Severe group A streptococcal infections associated with a toxic shock-like syndrome and scarlet fever toxin A

Invasive Group a Streptococcal Soft Tissue Infection and the Streptococcal Toxic Shock Like Syndrome

A recent increase in the number of patients with severe group a streptococcal soft tissue infections and the streptococcal toxic shock like syndrome (stsls) in Edmonton sparked the interest to review eight cases that occurred between March 1991 and December 1993, including two patients after cosmetic surgery. These cases were felt to be sporadic and not linked. Four of the eight patients (age range 25 to 64 years), including one patient following upper blepharoplasties, developed invasive infection without shock. These patients presented one to seven days after the initiating event with only mild fever, but severe pain and localized erythema and swelling in the affected area which progressed quickly with the formation of bullae. Two streptococcal specimens were serotyped as M1 and contained streptococcal pyrogenic exotoxins (spe) a and B. Management included surgical debridement, penicillin, and clindamycin (interferes with M-protein and toxin production). All four patients recovered. The other four patients, including one patient following rhytidectomy, (age range 45 to 83 years) were much more ill and developed stsls. They rapidly developed septic shock within 12 to 24 h and progressed to multiorgan involvement despite surgical debridement. One streptococcal specimen was serotyped as M1 and positive for spe a and B, another specimen as M12 and positive for spe B, and another specimen as M-nontypable and positive for spe B. Two patients died within five days of presentation. The other two patients recovered following lengthy hospitalization, reconstructive surgery and rehabilitation.

Hepatitis C infection, cryoglobulinemia, and vasculitic neuropathy. Treatment with interferon alfa: case report and literature review

A patient with mononeuropathy multiplex, hepatitis C viral infection, and mixed cryoglobulinemia had axonal degeneration by EMG and vasculitis of the epineurial vessels on sural nerve biopsy. There was no evidence of viral particles in the nerve by immunofluorescence. Treatment with interferon alfa improved the patient's symptoms and cleared the hepatitis C viral RNA and cryoglobulins from the serum.

Superantigenic characteristics of mouse mammary tumor viruses play a critical role in susceptibility to infection in mice

Mouse mammary tumor viruses (MMTV) are retroviruses that induce mammary carcinomas. An interesting feature of these viruses is the superantigen (SAg) encoded in an open reading frame within the 3' long terminal repeat. The mechanism by which ingestion of milk-borne virus results in infection of the host mammary tissue remains incompletely understood. However, a working model has been proposed in which the interaction between viral SAg, T-cell receptor and MHC class II I-E facilitates viral replication and hence infectivity. In this review we summarize current studies demonstrating the role of SAg stimulation in susceptibility to MMTV infection.

Expression of the Arp protein, a member of the M protein family, is not sufficient to inhibit phagocytosis of Streptococcus pyogenes

Many Streptococcus pyogenes immunoglobulin-binding proteins have structural similarities to the antiphagocytic M protein, including the well-known C repeats. One of these molecules is the immunoglobulin A-binding protein Arp, which is expressed by a serotype 4 strain for which no antiphagocytic M protein has yet been described. We expressed Arp4 in an S. pyogenes strain from which the structural gene for the M protein has been deleted and found that Arp4 is not sufficient to inhibit phagocytosis.

Streptococcal toxic-shock syndrome: spectrum of disease, pathogenesis, and new concepts in treatment

Since the 1980s there has been a marked increase in the recognition and reporting of highly invasive group A streptococcal infections with or without necrotizing fasciitis associated with shock and organ failure. Such dramatic cases have been defined as streptococcal toxic-shock syndrome. Strains of group A streptococci isolated from patients with invasive disease have been predominantly M types 1 and 3 that produce pyrogenic exotoxin A or B or both. In this paper, the clinical and demographic features of streptococcal bacteremia, myositis, and necrotizing fasciitis are presented and compared to those of streptococcal toxic-shock syndrome. Current concepts in the pathogenesis of invasive streptococcal infection are also presented, with emphasis on the interaction between group A Streptococcus virulence factors and host defense mechanisms. Finally, new concepts in the treatment of streptococcal toxic-shock syndrome are discussed.

