Staphopain mediated virulence and antibiotic resistance alteration in co-infection of Staphylococcus aureus and Pseudomonas aeruginosa: an animal model.

Polymicrobial communities lead to worsen the wound infections, due to mixed biofilms, increased antibiotic resistance, and altered virulence production. Promising approaches, including enzymes, may overcome the complicated condition of polymicrobial infections. Therefore, this study aimed to investigate Staphopain A-mediated virulence and resistance alteration in an animal model of Staphylococcus aureus and Pseudomonas aeruginosa co-infection. S. aureus and P. aeruginosa were co-cultured on the L-929 cell line and wound infection in an animal model. Then, recombinant staphopain A was purified and used to treat mono- and co-infections. Following the treatment, changes in virulence factors and resistance were investigated through phenotypic methods and RT-PCR. Staphopain A resulted in a notable reduction in the viability of S. aureus and P. aeruginosa. The biofilm formed in the wound infection in both animal model and cell culture was disrupted remarkably. Moreover, the biofilm-encoding genes, quorum sensing regulating genes, and virulence factors (hemolysin and pyocyanin) controlled by QS were down-regulated in both microorganisms. Furthermore, the resistance to vancomycin and doripenem decreased following treatment with staphopain A. According to this study, staphopain A might promote wound healing and cure co-infection. It seems to be a promising agent to combine with antibiotics to overcome hard-to-cure infections.

Molecular epidemiology and collaboration of siderophore-based iron acquisition with surface adhesion in hypervirulent Pseudomonas aeruginosa isolates from wound infections.

Iron/siderophore uptake may play an important role in the biofilm formation and secretion of extracellular proteins in Pseudomonas aeruginosa isolates. In the present study, the role of siderophores, heme, and iron regulatory genes in the virulence of Pseudomonas aeruginosa isolates collected from wound infection was investigated. Three hundred eighty-four (384) swab samples were collected from wound infection and identified by phenotypic methods. The quantitative real-time PCR (qRT-PCR) method was evaluated for the gene expressions study. Multi-locus sequence typing (MLST) was used to screen unique sequence types (ST) and clonal complexes (CC). Fifty-five (55) P. aeruginosa isolates were detected in all swab samples. Also, 38 (69.1%) isolates formed biofilm. The prevalence of virulence factor genes was as follows: plcN (67.2%), exoY (70.9%), exoA (60.0%), phzM (58.1%), plcH (50.9%), lasB (36.3%), aprA (69.1%), lasA (34.5%), nanI (74.5%), exoU (70.9%), exoS (60.0%), exoT (63.6%) and algD (65.4%). According to qRT-PCR, genes regulating iron uptake were highly expressed in the toxigenic isolate. The highest expressions levels were observed for hemO, hasR, and pvdA genes in the biofilm-forming isolates. The MLST data confirmed a high prevalence of ST1, ST111, and ST235, with six, five, and 12 clusters, respectively. ST235 and ST1 were the most present among the biofilm-forming and toxigenic strains. Also, the nuoD gene with 54 and guaA with 19 showed the highest and lowest number of unique alleles. We demonstrated that iron/siderophore uptake is sufficient for biofilm formation and an increase in the pathogenesis of P. aeruginosa. These results suggest that the iron/siderophore uptake system may alter the MLST types of P. aeruginosa and predispose to bacterial pathogenesis in wound infections.

Antibiotic resistance alters through iron-regulating Sigma factors during the interaction of Staphylococcus aureus and Pseudomonas aeruginosa.

