Outcomes of a universal screening program for CPE in the UK
Carbapenemase-producing Enterobacteriaceae (CPE) infections are emerging as a significant threat to healthcare worldwide. Some regions in Asia and Europe report CPE as endemic, with outbreaks of infection more widely reported in the US and UK. Otter JA et al. (J Antimicrob Chemother 2016 DOI: 10.1093/jac/dkw309) sought to determine the prevalence of CPR colonisation in a hospital cohort at time of admission.
Between February and May 2015, adult patients admitted to a UK tertiary healthcare facility were approached within 72 hours of admission. Consent was obtained, a rectal swab was collected, and standardised questionnaire was completed.
Overall, 4567 patients were approached to participate in the study. Of these, 4006 (87.7%) provided a rectal swab and completed risk factor questions. 435 (9.5%) answered risk factor questions but did not provide a rectal swab, and 126 (2.8%) did not answer risk factor questions or submit a swab. Six CPE were cultured from 5 of the 4006 screened patients (0.1%). Three patients were colonised with Escherichia coli, one patient was colonised with Citrobacter frundeii, and one patient was colonised with E. coli and Klebsiella pneumonia. Of these isolates, 4 were OXA-48 and 2 were NDM carbapenemases. 41.9% of patients had an overnight stay in a UK hospital in the 12 months prior, and 54.1% had taken antibiotics in the last 6 months. Hospitalisation abroad was significantly associated with CPE colonisation (OR 64.3, p<0.001).
Findings demonstrate an extremely low prevalence of CPE carriage in an unselected cohort of hospitalised patients in the UK. Targeting patients with recent overseas hospitalisation is the most appropriate measure for guiding screening practices in this setting.
Evaluating an alternative method of surveillance for central line-associated bloodstream infection in patients with cancer
In recognition of the potential for bloodstream infections in cancer patients to arise from the gastrointestinal tract, and the impact of this upon central line-associated bloodstream infection surveillance, National Healthcare Safety Network surveillance criteria include the definition of mucosal barrier injury (MBI) laboratory-confirmed bloodstream infection. In contrast, the clinical definition of catheter-related bloodstream infection (CRBSI) proposed by the Infectious Diseases Society of America stipulates simultaneous quantitative blood cultures drawn from central and peripheral sites or calculation of differential time to positivity of these culture results, to confirm CRBSI. Chaftari A-M C, et al. (Am J Infect Control 2016; 44:931-934) sought to compare these definitions in cancer patients managed at a US cancer centre.
This retrospective evaluation was performed in patients managed at the M.D. Anderson Cancer Center between January 2013 and March 2014. CLABSI and MBI were classified according to NHSN criteria, and CRBSI according to the IDSA definition. To enable application of all definitions, only cases having 2 positive simultaneous blood cultures drawn from the CVC and peripheral site or any blood culture and a quantitative catheter tip growing the same organism were selected.
Of 426 CLABSI events during the study period, 149 were eligible for evaluation. Seventy of these 149 (47%) had definite CRBSI, and 63 (42%) fulfilled criteria for MBI bloodstream infection. CRBSI was more commonly defined in patients with no MBI, when compared with those having MBI (69% vs. 18%).
Findings are consistent with earlier published works, suggesting that the NHSN criteria may over-estimate the CVC as the source of BSI – only 47% of those meeting CLABSI criteria had confirmed CRBSI. Notably, 17% of those with MBI laboratory-confirmed bloodstream infection met criteria for CRBSI, suggesting that the exclusion of cancer patients with MBI as a source for infection could potentially miss CRBSI events. The major limitation of this study is that CRBSI criteria could not be applied in the majority of cancer patients (65%) - this definition requires 2 positive blood cultures, and is also reliant upon confirmatory laboratory testing which may not be provided routinely. Therefore, the utility of the CRBSI definition as a pragmatic method for device-related bloodstream infection surveillance is limited.