Improved Blue Carba test and Carba NP test for detection and classification of major Class A and B carbapenemases, including dual producers, among Gram-negative bacilli.

Unlabelled: Prompt and precise identification of carbapenemase-producing organisms is crucial for guiding clinical antibiotic treatments and limiting transmission. Here, we propose modifying the Blue Carba test (BCT) and Carba NP-direct (CNPd) to identify molecular carbapenemase classes, including dual carbapenemase strains, by adding specific Class A and Class B inhibitors. We tested 171 carbapenemase-producing Gram-negative bacilli strains-21 in Class A (KPC, NMC, SME), 58 in Class B (IMP, VIM, NDM, SPM), and 92 with dual carbapenemase production (KPC+NDM, KPC+IMP, KPC+VIM), all previously positive with BCT or CNPd.

Emergence of optrA-mediated linezolid resistance in clinical isolates of Enterococcus faecalis from Argentina.

Objectives: The aim of this study was to characterize the first 14 optrA-carrying linezolid resistant E. faecalis clinical isolates recovered in seven Argentinian hospitals between 2016 and 2021. The epidemiology of optrA-carrying isolates and the optrA genetic context were determined.

Novel Metallo-β-Lactamase Isolated from a Clinical Strain Resistant to Colistin.

Objective: We aimed to describe a colistin (COL)-resistant (R) (Cvi) isolate from a septic patient in Argentina expressing a previously unknown gene, .

Methods: In 2019, a 12 year old child was injured with a thorn in a lagoon. The child was hospitalized due to sepsis and multiple abscesses.

Emergence of Hyper-Epidemic Clones of Enterobacterales Clinical Isolates Co-Producing KPC and Metallo-Beta-Lactamases during the COVID-19 Pandemic.

Background: The global spread of carbapenemase-producing Enterobacterales has become an epidemiological risk for healthcare systems by limiting available antimicrobial treatments. The COVID-19 pandemic worsened this scenario, prompting the emergence of extremely resistant microorganisms.

Methods: Between March 2020 and September 2021, the NRL confirmed 82 clinical Enterobacterales isolates harboring a combination of and MBL genes.

Emergence of KPC-31, a KPC-3 Variant Associated with Ceftazidime-Avibactam Resistance, in an Extensively Drug-Resistant ST235 Pseudomonas aeruginosa Clinical Isolate.

A ceftazidime-avibactam-resistant KPC-producing Pseudomonas aeruginosa strain was isolated in Argentina from a tracheal aspirate. The patient was treated with ceftazidime-avibactam in combination with other agents for 130 days. Whole-genome sequencing of P.

Simple Phenotypic Tests To Improve Accuracy in Screening Chromosomal and Plasmid-Mediated Colistin Resistance in Gram-Negative Bacilli.

CLSI and EUCAST recommend that only broth microdilution (BMD) should be used for routine colistin susceptibility testing; however, this technique can be difficult to perform in resource-poor settings. The purpose of this study was to evaluate the accuracy of a colistin agar spot test (COL-AS) and a colistin drop test (COL-DT) compared to BMD. COL-AS and COL-DT were assessed with a collection of 271 Gram-negative bacilli clinical isolates: 195 (including 63 positive strains), 37 spp.

[Evolution of the performance of Latin America Reference Laboratories in the detection of mechanisms of antimicrobial resistanceEvolução do desempenho dos Laboratórios de Referência na América Latina na detecção de mecanismos de resistência antimicrobiana].

Objective: The objective is to present the results of the Latin American Program for Quality Assurance in Bacteriology and Antimicrobial Resistance (LA-EQAS) between 2000 and 2018 and the evolution of the detection of resistance mechanisms with clinical impact.

Methods: The participating National Reference Laboratories (NRLs) received 25 surveys with 10 strains in each one, representing a total of 86 bacterial species and 40 resistance mechanisms. To evaluate the performance of the NRLs, five indicators were analyzed: bacterial identification, interpretation of susceptibility testing, acceptable ranges for zones of inhibition, inferred resistance mechanism, and delay time for the response.

