Association of high levels of serum antibody to staphylococcal toxic shock antigen with nasal carriage of toxic shock antigen-producing strains of Staphylococcus aureus

Phagocyte subsets and lymphocyte clonal deletion behind ineffective immune response to Staphylococcus aureus

Lack of known mechanisms of protection against Staphylococcus aureus in humans is hindering development of efficacious vaccines. Preclinical as well as clinical data suggest that antibodies play an important role against S. aureus. For instance, certain hypogammaglobulinaemic patients are at increased risk of staphylococcal infections. However, development of effective humoral response may be dampened by converging immune-evasion mechanisms of S. aureus. We hypothesize that B-cell proliferation induced by staphylococcal protein A (SpA) and continuous antigen exposure, without the proper T-cell help and cytokine stimuli, leads to antigen-activated B-cell deletion and anergy. Recent findings suggest an important role of type I neutrophils (PMN-I) and conventionally activated macrophages (M1) against S. aureus, while alternatively activated macrophages (M2) favour biofilm persistence and sepsis. In addition, neutrophil-macrophage cooperation promotes extravasation and activation of neutrophils as well as clearance of bacteria ensnared in neutrophil extracellular traps. Activation of these processes is modulated by cytokines and T cells. Indeed, low CD4(+) T-cell counts represent an important risk factor for skin infections and bacteraemia in patients. Altogether, these observations could lead to the identification of predictive correlates of protection and ways for shifting the balance of the response to the benefit of the host through vaccination.

Microarray-based identification of human antibodies against Staphylococcus aureus antigens

PURPOSE

The mortality rate of patients with Staphylococcus aureus infections is alarming and urgently demands new strategies to attenuate the course of these infections or to detect them at earlier stages.

EXPERIMENTAL DESIGN

To study the adaptive immune response to S. aureus antigens in healthy human volunteers, a protein microarray containing 44 S. aureus proteins was developed using the ArrayStrip platform technology.

RESULTS

Testing plasma samples from 15 S. aureus carriers and 15 noncarriers 21 immunogenic S. aureus antigens have been identified. Seven antigens were recognized by antibodies present in at least 60% of the samples, representing the core S. aureus immunome of healthy individuals. S. aureus-specific serum immunoglobulin G (IgG) levels were significantly lower in noncarriers than in carriers specifically anti-IsaA, anti-SACOL0479, and anti-SACOL0480 IgGs were found at lower frequencies and quantities. Twenty-two antigens present on the microarray were encoded by all S. aureus carrier isolates. Nevertheless, the immune system of the carriers was responsive to only eight of them and with different intensities.

CONCLUSION AND CLINICAL RELEVANCE

The established protein microarray allows a broad profiling of the S. aureus-specific antibody response and can be used to identify S. aureus antigens that might serve as vaccines or diagnostic markers.

Bacteriophage as effective decolonising agent for elimination of MRSA from anterior nares of BALB/c mice

BACKGROUND

Nasal carriers not only pose serious threat to themselves but also to the community by playing an active role in the dissemination of serious and life threatening S. aureus especially MRSA strains. The present study focuses on the use of broad spectrum lytic phage as decolonising agent. In addition, the combined use of lytic phage with mupirocin has also been investigated as an effective decolonising regimen. The effect of phage on the adherence, invasion and cytotoxic effect of MRSA strains on nasal epithelial cells was studied in an ex-vivo model of cultured murine nasal epithelial cells. This was followed by demonstration of therapeutic potential of phage along with mupirocin in decolonising the nares of BALB/c mice using a nasal model of MRSA colonisation.

RESULTS

Phage was able to significantly reduce the in vitro adherence, invasion and cytotoxicity of MRSA 43300 as well as other clinical MRSA strains on murine nasal epithelial cells as compared to untreated control. Also, the frequency of emergence of spontaneous mutants decreased to negligible levels when both the agents (phage and mupirocin) were used together.

CONCLUSION

Phage MR-10, given along with mupirocin showed an additive effect and the combination was able to effectively eradicate the colonising MRSA population from the nares of mice by day 5.

Patient nostril microbial flora: individual-dependency and diversity precluding prediction of Staphylococcus aureus acquisition

The potential role of a patient's resident microbial flora in the risk of acquiring multiresistant bacteria (MRB) during hospitalization is unclear. We investigated this role by cross-sectional study of 103 patients at risk of acquisition of Staphylococcus aureus (SA), resistant (MRSA) or not (MSSA) to methicillin, recruited in four French hospitals. The flora was analysed by an exhaustive culture-based approach combined with molecular and/or mass-spectrometry-based identification, and SA strain typing. Forty-three of the 53 SA-negative patients at entry were followed for up to 52 weeks: 19 (44.2%) remained negative for SA and 24 (55.8%) became positive, including 19 (79%) who acquired an MSSA, four (17%) who acquired an MRSA and one who acquired both (4%). Fifty-one different species were identified among the 103 patients, of which two, Corynebacterium accolens and Staphylococcus haemolyticus (p = 0.02-0.01), were more prevalent in the absence of SA. However, the same number of patients carrying or not these two species acquired an MSSA/MRSA during follow-up, regardless of antibiotic treatment received. Clustering analysis showed that the microbial flora was highly specific to each patient, and not predictive for acquisition of MSSA/MRSA or not. Patient-specific microbial resident flora is not predictive of SA acquisition.

