Search

Chlamydia pecorum, an obligate intracellular bacterium, is associated with reproductive and systemic diseases in sheep, goats, pigs, cattle, and koalas. The main conditions include polyarthritis, conjunctivitis, enteritis, pneumonia, encephalomyelitis, orchitis, placentitis, and abortion. Even though there are several studies showing that C. pecorum infections are widely spread in the world, in Mexico there are no reports. During 2016, as part of a sheep restocking program in Mexico, sheep were imported from New Zealand. Briefly after their arrival in the herds in the State of Mexico, these sheep presented abortions during the last third of gestation. A total of 62 sheep vaginal swabs that had presented abortion from different municipalities of the State of Mexico were collected. Bacterial isolation was performed using L929 mouse fibroblasts, and molecular identification was achieved by 23S rRNA (Chlamydiaceae family) and ompA gene (species-specific) real-time polymerase chain reaction (PCR). In addition, the 16S rRNA subunit and ompA gene were amplified and sequenced. Seven of 62 samples were positive for C. pecorum by bacterial isolation, 23S rRNA, and ompA gene real-time PCR. The 16S rRNA subunit and ompA gene amplicons were purified and the nucleotide sequence was determined in both directions. The consensus sequences homology search was performed using BLASTn analysis and showed a 100% of homology with the C. pecorum 16S rRNA subunit and 99% with the C. pecorum ompA gene. The population structure analyses using ompA gene demonstrated 15 genetic populations or clusters of 198 sequences from GenBank and our sequences were in a particular genetic structure corresponding to genotype “O.” Herein, we describe the presence of C. pecorum in sheep imported from New Zealand into Mexico. Genetic analysis of the ompA gene showed that the isolates belong to genotype O and are related to strains isolated from sheep, cattle, and koalas. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s42770-022-00682-9.

This study explored factors associated with interest in taking PrEP among men who have sex with men (MSM) attending HIV testing venues in Sweden. Data from 658 HIV-negative respondents, surveyed by a questionnaire at six sites, were analyzed descriptively and by univariable and multivariable logistic regression. A total of 453 (68.8%) of the respondents expressed interest in taking PrEP. Reporting self-perceived risk of HIV acquisition as moderate or high, reporting ≥ 5 partners for condomless anal intercourse during the past year, and reporting hard drug use during the past year were independently associated with interest in taking PrEP. However, an aggregated variable of self-reported rectal gonorrhea, rectal chlamydia, or syphilis infection during the past year was not associated with interest in taking PrEP. Overall, Swedish MSM were well-informed regarding PrEP, and interest in taking PrEP was positively associated with sexual risk indicators.

Chlamydia is an obligate intracellular bacterial pathogen that replicates solely within a membrane-bound vacuole termed an inclusion. Chlamydia seems to perturb multiple cellular processes of the host, such as, rearrangement of the membrane trafficking system for its intracellular multiplication, and inhibition of host cell apoptosis for persistent infection. In an attempt to clarify host factor involvement in apoptosis regulation, we found that inhibition of Caspase-9 restricted, while Apaf-1 promoted, Chlamydia pneumoniae infection in HEp-2, HeLa, and mouse epithelial fibroblast (MEF) cells. These opposition contributions to the chlamydial infection were confirmed using caspase-9 (-/-) and apaf-1 (-/-) MEFs. Similar phenomena also appeared in the case of infection with Chlamydia trachomatis. Interestingly, caspase-9 in apaf-1 (-/-) MEFs was activated by chlamydial infection but during the infection caspase-3 was not activated. That is, caspase-9 was activated without support for multiplication and activation by Apaf-1, and the activated caspase-9 may be physically disconnected from the caspase cascade. This may be partially explained by the observation of caspase-9 accumulation within chlamydial inclusions. The sequestration of caspase-9 by chlamydia seems to result in apoptosis repression, which is crucial for the chlamydial development cycle. Because Apaf-1 shares domains with intracellular innate immune receptor NOD1, it may play a key role in the strategy to regulate chlamydial infection.

