Antibiotic-resistant Staphylococcus aureus strains of swine origin: molecular typing and susceptibility to oregano (Origanum vulgare L.) essential oil and maqui (Aristotelia chilensis (Molina) Stuntz) extract.

AIM: The molecular typing and the susceptibility of Staphylococcus aureus strains of swine origin to antibiotics, oregano (Origanum vulgare L.) essential oil (EO) and Chilean blackberry maqui (Aristotelia chilensis (Molina) Stuntz) extract were determined. METHODS AND RESULTS: Twenty S. aureus strains of swine origin were subjected to molecular typing, of which six strains were selected for antimicrobial susceptibility testing. The epsilon test (Etest) was used to determine the antibiotic susceptibility. The susceptibility to natural antimicrobials (NAs): oregano EO, maqui extract, thymol (Thy) and carvacrol (Carv), was carried out using the disk diffusion method. The S. aureus strains were genetically diverse. All strains were resistant to at least one class of antibiotic, and two strains were multidrug-resistant. The minimum inhibitory concentration of oregano EO, Thy and Carv was 0·01-0·04%. Maqui extract did not show antistaphylococcal activity. CONCLUSIONS: Natural antimicrobials extracted from oregano have an inhibitory activity against S. aureus strains from swine origin, with no effect using maqui extract. SIGNIFICANCE AND IMPACT OF THE STUDY: This study provides information about the characteristics of S. aureus strains of swine origin, and about the potential use of NAs from oregano to enhance the control of antibiotic-resistant S. aureus strains in the pork supply chain.

Improving recruitment and retention for an online randomized controlled trial: experience from the Youthnet study.

The objective of the study was to present recruitment and retention findings for an Internet based HIV prevention trial evaluated using a randomized controlled design among 15-25-year-olds accessing a website on the Internet. We used a combination of automated electronic and personalized approaches to increase and diversify recruitment, verify participant eligibility and increase retention. We posted 3.5 million banner advertisements, 9354 individuals clicked on the advertisement, 8950 completed an eligibility screener and 3298 a baseline survey; we flagged 675 of these as suspicious and enrolled 2623 individuals. Of these, 2082 (79%) completed a follow-up at one-month and 1398 (53%) completed a two-month follow-up. This retention rate is the highest we have seen for an Internet-based HIV-prevention trial. Our procedures can be replicated in other trials. We stress the importance of using a combination of automated and personalized techniques to increase enrollment, verify eligibility and promote retention.

Lymphocyte subsets alteration in patients with argentine hemorrhagic fever.

Peripheral blood lymphocyte subpopulations were studied in 15 patients with Argentine Hemorrhagic Fever (AHF), during the acute period of the disease and in early convalescence. Anti-human Ig antibodies were used to identify B cells and monoclonal antibodies to assess T4 and T8 subsets. During the acute period of the disease, significant alterations were found in B, T4, and T8 lymphocytes (P less than .001), as well as in T4/T8 ratios (P less than .001). These abnormalities disappeared in early convalescence, around 30 days after the clinical onset. Diminished numbers of T4 lymphocytes are interpreted as relevant to the immunodepression that characterizes the acute phase of AHF.

Tolerance and antiviral effect of ribavirin in patients with Argentine hemorrhagic fever.

Tolerance and antiviral effect of ribavirin was studied in 6 patients with Argentine hemorrhagic fever (AHF) of more than 8 days of evolution. Administration of ribavirin resulted in a neutralization of viremia and a drop of endogenous interferon titers. The average time of death was delayed. A reversible anemia was the only adverse effect observed. From these results, we conclude that ribavirin has an antiviral effect in advanced cases of AHF, and that anemia, the only secondary reaction observed, can be easily managed. The possible beneficial effect of ribavirin during the initial days of AHF is discussed.