Photodynamic Therapy and Its Synergism with Melittin Against Drug-Resistant Acinetobacter baumannii Isolates with High Biofilm Formation Ability.

Drug-resistant biofilm producer A. baumannii isolates are a global concern that warns researchers about the development of new treatments. This study was designed to analyze the effect of photodynamic therapy (PDT) as monotherapy and associated with melittin on multidrug-resistant A. baumannii isolates. Sub-lethal doses of photosensitizer, LED, and PDT were determined. The PDT effect on the biofilm and expression of biofilm-associated genes was evaluated by scanning electron microscopy and quantitative real-time PCR (qRT-PCR) methods, respectively. The synergistic effect of PDT and melittin on the survival of MDR/XDR strong biofilm producer isolates was evaluated by checkerboard assay. Survival rates were significantly decreased at the lowest concentration of 12.5-50 µg/ml in 4 min at an energy density of 93.75 J/cm2 (P < 0.05). The optimized PDT method had a bactericidal effect against all tested groups, and the mean expression levels of csu, abaI, bap, and ompA genes in the strong biofilm producers were decreased significantly compared to the control group. The combined effect of LED and melittin successfully reduced the MDR/XDR A. baumannii strong biofilm producers' growth from 3.1 logs. MB-mediated aPDT and combined treatment of PDT with melittin, which has been investigated for the first time in this study, can be an efficient strategy against MDR/XDR A. baumannii isolates with strong biofilm production capacity.

Fluoroquinolone-resistance mechanisms and molecular epidemiology of ciprofloxacin-resistant Klebsiella pneumoniae isolates in Iran.

Klebsiella pneumoniae is an important cause of nosocomial infections and displays increasing resistance to fluoroquinolones (FQ). This study surveyed the mechanisms of FQ resistance and molecular typing of K. pneumoniae isolates from intensive care units patients in Tehran, Iran. A total of 48 ciprofloxacin (CIP) resistant K. pneumoniae isolates from urine samples were included in this study. Broth microdilution assays revealed high-level CIP resistance (MIC > 32 µg/mL) in 31.25% of the isolates. Plasmid-mediated quinolone resistance genes were detected in 41 (85.4%) isolates. Among which, qnrS (41.67%) was the most prevalent followed by qnrD (35.42%), qnrB (27.1%), qnrA (25%), qepA (22.9%), aac(6')-Ib-cr (20.83%), and qnrC (6.25%). Target site mutations (gyrA and parC) were assessed using PCR and sequencing on all isolates. A single mutation in gyrA (S83I) was found in 13 (27.1%) isolates and two isolates harbored six simultaneous mutations. Fourteen isolates (29.2%) had mutations in parC and S129A and A141V mutations were the most prevalent. Real time PCR showed an increase in the expression level of acrB and oqxB efflux genes in 68.75 and 29.16% isolates, respectively. Enterobacterial repetitive intergenic consensus (ERIC)-PCR revealed 14 genotypes and 11 of them were classified by multilocus sequence typing (MLST) into 11 different sequence types belonging to seven clonal complexes and two singletons, most of them have not been reported in Iran yet. We are concerned about the spread of these clones throughout our country. Most FQ resistance mechanisms were detected among our isolates. However, target site mutation had the greatest effect on CIP resistance among our isolates.

The Human Host Defense Peptide LL-37 Overexpressed in Lung Cell Lines by Methanolic Extract of Valeriana officinalis

