Outbreaks of colistin-resistant and colistin-susceptible KPC-producing Klebsiella pneumoniae in a Brazilian intensive care unit

Carbapenem-resistant Enterobacteriaceae (CRE), especially those that produce Klebsiella pneumoniae carbapenemase (KPC) and are associated with colistin resistance, pose a severe health threat due to the limited treatment options. To describe two outbreaks of KPC-producing K. pneumoniae in an adult intensive care unit (AICU) in Brazil. In May 2015, 14 patients had colistin-susceptible KPC-producing strains (ColS-KPC), and in July 2015, nine patients had colistin-resistant KPC-producing strains (ColR-KPC). Between September 2014 and August 2015, we performed surveillance at a university hospital and all CRE were tested for blaKPC genes. Clonality was investigated by pulsed-field gel electrophoresis. Resistance to colistin was confirmed by broth microdilution method. Consumption of carbapenems and colistin was expressed as defined daily doses. In all, 111 patients with CRE were identified during the surveillance period; K. pneumoniae was the major isolate (77.13%). The two outbreaks were identified when infection rates (KPC per 1000 patient-days) exceeded the background level. Rates of carbapenem and colistin consumption were high. Control measures (bedside alcohol gel, contact precautions, regular rectal swabs) did not curtail the outbreaks. Mortality rates were 42.9% and 44.4% for ColS-KPC- and ColR-KPC-infected patients, respectively. After the death of four infected patients with ColR-KPC, the unit was closed to new admissions. Our experience demonstrates the serious risks presented by KPC, and especially ColR-KPC, in Brazilian AICUs. Selective pressure from excessive antibiotic use and transmission on healthcare workers' hands were likely the major factors in transmission.