Epidemiology of first- and second-line drugs-resistant pulmonary tuberculosis in Iran: Systematic review and meta-analysis

Drug resistance among Mycobacterium tuberculosis (MTB) strains is a growing concern in developing countries. We conducted a comprehensive search for relevant studies in Iran on PubMed, Scopus, and Embase until June 12, 2020. Our study focused on determining the prevalence of antibiotic resistance in MTB isolates, with subgroup analyses based on year, location, and drug susceptibility testing (DST) methods. Statistical analyses were performed using STATA software. Our meta-analysis included a total of 47 articles. Among new TB cases, we found the following prevalence rates: Any-resistance to first-line drugs: 31 % (95 % CI, 24-38), mono-drug resistance: 15 % (95 % CI, 10-22), and multidrug resistance to first-line drugs: 6 % (95 % CI, 4-8). There was a significant variation in the rate of MDR among new TB cases based on the year of publication, location, and DST methods (P < 0.0001). We observed substantial variability in multidrug-resistant TB rates among new cases across the studies. Stratified analyses revealed that publication years and DST methods significantly affected resistance rates. Studies from southern and central Iran reported higher any-drug resistance rates, suggesting regional differences. Among retreatment cases, the prevalence rates were as follows: Any resistance: 68 % (95 % CI 58-78), mono-resistance: 19 % (95 % CI 7-34), multidrug resistance: 28 % (95 % CI 15-43). Our study revealed that the prevalence of drug-resistant TB (DR-TB) among TB cases in Iran is higher than the global average. Particularly, MDR-TB among retreatment TB cases is a significant public health issue.

Aptasensor for ovarian cancer biomarker detection using nanostructured gold electrodes

The development of an electrochemical aptasensor for the detection of CA125 as an ovarian cancer biomarker using gold nanostructures (GNs) modified electrodes is reported. The GNs were deposited on the surface of fluorine-doped tin oxide electrodes using a simple electrochemical method and the effects of pH and surfactant concentration on the topography and electrochemical properties of the resulting GNs modified electrodes were investigated. The electrodes were characterized using field-emission scanning electron microscopy and X-ray diffraction, cyclic voltammetry, and electrochemical impedance spectroscopy. The best electrode, in terms of the uniformity of the deposited GNs and the increase in electroactive surface area, was used for development of an aptasensor for CA125 tumor marker detection in human serum. Signal amplification was done by using aptamer-conjugated gold nanorods resulting in the detection limit of 2.6 U/ml and a linear range of 10 to 800 U/ml. The results showed that without the need for expensive antibodies, the developed aptasensor could specifically measure the clinically relevant concentrations of the tumor marker in human serum.

The increasing antimicrobial resistance of Shigella species among Iranian pediatrics: a systematic review and meta-analysis

BACKGROUND

Shigellosis remains one of the global causes of morbidity and mortality. However, the global emergence of antibiotic resistance has become the leading cause of treatment failure in shigellosis. This review aimed to provide an updated picture of the antimicrobial resistance rates in Shigella species in Iranian pediatrics.

METHODS

A comprehensive systematic search was performed on PubMed, Scopus, Embase, and Web of Science until 28 July 2021. The meta-analysis was performed by computing the pooled using a random-effects model with Stata/SE software, v.17.1. The discrepancy within articles was surveyed by the forest plot in addition to the I2 statistic. All statistical interpretations were reported on a 95% confidence interval (CI) basis.

RESULTS

Totally, of 28 eligible studies published between 2008 and 2021. The pooled prevalence rate of multidrug-resistant (MDR) was 63% (95% CI 50-76). Regarding suggested antimicrobial agents for Shigella species, the prevalence of resistance for ciprofloxacin, azithromycin, and ceftriaxone as first- and second-line treatments for shigellosis were 3%, 30%, and 28%, respectively. In contrast, resistance to cefotaxime, cefixime, and ceftazidime was 39%, 35%, and 20%. Importantly, subgroup analyses indicated that an increase in resistance rates during the periods (2008-2014, 2015-2021) was recognized for ciprofloxacin (0 % to 6%) and ceftriaxone (6% to 42%).

