Growth and Development of Tetracycline-Resistant Chlamydia suis

Tetracycline Resistance inChlamydia suisMediated by Genomic Islands Inserted into the Chlamydialinv-Like Gene

“…However, stable Tc r C. suis strains have recently been identified in both diseased and apparently healthy pigs from farms across the midwestern United States. The resistance properties of these strains were confirmed in three laboratories (1,20,35), but the mechanism of resistance had not been elucidated.…”

Chlamydial Persistence: beyond the Biphasic Paradigm

“…In some cases, the explanation for resistance could be more complex; certain genotypes could confer antibiotic resistance by encouraging development of the persistent phenotype. Such a scenario seems to occur in tetracycline-resistant porcine C. trachomatis strains, which produced large aberrant RB in response to the antibiotic at 2 g/ml (66). Could the gyrA mutations that developed in cell culture in response to fluoroquinolone exposure (29) also favor the formation of a persistent phenotype, since alterations to DNA gyrase could inhibit RB-to-EB differentiation?…”

Emancipating Chlamydia: Advances in the Genetic Manipulation of a Recalcitrant Intracellular Pathogen

“…Furthermore, the higher MICs required for the delivery of these antibiotics into the inclusion can lead to toxicity in the host cell, which imposes further limits on the use of antibiotics for selection. Several antibiotics have been used successfully in genetic selections, including chloramphenicol, kasugamycin, nalidixic acid, rifampin, spectinomycin, trimethoprim, tetracycline (only for naturally resistant veterinary strains), ␤-lactams (only for LGV serovars), and blasticidin S (12,14,18,19,27,31,(50)(51)(52)(53). However, the use of mutant versions of chlamydial factors, such as 16S rRNA, RpoB, and GyrA, that render them resistant to antibiotics as selectable markers is limited because the gene mutations that confer resistance to these antibiotics are often recessive.…”