Purification and physicochemical and biological characterization of a staphylococcal pyrogenic exotoxin

Device-Associated Menstrual Toxic Shock Syndrome

In the 1980s, menstrual toxic shock syndrome (mTSS) became a household topic, particularly among mothers and their daughters. The research performed at the time, and for the first time, exposed the American public as well as the biomedical community, in a major way, to understanding disease progression and investigation. Those studies led to the identification of the cause, Staphylococcus aureus and the pyrogenic toxin superantigen TSS toxin 1 (TSST-1), and many of the risk factors, for example, tampon use. Those studies in turn led to TSS warning labels on the outside and inside of tampon boxes and, as important, uniform standards worldwide of tampon absorbency labeling. This review addresses our understanding of the development and conclusions related to mTSS and risk factors. We leave the final message that even though mTSS is not commonly in the news today, cases continue to occur. Additionally, S. aureus strains cycle in human populations in roughly 10-year intervals, possibly dependent on immune status. TSST-1-producing S. aureus bacteria appear to be reemerging, suggesting that physician awareness of this emergence and mTSS history should be heightened.

The Role of Streptococcal and Staphylococcal Exotoxins and Proteases in Human Necrotizing Soft Tissue Infections

Necrotizing soft tissue infections (NSTIs) are critical clinical conditions characterized by extensive necrosis of any layer of the soft tissue and systemic toxicity. Group A streptococci (GAS) and Staphylococcus aureus are two major pathogens associated with monomicrobial NSTIs. In the tissue environment, both Gram-positive bacteria secrete a variety of molecules, including pore-forming exotoxins, superantigens, and proteases with cytolytic and immunomodulatory functions. The present review summarizes the current knowledge about streptococcal and staphylococcal toxins in NSTIs with a special focus on their contribution to disease progression, tissue pathology, and immune evasion strategies.

Menstrual toxic shock syndrome: case report and systematic review of the literature

Menstrual toxic shock syndrome (mTSS) is a life-threatening disease caused by superantigen-producing Staphylococcus aureus. Incidence ranges from 0·03 to 0·50 cases per 100 000 people, with overall mortality around 8%. In this Grand Round, we present the case of a previously healthy 23-year-old menstruating woman who was diagnosed with mTSS after she presented at our hospital with a septic condition for the second time. The diagnosis was confirmed by fulfilment of the clinical criteria outlined by the US Centers for Disease Control and Prevention (CDC; fever, rash, desquamation, hypotension, and multi-system involvement) as well as a nasal swab positive for the S aureus strain and presence of the gene encoding for toxic shock syndrome toxin 1 (TSST-1). In the early 1980s, when mTSS was first described, use of tampons was considered the main risk factor. Today, the complex interplay between pathogenic factors of S aureus, immunological mechanisms of the host, and changes in the vaginal ecosystem during menstruation has broadened current understanding of the disease, and the CDC criteria have appreciable limitations in everyday clinical practice.

Novel Staphylococcus aureus Secreted Protein Alters Keratinocyte Proliferation and Elicits a Proinflammatory Response In Vitro and In Vivo

Staphylococcus aureus is a leading cause of surgical site infections that results in increased hospital stays due to the development of chronic wounds. Little is known about factors involved in S. aureus' ability to prevent wounds from healing. We discovered a novel secreted protein produced by a surgical site isolate of S. aureus that prevents keratinocyte proliferation. The protein has a molecular weight of 15.7 kDa and an isoelectric point of 8.9. The cloned and purified protein has cytotoxic and proinflammatory properties, as shown in vitro and in vivo. Potent biological effects on keratinocytes and rabbit skin suggest that this protein may play an important role in preventing re-epithelialization. Its lack of homology to known exotoxins suggests that this protein is novel, and this observation is likely to open a new field of research in S. aureus exotoxins. Due to its cytotoxic activities, we call this new protein ε-cytotoxin.

Staphylococcal toxic shock syndrome: superantigen-mediated enhancement of endotoxin shock and adaptive immune suppression

Infectious diseases caused by Staphylococcus aureus present a significant clinical and public health problem. S. aureus causes some of the most severe hospital-associated and community-acquired illnesses. Specifically, it is the leading cause of infective endocarditis and osteomyelitis, and the second leading cause of sepsis in the USA. While pathogenesis of S. aureus infections is at the center of current research, many questions remain about the mechanisms underlying staphylococcal toxic shock syndrome (TSS) and associated adaptive immune suppression. Both conditions are mediated by staphylococcal superantigens (SAgs)-secreted staphylococcal toxins that are major S. aureus virulence factors. Toxic shock syndrome toxin-1 (TSST-1) is the SAg responsible for almost all menstrual TSS cases in the USA. TSST-1, staphylococcal enterotoxin B and C are also responsible for most cases of non-menstrual TSS. While SAgs mediate all of the hallmark features of TSS, such as fever, rash, hypotension, and multi-organ dysfunction, they are also capable of enhancing the toxic effects of endogenous endotoxin. This interaction appears to be critical in mediating the severity of TSS and related mortality. In addition, interaction between SAgs and the host immune system has been recognized to result in a unique form of adaptive immune suppression, contributing to poor outcomes of S. aureus infections. Utilizing rabbit models of S. aureus infective endocarditis, pneumonia and sepsis, and molecular genetics techniques, we aim to elucidate the mechanisms of SAg and endotoxin synergism in the pathogenesis of TSS, and examine the cellular and molecular mechanisms underlying SAg-mediated immune dysfunction.

