Novel antimicrobial applications of copper oxide nanoparticles after combination with tissue conditioner used in complete prostheses.

BACKGROUND: Tissue conditioners are used for treating and improving the tissues supporting complete dentures. On the other hand, recent advances in nanotechnology have revolutionized various fields of science, including dentistry. The present study aimed to investigate novel antimicrobial applications of copper oxide nanoparticle-based tissue conditioner used in complete prostheses. METHODS: The present experimental study included 126 tissue conditioner samples with different concentrations of copper oxide nanoparticles (20%, 10%, 5%, 2.5%, 1.25%, 0.625%, and 0% w/w). The samples were incubated with Enterococcus faecalis, Pseudomonas aeruginosa, and Candida albicans in 24-well plates for 24 h. Then, samples from the wells were re-incubated for 24 h, and the microorganisms were counted. RESULTS: The culture media containing E. faecalis and P. aeruginosa showed significantly different growth between different nanoparticle concentrations following 24 h (P < 0.001), showing a reduction in bacterial growth with increased nanoparticle concentration. Both bacteria did not show any growth at the 20% concentration. However, C. albicans showed significant differences in growth between different nanoparticle concentrations following 48 h (P < 0.001), showing a reduction in growth with increased nanoparticle concentration. Also, the least growth was observed at the 20% concentration. CONCLUSIONS: In conclusion, the CuO nanoparticles were prepared using a green synthesis methon in the suitable sizes. Moreover, the tissue conditioners containing CuO nanoparticles showed acceptable antimicrobial properties against E. faecalis, P. aeruginosa, and C. albicans.

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.

The effects of opium consumption on severity of disease on hospitalized COVID-19 patients in East of Iran, a prospective cohort study.

There are few theories and little empirical evidence about the bilateral impact of substance use and coronavirus disease 2019 (COVID-19), so a logical and accurate picture of this area is required. We investigated the effects of opium use on severity of disease on hospitalized COVID-19 patients in east of Iran. Demographic and clinical characteristics, vital signs, laboratory tests, mortality rate, type and duration of opium consumption in hospitalized patients who recovered from COVID-19 in the follow-up after 3 months were evaluated. In this study, 60 (20%) participants were the opium user and 251 (80%) were the non-user patients. Based on clinical symptoms, hypertension and systolic blood pressure in opium user were significantly higher than non-user patients (p < 0.05). In the laboratory tests, only the level of urea was higher in the opium positive group (37 [26.5-48.5] vs. 32 [23-43], respectively) and the percent of lymphocytes were lower in the opium positive (17 [8.2-25.8] vs. 18.7 [13.85-26.35], respectively). The initial therapies of both opium positive and negative infected patients showed not any significant changes (p > 0.05). Among the studied groups, one deceased case with COVID-19 was related to a drug user patient. Although, uses of opium reduced the levels of some risk factors, vital signs at admission and initial therapies during hospitalization in COVID-19 patients but it increased lung and heart diseases. Also, the severity of COVID-19 including hospitalization and mortality were associated with opium consumption.

The role of Staphylococcus aureus in cystic fibrosis pathogenesis and clinico-microbiological interactions.

Cystic fibrosis (CF) is a progressive and inherited disease that affects approximately 70000 individuals all over the world annually. A mutation in the cystic fibrosis transmembrane conductance regulator (CFTR) gene serves as its defining feature. Bacterial infections have a significant impact on the occurrence and development of CF. In this manuscript, we discuss the role and virulence factors of Staphylococcus aureus as an important human pathogen with the ability to induce respiratory tract infections. Recent studies have reported S. aureus as the first isolated bacteria in CF patients. Methicillin-resistant Staphylococcus aureus (MRSA) pathogens are approximately resistant to all ß-lactams. CF patients are colonized by MRSA expressing various virulence factors including toxins, and Staphylococcal Cassette Chromosome mec (SCCmec) types, and have the potential for biofilm formation. Therefore, variations in clinical outcomes will be manifested. SCCmec type II has been reported in CF patients more than in other SCCmec types from different countries. The small-colony variants (SCVs) as specific morphologic subtypes of S. aureus with slow growth and unusual properties can also contribute to persistent and difficult-to-treat infections in CF patients. The pathophysiology of SCVs is complicated and not fully understood. Patients with cystic fibrosis should be aware of the intrinsic risk factors for complex S. aureus infections, including recurring infections, physiological issues, or coinfection with P. aeruginosa.