Correlation between serum TNF alpha and IL6 levels and severity of group A streptococcal infections

The multiorgan failure syndrome caused by group A streptococci (GAS) designated streptococcal toxic shock syndrome (STSS) is believed to be mediated by cytokines induced by superantigens. In order to study the relationship between superantigen production, cytokine levels in patient sera, and clinical GAS manifestation we examined acute-phase sera and strains from 25 patients with GAS bacteremia. The patients had various disease manifestations, including STSS (44%), erysipelas (28%), septicemia (24%), wound infections (16%), and pneumonia (12%). Serotype T1M1 dominated, representing 56% of the isolates, but also strains of other serotypes were identified. The strains were found to produce the streptococcal pyrogenic exotoxins (Spe) A, B, and F, as determined by immuno-blot analyses. There was no difference in amounts of toxin produced between strains isolated from patients with different manifestations of disease. Levels of TNF alpha, IL1 alpha, IL6, IL8, and IFN gamma in acute-phase sera were determined by use of ELISA and RIA assays. The analyses showed higher levels of IL6 in sera from patients with STSS than in sera from patients with bacteremia without shock. TNF alpha was elevated in sera from patients with STSS, as compared to sera from patients with uncomplicated pharyngotonsillitis. No increase in the levels of IL1 alpha, IL8, and IFN gamma could be found in the patient sera and there was no difference in the level of those cytokines between the various patient categories.

Group A streptococci efficiently invade human respiratory epithelial cells

Although infection by group A streptococci is a model of extracellular mucosal pathogenesis, these organisms can be associated with highly invasive infections resulting in sepsis and shock. Over the last 6 yr this species has renewed its reputation as a significant cause of sepsis and has piqued interest in the mechanism by which some strains are better able to breach mucosal barriers to gain access to the bloodstream than are others. An internalization assay was developed on the basis of resistance of intracellular streptococci to penicillin and gentamicin. Experiments showed that stationary-phase, as opposed to logarithmic-phase, bacteria are efficiently internalized and can persist in cultured human cells. Electron microscopy confirmed that streptococci were contained within intracellular vacuoles. Various strains of streptococci revealed significant differences in their capacity to be internalized. Two type M1 streptococci isolated from blood infections were internalized at frequencies equal to those reported for Salmonella and Listeria monocytogenes and greater than the frequency of a clonal variant from a case of pharyngitis.

Superantigenic properties of the group A streptococcal exotoxin SpeF (MF)

Streptococcal pyrogenic exotoxin F (SpeF), previously referred to as mitogenic factor, is a newly described potent mitogen produced by group A streptococci. To investigate whether this protein belongs to the family of microbial superantigens, we analyzed the cellular and molecular requirements for its presentation to T cells and compared it with the known streptococcal superantigen pyrogenic exotoxin A (SpeA) and the nonspecific polyclonal T-cell mitogen phytohemagglutinin (PHA). SpeF and SpeA were efficiently presented by autologous antigen-presenting cells (APCs) and an allogeneic B lymphoma cell line, Raji. In contrast, the monocytic cell line U937, which does not express major histocompatibility complex (MHC) class II molecules, failed to present SpeF as well as SpeA but supported the response to PHA. Thus, the presentation of SpeF by APCs was class II dependent but not MHC restricted. The requirement for HLA class II was further supported by the ability of anti-HLA-DQ monoclonal antibody to block the SpeF-induced proliferative response by 75 to 100%. Paraformaldehyde (PFA) fixation of autologous APCs resulted in an impaired ability of SpeF and SpeA to induce optimal T-cell proliferation. In contrast, fixation of Raji cells did not affect the induced proliferation. The stimulatory effect of PHA remained unaffected by both the use of PFA-fixed APCs and the addition of the HLA class II-specific monoclonal antibodies. The addition of a supernatant enriched in interleukin 1 and interleukin 6 to fixed autologous APCs resulted in an increased SpeF-induced response; thus, the impairment was not due to a requirement for processing, but, rather, costimulatory factors produced by metabolically active APCs were needed. SpeF was found to preferentially activate T cells bearing V beta 2, 4, 8, 15, and 19, as determined by quantitative PCR. The data presented clearly show that SpeF is a superantigen. We also studied the prevalence of the speF gene in clinical isolates by Southern blot analyses, and the gene could be detected in 42 group A streptococcal strains, which represented 14 serotypes.

