Publications

emended description of the order chlamydiales, proposal of parachlamydiaceae fam. nov. and simkaniaceae fam. nov., each containing one monotypic genus, revised taxonomy of the family chlamydiaceae, including a new genus and five new species, and standards for the identification of organisms.	the current taxonomic classification of chlamydia is based on limited phenotypic, morphologic and genetic criteria. this classification does not take into account recent analysis of the ribosomal operon or recently identified obligately intracellular organisms that have a chlamydia-like developmental cycle of replication. neither does it provide a systematic rationale for identifying new strains. in this study, phylogenetic analyses of the 16s and 23s rrna genes are presented with corroborating ...	1999	10319462
characterization of the rnpb gene and rnase p rna in the order chlamydiales.	the sequence of the rnase p rna gene (rnpb) was determined for 60 strains representing all nine species in the family chlamydiaceae and for the related chlamydiales species, parachlamydia acanthamoebae and simkania negevensis. these sequences were used to infer evolutionary relationships among the chlamydiaceae. the analysis separated chlamydophila and chlamydia into two lineages, with chlamydophila forming three distinct clusters: the chlamydophila pneumoniae strains; the chlamydophila pecorum ...	2000	10826799
peptide immunization of guinea pigs against chlamydia psittaci (gpic agent) infection induces good vaginal secretion antibody response, in vitro neutralization and partial protection against live challenge.	immunization of female guinea pigs with a chimeric peptide consisting of variable domain iv (vdiv) and a region known as gp8 from the major outer membrane protein of chlamydophila caviae, formerly chlamydia psittaci guinea pig inclusion conjunctivitis strain, was performed to assess whether humoral immune responses could be elicited in the reproductive tracts of immunized animals. the c. caviae strain is able to cause a sexually transmitted infection in the guinea pig that closely parallels c. t ...	2001	11380677
genome sequence of chlamydophila caviae (chlamydia psittaci gpic): examining the role of niche-specific genes in the evolution of the chlamydiaceae.	the genome of chlamydophila caviae (formerly chlamydia psittaci, gpic isolate) (1 173 390 nt with a plasmid of 7966 nt) was determined, representing the fourth species with a complete genome sequence from the chlamydiaceae family of obligate intracellular bacterial pathogens. of 1009 annotated genes, 798 were conserved in all three other completed chlamydiaceae genomes. the c.caviae genome contains 68 genes that lack orthologs in any other completed chlamydial genomes, including tryptophan and t ...	2003	12682364
conservation of the biochemical properties of inca from chlamydia trachomatis and chlamydia caviae: oligomerization of inca mediates interaction between facing membranes.	the developmental cycle of chlamydiaceae occurs in a membrane compartment called an inclusion. inca is a member of a family of proteins synthesized and secreted onto the inclusion membrane by bacteria. inca proteins from different species of chlamydiaceae show little sequence similarity. we report that the biochemical properties of chlamydia trachomatis and chlamydia caviae are conserved. both proteins self-associate to form multimers. when artificially expressed by the host cell, they localize ...	2004	15316015
analysis of chlamydia caviae entry sites and involvement of cdc42 and rac activity.	in epithelial cells, endocytic activity is mostly dedicated to nutrient and macromolecule uptake. to invade these cells, chlamydiaceae, like other pathogens, have evolved strategies that utilise the existing endocytic machineries and signalling pathways, but little is known about the host cell molecules involved. in this report, we show that within five minutes of infection of hela cells by chlamydia caviae gpic strain several events take place in the immediate vicinity of invasive bacteria: gm1 ...	2004	15265988
chlamydial development is blocked in host cells transfected with chlamydophila caviae inca.	chlamydiae produce a set of proteins, termed inc proteins, that are localized to the inclusion membrane and exposed to the host cell cytosol. little information exists regarding the interaction of inc proteins with the eukaryotic cell. to examine these interactions, vaccinia virus vectors and mammalian plasmid-based systems were used to express inc genes in mammalian cells.	2004	15230981
