RESUMO

INTRODUCTION: Carbapenem-resistant Pseudomonas aeruginosa (CRPA) is a serious threat to public health. Globally, carbapenemases-producing CRPA isolates mainly belong to 'high-risk' clones; however, the molecular epidemiology of CRPA isolates circulating in Chile are scarce, where this pathogen is the main aetiological agent of ventilator-associated pneumonia. OBJECTIVES: To characterize the phylogenomics and molecular features of ST654 CRPA isolates collected in Chile between 2016 and 2022. METHODS: Eighty-nine CRPA isolates collected in different Chilean hospitals from clinical specimens between 2005 and 2022 were analysed. Antibiotic susceptibility tests and carbapenemases production were carried out on the CRPA ST654 isolates. Also, they were subjected to whole-genome sequencing, from which in silico analyses were performed. RESULTS: Thirty-four strains (38.2%) belonged to the ST654 high-risk clone, being the most predominant lineage of the collection. Most of these isolates belonged to a subclade including KPC producers that also clustered with strains from Argentina and the United States, whereas few VIM and NDM co-producers clustered in two different smaller subclades. The isolates exhibited a broad resistome encompassing genes mediating resistance to several other clinically relevant drugs. Additionally, all the 34 ST654 isolates were ExoS+ as a virulence factor and associated to the O4-serotype. CONCLUSIONS: Our report represents the most comprehensive phylogenomic study of a CRPA high-risk clone ST654 to date. Our analyses suggest that this lineage is undergoing a divergent evolutionary path in Chile, because most of the isolates were KPC producers and were O4 serotype, differing from previous descriptions, which underline the relevance of performing molecular surveillance on this pathogen.

Assuntos

Proteínas de Bactérias , Carbapenêmicos , Testes de Sensibilidade Microbiana , Filogenia , Infecções por Pseudomonas , Pseudomonas aeruginosa , Sequenciamento Completo do Genoma , beta-Lactamases , Pseudomonas aeruginosa/genética , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/isolamento & purificação , Pseudomonas aeruginosa/classificação , Chile/epidemiologia , Humanos , Carbapenêmicos/farmacologia , Infecções por Pseudomonas/microbiologia , Infecções por Pseudomonas/epidemiologia , beta-Lactamases/genética , Proteínas de Bactérias/genética , Hospitais , Antibacterianos/farmacologia , Epidemiologia Molecular , Genoma Bacteriano , Feminino , Masculino , Pessoa de Meia-Idade , Pneumonia Associada à Ventilação Mecânica/microbiologia , Pneumonia Associada à Ventilação Mecânica/epidemiologia , Genômica , Idoso , Adulto , Farmacorresistência Bacteriana Múltipla/genética

RESUMO

The aim of this study was to investigate the genomic features of an extensively drug-resistant (XDR) Pseudomonas aeruginosa isolate (P-469) emerging in Chile. Antibiotic susceptibility was determined by disk diffusion and "colistin agar" test. Whole-genome sequencing (WGS) was performed by the Illumina NextSeq 2000 platform, and epidemiologically and clinically relevant data (i.e., sequence-type, serotype, mobile genetic elements, virulome, resistome, plasmidome, prophages, and CRISPR-Cas systems) were retrieved using multiple bioinformatic tools. The P-469 strain displayed an XDR profile, remaining susceptible to colistin. Genomic analysis revealed that this isolate belonged to the "high-risk" clone ST654 (CC654), serotype O4, and genotype exoS+. Strikingly, two CRISPR-Cas systems, five intact prophages sequences, and a broad resistome that included blaNDM-1 and the novel blaVIM-80 carbapenemase genes were predicted. Our results revealed the genomic characteristics of P. aeruginosa belonging to the high-risk clone ST654/O4 coproducing NDM-1 and VIM-80 in Chile, supporting that genomic surveillance is necessary to track the emergence and spread of epidemiologically successful WHO's critical priority pathogens in order to prevent their rapid dissemination.

Assuntos

Infecções por Pseudomonas , Pseudomonas aeruginosa , Humanos , Pseudomonas aeruginosa/genética , Colistina , Infecções por Pseudomonas/epidemiologia , Testes de Sensibilidade Microbiana , Ágar , Antibacterianos/farmacologia , beta-Lactamases/genética , Células Clonais

RESUMO

Carbapenem-resistant Pseudomonas aeruginosa (CRPA) is one of the pathogens that urgently needs new drugs and new alternatives for its control. The primary strategy to combat this bacterium is combining treatments of beta-lactam with a beta-lactamase inhibitor. The most used combinations against P. aeruginosa are ceftazidime/avibactam (CZA) and ceftolozane/tazobactam (C/T). Although mechanisms leading to CZA and C/T resistance have already been described, among which are the resistance-nodulation-division (RND) efflux pumps, the role that these extrusion systems may play in CZA, and C/T baseline susceptibility of clinical isolates remains unknown. For this purpose, 161 isolates of non-carbapenemase-producing (Non-CP) CRPA were selected, and susceptibility tests to CZA and C/T were performed in the presence and absence of the RND efflux pumps inhibitor, Phenylalanine-arginine ß-naphthylamide (PAßN). In the absence of PAßN, C/T showed markedly higher activity against Non-CP-CRPA isolates than observed for CZA. These results were even more evident in isolates classified as extremely-drug resistant (XDR) or with difficult-to-treat resistance (DTR), where CZA decreased its activity up to 55.2% and 20.0%, respectively, whereas C/T did it up to 82.8% (XDR), and 73.3% (DTR). The presence of PAßN showed an increase in both CZA (37.6%) and C/T (44.6%) activity, and 25.5% of Non-CP-CRPA isolates increased their susceptibility to these two combined antibiotics. However, statistical analysis showed that only the C/T susceptibility of Non-CP-CRPA isolates was significantly increased. Although the contribution of RND activity to CZA and C/T baseline susceptibility was generally low (two-fold decrease of minimal inhibitory concentrations [MIC]), a more evident contribution was observed in a non-minor proportion of the Non-CP-CRPA isolates affected by PAßN [CZA: 25.4% (15/59); C/T: 30% (21/70)]. These isolates presented significantly higher MIC values for C/T. Therefore, we conclude that RND efflux pumps are participating in the phenomenon of baseline susceptibility to CZA and, even more, to C/T. However, the genomic diversity of clinical isolates is so great that deeper analyzes are necessary to determine which elements are directly involved in this phenomenon.