There is a dearth of evidence on injection drug use and associated HIV infections in Kenya. To generate population-based estimates of characteristics and HIV/STI prevalence among people who inject drugs (PWID) in Nairobi, a cross-sectional study was conducted with 269 PWID using respondent-driven sampling. PWID were predominantly male (92.5 %). An estimated 67.3 % engaged in at least one risky injection practice in a typical month. HIV prevalence was 18.7 % (95 % CI 12.3–26.7), while STI prevalence was lower [syphilis: 1.7 % (95 % CI 0.2–6.0); gonorrhea: 1.5 % (95 % CI 0.1–4.9); and Chlamydia: 4.2 % (95 % CI 1.2–7.8)]. HIV infection was associated with being female (aOR, 3.5; p = 0.048), having first injected drugs 5 or more years ago (aOR, 4.3; p = 0.002), and ever having practiced receptive syringe sharing (aOR, 6.2; p = 0.001). Comprehensive harm reduction programs tailored toward PWID and their sex partners must be fully implemented as part of Kenya’s national HIV prevention strategy.

Chlamydia pneumoniae, Mycoplasma pneumoniae, and Legionella spp. are common causes of atypical pneumonia; however, data about these atypical pathogens are limited in the refugee setting. Paired nasopharyngeal and oropharyngeal specimens were collected from patients with respiratory illness presenting to healthcare centers in two refugee camps in Kenya. The specimens were tested for C. pneumoniae, M. pneumoniae, and Legionella spp. as well as eight respiratory viruses. Atypical pathogens were detected in 5.5% of the specimens of which 54% were co-infected with at least one of the eight viruses tested. Patients positive for atypical bacteria co-infected with virus were significantly more likely to have severe acute respiratory illness than patients infected with only atypical bacteria (P = 0.04). While the percentage of atypical pathogens identified was lower than expected, we found a significant relationship between atypical bacterial-viral co-infection and severity of disease in this refugee population.

Autoimmunity to heat shock protein 60 (HSP60) has been related to atherosclerosis. Chlamydia pneumoniae (CP), the most studied infectious agent implicated in promoting atherosclerosis, produces a form of HSP60, which can induce an autoimmune response, due to high antigenic homology with human HSP60 (hHSP60). In this study, we evaluated the correlations among anti-hHSP60 antibodies, CP infection, and cardiovascular disease (CVD) in a high-risk population, such as patients undergoing hemodialysis (HD). Thirty-two patients (67.9 ± 13.9 years; male/female, 23:9) on regular HD were enrolled. Global absolute cardiovascular risk (GCR) was assessed using the Italian CUORE Project’s risk charts, which evaluate age, gender, smoking habits, diabetes, systolic blood pressure, and serum cholesterol. The occurrence of cardiovascular events during a 24-month follow-up was recorded. Seropositivity to CP and the presence of anti-hHSP60 antibodies were tested by specific enzyme-linked immunosorbent assays. Inflammation was assessed by measurement of C-reactive protein (CRP) serum levels. Fifteen healthy sex and age-matched (61.9 ± 9.5 years; male/female, 11:4) subjects were the control group. Fifteen of 32 patients resulted seropositive for CP. CP + patients were older than CP−, while they did not differ for GCR, CRP, and dialytic parameters. CVD incidence was significantly higher in CP+ (9 CP+ vs 2 CP−, p

Bacteria from the Chlamydiales order have been long known, especially as pathogenic bacteria to humans and many animal species, principally including birds and mammals. But for slightly over 20 years, they have been identified in the aquatic environment as endosymbionts of amoebas and sea worms. For several years, they have also been recorded as a cause of diseases among fish, causing respiratory system infections in the form of epitheliocystis of the gill. At present, 11 chlamydia-like organisms pathogenic to fish have been described, including nine new ones, classified into six families, four of which are already known (Parachlamydiaceae, Rhabdochlamydiaceae, Candidatus Parilichlamydiaceae, Candidatus Clavichlamydiaceae) and two newly created families, namely Candidatus Actinochlamydiaceae and Candidatus Parilichlamydiaceae. This paper characterises 11 chlamydia-like organisms, as well as seven isolates not classified into families, which are pathogenic to fish, presenting their genetical properties allowing for their classification, as well as morphological properties and diseases caused.

