For the determination of mycobacterial abundance, we made observations on a total of 30 A. polyphaga trophozoites for each check details of the 8 MAC species. In order to determine the total number of mycobacteria per trophozoite, we recorded the total number of vacuoles with one Mycobacterium organism and the total number of vacuoles with > 1 Mycobacterium organism. We also made observations on a total of 30 A. polyphaga organisms for each

of the 8 MAC species in order to determine their intracystic location, which was considered as intracystic when apposed to the cyst wall and reaching into the cyst wall (between the endo- and the exocyst). These observations were performed in triplicate. Statistical tests Comparison among amoeba-resistant bacterial species [2] as for their survival within exocyst was done using the χ2 test and corrected by Mantel Haenszel method. Comparaisons of mean ± standard deviation of the number of infected vacuoles were done using the ANOVA test. A P value < 0.05 was considered to be significant. Acknowledgements The authors acknowledge Bernard Campagna

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