Fatal toxic shock syndrome associated with Clostridium sordellii after medical abortion

The catalytic domains of Clostridium sordellii lethal toxin and related large clostridial glucosylating toxins specifically recognize the negatively charged phospholipids phosphatidylserine and phosphatidic acid

Clostridium sordellii lethal toxin (TcsL) is a potent virulence factor belonging to the large clostridial glucosylating toxin family. TcsL enters target cells via receptor-mediated endocytosis and delivers the N-terminal catalytic domain (TcsL-cat) into the cytosol upon an autoproteolytic process. TcsL-cat inactivates small GTPases including Rac and Ras by glucosylation with uridine-diphosphate (UDP)-glucose as cofactor leading to drastic changes in cytoskeleton and cell viability. TcsL-cat was found to preferentially bind to phosphatidylserine (PS)-containing membranes and to increase the glucosylation of Rac anchored to lipid membrane. We here report binding affinity measurements of TcsL-cat for brain PS-containing membranes by surface plasmon resonance and enzyme-linked immunosorbent assay (ELISA). In addition, TcsL-cat bound to phosphatidic acid (PA) and, to a lesser extent, to other anionic lipids, but not to neutral lipids, sphingolipids or sterol. We further show that the lipid unsaturation status influenced TcsL-cat binding to phospholipids, PS with unsaturated acyl chains and PA with saturated acyl chains being the preferred bindingsubstrates. Phospholipid binding site is localized at the N-terminal four helical bundle structure (1-93 domain). However, TcsL-1-93 bound to a broad range of substrates, whereas TcsL-cat, which is the active domain physiologically delivered into the cytosol, selectively bound to PS and PA. Similar findings were observed with the other large clostridial glucosylating toxins from C. difficile, C. novyi and C. perfringens.

Foot infection by Clostridium sordellii: case report and review of 15 cases in France

We report a case of foot infection by Clostridium sordellii and review 15 human infections registered at a Reference Center in France during the period 1998 to 2011. All strains were found nontoxigenic, lacking the lethal toxin gene coding for TcsL. Like Clostridium septicum, several C. sordellii infections were associated with intestinal neoplasms.

High Proportion of False-Positive Clostridium difficile Enzyme Immunoassays for Toxin A and B in Pediatric Patients

Objectives.

To determine the frequency of false-positive Clostridium difficile toxin enzyme immunoassay (EIA) results in hospitalized children and to examine potential reasons for this false positivity.

Design.

Nested case-control.

Setting.

Two tertiary care pediatric hospitals.

Methods.

As part of a natural history study, prospectively collected EIA-positive stools were cultured for toxigenic C. difficile, and characteristics of children with false-positive and true-positive EIA results were compared. EIA-positive/culture-negative samples were recultured after dilution and enrichment steps, were evaluated for presence of the tcdB gene by polymerase chain reaction (PCR), and were further cultured for Clostridium sordellii, a cause of false-positive EIA toxin assays.

Results.

Of 112 EIA-positive stools cultured, 72 grew toxigenic C. difficile and 40 did not, indicating a positive predictive value of 64% in this population. The estimated prevalence of C. difficile infection (CDI) in the study sites among children tested for this pathogen was 5%–7%. Children with false-positive EIA results were significantly younger than those with true-positive tests but did not differ in other characteristics. No false-positive specimens yielded C. difficile when cultured after enrichment or serial dilution, 1 specimen was positive for tcdB by PCR, and none grew C. sordellii.

Conclusions.

Approximately one-third of EIA tests used to evaluate pediatric inpatients for CDI were falsely positive. This finding was likely due to the low prevalence of CDI in pediatric hospitals, which diminishes the test's positive predictive value. These data raise concerns about the use of EIA assays to diagnosis CDI in children.

