Rapid assay for detection of chloramphenicol acetyl transferase in Haemophilus influenzae.
OBJECTIVE
Haemophilus influenzae causes a variety of life threatening infections in humans. Early detection of antimicrobial resistance is of importance in the treatment and management of infection. The modified Slack's method, a simple assay, has been evaluated in this study for the early detection of chloramphenicol resistance.


METHODS
Fifty isolates of H. influenzae from invasive and non-invasive sites were included. Antimicrobial susceptibility testing was done by disc diffusion method and minimum inhibitory concentration (MIC) determination was performed for chloramphenicol only. Modified Slack's method was used to test for the production of chloramphenicol acetyl transferase (CAT).


RESULTS
Invasive isolates showed higher degree of resistance to chloramphenicol (72%) compared to non-invasive ones (28%). One hundred per cent association was found between results of disc diffusion, MIC and CAT production amongst strains resistant to chloramphenicol.


CONCLUSIONS
The findings suggested that chloramphenicol still remains the drug of choice for treatment for non-invasive infection caused by H. influenzae. Modified Slack's method is a simple, rapid, inexpensive and reliable method for the detection of chloramphenicol resistance amongst H. influenzae.
Satish
N
N
Department of Microbiology, Christian Medical College & Hospital, Vellore, India.
Manoharan
A
A
Pai
R
R
Lalitha
M K
MK
D000328:Adult; D000368:Aged; D002675:Child, Preschool; D015500:Chloramphenicol O-Acetyltransferase / Q000032:analysis*; D002702:Chloramphenicol Resistance; D006193:Haemophilus influenzae / Q000737:chemistry*; D006801:Humans; D007223:Infant; D008826:Microbial Sensitivity Tests; D008875:Middle Aged
D015500:Chloramphenicol O-Acetyltransferase