Evaluation of Specific Risk Factors and Outcomes of Colistin-Resistant Klebsiella pneumoniae Infections in a Tertiary Care Centre - An Observational Study

Abstract

Background: Incidence of multidrug resistant Klebsiella pnumoniae infections are increasing globally especially in ICUs. Aim: We evaluated the burden of colistin resistant K. pneumoniae (ColR KP) and the risk factors associated with the outcome of these patients. Methods: Consecutive patients developing K. pneumoniae infections were included. K. pneumoniae from endotracheal tube and catheterized urine sample, having cell count <105 cfu/ml, and which did not necessitate a change in antibiotics as per the treating physicians was considered as colonizer. Demographic and clinical details were collected and samples were processed as per standard protocol. Any growth was identified and its antimicrobial susceptibility was carried out by using Vitek 2 automated system. Minimum inhibitory concentration of >4 μg/ml for Colistin was considered as resistant. The resistant isolates were confirmed with Broth microdilution method. Risk factor associated with the outcome of ColR KP was analyzed. Findings: Burden of K. pneumoniae infection was 50.02 per 1000 admissions. K. pneumonie (n=155) was isolated from patients with ventilator associated pneumonia (84, 54.2%), followed by blood stream infection (49, 31.6%) and urinary tract infection (22, 14.2%). ColR KP and intermediate (ColI KP) isolates were 58 (37.41%) and 97 (62.6%) respectively. Among ColR KP infected patients 32 (55.1%) died whereas 26 (44.8%) patients were discharged. Higher mortality was witnessed in ColI KP cases (75, 77.3%) compared to ColR-KP cases (32, 55.1%) (p=0.004; OR=2.77; 95% CI=1.37 to 5.59). Colistin resistance and presence of central line were independently associated with mortality. Conclusion: Colistin resistant K. pneumoniae infections among ICU patients are on rise. Presence of central venous catheter and resistance to colistin were independent predictors of mortality.