beta-Lactamases/metabolismoRESUMO
We describe the first case of bacteremia due to Gallibacterium anatis. The patient, a 26-year-old woman, developed bacteremia and diarrhea. The origin of infection was possibly due to a diet contaminated by G. anatis in this highly immunocompromised patient.
Assuntos
Bacteriemia/diagnóstico , Bacteriemia/microbiologia , Infecções por Pasteurellaceae/diagnóstico , Infecções por Pasteurellaceae/microbiologia , Pasteurellaceae/isolamento & purificação , Adulto , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Diarreia/diagnóstico , Diarreia/microbiologia , Feminino , Doenças Transmitidas por Alimentos/diagnóstico , Doenças Transmitidas por Alimentos/microbiologia , Humanos , Hospedeiro Imunocomprometido , Dados de Sequência Molecular , Pasteurellaceae/classificação , Pasteurellaceae/genética , Infecções por Pasteurellaceae/complicações , RNA Ribossômico 16S/genética , Análise de Sequência de DNARESUMO
OBJECTIVES: This study reports details on Escherichia coli isolates recovered from a cystic fibrosis (CF) patient in order to understand how this pathogen adapts to and resists broad-spectrum antipseudomonal therapy in this context. METHODS: Five E. coli isolates were obtained from various clinical samples (airways, urine or dialysis catheter) over a 7 month period covering a double-lung transplantation. All isolates were analysed in terms of clonality [enterobacterial repetitive intergenic consensus (ERIC)-PCR and multilocus sequence typing], virulence profiles (phylogroup and search for 15 virulence genes), growth patterns (morphotype, biofilm-forming ability and growth rate), hypermutability and antimicrobial susceptibility, with molecular characterization of ß-lactamases and porins. RESULTS: The five isolates shared similar ERIC-PCR profiles and sequence types (ST1193) and exhibited the same virulence profile. The respiratory isolates were strong mutators, exhibited mucoid or small-colony morphotypes, exhibited strong biofilm-forming ability and grew slowly compared with the others. All isolates were highly resistant to ceftazidime. The respiratory isolates showed reduced susceptibility to cefepime and high resistance to aztreonam. The patient had received a 31 day course of ceftazidime/aztreonam until transplantation. All isolates harboured the same wild-type chromosomal AmpC. A CMY-2 enzyme was detected in the non-respiratory isolates. The respiratory isolates harboured L293S and V211A/L293S new CMY-2 variants, which were designated CMY-94 and CMY-95, respectively. OmpF porin loss was observed in the non-respiratory isolates. CONCLUSIONS: Our study shows that, similarly to Pseudomonas aeruginosa, E. coli can undergo phenotypic and genomic changes in the CF context. For the first time, we identified an in vivo expanded-spectrum evolution of the CMY-2 ß-lactamase, during bacterial persistence in the CF lung.
Assuntos
Fibrose Cística/complicações , Microbiologia Ambiental , Infecções por Escherichia coli/microbiologia , Escherichia coli/enzimologia , Escherichia coli/isolamento & purificação , beta-Lactamases/genética , Adaptação Biológica , Antibacterianos/farmacologia , Análise por Conglomerados , Escherichia coli/classificação , Escherichia coli/genética , Humanos , Testes de Sensibilidade Microbiana , Tipagem Molecular , Fatores de Virulência/genéticaRESUMO
Sternal osteitis, a potential consequence of cardiac surgery, remains rare. The bacteria involved belong mostly to the genus Staphylococcus. Sternal infections caused by Serratia marcescens are exceptional. We report an unusual recurrence of sternal infection with S. marcescens, 15 years after the initial episode. The identities of the isolates were determined by genomic analysis.
Assuntos
Osteíte/diagnóstico , Osteíte/microbiologia , Infecções por Serratia/diagnóstico , Infecções por Serratia/microbiologia , Serratia marcescens/isolamento & purificação , Análise por Conglomerados , DNA Bacteriano/genética , Eletroforese em Gel de Campo Pulsado , Genótipo , Humanos , Masculino , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , Tipagem Molecular , Osteíte/patologia , Recidiva , Infecções por Serratia/patologia , Esterno/microbiologia , Esterno/patologiaRESUMO
Twenty-one isolates of Staphylococcus epidermidis from 9 patients with persistent prosthetic joint infections were analysed by pulsed-field gel electrophoresis and antibiotic susceptibility assays. In 7 of these cases, the S. epidermidis isolate was different from that of the initial episode. In 1 further case, the superinfection was polyclonal. Recurrence, i.e., renewed isolation of a clone identical to that of an initial episode, occurred in 3 cases, 1 of which was in the absence of superinfection. A high degree of antibiotic resistance was demonstrated, including methicillin in 17 of 21 strains. In conclusion, a frequent occurrence of superinfection and a high degree of resistance make management of these infections complex.