Using a hypersegregation framework, this paper examines the relationship between racial isolation (i.e., segregation) and chlamydia rates in counties of different racial compositions. A series of “race-of-county”-stratified regression models estimate chlamydia rates with black isolation and white isolation, net of (i.e., controlling for) region, college graduation rates, sex ratios, unemployment rates, median income, population density, and income inequality. The results show that in white counties, both black isolation and white isolation are associated with decreases in chlamydia rates. In integrated and disproportionately black counties, black isolation is associated with higher rates of chlamydia, but white isolation is associated with lower rates of chlamydia. These findings suggest that the relationship of residential segregation to chlamydia rates differs when it is due to white isolation versus black isolation, and the effects of black isolation within disproportionately black counties are not equivalent to black isolation in white counties because the levels of concentrated disadvantage are not similar.

In Germany, local health authorities (LHA) offering counseling and testing for sexually transmitted infections or human immunodeficiency virus (STI/HIV) routinely collect data. The study's objective was to get an overview of the activities and data collected by the LHA so as to investigate the possibility of harvesting these data at a national level. We performed a cross-sectional survey among all LHA with STI/HIV counseling and testing by using an electronic questionnaire with information on the type of STI/HIV services offered, groups reached, and data collected. Among the 374 LHA, 250 (67 %) responded. Half of them offered common counseling for STI and HIV; 20% conducted outreach work among sex workers and other groups. While HIV tests were available in all LHA, 62 and 56 % also offered hepatitis B and C testing, respectively. Other available tests included syphilis (56 %), gonorrhea (28 %), and chlamydia (27 %). Only 13 % of LHA offer gynecological examinations. While 98 % of LHA reported collecting data, two thirds of these records were paper-based. Although 77 % analyzed their data, 58 % reported their data to the regional level. Standardization of the STI/HIV data seems feasible for most of the LHA. This would allow annual statistics to be compiled at municipal, regional, and national levels.

The medically significant genus Chlamydia is a class of obligate intracellular bacterial pathogens that replicate within vacuoles in host eukaryotic cells termed inclusions. Chlamydia's developmental cycle involves two forms; an infectious extracellular form, known as an elementary body (EB), and a non-infectious form, known as the reticulate body (RB), that replicates inside the vacuoles of the host cells. The RB surface is covered in projections that are in intimate contact with the inclusion membrane. Late in the developmental cycle, these reticulate bodies differentiate into the elementary body form. In this paper, we present a hypothesis for the modulation of these developmental events involving the contact-dependent type III secretion (TTS) system. TTS surface projections mediate intimate contact between the RB and the inclusion membrane. Below a certain number of projections, detachment of the RB provides a signal for late differentiation of RB into EB. We use data and develop a mathematical model investigating this hypothesis. If the hypothesis proves to be accurate, then we have shown that increasing the number of inclusions per host cell will increase the number of infectious progeny EB until some optimal number of inclusions. For more inclusions than this optimum, the infectious yield is reduced because of spatial restrictions. We also predict that a reduction in the number of projections on the surface of the RB (and as early as possible during development) will significantly reduce the burst size of infectious EB particles. Many of the results predicted by the model can be tested experimentally and may lead to the identification of potential targets for drug design.

