Prevalence of the ica operon and insertion sequence IS256 among Staphylococcus epidermidis prosthetic joint infection isolates

Abstract

Joint replacement surgery has improved the quality of life for hundreds of thousands of patients. However, the infection of a joint implant is an important and serious complication, though the prevalence is low. Staphylococcus epidermidis is the most important pathogen involved in foreign-body infections. S. epidermidis is also a commensal that comprises a substantial part of the normal skin flora of humans. The possibility to demonstrate potential specific virulence markers may facilitate the interpretation of the bacteriological findings, as well as the clinical decision. The prevalence of the ica locus and insertion sequence IS256 by using polymerase chain reaction (PCR) among 32 clinical S. epidermidis isolates from prosthetic joint infections (PJIs) and 24 commensal isolates from nares and skin was investigated. Sixteen (50%) of the 32 PJI isolates harbored the ica operon compared with one-third of the commensal isolates obtained from the samples of the skin and nares of healthy individuals. The IS256 was demonstrated in 26 (81%) out of 32 PJI isolates. By contrast, IS256 was found in one of 24 commensal isolates. In conclusion, IS256 may be superior to the ica operon as a marker of the invasive capacity of S. epidermidis, since it was found in most of the PJI isolates, but rarely among commensals.

Biofilm Producing Staphylococcus epidermidis Strains Isolated From Clinical Samples in Tehran, Iran

“…The presence of IS256 transposon in ica locus has been reported previously (10,11,40). Results of the present study is unlike that of Conlon et al (41), which revealed that integration of IS256 to ica locus decreased the ability of strains to form biofilms.…”

Transferable Plasmid-Mediated Resistance to Linezolid Due to cfr in a Human Clinical Isolate of Enterococcus faecalis

“…2, we found two imperfect IRs flanking cfr in E. faecalis 603-50427X, suggesting that the gene may also be transferable via IS256-mediated transposition. Of note, this insertion sequence has been associated with aminoglycoside resistance (29,42) and with the ica operon in biofilm producers of Staphylococcus epidermidis (28,29). Since a high prevalence of transposons with IS256 sequences in enterococcal isolates has been reported from Japan and Thailand (70,32) and many cfr-carrying strains have been detected in the last 2 years in China (13,33,68,69,72), it is tempting to speculate that cfr has an important potential for dissemination from animals to humans in Southeast Asia.…”

Quaternized Chitosan Inhibits icaA Transcription and Biofilm Formation by Staphylococcus on a Titanium Surface

“…Bacterial adherence to orthopedic implant surfaces occurs in two essential steps (29). Its adherence to the implanted surface is followed by an accumulation process and the production of extracellular substances, such as polysaccharide intercellular adhesin (PIA) (28,47). The production of PIA is mediated by the intercellular adhesin (ica) locus, which comprises four core genes (icaA, icaB, icaC, and icaD) and a regulatory gene (icaR) (2,19,24).…”