Infect Control Hosp Epidemiol 2012;33(2):175-179

Antibiotic resistance, virulence factors and genetics of Clostridium sordellii

Clostridium sordellii is gram positive bacterial pathogen of humans and animals. While the incidence of human-related C. sordellii infection is low, the mortality rate associated with infection is high. Of particular concern are C. sordellii infections after child-birth or medical abortion, which have an almost 100% mortality rate. Recent genetic and epidemiological work has increased our understanding of how this pathogen has evolved and how it causes disease. This review will summarise studies involving the genetics of C. sordellii, including an antibiotic resistance profile, the genetic determinants of virulence and mutagenesis of C. sordellii.

What happens when we routinely give doxycycline to medical abortion patients?

OBJECTIVES

Routine provision of antibiotics following medical abortion is common yet practitioners and professional societies differ on its utility. Our study compares the side effects experienced by women who were prescribed doxycycline following medical abortion to those who were not and assesses the adherence to one prescribed regimen.

STUDY DESIGN

This was a prospective, observational, open-label study from a convenience sample. Women seeking medical abortion were enrolled in nine study sites, including four clinics that routinely prescribe a seven-day course of doxycycline (Doxycycline arm) and five clinics that do not routinely prescribe any antibiotics (No Doxycycline arm). Seven to fourteen days following the administration of mifepristone, women were asked to self-administer a computer-based survey. The survey asked about side effects experienced (both arms) and adherence to the regimen (Doxycycline arm only).

RESULTS

Five hundred eighty-one women were enrolled (278 in the Doxycycline arm and 303 in the No Doxycycline arm). There was a trend toward increased nausea in the Doxycycline arm (47.8% vs. 40.9%; p=.056) and a statistically significant difference in vomiting (25.2% vs. 18.5%; p=.032). Almost all women in the Doxycycline arm reported taking at least one pill, however only 28.3% reported "perfect adherence." The most common reasons reported for taking fewer pills than instructed were that participants were still taking them (beyond 7 days) or that they forgot to take them.

CONCLUSION

Women who were prescribed doxycycline following medical abortion reported moderate adherence and experienced significantly more vomiting than their counterparts.

IMPLICATIONS

In the absence of robust evidence that prescribing 7 days of doxycycline following medical abortion is effective at reducing serious infections, these data can assist the public health community with deciding whether routine provision is the most appropriate strategy.

Haemorrhagic toxin and lethal toxin from Clostridium sordellii strain vpi9048: molecular characterization and comparative analysis of substrate specificity of the large clostridial glucosylating toxins

Large clostridial glucosylating toxins (LCGTs) are produced by toxigenic strains of Clostridium difficile, Clostridium perfringens, Clostridium novyi and Clostridium sordellii. While most C. sordellii strains solely produce lethal toxin (TcsL), C. sordellii strain VPI9048 co-produces both hemorrhagic toxin (TcsH) and TcsL. Here, the sequences of TcsH-9048 and TcsL-9048 are provided, showing that both toxins retain conserved LCGT features and that TcsL and TcsH are highly related to Toxin A (TcdA) and Toxin B (TcdB) from C. difficile strain VPI10463. The substrate profile of the toxins was investigated with recombinant LCGT transferase domains (rN) and a wide panel of small GTPases. rN-TcsH-9048 and rN-TcdA-10463 glucosylated preferably Rho-GTPases but also Ras-GTPases to some extent. In this respect, rN-TcsH-9048 and rN-TcdA-10463 differ from the respective full-length TcsH-9048 and TcdA-10463, which exclusively glucosylate Rho-GTPases. rN-TcsL-9048 and full length TcsL-9048 glucosylate both Rho- and Ras-GTPases, whereas rN-TcdB-10463 and full length TcdB-10463 exclusively glucosylate Rho-GTPases. Vero cells treated with full length TcsH-9048 or TcdA-10463 also showed glucosylation of Ras, albeit to a lower extent than of Rho-GTPases. Thus, in vitro analysis of substrate spectra using recombinant transferase domains corresponding to the auto-proteolytically cleaved domains, predicts more precisely the in vivo substrates than the full length toxins. Except for TcdB-1470, all LCGTs evoked increased expression of the small GTPase RhoB, which exhibited cytoprotective activity in cells treated with TcsL isoforms, but pro-apoptotic activity in cells treated with TcdA, TcdB, and TcsH. All LCGTs induced a rapid dephosphorylation of pY118-paxillin and of pS144/141-PAK1/2 prior to actin filament depolymerization indicating that disassembly of focal adhesions is an early event leading to the disorganization of the actin cytoskeleton.