Human leukocyte antigen class II transgenic mouse model unmasks the significant extrahepatic pathology in toxic shock syndrome

Among the exotoxins produced by Staphylococcus aureus and Streptococcus pyogenes, the superantigens (SAgs) are the most potent T-cell activators known to date. SAgs are implicated in several serious diseases including toxic shock syndrome (TSS), Kawasaki disease, and sepsis. However, the immunopathogenesis of TSS and other diseases involving SAgs are still not completely understood. The commonly used conventional laboratory mouse strains do not respond robustly to SAgs in vivo. Therefore, they must be artificially rendered susceptible to TSS by using sensitizing agents such as d-galactosamine (d-galN), which skews the disease exclusively to the liver and, hence, is not representative of the disease in humans. SAg-induced TSS was characterized using transgenic mice expressing HLA class II molecules that are extremely susceptible to TSS without d-galN. HLA-DR3 transgenic mice recapitulated TSS in humans with extensive multiple-organ inflammation affecting the lung, liver, kidneys, heart, and small intestines. Heavy infiltration with T lymphocytes (both CD4(+) and CD8+), neutrophils, and macrophages was noted. In particular, the pathologic changes in the small intestines were extensive and accompanied by significantly altered absorptive functions of the enterocytes. In contrast to massive liver failure alone in the d-galN sensitization model of TSS, findings of the present study suggest that gut dysfunction might be a key pathogenic event that leads to high morbidity and mortality in humans with TSS.

Co-production of staphylococcal enterotoxin A with toxic shock syndrome toxin-1 (TSST-1) enhances TSST-1 mediated mortality in a D-galactosamine sensitized mouse model of lethal shock

It has previously been reported that staphylococcal enterotoxin A (SEA) is frequently co-expressed with toxic shock syndrome toxin-1 (TSST-1) in menstrual Toxic Shock Syndrome (MTSS)-associated Staphylococcus aureus. It was hypothesized that co-production of SEA and TSST-1 might yield a more virulent strain than one that produced TSST-1 but not SEA. To test this hypothesis, a TSST-1+/SEA- derivative of S. aureus RN3984 (TSST-1+/SEA+) was constructed by plasmid integration, and the isogenic pair were introduced into a D-galactosamine sensitized mouse model of lethal shock. At 72 h, 27 out of 30 (90%) mice inoculated with the parental strain died, as compared to 21 out of 30 (70%) mice inoculated with the isogenic derivative (P=0.05, Fisher's exact test; 1-tailed; 95% confidence limits, 0.80-20.80). Our results suggest that co-production of SEA with TSST-1 does enhance the ability of this strain of S. aureus to induce lethal shock in vivo. This enhanced virulence could be due to an additive or synergistic activity of the toxin combination on T cell proliferation and cytokine production in the animal model.

Activation of bovine lymphocyte subpopulations by staphylococcal enterotoxin C

Staphylococcus aureus is a major mastitis-causing pathogen in cattle. The chronic nature of bovine staphylococcal mastitis suggests that some products or components of S. aureus may interfere with the development of protective immunity. One class of molecules that could be involved are superantigens (SAgs). Although a significant number of mastitis isolates produce SAgs, the effect of these molecules on the bovine immune system is unresolved. To determine if immunosuppression caused by SAgs could play a role in pathogenesis, we monitored bovine lymphocytes exposed to staphylococcal enterotoxin C1 (SEC1). Activation of bovine lymphocytes by either SEC1 or concanavalin A (ConA) was influenced by the gammadelta/alphabeta T-cell ratio in the culture. Compared to ConA-induced stimulation, cultures stimulated with SEC1 generated small numbers of CD4+ alphabeta T cells expressing high levels of interleukin-2 receptor alpha chain (IL-2R alpha) and major histocompatibility complex class II (MHCII), suggesting that SAg exposure does not lead to full activation of these cells. This state of partial activation was most pronounced in cultures with a high gammadelta/alphabeta ratio. In contrast, significant numbers of CD8+ alphabeta T cells expressed high levels of IL-2R alpha and MHCII, regardless of the gammadelta/alphabeta ratio and the stimulant used. CD8+ blasts in cultures stimulated with SEC1 also expressed another activation marker, ACT3, previously detected predominantly on thymocytes and CD4+ T cells. Although gammadelta CD2- and CD2+ T cells expressed MHCII and IL-2R alpha following stimulation with SEC1, only a few cells increased to blast size, suggesting that they were only partially activated. The results suggest ways in which SAgs might facilitate immunosuppression that promotes the persistence of bacteria in cattle and contributes to chronic intramammary infection.

