Clinical Features of Patients with Carbapenem Nonsusceptible Klebsiella Pneumoniae and Escherichia Coli in Intensive Care Units: a Nationwide Multicenter Study in Taiwan

Background: Patients in intensive care units (ICUs) are especially prone to colonization and infection by carbapenem-resistant Enterobacteriaceae. We conducted a multicenter investigation to study the clinical and microbiological characteristics of patients with carbapenem nonsusceptible Klebsiella pneumoniae and Escherichia coli in ICUs of Taiwanese hospitals.

Methods: Patients with carbapenem nonsusceptible K. pneumoniae and E. coli in ICUs from nine medical centers and eight regional hospitals in Taiwan were enrolled in 2012. Carbapenem nonsusceptibility was defined as a minimum inhibitory concentration of at least 2 mg/L for imipenem or meropenem. Clinical characteristics and risk factors for 30-day mortality were analyzed. Isolates were screened for antibiotic susceptibility and β-lactamase genes.

Results: A total of 66 cases infected (n = 46) or colonized (n = 20) with carbapenem nonsusceptible K. pneumoniae (n = 60) and E. coli (n = 6) were identified during the study period. Nineteen isolates had genes that encoded carbapenemases (28.8%), including Klebsiella pneumoniae carbapenemase-2 (KPC-2) (n = 14), imipenemase-8 (IMP-8) (n = 1), Verona integron-encoded metallo-β-lactamase (VIM) (n = 3), and New Delhi metallo-β-lactamase-1 (NDM-1) (n = 1). The in-hospital mortality associated with non-susceptible K. pneumoniae and E. coli was 50%. The 30-day mortality of the 46 patients with infection was 50%. Septic shock was the only independent risk factor for 30-day mortality in patients with infection. The 30-day mortality rate was similar between patients with combination therapy and monotherapy.

Conclusion: Patients who acquired carbapenem nonsusceptible K. pneumoniae and E. coli in ICUs have a high mortality rate. Further clinical study is needed to deal with this emerging challenge.