RESUMO
Two ceftazidime-avibactam (CAZ-AVI)-resistant Klebsiella pneumoniae carbapenemase (KPC)-positive K. pneumoniae strains, including one pandrug resistant, were isolated in 2019 from two Greek hospitals. The strains were sequence types (ST)s 258 and 147 and both harboured similar self-transmissible IncA/C2 plasmids encoding a novel Lys234Arg variant of the Vietnamese extended-spectrum ß-lactamase (VEB)-1, not inhibited by AVI (VEB-25). Conjugal transfer of VEB-25-encoding plasmids to Escherichia coli yielded CAZ-AVI-resistant clones, supporting that VEB-25 is directly linked to the derived phenotype.
Assuntos
Antibacterianos/farmacologia , Carbapenêmicos/farmacologia , Farmacorresistência Bacteriana Múltipla/genética , Infecções por Klebsiella/microbiologia , Klebsiella pneumoniae/efeitos dos fármacos , Klebsiella pneumoniae/genética , beta-Lactamases/metabolismo , Antibacterianos/uso terapêutico , Compostos Azabicíclicos , Proteínas de Bactérias/genética , Ceftazidima , Combinação de Medicamentos , Farmacorresistência Bacteriana , Genoma Bacteriano , Grécia , Humanos , Infecções por Klebsiella/tratamento farmacológico , Klebsiella pneumoniae/enzimologia , Klebsiella pneumoniae/isolamento & purificação , Testes de Sensibilidade Microbiana , Mutação/genética , Plasmídeos , Sequenciamento Completo do Genoma , beta-Lactamases/genéticaRESUMO
BACKGROUND: Carbapenem-resistant Acinetobacter baumannii (CRAB) has gained global notoriety as a critically important nosocomial pathogen. It mostly affects debilitated patients, causing pneumonia and bloodstream infections with high mortality rates. Difficulties in treating CRAB infections stem from a formidable resistance profile that leaves available only a few antibiotics of uncertain efficacy such as colistin and tigecycline. Despite the relentless attempts to improve therapeutic approaches (as depicted in colistin-oriented randomized clinical trials and the numerous observational studies), progress is still limited. AIMS: We aim (a) to assist physicians to adapt therapeutic approaches in CRAB infections by considering all potentially available antimicrobials, and (b) to present directions for future investigations that emerge through treatment efforts in endemic settings. SOURCES: Articles and reviews from PubMed and Scopus databases; studies from ClinicalTrials.gov; presentations from ECCMID congresses and IDWeek meetings. CONTENT: The review provides a succinct overview of the important pharmacokinetic/pharmocodynamic parameters of relevant antimicrobial agents, a critical appraisal of randomized control trials and observational studies, suggestions for increasing the strength of observational studies and directions facilitating the choice of therapeutic regimens by severity of infection and status of the host. IMPLICATIONS: The lack of an optimal therapeutic regimen for CRAB thus far, as shown in this review, suggests the need to thoroughly investigate alternative approaches through carefully designed trials that should include all relevant drugs. Some of these alternative directions are indicated in the present review.
Assuntos
Infecções por Acinetobacter/tratamento farmacológico , Acinetobacter baumannii/efeitos dos fármacos , Antibacterianos/uso terapêutico , Carbapenêmicos/farmacologia , Farmacorresistência Bacteriana Múltipla , Infecções por Acinetobacter/complicações , Antibacterianos/farmacologia , Infecção Hospitalar/tratamento farmacológico , Infecção Hospitalar/microbiologia , Hospitais , Humanos , Estudos Observacionais como Assunto , Pneumonia Bacteriana/tratamento farmacológico , Ensaios Clínicos Controlados Aleatórios como Assunto , Resultado do TratamentoRESUMO
The cephalosporinase CMY-107, a Tyr199Cys mutant form of CMY-2 encoded by an IncI self-transferable plasmid carried by an Escherichia coli clinical strain, was characterized. The enzyme hydrolyzed oximino-cephalosporins and aztreonam more efficiently than CMY-2 did.
