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N Nacescu

Publications and source records attributed to N Nacescu.

10 recordsLinked to original sources
PubMed1998

Changes in Vibrio cholerae O1 strains isolated in Romania during 1977-95.

Six hundred and twenty-four Vibrio cholerae O1 strains, 623 serotype Ogawa and one serotype Inaba, isolated in Romania between 1977-95 were tested to detect all changing traits concerning serogroup, serotype, biotype, phage type and resistotype patterns and subsequently, the possible epidemiological relationship among these strains. Biotyping revealed one classical, 580 eltor strains and 43 intermediary variants. When tested with Mukerjee phages, 546 (87%) strains were sensitive and 78 (13%) resistant. One phage type (M4) dominated during 1977-90, two phage types (M4 and M5) exhibited the same high frequencies during 1991, a diversity of types occurred during 1993-4 whereas in 1995, two phage types (M4 and M5) showed similar distributions again. Five patterns of drug susceptibility were successively described during 1977-95. The most prominent changes in Vibrio cholerae O1 strains were noticed during 1993-4: the highest number of non-typable strains and intermediary variants, the widest spectrum of phage types and of multidrug resistance. In 1995, the strains reverted to the previous typable forms but a new drug resistance pattern was noticed.

Bacterial Typing Techniques↗
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↗
PubMed1983

The newly described pathogenic species Vibrio mimicus isolated from human diarrhoeal stools and from a sea water sample.

Four Vibrio strains have been isolated from three patients presenting diarrhoea as well as from a sea water sample; identification proved their belonging to Vibrio mimicus, a recently described new pathogenic species. The morpho-cultural and biochemical characteristics of the isolated strains are presented. The distribution and incidence of this newly described species in Romania are under study.

Anti-Bacterial Agents↗
PubMed1977

Demonstration of enterobacterial common antigen by bacterial agglutination.

Potent antisera against the enterobacterial common antigen (ECA) agglutinate R bacteria of the Enterobacteriaceae family that possess unimpaired R-core structures of the Escherichia coli R1 or E. coli R4 core type. In these strains, known to be ECA immunogenic, ECA is most probably linked to the lipopolysaccharide R core. R mutants of other core types (e.g., Salmonella Ra, E. coli R2 or R3) or R mutants with incomplete core structures of the E. coli R1 type, as well as an rfaL mutant deficient in the O-translocase system, agglutinate to a much lesser extent or not at all. All the later mutants are nonimmunogenic; they possess the ECA in a free form, not linked to the R core. None of the S forms tested from many different enterobacterial genera was found to be agglutinable with the ECA antiserum. The dynamics of the ECA agglutinin formation in rabbits parallels the ECA hemagglutinin formation, indicating that the same antibody class might be involved in bacterial agglutination and hemagglutination.

Agglutination↗
PubMedDate not supplied

Molecular characterization of Vibrio cholerae O1 strains isolated in Romania.

A collection of 89 Vibrio cholerae O1 strains, isolated in Romania between 1977 and 1994, and 6 strains from the Republic of Moldavia, was characterized by ribotyping, toxin gene restriction pattern (toxinogenotype) and distribution of cholera toxin gene (ctx), accessory toxin gene (ace) and zonula occludens toxin gene (zot). After Bg/I endonuclease restriction of chromosomal DNA, a total of 18 ribotypes and 21 toxinogenotypes were distinguished. Deletions in the core region of the toxin gene cassette were found in 20% of strains; however, with the exception of one strain, all the isolates contained the ctx gene. Used in association, the three methods of molecular typing provided an accurate characterization of V. cholerae O1 isolates.

Bacterial Typing Techniques↗
PubMedDate not supplied

Studies on the hemagglutinant activity of some Aeromonas strains.

216 strains to Aeromonas genus (158 A. hydrophila, 33 A. salmonicida, 23 A. sobria, 1 A. caviae and 1 A. veronii strains) of different sources of isolation were studied concerning their hemagglutinating behaviour to 5 different erythrocyte species (human, bovine, chicken, African green monkey and guinea pig) in the presence/absence of mannose/fucose. The study aimed to establish the spectrum of their hemagglutinating activity and any possible correlation between the source of isolation, biochemical phenotype LDC VP and HA type/subtype. Different aspects of HA type/subtype and phenotype LDC VP of Aeromonas strains are discussed. Four Aeromonas hydrophila strains isolated from pig enteritis exhibited constantly FRHA to bovine erythrocytes suggesting a possible correlation between virulence and HA type of the respective strains.

Aeromonas↗