Toxic shock associated with Clostridium sordellii and Clostridium perfringens after medical and spontaneous abortion

Clinical issues in post-abortion care

This article provides an overview of the clinical issues in post-abortion care, including types of abortion procedures, expected post-abortion course, possible complications, and the components of the post-abortion visit. By providing follow-up care to their patients, NPs can increase continuity of care and promote successful contraceptive use.

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.

Inositol hexakisphosphate-dependent processing of Clostridium sordellii lethal toxin and Clostridium novyi alpha-toxin

Clostridium sordellii lethal toxin and Clostridium novyi α-toxin, which are virulence factors involved in the toxic shock and gas gangrene syndromes, are members of the family of clostridial glucosylating toxins. The toxins inactivate Rho/Ras proteins by glucosylation or attachment of GlcNAc (α-toxin). Here, we studied the activation of the autoproteolytic processing of the toxins by inositol hexakisphosphate (InsP(6)) and compared it with the processing of Clostridium difficile toxin B. In the presence of low concentrations of InsP(6) (<1 μM), toxin fragments consisting of the N-terminal glucosyltransferase (or GlcNAc-transferase) domains and the cysteine protease domains (CPDs) of C. sordellii lethal toxin, C. novyi α-toxin, and C. difficile toxin B were autocatalytically processed. The cleavage sites of lethal toxin (Leu-543) and α-toxin (Leu-548) and the catalytic cysteine residues (Cys-698 of lethal toxin and Cys-707 of α-toxin) were identified. Affinity of the CPDs for binding InsP(6) was determined by isothermal titration calorimetry. In contrast to full-length toxin B and α-toxin, autocatalytic cleavage and InsP(6) binding of full-length lethal toxin depended on low pH (pH 5) conditions. The data indicate that C. sordellii lethal toxin and C. novyi α-toxin are InsP(6)-dependently processed. However, full-length lethal toxin, but not its short toxin fragments consisting of the glucosyltransferase domain and the CPD, requires a pH-sensitive conformational change to allow binding of InsP(6) and subsequent processing of the toxin.

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.

Spontaneous uterine perforation due to clostridial gas gangrene associated with endometrial carcinoma

Few cases of clostridial gas gangrene associated with uterine malignancy have been reported. We report on a 46-year-old woman with clostridial sepsis. On the day of admission due to severe abdominal pain, peritonitis was diagnosed, and computed tomography showed free air in the abdomen. At emergency laparotomy, perforation of the necrotic uterine wall was observed. During hysterectomy, septic shock developed, and life-saving therapy was performed in the intensive care unit after surgery. Pathological examination of the necrotic uterine wall showed grade III endometrial adenocarcinoma of the uterine endometrium (International Federation of Gynecology and Obstetrics stage IIIa) with gas gangrene due to Clostridium perfringens. This report aims to alert gynecologists to the possibility that clostridial gas gangrene of the uterus can occur in patients with peritonitis and intra-abdominal free air. Early recognition and aggressive therapy can save patients' lives.

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.

Lethal toxin is a critical determinant of rapid mortality in rodent models of Clostridium sordellii endometritis

The toxigenic anaerobe Clostridium sordellii is an uncommon but highly lethal cause of human infection and toxic shock syndrome, yet few studies have addressed its pathogenetic mechanisms. To better characterize the microbial determinants of rapid death from infection both in vitro and in vivo studies were performed to compare a clinical strain of C. sordellii (DA-108), isolated from a patient who survived a disseminated infection unaccompanied by toxic shock syndrome, to a virulent reference strain (ATCC9714). Rodent models of endometrial and peritoneal infection with C. sordellii ATCC9714 were rapidly lethal, while infections with DA-108 were not. Extensive genetic and functional comparisons of virulence factor and toxin expression between these two bacterial strains yielded many similarities, with the noted exception that strain DA-108 lacked the tcsL gene, which encodes the large clostridial glucosyltransferase enzyme lethal toxin (TcsL). The targeted removal by immunoprecipitation of TcsL protected animals from death following injection of crude culture supernatants from strain ATCC9714. Injections of a monoclonal anti-TcsL IgG protected animals from death during C. sordellii ATCC9714 infection, suggesting that such an approach might improve the treatment of patients with C. sordellii-induced toxic shock syndrome.

Septic shock due to Klebsiella pneumoniae after medical abortion with misoprostol-only regimen

OBJECTIVE

To report a case of a healthy woman who was admitted to the hospital with septic shock caused by a common uropathogen after self-administration of misoprostol for pregnancy termination.

