Staphopain mediated virulence and antibiotic resistance alteration in co-infection of Staphylococcus aureus and Pseudomonas aeruginosa: an animal model.

Polymicrobial communities lead to worsen the wound infections, due to mixed biofilms, increased antibiotic resistance, and altered virulence production. Promising approaches, including enzymes, may overcome the complicated condition of polymicrobial infections. Therefore, this study aimed to investigate Staphopain A-mediated virulence and resistance alteration in an animal model of Staphylococcus aureus and Pseudomonas aeruginosa co-infection. S. aureus and P. aeruginosa were co-cultured on the L-929 cell line and wound infection in an animal model. Then, recombinant staphopain A was purified and used to treat mono- and co-infections. Following the treatment, changes in virulence factors and resistance were investigated through phenotypic methods and RT-PCR. Staphopain A resulted in a notable reduction in the viability of S. aureus and P. aeruginosa. The biofilm formed in the wound infection in both animal model and cell culture was disrupted remarkably. Moreover, the biofilm-encoding genes, quorum sensing regulating genes, and virulence factors (hemolysin and pyocyanin) controlled by QS were down-regulated in both microorganisms. Furthermore, the resistance to vancomycin and doripenem decreased following treatment with staphopain A. According to this study, staphopain A might promote wound healing and cure co-infection. It seems to be a promising agent to combine with antibiotics to overcome hard-to-cure infections.

Characterization of recombinant phytase of Klebsiella sp. and the influence of novel 3-phytase on mineral solubility in broiler diets under an in vitro digestion assay.

Phytate (inositol hexaphosphate) is the major storage form of phosphorus (P) in nature, and phytases catalyze the hydrolysis of P from phytate and the formation of inositol phosphate isomers. In this study, a bacterium that produces phytase was isolated in a phytase screening medium. The bacterium was identified as Klebsiella sp. using phenotypic and molecular techniques. The PhyK phytase gene was successfully amplified from the genome, inserted into the pET-21a (+) vector, and expressed as a recombinant protein in E. Coli BL21. The efficiency of a laboratory phytase (Lab-Ph, PhyK phytase) was determined and compared with a commercial phytase (Com-Ph, Quantum Blue 40P phytase, AB Vista) under an in vitro digestion assay. The native signal peptide effectively facilitated the translocation of the protein to the periplasmic space of E. Coli BL21, resulting in the proper folding of the protein and the manifestation of desirable enzyme activity. The Lab-Ph displayed the temperature and pH optima at 50 °C and 5 respectively. In addition, the Lab-Ph was inactivated at 80 °C. Under an in vitro digestion assay condition, Lab-Ph improved the P solubility coefficient in broiler diets. In comparison, the Com-Ph significantly increased the P solubility coefficient even when compared with the Lab-Ph. In summary, this study has shown that Lab-Ph possesses the necessary biochemical properties to be used in various industrial applications. However, Lab-Ph is extremely sensitive to heat treatment. The Lab-Ph and Com-Ph under an in vitro digestion assay improved the solubility coefficient of P in the broiler diet.

Epidemiological characterization of clinical isolates of meticillin resistant Staphylococcus aureus through multilocus sequence typing and staphylococcal cassette chromosome mec typing in Northwest Iran.

BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA), is considered a potential and aggressive nosocomial pathogen. It accounts for 50% of S. aureus isolates in tertiary hospitals in Iran, however, there is no sufficient evolutionary and epidemiological investigation about this medically important bacterium. We aimed to study the lineage and evolution of MRSA in Northwest Iran during 2021-2022 based on the obtained phenotypic and genotypic characteristics. MATERIALS AND METHODS: Seventy-two non-duplicate MRSA isolates were collected from 3 referral hospitals in Tabriz, Ardebil, and Urmia cities. The antimicrobial susceptibility patterns were determined by disk diffusion test and micro broth dilution methods. Thereafter 4 virulence genes (eta, etb, pvl, tst) and 5 types of staphylococcal cassette chromosome mec (SCCmec) were detected by PCR. In the final step, representative isolates were selected to be studied by Multilocus sequence typing (MLST). RESULTS: The highest resistance was observed to erythromycin and clindamycin at a rate of 76.4%, followed by ciprofloxacin (61.1%), gentamicin (54.2%), rifampin (38.9%), and co-trimoxazole (27.8%). All isolates were susceptible to vancomycin. The virulence genes of etb, pvl, tst, and eta were detected in 50%, 29.2%, 21.8%, and 13.9% of isolates, respectively. SCCmec types III and I were the most prevalent types, followed by types IV, II, and V. MLST analysis revealed 6 sequence types: ST6854, ST5282, ST127, ST7804, ST1607, and ST7784. Two MLST-based clonal complexes (CC8, and CC97) were identified as well. CONCLUSION: The ST numbers were non-repetitive. CC8 as a pandemic clone and an individual lineage and clinically significant clade was reported as the most prevalent clonal complex. It is essential periodic evaluations of antibiotic susceptibility patterns and study the evolutionary characteristics of medical-challenging microorganisms in particular MRSA to effectively treat and restrict the outbreaks.

Investigation of antimicrobial resistance patterns and molecular typing of Pseudomonas aeruginosa isolates among Coronavirus disease-19 patients.

BACKGROUND: Pseudomonas aeruginosa is a common co-infecting pathogen recognized among COVID-19 patients. We aimed to investigate the antimicrobial resistance patterns and molecular typing of Pseudomonas aeruginosa isolates among Coronavirus disease-19 patients. METHODS: Between December 2020 and July 2021, 15 Pseudomonas aeruginosa were isolated from COVID-19 patients in the intensive care unit at Sina Hospital in Hamadan, west of Iran. The antimicrobial resistance of the isolates was determined by disk diffusion and broth microdilution methods. The double-disk synergy method, Modified Hodge test, and polymerase chain reaction were utilized to detect Pseudomonas aeruginosa extended spectrum beta-lactamase and carbapenemase producers. Microtiter plate assay was performed to evaluate the biofilm formation ability of the isolates. The isolates phylogenetic relatedness was revealed using the multilocus variable-number tandem-repeat analysis method. RESULTS: The results showed Pseudomonas aeruginosa isolates had the most elevated resistance to imipenem (93.3%), trimethoprim-sulfamethoxazole (93.3%), ceftriaxone (80%), ceftazidime (80%), gentamicin (60%), levofloxacin (60%), ciprofloxacin (60%), and cefepime (60%). In the broth microdilution method, 100%, 100%, 20%, and 13.3% of isolates showed resistance to imipenem, meropenem, polymyxin B, and colistin, respectively. Ten (66.6%) isolates were identified as multiple drug resistance. Carbapenemase enzymes and extended spectrum beta-lactamases were identified in 66.6% and 20% of the isolates, respectively and the biofilm formation was detected in 100% of the isolates. The blaOXA-48, blaTEM, blaIMP, blaSPM, blaPER, blaVEB, blaNDM, blaSHV, and blaCTX-M genes were detected in 100%, 86.6%, 86.6%, 40%, 20%, 20%, 13.3%, 6.6%, and 6.6% of the isolates, respectively. The blaVIM, blaGIM, blaGES, and blaMCR-1 genes were not identified in any of the isolates. The MLVA typing technique showed 11 types and seven main clusters and most isolates belong to cluster I, V and VII. CONCLUSION: Due to the high rate of antimicrobial resistance, as well as the genetic diversity of Pseudomonas aeruginosa isolates from COVID-19 patients, it is indispensable to monitor the antimicrobial resistance pattern and epidemiology of the isolates on a regular basis.

Circular RNAs in tuberculosis: From mechanism of action to potential diagnostic biomarker.

Tuberculosis (TB), caused by Mycobacterium tuberculosis (M. tuberculosis), continues to be a major global health concern. Understanding the molecular intricacies of TB pathogenesis is crucial for developing effective diagnostic and therapeutic approaches. Circular RNAs (circRNAs), a class of single-stranded RNA molecules characterized by covalently closed loops, have recently emerged as potential diagnostic biomarkers in various diseases. CircRNAs have been demonstrated to modulate the host's immunological responses against TB, specifically by reducing monocyte apoptosis, augmenting autophagy, and facilitating macrophage polarization. This review comprehensively explores the roles and mechanisms of circRNAs in TB pathogenesis. We also discuss the growing body of evidence supporting their utility as promising diagnostic biomarkers for TB. By bridging the gap between fundamental circRNA biology and TB diagnostics, this review offers insights into the exciting potential of circRNAs in combatting this infectious disease.