Investigation of the role of the disulphide bond in the activity and structure of staphylococcal enterotoxin C1

The goal of this study was to investigate the role of the disulphide bond of staphylococcal enterotoxin C1 (SEC1) in the structure and activity of the toxin. Mutants unable to form a disulphide bond were generated by substituting alanine or serine for cysteine at positions 93 and/or 110. Although we did not directly investigate the residues between the disulphide linkage, tryptic lability showed that significant native structure in the cystine loop is preserved in the absence of covalent bonding between residues 93 and 110. Since no correlation was observed between the behaviour of these mutants with regard to toxin stability, emesis and T cell proliferation we conclude that SEC1-induced emesis and T cell proliferation are dependent on separate regions of the molecule. The disulphide bond itself is not an absolute requirement for either activity. However, conformation within or adjacent to the loop is important for emesis. Although mutants with alanine substitutions were not emetic, those with serine substitutions retained this activity, suggesting that the disulphide linkage stabilizes a crucial conformation but can be replaced by residues which hydrogen bond.

Predictions of T-cell receptor- and major histocompatibility complex-binding sites on staphylococcal enterotoxin C1

We have focused on regions of staphylococcal enterotoxin C1 (SEC1) causing immunomodulation. N-terminal deletion mutants lacking residues 6 through 13 induced T-cell proliferation similar to that induced by native toxin. However, mutants with residues deleted between positions 19 and 33, although nonmitogenic themselves, were able to inhibit both SEC1-induced T-cell proliferation and binding of the native toxin to major histocompatibility complex (MHC) class II. Presumably, these deletions define a part of SEC1 that interacts with the T-cell receptor. Three synthetic peptides containing residues located in a region analogous to the alpha 5 groove of SEC3 had residual mitogenic activity or blocked T-cell proliferation induced by SEC1 and appear to recognize the same site as SEC1 on a receptor for the toxin, presumably MHC class II. We conclude that isolated portions of the SEC1 molecule can retain residual mitogenic activity but that the entire protein is needed to achieve maximal superantigenic stimulation. Our results, together with the results of other investigators, support a model in which SEC1 binds to an alpha helix of MHC class II through a central groove in the toxin and thereby promotes or stabilizes the interaction between antigen-presenting cells and T cells.

Characterization of novel type C staphylococcal enterotoxins: biological and evolutionary implications

The type C staphylococcal enterotoxins (SEC) are a group of highly conserved proteins with significant immunological cross-reactivity. Although three antigenically distinct SEC subtypes (SEC1, SEC2, and SEC3) have been reported in the literature, we observed that the isoelectric points of SEC from several Staphylococcus aureus isolates are different from those of any of these three subtypes. This observation led us to propose that additional SEC molecular variants exist. For assessment of this possibility, the sec genes from representative human, animal, and food isolates were cloned and sequenced. The toxins encoded by the 18 isolates used in this study included five unique SEC proteins in addition to SEC1, SEC2, and SEC3. Six of the SEC proteins (including SEC1, SEC2, and SEC3) were produced by human and food isolates. Analysis of seven bovine and ovine isolates showed that isolates from each animal species produced a unique host-specific SEC. All of the SEC caused lymphocyte proliferation, although some of the toxins differed in their ability to stimulate cells from several animal species. An explanation for these results, which is supported by our phenotypic analysis of Sec+ staphylococcal isolates, is that toxin heterogeneity is due to selection for modified SEC sequences that facilitate the survival of S. aureus isolates in their respective hosts.

Residues 20, 22, and 26 determine the subtype specificities of staphylococcal enterotoxins C1 and C2

Nonconserved residues of staphylococcal enterotoxin C1 (SEC1) were converted to their counterparts in SEC2. The mutants that resulted were examined for reactivity with monoclonal antibodies (MAbs). Substitution at position 20, 22, or 26 interfered with binding of an SEC1-specific MAb. SEC1 mutants with substitutions at all three positions reacted only with an SEC2-specific MAb. Antibody-binding patterns were not associated with isoelectric point differences. All mutants retained biological activity.

Staphylococcal and streptococcal pyrogenic toxins involved in toxic shock syndrome and related illnesses

Toxic-shock syndrome (TSS) is an acute onset, multiorgan illness which resembles severe scarlet fever. The illness is caused by Staphylococcus aureus strains that express TSS toxin-1 (TSST-1), enterotoxin B, or enterotoxin C. TSST-1 is associated with menstrual TSS and approximately one-half of nonmenstrual cases; the other two toxins cause nonmenstrual cases, 47% and 3%, respectively. The three toxins are expressed in culture media under similar environmental conditions. These conditions may explain the association of certain tampons with menstrual TSS. Biochemically, the toxins are all relatively low molecular weight and fairly heat and protease stable. Enterotoxins B and C, share nearly 50% sequence homology with streptococcal scarlet fever toxin A; they share no homology with TSST-1 despite sharing numerous biological properties. Numerous animal models for development of TSS have suggested mechanisms of toxin action, though the exact molecular action is not known. The toxins are all potent pyrogens, induce T lymphocyte proliferation, requiring interleukin 1 release from macrophages, suppress immunoglobulin production, enhance endotoxin shock, and enhance hypersensitivity skin reactions. The genetic control of the toxins has been studied and suggests the exotoxins are variable traits. Some additional properties of TSS S. aureus which facilitate disease causation have been clarified.

Toxic shock syndrome-associated staphylococcal and streptococcal pyrogenic toxins are potent inducers of tumor necrosis factor production

Toxic shock syndrome-associated staphylococcal and streptococcal exotoxins were tested for an ability to induce the production of tumor necrosis factor (TNF). Staphylococcal enterotoxins B and C1, along with streptococcal pyrogenic exotoxin A, all induced TNF production in a dose-dependent manner, with production peaking on the average at 3 days but continuing over the 6 days tested. This time course of exotoxin-induced TNF production contrasts with the 1-day peak-2-day duration observed with endotoxin as the stimulus and may be significant to development of toxic shock syndrome.

