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1.
J Appl Microbiol ; 135(6)2024 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-38849309

RESUMO

AIMS: To investigate alternative resistance mechanisms among seven ceftazidime-avibactam (CZA)-resistant carbapenem-resistant Klebsiella pneumoniae (CRKP) strains lacking common antimicrobial resistance genes (ARGs) using whole genome sequencing. METHODS AND RESULTS: ARG and virulence factors (VFs) were screened using the ARG database CARD and the VF database, respectively, and identified using genomic annotation data with BLAST+. Six strains were ST11 sequence types (STs), and one was ST2123. ST11 strains harbored more ARGs than the ST2123 strains. All seven strains carried multiple ARGs with efflux-mediated antibiotic resistance, including oqxA, oqxB, tet (A), qacEdltal, CRP, H-NS, Kpn-E, F, G, H, acrA, LptD, acrB, acrD, cpxA, mdtB, and mdtC. These efflux-mediated ARGs were identified in most strains and even all strains. Whole genome sequencing revealed that the ST11 strain carried multiple potential prophages, genomic islands, and integrative and conjugative elements, while the ST2123 strain carried an independent potential prophages and a genomic island. CONCLUSIONS: Whole genome sequencing analysis revealed that these seven CZA-resistant CRKP strains lacking common ARGs exhibited efflux-mediated antibiotic resistance-associated ARGs. The main mechanism by which CRKP resists CZA is antibiotic inactivation. Except for tet (A), no ARGs and validation experiments related to efflux were found. This study's results provide a new possibility for the resistance mechanism of CRKP to CZA, and we will verify this conclusion through experiments in the future.


Assuntos
Antibacterianos , Compostos Azabicíclicos , Ceftazidima , Combinação de Medicamentos , Klebsiella pneumoniae , Testes de Sensibilidade Microbiana , Sequenciamento Completo do Genoma , Ceftazidima/farmacologia , Klebsiella pneumoniae/genética , Klebsiella pneumoniae/efeitos dos fármacos , Compostos Azabicíclicos/farmacologia , Antibacterianos/farmacologia , Genoma Bacteriano , Farmacorresistência Bacteriana Múltipla/genética , Humanos , Enterobacteriáceas Resistentes a Carbapenêmicos/genética , Enterobacteriáceas Resistentes a Carbapenêmicos/efeitos dos fármacos , Infecções por Klebsiella/microbiologia , Carbapenêmicos/farmacologia , Fatores de Virulência/genética
2.
BMJ Case Rep ; 17(6)2024 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-38885998

RESUMO

A man in his 40s with type 2 diabetes mellitus had persistent right-sided watery nasal discharge for 6 months following cerebrospinal fluid (CSF) leak repair at another hospital, prompting his visit to us due to recurring symptoms. Imaging revealed a CSF leak from the mid-clivus for which revision endoscopic CSF leak repair was done. Regrettably, he developed postoperative meningitis caused by multidrug-resistant (MDR) Klebsiella pneumoniaeManaging this complex case was a challenging task due to the pathogen's resistance to conventional drugs and the scarcity of scientific evidence. We initiated a culture-guided combination regimen with ceftazidime, avibactam, aztreonam and tigecycline. This decision stemmed from meticulous literature review and observed antibiotic synergy while testing for this organism.After 4 weeks of vigilant treatment, the patient's symptoms improved significantly, and CSF cultures were sterile. We present our approach to effectively confront and manage a challenging instance of postoperative MDR bacterial meningitis.


Assuntos
Antibacterianos , Farmacorresistência Bacteriana Múltipla , Infecções por Klebsiella , Klebsiella pneumoniae , Meningites Bacterianas , Humanos , Masculino , Infecções por Klebsiella/tratamento farmacológico , Infecções por Klebsiella/microbiologia , Meningites Bacterianas/tratamento farmacológico , Meningites Bacterianas/microbiologia , Antibacterianos/uso terapêutico , Vazamento de Líquido Cefalorraquidiano/terapia , Adulto , Complicações Pós-Operatórias/tratamento farmacológico , Complicações Pós-Operatórias/microbiologia , Ceftazidima/uso terapêutico , Ceftazidima/administração & dosagem , Fossa Craniana Posterior/cirurgia , Aztreonam/uso terapêutico , Aztreonam/administração & dosagem , Tigeciclina/uso terapêutico , Tigeciclina/administração & dosagem , Combinação de Medicamentos , Compostos Azabicíclicos
3.
Front Cell Infect Microbiol ; 14: 1410834, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38903939

RESUMO

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 , Mutação
4.
Emerg Microbes Infect ; 13(1): 2356146, 2024 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-38743401