Antibacterial and biofilm-inhibitory effects of vancomycin-loaded mesoporous silica nanoparticles on methicillin-resistant staphylococcus aureus and gram-negative bacteria.

The present study aimed to prepare and characterize vancomycin-loaded mesoporous silica nanoparticles (Van-MSNs) to detect inhibitory effects on the planktonic and biofilm forms of methicillin-resistant Staphylococcus aureus (MRSA) isolates, and study the biocompatibility and toxicity of Van-MSNs in vitro as well as antibacterial activity of Van-MSNs against Gram-negative bacteria. The inhibitory effects of Van-MSNs were investigated on MRSA using the determination of minimum inhibitory (MIC) and minimum biofilm-inhibitory concentrations (MBIC) as well as the effect on bacterial attachment. Biocompatibility was studied by examining the effect of Van-MSNs on the lysis and sedimentation rate of red blood cells (RBC). The interaction of Van-MSNs with human blood plasma was detected by the SDS-PAGE approach. The cytotoxic effect of the Van-MSNs on human bone marrow mesenchymal stem cells (hBM-MSCs) was evaluated by the MTT assay. The antibacterial effects of vancomycin and Van-MSNs on Gram-negative bacteria were also investigated using MIC determination using the broth microdilution method. Furthermore, bacteria outer membrane (OM) permeabilization was determined. Van-MSNs showed inhibitory effects on planktonic and biofilm forms of bacteria on all isolates at levels lower than MICs and MBICs of free vancomycin, but the antibiofilm effect of Van-MSNs was not significant. However, Van-MSNs did not affect bacterial attachment to surfaces. Van-loaded MSNs did not show a considerable effect on the lysis and sedimentation of RBC. A low interaction of Van-MSNs was detected with albumin (66.5 kDa). The hBM-MSCs viability in exposure to different levels of Van-MSNs was 91-100%. MICs of ≥ 128 µg/mL were observed for vancomycin against all Gram-negative bacteria. In contrast, Van-MSNs exhibited modest antibacterial activity inhibiting the tested Gram-negative bacterial strains, at concentrations of ≤ 16 µg/mL. Van-MSNs increased the OM permeability of bacteria that can increase the antimicrobial effect of vancomycin. According to our findings, Van-loaded MSNs have low cytotoxicity, desirable biocompatibility, and antibacterial effects and can be an option for the battle against planktonic MRSA.

Polymorphisms in vitamin D receptor genes and its relation with susceptibility to brucellosis: a case-control study.

OBJECTIVE: One of the systemic infections is Brucellosis which is caused by facultative intracellular bacteria of the genus Brucella. Vitamin D is a fat-soluble prohormone, that metabolizes enzymes and its intracellular receptor creates the active hormone and also mediate in responses of immune system. METHODS: Current research consists of 102 patients with brucellosis who were selected based on culture, PCR results serology, and clinical symptoms. The control group composed of 102 healthy people. The polymorphism of genes (Bsm I, Fok I, Taq I, Apa I) encoding Vitamin D receptor (VDR) were assessed by the PCR-RFLP method. RESULTS: The results showed that ff, tt, aa, and bb genotypes in Fok I, ApaI, TaqI, and BsmI were significant in case/control groups (P-value ≤ 0.0001). The genotype frequency AA in the control group is higher than that of the study group, while genotype frequency aa in the study group is more than the control. The odds ratio for brucellosis in individuals with ff genotype is 37 times higher than that of Ff genotype. Also, the odds ratio of brucellosis in individuals with genotype tt, aa, and bb was 12, 53, and 6 times higher than those of the Aa, Bb, and Tt genotypes. CONCLUSION: The genotypes aa and ff in the positions of the ApaI and FokI are of higher importance. The brucellosis risk in individuals accompanied aa genotype at Apa I is 53 times higher than that of the genotype AA, in other words, AA and BB, TT and FF genotypes are protective against the disease.