Gut microbiota in neurological diseases: Melatonin plays an important regulatory role.

Melatonin is a highly conserved molecule produced in the human pineal gland as a hormone. It is known for its essential biological effects, such as antioxidant activity, circadian rhythm regulator, and immunomodulatory effects. The gut is one of the primary known sources of melatonin. The gut microbiota helps produce melatonin from tryptophan, and melatonin has been shown to have a beneficial effect on gut barrier function and microbial population. Dysbiosis of the intestinal microbiota is associated with bacterial imbalance and decreased beneficial microbial metabolites, including melatonin. In this way, low melatonin levels may be related to several human diseases. Melatonin has shown both preventive and therapeutic effects against various conditions, including neurological diseases such as Alzheimer's disease, Parkinson's disease, and multiple sclerosis. This review was aimed to discuss the role of melatonin in the body, and to describe the possible relationship between gut microbiota and melatonin production, as well as the potential therapeutic effects of melatonin on neurological diseases.

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.

Tuberculosis vaccine developments and efficient delivery systems: A comprehensive appraisal.

Despite the widespread use of the Bacillus Calmette-Guérin (BCG) vaccine, Mycobacterium tuberculosis (MTB) continues to be a global burden. Vaccination has been proposed to prevent and treat tuberculosis (TB) infection, and several of them are in different phases of clinical trials. Though vaccine production is in progress but requires more attention. There are several TB vaccines in the trial phase, most of which are based on a combination of proteins/adjuvants or recombinant viral vectors used for selected MTB antigens. In this review, we attempted to discuss different types of TB vaccines based on the vaccine composition, the immune responses generated, and their clinical trial phases. Furthermore, we have briefly overviewed the effective delivery systems used for the TB vaccine and their effectiveness in different vaccines.

The healing effect of Pseudomonas Quinolone Signal (PQS) with co-infection of Staphylococcus aureus and Pseudomonas aeruginosa: A preclinical animal co-infection model.

BACKGROUND: Because of the rise in antibiotic resistance and the control of pathogenicity, polymicrobial bacterial biofilms exacerbate wound infections. Since bacterial quorum sensing (QS) signals can dysregulate biofilm development, they are interesting therapeutic treatments. In this study, Pseudomonas Quinolone Signal (PQS) was used to treat an animal model of a wound that had both Staphylococcus aureus and Pseudomonas aeruginosa co-infection. METHODS: S. aureus and P. aeruginosa mono- and co-infection models were developed in vitro on the L-929 cell line and in an animal model of wound infection. Moreover, PQS was extracted and purified using liquid chromatography. Then, the mono- and co-infection models were treated by PQS in vitro and in vivo. RT-PCR analysis was used to look into changes in biofilm, QS, tissue regeneration, and apoptosis genes after the treatment. RESULTS: PQS significantly disrupted established biofilm up to 90% in both in vitro and in vivo models. Moreover, a 93% reduction in the viability of S. aureus and P. aeruginosa was detected during the 10 days of treatment in comparison to control groups. In addition, the biofilm-encoding and QS-regulating genes were down-regulated to 75% in both microorganisms. Also, fewer epithelial cells died when treated with PQS compared to control groups in both mono- and co-infection groups. CONCLUSION: According to this study, PQS may facilitate wound healing by stimulating the immune system and reducing apoptosis. It seems to be a potential medication to use in conjunction with antibiotics to treat infections that are difficult to treat.

Synergistic effects of nano curcumin mediated photodynamic inactivation and nano-silver@colistin against Pseudomonas aeruginosa biofilms.