Assuntos
Antibacterianos/química , Cefalosporinas/química , Proteínas de Escherichia coli/química , Escherichia coli/enzimologia , Mutação , Plasmídeos/química , beta-Lactamases/química , Substituição de Aminoácidos , Antibacterianos/metabolismo , Antibacterianos/farmacologia , Cefalosporinas/metabolismo , Cefalosporinas/farmacologia , Cisteína/química , Cisteína/metabolismo , Escherichia coli/genética , Escherichia coli/isolamento & purificação , Infecções por Escherichia coli/microbiologia , Proteínas de Escherichia coli/genética , Proteínas de Escherichia coli/metabolismo , Expressão Gênica , Loci Gênicos , Humanos , Hidrólise , Isoenzimas/química , Isoenzimas/genética , Isoenzimas/metabolismo , Cinética , Testes de Sensibilidade Microbiana , Modelos Moleculares , Tipagem de Sequências Multilocus , Plasmídeos/metabolismo , Estrutura Secundária de Proteína , Estrutura Terciária de Proteína , Especificidade por Substrato , Tirosina/química , Tirosina/metabolismo , beta-Lactamases/genética , beta-Lactamases/metabolismoRESUMO
OBJECTIVES: To characterize the mechanisms implicated in fluoroquinolone (FQ) and expanded-spectrum cephalosporin (ESC) resistance in three clinical and seven faecal multidrug-resistant (MDR; resistant to at least three antimicrobial classes) Escherichia coli isolates from a dog with atopic dermatitis, also suffering from recurrent otitis, that had already been exposed to prolonged antimicrobial treatment and colonized for a long period. METHODS: MICs of FQs, ESCs and other antimicrobials were determined by the broth microdilution method. Phenotypic tests (efflux pump inhibition and combination disc tests) and isoelectric focusing were combined with genotypic analyses [PCRs, sequencing, conjugation, S1 nuclease PFGE, PCR-based replicon typing, plasmid multilocus sequence typing (pMLST) and PCR mapping] to characterize the molecular basis of FQ and ESC resistance. Isolates were further characterized by MLST and PFGE. RESULTS: Three otitis and five faecal isolates with enrofloxacin MICs of 32 to >128 mg/L displayed the GyrA:S83L+D87N/ParC:E62K/ParE:G545D pattern harbouring novel ParC and ParE substitutions, whereas the two remaining faecal isolates were susceptible or borderline resistant single-step mutants (GyrA:S83L pattern) and carried qnrS1. Efflux pump overexpression also contributed to FQ resistance and the MDR phenotype. The three otitis and five faecal isolates also exhibited cefoxitin/ceftazidime MICs of 32-64 mg/L and harboured blaCMY-2, adjusted to ISEcp1, on an IncI1/ST65 conjugative plasmid, previously described in Salmonella Heidelberg from poultry. Interestingly, all isolates shared an identical MLST type (ST212), with the otitis isolates showing indistinguishable patterns with the high-level resistant faecal E. coli isolates. CONCLUSIONS: The long-term maintenance of FQ- and ESC-resistant clones harbouring topoisomerase mutations and a blaCMY-2-IncI1/ST65 plasmid in canine commensal flora after prolonged antimicrobial use may contribute to the dissemination of multidrug resistance.
