Study selection

Articles were eligible if they included any patients with infections due to carbapenemase-producing K. pneumoniae treated with triple combination antimicrobial therapy for a minimum of 48 h. When an article included patients treated with triple combination therapy along with mono or dual antimicrobial therapy, only the triple combination data were extracted. Articles were excluded from further review if they fulfilled any of the following criteria: (1) the study evaluated Enterobacteriaceae other than K. pneumoniae; (2) the study included data based on only in vitro or in vivo infection models; (3) the details regarding the treatment regimens were not specified or included in the article; and (4) if the study only reported on patients colonized with CPKP.

Following initial identification, all potential articles were reviewed to assess their eligibility based on treatment and microbiology-specific exclusion criteria. Articles were ineligible if they fulfilled any of the following criteria: (1) carbapenemase production was not confirmed; (2) data related to CPKP could not be separated from other carbapenemase-producing Enterobacteriaceae; and (3) details regarding treatment with monotherapy or dual combination therapy specifically for the CPKP infection were included. One article was excluded as an updated version of the same study population was published soon afterwards. The authors were contacted in cases where details regarding the concurrent administration of antibiotics as a part of the triple combination were not clearly stated or could not be verified.