Purpura Fulminans Due toStaphylococcus aureus

Molecular Epidemiology Clinical Manifestations, Decolonization Strategies, and Treatment Options of Methicillin-Resistant Staphylococcus aureus Infection in Neonates

Preterm and low-birth-weight neonates are particularly susceptible to methicillin-resistant Staphylococcus aureus (MRSA) colonization, whereas MRSA infection is associated with significant neonatal morbidity and mortality globally. The objective of our study was to examine the current body of knowledge about molecular traits, epidemiology, risk factors, clinical presentation, decolonization techniques, and available treatments for MRSA infection in neonates. MRSA strains that predominate in neonatal units, namely healthcare-associated (HA)-MRSA, differ from community-acquired (CA)-MRSA strains in molecular characteristics, toxin synthesis, including Panton-Valentine leukocidin, and resistance to antibiotics. Colonization with MRSA predisposes neonates to infection. The clinical impact of MRSA infection includes bacteremia, sepsis, pneumonia, endocarditis, osteomyelitis, septic arthritis, skin and soft tissue infections, and toxic shock syndrome. To reduce MRSA transmission, colonization, and infection, customized approaches are required, including continuous surveillance of MRSA epidemiology, new techniques for detecting MRSA resistance, and the application of basic preventive measures. Antimicrobial susceptibility monitoring is essential to identify the best empirical antimicrobial treatments. The growing antibiotic resistance of MRSA remains challenging, and vancomycin is still the best option. Further extensive research and surveillance are warranted to explore the genetic diversity and prevalence of MRSA.

Comprehensive Analysis of Purpura Fulminans as an Uncommon Postoperative Complication: A Case Series

BACKGROUND

Acute infectious purpura fulminans (AIPF) is a rare but potentially fatal postoperative complication characterised by rapidly progressing disseminated intravascular coagulation (DIC), widespread purpura, and multi-organ dysfunction. Despite its severe and critical outcomes, the literature on this condition in the postoperative context is limited.

OBJECTIVES

This study aimed to analyse and evaluate the incidence, clinical presentation, laboratory findings, management strategies, and outcomes of postoperative AIPF in patients who underwent various surgical procedures.

METHODS

A retrospective case series was conducted, identifying adult patients diagnosed with AIPF within 30 days post surgery from January 2017 to December 2022. Inclusion was based on the International Classification of Diseases, Tenth Revision (ICD-10) coding for purpura fulminans and DIC. Clinical data, including demographic details, type and duration of surgery, onset of symptoms, laboratory findings, microbiology results, treatment strategies, and outcomes, were collected from electronic medical records. Data analysis included descriptive statistics and differences in survival among surgical subgroups were assessed using Kaplan-Meier survival analysis and the log-rank test.

RESULTS

Seven cases of AIPF were identified, with a mean patient age of 57.1 ± 12.5 years, out of which 71.4% (n = 5) were male. Surgical procedures included vascular (42.9%, n = 3), abdominal (28.6%, n = 2), thoracic (14.3%, n = 1), and orthopaedic (14.3%, n = 1) surgeries. The average surgical duration was 5.2 ± 2.7 hours and the mean onset of AIPF was 3.9 ± 1.9 days postoperatively. Clinically, all patients presented with widespread purpura, fever, hypotension, and multi-organ dysfunction, including renal, hepatic, and respiratory failure. Laboratory findings revealed severe coagulopathy, with a low platelet count, higher levels of D-dimer, prolonged prothrombin time, and activated partial thromboplastin time. Gram-negative bacteria were the most prevalent pathogens, particularly Klebsiella pneumoniae and Escherichia coli (28.6% each), while gram-positive Staphylococcus aureus was isolated in one case (14.3%). Despite comprehensive ICU management, including mechanical ventilation, fluid resuscitation, broad-spectrum antibiotics, and administration of fresh frozen plasma/cryoprecipitate (71.4%, n = 5), the mortality rate was 57.1% (n = 4). The median time to death was 48 hours (IQR = 36-72). The highest mortality was observed in vascular (33.3% survival) and thoracic (0% survival) surgery subgroups. Orthopaedic surgery demonstrated a 100% survival rate.