RESUMO

Ceftazidime-avibactam (CZA) is employed for the treatment of infections caused by Klebsiella pneumoniae carbapenemase-producing K. pneumoniae (KPC-KP). Resistance to CZA is frequently linked to point mutations in the blaKPC. We conducted in vitro simulations of in vivo blaKPC mutations using CZA. Four pre-therapy KPC-KP isolates (K1, K2, K3, and K4) were evaluated, all initially exhibited susceptibility to CZA and produced KPC-2. The crucial distinction was that following CZA treatment, the blaKPC-2 mutated in K1, K2, and K3, rendering them resistant to CZA, while K4 achieved microbiological clearance, and blaKPC-2 remained unaltered. The induction assay identified various blaKPC-2 variants, including blaKPC-25, blaKPC-127, blaKPC-100, blaKPC-128, blaKPC-137, blaKPC-138, blaKPC-144 and blaKPC-180. Our findings suggest that the resistance of KPC-KP to CZA primarily results from the emergence of KPC variants, complemented by increased blaKPC expression. A close correlation exists between avibactam concentration and the rate of increased CZA minimum Inhibitory concentration, as well as blaKPC mutation. Inadequate avibactam concentration is more likely to induce resistance in strains against CZA, there is also a higher likelihood of mutation in the blaKPC-2 and the optimal avibactam ratio remains to be determined. Simultaneously, we selected a blaKPC-33-producing K. pneumoniae strain (mutated from blaKPC-2) and induced it with imipenem and meropenem, respectively. The blaKPC-2 was detected during the process, indicating that the mutation is reversible. Clinical use of carbapenems to treat KPC variant strains increases the risk of infection, as the gene can mutate back to blaKPC-2, rendering the strain even more cross-resistant to carbapenems and CZA.


Assuntos
Antibacterianos , Compostos Azabicíclicos , Proteínas de Bactérias , Ceftazidima , Combinação de Medicamentos , Klebsiella pneumoniae , Testes de Sensibilidade Microbiana , beta-Lactamases , Ceftazidima/farmacologia , Compostos Azabicíclicos/farmacologia , beta-Lactamases/genética , beta-Lactamases/metabolismo , Klebsiella pneumoniae/genética , Klebsiella pneumoniae/efeitos dos fármacos , Antibacterianos/farmacologia , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Humanos , Mutação , Infecções por Klebsiella/microbiologia , Infecções por Klebsiella/tratamento farmacológico , Fenótipo , Hidrólise , Cinética
5.
Emerg Microbes Infect ; 13(1): 2361007, 2024 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-38801099

RESUMO

Ceftazidime-avibactam resistance attributable to the blaKPC-2 gene mutation is increasingly documented in clinical settings. In this study, we characterized the mechanisms leading to the development of ceftazidime-avibactam resistance in ST11-K47 hypervirulent Klebsiella pneumoniae that harboured the blaKPC-135 gene. This strain possessed fimbriae and biofilm, demonstrating pathogenicity. Compared with the wild-type KPC-2 carbapenemase, the novel KPC-135 enzyme exhibited a deletion of Glu168 and Leu169 and a 15-amino acid tandem repeat between Val262 and Ala276. The blaKPC-135 gene was located within the Tn6296 transposon truncated by IS26 and carried on an IncFII/IncR-type plasmid. Compared to the blaKPC-2-positive cloned strain, only the MIC of ceftazidime increased against blaKPC-135-positive K. pneumoniae and wasn't inhibited by avibactam (MIC 32 µg/mL), while clavulanic acid and vaborbactam demonstrated some inhibition. Kinetic parameters revealed that KPC-135 exhibited a lower Km and kcat/Km with ceftazidime and carbapenems, and a higher (∼26-fold) 50% inhibitory concentration with avibactam compared to KPC-2. The KPC-135 enzyme exerted a detrimental effect on fitness relative to the wild-type strain. Furthermore, this strain possessed hypervirulent determinants, which included the IncHI1B/FIB plasmid with rmpA2 and expression of type 1 and 3 fimbriae. In conclusion, we reported a novel KPC variant, KPC-135, in a clinical ST11-K47 hypervirulent K. pneumoniae strain, which conferred ceftazidime-avibactam resistance, possibly through increased ceftazidime affinity and decreased avibactam susceptibility. This strain simultaneously harboured resistance and virulence genes, posing an elevated challenge in clinical treatment.


Assuntos
Antibacterianos , Compostos Azabicíclicos , Proteínas de Bactérias , Ceftazidima , Combinação de Medicamentos , Infecções por Klebsiella , Klebsiella pneumoniae , Testes de Sensibilidade Microbiana , beta-Lactamases , Ceftazidima/farmacologia , Klebsiella pneumoniae/genética , Klebsiella pneumoniae/efeitos dos fármacos , Klebsiella pneumoniae/patogenicidade , Klebsiella pneumoniae/enzimologia , Compostos Azabicíclicos/farmacologia , Antibacterianos/farmacologia , Infecções por Klebsiella/microbiologia , Infecções por Klebsiella/tratamento farmacológico , beta-Lactamases/genética , beta-Lactamases/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Humanos , Virulência , Biofilmes/efeitos dos fármacos , Biofilmes/crescimento & desenvolvimento , Farmacorresistência Bacteriana Múltipla/genética , Plasmídeos/genética , Animais
6.
Microbiol Spectr ; 12(6): e0410523, 2024 Jun 04.
Artigo em Inglês | MEDLINE | ID: mdl-38700337