screening a wide host-range, waste-water metagenomic library in tryptophan auxotrophs of rhizobium leguminosarum and of escherichia coli reveals different classes of cloned trp genes.	a metagenomic cosmid library was constructed, in which the insert dna was derived from bacteria in a waste-water treatment plant and the vector was the wide host-range cosmid plafr3. the library was screened for clones that could correct defined tryptophan auxotrophs of the alpha-proteobacterium rhizobium leguminosarum and of escherichia coli. a total of 26 different cosmids that corrected at least one trp mutant in one or both of these species were obtained. several cosmids corrected the auxotr ...	2005	16309391
the chlamydophila abortus genome sequence reveals an array of variable proteins that contribute to interspecies variation.	the obligate intracellular bacterial pathogen chlamydophila abortus strain s26/3 (formerly the abortion subtype of chlamydia psittaci) is an important cause of late gestation abortions in ruminants and pigs. furthermore, although relatively rare, zoonotic infection can result in acute illness and miscarriage in pregnant women. the complete genome sequence was determined and shows a high level of conservation in both sequence and overall gene content in comparison to other chlamydiaceae. the 1,14 ...	2005	15837807
production of a proteolytically active protein, chlamydial protease/proteasome-like activity factor, by five different chlamydia species.	we have previously identified a chlamydial protein, chlamydial protease/proteasome-like activity factor (cpaf), for degrading host transcription factors in cells infected with the human chlamydial species chlamydia trachomatis or chlamydia pneumoniae. we now report that functional cpaf was also produced during infection with the species chlamydia muridarum, chlamydia psittaci, and chlamydia caviae, which primarily infect nonhuman hosts.	2005	15731091
conjunctival swab cytology from a guinea pig: it's elementary!	three 3-month-old guinea pigs (cavia porcellus) were evaluated for purulent ocular discharge. conjunctival swabs were obtained for cytologic evaluation of wright's-giemsa-stained preparations. the specimen from the most severely affected guinea pig consisted primarily of karyolytic neutrophils and small lymphocytes. epithelial cells occasionally were observed that contained intracytoplasmic coccoid basophilic organisms, 0.5-1.5 microm in diameter. the intraepithelial inclusions were most consist ...	2005	15902672
tyrosine phosphorylation of the chlamydial effector protein tarp is species specific and not required for recruitment of actin.	chlamydiae are obligate intracellular pathogens that efficiently induce their endocytosis by susceptible eukaryotic host cells. recently, a chlamydia trachomatis type iii secreted effector protein, tarp, was found to be translocated and tyrosine phosphorylated at the site of entry and associated with the recruitment of actin that coincides with endocytosis. c. trachomatis tarp possesses up to six direct repeats of approximately 50 amino acids each. the majority of the tyrosine residues are found ...	2005	15972471
chlamydiales in guinea-pigs and their zoonotic potential.	the aim was to detect and characterize chlamydial infections in guinea-pigs (gp) with ocular disease, study their pathogenicity and zoonotic potential and to test for the presence of acanthamoebae spp. in gp eyes and to investigate whether they could act as vectors for chlamydia-like organisms. overall 126 gp, of which 77 were symptomatic, were screened by clinical examination, cytology, gross pathology, histology, immunohistochemistry, polymerase chain reaction (pcr) and bacteriology. a new chl ...	2006	16629952
arginine-dependent gene regulation via the argr repressor is species specific in chlamydia.	some, but not all, chlamydia spp. are predicted to encode a homolog of argr, a master regulatory molecule that modulates arginine biosynthesis and catabolism in bacteria in response to intracellular arginine levels. while genes for arginine biosynthesis are apparently missing in chlamydia, a putative arginine transport system encoded by glnp, glnq, and artj is present. we found that recombinant chlamydia pneumoniae argr functions as an arginine-dependent aporepressor that bound specifically to o ...	2006	16428395
the chlamydial invasin-like protein gene conundrum.	variants of an ilp (invasin-like protein) gene have been identified previously in chlamydia caviae and in chlamydia suis. the c. caviae ilp gene is interrupted by two frame shift mutations while the c. suis gene is intact. characterization of the ilp gene in c. caviae passaged minimally in vitro showed that the two frameshift mutations were present in the original isolates. the gentamicin protection assay was used to determine if e. coli bacteria expressing the intact c. suis ilp could adhere to ...	2007	17533147
