Biomedical subjects
Publications and source records attributed to A Lavitola.
ABAC-ABACTOR II system has been compared with two conventional methods (Enterotube II and MS-2) for the identification of Enterobacteriaceae. Our findings demonstrate the validity and the reproducibility of the identification obtained with this system.
Using a simple and rapid microassay, we tested 100 strains of Neisseria gonorrhoeae isolated from 81 patients (41 men and 40 women) for their sensitivity to killing by normal human serum (NHS). The reproducibility of the test was good when the bactericidal end points were taken as the dilution of fresh NHS that killed more than 95% of the test organisms. The bactericidal end points of strains isolated either from different anatomical sites or from sexual partners correlated well with the levels of sensitivity to serum of corresponding isolates, as well as with auxotypes. When the strains were not highly resistant to killing by NHS, this marker gave a precise definition of each strain and permitted the differentiation of isolates belonging to common auxotypes.
A previously described 70-Kd antigen present in all Neisseria gonorrhoeae strains tested and in most Neisseria species was characterized as a mercaptoethanol-and heat-stable protein. Using mouse polyclonal antisera specifically directed against this antigen, it was shown that it is a surface-exposed structure. The 70-Kd antigen was recovered from all gonococcal strains isolated from different anatomic sites in male and female partners, thus demonstrating its antigenic stability after in vivo transmission in humans.
We have isolated from a genomic library of the pathogenic Neisseriae gonorrhoeae T2 strain, a gene encoding a putative protein of 268 amino acids which exhibited significant similarity to the hisJ and argT gene products of Salmonella typhimurium and Escherichia coli, periplasmic proteins deputed to amino acid transport within the cell. The gene is transcribed as a monocistronic mRNA species of about 960 nucleotides flanked by regulatory elements for initiation and termination of transcription that are efficiently recognized in an E. coli host.
A surface antigen of 70 Kd, common to most Neisseria species, was previously described. This antigen is expressed and immunogenic in vivo in humans since 70-Kd-specific antibodies were detected in 22/26 patients with meningococcal meningitis and 12/17 healthy meningococcal carriers. Sera from convalescent patients and from carriers blocked the binding between mouse 70-Kd-specific serum and a strain of N. gonorrhoeae. The correspondence between inhibition-ELISA, using whole gonococci as solid phase, and detection of anti-70-Kd antibodies by Western blotting confirmed the specificity of the mouse serum. Non-pathogenic Neisseria species although possessing the 70-Kd structure elicited less frequently an antibody response in children. The immunogenicity of the 70-Kd antigen in humans supports its potential use as a vaccine component.
The in vitro activity of enoxacin, a new quinolone derivative, was tested against 2180 bacterial strains, recently clinically isolated, by measuring the minimum inhibitory concentrations. Comparisons were made with other drugs (flumequine, oxolinic acid, pipemidic acid) widely utilized for the treatment of urinary tract infections. Enoxacin showed the highest activity against all the tested strains, with a geometrical mean of MICs (MG) of 0.39 micrograms/ml and a MIC 50 and MIC 90 of 0.25 and 4 micrograms/ml, respectively.
A comparative evaluation between IIF and EIA methods for serological diagnosis of Toxoplasmosis has been carried out testing 920 serum samples. Both methods have been considered as equally valuable and accurate. The Authors prefer to utilize the IIF for screening purposes and EIA, which has been more sensitive at intermediate range of values, for the follow-up of the different immunological responses against Toxoplasma gondii.