Role of azithromycin against clinical isolates of family enterobacteriaceae: A comparison of its minimum inhibitory concentration by three different methods.
OBJECTIVE
To determine the effect of azithromycin, a new azalide antibiotic, on clinical isolates of the family Enterobacteriaceae and to determine and compare its minimum inhibitory concentration (MIC) by disk diffusion, agar dilution and E-test methods.


METHODS
One hundred fifty-nine bacterial strains belonging to the family Enterobacteriaceae, isolated from different clinical samples, were tested for their susceptibility to azithromycin by disk diffusion, agar dilution and E-test methods. The MIC values were analysed and the percentages of agreement between the different methods were mentioned.


RESULTS
Of the 159 isolates of the family Enterobacteriaceae, 60.37% were E. coli followed by Klebsiella species 28.3%, Salmonella and Shigella species 3.77% and Enterobacter and Citrobacter species 1.88% each. Maximum isolates were obtained from urine 117/159 (73.58%). Azithromycin was found to be more active against Salmonella and Shigella species, showing 100% sensitivity the by E-test and 83.33% by the disk diffusion methods. In the agar dilution method, 83.33% of Salmonella and 66.66% of Shigella species were sensitive to azithromycin. The overall agreement between disk diffusion and agar dilution method was 96.8%, between agar dilution and E-test was 88% and between disk diffusion and E-test was 91.2%.


CONCLUSIONS
Azithromycin may become an important addition to our antimicrobial strategies, especially for the treatment of bacterial diarrhoea and infections caused by Salmonella typhi.
Chayani
N
N
Department of Microbiology, S.C.B. Medical College, Cuttack, India. nirupama.chayani@gmail.com
Tiwari
S
S
Sarangi
G
G
Mallick
B
B
Mohapatra
A
A
Paty
B P
BP
Das
P
P
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D017963:Azithromycin / Q000494:pharmacology*; D004755:Enterobacteriaceae / Q000187:drug effects* / Q000302:isolation & purification; D004756:Enterobacteriaceae Infections / Q000382:microbiology*; D006801:Humans; D008826:Microbial Sensitivity Tests; D012680:Sensitivity and Specificity
D000900:Anti-Bacterial Agents; D017963:Azithromycin