Comparative study of cytokine release by human peripheral blood mononuclear cells stimulated with Streptococcus pyogenes superantigenic erythrogenic toxins, heat-killed streptococci, and lipopolysaccharide

The differences between toxic or septic shocks in humans during infections by streptococci and gram-negative bacteria remain to be fully characterized. For this purpose, a quantitative study of the cytokine-inducing capacity of Streptococcus pyogenes erythrogenic (pyrogenic) exotoxins (ETs) A and C, heat-killed S. pyogenes bacteria, and Neisseria meningitidis endotoxin (lipopolysaccharide [LPS]) on human peripheral blood mononuclear cells (PBMC) and monocytes has been undertaken. The levels of interleukin-1 alpha (IL-1 alpha), IL-1 beta, IL-6, IL-8, tumor necrosis factor alpha (TNF-alpha), and TNF-beta induced by these bacterial products and bacteria were determined by using cell supernatants. The capacity of ETs to elicit the monocyte-derived cytokines IL-1 alpha, IL-1 beta, IL-6, and TNF-alpha was found to depend on the presence of T lymphocytes, because of the failure of purified monocytes to produce significant amounts of these cytokines in response to ETs. PMBC elicited large amounts of these cytokines, as well as IL-8 and TNF-beta, with an optimal release after 48 to 96 h. The most abundant cytokine produced in response to ETA was IL-8. In contrast to the superantigens ETA and ETC, LPS and heat-killed streptococci stimulated the production of significant amounts of IL-1 alpha, IL-1 beta, IL-6, and TNF-alpha, with optimal production after 24 to 48 h in monocytes, indicating no significant involvement of T cells in the process. ETs, but neither LPS nor streptococci, were potent inducers of TNF-beta in PBMC. This study outlines the differences in the pathophysiological features of shock evoked by endotoxins and superantigens during infection by gram-negative bacteria and group A streptococci, respectively. The production of TNF-alpha was a common pathway for LPS, streptococcal cells, and ETs, although cell requirements and kinetics of cytokine release were different.

Necrotising fasciitis due to group A streptococci in western Norway: incidence and clinical features

During November, 1992, to May, 1994, 13 patients were treated at Haukeland University Hospital, Norway, for necrotising fasciitis due to group A beta-haemolytic streptococci. 3 patients died, 1 before admission. Mucoid group A streptococci were isolated from affected tissue (12 patients) and/or blood (5). Strains from 11 patients were serotype M-1 (5 patients), M-3 (2), M-6 (2), M-28 (1), and M-untypable (T-1, opacity factor negative) (1). For the 12 patients admitted alive, the following preoperative events were recorded: 8 had clinical signs of shock with systolic blood pressure of 90 mm Hg or less, 8 had impaired renal function, and 7 had biochemical markers of disseminated intravascular coagulation. At least 6 patients fulfilled the criteria for streptococcal toxic shock syndrome. Preoperative C-reactive protein was substantially raised ( > 200 mg/L) in 10 patients. The 12 patients were given high doses of antibiotics and were operated on with aggressive debridement of necrotic skin and fascia, 7 of them within 24 h of admission. The increasing incidence of necrotising fasciitis in western Norway reflects the resurgence of invasive group A streptococcal infections documented in Scandinavia since 1987. The high case-fatality rate can be reduced by early diagnosis and aggressive surgery combined with adequate antibiotic therapy.

Rapid detection of hyaluronic acid capsules on group A streptococci by buoyant density centrifugation

One of the virulence factors of group A streptococci is the hyaluronic acid polysaccharide capsule. A rapid method for ascertaining the status of the capsule phenotype in Streptococcus pyogenes is described. Bacteria with a capsule have a lower buoyant density than acapsular or hyaluronidase-treated cells. Early log phase cultures were underlaid with 65% Percoll and centrifuged at 500-1000 g for 5 min. Upon visual examination, encapsulated cells were observed at the interface, whereas acapsular cells appeared in the pellet. Cultures that produced at least 7 micrograms/ml of hyaluronic acid per A600 unit of cells were detected at the interface; this level of polysaccharide is only about 0.5%-4% of that found for most mucoid strains. Therefore, this procedure can detect capsules around strains that do not appear to be encapsulated by light microscopy or do not possess mucoid colony morphology. Furthermore, this method reduces dependence on other expensive assays that use labile radioactive reagents to detect hyaluronic acid.

Production and partial characterization of monoclonal antibodies against erythrogenic toxins type A and C from Streptococcus pyogenes

Hybridoma cell lines producing monoclonal antibodies against streptococcal erythrogenic toxins type A and C were established from fusions of immunized BALB/c mice splenocytes with P3X63-Ag8.653 myeloma cells. Six MAbs recognize ETA and 11 MAbs bind to ETC. Two MAbs (designated ETA-2 and ETC-10) were produced in ascitic fluid and further characterized. ETA-2 (IgG2a) binds to ETA with an affinity constant of 1.8 x 10(10) M-1 and ETC-10 (IgG1) binds to ETC with an affinity constant of 3.5 x 10(9) M-1. The specificities of the MAbs were evaluated by ELISA and immunoblotting. Both MAbs ETA-2 and ETC-10 are useful in developing specific double-sandwich ELISAs, in which the MAbs were used as solid-phase capture antibodies for the quantitative determinations of ETA and ETC.