Preparation of rutin-loaded mesoporous silica nanoparticles and evaluation of its physicochemical, anticancer, and antibacterial properties.

BACKGROUND: The studies have shown that rutin has great potential as an anticancer and antimicrobial plant base agent; nevertheless, poor bioavailability and low aqueous solubility of rutin limit its application. One of the beneficial routes to increase the solubility and bioavailability of rutin is the development of nanoparticulate material. This study aimed to assess the anticancer and antibacterial effects of rutin-loaded mesoporous silica nanoparticles (RUT-MSNs). METHODS: RUT-MSNs were prepared and physicochemically characterized. The cytotoxicity of RUT-MSNs on the HN5 cells as head and neck cancer cells was evaluated. The expression level of apoptosis-related genes such as Bcl-2 and Bax genes were evaluated. In addition, ROS production of RUT-MSNs treated cells was assessed. In addition, minimum inhibitory concentration (MIC), biofilm, and attachment inhibitory effects of RUT-MSNs compared with free rutin were assessed against different bacterial strains. RESULTS: Transmission electron microscopy (TEM) showed mesoporous rod-shaped nanoparticles with an average particle size of less than 100 nm. RUT-MSNs displayed the cytotoxic effect with IC50 of 20.23 µM in 48 h of incubation time (p < 0.05). The elevation in the ratio of Bax/Bcl-2 was displayed within the IC50 concentration of RUT-MSNs in 48 h (p < 0.05). The antibacterial action of rutin was improved by loading rutin in MSNs to the nano-sized range in the MIC test. CONCLUSION: The anticancer and antibacterial effects of RUT-MSNs were considerably more than rutin. RUT-MSNs inhibited the growth of HN5 cells by inducing apoptosis and producing ROS. These results suggest that RUT-MSNs may be useful in the treatment of cancers and infections.

The Antibacterial Effect of Ciprofloxacin Loaded Calcium Carbonate (CaCO3) Nanoparticles Against the Common Bacterial Agents of Osteomyelitis.

The present study aimed to investigate the biocompatibility, antibacterial/anti-biofilm effects of ciprofloxacin-loaded calcium carbonate (Cip- loaded CaCO3) nanoparticles against the common organisms responsible for osteomyelitis. The antibacterial and biofilm inhibitory activities were studied by determination of minimum inhibitory concentrations (MICs) and minimum biofilm inhibitory concentrations (MBICs), respectively. Hemolytic effects were determined for studying hemocompatibility. The SDS-PAGE method was used to study the interaction of Cip- loaded CaCO3 with plasma proteins. The effects of Cip- loaded CaCO3 on the cell viability of human bone marrow mesenchymal stem cells (hBM-MSCs) was detected. The Cip- loaded CaCO3 nanoparticles were shown a significant antimicrobial effect at lower concentrations than free ciprofloxacin. No significant hemolytic effect was observed. The Cip- loaded CaCO3 nanoparticles have shown interaction with apolipoprotein A1 (28 kDa) and albumin (66.5 kDa). The viability of hBM-MSCs treated with Cip- loaded CaCO3 was more than 96%. Our results indicated that Cip-loaded CaCO3 nanoparticles had favorable in vitro compatibility with human red blood cells, antimicrobial effects, and low cytotoxicity.

Enhanced antibacterial activity of cadmium telluride nanocrystals in combination with 940-nm laser diode on anaerobic bacteria P. gingivalis: an in vitro study.