RESUMO

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 farmacológico
7.
Front Cell Infect Microbiol ; 14: 1404404, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38779560

RESUMO

Background: Ceftazidime-avibactam is a treatment option for carbapenem-resistant gram-negative bacilli (CR-GNB) infections. However, the risk factors associated with ceftazidime-avibactam (CAZ-AVI) treatment failure in kidney transplant (KT) recipients and the need for CAZ-AVI-based combination therapy remain unclear. Methods: From June 2019 to December 2023, a retrospective observational study of KT recipients with CR-GNB infection treated with CAZ-AVI was conducted, with the primary outcome being 30-day mortality and secondary outcomes being clinical cure, microbiological cure, and safety. Risk factors for 30-day mortality and clinical failure were also investigated. Results: A total of 81 KT recipients treated with CAZ-AVI were included in this study. Forty recipients (49.4%) received CAZ-AVI monotherapy, with a 30-day mortality of 22.2%. The clinical cure and microbiological cure rates of CAZ/AVI therapy were 72.8% and 66.7%, respectively. CAZ-AVI alone or in combination with other medications had no effect on clinical cure or 30-day mortality. Multivariate logistic regression analysis revealed that a higher Acute Physiology and Chronic Health Evaluation (APACHE) II score (odds ratio [OR]: 4.517; 95% confidence interval [CI]: 1.397-14.607; P = 0.012) was an independent risk factor for 30-day mortality. Clinical cure was positively associated with the administration of CAZ-AVI within 48 hours of infection onset (OR: 11.009; 95% CI: 1.344-90.197; P=0.025) and negatively associated with higher APACHE II scores (OR: 0.700; 95% CI: 0.555-0.882; P=0.002). Four (4.9%) recipients experienced recurrence within 90 days after the initial infection, 3 (3.7%) recipients experienced CAZ-AVI-related adverse events, and no CAZ-AVI resistance was identified. Conclusion: CAZ-AVI is an effective medication for treating CR-GNB infections following kidney transplantation, even as monotherapy. Optimization of CAZ/AVI therapy (used within 48 hours of infection onset) is positively associated with potential clinical benefit. Further larger-scale studies are needed to validate these findings.


Assuntos
Antibacterianos , Compostos Azabicíclicos , Carbapenêmicos , Ceftazidima , Combinação de Medicamentos , Infecções por Bactérias Gram-Negativas , Transplante de Rim , Humanos , Transplante de Rim/efeitos adversos , Estudos Retrospectivos , Ceftazidima/uso terapêutico , Ceftazidima/farmacologia , Masculino , Feminino , Pessoa de Meia-Idade , Fatores de Risco , Compostos Azabicíclicos/uso terapêutico , Infecções por Bactérias Gram-Negativas/tratamento farmacológico , Infecções por Bactérias Gram-Negativas/mortalidade , Antibacterianos/uso terapêutico , Antibacterianos/farmacologia , Carbapenêmicos/uso terapêutico , Carbapenêmicos/farmacologia , Adulto , Bactérias Gram-Negativas/efeitos dos fármacos , Resultado do Tratamento , Idoso , Transplantados
8.
Microb Pathog ; 192: 106668, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38697232

RESUMO

OBJECTIVES: The emergence of carbapenem-resistant Pseudomonas putida (CRPP) has raised public awareness. This study investigated two strains from the Pseudomonas putida group that were resistant to carbapenem, tigecycline, and aztreonam-avibactam (ATM-AVI), with a focus on their microbial and genomic characteristics. METHODS: We assessed the antibiotic resistance profile using broth dilution, disk diffusion, and E-test methods. Efflux pump phenotype testing and real-time quantitative PCR were employed to evaluate efflux pump activity in tigecycline resistance, while polymerase chain reaction was utilized to detect common carbapenem genes. Additionally, whole-genome sequencing was performed to analyze genomic characteristics. The transferability of blaIMP-1 and blaAFM-4 was assessed through a conjugation experiment. Furthermore, growth kinetics and biofilm formation were examined using growth curves and crystal violet staining. RESULTS: Both strains demonstrated resistance to carbapenem, tigecycline, and ATM-AVI. Notably, NMP can restore sensitivity to tigecycline. Subsequent analysis revealed that they co-produced blaIMP-1, blaAFM-4, tmexCD-toprJ, and blaOXA-1041, belonging to a novel sequence type ST268. Although they were closely related on the phylogenetic tree, they exhibited different levels of virulence. Genetic environment analysis indicated variations compared to prior studies, particularly regarding the blaIMP-1 and blaAFM-4 genes, which showed limited horizontal transferability. Moreover, it was observed that temperature exerted a specific influence on their biological factors. CONCLUSION: We initially identified two P. putida ST268 strains co-producing blaIMP-1, blaAFM-4, blaOXA-1041, and tmexCD-toprJ. The resistance to tigecycline and ATM-AVI can be attributed to the presence of multiple drug resistance determinants. These findings underscore the significance of P. putida as a reservoir for novel antibiotic resistance genes. Therefore, it is imperative to develop alternative antibiotic therapies and establish effective monitoring of bacterial resistance.