A case of toxic shock due to clandestine abortion by misoprostol self-administration

Maternal mortality and morbidity are the leading causes of death and illness, respectively, among women of reproductive age in many countries throughout the world. Of all maternal deaths, those related to unsafe abortions are the most widely underestimated, but they are also the most largely preventable. Medical abortion is a safe and reliable method for termination of a pregnancy in early gestation, although it is important to be aware of signs and symptoms of severe infection and toxic shock syndrome after the medical termination of pregnancy; case studies in literature are rarely fatal events. We report the first case of septic shock syndrome following a clandestine pregnancy termination with a misoprostol-only regimen (12 tablets 200 μg each). Autopsy findings and histopathological examination proved that the woman died from septic shock. This case suggests to improve the forensic investigations in case of unsafe, often clandestine, abortion is suspected.

Group A Streptococcus endometritis following medical abortion

Medical abortion is not recognized as a high-risk factor for invasive pelvic infection. Here, we report two cases of group A Streptococcus (GAS; Streptococcus pyogenes) endometritis following medical abortions with a protocol of oral mifepristone and misoprostol.

[Pharmacology of misoprostol (pharmacokinetic data, adverse effects and teratogenic effects)]

Misoprostol is a synthetic analogue of prostaglandin E1. It is used in gynaecology because of its properties of myometrium smooth muscle cells contraction and its effects on the cervix. Misoprostol oral bioavailability is low and several authors have assessed whether the administration by other routes increased its pharmacodynamic effects. This paper summarizes the pharmacokinetic studies after other routes of administration: vaginal, sublingual, buccal or rectal. It also provides an update on its adverse effects and teratogenic effects.

Reduction in infection-related mortality since modifications in the regimen of medical abortion

BACKGROUND

From 2001 to March 2006 Planned Parenthood health centers throughout the United States provided medical abortion by a regimen of oral mifepristone followed 24-48 h later by vaginal misoprostol. In response to concerns about serious infections, in early 2006 Planned Parenthood changed the route of misoprostol administration to buccal and required either routine antibiotic coverage or universal screening and treatment for chlamydia; in July 2007, Planned Parenthood began requiring routine antibiotic coverage for all medical abortions.

METHODS

We performed a retrospective analysis of Planned Parenthood cases assessing the rates of mortality caused by infection following medical abortion during a time period when misoprostol was administered vaginally (2001 through March 2006), as compared with the rate from April 2006 to the end of 2012 after a change to buccal administration of misoprostol and after initiation of new infection-reduction strategies.

RESULTS

The mortality rate dropped significantly in the 81-month period after the joint change to (1) buccal misoprostol replacing vaginal misoprostol and (2) either sexually transmitted infection (STI) screening or routine preventative antibiotic coverage (15 month period) or universal routine preventative antibiotic coverage as part of the medical abortion (66-month period), from 1.37/100,000 to 0.00/100,000, P=.013 (difference=1.37/100,000, 95% CI 0.47-4.03 per 100,000).

CONCLUSION

The infection-caused mortality rate following medical abortion declined by 100% following a change from vaginal to buccal administration of misoprostol combined with screen-and-treat or, far more commonly, routine antibiotic coverage.

SIGNIFICANCE

Deaths from infection following medical abortion declined to zero after a change in the regimen.

Clostridium novyi, sordellii, and tetani: mechanisms of disease

Clostridia represent a diverse group of spore-forming gram positive anaerobes that include several pathogenic species. In general, diseases caused by clostridia are a result of intoxication of the infected host. Thus, clostridial toxins have been targeted for diagnostic, therapeutic, and preventive strategies against infection. Studying the mechanisms of action of clostridial toxins has not only shed light on the pathogenesis of infection but has provided important new insights into cell biology and immunology. A primary purpose of this manuscript is to provide a succinct review on the mechanisms of disease caused by intoxication by the pathogens Clostridium tetani, Clostridium novyi, and Clostridium sordellii.