DESIGN

Case report.

SETTING

Tertiary hospital.

PATIENT(S)

A 38-year-old woman, gravida 5, para 3, who developed septic shock after medical termination of pregnancy.

INTERVENTION(S)

Suction curettage, antibiotic treatment, plasma and platelet transfusions.

MAIN OUTCOME MEASURE(S)

Klebsiella pneumoniae was isolated from blood samples.

RESULT

Ten days after her admission she was discharged home in good condition on oral antibiotics.

CONCLUSION(S)

Severe infections leading to septic shock from common pathogen bacteria can occur after medical termination of pregnancy, independently of the regimen used.

Infections in Pregnancy

Despite advances in peripartum care, maternal morbidity and mortality associated with infections in pregnancy are increasing even in developed countries. Recently published data from the Center for Disease Control's Pregnancy Mortality Surveillance System indicates that although maternal mortality from hemorrhage, embolism, and anesthesia has declined in the United States, the proportion of maternal deaths due to infections has increased. During 1991–7 infection accounted for 13.2% of pregnancy-related deaths overall and 36.3% of abortion-related deaths. The greatest infection risk is found in blacks, older women, women without prenatal care, and women with multiple pregnancy. In the United States pregnancy rates are stable or increasing in these groups. Infection is also a major cause of morbidity and mortality for the fetus and newborn. Many perinatal infections are associated with intra-uterine growth retardation and low birthweight, or cause fetal and neonatal brain injury. Infections, particularly bacterial vaginosis and chorioamnionitis, can result in preterm delivery of live-born infants (delivery before 37 weeks gestation), or stillbirth. A multitude of immunologic, endocrinologic, metabolic, physiologic, and anatomic changes influence the likelihood and course of many infections during pregnancy. Some of these changes are intrinsic, and occur in all normal pregnancies, while others occur to varying degrees in normal and abnormal pregnancies.

Requirements for germination of Clostridium sordellii spores in vitro

Clostridium sordellii is a spore-forming, obligately anaerobic, Gram-positive bacterium that can cause toxic shock syndrome after gynecological procedures. Although the incidence of C. sordellii infection is low, it is fatal in most cases. Since spore germination is believed to be the first step in the establishment of Bacilli and Clostridia infections, we analyzed the requirements for C. sordellii spore germination in vitro. Our data showed that C. sordellii spores require three structurally different amino acids and bicarbonate for maximum germination. Unlike the case for Bacilli species, d-alanine had no effect on C. sordellii spore germination. C. sordellii spores germinated only in a narrow pH range between 5.7 and 6.5. In contrast, C. sordellii spore germination was significantly less sensitive to temperature changes than that of the Bacilli. The analysis of the kinetics of C. sordellii spore germination showed strong allosteric behavior in the binding of l-phenylalanine and l-alanine but not in that of bicarbonate or l-arginine. By comparing germinant apparent binding affinities to their known in vivo concentrations, we postulated a mechanism for differential C. sordellii spore activation in the female reproductive tract.

Undiagnosed cases of fatal Clostridium-associated toxic shock in Californian women of childbearing age

OBJECTIVE

In 2005, 4 Clostridium sordellii-associated toxic shock fatalities were reported in young Californian women after medical abortions. The true incidence of this rare disease is unknown, and a population-based study has never been performed. Additional clostridia-associated deaths were sought to describe associated clinical characteristics.

STUDY DESIGN

Population-based death certificate review and a clinical case definition for clostridial-associated toxic shock identified women with likelihood of dying from a Clostridium infection. Formalin-fixed autopsy tissues underwent immunohistochemical and polymerase chain reaction assays.

RESULTS

Thirty-eight women were suspected of having C sordellii-associated death. Five tested positive for Clostridium species: 3 for Clostridium perfringens, 1 for C sordellii, and 1 for both. Deaths occurred after the medical procedures for cervical dysplasia (n = 2), surgical abortion (n = 1), stillborn delivery (n = 1), and term live birth (n = 1). None had a medical abortion.

CONCLUSION

C sordellii and C perfringens are associated with undiagnosed catastrophic infectious gynecologic illnesses among women of childbearing age.

Two distinct oral routes of misoprostol in mifepristone medical abortion: a randomized controlled trial

OBJECTIVE

To study the efficacy, safety, and acceptability of oral immediately swallowed and buccal misoprostol 800 mcg after mifepristone 200 mg for terminating pregnancy through 63 days since the last menstrual period (LMP).

