| Congresso Brasileiro de Microbiologia 2023 | Resumo: 1023-2 | ||||
Resumo:Uropathogenic Escherichia coli (UPEC) is the major cause of urinary tract infection (UTI). Most UPEC isolates belong to pandemic lineages, particularly ST131; however, the reasons for the success of these clones remain unclear. ST131 comprises clades A, B and C, with subclades C1, C1-M27 and the worldwide dominant C2. Subclade C2 accumulates major virulence factors, plasmid mediated quinolone resistance (PMQR) and extended spectrum B-lactamase (ESBL) encoding genes. The combination of these characteristics might enhance dissemination and human colonization by C2 isolates. The aim of this study was to describe several characteristics of ST131 UPEC isolates in search for attributes providing clues for the basis of the emergency of this high-risk clone. Data from successive UPEC isolates obtained from outpatients in Rio de Janeiro in 2019 (n=992) were compared to previous data of isolates from 2015 (n= 499) and 2005 (n=139). The prevalence of pandemic ST131 and its subclones were determined by multiplex PCR. Antimicrobial susceptibility and ESBL production were determined by disk-diffusion test. Genes encoding CTX-M ESBL, virulence and PMQR were determined by multiplex PCR. Sequencing and PCR results were compared between all clades and between C2 and C-non-C2 (C0, C1 and C1-M27). Statistically significant differences were set at p<0.05. The prevalence of ST131 isolates significantly increased from 3% (n=3) in 2005 to 14% (n=137) in 2019. Between 2015 and 2019, there was an increase of subclade C2 from 10% in 2015 (n= 4) to 24% in 2019 (n= 33) (p=0.1). The same was observed for subclade C1-M27, which increased from 5% (n= 2) in 2015 to 7% (n= 9) 2019 (p=0.4). There was a decrease of C1 from 50% (n= 19) in 2015 to 25% (n= 34) in 2019 (p<0.01). Therefore, isolates from 2019 were further characterized. Resistance to ciprofloxacin was 100% among subclade C2 (n= 33) and C1-M27 (n= 9), and 60% (n= 93) among other clades (p <0.001). Likewise, MDR isolates comprised 73% of C2 (n= 24) and 86% of C1-M-27 (n= 8) isolates, and 21% (n= 22) of other isolates (p<0.001). We detected ESBL production in 52% (n= 17) of subclade C2, 78% (n= 7) of C1-M27 isolates, and 7% (n= 7) of other clades (p<0.001). The predominant ESBL encoding genes were blaCTX-M-15 (58%, n= 18) and blaCTX-M-27 (23%, n= 7). About 41% (n=55) of isolates carried PMQR; the predominant gene was aac(6’)lb-cr, encoded by 56% (n=31) of these isolates. Almost all (n=29, 94%) of the 31 aac(6’)lb-cr encoding isolates were C2. The most frequent virulence genes in ST131 were fyuA (96%, n= 130), followed by iutA (83%, n= 112), pathogenic island MalX (81%, n= 110), traT (72%, n= 97) and kpsMTII (71%, n= 96). Analysis stratified by clades showed that virulence genes kps MTII (91%, n= 30), papA (49%, n= 16), afa/Dr (46%, n= 15), papGII and hlyA (36%, n= 12), and cnf1 (33%, n= 11) were more frequent in subclade C2 when compared with subclades C-non-C2 (p>0.05). Taken together, we show that C2 isolates carry several virulence and resistance features different than other ST131 clades. The most prominent differences were increased ciprofloxacin resistance, ESBL production, carriage of aac(6’)-Ib-cr, invasins (kpsMTII), adhesins (papA, afa/Dr, papGII) and toxins (hlyA, cnf1) encoding genes. The contribution of each of these features in colonization, UTI and to the success of ST131 in Rio de Janeiro deserves further studies. Palavras-chave: Antimicrobial resistance, ESBL, Escherichia coli ST131, Urinary tract infection, Virulence Agência de fomento:CNPq, CAPES, FAPERJ, INPRA | |||||