RESUMO
Mastoparan B (MP-B) is an amphiphilic peptide with a potent antimicrobial activity against most Gram-negative bacteria. However, there is little information available on the inhibition of the Acinetobacter baumannii resistance-nodulation-cell-division (RND) efflux pump using this antimicrobial peptide. Here, we carried out a series of in-silico experiments to find the mechanisms underlying the anti-efflux activity of MP-B using a multi-drug resistant (MDR) strain of A. baumannii (AB). According to our findings, MP-B demonstrated a potent antibacterial activity against an MDR-AB (minimum inhibitory concentration [MIC] = 1 µg/mL) followed by a 20-fold reduction in the adeB gene expression in the presence of sub-MIC of this peptide. Using Groningen Machine for Chemicals Simulation (GROMACS) via PyMOL Graphical User Interface (GUI), (we observed that, the AdeB transporter had conserved helix-turn-helix regions and a tight pore rich in Phe and Ala residues. To understand how inhibition of the AdeB is achieved, we generated 20 apo-MP-B poses using the InterPep and SiteMap tools. The high-quality model was created by homology modeling and used for docking via AutoDock/Vina to identify the MP-B binding sites. We established that the most apo-MP-B formed H-bonds to the backbone of five amino acids in the Helix-5. As a result, the dihedral angles of the involved amino acids shift by 9.0-9.6 Ǻ, causing a change in the conformation of the AdeB protein. This led to helix conformation stereoisomerization and block the AdeB activity. MP-B presumably has dual mechanisms. (1) It blocks the AdeB transporter by changing its conformation. (2) MP-B influences the adeB gene expression by binding to G-protein which laterally controls efflux regulators like MarA, RamA, SoxS, and Rob proteins.
Assuntos
Acinetobacter baumannii , Acinetobacter baumannii/genética , Acinetobacter baumannii/metabolismo , Proteínas de Bactérias/química , Antibacterianos/química , Proteínas de Membrana Transportadoras/química , Testes de Sensibilidade Microbiana , Simulação de Dinâmica Molecular , Expressão GênicaRESUMO
Clostridioides difficile is one of the major causatives of nosocomial infections worldwide. Antibiotic-associated diarrhea, pseudomembranous colitis, and toxic megacolon are the most common forms of C. difficile infection (CDI). Considering the high antibiotic resistance of C. difficile isolates and the low efficacy of immunization with toxin-related vaccines, we suggested that surface-exposed and secreted proteins could be considered as potential immunogenic targets against CDI. Various immuninformatics databases were used to predict antigenicity, allergenicity, B-cell epitopes, MHC-II binding sites, conserved domains, prevalence and conservation of proteins among the most common sequence types, molecular docking, and immunosimulation of immunogenic targets. Finally, 16 proteins belonging to three functional groups were identified, including proteins involved in the cell wall and peptidoglycan layer (nine proteins), flagellar assembly (five proteins), spore germination (one protein), and a protein with unknown function. Molecular docking results showed that among all the mentioned proteins, WP_009892971.1 (Acd) and WP_009890599.1 (a C40 family peptidase) had the strongest interactions with human Toll-like receptor 2 (TLR-2) and TLR-4. This study proposes a combination of C. difficile toxoid (Tcd) and surface-exposed proteins such as Acd as a promising vaccine formulation for protection against circulating clinical strains of C. difficile.
Assuntos
Clostridioides difficile , Infecções por Clostridium , Clostridioides , Clostridioides difficile/genética , Infecções por Clostridium/prevenção & controle , Humanos , Simulação de Acoplamento Molecular , Técnicas de Hibridização SubtrativaRESUMO
OBJECTIVES: The prevalence of multiple sclerosis (MS) in the Persian Gulf countries has been significantly increasing during the past decades. This study was conducted for investigating the prevalence and incidence of MS in Northeast Iran (Khorasan Razavi province). METHODS: This cross-sectional study was conducted during 1 January 1988 and 23 September 2018. All patients with a clinically definite diagnosis of MS according to the McDonald criteria (2005) and MRI along with the medical diagnosis, recorded in the Khorasan MS society, were considered for calculation of crude and age-standardized prevalence, and incidence rates of MS. The periodic incidence rates were calculated based on the year of onset of MS. Also, we calculated gender ratios for prevalence and incidence rates. RESULTS: The mean age-standardized prevalence and incidence rates of MS in the Khorasan Razavi were 8.69 (95% CI 8.05-9.41) per 100,000 (3.99 (95% CI 3.39-4.74) for males, 13.49 (95% CI 12.37-14.76) for females). Age-standardized prevalence was 48.87 (95% CI 48.37-49.35) per 100,000 (22.47 (95% CI 22.01-22.93) for males, 75.65 (95% CI 74.80-76.51) for females). Also, the mean incidence and prevalence for Mashhad County as capital of province were 11.38 and 59.09 per 100,000 populations, respectively. The female/male ratio was 3.33 for all age groups. CONCLUSION: Our results showed that this region is a high-risk area for MS like central region of Iran. Our results revealed that the prevalence and incidence of MS in the study area have increased during the recent decades with a sharp slope.