Abstract The present study investigated the effects of valerian methanolic extract and valerenic acid on the expression of LL-37 gene and protein in A549 and MRC5 line cells. After preparing Valerian seeds, sowing them in March 2020, and harvesting the rhizome in October 2020, the extract was prepared from the valerian rhizome by maceration method. Valerian acid content was determined using high performance liquid chromatography (HPLC). Two cell lines (A549 and MRC-5) were used to study the effects of valerian extract, and the MTT test was used to evaluate cell viability. The expression of LL-37 mRNA and protein was assessed by Real-Time PCR and western blot, respectively. In vivo safety assessments and histopathological analysis were also conducted. Data was analyzed by Graphpad Prism 8 software. Valerian methanolic extract and valerenic acid upregulated the LL-37 mRNA and protein expression in both treated cell lines. Valerenic acid showed a greater effect on upregulating LL-37 expression than valerian methanolic extract. A549 cells were more sensitive to valerian methanolic extract compared to MRC5 cells, and its cell viability was reduced. Furthermore, liver and kidney-related safety assessments showed that valerian methanolic extract had no toxic effects. In general, it was concluded that the methanolic extract of valerian as well as the resulting valerenic acid as the most important component of the extract has the ability to upregulate LL-37expression. Therefore, methanolic extract of valerian and valerenic acid can be considered for improving the immune system.

Fluoroquinolone resistance contributing mechanisms and genotypes of ciprofloxacin- unsusceptible Pseudomonas aeruginosa strains in Iran: emergence of isolates carrying qnr/aac(6)-Ib genes / Mecanismos que contribuyen a la resistencia a las fluoroquinolonas y genotipos de cepas de Pseudomonas aeruginosa no sensibles a la ciprofloxacina en Irán: emergencia de aislamientos portadores de genes qnr/aac(6)-Ib

Background: Fluoroquinolones (FQs) including ciprofloxacin (CIP) are key antibiotics for the treatment of Pseudomonas aeruginosa infections, but resistance to FQs is developing as a result of chromosomal mutations or efflux pump effects. Plasmid-mediated quinolone resistance (PMQR) has been recently reported in the Enterobacteriaceae family. This study aimed to investigate the mechanisms of CIP insusceptibility in P. aeruginosa isolates from ICU patients and to characterize their genotypes. Methods: A total of 40 ciprofloxacin unsusceptible (CIP-US) P. aeruginosa isolates from Tehran hospitals were recruited in this study. A broth microdilution assay was performed to find acquired resistance profiles of the isolates. All isolates were screened for target-site mutations (gyrA and parC), PMQR genes, and efflux pumps (mexB, D, Y, and E) expression. Clonality was determined by random amplified polymorphic DNA (RAPD)-PCR, and genotyping was performed on 5 selected isolates by analyzing 7 loci in the existing multilocus sequence typing scheme. Results: Thirty-eight out of 40 CIP-US isolates (95%) were categorized as MDR. Seven (17.5%) had gyrA mutation in codons 83, and no mutation was detected in parC; 77.5% of the isolates were positive for PMQR genes. Among PMQR genes, qnrB (30%), qnrC (35%), and qnrD (30%) predominated, while qnrA, qnrS, and aac(6)-Ib genes were harbored by 20.5%, 12.5%, and 15% of the isolates respectively. Efflux pump protein expression was observed in 35% of the isolates. After RAPD-PCR, 19 different genotypes were yielded, and 5 of them were classified into sequence types (STs): 773, 1160, 2011, 2386, and 359. Conclusion:In this first-time study on P. aeruginosa CIP-US strains from Iranian ICU patients, three main CIP unsusceptibility mechanisms were investigated. A single mutation in one CIP target enzyme could explain high CIP resistance. qnr genes in the isolates can be considered as a CIP-unsusceptibility mechanism among...(AU)

Streptococcus mutans and Streptococcus sobrinus contributions in dental caries in Iranian and Afghan children: A report from serotype distribution and novel STs.