Biological and immunological properties of the carboxyl terminus of staphylococcal enterotoxin C1

Comparisons of recently published primary sequences of staphylococcal and streptococcal pyrogenic toxins prompted an evaluation of biological and immunological properties of the C terminus of staphylococcal enterotoxin C1. The 59 N-terminal amino acids were deleted from the toxin by digestion with trypsin. The resulting fragment (Mr, 20,659) contained the remaining 180 C-terminal residues. This fragment (Trp F1) consisted of two polypeptide chains (Trp F1a and Trp F1b) linked by cysteine residues. Trp F1 was mitogenic, pyrogenic, and enhanced susceptibility of rabbits to lethal endotoxin shock. In addition, this fragment contained at least one antigenic epitope that cross-reacted with enterotoxin B.

Cloning and characterization of the gene, speC, for pyrogenic exotoxin type C from Streptococcus pyogenes

The structural gene of streptococcal pyrogenic exotoxin type C (SPE C) was cloned from the chromosome of Streptococcus pyogenes strain T18P into Escherichia coli using pBR328 as the vector plasmid. Subcloning enabled the localization of the gene (speC) to a 1.7 kb fragment. Partially purified E. coli-derived SPE C and purified streptococcal-derived SPE C, were shown to have the same molecular weight (23,800) and biological activities. A DNA probe, prepared from cloned speC, cross-hybridized with the structural genes of SPE A and SPE B indicating relatedness at the nucleotide level. The speC-derived probe also hybridized to a fragment of CS112 bacteriophage DNA containing the phage attachment site.

Cross-neutralization of staphylococcal and streptococcal pyrogenic toxins by monoclonal and polyclonal antibodies

We evaluated cross-reactivity of antibodies against staphylococcal and streptococcal pyrogenic toxins. Monoclonal antibodies against staphylococcal enterotoxin (ET) C1 and streptococcal pyrogenic exotoxin (SPE) A were tested for reactivity with homologous and heterologous pyrogenic toxins in vitro. Ten immunoglobulin G1 anti-ET C1 monoclonal antibodies showed little or no cross-reactivity in an enzyme-linked immunosorbent assay, but many of these could neutralize the mitogenic effect of ET B, SPE A, or both. Two immunoglobulin M anti-ET C1 monoclonal antibodies and eight immunoglobulin M anti-SPE A monoclonal antibodies showed extensive cross-reactivity in the enzyme-linked immunosorbent assay and the mitogenicity neutralization assay. No cross-reactivity was observed with SPE C or toxic shock syndrome toxin 1. Rabbits immunized against ET B, ET C1, or SPE A were resistant to challenge with the immunizing toxin. In addition, reciprocal immunity was stimulated by the two ETs, and immunity to SPE A provided protection against ET B but not ET C1. These results show that staphylococcal and streptococcal pyrogenic toxins which share sequence homology have common antigenic determinants which may not be detected in Ouchterlony immunodiffusion assays.

Nucleotide sequence of the staphylococcal enterotoxin C1 gene and relatedness to other pyrogenic toxins

The nucleotide sequence for the structural gene entC1 encoding staphylococcal enterotoxin C1 was determined. The gene contained 801 bp and coded for a protein of 266 amino acids. Of these, 27 comprised the signal peptide. Cleavage of the signal peptide resulted in a mature protein with 239 amino acids and a calculated molecular weight of 27,496. The nucleotide sequence of entC1 shared considerable homology (74% and 59%, respectively) with genes encoding enterotoxin B and streptococcal pyrogenic exotoxin A. A similar degree of amino acid homology was observed after alignment of the respective proteins. Thus, certain regions of these three toxin molecules possess structural similarities that may be responsible for shared biological properties.

Expression of staphylococcal enterotoxin C1 in Escherichia coli

The structural gene encoding staphylococcal enterotoxin C1 was cloned into Escherichia coli and localized on a 1.5-kilobase HindIII-ClaI DNA fragment by subcloning. The toxin was partially purified from E. coli clones and shown to be immunologically identical to enterotoxin C1 from Staphylococcus aureus. The cloned toxin also had the same molecular weight (26,000) and charge heterogeneity as staphylococcus-derived enterotoxin. Toxins from both sources were equally biologically active.

Enhancement of endotoxin-induced isolated renal tubular cell injury by toxic shock syndrome toxin 1

