Antimicrobial combination effects against multidrug-resistant Acinetobacter baumannii and Pseudomonas aeruginosa strains: A cross-sectional study.

Background and Aims: Emergence of multidrug resistance in non-fermenting Gram-negative bacilli is a threat to public health. Combination therapy is a strategy for the treatment of antibiotic-resistant infections. Methods: In this cross-sectional study, a total of 63 nonduplicate clinical isolates of Acinetobacter baumannii and Pseudomonas aeruginosa were collected from various specimens. Identification of bacterial isolates was performed by phenotypic and molecular tests. Antibiotic susceptibility patterns and detection of ß-lactamase genes were determined using the broth microdilution and polymerase chain reaction (PCR) techniques, respectively. Then, the combined effects analysis was determined by the checkerboard method. Based on the status of resistance to carbapenems (imipenem and meropenem), 25 isolates of each genus were selected for further investigation. Results: For A. baumannii, bla OXA-23, bla OXA-58, and bla OXA-48 genes were positive in 21 (84%), 17 (68%), and 11 (44%) of isolates, respectively. In P. aeruginosa isolates, bla VIM was the most common gene (44%) and other genes including bla IMP, bla NDM, and bla OXA-23 were found in nine (36%), six (24%), and three (12%) isolates, respectively. Meropenem (MER)-tigecycline (TIG) had a significant synergistic effect against 20 (80%) A. baumannii (p value < 0.001). This combination was also efficient against 5 (20%) P. aeruginosa isolates. Moreover, the other combination, tigecycline-amikacin (TIG-AMK) was effective against 10 (40%) A. baumannii isolates. The combination of colistin (COL) and MER showed a significant synergistic effect against 21 (84%) A. baumannii (p value < 0.001) and 17 (68%) P. aeruginosa isolates (p value < 0.001). Conclusion: The MER-TIG and COL-MER combinations are promising options against resistant bacteria. Our study could be helpful for the development of a new treatment recommendation.

Effects of non-tuberculous mycobacteria on BCG vaccine efficacy: A narrative review.

The Mycobacterium tuberculosis bacterial pathogen is responsible for the ongoing global tuberculosis (TB) epidemic. Bacille Calmette-Guérin (BCG), the only currently approved TB vaccine, is successful in preventing disseminated disease in newborns. However, it has a variable efficacy against pulmonary TB in adults. This protective effect of the vaccine varies greatly among different populations and geographical areas, which the increased exposure of particular populations to non-tuberculous mycobacteria (NTM) is considered as one of the reasons for this issue. Numerous studies have shown that exposure to NTM species causes the host immune system to be improperly primed. It has also been suggested that NTM species may be blamed for reduction in BCG vaccine effectiveness against M. tuberculosis. The increased exposure of certain populations to NTM has diverse effects on BCG efficacy. Moreover, the exposure to NTM can induce opposite effects on BCG efficacy depending on the NTM exposure route and survivability. A detailed understanding of the impact of NTM exposure on the efficacy of the BCG vaccine is essential for ongoing efforts to develop new TB vaccines as it may ultimately be a crucial success factor. The aim of this study was to review the findings of the studies focusing on the effects of NTM on BCG vaccine efficacy in animal models.

Enhanced adsorption of toluene on thermally activated ZIF-67: Characterization, performance, and modeling insights.

The zeolitic imidazolate framework-67 (ZIF-67) has been explored for the dynamic adsorption of toluene vapor. We synthesized ZIF-67 through a straightforward room-temperature process and characterized it using XRD, FT-IR, DLS, and SEM techniques. The synthesized ZIF-67 possessed a Brunauer-Emmett-Teller (BET) surface area of 1578.7 m2/g and 0.76 µm particle size. Thermal activation under various conditions revealed that ZIF-67, activated in dry air at 250 °C, demonstrated optimal adsorption efficacy. Its adsorption capacity, time of breakthrough, and time of equilibration were 414.5 mg/g, 420 min, and 795 min, respectively. We investigated the impact of diverse operational parameters on adsorption through breakthrough curve analysis. An increase in the toluene concentration from 100 to 1000 ppm enhanced the adsorption capacity from 171 to 414 mg/g, while breakthrough time decreased from 1260 min to 462 min, respectively. Our findings show that increasing relative humidity from 0 to 70 % reduced 53.7 % in adsorption capacity and 46.3 % in breakthrough time. The competitive adsorption of toluene and ethylbenzene revealed that ZIF-67 had a higher selectivity for toluene adsorption. A 98 % adsorbent's regeneration efficiency at the first cycle reveals its reusability. The experimental data were successfully fitted to the Yan, Thomas, and Yoon-Nelson models to describe the adsorption process. The statistical validation of the model parameters confirms their reliability for estimating adsorption parameters, thus facilitating the design of fixed-bed adsorption columns for practical applications.

