Molecular mechanisms of high level tetracycline-resistance in group A streptococcal isolates, T serotypes 4 and 11.
The molecular mechanism of high level tetracycline resistance in T serotypes 4 and 11 group A streptococcal (GAS) isolates was examined in 61 tetracycline-resistant isolates in Japan. PCR and sequencing analyses revealed that the T serotype/emm genotype, T4/4 isolates carried tet(O) genes, which were genetically homogenous. The T11/11 and T11/89 isolates carried different subtypes of tet(M) genes, which were present on transposons Tn916 and Tn1545, respectively. In addition, these T11 isolates may have obtained the tet(M) gene after the 1990s, because resistance to tetracycline in T11 isolates was rarely found before then. These results strongly suggested that the T4 and T11 GAS isolates acquired tetracycline-resistance via different molecular mechanisms.
Matsumoto
Masakado
M
Department of Microbiology, Aichi Prefectural Institute of Public Health, Nagoya 462-8576, Japan. eiseiken@pref.aichi.lg.jp
Sakae
Kenji
K
Ohta
Michio
M
Endo
Miyoko
M
Okuno
Rumi
R
Murayama
Shoko
S
Hirasawa
Kyoko
K
Suzuki
Rieko
R
Isobe
Junko
J
Tanaka
Daisuke
D
Katsukawa
Chihiro
C
Tamaru
Aki
A
Tomita
Masaaki
M
Ogata
Kikuyo
K
Yasuoka
Tomihisa
T
Ikebe
Tadayoshi
T
Watanabe
Haruo
H
D001426:Bacterial Proteins / Q000235:genetics*; D002352:Carrier Proteins / Q000235:genetics*; D004251:DNA Transposable Elements; D016521:Electrophoresis, Gel, Pulsed-Field; D005838:Genotype; D006801:Humans; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length; D017422:Sequence Analysis, DNA; D012703:Serotyping; D013297:Streptococcus pyogenes / Q000145:classification / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D013753:Tetracycline Resistance / Q000235:genetics*
D001426:Bacterial Proteins; D002352:Carrier Proteins; D004251:DNA Transposable Elements; C083138:Tet M resistance protein, Bacteria; C083139:Tet O resistance protein, Bacteria