Periodontal disease is one of the most common chronic diseases in the oral cavity that causes tooth loss. Root scaling and leveling cannot eliminate all periodontal pathogens, and the use of antibacterial agents or lasers can increase the efficiency of mechanical methods. The aim of this study was to evaluate and compare the antibacterial activity of cadmium telluride nanocrystals in combination with 940-nm laser diode. Cadmium telluride nanocrystals were prepared by a green route of synthesis in aqueous medium. The results of this study showed that cadmium telluride nanocrystals significantly inhibit the growth of P. gingivalis. The antibacterial property of this nanocrystal increases with increasing its concentration, laser diode 940-nm irradiation and with increasing the time. It was shown that the antibacterial activity of combination of 940-nm laser diode and cadmium telluride nanocrystals is greater than the effect of either alone and can have a similar effect with its long-term presence of microorganisms. This is very important because it is not possible to use these nanocrystals in the mouth and in the periodontal bag for a long time.

Antimicrobial photodynamic therapy: modern technology in the treatment of wound infections in patients with burns.

BACKGROUND: Staphylococcus aureus is one of the most frequently isolated microorganisms from burn wounds. Antimicrobial photodynamic therapy (aPDT) is a new strategy that may improve antimicrobial treatment. METHOD: This study evaluated three meticillin-resistant Staphylococcus aureus (MRSA) and three meticillin-sensitive Staphylococcus aureus (MSSA) clinical isolates, which produced a biofilm with 0.1mg/ml Toluidine Blue O (TBO) (Sigma-Aldrich, Germany) with an energy density of 45J/cm2 and 90J/cm2, for MRSA and MSSA, respectively. The antibiofilm potential of aPDT with TBO was analysed using crystal violet assays and scanning electron microscopy. RESULTS: TBO-aPDT significantly degraded the biofilm formed by MRSA and MSSA clinical isolates (p<0.05). CONCLUSION: Our results indicated that aPDT is an effective approach to combat bacterial biofilms associated with burn wound infection. aPDT could provide a supplemental to the treatment of wound and tissue infection, and patients with burns may benefit from combined treatments.

Assessment of Association between miR-146a Polymorphisms and Expression of miR-146a, TRAF-6, and IRAK-1 Genes in Patients with Brucellosis.

BACKGROUND: Brucellosis is a major zoonosis all over the world. MicroRNAs are significant gene expression regulators and could be involved during the infections and also genetic alterations in the miRNAs sequence can affect primary miRNAs and precursor miRNAs processing and thus alter miRNAs expression. Current research studied the impact of the miR-146a polymorphism on miR-146a, TRAF-6, and IRAK-1 genes expression in patients with brucellosis illness. METHODS AND RESULTS: In this research, 25 patients with brucellosis and 25 healthy participants with determined genotypes for miR-SNP rs2910164 and miR-SNP rs57095329 were recruited. IRAK-1, TRAF-6, and miR-146a expressions in peripheral blood mononuclear cells (PBMCs) were specified by quantitative real- time PCR (qRT-PCR). Moreover, interleukin-1ß (IL-1ß) and tumor necrosis factor- alpha (TNF-α) serum levels were assessed by a sandwich enzyme-linked immunosorbent assay (ELISA) technique. There was no significant difference in the expression level of miR-146a, IRAK-1, and TRAF-6, among the patients with brucellosis and control group. TRAF-6 PBMCs expression levels in the distinctive genotypes of rs2910164 were significantly observed in patients (P = 0.048). No significant distinctions were found in miR-146a, IRAK-1, and TRAF-6 expression levels and among the rs57095329 different genotypes in brucellosis patients and controls. Meanwhile, no significant relationship was found between the rs2910164 and rs57095329 genotypes and the serum level of cytokines mentioned between the two groups. We did not find any association between expression of TRAF-6, miR-146a, and IRAK-1 in PBMCs, and cytokines serum levels with two single nucleotide polymorphisms (SNPs) in miR-146a. CONCLUSIONS: To the best of writers' knowledge, this research is the first one evaluating the probable link between the miR-146a rs2910164 and rs57095329 variant with miRNAs, relevant cytokine levels, and target genes in brucellosis.

Carbapenem resistance in Bacteroides fragilis: A review of molecular mechanisms.