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.

Efficient removal of microcystin-LR from contaminated water using water-stable MIL-100(Fe) synthesized under HF-free conditions.

Cyanobacterial algal hepatotoxins, called microcystins (MCs), are a global health concern, necessitating research on effective removal methods from contaminated water bodies. In this study, we synthesized non-fluorine MIL-100(Fe) using an environmentally friendly room-temperature method and utilized it as an adsorbent to effectively remove microcystin-LR (MC-LR), which is the most toxic MC congener. MIL-100(Fe) was thoroughly characterized, and its adsorption process was investigated under various conditions. Results revealed rapid MC-LR adsorption, achieving 93% removal in just 5 min, with the pseudo-second-order kinetic model indicating chemisorption as the primary mechanism. The Langmuir isotherm model demonstrated a monolayer sorption capacity of 232.6 µg g-1 at room temperature, showing favorable adsorption. Furthermore, the adsorption capacity increased from 183 µg g-1 at 20 °C to 311 µg g-1 at 40 °C, indicating an endothermic process. Thermodynamic parameters supported MC-LR adsorption's spontaneous and feasible nature onto MIL-100(Fe). This study highlights MIL-100(Fe) as a promising method for effectively removing harmful biological pollutants, such as MC-LR, from contaminated water bodies in an environmentally friendly manner.

Advancements in combined electrocoagulation processes for sustainable wastewater treatment: A comprehensive review of mechanisms, performance, and emerging applications.

This review explores the potential and challenges of combining electrochemical, especially electrocoagulation (EC) process, with various - wastewater treatment methods such as membranes, chemical treatments, biological methods, and oxidation processes to enhance pollutant removal and reduce costs. It emphasizes the advantages of using electrochemical processes as a pretreatment step, including increased volume and improved quality of permeate water, mitigation of membrane fouling, and lower environmental impact. Pilot-scale studies are discussed to validate the effectiveness of combined EC processes, particularly for industrial wastewater. Factors such as electrode materials, coating materials, and the integration of a third process are discussed as potential avenues for improving the environmental sustainability and cost-effectiveness of the combined EC processes. This review also discusses factors for improvement and explores the EC process combined with Advanced Oxidation Processes (AOP). The conclusion highlights the need for combined EC processes, which include reducing electrode consumption, evaluating energy efficiency, and conducting pilot-scale investigations under continuous flow conditions. Furthermore, it emphasizes future research on electrode materials and technology commercialization. Overall, this review underscores the importance of combined EC processes in meeting the demand for clean water resources and emphasizes the need for further optimization and implementation in industrial applications.

Unlocking the potential of Tunisian dam sediment: optimizing zeolite X synthesis via Taguchi and Box-Behnken methods for sustainable resource recovery and versatile applications.

The Tunisian Lebna dam sediment was utilized to create the zeolite faujasite type Na-X. The aim of this investigation is to optimize the yield of Na-X zeolite using alkaline fusion hydrothermal treatment. Taguchi orthogonal array design was employed with nine trials to explore operating parameters including fusion temperature and time, activator type, and sediment type. The efficiency of alkaline fusion was evaluated using acid solubility. After dissolving the optimal alkali-fused sample in water, the Box-Behnken plan was used to identify the influence of L/S ratio, crystallization temperature, and time on zeolite Na-X yield. Rietveld analysis identified the mineral phases in the sediment as quartz (82.0%), calcite (8.8%), kaolinite (6.0), and illite (1.2%). With a NaOH activator, 850 °C fusion temperature for 30 min, 15 L/S ratio, and 75 °C crystallization temperature for 4 days, highly crystalline zeolite Na-X was created. FTIR, TGA, N2 adsorption-desorption isotherm, and X-ray diffraction were used to thoroughly describe this sample. The findings reveal the substantial zeolitization potential of the raw Lebna dam sediment, resulting in a high yield of zeolite Na-X.