Assuntos
Prótese Articular/microbiologia , Infecções Relacionadas à Prótese/microbiologia , Infecções Estafilocócicas/microbiologia , Staphylococcus epidermidis/isolamento & purificação , Idoso , Idoso de 80 Anos ou mais , Artroplastia de Quadril , Artroplastia do Joelho , Doença Crônica , Eletroforese em Gel de Campo Pulsado , Feminino , Humanos , Masculino , Recidiva , Estudos Retrospectivos , Fatores de Risco , Staphylococcus epidermidis/genética , Superinfecção/microbiologiaRESUMO
INTRODUCTION: We investigated the role of PI3-K, MAP kinases, and heterotrimeric G proteins in inducing cytokines production in human whole blood cultures stimulated by viable Escherichia coli (E. coli) clinical strains. MATERIALS AND METHODS: We used eight E. coli strains that belong to different phylogenetic groups and presented by different antibiotic resistance patterns. Whole blood from healthy volunteers was incubated at 37°C for 150min, with lipopolysaccharide (LPS) from E. coli O111:B4 or selected viable E. coli clinical strains, with or without SB202190 (p38 inhibitor), PD98059 (ERK inhibitor), PTX (pertussis toxin; heterotrimeric G proteins inhibitor), wortmaninn (PI3-K inhibitor). The TNF-α, IL-1ß, IL-10 and IFN-γ concentrations were measured in culture supernatants (ELISA). RESULTS: IL-10 and IFN-γ were not detectable. Susceptible strains induced higher TNF-α and IL-1ß productions than ß-lactam resistant strains (p<0.05), with no difference between phylogenetic groups. A transformed strain carrying a plasmid-mediated AmpC-ß-lactamase gene (CMY-2) induced lower TNF-α and IL-1ß production than the parent wild type strain (p<0.05). SB202190 (p38 inhibitor) and PD98059 (ERK inhibitor) reduced TNF-α concentrations by, respectively, 80% (p<0.05) and 50% (p<0.05). Wortmaninn (PI3-K inhibitor) had no significant effect. PTX (heterotrimeric G proteins inhibitor) altered TNF-α production after viable bacteria stimulation (1.7-fold increase; p<0.05) but not after LPS (TLR-4) stimulation. Regarding IL-1ß, wortmaninn, SB202190 and PTX had no significant effect whereas PD98059 significantly decreased production in whole cell cultures (p<0.05). CONCLUSION: Susceptible strains induce greater TNF-α and IL-1ß productions than resistant strains. ERK kinase plays a major role in viable E. coli strains inducing TNF-α and IL-1ß production. E. coli exerts an effect on the pertussis toxin-sensitive G-protein through a TLR-4-independent mechanism.
Assuntos
Citocinas/biossíntese , Escherichia coli/fisiologia , Proteínas de Ligação ao GTP/metabolismo , Mediadores da Inflamação/metabolismo , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Filogenia , Proteínas Proto-Oncogênicas c-akt/metabolismo , Contagem de Colônia Microbiana , Farmacorresistência Bacteriana , Escherichia coli/classificação , Escherichia coli/efeitos dos fármacos , Feminino , Humanos , MasculinoRESUMO
Extended-spectrum AmpC beta-lactamase (ESAC) Escherichia coli producers were investigated over a 5-year period. Eleven isolates presenting a strong ampC promoter and different strategic AmpC mutations, including two newly described modifications (A292V and an L-A-A insertion at 295), were characterized. All the isolates belonged to phylogenetic group A and to the ST23 complex.
Assuntos
Proteínas de Bactérias/genética , Infecções por Escherichia coli/tratamento farmacológico , Proteínas de Escherichia coli/genética , Escherichia coli/genética , Filogenia , Resistência beta-Lactâmica/genética , beta-Lactamases/genética , Cefepima , Cefotaxima/farmacologia , Ceftazidima/farmacologia , Cefalosporinas/farmacologia , Escherichia coli/efeitos dos fármacos , Escherichia coli/enzimologia , Infecções por Escherichia coli/microbiologia , França , Hospitalização , Humanos , Dados de Sequência Molecular , Mutação , Regiões Promotoras Genéticas/genéticaRESUMO
Legionella pneumophila is an important cause of community-acquired and nosocomial pneumonia. We report on a patient who simultaneously developed L. pneumophila serogroup 8 pneumonia and Aspergillus fumigatus lung abscesses. Despite appropriate treatments, Aspergillus disease progressed with metastasis. Coinfections caused by L. pneumophila and A. fumigatus remain exceptional. In apparently immunocompetent patients, corticosteroid therapy is a key risk factor for aspergillosis.
