Bactericidal Activity of N -Chlorotaurine against Biofilm-Forming Bacteria Grown on Metal Disks

Abstract

Many orthopedic surgeons consider surgical irrigation and debridement with prosthesis retention as a treatment option for postoperative infections. Usually, saline solution with no added antimicrobial agent is used for irrigation. We investigated the activity of N-chlorotaurine (NCT) against various biofilm-forming bacteria in vitro and thereby gained significant information on its usability as a soluble and well-tolerated active chlorine compound in orthopedic surgery. Biofilms of Staphylococcus aureus were grown on metal alloy disks and in polystyrene dishes for 48 h. Subsequently, they were incubated for 15 min to 7 h in buffered solutions containing therapeutically applicable concentrations of NCT (1%, 0.5%, and 0.1%; 5.5 to 55 mM) at 37°C. NCT inactivated the biofilm in a time-and dose-dependent manner. Scanning electron microscopy revealed disturbance of the biofilm architecture by rupture of the extracellular matrix. Assays with reduction of carboxanilide (XTT) showed inhibition of the metabolism of the bacteria in biofilms. Quantitative cultures confirmed killing of S. aureus, Staphylococcus epidermidis, and Pseudomonas aeruginosa biofilms on metal alloy disks by NCT. Clinical isolates were slightly more resistant than ATCC type strains, but counts of CFU were reduced at least 10-fold by 1% NCT within 15 min in all cases. NCT showed microbicidal activity against various bacterial strains in biofilms. Whether this can be transferred to the clinical situation should be the aim of future studies.

Biofilm formation on titanium implants counteracted by grafting gallium and silver ions

“…In two very recent in vitro studies, dealing with the detachment of bacterial biofilms from disks, either by fluid for oral rinses or by solutions of N ‐chlorotaurine for surgical irrigations, the antimicrobial/antibiofilm effects were evaluated by the XTT assay for bacterial metabolic activity, by live/dead staining, as well as by CFU counting . Live/dead staining did not apply to our in vivo study, since after 24‐h of oral application of the disks, besides bacteria, also epithelial cells exfoliating from the mouth mucosae could have adhered onto the disks, thus altering the results.…”

N-Chlorotaurine, a Promising Future Candidate for Topical Therapy of Fungal Infections

“…In a first study using 300 µM NCT, the development of Pseudomonas aeruginosa biofilm could be inhibited in microtitre plates in vitro [ 46 ]. In two following studies using millimolar application concentrations of NCT, bactericidal activity was found against biofilms of S. aureus , Staphylococcus epidermidis , and P. aeruginosa on alloy disks [ 47 , 48 ].…”

Bactericidal and Fungicidal Activity of N -Chlorotaurine Is Enhanced in Cystic Fibrosis Sputum Medium

“…As an active chlorine compound, it is microbicidal against bacteria, fungi, viruses, and protozoa, and it does not induce resistance because of the multiple target molecules in pathogens (18,24); this has been confirmed for NCT and its analogue dichlorodimethyltaurine in multiple-passage studies with bacteria (25,26). NCT is also effective against bacteria in biofilms (27)(28)(29).…”