RESUMO
The use of ß-lactam/ß-lactamase inhibitors constitutes an important strategy to counteract ß-lactamases in multidrug-resistant (MDR) Gram-negative bacteria. Recent reports have described ceftazidime-/avibactam-resistant isolates producing CTX-M variants with different amino acid substitutions (e.g., P167S, L169Q, and S130G). Relebactam (REL) combined with imipenem has proved very effective against Enterobacterales producing ESBLs, serine-carbapenemases, and AmpCs. Herein, we evaluated the inhibitory efficacy of REL against CTX-M-96, a CTX-M-15-type variant. The CTX-M-96 structure was obtained in complex with REL at 1.03 Å resolution (PDB 8EHH). REL was covalently bound to the S70-Oγ atom upon cleavage of the C7-N6 bond. Compared with apo CTX-M-96, binding of REL forces a slight displacement of the deacylating water inwards the active site (0.81 Å), making the E166 and N170 side chains shift to create a proper hydrogen bonding network. Binding of REL also disturbs the hydrophobic patch formed by Y105, P107, and Y129, likely due to the piperidine ring of REL that creates clashes with these residues. Also, a remarkable change in the positioning of the N104 sidechain is also affected by the piperidine ring. Therefore, differences in the kinetic behavior of REL against class A ß-lactamases seem to rely, at least in part, on differences in the residues being involved in the association and stabilization of the inhibitor before hydrolysis. Our data provide the biochemical and structural basis for REL effectiveness against CTX-M-producing Gram-negative pathogens and essential details for further DBO design. Imipenem/REL remains an important choice for dealing with isolates co-producing CTX-M with other ß-lactamases.
Assuntos
Compostos Azabicíclicos , Inibidores de beta-Lactamases , beta-Lactamases , Compostos Azabicíclicos/farmacologia , Compostos Azabicíclicos/química , beta-Lactamases/genética , beta-Lactamases/metabolismo , beta-Lactamases/química , Inibidores de beta-Lactamases/farmacologia , Inibidores de beta-Lactamases/química , Cristalografia por Raios X , Antibacterianos/farmacologia , Imipenem/farmacologia , Imipenem/química , Ceftazidima/farmacologia , Testes de Sensibilidade Microbiana , Domínio CatalíticoRESUMO
OBJECTIVE: Ceftazidime-avibactam (CZA) is a good option for Gram-negative bacilli infections that produce carbapenemase Classes A (especially blaKPC) and D (blaOXA). However, it is unknown whether it would have an impact on metallo-ß-lactamases (blaMBL) selection. The aim of the study was to compare carbapenem and CZA Klebsiella pneumoniae (KPN) susceptibility profiles for a period of two years following the introduction of CZA. METHODS: The study was conducted in a 36-bed adult ICU of a tertiary hospital in Buenos Aires, Argentina. Antimicrobial consumption was expressed as days of treatment per 100 patients-day (DOT). RESULTS: A total of 123 KPN strains in the first year and 172 in the second year were analyzed. An alarming decrease in carbapenem susceptibility was detected in the second year (OR 0.5 [0.3-0.8] p<.001). In parallel, there was a decrease in CZA susceptibility (OR 0.5 [0.3-0.9] p<.05). These findings were linked to a rise in blaMBL-KPN (32.1% vs. 45.1%, OR 1.7 [1.1-2.9], p <.04) during the second year. This new KPN susceptibility profile promoted an increment in CZA (1.0 DOT vs. 6.6 DOT, OR 6.6 [4.9-9.1] p<.001) and aztreonam (0.3 DOT vs. 4.1 DOT, OR 16.3 [9.1-29.3] p<.001) consumption. Thus, there was a decrease in carbapenem prescription (17.8 DOT vs. 15.4 DOT, OR 0.8 [0.8-0.9] p<.001). CONCLUSIONS: There was an escalation of blaMBL-KPN rate two years after CZA introduction, leading to a decrease in CZA and carbapenem susceptibility and an increase in CZA and aztreonam prescriptions.