Carbapenems are an applicable subclass of ß-lactam drugs in the antibiotic therapy of anaerobic infections, especially for poly-microbial cases, due to their broad antimicrobial spectrum on aerobic and anaerobic bacteria. Bacteroides fragilis is the most commonly recovered anaerobic bacteria in the clinical laboratories from mono- and poly-microbial infections. B. fragilis is relatively non-susceptible to different antibiotics, including ß-lactams, tetracyclines, fluoroquinolones, and macrolides. Carbapenems are among the most effective drugs against B. fragilis strains with high-level resistance to different antibiotics. Increased antibiotic resistance of B. fragilis strains has been reported following the overuse of an antimicrobial agent. Earlier contact with carbapenems is linked with increased resistance to them that limits the options for treatment of B. fragilis caused infections, especially in cases caused by multidrug-resistant strains. Several molecular mechanisms of resistance to carbapenems have been described for different carbapenem-resistant bacteria. Understanding the mechanisms of resistance to antimicrobial agents is necessary for selecting alternative antimicrobial agents and the application of control strategies. In the present study, we reviewed the mechanisms contributing to resistance to carbapenems in B. fragilis strains.

Systematic review and meta-analysis: Prevalence of hypertension among adolescents in the Arab countries.

PROBLEM: Hypertension (HTN) is one of the non-communicable diseases which prevalence is rising in both developed and developing countries. There is a scarcity of data on the prevalence of HTN in Arab countries. This review outlines what is currently known about prevalence and risk factors of HTN in adolescence in Arab world. ELIGIBILITY CRITERIA: A systematic review and meta-analysis were conducted using PubMed, Cochrane Library, Scopus, CINAHL, Science Direct, and Google Scholar databases from 2011 to 2021. SAMPLE: Fourteen studies from 9 Arab countries met inclusion criteria. Studies included a total of 777 adolescents with HTN and 2147 adolescents with pre-HTN. RESULTS: The overall prevalence of HTN among adolescents in the Arab World was estimated at 12.6% (95CI 0.083-0.176), while pre-HTN was 13.9% (95CI 0.084-0205). Overweight and obesity resemble the higher risk of developing hypertension. Family history, high consumption of salt, smoking and low physical activity also increase the risk of HTN. The development of adolescent HTN can be predicted through anthropometric measurements such as Body Mass Index (BMI), wrist circumferences, and high waist circumference. CONCLUSION: The prevalence of HTN among adolescents in the Arab world was significant, ranging from 4 to 26%. The heterogeneity between studies was high. IMPLICATION: Local governments and policymakers must consider strengthening regulations to address environmental risk factors and improve public awareness about risk factors to HTN. A combined use of nurse- and patient targeted educational interventions could also help in reducing the burden of HTN in this population.

The perceived threat of COVID-19 and its impact on hygienic precautionary behaviors: A multi-countries study.

OBJECTIVE(S): To explore the perceived threats of COVID-19 and how it changed the personal hygienic precautionary behaviors across multiple countries in the Middle East and North Africa (MENA) region. DESIGN: A cross-sectional descriptive design was used to survey the four targeted MENA countries: Jordan, Palestinian territories, Saudi Arabia, and Egypt. SAMPLE: A nonprobability convenience sampling design was utilized. The link to the survey questionnaire was distributed through social media groups within Facebook® and Twitter® . The groups are known and accessible by known across the general population at the targeted countries. MEASUREMENT: Data was collected using The Brief Illness Perception Questionnaire and an adapted instrument that examine the hygienic precautionary behaviors during COVID-19 pandemic. RESULTS: Answers of participants (n = 2604) were valid and included in the study. The results show that a minimal perception of threat among the participants on most of the BIP-Q5 items (M = 12.9, SD = 7.2). Moreover, the highest compliance rates to recommended hygienic precautionary behaviors were found among populations above the age of 50 years (F = 2.89, p = .04), females (t = 5.18, p = .003), being married (F = 3.09, p = .029), and being a health care professional (t = -2.20, p = .028). CONCLUSION: The perceived threat of COVID-19 and compliance rates with the recommended hygienic precautionary behaviors among Arab societies were found to below and need critically urgent attention.

Heat Transfer Analysis between R744 and HFOs inside Plate Heat Exchangers.

