The emergence of Klebsiella pneumoniae carbapenemases (KPCs) producing bacteria has become a significant global public health challenge while the optimal treatment remains undefined. Lee and Burgess (2012) performed a systematic review of published studies and reports of treatment outcomes of KPC infections using Medline (2001-2011).
Articles or cases were excluded if one of the following was fulfilled: no individual patient data provided, no treatment regimen specified, no treatment outcome specified, report of colonization, or greater than three antibiotics were used to treat the KPC infection. Data extracted included patient demographics, site of infection, organism, KPC subtype, antimicrobial therapy directed at KPC-infection, and treatment outcome. Statistical analysis was performed in an exploratory manner. A total of 38 articles comprising 105 cases was included in the analysis.
The researchers report that the majority of infections was due to K. pneumoniae (89 percent). The most common site of infection was blood (52 percent), followed by respiratory (30 percent), and urine (10 percent). Forty-nine (47 percent) cases received monotherapy and 56 (53 percent) cases received combination therapy directed at the KPC-infection. Significantly more treatment failures were seen in cases that received monotherapy compared to cases who received combination therapy (49 percent versus 25 percent; p= 0.01).
Respiratory infections were associated with higher rates of treatment failure with monotherapy compared to combination therapy (67 percent versus 29 percent p= 0.03). Polymyxin monotherapy was associated with higher treatment failure rates compared to polymyxin-based combination therapy (73 percent versus 29 percent; p= 0.02); similarly, higher treatment failure rates were seen with carbapenem monotherapy compared to carbapenem-based combination therapy (60 percent versus 26 percent; p= 0.03).
Overall treatment failure rates were not significantly different in the three most common antibiotic-class combinations: polymyxin plus carbapenem, polymyxin plus tigecycline, polymyxin plus aminoglycoside (30 percent, 29 percent, and 25 percent respectively; p=0.6).
The researchers conclude that combination therapy is recommended for the treatment of KPC infections; however, which combination of antimicrobial agents needs to be established in future prospective clinical trials. Their research was published in Annals of Clinical Microbiology and Antimicrobials.
Reference: Lee GC and Burgess DS. Treatment of Klebsiella Pneumoniae Carbapenemase (KPC) infections: a review of published case series and case reports. Annals of Clinical Microbiology and Antimicrobials 2012, 11:32 doi:10.1186/1476-0711-11-32