Assuntos
Antibacterianos , Compostos Azabicíclicos , Ceftazidima , Combinação de Medicamentos , Unidades de Terapia Intensiva , Infecções por Klebsiella , Klebsiella pneumoniae , Testes de Sensibilidade Microbiana , beta-Lactamases , Ceftazidima/farmacologia , Ceftazidima/uso terapêutico , Compostos Azabicíclicos/uso terapêutico , Compostos Azabicíclicos/farmacologia , Klebsiella pneumoniae/efeitos dos fármacos , Klebsiella pneumoniae/genética , Argentina , Humanos , Antibacterianos/uso terapêutico , Antibacterianos/farmacologia , beta-Lactamases/genética , Infecções por Klebsiella/tratamento farmacológico , Infecções por Klebsiella/microbiologia , Carbapenêmicos/farmacologia , Carbapenêmicos/uso terapêutico , Centros de Atenção TerciáriaRESUMO
INTRODUCTION: Novel beta-lactam/beta-lactamase inhibitor (BIBLI) combinations are commercially available and have been used for treating carbapenem-resistant Klebsiella pneumoniae (CRKP) infections. Continuous surveillance of susceptibility profiles and resistance mechanism identification are necessary to monitor the evolution of resistance within these agents. OBJECTIVE: The purpose of this study was to evaluate the susceptibility rates of ceftazidime/avibactam, imipenem/relebactam and meropenem/vaborbactam in CRKP isolated from patients with bloodstream infections who underwent screening for a randomized clinical trial in Brazil. METHODS: Minimum inhibitory concentrations (MICs) were determined for meropenem, ceftazidime/avibactam, imipenem/relebactam and meropenem/vaborbactam using the gradient diffusion strip method. Carbapenemase genes were detected by multiplex real-time polymerase chain reaction. Klebsiella pneumoniae carbapenemase (KPC)-producing isolates showing resistance to any BLBLI and New Delhi Metallo-beta-lactamase (NDM)-producing isolates with susceptibility to any BLBLI isolates were further submitted for whole-genome sequencing. RESULTS: From a total of 69 CRKP isolates, 39 were positive for blaKPC, 19 for blaNDM and 11 for blaKPC and blaNDM. KPC-producing isolates demonstrated susceptibility rates above 94â¯% for all BLBLIs. Two isolates with resistance to meropenem/vaborbactam demonstrated a Gly and Asp duplication at the porin OmpK36 as well as a truncated OmpK35. All NDM-producing isolates, including KPC and NDM coproducers, demonstrated susceptibility rates to ceftazidime/avibactam, imipenem/relebactam and meropenem/vaborbactam of 0â¯%, 9.1-21.1â¯% and 9.1-26.3â¯%, respectively. Five NDM-producing isolates that presented susceptibility to BLBLIs also had porin alterations CONCLUSIONS: This study showed that, although high susceptibility rates to BLBLIs were found, KPC-2 isolates were able to demonstrate resistance probably as a result of porin mutations. Additionally, NDM-1 isolates showed susceptibility to BLBLIs in vitro.
Assuntos
Antibacterianos , Compostos Azabicíclicos , Enterobacteriáceas Resistentes a Carbapenêmicos , Ceftazidima , Combinação de Medicamentos , Infecções por Klebsiella , Klebsiella pneumoniae , Testes de Sensibilidade Microbiana , Inibidores de beta-Lactamases , beta-Lactamases , Humanos , Brasil , Klebsiella pneumoniae/efeitos dos fármacos , Klebsiella pneumoniae/genética , Klebsiella pneumoniae/isolamento & purificação , Inibidores de beta-Lactamases/farmacologia , Infecções por Klebsiella/microbiologia , Compostos Azabicíclicos/farmacologia , Ceftazidima/farmacologia , beta-Lactamases/genética , Antibacterianos/farmacologia , Enterobacteriáceas Resistentes a Carbapenêmicos/efeitos dos fármacos , Enterobacteriáceas Resistentes a Carbapenêmicos/genética , Enterobacteriáceas Resistentes a Carbapenêmicos/isolamento & purificação , Proteínas de Bactérias/genética , Meropeném/farmacologia , Imipenem/farmacologia , Bacteriemia/microbiologia , Ácidos Borônicos/farmacologia , Compostos Heterocíclicos com 1 AnelRESUMO