OBJECTIVE: This study evaluated the frequency and the effects of S. mutans and S. sobrinus on Decayed, Missing, and Filled Teeth (DMFT) scores in Iranian and Afghan populations. Serotyping of S. mutans isolates and multi-locus sequence typing (MLST) were the secondary goals. DESIGN: This study was performed on 360 saliva and plaque samples from people from age groups of 4-7 and 15-17 years with Iranian and Afghan nationality who were residents of Tehran province. The DMFT index of the study population was determined, and S. mutans and S. sobrinus were identified using species-specific primers. Following the collagen-binding protein of S. mutans (cnm) gene identification, serotypes were determined, and genotyping was performed on eight selected isolates by assessing eight loci in the existing MLST scheme. RESULTS: Of 360 samples, 300 were recruited as population study. Of these, 204 (51%) harbored S. mutans alone. In 42 specimens (10.5%), both specious were detected, and 54 (13.5%) were free of both. The frequencies of c, f, e, and k serotypes were 47.5%, 17.9%, 13.8%, and 8.1%, respectively. The frequency of serotype f was significantly higher in four-year-old Iranian children. MLST showed eight different sequence types (STs), which were confirmed as novel singleton sequence types. CONCLUSIONS: The high frequency of serotypes k and f as systemic serotypes with the cnm gene among the Iranian population suggests the need for more worldwide studies on serotype distribution. Since very few studies have reported the epidemiological status of mutans streptococci (MS), the molecular properties of the isolates are unknown. Thus, the STs reported in this study should be considered as emerging strains.

Fluoroquinolone resistance contributing mechanisms and genotypes of ciprofloxacin- unsusceptible Pseudomonas aeruginosa strains in Iran: emergence of isolates carrying qnr/aac(6)-Ib genes.

BACKGROUND: Fluoroquinolones (FQs) including ciprofloxacin (CIP) are key antibiotics for the treatment of Pseudomonas aeruginosa infections, but resistance to FQs is developing as a result of chromosomal mutations or efflux pump effects. Plasmid-mediated quinolone resistance (PMQR) has been recently reported in the Enterobacteriaceae family. This study aimed to investigate the mechanisms of CIP insusceptibility in P. aeruginosa isolates from ICU patients and to characterize their genotypes. METHODS: A total of 40 ciprofloxacin unsusceptible (CIP-US) P. aeruginosa isolates from Tehran hospitals were recruited in this study. A broth microdilution assay was performed to find acquired resistance profiles of the isolates. All isolates were screened for target-site mutations (gyrA and parC), PMQR genes, and efflux pumps (mexB, D, Y, and E) expression. Clonality was determined by random amplified polymorphic DNA (RAPD)-PCR, and genotyping was performed on 5 selected isolates by analyzing 7 loci in the existing multilocus sequence typing scheme. RESULTS: Thirty-eight out of 40 CIP-US isolates (95%) were categorized as MDR. Seven (17.5%) had gyrA mutation in codons 83, and no mutation was detected in parC; 77.5% of the isolates were positive for PMQR genes. Among PMQR genes, qnrB (30%), qnrC (35%), and qnrD (30%) predominated, while qnrA, qnrS, and aac(6)-Ib genes were harbored by 20.5%, 12.5%, and 15% of the isolates respectively. Efflux pump protein expression was observed in 35% of the isolates. After RAPD-PCR, 19 different genotypes were yielded, and 5 of them were classified into sequence types (STs): 773, 1160, 2011, 2386, and 359. CONCLUSION: In this first-time study on P. aeruginosa CIP-US strains from Iranian ICU patients, three main CIP unsusceptibility mechanisms were investigated. A single mutation in one CIP target enzyme could explain high CIP resistance. qnr genes in the isolates can be considered as a CIP-unsusceptibility mechanism among studied isolates. Efflux pumps have more contribution in multidrug resistance than CIP susceptibility. CIP-US isolates of this study have not spread from distinct clonal strains and probably emerged from different sources. STs identified for the first time in this study in Iran should be considered as emerging MDR strains.

In silico targeting SARS-CoV-2 spike protein and main protease by biochemical compounds.

