Resistance and Virulence Features in Carbapenem-resistant Acinetobacter baumannii Community Acquired and Nosocomial Isolates in Romania

Abstract

We aimed to identify the virulence and antimicrobial resistance features in Carbapenem Resistant Acinetobacter baumannii (CRAB) strains isolated from hospital settings and compare them with those isolated in the same period of time from community acquired (CA) infections in Bucharest, south of Romania. A total number of 93 A. baumannii strains were isolated in majority from hospitalized patients and from CA infections. The resistance and virulence mechanisms of the strains were characterized by phenotypic and genotypic methods. The antibiotic resistance profiles in H and CA A. baumannii isolates revealed high percentages of carbapenem-resistance in both H and CA isolates. The ciprofloxacin resistance was found very closed in both types of isolates (84%/83.33%). CRAB H and CA isolates revealed the intrinsec carbapenemase OXA-51and the acquired carbapenemases OXA-23, OXA-24, IMP,and VIM-2. The blaOXA-23 gene was identified in different plasmid types (GR2-Aci1, GR6-pACICU2). rep135040, p3S18 and Aci6 in H A. baumannii isolates. The most frequently expressed virulence factor was lipase and DN-ase. OXA-51-like alleles corresponding to the two main sequence groups were identified as blaOXA66 (63.63% of the isolates) and respectively, blaOXA-69 (38.39%) and revealed the corresponding type of ompAand csuE sequence grouping. AphA6 (24%/16.6%), AphA1 (16%/16.6%) and aadB (9.3%/5.5%) genes were responsible for aminoglycosides resistance. Our survey revealed a high drug resistance in A. baumannii isolates. Different plasmid groups containing CRAB isolates may facilitate the blaOXA23 dissemination.

Snapshot of Phenotypic and Molecular Virulence and Resistance Profiles in Multidrug-Resistant Strains Isolated in a Tertiary Hospital in Romania

“…For A. baumannii, two acquired CHLDs encoding genes were revealed in the analyzed strains: bla OXA-23 and bla OXA-24 . The same results were found by Gheorghe et al (2019) in their study [32]. Most of the strains of P. aeruginosa were positive for bla IMP (Supplementary Figure S4) and bla VIM (Supplementary Figure S5).…”

“…Another pathogen that is also an important biofilm producer is A. baumannii [57], an opportunistic pathogen with major implications in HAIs, responsible for outbreaks and severe infections especially in patients with different immunodeficiencies. Although poor in the production of soluble VF (in our study, almost all of the strains produced only one VF-ompA) (see Supplementary Figure S15), it proved to be an important nosocomial pathogen due to the formation of biofilms (especially on medical devices) and due to its MDR, XDR, or PDR phenotypes [30,32,58,59]. Compared with the soluble VF reported for other Gram-negative bacteria, a small number of these factors have been identified for A. baumannii, in comparison with K. pneumoniae and P. aeruginosa.…”

Temporo-spatial variations in resistance determinants and clonality of Acinetobacter baumannii and Pseudomonas aeruginosa strains from Romanian hospitals and wastewaters

“…The strains were screened for CP ( bla VIM , bla IMP , bla NDM , bla KPC for Pa ), and bla OXA-51/69-like , bla OXA-23-like , bla OXA-24-like , bla OXA-58-like , bla OXA-143 , bla OXA-235, bla NDM genes in the case of Ab strains) and ESBL encoding genes ( bla CTX-M , bla TEM , bla SHV , bla PER , bla VEB , bla GES for strains belonging to both species) using previously described primers and PCR protocols [ 27 , 28 ].…”

“…In Romania, in contrast to clinical studies [27,28,[47][48][49][50][51][52][53][54][55][56][57][58][59][60][61], there is little information available on the epidemiology of AMR reservoirs in the environment, especially in polluted water and rivers. We have previously shown that MDR, CP and ESBL-producing K. pneumoniae isolated from clinics, hospital wastewater and urban WWTPs from different regions of the country exhibit multiple antibiotic and antiseptic resistance, as well as virulence genes, with the ST101 clone being the most frequently encountered in all sampling sites [62].…”

Phenotypic and Genotypic Characterization of Recently Isolated Multidrug-Resistant Acinetobacter baumannii Clinical and Aquatic Strains and Demonstration of Silver Nanoparticle Potency

“…Simplex and multiplex PCR were used to screen the presence of carbapenem-and cephalosporin-encoding genes (bla VIM , bla IMP , bla NDM , bla KPC , bla GES , bla SHV , bla TEM , bla CTX-M , bla PER , bla VEB , bla OXA-23 , bla OXA-24 , bla OXA-58 , bla OXA-235 , and bla OXA-51 ), as well as for VM detection (ompA, epsA, csuE, bap, and bfmS) using a DNA template extracted with an alkaline extraction method, specific primers, and amplification programs (Table 1) and checked with gel electrophoresis [28]. Positive strains for the investigated genes were used as the positive controls.…”