جستجوی مقالات مرتبط با کلیدواژه « drug resistance p » در نشریات گروه « پزشکی »

Enterococcus is a part of normal gastrointestinal flora in human body. Nevertheless, antibiotic-resistant Enterococcus (ARE) is considered a key factor in nosocomial infections which result in a considerable increase in the rate of patient death due to referring of numerous patients to health centers annually, or lead to extended disease convalescence.

This study aimed to evaluate the bactericidal effect at 405nm diode at a laser power of 30 mW on ARE viability of clinical infections.

In the present study, 30 isolates underwent antibiotic susceptibility test (AST) in which sensitivity to piperacillin (100 µg), rifampin (5 µg), and oxacillin (1 µg) were measured based on the Clinical and Laboratory Standards Institute (CLSI) guidelines. Afterwards, ten most resistant isolates were selected and irradiated by a 405 nm diode laser at a power of 30 mW for 180 and 240 seconds. The data were reported statistically as mean ± standard deviation, and the analysis of the data on varied bacteria was performed using ANOVA. The result was evaluated by SPSS software and P value ≤0.05 was interpreted to be significant.

Bacterial viability decreased unsteadily to 10 resistant isolates. Moreover, enhancing irradiation time caused a lower viability rate in such a way that the viability of isolate 9 having the lowest viability rate was reduced from 2.94% in 180 seconds to 0.58% in 240 seconds. The result was evaluated by SPSS software and P value was determined to be significant, and P≤0.05 was laser irradiation for either 180 s or 240 s.

Following the study results, 405 nm diode laser could be applied as a tool for eliminating clinical ARE, and it was useful for preventing hospital-acquired infections.

A series of aminoguanidine derivatives containing an acylhydrazone moiety was designed based on combination principles to find new antibacterial agents with wide spectra and high activities. The synthesized compounds were characterized by spectral methods and screened for their antibacterial activity. The results showed that several compounds provided great antimicrobial activities against Gram-positive bacteria (including the multidrug-resistant clinical isolates). Especially, this series of compounds presented high potency against Staphylococcus aureus, among which the derivative 3f was the most promising one with a MIC value of 4 μg/mL. Compound 3d, with a tertiary butyl group, was found to have the broad spectrum inhibitory capacity, which is effective to eight strains and showed the most potent inhibitory activity against B. subtilis CMCC 63501 with a MIC value of 4 μg/mL. What’s more, compound 3d also presented high activities against four multidrug-resistant strains, which were comparable or potent to oxacillin and penicillin. Molecular docking studies revealed that H-bond interaction with amino acid residue THR81 and alkyl hydrophobic interaction with residue ALA246 of FabH were crucial for their binding force and in-vitro antimicrobial activities.

Doxorubicin (Dox) is one of the most well-known chemotherapeutics that are commonly applied for a wide range of cancer treatments. However, in most cases, efflux pumps like P-glycoprotein (P-gp), expel the taken drugs out of the cell and decrease the Dox bioavailability. Expression of P-gp is associated with elevated mRNA expression of the ATP-binding cassette B1 (ABCB1) gene.

In the current study, different sequences of cell-penetrating peptides (CPPs) containing tryptophan, lysine, and arginine and their nano-complexes were synthesized and their impact on the expression and activity of the ABCB1 gene was evaluated in the A549 lung carcinoma cell line. Furthermore, the cellular uptake of designed CPPs in the A549 cell line was assessed.

The designed peptides, including [W4K4], [WR]3-QGR, R10, and K10 increased Dox cytotoxicity after 48 hr. Furthermore, arginine-rich peptides showed higher cellular uptake. Rhodamin123 accumulation studies illustrated that all the obtained peptides could successfully inhibit the P-gp pump. The designed peptides inhibited the ABCB1 gene expression, of which, [W4K4] resulted in the lowest expression ratio.

[W4K4], [WR]3-QGR, R10, and K10 could successfully increase the Dox cytotoxicity by decreasing the efflux pump gene expression.

Antibiotic resistance transmission through the food chain is considered as a major health challenge. The combination of essential oils (EOs) with synergistic or additive effects regarding enhancing the antimicrobial activity is an applied approach for controlling foodborne pathogens and improving food safety. The aim of this study was to evaluate the combined effect of Cinnamomum camphora (cinnamon) and Syzygium aromaticum (clove) EOs against TEMbla produced by Escherichia coli isolated from poultry colibacillosis.

To this end, 100 E. coli isolated from the viscera of broilers suspected of colibacillosis, were examined to detect the ESBL produced by the combined disk method according to The Clinical and Laboratory Standards Institute (CLSI). In addition, TEMbla presence was detected by the polymerase chain reaction method. Finally, the antibacterial activity of cinnamon and clove EOs was studied against TEMbla harboring isolates alone and in combination with the broth microdilution method and fractional inhibitory concentration (FIC) index.