Trends in the Antibiotic Resistance of Non-Tuberculous Mycobacteria in Iran: A Systematic Review and Meta-Analysis.

Background: Non-tuberculous mycobacteria (NTM) infections have been continuously increasing as major concerns of public health in Iran. Because innate resistance of NTM species, the treatment of these infections is difficult task, but until now resistance pattern of NTM and suitable regimens are not determined. Methods: We systematically searched the relevant studies in PubMed, Scopus, and Embase (Until Dec 2022). All statistical analyses were carried out using the statistical package R. Results: Eleven studies included in the analysis were performed in 6 provinces and investigated 1223 NTM clinical species. The majority of the studies originated in Tehran. Among the first-line anti-TB drugs, almost all NTM species were highly resistant to first-line anti-TB drugs. No significant difference in the isoniazid resistance rate was found in the slow or rapid-growing species and Runyon's classification of NTM isolates. A decreased in the prevalence of ciprofloxacin, clarithromycin, and moxifloxacin resistance were showed in during 2013-2022 years. Conclusion: Most investigated antibiotics have a minor effect on NTM species and a steady increase of resistance has been seen in last few years then, need more-effective alternative regimens is clear.

Detection of qacΔE Efflux Pump Gene among the Clinical Isolates of Escherichia coli and its Correlation with Resistance to Disinfectants.

BACKGROUND: Disinfectants and antiseptics inhibit the dissemination of pathogenic organisms in hospitals but often cause disinfectant-resistant microorganisms, an important factor for nosocomial infection. This study aimed to evaluate the correlation between qacΔE efflux pump gene and its resistance to disinfectants among Escherichia coli clinical isolates. METHODS: A total of 97 E. coli isolates were isolated from patients with urinary tract infections. The minimum inhibition concentration (MIC) value of chlorhexidine and benzalkonium chloride was determined using broth microdilution method. Effect of efflux pumps was assessed by MIC test in the presence of phenylalanine-arginine ß-naphthylamide (PAßN), and then the qacΔE efflux pump gene was detected using polymerase chain reaction (PCR). RESULT: Of the isolates, 85.6% and 61.9% were resistant to chlorhexidine and benzalkonium chloride, respectively. Following the treatment of isolates with the efflux pump's inhibitor, PAßN, the MIC value of chlorhexidine and benzalkonium chloride decreased in 75.2% and 57.7% of the isolates, respectively. A significant correlation was found between PAßN treatment and the change in the resistant strains to susceptible strains (p = 0.021). The qacΔE gene was detected in 84.5% (n = 82) of the isolates, and the presence of the gene amongst disinfectant-resistant strains was also significant (p < 0.001). CONCLUSIONS: It is suggested to conduct other studies on other efflux pumps, as well as to periodically monitor the resistance to disinfectants. Substances inhibiting efflux pumps and neutral compounds are effective in the reduction of resistance to disinfectants. New disinfectants and drugs should be designed.

Facile and innovative application of surfactant-modified-zeolite from Austrian fly ash for glyphosate removal from water solution.