Introduction: Ceftazidime/avibactam (CZA) is indicated against multidrug-resistant Pseudomonas aeruginosa, particularly those that are carbapenem resistant. CZA resistance in P. aeruginosa producing PER, a class A extended-spectrum ß-lactamase, has been well documented in vitro. However, data regarding clinical isolates are scarce. Our aim was to analyze the contribution of PER to CZA resistance in non-carbapenemase-producing P. aeruginosa clinical isolates that were ceftazidime and/or carbapenem non-susceptible. Methods: Antimicrobial susceptibility was determined through agar dilution and broth microdilution, while bla PER gene was screened through PCR. All PER-positive isolates and five PER-negative isolates were analyzed through Whole Genome Sequencing. The mutational resistome associated to CZA resistance was determined through sequence analysis of genes coding for PBPs 1b, 3 and 4, MexAB-OprM regulators MexZ, MexR, NalC and NalD, AmpC regulators AmpD and AmpR, and OprD porin. Loss of bla PER-3 gene was induced in a PER-positive isolate by successive passages at 43°C without antibiotics. Results: Twenty-six of 287 isolates studied (9.1%) were CZA-resistant. Thirteen of 26 CZA-resistant isolates (50%) carried bla PER. One isolate carried bla PER but was CZA-susceptible. PER-producing isolates had significantly higher MICs for CZA, amikacin, gentamicin, ceftazidime, meropenem and ciprofloxacin than non-PER-producing isolates. All PER-producing isolates were ST309 and their bla PER-3 gene was associated to ISCR1, an insertion sequence known to mobilize adjacent DNA. PER-negative isolates were classified as ST41, ST235 (two isolates), ST395 and ST253. PER-negative isolates carried genes for narrow-spectrum ß-lactamases and the mutational resistome showed that all isolates had one major alteration in at least one of the genes analyzed. Loss of bla PER-3 gene restored susceptibility to CZA, ceftolozane/tazobactam and other ß-lactamsin the in vitro evolved isolate. Discussion: PER-3-producing ST309 P. aeruginosa is a successful multidrug-resistant clone with blaPER-3 gene implicated in resistance to CZA and other ß-lactams.
Assuntos
Antibacterianos , Compostos Azabicíclicos , Proteínas de Bactérias , Ceftazidima , Combinação de Medicamentos , Farmacorresistência Bacteriana Múltipla , Testes de Sensibilidade Microbiana , Infecções por Pseudomonas , Pseudomonas aeruginosa , beta-Lactamases , Ceftazidima/farmacologia , Pseudomonas aeruginosa/genética , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/metabolismo , Pseudomonas aeruginosa/isolamento & purificação , Compostos Azabicíclicos/farmacologia , Humanos , beta-Lactamases/genética , beta-Lactamases/metabolismo , Antibacterianos/farmacologia , Infecções por Pseudomonas/microbiologia , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Farmacorresistência Bacteriana Múltipla/genética , Chile , Sequenciamento Completo do Genoma , MutaçãoRESUMO
Resistance to ceftazidime-avibactam (CZA) due to Klebsiella pneumoniae carbapenemase (KPC) variants is increasing worldwide. We characterized two CZA-resistant clinical Klebsiella pneumoniae strains by antimicrobial susceptibility test, conjugation assays, and WGS. Isolates belonged to ST258 and ST45, and produced a KPC-31 and a novel variant KPC-197, respectively. The novel KPC variant presents a deletion of two amino acids on the Ω-loop (del_168-169_EL) and an insertion of two amino acids in position 274 (Ins_274_DS). Continued surveillance of KPC variants conferring CZA resistance in Colombia is warranted. IMPORTANCE: Latin America and the Caribbean is an endemic region for carbapenemases. Increasingly high rates of Klebsiella pneumoniae carbapenemase (KPC) have established ceftazidime-avibactam (CZA) as an essential antimicrobial for the treatment of infections due to MDR Gram-negative pathogens. Although other countries in the region have reported the emergence of CZA-resistant KPC variants, this is the first description of such enzymes in Colombia. This finding warrants active surveillance, as dissemination of these variants could have devastating public health consequences.