Daptomycin Resistance in Clinical MRSA Strains Is Associated with a High Biological Fitness Cost.

Daptomycin remains as one of the main treatment options for Methicillin-Resistant Staphylococcus aureus (MRSA). Sporadic resistance cases reported in patients treated with either daptomycin or glycopeptides are a growing concern. In a previous study, we described a clinical case of a patient with a community-acquired MRSA infection resistant to daptomycin and with intermediate resistance to vancomycin who developed a recurrent infection with a susceptible isogenic strain.

Characterization of Streptococcus pneumoniae invasive serotype 19A isolates from Argentina (1993-2014).

The aim of this study was to characterize Streptococcus pneumoniae serotype 19A isolates causing invasive pneumococcal disease in children, collected in Argentina between 1993 and 2014. A total of 176 isolates serotype 19A were analyzed. There was an increase in the proportion of serotype 19A isolates from 3% in 1993 to 6% in 2011, prior to the introduction of PCV13 in 2012, and from 2012 to 2014 its proportion gradually decreased.

Molecular characteristics of mcr-1-carrying plasmids and new mcr-1 variant recovered from polyclonal clinical Escherichia coli from Argentina and Canada.

We have characterized nine mcr-1-harboring plasmids from clinical Escherichia coli isolates previously described in Argentina and Canada. Three of these plasmids carried a mcr-1-variant called here mcr-1.5.

Molecular characterization of a clinical Haemophilus parainfluenzae isolate with cefotaxime resistance and decreased susceptibility to fluoroquinolones.

We report an H. parainfluenzae clinical isolate resistant to cefotaxime and with decreased susceptibility to ciprofloxacin recovered from a patient with cystic fibrosis. The isolate had elevated MICs of ampicillin (256mg/L), amoxicillin-clavulanate (8mg/L), cefuroxime (8mg/L) and cefotaxime (4mg/L), and showed a β-lactamase-producing amoxicillin-clavulanic acid-resistant (BLPACR) phenotype.

[First isolation in Argentina of community-acquired methicillin-resistant Staphylococcus aureus with intermediate susceptibility to vancomycin and nonsusceptibility to daptomycin].

Unlabelled: We report the first case in Argentina of community-acquired methicillin-resistant Staphylococcus aureus with intermediate susceptibility to vancomycin and nonsusceptibility to daptomycin.

Case Report: A male patient with a history of chronic renal failure on hemodialysis and hip fracture osteosynthesis was admitted to hospital for persistent febrile syndrome following the displacement of the prosthesis by trauma. Blood cultures grew community-acquired methicillin-resistant Staphylococcus aureus.

[Capability of national reference laboratories in Latin America to detect emerging resistance mechanisms].

Objective: To evaluate the capability of 17 national reference laboratories participating in the Latin American Quality Control Program in Bacteriology and Antibiotic Resistance (LA-EQAS) to detect emerging resistance mechanisms- namely: resistance of enterobacteria to carbapenems due to the presence of Klebsiella pneumoniae carbapenemase (KPC) and metallo-beta-lactamase (MBL) type IMP, and intermediate resistance of Staphylococcus aureus isolates to vancomycin (vancomycin-intermediate resistant S. aureus-VISA).

Methods: The following three isolates were sent to the 17 participating LA-EQAS laboratories: KPC -producing Klebsiella pneumoniae PAHO-161, IMP-producing Enterobacter cloacae PAHO-166, and S.

Molecular epidemiology of vancomycin-resistant Enterococcus faecium in Argentina.

Objective: To characterize the mechanism of glycopeptide resistance and to determine the genetic relatedness among strains by pulsed-field gel electrophoresis (PFGE) in vancomycin-resistant Enterococcus faecium from Argentina.

Materials And Methods: A total of 189 vancomycin-resistant single-patient isolates of Enterococcus faecium recovered between January 1997 and December 2000 from 30 hospitals in Argentina were studied. Minimum inhibitory concentrations were determined by the agar dilution method and van genes were detected by PCR.