The pathogenesis of toxic shock syndrome (TSS) remains unknown. On the basis of experimental data, it has been hypothesized that staphylococcal TSS Toxin 1 (TSST-1) may interact synergistically with low levels of endotoxin and give rise to many of the clinical findings. We have demonstrated previously that lipid A, the biologically active component of lipopolysaccharide (LPS), or endotoxin, induces dose-dependent necrosis of isolated rat renal tubular cells (RTCs). In the present studies, the authors investigated whether this injury could be augmented by TSST-1. The viability of RTCs was assessed by vital dye exclusion. Incubation of freshly isolated rat RTCs with either 1 ng/ml of TSST-1 or 0.1 ng/ml LPS or lipid A had minimal cytotoxicity (less than 6%). Exposure of RTCs to 1 ng/ml TSST-1 for 20 minutes, followed by washing, resulted in a significant enhancement of cytotoxicity when RTCs were exposed to 0.1 ng/ml LPS or lipid A. The sensitization of RTCs by TSST-1 to LPS- or lipid-A-induced injury was prevented by methylamine and chloroquine, two inhibitors of receptor-mediated endocytosis (RME). Chelation of extracellular calcium by 2 mM EGTA also blocked the TSST-1-induced sensitization of RTCs to LPS or lipid A. Inhibition of RTC arachidonic acid metabolism by methylprednisolone, indomethacin, ibuprofen, and piriprost significantly inhibited RTC necrosis induced by TSST-1 and LPS or lipid A by 33-62%. Thiourea and deferoxamine, agents which ameliorate oxidant injury, also inhibited this synergistic injury by 34-67%. Thus, TSST-1 enhanced the cytotoxic effects of LPS/lipid A, and the sensitization of RTCs appeared to involve RME or TSST-1. Oxidative metabolism of arachidonic acid and generation of reactive oxygen species appeared to participate in LPS/lipid-A-mediated RTC death.

Animal studies of toxic shock syndrome

Toxic shock syndrome (TSS) was first described in 1978 and since that year over 2990 cases have been reported to the Communicable Disease Center. The estimated case-fatality rate is 5.6%. The disease is characterized by fever, hypotension, rash, desquamation, and involvement of at least three other organ systems. Approximately 85% of the cases are menstrually related and tampon use has been identified as a risk factor. The remaining 15% of the cases occur in both sexes and are not specifically related to age or geographic location. In all cases where sought there is evidence for infection by Staphylococcus aureus. Nearly all S. aureus isolates are phage type 52/29 and elaborate a unique exotoxin (toxic shock toxin). This review explores both the successful and unsuccessful attempts to induce toxic shock or a TSS-like syndrome in animals other than man. The review identifies the baboon as an animal model of TSS and discusses the clinical and pathologic sequellae, in this species, after exposure to purified toxic shock toxin.

Induction of human interleukin-1 by a product of Staphylococcus aureus associated with toxic shock syndrome

Certain strains of Staphylococcus aureus associated with toxic shock syndrome elaborate material that induces human blood monocytes to secrete interleukin-1 (IL-1). IL-1 was detected both by its ability to cause fever in rabbits using the leukocytic pyrogen (LP) assay and by its mitogenic activity towards thymocytes in the so-called lymphocyte-activating factor (LAF) assay. Anti-human IL-1 prevents the manifestation of both activities. Filtrates of control strains of S. aureus manifest neither activity. Thus, culture filtrates derived from toxic shock syndrome (TSS)-associated strains cause biphasic fever in rabbits when injected intravenously. The fever lasts several hours. Plasma taken at the peak of the fever and injected into a second set of rabbits produces a brief monophasic fever typical of LP. Further, human monocytes release LP when incubated with TSS filtrates in vitro. The monocyte products also stimulate the proliferation of mouse thymocytes in the presence of phytohemagglutinin in a manner characteristic of LAF. A bacterial filtrate is much less effective without an intermediate incubation with monocytes. The stimulation of monocyte IL-1 production is easily quantified, provides a simple method of assaying the TSS toxin, and since it involves human cells, is directly relevant to the human disease. The assay was used to monitor the purification of TSS toxin. Only 0.1 ng/ml of the purified material is required to induce monocyte IL-1 production. It is thus more potent than endotoxin. In contrast to endotoxin, its effect is not blocked by polymyxin B. We conclude that in TSS the sudden fever and probably other components of the acute phase response may be attributed to a massive release of IL-1.

Toxic shock syndrome: a review

Toxic shock syndrome (TSS) is an acute illness that affects multiple organ systems. It is a disorder of particular interest to obstetricians and gynecologists because it primarily affects otherwise healthy menstruating women who use tampons. The pathogenesis remains unknown. However, Staphylococcus aureus has been isolated from either focal lesions or the vagina in most cases and a staphylococcal exotoxin is believed to be the causative agent. The epidemiologic characteristics, risk factors, clinical findings, criteria for diagnosis, and recommendations for treatment are reviewed.

Effects of carrier ampholyte contamination on the biological and biochemical properties of streptococcal pyrogenic exotoxin type C

Three streptococcal pyrogenic exotoxins (SPEs), designated as SPE A, B, and C, have been purified and characterized. Routine purification of the SPEs includes the technique of isoelectric focusing. An earlier study showed that the removal of commercial carrier ampholytes (Ampholines) from SPE was difficult. The physiochemical properties of SPE C were previously reported; however, the SPE C preparation used in those experiments was contaminated with Ampholines. As an alternative to Ampholines, we used simple buffers to generate the isoelectric focusing pH gradient and used this SPE C in a comparative study to evaluate the effects of Ampholine contamination on the biological and biochemical properties of this toxin. We found that Ampholine contamination overestimates protein concentration; consequently, the biological activity of SPE C was actually greater than reported. The most serious effect of Ampholines in SPE C was on amino acid analysis. The presence of Ampholines causes an apparent increase in neutral amino acids and a decrease in basic amino acids.