Assuntos
Proteínas de Bactérias/genética , Farmacorresistência Bacteriana Múltipla/genética , Escherichia coli/efeitos dos fármacos , Escherichia coli/genética , beta-Lactamases/genética , Animais , Antibacterianos/farmacologia , Técnicas de Tipagem Bacteriana , Cefoxitina/farmacologia , Ceftazidima/farmacologia , Cefalosporinas/farmacologia , DNA Girase/genética , DNA Topoisomerase IV/genética , Dermatite Atópica/microbiologia , Cães , Enrofloxacina , Escherichia coli/isolamento & purificação , Infecções por Escherichia coli/tratamento farmacológico , Fezes/microbiologia , Fluoroquinolonas/farmacologia , Testes de Sensibilidade Microbiana , Dados de Sequência Molecular , Tipagem de Sequências Multilocus , Otite/microbiologia , Plasmídeos/genética , Resistência beta-Lactâmica/genéticaRESUMO
This study exploited the possibility to detect Citrobacter freundii-derived CMY-2-like cephalosporinases in Enterobacteriaceae clinical isolates using matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). Periplasmic proteins were prepared using a modified sucrose method and analyzed by MALDI-TOF MS. A ca. 39,850-m/z peak, confirmed to represent a C. freundii-like ß-lactamase by in-gel tryptic digestion followed by MALDI-TOF/TOF MS, was observed only in CMY-producing isolates. We have also shown the potential of the assay to detect ACC- and DHA-like AmpC-type ß-lactamases.
Assuntos
Proteínas de Bactérias/metabolismo , Cefalosporinase/metabolismo , Enterobacteriaceae/enzimologia , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodosRESUMO
The virulence of a KPC-producing Klebsiella pneumoniae sequence type 258 (ST258) strain representing those circulating in Greece was assessed in a mouse septicemia model. The strain was virtually avirulent (50% lethal dose, >10(8) and 5 × 10(7) CFU for immunocompetent and neutropenic animals, respectively). Also, it was highly susceptible to serum killing, rapidly phagocytosed in vitro, and classified as K41, which is not among the virulent capsular types. The findings indirectly support the notion that high ST258-associated mortality is largely due to inefficient antimicrobial treatment.
Assuntos
Klebsiella pneumoniae/efeitos dos fármacos , Klebsiella pneumoniae/enzimologia , beta-Lactamases/metabolismo , Animais , Farmacorresistência Bacteriana Múltipla , Feminino , Humanos , Estimativa de Kaplan-Meier , Camundongos , Camundongos Endogâmicos ICR , Sepse/tratamento farmacológico , Sepse/microbiologiaRESUMO
The nucleotide sequence of pKP1433 (55,417 bp), a blaKPC-2-carrying plasmid from Klebsiella pneumoniae sequence type 340, was determined. pKP1433 displayed extensive sequence and structural similarities with the IncN plasmids possessing the KPC-2-encoding Tn4401b isoform. However, the replication, partitioning, and stability of pKP1433 were determined by sequences related to diverse non-IncN plasmids.
Assuntos
Klebsiella pneumoniae/genética , Plasmídeos/genética , beta-Lactamases/genética , Sequência de Bases , Dados de Sequência Molecular , Análise de Sequência de DNARESUMO
Klebsiella pneumoniae strains co-producing klebsiella pneumoniae carbapenemase (KPC) and verona integron-encoded metallo-beta-lactamase (VIM) are frequently isolated in Greece and have also occurred in other European countries. Conventional combined disc tests exhibit low sensitivity against these emerging pathogens. We have evaluated modifications of the KPC/Metallo-ß-Lactamase Confirmation kit (ROSCO) exhibiting high diagnostic value against KPC, VIM and KPC + VIM producers. The key changes were the inclusion of additional combined tablets containing meropenem plus two inhibitors (dipicolinic acid (1000 µg per tablet) for metallo-ß-lactamases and a boronic acid derivative for KPCs) and the replacement of aminophenylboronic acid by phenylboronic acid (400 µg per tablet).
