Resistance markers and virulence factors in carbapenem-resistant Pseudomonas aeruginosa recovered in a prospective study in Argentina.

ELENA ALAN; CEJAS DANIELA; GUTKIND GABRIEL; DI CONZA JOSÉ; RADICE MARCELA

San Francisco

Congreso; ASM MICROBE 2019; 2019

ASM

P. aeruginosa (PA) possesses numerous antimicrobial resistance mechanisms and virulence factors which contributes to its success as an opportunistic pathogen. A prospective study was performed including 15 centers from Argentina (May-July 2018) aimed to determine carbapenem resistance, detect acquired carbapenemases and to investigate the presence of mcr-1 and PMQR. Also, the purpose was to evaluate the presence of diverse virulence factors and to assess the correlation among virulence and resistance levels.Antipseudomonal agents MIC was assessed according to CLSI. Carbapenem resistant PA (CR-PA) were categorised into multi-drug (MDR), extensively (XDR) and pandrug resistant (PDR) according to Magiorakos et al. Presence of carbapenemase coding genes was evaluated by multiplex PCR as described Poirel et al.-2011. PMQR coding genes and mcr-1 were detected by simplex PCR and sequencing.Phenotypic motility (swimming, twitching, swarming) was determined according to Kornberg et al. and O?Toole et al. Biofilm formation was analyzed as proposed by O?Toole et al. and Stepanovic et al. Pyocyanin pigment was quantified according to Crawford et al. Relationship between resistance and virulence was analyzed with Kruskall ? Wallis test and Dunn?s test for different medians.In this study, 438 PA were recovered, being 16% (69) carbapenem resistants. Four CR-PA were classified as PDR, 32 as XDR and 21 as MDR. Three CR-PA harboured blaVIM-2 and 4, blaVIM-11. Four VIM-producing PA were positive for qnrD, while 1 non-VIM producing CR-PA was positive for qnrD and another for qnrS. Not a single CR-PA was positive for mcr-1.No significant differences were observed when analysing motility modes (swimming, twitching and swarming) or pyocyanin production among MDR, XDR and PDR PA. Twenty-two, 35 and 6 CR-PA were weak, moderate and strong biofilm producers, respectively. Biofilm formation was significantly higher in those MDR with respect to XDR isolates.Conclusion: The carbapenem resistance rate among PA is in accordance with previous national data. blaVIM-11 was the predominant allele and remained yet as a secondary cause of carbapenem resistance in PA. This is the first report of blaVIM and qnrD association in PA. Despite previous reports, we have not recognised any correlation between resistance levels and the in vitro expression virulence factors.