Since there is no general agreement on drug treatment of SARS-CoV-2, the search for a new drug capable of treating COVID-19 is of utmost priority. This study aims to dereplicate the chemical compounds of the methanol extract of Salvia officinalis and Artemisia dracunculus, and assay the inhibitory effect of these compounds as well as the previously dereplicated components of Zingiber officinale against SARS-CoV-2 in an in-silico study. A molecular networking (MN) technique was applied to find the chemical constituents of the extracts. Docking analysis was also used to find the binding affinity of dereplicated components from S. officinalis, A. dracunculus, and Z. officinale to COV-2-SP and Mpro. 57 compounds were dereplicated from the MeOH extracts of S. officinalis and A. dracunculus which include the class of polyphenols, flavonoids, coumarins, phenylpropanoids, anthocyanins, and dihydrochalcones. Molecular docking analysis indicated a high affinity of about 27 compounds from three mentioned plants against studied targets. kaempferol 3-O-rutinoside, neodiosmin, and querciturone with docking score values of -10.575, -10.208, and - 9.904 Kcal/mol and ki values of 0.016606, 0.030921, and 0.051749, respectively were found to have the highest affinities against COV-2-SP. 2-phenylethyl beta-primeveroside, curcumin PE, and kaempferol 3-O-rutinoside also indicated the highest affinity against Mpro with docking scores of -10.34, -10.126 and - 9.705 and ki values of 0.024726, 0.035529, and 0.072494, respectively. MN can be successfully used for the dereplication of metabolites from plant extracts. In addition, the in-silico binding energies introduced several inhibitors from Z. officinale, S. officinalis, and A. dracunculus for the treatment of SARS-CoV-2 disease. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s11756-021-00881-z.

Antibacterial, anti-biofilm and anti-quorum sensing activities of Artemisia dracunculus essential oil (EO): a study against Salmonella enterica serovar Typhimurium and Staphylococcus aureus.

The study evaluates the effect of Artemisia dracunculus essential oil (EO) on two pathogenic bacteria Salmonella enterica serovar Typhimurium and Staphylococcus aureus and Vero cell line. To evaluating the anti-biofilm potential of the EO, a microtiter-plate test (MtP) and scanning electron microscopy (SEM) were performed. The quorum-sensing inhibitory properties were examined by QS-related gene expression at sub-MIC concentrations of Artemisia dracunculus EO. MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, a tetrazole) test was used to determine the cytotoxicity potential of the EO against the Vero cell line and finally, the major components of the EOs were determined using Gas chromatography-mass spectrometry (GC-MS) analysis. The minimum inhibitory concentration (MIC) of the tested EO against S. Typhimurium and S. aureus were 2.5 and 1.25 µl/ml, respectively. In addition, the minimum bactericidal concentration was 5 and 2.5 µl/ml for S. Typhimurium and S. aureus, respectively. Both MtP and SEM showed an acceptable inhibitory and disruption effect of the EO on the biofilm formation at Sub-MIC concentrations. Significant downregulation of luxS, pfs, and hld genes by treatment with MIC/2 concentration of A. dracunculus EO was observed. The IC50 value of A. dracunculus EO against Vero cells was 20 µl/ml. The main detected compound using GC-MS was estragole (methyl chavicol or tarragon) (64.94%). Anti-biofilm, QSI activity, and non-toxicity of A. dracunculus EO reported for the first time in this study propose the use of these plant compounds as alternatives to antibiotics and chemical additives.

Streptococcus mutans and Streptococcus sobrinus distribution in the saliva and plaque of Iranian population: Higher prevalence of S. mutans serotypes f and k.