Emerging infectious disease: what are the relative roles of ecology and evolution?

The increasing threat of infectious diseases in humans has renewed interest in factors leading to the emergence of new diseases and the re-emergence of familiar diseases. Examples of seemingly novel diseases currently spreading in human populations include HIV, dengue hemorrhagic fever and Lyme disease; drug-resistant forms of well-known diseases such as tuberculosis are also increasing. The problem of disease emergence also extends to other animal and plant populations. In most current epidemics, ecological factors (e.g. migration, climate, agricultural practices) play a more significant role in disease emergence than evolutionary changes in pathogens or hosts. Evolutionary biologists and ecologists have much to offer to the development of strategies for the control of emerging diseases.

Staphylococcus aureus harbouring Enterotoxin A as a possible risk factor for multiple sclerosis exacerbations

BACKGROUND

Staphylococcus aureus may produce superantigens that can non-specifically activate CD4(+) cells to potentially target the myelin basic protein.

OBJECTIVE

This study examined the association between individuals with multiple sclerosis (MS) and colonization with S. aureus harbouring superantigens.

METHODS

Nasal swabs were collected from non-MS subjects and patients with MS who had not experienced a relapse in the past six months (MS stable group) and who had suffered a relapse within 30 days of study recruitment (MS exacerbation group). S. aureus was isolated from the anterior nares of participants following standard procedures and staphylococcal superantigen genes (sea, seb, and tsst-1) were detected using standard laboratory PCR techniques.

RESULTS

The study enrolled 204 patients, 80 in the non-MS and MS stable groups and 44 patients in the MS exacerbation group. Overall, 27.0% of patients were colonized with S. aureus with no significant differences identified between study groups. Amongst individuals colonized with S. aureus, the prevalence of sea was significantly greater in the MS exacerbation versus non-MS study group (p < 0.05; odds ratio 7.9; 95% confidence interval 1.2-49.5).

CONCLUSIONS

The ability to rapidly screen patients for the presence of S. aureus producing sea may serve as a useful marker of a potential MS exacerbation.

Vaccination as infection control: a pilot study to determine the impact of Staphylococcus aureus vaccination on nasal carriage

BACKGROUND

There is a critical need for an effective Staphylococcus aureus vaccine for the prevention of staphylococcal disease. In this study, we investigated the impact of S. aureus conjugate vaccine comprised of capsular polysaccharides 5 and 8 (CP5, CP8) on nasal colonization with S. aureus.

METHODS

Healthy adults recruited from one academic medical center to participate in a lot consistency trial of StaphVAX (S. aureus capsular polysaccharide 5 and 8 conjugate vaccine) were assessed for S. aureus nasal colonization at two weekly points prior to vaccination and again at six weeks post-vaccination. Serum anti-capsular antibody titers to CP5 and CP8 were obtained prior to vaccination and 42 days post-vaccination and measured by ELISA.

RESULTS

Thirty of 88 enrolled subjects (34%) had S. aureus isolated from at least one of the pre-immunization cultures. Of these, 20 were termed persistent carriers due to two positive cultures one week apart; 19 of the 20 were evaluable at Day 42. Baseline anti-CP8 concentrations were higher in persistent carriers of CP8+ S. aureus; however, baseline anti-CP5 levels were not significantly higher in individuals persistently colonized with CP5+ S. aureus. Statistically significant rises in antibody concentrations were noted after vaccination. At Day 42, 14 of 19 persistent carriers remained colonized; 5 subjects did not have evidence of S. aureus colonization. Ten additional subjects were positive for S. aureus at Day 42 who were not persistently colonized at baseline. Serum antibody concentrations were not statistically different between those with persistent carriage vs. those that lost carriage or those with newly acquired carriage.

CONCLUSIONS

Immune responses to vaccine were brisk and comparable in subjects with or without persistent colonization. Despite a substantial rise in anti-CP5 and anti-CP8 antibody concentrations post-vaccination, S. aureus nasal colonization rates did not significantly change.

Molecular pathogenesis of Staphylococcus aureus infection

S. aureus has evolved a comprehensive strategy to address the challenges posed by the human immune system. The emergence of community-associated methicillin-resistant S. aureus (CA-MRSA) infections in individuals with no predisposing conditions suggests an increased pathogenicity of the bacterium, which may be related to acquisition of novel genetic elements. Remarkably, despite an abundance of research, the underlying cause of the epidemic is not known. Here, the various strategies used by S. aureus to evade obstacles laid out by the human host during colonization and infection were reviewed. The controversies surrounding MRSA research were described, and how acquisition of the novel genes could explain the increased incidence and severity of CA-MRSA diseases was described.

Anti-staphylococcal humoral immune response in persistent nasal carriers and noncarriers of Staphylococcus aureus

BACKGROUND

Persistent carriers have a higher risk of Staphylococcus aureus infections than noncarriers but a lower risk of bacteremia-related death. Here, the role played by anti-staphylococcal antibodies was studied.

METHODS

Serum samples from 15 persistent carriers and 19 noncarriers were analyzed for immunoglobulin (Ig) G, IgA, and IgM binding to 19 S. aureus antigens, by means of Luminex technology. Nasal secretions and serum samples obtained after 6 months were also analyzed.

