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. 2019 May 17:14:Doc05.
doi: 10.3205/dgkh000321. eCollection 2019.

Bacterial contamination of automated MRI contrast injectors in clinical routine

Juliane Goebel  1 , Joerg Steinmann  2   3 , Evelyn Heintschel von Heinegg  3 , Tobias Hestermann  1 , Kai Nassenstein  1
Affiliations

Bacterial contamination of automated MRI contrast injectors in clinical routine

Juliane Goebel et al. GMS Hyg Infect Control. .

Abstract
in English, German

Aim: To quantify the frequency of bacterial contamination of the injected contrast agent/saline solution by an automated contrast injection system, and to evaluate whether usage of a novel tube system can reduce it. Methods: For bacterial contamination quantification two identical automated piston pump MRI contrast injectors were used in combination with a standard tube system. 3-5 ml of the contrast agent/saline solution was collected from the system prior to its connection to the patients' venous cannula in 104 consecutive patients. To test, whether a novel tube system reduces contamination, a tube system with shielded screw connections was used with the same contrast injectors and contrast agent/saline samples were collected in further 101 patients. Specimens were microbiologically analyzed. Frequencies of contamination were compared using Fisher exact test. Results: With the standard tube system, bacterial contamination was observed in 5.8% (6 out of 104 specimens). With the novel tube system, contamination was observed in 2.0% (2 out of 101 specimens, p=0.280). Staphylococcus epidermidis was the most common germ (5 cases) followed by Micrococcus luteus (2 cases) and Oligella ureolytica (1 case). Conclusion: Bacterial contaminations of MRI contrast injectors occurred in a non-negligible frequency especially with S. epidermidis. A trend towards reduced bacterial contamination was seen when a novel tube system with shielded screw connections was used.

Ziel: Es sollte die Häufigkeit der bakteriellen Verunreinigung des injizierten Kontrastmittel-/Kochsalzgemisches in der klinischen MRT-Routine erfasst und untersucht werden, ob selbige durch Verwendung eines optimierten Kontrastmittelinjektorsystems reduziert werden kann.Methoden: Es wurde ein automatisches Kolbenpumpen-Kontrastmittelinjektorsystem kombiniert mit einem Standard MRT-Infusionsschlauchsystem verwendet und vor der Ankopplung an die venöse Verweilkanüle von 104 konsekutiven Patienten 3–5 ml des Kontrastmittel-/Kochsalzgemisches entnommen. Zudem wurde bei weiteren 101 Patienten ein optimiertes Infusionsschlauchsystem mit versenkten Schraubenkontakten verwendet und ebenfalls 3–5 ml des Kontrastmittel-/Kochsalzgemisches gesammelt. Die Proben wurden mikrobiologisch analysiert und die Kontaminationshäufigkeit mittels Fisher’s Exact Test verglichen.Ergebnisse: Beim Standard-Infusionsschlauchsystem fand sich in 5,8% (6 von 104 Proben) und beim optimierten Infusionsschlauchsystem in 2,0% (2 von 101 Proben) eine bakterielle Verunreinigung (p=0.280). Am häufigsten war Staphylococcus epidermidis anzüchtbar (n=5), seltener Micrococcus luteus (n=2) und Oligella ureolytica (n=1).Schlussfolgerungen: Eine bakterielle Kontamination des Kontrastmittelinjektorsystems, speziell mit Staphylococcus epidermidis trat in nicht unerheblicher Frequenz auf und konnte durch die Verwendung eines optimierten Infusionsschlauchsystems tendenziell gesenkt werden.

Keywords: MR imaging; automated contrast injector; bacterial contamination; contrast agent; hygiene.

PubMed Disclaimer

Conflict of interest statement

The authors declare that they have no competing interests.

Figures

Table 1
Table 1. Time to positivity of all samples with microbial growth
Figure 1
Figure 1. MRI tube systems
Standard tube system (a) composed of a syringe for contrast media, a syringe for saline solution, a T-shaped connector tube with re-filling lines, a spiral infusion line, and the patient line. Novel tube system (b, d) composed of a syringe for contrast media, a syringe for saline solution (similar to a), a fluid transfer set for re-filling, a T-shaped connector tube, and a spiral patient line with shielded screw connectors (c; b #). Check walves within the tube system are marked by an asterisk (*).
Figure 2
Figure 2. Frequency of bacterial contamination of both MR tube systems
See this image and copyright information in PMC

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