Plate heat exchangers (PHE) are used for a wide range of applications, thus utilizing new and unique heat sources is of crucial importance. R744 has a low critical temperature, which makes its thermophysical properties variation smoother than other supercritical fluids. As a result, it can be used as a reliable hot stream for PHE, particularly at high temperatures. The local design approach was constructed via MATLAB integrated with the NIST database for real gases. Recently produced HFOs (R1234yf, R1234ze(E), R1234ze(Z), and R1233zd(E)) were utilized as cold fluids flowing through three phases: Liquid-phase, two-phase, and gas-phase. A two-step study was performed to examine the following parameters: Heat transfer coefficients, pressure drop, and effectiveness. In the first step, these parameters were analyzed with a variable number of plates to determine a suitable number for the next step. Then, the effects of hot stream pressure and cold stream superheating difference were investigated with variable cold channel mass fluxes. For the first step, the results showed insignificant differences in the investigated parameters for the number of plates higher than 40. Meanwhile, the second step showed that increasing the hot stream pressure from 10 to 12 MPa enhanced the two-phase convection coefficients by 17%, 23%, 75%, and 50% for R1234yf, R1234ze(E), R1234ze(Z), and R1233zd(E), respectively. In contrast, increasing the cold stream superheating temperature difference from 5 K to 20 reduced the two-phase convection coefficients by 14%, 16%, 53%, and 26% for R1234yf, R1234ze(E), R1234ze(Z), and R1233zd(E), respectively. Therefore, the R744 is suitable for PHE as a driving heat source, particularly at higher R744 inlet pressure and low cold stream superheating difference.

Contribution of Arginine Catabolic Mobile Element and Copper and Mercury Resistance Element in Methicillin-Resistant Staphylococcus aureus: A Vantage Point.

Different clones of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) are dominating geographically. One of the significant, hypervirulent, CA-MRSA and a significant health concern clones is USA3000, found worldwide regionally with varying frequencies. The clone harbors several mobile genetic elements (MGEs) including, arginine catabolic mobile element (ACME) and copper and mercury resistance genes (COMER), accomplished by horizontal gene transfer from S. epidermidis. Evidence suggests that ACME and COMER have a more prominent role in enhancing biofilm capacity and ultimately persistent infections. This review highlights the comprehensive view on ACME and COMER structure, their distribution, and the mechanism of action along with pathogenetic features of USA3000 encompassing their role in biofilm formation, adhesion, quorum sensing, resistance to antibiotics, chemotaxis, and nutrient uptake. We also provided an insight into the role of ACME and COMER genes in the survival of bacterium. Our results shed light on the emergence of two independent clones possessing ACME (North American) and COMER (South American) elements which later disseminated to other regions. ACME and COMER both are adjacent to staphylococcal cassette chromosome mec type IV (SCCmec IV). The acquisition of mecA, followed by COMER or ACME has been shown as a significant factor in the rise and fall of MRSA strains and their complex ability to adapt to hostile environments. The presence of ACME increases fitness, thereby allowing bacteria to colonize the skin and mucous membrane while COMER contributes to genetic stability by knocking over the copper-mediated killing in macrophages. Evidence suggests that ACME and COMER have a more prominent role in enhancing biofilm capacity and ultimately persistent infections. Interestingly, ACME strains have been shown to possess the ability to counteract skin acidity, thereby allowing increased skin colonization. A profound understanding of MGEs in S. aureus plays an important role in the prevention of epidemic clones.

The Prevalence and Antibiotics Susceptibility Patterns of Corynebacterium minutissimum Isolates from Skin Lesions of Patients with Suspected Erythrasma from Tabriz, Iran.

