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Higher chlorhexidine gluconate concentrations more effective for elimination of MRSA in PJI model
Results from an in vitro periprosthetic joint infection model indicated higher concentrations of a chlorhexidine gluconate solution were better than lower concentrations to eliminate biofilm, with the greatest efficacy seen with concentrations of 2%.
Researchers incubated methicillin-resistant Staphylococcus aureus (MRSA) at 37° C overnight after suspension in a trypticase soy broth (TSB) liquid culture. Bacteria were treated with 3 mL of TSB, placed into titanium-alloy disks and put into six well-plates to grow biofilms. Biofilm was verified with gylcocalyx matrix development.
The investigators categorized the disks into six groups (A through F), with group A serving as the control of saline pulse irrigation and saline scrub. After irrigation, groups B through F were scrubbed for 1 minute with a 20 mL solution containing 4%, 2%, 1%, 0.5% and 0.25% of chlorhexidine gluconate (CG), respectively. Researchers conducted colony counts to evaluate colony forming units (CFUs) and evaluated bacteria growth using a second set of six plates that were reincubated in 3 mL TSB at 37° C.
Results showed group A had the most bacteria growth, and group C (with a 2% CG concentration) had the fewest CFUs. The next fewest CFUs were seen in groups D, E, B and F, respectively. In the reincubation group, results for the most and fewest CFUs still held. Investigators found significantly more CFUs in groups D and F compared with groups B and C, according to the study.
“The observed efficacy of 2% solution and the decrease in the bacteria kill rate transitioning from 2% to 1% make 2% the most advantageous concentration to balance antimicrobial effect with minimal potential side effects,” the authors wrote. ‒ by Monica Jaramillo
Disclosures: Smith reports no relevant financial disclosures. Please see the full study for a list of all other authors’ relevant financial disclosures.