This study highlights a pioneering approach in the development of an efficient, affordable, and economically feasible adsorbent specifically tailored for the removal of glyphosate (Gly) from contaminated water. To accomplish this objective, a low-cost and pure NaA Zeolite (NaAZ) was synthesized with 93% crystallinity from Austrian fly ash (AFA) as a precursor for the first-time. Taguchi design was employed to optimize critical parameters such as the SiO2/Al2O3 ratio, alkalinity concentration, time, and temperature. The cation exchange capacity (CEC) and external cation exchange capacity (ECEC) are determined as critical factors for the modification process. Subsequently, the pure NaAZ was modified with hexadecyl trimethyl ammonium chloride (HDTMAC), a cationic surfactant. The utilization of surfactant-modified zeolite (SMZ) for Gly removal demonstrates its innovative application in this field, highlighting its enhanced adsorption capacity and optimized surface properties. The AFA, NaAZ, and SMZ were characterized using analytical techniques including XRD, XRF, FTIR-ATR, SEM, TGA, BET, CHNSO analyzer and ICP-OES. The adsorbent exhibited effective Gly removal through its pH-dependent charge properties (pH 2-10), with an optimized pH 6 facilitating a significant electrostatic interaction between the adsorbent and Gly. SMZ demonstrated remarkable adsorption capacity and removal efficacy, surpassing most reported adsorbents with values of 769.23 mg/g and 98.92% respectively. Our study demonstrates the significant advantage of the SMZ, with a low leaching concentration of only 6 ppm after 60 days, ensuring environmental safety, long-term stability, and public health considerations. The kinetics of the adsorption process was well described by the pseudo-second order and the Freundlich isotherm. Pore diffusion and H-bonding were postulated to be involved in physisorption, whereas electrophilic interactions led to chemisorption type of adsorption. Consequently, SMZ provides a practical significance, broad applicability and promising solution for Gly removal, facilitating sustainable water treatment.

Aptamer-modified metal organic frameworks for measurement of food contaminants: a review.

The measurement of food contaminants faces a great challenge owing to the increasing demand for safe food, increasing consumption of fast food, and rapidly changing patterns of human consumption. As different types of contaminants in food products can pose different levels of threat to human health, it is desirable to develop specific and rapid methods for their identification and quantification. During the past few years, metal-organic framework (MOF)-based materials have been extensively explored in the development of food safety sensors. MOFs are porous crystalline materials with tunable composition, dynamic porosity, and facile surface functionalization. The construction of high-performance biosensors for a range of applications (e.g., food safety, environmental monitoring, and biochemical diagnostics) can thus be promoted through the synergistic combination of MOFs with aptamers. Accordingly, this review article delineates recent innovations achieved for the aptamer-functionalized MOFs toward the detection of food contaminants. First, we describe the basic concepts involved in the detection of food contaminants in terms of the advantages and disadvantages of the commonly used analytical methods (e.g., DNA-based methods (PCR/real-time PCR/multiplex PCR/digital PCR) and protein-based methods (enzyme-linked immunosorbent assay/immunochromatography assay/immunosensor/mass spectrometry). Afterward, the progress in aptamer-functionalized MOF biosensors is discussed with respect to the sensing mechanisms (e.g., the role of MOFs as signal probes and carriers for loading signal probes) along with their performance evaluation (e.g., in terms of sensitivity). We finally discuss challenges and opportunities associated with the development of aptamer-functionalized MOFs for the measurement of food contaminants.

The global prevalence of gastric cancer in Helicobacter pylori-infected individuals: a systematic review and meta-analysis.

BACKGROUND: Helicobacter pylori is a gastrointestinal pathogen that infects around half of the world's population. H. pylori infection is the most severe known risk factor for gastric cancer (GC), which is the second highest cause of cancer-related deaths globally. We conducted a systematic review and meta-analysis to assess the global prevalence of GC in H. pylori-infected individuals. METHODS: We performed a systematic search of the PubMed, Web of Science, and Embase databases for studies of the prevalence of GC in H. pylori-infected individuals published from 1 January 2011 to 20 April 2021. Metaprop package were used to calculate the pooled prevalence with 95% confidence interval. Random-effects model was applied to estimate the pooled prevalence. We also quantified it with the I2 index. Based on the Higgins classification approach, I2 values above 0.7 were determined as high heterogeneity. RESULTS: Among 17,438 reports screened, we assessed 1053 full-text articles for eligibility; 149 were included in the final analysis, comprising data from 32 countries. The highest and lowest prevalence was observed in America (pooled prevalence: 18.06%; 95% CI: 16.48 - 19.63; I2: 98.84%) and Africa (pooled prevalence: 9.52%; 95% CI: 5.92 - 13.12; I2: 88.39%). Among individual countries, Japan had the highest pooled prevalence of GC in H. pylori positive patients (Prevalence: 90.90%:95% CI: 83.61-95.14), whereas Sweden had the lowest prevalence (Prevalence: 0.07%; 95% CI: 0.06-0.09). The highest and lowest prevalence was observed in prospective case series (pooled prevalence: 23.13%; 95% CI: 20.41 - 25.85; I2: 97.70%) and retrospective cohort (pooled prevalence: 1.17%; 95% CI: 0.55 - 1.78; I 2: 0.10%). CONCLUSIONS: H. pylori infection in GC patients varied between regions in this systematic review and meta-analysis. We observed that large amounts of GCs in developed countries are associated with H. pylori. Using these data, regional initiatives can be taken to prevent and eradicate H. pylori worldwide, thus reducing its complications.