Assuntos
Antibacterianos/farmacologia , Proteínas de Bactérias/metabolismo , Klebsiella pneumoniae/enzimologia , Klebsiella pneumoniae/isolamento & purificação , Testes de Sensibilidade Microbiana/métodos , beta-Lactamases/metabolismo , Proteínas de Bactérias/isolamento & purificação , Cloxacilina/farmacologia , Europa (Continente) , Grécia , Imipenem/farmacologia , Infecções por Klebsiella/microbiologia , Klebsiella pneumoniae/efeitos dos fármacos , Klebsiella pneumoniae/metabolismo , Meropeném , Ácidos Picolínicos/farmacologia , Reprodutibilidade dos Testes , Tienamicinas/farmacologia , beta-Lactamases/isolamento & purificaçãoRESUMO
OBJECTIVES: To determine the complete nucleotide sequence of the VIM-1-encoding plasmid pKP1780 from Klebsiella pneumoniae ST147 representing a distinct group of IncR replicons. METHODS: The plasmid pKP1780 was from a K. pneumoniae clinical strain (KP-1780) isolated in Greece in 2009. Plasmid DNA was extracted from an Escherichia coli DH5α transformant and sequenced using the 454 Genome Sequencer GS FLX procedure on a standard fragment DNA library. Contig gaps were filled by sequencing of PCR-produced fragments. Annotation and comparative analysis were performed using software available on the Internet. RESULTS: Plasmid pKP1780 (49â770 bp) consisted of an IncR-related sequence (12 083 bp) including replication and stability systems, and a multidrug resistance (MDR) mosaic region (37â687 bp). blaVIM-1 along with the aacA7, dfrA1 and aadA1 cassettes comprised the variable region of an integron similar to In-e541 from pNL194. The mosaic structure also included the strA, strB, aphA1 and mphA resistance genes as well as intact (n = 10) or defective (n = 3) insertion sequences and fragments of various transposons. CONCLUSIONS: The mosaic structure of pKP1780 exhibited high similarity with the acquired region of the IncN plasmid pNL194, indicating the acquisition of the VIM-1-encoding MDR region from pNL194 by an IncR-type plasmid.
Assuntos
Klebsiella pneumoniae/enzimologia , Klebsiella pneumoniae/genética , Plasmídeos/isolamento & purificação , DNA Bacteriano/química , DNA Bacteriano/genética , Ordem dos Genes , Grécia , Humanos , Infecções por Klebsiella/microbiologia , Klebsiella pneumoniae/isolamento & purificação , Dados de Sequência Molecular , Análise de Sequência de DNA , beta-Lactamases/genéticaRESUMO
Plasmid-acquired carbapenemases in Enterobacteriaceae, which were first discovered in Europe in the 1990s, are now increasingly being identified at an alarming rate. Although their hydrolysis spectrum may vary, they hydrolyse most ß-lactams, including carbapenems. They are mostly of the KPC, VIM, NDM and OXA-48 types. Their prevalence in Europe as reported in 2011 varies significantly from high (Greece and Italy) to low (Nordic countries). The types of carbapenemase vary among countries, partially depending on the cultural/population exchange relationship between the European countries and the possible reservoirs of each carbapenemase. Carbapenemase producers are mainly identified among Klebsiella pneumoniae and Escherichia coli, and still mostly in hospital settings and rarely in the community. Although important nosocomial outbreaks with carbapenemase-producing Enterobacteriaceae have been extensively reported, many new cases are still related to importation from a foreign country. Rapid identification of colonized or infected patients and screening of carriers is possible, and will probably be effective for prevention of a scenario of endemicity, as now reported for extended-spectrum ß-lactamase (mainly CTX-M) producers in all European countries.
Assuntos
Proteínas de Bactérias/genética , Infecção Hospitalar/transmissão , Infecções por Enterobacteriaceae/transmissão , Enterobacteriaceae/enzimologia , Evolução Molecular , beta-Lactamases/genética , Antibacterianos/farmacologia , Proteínas de Bactérias/biossíntese , Carbapenêmicos/farmacologia , Infecção Hospitalar/epidemiologia , Infecção Hospitalar/microbiologia , Farmacorresistência Bacteriana , Enterobacteriaceae/efeitos dos fármacos , Enterobacteriaceae/genética , Infecções por Enterobacteriaceae/epidemiologia , Infecções por Enterobacteriaceae/microbiologia , Europa (Continente)/epidemiologia , Feminino , Humanos , Masculino , Prevalência , Fatores de Tempo , beta-Lactamases/biossínteseRESUMO
Carbapenem-hydrolysing ß-lactamases are the most powerful ß-lactamases, being able to hydrolyse almost all ß-lactams. They are mostly of the KPC, VIM, IMP, NDM and OXA-48 types. Their current extensive spread worldwide in Enterobacteriaceae is an important source of concern, as these carbapenemase producers are multidrug-resistant. Detection of infected patients and of carriers are the two main approaches for prevention of their spread. Phenotypic and molecular-based techniques are able to identify these carbapenemase producers, although with variable efficiencies. The detection of carriers still relies mostly on the use of screening culture media.