Based on the results, 32/88 (36.3%) of the tested samples produced ESBL and 20/32 (62.5%) were found to harbor TEM. All the TEMbla produced by E. coli investigated by the broth microdilution assay were sensitive to cinnamon and clove EOs in the range of 400 to 1600 and 800 to 3200 ppm, respectively. FIC indices (ranging from 0.56 to 1) suggested their synergistic inhibitory effect on nine isolates and additive inhibitory effect against 11 isolates.

The results of this study indicated that the combination of cinnamon and clove can inhibit the growth of E. coli harboring the TEMbla gene and thus it can be suggested as a safe bio-preservative. However, further studies should be conducted to investigate the potential interaction between the EOs and food matrix components.

Pseudomonas aeruginosa is an important non-fermenting gram-negative hospital-acquired pathogen. Treatment of P. aeruginosa infections has become more challenging due to overexpression of efflux pumps. The aim of the present study was to apply in silico analysis to evaluate the structure of the efflux pump regulatory protein, MexR, and impact of mutation on its stability and function.

Different bioinformatics tools including EXPASY, PROTEER, TECCOFFE, iStable, I-Mutant 2, STRING, ESPript, GOR IV, and PDB were used in the study.

Aliphatic and instability indices were 104.15, and 46.52, respectively, indicating that the protein has a relatively short half-life. Most mutations decreased protein stability. Twenty-four mutations were identified as deleterious, with negative impact on the protein’s function.

Determination of structure, variability, and function of MexR could be useful for modeling of treatment and control of multidrug resistant P. aeruginosa, with overexpressed efflux pump. We found that MexR is a relatively unstable and conserved protein and the majority of mutations decrease its stability.

Staphylococcus aureus is one of the main agents of nosocomial infections. Identifying coagulase enzyme in staphylococcal infections is of great importance as it is one of the main virulence agents. The present study aims to accurately detect the presence of coagulase gene and its relationship with antibiotic resistance patterns in clinical isolates.
In this experimental study, a total of 20 clinical samples of S. aureus and 10 clinical samples of coagulase-negative staphylococci were collected and identified from hospitals and laboratories in Nowshahr and Chalous. Antibiotic resistance patterns of isolates were examined based on CLSI and finally polymerase chain reaction was used in order to detect the presence of coagulase gene with specific primers. Treatments were examined in three intervals and the results were analyzed using one-way analysis of variance (ANOVA), univariate ANOVA, and t-test at the probability level of P Suggested that isolates showed phenotypic presence of coagulase enzyme and had this gene genotypically as well. Coagulase-positive samples demonstrated higher resistance to tetracycline 20%, oxacillin 55%, gentamicin 20%, and kanamycin 25%. Statistically, there was no significant difference among inhibition zone diameters of oxacillin, nalidixic acid, gentamicin, kanamycin, and penicillin.
Coagulase gene causes antibiotic resistance and coagulase-negative staphylococci are spreading rapidly and their resistance is increasing.

Neuraminidase (NA) is one of the surface proteins of influenza A virus, which plays an important role in immunization against influenza infection and is recognized as an important therapeutic target. Genetic and antigenic changes and substitutions can influence the efficacy of vaccine and change viral sensitivity to NA inhibitors (NAIs). In this study, we performed phylogenetic and molecular analyses of NA changes in influenza A(H1N1)pdm09 virus, compared them with the corresponding vaccine strain, and examined drug resistance mutations in isolates from patients.
The complete sequence of NA genes from 34 pandemic H1N1 isolates (identified in 2009-2010, 2010-2011, and 2013) was determined and analyzed both genetically and antigenically. The phylogenetic tree was plotted relative to the corresponding vaccine strain, using MEGA6 software package, based on the maximum likelihood method and JTT matrix (bootstrap value of 1000).
The phylogenetic analysis of pandemic isolates showed 31 amino acid substitutions in NA genes, compared to the vaccine strain . Some of these substitutions (N248D, V241I, N369K, N44S, and N200S) were important in terms of phylogenetic relationship, while the rest (D103N, V106I, R130T, N200S, G201E, and G414R) influenced the antigenic indices of B-cell epitopes. The catalytic sites, framework sites, and N-glycosylation remained unchanged in the studied samples. Meanwhile, H275Y substitution, related to oseltamivir resistance, was detected in 3 isolates. The average nucleotide identity of NAs with the corresponding vaccine strain was 99.415%, 98.607%, and 98.075% in 2009-2010, 2010-2011, and 2012-2013, respectively.
In this study, we provided basic information on the genetic and antigenic changes of NA genes in influenza A(H1N1)pdm09 virus from patients in 3 different seasons in Tehran, Iran. Considering the viral NAI resistance and changes in NA gene sequences of the isolates in comparison with the vaccine strain, further studies should be performed to monitor genetic changes in Iran. Moreover, the efficacy of vaccines should be examined.

