Emergence of rifampin-resistant Rhodococcus equi with several types of mutations in the rpoB gene among AIDS patients in northern Thailand.
The antimicrobial susceptibilities of 30 Rhodococcus equi isolates obtained from 30 patients between 1993 and 2001 in northern Thailand were investigated. The MICs showed a tendency toward resistance to various antibiotics but sensitivity to imipenem, minocycline, vancomycin, and teicoplanin (MICs, </=0.5 micro g/ml) and relative sensitivity to meropenem, clarithromycin, and ciprofloxacin (MICs, </=2 micro g/ml). Of the 30 isolates, 26 were susceptible (MICs, </=1 micro g/ml), 1 showed low-level resistance (MIC, 8 micro g/ml), and 3 showed high-level resistance (MICs, >/=64 micro g/ml) to rifampin. PCR amplification and DNA sequencing of the rpoB gene and molecular typing by pulsed-field gel electrophoresis (PFGE) were performed for eight R. equi isolates from eight AIDS patients with pneumonia or lung abscess caused by R. equi between 1998 and 2001, including one low- and three high-level rifampin-resistant isolates. As a result, two high-level rifampin-resistant strains with PFGE pattern A had a Ser531Trp (Escherichia coli numbering) mutation, and one high-level rifampin-resistant strain with PFGE pattern B had a His526Tyr mutation, whereas one low-level rifampin-resistant strain with PFGE pattern C had a Ser509Pro mutation. Four rifampin-susceptible strains with PFGE patterns D and E showed an absence of mutation in the rpoB region. Our results indicate the presence of several types of rifampin-resistant R. equi strains among AIDS patients in northern Thailand.
Asoh
Norichika
N
Department of Internal Medicine, Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan. nori-a@net.nagasaki-u.ac.jp
Watanabe
Hiroshi
H
Fines-Guyon
Marguerite
M
Watanabe
Kiwao
K
Oishi
Kazunori
K
Kositsakulchai
Weerayut
W
Sanchai
Tippaya
T
Kunsuikmengrai
Khemrassamee
K
Kahintapong
Sumpun
S
Khantawa
Banyong
B
Tharavichitkul
Prasit
P
Sirisanthana
Thira
T
Nagatake
Tsuyoshi
T
D017088:AIDS-Related Opportunistic Infections / Q000453:epidemiology* / Q000382:microbiology*; D000193:Actinomycetales Infections / Q000453:epidemiology / Q000382:microbiology; D000328:Adult; D000818:Animals; D000904:Antibiotics, Antitubercular; D012321:DNA-Directed RNA Polymerases / Q000235:genetics*; D024881:Drug Resistance, Bacterial; D005260:Female; D006801:Humans; D008169:Lung Abscess / Q000382:microbiology; D008297:Male; D008826:Microbial Sensitivity Tests; D009154:Mutation; D018410:Pneumonia, Bacterial / Q000453:epidemiology / Q000382:microbiology; D016929:Rhodococcus equi / Q000187:drug effects* / Q000302:isolation & purification; D012293:Rifampin / Q000494:pharmacology*; D013785:Thailand / Q000453:epidemiology
D000904:Antibiotics, Antitubercular; D012321:DNA-Directed RNA Polymerases; C105078:RNA polymerase beta subunit; D012293:Rifampin