Combined effects of the exposure to silver nanoparticles and noise on hearing function and cochlea structure of the male rats.

AIMS: This study intended to investigate whether exposure to the combination of noise and Ag-NPs in rats induces cochlear damage and hearing dysfunction. MAIN METHODS: A total of 24Wistar rats were divided into four treatment groups and received/exposed to saline (IP), Ag-NPs (100 mg/kg, 5d/w for 4 weeks), 8 kHz narrowband noise (104 dB SPL, 6 h/day, 5d/w for 4 weeks) and Ag-NPs plus noise. The DPOAE, serum levels of MDA and SOD and changes in body weight were assessed. The rat cochlea was further stained for investigating the mRNA expression (TL-6, NOX3, and TNF-), IHC (TUJ-1 and MHC7), and histological alterations. The Ag-NPs characteristics were also analysed by SEM and XRD. KEY FINDINGS: DPOAE values were remarkably reduced (p < 0.05) among the exposed groups. Furthermore, exposure to noise and Ag-NPs significantly increased MDA levels and decreased the SOD activity in the serum. In comparison to the control group, the expression of IL-6, TNF-, and NOX3 was shown to be elevated in the Ag-NPs plus noise group. The body weight also increased significantly in all groups with the exception of the Ag-NPs plus noise group. IHC tests showed remarkable down-regulation of TUJ1 and MYO7A. Morphological changes confirmed our findings as well. SEM and XRD data validated the production of Ag-NPs. SIGNIFICANCE: According to the findings of this study, sub-acute exposure to noise and Ag-NPs causes permanent damage to the hair cells that are in charge of high-frequency perception.

Rapid identification of Iranian Acinetobacter baumannii strains by single PCR assay using BLA oxa-51 -like carbapenemase and evaluation of the antimicrobial resistance profiles of the isolates.

The rapid identification of relevant bacterial pathogens is of utmost importance in clinical settings. The aim of this study was to test a rapid identification technique for A. baumannii strains from Tehran Hospitals and to determine the antibiotic resistance profiles of the isolates. A hundred strains of Acinetobacter spp. grown from clinical specimens were identified as A. baumannii by conventional methods. Using PCR a bla OXA-51 -like gene was detected in all A. baumannii isolates but not in other species of acinetobacter. More than half of the isolates proved resistant to a variety of antibiotics by the disk diffusion technique. The rate of resistance to gentamicin, imipenem, ampicillin-sulbactam and amikacin was determined to be 45%, 53%, 62% and 62%, respectively. Moreover, most isolates (more than 90%) showed resistance to cephalosporins. This study shows that the demonstration of the bla OXA-51-like gene is a reliable and rapid way for the presumptive identification of A. baumannii and reveals that the rate of antibiotic resistance is high in Iranian A. baumannii isolates to a variety of antibiotics.