COSMOS Study Microbiological Results: Bacterial Colonization and Infection of Long-Term Peripheral CathetersJuan Luis González López1, Paloma Ruiz Hernández1 and Kenneth W Strauss2*
- *Corresponding Author:
- Ken Strauss
Global Medical Director, BD, Director of Safety in Medicine
European Medical Association, Brussels, Belgium
E-mail: [email protected]
Received Date: March 05, 2014; Accepted Date: April 25, 2014; Published Date: April 28, 2014
Citation: López JLG, Hernández PR, Strauss KW (2014) COSMOS Study Microbiological Results: Bacterial Colonization and Infection of Long-Term Peripheral Catheters. Clin Microbial 3:144. doi: 10.4172/2327-5073.1000144
Copyright: © 2014 López JLG, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Background: Peripheral venous catheters (PVC) have a lower risk of the infection than central venous catheters (CVC), however, their high frequency of use makes PVC a major problem. Nowadays, there is no consensus regarding the diagnosis of PVC infections and current recommendations are not only utopian but can lead to an underestimation of infection rates.
Objectives: To compare the incidence of bacterial colonization and CRI. To identify the significant bacterial colonization in CRI, as well as the main pathogens causing bacterial colonization and CRI in long-term PVC.
Material and methods: Nurse-driven, randomized controlled trial to compare closed system (COS) versus open system (MOS), where catheters were removal only by clinical-indication and were inserted and maintained in accordance with CDC guidelines, except those that apply to routine replacement recommendations. The blinded Maki’s semiquantitative culture technique was used. ClinicalTrials.gov (NCT00665886).
Results: A total of 1183 catheters (631 patients) were randomized, 584 in the COS group (54,173 catheter-hours recorded), and 599 in the MOS group (50,296). 283 PVC were cultured, i.e. 24% of the sample. The mean in-dwell time to onset of event of COS was 239.5 hours compared to 171.9 with MOS. No significant difference in cumulative incidence or incidence density rates per 1000 catheter-days for bacterial colonization, and no statistical significance were found between rates of CRI (COS, 2.2%; MOS, 2.5%). However, we observed a 22% relative risk reduction (RRR) in CRI with COS. Of the 283 cultures, 21.9% were positive, of which the 46.8% were in COS and 53.2% in MOS. There were no significant differences between microorganisms isolated, number of colonies or type of germ. Staphylococcus was responsible for 80.3% of the colonization, and 85.7% of CRI. S. epidermidis was responsible for 48.8% of colonization and 52.4% of CRI. S. aureus was isolated in two cases (9.5%), one in each group.
Discussion: As in previous studies, despite a reduction in the incidence of CRI in closed system, the difference did not reach statistical significance. Nine CRI registered in COS were caused by Gram + (100%), while in MOS 9 CRI were recorded by Gram + (75%), 2 by Gram - (16.7%) and one by Candida (8.3%). Our data seems to confirm that bacteria isolated from closed systems are less virulent and/or that these systems may offer protection against CRI.
Conclusion: International guidelines for best clinical practice should differentiate CRI from CRBSI in the management of peripheral lines-related infections. No statistical differences exist between rates of CRI. However, there is a RRR of CRI with closed systems. A total of 29% of the catheter cultured were associated with CRI (26.5% in COS, 31.3% in MOS), suggesting less virulence of the bacteria isolated in closed systems or greater protection offered by such systems. In long-term PVC, staphylococci causes 80% of colonizations, and 100% of CRI in closed systems and while only 75% in open. There were no significant differences between isolated bacteria, the number of colonies or the type of pathogen.