Universidad del Desarrollo

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Ceftazidime/avibactam resistance is associated with PER-3-producing ST309 lineage in Chilean clinical isolates of non-carbapenemase producing Pseudomonas aeruginosa
(2024)
Katherine D. Soto
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ALCALDE RICO, MANUEL
;
UGALDE, JUAN ANTONIO
;
Jorge Olivares Pacheco
;
Valeria Quiroz
<jats:sec><jats:title>Introduction</jats:title><jats:p>Ceftazidime/avibactam (CZA) is indicated against multidrug-resistant <jats:italic>Pseudomonas aeruginosa</jats:italic>, particularly those that are carbapenem resistant. CZA resistance in <jats:italic>P. aeruginosa</jats:italic> producing PER, a class A extended-spectrum β-lactamase, has been well documented <jats:italic>in vitro</jats:italic>. However, data regarding clinical isolates are scarce. Our aim was to analyze the contribution of PER to CZA resistance in non-carbapenemase-producing <jats:italic>P. aeruginosa</jats:italic> clinical isolates that were ceftazidime and/or carbapenem non-susceptible.</jats:p></jats:sec><jats:sec><jats:title>Methods</jats:title><jats:p>Antimicrobial susceptibility was determined through agar dilution and broth microdilution, while <jats:italic>bla</jats:italic><jats:sub>PER</jats:sub> 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 <jats:italic>bla</jats:italic><jats:sub>PER-3</jats:sub> gene was induced in a PER-positive isolate by successive passages at 43°C without antibiotics. </jats:p></jats:sec><jats:sec><jats:title>Results</jats:title><jats:p>Twenty-six of 287 isolates studied (9.1%) were CZA-resistant. Thirteen of 26 CZA-resistant isolates (50%) carried <jats:italic>bla</jats:italic><jats:sub>PER</jats:sub>. One isolate carried <jats:italic>bla</jats:italic><jats:sub>PER</jats:sub> 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 <jats:italic>bla</jats:italic><jats:sub>PER-3</jats:sub> 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 β-lactamases and the mutational resistome showed that all isolates had one major alteration in at least one of the genes analyzed. Loss of <jats:italic>bla</jats:italic><jats:sub>PER-3</jats:sub> gene restored susceptibility to CZA, ceftolozane/tazobactam and other β-lactamsin the <jats:italic>in vitro</jats:italic> evolved isolate. </jats:p></jats:sec><jats:sec><jats:title>Discussion</jats:title><jats:p>PER-3-producing ST309 <jats:italic>P. aeruginosa</jats:italic> is a successful multidrug-resistant clone with <jats:italic>bla<jats:sub>PER-3</jats:sub></jats:italic> gene implicated in resistance to CZA and other β-lactams.</jats:p></jats:sec>
Scopus© Citations 1 4
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A multispecies outbreak of carbapenem-resistant bacteria harboring the blaKPC gene in a non-classical transposon element
(2021)
Aniela Wozniak
;
Cristian Figueroa
;
Francisco Moya-Flores
;
Piero Guggiana
;
Claudia Castillo
<jats:title>Abstract</jats:title><jats:sec> <jats:title>Background</jats:title> <jats:p><jats:italic>Klebsiella pneumoniae</jats:italic> is the most frequent KPC-producing bacteria. The <jats:italic>bla</jats:italic><jats:sub>KPC</jats:sub> gene is frequently embedded in Tn4401 transposon, and less frequently in non-Tn4401 elements (NTE<jats:sub>KPC</jats:sub>) variants I-III. The first case of KPC in the UC-CHRISTUS Clinical Hospital was detected in <jats:italic>Pseudomonas aeruginosa</jats:italic>. Soon after this event, KPC was detected in 2 additional <jats:italic>Pseudomonas aeruginosa</jats:italic>, 3 <jats:italic>Escherichia coli</jats:italic>, 3 <jats:italic>Enterobacter cloacae</jats:italic>, 3 <jats:italic>Klebsiella