Study on phosphate removal from aqueous solutions using magnesium-ammonium- and zirconium-modified zeolites: equilibrium, kinetic, and fixed-bed column study.

Eutrophication is an environmental issue which occurs when the environment becomes enriched with nutrients. Phosphorus (P) is a key nutrient limiting the phytoplankton and algal growth in many aquatic environments. Therefore, P removal could be a promising technique to control the eutrophication. Herein, a natural zeolite (NZ) was modified by two practical techniques, including zirconium (ZrMZ) and magnesium-ammonium modification (MNZ), and employed for phosphate removal. Batch, equilibrium, and column experiments were conducted to determine various adsorption parameters. Equilibrium data were fitted to two different isotherms and Freundlich isotherm provided the best fit which confirms multi-layer adsorption of phosphate ions on the adsorbents. The kinetic experiments demonstrated that the adsorption process is fast with more than 80% of phosphate adsorbed in the first 4 h, and a subsequent equilibrium was established after 16 h. The kinetic data were well described by pseudo-second-order model, suggesting that chemisorption is the mechanism of sorption. Intraparticle diffusion showed a rate-limiting step for phosphate adsorption on all the adsorbents, especially MNZ and ZrMZ. The fixed-bed column study showed that the phosphate concentration in the outlet (C) of ZrMZ column did not reach the initial concentration (C0) after passing 250 bed volume (BV), while it reached C0 after 100 BV when the MNZ was employed. Given the considerable improvement were seen, the results of this study suggest that surface of zeolite can be modified with zirconium (and in a less extent magnesium-ammonium) to enhance adsorption of phosphate from many eutrophic lakes.

Global status of phenotypic pyrazinamide resistance in Mycobacterium tuberculosis clinical isolates: an updated systematic review and meta-analysis.

Pyrazinamide (PZA) is an essential first-line tuberculosis drug for its unique mechanism of action active against multidrug-resistant-TB (MDR-TB). Thus, the aim of updated meta-analysis was to estimate the PZA weighted pooled resistance (WPR) rate in M. tuberculosis isolates based on publication date and WHO regions. We systematically searched the related reports in PubMed, Scopus, and Embase (from January 2015 to July 2022). Statistical analyses were performed using STATA software. The 115 final reports in the analysis investigated phenotypic PZA resistance data. The WPR of PZA was 57% (95% CI 48-65%) in MDR-TB cases. According to the WHO regions, the higher WPRs of PZA were reported in the Western Pacific (32%; 95% CI 18-46%), South East Asian region (37%; 95% CI 31-43%), and the Eastern Mediterranean (78%; 95% CI 54-95%) among any-TB patients, high risk of MDR-TB patients, and MDR-TB patients, respectively. A negligible increase in the rate of PZA resistance were showed in MDR-TB cases (55% to 58%). The rate of PZA resistance has been rising in recent years among MDR-TB cases, underlines the essential for both standard and novel drug regimens development.

Nosocomial infections and antimicrobial susceptibility patterns among patients admitted to intensive care unit of Imam Khomeini hospital in Ilam, Iran.

