In vitro activities of cellulase and ceftazidime, alone and in combination against Pseudomonas aeruginosa biofilms.

BACKGROUND: Biofilms are a main pathogenicity feature of Pseudomonas aeruginosa and has a significant role in antibiotic resistance and persistent infections in humans. We investigated the in vitro activities of antibiotic ceftazidime and enzyme cellulase, either alone or in combination against biofilms of P. aeruginosa. RESULTS: Both ceftazidime and cellulase significantly decreased biofilm formation in all strains in a dose-dependent manner. Combination of enzyme at concentrations of 1.25, 2.5, 5, and 10 U/mL tested with 1/16× MIC of antibiotic led to a significant reduction in biofilm biomass. Cellulase showed a significant detachment effect on biofilms at three concentrations of 10 U/mL, 5 U/mL, and 2.5 U/mL. The MIC, MBC, and MBEC values of ceftazidime were 2 to 4 µg/mL, 4 to 8 µg/mL, and 2048 to 8192 µg/mL. When combined with cellulase, the MBECs of antibiotic showed a significant decrease from 32- to 128-fold. CONCLUSIONS: Combination of the ceftazidime and the cellulase had significant anti-biofilm effects, including inhibition of biofilm formation and biofilm eradication in P. aeruginosa. These data suggest that glycoside hydrolase therapy as a novel strategy has the potential to enhance the efficacy of antibiotics and helps to resolve biofilm-associated wound infections caused by this pathogen.

Evaluation of antimicrobial resistance, biofilm forming potential, and the presence of biofilm-related genes among clinical isolates of Pseudomonas aeruginosa.

OBJECTIVES: Pseudomonas aeruginosa is known as a leading cause of nosocomial infections worldwide. Antimicrobial resistance and biofilm production, as two main virulence factors of P. aeruginosa, are responsible for the persistence of prolonged infections. In this study, antimicrobial susceptibility pattern and phenotypic and genotypic characteristics of biofilm of P. aeruginosa were investigated. RESULTS: A total of 80 clinical P. aeruginosa isolates were obtained. Isolates showed resistance to all antibiotics with a rate from 12.5% (n = 10) against amikacin and piperacillin/tazobactam to 23.75% (n = 19) to levofloxacin. Multidrug-resistant P. aeruginosa accounted for 20% (n = 16). 83.75% (n = 67) of isolates showed biofilm phenotype. All three biofilm-related genes were found simultaneously in 87.5% (n = 70) of P. aeruginosa and 13.5% (n = 10) of the isolates had none of the genes tested. From the results of the present study, combination therapy including an anti-pseudomonal beta-lactam (piperacillin/tazobactam or ceftazidime) and an aminoglycoside or carbapenems (imipenem, meropenem) with fluoroquinolones in conjunction with an aminoglycoside can be used against Pseudomonas infections. However, reasonable antimicrobial use and high standards of infection prevention and control are essential to prevent further development of antimicrobial resistance. Combination strategies based on the proper anti-pseudomonal antibiotics along with anti-biofilm agents can also be selected to eradicate biofilm-associated infections.

Three common CARD15 mutations are not responsible for the pathogenesis of Crohn's disease in Iranians.

BACKGROUND/AIMS: Crohn's disease frequency has increased in recent years in Iran. Genetic and environmental factors predispose people to this disease. Mutation in Caspase Recruitment Domain 15 (CARD15) gene is the most well known genetic predisposing factor to this disease. Frequency of three common CARD15 mutations has been studied in different ethnic groups. We aimed to study the frequency of these mutations in Iranian patients affected with Crohn's Disease. METHODOLOGY: One hundred fifteen proved cases of Crohn Disease and 115 age and sex matched normal controls were recruited in this study. Lf1007fs, R702W and G908R mutations were studied by Polymerase Chain Reaction-Restriction Fragment Length Polymorphims (PCR-RFLP) followed by sequencing the positive cases. RESULTS: Lf1007fs and G908R mutations were not found in either patients or age-sex matched controls. Just in two patients, R702W mutation was proved by Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) and sequencing. None of these patients had illeal or fibrostenotic type of disease while 14.7% of total patients had stricturing type of disease. No complication was seen in these two patients while 50.4% of patients had acquired complications during the course of disease. CONCLUSION: The three mutations described are not responsible for the pathogenesis of Crohn's Disease in Iranians. The results are in accordance with other Asian nations' studies on IBD Patients.

Molecular analysis of factor IX gene in an Iranian female with severe hemophilia B.

Hemophilia B, a recessive X-linked coagulopathy, is rare in females, and only a few cases have been reported so far. In this report, we describe a 9-year-old female, offspring of a consanguineous marriage, with a clinically severe course of hemophilia B and a normal 46,XX karyotype. Polymerase chain reaction and conformation sensitive gel electrophoresis techniques have been applied to the important regions of the factor IX gene,and an abnormal conformation sensitive gel electrophoresis profile was identified in exon 5 of the gene. After sequencing, the mutation was found to be C17761T (R116X) in homozygous form. Then, polymerase chain reaction-restriction fragment length polymorphism using the EcoRV restriction enzyme was applied for confirmation of the homozygous mutation in the proband and for carrier testing in the relatives. In addition, haplotype analysis was informative at the HhaI polymorphic site for the female patient.