New pathogens in pneumonia

It appears that many commonly recognized syndromes such as the ARDS may well be caused by agents that have only recently emerged as respiratory pathogens. HPS represents one such entity. It appears likely that the increasing pressure of antibiotic use as well as the reemergence of certain pathogens will continue to challenge the clinician. Paramount to the identification and treatment of unusual pneumonias will be the degree with which an effort is made to make an etiologic diagnosis through sputum examination, transtracheal aspirate, bronchoscopy, or lung biopsy. Although pneumococcal pneumonia is the most common community-acquired pneumonia seen by practicing physicians, in all likelihood from time to time a physician will encounter pneumonia caused by one of the unusual pathogens described in this article or else by an altogether new pathogen.

Similar cytokine induction profiles of a novel streptococcal exotoxin, MF, and pyrogenic exotoxins A and B

The cytokine production induced by a newly discovered streptococcal exotoxin, MF, and the pyrogenic exotoxins SpeA and SpeB was determined by in vitro stimulation of peripheral blood mononuclear cells (PBMCs) obtained from healthy blood donors. The induction and kinetics of interleukin-1 alpha (IL-1 alpha), IL-1 beta, IL-1 receptor antagonist, IL-2, IL-3, IL-4, IL-5, IL-6, IL-8, IL-10, gamma interferon, tumor necrosis factor alpha (TNF-alpha), TNF-beta, and granulocyte-macrophage colony-stimulating factor were studied at the single-cell level by use of cytokine-specific monoclonal antibodies and intracellular immunofluorescent juxtanuclear staining. The cytokine-producing cells, with the exception of IL-1-expressing cells, had a characteristic morphology generated by the accumulation of cytokines in the Golgi organelle. MF, SpeA, and SpeB induced a massive gamma interferon and TNF-beta response in 10 to 16% of the PBMCs after 48 to 96 h of cell stimulation. In contrast, IL-2 and TNF-alpha production was detected in only 1 to 3% of the PBMCs. The induction of a lymphocyte TH2 phenotype response, including production of IL-3, IL-4, IL-5, and IL-10, was weak. However, the monokines, IL-1 alpha, IL-1 beta, IL-1 receptor antagonist, and IL-8, were consistently found and gradually produced, peaking at 24 h in approximately 5 to 8% of the PBMCs. MF showed extensive cytokine- and proliferation-inducing capacities equal to those of SpeA and SpeB, which suggests that MF is also a superantigen. A marked interindividual variation could be noted both in the proliferative response and in the cytokine induction of lymphocytes isolated from different individuals, which may be one explanation for the varying clinical severity noticed during group A streptococcal infections.

Dual infections with Staphylococcus aureus and Streptococcus pyogenes causing toxic shock syndrome. Possible synergistic effects of toxic shock syndrome toxin 1 and streptococcal pyrogenic exotoxin C

We describe a 35-year-old woman with clinical, microbiologic, and serologic findings suggesting that the patient developed toxic shock syndrome as a result of dual infections caused by toxin-producing strains of Staphylococcus aureus and Streptococcus pyogenes. Certain aspects of the pathogenesis of this toxin-related syndrome are reviewed.

Accessory cell ability of Langerhans cells for superantigen is resistant to ultraviolet-B light

We examined the effects of ultraviolet-B (UVB) irradiation on the accessory cell ability of Langerhans cells (LC) to induce a T-cell response to a superantigen, staphylococcal enterotoxin B (SEB). The ability of LC-enriched epidermal cells (LC-EC) to evoke a T-cell response to SEB was retained at the doses of UVB (up to 40 mJ/cm2) that profoundly affected the antigen-presenting function of LC-EC for a hapten, trinitrophenyl (TNP), and a protein antigen, conalbumin. Thus, the LC accessory function for superantigens is more resistant to UVB irradiation than that for ordinary antigens. This UVB resistance is presumably due to no requirement of antigen processing for superantigens as chemically fixed or chloroquine-treated LC-EC still retained their ability to induce T-cell responses to SEB. Higher doses of UVB (more than 60 mJ/cm2) reduced the accessory cell ability of LC-EC for SEB up to 50% of control. The addition of monoclonal antibodies against adhesion molecules between LC and T cells to the culture resulted in a substantial suppression of the T-cell response to SEB induced by nonirradiated LC-EC, while the UVB-irradiated LC-EC-induced T-cell response was not significantly blocked with these monoclonal antibodies. This suggested that the reduction of LC ability for superantigen by high doses of UVB is at least partly due to the impairment of adhesion molecules on LC by UVB irradiation.