Assuntos
Aspergilose/complicações , Aspergillus fumigatus/isolamento & purificação , Legionella pneumophila/isolamento & purificação , Doença dos Legionários/complicações , Aspergilose/tratamento farmacológico , Evolução Fatal , Humanos , Legionella pneumophila/classificação , Doença dos Legionários/tratamento farmacológico , Abscesso Pulmonar/microbiologia , Masculino , Pessoa de Meia-Idade , Radiografia Torácica , Tomografia Computadorizada por Raios XRESUMO
We developed a quantitative real-time PCR assay targeting the mip gene of Legionella pneumophila for a prospective study from September 2004 to April 2005. It was compared with a standard culture method (French guideline AFNOR T90-431), analysing 120 water samples collected to monitor the risk related to Legionellae at Nantes hospital and to investigate a case of legionellosis acquired from hospital environment. Samples from six distinct water distribution systems were analysed by DNA extraction, amplification and detection with specific primers and FRET probes. The detection limit was 100 genomic units of L. pneumophila per liter (GU/l), the positivity threshold about 600 GU/l and the quantification limit 800 GU/l. PCR results were divided into three groups: negative (n=63), positive but non-quantifiable (n=22) or positive (n=35). PCR showed higher sensitivity than culture, whereas four culture-positive samples appeared negative by PCR (PCR inhibitor detected for two of them). Although no correlation was observed between both methods and real-time PCR cannot substitute for the reference method, it represents an interesting complement. Its sensitivity, reproducibility and rapidity appear particularly interesting in epidemic contexts in order to identify the source of contamination or to evaluate critical points of contamination in water distribution systems.
Assuntos
Legionella pneumophila/isolamento & purificação , Reação em Cadeia da Polimerase/métodos , Microbiologia da Água , Abastecimento de Água/análise , Idoso , Proteínas de Bactérias/genética , Contagem de Colônia Microbiana , Infecção Hospitalar/microbiologia , Infecção Hospitalar/prevenção & controle , Técnicas de Cultura , Sondas de DNA , DNA Bacteriano/isolamento & purificação , Surtos de Doenças/prevenção & controle , França , Hospitais , Humanos , Legionella pneumophila/genética , Doença dos Legionários/microbiologia , Doença dos Legionários/prevenção & controle , Masculino , Peptidilprolil Isomerase/genéticaAssuntos
Carbapenêmicos/farmacologia , Infecção Hospitalar/epidemiologia , Surtos de Doenças , Enterobacter cloacae/isolamento & purificação , Infecções por Enterobacteriaceae/epidemiologia , Resistência beta-Lactâmica , beta-Lactamases/genética , Idoso , Antibacterianos/farmacologia , Infecção Hospitalar/microbiologia , Enterobacter cloacae/efeitos dos fármacos , Infecções por Enterobacteriaceae/microbiologia , Trato Gastrointestinal/microbiologia , Transferência Genética Horizontal , Humanos , Testes de Sensibilidade Microbiana , beta-Lactamas/farmacologiaRESUMO
Two hundred and five isolates of Klebsiella pneumoniae were collected from Nantes University Hospital in 2002. A new 30bp deletion was detected downstream of the -10 box of the SHV-1 promoter in a clinical K. pneumoniae isolate with a high amoxicillin/clavulanic acid minimum inhibitory concentration. Reverse transcription polymerase chain reaction revealed increased transcription of bla(SHV-1) mRNA. All conjugation mating assays failed. This new promoter was cloned upstream of the cat gene of the reporter plasmid pKK232-8 and compared with previously described bla(SHV-1) promoters. The deletion induced a 15-fold increase in promoter strength compared with the usual weak promoter. This study reports a new genetic event that increases bla(SHV-1) chromosomal gene expression, which may be of clinical relevance when associated with porin deficiency.