Characterization of Staphylococcus aureus isolates from patients with toxic shock syndrome, using polyethylene infection chambers in rabbits

Isolates of Staphylococcus aureus from patients with toxic shock syndrome (TSS) were compared with non-TSS strains of S. aureus with respect to their virulence in rabbits. When the organisms were injected into subcutaneous chambers (perforated polyethylene golf balls) to assess virulence, a rapid mortality was observed with TSS but not with non-TSS strains. Of 16 TSS strains, 11 caused lethal infections in 33 rabbits tested, and none of the 5 control strains caused mortality in 10 rabbits. This evidence of enhanced virulence associated with TSS strains did not appear to be associated with the size of the inoculum. In addition, strains which produced lethal infections appeared to do so despite a reduction in the size of the original inoculum during the first 24 h. All of the TSS strains and none of the non-TSS strains elaborated extracellular protein(s) with a neutral pI when grown in a dialyzed beef heart medium. No other physiological difference was noted between the TSS and non-TSS strains.

Toxic shock syndrome

Toxic shock syndrome (TSS) is an exotoxin-mediated illness that occurs primarily in young menstruating women who use tampons. The syndrome ranges from a potentially fatal disease characterized by hypotension and failure in multiple organ systems to a less severe condition commonly misdiagnosed as a nonspecific viral illness or gastroenteritis. Physicians should recognize that an exanthematous, febrile illness that recurs during menstruation or that occurs primarily in the postoperative or postpartum period and in association with staphylococcal infections may be TSS even in the absence of requisite diagnostic criteria. Unless TSS can be excluded with reasonable certainty, appropriate cultures should be obtained, with treatment initiated presumptively. In all menstrual cases, women should be advised to avoid tampon use indefinitely.

Scarlet fever, Toxic-shock syndrome and the Staphylococcus

A case of scarlet fever studied in 1959 and caused by Staphylococcus aureus, phage type 52/52a/80 infection of a surgical burn is reported. The literature is reviewed and data are presented which indicate the distinct antigenicity of the erythrogenic toxins of staphylococci and group A streptococci. The patient developed neutralizing antibodies to staphylococcal toxin which disappeared ten months after infection. The similarity of the rashes and desquamation of the skin of several diseases caused by staphylococci indicate at least one common toxin.

Molecular basis of fever in humans

This review presents several areas of research on the pathogenesis of fever in humans and updates new information concerning the role of fever in host defense mechanisms. Fever is mediated by a polypeptide of phagocytic cell origin called leukocytic pyrogen. Several agents and disease processes are associated with the synthesis and release of leukocytic pyrogen. Although the original studies on leukocytic pyrogen suggested that the neutrophil was the primary source, recent experiments indicate the mononuclear phagocyte to be the major producer of leukocytic pyrogen. The mechanism by which human monocytes are stimulated to produce leukocytic pyrogen is discussed, including the effects of corticosteroids, estrogens and antipyretics on the synthesis of leukocytic pyrogen in vitro. The ability of leukocytic pyrogen to alter the hypothalamic thermoregulatory center by increasing arachidonic acid metabolite levels is the most likely mechanism by which leukocytic pyrogen initiates fever. Antipyretics prevent the synthesis of certain cyclooxygenase metabolites, which accounts for their ability to reduce fever. Studies on the chemical and physical properties of human leukocytic pyrogen are reviewed and form the basis for current experiments on the similarities between leukocytic pyrogen and lymphocyte activating factor. These studies suggest that leukocytic pyrogen, in addition to producing fever, also stimulates non-hypothalamic cells involved in aspects of the acute-phase response. In this regard, leukocytic pyrogen may be an important mechanism for host defenses. Hyperthermia may also be beneficial to the host but is distinct from fever; the role of leukocytic pyrogen as well as hyperthermia as a defense mechanism is discussed.

Toxic shock syndrome in Canada

Since 1976, 53 confirmed or suspected cases of toxic shock syndrome (TSS) have been reported in Canada. Twenty-two cases occurred in 1980, and by October 1981 another 21 had been reported. In Canada, like the United States, where nearly 1200 cases have been recorded, TSS appears to be associated with tampon use, although a few cases have occurred in males and in nonmenstruating women. Of the 53 patients 3 died. The enterotoxin produced by Staphylococcus aureus is probably responsible for TSS. Manufacturers of tampons have now placed warning labels on tampon boxes and information on TSS in the instruction inserts. Women should select tampons of appropriate absorbency for the various stages of menstruation.

An epidemic of Kawasaki syndrome in Hawaii

A community-wide outbreaks of Kawasaki syndrome, apparently the first in the United States, occurred in Hawaii in the first half of 1978. Twenty-seven of the 33 cases were subjected to intensive epidemiologic and microbiologic study. Patients with Kawasaki syndrome, compared to the general population, more often had Japanese ancestry, high-income status, and possibly a history of respiratory infection in the preceding month (44%). Staphylococcus aureus was not found in high frequency in the patients (15%), and viral cultures and serologic studies, immune electron microscopy, and guinea pig and primate inoculation did not reveal a causative microorganism. Febrile illnesses in guinea pigs inoculated with a skin biopsy specimen should not be further passaged.