CONCLUSION

AIPF after surgery is associated with significant morbidity and mortality, particularly following vascular and thoracic procedures. The findings underscore the need for heightened postoperative vigilance, early detection, and aggressive management to improve patient outcomes. Future studies should focus on identifying strategies for risk mitigation and early intervention protocols.

Acute Infectious Purpura Fulminans Complicated by Bacterial Translocation after Rectal Cancer Surgery: A Case Report

The patient was a man in his 80s who had undergone laparoscopic anterior resection for rectal cancer. Bowel obstruction occurred on the third postoperative day but improved with a decompression tube by the fifth postoperative day. A high fever (in the 38 °C range) was also observed. Blood culture tests detected two sets of the gram-negative bacilli Klebsiella aerogenes within 24 h of collection. On the seventh postoperative day, the patient subsequently went into septic shock with disseminated intravascular coagulation (DIC). On the eighth postoperative day, the fingertips and toes became black, and the palms and dorsal surfaces of both feet were dark purple due to peripheral circulatory failure. This suggested acute infectious purpura associated with sepsis (acute infectious purpura fulminans (AIPF)). Intensive care was provided; however, the necrosis of both middle fingers worsened, both middle fingers were gangrenous, and the patient died on the thirtieth postoperative day. AIPF is rarely reported, especially in early-onset cases after elective surgery. We encountered a rare complication of bacterial translocation from postoperative bowel obstruction, leading to AIPF.

Infectious purpura fulminans associated with pneumococcal septicaemia in a patient with unacknowledged functional asplenia

Purpura fulminans (PF) is a life-threatening complication of septic shock that can occur due to disseminated infections with Streptococcus pneumoniae The spleen is an important organ in the immunisation process against encapsulated bacteria. Patients with asplenia, either functional or anatomical, are therefore at increased risk of developing serious infections and complications, such as PF, if infected with such bacteria.This case report presents a woman in her late 40s with unacknowledged functional asplenia who was admitted to the hospital with signs of an acute disseminated infection causing septic shock, signs of disseminated intravascular coagulation and infectious PF. A few days after admission, the blood cultures showed growth of S. pneumoniae With early sepsis treatment, the patient survived although with some complications. Clinical presentation, investigations, differential diagnosis, treatment and outcome are presented. Treatment and early recognition of PF are presented and discussed. Relevant recognition and preventative treatment strategies for patients with asplenia are also reviewed and discussed.This case demonstrates the importance of early recognition and treatment of PF in septic patients and the importance of preventive treatment strategies for patients with asplenia to avoid serious infections and complications.

Case report: Blotchy skin in a puffy neonate: is there a new association?

Introduction

Purpura fulminans in the neonatal population is a rare but potentially life-threatening condition complicated by thrombosis, resultant vital organ necrosis, and gangrene of the extremities. Considering the rapid evolution of the pathogenetic mechanism, an index of suspicion, early identification, and prompt intervention are imperative for improved outcomes. The majority of purpura fulminans cases have an infectious etiology, but it is essential to consider other congenital and acquired causes.

Case description

We present a clinical case of a female neonate to emphasize the correlation between purpura fulminans, congenital chylothorax, involvement of the PAK2 gene, and the occurrence of retinal detachment in both eyes. After draining the congenital chylothorax, the neonate developed purpura fulminans due to a loss of protein C, S, and antithrombin factors, previously not reported in the literature. The purpuric lesions resolved after the administration of fresh frozen plasma. Subsequently, no recurring purpura fulminans lesions were noted following the normalization of the antithrombotic factor levels in the serum. Subsequently, the child also developed retinal detachment in both eyes.

Pediatric Swine Model of Methicillin-Resistant Staphylococcus aureus Sepsis-Induced Coagulopathy, Disseminated Microvascular Thrombosis, and Organ Injuries

Sepsis-induced coagulopathy leading to disseminated microvascular thrombosis is associated with high mortality and has no existing therapy. Despite the high prevalence of Gram-positive bacterial sepsis, especially methicillin-resistant Staphylococcus aureus (MRSA), there is a paucity of published Gram-positive pediatric sepsis models. Large animal models replicating sepsis-induced coagulopathy are needed to test new therapeutics before human clinical trials.