Assuntos
Deleção de Genes , Klebsiella pneumoniae/efeitos dos fármacos , Regiões Promotoras Genéticas , Resistência beta-Lactâmica/genética , beta-Lactamases/metabolismo , beta-Lactamas/farmacologia , DNA Bacteriano/análise , Farmacorresistência Bacteriana/genética , Regulação Bacteriana da Expressão Gênica/efeitos dos fármacos , Infecções por Klebsiella , Klebsiella pneumoniae/enzimologia , Klebsiella pneumoniae/genética , Klebsiella pneumoniae/metabolismo , Testes de Sensibilidade Microbiana , Plasmídeos/genética , beta-Lactamases/genéticaRESUMO
Tetracyclines and macrolide antibiotics have been in use for acne treatment for more than 20 years. Since 1992 increasing resistance to these antibiotics, and especially to erythromycin, is reported with Propionibacterium acnes. Zinc salts have demonstrated their efficacy in inflammatory acne treatment as well as their bacteriostatic activity against Propionibacterium acnes. The objective of our work was firstly to determine whether the clinical anti-inflammatory efficacy of zinc salts was altered in the presence of erythromycin resistant strains in vivo, and secondly to study the in vitro and in vivo effect of zinc on the sensitivity of Propionibacterium acnes strains to erythromycin. Thirty patients with inflammatory acne were treated by zinc gluconate with a daily dose of 30 mg for two months and bacteriologic samples were taken at D0, D30 and D60. In vivo, this study displayed a reduction in the number of inflammatory lesions after a 2-month treatment whether or not Propionibacterium acnes carriage was present. Concurrently, in vitro addition of zinc salts in the culture media of Propionibacterium acnes reduced resistance of Propionibacterium acnes strains to erythromycin. Thus, association of zinc salts via a systemic route and topical erythromycin treatment seems an interesting option in the light of an increasing number of patients carrying erythromycin resistant Propionibacterium acnes strains.
Assuntos
Acne Vulgar/tratamento farmacológico , Acne Vulgar/microbiologia , Eritromicina/uso terapêutico , Gluconatos/uso terapêutico , Propionibacterium acnes/efeitos dos fármacos , Acne Vulgar/patologia , Administração Oral , Adolescente , Adulto , Criança , Relação Dose-Resposta a Droga , Esquema de Medicação , Farmacorresistência Bacteriana , Eritromicina/farmacologia , Feminino , Seguimentos , Humanos , Masculino , Testes de Sensibilidade Microbiana , Probabilidade , Propionibacterium acnes/isolamento & purificação , Medição de Risco , Estudos de Amostragem , Índice de Gravidade de Doença , Resultado do TratamentoRESUMO
To understand the regulation of the MexAB OprM efflux system in a clinical strain of Pseudomonas aeruginosa presenting a decreased susceptibility to ticarcillin and aztreonam, the mexR repressor gene was amplified by polymerase chain reaction (PCR) and was shown to be disrupted by an insertion sequence of more than 2 kb, with characteristic direct and inverted repeat sequences. Sequencing revealed a 2131-bp IS21 insertion sequence. A reverse transcription PCR method was used to quantify mexA transcripts and showed an increased transcription rate of mexA in this strain, compared with a PAO1 control strain. The nalB phenotype in P. aeruginosa may be due to point mutations, but also to the presence of an insertion sequence in the mexR regulator gene.
Assuntos
Proteínas de Bactérias , Elementos de DNA Transponíveis/genética , Regulação Bacteriana da Expressão Gênica , Pseudomonas aeruginosa/efeitos dos fármacos , Proteínas Repressoras/genética , Resistência beta-Lactâmica/genética , Proteínas da Membrana Bacteriana Externa/genética , Proteínas da Membrana Bacteriana Externa/metabolismo , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Humanos , Lactente , Proteínas de Membrana Transportadoras/genética , Proteínas de Membrana Transportadoras/metabolismo , Testes de Sensibilidade Microbiana , Óperon , Reação em Cadeia da Polimerase/métodos , Proteínas Repressoras/metabolismo , Transcrição Gênica , beta-Lactamas/farmacologiaRESUMO
In Escherichia coli, beta-lactam resistance usually depends on beta-lactamase production. AmpC chromosomal cephalosporinase hyperproduction is generally due to mutations in the ampC gene promoter. In order to study ampC expression in E. coli clinical strains, we have compared two methods: conventional and real-time reverse transcription-polymerase chain reaction (RT-PCR). With both methods, ampC mRNA was found to be greatly increased in strains presenting -42 or -32 mutations in the ampC promoter, and moderately increased when a -11 mutation was present in the Pribnow box. Real-time RT-PCR represents a powerful tool combining amplification, fluorescent detection and analysis.
