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Burn wounds are vulnerable to various infections due to damage to the tissue and changes in immune responses. Pseudomonas aeruginosa is a critical bacterium that can cause burn wound infections, which can be life-threatening and delay wound healing. Therefore, it is essential to develop an efficient strategy to prevent the spread of infection in burn wounds. The present study aims to investigate the effectiveness of electrospun nanofibers of royal jelly on a chitosan/polyvinyl alcohol polymer scaffold in repairing burn wounds infected with Pseudomonas aeruginosa. To achieve this, the researchers analyzed the morphology and physicochemical properties of the synthesized nanofibers using SEM, FTIR, BET, and TGA analyses. They also examined the antibacterial properties of the nanofibers using agar diffusion and spread plate techniques. In addition, hemolysis tests were carried out to assess biocompatibility. Finally, the ability of the nanofibers to repair burn wounds infected with Pseudomonas aeruginosa was evaluated using a laboratory mouse model. The study results showed that the synthesized nanofibers had desirable morphology and physicochemical properties and significant antibacterial effects in both in vitro and in vivo conditions. Also, loading RJ into the polymer scaffold significantly reduced erythrocyte lysis. The wound healing and contraction rates were significantly higher than the control groups, and tissue repair, re-epithelialization, and collagen synthesis occurred faster, preventing the spread of infection to deeper tissue areas. Based on these findings, the synthesized system has the potential to serve as a suitable substitute for some invasive treatments and chemical drugs to improve chronic wounds and manage infection control in burn injuries., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Carbapenems are the most important therapeutic options that effect against serious infections caused by multidrug resistant Pseudomonas aeruginosa (MDR-PA) isolates. Carbapenems resistant isolates of P. aeruginosa are increasing worldwide. The aim of this study was to determine the carbapenem resistance mechanisms in clinical P. aeruginosa isolates from burn patients, in Tehran, Iran. A total of 53 non-duplicated isolates of carbapenem-resistant P. aeruginosa were collected from burn patients. The presence of carbapenemase genes were determined by PCR. AmpC overproducer isolates were detected by phenotypic method. The mutation and transcription level of oprD were determined by PCR-sequencing and quantitative Real-time PCR (RT-PCR), respectively. Twenty-seven (50.9%) isolates were positive for carbapenemase (bla VIM =25 and bla IMP =2) and showed high-level resistance to imipenem and meropenem. Twenty-eight isolates were AmpC overproducers. All isolates had a mutation in the oprD gene and down-regulation of oprD was found in 56.6% of MDR-PA isolates. Although the presence of carbapenemase is the common mechanism of resistant to carbapenem, but carbapenem resistance was found by oprD mutation-driven and the AmpC overproducing isolates in Tehran, Iran., (Copyright © 2017 Ministry of Health, Saudi Arabia. Published by Elsevier Ltd. All rights reserved.)

Introduction: The aim of this study was to determine whether an herbal extract containing monoterpene exhibited activity against multidrug-resistant Staphylococcus aureus and Pseudomonas aeruginosa isolated from clinical infection samples., Methods: The essential oil of Trachyspermum ammi (L.) Sprague ex Turrill (Apiaceae) fruit was extracted by hydrodistillation. Fruit residues were treated with hydrochloric acid and re-hydrodistilled to obtain volatile compounds. Compounds in the distilled oil were identified using gas-chromatography (GC) and GC-mass spectrometry (MS). The antibiotic susceptibility of all bacterial isolates was analyzed using both the disc diffusion method and determination of the minimum inhibitory concentration (MIC). The sensitivity of antibiotic-resistant isolates to essential oil was also determined by using the disc diffusion method and MIC determination., Results: Of 26 clinical isolates, 92% were multidrug-resistant (MDR). Aromatic monoterpenes (thymol, paracymene, and gamma-terpinene) were the major (90%) components of the oil. Growth of S. aureus strains was successfully inhibited by the oil, with an inhibitory zone diameter (IZD) between 30-60mm and MIC <0.02μL/mL. The oil had no antimicrobial activity against clinical isolates of P. aeruginosa; rather, it prevented pigment production in these isolates., Conclusions: This study revealed that the essential oil of Trachyspermum ammi, which contains monoterpene, has good antibacterial potency. Monoterpenes could thus be incorporated into antimicrobial ointment formulas in order to treat highly drug-resistant S. aureus infections. Our findings also underscore the utility of research on natural products in order to combat bacterial multidrug resistance.