BACKGROUND: Patients with burn injuries colonized by multidrug-resistant Pseudomonas aeruginosa face increased mortality risk. The efficacy of colistin, a last-resort treatment, is declining as resistance levels rise. P. aeruginosa's robust biofilm exacerbates antibiotic resistance. Photodynamic Inactivation (PDI) shows promise in fighting biofilm. MATERIALS AND METHODS: Nano curcumin (nCur) particles were synthesized, and their chemical characteristics were determined using zeta potential (ZP), dynamic light scattering analysis (DLS), energy-dispersive X-ray (EDX) analysis, and fourier transform infrared (FTIR). We conducted an MTT assay to assess the cytotoxicity of nCur-mediated PDI in combination with nanosilver colistin. The fractional biofilm inhibitory concentration (FBIC) of two P. aeruginosa clinical isolates and P. aeruginosa ATCC 27853 during nCur-mediated PDI@AgNPs@CL was determined using a 3-dimensional (3-D) checkerboard assay. To study the effect of nCur-mediated PDI@AgNPs@CL on lasI, lasR, rhlI, rhlR, pelA, and pslA gene expression, Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was conducted at each isolate's FBIC. The impact of treatments was also investigated using scanning electron microscopy (SEM). RESULTS: The ZP and mean DLS values of the nCur were 10.3 mV and 402.6 ± 24.6 nm, respectively. The distinct functional groups of nCur corresponded with the peaks of FTIR absorption. Moreover, the EDX analysis showed the ratios of different metals in nCur. Cell viability percentages of nCur-mediated PDI@AgNPs@CL at FBIC concentrations of clinical isolates Nos. 30, 354, and P. aeruginosa ATCC 27853 were 91.36 %, 83.20 %, and 92.48 %, respectively. nCur-mediated PDI@AgNPs@CL treatment showed synergistic effects in clinical isolates and P. aeruginosa ATCC 27853 in a 3-D checkerboard assay. All six of the investigated genes showed down-regulation after nCur-mediated PDI@AgNPs@CL treatment. The most suppressed gene during nCur-mediated PDI@AgNPs@CL treatment was the rhlR gene (-11.9-fold) of P. aeruginosa ATCC 27853. The SEM micrographs further proved the connecting cement reduction and biofilm mass mitigation following nCur-mediated PDI@AgNPs@CL treatments. CONCLUSIONS: The combined effect of nCur-mediated PDI and AgNPs@CL synergistically reduce the formation of biofilm in P. aeruginosa. This may be attributable to the suppression of the genes responsible for regulating the production of biofilms.

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.

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.

Preparation, Physicochemical Characterization, Antimicrobial Effects, Biocompatibility and Cytotoxicity of Co-Loaded Meropenem and Vancomycin in Mesoporous Silica Nanoparticles.

Mesoporous silica nanoparticles (MSNPs) have been reported as an effective system to co-deliver a variety of different agents to enhance efficiency and improve biocompatibility. This study was aimed at the preparation, physicochemical characterization, antimicrobial effects, biocompatibility, and cytotoxicity of vancomycin and meropenem co-loaded in the mesoporous silica nanoparticles (Van/Mrp-MSNPs). The prepared nanoparticles were explored for their physicochemical features, antibacterial and antibiofilm effects, biocompatibility, and cytotoxicity. The minimum inhibitory concentrations (MICs) of the Van/Mrp-MSNPs (0.12-1 µg/mL) against Staphylococcus aureus isolates were observed to be lower than those of the same concentrations of vancomycin and meropenem. The minimum biofilm inhibitory concentration (MBIC) range of the Van/Mrp-MSNPs was 8-64 µg/mL, which was lower than the meropenem and vancomycin MBICs. The bacterial adherence was not significantly decreased upon exposure to levels lower than the MICs of the MSNPs and Van/Mrp-MSNPs. The viability of NIH/3T3 cells treated with serial concentrations of the MSNPs and Van/Mrp-MSNPs were 73-88% and 74-90%, respectively. The Van/Mrp-MSNPs displayed considerable inhibitory effects against MRSA, favorable biocompatibility, and low cytotoxicity. The Van/Mrp-MSNPs could be a potential system for the treatment of infections.

Bile effects on the Pseudomonas aeruginosa pathogenesis in cystic fibrosis patients with gastroesophageal reflux.

