Investigation of the association of virulence genes and biofilm production with infection and bacterial colonization processes in multidrug-resistant Acinetobacter spp.

Adriana Maria C.M Da Silva,José Luciano B De Farias Filho,Maria Amélia V Maciel,Jailton L.C Lima,Isabella M.F Cavalcanti,Sérgio D Costa Júnior

doi:10.1590/0001-3765202120210245

Adriana Maria C.M Da Silva, José Luciano B De Farias Filho + Show 4 more

Open Access

https://doi.org/10.1590/0001-3765202120210245

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Abstract

The aim of this study was to evaluate the phenotypic and molecular patterns of biofilm formation in infection and colonization isolates of Acinetobacter spp. from patients who were admitted in a public hospital of Recife-PE-Brazil in 2018-2019. For the biofilm phenotypic analysis, Acinetobacter spp. isolates were evaluated by the crystal violet staining method; the search of virulence genes (bap, ompA, epsA, csuE and bfmS) was performed by PCR; and the ERIC-PCR was performed for molecular typing. Amongst the 38 Acinetobacter spp. isolates, 20 were isolated from infections and 18 from colonization. The resistance profile pointed that 86.85% (33/38) of the isolates were multidrug-resistant, being three infection isolates, and two colonization isolates resistant to polymyxin B. All the isolates were able to produce biofilm and they had at least one of the investigated virulence genes on their molecular profile, but the bap gene was found in 100% of them. No clones were detected by ERIC-PCR. There was no correlation between biofilm formation and the resistance profile of the bacteria, neither to the molecular profile of the virulence genes. Thus, the ability of Acinetobacter spp. to form biofilm is probably related to the high frequency of virulence genes.

Highlights

The genus Acinetobacter is constituted by Gram-negative coccobacilli which are strictly anaerobic, immobile, non-fermentative, catalase positive and oxidase negative (Lee et al 2017)
Along with the species Acinetobacter pitti, Acinetobacter nosocomialis, Acinetobacter calcoaceticus, Acinetobacter seifertii and Acinetobacter dijkshoorniae, it constitutes the Acinetobacter calcoaceticus-baumannii (ACB) complex, and it is a pathogen potentially associated to healthcare-associated infections (HAI) (Nemec et al 2015, Vijayakumar et al 2019)
The incidence of HAIs caused by species of the genus Acinetobacter is increasing on the global scenario, and in spite of accounting for over 50 validly named species, Acinetobacter baumannii is the predominant pathogen isolated from patients in hospital environments (Li et al 2016, Wong et al 2017)

Summary

Introduction

The genus Acinetobacter is constituted by Gram-negative coccobacilli which are strictly anaerobic, immobile, non-fermentative, catalase positive and oxidase negative (Lee et al 2017). Amongst the 63 validly named species, Acinetobacter baumannii is the most clinically relevant pathogen. Along with the species Acinetobacter pitti, Acinetobacter nosocomialis, Acinetobacter calcoaceticus, Acinetobacter seifertii and Acinetobacter dijkshoorniae, it constitutes the Acinetobacter calcoaceticus-baumannii (ACB) complex, and it is a pathogen potentially associated to healthcare-associated infections (HAI) (Nemec et al 2015, Vijayakumar et al 2019). Acinetobacter spp. strains, especially Acinetobacter baumannii, are considered a threat to public health in a global scenario mainly due to its tendency of acquiring resistance mechanisms. This feature favors its survival even under the use of selective antimicrobial agents, and disseminates multidrugresistant strains (Reena et al 2017). In Brazil, it was observed that the rate of Acinetobacter spp

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