Assuntos
Antibacterianos , Compostos Azabicíclicos , Proteínas de Bactérias , Ceftazidima , Combinação de Medicamentos , Farmacorresistência Bacteriana Múltipla , Infecções por Klebsiella , Klebsiella pneumoniae , Testes de Sensibilidade Microbiana , beta-Lactamases , Compostos Azabicíclicos/farmacologia , Ceftazidima/farmacologia , Klebsiella pneumoniae/genética , Klebsiella pneumoniae/efeitos dos fármacos , Klebsiella pneumoniae/enzimologia , Colômbia , beta-Lactamases/genética , beta-Lactamases/metabolismo , Humanos , Antibacterianos/farmacologia , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Farmacorresistência Bacteriana Múltipla/genética , Infecções por Klebsiella/microbiologia , Infecções por Klebsiella/tratamento farmacológicoRESUMO
BACKGROUND: Infections caused by Stenotrophomonas maltophilia and related species are increasing worldwide. Unfortunately, treatment options are limited, whereas the antimicrobial resistance is increasing. METHODS: We included clinical isolates identified as S. maltophilia by VITEK 2 Compact. Ceftazidime/avibactam, meropenem/vaborbactam, imipenem/relebactam, cefiderocol, quinolones, and tetracycline family members were evaluated by broth microdilution method and compared with first-line treatment drugs. Minimum inhibitory concentrations (MICs) were reported for all antibiotics. We sequenced the Whole Genome of cefiderocol resistant strains (CRSs) and annotated their genes associated with cefiderocol resistance (GACR). Presumptive phylogenetic identification employing the 16S marker was performed. RESULTS: One hundred and one clinical strains were evaluated, sulfamethoxazole and trimethoprim, levofloxacin and minocycline showed susceptibilities of 99.01%, 95.04% and 100% respectively. Ceftazidime was the antibiotic with the highest percentage of resistance in all samples (77.22%). Five strains were resistant to cefiderocol exhibiting MIC values ≥ 2 µg/mL (4.95%). The ß-lactamase inhibitors meropenem/vaborbactam and imipenem/relebactam, failed to inhibit S. maltophilia, preserving both MIC50 and MIC90 ≥64 µg/mL. Ceftazidime/avibactam restored the activity of ceftazidime decreasing the MIC range. Tigecycline had the lowest MIC range, MIC50 and MIC90. Phylogeny based on 16S rRNA allowed to identify to cefiderocol resistant strains as putative species clustered into Stenotrophomonas maltophilia complex (Smc). In these strains, we detected GARCs such as Mutiple Drug Resistance (MDR) efflux pumps, L1-type ß-lactamases, iron transporters and type-1 fimbriae. CONCLUSION: Antimicrobial resistance to first-line treatment is low. The in vitro activity of new ß-lactamase inhibitors against S. maltophilia is poor, but avibactam may be a potential option. Cefiderocol could be considered as a potential new option for multidrug resistant infections. Tetracyclines had the best in vitro activity of all antibiotics evaluated.
Assuntos
Ácidos Borônicos , Ceftazidima , Stenotrophomonas maltophilia , Ceftazidima/farmacologia , Cefiderocol , Meropeném , Inibidores de beta-Lactamases/farmacologia , Inibidores de beta-Lactamases/uso terapêutico , Stenotrophomonas , Filogenia , RNA Ribossômico 16S , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Compostos Azabicíclicos/farmacologia , Combinação de Medicamentos , Imipenem/farmacologia , Testes de Sensibilidade Microbiana , beta-Lactamases/genéticaAssuntos
Antibacterianos , Compostos Azabicíclicos , Ceftazidima , Combinação de Medicamentos , beta-Lactamases , Compostos Azabicíclicos/farmacologia , Ceftazidima/farmacologia , beta-Lactamases/genética , Humanos , Antibacterianos/farmacologia , Testes de Sensibilidade Microbiana , Cromatografia de Afinidade/métodos , Proteínas de Bactérias/genéticaRESUMO
OBJECTIVES: To describe at genomic level nine carbapenemase-producing Klebsiella pneumoniae ST307 (Kp-ST307) clinical isolates recovered in Buenos Aires during 2017 to 2021, investigating their resistome, virulome, and phylogeny. METHODS: Antimicrobial susceptibility was determined according to Clinical and Laboratory Standards Intitute (CLSI). Genomic DNA was sequenced by Illumina MiSeq and analysed using SPAdes, PROKKA, and Kleborate. Phylogeny of 355 randomly selected Kp-ST307 genomes and those from nine local isolates was inferred by a maximum-likelihood approach. The tree was visualized using Microreact. RESULTS: Besides resistance to ß-lactams and fluoroquinolones, six out of nine Kp-ST307 were also resistant to ceftazidime/avibactam (CZA). This difficult-to-treat resvistance phenotype was mediated by blaSHV-28 and GyrA-83I/ParC-80I mutations in addition to carbapenemase coding genes. Among CZA susceptible isolates, two of them harboured blaKPC-3 while the other harboured blaKPC-2+blaCTX-M-15. Regarding CZA-resistant isolates, three harboured blaKPC-3+blaNDM-1+blaCMY-6, two carried blaKPC-2+blaNDM-5+blaCTX-M-15, and blaNDM-5+blaCTX-M-15 were detected in the remaining isolate. Furthermore, five colistin-resistant isolates presented a nonsense mutation in mgrB. Global Kp-ST307 isolates were distributed in two deep-branching lineages while local isolates were set in the main clade of the phylogenetic tree. The five isolates from the same hospital, harbouring blaKPC-3 or blaKPC-3+blaNDM-1+blaCMY-6, clustered in a monophyletic subclade with Italian isolates. Also, an isolate harbouring blaKPC-2+blaNDM-5+blaCTX-M-15 recovered in another hospital was closed to this group. The remaining local Kp-ST307 were grouped in other subclades containing isolates of diverse geographical origin. CONCLUSION: The inferred resistome was consistent with the resistant phenotype. Phylogeny suggested multiple introduction events in our region and a single major introduction in one hospital followed by local spread.