Identification and characterization of Clostridium sordellii toxin gene regulator

Toxigenic Clostridium sordellii causes uncommon but highly lethal infections in humans and animals. Recently, an increased incidence of C. sordellii infections has been reported in women undergoing obstetric interventions. Pathogenic strains of C. sordellii produce numerous virulence factors, including sordellilysin, phospholipase, neuraminidase, and two large clostridial glucosylating toxins, TcsL and TcsH. Recent studies have demonstrated that TcsL toxin is an essential virulence factor for the pathogenicity of C. sordellii. In this study, we identified and characterized TcsR as the toxin gene (tcsL) regulator in C. sordellii. High-throughput sequencing of two C. sordellii strains revealed that tcsR lies within a genomic region that encodes TcsL, TcsH, and TcsE, a putative holin. By using ClosTron technology, we inactivated the tcsR gene in strain ATCC 9714. Toxin production and tcsL transcription were decreased in the tcsR mutant strain. However, the complemented tcsR mutant produced large amounts of toxins, similar to the parental strain. Expression of the Clostridium difficile toxin gene regulator tcdR also restored toxin production to the C. sordellii tcsR mutant, showing that these sigma factors are functionally interchangeable.

Serious infection associated with induced abortion in the United States

Though serious infection after induced abortion is rare, infections account for one third of abortion-related deaths in the United States. Most fatal cases of infection after induced medical abortion have involved clostridial species. These reported cases share important clinical features that may guide clinicians to earlier recognition and institution of therapy. This article reviews our current knowledge regarding serious clostridial infections postabortion including the typical clinical presentation, pathophysiology, modes of diagnosis, and available treatment.

Fulminant leukemoid reaction due to postpartum Clostridium sordellii infection

Clostridium sordellii is gram positive anaerobic spore forming rod and it has been demonstrated to cause gas gangrene, refractory shock, leukemoid reaction, and pleuroperitoneal effusion due to capillary leak. We report here a case of postpartum female who presented with leukemoid reaction, ascites, pleural effusion, and shock without fever 7 days after normal vaginal home delivery.

Pulmonary arterial hypertension: classification and therapy with a focus on prostaglandin analogs

Pulmonary arterial hypertension, part of the larger spectrum of disorders causing pulmonary hypertension, is a complex and progressive disease of multiple etiologies that ultimately leads to vascular remodeling, right-sided heart failure, and death. Advances in treatment over the past 15 to 20 years have dramatically reduced the morbidity and mortality of the disease, but often have significant drawbacks. Of the more recently approved therapies, the prostaglandin analogs have been shown to have the greatest therapeutic benefit but are also the most difficult to administer, many being given as continuous intravenous infusions in the ambulatory setting. After a case presentation highlighting some of the challenges that accompany treatment with these agents, this article reviews the diagnosis and classification of pulmonary hypertension and pulmonary arterial hypertension and gives a brief overview of the various other pharmacologic agents used in its treatment. A more comprehensive review of the biochemistry of prostaglandins and the pharmacology and clinical use of this class of drugs follows. Recommended treatment guidelines are also discussed.

Rapid, simultaneous detection of Clostridium sordellii and Clostridium perfringens in archived tissues by a novel PCR-based microsphere assay: diagnostic implications for pregnancy-associated toxic shock syndrome cases

Clostridium sordellii and Clostridium perfringens are infrequent human pathogens; however, the case-fatality rates for the infections are very high, particularly in obstetric C. sordellii infections (>90%). Deaths from Clostridium sordellii and Clostridium perfringens toxic shock (CTS) are sudden, and diagnosis is often challenging. Formalin-fixed, paraffin-embedded (FFPE) tissues usually are the only specimens available for sudden fatal cases, and immunohistochemistry (IHC) for Clostridia is generally performed but it cannot identify species. A clear need exists for a rapid, species-specific diagnostic assay for FFPE tissues. We developed a duplex PCR-based microsphere assay for simultaneous detection of C. sordellii and C. perfringens and evaluated DNA extracted from 42 Clostridium isolates and FFPE tissues of 28 patients with toxic shock/endometritis (20 CTS, 8 non-CTS, as confirmed by PCR and sequencing). The microsphere assay correctly identified C. sordellii and C. perfringens in all known isolates and in all CTS patients (10 C. sordellii, 8 C. perfringens, 2 both) and showed 100% concordance with PCR and sequencing results. The microsphere assay is a rapid, specific, and cost-effective method for the diagnosis of CTS and offers the advantage of simultaneous testing for C. sordellii and C. perfringens in FFPE tissues using a limited amount of DNA.

