Anti-chlamydial IgG Neutralizing Ability in Nonzoonotic Atypical Community Acquired Respiratory Tract Infections.

Chlamydophila pneumoniae is a pathogenic agent, involved in various types of infection. This study has evaluated the ability of IgG antibodies in outpatient, with acute respiratory tract infections from C. pneumoniae, to neutralize in vitro purified elementary bodies of this bacterium, revealing a good neutralizing performance of IgG antibodies.

In vitro activities of several antimicrobial agents against recently isolated and genotyped Chlamydia trachomatis urogenital serovars D through K.

A systematic evaluation of the susceptibility of all Chlamydia trachomatis urogenital serovars (D through K) to levofloxacin, erythromycin, doxycycline, clarithromycin, and azithromycin was performed. All C. trachomatis serovars had comparable susceptibilities with respect to the various antimicrobials tested, thus confirming the homogeneous data so far obtained regarding the susceptibility of C.

Increasing effect of a high dose of PG-1 peptide on the infectivity of Chlamydophila abortus.

Cathelicidins are antimicrobial peptides, stored by mammalian leukocytes, showing an antimicrobial activity against bacteria, fungi, protozoa and enveloped viruses. In accordance with other authors, we reported in a previous study that the protegrin-1 (PG-1), at 80 microg mL(-1), inhibited the in vitro growth of Chlamydia trachomatis serovars D, H and L2; however, we observed an increased infectivity of some animal chlamydial species after their treatment with the same PG-1 concentration. In this study, the treatment of LLC-MK2 cells with PG-1 before chlamydial infection resulted in an increased infectivity of Chlamydophila abortus probably due to their easier entry into the host cells, whereas no increase in S26/3 infectivity was detected in LLC-MK2 cells treated with PG-1 postchlamydial infection.

Sensitivity of Chlamydia suis to cathelicidin peptides.

Nine Chlamydia suis isolates, obtained from pigs with conjunctivitis, were molecularly characterized by ompA sequencing and their in vitro susceptibility to six cathelicidin peptides (SMAP-29, BAC-7, BMAP-27, BMAP-27, BMAP-28, PG-1, LL-37) determined in cell culture. SMAP-29 was the most active peptide, reducing the intracellular inclusion number by > or =50% at a concentration of 10 microg/ml (3 microM) in six of the nine isolates tested. Three molecularly identical isolates were insensitive at a concentration as high as 80 microg/ml (25 microM).