Cytomegalovirus (CMV) is one of the most frequently encountered opportunistic viral pathogens in renal transplantation. Approximately, in 60% of the transplant recipients CMV infection can be observed and in > 20% symptomatic diseases can be developed. However, antiviral prophylaxis and treatment have reduced the CMV morbidity and mortality at the time of development of antiviral-resistance CMV strains that can significantly contributed to the adverse clinical outcomes in transplant recipients. Mutations in the human CMV UL97 kinase gene are a major mechanism of viral resistance to the anti-CMV drug “Ganciclovir (GCV)”. GCV, as the most widely used and recognized therapy for CMV, is a substrate for the UL97 kinase.
The studied patients were renal transplant recipients in Tehran Labbafinejad hospital who were positive for CMV-DNA PCR test and have been treated with Ganciclovire. Patients who have been treated for at least 3 weeks with GCV and have not shown a proper therapeutic response were candidate for UL97 gene mutations associated with GCV resistance evaluation.
About 60 patients with positive CMV DNA PCR were hospitalized during one year study. Eventually, after 2 times measurement of CMV viral load at the end of the third week and third month of therapy with Ganciclovire, 5 cases were candidate for antiviral resistance evaluation. Genotypic testing was performed, but no mutation neither in UL97 nor in UL 54 was detected by the laboratory.
The increasing use of antiviral drugs in transplant patients associated with the narrow range of antiviral agents effective to treat CMV have increased our need for further understanding of the risk factor for development of CMV antiviral resistance and it’s clinical impacts. Detection of UL97 gene mutation plays a major role to determine therapeutic strategies to treat patients infected with the resistant viruses.

Enterococcus spp., belonging to the group of lactic acid bacteria, are Gram-positive ubiquitous commensals of the intestines of human beings as well as warm-blooded animals. The main objective of this study was to determine the occurrence and antimicrobial resistance of Enterococcus spp. isolated from lettuce and irrigation water in Abidjan, Côte dIvoire.
A total of 72 samples, including leaves of lettuce (n=36) and irrigation water (n=36) were randomly collected from three different agricultural sites located in Abidjan city, Côte dIvoire. After microbial analysis and identification of Enterococcus spp. by culturing and biochemical methods, antimicrobial susceptibility tests were carried out using disk diffusion method. Data were analyzed by statistical processing software R (R 3.0 for Windows).
E. faecalis was recognized as the most prevalent strain which was found in 27 out of 36 (75%) lettuce as well as 29 out of 36 (80.5%) irrigation water samples. The mean Enterococcus load of lettuces and irrigation water samples were 2.3±0.7 and 3.6±2 log Colony Forming Unit per g lettuce, respectively. Among 45 studied enterococci isolates, the most antibiotic-resistance rates were related to erythromycin (54%) and also co-trimoxazole (49%).
There is a considerable public health concern regarding raw consumption of lettuce cultivated in Abidjan city which can cause gastroenteritis diseases in consumers.

pfmdr1 and its variants are molecular marker which are responsible for antibiotics resistance in Plasmodium falciparum, a parasitic carrier for malaria dis­ease. A novel strategy to treat malaria disease is by disrupting parasite lactate dehydro­genase (pLDH), a crucial enzyme for Plasmodium survival during their erythro­cytic stages. This research was aimed to investigate and characterize the pfmdr1 and pldh genes of P. falciparum isolated from Nusa Tenggara Indonesia. Genomic DNA of P.falciparum was isolated from malaria patients in Nusa Tenggara Indonesia. pfmdr1 was amplified using nested PCR and genotyped using Restriction Fragment Length Polymorphism (RFLP). pldh was amplified, se­quenced, and analyzed using NCBI public domain databases and alignment using Clustal W ver. 1.83. Genotyping of the pfmdr1 revealed that sequence diversity was extremely high among isolates. However, a sequence analysis of pldh indicated that open read­ing frame of 316 amino acids of the gene showing 100% homology to the P. falcipa­rum 3D7 reference pldh (GeneBank: XM_001349953.1). This is the first report which confirms the heterologous of pfmdr1 and the homologous sequences of P.falciparum pldh isolated from Nusa Tenggara Islands of Indonesia, indicating that the chloroquine could not be used effectively as antimalar­ial target in the region and the pLDH-targeted antimalarial compound would have higher chance to be successful than using chloroquine for curbing ma­laria worldwide.