OBJECTIVE: This study aimed to find the relation of the MS co-existence with the decayed, missing (Extracted) and filled teeth (DMFT) score and the prevalence of Streptococcus mutans serotypes in the Iranian population. METHODS: In this cross-sectional research conducted in 2018, volunteers aged 10-60< years were measured by population selection criteria. PCR technique was used to screen MS serotypes in the homogenized saliva and plaque samples. RESULTS: 499 subjects met the selection criteria of the study population. Out of 499 samples, 448 samples were finalized for serotype determination and DMFT relation evaluation. From 448, 348 (77.6%) samples harboured only S. mutans, 44 (9.8%) had both S. mutans and S. sobrinus, 6 (1.3%) were positive for S. sobrinus alone, and 94 (20.9%) were free of both specious. The mean DMFT score in people with S. mutans (6.7) was higher than S. mutans negative (4.6) participants (p < 0.05). In people with both S. mutans and S. sobrinus, the mean DMFT did not change significantly. The frequency of c, e, f and k serotypes was 47.7, 22.7, 27.5 and 22.1%, respectively. The mean DMFT score in participants with serotype e was significantly higher than others (p < .05). CONCLUSIONS: People can acquire different S. mutans serotypes over a lifetime. The high prevalence rate of serotype k, a systemic S. mutans serotype, calls worldwide studies on the prevalence of serotype k strains.

Antimicrobial activity of ginger on cariogenic bacteria: molecular networking and molecular docking analyses.

Streptococcus mutans and Streptococcus sobrinus have been implicated as the primary causative agents of dental caries in humans. This study aimed to screen the antibacterial activity of the n-hexane, ethyl acetate, methanol, and aqueous extracts of Ginger against mentioned bacteria and investigate chemical constituents of the extracts, and their activity against some drug targets in S. mutans. Antimicrobial tests including biofilm inhibition, time-kill kinetics, and adherence inhibition alongside cytotoxicity of extracts, were assessed. A molecular networking technique was used to find chemical constituents of the extracts. Molecular docking analysis on the Schrodinger package was applied to identify the binding interactions of the compounds to targeted enzymes. Methanol and ethyl acetate extracts showed the highest antibacterial activity against S. mutans and S. sobrinus. Different compounds including polyphenols, alkaloids, anthraquinones, flavonoids, terpenoids, glycosides, steroids, and reducing sugars dereplicated from Ginger extracts. The binding affinity of ligands with free hydroxyl groups was better than other ligands against all tested enzymes. This study introduces a wide range of Z. officinal extracts compounds to be used in different drug discovery studies. Some Ginger compounds with high affinity to investigated enzymes can be considered as candidate compounds for anti-caries drug development studies.Communicated by Ramaswamy H. Sarma.

Hepatitis C virus in Iran; transmission routes, growth in 3a genotype distribution, and lack of liver marker relation with genotypes.

BACKGROUND: The hepatitis C virus (HCV) outbreak in Iran is increasing. This study investigated the dissemination and transmission routes of HCV genotypes in different regions of Iran. The relationship between serum biochemical markers and viral genotypes was also assessed to find whether liver enzymes level can be considered as the markers for HCV genotypes. MATERIALS AND METHODS: HCV-infected patients from different provinces of Iran (from August 2017 to March 2019) were enrolled. Nested reverse transcriptase polymerase chain reaction (PCR)-restriction fragment length polymorphism and real-time PCR were used to discover the genotypes. The infection transmission routes in the study population were investigated and recorded. Serum samples with equal viral loud from the patients without other liver disorders were recruited to explore the association between the genotypes and the liver biochemical markers. RESULTS: One thousand serum samples positive for the HCV genome were recruited. Genotype 3a was the most prevalent in the north, while genotype 1a was dominant at the center. In total, genotype 3a was the dominant genotype closely followed by 1a. Needle sharing by addicts was the most common transmission way of infection in Iran. This way was also the most for genotype 3a dissemination, and genotype 1a was transmitted mostly between family members. No significant association (P > 0.05) was observed between biochemical marker titers and HCV genotypes. CONCLUSION: A shift in the distribution profile of HCV genotypes, related to the transmission routes, has happened over time. Public awareness of the main routes of HCV transmission can break the cycle of transmission. Liver enzyme values in HCV-infected patients showed no relation with genotypes and only represented hepatocellular dysfunction.

Antibiofilm Activity of Kefir Probiotic Lactobacilli Against Uropathogenic Escherichia coli (UPEC).