Assuntos
Antibacterianos , Compostos Azabicíclicos , Aztreonam , Testes de Sensibilidade Microbiana , Pseudomonas putida , Tigeciclina , beta-Lactamases , Pseudomonas putida/genética , Pseudomonas putida/efeitos dos fármacos , Tigeciclina/farmacologia , Antibacterianos/farmacologia , China , Aztreonam/farmacologia , Compostos Azabicíclicos/farmacologia , beta-Lactamases/genética , beta-Lactamases/metabolismo , Farmacorresistência Bacteriana Múltipla/genética , Sequenciamento Completo do Genoma , Humanos , Combinação de Medicamentos , Biofilmes/efeitos dos fármacos , Biofilmes/crescimento & desenvolvimento , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Infecções por Pseudomonas/microbiologia , Carbapenêmicos/farmacologia
9.
Indian J Med Microbiol ; 49: 100603, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38705276

RESUMO

OBJECTIVE: To find the prevalence of Ceftazidime-Avibactam (CAZ-AVI) resistant Klebsiella pneumoniae in clinical isolates and to determine the genes responsible for Ceftazidime-Avibactam resistance using PCR. METHODS: A total of 89 carbapenem resistant Klebsiella pneumoniae from various clinical samples were included in the study. CAZ-AVI resistance was tested using E-test. CAZ-AVI resistant strains were subjected to conventional PCR for detection of carbapenamase genes blaNDM- 1, blaOXA-48, blaVIM, blaIMP, blaKPC. RESULTS: Of the 89 isolates screened for CAZ-AVI resistance, 45(50.5%) isolates were found to be resistant. 42 isolates were subjected to PCR for detection of ß lactamase genes.34 isolates were positive for blaNDM-1 and all 42 isolates were positive for blaOXA-48. Co-expression of NDM-1 and OXA-48 was seen in 34 isolates. Sensitivity of mCIM test to identify a carbapenamse compared to PCR was 61.9%. Sensitivity of eCIM test to identify NDM-1 was 80%. CONCLUSION: CAZ-AVI was effective in vitro in 49.4% of the isolates. Indicating that CAZ-AVI is a promising addition to antibiotics against CRE as well as a carbapenem sparing drug in ESBL producing organisms. ß-Lactamase-related mutations are the main mechanism leading to CAZ-AVI resistance.


Assuntos
Antibacterianos , Compostos Azabicíclicos , Ceftazidima , Combinação de Medicamentos , Infecções por Klebsiella , Klebsiella pneumoniae , Testes de Sensibilidade Microbiana , beta-Lactamases , Ceftazidima/farmacologia , Compostos Azabicíclicos/farmacologia , Humanos , Klebsiella pneumoniae/genética , Klebsiella pneumoniae/efeitos dos fármacos , Klebsiella pneumoniae/isolamento & purificação , beta-Lactamases/genética , Infecções por Klebsiella/microbiologia , Antibacterianos/farmacologia , Genótipo , Enterobacteriáceas Resistentes a Carbapenêmicos/genética , Enterobacteriáceas Resistentes a Carbapenêmicos/efeitos dos fármacos , Enterobacteriáceas Resistentes a Carbapenêmicos/isolamento & purificação , Proteínas de Bactérias/genética , Carbapenêmicos/farmacologia , Farmacorresistência Bacteriana Múltipla/genética , Reação em Cadeia da Polimerase
10.
Diagn Microbiol Infect Dis ; 109(3): 116344, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38735147

RESUMO

Combinations of the ß-lactam/ß-lactamase inhibitor sulbactam-durlobactam and seventeen antimicrobial agents were tested against strains of Acinetobacter baumannii in checkerboard assays. Most combinations resulted in indifference with no instances of antagonism. These results suggest sulbactam-durlobactam antibacterial activity against A. baumannii is unlikely to be affected if co-dosed with other antimicrobial agents.


Assuntos
Acinetobacter baumannii , Antibacterianos , Compostos Azabicíclicos , Testes de Sensibilidade Microbiana , Sulbactam , Sulbactam/farmacologia , Acinetobacter baumannii/efeitos dos fármacos , Compostos Azabicíclicos/farmacologia , Antibacterianos/farmacologia , Humanos , Acinetobacter calcoaceticus/efeitos dos fármacos , Inibidores de beta-Lactamases/farmacologia , Infecções por Acinetobacter/microbiologia , Infecções por Acinetobacter/tratamento farmacológico , Combinação de Medicamentos
11.
Front Cell Infect Microbiol ; 14: 1352339, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38808066

RESUMO

Antibiotic drug combination therapy is critical for the successful treatment of infections caused by multidrug resistant pathogens. We investigated the efficacy of ß-lactam and ß-lactam/ß-lactamase inhibitor combinations with other antibiotics, against the hypervirulent, ceftazidime/avibactam resistant Pseudomonas aeruginosa Liverpool epidemic strain (LES) B58. Although minimum inhibitory concentrations in vitro differed by up to eighty-fold between standard and host-mimicking media, combinatorial effects only marginally changed between conditions for some combinations. Effective combinations in vitro were further tested in a chronic, high-density murine infection model. Colistin and azithromycin demonstrated combinatorial effects with ceftazidime and ceftazidime/avibactam both in vitro and in vivo. Conversely, while tobramycin and tigecycline exhibited strong synergy in vitro, this effect was not observed in vivo. Our approach of using host-mimicking conditions and a sophisticated animal model to evaluate drug synergy against bacterial pathogens represents a promising approach. This methodology may offer insights into the prediction of combination therapy outcomes and the identification of potential treatment failures.


