Anti-HBc screening in Egyptian blood donors reduces the risk of hepatitis B virus transmission.

Occult hepatitis B virus (HBV) in blood donors is considered as a potential risk for transmission of HBV infection. The aim of this study was to determine the prevalence of anti-hepatitis B core antibody (anti-HBC) positivity in Egyptian blood donations as well as to estimate the frequency of HBV-DNA in anti-HBc-positive donations. The study included 760 Egyptian healthy blood donors, representing 26 different Egyptian governorates screened according to routine practice for the presence of hepatitis B surface antigen (HBsAg), hepatitis C virus (HCV) antibodies (Abs), HIV-1/2 Abs and Treponema Abs. The accepted blood units for donation were tested for the presence of total anti-HBc Abs by two tests. Positive units for anti-HBc were further tested for HBV-DNA by polymerase chain reaction. According to routine screening, a total of 48/760 units (6.3%) were rejected [38 (5%) HCV-Ab-positive units, 9 (1.18%) HbsAg-positive units and 1 (0.13%) Treponema-Ab-positive unit]. Among the accepted blood units for donation, prevalence of anti-HBc was 78/712 units (10.96%). HBV-DNA was detected in 9/78 (11.54%) of the anti-HBc-positive units, and thus, occult HBV infection was detected in 9/712 (1.26%) of the accepted blood donations. Implementing anti-HBc test to the routine assay for the forthcoming two decades would certainly eliminate possible HBV-infected units. Rejection of these units will be beneficial to decrease the risk of HBV transmission with its potential consequences particularly in immunocompromised recipients.

In-vitro activity of commonly used antifungal agents in the presence of rifampin, polymyxin B and norfloxacin against Candida albicans.

This study assessed the in-vitro antifungal activity against Candida albicans of amphotericin B, ketoconazole and miconazole, each in the presence of rifampin, polymyxin B and norfloxacin. Evaluation of drug interactions was estimated by the checkerboard pattern broth dilution method and by time-kill studies. Rifampin reduced the activity of the three antifungal agents used, with the reduction being more pronounced with amphotericin B. Synergy was observed when polymyxin B was combined with any of the antifungal agents used. The addition of norfloxacin resulted in minimal, if any, change in the activity.

Macrolides induced suppression of virulence factors produced by Staphylococcus aureus.

The effect of sub-MICs of azithromycin, clarithromycin and roxithromycin, as compared to erythromycin, on the production of coagulase, beta-hemolysin, lecithinase and deoxyribonuclease by Staphylococcus aureus was studied. All new macrolides completely inhibited coagulase and beta-hemolysin production and partially inhibited lecithinase and deoxyribonuclease. Such inhibition is not related either to growth inhibition or to inhibition of enzyme activity. Erythromycin, on the other hand, had no effect on coagulase or beta-hemolysin production but slightly suppressed the production of lecithinase and deoxyribonuclease. This inhibitory effect might have clinical significance if it was found to occur in vivo.

Correlation between the in vivo and in vitro antimicrobial properties of commercially available mouthwash preparations.

The effectiveness of six commercially available mouthwashes against common buccal organisms was studied. The minimum inhibitory concentrations (MIC) for two of the studied mouthwashes (Corsodyl and Oraldene) against buccal organisms were determined in Todd Hewitt medium with or without 5% serum. The concentration of the active substance in these two mouthwashes was in excess of the corresponding MIC. When the medium was supplemented with serum, lower MIC values were observed. Kill-time determinations, used at half the concentration of the normal preparation, revealed a rapid lethal effect for all tested mouthwashes. The slowest lethal effect was observed with Fluocaril mouthwash. When mouthwashes were tested in volunteers, an immediate significant fall in salivary bacterial counts was produced by all except Fluocaril. With the latter mouthwash the decrease was significant 2-30 minutes after rinsing. The bacterial levels returned to pre-rinse levels after 30 minutes for Listerine, after 90 minutes for both Oraldene and Mint and after 180 minutes for Corsodyl, Fluocaril and Sansilla mouthwashes. The results indicate that there is a good correlation between in vivo efficacy and in vitro determination of all mouthwash preparations.

The establishment and maintenance of a small culture collection in Egypt with a computerized database.

A major constraint for expanding biotechnology in developing countries is the tack of appropriate microbial strains and microbial genetic resources. The recently established Microbial Strain Data Network (MSDN) offers the opportunity of, at least partially, llfting these constraints, since even a small institutional culture collection with limited to moderate facilities can act as an active two-way node in the network. We describe the establlshment of a nucleus for culture collection in the biotechnology laboratory, selecting methodologies as compatible as possible with those of the Cairo MIRCEN, and in assembling a database on the collected strains using a format that lends itself to participation in the MSDN.