HYPOTHESIS

Our objective is to develop a pediatric sepsis-induced coagulopathy swine model that last 70 hours.

METHODS AND MODELS

Ten 3 weeks old piglets, implanted with telemetry devices for continuous hemodynamic monitoring, were IV injected with MRSA (n = 6) (USA300, Texas Children's Hospital 1516 strain) at 1 × 109 colony forming units/kg or saline (n = 4). Fluid resuscitation was given for heart rate greater than 50% or mean arterial blood pressure less than 30% from baseline. Acetaminophen and dextrose were provided as indicated. Point-of-care complete blood count, prothrombin time (PT), activated thromboplastin time, d-dimer, fibrinogen, and specialized coagulation assays were performed at pre- and post-injection, at 0, 24, 48, 60, and 70 hours. Piglets were euthanized and necropsies performed.

RESULTS

Compared with the saline treated piglets (control), the septic piglets within 24 hours had significantly lower neurologic and respiratory scores. Over time, PT, d-dimer, and fibrinogen increased, while platelet counts and activities of factors V, VII, protein C, antithrombin, and a disintegrin and metalloproteinase with thrombospondin-1 motifs (13th member of the family) (ADAMTS-13) decreased significantly in septic piglets compared with control. Histopathologic examination showed minor focal organ injuries including microvascular thrombi and necrosis in the kidney and liver of septic piglets.

INTERPRETATIONS AND CONCLUSIONS

We established a 70-hour swine model of MRSA sepsis-induced coagulopathy with signs of consumptive coagulopathy, disseminated microvascular thrombosis, and early organ injuries with histological minor focal organ injuries. This model is clinically relevant to pediatric sepsis and can be used to study dysregulated host immune response and coagulopathy to infection, identify potential early biomarkers, and to test new therapeutics.

Staphylococcal Enterotoxin B and C Mutants and Vaccine Toxoids

Three mutants individually of both staphylococcal enterotoxins B and C were prepared by site-specific mutagenesis of enterotoxin amino acids that contact host T lymphocyte immune cell receptor sites (N23A, Q210A, and N23A/Q210A); these amino acids are shared between the two enterotoxins, and mutations reduce the interaction with the variable part of the β-chain of the T lymphocyte receptor. The mutant proteins, as expressed in Staphylococcus aureus RN4220, lacked biological toxicity as measured by the loss of (i) stimulation of rabbit splenocyte proliferation, (ii) pyrogenicity, and (iii) the ability to enhance the lethality of endotoxin shock, compared to wild-type enterotoxins. In addition, the mutants were able to vaccinate rabbits against pyrogenicity, the enhancement of endotoxin shock, and lethality in a pneumonia model when animals were challenged with methicillin-resistant S. aureus. Three vaccine injections (one primary and two boosters) protected rabbits for at least 3.5 months postvaccination when challenged with wild-type enterotoxins (last time point tested). These mutant proteins have the potential to function as toxoid vaccines against these two causes of nonmenstrual toxic shock syndrome (TSS). IMPORTANCE Toxic shock syndrome toxin 1 (TSST-1) and staphylococcal enterotoxins B and C cause the majority of cases of staphylococcal toxic shock syndrome. Previously, vaccine toxoids of TSST-1 have been prepared. In this study, vaccine toxoids of enterotoxins B and C were prepared. The toxoids lost biological toxicity but were able to vaccinate rabbits against lethal TSS.

Functional and Immunological Studies Revealed a Second Superantigen Toxin in Staphylococcal Enterotoxin C Producing Staphylococcus aureus Strains

Staphylococcus aureus is a human and animal pathogen as well as a commensal bacterium. It can be a causative agent of severe, life-threatening infections with high mortality, e.g., toxic shock syndrome, septic shock, and multi-organ failure. S. aureus strains secrete a number of toxins. Exotoxins/enterotoxins are considered important in the pathogenesis of the above-mentioned conditions. Exotoxins, e.g., superantigen toxins, cause uncontrolled and polyclonal T cell activation and unregulated activation of inflammatory cytokines. Here we show the importance of genomic analysis of infectious strains in order to identify disease-causing exotoxins. Further, we show through functional analysis of superantigenic properties of staphylococcal exotoxins that even very small amounts of a putative superantigenic contaminant can have a significant mitogenic effect. The results show expression and production of two distinct staphylococcal exotoxins, SEC and SEL, in several strains from clinical isolates. Antibodies against both toxins are required to neutralise the superantigenic activity of staphylococcal supernatants and purified staphylococcal toxins.