RESULTS

Median serum IgG levels were significantly higher in persistent carriers than in noncarriers for toxic shock syndrome toxin (TSST)-1 (median fluorescence intensity [MFI] value, 11,554 vs. 4291; P < .001) and staphylococcal enterotoxin (SE) A (742 vs. 218; P < .05); median IgA levels were higher for TSST-1 (P < .01), SEA, and clumping factor (Clf) A and B (P < .05). The in vitro neutralizing capacity of anti-TSST-1 antibodies was correlated with the MFI value (R(2) = 0.93) and was higher in persistent carriers (90.6% vs. 70.6%; P < .05). Antibody levels were stable over time and correlated with levels in nasal secretions (for IgG, R(2) = 0.87; for IgA, R(2) = 0.77).

CONCLUSIONS

Antibodies to TSST-1 have a neutralizing capacity, and median levels of antibodies to TSST-1, SEA, ClfA, and ClfB are higher in persistent carriers than in noncarriers. These antibodies might be associated with the differences in the risk and outcome of S. aureus infections between nasal carriers and noncarriers.

The role of nasal carriage in Staphylococcus aureus infections

Staphylococcus aureus is a frequent cause of infections in both the community and hospital. Worldwide, the increasing resistance of this pathogen to various antibiotics complicates treatment of S aureus infections. Effective measures to prevent S aureus infections are therefore urgently needed. It has been shown that nasal carriers of S aureus have an increased risk of acquiring an infection with this pathogen. The nose is the main ecological niche where S aureus resides in human beings, but the determinants of the carrier state are incompletely understood. Eradication of S aureus from nasal carriers prevents infection in specific patient categories-eg, haemodialysis and general surgery patients. However, recent randomised clinical trials in orthopaedic and non-surgical patients failed to show the efficacy of eliminating S aureus from the nose to prevent subsequent infection. Thus we must elucidate the mechanisms behind S aureus nasal carriage and infection to be able to develop new preventive strategies. We present an overview of the current knowledge of the determinants (both human and bacterial) and risks of S aureus nasal carriage. Studies on the population dynamics of S aureus are also summarised.

Detection of specific antibodies in cord blood, infant and maternal saliva and breast milk to staphylococcal toxins implicated in sudden infant death syndrome (SIDS)

The common bacterial toxins hypothesis of sudden infant death syndrome (SIDS) is that nasopharyngeal bacterial toxins can trigger events leading to death in infants with absent/low levels of antibody that can neutralise the toxins. The aim of this study was to investigate nasopharyngeal carriage of Staphylococcus aureus and determine levels of immunity in the first year of life to toxic shock syndrome toxin (TSST-1) and staphylococcal enterotoxin C (SEC). Both toxins have been implicated in SIDS cases. Seventy-three mothers and their infants (39 males and 34 females) were enrolled onto the study. The infants had birth dates spread evenly throughout the year. In infants, S. aureus carriage decreased significantly with age (P<0.001). Between 40% and 50% of infants were colonised with S. aureus in the first three months of life and 49% of the isolates produced one or both of the staphylococcal toxins. There was a significant correlation between nasopharyngeal carriage of S. aureus in mothers and infants in the three months following the birth (P<0.001). Carriage of S. aureus in infants and their mothers was not significantly associated with levels of antibody to TSST-1 or SEC in cord blood, adult saliva or breast milk. Infants colonised by S. aureus had higher levels of salivary IgA to TSST-1 than infants who were culture negative. Analysis of cord blood samples by a quantitative ELISA detected IgG bound to TSST-1 and SEC in 95.5% and 91.8% of cases respectively. There was a marked variation in levels of maternal IgG to both TSST-1 and SEC among cord blood samples. Maternal age, birth weight, and seasonality significantly affected the levels of IgG binding to TSST-1 or SEC. Analysis of infant saliva samples detected IgA to TSST-1 and SEC in the first month after birth; 11% of samples tested positive for salivary IgA to TSST-1 and 5% for salivary IgA to SEC. By the age of two months these proportions had increased to 36% and 33% respectively. More infants who used a dummy tested positive for salivary IgA to TSST-1 compared to infants who did not use a dummy. Levels of IgA to TSST-1 and SEC detected in the breast-milk samples varied greatly among mothers. There was a trend for infants receiving breast milk with low levels of antibody to TSST-1 or SEC to have higher levels of salivary antibody to the toxins. In conclusion, passive immunity to toxins implicated in SIDS cases varies greatly among infants. Infants are able to mount an active mucosal immune response to TSST-1 and SEC in the first month of life.

