Papers by Gabriel Gutkind
International Journal of Antimicrobial Agents, 2004
International Journal of Antimicrobial Agents, 2010
Diagn Microbiol Infect Dis, 2010
Journal of clinical microbiology, 2010
Journal of clinical microbiology, 2010
En este documento se dan a conocer una serie de recomendaciones para el ensayo, la lectura, la in... more En este documento se dan a conocer una serie de recomendaciones para el ensayo, la lectura, la interpretación y el informe de las pruebas de sensibilidad a los antimicrobianos para los bacilos gram negativos no fermentadores (BGNNF) que se aíslan en humanos. Se adoptaron como base las recomendaciones internacionales, las de la Subcomisión de Antimicrobianos de la Sociedad Argentina de Bacteriología, Micología y Parasitología Clínicas y las de un grupo de expertos invitados. Se incluye, además, la nomenclatura actualizada de los BGNNF y la descripción de algunas de sus características individuales, de sus resistencias naturales o habituales a los antimicrobianos de uso clínico y de los mecanismos responsables de tales resistencias. También se indican los agentes antimicrobianos que se deberían ensayar frente a las distintas especies, con la especificación de cuáles deberían ser informados, y su ubicación estratégica en las placas de cultivo para poder detectar los mecanismos de resis...
Antimicrobial Agents and Chemotherapy, 2021
Changes in Kluyvera taxonomy may clarify each species contribution for recruitment and disseminat... more Changes in Kluyvera taxonomy may clarify each species contribution for recruitment and dissemination of their relevant β-lactamases. The CTX-M-2 subgroup is linked to Kluyvera ascorbata , KLUC to Kluyvera cryocrescens , and CTX-M-25 to Kluyvera georgiana .
Series of 1,3-dibenzyl-1H-4,5,6,7-tetrahydro-1,3-diazepinium and 1,4,5,6,7,8-hexahydro-1,3-diazoc... more Series of 1,3-dibenzyl-1H-4,5,6,7-tetrahydro-1,3-diazepinium and 1,4,5,6,7,8-hexahydro-1,3-diazocinium salts derivatives were efficiently synthesized in excellent yields by dehydrogenation of the corresponding N,N'-dibenzyl aminals employing N-bromosuccinimide (NBS) as dehydrogenating agent under ultrasound irradiation. The present methodology has proven to be simple, efficient and environmentally benign. All novel compounds were identified and characterized by 1H and 13C NMR spectra. The synthesized compounds were screened for their antimicrobial activities.
Microbial Drug Resistance, 2021
The increasing prevalence and dissemination of carbapenemase-producing Enterobacterales represent... more The increasing prevalence and dissemination of carbapenemase-producing Enterobacterales represent a serious concern for public health. We studied the genetic features of a multidrug-resistant isolate of high-risk clone ST147 Klebsiella pneumoniae coharboring mcr-1 and blaNDM-1 recovered from a human clinical urine sample in 2017 in Peru. Whole-genome sequencing and conjugation assays identified mcr-1 and blaNDM-1 genes on two different conjugative plasmids, which belong to IncI2 and IncFIB/HI1B incompatibility groups, respectively. The presence of blaCTX-M-15 (in the studied isolate, located on the chromosome) and mutations in GyrA S83I and ParC S80I were detected, as expected for ST147. In addition, other β-lactamases (blaTEM-26 and blaOXA-1) and PMQR (qnrE2 and aac(6')-Ib-cr) among several resistance determinants were identified. The coexistence not previously described of these genes in the same high-risk clone is a cause for serious concern that supports the need for implementation of genomic surveillance studies.
