Biomedical subjects

A M Israil

Publications and source records attributed to A M Israil.

13 recordsLinked to original sources

PubMed1996

Isolation of a new epidermin variant from two strains of Staphylococcus epidermidis--frequency of lantibiotic production in coagulase-negative staphylococci.

A novel lantibiotic identified during the screening of 187 coagulase-negative staphylococci, has been structurally characterised. (Val1, Leu6)-epidermin was purified from culture supernatants of two Staphylococcus epidermidis strains, BN-V1 and BN-V301 following successive separation by adsorption, cation exchange and C18 reversed-phase chromatography. Separation of the purified peptides by SDS-polyacrylamide gel electrophoresis suggested a molecular mass of ca. 2000 Da and electrospray mass spectrometry subsequently demonstrated that both peptides had a mass of 2151 Da; a mass which is different from that of all previously described antimicrobial peptides. Amino acid analysis showed that both peptides contained lanthionine and were very similar to epidermin, while automated N-terminal sequencing by Edman degradation confirmed the identity of the two peptides as a natural variant of the antimicrobial lantibiotic epidermin, and demonstrated the conservative amino acid exchanges in positions one and six.

Alanine↗

PubMed1987

The development and application of a bacteriocinogenotyping scheme for Vibrio cholerae non-group O-1 strains.

423 Vibrio cholerae non-group O-1 strains were tested for vibriocin production using a homologous set of 7 indicator strains. Using this scheme, 334 (79.4%) strains proved to be typable. The strains isolated from 7 different geographical areas of Romania exhibited 16 different patterns of vibriocin production. The presence of a predominant pattern per year and per region was revealed.

Animals↗

PubMed1983

Studies on bacteriocin production by NAG-strains of Vibrio cholerae as a possible epidemiological marker.

201 "non-agglutinable" - i.e. serogroup O:1-negative - Vibrio cholerae strains were tested for bacteriocin production using 14 of the Abbott-shannon standard set of colicin-sensitive strains as indicators. 41.2% of the strains proved to be bacteriocin producers. 29 out of 67 (43%) vibriocin-positive strains originating from one large geographical region gave the same reaction pattern with the applied indicator strains. The possible significance of these vibriocins for epidemiological studies is discussed, and the necessity for further investigations prior to routine bacteriocin typing of O:1-negative V. cholerae strains is pointed out.

Animals↗

PubMed1981

The significance of bacteriocin typing of Klebsiella strans.

Out of three different methods used for bacteriocin sensitivity typing of Klebsiella strains, the "scarpe and streak" method was the most appropriate tool for its routine use in epidemiologic studies. The method is quite simple, reliable and does not imply any special requirements. Out of 533 Klebsiella strains tested by our set of seven bacteriocins 453 (85%) strains proved to be typable and 100 (15%) nontypable. The number of strains typable by bacteriocins was higher than of those typable by phages. In 14 of 19 outbreaks, the predominance of 1-2 distinct patterns of bacteriocin sensitivity was observed. Two large geographical areas have been delineated by two predominant distinct bacteriocin types of Klebsiella strains, each being observed in a high number of outbreaks as well as in sporadic cases belonging to the same area. Although it was not possible to establish any clear correlation between the pattern of bacteriocin sensitivity and the lysotype or serotype of the strains, The present findings offer strong reason to allow recommendation of the bacteriocin sensitivity pattern as a marker of high epidemiologic significance in monitoring Klebsiella cross-infections. Medical and auxiliary workers could play the role of reservoir to Klebsiella strains and for this reason the hospital personnel has to follow carefully strict procedures for ensuring a valid protection of patients especially when coming into direct contact with neonates, infants and debilitated patients.

Bacteriocins↗

PubMed1980

Studies on bacteriocin production and sensitivity of Klebiella strains using the Abbott-Shannon sets of standard strains.

In the present study, the bacteriocin production of 308 Klebsiella strains and bacteriocin sensitivity of 131 Klebsiella strains were investigated by help of the two Abbott and Shannon sets of standard strains for colicin typing of Shigella sonnei. 63% of Klebsiella strains were found to be bacteriocin producers. Although a certain bacteriocin production pattern was predominant in 8 of 11 outbreaks studied it could not be demonstrated that this marker could confer any epidemiological relationship among the strains of the same focus. 70% of Klebsiella strains were colicin sensitive. Three different patterns of colicin sensitivity were described and one of them was predominant (in 89% of cases). Three different patterns of colicin sensitivity were described and one of them was predominant (in 89% of cases). Some particular aspects of colicin sensitivity in strains isolated from 2 subjects of the same focus are pointed out and the significance of this market for epidemiologicala strains were colicin sensitive. Three different patterns of colicin sensitivity were described and one of them was predominant (in 89% of cases). Some particular aspects of colicin sensitivity in strains isolated from 2 subjects of the same focus are pointed out and the significance of this market for epidemiological studies is discussed.

Bacteriological Techniques↗

PubMed1980

Studies concerning the sensitivity of Klebsiella strains to a set of Klebsiella bacteriocins.

Optimal crude preparations of Klebsiella bacteriocins were obtained bu U.V. irradiation of bacteriocin producer strains. Of 308 clinical isolates of Klebsiella 88.9% could be typed on the basis of their sensitivity to different Klebsiella bacteriocins. The method affords further development of bacteriocin typing as a suitable procedure for hospital epidemiological investigation.

Bacteriocins↗

PubMedDate not supplied

[Bacteriocins and their ecological position].

The author discusses the position of bacteriocins in ecology on the basis of the data accumulated to date in the speciality literature, referring to: (a)the great and varied number of bacteriocinogenic bacterial strains; (b)the classification of bacteriocins in terms of their structure, chemical composition and physico-chemical properties; (c)spectrum of activity; (d)elements of differentiation and similarity with other ecologic systems (virsuses, the genetic entities of other microorganisms, interrelations, bacteriocinogeny and certain genetic recombination phenomena). Bacteriocinogeny is regarded as a biologic process, the result of natural selection. Stress is laid on the importance of the bacteriocinogenic and bacteriocinosensitive properties, next to the lysogeny of bacteria, for the classification of microorganisms. It is foreseen that in the future purified bacteriocins may perhaps be used in therapy, at least in certain cases.

Bacteria↗

PubMedDate not supplied

[Bacteriocin-bacteriophage interrelations].

The present paper refers to levels of morphological, serological and genetic similarity in bacteriocinogenic-lysogenic interrelationships, the similarity of the means of inducing bacteriocinogenic and lysogenic properties and the similarity of adsorption on specific cellular receptors. Nevertheless, bacteriocins and bacteriophages are still considered as agents of a different nature. Bacteriocins, with their varied chemical structure, are inert, whereas phages are complex chemical units with a nucleic acid nucleus and the capacity of self replication.

Bacteriocins↗

PubMedDate not supplied