Production of metallo-beta-lactamase (MBL) is one of the main mechanisms for resistance in carbapenem antibiotics. Detection of MBL-producer Pseudomonas aeruginosa is crucial in preventing its spread to other gram-negative bacteria. The aim of this study was to evaluate combination disc (CD) for identification of MBL-producer P. aeruginosa by polymerase chain reaction (PCR). A total of 255 imipenem resistant P. aeruginosa were collected from burn patients. Antibiotic susceptibility testing was conducted after purification and identification. Double-disc synergy test (DDST) with EDTA and combination disc test (CDT) with dipicolinic acid were performed for phenotypic detection of MBL and the PCR was carried out for blaVIM, blaIMP, blaNDM-1, blaSPM-1 genes. DDST with EDTA was negative in all cases, but 161 isolates were positive in CDT with dipicolinic acid. Further, blaVIM and blaIMP were detected in five and four strains, respectively. None of the isolates were positive for BlaNDM-1 and blaSPM-1 . The results of this study showed that the prevalence of MBL is low in imipenem resistance P. aeruginosa and that other mechanisms could be involved in resistance to imipenem in this bacterium., (© The Author(s) 2015.)

Background: Pseudomonas aeruginosa is known as an opportunistic pathogen responsible for nosocomial infections. Multidrug (MDR) resistance bacteria are considered as a worldwide issue. The current research goal to investigate the antibiotic susceptibility pattern in Extended Spectrum beta-lactamase and non Extended Spectrum beta-lactamase producing P. aeruginosa clinical isolates., Methods: A total of 76 P.aeruginosa clinical isolates were collected from Milad hospital in Tehran, Iran, during 8 months period in 2012. P.aeruginosa clinical isolates were subjected for ESBL production by phenotypic methods. The antibiotic susceptibility patterns were identified in ESBL and non-ESBL P. aeruginosa by MIC., Results: our results demonstrated that 76.3% (n =58) isolates were resistant to more than three antibiotics and classified as MDR. The majority of MDR strains were found in ESBL producer P. aeruginosa. ceftazidim as 3rd generation of cephalosporins, ciprofloxacin, Ticarcillin and aztreonam were found as a base for definition of MDR in the current research. The effectiveness antibiotics against ESBL and non-ESBL were meropenem and amikacin, respectively., Conclusion: based on our knowledge obtained from results, both ESBL and non-ESBL P. aeruginosa were resistant to extended antibiotics and this is a major health care problem. On the other hand, MDR strains more identified in ESBL producer P .a eruginosa. Also, carabapenem resistance observed in non-ESBL producer strains. Hence, it is recommended that the MDR strains should be following up. the prescription of ceftazidim, ciprofloxacin, Ticarcillin and aztreonam should be limited.

Background: Pseudomonas aeruginosa is an important cause of morbidity and mortality in patients with burns., Method: A total of 214 nonduplicated burn wound isolates of P. aeruginosa were recovered from burn patients. Identification of carbapenem resistant isolates and their antimicrobial susceptibility pattern was carried out using the phenotypic methods. The presence of genes encoding extended spectrum beta-lactamases (ESBLs) and metallo-beta-lactamases (MBLs) enzymes were determined by PCR. The genetic relationships between carbapenem resistant isolates were determined by Random Amplified Polymorphic DNA (RAPD)-PCR., Results: Of 214 investigated P. aeruginosa isolates, 100 (46.7%) were carbapenem resistant. All carbapenem resistant P. aeruginosa were resistant to imipenem, meropenem, ertapenem, carbenicillin, aztreonam, gentamicin and ciprofloxacin but susceptible to polymyxin B. Among 100 carbapenem resistant P. aeruginosa isolates, 3%, 65% and 52% were identified as ESBLs, carbapenemase and AmpC overproduction positive isolates respectively. The most prevalent ESBLs and MBLs genes included blaOXA-10 (97%), blaTEM (61%), blaVIM (55%), blaPER (13%), blaIMP (3%) and blaAIM (1%). RAPD analysis yielded 13 distinct profiles among 92 isolates. A dominant RAPD type was designated as A that consisting of 80 isolates., Conclusion: This is the first report of Adelaide IMipenmase (AIM) MBLs producing P. aeruginosa from Iran and also of the high prevalence of AmpC overproduction isolates. According to the results of current study, P. aeruginosa isolates producing OXA-10, TEM, VIM, PER and IMP beta-lactamases are frequent and the population structures of these isolates are highly similar., (Copyright © 2014 Elsevier Ltd and ISBI. All rights reserved.)