Assuntos
Esclerose Múltipla , Estudos Transversais , Feminino , Humanos , Incidência , Irã (Geográfico)/epidemiologia , Masculino , Esclerose Múltipla/epidemiologia , PrevalênciaRESUMO
Carbapenem-resistant Acinetobacter baumannii strains are increasing worldwide. In this study, samples were collected from hospital environments, extra hospital environments, and fecal carriages. 76% (89/117) of bacterial isolates were detected as A. baumannii strains. The imipenem resistance in the hospital environment, fecal carriages, extra hospital environments, and clinical isolates was 37.7% (17/45), 100% (9/9), 0% (0/45), and 92.9% (92/99), respectively. The blaVIM and blaOXA-23 were detected in 6.6% (3/45) and 2.2% (1/45) of strains isolated from hospital environments. Interestingly, strains isolated from fecal carriages had blaVIM, blaOXA-23, and blaIMP genes which resembled carbapenem resistance genes in clinical strains. The structure of clonal relatedness among all non-clinical isolates was as follows: CC2, 37% (33/89); CC1, 22.4% (20/89); CC3, 12.3% (11/89); CC25, 7.8% (7/89); CC10, 4.4% (4/89) and CC15, 2.2% (2/89). Comparison of clonal relatedness among clinical and non-clinical isolates indicated that widespread clones including CC2, CC3, and CC10 were common clonal complexes between two categories.
Assuntos
Infecções por Acinetobacter , Acinetobacter baumannii , Infecções por Acinetobacter/tratamento farmacológico , Infecções por Acinetobacter/epidemiologia , Infecções por Acinetobacter/microbiologia , Acinetobacter baumannii/genética , Antibacterianos/farmacologia , Proteínas de Bactérias/genética , Carbapenêmicos/farmacologia , Hospitais , Humanos , Testes de Sensibilidade Microbiana , beta-Lactamases/genéticaRESUMO
The accurate identification of Acinetobacter spp. is challenging due to their high phenotypic and biochemical similarities. Because clinical relevance and antibiotic susceptibility are significantly different among different genomic species of Acinetobacter, the exact identification of A. baumannii is necessary and it can help us prevent inappropriate antibiotic use and inferior clinical care. This project employed a sequence-specific PCR assay for the rpoB region in A. baumannii to distinguish it from non-Acinetobacter baumannii Acinetobacter species. Moreover, a duplex PCR assay was used to detect blaOXA-51-like and gluconolactonase genes as a second identification method. In this study, 210 isolates of Acinetobacter spp. were considered and identified by PCR-sequencing of rpoB gene as a reference test. PCR-sequencing of rpoB revealed that 179 isolates were A. baumannii and 31 were non- A. baumannii Acinetobacter strains. PCR amplification targeting the rpoB gene as the first method, detected 182 isolates of A. baumannii, while duplex PCR assay confirmed 163 isolates as A. baumannii. Data analysis indicated that the sensitivities of sequence-specific PCR of the rpoB gene and duplex PCR assay were 100% and 91.06%, respectively, while specificities were 91.18% and 100%, respectively. Given the data, it was revealed that these two methods showed a reasonable potential for the accurate identification of A. baumannnii from non- A. baumannii species. Sequence-specific PCR assay for the rpoB gene and duplex PCR assay for blaOXA-51-like and gluconolactonase genes are rapid, reliable and cost-effective methods which can be used in clinical laboratories for the accurate identification of A. baumannii.
Assuntos
Infecções por Acinetobacter , Acinetobacter baumannii , Infecções por Acinetobacter/diagnóstico , Acinetobacter baumannii/genética , Humanos , Laboratórios Clínicos , Testes de Sensibilidade Microbiana , Reação em Cadeia da Polimerase , beta-LactamasesRESUMO
BACKGROUND: Resistant Helicobacter pylori to commonly used antimicrobial agents are associated with severe upper gastrointestinal disorders. To provide an epidemiological picture of H pylori and characterize the resistance pattern and genetic variation of clinical isolates, stomach biopsies from patients with functional dyspepsia were evaluated in northeast of Iran. MATERIALS AND METHODS: In this study, 80 patients were recruited. Finally, fifty H pylori strains were isolated from antrum and corpus biopsies by culturing on Columbia agar. All strains were identified by standard laboratory procedures. Susceptibility testing of antibiotics was performed using minimum inhibitory concentration test. Allele-specific primer (ASP)-PCR of 23S rRNA which associated with clarithromycin resistance was done among resistant strains. Moreover, cagA gene and polymorphism in vacA were detected. Random amplified polymorphic DNA polymerase chain reaction (RAPD-PCR) was applied to investigate the genetic variations among all strains. RESULTS: Antibiotic resistance pattern of H pylori strains was as follows: 68% (34/50) to metronidazole, 50% (25/50) to rifampicin, 30% (15/50) to amoxicillin, 28% (14/50) to levofloxacin, 22% (11/50) to clarithromycin, and 16% (8/50) to tetracycline. Multidrug-resistant strains were observed in 19 strains (38%). ASP-PCR of 23S rRNA showed four strains had A2143G mutation, six strains had A2142G mutation, and one strain had a Wt+A2143G mutation. Amplification of virulence-associated genes revealed that cagA was present in 27 isolates (54%) and vacA in 36 isolates (72%). The most common genotype of H pylori was vacA s1am2 (40%) followed by vacA s2m2 (14%), vacA s1am1 (12%), vacA s1bm1 (4%), and vacA s1bm2 (2%). DNA fingerprinting pattern indicated a high heterogeneity among isolated strains. CONCLUSION: An alarming level of resistance to metronidazole and rifampicin and high heterogeneity among H pylori isolates highlighted the importance of continued monitoring of antimicrobial susceptibility and epidemiological surveillance of this pathogen.
