Molecular analysis and antimicrobial resistance pattern of distinct strains of Pseudomonas aeruginosa isolated from cystic fibrosis patients in Iran.

BACKGROUND AND OBJECTIVES: Colonization of Pseudomonas aeruginosa in Cystic Fibrosis (CF) patients may lead to severe pulmonary disease and death. Different characteristics of P. aeruginosa from these patients were determined in the present study. MATERIALS AND METHODS: Antimicrobial susceptibility and AmpC-overproduction were determined. The ß-lactamase genes were detected by PCR and the oprD gene was sequenced in some of the carbapenem resistance isolates. Distribution of exo genes was determined by PCR. Cytotoxicity of Exo effector proteins was measured using A549 cells. Biofilm production was determined by microtiter plate assay. Random amplified polymorphic DNA (RAPD) -PCR was performed for molecular analysis. RESULTS: Polymyxin B, piperacillin/tazobactam and meropenem were the most active antibiotics and 9.6% of isolates were ampC overproducers. The prevalence of bla VEB, bla OXA, bla VIM, and bla PER genes were as follow: 22.7%, 3.75%, 6.25% and 3.75%, respectively. A high proportion (83.5%) of isolates was able to produce biofilm. The exoT gene was present in all isolates while exoU was present in about 35% of them. RAPD-PCR revealed 49 patterns among 78 tested isolates in which 34 patterns were detected once. CONCLUSION: Biofilm formation ability and relatively high frequency of exoS may contribute to the persistence of bacteria within lungs of CF patients. Some characteristics of isolates recovered from a single patient after several sampling procedures were similar, while others lacked resemblance.

Evaluation of left ventricular function in obese children without hypertension by a tissue Doppler imaging study.

BACKGROUND: The prevalence of obesity is increasing worldwide. Obese children without hypertension are becoming an important health challenge. AIMS: Complications of obesity in adults are well established, but in obese children, cardiac dysfunction has not been reported clinically. SETTINGS AND DESIGN: The present crosssectional study investigates subclinical systolic and diastolic dysfunction using echocardiographic modalities. MATERIALS AND METHODS: Twentyfive youngsters with body mass index (BMI) >30 and 25 healthy children with BMI <25 were assigned into case and control group, respectively. In all participants, complete cardiovascular examination, electrocardiography, and echocardiography were fulfilled. Echocardiography surveys included standard, pulsed wave Doppler (PWD), and tissue Doppler imaging (TDI). STATISTICAL ANALYSIS USED: SPSS software, version 24. RESULTS: The two groups were matched for age and sex. The resting heart rate and blood pressure were markedly higher in the obese group (P = 0.0001) though they were within the normal range in either category. Ejection fraction in the two groups was similar. Left ventricular (LV) mass (P = 0.0001), LV mass index (P = 0.029), left atrialtoaortic diameter ratio (P = 0.0001), and LV enddiastolic diameter (P = 0.008) were significantly greater in the case group, indicating cardiomegaly and subclinical systolic and diastolic dysfunction. Except for the aortic velocity, all PWD variables were considerably lower in the case group, suggesting subclinical diastolic dysfunction. All TDI parameters varied significantly between the two categories. There was a direct correlation between isovolumetric relaxation time and BMI. CONCLUSIONS: Obesity in children without hypertension is associated with subclinical systolic and diastolic cardiac dysfunction. We propose the evaluation of blood pressure as well as myocardial performance using PWD and TDI in all obese children without hypertension, regularly.

Detection and discrimination of two Brucella species by multiplex real-time PCR and high-resolution melt analysis curve from human blood and comparison of results using RFLP.

OBJECTIVES: Rapid and accurate detection of Brucella abortus and Brucella melitensis from clinical samples is so important because antibiotic treatment has major side effects. This study reveals a new method in detection of clinical samples of brucellosis using real-time PCR and high-resolution melt (HRM) curve analysis. MATERIALS AND METHODS: 160 brucellosis suspicious samples with more than 1/80 serum antibody titers were collected and the results were compared with the RFLP method. In order to amplify the sequences for HRM analysis, vdcc, int-hyp and glk and for RFLP, omp2a and omp2b with PstI and Hinf1 restriction endonuclease were used. At last, the accuracy and specificity of the two methods were compared with each other. RESULTS: Out of these 160 samples, multiplex real time PCR showed 108 positive samples (67.5%), including 56% B. melitensis and 44% B. abortus; whereas in PCR-RFLP 52 out of 160 samples were positive, where recognition of two species were accordant with HRM analysis, separation was based on the size of the amplified fragment. Using the designed primers and performing the assay, we confirmed this method to be much faster and have lower cost with more than 99% accuracy compared to methods such as RFLP. CONCLUSION: The present study showed that this technique, which scans gene segments and creates an analysis pattern for detection of clinical samples, is useful and more dominant compared with PCR-RFLP. Thus, this method can be used for brucellosis detection, and clinical and epidemiological research.

Antimicrobial Effect of Imipenem-Functionalized Fe2O3 Nanoparticles on Pseudomonas aeruginosa Producing Metallo ß-lactamases.

