Carbapenem-resistant and cephalosporin-susceptible: a worrisome phenotype among Pseudomonas aeruginosa clinical isolates in Brazil
Braz. j. infect. dis
;
21(1): 57-62, Jan.-Feb. 2017. tab, graf
Article
in English
| LILACS
| ID: biblio-839184
ABSTRACT
Abstract The mechanisms involved in the uncommon resistance phenotype, carbapenem resistance and broad-spectrum cephalosporin susceptibility, were investigated in 25 Pseudomonas aeruginosa clinical isolates that exhibited this phenotype, which were recovered from three different hospitals located in São Paulo, Brazil. The antimicrobial susceptibility profile was determined by CLSI broth microdilution. β-lactamase-encoding genes were investigated by PCR followed by DNA sequencing. Carbapenem hydrolysis activity was investigated by spectrophotometer and MALDI-TOF assays. The mRNA transcription level of oprD was assessed by qRT-PCR and the outer membrane proteins profile was evaluated by SDS-PAGE. Genetic relationship among P. aeruginosa isolates was assessed by PFGE. Carbapenems hydrolysis was not detected by carbapenemase assay in the carbapenem-resistant and cephalosporin-susceptible P. aueruginosa clinical isolates. OprD decreased expression was observed in all P. aeruginosa isolates by qRT-PCR. The outer membrane protein profile by SDS-PAGE suggested a change in the expression of the 46 kDa porin that could correspond to OprD porin. The isolates were clustered into 17 genotypes without predominance of a specific PFGE pattern. These results emphasize the involvement of multiple chromosomal mechanisms in carbapenem-resistance among clinical isolates of P. aeruginosa, alert for adaptation of P. aeruginosa clinical isolates under antimicrobial selective pressure and make aware of the emergence of an uncommon phenotype among P. aeruginosa clinical isolates.
Full text:
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Index:
LILACS (Americas)
Main subject:
Pseudomonas aeruginosa
/
Carbapenems
/
Cephalosporins
/
Beta-Lactam Resistance
/
Anti-Bacterial Agents
Limits:
Humans
Country/Region as subject:
South America
/
Brazil
Language:
English
Journal:
Braz. j. infect. dis
Journal subject:
Communicable Diseases
Year:
2017
Type:
Article
Affiliation country:
Brazil
Institution/Affiliation country:
Universidade Federal de São Paulo/BR
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