Assuntos
Farmacorresistência Bacteriana/genética , Farmacorresistência Bacteriana Múltipla/genética , Infecções por Helicobacter , Helicobacter pylori , Virulência/genética , Adulto , Antígenos de Bactérias/genética , Proteínas de Bactérias/genética , Biópsia , Feminino , Variação Genética , Infecções por Helicobacter/tratamento farmacológico , Infecções por Helicobacter/epidemiologia , Helicobacter pylori/efeitos dos fármacos , Helicobacter pylori/genética , Helicobacter pylori/isolamento & purificação , Humanos , Irã (Geográfico)/epidemiologia , Masculino , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , RNA Ribossômico 23S/genética , Técnica de Amplificação ao Acaso de DNA Polimórfico , Estômago/microbiologiaRESUMO
Clostridioides difficile and Staphylococcus aureus are two well-known pathogens both causing hospital- and community-acquired infections. However, their intestinal coexistence was not well investigated in inflammatory bowel disease (IBD). Herein, we explored the prevalence of C. difficile, S. aureus and their coexistence in the gut of Iranian patients with IBD. Fecal and colon specimens were obtained from 70 outpatients with underlying IBD, and investigated for the presence of C. difficile and S. aureus. C. difficile isolates were characterised by CE-ribotyping. PCR was used for detection of toxin-encoding genes of C. difficile and S. aureus isolates. The antimicrobial susceptibility testing of C. difficile and S. aureus isolates were examined by agar dilution and Kirby-Bauer disk diffusion methods, respectively. Totally, C. difficile and S. aureus were detected in only 5.7% and 15.8% of IBD flares. Coexistence of C. difficile and S. aureus was detected in 5.7% of IBD flares. Two different C. difficile ribotypes including RT 126 and RT 017 were identified showing toxin profiles of tcdA+B+/cdtA+B+ and tcdA+B+, respectively. In S. aureus isolates, only positivity for the presence of sea enterotoxin was detected. C. difficile isolates were susceptible to metronidazole, ceftazidime and fidaxomicin. The highest resistance of S. aureus isolates was observed against penicillin (92.3%), following amoxicillin-clavulanate (38.5%) and amikacin (30.8%). Our findings demonstrated that patients with IBD flare are more sensitive to acquire coinfection of C. difficile and S. aureus than remission. However, more robust data is required to study the crosstalk between these enteric infections and their clinical relevance in patients with IBD flare.
Assuntos
Clostridioides difficile , Coinfecção/microbiologia , Doenças Inflamatórias Intestinais/etiologia , Mucosa Intestinal/microbiologia , Pacientes Ambulatoriais , Staphylococcus aureus , Adolescente , Adulto , Idoso , Antibacterianos/farmacologia , Biópsia , Criança , Pré-Escolar , Clostridioides difficile/efeitos dos fármacos , Coinfecção/complicações , Suscetibilidade a Doenças , Fezes/microbiologia , Feminino , Humanos , Lactente , Doenças Inflamatórias Intestinais/diagnóstico , Doenças Inflamatórias Intestinais/epidemiologia , Mucosa Intestinal/patologia , Irã (Geográfico)/epidemiologia , Masculino , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , Prevalência , Vigilância em Saúde Pública , Staphylococcus aureus/efeitos dos fármacos , Adulto JovemRESUMO
Successful clones of Acinetobacter baumannii cause a variety of nosocomial infections through serum resistance, biofilm formation, and antimicrobial resistance as virulence capabilities. Fifty clinical isolates of multidrug-resistant (MDR) A. baumannii were analyzed for clonal relatedness, serum resistance, biofilm formation, and in vivo assays. Furthermore, some virulence genes, sequence variation of ompA, and its expression were studied. The MLST (multilocus sequence typing) results showed that there were three sequence types among MDR isolates including ST2 (64%, 32/50), ST513 (30%, 15/50), and ST1 (6%, 3/50). The data showed that the clinical isolates recovered from sputum had mostly high biofilm-formation capacity, while isolates recovered from host interior fluids had high serum resistance. The results of PCR assays and in silico analysis represented patterns of virulence genes and even ompA sequence variations among MDR isolates which were clonally dependent. While quantitative reverse transcription-polymerase chain reaction (qRT-PCR) analysis showed that bacteremia-producing strains in C57/BL6 mice significantly overexpress ompA (P < 0.05) and have a direct relation with the level of IL-6 in bloodstream of mice. Moreover, the expressions of ompA among indistinguishable clones (ST2 or ST513) were clonally independent.