Assuntos
Abscesso , Antibacterianos , Modelos Animais de Doenças , Sinergismo Farmacológico , Quimioterapia Combinada , Testes de Sensibilidade Microbiana , Infecções por Pseudomonas , Pseudomonas aeruginosa , Animais , Pseudomonas aeruginosa/efeitos dos fármacos , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Infecções por Pseudomonas/tratamento farmacológico , Infecções por Pseudomonas/microbiologia , Camundongos , Abscesso/tratamento farmacológico , Abscesso/microbiologia , Combinação de Medicamentos , Farmacorresistência Bacteriana Múltipla , Feminino , Ceftazidima/farmacologia , Ceftazidima/uso terapêutico , Azitromicina/farmacologia , Azitromicina/uso terapêutico , Azitromicina/administração & dosagem , Compostos Azabicíclicos/farmacologia , Compostos Azabicíclicos/uso terapêutico , Colistina/farmacologia , Colistina/uso terapêutico , Colistina/administração & dosagem
12.
Microbiol Spectr ; 12(6): e0010724, 2024 Jun 04.
Artigo em Inglês | MEDLINE | ID: mdl-38712934

RESUMO

This study aimed to assess the in vitro efficacy of ceftazidime-avibactam (CZA) in combination with various antimicrobial agents against carbapenem-resistant Klebsiella pneumoniae (CRKP). We selected 59 clinical CRKP isolates containing distinct drug resistance mechanisms. The minimum inhibitory concentrations (MICs) of meropenem (MEM), colistin (COL), eravacycline (ERA), amikacin (AK), fosfomycin (FOS), and aztreonam (ATM), both individually and in combination with CZA, were tested using the checkerboard method. The interactions of antimicrobial agent combinations were assessed by fractional inhibitory concentration index (FICI) and susceptible breakpoint index (SBPI). The time-kill curve assay was employed to dynamically evaluate the effects of these drugs alone and in combination format. In the checkerboard assay, the combination of CZA+MEM showed the highest level of synergistic effect against both KPC-producing and carbapenemase-non-producing isolates, with synergy rates of 91.3% and 100%, respectively. Following closely was the combination of FOS+CZA . For metallo-beta-lactamases (MBLs) producing strains, ATM+CZA displayed complete synergy, while the combination of MEM+CZA showed a synergy rate of only 57.14% for NDM-producing strains and 91.67% for IMP-producing strains. In the time-kill assay, MEM+CZA also demonstrated significant synergistic effects against the two KPC-2-producing isolates (Y070 and L70), the two carbapenemase-non-producing isolates (Y083 and L093), and the NDM-1-producing strain L13, with reductions in log10 CFU/mL exceeding 10 compared to the control. Against the IMP-producing strain Y047, ATM+CZA exhibited the highest synergistic effect, resulting in a log10 CFU/mL reduction of 10.43 compared to the control. The combination of CZA and MEM exhibited good synergistic effects against KPC-producing and non-enzyme-producing strains, followed by the FOS+CZA combination. Among MBL-producing strains, ATM+CZA demonstrated the most pronounced synergistic effect. However, the combinations of CZA with ERA, AK, and COL show irrelevant effects against the tested clinical isolates. IMPORTANCE: Our study confirmed the efficacy of the combination CZA+MEM against KPC-producing and non-carbapenemase-producing strains. For metalloenzyme-producing strains, CZA+ATM demonstrated the most significant synergy. Additionally, CZA exhibited a notable synergy effect when combined with FOS. These combination therapies present promising new options for the treatment of CRKP infection.


Assuntos
Antibacterianos , Compostos Azabicíclicos , Enterobacteriáceas Resistentes a Carbapenêmicos , Ceftazidima , Combinação de Medicamentos , Sinergismo Farmacológico , Infecções por Klebsiella , Klebsiella pneumoniae , Testes de Sensibilidade Microbiana , Compostos Azabicíclicos/farmacologia , Klebsiella pneumoniae/efeitos dos fármacos , Klebsiella pneumoniae/genética , Ceftazidima/farmacologia , Humanos , Antibacterianos/farmacologia , Infecções por Klebsiella/tratamento farmacológico , Infecções por Klebsiella/microbiologia , Enterobacteriáceas Resistentes a Carbapenêmicos/efeitos dos fármacos , beta-Lactamases/metabolismo , beta-Lactamases/genética , Carbapenêmicos/farmacologia , Farmacorresistência Bacteriana Múltipla , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Fosfomicina/farmacologia , Aztreonam/farmacologia
13.
Virulence ; 15(1): 2348251, 2024 12.
Artigo em Inglês | MEDLINE | ID: mdl-38697754

