Keywords
Bacterial meningites
Antimicrobial
Susceptibility test
Betalactamics
How to Cite
Abstract
This study analyzes the effect of the inoculum concentration of Haemophilus influenzae strains to determine the antimicrobial susceptibility. A total 98 strains isolated from cerebrospinal fluid (CSF) was studied through the disk diffusion method and the minimal inhibitory concentration (MIC). The results showed that with the inoculum 108 UFC/mL, 56 strains were resistant to ampicillin, but with this inoculum diluted to 106 UFC/mL, 10 cepas of the strains were resistant to this antiobiotic in the disk diffusion method The correlation of the inoculum 108 UFC/ml and 106 UFC/ml in the disk diffusion method using disks containing ampicillin, cephalotin, cephoxitin, fosfomycin, penicillin and sulfamethoxazole/trimethoprim showed that the inoculum concentration is a significante factor in the strain susceptibility, mainly when testing betalactamic antibiotics. This observation led to a standardization of inoculum size at 106 UFC/mL when testing H. influenzae, in order to obtain dependable and reproducible results.
References
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