Assuntos
Infecções por Acinetobacter/microbiologia , Acinetobacter baumannii/crescimento & desenvolvimento , Acinetobacter baumannii/patogenicidade , Proteínas da Membrana Bacteriana Externa/biossíntese , Farmacorresistência Bacteriana Múltipla , Tipagem de Sequências Multilocus , Fatores de Virulência/biossíntese , Infecções por Acinetobacter/patologia , Acinetobacter baumannii/classificação , Acinetobacter baumannii/isolamento & purificação , Animais , Biofilmes/crescimento & desenvolvimento , Atividade Bactericida do Sangue , Modelos Animais de Doenças , Perfilação da Expressão Gênica , Genótipo , Humanos , Camundongos Endogâmicos C57BL , Reação em Cadeia da Polimerase em Tempo Real , Sepse/microbiologia , Sepse/patologia , Escarro/microbiologia , VirulênciaRESUMO
Klebsiella pneumoniae is among the most important causes of urinary tract infection (UTI). The aim of this study was to investigate the prevalence and correlation of antibiotic resistance with virulence characteristics and genetic diversity in K. pneumoniae isolated from UTIs in Iran. Phenotypic tests and antibiotic susceptibility were carried out on the isolates. Detection of the virulence and extended-spectrum ß-lactamase (ESBL) genes was performed by polymerase chain reaction. Pulsed-ï¬eld gel electrophoresis (PFGE) was used for exploring the genomic relatedness. Hemolysin, biofilm, and hypermucoviscosity formation were observed in 87.1%, 86.4%, and 12.1% of isolates, respectively. The antibiotic resistance rate of K. pneumoniae isolates ranged from 12.1% for meropenem to 100% for amoxicillin. The prevalence of virulence genes ranged from 1.4% for cnf-1 to 100% for mrkD, fimH, kpn, and entB genes. In this study, 91.7%, 33.3%, and 4.2% of phenotypically ESBL-producers were positive for blaCTX-M, blaTEM, and blaSHV genes, respectively. An association was observed between the presence of traT, fyuA, or cnf-1 genes with antibiotic resistance. Two clone types were obtained by PFGE that indicate different K. pneumoniae clones in community- and hospital-acquired UTIs. The findings of this study are valuable in development of treatment strategies against UTIs in Iran.
Assuntos
Infecções Comunitárias Adquiridas/microbiologia , Infecção Hospitalar/microbiologia , Farmacorresistência Bacteriana , Variação Genética , Infecções por Klebsiella/microbiologia , Klebsiella pneumoniae/isolamento & purificação , Infecções Urinárias/microbiologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Técnicas Bacteriológicas , Infecções Comunitárias Adquiridas/epidemiologia , Infecção Hospitalar/epidemiologia , Feminino , Técnicas de Genotipagem , Humanos , Irã (Geográfico)/epidemiologia , Infecções por Klebsiella/epidemiologia , Klebsiella pneumoniae/classificação , Klebsiella pneumoniae/efeitos dos fármacos , Klebsiella pneumoniae/genética , Masculino , Pessoa de Meia-Idade , Prevalência , Infecções Urinárias/epidemiologia , Virulência , Adulto JovemRESUMO
There are numerous evidence supporting the association between Helicobacter pylori (H. pylori) infection and the occurrence of cognitive deficits in humans. In this regard, treatment of H. pylori infection has been suggested as an effective strategy to decelerate the neurodegenerative processes of memory deficits in AD patients. Numerous studies support the beneficial effects of probiotics on various pathological conditions, particularly cognitive deficits, however, this concern has not been addressed in relation to the memory impairment induced by H. pylori infection. In the present study, we aimed to reveal whether oral administration of two bacterial probiotics (including Lactobacillus rhamnosus and Lactobacillus plantarum), could ameliorate H. pylori-induced memory deficits at behavioral level in rats. Besides, cellular mechanisms were investigated by biochemical methods to find out how probiotic effects are mediated in hippocampal circuitry. Male Wistar rats were infected by H. pylori for 3 consecutive days, then probiotic treatment was done for the next 3 days and after a drug-free period (12 days), animals were assessed by Morris Water Maze and Novel Object Recognition tests. Finally, rats were euthanized by CO2 and hippocampal tissues were excised for biochemical measurements. Results indicated that H. pylori infection markedly impairs memory function in rats which is associated with alterations of oxidative, inflammatory, neurotrophic, and cholinergic markers. Interestingly, treatment with either of the probiotics alone or in combination, significantly improved the H. pylori-induced memory deficits and this was associated with restoration of balance in biochemical factors within the hippocampal neurons.
