KPC-3 Klebsiella pneumoniae ST258 clone infection in postoperative abdominal surgery patients in anintensive care setting: analysis of a case series of 30 patients

Objective: We studied the clinical course, Intensive Care Unit (ICU) and hospital outcomes of 30 postoperativeabdominal surgery patients who showed severe infections caused by Klebsiella pneumoniae Sequence Type 258producing K. pneumoniae carbapenemase 3 (KPC-Kp). Methods: Patients with at least two positive bloodcultures for KPC-Kp after admission to the ICU were recruited for a 12-month period and treated with acombination regimen of colistin plus tigecycline. They were started on a high-dose (initial dose of 200 mg then100 q12) of tigecycline combined with colistin, taking into account intra-abdominal abscess severity and MCIsfor tigecycline. Results: The average age of the patients was 56.6 ± 15 (male = 16, female = 14), averageAPACHE score on admission was 22.72. Twenty out of 30 patients (66%) came from the surgical emergencyunit. Patients showed KPC-Kp postoperative infection as follows: intra-abdominal abscess in 15 patients (50%),anastomotic leakage in 8 (24%), surgical site infection (SSI) in 4 (12%) and peritonitis in 3 (10%). Overallcrude mortality rate in the ICU due to infection was 40% (12 out of 30 patients). Twelve out of 30 patients(40%) were started on a combination treatment of high-dose tigecycline and intravenous colistin; five of themshowed tigecycline MICs of 0.8 - 1. Mortality was significantly associated with a greater number of surgicalprocedures, previous ICU admission (<0.0005), APACHE II ( p=0.018)and SOFA score (p<0.0005) and VAP(0.013). Treatment with high doses of tigecycline obtained a favourable outcome in patients with intraabdominalabscess. Discussion: Critically-ill surgical patients with KPC-Kp infections have to be treated in atimely manner, taking into account the severity of post-operative complications such as intra-abdominal abscessand anastomotic leakage. In these cases, early suspicion and detection are essential to reducing infection-relatedmorbidity and mortality. Finally, studies evaluating antibiotic combination therapy and well-controlled clinicaltrials are needed to define the optimal treatment of infections caused by KPC-Kp and, more generally,carbapenem-resistant bacteria.