Comparison of three different PCR-based methods to predict the penicillin nonsusceptible Streptococcus pneumoniae
1Department of Respiratory Medicine, Jinling Hospital, School of Medicine, Nanjing University, Nanjing, People's Republic of China.
Aim:
To find a quick and reliable diagnostic technique for penicillin nonsusceptible Streptococcus pneumoniae (PNSSP) from Nanjing, China.
Methods And Results:
A total of 130 S. pneumoniae clinical isolates and 50 healthy carriers' isolates were collected from seven teaching hospitals in Nanjing between March 2005 and June 2007. Three different methods, PCR, seminested-PCR, and PCR-RFLP, were applied in detecting PNSSP. The prevalence of PNSSP was 73.9%, the penicillin-resistance rate of children's group and adults' group were 87.8% and 31.2%, respectively. The PCR method had difficulty in identifying intermediate-resistant and resistant isolates, the PCR-RFLP method could only be used for susceptible isolates and had poor sensitivity. Seminested-PCR was fast, sensitive for detection, and successfully differentiated between moderately and highly resistant S. pneumoniae; 96.1% of the PCR results were in agreement with the minimum inhibitory concentration (MIC) data.
Conclusions:
The penicillin resistance rate in isolates from children was much higher than of isolates from adults in China. Seminested-PCR for pbp1A was the best diagnostic method.
Significance And Impact Of The Study:
We compared three different strategies for the first time in identification of PNSSP in China. In conclusion, seminested-PCR can be applied in clinical microbiology laboratories for detection of serious infections caused by S. pneumoniae.