Use of CD4 lymphocyte count to predict long-term survival free of AIDS after HIV infection

OBJECTIVE

To estimate the probability of remaining free of AIDS for up to 25 years after infection with HIV by extrapolation of changes in CD4 lymphocyte count.

DESIGN

Cohort study of subjects followed from time of HIV seroconversion until 1 January 1993. Creation of model by using extrapolated linear regression slopes of CD4 count to predict development of AIDS after 1993.

SETTING

Regional haemophilia centre in teaching hospital.

SUBJECTS

111 men with haemophilia infected with HIV during 1979-85. Median length of follow up 10.1 years, median number of CD4 counts 17. The model was not fitted for three men because only one CD4 measurement was available.

MAIN OUTCOME MEASURES

Development of AIDS.

INTERVENTIONS

From 1989 prophylaxis against candida and Pneumocystis carinii pneumonia and antiretroviral drugs when CD4 count fell below 200 x 10(6)/l.

RESULTS

44 men developed AIDS up to 1 January 1993. When AIDS was defined as a CD4 count of 50 x 10(6)/l the model predicted that 25% (95% confidence interval 16% to 34%) would survive for 20 years after seroconversion and 18% (11% to 25%) for 25 years. Changing the CD4 count at which AIDS was assumed to occur did not alter the results. Younger patients had a higher chance of 20 year survival than older patients (32% (12% to 52%) for those aged < 15, 26% (14% to 38%) for those aged 15-29, and 15% (0% to 31%) for those aged > or = 30).

CONCLUSIONS

These results suggest that even with currently available treatment up to a quarter of patients with HIV infection will survive for 20 years after seroconversion without developing AIDS.

Severe community acquired pneumonia associated with a desquamating rash due to group A beta-haemolytic streptococcus

In recent years frequent and severe infections due to group A beta-haemolytic streptococci have been recognised with increasing frequency. Group A streptococcal pneumonia remains a rare disease occurring sporadically in contrast to epidemics in the past. The association between group A streptococcal pneumonia and a desquamating skin rash typical of scarlet fever has rarely been reported.

Molecular characterization and phylogenetic distribution of the streptococcal superantigen gene (ssa) from Streptococcus pyogenes

A striking increase in the frequency and severity of invasive infections caused by Streptococcus pyogenes has occurred in recent years. Among these diseases is streptococcal toxic-shock-like syndrome (TSLS), a condition characterized by fulminant soft-tissue destruction and multiorgan failure. Streptococcal superantigen (SSA), a superantigen isolated from a TSLS-inducing, serotype M3 S. pyogenes strain, has recently been identified. We here describe the cloning, sequencing, and phylogenetic distribution of the SSA structural gene. The 783-bp open reading frame encodes a predicted 260-amino-acid protein that is similar in size to several other bacterial superantigens. The deduced sequence of the mature protein is 60.2% identical to that of staphylococcal enterotoxin B but only 49% identical to that of streptococcal pyrogenic exotoxin A. Southern blot and PCR analysis of 138 group A streptococcal strains representing 65 M protein serotypes and 15 nontypeable isolates identified ssa in 68 strains from 10 distinct clonal lineages. All ssa-positive clones expressed SSA. Of the two clones associated with TSLS, the ET 2-M3 lineage, but not the ET 1-M1 lineage, carried the SSA gene. Further analysis of the ET 2-M3 lineage found evidence for temporal variation in ssa association. Contemporary ET 2-M3 disease isolates had ssa, but two older isolates of this clone recovered in 1910 and 1920 lacked the gene. The clonal and temporal distribution patterns of ssa suggest a relatively recent acquisition of this superantigen-encoding gene by the ET 2-M3 lineage, perhaps by horizontal transfer and recombination.

Serious group A beta-hemolytic streptococcal infections complicating varicella

STUDY OBJECTIVE

To alert practicing emergency physicians to an important and possibly increasing relationship between life-threatening group A beta-hemolytic streptococcal (GABHS) infections and children recovering from varicella.

DESIGN

A case series of six patients managed from January through March 1993.

SETTING

A university-affiliated pediatric specialty emergency department.

TYPE OF PARTICIPANTS

Six previously healthy immunocompetent children between 1 and 5 years of age seen in our ED over a nine-week period.

