OBJECTIVES: During the COVID-19 pandemic, there has been an increase in antibiotic resistance, particularly among gram-negative bacteria. However, there is currently a lack of national data regarding the susceptibility of K. pneumoniae in Brazil. This study aimed to analyze the in vitro susceptibility of K. pneumoniae isolates collected from 9 sites in Brazil between 2020-2021, as part of the Study for Monitoring Antimicrobial Resistance Trends (SMART) global surveillance program.

METHODS: Non-duplicate clinical isolates of K. pneumoniae collected from 9 Brazilian sites between Jan/2020 and Dec/2021 were analyzed for susceptibility to amikacin (AMK), cefepime (FEP), ceftriaxone (CRO), colistin (COL), imipenem (IMI), imipenem/relebactam (IMR), ceftazidime/avibactam (CZA), levofloxacin (LVX), meropenem (MEM) and piperacillin/tazobactam (P/T) according to EUCAST 2023. Only isolates from lower respiratory tract infection (LRTI) and from patients above 18 years old were included. Susceptibility and distribution of beta-lactamase encoding genes among Klebsiella pneumoniae carbapenemase (KPC)-producing isolates were also investigated.

RESULTS: A total of 232 isolates were analyzed. The commonly used antibiotics, MEM and IMI, exhibited susceptibilities of 47.8% and 40.1%, respectively. COL and AMK, typically reserved for highly resistant isolates due to their associated toxicity, showed susceptibilities of 76.3% and 74.1%, respectively. New antibiotics, CZA and IMR, demonstrated high in vitro susceptibility rates of 89.6% and 88.8%, respectively. Regarding beta-lactamase encoding genes in KPC-producing isolates (n=122), almost all isolates (97.5%) exhibited KPC-2 production. In KPC isolates non-susceptible to COL, CZA and IMR maintained susceptibility of 97.7% and 95.4%, respectively.

CONCLUSIONS: This study highlights an elevated prevalence of KPC-producing K. pneumoniae from the LRTI in Brazil, which underscores the urgent need to implement strategies to combat antimicrobial resistance. Furthermore, IMR is a new antibiotic that maintains high in vitro activity even in resistant isolates and can serve as another important treatment option for pneumonia caused by K. pneumoniae.