RESUMO

OBJECTIVES: This study aimed at revealing the underlying mechanisms of the loss and gain of ceftazidime-avibactam susceptibility in a non-carbapenemase-producing hypervirulent Klebsiella pneumoniae (hvKp). METHODS: Here we longitudinally recovered 3 non-carbapenemase-producing K1-ST23 hvKp strains at a one-month interval (KP29105, KP29499 and KP30086) from an elderly male. Antimicrobial susceptibility testing, whole genome sequencing, transcriptomic sequencing, gene cloning, plasmid conjugation, quantitative real-time PCR (qRT-PCR), and SDS-PAGE (sodium dodecyl sulfate-polyacrylamide gel electrophoresis) were conducted. RESULTS: Among the 3 hvKp strains, KP29105 was resistant to the third- and fourth-generation cephalosporins, KP29499 acquired resistance to both ceftazidime-avibactam and carbapenems, while KP30086 restored its susceptibility to ceftazidime-avibactam, imipenem and meropenem but retained low-level resistance to ertapenem. KP29105 and KP29499 carried plasmid-encoded genes blaCTX-M-15 and blaCTX-M-71, respectively, but KP30086 lost both. Cloning of gene blaCTX-M-71 and conjugation experiment of blaCTX-M-71-carrying plasmid showed that the transformant and transconjugant were susceptible to ceftazidime-avibactam but had a more than 8-fold increase in MICs. Supplementation with an outer membrane permeabilizer could reduce the MIC of ceftazidime-avibactam by 32 folds, indicating that porins play a key role in ceftazidime-avibactam resistance. The OmpK35 of the 3 isolates was not expressed, and the OmpK36 of KP29499 and KP30086 had a novel amino acid substitution (L359R). SDS-PAGE and qRT-PCR showed that the expression of porin OmpK36 of KP29499 and KP30086 was significantly down-regulated compared with KP29105. CONCLUSIONS: In summary, we reported the rare ceftazidime-avibactam resistance in a non-carbapenemase-producing hvKp strain. Resistance plasmid carrying blaCTX-M-71 and mutated OmpK36 had a synergetic effect on the resistance.


Assuntos
Antibacterianos , Compostos Azabicíclicos , Proteínas de Bactérias , Ceftazidima , Combinação de Medicamentos , Infecções por Klebsiella , Klebsiella pneumoniae , Testes de Sensibilidade Microbiana , Ceftazidima/farmacologia , Klebsiella pneumoniae/genética , Klebsiella pneumoniae/efeitos dos fármacos , Klebsiella pneumoniae/patogenicidade , Klebsiella pneumoniae/enzimologia , Compostos Azabicíclicos/farmacologia , Antibacterianos/farmacologia , Masculino , Infecções por Klebsiella/microbiologia , Infecções por Klebsiella/tratamento farmacológico , Humanos , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , beta-Lactamases/genética , beta-Lactamases/metabolismo , Idoso , Farmacorresistência Bacteriana Múltipla/genética , Virulência , Plasmídeos/genética , Sequenciamento Completo do Genoma
14.
PLoS One ; 19(5): e0303753, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38758757

RESUMO

NDM-producing carbapenem-resistant bacterial infections became a challenge for clinicians. Combination therapy of aztreonam and ceftazidime-avibactam is a prudent choice for these infections. However, there is still no recommendation of a practically feasible method for testing aztreonam and ceftazidime-avibactam synergy. We proposed a simple method for testing aztreonam and ceftazidime-avibactam synergy and compared it with reference broth micro-dilution and other methods. Carbapenem-resistant Enterobacterales clinical isolates were screened for the presence of the NDM gene by the Carba R test. NDM harbouring isolates were tested for aztreonam and ceftazidime-avibactam synergy by broth microdilution (reference method), E strip-disc diffusion, double disc diffusion, and disc replacement methods. In the newly proposed method, the MHA medium was supplemented with ceftazidime-avibactam (corresponding to an aztreonam concentration of 4µg/ml). The MHA medium was then inoculated with the standard inoculum (0.5 McFarland) of the test organism. An AZT disc (30 µg) was placed on the supplemented MHA medium, and the medium was incubated overnight at 37°C. Aztreonam zone diameter on the supplemented MHA medium (in the presence of ceftazidime-avibactam) was compared with that from a standard disc diffusion plate (without ceftazidime-avibactam), performed in parallel. Interpretation of synergy was based on the restoration of aztreonam zone diameter (in the presence of ceftazidime-avibactam) crossing the CLSI susceptibility breakpoint, i.e., ≥ 21 mm. Of 37 carbapenem-resistant NDM-producing isolates, 35 (94.6%) were resistant to aztreonam and tested synergy positive by the proposed method. Its sensitivity and specificity were 97.14% and 100%, respectively. Cohen's kappa value showed substantial agreement of the reference method with the proposed method (κ = 0.78) but no other methods. The proposed method is simple, easily interpretable, and showed excellent sensitivity, specificity, and agreement with the reference method. Therefore, the new method is feasible and reliable for testing aztreonam synergy with avibactam in NDM-producing Enterobacterales.


