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

Abstract

Many strains of Chlamydia suis, a pathogen of pigs, express a stable tetracycline resistance phenotype. We demonstrate that this resistance pattern is associated with a resistance gene, tet(C), in the chlamydial chromosome. Four related genomic islands were identified in seven tetracycline-resistant C. suis strains. All resistant isolates carry the structural gene tet(C) and the tetracycline repressor gene tetR(C). The islands share significant nucleotide sequence identity with resistance plasmids carried by a variety of different bacterial species. Three of the four tet(C) islands also carry a novel insertion sequence that is homologous to the IS605 family of insertion sequences. In each strain, the resistance gene and associated sequences are recombined into an identical position in a gene homologous to the inv gene of the yersiniae. These genomic islands represent the first examples of horizontally acquired DNA integrated into a natural isolate of chlamydiae or within any other obligate intracellular bacterium.

Water-filtered infrared A reduces chlamydial infectivity in vitro without causing ex vivo eye damage in pig and mouse models

“…Of particular interest is the emergence of tetracycline resistance in C. suis, a growing problem in the pig rearing industry and probably the result of excessive tetracycline use for therapeutic purposes and as growth promoters in livestock since the 1950s (7)(8)(9)(10)(11). C. suis is primarily known to inapparently infect the porcine gastrointestinal tract with a prevalence of up to 90 % in fattening pigs (12).…”

The contribution of temperature, exposure intensity and visible light to the inhibitory effect of irradiation on acute chlamydial infection

“…The treatment of choice 26 for chlamydial infection is antimicrobial therapy; however, in general, the emergence of antibiotic-27 resistant bacteria raises concerns about the continued efficacy of this approach. Tetracycline-resistant 28 C. suis strains, harboring the tetC resistance gene, have been isolated from asymptomatic pigs in the 29 USA [13][14]. Horizontal transfer of this gene to various Chlamydia ssp.…”

“…Another study recently demonstrated that 11 wIRA/VIS reduced the inclusion frequency of acute chlamydial infection without adversely affecting the 12 cell viability or inducing cytotoxicity in host cells [6]. 13 The Chlamydiaceae are a family of gram-negative bacteria consisting of one genus designated 14…”

Tetracycline-resistant Chlamydia suis in cases of reproductive failure on Belgian, Cypriote and Israeli pig production farms

“…However, tetracycline-resistant C. suis strains have been isolated on swine farms in Iowa, Nebraska, Italy and Switzerland (Andersen & Rogers, 1998;Di Francesco et al, 2008). The C. suis tetracyclineresistant phenotype (Tc R ) is manifested through the tetracycline-resistance gene tet(C), which is integrated into the chlamydial chromosome (Dugan et al, 2004). More recently, Borel et al (2012) described the occurrence of C. suis in a Swiss pig farm with an outbreak of conjunctivitis and diarrhoea.…”