Gastroesophageal reflux (GER) occurs in most cystic fibrosis (CF) patients and is the primary source of bile aspiration in the airway tract of CF individuals. Aspirated bile is associated with the severity of lung diseases and chronic inflammation caused by Pseudomonas aeruginosa as the most common pathogen of CF respiratory tract infections. P. aeruginosa is equipped with several mechanisms to facilitate the infection process, including but not limited to the expression of virulence factors, biofilm formation, and antimicrobial resistance, all of which are under the strong regulation of quorum sensing (QS) mechanism. By increasing the expression of lasI, rhlI, and pqsA-E, bile exposure directly impacts the QS network. An increase in psl expression and pyocyanin production can promote biofilm formation. Along with the loss of flagella and reduced swarming motility, GER-derived bile can repress the expression of genes involved in creating an acute infection, such as expression of Type Three Secretion (T3SS), hydrogen cyanide (hcnABC), amidase (amiR), and phenazine (phzA-E). Inversely, to cause persistent infection, bile exposure can increase the Type Six Secretion System (T6SS) and efflux pump expression, which can trigger resistance to antibiotics such as colistin, polymyxin B, and erythromycin. This review will discuss the influence of aspirated bile on the pathogenesis, resistance, and persistence of P. aeruginosa in CF patients.

Approaches to determine the efficiency of novel 3-phytase from Klebsiella pneumoniae and commercial phytase in broilers from 1 to 14 d of age.

This study aimed to evaluate the effects of a laboratory 3-phytase (the expression of the phyK gene, Lab-Phy) and a commercial 6-phytase (Quantum Blue 40 P, Com-Phy) alone and in combination (corn-soy-based diets) in broilers. A total of 400, day-old Ross 308 male broilers were randomly assigned to 5 treatments with 10 replicate cages (8 chicks/cage) for a 14-day trial. Experimental treatments included the positive control (0.95% Ca and 0.48% nonphytate phosphorus (nPP), PC), negative control (0.90% Ca and 0.22% nPP, NC), and NC which was supplemented with Lab-Phy 250 FTU/kg and Com-Phy 250 FTU/kg alone or in combination of Lab-Phy 125 FTU/kg and Com-Phy 125 FTU/kg. The inclusion of Lab-Phy in the NC diet significantly improved the P and Ca content in the tibia compared to the NC group. Moreover, the inclusion of Com-Phy alone and in combination with Lab-Phy in the NC diet significantly increased the P and Ca content in the tibia compared to the Lab-Phy. The mRNA expression of NaPi-IIb was upregulated in the duodenum by the reduction of nPP and downregulated by the inclusion of any phytase, whereas other nutrient transporters were not influenced by the reduction of nPP or the addition of phytase in the small intestine mucosa. Broilers receiving the NC diet obtained the lowest body weight (BW) and body weight gain (BWG) at 8 to 14 and 1 to 14 d of age. The NC group showed the lowest villi height and surface area, Newcastle disease (ND) antibody titer, and digestibility of nutrients compared to the PC group at 14 d of age. Supplementing the NC diet with the Lab-Phy and Com-Phy individually, or in combination tended to improve BW, BWG, tibia characteristics, villi characteristics, ND, and retained CP and P, and apparent ileal digestibility of CP, P, methionine, and threonine. The present research indicated that the studied traits by the combination of phytases were slightly better than the average of the 2 individually, suggesting there might be some value in combining the laboratory and commercial phytases.

Caccinia macranthera Brand var. macranthera: Phytochemical analysis, phytotoxicity and antimicrobial investigations of essential oils with concomitant in silico molecular docking based on OPLS force-field.

This study was conducted to extract the essential oils (EOs) of Caccinia macranthera identify their phytochemicals, evaluate their phytotoxicity, antimicrobial activity and enzyme inhibition effects using in silico molecular docking technique. EOs of aerial parts, seeds, and roots of C. macranthera were extracted and analyzed via Gas chromatography-Mass Spectrometry. The antibacterial activity of EOs were determined on nine microorganisms via disk diffusion and microbroth dilution assays. In addition, the allelopathic properties of EOs were investigated by calculating the IC50s for inhibition of germination, seedling length and seedling weight growth of Cuscuta campestris seeds. In order to assess the possible inhibitory effect of major components of C. macranthera EOs on enzymes inhibiting germination and plant growth, molecular docking was employed against the glutamine synthetase (GS), acetohydroxyacid synthetase (AHAS), and 4-hydroxyphenyl pyruvate dioxygenase (HPPD) enzymes. The main compounds of EOs from aerial parts, seeds, and roots EOs were dihydrocarveol (29.5%), Trimethyl-2-Pentadecanone (13.6%), and Palmitic acid (16.8%), respectively. The maximum antibacterial effect was related to the aerial parts EO against Staphylococcus epidermidis. Phytotoxicity analysis exhibited a concentration-dependent increase (p ≤ 0.05) activity. The aerial parts EO demonstrated a substantial allelopathy effect, with IC50 values of 0.22 ± 0.026, 0.39 ± 0.021, and 0.20 ± 0.025 mg/mL, respectively, on inhibitory germination, seedling length and seedling weight growth of Cuscuta campestris seeds. Molecular docking analyzes showed that Oleic acid was suitable for dynamic stabilization of HPPD (-6.552 kJ/mol) and GS (-7.265 kJ/mol) and Eupatoriochromene had the inhibitory potential against AHAS, with docking score of -4.189 kJ/mol. The current research demonstrated that C. macranthera EOs from its aerial parts have an acceptable phytotoxic activity against Cuscuta campestris weed. The major components of EOs, Oleic acid and Eupatoriochromene, presented the strongest binding with HPPD, GS, and AHAS active sites causing disturbance in germination, photosynthesis and weed growth suggesting it as a natural herbicide for controlling the weeds.