Assuntos
Proteínas de Bactérias/biossíntese , Portador Sadio/microbiologia , Infecções por Enterobacteriaceae/microbiologia , Enterobacteriaceae/classificação , Enterobacteriaceae/isolamento & purificação , Programas de Rastreamento/métodos , Resistência beta-Lactâmica , beta-Lactamases/biossíntese , Proteínas de Bactérias/genética , Portador Sadio/diagnóstico , Portador Sadio/epidemiologia , Meios de Cultura , Enterobacteriaceae/enzimologia , Enterobacteriaceae/genética , Infecções por Enterobacteriaceae/diagnóstico , Infecções por Enterobacteriaceae/epidemiologia , Humanos , Testes de Sensibilidade Microbiana , beta-Lactamases/genética , beta-Lactamas/farmacologiaRESUMO
We report on the sequence type and beta-lactamase content of 174 carbapenem-resistant Acinetobacter baumannii isolates recovered from clinical specimens during 2010 and 2011 in a tertiary care hospital in central Greece. Carbapenem resistance was associated mainly with carriage of the bla(OXA-23) gene (in 72.4% of the isolates). To our knowledge, this is the first description of A. baumannii strains producing OXA-23 in Greece. During 2011, in our hospital they rapidly 'replaced' the previously predominant OXA-58- positive A. baumannii strains.
Assuntos
Infecções por Acinetobacter/epidemiologia , Infecções por Acinetobacter/microbiologia , Acinetobacter/enzimologia , Acinetobacter/isolamento & purificação , Infecção Hospitalar/epidemiologia , Infecção Hospitalar/microbiologia , beta-Lactamases/metabolismo , Acinetobacter/classificação , Adolescente , Adulto , Idoso , Feminino , Grécia/epidemiologia , Humanos , Masculino , Pessoa de Meia-Idade , Prevalência , Especificidade da Espécie , Adulto JovemRESUMO
This report describes the detection of Citrobacter koseri carrying K. pneumoniae carbapenemase (KPC-2) isolated in July 2011 from a Greek patient, who was also colonised by a Klebsiella pneumoniae strain coproducing KPC-2 and Verona integron-encoded metallo-beta-lactamase (VIM)-1.
Assuntos
Proteínas de Bactérias/metabolismo , Citrobacter koseri/isolamento & purificação , Infecções por Enterobacteriaceae/microbiologia , beta-Lactamases/metabolismo , Idoso de 80 Anos ou mais , Ciprofloxacina/uso terapêutico , Citrobacter koseri/efeitos dos fármacos , Citrobacter koseri/enzimologia , Citrobacter koseri/patogenicidade , Farmacorresistência Bacteriana Múltipla , Infecções por Enterobacteriaceae/tratamento farmacológico , Fezes/microbiologia , Grécia , Humanos , Klebsiella pneumoniae/efeitos dos fármacos , Klebsiella pneumoniae/enzimologia , Klebsiella pneumoniae/isolamento & purificação , Klebsiella pneumoniae/patogenicidade , Masculino , Testes de Sensibilidade MicrobianaAssuntos
Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Antituberculosos/farmacologia , Proteínas de Bactérias/biossíntese , Carbapenêmicos/uso terapêutico , Farmacorresistência Bacteriana , Infecções por Klebsiella/tratamento farmacológico , Klebsiella pneumoniae/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Mycobacterium tuberculosis/efeitos dos fármacos , Infecções Estafilocócicas/tratamento farmacológico , Staphylococcus aureus/efeitos dos fármacos , beta-Lactamases/biossíntese , Animais , HumanosRESUMO
VIM-27 metallo-ß-lactamase, an Ala(57) â Ser variant of VIM-1, was identified in three Klebsiella pneumoniae isolates belonging to sequence type 147. bla(VIM-27) was part of a class 1 integron carried by non-self-transferable plasmids. Kinetic parameters and MIC determinations indicated that VIM-27 hydrolyzed most ß-lactams, especially imipenem and cefoxitin, less effectively than VIM-1.