BACKGROUND: Inhibition of biofilm formation is essential for the prevention and treatment of urinary tract infection. This study was aimed to identify the probiotic potential of Lactobacillus strains isolated from kefir and evaluate their antimicrobial and antibiofilm activities against Uropathogenic Escherichia coli (UPEC). METHODS: Twelve Lactobacillus strains were evaluated. Antimicrobial and antibiofilm activities of Cell Free Supernatant (CFS) of the Lactobacillus strains against UPEC isolates were evaluated by agar well diffusion method and crystal violet assay, respectively. Probiotic potential of selected isolates was assessed by analyzing their tolerance to acidic pH and bile salts, auto-aggregation ability, co-aggregation with Escherichia coli (E. coli) and hemolytic activity. The isolates were identified by phenotypic and 16S rRNA gene sequencing. RESULTS: The CFS of all lactobacilli strains was able to inhibit UPEC isolates even after neutralization. Four out of 12 isolates inhibited the biofilm formation by UPEC in the range 62-75%. The viability under acidic condition varied among the isolates ranging from 6-89.8%. All the isolates could tolerate the 0.3% bile and eight isolates showed the adaptation time of less than 1 hr. All the strains exhibited co-aggregation with E. coli. Auto-aggregation was highly correlated with co-aggregation of all lactobacilli strains with E. coli (r=0.889, p<0.001). The isolates with satisfactory probiotic potential and higher ability of biofilm inhibition and antibacterial activity belonged to the species Lactobacillus rhamnosus and Lactobacillus paracasei. CONCLUSION: All four selected probiotic strains exhibited antimicrobial and antibiofilm activities, which suggest potential applications for controlling or preventing infections caused by UPEC.

Synergistic activity of melittin with mupirocin: A study against methicillin-resistant S. Aureus (MRSA) and methicillin-susceptible S. Aureus (MSSA) isolates.

Methicillin-Resistant Staphylococcus aureus (MRSA) biofilms are involved in various nosocomial infections, being in the limelight of academic research. The current study aimed to determine the antimicrobial effects of melittin on planktonic and biofilm forms of S. aureus. Following the identification of MRSA and SCCmec types (using PCR method), Minimum Inhibitory Concentration (MIC), Minimum Bactericidal Concentration (MBC), and fractional inhibitory concentration index (FICi), for melittin and mupirocin were determined by broth microdilution assay. Melittin anti-biofilm activity was determined, using a microtiter-plate test (MtP) and scanning electron microscope (SEM) methods. The quorum sensing inhibitory activity of ½ MIC melittin was examined using a quantitative real-time RT-PCR method, and melittin cytotoxicity on Vero cells was examined by tetrazolium-based colorimetric (MTT) test. The Results of our study showed that Geometric means of MIC values of the melittin and mupirocin were 4.4 and 14.22 µg/ml respectively. The geometric mean of the FICi for both melittin-mupirocin was 0.75. No S. aureus biofilm was formed and hld gene (as a biofilm regulator) expression down-regulated. It seems that melittin can be useful in the treatment of S. aureus infections (especially MRSA) by reducing the hld expression. Furthermore, synergistic growth-inhibitory effects of mupirocin with melittin could be considered as a promising approach in the treatment of MRSA isolates.

Streptococcus mutans, sugar consumption, and oral hygiene: Which one has more effect on decayed, missing, and filled teeth (DMFT) score in Iranian adults?

