Emerging role of Chlamydia and Chlamydia-like organisms in adverse pregnancy outcomes

Parachlamydia acanthamoebae, an emerging agent of pneumonia

Parachlamydia acanthamoebae is a Chlamydia-like organism that easily grows within Acanthamoeba spp. Thus, it probably uses these widespread free-living amoebae as a replicative niche, a cosmopolite aquatic reservoir and a vector. A potential role of P. acanthamoebae as an agent of lower respiratory tract infection was initially suggested by its isolation within an Acanthamoeba sp. recovered from the water of a humidifier during the investigation of an outbreak of fever. Additional serological and molecular-based investigations further supported its pathogenic role, mainly in bronchiolitis, bronchitis, aspiration pneumonia and community-acquired pneumonia. P. acanthamoebae was shown to survive and replicate within human macrophages, lung fibroblasts and pneumocytes. Moreover, this strict intracellular bacterium also causes severe pneumonia in experimentally infected mice, thus fulfilling the third and fourth Koch criteria for a pathogenic role. Consequently, new tools have been developed for the diagnosis of parachlamydial infections. It will be important to routinely search for this emerging agent of pneumonia, as P. acanthamoebae is apparently resistant to quinolones, which are antibiotics often used for the empirical treatment of atypical pneumonia. Other Chlamydia-related bacteria, including Protochlamydia naegleriophila, Simkania negevensis and Waddlia chondrophila, might also cause lung infections. Moreover, several additional novel chlamydiae, e.g. Criblamydia sequanensis and Rhabdochlamydia crassificans, have been discovered and are now being investigated for their human pathogenicity.

Chlamydia trachomatis infection modulates trophoblast cytokine/chemokine production

It is well established that intrauterine infections can pose a threat to pregnancy by gaining access to the placenta and fetus, and clinical studies have strongly linked bacterial infections with preterm labor. Although Chlamydia trachomatis (Ct) can infect the placenta and decidua, little is known about its effects on trophoblast cell immune function. We have demonstrated that Ct infects trophoblast cells to form inclusions and completes the life cycle within these cells by generating infectious elementary bodies. Moreover, infection with Ct leads to differential modulation of the trophoblast cell's production of cytokines and chemokines. Using two human first trimester trophoblast cell lines, Sw.71 and H8, the most striking feature we found was that Ct infection results in a strong induction of IL-1beta secretion and a concomitant reduction in MCP-1 (CCL2) production in both cell lines. In addition, we have found that Ct infection of the trophoblast results in the cleavage and degradation of NF-kappaB p65. These findings suggest that the effect of a Chlamydia infection on trophoblast secretion of chemokines and cytokines involves both activation of innate immune receptors expressed by the trophoblast and virulence factors secreted into the trophoblast by the bacteria. Such altered trophoblast innate immune responses may have a profound impact on the microenvironment of the maternal-fetal interface and this could influence pregnancy outcome.

Type III secretion systems in symbiotic adaptation of pathogenic and non-pathogenic bacteria

The emergence of multi-drug resistance and bacteria with increased virulence is a familiar refrain to the contemporary microbiologist. Although intense research over the past decade has ascribed much molecular detail to these processes, more esoteric questions remain: for example, why are some bacteria evolving increased virulence towards humans, what are the genes underpinning this virulence potential and what are the selective pressures that favor these traits? A holistic approach that considers the organismal biology of bacteria with their diverse hosts seems appropriate to begin to tackle such issues. As it happens, the type III secretion system is turning out to be a central player in the adaptation of both parasites and mutualists to diverse hosts. With this in mind, human interventions in agriculture, animal husbandry and even drug discovery that could influence the selection of bacteria with improved type III secretion system function should be critically appraised.

[Utility of molecular biology techniques in the diagnosis of sexually transmitted diseases and genital infections]

Historically, the diagnosis of sexually transmitted diseases (STDs) has been difficult. The introduction of molecular biology techniques in microbiological diagnosis and their application to non-invasive samples has produced significant advances in the diagnosis of these diseases. Overall, detection of Neisseria gonorrhoeae by molecular biology techniques provides a presumptive diagnosis and requires confirmation by culture in areas with a low prevalence. For Chlamydia trachomatis infections, these techniques are considered to be the most sensitive and specific procedures for mass screening studies, as well as for the diagnosis of symptomatic patients. Diagnosis of Mycoplasma genitalium infection by culture is very slow and consequently molecular techniques are the only procedures that can provide relevant diagnostic information. For Treponema pallidum, molecular techniques can provide direct benefits in the diagnosis of infection. Molecular techniques are not established for the routine diagnosis of donovanosis, but can be recommended when performed by experts. Molecular methods are advisable in Haemophilus ducreyi, because of the difficulties of culture and its low sensitivity. In genital herpes, molecular techniques have begun to be recommended for routine diagnosis and could soon become the technique of choice. For other genital infections, bacterial vaginosis, vulvovaginal candidosis and trichomoniasis, diagnosis by molecular methods is poorly established. With genital warts, techniques available for screening and genotyping of endocervical samples could be used for certain populations, but are not validated for this purpose.