Assuntos
Antibacterianos , Compostos Azabicíclicos , Aztreonam , Ceftazidima , Combinação de Medicamentos , Enterobacteriaceae , Testes de Sensibilidade Microbiana , beta-Lactamases , Ceftazidima/farmacologia , Aztreonam/farmacologia , Compostos Azabicíclicos/farmacologia , beta-Lactamases/metabolismo , beta-Lactamases/genética , Testes de Sensibilidade Microbiana/métodos , Antibacterianos/farmacologia , Enterobacteriaceae/efeitos dos fármacos , Enterobacteriaceae/enzimologia , Enterobacteriaceae/genética , Humanos , Sinergismo Farmacológico , Infecções por Enterobacteriaceae/microbiologia , Infecções por Enterobacteriaceae/tratamento farmacológico
15.
Ann Clin Microbiol Antimicrob ; 23(1): 47, 2024 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-38796461

RESUMO

BACKGROUND: Aztreonam-avibactam (ATM-AVI) combination shows promising effectiveness on most carbapenemase-producing Gram-negatives, yet standardized antibiotic susceptibility testing (AST) methods for evaluating the combination in clinical laboratories is lacking. We aimed to evaluate different ATM-AVI AST approaches. METHODS: 96 characterized carbapenem-resistant clinical isolates belonging to 9 Enterobacterales (EB; n = 80) and P. aeruginosa (PA; n = 16) species, including 90 carbapenemase producers and 72 strains resistant to both CAZ-AVI and ATM, were tested. Paper disk elution (DE; Bio-Rad) and E-test gradient strips stacking (SS; bioMérieux) were performed for the ATM + CAZ-AVI combination. MIC Test Strip (MTS; Liofilchem) was evaluated for ATM-AVI MIC determination. Results were interpreted applying ATM clinical breakpoints of the EUCAST guidelines and compared to the broth microdilution method (Sensititre, Thermofisher). RESULTS: According to broth microdilution method, 93% of EB and 69% of PA were tested susceptible to ATM-AVI. The synergistic effect of ATM-AVI was of 95% for EB, but of only 17% for PA. The MTS method yielded higher categorical and essential agreement (CA/EA) rates for both EB (89%/91%) and PA (94%/94%) compared to SS, where the rates were 87%/83% for EB and 81%/81% for PA. MTS and SS yielded 2 and 3 major discrepancies, respectively, while 3 very major discrepancies each were observed for both methods. Concerning the DE method, CA reached 91% for EB and 81% for PA, but high number of very major discrepancies were observed for EB (n = 6; 8%) and for PA (n = 3; 19%). CONCLUSIONS: The ATM-AVI association displayed excellent in vitro activity against highly resistant clinical Enterobacterales strains. MTS method offers accurate ATM-AVI AST results, while the SS method might serve as better alternative then DE method in assessing the efficacy of ATM + CAZ-AVI combination. However, further investigation is needed to confirm the methods' ability to detect ATM-AVI resistance.


Assuntos
Antibacterianos , Compostos Azabicíclicos , Aztreonam , Farmacorresistência Bacteriana Múltipla , Bactérias Gram-Negativas , Testes de Sensibilidade Microbiana , Aztreonam/farmacologia , Compostos Azabicíclicos/farmacologia , Testes de Sensibilidade Microbiana/métodos , Antibacterianos/farmacologia , Humanos , Bactérias Gram-Negativas/efeitos dos fármacos , Combinação de Medicamentos , Pseudomonas aeruginosa/efeitos dos fármacos , beta-Lactamases/metabolismo , Enterobacteriaceae/efeitos dos fármacos , Proteínas de Bactérias , Infecções por Bactérias Gram-Negativas/microbiologia
16.
PLoS One ; 19(4): e0298577, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38635685

RESUMO

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/genética
17.
J Microbiol Immunol Infect ; 57(3): 457-469, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38584042

RESUMO

INTRODUCTION: Aim of the study was the molecular characterization of 21 ceftazidime/avibactam resistant (CZA-R) Klebsiella pneumoniae strains, collected in the period October 2021-March 2022 from an Intensive Care COVID Unit in a Northern Italian Hospital. METHODS: After growth on selective/chromogenic culture media and susceptibility tests assessment, resistance genes content was ascertained for all the isolates by the HybriSpot 12 multiplexing, PCR and Whole-Genome Sequencing (WGS). Clonality was assessed by PFGE and MLST according to the Pasteur scheme. A SNPs-based phylogenetic tree was obtained comparing representative isolates and global genomes. The blaKPC gene horizontal transmission was evaluated by conjugation experiments. blaKPC-166 was cloned in a pCR2.1 vector and transformed in chemically competent TOP10 cells. RESULTS: Sixteen inpatients resulted positive for colonization and/or infection by KPC-producing K. pneumoniae (KPC-Kp) strains. The 21 CZA-R KPC-Kp isolates obtained showed MDR phenotype; susceptibility to meropenem was always retained. All the CZA-R KPC-Kp presented a novel blaKPC variant, named blaKPC-166, showing a single nucleotide substitution (T811C) compared to the blaKPC-94; but related to blaKPC-2. TWO DIFFERENT PULSOTYPES WERE DETECTED: A in 18/21 and B in 1/21 cases, two strains from the same patient being untypable by PFGE. Interestingly, the outbreak was sustained by the high-risk clone ST307, although the ST22, ST6342, ST6418 and ST6811 have also been identified and associated to KPC-166. Worryingly, blaKPC-166 could be transferred horizontally and, after cloning, it conferred resistance to CZA. DISCUSSION: This novel variant confers CZA-resistance and carbapenems susceptibility restoration. As KPC-166 was found expressed by multiple Kp clones, greater efforts should be made to prevent the further dissemination of such strains in Italian clinical settings.