CONCLUSION

Our findings revealed that ciprofloxacin is an effective drug for shigellosis in Iranian children. The substantially high prevalence estimation proposes that the first- and second-line treatments for shigellosis are the major threat to public health and active antibiotic treatment policies are essential.

Pulmonary radiologic findings based on Warrick score as a predictor of COVID-19 patients’ outcomes

Introduction: Predicting factors related to the severity and mortality of coronavirus disease 2019 (COVID-19) patients can significantly help in better management of their treatment. Objectives: This study aimed to investigate the correlation between pulmonary radiologic findings based on the Warrick score and COVID-19 patients’ outcomes. Patients and Methods: This descriptive-analytical study was conducted on 436 COVID-19 patients hospitalized at Shahid Mohammadi hospital in Bandar Abbas. Pulmonary radiologic findings were scored based on the Warrick score. Outcomes of COVID-19 patients, including disease severity and mortality, were followed. Independent T-test and binary logistic regression were conducted to explore the correlation between the pulmonary radiologic findings and patients’ outcomes. Results: Results showed that the correlation between pulmonary radiologic findings with both disease severity and mortality was significant, since higher pulmonary involvement caused greater severity and mortality. The Warrick score difference between dead and recovered patients and low and high disease severity were significant, therefore greater Warrick score caused more disease severity and mortality. Conclusion: Pulmonary radiologic findings based on the Warrick score can use as a predictor of COVID-19 patients’ outcomes.

Stable, reproducible, and binder-free gold/copper core-shell nanostructures for high-sensitive non-enzymatic glucose detection

The core-shell non-enzymatic glucose sensors are generally fabricated by chemical synthesis approaches followed by a binder-based immobilization process. Here, we have introduced a new approach to directly synthesis the core-shell of Au@Cu and its Au@Cu_xO oxides on an FTO electrode for non-enzymatic glucose detection. Physical vapor deposition of Au thin film followed by thermal annealing has been used to fabricate Au nanocores on the electrode. The Cu shells have been deposited selectively on the Au cores using an electrodeposition method. Additionally, Au@Cu₂O and Au@CuO have been synthesized via post thermal annealing of the Au@Cu electrode. This binder-free and selective-growing approach has the merit of high electrooxidation activity owing to improving electron transfer ability and providing more active sites on the surface. Electrochemical measurements indicate the superior activity of the Au@Cu₂O electrode for glucose oxidation. The high sensitivity of 1601 μAcm^-2 mM^-1 and a low detection limit of 0.6 μM are achieved for the superior electrode. Additionally, the sensor indicates remarkable reproducibility and supplies accurate results for glucose detection in human serums. Moreover, this synthesis approach can be used for fast, highly controllable and precise fabrication of many core-shell structures by adjusting the electrochemical deposition and thermal treatment parameters.

Seed-mediated Electrochemically Developed Au Nanostructures with Boosted Sensing Properties: An Implication for Non-enzymatic Glucose Detection

A new approach has been developed to improve sensing performances of electrochemically grown Au nanostructures (AuNSs) based on the pre-seeding of the electrode. The pre-seeding modification is simply carried out by vacuum thermal deposition of 5 nm thin film of Au on the substrate followed by thermal annealing at 500 °C. The electrochemical growth of AuNSs on the pre-seeded substrates leads to impressive electrochemical responses of the electrode owing to the seeding modification. The dependence of the morphology and the electrochemical properties of the AuNSs on various deposition potentials and times have been investigated. For the positive potentials, the pre-seeding leads to the growth of porous and hole-possess networks of AuNSs on the surface. For the negative potentials, AuNSs with carved stone ball shapes are produced. The superior electrode was achieved from AuNSs developed at 0.1 V for 900 s with pre-seeding modification. The sensing properties of the superior electrode toward glucose detection show a high sensitivity of 184.9 µA mM⁻¹ cm⁻², with a remarkable detection limit of 0.32 µM and a wide range of linearity. The excellent selectivity and reproducibility of the sensors propose the current approach as a large-scale production route for non-enzymatic glucose detection.

