Disclosure(s): No relevant financial relationship(s) to disclose.
First Author: Aisha Naeem, MBBS Co-Author: Waleed Bin Ghaffar, MBBS, FCPS Anaesthesiology, FCPS Critical Care Medicine, EDIC, FCCS Instructor – Aga Khan University Co-Author: Muhammad Sohaib, FCPS Anaesthesia, FCPS Critical Care, FCCS Instructor – Assistant Professor, Fellowship Director Critical Care Medicine, Aga Khan University Hospital Co-Author: Tahir Munir, Phd Biostatistics – Senior Instructor, Aga Khan Univeristy Hospital Co-Author: Samie Dogar, MBBS, FCPS – Assistant Professor, Aga Khan University Hospital
Introduction: Sepsis and septic shock are leading causes of ICU mortality globally, with disproportionate impact in low- and middle-income countries (LMICs). Data on organism-specific patterns among ICU non-survivors are limited in these settings. This study analyzed associations between microbial profile, clinical severity, and ICU mortality in patients admitted with sepsis or septic shock to a surgical ICU in Pakistan.
Methods: This retrospective observational study included adult patients admitted to the surgical ICU of Aga Khan University Hospital, Karachi, between January 2016 and December 2023. All patients had a diagnosis of sepsis or septic shock at admission and documented ICU mortality. Data collected included demographics, clinical parameters, microbiology at admission and during ICU stay, severity indices (APACHE II, Charlson Comorbidity Index), and time of death. The primary outcome was the association between infection severity (sepsis vs. septic shock) and the number of organisms isolated on admission. Secondary outcomes included correlations of polymicrobial infection with APACHE II and Charlson Comorbidity index at ICU admission.
Results: Out of 3,686 ICU admissions, 242 non-survivors with sepsis or septic shock were included. Median age was 50 years (IQR: 32–63), with 65% male. At admission, 59% had septic shock. Gram-negative bacilli were most frequently isolated (17%), with E. coli, Acinetobacter, and Klebsiella predominant. Fungal isolates rose from 6.2% on admission to 36% during ICU stay. The number of organisms isolated at admission was higher in patients presenting with septic shock compared with those with sepsis, showing a moderate positive correlation with severity (R = 0.54). In contrast, no significant association was found between on admission polymicrobial infection and either APACHE II (R = –0.07) or Charlson Index (R = –0.04).
Conclusions: Among sepsis related ICU mortality, polymicrobial infection correlated with clinical severity (septic shock) at admission but not with physiological or comorbidity scores. The ICU stay was marked by a rising burden of fungal and drug-resistant pathogens. These findings highlight the need for early source control, local surveillance, and revised risk models that incorporate microbial complexity, especially in resource-limited settings.