Microorganisms, 2018
The aim of this study was to investigate the presence of class 1 integrons in a collection of Shi... more The aim of this study was to investigate the presence of class 1 integrons in a collection of Shiga toxin-producing Escherichia coli (STEC) from different origins and to characterize pheno- and genotypically the antimicrobial resistance associated to them. A collection of 649 isolates were screened for the class 1 integrase gene (intI1) by Polymerase chain reaction The variable region of class 1 integrons was amplified and sequenced. Positive strains were evaluated for the presence of antimicrobial resistance genes with microarray and for antimicrobial susceptibility by the disk diffusion method. Seven out of 649 STEC strains some to serogroups, O26, O103 and O130 isolated from cattle, chicken burger, farm environment and pigs were identified as positive for intl1. Different arrangements of gene cassettes were detected in the variable region of class 1 integron: dfrA16, aadA23 and dfrA1-aadA1. In almost all strains, phenotypic resistance to streptomycin, tetracycline, trimethoprim/s...
Journal of Clinical Microbiology, 2019
The aim of this work was to evaluate an easy to perform assay based upon inhibition of MCR activi... more The aim of this work was to evaluate an easy to perform assay based upon inhibition of MCR activity by ethylenediaminetetraacetic acid (EDTA). We included 92 non-related isolates of Enterobacteriaceae (74 E. coli, 17 K. pneumoniae and one S. marcescens). Our proposed method is based on a modification of the Colistin Agar-Spot screening test (CAST), a plate containing 3 μg/mL colistin, by adding an extra plate of Colistin Agar-Spot supplemented with EDTA (eCAST). Bacterial growth was evaluated after 24 h of incubation at 35°C. All the colistin-resistant isolates showed development on the CAST plates. Colistin-resistant K. pneumoniae without mcr-1 and S. marcescens could also grow on the eCAST plates. In contrast, colistin-resistant MCR-producing E. coli were not able to grow in eCAST plates. The combined CAST/eCAST test could provide a simple and easy-to-perform method to differentiate MCR-producing Enterobacteriaceae from those in which colistin-resistance is mediated by chromosomal...
Antimicrobial Agents and Chemotherapy, 2018
ABSTRACTTheblaPER-2-harboring plasmid pCf587 (191,541 bp) belongs to lineage IncA/C1and is closel... more ABSTRACTTheblaPER-2-harboring plasmid pCf587 (191,541 bp) belongs to lineage IncA/C1and is closely related to pRA1. It contains a large resistance island including theblaPER-2gene between two copies of ISKox2-like elements, the toxin-antitoxin modulepemK-pemI, several other resistance genes inserted within a Tn2transposon, a Tn21-like structure, and a class 1 integron. pCf587 belongs to sequence type 13 (ST13), a new plasmid multilocus sequence typing (pMLST) ST.
Journal of Microbiological Methods, 2019
The Journal of antimicrobial chemotherapy, Jan 7, 2018
Journal of global antimicrobial resistance, Jan 9, 2018
The aim of this study was to characterise OXA-258 variants and other features that may contribute... more The aim of this study was to characterise OXA-258 variants and other features that may contribute to carbapenem resistance in Achromobacter ruhlandii. Kinetic parameters for purified OXA-258a and OXA-258b were determined measuring the rate of hydrolysis of a representative group of antimicrobial agents. Whole-genome shotgun sequencing was performed on A. ruhlandii 38 (producing OXA-258a) and A. ruhlandii 319 (producing OXA-258b), and in silico analysis of antimicrobial resistance determinants was conducted. Substrates of the AxyABM efflux pump were investigated by inhibition assays using phenylalanine-arginine β-naphthylamide (PAβN). Outer membrane protein profiles were resolved by 12% sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Kinetic measurements of purified OXA-258 variants displayed an overall weak catalytic efficiency toward β-lactams. A detectable hydrolysis of imipenem was observed. In silico genomic analysis confirmed the presence of 32 and 35 puta...