Rapid Simultaneous Molecular Stool-Based Detection of Toxigenic Clostridioides difficile by Quantitative TaqMan Real-Time PCR Assay

BACKGROUND

Clostridioides difficile is a major cause of nosocomial infectious diarrhea in hospitalized patients throughout the world.

METHODS

A multiplex real-time PCR assay was developed and evaluated in comparison with toxigenic culture (TC) (as gold standard method) for direct detection of toxigenic C. difficile in fecal specimens. The multiplex real-time PCR assay simultaneously detected glutamate dehydrogenase (gluD), toxin A (tcdA), toxin B (tcdB), and binary toxin (cdtB) genes in stool samples.

RESULTS

The results of multiplex real-time PCR were compared to those of the TC method in 250 patients suspected of C. difficile infection. The prevalence of positive TC was 13.6%. Forty-two stool samples (16.8%) were determined to be gluD+ using multiplex real-time PCR. These included 35 (83.3%) toxigenic (32 tcdA+, tcdB+ and three tcdB+) and 7 (20.0%) were cdtB+. The multiplex real-time PCR assay had a sensitivity of 91.45%, specificity of 99.54%, and positive and negative predictive values of 97% and 98.6%, respectively, compared to the TC method for diagnosis of C. difficile. The analytical sensitivity of the multiplex real-time PCR assay was estimated to be 102 CFU/g of stools and 0.0200 pg of genomic DNA from culture. The analytical specificity was determined to be 100% by using enteric and non-C. difficile standard bacterial strains.

CONCLUSIONS

The molecular method developed in the study was rapid, sensitive, and specific for detection of toxigenic C. difficile. It is applicable to be performed in clinical laboratories and correlated well with the results obtained by TC.

Fosfomycin: mechanisms and the increasing prevalence of resistance

There are challenges regarding increased global rates of microbial resistance and the emergence of new mechanisms that result in microorganisms becoming resistant to antimicrobial drugs. Fosfomycin is a broad-spectrum bactericidal antibiotic effective against Gram-negative and certain Gram-positive bacteria, such as Staphylococci, that interfere with cell wall synthesis. During the last 40 years, fosfomycin has been evaluated in a wide range of applications and fields. Although numerous studies have been done in this area, there remains limited information regarding the prevalence of resistance. Therefore, in this review, we focus on the available data concerning the mechanisms and increasing resistance regarding fosfomycin.

The diversity of class B and class D carbapenemases in clinical Acinetobacter baumannii isolates

Wide distrubution of multidrug-resistant Acinetobacter baumannii strains has become a foremost concern in hospital environments. Treatment of infections caused by multidrug resistant strains has conventionally involved the use of β-lactams such as carbapenems. In this study, we report the distribution of carbapenemase genes in A. baumannii isolated from hospitalized patients. The study was conducted on 110 non-repetitive A. baumannii isolates collected from hospitalized patients, over a nine-month period. Clinical isolates were examined by conventional susceptibility testing, using the disk-diffusion method and multiplex polymerase chain reaction to detect acquired carbapenemase genes. All of the isolates were completely resistant to TOB, SXT, IPM, MEM, CTX, CRO, FEP, CAZ, CIP, PTZ, PIP and were susceptible to colistin, but moderately susceptible TET (2.72%), AK (4.54%) and GEN (3.63%). The prevalence of bla-OXA-51like, bla-OXA-23like, bla-OXA-24like, bla-OXA-58like, blaSIM and blaSPM genes was 100%, 96.36%, 35.45%, 7.27%, 7.27% and 3.63%, respectively. bla-GIM and bla-VIM genes were not detected among the strains. Our results suggest that OXA-type carbapenemase genes plus class B β-lactamases contribute to carbapenem resistance in the collected isolates. Therefore, quick identification of these resistant genes using molecular approaches is critical in limiting the spread of infections caused by A. baumannii. Drug administration correction of the physicians, based on antibiotic susceptibility testing and more knowledge on the nosocomial infection control policies as essential need.