Assuntos
Infecções por Helicobacter , Helicobacter pylori , Probióticos , Humanos , Ratos , Masculino , Animais , Ratos Wistar , Infecções por Helicobacter/microbiologia , Infecções por Helicobacter/patologia , Infecções por Helicobacter/terapia , Probióticos/farmacologia , Transtornos da Memória/etiologia , Transtornos da Memória/terapia , Administração OralRESUMO
Echinococcus granulosus sensu lato (E. granulosus s.l.) is a zoonotic parasite, causing cystic echinococcosis in humans. In the present study, prevalence and genotypes of E. granulosus s.l. was assessed in stools collected from 244 dogs including 138 stray and 106 domestic animals using high resolution melting curve (HRM) method. Initially, to detect taeniid eggs in feces, all samples were examined using the formalin-ether techniques. Genomic DNA was extracted from the positive samples and E. granulosus s.l. was differentiated from other Taeniidae parasites using SSU-rDNA gene and E. granulosus s.l. was analyzed for genotyping using HRM based on the cox1 gene. In total, 12.7% (31/244) of the samples were positive for Taeniidae eggs. In addition, among the positive samples, 77.4% (24/31) were positive for E. granulosus s.l.. In details, 11.3% (12/106) of the domestic dogs and 8.7% (12/138) of the stray dogs were positive for E. granulosus s.l.. The results of HRM analysis showed that all E. granulosus s.l. isolates were G1 strain. Findings of the present study indicated a considerable prevalence of E. granulosus G1 among dogs in the northeast of Iran and imply a serious risk of transmitting to humans and livestock.
Assuntos
Doenças do Cão , Equinococose , Echinococcus granulosus , Doenças dos Ovinos , Ovinos , Cães , Animais , Humanos , Echinococcus granulosus/genética , Irã (Geográfico)/epidemiologia , Equinococose/epidemiologia , Equinococose/veterinária , Equinococose/diagnóstico , Genótipo , Reação em Cadeia da Polimerase/veterinária , Doenças do Cão/parasitologiaRESUMO
Adolescence is a critical life period during which significant neurodevelopmental changes occur within the central nervous system. Consistently, substance abuse in this stage has been found to induce persistent changes in brain responsiveness to future drug challenges. Nowadays, heavy episodic alcohol consumption during adolescence, also known as binge-drinking behavior, is a growing concern in modern societies. On the other hand, alcohol is well known to act as a gateway drug, that is, it promotes the individual's craving for consumption of other drugs of abuse. With this in mind, we aimed to assess whether adolescent ethanol exposure could alter the development of tolerance and dependence to morphine, as an available common opioid drug. Tail flick test was used to measure thermal nociceptive changes in adult male Wistar rats undergone ethanol/vehicle exposure during adolescence. Furthermore, morphine withdrawal syndrome was induced by naloxone injection, and behavioral signs were recorded for 20 min. It was found that adolescent ethanol intake facilitates morphine analgesic tolerance and decreases baseline latency; however, the severity of dependence is not significantly altered. Moreover, we found that 15 days of treatment with omega-3 fatty acids (O3) prevents the mentioned ethanol-induced changes suggesting a therapeutic potential for this compound. O3 supplementation, as an inexpensive and noninvasive method, may assist the clinicians to reverse the adverse effect of alcohol binge drinking on adolescents' brains and to reduce the vulnerability to drug exposure in adulthood. (PsycInfo Database Record (c) 2023 APA, all rights reserved).
Assuntos
Ácidos Graxos Ômega-3 , Morfina , Ratos , Animais , Masculino , Etanol , Ratos Wistar , Analgésicos , Consumo de Bebidas AlcoólicasRESUMO
Porphyromonas gingivalis is a primary causative agent of chronic periodontitis. Moreover, it leads to several systemic diseases, including rheumatoid arthritis, cardiovascular, neurodegenerative, and Alzheimer's diseases. It seems that the development of a vaccine against this bacterium is necessary. Thus, this study decided to identify novel immunogenic targets and developed multiple epitope-based vaccines against P. gingivalis. For this purpose, the pan/core-proteome of this bacterium was studied, and the suitable vaccine targets were selected based on different properties, including exposed localization of proteins, antigenicity, non-allergenicity, non-similarity to host proteome, stability, B-cell epitopes and MHC II binding sites, sequence conservation, molecular docking, and immune simulation. Through the quartile scoring method, 12 proteins with ≥ 20 scores were considered as suitable immunogenic targets. The results of the protein domain and functional class search showed that most of the immunogenic proteins were involved in the transport and metabolism of inorganic ions and lipids. In addition, two unknown function proteins, including WP_004584259.1 and WP_099780539.1 were detected as immunogenic targets. Three constructions carrying multi-epitopes were generated including Naked, LCL, and as chimeric structures. Among them, FliC chimeric protein had the strongest affinity to the human TLR2, 4, and 6, while the LCL platform represented the highest level of immune stimulation response. The obtained results from this study revealed new insights into prophylactic routes against P. gingivalis by introducing novel immunogenic targets. However, further investigations, including site-directed mutation and immunoassay are needed to confirm the pathogenic role and protectivity of these novel proteins.