BACKGROUND: Streptococcus mutans as an acid-generator of biofilm, sugar as a caries-conducive environment, and oral hygiene have been implicated as major etiological agents in dental caries. This study was designed to assess the association and impact of S. mutans, sugar consumption, and tooth brushing on decayed, missing, and filled teeth (DMFT) score in Iranian 20-30-year-old individuals and compare the effect of the three mentioned factors to find the most effective one. MATERIALS AND METHODS: In this cross-sectional study, 459 adults completed a Sugar Frequency Questionnaire and were examined for dental caries using DMFT index, sugar consumption level, and tooth brushing frequency per day. Saliva and plaque samples were collected, and the target population without Streptococcus sobrinus in their microbial oral community was selected using polymerase chain reaction technique. Data were analyzed by one-way analysis of variance and multiple linear regression tests (α = 0.05). RESULTS: Nearly 77.1% of the study population were harboring S. mutans. Mean DMFT of the population was 6.62. Mean comparison analysis showed that there is a strong relationship between S. mutans existence in mouth flora and DMFT scores (P < 0.0001). Multiple linear regression test showed higher percentage of S. mutans contribution (28.2%) in DMFT score changes than sugar consumption (3.6%) and tooth brushing (0.7%). CONCLUSION: This study provides a recent report from S. mutans frequency and DMFT score in Iranian adult population. It is also the first study that shows significantly higher impact of S. mutans in microbial population of mouth microflora on caries development than sugar consumption and oral hygiene. Accordingly, S. mutans screening program should be more highlighted in preventive strategies.

Antibiotic resistance pattern of Acinetobacter baumannii from burns patients: increase in prevalence of bla OXA-24-like and bla OXA-58-like genes.

BACKGROUND AND OBJECTIVES: Notwithstanding the increased prevalence of Acinetobacter baumannii drug-resistant isolates, treatment options are progressively limiting. This study aims to provide a recent report on antibiotic susceptibility in burn wound isolates of A. baumannii, and the importance of OXA beta-lactamases in carbapenem resistance. MATERIALS AND METHODS: The susceptibility levels to different antimicrobial categories were determined among 84 A. baumannii isolates from burn wound infection between 2016 and 2018. Multiplex PCR was used to detect OXA beta-lactamases genes, including bla OXA-51, bla OXA-23, bla OXA-24 and bla OXA-58. ISAba-1 association with bla OXA-51, bla OXA-23 and bla OXA-58 was detected by PCR mapping. RESULTS: All the isolates were determined as multidrug-resistant (MDR) and 69% as extensively drug-resistant (XDR). Different carbapenems MIC ranges (MIC50 and MIC90) were observed among the isolates harboring bla OXA-like genes and isolates with the OXA-24-like enzyme showed higher carbapenems MIC ranges. The prevalence of bla OXA-51-like, bla OXA-23-like, bla OXA-24-like and bla OXA-58-like were 100%, 53.57%, 41.66% and 30.95%, respectively. ISAba-1 insertion sequence was found to be upstream to bla OXA-23-like and bla OXA-58-like genes in 23 out of 45 (71.1%) bla OXA-23-like-positive and 4 out of 23 (15.3) bla OXA-58-like-positive isolates, respectively. CONCLUSION: Resistance to carbapenems as the last resort for treatment of A. baumannii infections is growing. This study, for the first time in Iran, has observed the increased frequency of bla OXA-24-like and bla OXA-58-like genes and found an association between ISAba-1 and bla OXA-58-like gene, which signifies the possible risk of increased diversity in OXA beta-lactamases and growth in carbapenem resistance.

Poly(I:C) adjuvant strongly enhances parasite-inhibitory antibodies and Th1 response against Plasmodium falciparum merozoite surface protein-1 (42-kDa fragment) in BALB/c mice.

Malaria vaccine development has been confronted with various challenges such as poor immunogenicity of malaria vaccine candidate antigens, which is considered as the main challenge. However, this problem can be managed using appropriate formulations of antigens and adjuvants. Poly(I:C) is a potent Th1 inducer and a human compatible adjuvant capable of stimulating both B- and T-cell immunity. Plasmodium falciparum merozoite surface protein 142 (PfMSP-142) is a promising vaccine candidate for blood stage of malaria that has faced several difficulties in clinical trials, mainly due to improper adjuvants. Therefore, in the current study, poly(I:C), as a potent Th1 inducer adjuvant, was evaluated to improve the immunogenicity of recombinant PfMSP-142, when compared to CFA/IFA, as reference adjuvant. Poly(I:C) produced high level and titers of anti-PfMSP-142 IgG antibodies in which was comparable to CFA/IFA adjuvant. In addition, PfMSP-142 formulated with poly(I:C) elicited a higher ratio of IFN-γ/IL-4 (23.9) and IgG2a/IgG1 (3.77) with more persistent, higher avidity, and titer of IgG2a relative to CFA/IFA, indicating a potent Th1 immune response. Poly(I:C) could also help to induce anti-PfMSP-142 antibodies with higher growth-inhibitory activity than CFA/IFA. Altogether, the results of the current study demonstrated that poly(I:C) is a potent adjuvant that can be appropriate for being used in PfMSP-142-based vaccine formulations.

