Extraintestinal pathogenic Escherichia coli (ExPEC) O-serotype distribution and antibiotic resistance profiles among the aging population in China: A longitudinal, multi-center study.

Extraintestinal pathogenic Escherichia coli (ExPEC) is a leading cause of community-acquired bacteremia and sepsis, which contributes to the substantial burden of invasive E. coli disease (IED) in older adults. This study aimed to estimate the O-serotype distribution of blood and sterile site ExPEC among older adults in China and the characteristics of antimicrobial resistance, O-serotypes, and O genotypes.

Emergence of ceftazidime-avibactam resistance in clinical Klebsiella pneumoniae during therapy.

Background: The emergence of ceftazidime-avibactam resistance in Klebsiella pneumoniae poses a significant public health threat, driven by mutations in the bla . This study investigates the evolution of KPC variants (KPC-33, KPC-84, KPC-190) during therapy, highlighting their impact on resistance profiles and treatment challenges. Understanding these mechanisms is critical for guiding clinical interventions.

Antimicrobial activity of lefamulin against pathogens most commonly causing community-acquired pneumonia: results from the China antimicrobial surveillance network in 2020-2022.

Objectives: Lefamulin is a novel pleuromutilin antibiotic used for the treatment of community-acquired pneumonia (CAP). This study aimed to evaluate the in vitro antimicrobial activity of lefamulin against clinical isolates obtained from China.

Methods: 1,052 non-duplicate isolates included the following isolates: Streptococcus pneumoniae (n = 529), Staphylococcus aureus (n = 306), Haemophilus influenzae (n = 121), Moraxella catarrhalis (n = 81), and Mycoplasma pneumoniae (n = 15), were collected from 70 hospitals participating in the China Antimicrobial Surveillance Network (CHINET) between October 1, 2020, and November 30, 2022.

Characterization of OXA-1224, a novel OXA-213-like β-lactamase encoded by the chromosome of Acinetobacter pittii.

Objectives: This study investigates the transfer mechanism and functional properties of OXA-1224, the novel d-class β-lactase in the clinical isolate Acinetobacter pittii (A. pittii) PT-01.

Methods: Bacterial identification was performed using matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS), and resistance genes were identified via polymerase chain reaction (PCR) and DNA sequencing.

Identification of CMY-190, a novel chromosomally encoded AmpC β-lactamase, and plasmid-encoded KPC-2 in a clinical isolate of .

This study investigates the antibiotic resistance phenotype and genotype of strain YS01, isolated from a peritoneal effusion sample, focusing on both chromosomal and plasmid-mediated resistance mechanisms to inform clinical antibiotic therapy. Our results reveal the presence of the chromosomally encoded β-lactamase CMY-190 and the plasmid-encoded carbapenemase KPC-2, which confer resistance to cephalosporins and carbapenems, respectively. CMY-190 exhibits substrate and inhibition profiles similar to AmpC β-lactamases and shares 88.

Modification of carbapenemase inhibition test and comparison of its performance with NG-Test CARBA 5 for detection of carbapenemase-producing Enterobacterales.

Aims: Adequately and accurately identifying carbapenemase-producing Enterobacterales (CPE) is vital for selecting appropriate antimicrobial therapy and implementing effective infection control measures. This study aims to optimize the phenotypic detection method of carbapenemase for routine diagnostics in clinical microbiology laboratories.

Methods And Results: Carbapenemase genes in 2665 non-duplicate CRE clinical strains collected from various regions of China were confirmed through whole-genome sequencing (WGS).

Prediction of antimicrobial resistance in Klebsiella pneumoniae using genomic and metagenomic next-generation sequencing data.

Objectives: Klebsiella pneumoniae is a significant pathogen with increasing resistance and high mortality rates. Conventional antibiotic susceptibility testing methods are time-consuming. Next-generation sequencing has shown promise for predicting antimicrobial resistance (AMR).

Complex evolutionary trajectories in vivo of two novel KPC variants conferring ceftazidime-avibactam resistance.

More and more ceftazidime-avibactam-resistant KPC-producing Klebsiella pneumoniae have been reported with its widespread use, and the detection rate of KPC variants has increased dramatically. However, the evolutionary mechanism and fitness effects during KPC mutation remained unknown. Here, we report the complex in vivo evolutionary trajectories of two novel KPC variants, KPC-155 (L169P/GT242A) and KPC-185 (D179Y/GT242A), from K.

Dynamic evolution of ceftazidime-avibactam resistance from a single patient through the IncX3_NDM-5 plasmid transfer and bla mutation.

The rapid dissemination of carbapenem-resistant Enterobacterales (CRE) especially carbapenem-resistant Klebsiella pneumoniae (CRKP) poses a great threat to global public health. Ceftazidime-avibactam, a novel β-lactam/β-lactamase inhibitor combination, has been widely used due to its excellent antibacterial activity against KPC-producing K. pneumoniae.

Comparison of three colloidal gold immunoassays and GeneXpert Carba-R for the detection of variants.

The increasing use of ceftazidime-avibactam has led to the emergence of a wide range of ceftazidime-avibactam-resistant variants. Particularly, the conventional carbapenemase phenotypic assay exhibited a high false-negative rate for KPC-2 variants. In this study, three colloidal gold immunoassays, including the Gold Mountainriver CGI test, Dynamiker CGI test and NG-Test CARBA5, and GeneXpert Carba-R, were used to detect the presence of KPC-2 carbapenemase and its various variants in 42 strains.

Molecular mechanisms responsible KPC-135-mediated resistance to ceftazidime-avibactam in ST11-K47 hypervirulent .

Ceftazidime-avibactam resistance attributable to the 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 that harboured the gene. This strain possessed fimbriae and biofilm, demonstrating pathogenicity.