Staphylococcal superantigens and T cell expansions in Wegener's granulomatosis

In Wegener's granulomatosis (WG), a form of autoimmune systemic vasculitis, chronic carriage of Staphylococcus aureus constitutes a risk factor for the development of exacerbations. Circulating T cells in this disease are persistently activated, suggesting the presence of a chronic stimulus. A causal link between chronic carriage of S. aureus and chronic T cell activation in WG is conceivable, because S. aureus produces superantigens (SAg), which are potent T cell stimulators. Superantigenic stimulation of T cells results in expansion of T cell subsets expressing SAg-binding T cell receptor V-beta (Vbeta) chains. In the present study we hypothesized that in WG the presence of staphylococcal SAg is accompanied by expansion of SAg-reacting T cell subsets. We tested our hypothesis in a cross-sectional and a longitudinal study in which the association between seven staphylococcal SAg genes [typed by poplymerase chain reaction (PCR)], eight SAg-binding Vbeta chains and four SAg-non-binding Vbeta chains (assessed by flow-cytometry) was assessed. Both studies showed that T cell expansions were present at a significantly higher rate in WG patients than in healthy individuals, but were not associated with the presence of either S. aureus or its SAg. Moreover, T cell expansions were generally of small extent, and did not appear simultaneously in both CD4 and CD8 subsets. We conclude that in WG S. aureus effects its supposed pathogenic function by a mechanism other than superantigenic T cell activation.

Recurrent nonmenstrual toxic shock syndrome: clinical manifestations, diagnosis, and treatment

We report 3 cases of recurrent nonmenstrual toxic shock syndrome (TSS) and review the clinical manifestations, diagnosis, and treatment. The primary sites of infection were the genital tract (in a patient who underwent cesarean delivery), the upper respiratory tract, and a breast abscess. In all 3 patients, the initial illness was not recognized to be TSS; only after development of recurrent illness with desquamation was this diagnosis entertained. Strains of Staphylococcus aureus that were isolated from 2 patients produced TSS toxin-1, whereas the third strain produced staphylococcal enterotoxin B. All 3 patients lacked antibody to the implicated toxins at the time of presentation with recurrent illness. Nonmenstrual TSS can occur in a variety of clinical settings and may be recurrent. The presence of desquamation during a febrile, multisystem illness could suggest this diagnosis and should prompt the clinician to obtain appropriate cultures for S. aureus.

Staphylococcus aureus nasal carriage in rheumatoid arthritis: antibody response to toxic shock syndrome toxin-1

OBJECTIVE

To determine the prevalence of Staphylococcus aureus nasal carriage and to compare antibody responses to two superantigens, staphylococcal toxic shock syndrome toxin-1 (TSST-1) and staphylococcal enterotoxin A (SEA), in rheumatoid arthritis patients and normal subjects.

METHODS

88 rheumatoid arthritis patients and 110 control subjects were cultured for nasal carriage of S aureus; 62 isolates were bacteriophage typed. Twenty five patients and 11 spouses were tested for antibodies to TSST-1, SEA, and sonicate extracts of Bacteroides fragilis and Escherichia coli; 19 patients were HLA-DR typed.

RESULTS

50% of patients and 33% of normal subjects were S aureus carriers. Bacteriophage typing of isolates suggested significant differences between strains isolated from the two groups. Patients showed higher IgG (P = 0.0025) and IgA (P = 0.0372) antibody levels to TSST-1 than normal spouses and these responses were not related to rheumatoid factor titres or HLA-DR type.

CONCLUSION

When compared to normals, rheumatoid arthritis patients more often carry S aureus in their nasal vestibule, carry a distinct subpopulation of S aureus strains, and have higher average antibody levels to TSST-1.

Characteristics of Staphylococcus aureus strains isolated from clinical and non-clinical human sources in Trinidad: susceptibility to bacteriophages and antimicrobial agents, and toxigenicity

The susceptibility of Staphylococcus aureus strains isolated from human clinical and non-clinical sources in Trinidad to bacteriophages and antimicrobial agents was determined. The ability of the strains to produce enterotoxins and toxic shock syndrome toxin-1 (TSST-1) was also investigated. Of the 554 strains tested, 454 (81.8%) were susceptible to international phage set (IPS) phages with strains isolated from bacteruria (57.1%) and bacteremia (53.3%) having a low sensitivity compared to isolates from aspirates (87.3%) and anterior nares (97.4%). All sources combined, strains were most susceptible to phages belonging to several groups (mixed). Overall, 419 (75.6%) strains were resistant to one or more of nine antimicrobial agents tested. Resistance to penicillin was most prevalent, with 413 (74.5%) strains found to be resistant. Prevalence of resistance to tetracycline, gentamicin, oxacillin, cefuroxime and ciprofloxacin was 5.1%, 2.0%, 0.7%, 0.4% and 0.4%, respectively. Of the 554 strains tested, 307 (55.4%) produced staphylococcal enterotoxins A (SEA), B (SEB), C (SEC) and D (SED) singly or in combination. Strains recovered from high vaginal swabs were least enterotoxigenic (40.0%) as compared to umbilical infection isolates which were most enterotoxigenic (78.9%). TSST-1 was produced by 95 (19.0%) out of 499 strains tested, with isolates from bacteruria found to be most toxigenic (33.3%). It was concluded that the S. aureus strains tested were highly susceptible to bacteriophages and antimicrobial agents (except penicillin) and that enterotoxigenic and TSST-1 producers were widespread and have an aetiologic potential.

