obligate intracellular parasite intracellular obligate intracellular obligate intracellular parasite Obligate intracellular parasite obligate intracellular parasite obligate intracellular obligate intracellular obligate intracellular obligate intracellular obligate intracellular parasite obligate intracellular intracellular obligate intracellular obligate intracellular bacteria obligate intracellular parasite