First detected OXA-50 carbapenem-resistant clinical isolates Pseudomonas aeruginosa from Bulgaria and interplay between the expression of main efflux pumps, OprD and intrinsic AmpC.
J Med Microbiol
; 68(12): 1723-1731, 2019 Dec.
Article
em En
| MEDLINE
| ID: mdl-31746726
ABSTRACT
Introduction. Carbapenems are often described as the most effective weapon against infections caused by multidrug-resistant bacteria especially those belonging to the group of non-fermenting bacteria such as Pseudomonas. The main mechanisms leading to resistance are the hyperexpression of certain efflux pumps belonging to the resisto-nodular division and the lower expression of the transmembrane porin OprD, sometimes in combination with excessive production of the intrinsic AmpC. Carbapenemases are assumed to play a secondary role.Aim. The aim of this study was to determine the exact mechanisms of carbapenem resistance in Pseudomonas aeruginosa isolates from the largest Bulgarian University hospital 'St. George'- Plovdiv.Methodology. A total of 32 clinical isolates collected from different patients' samples resistant to imipenem and/or meropenem were examined via phenotypic and molecular-genetic tests.Results. No metallo-enzyme production was detected. Three isolates were positive for OXA-50-encoding genes in two of them in combination with other oxacillinases or the bla VEB-1 gene. For the first time, OXA-50-producing P. aeruginosa have been reported in Bulgaria. The increased expression or hyperexpression of MexXY-OprM efflux pump was observed as the main mechanism of resistance. In most cases, it was combined with lower expression or lack of OprD with or without MexAB-OprM hyperexpression. No excessive production of AmpC was detected in comparison to the reference ATCC 27853 P. aeruginosa strain.Conclusion. The increased expression or overexpression of MexXY-OprM efflux pumps is the leading cause of carbapenem resistance in our isolates Pseudomonas, detected in 94â% of the bacteria investigated.
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01-internacional
Base de dados:
MEDLINE
Assunto principal:
Pseudomonas aeruginosa
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Proteínas de Bactérias
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Beta-Lactamases
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Carbapenêmicos
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Porinas
Limite:
Humans
Idioma:
En
Revista:
J Med Microbiol
Ano de publicação:
2019
Tipo de documento:
Article
País de afiliação:
Bulgária