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Mycobacterium tuberculosis complex mycobacteria as amoeba-resistant organisms.

Mba Medie F, Ben Salah I, Henrissat B, Raoult D, Drancourt M - PLoS ONE (2011)

Bottom Line: M. tuberculosis, M. bovis and M. avium mycobacteria were further entrapped within the double wall of <1% amoebal cysts, but no M. canettii organisms were observed in amoebal cysts.Mycobacteria survived in the cysts for up to 18 days and cysts protected M. tuberculosis organisms against mycobactericidal 5 mg/mL streptomycin and 2.5% glutaraldehyde.Intercystic survival of tuberculous mycobacteria, except for M. canettii, protect them against biocides and could play a role in their life cycle.

View Article: PubMed Central - PubMed

Affiliation: Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes, UMR 6236 CNRS-Université de la Méditerranée, IRD 189, IFR 48, Faculté de Médecine, Marseille, France.

ABSTRACT

Background: Most environmental non-tuberculous mycobacteria have been demonstrated to invade amoebal trophozoites and cysts, but such relationships are largely unknown for members of the Mycobacterium tuberculosis complex. An environmental source has been proposed for the animal Mycobacterium bovis and the human Mycobacterium canettii.

Methodology/principal findings: Using optic and electron microscopy and co-culture methods, we observed that 89±0.6% of M. canettii, 12.4±0.3% of M. tuberculosis, 11.7±2% of M. bovis and 11.2±0.5% of Mycobacterium avium control organisms were phagocytized by Acanthamoeba polyphaga, a ratio significantly higher for M. canettii (P = 0.03), correlating with the significantly larger size of M. canetti organisms (P = 0.035). The percentage of intraamoebal mycobacteria surviving into cytoplasmic vacuoles was 32±2% for M. canettii, 26±1% for M. tuberculosis, 28±2% for M. bovis and 36±2% for M. avium (P = 0.57). M. tuberculosis, M. bovis and M. avium mycobacteria were further entrapped within the double wall of <1% amoebal cysts, but no M. canettii organisms were observed in amoebal cysts. The number of intracystic mycobacteria was significantly (P = 10(-6)) higher for M. avium than for the M. tuberculosis complex, and sub-culturing intracystic mycobacteria yielded significantly more (P = 0.02) M. avium organisms (34×10(4) CFU/mL) than M. tuberculosis (42×10(1) CFU/mL) and M. bovis (35×10(1) CFU/mL) in the presence of a washing fluid free of mycobacteria. Mycobacteria survived in the cysts for up to 18 days and cysts protected M. tuberculosis organisms against mycobactericidal 5 mg/mL streptomycin and 2.5% glutaraldehyde.

Conclusions/significance: These data indicate that M. tuberculosis complex organisms are amoeba-resistant organisms, as previously demonstrated for non-tuberculous, environmental mycobacteria. Intercystic survival of tuberculous mycobacteria, except for M. canettii, protect them against biocides and could play a role in their life cycle.

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Difference in the mechanism of interaction between MTC and M. avium.Comparison of the size of mycobacteria by electron microscopy. M. bovis (A), M. avium (B), M. tuberculosis (C) and M. canettii (D). “*” denotes significant difference when comparing the size of M. canettii and that of the other species. Ma- Mycobacterium avium. Mb- Mycobacterium bovis. Mt- Mycobacterium tuberculosis. Mc- Mycobacterium canettii.
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pone-0020499-g005: Difference in the mechanism of interaction between MTC and M. avium.Comparison of the size of mycobacteria by electron microscopy. M. bovis (A), M. avium (B), M. tuberculosis (C) and M. canettii (D). “*” denotes significant difference when comparing the size of M. canettii and that of the other species. Ma- Mycobacterium avium. Mb- Mycobacterium bovis. Mt- Mycobacterium tuberculosis. Mc- Mycobacterium canettii.

Mentions: Light microscopy failed to reveal visible mycobacteria in A. polyphaga cysts three days after the induction of encystment, whereas electron microscopy observation of 300 such cysts showed M. tuberculosis, M. bovis, and M. avium organisms visible inside the A. polyphaga cysts (Fig. 4). As for these three species, we found <1% of cysts harboring mycobacteria visible in the space between the inner and outer wall of the cyst (Fig. 4A). M. bovis organisms were also observed on the inner side of the outer wall and in the cytoplasm of the cyst (Fig. 4C), as was the case for a few M. avium mycobacteria (Fig. 4D). The average number of mycobacteria per cyst was significantly higher (P = 10−6) for M. avium (5 bacilli/cyst) than for M. tuberculosis and M. bovis (1 bacillus/cyst). Further electron microscopy observation of up to 500 cysts failed to reveal any M. canettii organisms inside the A. polyphaga cysts. We further observed that a 48-hour exposure of the mycobacteria-infected cysts to 10 µg/ml streptomycin, used to kill extra-cystic mycobacteria, did not affect their excystment capacity, as new trophozoites emerged after a 7-day incubation in PYG medium at 33°C as determined by light microscopy. These cysts yielded significantly more (P = 0.02) M. avium organisms (34×104 CFU/mL) than M. tuberculosis (42×101 CFU/mL) and M. bovis (35×101 CFU/mL) in the presence of a washing fluid free of mycobacteria (Fig. 5). After the cysts were exposed to 2.5% glutaraldehyde, sub-culturing intracystic mycobacteria released 18×103 CFUs for M. avium and 220 CFUs for M. tuberculosis. A non-quantitative subculture further demonstrated that M. avium, M. tuberculosis and M. bovis organisms survived in the cysts of A. polyphaga for up to 18 days.


