Risk factors and outcomes associated with acquisition of colistin-resistant KPC-producing Klebsiella pneumoniae: a matched case-control study

Abstract

A matched 1:3 case-control study investigated factors predicting colistin-resistant versus colistin-susceptible KPC-producing Klebsiella pneumoniae acquisition and its impact on patient outcomes. Case patients were more often admitted from other institutions (P = 0.019) and had longer therapy with beta-lactam/beta-lactamase inhibitors (P = 0.002) and higher overall mortality (P = 0.05). All 52 study isolates were clonally related, suggesting horizontal dissemination. None of these parameters independently predicted colistin resistance, which probably occurred in a susceptible KPC-KP strain that was subsequently disseminated horizontally.

FIG. 1.

PFGE profiles of 12 CR KPC-KP and 10 CS KPC-KP isolates representing all subtypes of the single KPC-KP clone. Lanes M, lambda phage molecular size marker; lanes c1 to c3, three contemporary KPC-negative K. pneumoniae isolates recovered during the study period; lanes 1 to 10 and 12, CR KPC-KP of the subtype Ia; lane 11, CR KPC-KP of the subtype Ib; lanes 13 to 16, 18, 19, and 22, CS KPC-KP of the subtype Ia; lane 17, CS KPC-KP of the subtype Ic; lane 20, CS KPC-KP of the subtype Id; lane 21, CS KPC-KP of the subtype Ie.