Antibody responses and avidity of naturally acquired anti-Plasmodium vivax Duffy binding protein (PvDBP) antibodies in individuals from an area with unstable malaria transmission.

Plasmodium vivax remains an important cause of morbidity outside Africa, and no effective vaccine is available against this parasite. The P. vivax Duffy binding protein (PvDBP) is essential during merozoite invasion into erythrocytes, and it is a target for protective immunity against malaria. This investigation was designed to evaluate naturally acquired antibodies to two variant forms of PvDBP-II antigen (DBP-I and -VI) in malaria individuals (N = 85; median = 22 years) who were living in hypoendemic areas in Iran. The two PvDBP-II variants were expressed in Escherichia coli, and immunoglobulin G (IgG) isotype composition and avidity of naturally acquired antibodies to these antigens were measured using enzyme-linked immunosorbent assay (ELISA). Results showed that almost 32% of the studied individuals had positive antibody responses to the two PvDBP-II variants, and the prevalence of responders did not differ significantly (P > 0.05; χ(2) test). The IgG-positive samples exhibited 37.03% and 40.8% high-avidity antibodies for PvDBP-I and PvDBP-VI variants, respectively. Furthermore, high-avidity IgG1 antibody was found in 39.1% of positive sera for each examined variant antigen. The avidity of antibodies for both PvDBP variant antigens and the prevalence of responders with high- and intermediate-avidity IgG, IgG1, and IgG3 antibodies were similar in patients (P > 0.05; χ(2) test). Moreover, the prevalence of IgG antibody responses to the two variants significantly increased with exposure and host age. To sum up, the results provided additional data in our understanding of blood-stage immunity to PvDBP, supporting the rational development of an effective blood-stage vaccine based on this antigen.

Genetic mapping of the duffy binding protein (DBP) ligand domain of Plasmodium vivax from unstable malaria region in the Middle East.

The region II of Plasmodium vivax Duffy binding protein (PvDBP-II) contains the critical binding residues, which is a major target for development of naturally acquired immunity. Several studies showed sequence polymorphisms in PvDBP-II, which may inhibit antibodies recognition. Therefore, in this study the level of PvDBP-II polymorphism within and among P. vivax populations from re-emerged areas in north and endemic areas in south of Iran were evaluated by sequencing analysis in 75 isolates for the first time. Fourteen non-synonymous and one synonymous mutations were identified and none of the amino acid substitutions were directly involved in erythrocyte binding. Only 6 out of 14 detected mutations have been found among northern isolates, including D384G, R390H, N417K, L424I, W437R, and I503K. In total, two and nine different variants have been identified among northern and southern isolates, respectively. High association of the amino acid frequencies for codons 417, 437, and 503 were found among northern (85% for trio association and 100% for N417K with W437R), and southern (36% for trio association and 98% for N417K with W437R) samples. Polymorphisms at positions R308S, K371E, D384G, K386N, R390H, N417K, L424I, W437R, and I503K were identified from Iran and diverse geographic areas; however, mutation at position F306L was only reported from Asian malaria endemic areas. It is suggested that to develop polyvalent vaccine against P. vivax infection, it is better to incorporate the common and high prevalent allelic variants of the antigen that were reported from different malaria endemic regions.