Hypotension after medical termination of pregnancy: think outside of the uterus

BACKGROUND

Under usual circumstances, an ectopic pregnancy would not be generally considered in the initial differential diagnosis of shock after voluntary termination of pregnancy.

OBJECTIVE

To present a rare case of a young woman with shock after voluntary termination of pregnancy due to undiagnosed ectopic pregnancy with concealed hemorrhage.

CASE REPORT

A 37-year-old woman presented to the Emergency Department (ED) 3 days after termination of pregnancy with clinical features of shock. The patient had some evidence of infection and was initially managed as a case of septic shock secondary to possible complication of recent termination of pregnancy. Subsequent work-up led to suspicion of internal bleeding, and ruptured ectopic pregnancy was confirmed and managed successfully.

CONCLUSION

Ruptured ectopic pregnancy can present with a wide range of symptoms and under variable circumstances. Recognition of subtle signs of hemorrhage and consideration of the diagnosis of ruptured pregnancy in the ED will lead to early diagnosis and appropriate management.

Gynecologic clostridial toxic shock in women of reproductive age

Clostridial toxic shock, caused by Clostridium sordellii or Clostridium perfringens, is a rare and largely fatal syndrome among reproductive-aged women with genital tract infection, and may occur following various pregnancy outcomes or without pregnancy. Clinicians should be aware of common clinical features of this very rapidly-progressing syndrome including abdominal pain, tachycardia, hypotension, third-space fluid accumulations, hemoconcentration, and marked leukemoid response, often with lack of fever. In this review, we summarize known cases through mid-2011 and information on clinical presentation, diagnosis, treatment, and results of recent investigations regarding pathogenesis, including germination, toxins, and host response that may have important implications for development of preventive or therapeutic interventions.

[Medical abortion from 12 through 14 weeks' gestation: a retrospective study with 126 patients]

OBJECTIVE

To assess the efficacy of medical abortion performed according to a single protocol from 12 through 14 weeks.

STUDY DESIGN

Retrospective observational study of medical abortions from 12 through 14 weeks performed from January 2007 through March 2009. The protocol combined 600 mg de mifepristone orally, followed 48 h later by 400 μg of misoprostol, administered orally, and repeated after 3h, four times a day (during two days), if patient did not begin to abort. Outcome measures were the abortion rate, the rate of complication, the rate of manual uterine revision or vacuum aspiration, the time of expulsion and the misoprostol dose.

RESULTS

The study included 126 medical abortions. The abortion rate was 98% and the secondary manual revision or vacuum aspiration rate was 41%. The mean time to expulsion was 10.4 (±8.8)h, and the mean misoprostol dose 1040 (±420) μg. Higher parity was significantly correlated with shorter time to expulsion (P=0.02).

CONCLUSION

Medical abortion was consistently effective from 12 through 14 weeks but with high rate of secondary manual revision or vacuum aspiration.

Severe Clostridial Pyomyoma following an Abortion Does Not Always Require Surgical Intervention

Background. Clostridial infection following pregnancy may be fatal, and surgery is considered as the treatment of choice. We suggest a conservative management in selected cases when preservation of fertility is of major importance. Case. A 41-year-old primigravida presented with abdominal pain and fever, one day following dilatation and curettage at 20 weeks of gestation. Her abdomen was diffusely tender, with a uterus enlarged to 20 weeks' gestation. Laboratory studies were consistent with sepsis and hemolysis. CT demonstrated a gas-containing mass compressing the uterine cavity, and presence of air in pelvic veins. Blood cultures were positive for Clostridium perfringens. The patient was treated conservatively, with IV antibiotics and fluid resuscitation, and recovered. Conclusion. In selected cases of infected myoma complicated by clostridial sepsis, refraining from surgical intervention is a possible therapeutic approach.

