Molecular Comparison of Bacterial Communities on Peripheral Intravenous Catheters and Matched Skin Swabs.

Claire M. Rickard,David J. McMillan,Nicole Marsh,David L. Paterson,Md Abu Choudhury,Shahera Banu,Raymond Schuch

doi:10.1371/journal.pone.0146354

Abstract

Skin bacteria at peripheral intravenous catheter (PIVC) insertion sites pose a serious risk of microbial migration and subsequent colonisation of PIVCs, and the development of catheter related bloodstream infections (CRBSIs). Common skin bacteria are often associated with CRBSIs, therefore the bacterial communities at PIVC skin sites are likely to have major implications for PIVC colonisation. This study aimed to determine the bacterial community structures on skin at PIVC insertion sites and to compare the diversity with associated PIVCs. A total of 10 PIVC skin site swabs and matching PIVC tips were collected by a research nurse from 10 hospitalised medical/surgical patients at catheter removal. All swabs and PIVCs underwent traditional culture and high-throughput sequencing. The bacterial communities on PIVC skin swabs and matching PIVCs were diverse and significantly associated (correlation coefficient = 0.7, p<0.001). Methylobacterium spp. was the dominant genus in all PIVC tip samples, but not so for skin swabs. Sixty-one percent of all reads from the PIVC tips and 36% of all reads from the skin swabs belonged to this genus. Staphylococcus spp., (26%), Pseudomonas spp., (10%) and Acinetobacter spp. (10%) were detected from skin swabs but not from PIVC tips. Most skin associated bacteria commonly associated with CRBSIs were observed on skin sites, but not on PIVCs. Diverse bacterial communities were observed at skin sites despite skin decolonization at PIVC insertion. The positive association of skin and PIVC tip communities provides further evidence that skin is a major source of PIVC colonisation via bacterial migration but microbes present may be different to those traditionally identified via culture methods. The results provide new insights into the colonisation of catheters and potential pathogenesis of bacteria associated with CRBSI, and may assist in developing new strategies designed to reduce the risk of CRBSI.

Highlights

The insertion of a vascular catheter is a major risk factor associated with nosocomial infection [1]
None of the peripheral intravenous catheter (PIVC) and associated skin samples was positive in bacterial growth on culture
Sixty-one percent of all reads from the PIVC tips and 36% of all reads from the skin swabs belonged to this genus

Summary

Introduction

The insertion of a vascular catheter is a major risk factor associated with nosocomial infection [1]. CRBSIs increase a patient’s risk of death, length of hospital stay, and are a significant cost to the health care system [3]. The predominant bacterial species associated with CRBSIs are Staphylococcus aureus, S. epidermidis, Pseudomonas aeruginosa, Acinetobacter spp and Bacillus spp [1, 4]. Bacteria causing CRBSIs are derived from the patient’s own skin or from health care staff [5, 6]. When present on the skin, these bacteria do not normally cause serious disease. When the skin is breached, such as by the insertion of a PIVC, they can traverse this barrier and establish a systemic infection [1, 6]. Patients in hospital may be immunocompromised, inhibiting their capacity to combat such infections [7]

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