host alpha-adducin is redistributed and localized to the inclusion membrane in chlamydia- and chlamydophila-infected cells.	a large-scale analysis of proteins involved in host-cell signalling pathways was performed using chlamydia-infected murine cells in order to identify host proteins that are differentially activated or localized following infection. two proteins whose distribution was altered in chlamydia trachomatis-infected cells relative to mock-infected cells were the actin-binding protein adducin and the regulatory kinase raf-1. immunoblot analysis with antibodies to both phosphorylated and non-phosphorylate ...	2008	19047752
phylogenetic comparison of the known chlamydia trachomatis sigma(66) promoters across to chlamydia pneumoniae and chlamydia caviae identifies seven poorly conserved promoters.	we used four different phylogenetic footprinting programs and the six chlamydial species with publicly available whole genome sequences to analyze the 12 known sigma(66) promoters of chlamydia trachomatis that phylogenetically footprinted negative in our previous paper. the analysis showed that 7 of the 12 promoters were poorly conserved across c. trachomatis, chlamydia pneumoniae and chlamydia caviae. interestingly, the associated gene sets for these seven promoters were homologs and the gene o ...	2008	18708139
chlamydiae and polymorphonuclear leukocytes: unlikely allies in the spread of chlamydial infection.	while much is known about the attachment of the chlamydiae to the host cell and intracellular events during the developmental cycle, little is known about the mechanism(s) by which elementary bodies exit the cell. in this report, we use the guinea-pig conjunctival model of chlamydia caviae infection to present in vivo ultrastructural evidence supporting two mechanisms for release of chlamydiae from the mucosal epithelia. four days after infection, histopathologic observation shows an intense inf ...	2008	18657107
effect of chlamydiaphage phicpg1 on the course of conjunctival infection with "chlamydia caviae" in guinea pigs.	over the last several years, four different phages of chlamydiae, in addition to a phage associated with chlamydia psittaci isolated from an ornithosis infection in ducks over 25 years ago, have been described and characterized. while these phages and their chlamydial host specificities have been characterized in vitro, there is virtually nothing known about the interaction of the phage with chlamydiae in their natural animal host. phicpg1 is a lytic phage specific for "chlamydia caviae," which ...	2009	19139194
ocular pathologic response elicited by chlamydia organisms and the predictive value of quantitative modeling.	chlamydia organisms are a significant cause of ocular and genital tract disease worldwide. acute inflammatory responses are largely responsible for pathologic changes.	2009	19419335
comprehensive in silico prediction and analysis of chlamydial outer membrane proteins reflects evolution and life style of the chlamydiae.	chlamydiae are obligate intracellular bacteria comprising some of the most important bacterial pathogens of animals and humans. although chlamydial outer membrane proteins play a key role for attachment to and entry into host cells, only few have been described so far. we developed a comprehensive, multiphasic in silico approach, including the calculation of clusters of orthologues, to predict outer membrane proteins using conservative criteria. we tested this approach using escherichia coli (po ...	2009	20040079
horizontal transfer of tetracycline resistance among chlamydia spp. in vitro.	there are no examples of stable tetracycline resistance in clinical strains of chlamydia trachomatis. however, the swine pathogen chlamydia suis is commonly tetracycline resistant, both in america and in europe. in tested u.s. strains, this resistance is mediated by a genomic island carrying a tet(c) allele. in the present study, the ability of c. suis to mobilize tet(c) into other chlamydial species was examined. differently antibiotic resistant strains of c. suis, c. trachomatis, and chlamydia ...	2009	19687238
epidemiology of chlamydophila caviae-like chlamydia isolated from urethra and uterine cervix.	in 2000, chlamydial strains ok133 and ok135 were isolated from 2 female patients with cervicitis. these strains were unresponsive to commercially available pcr and lcr test kits for the diagnosis of chlamydia trachomatis infection, and their phenotypic characteristics were very similar. the ok135 nucleotide sequence in momp-vd2 gene closely resembled that of chlamydophila caviae gpic. a similar strain was isolated in 2003 from a male patient okm2 with urethritis, from which the strain sc10-6 was ...	2010	20200578