Toxic shock syndrome toxin-1 (TSST-1) production and phage susceptibility of Staphylococcus aureus strains from human vaginas and anterior nares in Trinidad

The carriage rates of Staphylococcus aureus in the anterior nares of children and women as well as in the vagina of women were determined. The ability of strains of S. aureus to produce toxic shock syndrome toxin-1 (TSST-1) and their susceptibility to phages of the international phage set (IPS) for human strains were also investigated. Of 200 women studied, the carriage rate of S. aureus in high vaginal swabs and anterior nares swabs was 57 (28.5%) and 73 (36.5%), respectively. Eight (4.0%) and 16 (8.0%) patients were carriers of TSST-1-producing strains in their vaginas and anterior nares, respectively. Amongst the 220 children sampled, 100 (45.5%) were carriers of S. aureus in their anterior nares, with 51 (23.2%) children being positive for TSST-1 producing strains. Overall, of the 233 strains of S. aureus isolated from all sources 176 (75.5%) were typable and 75 (32.2%) were positive for TSST-1 production. For strains from anterior nares, isolates from children were more susceptible (81.2%) to IPS phages than those from women (67.1%) but the difference was not significant (P > or = 0.05; chi 2). Forty-five (76.3%) of 59 strains of vaginal origin were typable. The frequency of production of TSST-1 amongst strains isolated from children, i.e. (50.5% (51 of 101), was significantly higher (P > or = 0.001; chi 2) than that found for isolates from women's anterior nares (21.9%) and vagina (13.6%). S. aureus was recovered from both the anterior nares and vaginal swabs of 11 patients sampled. The phage patterns of 5 of the 6 typable pairs of isolates established their relatedness suggesting that the same strains colonized the anterior nares and vagina of each of these patients. It was concluded that the carriage of TSST-1-producing strains of S. aureus in the anterior nares and vagina of women was much lower than that detected in children's anterior nares and that the risk of vaginal toxic shock syndrome (TSS) in Trinidadian women was relatively low. Susceptibility of strains was high to IPS phages. Epidemiological significance was attributed to the finding that the same strains of S. aureus colonized the anterior nares and vaginas of some women.

Toxic shock syndrome: a complication of continent urinary diversion

Toxic shock syndrome, a potentially lethal multisystem illness that usually affects menstruating women, is characterized by the acute onset of fever, hypotension, skin and mucous membrane changes, nausea, vomiting, diarrhea, myalgias, capillary leak, vascular collapse and multiorgan dysfunction. The disease is mediated by toxin produced by distinct strains of Staphylococcus aureus. We describe a case in which a toxin producing strain growing in a continent urinary diversion produced toxic shock syndrome.

Toxic shock syndrome toxin 1 (TSST-1) production by staphylococci isolated from goats and presence of specific antibodies to TSST-1 in serum and milk

The ability of staphylococcal strains isolated from different anatomical sites in 133 healthy goats to produce toxic shock syndrome toxin 1 (TSST-1) and the presence of antibodies to this toxin in serum and milk were studied. The enzyme-linked immunosorbent assay method was used to detect both the toxin and the presence of antibodies. Of a total of 342 staphylococcal strains studied, 86 (25.2%) were found to produce TSST-1. Specific antibodies to TSST-1 were found in the serum of 57 (42.9%) of the animals studied and the milk of 63 (47.4%) of the animals. These results suggest that goats are frequently in contact with staphylococci that produce TSST-1, a toxin usually associated with Staphylococcus aureus strains isolated from cases of toxic shock syndrome in humans.

Detection of antibodies to staphylococcal enterotoxins in the serum and milk of healthy goats

A study was made of the presence of antibodies (Ab) to staphylococcal enterotoxins A to E (SEA-SEE) in the serum and milk of 133 healthy goats, using a competitive ELISA method. Antibodies to some enterotoxins were detected in 83 sera (62.4%) and in 41 (30.8%) milk samples. In serum, antibodies to all SE types were detected, the most frequent being antibodies to SEA (24.8%). Milk contained antibodies to SEA, SEB and SEC, the latter being the most frequent (24.8%). A statistical study was performed to correlate the number of animals harbouring antibodies to a given enterotoxin with the presence in these animals of staphylococci producing that enterotoxin.

Binding of type-I and type-II collagens to Staphylococcus aureus strains isolated from patients with toxic shock syndrome compared to other staphylococcal infections

Toxic shock syndrome toxin-1 (TSST-1) producing strains of Staphylococcus aureus isolated from 18 patients with toxic shock syndrome (TSS) and from 56 patients with other diagnoses were compared for capacity to interact with various serum and connective tissue proteins. TSS associated isolates showed significantly stronger binding of Type-I collagen (Cn-I) and Cn-II than non-TSS strains, in a particle agglutination assay (PAA) as well as in 125I labelled Cn uptake experiments. 125I Cn-IV binding, was similar between the two groups, whereas in PAA, a stronger interaction was observed for non-TSS than TSS associated strains. The median binding of 125I Cn to TSS-associated strains were 52.2 (Cn-I), 30.6 (Cn-II) and 20.0 (Cn-IV) compared to 20.0 (Cn-I), 14.4 (Cn-II) and 24.4 (Cn-IV) values of non-TSS strains. A saturation with 125I Cn-I and Cn-II binding was established for TSS (30 min) and non-TSS (15 min) strains. 125I Cn-IV binding reached a saturation in 10 min and 90 min with TSS and non-TSS strains respectively. Finally, the binding profiles of TSS associated and non-TSS strains to fibronectin, fibrinogen, laminin and IgG did not differ in both PAA and radioisotope assays. In scanning electron microscopy, cells of TSS associated strains bound to the reprecipitated native Cn-I fibrils. In contrast, most cells of non-TSS strains were localized to the distal end or were trapped between the Cn fibrils.(ABSTRACT TRUNCATED AT 250 WORDS)

