ABSTRACT 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 μg/ml) and relative sensitivity to meropenem, clarithromycin, and ciprofloxacin (MICs, ≤2 μg/ml). Of the 30 isolates, 26 were susceptible (MICs, ≤1 μg/ml), 1 showed low-level resistance (MIC, 8 μg/ml), and 3 showed high-level resistance (MICs, ≥64 μg/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.
Binding of D-Penicillamine (D-Pen) to human monocytes was examined by flow cytometry with fluorescent D-Pen conjugate. Cells from HLA DR1-positive healthy females bound significantly more D-Pen than cells from DR1-negative healthy females (P = 0.015), and DR1 was associated with the highest binding among HLA DR antigens. In contrast, DR4 was associated with the lowest binding in healthy females. A difference in D-Pen binding between healthy females who were DR1-positive, DR4-negative and those who were DR1-negative, DR4-positive was statistically significant (P = 0.026). Neither healthy females nor healthy males showed significant associations of D-Pen binding with HLA A, B, or C antigens, nor did healthy males show an association between strength of D-Pen binding and any DR antigens.
gel electrophoresis (PFGE) type Staphylococcus aureus, especially methicillin-resistant S. aureus (MRSA), is an important nosocomial pathogen.In particular, MRSAis of great concern in both hospitals and nursing homes (1-3).Previous studies showed that the types of S. aureus in the hospital environment infrequently match-ed those colonizing inpatients (1).However, little information, including molecular analysis, is available regarding the relationship between colonization and S. aureus environ-
Transmission between human and environmental contamination from colonized methicillin-resistant Staphylococcus aureus (MRSA) remains a controversial issue. We, therefore, investigated the differences between MRSA types which colonize in humans and in the environment.A 4-week prospective culture survey for MRSA was performed for 12 patients as well as for the environment of the room of MRSA carriers in quarantine in the geriatric long-term care ward of a 270-bed hospital.A total of 97 S. aureus strains (80 MRSA and 17 methicillin-sensitive Staphylococcus aureus [MSSA]) was isolated during the periods of September 8 to 10, 23 to 25 and October 5 to 7, 1998; 25 strains were from the respiratory tract, 4 strains from feces and 11 strains from decubitus ulcers. Fifty-seven strains were from the patients' environment. Molecular typing by pulsed-field gel electrophoresis (PFGE) with the Sma I restriction enzyme demonstrated that the predominant type of MRSA isolated from the environment changed by the minute. The patterns of 42 MRSA strains isolated from the environment were identical in 26 (61.9%), closely related in 15 (35.7%) and possibly related in 1 (2.4%) of the cases of those isolated from patients simultaneously. There was no correlation between patients and the environment with the 17 MSSA isolates.Our results demonstrated that MRSA from patients can contaminate the environment, whereas MRSA from the environment might be potentially transmitted to patients via health care workers under unsatisfactory infection control.
