barzelighi

The aim of this study was to evaluate the antibacterial and antibiofilm activity of recombinant Azurin from Pseudomonas aeruginosa against different bacterial species. The azurin gene was cloned in the pET21a vector. The pET21a-azurin construct was transformed into Escherichia coli BL21. The recombinant Azurin was expressed and purified using affinity chromatography and confirmed by Western blotting. The cytotoxicity of rAzurin was assessed on peripheral blood mononuclear cells. Antibacterial and antibiofilm activity of rAzurin with different concentrations were determined by micro-broth dilution and crystal violet methods, respectively. The effect of rAzurin on bacterial species was statistically analyzed by t- test and spearman correlation. The identity of purified protein was confirmed by blotting and distinguished as a 14 kDa band on 15% SDS-PAGE. The IC50 of rAzurin on Peripheral Blood Mononuclear Cell (PBMC) was determined as 377.91±0.5 µg/mL in 24 h. Vibrio cholerae and Campilobacter jejuni displayed the most sensitivity to rAzurin (27.5 and 55 μg/mL, respectively) and the highest resistance (220 μg/mL) was displayed by P. aeruginosa and E. coli. The MIC for other species was 110 μg/mL. The Minimum Biofilm Inhibition Concentration (MBIC) was determined as 220 μg/mL for Salmonella enterica and V. cholerae, 300 μg/mL for Shigella sonnei, Shigella flexneri and P. aeruginosa and 440 μg/mL for the other species. The antimicrobial effect of rAzurin on bacterial species were significant (p value<0.05) and correlation coefficient was negative. The rAzurin appears to be an appropriate choice and a new strategy for prevention of bacterial infection. It inhibits bacterial growth and biofilm formation and candidates as antimicrobial peptides.

Helicobacter pylori، which is associated with many upper gastrointestinal diseases، is found in half of the population of the world. Several special stains and immunohistochemistry stain for H. pylori are available. The need for and usefulness of immunohistochemical (IHC) technique has been debated for years. Toluidine blue is a simple stain for microbiological studies and is easily available in laboratories. Therefore، this study was conducted to compare hematoxylin and eosin (H&E)، Giemsa and toluidine blue staining with immunehistochemistry for detection of H. pylori in patients with gastritis and also to correlate the results of these staining methods with pathological grading.

We reviewed 54 consecutive gastric biopsy specimens stained by H&E and Giemsa as well as by toluidine blue and immunohistochemistry stains for H. pylori.

H. pylori was positively identified by IHC in 43 (79. 63%) patients، while positive samples were found in 18 (33. 33%)، 24 (44. 44%) and 33 (61. 11%) patients using H&E، Giemsa and toluidine blue staining methods. Our results showed that classical histological staining methods are not sensitive enough to identify low numbers or coccoid forms of organism، while toluidine blue and immunohistochemistry play an important role in detection of H. pylori infection.

Toluidine blue has been proved to be much more reliable than H&E and Giemsa in detection of H. pylori. In addition، in post treatment biopsies and in biopsies with unexplained chronic active gastritis without histological evidence of H. pylori should have immunohistochemistry done to detect possible low density or coccoid form of organisms.

Multi-drug resistant strains of Acinetobacter spp. have created therapeutic problems worldwide. The objective of this study was to detect integrons in Acinetobacter spp. isolates from Ventilator-Asso­ciated Pneu­monia patients using PCR method. A total 51 Bronchoalveolar lavage samples were obtained from pa­tients in ICU and examined for Acinetobacter spp. infection by bio­chemi­cal and PCR methods using blaOXA51-like primers. An­timi­crobial suscep­tibility testing was performed using disk diffusion and MIC me­thods. Among 51 patients with VAP (62.7% males, 35.2% females, mean age 53 year), 50 (98%) were positive, with a high prevalence of gram-nega­tive bacteria, mainly Acinetobacter spp. (70%), from which A. baumani was detected in 34 (68%) and A. lwoffii in 1 (2%) of iso­lates. More than 90% of isolates were resistant to imipenem, pipera­cil­lin+tazobactam, third genera­tion cephalosporins and gentamicin, while the most effective antibiotic was colistin (100%). The correla­tion coeffi­cient between disk diffusion and MIC was 0.808 (p = 0.001). Three Aci­netobacter isolates (8%) harbored integrase I gene but none of isolates contained Class II or III integrons. The results showed that colistin was an effective antibi­otic and can be used for treatment of patients in ICU. Due to the high number of MDR isolates lacking Integrons it can be concluded that although class I in­tegrons are important among clinical isolates of A. baumannii, they have no significant role in dissemination of antibiotic resistance genes in Rasoul Akram Hospital in Tehran, Iran. The pres­ence of IntI in A. lwoffii may be related to transfer of integron to A. baumannii which can be con­sidered as an important threat for hospi­talized patients.