External ventricular drain infections: a retrospective analysis at a central hospital in KwaZulu-Natal, South Africa.

Abstract

Objectives We describe clinical, laboratory and microbiological characteristics of patients with suspected EVD-related infections (EVDRIs), colonisation and contamination. Methods An observational analytical retrospective descriptive cohort study was conducted on all positive cerebrospinal fluid (CSF) cultures from external ventricular drains (EVDs) at a referral hospital from 2019 - 2021. Episodes were categorised as infection, colonisation or contamination based on pre-defined clinical and laboratory characteristics. Demographic data, clinical information and identification and susceptibility results of microbes isolated from CSF were analysed for each of these episodes. Results One hundred and sixty-three patients were included with 337 positive CSF cultures. Positive cultures were grouped into 213 episodes; 76 (36%) infection, 13 (6%) colonisation and 124 (58%) contamination. The median duration of EVD insertion to infection was 17 days. In the infection group 58 episodes (76%) had low CSF glucose, persistently low or decreasing CSF glucose. Sixty-seven patient episodes (88%) had high CSF protein or increasing protein. The CSF white cell count (WCC) was higher in the infection group versus colonisation and contamination groups with a wide range. The causative organisms of EVDRIs were predominantly Enterobacterales (33%), extensively drug-resistant (XDR) A. baumannii (27.6%) and coagulase-negative staphylococci (CoNS) (13%). The causative organisms of EVD-related colonisation and contamination were predominantly CoNS. Conclusion Laboratory parameters (CSF glucose, protein and WCC) were useful to distinguish EVDRIs from colonisation and contamination. However clinical manifestations require correlation with laboratory abnormalities to diagnose EVDRIs. Multidrug resistant (MDR) Enterobacterales and extensively drug-resistant (XDR) A. baumannii were the commonest cause of EVDRIs.