Susceptibility of Bacillus subtilis to Zinc Oxide Nanoparticles Treatment.

Aim: With the characteristics such as low toxicity, high total surface, ability to inhibit the growth of pathogenic microorganisms, zinc oxide nanoparticles (ZnO NPs), as one of the metallic nanoparticles, have been chosen as an antibacterial agent to treat various skin infections. The present study was aimed to determine the antibacterial potential of ZnO NPs on Bacillus subtilis, the Gram-positive bacterium that can cause skin and wound infections. Methods: B. subtilis was exposed to 5 to 150 µg/mL of ZnO NPs for 24 h. The parameters employed to evaluate the antimicrobial potential of ZnO NPs were the growth inhibitory effect on B. subtilis, the surface interaction of ZnO NPs on the bacterial cell wall, and also the morphological alterations in B. subtilis induced by ZnO NPs. Results: The results demonstrated a significant (p <0.05) inhibition of ZnO NPs on B. subtilis growth and it was in a dose-dependent manner for all the tested concentrations of ZnO NPs from 5 to 150 µg/mL at 24 h. Fourier transformed infrared (FTIR) spectrum confirmed the involvement of polysaccharides and polypeptides of bacterial cell wall in surface binding of ZnO NPs on bacteria. The scanning electron microscopy (SEM) was used to visualize the morphological changes, B. subtilis illustrated several surface alterations such as distortion of cell membrane, roughening of cell surface, aggregation and bending of cells, as well as, the cell rupture upon interacting with ZnO NPs for 24 h. Conclusion: The results indicated the potential of ZnO NPs to be used as an antibacterial agent against B. subtilis. The findings of the present study might bring insights to incorporate ZnO NPs as an antibacterial agent in the topical applications against the infections caused by B. subtilis.

One stop rectal bleeding clinic: the coventry experience.

Among most patients attending a rectal clinic, rectal bleeding is a common presenting feature. In most patients, the cause is attributed to a benign lesion. In a small percentage, the cause is neoplastic, and for this reason, rectal bleeding merits further study. Left-sided tumors account for the majority of these tumors and are within the reach of a flexible sigmoidoscopy. This study aimed at examining the diagnostic performance of the one stop rectal clinic in Coventry. Between November 2001 and May 2002, 250 consecutive patients were seen in the one stop rectal bleeding clinic of a tertiary referral hospital. Patients were asked of the nature of rectal bleed and altered bowel habits and were examined by digital rectal examination, with a proctoscopy and rigid sigmoidoscopy before either a full colonoscopic examination or flexible sigmoidoscopy with a completion Barium enema. During the study period, colorectal cancer was detected in 4 patients (1.6%), adenomatous polyps in 36 patients (14.4%), and ulcerative colitis in 8 patients (3.2%). In 98 patients (39.2%), no abnormality was present, and in the remaining patients, diverticulosis (n = 60; 24%) and hemorrhoids were present (n = 44; 17.6%).