Epidemiology and antibiotic resistance trends in clinical isolates of Pseudomonas aeruginosa from Rio de janeiro - Brazil: Importance of mutational mechanisms over the years (1995–2015)

High prevalence of atypical virulotype and genetically diverse background among Pseudomonas aeruginosa isolates from a referral hospital in the Brazilian Amazon

“…Moreover, 40.7% of tested isolates were classified as MDR or XDR, which were significantly predominant in the AICU ( P = 0.0003) ( Table 3 ) and associated to genetically related clonal groups ( P = 0.0141) ( Table 6 ). For instance, our findings agree with recent data reported by Santos et al [ 20 ], which also showed an increasing trend on resistance to carbapenems, aminoglycosides and fluoroquinolones associated to spread of P . aeruginosa MDR/XDR strains over 21 years’ period in Rio de Janeiro, Brazil.…”

“…A reduced number of transmissible resistance markers were detected among tested isolates, with bla CTX-M1 (20.4%– 11/54) as the most frequent, followed by bla SPM-1 (5/54–9.2%), bla OXA-2 (3/54–5.5%) and bla OXA-10 (3/54–5.5%). Our data demonstrate the predomination and wide spread of SPM-1 MDR/XDR strains in Brazilian hospitals and with the increasing transmission trend of ESBLs CTX-M and OXA variants genes worldwide, as previously reported [ 20 , 23 , 45 , 76 , 81 , 82 ]. Finally, our results highlight the impact of horizontally acquired resistance mechanisms, mainly ESBLs and class B MBL, in the increasing resistance rates and its commonly association to MDR/XDR P .…”

“…Two of nine isolates comprised clonal group H/ST244, where bla CTX-M1 was shared by both isolates and two comprised clonal group G/ST244; the other five isolates were genetically unrelated and three harbored bla CTX-M1 gene (Fig 2). Endemic clone in Brazil, ST277 is frequently associated to MDR/XDR isolates and dissemination of bla SPM-1 gene [20,23,92]. Interestingly, isolates comprising clonal group A/ST277 shared bla SPM-1 , but harbored distinct bla OXA genes; one isolate of clonal group B/ST277 harbored both bla SPM-1 and bla OXA-10 genes, while the other harbored only bla OXA-10 gene; isolates comprising clonal group C/ST277 shared bla SPM-1 , but only one isolate harbored bla OXA-2 (Fig 2).…”

“…The increasing trend of resistance to anti-pseudomonal antibiotics, especially carbapenems, aminoglycosides and fluoroquinolones has contributed to the emergence of P. aeruginosa MDR/XDR strains, posing a challenge to infection treatment [20][21][22]. Among the several resistance mechanisms in P. aeruginosa, the role of transferable resistance determinants is overwhelming, particularly those encoding classes A and D extended-spectrum β-lactamases (ESBLs) and class B metallo-β-lactamases (MBLs) [23][24][25][26].…”

“…The increasing trend of resistance to anti-pseudomonal antibiotics, especially carbapenems, aminoglycosides and fluoroquinolones has contributed to the emergence of P . aeruginosa MDR/XDR strains, posing a challenge to infection treatment [ 20 – 22 ]. Among the several resistance mechanisms in P .…”