Bacterial Contamination of Collected Cockroaches and Determination Their Antibiotic Susceptibility in Khorramabad City, Iran.

Background: Cockroaches are one of the most important carriers of pathogenic microorganisms. Therefore, the presence of cockroaches in public places, especially in hospitals, homes, and restaurants, is dangerous, and threatens the health of society, people, and the environment. The aim of this study was evaluation of bacterial contamination of cockroaches and the sensitivity of these bacteria to various antibiotics, captured from Khorramabad City, Iran. Methods: This descriptive cross-sectional study was performed on 150 cockroaches collected from hospital environments, homes, and restaurants in Khorramabad. The outer surface of the cockroaches was washed with physiological saline. The suspension was centrifuged for 5 minutes at 2000rpm. Isolation and identification of bacteria was performed using phenotypic methods. Antibiotic susceptibility testing was performed by disk diffusion method according to Clinical and Laboratory Standard Institute (CLSI) guideline. Results: A total of 100 American cockroaches (66.66%), 28 B. germanica (18.66%) and 22 Blatta orientalis (14.66%) were identified. In total, 97.33% of the collected cockroaches were infected with bacteria. The most bacterial infection of the cockroaches was Escherichia coli, coagulase-negative Staphylococci and Bacillus respectively. The overall results of the antibiogram test showed that the identified bacteria were resistant to cephalothin, ampicillin, cefotaxime, and kanamycin antibiotics, semi-sensitive to ciprofloxacin and sensitive to tetracycline, gentamicin, nitrofurantoin, Trimethoprim/sulfamethoxazole, and Chloramphenicol. Conclusion: Infection of cockroaches with pathogenic bacterial agents in hospital, residential, and restaurant environments, as well as the observation of bacterial resistance to some common antibiotics is worrying.

Relationship between antibiotic resistance with class 1 integron and SmeDEF efflux pump encoding genes in clinical isolates of Stenotrophomonas maltophilia.

Stenotrophomonas maltophilia is an emerging multidrug-resistant organism with an increasing frequency of hospital-acquired infections predominantly in developing countries. The purpose of this study was to determine the antibiotic resistance and frequency of the smeD, class 1 integron, and sul1 genes in clinical isolates of S. maltophilia in two Iranian provinces. From January 2020 to September 2021, 38 clinical isolates of S. maltophilia were collected from patients in hospitals in Tabriz and Sanandaj provinces of Iran. S. maltophilia isolates were confirmed by standard bacteriological tests and 16S rRNA gene PCR. Disk diffusion and the MIC test strip methods were used to determine the antibiotic resistance patterns. PCR was performed to investigate the presence of smeD, class 1 integron, and sul1 genes. The antimicrobial test for the isolated S. maltophilia showed a high level of sensitivity against most of the antibiotics used. Maximum sensitivity was recorded for ciprofloxacin (100% (38/38)) and levofloxacin 100% (38/38), followed by ceftazidime (97.36% (37/38)), trimethoprim-sulfamethoxazole (81.57% (31/38)), ticarcillin-clavulanate (60.52% (23/38)), and piperacillin-tazobactam (55.26% (21/38)). We observed a high prevalence of smeD (100% (38/38)) and class 1 integron (94.73% (36/38)) genes in the isolates, and none of the isolates carried the sul1 gene. The findings from this study indicate that resistance to trimethoprim-sulfamethoxazole was not observed, and still, trimethoprim-sulfamethoxazole is the best drug with desirable antimicrobial effect in the treatment of nosocomial infections caused by S. maltophilia strains. Despite the observation of a high number of class 1 integron, the sul1 gene was not observed, which indicates the role of this gene in high-level trimethoprim-sulfamethoxazole resistance and not having a role in low-level resistance. Based on our results, clinical microbiology laboratories need continuous surveillance of resistance rates to trimethoprim-sulfamethoxazole, because of the possibility of S. maltophilia acquiring trimethoprim-sulfamethoxazole-resistance by mobile gen elements.

