typhimurium by agar well diffusion method
(4 mg crude extract/well).
All isolates were resistant to oxacillin, penicillin, fosfomycin, ampicillin, and erythromycin and susceptible to vancomycin, teicoplanin, gentamicin, netilmicin, chloramphenicol, imipenem, rifampin, tetracycline, amoxicillin/clavulanate, and ciprofloxacin, as determined by disk diffusion method
performed on Mueller-Hinton agar.
The carbapenem-hydrolyzing enzyme was inhibited by clavulanic acid, as shown by the disk diffusion method
and confirmed by the IEF overlay method, similar to the other class A carbapenem-hydrolyzing enzymes (1,2).
The disk diffusion method
is widely used in Brazil and worldwide.
In preliminary tests of antimicrobial activity, we adopted the agar disc diffusion method
standardized by the WHO report (1977 in .
However, these studies were done using the disc diffusion method
of antimicrobial susceptibility testing on which problems have been highlighted in another studies (2).
Susceptibilities of Salmonella isolates to ampicillin, cefotaxime, chloramphenicol, ciprofloxacin, and trimethoprim-sulfamethoxazole were determined by the disk diffusion method
For the disc diffusion method
, Ciprofloxacin (40 [micro]g/disc) served as positive control for S.
Susceptibilities of 9 confirmed isolates to ceftazidime, chloramphenicol, colistin sulfate, gentamicin, minocycline, piperacillin/tazobactam, and trimethoprim-sulfamethoxazole were determined by using a disk diffusion method
isolates were screened for ESBL production by Kirby- Bauer's disc diffusion method
(6) demonstrating reduced susceptibility to cefpodoxime (30 [micro]g), cefotaxime (30 lag), ceftazidime (30 [micro]g), and aztreonam (30 [micro]g).
The predominant isolates from stool samples obtained for routine examination were cultured, and initial screening for ESBL production was conducted by using the disk diffusion method
according to NCCLS guidelines (3).
Later, a variety of diffusion techniques were tried and tested of which paper disk diffusion method
has stood test of time.