Preliminary study of randomly-amplified polymorphic DNA analysis for typing extended-spectrum beta-lactamase (ESBL)-producing Klebsiella pneumoniae

Objective: Extended-spectrum beta-lactamases (ESBLs) are most prevalent in Klebsiella pneumoniae. This organism is frequently isolated from clinical specimens and can cause septicemia, pneumonia or urinary tract infection. There were occasionally suspicious outbreaks of ESBL-producing K. pneumoniae in patients' wards. The objective is to determine whether the randomly amplified polymorphic DNA (RAPD), which is a polymerase chain reaction (PCR)-based typing technique, can be used as a typing method for studying the molecular epidemiology of ESBL-producing K. pneumoniae. Material and Method: The present study was carried out by using 30 ESBL-producing K. pneumoniae isolates obtained from different patients admitted to Siriraj Hospital between January and February 2004. RAPD was evaluated for three primers. All isolates were re-examined by using Southern blot hybridization. Results: It was found that 29 DNA band patterns were generated individually by either AP4 or HLWL74 and R108 primers (30 patterns) for RAPD analysis and 30 patterns for Southern blot hybridization with class 1 integron (intI1) probe. Different patterns indicated that these 30 isolates could not be the cause of an outbreak in Siriraj Hospital. Conclusion: The RAPD typing is good and can be used as a screening, rapid and inexpensive test for ESBL-producing K. pneumoniae during investigation of outbreaks.