Iron is a limiting factor in such a condition that usually is sequestered by the host during polymicrobial infections of Pseudomonas aeruginosa and Staphylococcus aureus. This study aimed to investigate the interaction of S. aureus and P. aeruginosa, which alters iron-related sigma factors regulation and antibiotic resistance. The antibiotic resistance of P. aeruginosa and S. aureus was investigated in a L929 cell culture model. The expression level of pvdS, hasI (P. aeruginosa sigma factors), and sigS (S. aureus sigma factor) genes was determined using Quantitative Real-Time PCR. pvdS and hasI were downregulated during co-culture with S. aureus, while the susceptibility to carbapenems increased (p-value < 0.0001). Also, there was a direct significant relationship between resistance to vancomycin with sigS. Regarding the findings of the current study, iron-related sigma factors of P. aeruginosa and S. aureus play a role in induction susceptibility to various antibiotics, including carbapenems and vancomycin.

A Comprehensive Study of the Relationship between the Production of ß-Lactamase Enzymes and Iron/Siderophore Uptake Regulatory Genes in Clinical Isolates of Acinetobacter baumannii.

BACKGROUND: The iron/siderophore uptake system (IUS) involved in the Acinetobacter baumannii pathogenicity. However, IUS's role in antibiotic resistance and the production of ß-lactamase enzymes of A. baumannii are unclear. This study aimed to investigate the relationship between the production of ß-lactamase enzymes and IUS regulatory genes in clinical isolates of A. baumannii. Methods. A. baumannii isolates were collected from clinical isolates using biochemical tests. The antibiotic resistance patterns and ß-lactamase-producing strains were identified using the disk diffusion method (DDM). Also, IUS genes were detected by the polymerase chain reaction (PCR) method. RESULTS: Seventy-two (72) A. baumannii isolates were collected from a different clinical specimen. Gentamicin-resistant strains (43%) had the highest frequency, and aztreonam-resistant strains (12.5%) had the lowest frequency. Also, the distribution of AmpC and MBL producing isolates were 27.7% and 35%, respectively. Moreover, the frequencies of basD, bauA, pld, paaE, entA, feoB, hemO, and tonB genes were as follows: 12.5%, 15.2%, 11.1%, 15.2%, 19.4%, 16.6%, 23.6%, and 6.9%. Further, a strong correlation was observed between the abundance of ß-lactamase-producing strains and IUS genes. CONCLUSIONS: Based on our knowledge from this study, the association between ß-lactamase production and IUS genes in A. baumannii plays an essential role in the emergence of drug-resistant strains.

Comparing the Success Rate and Side Effects of Endovenous Laser Ablation and Radiofrequency Ablation to Treat Varicose Veins in the Lower Limbs: A Randomized Clinical Trial.

Introduction: Varicosis is a condition affecting the superficial venous system of the lower limbs. Endovenous laser ablation (EVLA) is a minimally invasive method that uses different frequencies of laser for treatment. Radiofrequency (RF) has also been effectively used for vein ablation through thermal mechanisms. This study compares the success rate and side effects of EVLA and RF to treat varicose veins in the lower limbs within 12 months. Methods: In this two-arm, parallel-group, randomized controlled, single-blind study, 1090 patients with lower limb varicosis proven by Doppler ultrasonography (DUS) were randomly placed into one of the two groups: EVLA and RF ablation. In the EVLA group, we used a 980-nm diode laser in a pulse mode and in the RF group, a 7-cm ClosureFast (Covidien, USA) catheter with an RF generator. We assessed pain during the operation and 8 and 24 hours after the surgery by the numerical rating scale (NRS). The patients were followed up on day 7, then 3, 6, and 12 months postoperatively. The presence or absence of pain and then the severity of pain (according to NRS), the recurrence rate, complications, and the length of the procedure were compared. Results: There was no significant difference between the two groups in the patients' characteristics, major adverse events and pain severity during the procedure and 8 and 24 hours after the surgery. According to NRS, the mean chronic pain severity in the EVLA group was 3.99± 0.754 versus 4.50± 0.657 in the RF group, and the difference was not significant. The length of operation and the recurrence rate 12 months after the procedure were not significantly different. Conclusion: The results of our study further establish the efficacy of EVLT and RF ablation for lower limb varicosis treatment without any significant difference in the clinical outcomes and complications during a 12-months follow-up.