detection of chlamydophila caviae and streptococcus equi subsp. zooepidemicus in horses with signs of rhinitis and conjunctivitis.	at a stud farm of trakehner horses, all 33 foals of a birth cohort developed conjunctivitis and serous to muco-purulent rhinitis, and 7 older horses showed recurrent signs of conjunctivitis. examination of nasal and conjunctival swabs by bacterial and cell culture, as well as real-time pcr, arraytube microarray analysis and dna sequencing led to the identification of chlamydophila (c.) caviae (first description in horses) and streptococcus (s.) equi subsp. zooepidemicus. we presume a synergistic ...	2010	19913370
impact of azithromycin resistance mutations on the virulence and fitness of chlamydia caviae in guinea pigs.	azithromycin (azm) is a major drug used in the treatment and prophylaxis of infections caused by chlamydia, yet no significant clinical resistance has been reported for these obligate intracellular bacteria. nevertheless, spontaneous azm resistance (azm(r)) arose in vitro at frequencies ranging from 3 x 10(-8) to 8 x 10(-10) for clonal isolates of chlamydia caviae, which is a natural pathogen of guinea pigs. sequencing of the unique 23s rrna gene copy in 44 independent azm(r) isolates identified ...	2010	20065052
local host response to chlamydial urethral infection in male guinea pigs.	very little is known about the host response to chlamydial genital infection in the male, particularly about the nature of the local response in the urethra. in this study, the pathological and immunologic responses to urethral infection of the male guinea pig with chlamydia caviae (chlamydophila caviae) were characterized both during a primary infection and following a challenge infection. a dose-response experiment found that the 50% infectious dose for male urethral infection was 78 inclusion ...	2010	20123720
essential role for neutrophils in pathogenesis and adaptive immunity in chlamydia caviae ocular infections.	trachoma, the world's leading cause of preventable blindness, is produced by chronic ocular infection with chlamydia trachomatis, an obligate intracellular bacterium. while many studies have focused on immune mechanisms for trachoma during chronic stages of infection, less research has targeted immune mechanisms in primary ocular infections, events that could impact chronic responses. the goal of this study was to investigate the function of neutrophils during primary chlamydial ocular infection ...	2011	21402767
role for the src family kinase fyn in sphingolipid acquisition by chlamydiae.	the bacterial obligate intracellular pathogen chlamydia trachomatis replicates within a membrane-bound vacuole termed the inclusion. from within this protective environment, chlamydiae usurp numerous functions of the host cell to promote chlamydial survival and replication. here we utilized a small interfering rna (sirna)-based screening protocol designed to identify host proteins involved in the trafficking of sphingomyelin to the chlamydial inclusion. twenty-six host proteins whose deficiency ...	2011	21896774
partial protection against chlamydial reproductive tract infection by a recombinant major outer membrane protein/cpg/cholera toxin intranasal vaccine in the guinea pig chlamydia caviae model.	chlamydia trachomatis is a major cause of sexually transmitted diseases worldwide. there is currently no vaccine to protect against chlamydial infection of the female reproductive tract. vaccine development has predominantly utilised the murine model; however, infection of female guinea pigs with chlamydia caviae more closely resembles chlamydial infection of the human female reproductive tract, and presents a better model to assess potential human chlamydial vaccines. we immunised female guinea ...	2011	21856018
effect of inflammatory response on in vivo competition between two chlamydial variants in the guinea pig model of inclusion conjunctivitis.	in order to study the interaction of variants in in vivo infection, we employed an azithromycin-resistant mutant (az(2)) and its wild-type parent (sp(6)) in the guinea pig model of chlamydia caviae conjunctival infection. when each strain was inoculated individually into conjunctiva, both attained the same level of growth, but az(2) elicited less pathology. however, when equal numbers of the two strains were inoculated together into the guinea pig conjunctiva, sp(6) produced a significantly grea ...	2011	22144478
