Published on September 17, 2020 By Dr. Chandra Shekar P.  - Head - Genetic Toxicology & Microbiology

Medical Devices like Needle free Intravenous and Intravascular Administration sets as well as Single-use systems (SUSs) used for biopharmaceutical manufacturing must maintain sterility. The microbial barrier properties of these devices and SUSs should demonstrate the microbial integrity and should be validated as providing an effective barrier against microbial ingress. These Medical devices are prone for the microbial ingress because of repeated use or product failure or possibly, product misuse. The microbial ingress put patient’s at high risk of infection. 

These risks will be evaluated using Microbial Ingress Test to ensure the effective disinfection of medical device as well as the injection site.  

This study was conducted to assess the microbial ingress (prevent entry of microorganisms) activity of Needle Free Injection Stoppers, following FDA guidance document - "Guidance for Industry and FDA staff, Intravascular Administration sets premarket Notification Submission [510(k)], July 11, 2008, section 8: Microbial ingress testing". 

Scope/Recommended Devices: 

Intravenous (IV) Set Stopcock,  Intravascular Administration Set, Blood Transfusion Set Infusion Line Filter, Blood Transfusion Microfilter, Fluid Delivery Tubing, IV fluid Transfer Set.   

Test Organisms: 

Gram (+) Strains: Staphylococcus aureus (ATCC#6538), Staphylococcus epidermidis (ATCC#12228) 

Gram (-) Strains: E.coli (ATCC#8739), Klebsiella pneumoniae (ATCC#4352) 

Source: American Type Culture Collection (ATCC), USA 

Test Procedure: 

Device Contamination/inoculation: Microbial challenge by immersion test method   

Test devices were contaminated with challenge organisms by immersion method, for a period of 30 minutes. Post incubation, test devices were disinfected externally at syringe connector point and activated with needle free syringe filled with sterile normal saline. Following flush off, saline solution was collected and CFU counts were estimated by membrane filtration technique. Same procedure was followed for 10 days, one activation per day.
   

End Points: 

Results & Evaluation:

Microbial recovery study:

Test device microbial recovery plates showed a good number of colony counts and the observed microbial recovery was >70%.   

Microbial ingress study: 

• Negative Control:
  • No growth was observed in all the negative control plates, indicates all the media, reagents and disposables used for the study were sterile and study procedure conducted under sterile conditions.   
• Positive Control:  
  • Growth was observed in all the positive control plates, indicates effectiveness of 70% Isopropyl Alcohol swabbing procedure. 
• Test device:  
  • All the test devices showed effective microbial barrier function.