Competitive Transmission of Carbapenem-Resistant Klebsiella pneumoniae in a Newly Opened Intensive Care Unit

We conducted a 6-month prospective study in a newly opened ICU for high-resolution tracking of carbapenem-resistant Klebsiella pneumoniae (CRKP) through environmental surveillance, patient screening, and genome sequencing. Among all ICU patients (n = 348) screened, 3.5% carried CRKP on admission and 16.3% acquired CRKP thereafter. CRKP was not detected in the environment until 10 weeks and was then isolated from 98 of 2,989 environmental samples (3.3%). The first CRKP isolate from rectal swabs (n = 37) and the first clinical isolate (n = 8) of each patient as well as the 98 isolates from environmental were subjected to whole-genome sequencing. The 143 CRKP isolates from patients and environment samples were assigned to four sequence types, with ST11 dominating (95.8%) and further divided into 14 clones, suggesting introduction of multiple clones. Subsequent CRKP transmission was complex and dynamic with 10 clones found in multiple patients and seven also detected in the environment. Two particular ST11 clones caused extensive (≥5 rooms) and persistent (≥10 weeks) environmental contamination. Both clones were associated with patients who carried CRKP throughout their prolonged ICU stay. Such "super-contaminators" are a priority for isolation and environmental surveillance. IMPORTANCE Carbapenem-resistant Klebsiella pneumoniae (CRKP) is a global challenge for human health. In health care settings, patients have frequent interactions with other patients and the environment, rendering challenges for untangling the introduction and transmission of CRKP. We conducted a prospective surveillance study in a newly opened ICU for high-resolution tracking of CRKP. Our study demonstrated the dynamic, complicated transmission of CRKP and has important findings that may help to curb its spread in health care settings. First, compliance with basic measures such as routine environment cleaning and postdischarge terminal cleaning is needed to minimize the environmental contamination-driven spread. Second, active screening could demonstrate the scale of the problem, and room transfer of patients with CRKP should be prohibited whenever possible. Third, the priority for single-room isolation should be given to patients with prolonged carriage of CRKP, especially in resource-limited settings. Good infection control practice lays a foundation for tackling multidrug-resistant organisms like CRKP.