RESULTS

Six children had onset of varicella two days to two weeks before developing a serious life-threatening GABHS infection. Children presented with clinical symptoms of invasive GABHS infection with bacteremia (one patient); streptococcal toxic shock syndrome with negative blood culture (two), pneumonia with pleural effusion and streptococcal toxic shock syndrome (one), pneumonia with pleural effusion (one), and pyomyositis of the thigh (one). Four of six patients required intensive care admissions and aggressive support of vital signs. All six survived.

CONCLUSION

Emergency physicians should be aware of the association between varicella and serious GABHS infections and be prepared to recognize and aggressively manage serious complications should they occur.

Lymphokine production induced by streptococcal pyrogenic exotoxin-A is selectively down-regulated by pooled human IgG

The influence of pooled human IgG preparations for intravenous use (IVIg) on cytokine production induced by streptococcal pyrogenic exotoxin-A (SPE-A) was studied at the single-cell level using cytokine-specific monoclonal antibodies and indirect immunofluorescence or immunohistochemical staining. Mononuclear cells from healthy adult blood donors were stimulated with SPE-A alone or in the presence of IVIg. IVIg was added either prior to stimulation or 24 h after initiation of cultures, in an attempt to evaluate whether IVIg treatment could influence an already established systemic streptococcal disease. Cells were harvested after 48 or 72 h of culture and stained for the following cytokines: interleukin(IL)-1 alpha, IL-1 beta, IL-1ra, IL-6, IL-8, IL-2, tumor necrosis factor interferon(IFN)-gamma and TNF-alpha and TNF-beta and granulocyte macrophage-colony-stimulating factor. Stimulation with SPE-A lead to extensive lymphokine and monokine production. With the addition of IVIg prior to stimulation there was a strong reduction of blast transformation and an almost complete inhibition of lymphokine production, in particular in the synthesis of IFN-gamma and TNF-beta while the synthesis of IL-1 and IL-8 was either unaffected or increased. Adding IVIg 24 h after SPE-A stimulation also resulted in reduced blast transformation and decreased synthesis of IFN-gamma and TNF-beta. These results indicate an immunomodulatory potential by IVIg on streptococcally induced T cell activation and lymphokine production.

Syndromes with renal failure and shock

Renal failure occurs commonly in children with shock, coagulopathy and multi-organ failure. Successful management of these patients requires not only management of the renal failure, but recognition and treatment of the underlying process. In addition to common and well-recognised causes of renal failure and shock, such as Gram-negative sepsis, there are a number of syndromes which are either less well recognised or confined to specific geographic locations. This article reviews the clinical and epidemiological features of the syndromes with shock and renal failure, focusing on the more recently recognised syndromes such as staphylococcal and streptococcal toxic shock syndrome, haemorrhagic shock and encephalopathy syndrome and viral haemorrhagic fevers.

Fulminant septicaemia due to Streptococcus milleri infection in a previously healthy adult

A 59-year-old previously healthy female developed purulent pharyngitis leading rapidly to neck cellulitis, septicaemic shock and fatal cardiac arrest despite appropriate antibiotic therapy. Streptococcus milleri was isolated from a submandibular abscess, cellulitic neck tissue and blood cultures. Fulminant septicaemia due to this group of organisms is relatively uncommon and usually occurs in the immunocompromised or otherwise chronically unwell.

Echocardiographic images in unusual hemorrhagic pericarditis

Two children with acute symptomatic pericardial effusion had unusual echocardiographic findings. In each case, the pericardial effusion was hemorrhagic. Echocardiography displayed numerous linear bands coursing across the pericardial space. Recognition of this characteristic image may predict that an acute effusion is loculated, and perhaps hemorrhagic, so that surgical drainage will offer the most definitive treatment. Knowledge gained during management of the first patient was used to anticipate treatment of the second patient, influencing the choice to perform pericardiocentesis in the catheterization laboratory and to alert surgical colleagues of the anticipated need for surgical drainage.

Detection and nucleotide sequence analysis of the speC gene in Swedish clinical group A streptococcal isolates

The production of pyrogenic exotoxins SpeA, SpeB, and SpeC by group A streptococci has been associated with streptococcal toxic shock syndrome. Several epidemiological studies using DNA hybridization and PCR analysis have been performed in attempts to correlate one or several of the toxins with streptococcal toxic shock syndrome. The results reveal great variation in the occurrence of the speA and speC genes among clinical isolates. In this study, we show that the speC gene could be detected by nested PCR in five Swedish T1M1 strains isolated from patients infected with group A streptococci as well as in three Norwegian T1M1 isolates, previously reported to lack speC as determined by dot blot hybridization. To verify the identities of the amplified products, the nucleotide sequences of the PCR fragments from one Swedish T1M1 strain and from the toxin reference strain NY5 were determined. The nucleotide sequences showed that the amplified products were speC and of allele type C2, on the basis of the nucleotides in positions 438 and 456. However, one additional base pair substitution was found in NY5 at position 147 and in the Swedish isolate at position 157, which resulted in nonsynonymous amino acid changes. Thus, these speC genes represent two new allelic variants.

