Bloodstream infections in cancer patients in central India: pathogens and trends of antimicrobial resistance over a 5-year period

Introduction. Bloodstream infection (BSI) is a common complication with a high fatality rate in cancer patients. There are notable variations in the epidemiology of BSI over time and among different countries. Infections due to multidrug-resistant organisms (MDROs) such as extended-spectrum beta-lactamases (ESBLs) and carbapenem-resistant Enterobacteriaceae (CRE) are increasing. This may lead to inadequate empirical antibiotic therapy, increasing the antimicrobial resistance (AMR) problem and unfavourable outcomes in these immunocompromised patients. There is paucity of data pertaining to AMR in such vulnerable patients from developing countries such as India. The aim of this study was to investigate the distribution of the bacterial pathogens causing BSI and the AMR trend in cancer patients in central India. Methodology. This single-centre retrospective observational study was conducted in a tertiary care cancer hospital. Patients with solid organ and haematological malignancies, both adults and paediatric, who had blood cultures sent to the microbiology laboratory from January 2018 to December 2022 were included. Blood cultures were processed using the BacT/ALERT 3D system (bioMérieux, France), and the identification of the bacteria and their antimicrobial susceptibility (AST) was performed using the Vitek 2 compact system (bioMérieux, France). Electronic medical records and microbiology lab records were used to retrieve the demographic and microbiological data. Microsoft Excel (RRID:SCR_016137) was used to enter and tabulate the data. Statistical analysis was performed using SPSS version 29 (RRID:SCR_002865). Results. A total of 687 isolates from 524 patients were studied. Gram-negative bacteria (64%) were the commonest cause of BSI in the studied patients, followed by Gram-positive cocci (25%) and fungal isolates (9%). Ten cases were polymicrobial. Escherichia coli (n=140) was the most common among the isolated pathogens, followed by Klebsiella species (n=103), Pseudomonas species (n=102), and coagulase-negative staphylococci (CONS) (n=92). Among the 140 isolates of E. coli, 66% were extended-spectrum β-lactamase (ESBL) producers and 26% were resistant to carbapenem. Among the 103 isolated Klebsiella species, 50% were carbapenem resistant and 36% were ESBL producers. Among enterobacterales, the CRE rate was 34%. Carbapenem resistance was seen in 25% of Pseudomonas species and 53% of Acinetobacter species isolates. Klebsiella species were the most resistant pathogens isolated. CONS comprised 56% of all Gram-positive isolates, followed by Staphylococcus aureus (36%), enterococci species (11%), and streptococci species (3%). Methicillin resistance was 60% in CONS and 64% in S. aureus. One vancomycin-resistant enterococcus was isolated. Non-albicans Candida was the most common fungal pathogen. The sensitivity to fluconazole was 84% in non-albicans Candida species, while only one isolate of Candida albicans was resistant to fluconazole. The trend of pathogens was insignificant over 5 years, with Gram-negative bacteria being the commonest. Further, there was no significant change in the trend of ESBL and CRE resistance pattern over 5 years. Conclusion. Gram-negative bacteria were the most common isolated pathogens from BSI with a higher antimicrobial resistance rate in cancer patients. The CRE rate of 34% is alarming, limiting the choices for empirical antibiotic therapy.