| Congresso Brasileiro de Microbiologia 2023 | Resumo: 522-1 | ||||
Resumo:Klebsiella pneumoniae is one of the main pathogens isolated with infections caused by multidrug resistant microorganisms, mainly due to the production of K. pneumoniae carbapenemase (KPC). This enzyme confers resistance to most beta-lactams, however it is inhibited by new beta-lactamase inhibitors, such as avibactam. Since it was discovered in 1996, approximately 160 KPC-variants have been reported, and KPC-2 and KPC-3 are the most prevalent ones. Ceftazidime/avibactam is currently considered the main therapy against KPC-2-producing bacteria, but, in the same year it was approved for clinical use in the USA, resistance was reported. Resistance to ceftazidime/avibactam is usually associated to KPC variants, such as KPC-31 and KPC-33, and rarely to KPC-8, KPC-23, KPC-40, KPC-76, and KPC-79. Here, we describe a new KPC-variant identified in a K. pneumoniae (isolate 416-8) isolated from a blood culture from the multicenter Antimicrobial reSistanCE iN bloodStream Infections in hOspitalized patieNts in BRazil (ASCENSION-BR) study. The isolate was identified to species level by MALDI-TOF MS, with a Microflex LT mass spectrometer (Bruker). Meropenem minimum inhibitory concentration (MIC) was determined by broth microdilution and ceftazidime/avibactam MIC was determined using the Sensititre system (Thermo Fisher Scientific). The isolate was submitted to whole genome sequencing, using Illumina MiSeq and Oxford Nanopore MinION. The raw reads were assembled with CLC (Qiagen), submitted to Pathogenwatch for strain typing and the hybrid genome was annotated with Prokka and analyzed by Mobile Element Finder (CGE platform). The blaKPC variant gene was submitted to BLAST (NCBI) and was aligned to the blaKPC gene that presented better percentage similarity, using Unipro UGENE software. The isolate 416-8 presented MICs of 2 and >32 mg/L for meropenem and ceftazidime/avibactam, respectively. The isolate belonged to ST 11 and two plasmids were identified: a hybrid plasmid IncFIB(pQil)/IncN carrying one copy of blaKPC gene; and a IncFII(K) plasmid, carrying blaTEM and virulence genes. The blaKPC gene presented high similarity to blaKPC-79 (99.67%) since the only difference was the insertion of one amino acid (serine) at position 182 of the protein, due to duplication of CCT at position 536 of blaKPC gene (Figure 1), which has not been reported as yet. Raw short reads were mapped to the new blaKPC variant and presented a coverage >500x. Similar to other isolates with KPC-79, the isolate 416-8 also demonstrated low meropenem MIC and resistance to ceftazidime/avibactam. As porin and efflux pumps alterations may also contribute to resistance to ceftazidime/avibactam, these resistance mechanisms will be further investigated in isolate 416-8.
Palavras-chave: KPC, variant, Klebsiella pneumoniae, ceftazidime/avibactam, antimicrobial resistance Agência de fomento:Instituto Nacional de Pesquisa em Resistência Antimicrobiana (INPRA) CNPq 465718/2014-0 | |||||