Optical immunoassay for streptococcal pharyngitis: evaluation of accuracy with routine and mucoid strains associated with acute rheumatic fever outbreak in the intermountain area of the United States

The Strep A OIA (BioStar, Inc., Boulder, Colo.) rapid detection system is an intriguing technology that utilizes an immunoassay relying on changes in reflected light to directly detect group A streptococcal antigen from specimens. In this evaluation, 424 routine pediatric throat specimens and 20 simulated oropharyngeal specimens with added mucoid (M type 3, 18) strains were cultured and tested by the Strep A OIA. The respective sensitivities and specificities were as follows: Strep A OIA versus enhanced broth culturing, 84.2 and 95.7%; and streptococcus-SXT agar (BBL Microbiology Systems, Cockeysville, Md.) culturing versus enhanced broth culturing, 82.9 and 98.6%. The Strep A OIA is an 8-min, technologist-friendly, accurate technique with an 89.4% agreement with traditional culturing.

Effects on virulence of mutations in a locus essential for hyaluronic acid capsule expression in group A streptococci

Mucoid or highly encapsulated strains of group A streptococci have been associated both with unusually severe infections and with acute rheumatic fever. Previously, we described an acapsular mutant, TX4, derived from a mucoid M-type 18 strain of a group A streptococcus by transposon mutagenesis (M. R. Wessels, A. E. Moses, J. B. Goldberg, and T. J. DiCesare, Proc. Natl. Acad. Sci. USA 88:8317-8321, 1991). We now report studies further characterizing strain TX4 as well as an additional acapsular mutant, TX72. Strain TX4 was found to contain a 9.5-kb deletion of chromosomal DNA adjacent to the site of transposon Tn916 insertion. Cloned chromosomal DNA from TX4 flanking the transposon insertion site was used as a probe to demonstrate the presence of homologous regions in 11 of 11 wild-type group A streptococcal strains of various M protein types. A second acapsular mutant, TX72, had a single transposon insertion and had no apparent deletion of chromosomal DNA. The Tn916 insertion in TX72 was mapped to the hasA locus (encoding hyaluronate synthase), which lies within the chromosomal region deleted in TX4. Strain TX72 was avirulent in mice and sensitive to phagocytic killing in vitro. Transduction of either the insertion-deletion mutation from TX4 or the simple insertion mutation from TX72 to a type 24 group A streptococcus strain also resulted in loss of capsule expression, demonstrating that a homologous region of the chromosome controls capsule expression in another serotype of group A streptococci. We conclude that the hyaluronic acid capsule plays an important role in virulence and that a region of the chromosome essential for capsular polysaccharide expression is conserved among diverse group A streptococcal strains.

Streptococcal toxic shock-like syndrome: case report and review of the literature

Streptococcal toxic shock-like syndrome is a newly recognized complication of infections by group A beta-haemolytic streptococci (GABHS). Previous reports of this syndrome have originated from developed countries, predominantly North American and Europe. This report describes a 5-year-old Saudi child who developed this syndrome in association with streptococcal pharyngitis. It indicates that the recent resurgence of severe GABHS diseases is a global phenomenon.

Coley's toxins, tumor necrosis factor and cancer research: a historical perspective

As far back as the 1700s, it was recorded that certain infectious disease processes could exert a beneficial therapeutic effect upon malignancy. Most prominent among the numerous deliberate efforts made to take advantage of these observations was that of a pioneering New York surgeon, William B. Coley, active career 1891-1936. Using a bacterial vaccine to treat primarily inoperable sarcoma. Coley accomplished a cure rate of better than 10%. This review examines the history of these efforts and presents a discussion of their corresponding relevance to present day immunotherapy.

Bilateral pulmonary abscesses caused by Streptococcus pyogenes: diagnostic importance of fiberoptic bronchoscopy

A patient with bilateral pulmonary abscesses caused by Streptococcus pyogenes is described. This bacterium is an uncommon cause of pneumonia. Metastatic foci of infection, e.g. abscess formation, may follow bacteremic spread of S. pyogenes. However, such complications are rare and the occurrence of bilateral pulmonary abscesses has not been described earlier. In the present case the diagnosis was established by fiberoptic bronchoscopy with bronchial washing.