Assuntos
Antibacterianos , Compostos Azabicíclicos , Ceftazidima , Surtos de Doenças , Combinação de Medicamentos , Unidades de Terapia Intensiva , Infecções por Klebsiella , Klebsiella pneumoniae , Testes de Sensibilidade Microbiana , beta-Lactamases , Klebsiella pneumoniae/genética , Klebsiella pneumoniae/efeitos dos fármacos , Klebsiella pneumoniae/isolamento & purificação , Humanos , Ceftazidima/farmacologia , Ceftazidima/uso terapêutico , Itália/epidemiologia , Infecções por Klebsiella/epidemiologia , Infecções por Klebsiella/microbiologia , Infecções por Klebsiella/tratamento farmacológico , Compostos Azabicíclicos/farmacologia , beta-Lactamases/genética , Antibacterianos/farmacologia , Farmacorresistência Bacteriana Múltipla/genética , COVID-19/epidemiologia , COVID-19/virologia , COVID-19/microbiologia , Filogenia , Proteínas de Bactérias/genética , Sequenciamento Completo do Genoma , Masculino , Tipagem de Sequências Multilocus , Feminino
19.
ACS Infect Dis ; 10(5): 1767-1779, 2024 05 10.
Artigo em Inglês | MEDLINE | ID: mdl-38619138

RESUMO

Peptidoglycan synthesis is an underutilized drug target in Mycobacterium tuberculosis (Mtb). Diazabicyclooctanes (DBOs) are a class of broad-spectrum ß-lactamase inhibitors that also inhibit certain peptidoglycan transpeptidases that are important in mycobacterial cell wall synthesis. We evaluated the DBO durlobactam as an inhibitor of BlaC, the Mtb ß-lactamase, and multiple Mtb peptidoglycan transpeptidases (PonA1, LdtMt1, LdtMt2, LdtMt3, and LdtMt5). Timed electrospray ionization mass spectrometry (ESI-MS) captured acyl-enzyme complexes with BlaC and all transpeptidases except LdtMt5. Inhibition kinetics demonstrated durlobactam was a potent and efficient DBO inhibitor of BlaC (KI app 9.2 ± 0.9 µM, k2/K 5600 ± 560 M-1 s-1) and similar to clavulanate (KI app 3.3 ± 0.6 µM, k2/K 8400 ± 840 M-1 s-1); however, durlobactam had a lower turnover number (tn = kcat/kinact) than clavulanate (1 and 8, respectively). KI app values with durlobactam and clavulanate were similar for peptidoglycan transpeptidases, but ESI-MS captured durlobactam complexes at more time points. Molecular docking and simulation demonstrated several productive interactions of durlobactam in the active sites of BlaC, PonA1, and LdtMt2. Antibiotic susceptibility testing was conducted on 11 Mtb isolates with amoxicillin, ceftriaxone, meropenem, imipenem, clavulanate, and durlobactam. Durlobactam had a minimum inhibitory concentration (MIC) range of 0.5-16 µg/mL, similar to the ranges for meropenem (1-32 µg/mL) and imipenem (0.5-64 µg/mL). In ß-lactam + durlobactam combinations (1:1 mass/volume), MICs were lowered 4- to 64-fold for all isolates except one with meropenem-durlobactam. This work supports further exploration of novel ß-lactamase inhibitors that target BlaC and Mtb peptidoglycan transpeptidases.


Assuntos
Aminoaciltransferases , Antituberculosos , Mycobacterium tuberculosis , Inibidores de beta-Lactamases , beta-Lactamases , Aminoaciltransferases/antagonistas & inibidores , Antituberculosos/farmacologia , Antituberculosos/química , Compostos Azabicíclicos/farmacologia , Compostos Azabicíclicos/química , Proteínas de Bactérias/antagonistas & inibidores , Proteínas de Bactérias/química , Inibidores de beta-Lactamases/farmacologia , Inibidores de beta-Lactamases/química , beta-Lactamases/metabolismo , beta-Lactamases/química , Cinética , Testes de Sensibilidade Microbiana , Simulação de Acoplamento Molecular , Mycobacterium tuberculosis/efeitos dos fármacos , Mycobacterium tuberculosis/enzimologia
20.
J Glob Antimicrob Resist ; 37: 190-194, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38588973

RESUMO

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 , Adulto
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