Colistin is considered as one of the last resort of antibiotics against carbapenem resistant enterobacteriaceae. During the last decade, increased use of colistin or polymyxins due to the increasing prevalence of carbapenem resistant gram-negative bacteria has unfortunately led to the emergence of colistin resistant strains. There are no defined antibiotic regimens for colistin resistant strains which makes the treatment of these organisms extremely challenging. We therefore report the clinical spectrum and outcomes of infections due to colistin-resistant carbapenem resistant Enterobacteriaceae (Co-CRE) as well as the factors associated with acquisition of Co-CRE.
We conducted a retrospective cross sectional study from January, 2013 till December, 2017 on patients admitted to a tertiary care hospital in Karachi, Pakistan. Statistical analysis was done using SPSS 19.
Forty patients with Co-CRE were identified of which 29 (72.5%) were males. Median age was 54.5 years. The most common organism isolated was Klebsiella in 22 (55%) followed by Providencia in 5 (12.5%) patients. Most common source of infection was the lung in 12 (30%) followed by urine in 11 (27.5%) patients. Similarly, the most common cause of bacteremia was pneumonia followed by intra-abdominal infections (50% and 37.5% of bacteremia cases respectively). Twenty eight (70%) patients had prior cultures with multi-drug resistant organisms and 36 (90%) had used antibiotics in the past. A quarter (10) patients had pan resistant Co-CRE strains while of the remaining strains 66% were sensitive to Fosfomycin. All patients received Colistin based regimen in combination with 2 or 3 of the following: carbapenem, Fosfomycin, Amikacin, Co-triamoxazole and Tigecycline. Complete clinical cure was achieved in only 50% of patients whereas microbiological eradication was achieved in 75%. Higher PITT bacteremia score, solid organ transplant and acute kidney injury were associated with mortality in patients with Co-CRE.
Infections with Co-CRE was seen in patients with prior nosocomial exposures and led to poor outcomes, despite combination treatment guided by susceptibilities.
F. Sharif, None
M. Aijaz, None
S. Awan, None
B. Jamil, None