Mycobacterium tuberculosis complex mycobacteria as amoeba-resistant organisms.

Mba Medie F, Ben Salah I, Henrissat B, Raoult D, Drancourt M - PLoS ONE (2011)

Difference in the mechanism of interaction between MTC and M. avium.Comparison of the size of mycobacteria by electron microscopy. M. bovis (A), M. avium (B), M. tuberculosis (C) and M. canettii (D). “*” denotes significant difference when comparing the size of M. canettii and that of the other species. Ma- Mycobacterium avium. Mb- Mycobacterium bovis. Mt- Mycobacterium tuberculosis. Mc- Mycobacterium canettii.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3108610&req=5

pone-0020499-g005: Difference in the mechanism of interaction between MTC and M. avium.Comparison of the size of mycobacteria by electron microscopy. M. bovis (A), M. avium (B), M. tuberculosis (C) and M. canettii (D). “*” denotes significant difference when comparing the size of M. canettii and that of the other species. Ma- Mycobacterium avium. Mb- Mycobacterium bovis. Mt- Mycobacterium tuberculosis. Mc- Mycobacterium canettii.
Mentions: Light microscopy failed to reveal visible mycobacteria in A. polyphaga cysts three days after the induction of encystment, whereas electron microscopy observation of 300 such cysts showed M. tuberculosis, M. bovis, and M. avium organisms visible inside the A. polyphaga cysts (Fig. 4). As for these three species, we found <1% of cysts harboring mycobacteria visible in the space between the inner and outer wall of the cyst (Fig. 4A). M. bovis organisms were also observed on the inner side of the outer wall and in the cytoplasm of the cyst (Fig. 4C), as was the case for a few M. avium mycobacteria (Fig. 4D). The average number of mycobacteria per cyst was significantly higher (P = 10−6) for M. avium (5 bacilli/cyst) than for M. tuberculosis and M. bovis (1 bacillus/cyst). Further electron microscopy observation of up to 500 cysts failed to reveal any M. canettii organisms inside the A. polyphaga cysts. We further observed that a 48-hour exposure of the mycobacteria-infected cysts to 10 µg/ml streptomycin, used to kill extra-cystic mycobacteria, did not affect their excystment capacity, as new trophozoites emerged after a 7-day incubation in PYG medium at 33°C as determined by light microscopy. These cysts yielded significantly more (P = 0.02) M. avium organisms (34×104 CFU/mL) than M. tuberculosis (42×101 CFU/mL) and M. bovis (35×101 CFU/mL) in the presence of a washing fluid free of mycobacteria (Fig. 5). After the cysts were exposed to 2.5% glutaraldehyde, sub-culturing intracystic mycobacteria released 18×103 CFUs for M. avium and 220 CFUs for M. tuberculosis. A non-quantitative subculture further demonstrated that M. avium, M. tuberculosis and M. bovis organisms survived in the cysts of A. polyphaga for up to 18 days.

Bottom Line: M. tuberculosis, M. bovis and M. avium mycobacteria were further entrapped within the double wall of <1% amoebal cysts, but no M. canettii organisms were observed in amoebal cysts.Mycobacteria survived in the cysts for up to 18 days and cysts protected M. tuberculosis organisms against mycobactericidal 5 mg/mL streptomycin and 2.5% glutaraldehyde.Intercystic survival of tuberculous mycobacteria, except for M. canettii, protect them against biocides and could play a role in their life cycle.

View Article: PubMed Central - PubMed

Affiliation: Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes, UMR 6236 CNRS-Université de la Méditerranée, IRD 189, IFR 48, Faculté de Médecine, Marseille, France.

ABSTRACT

Background: Most environmental non-tuberculous mycobacteria have been demonstrated to invade amoebal trophozoites and cysts, but such relationships are largely unknown for members of the Mycobacterium tuberculosis complex. An environmental source has been proposed for the animal Mycobacterium bovis and the human Mycobacterium canettii.

Methodology/principal findings: Using optic and electron microscopy and co-culture methods, we observed that 89±0.6% of M. canettii, 12.4±0.3% of M. tuberculosis, 11.7±2% of M. bovis and 11.2±0.5% of Mycobacterium avium control organisms were phagocytized by Acanthamoeba polyphaga, a ratio significantly higher for M. canettii (P = 0.03), correlating with the significantly larger size of M. canetti organisms (P = 0.035). The percentage of intraamoebal mycobacteria surviving into cytoplasmic vacuoles was 32±2% for M. canettii, 26±1% for M. tuberculosis, 28±2% for M. bovis and 36±2% for M. avium (P = 0.57). M. tuberculosis, M. bovis and M. avium mycobacteria were further entrapped within the double wall of <1% amoebal cysts, but no M. canettii organisms were observed in amoebal cysts. The number of intracystic mycobacteria was significantly (P = 10(-6)) higher for M. avium than for the M. tuberculosis complex, and sub-culturing intracystic mycobacteria yielded significantly more (P = 0.02) M. avium organisms (34×10(4) CFU/mL) than M. tuberculosis (42×10(1) CFU/mL) and M. bovis (35×10(1) CFU/mL) in the presence of a washing fluid free of mycobacteria. Mycobacteria survived in the cysts for up to 18 days and cysts protected M. tuberculosis organisms against mycobactericidal 5 mg/mL streptomycin and 2.5% glutaraldehyde.

Conclusions/significance: These data indicate that M. tuberculosis complex organisms are amoeba-resistant organisms, as previously demonstrated for non-tuberculous, environmental mycobacteria. Intercystic survival of tuberculous mycobacteria, except for M. canettii, protect them against biocides and could play a role in their life cycle.

Show MeSH
Related in: MedlinePlus