Loredana Tocalli

In Vitro Antimicrobial Activity of Propolis Dry Extract

Abstract In this study the antibacterial and antifungal properties of propolis, a natural product of bees, have been investigated against different pathogens. Minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) were determined according to NCCLS standards on 320 strains including Staphylococcus aureus, Group A beta-hemolytic streptococci, Streptococcus pneumoniae, Moraxella catarrhalis, Haemophilus influenzae, Klebsiella pneumoniae, Escherichia coli, Proteus mirabilis, Pseudomonas aeruginosa and Candida albicans. Time-kill curves were assessed for susceptible microorganisms, testing 0, 0.5, 1, 2, 4 × MIC for propolis, by counting viable bacteria after 0, 3, 6, 24 hours and viable yeasts after 0, 3, 6, 24 and 48 hours. Propolis showed good antimicrobial activity against most of the isolates, particularly S. pneumoniae, H. influenzae and M. catarrhalis, but not against Enterobacteriaceae. Time-kill curves demonstrated bacteriostatic rather than bactericidal activity of propolis, the latter being evident only at high concentrations.

Effect of Moxifloxacin on Bacterial Pathogenicity Factors in Comparison with Amoxicillin, Clarithromycin and Ceftriaxone

Abstract Moxifloxacin is a recent fluoroquinolone with an antibacterial spectrum encompassing both aerobic Gram-negative and Gram-positive strains, as well as anaerobic bacteria. In this study the activity of moxifloxacin against Streptococcus pneumoniae, Staphylococcus aureus, Moraxella catarrhalis, Haemophilus influenzae, Escherichia coli, Proteus mirabilis and Pseudomonas aeruginosa, and effects of subinhibitory concentrations on bacterial morphology and adhesion properties were compared with those of amoxicillin, clarithromycin and ceftriaxone. The in vitro activity of moxifloxacin against Gram-positive and Gram-negative pathogens was equal to or better than that of comparators. Subinhibitory concentrations of moxifloxacin significantly affected bacterial morphology of S. pneumoniae, M. catarrhalis, H. influenzae and P. aeruginosa, leading to formation of spherical forms and filaments. Moreover, bacterial adhesion to buccal cells and fibroblasts was reduced after treatment with 1/4 and 1/8 X MIC of moxifloxacin. In conclusion, subinhibitory concentrations of moxifloxacin remarkably interfere with some bacterial pathogenic factors, thereby contributing to its antimicrobial activity.

Salmonellosis diagnosed by the laboratory of the ‘L. Sacco’ hospital of Milan (Italy) in patients with HIV disease

We reviewed the cases of typhoid fever (3 cases) and non-typhoid salmonellosis (62 cases) diagnosed from 1987 to 1989 in the Laboratory of Clinical Chemistry and Microbiology of the ‘L.Sacco’ Hospital, Milan.Two cases of typhoid fever and 24 cases of non-typhoid salmonellosis occurred in patients without clinical symptoms of HIV infection. One case of typhoid fever and 38 cases of non-typhoid salmonellosis occurred in patients with clinical symptoms of HIV infection.In AIDS patients living in the Milan province the annual incidence of non-typhoid salmonellosis was estimated to be 100-fold greater than that observed in the general population.In patients with non-typhoid sahnonellosis, bacteremias was found only in subjects with HIV disease (P=0.0009). The frequency of bacteremia was higher in patients with AIDS than in patients with other manifestations of HIV disease (P=0.0356).Finally, a significant difference between patients with and without HIV disease was found with regard to Salmonella serotypes distribution (P=0.0196).