The nasopharyngeal bacterial flora in the sudden infant death syndrome

The nasopharyngeal bacterial flora in babies who had died of the sudden infant death syndrome (SIDS) (n = 46) and in healthy infants aged 2 weeks to 6 months (n = 46) is described. Of those who had died, 41.3% carried Staphylococcus aureus (95% confidence limits: 27.3-55.3%) compared with 28.3% of healthy infants (95% confidence limits: 15.3-41.3%). The isolation rate of streptococci was 78.3% in cases (95% confidence limits: 66.4-90.2%) and 32.6% in healthy infants (95% confidence limits: 19.1-46.1%) (significant difference P less than 0.0001). Enterobacteria were isolated from 45.6% of cases (95% confidence limits: 31.2-60%) but only 2.2% of healthy infants (95% confidence limits 0-6.4%) (significant difference, P less than 0.0001). These results indicate a disordered nasopharyngeal flora in SIDS. They also provide baseline data for investigating the hypothesis that common bacterial toxins are involved in the pathogenesis of SIDS.

Ovine-associated Staphylococcus aureus protein with immunochemical similarity to toxic shock syndrome toxin 1

A toxic shock syndrome toxin 1 (TSST-1) antibody-binding protein produced by an ovine-associated strain of Staphylococcus aureus was examined. The protein showed total identity to TSST-1 by immunodiffusion analysis. Western blots (immunoblots) of proteins separated by isoelectric focusing revealed that the TSST-1 antibody-binding protein had a pI of 8.6 rather than 7.0, the pI of standard TSST-1.

Antibodies against toxic shock syndrome toxin no. 1 (TSST-1) in Poland

A total of 174 sera from healthy Polish individuals of different age groups were tested for TSST-1 antibody by the micro-ELISA method. Over 90% of sera contained the antibody with titres equal to above 1:10(2), even in children and adolescents. The data suggest that the majority of the Polish population acquires TSST-1-antibody during early childhood, whereas a small portion of the population seems to remain anti-TSST-1-negative.

Synergism of Candida albicans and delta toxin producing Staphylococcus aureus on mouse mortality and morbidity: protection by indomethacin

Twelve Staphylococcus aureus strains, six positive and six negative for delta-toxin production, were studied for synergistic effects on mouse mortality and morbidity when combined with Candida albicans and inoculated intraperitoneally (i.p.). S. aureus strains producing delta-toxin were found to exhibit a relatively great synergistic decrease (between near 10(3)-10(5)-fold) in LD50 (dose necessary to kill 50% of exposed animals in five days) when combined with a nonlethal dose of C. albicans and injected i.p. S. aureus strains which did not produce delta showed less of a synergistic effect with C. albicans (10-10(2)-fold drop in LD50). A synergistic effect on mortality could also be produced when animals were dually injected with C. albicans and sterile growth filtrates from the delta-toxin producing strains or the purified delta-toxin. The lethal agent in the culture filtrate was, like delta-toxin, sensitive to lecithin and insensitive to heat. Indomethacin protected animals from the C. albicans-filtrate induced death. Blood measurements made following i.p. injection of delta-toxin and C. albicans revealed chemistry changes indicative of shock, kidney and liver damage; delta-toxin alone caused no significant chemistry changes whereas C. albicans alone caused some blood chemistry changes but liver and kidney damage was not indicated. No synergism on mortality was found between C. albicans and purified alpha-toxin or toxic shock syndrome toxin-1.

Association of toxic shock toxin-1 determinant with a heterologous insertion at multiple loci in the Staphylococcus aureus chromosome

Most Staphylococcus aureus strains associated with toxic shock syndrome and producing toxic shock syndrome toxin 1 (TSST-1) require tryptophan because of a genetic defect in tryptophan biosynthesis. The association between TSST-1 production and tryptophan auxotrophy was not correlated with the phage type, the colonization site, or the disease status of the patient from whom the isolate came. Protoplast fusion and transformation mapping located the genetic determinant of TSST-1 production (tst) very close to the trp operon in such strains and very close to tyrB in a Trp+ TSST-1+ strain. Southern blot hybridization of ClaI-restricted chromosomal DNA with a tst-specific probe revealed a common homologous segment in all of the Trp+ strains with tst linked to tyrB. These results confirmed that the tst determinant in Trp- strains is located at one site, whereas in Trp+ TSST-1+ strains the determinant is located elsewhere on the S. aureus chromosome. It is suggested that the TSST-1 determinant is associated with the insertion of a transposonlike segment into several sites on the S. aureus chromosome.

Toxic shock syndrome

In the past 10 years, we have learned much about TSS and S. aureus and its toxins. A number of important biologic principles have been reemphasized in this first decade of TSS research: S. aureus is a very complex organism, one not likely to yield quick answers; in vitro observations must always be confirmed in the patient; animal models may not always be reliable replicates of human disease; and epidemiologic associations cannot be equated with causation. Toxic shock is an intricate phenomenon with many interesting scientific facets. Unraveling its mysteries will undoubtedly teach us more about the complex interaction of patients and microorganisms.