Assuntos
Porphyromonas gingivalis , Vacinologia , Biologia Computacional/métodos , Epitopos de Linfócito B , Epitopos de Linfócito T , Humanos , Simulação de Acoplamento Molecular , Proteoma , Vacinas de Subunidades Antigênicas , Vacinologia/métodosRESUMO
Carbapenem resistance in Enterobacterales is a major and persistent public health problem worldwide. In current research, we present data of 96 Enterobacterales species collected from a clinical hospital in Isfahan, Iran. The bacterial identification was performed by standard biochemical tests and API 20E methods. Agar disk diffusion assay was performed to determine the phenotypic antibiotic resistance of strains. Polymerase chain reaction (PCR) was carried out to detect carbapenemase genes. In this manuscript, multiple antimicrobial resistance phenotype such as multiple carbapenem resistance determinants were detected. The data would provide important information on distribution of carbapenemase genes of those pathogenic bacteria in Iran.
RESUMO
Background: There is limited information on the three-dimensional (3D) prediction and modeling of the colistin resistance-associated proteins PmrA/B TCS in Acinetobacter baumannii. We aimed to evaluate the stereochemical structure and domain characterization of phosphotransferase membrane receptor A/B (PmrA/B) in an A. baumannii isolate resistant to high-level colistin, using bioinformatics tools. Methods: The species of the isolate and its susceptibility to colistin were confirmed by PCR-sequencing and minimum inhibitory concentration assay, respectively. For 3D prediction of the PmrA/B, we used 16 template models with the highest quality (e-value <1 × 10−50). Results: Prediction of the PmrA structure revealed a monomeric non-redundant protein consisting of 28 α-helices and 22 ß-sheets. The PmrA DNA-binding motif displayed three antiparallel α-helices, followed by three ß-sheets, and was bond to the major groove of DNA by intermolecular van der Waals bonds through amino acids Lys, Asp, His, and Arg, respectively. Superimposition of the deduced PmrA 3D structure with the closely related PmrA protein model (GenBank no. WP_071210493.1) revealed no distortion in conformation, due to GluâLys substitution at position 218. Similarly, the PmrB protein structure displayed 24 α-helices and 13 ß-sheets. In our case, His251 acted as a phosphate receptor in the HisKA domain. The amino acid substitutions were mainly observed at the putative N-terminus region of the protein. Furthermore, two substitutions (Lys21âSer and Ser28âArg) in the transmembrane domain were detected. Conclusion: The DNA-binding motif of PmrA is highly conserved, though the N-terminal fragment of PmrB showed a high rate of base substitutions. This research provides valuable insights into the mechanism of colistin resistance in A. baumannii.
Assuntos
Acinetobacter baumannii/isolamento & purificação , Acinetobacter baumannii/fisiologia , Proteínas de Bactérias/metabolismo , Colistina/farmacologia , Farmacorresistência Bacteriana/efeitos dos fármacos , Acinetobacter baumannii/efeitos dos fármacos , Sequência de Aminoácidos , Proteínas de Bactérias/química , DNA Bacteriano/metabolismo , Modelos Moleculares , Ligação Proteica , Domínios ProteicosRESUMO
BACKGROUND & AIMS: Clostridioides difficile (C. difficile) has been identified as the leading cause of antibiotic associated diarrhea (AAD). Co-carriage of an intact pathogenicity locus (PaLoc) with binary toxin genes in C. difficile strains seems to be linked with severe disease outcomes in the infected patients. Epidemiology of C. difficile infection (CDI) in hospital setting and knowledge about their genetic context help us to decrease the morbidity, mortality, and costs associated with Clostridioides difficile infection. In the present study was aimed to characterize genetic diversity of PaLoc among different C. difficile strains isolated from hospitalized patients and carriage of cytolethal distending toxin gene (cdt) in different hospitals. METHOD: C. difficile strains were isolated from stool samples of inpatients referred to a reference laboratory from different hospitals and also outpatients with diarrhea, during 2008-2011. DNA was extracted from pure culture of the bacterium and PCR was performed for tcdA, tcdB, tcdE, tcdC, tcdD, and cdu2 genes. Carriage of two binary toxin genes cdtA, cdtB was also determined in these strains. To find clonal strains, similarity of genotypes and integrity of PaLoc among the isolates was compared in each hospital. RESULTS: The intact PaLoc was found most frequently among the isolates in the outpatients (19/51, 37.2%, Group I), while incomplete PaLoc found mostly in patients who were hospitalized in the infectious diseases and internal diagnosis wards. tcdA and tcdB genes were detected in different combinations among the studied strains. These strains showed tcdA+B+, tcdA+B-, and tcdA-B+ genotypes in a frequency of 76.4% (39/51), 7.8% (4/51), and 17.6% (9/51), respectively. Analysis of gene composition of the PaLoc showed 19 distinct genotypes among the 51 strains. Accordingly, 38 strains were classified mainly into 6 regular groups, while the remaining strains showed heterogeneous patterns. tcdC-/tcdD- constituted the most common genotypic group among the strains with partial PaLoc (7/51, 13.7%). A hypertoxigenic genotype, tcdC-/tcdA+/tcdB+, was detected in 2 strains (2/51, 3.9%). The intact genotype was also detected in a C. difficile isolate from outpatients. Cdt encoding genes toxins was observed in low numbers of the strains (7/52, 13.5%). All of cdtA+B+ strains were belonged to PaLoc group 1 (intact genotype). Statistical analyses showed no correlation between particular genotypes and special wards of the hospitals (p value>0.05). CONCLUSION: Collectively, our results showed diversity of C. difficile strains in most wards of the studied hospitals. Diversity of PaLoc genotypes in the strains that isolated from the same wards proposed endogenous routes of the infection, as common cause of CDI in these patients.