Assuntos
Proteínas de Bactérias , Escherichia coli/genética , Escherichia coli/metabolismo , Perfilação da Expressão Gênica/métodos , Resistência beta-Lactâmica , beta-Lactamases/biossíntese , beta-Lactamases/genética , Antibacterianos/farmacologia , Escherichia coli/efeitos dos fármacos , Genes Bacterianos , Testes de Sensibilidade Microbiana , Mutação Puntual , Regiões Promotoras Genéticas , RNA Bacteriano/análise , RNA Mensageiro/análise , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , Transcrição Gênica , beta-Lactamas/farmacologiaAssuntos
Antibacterianos/farmacologia , Proteínas de Bactérias/genética , Ceftazidima/farmacologia , Ciprofloxacina/farmacologia , Farmacorresistência Bacteriana Múltipla/genética , Proteínas de Escherichia coli/genética , Escherichia coli/efeitos dos fármacos , Proteínas Repressoras/genética , beta-Lactamases/genética , Proteínas de Bactérias/metabolismo , Escherichia coli/genética , Infecções por Escherichia coli/tratamento farmacológico , Infecções por Escherichia coli/microbiologia , Proteínas de Escherichia coli/metabolismo , Humanos , Testes de Sensibilidade Microbiana , Dados de Sequência Molecular , Pielonefrite/tratamento farmacológico , Pielonefrite/microbiologia , Proteínas Repressoras/metabolismo , Seleção Genética , Análise de Sequência de DNA , Regulação para Cima , beta-Lactamases/metabolismoRESUMO
An outbreak in a medical intensive care unit was due to an OXA-23-producing Acinetobacter baumannii strain imported from a repatriate hospitalized in Singapore. This outbreak revealed another multidrug resistant epidemic strain that had been present in the hospital for 2 years. Both outbreaks were controlled after 9 months of an extensive infection control program.
Assuntos
Infecções por Acinetobacter/epidemiologia , Infecção Hospitalar/epidemiologia , Surtos de Doenças/prevenção & controle , Surtos de Doenças/estatística & dados numéricos , Farmacorresistência Bacteriana Múltipla , Contaminação de Equipamentos/prevenção & controle , Controle de Infecções/métodos , Infecções por Acinetobacter/prevenção & controle , Idoso , Infecção Hospitalar/prevenção & controle , Feminino , França , Humanos , Unidades de Terapia Intensiva , Masculino , Pessoa de Meia-Idade , SingapuraRESUMO
We investigated the clinical and microbiological epidemiology of AmpC plasmidic cephalosporinases (pAmpC) in Klebsiella pneumoniae strains resistant to ceftazidime, during a 3-year period (2007-2009). Among 1505 K. pneumoniae, 7 were pAmpC producers. Molecular characterization revealed the spread of a ST37 strain producing DHA-1 within intensive care units and the diffusion of the same plasmid among unrelated strains.
Assuntos
Proteínas de Bactérias/genética , Infecções por Klebsiella/epidemiologia , Klebsiella pneumoniae/enzimologia , Klebsiella pneumoniae/genética , Plasmídeos , beta-Lactamases/genética , Adulto , Idoso , Antibacterianos/farmacologia , Ceftazidima/farmacologia , Feminino , Humanos , Klebsiella pneumoniae/efeitos dos fármacos , Klebsiella pneumoniae/isolamento & purificação , Masculino , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , Epidemiologia Molecular , Resistência beta-LactâmicaRESUMO
OBJECTIVES: Little is known about Escherichia coli Orthopaedic Implant Infections (OII) pathogenesis. Thus, we compared 30 clinical strains isolated in this context with 30 clinical strains of faecal origin, in order to identify phenotypic and genetic features related to E. coli OII. METHODS: Phylogenetic analysis and detection of 19 virulence genes were performed by PCR. Ability to form biofilm was studied using the crystal violet reference method and the innovative BioFilm Ring Test(®). RESULTS: Most of the OII isolates (56.7%) belonged to the virulence-associated phylogenetic group B2, but did not present a specific set of virulence factors. S fimbriae was the only adhesin significantly associated with OII isolates. Isolates varied greatly in their ability to form biofilm but OII isolates did not produce significantly more biofilm in vitro than isolates of faecal origin, whatever the method used. CONCLUSIONS: Neither a specific pathogenic signature nor an increased ability to form biofilm in vitro was detected in E. coli strains isolated from OII. Nevertheless, genetic properties of these isolates could provide a clue to their origin. Hence, we found that virulence factors of uropathogenic strains and urological disorders were frequently detected among our OII cohort.