Emergency care of urban women with sexually transmitted infections: time to address deficiencies

BACKGROUND

Patient education upon diagnosis of a sexually transmitted infection (STI) may effect changes in high-risk sexual behavior.

OBJECTIVE

Describe emergency department (ED) communication with urban female patients treated for STIs.

METHODS

: This secondary analysis of data collected during a study of ED communication used mixed quantitative and qualitative methods. The medical records of female patients ages 18 to 35 presenting to an urban ED for low abdominal/pelvic pain, gynecological complaints, and urinary symptoms (n = 134) were reviewed for STI testing and treatment proportions. A subsample of 30 audiotaped interactions with women treated for STIs were coded for provider assessment of sexual risks and delivery of STI prevention messages.

RESULTS

Audiotape analysis found sexual histories were very limited and only 17% of women received prevention messages. Provider STI treatment had an estimated overall sensitivity of 46% (95% CI, 24.4%-69.0%) and specificity of 66% (95% CI, 61.8%-70.7%).

CONCLUSIONS

Urban female patients treated for an STI in the ED rarely received recommended STI prevention messages. The study raises policy issues regarding the need for quality indicators in acute STI care. Access to STI treatment in other practice settings or by alternative methods need to be strongly considered.

Pattern recognition at the maternal-fetal interface

Intrauterine infections represent a significant threat to fetal well-being and pregnancy outcome. Recent studies suggest that non-immune cells of the maternal-fetal interface can actively recognize and respond to microbes through pattern recognition receptors, in order to control pathogens that may compromise the pregnancy. However, these same innate immune responses may inadvertently lead to excessive inflammation or apoptosis at the maternal-fetal interface. Thus, pattern recognition receptors may play a key role in infection-related pregnancy complications. This review discusses what is currently known about the role of Toll-like receptors and NOD-like receptors in controlling infections at the maternal-fetal interface, and what impact their function may have on pregnancy.

High prevalence of antibodies against Chlamydiaceae and Chlamydophila abortus in wild ungulates using two "in house" blocking-ELISA tests

Few data are available on the prevalence and relevance of chlamydiae in wild mammals, and even fewer studies have been conducted to determine the prevalence of Chlamydophila abortus in wildlife hosts, most probably due to the absence of suitable species-specific serological assays for testing sera from wild animals. In light of this, we have developed two in-house blocking-ELISA tests for detection of antibodies against Chlamydiaceae and C. abortus in wild ungulates, and analyzed the relationship between geographical and biological factors and the prevalence of antibodies against Chlamydiaceae and C. abortus in 434 wild ungulates from Spain, including sera from European wild boar, Red deer, Fallow deer, Roe deer, Mouflon, Barbary sheep, Southern chamois, and Iberian ibex. Serology revealed that 41.7+/-4% of the sera were positive for the b-ELISA-LPS (Chlamydiaceae-specific) and 18.9+/-3% for the b-ELISA-rPOMP (C. abortus-specific). Antibodies against Chlamydiaceae lipopolysaccharide (LPS) were detected in sera from all eight ungulate species, the prevalence ranging from 23 to 60%. Iberian ibex was the only wild ungulate not showing seropositivity to the C. abortus specific polymorphic outer membrane protein (POMP). The prevalence of anti-POMP antibodies in the other seven wild ungulate species ranged from 7 to 40%. While significant seroprevalence differences were detected among species and among sampling regions, no effect of age and sex was observed. The high prevalence levels found should be considered with regards to livestock and human health, and warrant further research.

Chlamydophila abortus infection in the mouse: a useful model of the ovine disease

Chlamydophila (C.) abortus is an obligate intracellular bacterium able to colonize the placenta of several species of mammals, which may induce abortion in the last third of pregnancy. The infection affects mainly small ruminants resulting in major economic losses in farming industries worldwide. Furthermore, its zoonotic risk has been reported in pregnant farmers or abattoir workers. Mouse models have been widely used to study both the pathology of the disease and the role of immune cells in controlling infection. Moreover, this animal experimental model has been considered a useful tool to evaluate new vaccine candidates and adjuvants that could prevent abortion and reduce fetal death. Future studies using these models will provide and reveal information about the precise mechanisms in the immune response against C. abortus and will increase the knowledge about poorly understood issues such as chlamydial persistence.