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.