Diagnosis of bacteremia in patients with suspected septicemia using polymerase chain reaction method

Background: Sepsis or blood stream infection is a clinical lethal syndrome with severe systemic inflammatory response to infection, if not treated quickly, is associated with dangerous consequences and high morbidity and mortality. The traditional and conventional method for identification of sepsis is blood culture method which is so time-consuming and long that it eliminates the possibility of rapid treatment. Although, new molecular methods, due to their high sensitivity, specificity, and speed, lead to the rapid and accurate and exact detection of bacterial sepsis within only a few hours. The aim of this study was diagnosis of bacteremia in patients with suspected sepsis using amplification of 23S rRNA gene by polymerase chain reaction (PCR). Methods: This cross-sectional study was performed in two clinical and analytical steps at Shahid Beheshti University Hospital in Kashan City, Iran, in twelve months from November 2016 to December 2017. The blood samples of two hundred and fifty-six patients with suspected sepsis admitted to Shahid Beheshti Hospital were studied by PCR method using specific primers of 23S rRNA gene of the bacteria. Results: The finding of molecular assays using PCR showed that of 256 blood samples that were collected from patients with clinical signs and symptoms of sepsis, 80 (30.2) diagnosed with bacteremia. Of these patients diagnosed with sepsis, 46 out of 80 (57.5) were male while 34 out of 80 (42.5) were female. The most PCR positive results were obtained among patients with diabetes and bedsore as underlying diseases (21.3). Statistical analysis showed that there was a significant correlation between results of molecular methods by PCR assays and history of antibiotic use. Conclusion: Overall, the results of the present study showed that the molecular methods such as polymerase chain reaction using universal 23S rRNA primers is an appropriated test for diagnosis of bacteremia in blood samples of patients with suspected sepsis. © 2020 Tehran University of Medical Sciences. All rights reserved

Molecular identification and antibiotic resistance pattern of actinomycetes isolates among immunocompromised patients in Iran, emerging of new infections

Recent advancements in DNA-based approaches have led to the identification of uncommon and rare bacterial pathogens. In this study, by utilizing a DNA-based approach, a total of 1043 clinical specimens were processed for the identification of actinobacteria targeting the 16S rRNA and gyrB genes. Drug susceptibility testing was also conducted using micro-broth dilution and PCR. Two isolates of Nocardia flavorosea and Rhodococcus erythropolis were reported for the first time in Iran. Also, Nocardiopsis dassonvillei, Streptomyces olivaceus, and Streptomyces griseus were reported for the first time in Asia. Infections caused by Nocardia caishijiensis and Prauserella muralis have also been reported in this study. The first Asian case of pulmonary infection caused by Nocardia ignorata and the first global case of brain abscess caused by Nocardia ninae and Nocardia neocaledoniensis have been reported in this study. Overall 30 isolates belonging to 6 genera (Nocardia, Streptomyces, Rodoccoccus, Nocardiopsis, Rothia, and Prauserella) were detected in 30 patients. All 30 isolates were susceptible to amikacin and linezolid. Three isolates including Nocardia otitidiscaviarum (n = 2) and Nocardia flavorosea (n = 1) were resistant to trimethoprim-sulfamethoxazole which were the first trimethoprim-sulfamethoxazole resistant clinical actinomycetes in Iran. Isolation of rare species of actinomycetes particularly Nocardia spp. requires urgent action before they spread clinically particularly among immunocompromised patients. © 2021, The Author(s)

Pd supported on magnetic carbon coated halloysite as hydrogenation catalyst: Study of the contribution of carbon layer and magnetization to the catalytic activity

In this article, a magnetic carbon-coated halloysite nanoclay (Hal) was prepared through introduction of hydrothermally carbonized glucose (Glu) on Hal followed by the immobilization of magnetic nanoparticles (MNPs) and incorporation of resorcinol-formaldehyde polymeric shell (RF) and carbonization. The resulting composite was then successfully applied for the immobilization of Pd nanoparticles to afford Pd@Hal@Glu-Fe-C that could efficiently promote hydrogenation of nitroarenes in the aqueous media at low temperature. The catalyst exhibited high selectivity toward nitro group. Moreover, it was highly recyclable with low MNPs and Pd leaching. To elucidate the contribution of each component of the support to the catalysis, a precise study was carried out by preparing several control catalysts and comparing their catalytic activities with that of Pd@Hal@Glu-Fe-C. Furthermore, the effect of carbon source used for the formation of hydrothermally derived carbon -wrapped Hal and the order of incorporation of metallic nanoparticles on the catalytic activity of the final catalyst was investigated