Background Chlamydia infection is the most common notifiable sexually transmitted infection (STI) in Australia and mostly affects young people (15 – 25 years). This paper presents baseline data from a randomised controlled trial that aimed to increase chlamydia testing among sexually active young people. The objectives were to identify associations between sexual behaviour, substance use and STI history and explore attitudes to chlamydia testing. Methods This study was conducted in cyberspace. Study recruitment, allocation, delivery of interventions and baseline and follow up data collection all took place online. Participants were 16 – 25 years old and resided in Australia. Substance use correlates of sexual activity; predictors of history of STIs; barriers to and facilitators of chlamydia testing were analysed. Results Of 856 participants (79.1% female), 704 had experienced penetrative intercourse. Sexually active participants were more likely to smoke regularly or daily, to drink alcohol, or to have binge drunk or used marijuana or other illicit substances recently. Risk factors for having a history of any STI were 3 or more sexual partners ever, 6 or more partners in the past 12 months, condom non-use and being 20 years or older. Almost all sexually active participants said that they would have a chlamydia test if their doctor recommended it. Conclusions Sexually active young people are at risk of STIs and may engage in substance use risk behaviours. Where one health risk behaviour is identified, it is important to seek information about others. Chlamydia testing can be facilitated by doctors and nurses recommending it. Primary care providers have a useful role in chlamydia control. Trial Registration Australian and New Zealand Trials Registry ACTRN12607000582459

Several studies have demonstrated an association Chlamydia pneumoniae with coronary artery disease, suggesting that infection with C. pneumoniae increases the risk for coronary artery disease by factor 2 or more. Since atherosclerosis is considered to be a chronic inflammatory process, these data would fit into the response-to-injury hypothesis of atherosclerosis rather than representing a completely novel concept. Several pathomechanisms as increased cytokine synthesis, proliferative and proaggregatory effects could transmit the effects of chronic C. pneumoniae infection. Animal models and first clinical trials using antibiotic therapy seem to support an etiological role of C. pneumoniae in coronary artery disease. In this paper the current knowledge of the role of C. pneumoniae in coronary artery disease is reviewed and possible pathomechanisms are discussed.

Background In many countries, low Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) screening rates among young people in primary-care have encouraged screening programs outside of clinics. Nucleic acid amplification tests (NAATs) make it possible to screen people in homes with self-collected specimens. We systematically reviewed the strategies and outcomes of home-based CT/NG screening programs. Methods Electronic databases were searched for home-based CT and/or NG screening studies published since January 2005. Screening information (e.g. target group, recruitment and specimen-collection method) and quantitative outcomes (e.g. number of participants, tests and positivity) were extracted. The screening programs were classified into seven groups on the basis of strategies used. Results We found 29 eligible papers describing 32 home-based screening programs. In seven outreach programs, people were approached in their homes: a median of 97% participants provided specimens and 76% were tested overall (13717 tests). In seven programs, people were invited to receive postal test-kits (PTKs) at their homes: a median of 37% accepted PTKs, 79% returned specimens and 19% were tested (46225 tests). PTKs were sent along with invitation letters in five programs: a median of 33% returned specimens and 29% of those invited were tested (15126 tests). PTKs were requested through the internet or phone without invitations in four programs and a median of 32% returned specimens (2666 tests). Four programs involved study personnel directly inviting people to receive PTKs: a median of 46% accepted PTKs, 21% returned specimens and 9.1% were tested (341 tests). PTKs were picked-up from designated locations in three programs: a total of 6765 kits were picked-up and 1167 (17%) specimens were returned for screening. Two programs used a combination of above strategies (2395 tests) but the outcomes were not reported separately. The overall median CT positivity was 3.6% (inter-quartile range: 1.7-7.3%). Conclusions A variety of strategies have been used in home-based CT/NG screening programs. The screening strategies and their feasibility in the local context need to be carefully considered to maximize the effectiveness of home-based screening programs.