Infective endocarditis: Role of molecular techniques in early diagnosis

Infective endocarditis (IE), a heart valve infection primarily caused by bacteria such as streptococci or staphylococci, causes significant morbidity and mortality. Despite the long-term use of broad-spectrum antimicrobials, the infection is often difficult to manage. The latest diagnostic modalities for IE are discussed in this study. Blood culture use in pathogen identification can lead to loss of precious time as well as generation of false negative reports. The first steps in diagnosis are blood cultures and echocardiography, but molecular techniques can be extremely useful and may be used for an accurate and early diagnosis.

Staphylococcal Enterotoxin C Subtypes Are Differentially Associated with Human Infections and Immunobiological Activities

Staphylococcal enterotoxin C has four subtypes that cause human diseases, designated SEC-1 to -4. This study shows that SEC-2 and SEC-3 are the most toxic subtypes in a rabbit model and are associated with human vaginal infections or colonization in association with another superantigen, toxic shock syndrome toxin 1.

Staphylococcus aureus causes significant infections, responsible for toxic shock syndrome (TSS), hemorrhagic pneumonia, and many other infections. S. aureus secretes virulence factors, which include superantigens such as staphylococcal enterotoxins (SEs). We examined differences in immunobiological activities and disease associations among the four human SEC subtypes. We sequenced the sec gene from 35 human isolates to determine SEC subtypes. Upon finding differences in disease association, we used a [³H]thymidine uptake assay to examine SEC-induced superantigenicity. We also employed a rabbit model of SEC-induced TSS. SEC-2 and SEC-3 were associated with menstrual TSS and vaginal isolates from healthy women, whereas SEC-4 was produced by USA400 isolates causing purpura fulminans and hemorrhagic pneumonia. SEC subtypes differed in potency in a TSS rabbit model and in superantigenicity. There was no difference in superantigenicity when tested on human peripheral blood mononuclear cells. Despite differences, all SECs reacted with polyclonal antibodies raised against the other SEC subtypes. The associations of SEC subtypes with different infections suggest that S. aureus produces virulence factors according to host niches.

IMPORTANCE Staphylococcal enterotoxin C has four subtypes that cause human diseases, designated SEC-1 to -4. This study shows that SEC-2 and SEC-3 are the most toxic subtypes in a rabbit model and are associated with human vaginal infections or colonization in association with another superantigen, toxic shock syndrome toxin 1. SEC-4 is associated with purpura fulminans and hemorrhagic pneumonia. SEC-1 is uncommon. The data suggest that there is some selective pressure for the SEC subtypes to be associated with certain human niches.

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 rash that becomes purpuric, petechial, hemorrhagic, or ecchymotic

Hemorrhagic rashes are observed in a wide variety of conditions, ranging from harmless to life-threatening. This review offers a stepwise approach, which helps limit the possible differential diagnoses based on the clinical manifestations and the clinical picture. The most common and most important conditions, including infectious, coagulation and embolic disorders, vasculitides, and vasculopathies, are briefly reviewed focusing on morphology. Dermatologists often need to distinguish among infectious, reactive, or autoimmune etiologies of the rash and determine if the condition is dangerous or even life-threatening in order to make the right decision. Dermatologic expertise provides vital input in the diagnosis and care of complex interdisciplinary patients, such as those with sepsis, purpura fulminans, and thrombotic thrombocytopenic purpura.

Purpura fulminans manifesting with Staphylococcus aureus endocarditis: a case report

BACKGROUND

Purpura fulminans (PF) is a haematologic emergency that can occur in the setting of severe septic shock. Its pathophysiology is not well-understood; however, some evidence suggests it may be mediated by excessive protein C consumption.