Non-toxigenic Clostridium sordellii: clinical and microbiological features of a case of cholangitis-associated bacteremia

Toxigenic Clostridium sordellii strains are increasingly recognized to cause highly lethal infections in humans that are typified by a toxic shock syndrome (TSS). Two glucosylating toxins, lethal toxin (TcsL) and hemorrhagic toxin (TcsH) are believed to be important in the pathogenesis of TSS. While non-toxigenic strains of C. sordellii demonstrate reduced cytotoxicity in vitro and lower virulence in animal models of infection, there are few data regarding their behavior in humans. Here we report a non-TSS C. sordellii infection in the context of a polymicrobial bacterial cholangitis. The C. sordellii strain associated with this infection did not carry either the TcsL-encoding tcsL gene or the tcsH gene for TcsH. In addition, the strain was neither cytotoxic in vitro nor lethal in a murine sepsis model. These results provide additional correlative evidence that TcsL and TcsH increase the risk of mortality during C. sordellii infections.

Infectious disease immunohistochemistry in placentas from HIV-positive and HIV-negative patients

Studies comparing placental pathology between human immunodeficiency virus (HIV)-positive and HIV-negative patients have shown conflicting results. In addition, few studies have evaluated the infectious etiology of placental inflammation in HIV-positive patients. We examined a cohort of placentas from 73 HIV-positive and 41 HIV-negative patients to gain a better understanding of the spectrum of placental inflammatory lesions. Bacterial and viral immunohistochemistry (IHC) was run on a subset of placentas (12 HIV-positive and 7 HIV-negative) with the greatest amount of inflammation. Although few histologic differences were seen between the HIV-positive and HIV-negative groups, chorioamnionitis was of a higher stage in the HIV-positive placentas. An infectious agent was found by IHC in 3 of 7 HIV-negative patients (2 Neisseria spp. and 1 group B Streptococcus ). One HIV-positive placenta showed gram-positive cocci on fetal membranes; organisms were not detected by IHC. In 2 patients, the etiologic agent was not suspected prior to IHC. This study identified that acute inflammation is less common in placentas from HIV-positive patients, compared with HIV-negative patients. However, when severe inflammation is present, infectious organisms may be identified by IHC, providing a more specific diagnosis and offering a beneficial impact in maternal and fetal management.

Progesterone analogs influence germination of Clostridium sordellii and Clostridium difficile spores in vitro

Clostridium sordellii and Clostridium difficile are closely related anaerobic Gram-positive, spore-forming human pathogens. C. sordellii and C. difficile form spores that are believed to be the infectious form of these bacteria. These spores return to toxin-producing vegetative cells upon binding to small molecule germinants. The endogenous compounds that regulate clostridial spore germination are not fully understood. While C. sordellii spores require three structurally distinct amino acids to germinate, the occurrence of postpregnancy C. sordellii infections suggests that steroidal sex hormones might regulate its capacity to germinate. On the other hand, C. difficile spores require taurocholate (a bile salt) and glycine (an amino acid) to germinate. Bile salts and steroid hormones are biosynthesized from cholesterol, suggesting that the common sterane structure can affect the germination of both C. sordellii and C. difficile spores. Therefore, we tested the effect of sterane compounds on C. sordellii and C. difficile spore germination. Our results show that both steroid hormones and bile salts are able to increase C. sordellii spore germination rates. In contrast, a subset of steroid hormones acted as competitive inhibitors of C. difficile spore germination. Thus, even though C. sordellii and C. difficile are phylogenetically related, the two species' spores respond differently to steroidal compounds.