INTRODUCTION: Nosocomial infections (NIs) are a major challenge worldwide. Identification of antibiotic resistance pattern extended spectrum beta-lactamases (ESBLs) and carbapenem-resistant Enterobacteriaceae (CRE) were the objectives of this study. METHODS: In this cross-sectional study, the antimicrobial susceptibility pattern of bacterial isolates collected from patients with NIs in ICU was determined. Overall, 42 Escherichia coli and Klebsiella pneumoniae isolates from different infection sites were used to determine phenotypic tests of ESBLs, Metallo-ß-lactamases (MBLs) and CRE. Detection of ESBLs, MBLs and CRE genes were performed by the polymerase chain reaction (PCR) method. RESULTS: From 71 patients with NIs, 103 different bacterial strains were isolated. The most frequently isolated bacteria were E. coli (n = 29; 28.16%), Acinetobacter baumannii (n = 15; 14.56%), and K. pneumoniae (n = 13; 12.26%). Also, the rate of multidrug-resistant (MDR) isolates was 58.25% (60/103). Based on phenotypic confirmation tests, 32 (76.19%) isolates of E. coli and K. pneumoniae produced ESBLs, and 6 (14.28%) isolates were identified as CRE producers. PCR showed the high prevalence of the blaCTX-M (n = 29; 90.62%) in ESBL genes. In addition, blaNDM was detected in 4 (66.66%), blaOXA-23 in 3 (50%), and blaOXA-48 gene in 1 (16.66%) isolates. The blaVIM, blaKPC, and blaIMP genes were not detected in any of the isolates. CONCLUSION: The Gram-negative bacteria E. coli, A. baumannii, and K. pneumoniae with high resistance levels were the most common bacteria causing NIs in the ICU. This study for the first time identified blaOXA-11, blaOXA-23, and blaNDM-1 genes in E. coli and K. pneumoniae in Ilam city of Iran.

Green and facile synthesis of lignin/HKUST-1 as a novel hybrid biopolymer metal-organic-framework for a pH-controlled drug release system.

This manuscript describes the synthesis and characterization of a hybrid polymer/HKUST-1 composite for oral drug delivery. A green, one-pot approach was employed to synthesize the modified metal-organic frameworks (MOFs) composite using alkali lignin as a novel pH-responsive biopolymer carrier for the simulated oral delivery system. Several analytical techniques, including Fourier transform infrared (FTIR), X-ray powder diffraction (XRPD), Brunauer-Emmett-Teller (BET), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM) were used to analyze the chemical and crystalline structure of HKUST-1 and L/HKUST-1 composite. The drug loading capacity and drug-controlled release behavior of HKUST-1 and L/HKUST-1 were examined using ibuprofen (IBU) as an oral drug model. L/HKUST-1 composite demonstrated a pH-controlled drug release behavior by advancing the drug stability at low pHs such as the gastric medium and controlling drug release in the pH range of 6.8-7.4, similar to intestinal pH. The results suggest that the L/HKUST-1 composite is a promising candidate for oral medication delivery.

Characterization of the short-term temporal variability of road dust chemical mixtures and meteorological profiles in a near-road urban site in British Columbia.

Implications: Non-tailpipe emissions driven by springtime road dust in northern latitude communities is increasing in importance for air pollution control and improving our understanding of the health effects of chemical mixtures from particulate matter exposure. High-volume samples from a near-road site indicated that days affected by springtime road dust are substantively different from other days with respect to particulate matter mixture composition and meteorological drivers. The high load of trace elements in PM10 on high road dust days has important implications for the acute toxicity of inhaled air and subsequent health effects. The complex relationships between road dust and weather identified in this study may facilitate further research on the health effects of chemical mixtures related to road dust while also highlighting potential changes in this unique form of air pollution as the climate changes.

Molecular characterizations of antibiotic resistance, biofilm formation, and virulence determinants of Pseudomonas aeruginosa isolated from burn wound infection.