Pseudomonas aeruginosa is one of the common pathogenic causes of serious infections in burn patients throughout the world. Type III secretion toxins are thought to promote the dissemination of P. aeruginosa from the site of infection, the bacterial evasion of the host immune response and inhibition of DNA synthesis leading to host cell death. A total of 96 isolates of P. aeruginosa were collected from wound infections of burn patients, from April to July 2010. Antimicrobial susceptibility of the isolates were determined by disk agar diffusion method. Polymerase chain reaction (PCR)-based method was used for targeting the genes encoding the type III secretion toxins. The quantitative determination of biofilm-forming capacity was determined by a colorimetric microtiter plate assay. All the isolates were resistant to cefixime and ceftriaxone. More than 90% of the isolates were resistant to amikacin, carbenicillin, cefepime, cefotaxime, cefpodoxime, gatifloxacin, gentamicin, piperacillin/tazobactam, ticarcillin and tobramycin. All the isolates carried the exoT gene, 95% carried exoY, 64.5% carried exoU and 29% carried the exoS gene. Most of the isolates (58%) carried both exoY and exoU genes while 24% showed the concomitant presence of exoS and exoY and 1% carried both exoS and exoU. Coexistence of exoS, exoY and exoU was seen in 4% of the isolates. Biofilm formation was seen in more than 96% of the isolates among which 47% were strong biofilm producers, 26% were moderate and 22.9% were weak biofilm formers. In conclusion, the findings of this study show that the genes, particularly the exoU gene, encoding the type III secretion toxins, are commonly disseminated among the P. aeruginosa strains isolated from burn patients., (Copyright © 2012 Elsevier Ltd and ISBI. All rights reserved.)

Extended spectrum β-lactamase (ESBL)-producing trait was present in 48 out of the 112 (42.8%) Pseudomonas aeruginosa isolates collected from burn wound infections during a 12-month period. The presence of oxa-10, per-1, veb-1 and ges genes and the multiple-locus variable number of tandem repeats (VNTR) fingerprinting (MLVF) of 112 P. aeruginosa strains were determined by PCR and multiplex PCR. Disk diffusion methods were used to determine the susceptibility of the isolates to antimicrobial agents as instructed by CLSI. All ESBL isolates were resistant to aztreonam, cefepime, cefotaxime, cefpodoxime, ceftazidime, ceftriaxone and ofloxacin. Fewer than 60% of ESBL isolates were resistant to imipenem, meropenem, and piperacillin-tazobactam but more than 90% were resistant to amikacin, ciprofloxacin, levofloxacin, ticarcillin and tobramycin. The most prevalent ESBL genes included oxa-10 (70%) and per-1 (50%) followed by veb-1 (31.3%). The gene encodes GES enzyme did not detect in any isolates. A total of 100 P. aeruginosa strains were typed by MLVF typing method. MLVF produced 42 different DNA banding patterns. These data indicate that different MLVF types infect burn wounds in patients at a hospital in Tehran and also suggest an alarming rate of ESBL-producing isolates in this test location., (Copyright © 2011 Elsevier Ltd and ISBI. All rights reserved.)

Introduction: Several acute and chronic infections in humans can be caused by Pseudomonas aeruginosa (P.aeruginosa). Biofilm formation by these bacteria threatens health setting via increasing resistance against antimicrobial agents. Aim: To investigate the association between lasB and nanI genes with biofilm formation in P. aeruginosa clinical isolates. Materials and Methods: A total of 161 P. aeruginosa clinical isolates were collected. The Microtiter Plate (MTP) method was applied for biofilm formation assay. Gene amplification was conducted by PCR method with specific primers. Results: Present study findings showed that the prevalence of lasB and the nanI were 80.7% (130/161) and 24.8% (40/161), respectively. The biofilm formation results demonstrated that 15.5% (25/161) of isolates were not able to produce biofilm. It was considerable that the prevalence of lasB in P. aeruginosa producing biofilm was higher. Conclusion: lasB can be considered as an effective factor for biofilm formation in P. aeruginosa isolates. [ABSTRACT FROM AUTHOR]

Background and Objectives: Pseudomonas aeruginosa is a Gram-negative, aerobic bacterium found in water and soil. It is a normal flora in skin and gastrointestinal tract of human beings. P. aeruginosa as an opportunistic pathogen involved in nosocomial infections having multiple pathogenic factors and shows high rate of resistance to different antibiotics. The aim of this study was to identify the most important native medicinal plants of Iran effective on P. aeruginosa. Materials and Methods: All required information was obtained by searching keywords such as P. aeruginosa, medicinal plant extracts or essential oils in published articles in authentic scientific databases such as Science Direct, Wiley-Blackwell, Springer, Google scholar, Scientific Information Database (SID) and Magiran. Results: According to the literature review, our results showed 12 different native medicinal plants were effective against P. aeruginosa in Iran including Eucalyptus camadulensis, Marticaria chamomilla, Ferula gummosa Boiss, Lawsonia inermis, Ocimumgra tissimum, Allium sativum, Satureja hortensis L, Satureja bachtiarica Bunge, Satureja khuzestanica (Jamzad), Thymus daenensis Celak, Thymus carmanicus Jalals and Camellia sinensis. Conclusion: Phytochemical analysis has shown that bioactive compounds of medicinal plants with their antioxidant and antimicrobial properties can be good alternatives for the synthetic medicines in food and drug industry. [ABSTRACT FROM AUTHOR]