identification, sequencing and molecular analysis of chp4, a novel chlamydiaphage of chlamydophila abortus belonging to the family microviridae.	members of the family microviridae have been identified in a number of chlamydial species infecting humans (phage cpar39 in chlamydophila pneumoniae), other mammals (fcpg1 in chlamydophila caviae, chp2 in chlamydophila abortus and chp3 in chlamydophila pecorum) and birds (chp1 in chlamydophila psittaci). this study describes the identification and genome sequencing of chp4, an icosahedral, 4530 bp, ssdna phage in c. abortus. chp4 is predicted to contain eight orfs, six of which could be assigned ...	2011	21450942
resistance to a novel antichlamydial compound is mediated through mutations in chlamydia trachomatis secy.	a novel and quantitative high-throughput screening approach was explored as a tool for the identification of novel compounds that inhibit chlamydial growth in mammalian cells. the assay is based on accumulation of a fluorescent marker by intracellular chlamydiae. its utility was demonstrated by screening 42,000 chemically defined compounds against chlamydia caviae gpic. this analysis led to the identification of 40 primary-hit compounds. five of these compounds were nontoxic to host cells and ha ...	2012	22644029
characterization of the activity and expression of arginine decarboxylase in human and animal chlamydia pathogens.	chlamydia pneumoniae encodes a functional arginine decarboxylase (argdc), aaxb, that activates upon self-cleavage and converts l-arginine to agmatine. in contrast, most chlamydia trachomatis serovars carry a missense or nonsense mutation in aaxb abrogating activity. the g115r missense mutation was not predicted to impact aaxb functionality, making it unclear whether aaxb variations in other chlamydia species also result in enzyme inactivation. to address the impact of gene polymorphism on functi ...	2012	23043454
plasmid-cured chlamydia caviae activates tlr2-dependent signaling and retains virulence in the guinea pig model of genital tract infection.	loss of the conserved "cryptic" plasmid from c. trachomatis and c. muridarum is pleiotropic, resulting in reduced innate inflammatory activation via tlr2, glycogen accumulation and infectivity. the more genetically distant c. caviae gpic is a natural pathogen of guinea pigs and induces upper genital tract pathology when inoculated intravaginally, modeling human disease. to examine the contribution of pcpgp1 to c. caviae pathogenesis, a cured derivative of gpic, strain cc13, was derived and evalu ...	2012	22292031
the chlamydial otu domain-containing protein chlaotu is an early type iii secretion effector targeting ubiquitin and ndp52.	chlamydia are obligate intracellular pathogens. upon contact with the host, they use type iii secretion to deliver proteins into the cell, thereby triggering actin-dependent entry and establishing the infection. we observed that chlamydia caviae elicited a local and transient accumulation of ubiquitinated proteins at the entry sites, which disappeared within 20 min. we investigated the mechanism for the rapid clearance of ubiquitin. we showed that the otu-like domain containing protein cca00261, ...	2013	23869922
use of a guinea pig-specific transcriptome array for evaluation of protective immunity against genital chlamydial infection following intranasal vaccination in guinea pigs.	guinea pigs have been used as a second animal model to validate putative anti-chlamydial vaccine candidates tested in mice. however, the lack of guinea pig-specific reagents has limited the utility of this animal model in chlamydia sp. vaccine studies. using a novel guinea pig-specific transcriptome array, we determined correlates of protection in guinea pigs vaccinated with chlamydia caviae (c. caviae) via the intranasal route, previously reported by us and others to provide robust antigen spec ...	2014	25502875
the chlamydia effector tarp mimics the mammalian leucine-aspartic acid motif of paxillin to subvert the focal adhesion kinase during invasion.	host cell signal transduction pathways are often targets of bacterial pathogens, especially during the process of invasion when robust actin remodeling is required. we demonstrate that the host cell focal adhesion kinase (fak) was necessary for the invasion by the obligate intracellular pathogen chlamydia caviae. bacterial adhesion triggered the transient recruitment of fak to the plasma membrane to mediate a cdc42- and arp2/3-dependent actin assembly. fak recruitment was via binding to a domain ...	2014	25193659
chlamydial variants differ in ability to ascend the genital tract in the guinea pig model of chlamydial genital infection.	an important question in the study of chlamydial genital tract disease is why some women develop severe upper tract disease while others have mild or even "silent" infections with or without pathology. animal studies suggest that the pathological outcome of an infection is dependent upon both the composition of the infecting chlamydial population and the genotype of the host, along with host physiological effects, such as the cyclical production of reproductive hormones and even the size of the ...	2015	26015484