Erythrasma is a chronic infection of the skin that appears in the body folds as flat copper spots. The causative agent of this infection is Corynebacterium minutissimum (C. minutissimum). Erythrasma can be treated with antiseptics or topical antibiotics. The study aimed to investigate the antibiotics susceptibility patterns, and the presence of the erythromycin resistance gene (ermX and mefA) in C. minutissimum isolates in skin lesions with suspected erythrasma. From July 2020 to May 2022, 278 skin scrub specimens were collected from patients admitted to the hospital of Tabriz University of Medical Sciences. Specimens were incubated on the blood agar plates and isolates were identified by microbiological laboratory methods. The antibiotic susceptibility patterns were determined by the disk diffusion method and resistance genes of ermX and mefA were detected by the PCR method. Out of 278 specimens, 41 C. minutissimum isolates (14.74%) were recovered. The highest frequency of resistance was observed to a penicillin (75.6%) followed by erythromycin and clarithromycin (39.02%), clindamycin (30.05%), tetracycline (24.2%), and gentamicin and neomycin (19.5%). The frequencies of ermX and mefA genes were 75% and 12.5%, respectively. Resistance to antimicrobial drugs was common and worrying. Resistance to erythromycin in C. minutissimum is mainly related to the ermX gene.

Global, Regional, and National Burden of Calcific Aortic Valve and Degenerative Mitral Valve Diseases, 1990-2017.

BACKGROUND: Nonrheumatic valvular diseases are common; however, no studies have estimated their global or national burden. As part of the Global Burden of Disease Study 2017, mortality, prevalence, and disability-adjusted life-years (DALYs) for calcific aortic valve disease (CAVD), degenerative mitral valve disease, and other nonrheumatic valvular diseases were estimated for 195 countries and territories from 1990 to 2017. METHODS: Vital registration data, epidemiologic survey data, and administrative hospital data were used to estimate disease burden using the Global Burden of Disease Study modeling framework, which ensures comparability across locations. Geospatial statistical methods were used to estimate disease for all countries, because data on nonrheumatic valvular diseases are extremely limited for some regions of the world, such as Sub-Saharan Africa and South Asia. Results accounted for estimated level of disease severity as well as the estimated availability of valve repair or replacement procedures. DALYs and other measures of health-related burden were generated for both sexes and each 5-year age group, location, and year from 1990 to 2017. RESULTS: Globally, CAVD and degenerative mitral valve disease caused 102 700 (95% uncertainty interval [UI], 82 700-107 900) and 35 700 (95% UI, 30 500-42 500) deaths, and 12.6 million (95% UI, 11.4 million-13.8 million) and 18.1 million (95% UI, 17.6 million-18.6 million) prevalent cases existed in 2017, respectively. A total of 2.5 million (95% UI, 2.3 million-2.8 million) DALYs were estimated as caused by nonrheumatic valvular diseases globally, representing 0.10% (95% UI, 0.09%-0.11%) of total lost health from all diseases in 2017. The number of DALYs increased for CAVD and degenerative mitral valve disease between 1990 and 2017 by 101% (95% UI, 79%-117%) and 35% (95% UI, 23%-47%), respectively. There is significant geographic variation in the prevalence, mortality rate, and overall burden of these diseases, with highest age-standardized DALY rates of CAVD estimated for high-income countries. CONCLUSIONS: These global and national estimates demonstrate that CAVD and degenerative mitral valve disease are important causes of disease burden among older adults. Efforts to clarify modifiable risk factors and improve access to valve interventions are necessary if progress is to be made toward reducing, and eventually eliminating, the burden of these highly treatable diseases.

Sewage and sewage-contaminated environments are the most prominent sources to isolate phages against Pseudomonas aeruginosa.

BACKGROUND: P. aeruginosa is the primary source of hospital-acquired infections. Unfortunately, antibiotic resistance is growing to precariously high levels, making the infections by this pathogen life-threatening and hard to cure. One possible alternative to antibiotics is to use phages. However, the isolation of phages suitable for phage therapy- be lytic, be efficient, and have a broad host range -against some target bacteria has proven difficult. To identify the best places to look for these phages against P. aeruginosa we screened hospital sewages, soils, and rivers in two cities. RESULTS: We isolated eighteen different phages, determined their host range, infection property, and plaque morphology. We found that the sewage and sewage-contaminated environments are the most reliable sources for the isolation of Pseudomonas phages. In addition, phages isolated from hospital sewage showed the highest efficiency in lysing the bacteria used for host range determination. In contrast, phages from the river had larger plaque size and lysed bacteria with higher levels of antibiotic resistance. CONCLUSIONS: Our findings provided additional support for the importance of sewage as the source of phage isolation.