Assuntos
ADP Ribose Transferases/genética , Proteínas de Bactérias/genética , Clostridioides difficile/genética , Clostridioides difficile/patogenicidade , Enterocolite Pseudomembranosa/epidemiologia , Fatores de Virulência/genética , Toxinas Bacterianas/genética , Proteínas de Ligação a DNA/genética , Enterotoxinas/genética , Feminino , Técnicas de Genotipagem , Hospitais , Humanos , Irã (Geográfico)/epidemiologia , Masculino , Epidemiologia Molecular , Proteínas Repressoras/genéticaRESUMO
OBJECTIVES: Carbapenem-resistant Klebsiella pneumoniae infections are associated with increased rates of treatment failure and death. Several studies have reported isolates with a combined hypervirulent and antimicrobial-resistant phenotype. METHODS: In this study, the molecular characteristics of hypervirulent K. pneumoniae (hvKP) isolated from mechanically-ventilated patients admitted to a toxicological intensive care unit (ICU) in Tehran, Iran, were examined. String test, antimicrobial susceptibility testing, virulence factors analysis and plasmid replicon typing were performed. The clonal relatedness of the isolates was analysed by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). RESULTS: hvKP accounted for 9.4% (5/53) of K. pneumoniae isolated from ventilator-associated pneumonia among patients admitted to the ICU with acute drug poisoning. The mortality rate was 7.5% (4/53) among K. pneumoniae-infected patients. All fatal K. pneumoniae were hvKP isolates, were resistant to imipenem and harboured an aacA7, blaVIM-2 and dhfrI cassette arrangement in a class 1 integron. The isolates were shown to be ST23 (Pasteur scheme) and exhibited similar PFGE patterns. Plasmid analysis revealed a class 1 integron harbouring blaVIM-2 located on an ca. 45-kb IncN plasmid. CONCLUSION: Here we describe the emergence of VIM-2-producing hvKP serotype K1/ST23 in an outbreak with high mortality in a hospital toxicological ICU. It appears that we must alert and prepare the hospital's surveillance system for the appearance, expansion and clinical importance of new K. pneumoniae clones associated with high antimicrobial resistance and robust virulence capabilities.
