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Methicillin-resistant Staphylococcus aureus is the cause of nosocomial and community-acquired infections. This study aimed to evaluate the effect of zinc oxide and silver nanoparticles (ZnO-Ag NPs) on biofilms formation and icaA gene expression in methicillin-resistant S. aureus (MRSA). In this study, three standard strains (ATCC 43300, 25923, and 29913) and a clinical isolate are included. The minimum inhibitory concentration (MIC) of nanoparticles was determined by microdilution broth method. The antibacterial effects of ZnO-Ag NPs either alone or in combination with each other were compared with vancomycin (as the control group). The effect of MIC and sub-MIC concentrations of ZnO-Ag NPs on biofilm formation was determined by the microtiter plate method. The expression level of the icaA gene was assessed by real-time PCR LightCycler® 96 software (Version 1.1.0.1320, Roche, Germany). technique. All experiments were repeated three times. Data were analyzed using SPSS software through ANOVA and t-test. The P-value of less than .05 was considered as statistically significant. The average MICs of ZnO, Ag, and ZnO-Ag NPs compounds were 393.2, 179.8, and 60.8 μg/ml, respectively. The compound of ZnO-Ag NPs had a synergistic effect against all isolates. ZnO-Ag NPs decreased the biofilm formation rate at MIC and sub-MIC concentrations (P < .001). Sub-MIC ZnO-Ag NPs concentration significantly reduced the icaA gene expression in S. aureus strains (P < .03). The sub-MIC concentration of ZnO-Ag NPs reduced biofilm formation rate and icaA gene expression in Staphylococcus aureus strains compared with vancomycin. It can be used to cover medical devices after examining more clinical isolates to prevent bacterial colonization.

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Background: Urinary tract infection (UTI) is a major complication in patients who receive the kidney transplant. We aimed to evaluate the prevalence and antimicrobial resistance of bacterial uropathogens isolated from Iranian kidney transplant recipients. Methods: We searched according to Prisma protocol for UTI infection, prevalence, occurrence and distribution of bacteria and their pattern of antibiotic resistance among Iranian patients who receive kidney transplant through online electronic databases with MeSh terms and text words in published references in both Persian and English languages during 1990-2017. Data analysis was performed using Comprehensive meta-analysis software (CMA) by Cochrane Q and I2 Random Effects Model. Results: Eleven studies met the eligible inclusion criteria. The prevalence of UTI among kidney transplant patients varied from 11.7% to 67.5%. The combined prevalence of UTI was 32.6%. Among Gram-negative pathogens causing UTI, E. coli was the most dominant followed by Klebsiella pneumonia with prevalence 41.3% and 11.9%, respectively. Also, amongst Gram-positive bacteria, the highest prevalence belonged to Enterococcus spp. (9.8%) and coagulase-negative Staphylococci (9.4%). Also in Gram-negative pathogens, the most resistance was to ampicillin (91.2%), followed by ceftazidime (89.5%). The minimum resistance was against imipenem with prevalence 14.3%. Conclusion: The combined prevalence of UTI was 32.6%. Gram-negative pathogens especially E. coli were the most agents of UTI in Iranian patients who receive kidney transplant. Also, in gram-negative pathogens, the most resistance was to ampicillin that it needs a new strategy for prophylaxis and treatment of UTI after the kidney transplant.