Temporal Trends in Antibiotic Resistance of Klebsiella pneumoniae and Antibiotic Consumption: A Six-year Longitudinal Surveillance Study

Antimicrobial resistance in Klebsiella pneumoniae represents a major challenge to healthcare systems. While antibiotic consumption is a key driver of resistance, long-term, setting-specific data linking antimicrobial use with resistance trends remain limited. This study aimed to evaluate temporal trends in antibiotic consumption and corresponding resistance patterns in K. pneumoniae over a six-year period. This retrospective, longitudinal surveillance study was conducted at a tertiary-care hospital from January 2019 to December 2024. Non-duplicate K. pneumoniae isolates recovered from various specimens were included. Antimicrobial susceptibility testing was performed using standardized laboratory methods and interpreted accordingly. Antibiotic consumptions data were extracted from electronic records, and quantified annually, with stratification by ICU and non-ICU settings. Temporal trends in resistance and consumption were analysed descriptively using various graphical representation. Over the time, antibiotic consumption demonstrated a progressive shift toward broader spectrum and reserve agents, with a sustained increase in carbapenem use and persistently high fluoroquinolone utilization. Fluoroquinolone susceptibility remained uniformly low despite continued high use, whereas carbapenem susceptibility showed temporal fluctuations with an overall declining trend in later years. A transient improvement in susceptibility across multiple classes was observed in 2021, followed by renewed erosion thereafter. In contrast, aminoglycosides and tigecycline retained relatively stable activity, paralleling their restrained use. This six-year surveillance study highlights parallel temporal trends between antibiotic consumption patterns and evolving resistance in K. pneumoniae, with pronounced effects in critical care and bloodstream infections. Integrating consumption data with resistance surveillance is essential to inform setting-specific antimicrobial stewardship strategies and preserve the effectiveness of existing antibiotics in high-resistance healthcare environments. A six-year longitudinal surveillance study evaluated antibiotic consumption and resistance trends in Klebsiella pneumoniae. Carbapenem use increased over time, with corresponding declines in susceptibility particularly in ICU bloodstream infections. Fluoroquinolone utilization remained high despite persistently low K. pneumoniae susceptibility across settings. Bloodstream and ICU isolates exhibited consistently higher resistance compared with non-invasive and ward isolates. Restrained use of aminoglycosides and tigecycline was associated with relatively preserved antimicrobial activity.