Assuntos
Infecções por Klebsiella/microbiologia , Klebsiella pneumoniae/isolamento & purificação , Pneumonia Associada à Ventilação Mecânica/microbiologia , Adulto , Antibacterianos/farmacologia , Estudos Transversais , Farmacorresistência Bacteriana , Feminino , Humanos , Integrons , Irã (Geográfico) , Infecções por Klebsiella/mortalidade , Klebsiella pneumoniae/efeitos dos fármacos , Klebsiella pneumoniae/genética , Klebsiella pneumoniae/patogenicidade , Masculino , Pessoa de Meia-Idade , Tipagem de Sequências Multilocus , Respiração Artificial/efeitos adversos , Ventiladores Mecânicos/efeitos adversos , Ventiladores Mecânicos/microbiologia , VirulênciaRESUMO
Acinetobacter baumannii is an important nosocomial pathogen which causes a wide range of infections. In this study, we addressed the role of class 1 integron, ISAba1 and ISAba125 associated with antimicrobial resistance in 72 clinical isolates of A. baumannii collected from clinical settings in Tehran, Iran. Moreover, to study the clonal relatedness of strains, repetitive extragenic palindromic-PCR (rep-PCR) assay was carried out. PCR revealed that blaOXA-51-like, blaOXA-23-like, blaOXA-24/40-like, blaOXA-58-like, blaNDM, integrase gene (intI1), ISAba1, and ISAba125 were present in 86.11% (62/72), 84.72% (61/72), 30.55% (22/72), 0% (0/72), 0% (0/72), 58.33% (42/72), 97.22% (70/72), and 65.27% (47/72) of the strains, respectively. Sequencing of 39 internal variable regions of class 1 integrons showed seven gene cassette arrays, including aadA4-catB8-aadA1 (2.77%), aadA1-aadA4 (1.38%), aacC4-aadA1 (2.77%), aacC4 (22.22%), aadA1 (13.88%), aadA4 (5.55%), and catB8 (5.55%). We detected ISAba1 in the upstream of blaOXA-23-like, blaOXA-51-like, and blaADC in 54.16% (39/72), 9.72% (7/72), and 56.94% (41/72) of the strains, respectively. Whereas, there was a low frequency of disruptions in carO and dacD genes: 5.55% (4/72) and 4.16% (3/72). Rep-PCR analysis revealed that the isolates were genetically diverse. However, Cl-12 and Cl-15 were the largest clusters and they were recovered from various hospitals. Our analysis showed the high rates of class 1 integrons as a repertoire of aminoglycoside-modifying enzymes. It seems that linkages of ISAba1-blaOXA-23-like and ISAba1-blaOXA-69, and disruptions in carO or dacD can develop resistance to carbapenems among clinical isolates of A. baumannii.
Assuntos
Acinetobacter baumannii/genética , Proteínas de Bactérias/genética , Elementos de DNA Transponíveis/genética , Variação Genética/genética , Integrons/genética , Acinetobacter baumannii/efeitos dos fármacos , Antibacterianos/farmacologia , Carbapenêmicos/farmacologia , Farmacorresistência Bacteriana Múltipla/genética , Humanos , Irã (Geográfico) , Testes de Sensibilidade Microbiana/métodosRESUMO
OBJECTIVE: Diabetes mellitus (DM) is the most common metabolic disorder that defined by chronic hyperglycemia for the deficiency in insulin secretion or resistance. Hyperglycemia could induce non-enzymatic glycation of proteins. It has been suggested that some traditional plants can improve blood glucose and inhibit glycation process. This work evaluates and compares the anti-glycation activities of four Iranian plant extracts in vitro. METHODS: The methanolic extract of "Fumaria officinalis, Stachys lavandulifolia, Salvia hydrangea and Rosa Damascene" was prepared in three different concentrations. Phenolic, flavonoids content and antioxidant activity were evaluated. The multistage glycation markers-fructosamines (early stage), protein carbonyls (intermediate stage) and ß aggregation of albumin were investigated in the bovine serum albumin (BSA)/ glucose systemt. RESULTS: All plants showed the high potency of scavenging free radicals and glycation inhibition in the following order: Fumaria officinalis> Rosa Damascene> Stachys lavandulifolia > Salvia hydrangea. There was a significant correlation between antioxidant and anti-glycation activity. Also, the antioxidant and anti-glycation capacity of extracts correlated with total phenolic and flavonoids content. CONCLUSION: Our findings demonstrated that the studied plants are good sources of anti-glycation and antioxidant compounds and, these properties can primarily attributable to phenolics, particularly flavonoids.
RESUMO
PURPOSE: Acinetobacter baumannii-calcoaceticus complex (ABC) make a great burden on health-care systems due to hospital-acquired infections and antibacterial resistance. Aminoglycoside in combination with other antibacterials used as treatment options. However, ABC species overcome this class of antibacterials in different ways. This study provides a comprehensive report on the distribution of aminoglycoside modifying enzymes (AMEs) and 16S rRNA methylase in Acinetobacter baumannii and Acinetobacter nosocomialis isolated from various provinces in Iran. METHODS: During six month of study, from eight referral centers in seven provinces across the country, Iran, 178 A. baumannii and 43 A. nosocomialis isolates were collected. The minimum inhibitory concentration of amikacin, gentamicin, netilmicin, kanamycin and tobramycin were measured by microbroth dilution method. AMEs and 16S rRNA methylase variants were sought by PCR. RESULTS: High rates of resistance were seen in all centers. MIC50 and MIC90 for all A. baumannii and A. nosocomialis isolates from different centers wereâ¯>â¯512â¯mg/L. The most frequent AME was ant(3â³)-Ia (aadA1) in both of A. baumannii (74.1%) and A. nosocomialis (86%). armA was detected in A. baumannii and A. nosocomialis at the frequency of 41.6% and 67.4%, respectively. rmtA, B, C, D, aac(3)-Ia (aacC1) and aac(6')-Im were not detected, neither in A. baumannii nor A. nosocomialis. Moreover, aac(6')-Ih was only found in A. baumannii isolates. The distribution of some of the ARGs was limited to a definite center. CONCLUSION: The overall high-level carriage of ARGs in Acinetobacter species may limited usage of this class of antibacterials as a treatment option.