Enhancement of host susceptibility to lethal endotoxin shock by staphylococcal pyrogenic exotoxin type C

Staphylococcal pyrogenic exotoxin (PE) ty pe C enhanced the susceptibility of rabbits to lethal shock by endotoxin by as much as 50,000-fold. A graph of log PE type C dose used for pretreatment versus log 50% lethal dose of endotoxin gave a straight line with a slope of approximately -1. Rabbits that received PE type C alone showed fevers only, but those given both PE ty pe C and endotoxin showed initial fever followed by hypothermia, labored breathing, diarrhea, evidence of vascular collapse, and finally death. When a PE type C dose of 3 micrograms/kg was used, pretreatment of the animals with PE for 2 h before giving the endotoxin was required to obtain maximal susceptibility. However, when 15 micrograms of PE type C per kg was utilized, the endotoxin could be given before, concurrently, or after PE type C. The capacity of PE type C to prepare rabbits for enhanced susceptibility to endotoxin was lost after 24 to 48 h. Animals could be protected from enhanced susceptibility to endotoxin by prior immunization with either PE type C or endotoxin. However, 30% of the rabbits which were immunized with PE type C failed to develop immunity, and after three injections of PE type C, these animals developed gram-negative bacteremia and succumbed. In addition, rabbits with diarrhea initially, possibly caused by Pasteurella infection, died less than 24 h after a single injection of PE type C.

Toxic shock syndrome -- some new features

A thirty-year-old female presented with a high fever, conjunctivitis, confusion, vomiting, watery diarrhoea, diffuse erythroderma, shock and oliguric renal failure. Staphylococcus aureus phage 29/52 (Group 1) was isolated from a high vaginal swab. In addition to all the previously reported features which defined toxic shock syndrome, there were pustular skin vesicles, altered red cell morphology, and severe myocardial involvement. Treatment with fluid replacement, cloxacillin, haemodialysis, positive inotropic agents, and supportive measures resulted in a full recovery.

The clinical spectrum of toxic shock syndrome

Toxic shock syndrome (TSS) is a recently recognized acute multisystem illness that may recur. Epidemiologic links with menstruation and use of tampons have been identified. We report the cases of seven patients (six women and one man), 12 to 31 years old, seen over nine months, who met the criteria for TSS. Four were menstruating at onset. All had hypotension, fever, erythematous rash and distal desquamation. A prodrome of myalgias and diarrhea occurred in all patients. Clinical features of the acute illness included pharyngitis, conjunctivitis, leukocytosis and renal dysfunction (7), hepatobiliary abnormalities (6), mental confusion (6) and coagulopathy (4). In three patients, examination of cerebrospinal fluid showed abnormalities. The illness progressed in three patients to adult respiratory distress syndrome and significant cardiac dysfunction. Staphylococcus aureus was isolated from mucosal sites in six. The disease recurred in two. There were no deaths. Possible transmissibility was illustrated by two patients, a married couple, with simultaneous illnesses. Pathophysiologic features of TSS suggest a toxicogenic cause. Management consists of early recognition, vigorous fluid resuscitation, inotropic support as needed, discontinuation of tampon use and treatment with antistaphylococcal antimicrobic drugs.

Vaginal isolates of Staphylococcus aureus associated with toxic shock syndrome

Staphylococcus aureus has been isolated from vaginal fluids of women with toxic shock syndrome (TSS), a multisystem disease with onset usually during menses. A total of 15 vaginal isolates of S. aureus from TSS patients were compared with 18 vaginal isolates from women without TSS. Phenotypic traits which were significantly more frequent in the TSS group of strains than in the non-TSS group were arsenate resistance, proteolysis of hemoglobin, reduced hemolysis of sheep blood in agar medium, and lack of lethality of culture filtrates for chicken embryos and rabbits. In addition, isoelectric focusing of ethanol extracts of culture filtrates showed differences between the two groups in the occurrence of two proteins. All hemolytic and chicken embryo-lethal strains (3 TSS strains and 14 non-TSS strains) produced an extracellular protein with an isoelectric point of 8.6. In contrast, all TSS strains, but only one-half of non-TSS strains, released a protein with an isoelectric point of 7.0 and an apparent subunit molecular weight of 22,000.

Kawasaki syndrome: description of two outbreaks in the United States

Investigation of two outbreaks of Kawasaki syndrome (KS) in the United States in 1979 and in 1980 revealed no evidence of person-to-person transmission or of a common-source exposure among patients. Questionnaire data showed that KS was more likely to occur in children of middle and upper socioeconomic status than in those of lower status (P less than 0.05 and P less than 0.001 for the respective outbreaks) and that patients with KS had a higher incidence of an antecedent, primarily respiratory illness than did controls matched for age, sex, and race (83% of patients in the first outbreak vs. 30% of one control group, P less than 0.01, and vs. 36% of another control group, P less than 0.02; and 56% of patients in the second outbreak vs. 32% of their controls, P less than 0.02). However, laboratory studies did not identify an etiologic agent for either KS or for the antecedent illness that may be a risk factor for KS.

Toxic shock syndrome

Eight cases of toxic shock syndrome, confirmed by Center for Disease Control criteria, involved women who were menstruating and were tampon users. Each patient had severe febrile illness with rash, associated hypotension, renal and liver function abnormalities, pharyngitis and vaginitis. An examination of the literature indicates that cases that were reported as adult Kawasaki disease may actually have been toxic shock syndrome.