Rho/Ras-GTPase-dependent and -independent activity of clostridial glucosylating toxins

Clostridial glucosylating toxins are the main virulence factors of clostridia responsible for gangrene and/or colitis. These toxins have been well characterized to inactivate Rho/Ras-GTPases through glucosylation. However, the signalling pathways downstream of Rho/Ras-GTPases leading to the intracellular effects of these toxins are only partially known. Rac-dependent modification of focal adhesion complexes and phosphoinositide metabolism seem to be key processes involved in actin filament depolymerization and disorganization of intercellular junctions. In addition, clostridial glucosylating toxins induce Rho/Ras-independent intracellular effects such as activation of mitogen-activated protein kinase pathways, which are used by some of these toxins to trigger an inflammatory response.

TcsL is an essential virulence factor in Clostridium sordellii ATCC 9714

Clostridium sordellii is an important pathogen of humans and animals, causing a range of diseases, including myonecrosis, sepsis, and shock. Although relatively rare in humans, the incidence of disease is increasing, and it is associated with high mortality rates, approaching 70%. Currently, very little is known about the pathogenesis of C. sordellii infections or disease. Previous work suggested that the lethal large clostridial glucosylating toxin TcsL is the major virulence factor, but a lack of genetic tools has hindered our ability to conclusively assign a role for TcsL or, indeed, any of the other putative virulence factors produced by this organism. In this study, we have developed methods for the introduction of plasmids into C. sordellii using RP4-mediated conjugation from Escherichia coli and have successfully used these techniques to insertionally inactivate the tcsL gene in the reference strain ATCC 9714, using targetron technology. Virulence testing revealed that the production of TcsL is essential for the development of lethal infections by C. sordellii ATCC 9714 and also contributes significantly to edema seen during uterine infection. This study represents the first definitive identification of a virulence factor in C. sordellii and opens the way for in-depth studies of this important human pathogen at the molecular level.

Defining reality: the potential role of pharmacists in assessing the impact of progesterone receptor modulators and misoprostol in reproductive health

Medical abortion is increasingly heralded as an ideal method for decreasing maternal mortality in health-care resource-deprived areas and as an answer to the shrinking pool of physicians willing to perform abortions. The advent of progesterone receptor modulators (PRMs) and the recent approval by the Food and Drug Administration of ella (ulipristal) as an emergency contraceptive put pharmacists in the center of abortion controversy. Pharmacists, worldwide, need to be aware of the controversy surrounding the introduction of PRMs, particularly with regard to the effect on health policy, their mechanism of action, associated adverse events, and common off-label uses. Once understood, genuine opportunity exists for pharmacists to serve a fundamental role in positively shaping public health policy.

The class A scavenger receptor, macrophage receptor with collagenous structure, is the major phagocytic receptor for Clostridium sordellii expressed by human decidual macrophages

Clostridium sordellii is an emerging pathogen associated with highly lethal female reproductive tract infections following childbirth, abortion, or cervical instrumentation. Gaps in our understanding of the pathogenesis of C. sordellii infections present major challenges to the development of better preventive and therapeutic strategies against this problem. We sought to determine the mechanisms whereby uterine decidual macrophages phagocytose this bacterium and tested the hypothesis that human decidual macrophages use class A scavenger receptors to internalize unopsonized C. sordellii. In vitro phagocytosis assays with human decidual macrophages incubated with pharmacological inhibitors of class A scavenger receptors (fucoidan, polyinosinic acid, and dextran sulfate) revealed a role for these receptors in C. sordellii phagocytosis. Soluble macrophage receptor with collagenous structure (MARCO) receptor prevented C. sordellii internalization, suggesting that MARCO is an important class A scavenger receptor in decidual macrophage phagocytosis of this microbe. Peritoneal macrophages from MARCO-deficient mice, but not wild-type or scavenger receptor AI/II-deficient mice, showed impaired C. sordellii phagocytosis. MARCO-null mice were more susceptible to death from C. sordellii uterine infection than wild-type mice and exhibited impaired clearance of this bacterium from the infected uterus. Thus, MARCO is an important phagocytic receptor used by human and mouse macrophages to clear C. sordellii from the infected uterus.

