COVID-19 associated Mucormycosis among ICU patients: risk factors, control, and challenges.

The severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) pandemic is still difficult to be controlled. The spread of this virus and the emergence of new variants are considered a great challenge worldwide. Disturbance in infection control guidelines implementation, use of steroids, antibiotics, hospital crowdedness, and repeated use of oxygen masks during the management of critically ill COVID-19 patients lead to an increase in the rate of opportunistic infections. So, patients need to fight both the virus with its different variants and opportunistic pathogens including bacteria and fungi especially patients with diabetes mellitus, malignancy, or those who undergo hemodialysis and receive deferoxamine. During the pandemic, many cases of Mucormycosis associated with COVID-19 infection were observed in many countries. In this review, we discuss risk factors that increase the chance of infection by opportunistic pathogens, especially fungal pathogens, recent challenges, and control measures.

Effect of Titanium Dioxide Nanoparticles on the Expression of Efflux Pump and Quorum-Sensing Genes in MDR Pseudomonas aeruginosa Isolates.

Most of the infections caused by multi-drug resistant (MDR) P. aeruginosa strains are extremely difficult to be treated with conventional antibiotics. Biofilm formation and efflux pumps are recognized as the major antibiotic resistance mechanisms in MDR P. aeruginosa. Biofilm formation by P. aeruginosa depends mainly on the cell-to-cell communication quorum-sensing (QS) systems. Titanium dioxide nanoparticles (TDN) have been used as antimicrobial agents against several microorganisms but have not been reported as an anti-QS agent. This study aims to evaluate the impact of titanium dioxide nanoparticles (TDN) on QS and efflux pump genes expression in MDR P. aeruginosa isolates. The antimicrobial susceptibility of 25 P. aeruginosa isolates were performed by Kirby-Bauer disc diffusion. Titanium dioxide nanoparticles (TDN) were prepared by the sol gel method and characterized by different techniques (DLS, HR-TEM, XRD, and FTIR). The expression of efflux pumps in the MDR isolates was detected by the determination of MICs of different antibiotics in the presence and absence of carbonyl cyanide m-chlorophenylhydrazone (CCCP). Biofilm formation and the antibiofilm activity of TDN were determined using the tissue culture plate method. The effects of TDN on the expression of QS genes and efflux pump genes were tested using real-time polymerase chain reaction (RT-PCR). The average size of the TDNs was 64.77 nm. It was found that TDN showed a significant reduction in biofilm formation (96%) and represented superior antibacterial activity against P. aeruginosa strains in comparison to titanium dioxide powder. In addition, the use of TDN alone or in combination with antibiotics resulted in significant downregulation of the efflux pump genes (MexY, MexB, MexA) and QS-regulated genes (lasR, lasI, rhll, rhlR, pqsA, pqsR) in comparison to the untreated isolate. TDN can increase the therapeutic efficacy of traditional antibiotics by affecting efflux pump expression and quorum-sensing genes controlling biofilm production.

Comparative Study of Antibacterial Effects of Titanium Dioxide Nanoparticles Alone and in Combination with Antibiotics on MDR Pseudomonas aeruginosa Strains.

INTRODUCTION: The efficacy of several antimicrobial agents has been hindered due to the increasing frequency of multidrug-resistant (MDR) Pseudomonas aeruginosa strains. So, the need for new antibacterial drugs or drug combinations is urgent. Recently, desirable antibacterial effects were reported for many metals nanoparticles such as TiO2 nanoparticles (TDNs). PURPOSE: This study aims to investigate the prevalence of MDR P. aeruginosa and assess the efficiency of TDN in the treatment of MDR P. aeruginosa-associated infections. MATERIALS AND METHODS: The synthesis of TDN by the sol-gel method was carried out. Particle size measurements and morphology were done using dynamic light scattering (DLS) and high-resolution transmission electron microscopy (HR-TEM). To investigate the physical and chemical changes of drugs due to the combination, the tested drugs, both alone and in combination with TDN, were subjected to differential scanning calorimetry (DSC), infrared (IR) spectroscopy, and X-ray diffraction studies. Antimicrobial susceptibility was detected by agar disc-diffusion assay. The minimum inhibitory concentration (MIC) of TDN and the tested antibiotics were assessed by the agar dilution method. Checkerboard analysis was performed to determine the combined effect of TDN and the tested antibiotics against 25 MDR P. aeruginosa strains. RESULTS: TDNs were prepared with an average particle size of 64.77 ± 0.14 nm with an accepted polydispersity index (PDI) value of 0.274 ± 0.004. TEM showed that the particles were shaped into irregular spheres. Twenty-five P. aeruginosa isolates that were absolutely resistant to cefepime (100%), highly resistant to ceftriaxone (96%), amikacin (80%), and ciprofloxacin (76%) were selected. Superior antibacterial activity of TDN was observed against the selected 25 MDR P. aeruginosa isolates. The combination of TDN and cefepime were found to show synergistic activity against all tested isolates followed by ceftriaxone (96%), amikacin (88%), and ciprofloxacin (80%). CONCLUSION: Using TDN in combination with antibiotics can help in the treatment of MDR P. aeruginosa-associated infections. So, preparation of topical pharmaceutical dosage forms containing a combination of these antibiotics and TDN can be useful against MDR P. aeruginosa.

Endovascular management of nonvariceal upper gastrointestinal hemorrhage.

Upper gastrointestinal bleeding (UGIB) remains a frequent presentation in the emergency department. There are several causes of UGIB, which can be generally classified into variceal and nonvariceal bleeding. Although most cases of nonvariceal UGIB spontaneously resolve or respond to medical management and/or endoscopic treatment, transcatheter arterial embolization (TAE) remains an important available tool in the emergency evaluation and management of nonvariceal UGIB. In this article, we will discuss the current strategies for rendering a specific diagnosis of nonvariceal UGIB, and we will focus on the various TAE techniques for its management. We will also provide an algorithm for the diagnostic work-up of these patients. The majority of patients with nonvariceal UGIB that is refractory to endoscopic treatment is successfully treated with minimally invasive TAE and can avoid undergoing surgery.