Streptococcus Pneumoniae Biological Characterization And Analysis Of Drug Resistance

Streptococcus pneumoniae (SP) are often colonizing in the nasopharynx of healthy individuals. Most of them are not pathogenic or pathogenic weakly, and only a few of them are pathogenic. SP is the common cause of bacterial pneumoniae, and pneumococcal infectious diseases are the causes of high morbidity and mortality worldwide. So, it is very important to collect streptococcus pneumoniae from clinical cases and healthy carriers, to analyze pneumococcal antibiotic-resistance and set up the bank of standard antibiotic resistant strain.21 strains of streptococcus pneumoniae were identified using automatic bacterial identification system out of the 202 nasopharyngeal isolates carried by healthy children collected from Beijing children hospital during 2000 to 2001. 3 of the 20 strains were excluded by both optochin test and bile solubility test. So 17 strains of streptococcus pneumoniae were identified finally. Other isolates were identified as following: 74 strains of streptococcus mitis, 7 strains of streptococcus oralis, 4 strains of streptococcus acidominimus, 2 strains of streptococcus sanguinis, 23 strains of pediococcus pentosaceus, 5 strains of pediococcus acidilactici, 1 strain of kytococcus sedentarius, 1 strain of gemella haemolysans, 1 strain of rothia dentocariosa, 1 strain of rothia mucilaginosa, 3 strains of acranobacterium haemolyticum, 45 strains of streptococcus mitis/pneumoniae.The drug sentivity of pneumococcal isolates, including 17 strains of SP isolated this time and 189 pathogenic isolates in 1980s', was measured with the minimal inhibitory concentration (MIC) against 16 kinds of antibiotics using microdilution methods. The antibiotic resistant SP strains were identified as following, 4 penicillin-non-sensitive strains(1 of them resistant to other β -lactam drugs meantime), 23 erythromycin-insensitive strains, 28 azithromycin-insensitive strains, 190 tetracycline-insensitive strains, 24 of loxacin-intermediate strains, 124 trimethoprim/sulfamethoxazole-insensitive strains, 101 chloramphenicol-resistant strains, 15 clidamycin-resistant strains. There is significant diffidence between the antibiotic sensitivity of streptococcus pneumoniae collected in 2000~2001 and in 1980s' . As times spent, the rates of antibiotic resistance is getting higher to β-lactam, carbapenems,co-trimoxazole, macrolides and lincosamides ; declined for tetracycline and chloramphenicol. Rifampin or vancomycin resistant streptococcus pncumoniae is not yet found so far.