Background Cohort studies are an important study design however they are difficult to implement, often suffer from poor retention, low participation and bias. The aims of this paper are to describe the methods used to recruit and retain young women in a longitudinal study and to explore factors associated with loss to follow up. Methods The Chlamydia Incidence and Re-infection Rates Study (CIRIS) was a longitudinal study of Australian women aged 16 to 25 years recruited from primary health care clinics. They were followed up via the post at three-monthly intervals and required to return questionnaires and self collected vaginal swabs for chlamydia testing. The protocol was designed to maximise retention in the study and included using recruiting staff independent of the clinic staff, recruiting in private, regular communication with study staff, making the follow up as straightforward as possible and providing incentives and small gifts to engender good will. Results The study recruited 66% of eligible women. Despite the nature of the study (sexual health) and the mobility of the women (35% moved address at least once), 79% of the women completed the final stage of the study after 12 months. Loss to follow up bias was associated with lower education level [adjusted hazard ratio (AHR): 0.7 (95% Confidence Interval (CI): 0.5, 1.0)], recruitment from a sexual health centre as opposed to a general practice clinic [AHR: 1.6 (95% CI: 1.0, 2.7)] and previously testing positive for chlamydia [AHR: 0.8 (95% CI: 0.5, 1.0)]. No other factors such as age, numbers of sexual partners were associated with loss to follow up. Conclusions The methods used were considered effective for recruiting and retaining women in the study. Further research is needed to improve participation from less well-educated women.

Background A selective, systematic, Internet-based, Chlamydia Screening Implementation for 16 to 29-year-old residents started in three regions in the Netherlands in April 2008: in the cities of Amsterdam and Rotterdam and a more rural region, South Limburg. This paper describes the evaluation design and discusses the implications of the findings from the first screening round for the analysis. The evaluation aims to determine the effects of screening on the population prevalence of Chlamydia trachomatis after multiple screening rounds. Methods A phased implementation or 'stepped wedge design' was applied by grouping neighbourhoods (hereafter: clusters) into three random, risk-stratified blocks (A, B and C) to allow for impact analyses over time and comparison of prevalences before and after one or two screening rounds. Repeated simulation of pre- and postscreening Chlamydia prevalences was used to predict the minimum detectable decline in prevalence. Real participation and positivity rates per region, block, and risk stratum (high, medium, and low community risk) from the 1st year of screening were used to substantiate predictions. Results The results of the 1st year show an overall participation rate of 16% of 261,025 invitees and a positivity rate of 4.2%, with significant differences between regions and blocks. Prediction by simulation methods adjusted with the first-round results indicate that the effect of screening (minimal detectable difference in prevalence) may reach significance levels only if at least a 15% decrease in the Chlamydia positivity rate in the cities and a 25% decrease in the rural region after screening can be reached, and pre- and postscreening differences between blocks need to be larger. Conclusions With the current participation rates, the minimal detectable decline of Chlamydia prevalence may reach our defined significance levels at the regional level after the second screening round, but will probably not be significant between blocks of the stepped wedge design. Evaluation will also include other aspects and prediction models to obtain rational advice about future Chlamydia screening in the Netherlands.

Background A national chlamydia screening programme is currently being rolled out in the UK and other countries. However, much of the epidemiology remains poorly understood. In this paper we present a stochastic, individual based, dynamic sexual network model of chlamydia transmission and its parameterisation. Mathematical models provide a theoretical framework for understanding the key epidemiological features of chlamydia: sexual behaviour, health care seeking and transmission dynamics. Results The model parameters were estimated either directly or by systematic fitting to a variety of appropriate data sources. The fitted model was representative of sexual behaviour, chlamydia epidemiology and health care use in England. We were able to recapture the observed age distribution of chlamydia prevalence. Conclusion Estimating parameters for models of sexual behaviour and transmission of chlamydia is complex. Most of the parameter values are highly correlated, highly variable and there is little empirical evidence to inform estimates. We used a novel approach to estimate the rate of active treatment seeking, by combining data sources, which improved the credibility of the model results. The model structure is flexible and is broadly applicable to other developed world settings and provides a practical tool for public health decision makers.

Two new papers look at different ways in which Chlamydia trachomatis interacts with the host cell cytoskeleton.