Molecular investigation of bacterial communities on the inner and outer surfaces of peripheral venous catheters.

Peripheral venous catheters (PVCs) are some of the most widely used medical devices in hospitals worldwide. PVC-related infections increase morbidity and treatment costs. The inner surfaces of PVCs are rarely examined for the population structure of bacteria, as it is generally believed that bacteria at this niche are similar to those on the external surface of PVCs. We primarily test this hypothesis and also study the effect of antibiotic treatment on bacterial communities from PVC surfaces. The inner and outer surfaces of PVCs from 15 patients were examined by 454 GS FLX Titanium 16S rRNA sequencing and the culture method. None of the PVCs were colonised according to the culture method and none of the patients had a bacteraemia. From a total of 127,536 high-quality sequence reads, 14 bacterial phyla and 268 diverse bacterial genera were detected. The number of operational taxonomic units for each sample was in the range of 86-157, even though 60 % of patients had received antibiotic treatment. Stenotrophomonas maltophilia was the predominant bacterial species in all the examined PVC samples. There were noticeable but not statistically significant differences between the inner and outer surfaces of PVCs in terms of the distribution of the taxonomic groups. In addition, the bacterial communities on PVCs from antibiotic-treated patients were significantly different from untreated patients. In conclusion, the surfaces of PVCs display complex bacterial communities. Although their significance has yet to be determined, these findings alter our perception of PVC-related infections.

Assessment of peripheral arterial catheters as a source of sepsis in the critically ill: a narrative review.

Intravascular devices (IVDs) are essential in the management of critically ill patients; however, IVD-related sepsis remains a major complication. Arterial catheters (ACs) are one of the most manipulated IVDs in critically ill patients. When bloodstream infection (BSI) is suspected in a patient with an IVD in situ, clinicians have focused their attention on the central venous catheter (CVC) while largely ignoring the AC. Although it would be routine for the CVC to be cultured and replaced if necessary for suspected IVD or catheter-related sepsis, the AC may not be treated in the same manner. The reasons for this may in part relate to the patient groups studied. In lower acuity patients with short dwell times, AC sepsis rates are indeed low. In the higher acuity patient, earlier studies suggested that ACs had an infective potential at least equal to short term CVCs, a finding that has translated poorly into clinical practice. It has been estimated that there may be up to 48,000 BSIs per year arising from ACs in the USA alone, suggesting a significant clinical problem. Recent evidence now shows that the infective potential of the AC is comparable with that in short term CVCs regarding both colonisation (which precedes BSI) and BSI, consolidating earlier studies. In critically ill patients suspected of catheter-related bloodsteam infection it is suggested that both the AC and CVC must now be assessed together.