Identification of a novel Providencia species showing multi-drug-resistant in three patients with hospital-acquired infection.

Providencia species are important opportunistic pathogens for humans and are associated with several infectious diseases. In this study, we found three clinical strains belonging to a novel Providencia species, namely Providencia huashanensis, including strains CRE-3FA-0001, CRE-138-0026, and CRE-138-0111. These strains were recovered from three patients, and all of them were associated with nosocomial infections, including incision infection, urinary tract infection, and intracranial infection.

In vitro mimicry of in vivo KPC mutations by ceftazidime-avibactam: phenotypes, mechanisms, genetic structure and kinetics of enzymatic hydrolysis.

Ceftazidime-avibactam (CZA) is employed for the treatment of infections caused by carbapenemase-producing (KPC-KP). Resistance to CZA is frequently linked to point mutations in the . We conducted simulations of mutations using CZA.

Spread and evolution of bla-plasmid between Serratia marcescens and Klebsiella pneumoniae.

Objectives: bla-carrying Enterobacterales have post great challenges to global healthcare systems. In this study, we reported the evolution and spread of bla between Serratia marcescens and Klebsiella pneumoniae.

Methods: Four S.

Global emergence of a hypervirulent carbapenem-resistant Escherichia coli ST410 clone.

Carbapenem-resistant Escherichia coli (CREC) ST410 has recently emerged as a major global health problem. Here, we report a shift in CREC prevalence in Chinese hospitals between 2017 and 2021 with ST410 becoming the most commonly isolated sequence type. Genomic analysis identifies a hypervirulent CREC ST410 clone, B5/H24RxC, which caused two separate outbreaks in a children's hospital.

carbapenemase variants: the new threat to global public health.

carbapenemase (KPC) variants, which refer to the substitution, insertion, or deletion of amino acid sequence compared to wild type, have reduced utility of ceftazidime-avibactam (CZA), a pioneer antimicrobial agent in treating carbapenem-resistant infections. So far, more than 150 variants have been reported worldwide, and most of the new variants were discovered in the past 3 years, which calls for public alarm. The KPC variant protein enhances the affinity to ceftazidime and weakens the affinity to avibactam by changing the KPC structure, thereby mediating bacterial resistance to CZA.

Emergence of KPC-134, a KPC-2 variant associated with ceftazidime-avibactam resistance in a ST11 clinical strain.

The emergence of various new carbapenemase (KPC) variants leading to ceftazidime-avibactam treatment failure is a new challenge in current clinical anti-infection treatment. Here, we report a ceftazidime-avibactam-resistant 1072-2 clinical strain carrying a novel KPC variant, KPC-134, which differs from KPC-2 by both single mutation (D178A) and 8-amino acid insertions (asp-asp-asn-arg-ala-pro-asn-lys). The results of antimicrobial susceptibility testing showed that the isolate was resistant to meropenem (MIC = 4 mg/L), ceftazidime (MIC ≥ 32 mg/L), cefepime (MIC ≥128 mg/L), aztreonam (MIC ≥128 mg/L), and ceftazidime-avibactam (MIC ≥128 mg/L) but sensitive to imipenem (MIC = 0.

Development of Aztreonam Resistance in Meropenem-Resistant Pseudomonas aeruginosa Owing to Overexpression of the .

The rapid acquisition of antibiotic resistance of Pseudomonas aeruginosa has been a complex problem in clinics. Two meropenem-resistant P. aeruginosa isolates were collected from the same patient on May 24, 2021, and June 4, 2021, respectively.

Performance of Ceftazidime-Avibactam 30/20-μg and 10/4-μg Disks for Susceptibility Testing of and Pseudomonas aeruginosa.

Ceftazidime-avibactam, a new β-lactam-β-lactamase inhibitor combination, is active against multidrug-resistant and Pseudomonas aeruginosa isolates and has became available for clinical use in China in the latter half of 2019. In this study, we evaluated the performance of the disk diffusion test with ceftazidime-avibactam 10/4-μg and 30/20-μg disks, compared with the reference broth microdilution method, with a collection of 467 and 182 P. aeruginosa nonduplicate clinical isolates.

Identification of KPC-112 from an ST15 Klebsiella pneumoniae Strain Conferring Resistance to Ceftazidime-Avibactam.

Ceftazidime-avibactam is an effective antibiotic combination of a β-lactam and a β-lactamase inhibitor against Klebsiella pneumoniae-carbapenemase (KPC)-producing . Despite a relatively low resistance rate, reports of resistance to ceftazidime-avibactam mainly caused by the mutations in KPC have increased in recent years. Here, we report a ceftazidime-avibactam-resistant and carbapenem-susceptible Klebsiella pneumoniae strain carrying a novel KPC variant, KPC-112, which differs from KPC-2 by 4-amino-acid deletions at Ambler positions 166L/167E and 242G/243T.

First Report of , , and Carrying Showing High-Level Resistance to Carbapenems.

The prevalence of carbapenem-resistant is increasing. Although carbapenemase production is the main resistance mechanism of to carbapenems, there are still some reports of non-carbapenemase-producing showing high-level resistance to carbapenems. In this study, we had also isolated a carbapenemase-negative carbapenem-resistant L204 from a patient with an asymptomatic urinary tract infection.

Antimicrobial activities of sitafloxacin and comparators against the clinical isolates of less common nonfermenting Gram-negative bacteria.

Objectives: To evaluate in vitro activities of sitafloxacin and comparators against the clinical isolates of less common nonfermenting Gram-negative bacteria (NFGNB).

Methods: The isolates of less common NFGNB were collected during a long period spanning five years from 2016 to 2020 in Huashan Hospital, Fudan University in Shanghai. A broth microdilution method was used to determine the minimum inhibitory concentrations (MICs) of sitafloxacin and comparators.