emendation of the family chlamydiaceae: proposal of a single genus, chlamydia, to include all currently recognized species.	the family chlamydiaceae (order chlamydiales, phylum chlamydiae) comprises important, obligate intracellular bacterial pathogens of humans and animals. subdivision of the family into the two genera chlamydia and chlamydophila has been discussed controversially during the past decade. here, we have revisited the current classification in the light of recent genomic data and in the context of the unique biological properties of these microorganisms. we conclude that neither generally used 16s rrna ...	2015	25618261
chlamydia caviae infection alters abundance but not composition of the guinea pig vaginal microbiota.	in humans, the vaginal microbiota is thought to be the first line of defense again pathogens including chlamydia trachomatis. the guinea pig has been extensively used as a model to study chlamydial infection because it shares anatomical and physiological similarities with humans, such as a squamous vaginal epithelium as well as some of the long-term outcomes caused by chlamydial infection. in this study, we aimed to evaluate the guinea pig-c. caviae model of genital infection as a surrogate for ...	2015	25761873
phosphoproteomic analysis of the chlamydia caviae elementary body and reticulate body forms.	chlamydia are gram-negative, obligate intracellular bacteria responsible for significant diseases in humans and economically important domestic animals. these pathogens undergo a unique biphasic developmental cycle transitioning between the environmentally stable elementary body (eb) and the replicative intracellular reticulate body (rb), a conversion that appears to require extensive regulation of protein synthesis and function. however, chlamydia possess a limited number of canonical mechanism ...	2015	25998263
chlamydiaphage φcpg1 capsid protein vp1 inhibits chlamydia trachomatis growth via the mitogen-activated protein kinase pathway.	chlamydia trachomatis is the most common cause of curable bacterial sexually transmitted infections worldwide. although the pathogen is well established, the pathogenic mechanisms remain unclear. given the current challenges of antibiotic resistance and blocked processes of vaccine development, the use of a specific chlamydiaphage may be a new treatment solution. φcpg1 is a lytic phage specific for chlamydia caviae, and shows over 90% nucleotide sequence identity with other chlamydiaphages. vp1 ...	2016	27089359
the presence of chlamydia phage phicpg1 capsid protein vp1 genes and antibodies in patients infected with chlamydia trachomatis.	chlamydia phage phicpg1 has been found in chlamydia caviae in a guinea pig model for inclusion conjunctivitis, raising the possibility that chlamydia phage is also present in patients infected with c. trachomatis (ct). in the present study, we assayed for presence of chlamydia phage capsid protein vp1 genes and antibodies in 84 non-ct controls and 206 ct patients using an enzyme-linked immunoassay (elisa), followed by verification with western blot. none of the subjects were exposed to an antibi ...	2016	27213552
infectious dose and repeated infections are key factors influencing immune response characteristics in guinea pig ocular chlamydial infection.	the aim of this study was to determine whether infectious dose of chlamydia caviae after repeated infections influences the immunological responses and subsequent clearance of pathogen at the ocular surface of guinea pigs. animals were infected three times via the conjunctiva at six- and twelve-week intervals by applying either 1 × 10(4) or 1 × 10(6) inclusion-forming units (ifus) of c. caviae. ocular pathology, infection course, c. caviae-specific serum igg levels and their capacity to bind and ...	2016	26706818
the effect of infectious dose on humoral and cellular immune responses in chlamydophila caviae primary ocular infection.	following infection, the balance between protective immunity and immunopathology often depends on the initial infectious load. several studies have investigated the effect of infectious dose; however, the mechanism by which infectious dose affects disease outcomes and the development of a protective immune response is not known. the aim of this study was to investigate how the infectious dose modulates the local and systemic humoral and the cellular immune responses during primary ocular chlamyd ...	2017	28678871