Toxic shock syndrome: a review

TSS is a recently described acute febrile illness characterized by hypotension, rash, desquamation, and multisystemic involvement. While most common in menstruating women, TSS also occurs in men and non-menstruating women. It is now known that the disease is caused by one or more toxins produced by the S aureus organism. Treatment of TSS consists primarily of fluid resuscitation and supportive care. Anti-staphylococcal antibiotics are indicated primarily to reduce the rate of recurrence in menstrually related cases. In wound-related TSS, antibiotics are necessary to treat the primary wound infection and to prevent recurrent disease. Currently, the case fatality rate is stable at less than 3% and the major long-term complication of survivors is the risk of recurrence.

Low incidence of toxic shock syndrome in children with staphylococcal infection

Children have frequent staphylococcal infections, and many lack antibody to TSST-1, a toxin associated with the toxic shock syndrome (TSS). To determine why there have been no nonmenstrual cases of TSS reported in children in Utah, the authors tested S. aureus isolated from children for TSST-1 by radial immunodiffusion and sera from other hospitalized children by radioimmunoassay for antibody to TSST-1. TSST-1 was produced by 25% of S. aureus. Fifty-two children had infections with toxin producing strains. None had TSS. The prevalence of presumably protective levels of antibody (greater than or equal to 1:100) was high in newborns (80%), declined until age 2 years and then gradually increased with age. Therefore, there may have been about 20 children with toxigenic infection who lacked protective antibody but did not show the usual features of TSS. We conclude that the rarity of TSS in children is not caused by misdiagnosis, underreporting, or the absence of toxigenic strains or susceptible patients. Additional factors, such as local conditions or duration of carriage, may influence the clinical presentation of infection with TSST-1 producing staphylococci.

[IgG antibodies to toxic shock syndrome toxin-1 (TSST-1) in human sera]

IgG antibodies against toxic shock syndrome toxin-1 (TSST-1) in 2002 human sera were determined using an enzyme-linked immunosorbent assay. The results indicate a very early common exposure to TSST-1 in German males and females. The antibody titers are increasing up to the age of 20. They continue to increase further from the mid-thirties, reaching a peak level in the mid-fifties. Toxic shock syndrome is rarely described in Germany. It is possible, therefore, that most of the infections with TSST-1 producing S. aureus are of a subclinical nature. An atypical, less dramatic course than the commonly known toxic shock syndrome is also discussed.

Antibodies to staphylococcal enterotoxins and toxic shock syndrome toxin 1 in sera of patients and healthy people in Rio de Janeiro, Brazil

Sera from 33 persons with staphylococcal infections and from 37 healthy persons were surveyed for the presence of antibody to staphylococcal enterotoxins A, B, C, D, and E and toxic shock syndrome toxin 1. Thirty-one (93.9%) of the patients and 35 (94.6%) of the control group had antibodies to one or more of the enterotoxins. The numbers of patients with antibody to the enterotoxins were as follows: A, 8; B, 9; C, 7; D, 17; E, 21; and toxic shock syndrome toxin 1, 11. The numbers of healthy individuals with antibody to the enterotoxins were as follows: A, 6; B, 12; C, 8; D, 27; E, 21; and toxic shock syndrome toxin 1, 9.

Encapsulation and capsular types in isolates of Staphylococcus aureus from different sources and relationship to phage types

The relationship of capsular types of Staphylococcus aureus to type of infection, carrier state, and phage type was studied in a collection of 477 isolates from 380 infection sites. Capsular polysaccharides were demonstrated by precipitation and agglutination with 11 monospecific antisera. When only one isolate from each infection was considered, 63% were of type 8 and 16% were of type 5. Of all the isolates tested, over 90% were encapsulated. We did not demonstrate any marked difference in the distribution of capsular types between isolates from the blood stream or purulent processes and isolates from healthy carriers or food. Most isolates from bovine mastitis milk had nontypeable capsules. The capsular type seemed stable in culture, and encapsulation had no apparent influence on susceptibility to phages. Of 27 phage-propagating strains maintained via culture transfer on artificial media over many years, 16 (59%) produced capsules. A striking association between certain phage patterns and capsular types was demonstrated.

Competitive, enzyme-linked immunosorbent assay for toxic shock syndrome toxin 1

We developed a competitive, enzyme-linked immunosorbent assay for the quantitation of toxic shock syndrome toxin 1 (TSST-1). Polyvalent immunoglobulin G from immunized rabbits was used as the capture antibody, and alkaline phosphatase conjugated to purified toxin served as the indicator enzyme. A standard curve was generated with each experiment, from which the concentration of toxin in culture supernatants was extrapolated. The assay was useful for determining toxin concentrations of 0.03 to 0.5 micrograms/ml, which is a substantial, practical improvement over immunodiffusion methods. Staphylococcal enterotoxins A through E were not significantly cross-reactive in the assay, and staphylococcal protein A did not interfere with quantitation of TSST-1. By testing a variety of staphylococcal strains, we found 100% concordance between toxin determinations made with our assay and those made by the investigators from whom the strains were obtained. The competitive, enzyme-linked immunosorbent assay is a highly reproducible, inexpensive means of determining TSST-1 concentrations and may have broad applicability in the field of toxic shock research.

