| Congresso Brasileiro de Microbiologia 2023 | Resumo: 258-1 | ||||
Resumo:Nosocomial infections are often associated with KPC-producing Klebsiella pneumoniae (KPC-Kp). The gastrointestinal tract works as an important reservoir for these strains, and prior colonization is a major risk factor for the development of that life-threatening infections. However, the reasons behind why some patients with similar health statuses and bacterial colonization progress to infection while others do not remain unclear. Thus, we aimed to identify genetic determinants present in KPC-Kp isolates that may contribute to the transition from colonization to infection. A retrospective study from May 2018 to June 2021 selected 374 KPC-Kp isolates from surveillance swabs and clinical infection samples for molecular typing ( XbaI-PFGE). Out of those isolates, 24 were categorized as only colonizers (ONLYCOL) and 27 as colonizers that transited to disease (COLINFEC) according to XbaI-PFGE and similarity among KPC-Kp isolated from surveillance swab and infection sites. That 51 KPC-KP were submitted to antimicrobial susceptibility test, biofilm production essay, and whole-genome sequencing. Antibiotic resistance and biofilm essays showed no significant differences between ONLYCOL and COLINFEC groups. MLST revealed eight sequence types – ST, with clonal complex 258 (ST 11 and 340) being prevalent in both groups; however, ST 16 was associated with the COLINFEC group (p = 0.034). Moreover, K-typing analysis did not show any association with any group, as well as the resistome, the plasmidome, and the virulome results. The blaKPC-2 allele was present in all 51 isolates, and other 48 antimicrobial resistance genes were identified. Several determinants for virulence were assessed in all KPC-KP, including types 1 (fim operon) and 3 (mrk operon) fimbriae, and enterobactin (ent operon) and salmochelin (iro operon) siderophores. In addition, yersiniabactin system and colibactin toxin were also broadly representative in both groups. IncFIB(K) and IncFII(K) were the most common plasmid replicons, but 23 others were also detected. A pangenome analysis identified 2,549 core genes (shared by 99% of the isolates) out of a total of 13,189 gene annotations, and over 6,600 genes categorized as accessory genome (present in less than 15% of the isolates).
The comparative genomic analysis identified seven annotations associated with the COLINFEC group (p < 0,01), including two insertion sequences (IS5 family and ISNCY family), two heat-shock proteins (HtpX and IbpA), the Q anti-termination protein, and two hypothetical proteins. Other annotations associated with the metabolism of metals, salts, and minerals were associated with the ONLYCOL group. In conclusion, this study shed light on the genetic determinants of KPC-Kp isolates and their role in the transition from colonization to infection. Specific genetic factors were associated with the progression to infection, such as the ST 16 sequence type and seven gene annotations. These findings contribute to the understanding of the molecular mechanisms underlying the pathogenicity of KPC-Kp, and may have implications for the development of future targeted interventions to prevent such infections. Further research is warranted to
elucidate additional genetic factors and their interactions, providing valuable insights for infection control strategies in hospital settings. Palavras-chave: Nosocomial infection, carbapenemase-producing Klebsiella pneum, colonization and infection, Whole genome sequencing Agência de fomento:Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES | |||||