Staphylococcal scarlet fever: role of pyrogenic exotoxins

Staphylococcal pyrogenic exotoxin (PE) types A and B were tested for their role in production of a scarlatiniform rash. The PEs elicited minimal skin reactions after intracutaneous injection into animals not presensitized to the toxins. In contrast, erythematous injection into animals not presensitized to the toxins. In contrast, erythematous and edematous rashes were produced after administration of either PE to animals presensitized to homologous toxin. After 3 to 4 days, the erythematous areas showed membranous desquamation. Staphylococcal PEs also enhanced delayed and Arthus hypersensitivity skin reactions developed against unrelated proteins; the reactions subsequently desquamated. In addition, animals previously sensitized to either staphylococcal PE type developed scarlatiniform rashes after challenged with heterologous staphylococcal or any group A streptococcal PE. The data suggest that staphylococcal PEs produce scarlet fever-like rashes comparable to group A streptococcal PEs and that all PE types contain a common core moiety against which delayed hypersensitivity may be developed.

Purification and characterization of staphylococcal pyrogenic exotoxin type B

Staphylococcal pyrogenic exotoxin (PE) type B was purified and characterized biochemically and biologically. The exotoxin was purified from cell-free culture supernatant fluids by using differential precipitation with ethanol and resolubilization in pyrogen-free distilled water followed by preparative thin-layer isoelectric focusing. A final purification of 153-fold was achieved on the basis of the capacity of the exotoxin to produce fever. The toxin migrated as a homogeneous protein with a molecular weight of approximately 18 000 when tested with sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Hyperimmune antisera raised against the purified exotoxin reacted with partially purified toxin in an immuno-diffusion assay to form a single precipitin line. The isoelectric point of the PE was estimated to be 8.5. Alanine was identified as the N-terminal amino acid. The exotoxin contained significant amounts of lysine but few aromatic amino acids. The PE was pyrogenic and enhanced host susceptibility to lethal shock and myocardial damage by endotoxin. In addition, the exotoxin was a potent nonspecific lymphocyte mitogen and suppressed immunoglobulin M synthesis against sheep erythrocytes.

Toxic-shock syndrome: epidemiologic features, recurrence, risk factors, and prevention

Surveillance for toxic-shock syndrome (TSS) in Wisconsin detected 38 cases with onsets from September 1975 through June 1980. Thirty-seven of the cases occurred after January 1, 1979; 37 of the patients were women, 35 cases occurred during menses; 38 patients were white; and one patient died. Cervical or vaginal cultures were obtained before antibiotic therapy in 23 patients, and 17 cultures were positive for Staphylococcus aureus. Ten patients had at least one recurrent episode during subsequent menstrual periods. The recurrence rate was lower in patients who had been treated with beta-lactamase-resistant antibiotics. Thirty-five patients were matched for age and menstruation to 105 controls: 34 of 35 cases (versus 80 of 105 controls) used tampons during every menstrual period (P < 0.01); nine of 35 cases (versus 64 of 105 controls) practiced contraception (P < 0.001). In Wisconsin the minimum incidence of TSS as defined by clinical criteria is 6.2 cases per 100,000 menstruating women per year. The rate of TSS among menstruating women younger than 30 years was 2.4 to 3.3 times the rate among those who were 30 or older.

Mitogenic activity of cytoplasmic membranes isolated from L-forms of Staphylococcus aureus

Cytoplasmic membranes of L-forms of Staphylococcus aureus exerted a strong mitogenic effect on splenocytes of athymic nude mice as well as normal mice, while a cytoplasmic fraction of the same bacteria did not show definite mitogenicity. The mitogenic principle(s) of the membrane fraction was resistant to treatment with trypsin and was heat stable (at 100 C for 10 min). The active principle(s) in the insoluble residue of the membrane fraction digested with trypsin was not extracted with cold acetone, but could be solubilized by extraction with a cold chloroform-methanol mixture (2:1, v/v). The mitogenic principle(s) in the extract was fractionated by silicic acid column chromatography. Among five fractions separated by chromatography, fractions eluted with chloroform-methanol mixtures (1:1 and 1:20, v/v) were found to be strongly mitogenic. The cytoplasmic membranes of the L-forms also exerted a definite mitogenic effect on guinea pig splenocytes, but not on the thymocytes.

Activation of murine T-suppressor lymphocytes by group A streptococcal and staphylococcal pyurogenic exotoxins

The effect of group A streptococcal pyrogenic exotoxin (PE) type C and staphylococcal PE on the in vitro antibody response to sheep erythrocytes was studied in cultures of mouse spleen cells. Both exotoxins suppressed the day 4 direct plaque-forming cell response when added to the cultures. The maximum suppression was obtained with 1.0 or 0.1 ng of toxin per culture, and the suppressive effect was reversed by addition of gangliosides to the cultures at the same time as the exotoxins. Preincubation of T lymphocytes for 4 days with either exotoxin resulted in the generation of a suppressor cell population, which produced dose-dependent suppression of the direct plaque-forming cell response when added to fresh sheep eyrthrocyte-activated splenocytes. The suppression obtained was not reversed by gangliosides indicating toxin carry-over was not responsible for the effect. B cells, preincubated with exotoxin, failed to suppress the direct plaque-forming cell response of fresh erythrocyte-activated spleen cells.