Biofilm formation by Staphylococcus pseudintermedius on titanium implants

Abstract

Osteomyelitis often involves Staphylococcus spp. as the isolated genus in domestic animal cases. Implant-related infections, frequently associated with biofilm-forming microorganisms like staphylococci species, necessitate careful material selection. This study assessed biofilm formation by Staphylococcus pseudintermedius on titanium nuts used in veterinary orthopaedic surgery. Biofilm quantification employed safranin staining and spectrophotometric measurement, while bacterial counts were determined in colony-forming units (CFU). Scanning Electron Microscopy (SEM) evaluated the biofilm morphology on the surface of titanium nuts. All samples had CFU counts. Absorbance values that evidence biofilm formation were observed in seven of the eight samples tested. SEM images revealed robust bacterial colonization, and significant extracellular polymeric substance production, and the negative control displayed surface irregularities on the nut. Whole genome sequencing revealed accessory Gene Regulator (agr) type III in six samples, agr IV and agr II in two each. Genes encoding hlb, luk-S, luk-F, siet, se_int, and the icaADCB operon were identified in all sequenced samples. Other exfoliative toxins were absent. Biofilm formation by S. pseudintermedius was detected in all samples, indicating the susceptibility of orthopaedic titanium alloys to adhesion and biofilm formation by veterinary species. The biofilm formation capacity raises concerns about potential post-surgical complications and associated costs.