pneumoniae,</jats:italic> and 1 <jats:italic>Citrobacter freundii</jats:italic>, isolated from 6 different patients. We aimed to elucidate the possible mechanisms of genetic transfer and dissemination of the <jats:italic>bla</jats:italic><jats:sub>KPC</jats:sub> gene among isolates of this multispecies outbreak. A molecular epidemiology analysis of the above mentioned clinical isolates (<jats:italic>n</jats:italic> = 13) through Multi-Locus Sequence Typing, plasmid analysis, Pulsed-Field Gel-Electrophoresis, and Whole-genome sequencing (WGS) was performed.</jats:p> </jats:sec><jats:sec> <jats:title>Results</jats:title> <jats:p>High-risk sequence types were found: <jats:italic>K. pneumoniae</jats:italic> ST11, <jats:italic>P. aeruginosa</jats:italic> ST654, and <jats:italic>E. cloacae</jats:italic> ST114. All enterobacterial isolates were not clonal except for 3 <jats:italic>E. coli</jats:italic> isolated from the same patient. WGS analysis in 6 enterobacterial isolates showed that 4 of them had <jats:italic>bla</jats:italic><jats:sub>KPC</jats:sub> embedded in a novel variant of NTE<jats:sub>KPC</jats:sub> designated NTE<jats:sub>KPC</jats:sub>-IIe. Upstream of <jats:italic>bla</jats:italic><jats:sub>KPC</jats:sub> gene there was a 570 pb truncated <jats:italic>bla</jats:italic><jats:sub>TEM-1</jats:sub> gene followed by an insertion sequence that was 84% similar to ISEc63, a 4473 bp element of the Tn3 family. Downstream the <jats:italic>bla</jats:italic><jats:sub>KPC</jats:sub> gene there was a truncated ISKpn6 gene, and the inverted repeat right sequence of Tn4401. The ISec63-like element together with the <jats:italic>bla</jats:italic><jats:sub>KPC</jats:sub> gene plus Tn4401 remnants were inserted in the Tra operon involved in conjugative transfer of the plasmid. This NTE was carried in a broad host-range IncN plasmid. <jats:italic>P. aeruginosa</jats:italic> isolates carried <jats:italic>bla</jats:italic><jats:sub>KPC</jats:sub> gene embedded in a typical Tn4401b transposon in a different plasmid, suggesting that there was no plasmid transfer between <jats:italic>Enterobacteriaceae</jats:italic> and <jats:italic>P. aeruginosa</jats:italic> as initially hypothesized.</jats:p> </jats:sec><jats:sec> <jats:title>Conclusions</jats:title> <jats:p>Most enterobacterial isolates had <jats:italic>bla</jats:italic><jats:sub>KPC</jats:sub> embedded in the same NTE<jats:sub>KPC</jats:sub>-IIe element, suggesting that this multispecies KPC outbreak was due to horizontal gene transfer rather than clonal spread. This poses a greater challenge to infection control measures often directed against containment of clonal spread.</jats:p> </jats:sec>
Scopus© Citations 21 3
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Real-World Performance of Susceptibility Testing for Ceftolozane/Tazobactam against Non-Carbapenemase-Producing Carbapenem-Resistant Pseudomonas aeruginosa
(2022)
RIVAS JIMENEZ, LINA MARIA
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Manuel Alcalde-Rico
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José R. W. Martínez
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María Victoria Moreno
;
Pamela Rojas
<jats:p> Ceftolozane/tazbactam (C/T) is a potent anti-pseudomonal agent that has clinical utility against infections caused by non-carbapenemase, producing-carbapenem-resistant <jats:named-content content-type="genus-species">Pseudomonas aeruginosa</jats:named-content> (non-CP-CR-PA). Accurate, precise, and reliable antimicrobial susceptibility testing (AST) is crucial to guide clinical decisions. </jats:p>
19Scopus© Citations 2

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