Assuntos
Antibacterianos , Proteínas de Bactérias , Ceftazidima , Infecções por Klebsiella , Klebsiella pneumoniae , Testes de Sensibilidade Microbiana , Filogenia , beta-Lactamases , Klebsiella pneumoniae/genética , Klebsiella pneumoniae/efeitos dos fármacos , Klebsiella pneumoniae/isolamento & purificação , Klebsiella pneumoniae/enzimologia , Klebsiella pneumoniae/classificação , Argentina , beta-Lactamases/genética , Proteínas de Bactérias/genética , Humanos , Infecções por Klebsiella/microbiologia , Antibacterianos/farmacologia , Ceftazidima/farmacologia , Farmacorresistência Bacteriana Múltipla/genética , Genoma Bacteriano , Compostos Azabicíclicos/farmacologia , Combinação de Medicamentos , Genômica , Sequenciamento Completo do GenomaRESUMO
We assessed 160 patients who received imipenem/cilastatin/relebactam for ≥2 days. At treatment initiation, the median Charlson Comorbidity Index was 5, 45% were in the intensive care unit, and 19% required vasopressor support. The in-hospital mortality rate was 24%. These data advance our understanding of real-world indications and outcomes of imipenem/cilastatin/relebactam use.
Assuntos
Antibacterianos , Compostos Azabicíclicos , Cilastatina , Imipenem , Humanos , Masculino , Antibacterianos/farmacologia , Feminino , Imipenem/farmacologia , Pessoa de Meia-Idade , Idoso , Cilastatina/farmacologia , Cilastatina/administração & dosagem , Cilastatina/uso terapêutico , Estados Unidos , Compostos Azabicíclicos/farmacologia , Combinação Imipenem e Cilastatina/administração & dosagem , Mortalidade Hospitalar , Estudos Retrospectivos , Unidades de Terapia Intensiva , Idoso de 80 Anos ou mais , Resultado do Tratamento , AdultoRESUMO
OBJECTIVES: Ceftazidime-avibactam (CAZ-AVI) is an option for infections caused by MDR gram-negative bacilli. In this study, we aimed to analyze the in vitro antimicrobial activity of CAZ-AVI and other antimicrobial agents against gram-negative bacilli that were collected in Colombia between 2019 and 2021 from patients with bacteremia and skin and soft-tissue infections (SSTIs). METHODS: A total of 600 Enterobacterales and 259 P. aeruginosa strains were analyzed. The phenotypic resistance of isolates, particularly non-susceptibility to meropenem, multidrug-resistant (MDR) isolates, and difficult-to-treat (DTR) P. aeruginosa, was evaluated according to CLSI breakpoints. RESULTS: Enterobacterales had the most susceptibility to CAZ-AVI (96.5 %) and tigecycline (95 %). Tigecycline and CAZ-AVI were the antimicrobial agents with the most in vitro activity against carbapenem-resistant Enterobacterales (CRE). CAZ-AVI was the antimicrobial treatment with the most activity against P. aeruginosa. CONCLUSIONS: Tigecycline and CAZ-AVI were the antimicrobial agents with the most activity against CRE and MDR Enterobacterales. For P. aeruginosa, CAZ-AVI was the antimicrobial treatment with the most in vitro activity.