Background: Blood stream infection(BSI) is a major cause of mortality in solid organ transplant recipients.  Gram negative bacteremia (GNB) is most common cause of BSI in renal transplant recipients (RTR). The risk factors are cytomegalovirus infection (CMV), pre-transplant dialysis, acute rejection, urological abnormalities and ureteral stent. The mortality associated with bacteremia is around 2.5 to 11%. Considering the huge impact on morbidity and mortality, our aim is to analyze the risk factors and outcome of GNB in RTRs.
Methods: A retrospective cohort study was done at Sindh Institute of Urology and Transplantation (SIUT), Karachi, Pakistan. SIUT is the largest transplant center of Pakistan. The files of all renal transplant recipients >12 years of age who had documented GNB from January 2015 till June 2017 were reviewed and followed till December 2019. The first episode of GNB was taken.  Baseline characteristics and clinical features were noted. Whether received ATG, solumederal or rituximab, surgical intervention, concomitant infections were documented in the last 3 months of bacteremia.  Any invasive devices during the episode of bacteremia, source of bacteremia, microbiology with sensitivity were also noted. The graft function and all-cause mortality till 2019 was also noted.
Results: Out of 910 patients, 35 (3.8%) developed gram negative bacteremia. The mean age was 30±11years, 60% males. Around 26 (74%) had one haplotype match. Induction with ATG was received by 7(20%). In the last 3 months of bacteremia, 3(8%) each  received solumederol and ATG and 1 (2.7%) rituximab for rejection. The time since transplant is shown in fig 1. CMV viremia was found in 10 (28.6%) post-bacteremia. Around 27 (77%) had urinary tract infection (UTI) as a source of bacteremia. E-coli was the most common organism 25(69%), 68% were ceftriaxone resistant. Fever was found in only 51% of the patients and 20 (55.5%) had normal leukocyte count. Recurrent bacteremia was seen in 5(14%) within 6 months. The trend of graft function is shown in fig 2. At the last follow-up 4 (11%) had graft failure which occurred at an average of 3 years post- bacteremia. At total of 2 patients died at an average of 1 year post bacteremia. 
Conclusion: Gram negative bacteremia was found in 4% of transplant recipients. Half of the patients develop bacteremia 6 months post-transplant. UTI was the most common cause. Patients did not mount symptoms, only 50 % had fever and leukocytosis. One fourth of the patients developed CMV viremia after bacteremia. At the end of bacteremia, graft functions got deranged however; there was no graft failure and deaths attributable to bacteremia.