Avicenna Journal of Clinical Microbiology and Infection
Volume:8 Issue: 4, Dec 2021

Antibiotic resistance emerged in the pathogens causing urinary tract infections (UTIs) and became widespread. Moreover, increasing drug resistance has highlighted the need to evaluate the antibiotic resistance pattern to improve experimental treatment. The purpose of this study was to evaluate the bacteria causing UTIs and their susceptibility patterns based on the geographical area.

The present study was conducted on outpatients referred to Qal’at Saleh Hospital in Iraq from January 2018 to January 2019. The pathogenic bacteria were detected using API 20E kit. The antimicrobial susceptibility testing was conducted using the disk diffusion method according to the guidelines of the Clinical and Laboratory Standards Institute (CLSI).

Of 216 isolates, 87.9% contained gram-negative bacteria and 12.03% contained gram-positive bacteria. In this study, Escherichia coli was identified as the main cause of UTIs. Of all the isolates, 73.61% were resistant to three or more classes of antibiotics. The antibiotic susceptibility and resistance patterns of all isolates showed that amikacin and ciprofloxacin had the highest activity against gram-negative bacteria and vancomycin, amikacin, and levofloxacin had the highest activity against gram-positive bacteria.

Due to the widespread resistance to drugs used in the treatment of UTIs, it is difficult to select the appropriate drugs for treating UTIs. UTI affects different age groups; therefore, sufficient knowledge should be transferred to the community to prevent these infections. If urine culture is unavailable, or it is impossible to wait for antibiotic susceptibility testing, Amikacin and Vancomycin might be the best candidates for UTI treatment.

T Microorganisms cause many diseases for the human body such as urinary tract infection and, therefore, it is highly important to eliminate and control them. Bacterial resistance to different types of antibiotics was increased and it is necessary to find alternative agents to eliminate these microbes.

This study aimed was to evaluate the antimicrobial effect of different concentrations of titanium dioxide nanoparticles (TiO2 NPs) on some gram-positive bactria, gram-negative bacteria, and Candida albicans. TiO2 NPs were synthesized using the chemical methods, coated with carboxymethyl cellulose (CMC) and prepared in different concentrations (0.098, 0.196, 0.392, 0.784, 1.568, and 3.136 mg/mL). Eventually, a minimum inhibitory concentration (MIC) and a minimum biofilm inhibitory concentration (MBIC) were applied to investigate the effect of TiO2 NPs on microorganisms.

According to the study results, the MICs of TiO2 NPs were found to be 1.489, 1.208, and 1.166 mg/ mL for Escherichia coli, Pseudomonas aeruginosa, and Klebsiella pneumoniae as the Gram-negative bacteria, respectively; and they were discovered to be 0.512, 0.830, and 0.707 mg/mL for Streptococcus pneumoniae, Staphylococcus aureus, and Staphylococcus epidermidis as the Gram-positive bacteria, respectively. As for C. albicans, as the yeast strain, MIC was 0.253 mg/ mL. The MBIC of more than 90% of TiO2 NPs was 6.25 mg/mL for both Gram-negative and Gram-positive bacterial types and 1.562 mg/mL for C. albicans.

It was concluded that TiO2 NPs were effective antimicrobial agents for Gram-positive bacteria, Gram-negative bacteria, and C. albicans, but their inhibitory effect on yeast was greater than that of bacteria.

Klebsiella pneumoniae is one of the most important causes of opportunistic infections, including lobar pneumonia, urinary tract infection (UTIs), and wound infection. Treatment of disease caused by this bacterium has also become a challenge, as many strains are resistant to all β-lactam antibiotics. Metallo-β-lactamases hydrolyze most β-lactam antibiotics, especially carbapenems, but cannot inactivate monobactams. This study aimed to determine the prevalence of Metallo-β-lactamase genes (blaIMP, blaVIM, and blaNDM) in K. pneumoniae isolated from clinical specimens.

Clinical samples were collected from hospitals of Mazandaran province. Among 500 clinical samples collected, only 40 Klebsiella pneumoniae isolates were detected by culture and biochemical tests. Antimicrobial susceptibility testing was performed on all isolates by the Kirby-Bauer method. The polymerase chain reaction (PCR) technique was used for the identification of blaIMP, blaVIM, and blaNDM genes.

Antibiogram by disk diffusion method showed that 21 (52%) and 19 (48%) isolates were classified as imipenem resistant and sensitive, respectively. Of all the samples, 30 (75%), 7 (17.5%), and 36 (90%) contained blaVIM, blaIMP, and blaNDM genes, respectively. The co-existence of the blaVIM and blaNDM genes was observed in 22 (55%) isolates. The presence of both blaIMP and blaNDM genes was confirmed in 2 (5%) of the isolates. Four isolates (10%) had blaNDM, blaIMP, and blaVIM genes simultaneously, but none of these genes were present in one isolate (2.5%).

This study showed that the prevalence of metallo-β-lactamase genes in K. pneumoniae isolated from clinical specimens is very high, so it is recommended that physicians treat patients based on phenotypic and genotypic characteristics.

The growing spread of drug resistance in Helicobacter pylori has caused concern. Urease is one of the most important enzymes associated with H. pylori activity. Oxadiazoles have a wide range of inhibitory activities. The aim of this study was to investigate new oxadiazole compounds as urease inhibitors of H. pylori.

