ABSTRACT
BACKGROUND: Panton-Valentine leukocidin (PVL) is a pore-forming toxin secreted by some Staphylococcus aureus strains and associated with skin and soft tissue infections; these strains are epidemiologically associated with current outbreaks of community-acquired methicillin-resistant S. aureus (MRSA) and with necrotizing pneumonia in healthy adults in USA and Europe. This study was performed to investigate the presence of PVL-positive S. aureus and the significant infections known to be caused by this organism. METHODS: A total of 573 strains of S. aureus blood isolates at university-affiliated hospital during 2002 to 2005 were selected. The presence of PVL was investigated using PCR. Additional 12 staphylococcal toxin genes were also examined in PVL-positive S. aureus strains, and MRSA isolates were typed for the staphylococcal cassette chromosome mec (SCCmec). RESULTS: PVL genes were detected in 5 (0.9%) of 573 S. aureus strains, including 1 MRSA and 4 MSSA. The PVL-positive MRSA isolate was SCCmec type IV, and no other staphylococcal toxins were detected. The median age of the patients infected with PVL-positive S. aureus was 36 yr. Three cases of bacteremia were preceded by skin and soft-tissue infections. CONCLUSIONS: Bacteremia caused by PVL-positive S. aureus strain were detected in 5 patients in Korea, and some of the patients were associated with severe skin and soft-tissue infections. In addition, the PVL-positive MRSA strain of SCCmec type IV, a characteristic of community-acquired MRSA isolates in USA and Europe, also exists in Korea, and can cause the severe infections known to be associated with this organism.
Subject(s)
Adult , Female , Humans , Male , Middle Aged , Bacteremia/microbiology , Bacterial Proteins/genetics , Bacterial Toxins/blood , Exotoxins/blood , Korea , Leukocidins/blood , Methicillin/pharmacology , Methicillin Resistance/drug effects , Polymerase Chain Reaction/methods , Staphylococcal Infections/microbiology , Staphylococcus aureus/geneticsABSTRACT
BACKGROUND: Panton-Valentine leukocidin (PVL) is a pore-forming toxin secreted by some Staphylococcus aureus strains and associated with skin and soft tissue infections; these strains are epidemiologically associated with current outbreaks of community-acquired methicillin-resistant S. aureus (MRSA) and with necrotizing pneumonia in healthy adults in USA and Europe. This study was performed to investigate the presence of PVL-positive S. aureus and the significant infections known to be caused by this organism. METHODS: A total of 573 strains of S. aureus blood isolates at university-affiliated hospital during 2002 to 2005 were selected. The presence of PVL was investigated using PCR. Additional 12 staphylococcal toxin genes were also examined in PVL-positive S. aureus strains, and MRSA isolates were typed for the staphylococcal cassette chromosome mec (SCCmec). RESULTS: PVL genes were detected in 5 (0.9%) of 573 S. aureus strains, including 1 MRSA and 4 MSSA. The PVL-positive MRSA isolate was SCCmec type IV, and no other staphylococcal toxins were detected. The median age of the patients infected with PVL-positive S. aureus was 36 yr. Three cases of bacteremia were preceded by skin and soft-tissue infections. CONCLUSIONS: Bacteremia caused by PVL-positive S. aureus strain were detected in 5 patients in Korea, and some of the patients were associated with severe skin and soft-tissue infections. In addition, the PVL-positive MRSA strain of SCCmec type IV, a characteristic of community-acquired MRSA isolates in USA and Europe, also exists in Korea, and can cause the severe infections known to be associated with this organism.
Subject(s)
Adult , Female , Humans , Male , Middle Aged , Bacteremia/microbiology , Bacterial Proteins/genetics , Bacterial Toxins/blood , Exotoxins/blood , Korea , Leukocidins/blood , Methicillin/pharmacology , Methicillin Resistance/drug effects , Polymerase Chain Reaction/methods , Staphylococcal Infections/microbiology , Staphylococcus aureus/geneticsABSTRACT
BACKGROUND & OBJECTIVE: Anthrax has been reported from almost every country and India is endemic for this disease. There is considerable under reporting of the disease because of lack of microbiological facilities and diagnostic reagents. In India only conventional methods which have limitations, are being used to diagnose the disease. Hence the aim of this study was to isolate and purify protective antigen (PA) using different protocols and to use this PA for detection of anti-PA antibodies from sera samples. METHODS: Protective antigen was isolated and purified from the Sterne strain of Bacillus anthracis. B. anthracis lacking pXO1 and pXO2 transformed with pYS5 (B. anthracis pYS5) and recombinant Escherichia coli transformed with pQE30 containing PA gene using hydroxyapatite (HA), Q-sepharose fast protein liquid chromatography (FPLC) and nickel-nitrilotriacetic acid (Ni-NTA) chromatographic methods, respectively. A mixture of PA and edema factor (EF) was injected subcutaneously into rabbits to test the biological activity of PA. The immunogenicity of PA was tested by inoculating the protein into rabbits along with adjuvant. Using this PA, 20 bovine sera samples (pre- and post-vaccinated) were tested by Western blotting (WB) for the presence of anti-PA antibodies. RESULTS: The 83 kDa PA protein was obtained from all the bacteria with the yields of 13, 50 and 9.0 mg/l from Sterne B. anthracis, B. anthracis pYS5 and recombinant Esch. coli, respectively. Formation of edematous ulcers at the site of PA+EF injection clearly confirmed the retention of biological activity of the proteins. Of the 10 post-vaccination sera tested, 9 showed clear positive by WB whereas none of the pre-vaccination sera showed the reaction. INTERPRETATION & CONCLUSION: The purified PA preparations obtained in the present study may possibly be utilized for detection of anti-PA antibodies in the sera of anthrax patients for timely diagnosis of the disease and, might also be tested for their efficacy and use as human anthrax vaccine.