Short-chain fatty acids profile in patients with SARS-CoV-2: A case-control study.

Background and Aims: SARS-CoV-2, as a new pandemic disease, affected the world. Short-chain fatty acids (SCFAs) such as acetic, propionic, and butyric acids are the main metabolites of human gut microbiota. The positive effects of SCFAs have been shown in infections caused by respiratory syncytial virus, adenovirus, influenza, and rhinovirus. Therefore, this study aimed to evaluate the concentration of SCFAs in patients with SARS-CoV-2 compared with the healthy group. Methods: This research was designed based on a case and control study. Twenty healthy individuals as the control group and 20 persons admitted to the hospital with a positive test of coronavirus disease (COVID-19) real-time polymerase chain reaction were included in the study as the patient group from September 2021 to October 2021, in Tabriz, Iran. Stool specimens were collected from volunteers, and analysis of SCFAs was carried out by a high-performance liquid chromatography system. Results: The amount of acetic acid in the healthy group was 67.88 ± 23.09 µmol/g, while in the group of patients with COVID-19 was 37.04 ± 13.29 µmol/g. Therefore, the concentration of acetic acid in the patient group was significantly (p < 0.001) lower than in the healthy group. Propionic and butyric acid were present in a higher amount in the control group compared with the case group; however, this value was not statistically significant (p > 0.05). Conclusion: This study showed that the concentration of acetic acid as the metabolite caused by gut microbiota is significantly disturbed in patients with COVID-19. Therefore, therapeutic interventions based on gut microbiota metabolites in future research may be effective against COVID-19.

Collateral sensitivity: An evolutionary trade-off between antibiotic resistance mechanisms, attractive for dealing with drug-resistance crisis.

Background: The discovery and development of antimicrobial drugs were one of the most significant advances in medicine, but the evolution of microbial resistance limited the efficiency of these drugs. Aim: This paper reviews the collateral sensitivity in bacteria and its potential and limitation as a new target for treating infections. Results and Discussion: Knowledge mechanisms of resistance to antimicrobial agents are useful to trace a practical approach to treat and control of resistant pathogens. The effect of a resistance mechanism to certain antibiotics on the susceptibility or resistance to other drugs is a key point that may be helpful for applying a strategy to control resistance challenges. In an evolutionary trade-off known as collateral sensitivity, the resistance mechanism to a certain drug may be mediated by the hypersensitivity to other drugs. Collateral sensitivity has been described for different drugs in various bacteria, but the molecular mechanisms affecting susceptibility are not well demonstrated. Collateral sensitivity could be studied to detect its potential in the battle against resistance crisis as well as in the treatment of pathogens adapting to antibiotics. Collateral sensitivity-based antimicrobial therapy may have the potential to limit the emergence of antibiotic resistance.

Immunologic biomarkers for bacterial meningitis.

Meningitis is defined as the inflammation of the meninges that is most often caused by various bacterial and viral pathogens, and is associated with high rates of mortality and morbidity. Early detection of bacterial meningitis is essential to appropriate antibiotic therapy. Alterations in immunologic biomarkers levels have been considered the diagnostic approach in medical laboratories for the identifying of infections. The early increasing immunologic mediators such as cytokines and acute phase proteins (APPs) during bacterial meningitis have made they significant indicators for laboratory diagnosis. Immunology biomarkers showed wide variable sensitivity and specificity values that influenced by different reference values, selected a certain cutoff point, methods of detection, patient characterization and inclusion criteria, as well as etiology of meningitis and time of CSF or blood specimens' collection. This study provides an overview of different immunologic biomarkers as diagnostic markers for the identification of bacterial meningitis and their efficiencies in the differentiating of bacterial from viral meningitis.