Assuntos
Klebsiella pneumoniae/enzimologia , beta-Lactamases/química , beta-Lactamases/metabolismo , Antibacterianos/farmacologia , Cefoxitina/farmacologia , Farmacorresistência Bacteriana Múltipla/genética , Imipenem/farmacologia , Klebsiella pneumoniae/efeitos dos fármacos , Klebsiella pneumoniae/genética , Testes de Sensibilidade Microbiana , Dados de Sequência Molecular , Estrutura Molecular , beta-Lactamases/genéticaRESUMO
Proteus mirabilis isolates obtained in 1999 to 2008 from three European countries were analyzed; all carried chromosomal AmpC-type cephalosporinase bla(CMY) genes from a Citrobacter freundii origin (bla(CMY-2)-like genes). Isolates from Poland harbored several bla(CMY) genes (bla(CMY-4), bla(CMY-12), bla(CMY-14), bla(CMY-15), and bla(CMY-38) and the new gene bla(CMY-45)), while isolates from Italy and Greece harbored bla(CMY-16) only. Earlier isolates with bla(CMY-4) or bla(CMY-12), recovered in France from Greek and Algerian patients, were also studied. All isolates showed striking similarities. Their bla(CMY) genes resided within ISEcp1 transposition modules, named Tn6093, characterized by a 110-bp distance between ISEcp1 and bla(CMY), and identical fragments of both C. freundii DNA and a ColE1-type plasmid backbone. Moreover, these modules were inserted into the same chromosomal site, within the pepQ gene. Since ColE1 plasmids carrying ISEcp1 with similar C. freundii DNA fragments (Tn6114) had been identified earlier, it is likely that a similar molecule had mediated at some stage this DNA transfer between C. freundii and P. mirabilis. In addition, isolates with bla(CMY-12), bla(CMY-15), and bla(CMY-38) genes harbored a second bla(CMY) copy within a shorter ISEcp1 module (Tn6113), always inserted downstream of the ppiD gene. Sequence analysis of all mobile bla(CMY-2)-like genes indicated that those integrated in the P. mirabilis chromosome form a distinct cluster that may have evolved by the stepwise accumulation of mutations. All of these observations, coupled to strain typing data, suggest that the bla(CMY) genes studied here may have originated from a single ISEcp1-mediated mobilization-transfer-integration process, followed by the spread and evolution of a P. mirabilis clone over time and a large geographic area.
Assuntos
Proteínas de Bactérias/genética , Farmacorresistência Bacteriana Múltipla , Evolução Molecular , Proteus mirabilis/efeitos dos fármacos , Proteus mirabilis/genética , beta-Lactamases/genética , Cromossomos Bacterianos , Humanos , Testes de Sensibilidade Microbiana , Proteus mirabilis/enzimologiaRESUMO
The sequence of pR3521, a self-transmissible plasmid from Escherichia coli, was determined. pR3521 (110,416 bp) comprised a contiguous IncB sequence (84,034 bp) sharing extensive similarities with IncI replicons and an acquired region (26,382 bp) carrying sequences of diverse origin, containing bla(ACC-4), bla(SCO-1), bla(TEM-1b) (two copies), strA, strB, sul2, and aacC2.