A recent study conducted in Brazil has revealed alarming rates of multidrug-resistant Klebsiella pneumoniae strains causing community-acquired infections, particularly bloodstream and urinary tract infections. Published on March 20, 2025, the research underscores the growing public health threat posed by this pathogen, highlighting a pressing need for enhanced surveillance and preventive measures.
Klebsiella pneumoniae is recognized as a leading cause of both bloodstream infections (BSI) and urinary tract infections (UTI) globally. However, there is limited data regarding community-acquired cases, prompting researchers to characterize the clinical aspects and molecular features of K. pneumoniae isolates from community-acquired infections in Salvador, Brazil. The study involved the analysis of 65 isolates, comprising 24 CA-BSI cases and 41 CA-UTI cases, to evaluate their antimicrobial resistance profiles and genetic characteristics.
Findings revealed that older age, male gender, and underlying conditions such as kidney disease were predominantly associated with community-acquired bloodstream infections. Of particular concern was the antimicrobial resistance observed; the multidrug resistance (MDR) rate for K. pneumoniae from community-acquired infections was found to be 24.6%, while the carbapenem resistance rate stood at 4.6%. Among the CA-BSI isolates, 37.5% produced extended-spectrum beta-lactamase (ESBL), compared to just 9.8% in CA-UTI isolates, indicating a significant disparity in resistance profiles.
The study's authors noted that the presence of resistance genes was particularly notable; all ESBL-producing isolates contained either blaCTX−M−like or blaKPC−like genes, while blaKPC−like and blaNDM−like genes were uniquely found in CA-BSI strains. Such findings emphasize the importance of understanding these resistance mechanisms to inform treatment strategies and containment efforts.
A likely underlying factor for the observed differences in outcomes between CA-BSI and CA-UTI patients was the demographic data collected during the study. Patients diagnosed with CA-BSI were significantly older, with a median age of 76 years, compared to 47 years for those with CA-UTI. The prevalence of male patients was also markedly higher in the CA-BSI group (66.7%) than in the CA-UTI group (12.2%). Researchers posited that the higher frequency of comorbidities, especially kidney disease, especially impacts the severity of these infections in older males.
Further analysis highlighted the clinical outcomes for CA-BSI patients; nearly 25% died, with many of those having underlying health issues. This statistic raises concerns about the impact of multidrug-resistant K. pneumoniae strains among vulnerable populations, particularly the elderly.
Molecular characterization using pulsed-field gel electrophoresis and multilocus sequence typing revealed remarkably high clonal diversity among the isolates. The most prevalent sequence types were ST11 and ST15, which are associated with high-risk pandemic clones. An astonishing 81.3% of the MDR isolates belonged to these high-risk groups, underscoring the urgent need for strategies to combat the spread of these pathogenic variants.
Although the virulence profiles of K. pneumoniae isolates displayed similarities across both patient groups, instances of hypervirulent K. pneumoniae (hvKp) were noted, with one CA-BSI isolate and two from CA-UTI patients exhibiting hypervirulence biomarkers. These strains are exceptionally aggressive and could lead to severe infections, further complicating the treatment landscape.
This study, conducted from March 2015 to July 2023, underscores the necessity for better community surveillance of multidrug-resistant K. pneumoniae to manage its public health threat effectively. The findings reflect a dire need for enhanced educational campaigns focusing on antibiotic stewardship and informed public awareness regarding the use of antibiotics.
In conclusion, the prevalence of multidrug-resistant K. pneumoniae in community-acquired infections in Brazil identified in this study points to a pressing public health issue. Researchers warn that without immediate action to address antibiotic resistance, these infections could lead to higher morbidity and mortality rates in the community. According to the authors, establishing a comprehensive resistance monitoring system for community-acquired infections in Brazil is a crucial step in mitigating this growing health crisis.