BACKGROUND: Resistant strains of Pseudomonas aeruginosa to imipenem was medical treatment problem, especially in burnt units of hospitals. OBJECTIVES: This study was conducted to evaluate the antimicrobial effect of Fe2O3 nanoparticles alone and functionalized with imipenem on P. aeruginosa starins producing metallo ß-lactamases (MBL). MATERIALS AND METHODS: A disk diffusion method was used to isolate a clinical P. aeruginosa producing Metallo ß-lactamases with imipenem resistance. The minimum inhibitory concentration (MIC) of Fe2O3 nanoparticles and imipenem were calculated against the bacteria. The antimicrobial effect of nanoparticles functionalized with the antibiotic was determined. Standard strain of P. aeruginosa ATCC: 27853 was used as control. RESULTS: The clinical sample was resistant to imipenem (up to 28 µg.mL-1). Similarly, MIC of the nanoparticles against the isolate was 160 µg.mL-1. Subsequently, the combination of 16 pg.mL-1 of antibiotic with 80 µg.mL-1 of Fe2O3 nanoparticles were able to inhibit the growth of the isolate. CONCLUSIONS: Fe2O3 nanoparticles functionalized with imipenem can impair antibiotic resistance mechanisms of bacteria as it can make the imipenem resistant the aforementioned bacterium more susceptible to weaker concentrations of antibiotic. It also has its own antibacterial effect in certain concentrations.

Evaluation of antibody response to polysaccharide vaccine and switched memory B cells in pediatric patients with inflammatory bowel disease.

BACKGROUND/AIMS: Inflammatory bowel disease (IBD) is a chronic disease of the gastrointestinal tract, whose etiologies are still unknown. This study was performed to evaluate the humoral immune response in terms of B cell functions in selected IBD patients. METHODS: Eighteen pediatric patients with IBD, including 12 cases of ulcerative colitis (UC) and six with Crohn disease (CD), were enrolled in this study. The pneumococcal vaccine was injected in all patients, and the IgG antibody level to the polysaccharide antigen was measured before and 4 weeks after injection. The B cell switch-recombination process was evaluated. RESULTS: Five patients with IBD (three CD and two UC) had defects in B cell switching, which was significantly higher than in controls (p=0.05). Ten patients had a specific antibody deficiency and exhibited a higher frequency of bacterial infection than the healthy group. The mean increased level of IgG after vaccination was lower in IBD patients (82.9±32.5 µg/mL vs 219.8±59.0 µg/mL; p=0.001). Among the patients who had an insufficient response, no significant difference in the number of switched memory B-cell was observed. CONCLUSIONS: A defect in B lymphocyte switching was observed in pediatric IBD patients, and especially in those patients with CD. Owing to an increased risk of bacterial infections in those patients with antibody production defects, pneumococcal vaccination could be recommended. However, not all patients can benefit from the vaccination, and several may require other prophylactic methods.

Familial congenital hepatic fibrosis: report of a family with three affected children.

Congenital hepatic fibrosis (CHF) is a developmental disorder of the biliary system, characterized by defective remodeling of the ductal plate. Herein a family of three children, from consanguineous parents, with minor thalassemia is presented who suffered from congenital hepatic fibrosis (CHF). Prompt diagnosis and appropriate treatment are necessary to avoid further complications in the affected patients.

Immunohistochemical analysis as a means to predict responsiveness to rituximab treatment.

OBJECTIVE: Anti-CD20-mediated B cell depletion with rituximab is a new and effective therapy for rheumatoid arthritis (RA). Although B cells in peripheral blood (PB) are consistently depleted in all patients, the clinical effects are more heterogeneous, possibly related to differences in the depleting effects of lymphoid or solid tissues. The aim of this study was to investigate B cell depletion in different compartments (PB, bone marrow, and synovium) and determine predictive variables for responsiveness to rituximab therapy. METHODS: Before and 12 weeks after rituximab treatment, samples of PB, bone marrow, and synovium were collected from 25 patients with RA refractory to disease-modifying antirheumatic drugs and tumor necrosis factor-blocking agents. CD19+ and CD20+ B cells in PB and bone marrow were measured by flow cytometric analysis, whereas CD79a+ and cytoplasmic CD20+ B cells in the synovium were stained by immunohistochemistry. The effects of rituximab on serum Ig and autoantibodies were measured by enzyme-linked immunosorbent assay. RESULTS: Rituximab effectively depleted the CD20+ subset of B cells in the PB, bone marrow, and synovium of RA patients. Rituximab significantly reduced autoantibody production (anti-citrullinated protein antibodies [ACPAs] and rheumatoid factor [RF]), in part due to a nonspecific decrease in total Ig production. Importantly, positivity for circulating ACPA IgM, in combination with a high infiltration of CD79a+ B cells in the synovium, but not of CD138+ plasma cells, was a predictor of clinical outcome after rituximab treatment. ACPA IgM titers were independently associated with synovial infiltration of CD20-,CD79a+ B cells, but not with CD138+ plasma cells. CONCLUSION: These data provide novel insights into the mechanisms of CD20-mediated B cell depletion in the lymphoid and solid tissues of RA patients and suggest a pivotal role for ACPA IgM-producing plasmablasts in RA.