Related Experiment Video
Updated: Jul 19, 2026

A Reference Broth Microdilution Method for Dalbavancin In Vitro Susceptibility Testing of Bacteria that Grow Aerobically
Published on: September 9, 2015
Microbiologic quality assurance for intravenous admixtures in a small hospital
Abstract:
A simple, inexpensive method for end-product testing of intravenous admixtures for microbial contamination was developed and tested by challenging the system with low levels of microbial contamination. The 16-step procedure for testing i.v. admixtures for microbial contamination used total-sample membrane filtration A 0.2-micrometers Nalgene filter unit was used; the entire contents of randomly selected admixtures were to be filtered and discarded under the procedure. Filters were incubated on sheep-blood agar plates for 48 hours at 35 degrees C. Low concentrations (Klebsiella pneumoniae and Pseudomonas aeruginosa were used to contaminate admixtures deliberately to challenge the system. Seventy-two solutions were contaminated with each microbe; 72 other solutions were inoculated with sterile 0.9% sodium chloride; and 72 uninoculated solutions served as controls. Filtration was performed on a laboratory bench to prevent contamination of the laminar-flow hood. In deliberately contaminated solutions, a mean of 82% of inoculated organisms was isolated by membrane filtration. Five instances of adventitious contamination were noted among the 288 samples; these occurred across all experimental groups. Cost per sample was $4-5. This system can be used by hospital pharmacists to produce documentation of quality assurance that will be acceptable in terms of cost, simplicity, and accuracy.
Insights
A new, cost-effective method for testing intravenous (IV) admixtures for microbial contamination was developed. This simple membrane filtration technique accurately detects low-level contamination, ensuring IV product safety.
Area of Science:
- Microbiology
- Pharmaceutical Science
- Quality Control
Background:
- Microbial contamination of intravenous (IV) admixtures poses a significant risk to patient safety.
- Existing methods for end-product testing can be costly and complex.
- Hospital pharmacists require simple, reliable methods for quality assurance.
Purpose of the Study:
- To develop and validate a simple, inexpensive method for end-product testing of IV admixtures for microbial contamination.
- To assess the accuracy and cost-effectiveness of the developed method.
- To provide hospital pharmacists with a practical quality assurance tool.
Main Methods:
- A 16-step total-sample membrane filtration procedure using a 0.2-micrometer filter unit was established.
- Intravenous admixtures were deliberately contaminated with low concentrations of Klebsiella pneumoniae and Pseudomonas aeruginosa.
- Filtration was performed on a laboratory bench, and filters were incubated on sheep-blood agar.
- Control groups included sterile saline inoculations and uninoculated solutions.
Main Results:
- The membrane filtration method successfully isolated a mean of 82% of deliberately inoculated organisms.
- Five instances of adventitious contamination were observed across all 288 samples.
- The cost per sample was determined to be between $4 and $5.
Conclusions:
- The developed membrane filtration method is a simple, accurate, and cost-effective approach for end-product testing of IV admixtures.
- This method provides hospital pharmacists with a viable tool for quality assurance and documentation.
- The system effectively detects low levels of microbial contamination, enhancing patient safety.
Related Concept Videos
Pharmaceutical Alternatives: Stability-Related Therapeutic Nonequivalence
Dosage Interval and Administration Route: Determination Methods
Automated Microbial Diagnostics