Inositol hexakisphosphate-induced autoprocessing of large bacterial protein toxins

Large bacterial protein toxins autotranslocate functional effector domains to the eukaryotic cell cytosol, resulting in alterations to cellular functions that ultimately benefit the infecting pathogen. Among these toxins, the clostridial glucosylating toxins (CGTs) produced by Gram-positive bacteria and the multifunctional-autoprocessing RTX (MARTX) toxins of Gram-negative bacteria have distinct mechanisms for effector translocation, but a shared mechanism of post-translocation autoprocessing that releases these functional domains from the large holotoxins. These toxins carry an embedded cysteine protease domain (CPD) that is activated for autoprocessing by binding inositol hexakisphosphate (InsP₆), a molecule found exclusively in eukaryotic cells. Thus, InsP₆-induced autoprocessing represents a unique mechanism for toxin effector delivery specifically within the target cell. This review summarizes recent studies of the structural and molecular events for activation of autoprocessing for both CGT and MARTX toxins, demonstrating both similar and potentially distinct aspects of autoprocessing among the toxins that utilize this method of activation and effector delivery.

The glucocorticoid receptor: a revisited target for toxins

The hypothalamic-pituitary-adrenal (HPA) axis activation and glucocorticoid responses are critical for survival from a number of bacterial, viral and toxic insults, demonstrated by the fact that removal of the HPA axis or GR blockade enhances mortality rates. Replacement with synthetic glucocorticoids reverses these effects by providing protection against lethal effects. Glucocorticoid resistance/insensitivity is a common problem in the treatment of many diseases. Much research has focused on the molecular mechanism behind this resistance, but an area that has been neglected is the role of infectious agents and toxins. We have recently shown that the anthrax lethal toxin is able to repress glucocorticoid receptor function. Data suggesting that the glucocorticoid receptor may be a target for a variety of toxins is reviewed here. These studies have important implications for glucocorticoid therapy.

Severe skin and soft tissue infections and associated critical illness

Skin and soft tissue infections (SSTIs) span a broad spectrum of clinical entities from limited cellulitis to rapidly progressive necrotizing fasciitis, which may be associated with septic shock or a toxic shock-like syndrome. These infections may be the primary instigators of critical illness requiring hospitalization and management in the intensive care unit. Alternatively, these infections may arise from metastatic spread of microorganisms from a distant focus. Regardless of the source, SSTIs may lead to critical illness. The complex interplay of environment, host, and pathogen are important to consider when evaluating SSTIs and planning therapy. This second of a two-part review focuses on severe SSTIs due to Clostridium spp, microorganisms associated with water sources, and polymicrobial/mixed infections. The key to a successful outcome is early identification of risk factors for specific pathogens and early initiation of empiric antimicrobial therapy. For some SSTIs, surgical intervention for diagnosis and/or therapy is also required.

Mifepristone: pharmacology and clinical impact in reproductive medicine, endocrinology and oncology

IMPORTANCE OF THE FIELD

Mifepristone is a synthetic selective progesterone-receptor modulator (SPRM) that is widely used around the globe in the field of reproductive medicine. At present mifepristone is approved in a number of countries for early termination of pregnancy (TOP), cervical dilatation before surgical TOP, and management of early embryonic loss or fetal death. A number of new clinical applications are being developed in gynecology, endocrinology and oncology. Mifepristone has also served as an invaluable tool in the study of steroid hormone biology.

AREAS COVERED IN THIS REVIEW

Current indications for mifepristone are reviewed. New applications for mifepristone under clinical investigation are discussed. In addition, the unique molecular and cellular effects of mifepristone are described.

WHAT THE READER WILL GAIN

The reader will understand the mechanisms of action of mifepristone and the underlying steroid hormone biology. The reader will know the approved clinical indications for mifepristone and appreciate the ongoing basic and clinical research into new applications.

TAKE HOME MESSAGE

Mifepristone is the first-discovered and still most widely used antiprogestin. It has several indications in reproductive medicine and is under investigation for a variety of potential applications in other fields of medicine. The molecular and cellular effects of mifepristone illuminate important aspects of steroid hormone biology.