Genotypic characterization of Staphylococcus aureus isolated from a burn centre by using agr, spa and SCCmec typing methods

Infections caused by Staphylococcus aureus remain a major global healthcare problem. We aimed to find the common lineages of S. aureus strains circulating in a burn hospital in Tehran. A total of 167 isolates of S. aureus obtained from patients, healthcare workers (HCWs) and environment in Shahid Motahari burn hospital were genotyped by using spa, agr and staphylococcal cassette chromosome mec (SCCmec) typing methods. Antimicrobial susceptibility testing was performed by using the disc diffusion method. The frequency of methicillin-resistant S. aureus (MRSA) was 64.7% (n = 108), with distribution frequencies among patient, HCW and surface isolates of 64.2% (n = 79), 50% (n = 7) and 73.3% (n = 22), respectively. SCCmec type III (75%, n = 81) was found to be the most frequent SCCmec type among MRSA isolates, followed by SCCmec type I (20.4%, n = 22) and SCCmec type IV (1.8%, n = 2). The remaining MRSA isolates (2.8%, n = 3) were nontypeable by this method. About 78.4% (n = 131), 10.2% (n = 17) and 4.8% (n = 8) of all isolates were characterized as agr types I, II and III, respectively, and the other isolates (6.6%) were nontypeable. spa types t030 and t037 constituted the first and second most predominant spa types found in 56.4% (n = 57) and 25.6% (n = 26) of isolates, respectively. We also report here a novel spa type, t16471. The most prevalent genotypes of the isolates found among patient, surface and HCW samples were SCCmec type III/t030, t037/agr type I. Continuous tracking of epidemic isolates and better hospital infection control policies are recommended to efficiently prevent the spread of bacteria to inpatients.

Mechanism of adsorption of single and double stranded DNA on gold and silver nanoparticles: Investigating some important parameters in bio-sensing applications

The mechanism of adsorption of single and double stranded DNAs on colloidal gold and silver nanoparticles has been studied by measuring the resistance of the nanoparticles, surrounded by various oligonucleotides, against salt induced aggregation. It is shown that both single and double stranded DNAs can be adsorbed on the metal nanoparticles and the adsorption strength is determined by the interaction between various bases of DNA and the nanoparticles. By changing the salt concentration, the difference between adsorption of various DNA strands on the nanoparticles can be specified. The results indicate that a key parameter in success of a sensing assay of DNA hybridization is the salt concentration which should be greater than a minimum threshold depending on the nanoparticles characteristics. We have also investigated the interaction mechanism between various DNA bases with the metal nanoparticles. For both gold and silver nanoparticles, adenine has the highest and thymine has the lowest attachment to the nanoparticles. From surface enhanced Raman spectroscopy (SERS) data of various bases in the presence of gold nanoparticles, the probable interaction points in the bases with the nanoparticles have been determined, which are mainly the nitrogen sites of these oligonucleotides.

Effect of thyroid dysfunctions on blood cell count and red blood cell indice

BACKGROUND

Thyroid hormones have a crucial role in metabolism and proliferation of blood cells. Thyroid dysfunction induces different effects on blood cells such as anemia, erythrocytosis leukopenia, thrombocytopenia, and in rare cases causes' pancytopenia. It also alter RBC indices include MCV, MCH, MCHC and RDW. Thus this study attempted to evaluate effect of hypo & hyperthyroidism on blood cell count and RBC indices.

MATERIALS AND METHODS

This study performed on 102 patients with hypothyroid (14.1 years), 84 with hyperthyroid (15.6 years) and 118 healthy individuals (15.2 years) as control group. Initially patients TSH level of patients was determined by ELISA method, and then according to TSH ranges (0.3-5.5µIU/mL) patients were divided into two Hyperthyroidism (TSH<0.3µIU/mL) and hypothyroidism (TSH>5.5µIU/mL) groups. Then, complete blood count was measured by cell counter. Finally, obtained results were analyzed by SPSS software.

RESULTS

Analyzes of obtained data revealed statistically significant difference between two groups of patients in RBC count, MCH, MCHC, RDW, HB and HCT(P-value<0.05), but the difference was not significant for WBC and PLT counts and MCV (P-value>0.05).

CONCLUSION

In case of patients with unknown hematological dysfunctions, must be evaluated for thyroid hormones.