METHODS

This seven-site study randomly assigned 966 women seeking abortions to oral or buccal misoprostol 800 mcg 24-36 hours after mifepristone 200 mg with 7-14-day follow-up.

RESULTS

Success rates in the oral and buccal groups were 91.3% (389 of 426) and 96.2% (405 of 421), respectively (P=.003; relative risk [RR] 0.95, 95% confidence interval [CI] 0.92-0.98). Ongoing pregnancy occurred in 3.5% (15 of 426) of women who took oral misoprostol compared with 1.0% (4 of 421) of women in the buccal group (P=.012; RR 3.71, 95% CI 1.24-11.07). Through 49 days since the LMP, oral and buccal regimens performed similarly, but success with oral misoprostol decreased as pregnancy advanced. In pregnancies of 57-63 days since the LMP, success with oral misoprostol fell below 90%, whereas that with buccal remained high (oral 85.1% [97 of 114], buccal 94.8% [109 of 115], P=.015, RR 0.90, 95% CI 0.82-0.98). Furthermore, in this gestational age group, there were significantly more ongoing pregnancies among women who took misoprostol orally (7.9% [9 of 114]) compared with buccally (1.7% [2 of 115]; P=.029, RR 4.54, 95% CI 1.0-20.55). Adverse effect profiles were similar, although fever and chills were reported approximately 10% more often among women who took buccal misoprostol. Satisfaction and acceptability were high for both methods.

CONCLUSION

Buccal misoprostol 800 mcg after mifepristone 200 mg is a good option for medical abortion through 63 days since the LMP. Oral misoprostol 800 mcg is also a safe and effective alternative, although success rates diminish with increasing gestational age.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, www.clinicaltrials.gov, NCT00386867

LEVEL OF EVIDENCE

I.

Misoprostol impairs female reproductive tract innate immunity against Clostridium sordellii

Fatal cases of acute shock complicating Clostridium sordellii endometritis following medical abortion with mifepristone (also known as RU-486) used with misoprostol were reported. The pathogenesis of this unexpected complication remains enigmatic. Misoprostol is a pharmacomimetic of PGE(2), an endogenous suppressor of innate immunity. Clinical C. sordellii infections were associated with intravaginal misoprostol administration, suggesting that high misoprostol concentrations within the uterus impair immune responses against C. sordellii. We modeled C. sordellii endometritis in rats to test this hypothesis. The intrauterine but not the intragastric delivery of misoprostol significantly worsened mortality from C. sordellii uterine infection, and impaired bacterial clearance in vivo. Misoprostol also reduced TNF-alpha production within the uterus during infection. The intrauterine injection of misoprostol did not enhance mortality from infection by the vaginal commensal bacterium Lactobacillus crispatus. In vitro, misoprostol suppressed macrophage TNF-alpha and chemokine generation following C. sordellii or peptidoglycan challenge, impaired leukocyte phagocytosis of C. sordellii, and inhibited uterine epithelial cell human beta-defensin expression. These immunosuppressive effects of misoprostol, which were not shared by mifepristone, correlated with the activation of the G(s) protein-coupled E prostanoid (EP) receptors EP2 and EP4 (macrophages) or EP4 alone (uterine epithelial cells). Our data provide a novel explanation for postabortion sepsis leading to death and also suggest that PGE(2), in which production is exaggerated within the reproductive tract during pregnancy, might be an important causal determinant in the pathogenesis of more common infections of the gravid uterus.

The role of glucocorticoids and progestins in inflammatory, autoimmune, and infectious disease

A bidirectional communication exists between the CNS and the immune system. The autonomic nervous system, through neurotransmitters and neuropeptides, works in parallel with the hypothalamic-pituitary-adrenal axis through the actions of glucocorticoids to modulate inflammatory events. The immune system, through the action of cytokines and other factors, in turn, activates the CNS to orchestrate negative-feedback mechanisms that keep the immune response in check. Disruption of these interactions has been associated with a number of syndromes including inflammatory, autoimmune, and cardiovascular diseases, metabolic and psychiatric disorders, and the development of shock. The hypothalamic-pituitary-gonadal axis also plays an important part in regulating immunity through the secretion of sex hormones. Although numerous studies have established a role for immunomodulation by estrogen and testosterone, the role of progesterone is less well understood. Progesterone is crucial for reproductive organ development and maintenance of pregnancy, and more recent studies have clearly shown its role as an important immune regulator. The main focus of this review will be about the role of steroid hormones, specifically glucocorticoids and progesterone, in inflammatory responses and infectious diseases and how dysregulation of their actions may contribute to development of autoimmune and inflammatory disease.