Journal of global antimicrobial resistance最新文献

Objective: Raoultella planticola is an emerging opportunistic pathogen closely related to members of the Klebsiella genus. Genomic characterization of R. planticola isolates recovered from food animals is lacking. Here we describe the antimicrobial resistance genes, virulence factors, plasmid replicons, and phylogeny of three antimicrobial-resistant R. planticola isolates recovered from the feces of three dairy calves within 48 hours of birth.

Methods: The genomes of the three R. planticola isolates were sequenced on a NextSeq 2000 platform using paired-end sequencing. The raw reads were trimmed using Trimmomatic and assembled using SPAdes v 3.15.4. Antimicrobial resistance genes, virulence factors and plasmid replicons were identified using ABRicate. Single nucleotide polymorphisms were identified among the genomes using the Harvest package and phylogenies were inferred using RAxML.

Results: In total, nine different ARGs known to confer resistance to at least five different classes of antibiotics were detected among the three R. planticola genomes. These include bla_PLA, a β-lactamase found only in R. planticola, fosfomycin resistance gene fosA, and a sequence aligned with oxqAB, an efflux pump conferring resistance to antibiotics including fluoroquinolones. Each genome encoded between four and seven ARGs, with three considered genotypically to be multidrug-resistant (MDR). Two of the three genomes harbored plasmids, and all three encoded 41 to 42 virulence factors, including iron scavenging genes sitABCD.

Conclusions: Results of this study demonstrate the presence of diverse antimicrobial-resistant R. planticola, isolated from the feces of healthy dairy calves, that had some virulence factors that may cause human disease.

Background: This study aims to investigate the effectiveness of UIO-66-NH₂, a metal-organic framework (MOF), as a carrier for imipenem/cilastatin (Imp/Cil) in overcoming resistance in clinical isolates of imipenem-resistant Pseudomonas aeruginosa.

Methods: The UIO-66-NH₂-Imp/Cil formulations were synthesized and characterized using dynamic light scattering (DLS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Drug entrapment efficiency of UIO-66-NH₂-Imp/Cil, and Imp/Cil release rates were determined. The stability of formulations was assessed by at room temperature and refrigeration for two months. The antibacterial, anti-biofilm and anti-virulence activities of formulations were investigated against imipenem-resistant Pseudomonas aeruginosa isolates.

Results: The UIO-66-NH₂-Imp/Cil formulation showed an average particle size of 212.3 ± 7.3 nm, a polydispersity index (PDI) of 0.142 ± 0.010, and an entrapment efficiency (EE%) of 74.19 ± 1.12%. Drug release from the formulation followed a Korsmeyer-Peppas kinetic model, with 52% of the drug released over 72 hours. Antibacterial testing indicated a significant decrease in minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) for the UIO-66-NH₂-Imp/Cil formulation compared to free Imp/Cil, demonstrating enhanced antibacterial activity. Furthermore, the anti-biofilm and anti-virulence activity of UIO-66-NH₂-Imp/Cil was confirmed by the reduction of bacterial hemolysis activity, minimal pyocyanin, EPS (extracellular polymeric substance) production, and lower metabolic activity of pathogens. Also, UIO-66-NH₂-Imp/Cil causes significant reduction in the expression of lasA, lasB and, rhlA genes, which resulted in the inhibition of quorum-sensing (QS) system activity.

Conclusion: These findings indicate that UIO-66-NH₂-Imp/Cil nanocarriers offer a promising new approach against multidrug-resistant Gram-negative pathogens, providing insights into potential mechanisms of antimicrobial action.

Background: Acinetobacter baumannii (Ab) causes severe infections among intensive care units (ICU) and mechanically ventilated patients. According to the European Centre for Disease Prevention and Control data for 2018 the prevalence of Ab in Polish ICUs was higher than in other European countries, while almost 40% of Ab were resistant to carbapenems (CR-Ab) in 2021. Our goal was to investigate the epidemiology and molecular characteristics of CR-Ab strains collected from the University Hospital in Krakow, Poland, by whole-genome sequencing (WGS) and phenotypic tests.

Methods: Epidemiological and drug-resistance data from a total of 667 hospital-acquired (HAI) CR-Ab infections collected in 2019 (442) and 2021 (235) were examined. Bacterial identification, antimicrobial susceptibility and detection of carbapenemases were performed. A selected subset of 125 CR-Ab isolated in 2021 was investigated by WGS.

Results: Among 125 CR-Ab isolates examined by WGS, the vast majority 104 (82%), belonged to the most prevalent ST2, and whereas 20 (16%) belonged to the rarely reported ST600. The most common genes conferring resistance to carbapenems were bla_OXA-66 (96.8%), and bla_OXA-72 (71.2%), whereas bla_OXA-23 and bla_NDM-1 genes were specific to ST600 isolates. The bla_NDM-1 gene was chromosomally located in IS30 of Tn125.

Conclusions: Our study reveals the presence of CR-Ab of the sporadically reported ST600 harbouring the bla_NDM-1 gene, reported for the first time in Poland. Routine genomic surveillance should be implemented to monitor and reduce the transmission of circulating resistant Ab clones.

Background: .Enterococcus spp. are typically found in multiple settings and are sometimes responsible for difficult-to-treat infections. In this context, very little is known about E. devriesei, a rare species first isolated from a river lamprey. Importantly, no complete genome of E. devriesei currently exists in public repositories.

