Introduction Bloodstream infection is a major cause of morbidity and mortality in hospitalized patients despite advances in antimicrobial therapy and in supportive care. The proportion of blood stream infection caused by gram- negative bacilli is increasing worldwide. Hospitals in the United States participating in the National Nosocomial Infections Surveillance (NNIS) System reported that by 2003 gram-negative bacilli were responsible for 24 percent of nosocomial bacteraemia cases in intensive care units. 1 In some areas of Europe and the Far East, the proportion of bacteraemia caused by gram-negative bacilli was greater than that identified in the United States. 2 This is of concern since gram-negative bacillary sepsis with shock has a mortality rate of 30 to 50 percent. 3,4 Gram negative bacteraemia has become a serious therapeutic problem due to emergence of multidrug resistance (MDR), defined as acquired non- susceptibility to at least one agent in three or more antimicrobial categories. 5-7 In South East Asia, the emergence of the New Delhi metallo-b-lactamase-1 (NDM-1) in enterobacteraciae was reported in 2009. 8 Metallo- b-lactamases are enzymes that mediate resistance to various b-lactam agents, including carbapenems. Infection with MDR pathogens leads to increased mortality, length of hospital stay and cost, especially among the critically ill, immunocompromised and those exposed to invasive procedures. 9,10 The importance of appropriate and timely empirical antibiotic therapy for a favourable outcome in gram negative bacteraemia is well documented but therapeutic options are limited in infection with resistant strains. 11 There are several reports on outcomes of gram negative bacteraemia but there are limited reports on risk factors for mortality due to gram negative bacteraemia and risk factors for carbapenemase resistant organisms, particularly from developing countries like Pakistan. 12 This study aims to describe the risk factors for mortality due to gram negative bacteraemia, and evaluate the risk factors for carbapenem resistant bacteraemia in adults at a tertiary care hospital in Pakistan. Vol. 64, No. 5, May 2014 530 ORIGINAL ARTICLE Risk factors for carbapenem resistant bacteraemia and mortality due to gram negative bacteraemia in a developing country Kiran Kalam, 1 Farah Qamar, 2 Sunil Kumar, 3 Sajjad Ali, 4 Shehla Baqi 5 Abstract Objective: To identify the risk factors for carbapenem resistant bacteraemia and mortality due to gram negative bacteraemia in a developing country. Methods: A prospective cohort study was conducted at the Sindh Institute of Urology and Transplantation (SIUT) from June to October 2012. Hospitalized patients > 15 years of age with gram negative bacteraemia were included and followed for a period of 2 weeks for in hospital mortality. Data was collected and analyzed for 243 subjects. Multivariate analysis was used to determine the risk factors for carbapenem resistant bacteraemia and mortality due to gram negative bacteraemia. Crude and adjusted odds ratio and 95% CI are reported. Results: A total of 729 out of 1535 (47.5%) cultures were positive for gram negative isolates. Out of 243 subjects, 117 (48%) had an MDR isolate. Having an MDR isolate on culture (AOR, 2.33;95% CI, 1.35 -4.0), having multiple positive cultures (AOR, 1.8; 95% CI, 0.94 -3.4) and stay in ICU >48 hours (AOR, 2.0 ; 95% CI, 1.12 -3.78) were identified as significant risk factors for mortality due to gram negative organisms. Risk factors for carbapenem resistant bacteraemia were age >50 years (AOR, 1.83; 95% CI, 1.0-3.5), septic shock on presentation (AOR 2.53; 95% CI, 1.03 -6.2) , ICU stay of >72 hours (AOR 2.40; 95% CI, 1.14-5.0) and receiving immunosuppressant medications (AOR 2.23; 95% CI, 0.74 - 6.7). Conclusion: There is a high burden of MDR and carbapenem resistant gram negative bacteraemia, with a high mortality rate. Keywords: Gram negative bacteraemia, Mortality, Developing country, Multidrug resistance, Carbapenemresistance. (JPMA 64: 530; 2014) 1,3-5 Sindh Institute of Urology and Transplant, Karachi, 2 Department of Paediatrics and Child Health, Aga Khan University Hospital, Karachi. Correspondence: Kiran Kalam. Email: kirankalam78@gmail.com