Serological response to toxic shock syndrome toxin in Staphylococcus aureus infected patients and healthy controls

The prevalence of antibodies to Toxic Shock Syndrome Toxin (TSST-1) in a Swedish healthy control population was investigated using an enzyme-linked immunosorbent assay (ELISA). 88% of the control group above the age of 10 showed positive antibody levels as compared to 31% of those who were under 10 years old. These results indicate a very common normal exposure to TSST-1 during early life and also identify the small risk-group of potential TSS-patients. Patients with S. aureus endocarditis and septicemia showed slightly higher antibody levels as compared to the controls (p less than 0.05). The difference was in part due to 3/4 septicemia patients, infected with TSST-1 producing strains, who showed very high antibody levels. None of these 4 patients developed any signs of TSS. 5/5 menstrual associated TSS-patients were negative in the ELISA in serial serum samples as were 3/5 non-menstrual associated TSS-patients. The TSST-1 ELISA is proposed for identifying chiefly young women at risk of acquiring menstrual related Toxic Shock Syndrome.

Effect of toxic shock syndrome toxin 1 on chicken embryos

Staphylococcus aureus strains associated with toxic shock syndrome produce toxic shock syndrome toxin 1 (TSST1). This toxin has a variety of biological effects, including enhanced lethality in rabbits in the presence of sublethal amounts of lipopolysaccharide (LPS). Because chicken embryos are highly susceptible to LPS, the synergistic effect of TSST1 and LPS was examined in this system. Although TSST1 per se had no effect on chicken embryos, it potentiated the lethal effect of LPS. The 50% lethal dose of LPS was greatly reduced in the presence of up to 10 micrograms of TSST1 per ml. However, at high doses of TSST1 (greater than 100 micrograms/ml), no enhanced lethality was observed. The lowest dose of TSST1 tested which potentiated lethality was 10 ng/ml.

Presence of toxic shock toxin in toxic shock and other clinical strains of Staphylococcus aureus

Toxic shock toxin (TST), also known as pyrogenic exotoxin C (Schlievert et al., J. Infect. Dis. 143:509-516, 1981) and staphylococcal enterotoxin F (Bergdoll et al., Lancet i:1017-1021, 1981), was purified from toxic shock strains of Staphylococcus aureus by preparative isoelectric focusing and by chromatofocusing. Neither method produced an absolutely pure protein as determined by silver staining of sodium dodecyl sulfate-acrylamide gels, although chromatofocusing was the better method of the two. Three molecular weight variants of the protein were found in the two toxic shock syndrome strains that were studied, regardless of the purification method that was used. An isoelectric point of 7.15 and molecular weights of 21,400, 22,100, and 23,200 were determined for the different forms of the protein from electrophoresis data. A sedimentation coefficient of 2.3S was determined by sucrose gradient centrifugation, and a Stokes radius of 2 X 10(-7) cm was determined by gel filtration. An average molecular weight of 18,900 for all of the TST forms was calculated from these data by the Stokes-Einstein equation. A survey for TST in 32 control and 46 toxic shock strains of S. aureus by isoelectric focusing and by agarose gel double immunodiffusion with specific rabbit antiserum revealed that the isoelectric focusing method tends to overestimate the number of TST-positive strains because of the detection of non-TST, neutral staphylococcal proteins. Based on immunodiffusion data, the association of TST with toxic shock strains was found to be 100% in vaginal isolates and 62% in non-vaginal isolates. In the control strains, TST was found in 16% of the vaginal strains and 23% of the non-vaginal strains. The value of this toxin as a marker for toxic shock and its relationship to the pathogenesis of this disease are discussed.

Comparative observations of fever and associated clinical hematological and blood biochemical changes after intravenous administration of staphylococcal enterotoxins B and F (toxic shock syndrome toxin-1) in goats

The present investigation was undertaken to examine the characteristics of purified toxic shock syndrome toxin-1 (staphylococcal enterotoxin F) given intravenously to dwarf goats (dose, 0.02 to 20 micrograms kg-1). Rectal temperature, heart rate, rumen motility, plasma zinc and iron concentrations, and certain other blood biochemical and hematological values were studied and compared with the changes seen after intravenous administration of staphylococcal enterotoxin B (dose, 0.02 to 0.5 micrograms kg-1). Similar changes such as fever, tachycardia, inhibition of rumen contractions, drop in plasma zinc and iron concentrations, lymphopenia, and a decrease in serum alkaline phosphatase activity were observed. In contrast to the effects of toxic shock syndrome toxin-1, staphylococcal enterotoxin B induced colic, watery diarrhea with pseudomembranes, hemoconcentration, and a more pronounced increase in blood urea nitrogen. The results obtained demonstrate that (i) in the goat staphylococcal enterotoxin B is much more potent than toxic shock syndrome toxin-1 and (ii) the goat is a useful model to study the gastro-intestinal effects caused by staphylococcal enterotoxin B. The present finding that no clear relationship could be found between the temperature response and the alterations in zinc and iron levels in plasma support the theory that the febrile reactions and the changes in plasma trace metals are mediated by different polypeptides released by activated macrophages.