The synthesized compounds were reused as ligands in the previous study, and the initial structure of the compounds was optimized by the Molecular Mechanics Models method. Then, the compounds were evaluated as inhibitors on the active site of the urease enzyme by AutoDock Vina software, and the output results were analyzed and evaluated using soft Discovery Studio software.

All compounds, especially (4c) with flour groups, exhibited powerful inhibitory activity against the urease enzyme of H. pylori.

The present findings indicated the inhibitory potential of the novel synthetic 1, 3, 4-oxadiazole compounds.

Composites used in the direct bonding of brackets in fixed orthodontics are considered a suitable environment for the multiplication of cariogenic bacteria and the establishment of microbial plaques by creating a distance between the bracket, tooth surface, and surface properties such as porosity. In the present study, we decided to combine curcumin-reduced nano-graphene oxide (rGO-NCUR) with a composite resin used in orthodontics to achieve a composite with optimal shear bond strength (SBS) and antimicrobial properties against Streptococcus mutans as a main cariogenic bacterium.

In the present study, nanoparticle of graphene oxide (NGO) was synthesized by the modified Hummers’ method using graphite powder and reacted by NCUR to regenerate reduced-NGO (rGO-NCUR). Scanning electron microscopy (SEM) was used to confirm the synthesis of NGO, NCUR, and rGO-NCUR. SBS and antimicrobial activity of Transbond XT composite containing 5% rGO-NCUR were performed against S. mutans biofilms. SPSS software, one-way ANOVA test, and Tukey post hoc test with a significance level equal to or less than 0.05 were used to analyze the data.

The synthesis of NGO, NCUR, and rGO-NCUR in nanoscale was confirmed by SEM. The amount of SBS in the composite sample with 5% w/w rGO-NCUR was 12.30 ± 0.65 MPa. The optical density of S. mutans in the biofilm structure formed on composite containing 5% w/w rGO-NCUR was significantly reduced (62.10%) compared with the control group, namely, original composites used in orthodontics (P<0.05).

Based on the data of the present study, it can be concluded that composite containing 5% w/w rGO-CUR, without adverse effect on the physical-mechanical properties of composites, can be used as an antimicrobial additive of composites used in orthodontics to control biofilm formation and caries around orthodontic brackets.

Dental caries is one of the most common oral chronic diseases. Streptococcus mutans is the main pathogenic bacteria playing a role in degrading the mineral texture of the teeth. Glucosyltransferase (GTFase) of S. mutans is responsible for producing glucan, which is the main exopolysaccharide found in the cariogenic biofilms. Further, previous studies have reported that cinnamic acid diminished biofilm formation of S. mutans. Therefore, we hypothesized that cinnamic acid and its derivatives might act as GTFase inhibitors.

The binding affinity of a total of 12 plant-based compounds including cinnamic acid and its 11 derivatives to the GTFase active site were examined by utilizing the AutoDock tool. The possible interactions between top-ranked cinnamic acid derivatives and the residues within the GTFase catalytic site were also taken into consideration.

Five of the cinnamic acid derivatives including rosmarinic acid (RA), cynarine, chlorogenic acid (CGA), caffeic acid 3-glucoside, and N-p-coumaroyltyramine demonstrated inhibitory effects on GTFase at nanomolar concentration. Stabilizing interactions such as π–π stack pairing and pi-charge interactions were detected between top-ranked GTFase inhibitors and residues within the enzyme active site.

The present study suggests that RA, cynarine, CGA, caffeic acid 3-glucoside, and N-p-coumaroyltyramine might have protective effects on dental caries, and therefore, may be considered as anti-tooth caries compounds.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the cause of coronavirus disease 2019 (COVID-19) as a pandemic infectious disease which has led to thousands of deaths around the world. The Coronaviridae family is the second cause of the common cold that targets human respiratory tracts. Specific diagnostic laboratory tests in addition to clinical investigations would be helpful in confirming COVID-19 in the early stages for controlling the disease. Upon SARS-CoV-2 infection, antibody responses are produced during the early phase of illness (>7 days), meanwhile, viral nucleic acid real-time reverse-transcription polymerase chain reaction (rRT-PCR) test is applied as the confirmatory assay in the first 5-6 days after the onset of illness. Due to the rise of antibodies, the viral nucleic acid represents a gradual decline. These laboratory tests may be considered valuable for monitoring the patient’s status to prevent the spreading of infections and keep him/her in quarantine. The results of molecular and serological assays revealed that whether the person is recovered and protected against disease. Furthermore, regarding the rise of antibody titer and undetectable viral RNA, it may be possible to make a decision about when the recovered people could back to work and social life.

For the last three decades, the world population has experienced new epidemics of coronaviruses. The world is currently witnessing the novel coronavirus disease (COVID-19) epidemic, which is a disease that comes from a novel coronavirus called Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The available genetic and clinical proofs suggest a similar route to those of Middle East respiratory syndrome (MERS) and SARS. The clinical manifestations of infections caused by coronaviruses including SARS, MERS, and COVID-19 are pneumonia, bronchitis, or other serious respiratory infections. Various transmission ways (e.g., nosocomial transmission) and transmission through moderately symptomatic or non-symptomatic infected individuals have caused great concerns. Although no certain treatment has so far been developed for this disease, and prevention is the main applied strategy for these viruses, some medications can be used to help with this disease. Corticosteroids can be mentioned as an example of these medications. This article specifically reviewed the evidence regarding the effectiveness of the corticosteroid therapy for the coronavirus family (i.e., SARS, MERS, and COVID-19) and showed that there are insufficient data to recommend corticosteroid therapy for patients suffering from COVID-19.