E test for studying in vitro activity of seven antimicrobial agents against penicillin-susceptible and penicillin-resistant pneumococci

To evaluate the comparative activity of seven oral antimicrobial agents against 100 strains of Streptococcus pneumoniae (S pneumoniae) Methods Total 100 strains of S pneumoniae were collected from general hospitals in Beijing from June 1996 to June 1997 E test method was used to detect the minimum inhibitory concentration (MIC) values of the following seven drugs against S pneumoniae : penicillin, amoxicillin/clavulanate, cefaclor, cefuroxime, ceftriaxone, azithromycin and ofloxacin The breakpoint of susceptibility categories was defined according to NCCLS Results 74% of isolates were susceptible (S, MIC 0 06?mg/L) to penicillin, and 5% were penicillin resistant (R, MIC 2?mg/L). The intermediately resistant (I, MIC 0 1-1?mg/L) rate to penicillin was 21% The total rates of R or I were 26% for penicillin, 6% for both amoxicillin/clavulanate and ceftriaxone, 9% for cefuroxime, 66% and 68% for azithromycin and ofloxacin respectively Overall 94%, 94% and 91% of the pneumococcal isolates were susceptible to amoxicillin/clavulanate, ceftriaxone and cefuroxime respectively S pneumoniae was highly resistant to azithromycin tested as a representative of macrolides (MIC 50 and MIC 90 both >256?mg/L, R rate 66%), and had a highly intermediately resistant rate to ofloxacin (I rate 62%) Conclusions Our data suggest that in vitro activity of oral amoxicillin/clavulanate was as good as ceftriaxone and cefuroxime It can be considered as an alternative compound in the treatment of community acquired pneumoniae and other respiratory tract infections caused by multiresistant S pneumoniae

Prevalence of antimicrobial resistance of Streptococcus pneumoniae in Chinese children: four hospitals surveillance

Objective To investigate the nasal carriage of antibiotic-resistant pneumococci in children of < 5 years old in the following four cities, Beijing, Shanghai, Guangzhou and Xi' an.Methods A total of 647 pneumococci strains were isolated and detected. Minimal inhibition concentrations (MICs) of antibiotics were determined by E-test. Disk diffusion test was used for the measurement of antimicrobial susceptibility.Results Prevalence of penicillin non-susceptible Streptococcus pneumoniae in the four cities was 41%, with Guangzhou (60.8%) ranking first, followed by Xi' an (45%), Shanghai (37%) and Beijing (25. 9%). The majority of penicillin non-susceptibility isolates (23. 9% -53. 8%) had a low level of resistance (MIC 0. 64 -1. 5 μg/ml). The most sensitive antimicrobials in terms of percentage of susceptible organisms were amoxicillin-clavulanic acid ( 99.4%), followed by ceftriaxone (92. 1 %); cefurxime and cefaclor were slightly more sensitive than penicillin with susceptibility of 74. 8% and 77. 9%. Erythromycin, tetracycline and TMP-SMZ were highly resistant (83. 6% , 82. 1% and 76.2% respectively) . Among erythromycin resistant isolates, 100% were resistant to azithromycin, 98.6% to clarithromycin, 97.2% to roxithromycin and spiramycin, and 96.6% to clindamycin. 97.2% (141/145) were typical of the macrolides-lincosamides-streptogramons B (MLSB ) resistance phenotype, and 2. 8% (4/145) were M phenotype. The group of PRSP was with significantly higher rates of non-susceptibility for ceftriaxone (18. 4%), cefurxime (58. 6%), cefaclor (53. 4%), compared with the group of PEN-S (0. 5% , 1.8% and 0. 2% , respectively) and the rate of multi-drug resistance in the isolates of PRSP group (92. 9%) was significantly higher than that of PEN-S group (59.2%).Conclusion The rates of penicillin and multi-drug resistance among isolates of pneumococci carried nasally in are high children and the high prevalence of multi-drug resistance in the Chinese population may be becoming one of the most serious problems in this century.