BACKGROUND: Burn injuries result in disruption of the skin barrier against opportunistic infections. Pseudomonas aeruginosa is one of the main infectious agents colonizing burn wounds and making severe infections. Biofilm production and other virulence factors along with antibiotic resistance limit appropriate treatment options and time. MATERIALS AND METHODS: Wound samples were collected from hospitalized burn patients. P. aeruginosa isolates and related virulence factors identified by the standard biochemical and molecular methods. Antibiotic resistance patterns were determined by the disc diffusion method and ß-lactamase genes were detected by polymerase chain reaction (PCR) assay. To determine the genetic relatedness amongst the isolates, enterobacterial repetitive intergenic consensus (ERIC)-PCR was also performed. RESULTS: Forty P. aeruginosa isolates were identified. All of these isolates were biofilm producers. Carbapenem resistance was detected in 40% of the isolates, and blaTEM (37/5%), blaVIM (30%), and blaCTX-M (20%) were the most common ß-lactamase genes. The highest resistance was detected to cefotaxime, ceftazidime, meropenem, imipenem and piperacillin, and 16 (40%) isolates were resistant to these antibiotics. The minimum inhibitory concentrations (MIC) of colistin was lower than 2 µg/mL and no resistance was observed. Isolates were categorized to 17 MDR, 13 mono-drug resistance, and 10 susceptible isolates. High genetic diversity was also observed among the isolates (28 ERIC types) and most carbapenem-resistant isolates were classified into four main types. CONCLUSION: Antibiotic resistance, particularly carbapenem resistance was considerable among the P. aeruginosa isolates colonizing burn wounds. Combining carbapenem resistance with biofilm production and virulence factors would result in severe and difficult-to-treat infections.

Molecular Characterization of Resistance to Second-Line Anti-Mycobacterial Drugs among Clinical Isolates of Multidrug-Resistant Mycobacterium tuberculosis.

BACKGROUND: The emergence of multidrug resistance and extensively drug-resistant tuberculosis is a serious public health crisis. Using rapid and inexpensive molecular methods such as HRM assay in the detection of second-line drugs resistance in M. tuberculosis would be helpful in the treatment and control of XDR tuberculosis cases. METHODS: MDR-TB isolates were collected from Iranian tuberculosis laboratories. Drug susceptibility test performed via the indirect proportion method utilizing LJ Medium. Susceptibility to ciprofloxacin, ofloxacin, amikacin, kanamycin, and capreomycin, as second-line anti-tuberculosis agents were assessed. Single point mutations in gyrA, rrs and eis genes were detected via HRM assay and DNA sequencing. RESULTS: A DST test was performed for 56 MDR isolates and at least 27 (48.2%) isolates were resistant to CIP or OFL. Also, 14 (25%), 12 (21.4%), and 15 (26.7%) isolates were resistant to capreomycin, amikacin, and kanamycin, respectively. D94G, A90V, and G88C mutations were the most frequent mutations in gyrA gene. Also, A1401G mutation was detected more than the other mutations in rrs gene. CONCLUSIONS: The frequency of CIP/OFL and AMK/CAP/KAN-resistant TB is considerable among Iranian tuberculosis cases. HRM assay is a rapid and inexpensive test and can detect important mutation-based drug resistance in MDR-TB and XDR-TB isolates.

N, P, K recovery from hydrolysed urine by Na-chabazite adsorption integrated with ammonia stripping and (K-)struvite precipitation.

This study investigated the recovery of K+ along with NH4+-N and PO43--P from hydrolyzed urine by technical integration. The K adsorption capacities of biochar, clinoptilolite, artificial zeolite and chabazite were firstly compared. Due to the high K recovery efficiency and additional P recovery capacity, Na-chabazite was selected as the adsorbent in this study. Its kinetics and isotherm analysis indicated that the high molarity of NH4+-N seriously hindered the K adsorption onto Na-chabazite in synthetic hydrolyzed urine (SHU). However, this competition between NH4+ and K+ got diminished when their molarity is the same, i.e. in the SHU after ammonia stripping (ASSHU). Based on this key finding, Na-chabazite adsorption was integrated with ammonia stripping and struvite precipitation under different configurations. Simultaneous ammonia stripping was inadequate to diminish the competitive effect of NH4+ on K+ adsorption. Depending on the demand for fertilizer, two sequential configurations were recommended, respectively.