Antibiotics, peptidoglycan synthesis and genomics: the chlamydial anomaly revisited

Peptidoglycan, which forms a sacculus around the majority of eubacteria, is an important cell wall polymer since interference with its synthesis or structure leads to loss of cell shape and integrity (Rogers et al., 1980). Nevertheless, some groups of eubacteria, such as the Thermatoga and Planctomyces, do not contain peptido-glycan in their walls and in such organisms other polymers impart structural integrity (Stackebrandt et al., 1984; Moulder, 1993; Shah et al., 1997). Chlamydiae, of which two species, Chlamydia tracho-matis and Chlamydia pneumoniae, are major pathogens for man, are obligate intracellular eubacteria (Schachter, 1992). They represent an interesting group of organisms differentiated from other bacteria by a unique devel-opment cycle involving two morphological forms, one