RESUMO

Bloodstream infection (BSI) caused by carbapenem-resistant P. aeruginosa (CRPA) has high mortality in hematopoietic stem cell transplant (HSCT) recipients. We performed MIC, checkerboard, time-kill assay, PFGE, PCR, and whole genome sequence and described the clinical outcome through Epi Info comparing the antimicrobial combination in vitro. Mortality was higher in BSI caused by CRPA carrying the lasB virulence gene. The isolates were 97% resistant to meropenem displaying synergistic effect to 57% in combination with colistin. Seventy-three percent of the isolates harbored blaSPM-1 and Tn4371 and belonged to ST277. The synergistic effect in vitro with meropenem with colistin appeared to be a better therapeutic option.

Assuntos

Antibacterianos/uso terapêutico , Transplante de Células-Tronco Hematopoéticas , Infecções por Pseudomonas/tratamento farmacológico , Sepse/tratamento farmacológico , Adolescente , Adulto , Brasil , Enterobacteriáceas Resistentes a Carbapenêmicos , Carbapenêmicos , Colistina/uso terapêutico , Feminino , Humanos , Masculino , Meropeném/uso terapêutico , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , Infecções por Pseudomonas/microbiologia , Pseudomonas aeruginosa/genética , Pseudomonas aeruginosa/isolamento & purificação , Sepse/mortalidade , Adulto Jovem

RESUMO

BACKGROUND: The assessment of Hospital-acquired infections due to multidrug-resistant bacteria involves the use of a variety of commercial and laboratory-developed tests to detect antimicrobial resistance genes in bacterial pathogens; however, few are evaluated for use in low- and middle-income countries. METHODS: We used whole-genome sequencing, rapid commercial molecular tests, laboratory-developed tests and routine culture testing. RESULTS: We identified the carriage of the metallo-ß-lactamase blaVIM-2 and blaIMP-18 alleles in Carbapenem-Resistant Pseudomonas aeruginosa infections among children in Costa Rica. CONCLUSIONS: The blaIMP-18 allele is not present in the most frequently used commercial tests; thus, it is possible that the circulation of this resistance gene may be underdiagnosed in Costa Rica.

Assuntos

Infecção Hospitalar/microbiologia , Infecções por Pseudomonas/microbiologia , Pseudomonas aeruginosa/genética , Carbapenêmicos , Criança , Costa Rica/epidemiologia , Infecção Hospitalar/epidemiologia , Farmacorresistência Bacteriana Múltipla , Humanos , Testes de Sensibilidade Microbiana , Infecções por Pseudomonas/epidemiologia , Pseudomonas aeruginosa/efeitos dos fármacos , Sequenciamento Completo do Genoma , beta-Lactamases/genética

RESUMO

BACKGROUND: Treatment of serious infections due to multidrug-resistant (MDR) Pseudomonas aeruginosa remains a challenge, despite the introduction of novel therapeutics. In this study, we report 2 extensively drug-resistant clinical isolates of sequence type (ST) 309 P aeruginosa resistant to all ß-lactams, including the novel combinations ceftolozane/tazobactam, ceftazidime/avibactam, and meropenem/vaborbactam. METHODS: Isolates were sequenced using both short-read (Illumina) and long-read technology to identify resistance determinants, polymorphisms (compared with P aeruginosa PAO1), and reconstruct a phylogenetic tree. A pair of ß-lactamases, Guiana extended spectrum ß-lactamase (GES)-19 and GES-26, were cloned and expressed in a laboratory strain of Escherichia coli to examine their relative impact on resistance. Using cell lysates from E coli expressing the GES genes individually and in tandem, we determined relative rates of hydrolysis for nitrocefin and ceftazidime. RESULTS: Two ST309 P aeruginosa clinical isolates were found to harbor the extended spectrum ß-lactamases GES-19 and GES-26 clustered in tandem on a chromosomal class 1 integron. The presence of both enzymes in E coli was associated with significantly elevated minimum inhibitory concentrations to aztreonam, cefepime, meropenem, ceftazidime/avibactam, and ceftolozane/tazobactam, compared with those expressed individually. The combination of ceftazidime/avibactam plus aztreonam was active in vitro and used to achieve cure in one patient. Phylogenetic analysis revealed ST309 P aeruginosa are closely related to MDR strains from Mexico also carrying tandem GES. CONCLUSIONS: The presence of tandem GES-19 and GES-26 is associated with resistance to all ß-lactams, including ceftolozane/tazobactam. Phylogenetic analysis suggests that ST309 P aeruginosa may be an emerging threat in the United States.