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Staphylococcus haemolyticus (S. haemolyticus) is one of the Coagulase-negative staphylococci (CoNS) that inhabits the skin as a commensal. It is increasingly implicated in opportunistic infections, including diabetic foot ulcer (DFU) infections. In contrast to the abundance of information available for S. aureus and S. epidermidis, little is known about the pathogenicity of S. haemolyticus, despite the increased prevalence of this pathogen in hospitalized patients. We described, for the first time, the pathogenesis of different clinical isolates of S. haemolyticus isolated from DFU on primary human skin fibroblast (PHSF) cells. Virulence-related genes were investigated, adhesion and invasion assays were carried out using Giemsa stain, transmission electron microscopy (TEM), MTT and flowcytometry assays. Our results showed that most S. haemolyticus carried different sets of virulence-related genes. S. haemolyticus adhered to the PHSF cells to variable degrees. TEM showed that the bacteria were engulfed in a zipper-like mechanism into a vacuole inside the cell. Bacterial internalization was confirmed using flowcytometry and achieved high intracellular levels. PHSF cells infected with S.haemolyticus suffered from amarked decrease in viability and increased apoptosis when treated with whole bacterial suspensions or cell-free supernatants but not with heat-treated cells. After co-culture with PBMCs, S. haemolyticus induced high levels of pro-inflammatory cytokines. This study highlights the significant development of S. haemolyticus, which was previously considered a contaminant when detected in cultures of clinical samples. Their high ability to adhere, invade and kill the PHSF cells illustrate the severe damage associated with DFU infections.

Staphylococcus haemolyticus (S. haemolyticus) is one of the Coagulase-negative staphylococci (CoNS) that inhabits the skin as a commensal. It is increasingly implicated in opportunistic infections, including diabetic foot ulcer (DFU) infections. In contrast to the abundance of information available for S. aureus and S. epidermidis, little is known about the pathogenicity of S. haemolyticus, despite the increased prevalence of this pathogen in hospitalized patients. We described, for the first time, the pathogenesis of different clinical isolates of S. haemolyticus isolated from DFU on primary human skin fibroblast (PHSF) cells. Virulence-related genes were investigated, adhesion and invasion assays were carried out using Giemsa stain, transmission electron microscopy (TEM), MTT and flowcytometry assays. Our results showed that most S. haemolyticus carried different sets of virulence-related genes. S. haemolyticus adhered to the PHSF cells to variable degrees. TEM showed that the bacteria were engulfed in a zipper-like mechanism into a vacuole inside the cell. Bacterial internalization was confirmed using flowcytometry and achieved high intracellular levels. PHSF cells infected with S.haemolyticus suffered from amarked decrease in viability and increased apoptosis when treated with whole bacterial suspensions or cell-free supernatants but not with heat-treated cells. After co-culture with PBMCs, S. haemolyticus induced high levels of pro-inflammatory cytokines. This study highlights the significant development of S. haemolyticus, which was previously considered a contaminant when detected in cultures of clinical samples. Their high ability to adhere, invade and kill the PHSF cells illustrate the severe damage associated with DFU infections.

Purpose Our purpose was to compare the efficacy of ‘epithelium-off’ and ‘epithelium-on’ cross-linking (CXL) in treatment of progressive keratoconus. Patients and methods This study included 48 eyes of 26 patients who met our inclusion criteria. The Epi- Off CXL group included 32 eyes of 17 patients, and the Epi-On CXL group included 16 eyes of nine patients. Preoperative assessments of uncorrected and bestcorrected visual acuities, refractive errors, keratometry, and corneal tomography including pachymetry, were compared with the postoperative values. Results Preoperatively, there was a statistically nonsignificant difference between the two groups in all studied variables except for the pachymetry at thinnest location. In the Epi-Off group, there was a significant improvement of uncorrected visual acuity, best-corrected visual acuity, Kmax, and inferior–superior value at the 12-month visit. There was late significant worsening of the back elevation and spherical equivalent at the 12-month visit and also significant thinning of pachymetry at thinnest location associated with significant worsening of the average thickness increase. All other variables showed nonsignificant change (stabilization) at both postoperative visits. In the Epi-On group, there was significant thinning of pachymetry at thinnest location and stabilization of uncorrected corrected visual acuity, best-corrected visual acuity, K1, Kmax, (inferior–superior), Y-coordinate, and front elevation at both postoperative visits, and early stabilization with late worsening of all of other variables. Conclusion The Epi-Off CXL was found to be more superior to Epi-On CXL in terms of stabilization of progressive keratoconus but was inevitably associated with complications related to epithelial debridement.

Purpose Our purpose was to compare the efficacy of ‘epithelium-off’ and ‘epithelium-on’ cross-linking (CXL) in treatment of progressive keratoconus. Patients and methods This study included 48 eyes of 26 patients who met our inclusion criteria. The Epi- Off CXL group included 32 eyes of 17 patients, and the Epi-On CXL group included 16 eyes of nine patients. Preoperative assessments of uncorrected and bestcorrected visual acuities, refractive errors, keratometry, and corneal tomography including pachymetry, were compared with the postoperative values. Results Preoperatively, there was a statistically nonsignificant difference between the two groups in all studied variables except for the pachymetry at thinnest location. In the Epi-Off group, there was a significant improvement of uncorrected visual acuity, best-corrected visual acuity, Kmax, and inferior–superior value at the 12-month visit. There was late significant worsening of the back elevation and spherical equivalent at the 12-month visit and also significant thinning of pachymetry at thinnest location associated with significant worsening of the average thickness increase. All other variables showed nonsignificant change (stabilization) at both postoperative visits. In the Epi-On group, there was significant thinning of pachymetry at thinnest location and stabilization of uncorrected corrected visual acuity, best-corrected visual acuity, K1, Kmax, (inferior–superior), Y-coordinate, and front elevation at both postoperative visits, and early stabilization with late worsening of all of other variables. Conclusion The Epi-Off CXL was found to be more superior to Epi-On CXL in terms of stabilization of progressive keratoconus but was inevitably associated with complications related to epithelial debridement.