1585. Epidemiology & Risk Factors for Colistin-Resistant Gram-Negative Infections in an Inner City Tertiary Care Hospital
Session: Poster Abstract Session: Multidrug-Resistant Gram Negative Rods
Saturday, October 5, 2013
Room: The Moscone Center: Poster Hall C

The emergence of infections caused by colistin-resistant Gram-negative organisms (CRO) is a major healthcare concern. We performed a retrospective analysis to gain a better understanding of the epidemiology of CRO infections within our own institution.


We conducted a retrospective study of patients with positive cultures for CRO (minimum inhibitory concentration, MIC >2 µg/ml) at our institution from October 2007 to March 2012.  Microbiology logs and medical records were reviewed to identify study patients and to obtain data including patient demographics,  prior healthcare exposure, colistin use, MICs of study isolates, comorbidities, and outcomes 30 days from the time of documentation of the infection.


98 patients had one or more cultures positive for CRO (total of 150 isolates). The majority (72 %, n=109) of CRO were from genitourinary and respiratory tract specimens, particularly in critical care patients. Klebsiella pneumoniae and Pseudomonas aeruginosa were the most common CRO isolated, with median colistin MICs of 6 µg/ml and 3 µg/ml, respectively. Our population was heterogeneous: black (53%), Hispanic (22%), white (20%), and Asian (4%). Men and women were equally represented; average age was 52 years.  96 patients acquired CRO infections in the hospital setting and 20% (n=20) had documented colistin use within 1 year prior to CRO identification. 75% of patients had indwelling devices in place. Patients had multiple comorbidities, including hypertension in 40% and diabetes mellitus in 37%; 38% were transferred from another healthcare facility. 46 patients were screened for human immunodeficiency virus infection; 13 were positive. Incidence of CRO infections varied from year to year (range 16 to 51/yr).  30% of our patients with CRO died within 30 days of infection; only 30% of patients were discharged home.


CRO infections are not uncommon in our institution and occur in patients with multiple comorbid conditions, indwelling devices, critical illnesses and healthcare exposure.  Heightened vigilance for CRO and a better understanding of the epidemiology and optimal treatment is needed to reduce the significant morbidity and mortality of these infections.

Frantz Pierre-Louis, MD1, Shin-Pung Jen, PharmD2 and Lisa Dever, MD1, (1)Infectious Diseases, UMDNJ-New Jersey Medical School, Newark, NJ, (2)University Hospital, Newark, NJ


F. Pierre-Louis, None

S. P. Jen, None

L. Dever, None

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