mRNA expression of toll-like receptors 3, 7, 8, and 9 in the nasopharyngeal epithelial cells of coronavirus disease 2019 patients.

BACKGROUND: The etiopathogenesis of coronavirus disease 2019 (COVID-19) stem partially from the abnormal activation of the innate and adaptive immune systems. Here in the current investigation, the mRNA expression levels of toll-like receptors (TLRs) were evaluated in the nasopharyngeal epithelial cells from COVID-19 patients. METHODS: Epithelial cells were obtained using nasopharyngeal swab samples from 90 COVID-19 patients and 50 controls. COVID-19 cases were classified into those without symptoms, with symptoms but not hospitalized, and with symptoms and hospitalized. To determine the mRNA expression levels of TLRs, first RNA was extracted and cDNA was synthesized, and finally Real-time PCR was exerted. RESULTS: It was seen that the transcript levels of TLR3, TLR7, TLR8, and TLR9 were overexpressed in the COVID-19 patients with clinical symptoms needing hospitalization as well as in those with clinical symptoms without needing for hospitalization compared to controls. Upregulation of TLRs was associated with clinical presentations of the patients. CONCLUSIONS: Modulation of TLR3, TLR7, TLR8, TLR9 in the epithelial cells of COVID-19 cases may estimate the disease severity and requirement for hospitalization.

Effects of nisin on the expression of virulence genes of methicillin-resistant/sensitive Staphylococcus aureus.

Background and Objectives: Few studies have considered potential benefits of probiotic bacteria and their derivatives on human and animal health. Nisin is an antimicrobial agent that is produced by lactobacilli and served as a preservative in foods. This study aims to investigate whether nisin suppresses or decreases the genes involved in the pathogenicity of methicillin-susceptible and methicillin-resistant Staphylococcus aureus (MSSA and MRSA). Materials and Methods: MSSA and MRSA strains were cultured at the », ½, and 1 × minimum inhibitory concentration (MIC) of nisin. Next, RNA extraction was performed at the mid-exponential stage of growth, and cDNA was synthesized. The expression of virulence factors was measured by qPCR, and the data were analyzed by the ΔΔCt formula. Results: Depending on the incubation times and the Lactobacillus species, the MIC of nisin on MRSA and MSSA observed in 800 and 1600 mg/l, respectively. The qPCR assay showed the expression level of the sea, agrA, and spa genes decreased and the level of the sae gene increased at the sub-MIC of nisin, and no antagonism was observed. Concerning MRSA, the maximum downregulation rate was observed in the sea gene (up to 5.9 folds) while in MSSA, the maximum downregulation rate was noticed in the agrA gene (up to 10 folds). Conclusion: Due to the high inhibitory effect of the sub-MIC of nisin on the expression of virulence factor genes in MRSA and MSSA, this compound could potentially reduce the virulence of S. aureus.

Prevalence of Common Nosocomial Infections and Evaluation of Antibiotic Resistance Patterns in Patients with Secondary Infections in Hamadan, Iran.

INTRODUCTION: The prevalence of nosocomial infections in patients hospitalized to three hospitals of Shahid Beheshti, Farshchian, and Be' saat in Hamadan was investigated for 2 years (2018 to 2020). MATERIALS AND METHODS: The samples were cultured and characterized using morphological and diagnostic biochemical tests. The analysis of the frequency of the isolates and their antibiotic resistance were calculated using SPSS (version 22) at a significant level of P-value < 0.05. RESULTS: Bacterial isolates were collected from the 1194 clinical specimens, of which 1394 were isolated from urine, 16 from CSF, and 588 from tracheal aspiration. Also, 654 (54.8%) isolates were obtained from females and 540 (45.2%) from males with the age range 15-73 years (P> 0.05). The results showed that 22.1% were gram-positive and 77.9% were gram-negative. In our study, the frequency of Klebsiella pneumoniae bacteria was higher than in some studies, and this indicates the genetic changes and resistance of this bacterium to many antibiotics. CONCLUSION: To prevent further spread of resistance, increase the effectiveness of antibiotics and prevent multidrug resistance, it is essential to establish a precise schedule for the use of antibiotics and assess the resistance pattern periodically in each region based on the antibiotic resistance pattern.

Frequency of antibiotic associated diarrhea caused by Clostridium difficile among hospitalized patients in intensive care unit, Kerman, Iran.

AIM: This study evaluated the frequency of C. difficile and CDAD in the ICU of Shahid Bahonhar Hospital, Kerman, Iran. BACKGROUND: Clostridium difficile (C. difficile) is the most important antibiotic associated diarrhea agent in intensive care unit (ICU) patients. Based on its toxin producing ability, C .difficile is divided to toxigenic and non-toxigenic strains. METHODS: A total of 233 diarrheal samples were collected from ICU patients. The samples were cultured on Clostridium difficile medium with 5% defibrinated sheep blood containing cycloserine (500 mg/L), cefoxitin (16 mg/L) and lysozyme (5mg/L). The isolates were confirmed as C. difficile by polymerase chain reaction (PCR) of 16s rRNA gene and the presence of toxins genes (tcdA, tcdB, cdtA and cdtB) was also confirmed. Then, the toxin production of isolates was evaluated using ELISA. RESULTS: C. difficile was isolated from 49 (21%) out of 233 samples. The total isolates fell into the A-/B-/CDT- (48.97%), A+/B-/CDT- (28%), A+/B+/CDT- (20.4%) and A+/B+/CDT+ (2%) types. Both types of C.difficile, A-/B-/CDT- and A+/B-/CDT-, which account for 77.5% of all isolates, were unable to produce the toxin (nontoxigenic). On the other hand, A+/B+/CDT+ and A+/B+/CDT- (22.5%), were able to produce toxin or were toxigenic. CONCLUSION: The frequency of C. difficile was about 21% and only 22.4% of C. difficile isolates were able to produce toxins. It is expected that C. difficile A+/B+/CDT± are toxigenic and related to C. difficile associated diarrhea (CDAD). Additionally, about 4.7% of hospitalized patients in ICU suffered from CDAD, which is higher than the rates reported from industrialized countries. Notably, 28% of isolates were C. difficile A+/B-/CDT- which only carries tcdA genes without toxin production.

Common HBV genotype in southeastern Iranian patients.

Asymptomatic hepatitis B infection is characterized as a type of hepatitis in which hepatitis B surface antigen is present in the patient's peripheral blood despite the absence of clinical symptoms. Previous studies have shown that a particular genotype may effect clinical manifestations of hepatitis B infection; hence, the aim of the current study was to determine the frequency of hepatitis B virus genotypes among asymptomatic carriers of hepatitis B.In this experimental study, the plasma samples of 100 asymptomatic carriers were collected and tested for HBsAg and anti-HBs using ELISA. The genotype of hepatitis B virus was determined by the GAP-PCR technique. The results of this study showed that all samples were positive for hepatitis B surface antigen and anti-hepatitis B core antigen was present in 60 (60%) cases. Our results also indicated that all patients had the D genotype of hepatitis B virus.