Microbiologica最新文献

We propose a rapid two-step PCR to amplify a 767-bp sequence present in the gene coding for the 65-kD antigen of mycobacteria. The high G+C content (80%) permitted annealing to occur at 70 degrees C, enhancing the specificity. The amplified fragment contains a restriction site for differentiation between M. tuberculosis, M. bovis/BCG, and M. avium. Complete diagnosis can be achieved in less than four hours without labelled probe or nucleic acid transfer.

Hypocholesterolemic effect was shown in axenic, mono, bicolonized and conventional mice: the effect was different depending on probiotic properties of intestinal microorganisms. Contamination by Enterococcus faecium CX determined the highest effect: haematic cholesterol level decrease was 16.9% in females and 7.8% in males. In mice contaminated by Lactobacillus acidophilus N5 the decrease of haematic cholesterol levels was less and not relevant in mice contaminated by conventional microflora. Enterococcus faecium CX and Lactobacillus acidophilus N5 strains were able to grow in presence of bile salts, to colonize intestinal tract, to survive at gastric conditions and to assimilate cholesterol (E. faecium more than L. acidophilus). The authors consider the possibility to associate probiotic strains with these characteristics for the health of consumers.

421 strains of Pseudomonas aeruginosa were isolated from patients admitted to intensive care units and tested with automated systems for sensitivity to 21 antimicrobial agents. Data were collected in a database for evaluation and monitoring of resistance development. Results showed that assisted monitoring of antimicrobial resistance gives continuously updated information, with particular attention to the different local therapeutical schedules. It is therefore advisable that clinicians constantly exchange information with the microbiology laboratory through a hospital information system in which data from different laboratories are pooled in real time.

Mice lethality bioassay revealed that out of 102 proteolytic cell-free cultures of Pseudomonas aeruginosa only 17 (15%) were lethal with values of 19-48 LD50/ml. Antitoxin A antiserum neutralized the lethality providing evidence that the main lethal compound in the cell free cultures was exotoxin A. The neutralization also ruled out the lethal contribution of protease, elastase and phospholipase c. The presence of exotoxin A in a proteolytic environment may indicate less efficient proteolytic action at the stage of toxin production.

Eleven strains of Mobiluncus spp. were isolated from 35 vaginal secretions of patients with bacterial vaginosis (6 Mobiluncus curtisii and 5 Mobiluncus mulieris).

Erythema migrans was described in Italy only in 1971 although Italian dermatologists were familiar with it a long time before. In 1983, the first case of Lyme borreliosis with multisystem involvement was identified. The endemic areas in Italy are the Ligurian coast, the province of Friuli Venezia Giulia, and the region surrounding the town of Bologna. In Liguria, the incidence of Lyme disease is about 17/100,000 inhabitants per year. Serosurveys of the general population and of sentinel animals were useless in determining the diffusion of Lyme borreliosis whereas evaluation of people at risk of tick bites and patients with suggestive signs or symptoms was more effective. Among the clinical manifestations of Lyme borreliosis, cutaneous involvement is four times more frequent than neuroborreliosis and arthritis is less frequent in Italy than in the USA.

The antiviral activity of methisoprinol was investigated under different conditions using a strain of hepatitis A virus (HAV), that shows a strong cytopathic effect on the Frp/3 cell line 7-9 days post-infection. Treatment of Frp/3 at a dose range of 125-1200 micrograms/ml had no toxic effect and showed a dose dependent inhibition of the HAV replication cycle. At the methisoprinol dose of 500 micrograms/ml the cytopathic effect was completely abolished and HAV antigen production reduced by 50% as measured by indirect immunofluorescence (IIF) and commercial enzyme-linked assay (ELISA). The virus yield was virtually abolished at the highest dose employed (1000 micrograms/ml).

The role of phospholipids in BK virus infection and haemagglutination was studied by competition binding experiments and by treatment of susceptible cells with phospholipases. Phospholipids extracted from Vero cells and some commercial phospholipids showed an inhibiting activity on both BK virus infectivity and haemagglutination. The treatment of Vero cells with phospholipases affected the binding of BK virus, but the addition of phospholipids to enzyme-treated cells restored their susceptibility to both viral infectivity and haemagglutination.

In the ambit of the B. subtilis genoma sequencing and mapping project, we have set up an electroporation method to transfect E. coli cells with lambda DNA. This methodology presents features that make it preferable to traditional in vitro packaging for some purposes. Here we will illustrate the experimental procedure and the possible applications.

Eight 40-day pregnant gilts, previously treated with an adjuvanted-inactivated viral preparation (AIVP) obtained with a field strain of porcine parvovirus (PPV) together with 4 pregnant untreated controls, were subjected to challenge infection with a virulent strain of PPV at the 40th day of gestation. After challenge, all controls became febrile for 2 to 8 days, whereas only one gilt among those which had been treated with the AIVP experienced fever which lasted 4 days. Virus was consistently recovered from fecal swabs obtained from the controls and only sporadically from feces of AIVP-treated gilts. When the gilts were killed 53 days after challenge infection, no macroscopic lesions were found in any of the gilts in either groups, but fetal death was observed in the two groups of animals. However, the rate of dead fetuses was much higher among the control (70.5%) than among those from the AIVP-treated gilts (10.1%). Virus was recovered from 23 of the 24 dead fetuses in the control group and only from 3 among the 8 dead fetuses which were reported for the AIVP-treated gilts.