Biomedical subjects

P Messi

Publications and source records attributed to P Messi.

5 recordsLinked to original sources

PubMed1991

Streptococcus mutans: classification in bacteriocin-types.

A sample of S. mutans bacteriocins was studied to obtain a useful outline of strain typing since their synthesis has proved stable and not under plasmidial control. The inhibiting effectiveness against 9 oral streptococci and the sensitivity of mutacins produced by 49 S. mutans strains to heat, chloroform and proteasic activity were evaluated. On the basis of our results the producing strains are classified into five different types. We examine the possibility of obtaining a useful typing with bacteriocins and we discuss the choice of the most suitable number of indicators to arrange the strains in a limited cluster number for epidemiological purpose, or to classify freshly isolated S. mutans strains into bacteriocin-types.

Bacterial Typing Techniques↗

PubMed1987

In vitro antibacterial activity of enoxacin, a new pyridonecarboxylic acid.

The antibacterial activity of enoxacin was determined against 1015 strains of Gram-positive and Gram-negative bacteria, mainly freshly isolated from clinical specimens. The minimum inhibitory concentrations (MIC 50-75-90) were determined in comparison to three commonly used antibiotics: ampicillin, cefotaxime and gentamicin. Enoxacin has shown a broad spectrum of action and antibacterial activity in general higher that than of three currently available antibiotics. The antibacterial activity seems similar to that of other quinolones of second generation.

Ampicillin↗

PubMed1987

Production of bacteriocin-like substances by human oral streptococci.

A sample of human streptococci (mainly Streptococcus mutans species) from dental plaques was examined in order to evaluate the production frequency and activity spectrum of bacteriocin-like substances (mutacins). 89% of the 55 Streptococcus mutans strains produced substances with a wide spectrum of antibacterial activity. The bacteriocins produced showed a marked inhibitory activity against Gram-positive bacteria. Among the Gram-negative species tested, only Neisseria sicca was inhibited by 25% of Streptococcus mutans strains. Also, 16 strains belonging to oral streptococci other than Streptococcus mutans, were examined for their inhibitory capacity against the same indicator. The authors stress the importance of mutacins production in oral ecology and Streptococcus mutans pathogenicity.

Bacteriocins↗

PubMedDate not supplied

Chlamydia trachomatis infections in asymptomatic women. Results of a study employing different staining techniques.

A total of 300 cervical smears randomly collected from asymptomatic women in a mass-screening program for the detection of cervical carcinoma was investigated for Chlamydia trachomatis infection by the use of Papanicolaou and immunofluorescence staining. Features of chlamydial infection detected in 18 cases by Papanicolaou-stained smears were confirmed in 11 cases with immunofluorescence; not a single case that was negative in the Papanicolaou-stained smears was positive by immunofluorescence. The presence of Chlamydia in the Papanicolaou-stained smears in ten cases, including two cases that were negative by immunofluorescence, was also proven by either immunoperoxidase staining or in situ hybridization. On the other hand, either immunoperoxidase or in situ hybridization gave false-negative results in two of the ten cases. Therefore, the combined use of different techniques demonstrated that false-negative results occurred with all techniques, except with Papanicolaou-stained smears, whose sensitivity is apparently the highest.

Chlamydia Infections↗

PubMedDate not supplied

[Presence of bacteria belonging to the genus Yersinia in surface and ground water].

Yersinia strains in surface waters and ground waters. After reviewing national and international writing regarding the prevalence of yersiniae in surface waters and ground waters, the Authors report data about a research carried out in the province of Modena (Italy). Over a period of 16 months (february 1986-may 1987) 89 water samples were examined (55 samples collected from rivers and streams and 34 from wells). During every sampling session two samples were collected; one was taken in a sterile bottle (1000 cm3), one by means of the Moore tampon, allowed to float in the stream for 48 h. Yersinia strains were isolated from 37% of the water samples; 33 samples gave a positive result. Forty one strains were isolated on the whole; filtration method by Millipore membrane appeared the most suitable technique in order to obtain a good recovery rate. Y. enterocolitica appeared the most represented species (43.8%), followed by Y. intermedia (21.9%) and Y. fredericksenii (17.1%). Five atypical strains were isolated, while no strain belonging to the species Y. kristensenii has been evidenced. No relevant difference in Yersinia presence appeared between surface waters and ground waters. No human pathogenic strain has been evidenced and all the isolates appeared belonging to environmental biogroups, serogroups and phage-types.

Italy↗