Superantigenic staphylococcal exotoxins induce T-cell proliferation in the presence of Langerhans cells or class II-bearing keratinocytes and stimulate keratinocytes to produce T-cell-activating cytokines

Several staphylococcal toxins are among a growing number of immunostimulatory molecules called "superantigens" because of their ability, when presented by appropriate major histocompatibility complex class II+ accessory cells, to activate essentially all T cells bearing particular T-cell receptor V beta gene segments. We have examined the ability of murine epidermal Langerhans cells and/or keratinocytes to act as accessory cells in the T-cell response to the superantigens staphylococcal enterotoxin B and exfoliative toxin, also known as epidermolysin. Purified murine splenic T cells were stimulated with staphylococcal enterotoxin B or exfoliative toxin in the presence of Langerhans cells--enriched epidermal cells from normal mice or epidermal cells isolated from mice pretreated with recombinant interferon-gamma, a procedure that induces the expression of major histocompatibility complex class II molecules on keratinocytes. The data show that both Langerhans cells and class II-bearing keratinocytes can act as accessory cells in the T-cell response to staphylococcal enterotoxin B and exfoliative toxin. We also observed that both human and murine keratinocytes cultured in the presence of staphylococcal enterotoxin B or exfoliative toxin produce increased amounts of cytokine(s) capable of stimulating thymocytes and D10 cells, and that this toxin activity is independent of the level of expression of class II on keratinocytes. Studies by enzyme-linked immunosorbent assay showed that staphylococcal enterotoxin B stimulates keratinocytes to produce tumor necrosis factor-alpha but not interleukin-1, suggesting tumor necrosis factor-alpha and perhaps other cytokines are responsible for the T-cell proliferative activity. These results demonstrate that two distinct epidermal constituents (i.e. Langerhans cells and keratinocytes) can serve as accessory cells in the responses of T cells to superantigenic bacterial toxins. It is possible that such toxins contribute to the pathogenesis of a variety of skin diseases by either locally activating T cells bearing particular V beta genes and/or enhancing keratinocyte production of immunomodulatory cytokines.

Rapid detection of Streptococcus pyogenes in pediatric patient specimens by DNA probe

A chemiluminescent DNA probe test (Group A Streptococcus Direct Test; Gen-Probe, Inc., San Diego, Calif.) for rapid, direct detection of cRNA of Streptococcus pyogenes in throat swabs was compared with conventional culture and identification techniques. Throat swabs from 277 patients suspected of having streptococcal pharyngitis were examined. By DNA probe alone, 10 specimens were positive, 51 were positive by both assays, and 8 were positive by culture alone. Thus, DNA probe sensitivity, specificity, and positive and negative predictive values were 86, 95, 84, and 96%, respectively. Including an indeterminate category, sensitivity, specificity, and positive and negative predictive values were 89, 96, 86, and 97%, respectively. After discrepancy testing, these values for the raw data improved to 90, 98, 93, and 97%, respectively. None of the 24 specimens that grew non-S. pyogenes beta-hemolytic streptococci in culture were positive by the DNA probe. Because mucoid S. pyogenes strains are more virulent than nonmucoid strains, 24 isolates were retrospectively tested with the DNA probe to ensure that both types would be detected equally well. Isolates were examined in pure cultures as well as mixed with representative normal oral flora. There was no statistical difference in detection of any of the four groups. Group A Streptococcus Direct Test is a rapid, sensitive, and specific test for S. pyogenes.

Toxic shock syndrome as the AIDS-defining diagnosis

Toxic shock syndrome (TSS) has been infrequently reported as a complication of AIDS. We present the case of a 24-year-old man, previously unknown to be positive for the human immunodeficiency virus, presenting in septic shock. The literature on TSS in AIDS is reviewed and the association between the two diseases is presented.

Staphylococcus aureus as a cause of perianal dermatitis

Perianal dermatitis has been reported to be caused by group A beta-hemolytic Streptococcus. We present a case caused by Staphylococcus aureus. A clinical clue pointing to this organism was the presence of satellite pustules. Identifying the pathogen in perianal dermatitis is therapeutically important, as oral penicillin VK will not be effective if S. aureus is the true cause. Other streptococcal and staphylococcal cutaneous infections may exhibit overlapping clinical features, including scarlet fever, impetigo, toxic shock syndrome, and cellulitis.