Frontiers in microbiology, 2018
The use of antimicrobial growth promoters (AGPs) in sub-therapeutic doses for long periods promot... more The use of antimicrobial growth promoters (AGPs) in sub-therapeutic doses for long periods promotes the selection of resistant microorganisms and the subsequent risk of spreading this resistance to the human population and the environment. Global concern about antimicrobial resistance development and transference of resistance genes from animal to human has been rising. The goal of our research was to evaluate the susceptibility pattern to different classes of antimicrobials of colistin-resistant from poultry production systems that use AGPs, and characterize the resistance determinants associated to transferable platforms. strains ( = 41) were obtained from fecal samples collected from typical Argentine commercial broiler farms and susceptibility for 23 antimicrobials, relevant for human or veterinary medicine, was determined. Isolates were tested by PCR for the presence of , extended spectrum β-lactamase encoding genes and plasmid-mediated quinolone resistance (PMQR) coding genes....
Anaerobe, 2017
CfiA (CcrA) metallo-β-lactamase is the main carbapenem resistance mechanism in B. fragilis. From ... more CfiA (CcrA) metallo-β-lactamase is the main carbapenem resistance mechanism in B. fragilis. From cfiA positive isolates detected in a previous surveillance study, 3 displayed resistance to imipenem while the remaining were susceptible. The aim of this study was to identify the cfiA alleles and to analyze the presence of IS elements in their upstream regions. CfiA-1, CfiA-4, CfiA-13, CfiA-19 and CfiA-22 were detected. IS elements belonging to IS21 family and IS942 group were identified upstream to cfiA in the 3 imipenem resistant isolates. We present an exhaustive analysis of cfiA/CfiA registers in databases, illustrating the inconsistencies in both organization and nomenclature. According to this analysis CfiA family comprises nowadays 15 different CfiA variants coded by 24 cfiA sequences. Curation of CfiA database is mandatory, if not new cfiA admission at GenBank will contribute to make this classification more complex.
Antimicrobial agents and chemotherapy, 2018
Ten IMP-8-producing isolates were recovered from surveillance cultures of a neonatal intensive ca... more Ten IMP-8-producing isolates were recovered from surveillance cultures of a neonatal intensive care unit; eight of the isolates were clonally related. A 168.2-kb plasmid was fully sequenced, and it corresponded to the recently described IncA/C1-ST13 plasmid. This plasmid was detected in all isolates, even in those that were not clonally related. One unrelated isolate was also resistant to colistin and positive for This marker was located in a 62.7-kb IncI2 plasmid, which was also fully sequenced.
Antimicrobial agents and chemotherapy, Jan 4, 2018
A putative gene in 14751 showed 99% nucleotide identity with plasmid-encoded Due to a single-nucl... more A putative gene in 14751 showed 99% nucleotide identity with plasmid-encoded Due to a single-nucleotide insertion translating to a truncated protein, 14751 does not confer fosfomycin resistance. Nonetheless, analysis of another genome deposit ( WCH1410) that could be recategorized as after phylogenetic analysis, revealed a 100% identical to the plasmid-borne Collectively, we suggest that represents the most probable origin of .
Antimicrobial agents and chemotherapy, Jan 9, 2018
The natural diversification of CTX-M β-lactamases led to the emergence of Asp240Gly variants in t... more The natural diversification of CTX-M β-lactamases led to the emergence of Asp240Gly variants in the clinic that confer reduced susceptibility to ceftazidime (CAZ). In this study, we compared the impact of this substitution on CAZ and ceftazidime/avibactam (CZA) MICs against isogenic strains with different porin deficiencies. Our results show a noticeable increase in CAZ resistance in clones expressing Asp240Gly-harboring CTX-M when combined with OmpF porin deficiency. Kinetic analysis revealed that the / for CAZ was 5-15-fold higher for all Asp240Gly variants, but remained 200-725-fold lower than that for cefotaxime (CTX). selection of CAZ resistant clones yielded non-susceptible CTX-M-producers (MIC>16 μg/ml) only after overnight incubation; the addition of avibactam (AVI) decreased MICs to a susceptible range against these variants. In contrast, the use of CZA as a selective agent did not yield resistant clones. AVI inactivated both CTX-M-12 and CTX-M-96 with comparable to SHV-...
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Papers by Gabriel Gutkind