Abstract:
Disk diffusion method (NCClS guideline) has been used for testing
the antimicrobial susceptibility of the pathogenic bacteria isolated
from clinical specimens in Microbiology laboratory, Ramathibodi
Hospital. The data has been collected manually at the beginning
(1971-1976) and by computer after that. The number of specimens
received was increased from 38,000 to 70,245 over a time period
from 1971 to 1998. In contrast to the increased isolation, Neisseria
gono"hoeae and Shigella flexneriwere decreased. Beta-Iactamase
producing N. gono"hoeae increased from 12% in 1973 to 68% in
1981 and H. influenzae from 16% in 1986 to 47% in 1998. An
increase in antimicrobial resistance was observed in Gram negative
bacilli; such as, E. coli to cotrimoxazole and nalidixic acid, K.
pneumoniae to imipenem and amikacin, S Typhi, S. sonnei and S.
flexneri to cotrimoxazole, and P. aeruginosa to cefoperazone,
ceftazidime, imipenem, ciprofloxacin, amikacin and gentamicin. The
isolation of Methicillin Resistant Staphylococcus aureus (MRSA)
increased from 14% in 1987 to 38% in 1994. We did not isolate any
vancomycin resistant strains of S. aureus during 1992-1998. The
resistance of S. aureus to fosfomycin increased suddenly from 3%
in 1997 to 7% in 1998. The isolation of Streptococcus pneumoniae
with MICs to penicillin 2 mcglml increased from 10.2% in 1994 to
15.6% in 1996 (E-test method).