Methods: . An E. devriesei strain (Ed-CK-24) was isolated from homogenized Zophobas morio larvae. Initial species identification (ID) was performed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Antimicrobial susceptibility testing (AST) was performed by broth microdilution. Whole-genome sequencing (WGS) was done using both Illumina NovaSeq 6000 and Nanopore MinION to generate a complete genome assembly. WGS data were used to confirm species ID, antimicrobial resistance genes (ARGs) and plasmid replicon sequences screening. A database search for other E. devriesei genomes in NCBI was performed and used for 16S rRNA and core-genome phylogeny analyses.

Results: . WGS and bioinformatic analyses were performed, resulting in a complete genome assembly and allowing accurate taxonomic classification of Ed-CK-24 strain as E. devriesei. Alignment of 16S rRNA sequences of representative Enterococcus spp. further supported the ID of Ed-CK-24. A core-genome phylogenetic analysis revealed no clonal relationships between Ed-CK-24 and other E. devriesei derived from multiple sources. The Ed-CK-24 strain was resistant to clindamycin and quinupristin/dalfopristin. ARG screening identified the lsa(A) gene, carried on a 633,497-bp circular megaplasmid.

Conclusions: . WGS of Ed-CK-24 allowed high-resolution genomic comparison and epidemiologic analysis of E. devriesei. Its isolation from Z. morio larvae, commonly used in pet food, warns for further surveillance as the human pathogenic potential of this species remains unknown.

Purpose: We aimed to assess the utilization of Genotype Resistance Testing (GRT) by Infectious Diseases Units across Italy.

Methods: A cross-sectional study was conducted involving a questionnaire distributed to the Infectious Diseases Unit in Italy. A web-based survey using Google Forms software was utilized and spread via email or cellphone.

Results: Responses were obtained from 101 Infectious Diseases Units. Among these centers, only seven (6.9%) reported not performing GRT at any time. Of the 94 centers performing GRT, 52 (55.3%) sent blood samples to external laboratories. Notably, only 6/35 (17.1%) small centers had internal laboratories, compared to 14/35 (40.0%) medium centers and 22/24 (91.7%) large centers (p<0.001). Most centers requested GRT for treatment-naïve individuals and all cases of virological failure. Only 24 (25.5%) requested GRT of HIVDNA before treatment changes. Regarding virological failure, most centers (38, 40.4%) requested GRT when HIV-RNA levels exceeded 200 copies/mL, while 26 (27.7%) requested it at levels exceeding 50 copies/mL. Additionally, 18 (19.1%) and 12 (12.8%) centers requested GRT at thresholds of 500 copies/mL and 1000 copies/mL, respectively. Regarding the specific GRT test used, 34 (36.2%) were unsure, while 16 (17.0%) reported using both Next-Generation Sequencing (NGS) and Sanger methods. Furthermore, 30 (31.9%) and 14 (14.9%) centers exclusively used NGS and Sanger, respectively. Most centers reported receiving GRT results within one month (n=72, 76.6%), while 22 (23.4%) centers obtained results within two weeks. However, 22 (23.4%) centers typically experienced more than one-month delays. Finally, most participants (86, 91.5%) regarded GRT as a crucial routine test for the treatment of naïve PLWH.

Conclusion: This study demonstrates that most Infectious Diseases Units in Italy continue to consider GRT an essential test for newly diagnosed PLWH in clinical practice. However, the utilization of GRT on HIV-DNA remains limited. Further efforts are required to decrease turnaround time in centers experiencing prolonged delays in obtaining results.

Objectives: Antibacterial-resistant gram-negative hospital-acquired infections result in significant morbidity and mortality. In clinical trials, ceftolozane/tazobactam (C/T) has been effective against these infections; however, real-world findings are limited.

Methods: SPECTRA was a global, retrospective, observational inpatient study of adults treated with C/T for ≥48 hours, conducted between 2016 and 2020. The primary objective was to describe real-world utilisation of C/T: socio-demographic, clinical characteristics, prescribing patterns, clinical outcomes, and healthcare resource utilisation in hospitalized patients treated with C/T.

Results: In total, 617 patients from 7 countries met inclusion criteria. Most (82.7%) had ≥1 comorbidity. The most common medical conditions where C/T was used were pneumonia (29.5%), sepsis (20.4%), complicated intra-abdominal infection (15.1%), and complicated urinary tract infection (14.4%). The most common pathogens were Pseudomonas aeruginosa (87.4%) and Escherichia coli (8.2%). Median C/T treatment duration was 11 days. Clinical success occurred in 67.3% of patients (including those with 'unknown' status in the denominator). In a separate analysis that excluded those with 'unknown' status, clinical success ranged from 94.1% in patients with bacteraemia to 58.9% with sepsis. Overall, 18.8% of patients had documented microbiologic response. All-cause in-hospital mortality was 21.2%; infection-related mortality was 7.6%. Median hospital length of stay was 42 days (30 days for those who received early C/T therapy [before pathogen identification] vs. 48 days for definitive therapy [after identification]).

Conclusions: These data elucidate real-world utilisation and prescribing patterns of C/T in a diverse patient population with complex medical conditions and various profiles of pathogen resistance between 2016 and 2020.