Background and Objectives: The oprD mutation and AmpC overproduction are the main mechanisms of intrinsic resistance to carbapenems such as imipenem and meropenem in Pseudomonas aeruginosa. Materials and Methods: In this study, we investigated intrinsic resistance to carbapenems including mutation of oprD and AmpC overproduction in a carbapenem-resistant P. aeruginosa isolated from a burn patient by phenotypic and molecular methods. Results: In our study, the carbapenem-resistant P. aeruginosa isolate was resistant to imipenem, meropenem, cefepime, gentamicin, ceftriaxone, carbenicillin, aztreonam and ciprofloxacin but was susceptible to ceftazidime and polymyxin B. The minimum inhibitory concentrations (MICs) against imipenem, meropenem and ceftazidime were 64 µg/ml, 16 µg/ml and 2µg/ml, respectively. The isolate was ESBLs and AmpC overproducer. No carbapenemase activity was detected by Modified Hodge test (MHT). This isolate was carrying only blaOXA-10. PCR amplification and sequencing of oprD performed on isolate resulted in PCR product of 2647bp. Sequence analysis of the 2647bp product revealed insertion of a sequence of 1232 bp at position 8 in coding region of oprD. Conclusion: According to the results of this study, oprD mutation and AmpC overproduction can cause the main mechanism of resistance of P. aeruginosa to carbapenems. [ABSTRACT FROM AUTHOR]

Background and Objectives: Pseudomonas aeruginosa is responsible for devastating nosocomial infections among severely burn patients. Class C of cephalosporinase (AmpC-β-lactamases) is important cause of multiple β-lactam resistance in P. aeruginosa. The aim of this study was to detect the AmpC-β-lactamases producing isolates among carbapenem resistant P. aeruginosa isolated from burn patient. Material and Methods: a total of 100 isolates of carbapenem resistant P. aeruginosa isolates from different burn patients were investigated. Three phenotypic methods were selected for identiication of the AmpC-β-lactamases producing isolates. Results: Fifty four isolates were AmpC producer as detected by AmpC disk test. Seventeen isolates were identiied as AmpC producer using combined disk method. Fifty two isolates showed a twofold or threefold dilution difference between the minimum inhibitory concentration of imipenem or ceftazidime and the minimum inhibitory concentration of imipenem or ceftazidime plus cloxacillin. One isolate was identiied as AmpC producer using three methods. Three isolates produced AmpC as detected by both AmpC disk test and combined disk methods and 19 isolates were found as AmpC producer using both AmpC disk test and minimum inhibitory concentration methods. Six isolates were AmpC producer as shown by the MICs of both imipenem and ceftazidime. Conclusion: According to the results of this study, AmpC- β-lactamase looks to be the main mechanism of resistance of Pseudomonas aeruginosa to cephalosporins and carbapenems in the study hospital. [ABSTRACT FROM AUTHOR]

Introduction: Pseudomonas aeruginosa is a Gram-negative bacterium that considered as important opportunistic human pathogen. One of the mechanisms that help bacteria to tolerate survival in adverse conditions and resistance to antibiotics is biofilm formation through quorum sensing (QS) signals and toxin-antitoxin (TA) systems. QS and TA are two systems that have important roles in biofilm formation. QS is a global regulatory mechanism that enable bacteria to communicate with each other by production of auto inducers (AI) molecules in population. Because of importance biofilm formation in P. aeruginosa infections, here, we studied frequency of QS and TA genes among clinical isolates of P. aeruginosa with ability of biofilm formation. Materials and Methods: One hundred and forty clinical isolates of P. aeruginosa were collected from Tehran and Ilam hospitals. The isolates were identiied by biochemical tests. Biofilm formation was evaluated by microplate method. After DNA extraction by boiling method, the frequency of QS genes (lasIR, rhllR), and TA genes (mazEF, relBE, hipBA, ccdAB and mqsR) were analyzed by PCR. Results: Our results showed that maximum resistance is related to aztreonam (72.85%) antibiotic. Most of isolates were able to produce biofilm (87.15%) and the majority of them formed strong biofilm (56.42%). PCR results showed that frequency of mazEF, relBE, hipBA, ccdAB, mqsR, lasIR and rhlIR genes were 85.71, 100, 1.42, 100, 57.14, 93.57 and 83.57 percent, respectively. Conclusion: Clinical isolates of P. aeruginosa had high ability to form biofilm, and QS and TA system genes among these isolates were very high (except hipBA genes). There are significant correlation between biofilm for mation and present of QS and TA system genes. [ABSTRACT FROM AUTHOR]