[Serovars, antimicrobial resistance and conjugative R plasmids of Salmonella isolated from human during the period of 1966-1986 in Tokyo. Research Group for Infectious Enteric Diseases].
We examined 4,739 isolates of Salmonella isolated from patients with gastroenteritis during the period of 1966-1986 in Tokyo for the incidences of serovars, antibiotic resistance and conjugative R plasmids. The period of study was divided into three: 1966-73 (early period), 1974-79 (middle period), and 1980-86 (late period). The predominant serovars were S. typhimurium (34.3%), Infantis (5.6%), Panama (4.9%) in the middle period, S. typhimurium (31.7%), Paratyphi B (9.4%), Litchfield (7.3%) in the late period. These results were consistent with serovars of isolates from healthy citizens. The frequency of resistant isolates was as high as 86.9% in the early period, mostly streptomycin (SM)- and tetracycline (TC)-resistant isolates, but decreased significantly in the middle and the late periods, to 53.3 and 39.4%, respectively. The percentages of ampicillin (ABPC)-, chloramphenicol (CP)-, and kanamycin (KM)-resistant isolates increased in the late period. Strains carrying conjugative R plasmids were isolated as frequently as 57.8% of the total isolates in 1973, but as less frequently as 6.7% in 1981 indicating that the rate was roughly proportional to the incidence of the drug resistant isolates. The rate, however, increased gradually after 1981. The predominant resistance pattern of the R plasmids was TC-resistance in the early period, gradually changed into multiple and finally to AP-, CP-, KM-, SM-, TC- and sulfonamides-resistance in the late period.
Horiuchi
S
S
Inagaki
Y
Y
Nakaya
R
R
Goto
N
N
Yoshida
Y
Y
Kusunoki
J
J
Ito
T
T
Ohashi
M
M
D003227:Conjugation, Genetic; D004352:Drug Resistance, Microbial; D005759:Gastroenteritis / Q000382:microbiology; D006801:Humans; D011815:R Factors; D012475:Salmonella / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D012703:Serotyping; D013997:Time Factors; D014041:Tokyo