Investigation of the effects of antimicrobial and anti-biofilm peptide IDR1018 and chitosan nanoparticles on ciprofloxacin-resistant Escherichia coli.

Peptide IDR1018 and chitosan nanoparticles (CNs) showed antimicrobial and anti-biofilm activity against bacteria. In this study, the antimicrobial effects of peptide IDR1018 and CNs were evaluated on 50 clinical isolates of uropathogenic Escherichia coli (UPEC) resistant to ciprofloxacin. Ion gelation method was applied for CNs synthesis. Scanning electron microscope (SEM) and dynamic light scattering (DLS) were utilized to evaluate the nanoparticles. Antimicrobial and synergistic activity of peptide IDR1018 and CNs with ciprofloxacin were evaluated by microtiter broth dilution method. The checkerboard test was used to investigate the antimicrobial effects of IDR1018 and CNS in combination with ciprofloxacin. Anti-biofilm effect of ciprofloxacin, peptide IDR1018, and CNs was evaluated using crystal violet method. Fourteen (28%), 21 (42%), and 15 (30%) of clinical isolates produced strong, moderate, and weak biofilm, respectively. The CNs were spherical and uniform under electron microscopy with an average diameter of 246 nm. The minimum inhibitory concentration (MIC) values were 16-128, 20-40, and 375-750 (µg/ml) for ciprofloxacin, peptide IDR1018, and CNs, respectively. Fractional inhibitory concentration (FIC) analysis indicated a synergistic effect of ciprofloxacin in combination with peptide IDR1018, but in combination with CNs, this antibiotic showed an additive effect. Our results revealed that peptide IDR1018 and CNs have antimicrobial properties on UPEC isolates. Biofilm inhibition and biofilm eradication of clinical isolate were shown by peptide IDR1018 and CNs in a concentration-dependent manner. The antimicrobial agents alone and in combination decreased the number of viable bacteria in the biofilms. Therefore, these components seem to be a treating approach against biofilm-forming UPEC isolates.

Determination of COVID-19 prevalence with regards to age range of patients referring to the hospitals located in western Tehran, Iran.

We decided to examine suspected samples of pneumonia outbreak caused by the new coronavirus SARS-CoV-2 and provide information about the mortality rate due to this infection in different age groups in Iran. In this descriptive-cross-sectional study, a total of 784 samples of naso/oropharyngeal swabs of suspected patients with COVID-19 symptoms who had referred to Imam Khomeini, Shahid Fayaz-Bakhsh and Modarres hospitals in Tehran from February 24, 2020 to March 24, 2020 were examined by RT-PCR method. The highest incidence of the disease was within the age group of 50-59 years, while the lowest rate was in the 0-9 years age group. The highest rate of positive samples in terms of COVID-19 among suspected individuals was for patients >80 years of age (89%) and the highest mortality rate was in the age range of 70-79 years (31%) and >80 years (30), respectively. In terms of recovery, the highest rate was in the 30-39 years age group (65.2%). Statistical analysis showed that mortality significantly increased in the age group of >60 years old and in fact, mortality was significantly associated with older ages. According to the results of the current study, the prevalence of COVID-19 in lower age (0-9 years old) is lower and mortality rate is higher in older ages as significant increase in mortality was observed in those aged >60 years old. However, further epidemiological studies on a larger study population in different regions of Iran are needed to explain the prevalence, clinical features, and course of the disease.