CASE SUMMARY

In this case report, we describe a patient with PF secondary to methicillin-resistant Staphylococcus aureus endocarditis. She presented with severe septic shock and, despite haemodynamic improvement, developed a significant purpuric rash. Diagnostic work-up was notable for severely decreased serum levels of protein C. This patient was successfully treated with protein C concentrate and surgical valve replacement.

DISCUSSION

While PF is rarely associated with S. aureus infection, this presentation may be more frequently encountered among clinicians in the current opioid epidemic. Quick recognition is crucial and a multidisciplinary approach, including intravenous infusion of protein C, may be considered.

Fulminant arterial vasculitis as an unusual complication of disseminated staphylococcal disease due to the emerging CC1 methicillin-susceptible Staphylococcus aureus clone: a case report

BACKGROUND

Staphylococcus aureus has emerged as a leading cause of invasive severe diseases with a high rate of morbidity and mortality worldwide. The wide spectrum of clinical manifestations and outcome observed in staphylococcal illness may be a consequence of both microbial factors and variability of the host immune response.

CASE PRESENTATION

A 14-years old child developed limb ischemia with gangrene following S. aureus bloodstream infection. Histopathology revealed medium-sized arterial vasculitis. The causing strain belonged to the emerging clone CC1-MSSA and numerous pathogenesis-related genes were identified. Patient's genotyping revealed functional variants associated with severe infections. A combination of virulence and host factors might explain this unique severe form of staphylococcal disease.

CONCLUSION

A combination of virulence and genetic host factors might explain this unique severe form of staphylococcal disease.

Staphylococcus aureus Leukocidins Target Endothelial DARC to Cause Lethality in Mice

The pathogenesis of Staphylococcus aureus is thought to depend on the production of pore-forming leukocidins that kill leukocytes and lyse erythrocytes. Two leukocidins, Leukocidin ED (LukED) and γ-Hemolysin AB (HlgAB), are necessary and sufficient to kill mice upon infection and toxin challenge. We demonstrate that LukED and HlgAB cause vascular congestion and derangements in vascular fluid distribution that rapidly cause death in mice. The Duffy antigen receptor for chemokines (DARC) on endothelial cells, rather than leukocytes or erythrocytes, is the critical target for lethality. Consistent with this, LukED and HlgAB injure primary human endothelial cells in a DARC-dependent manner, and mice with DARC-deficient endothelial cells are resistant to toxin-mediated lethality. During bloodstream infection in mice, DARC targeting by S. aureus causes increased tissue damage, organ dysfunction, and host death. The potential for S. aureus leukocidins to manipulate vascular integrity highlights the importance of these virulence factors.

Acute infectious purpura fulminans with Enterobacter aerogenes post-neurosurgery

Acute infectious purpura fulminans (AIPF) is a rare, life-threatening disease commonly caused by Neisseria meningitidis and Streptococcus pneumoniae. Gram-negative rods are rarely involved. We described a case of AIPF associated with Enterobacter bacteremia in a 48-year-old man admitted for subarachnoid hemorrhage treatment. After surgical clipping for intracranial aneurysms, septic shock, multiple organ failure, and extensive purpura on the skin developed. Enterobacter aerogenes bacteremia was detected and AIPF was diagnosed. His condition progressively worsened and he died on day 19. Autopsy showed multiple abscesses and thrombosis in the lung, intestinal tract, and kidney.

Whatever happened to the Shwartzman phenomenon?

Ninety years ago, Gregory Shwartzman first reported an unusual discovery following the intradermal injection of sterile culture filtrates from principally Gram-negative strains from bacteria into normal rabbits. If this priming dose was followed in 24 h by a second intravenous challenge (the provocative dose) from same culture filtrate, dermal necrosis at the first injection site would regularly occur. This peculiar, but highly reproducible, event fascinated the microbiologists, hematologists, and immunologists of the time, who set out to determine the mechanisms that underlie the pathogenesis of this reaction. The speed of this reaction seemed to rule out an adaptive, humoral, immune response as its cause. Histopathologic material from within the necrotic center revealed fibrinoid, thrombo-hemorrhagic necrosis within small arterioles and capillaries in the micro-circulation. These pathologic features bore a striking resemblance to a more generalized coagulopathic phenomenon following two repeated endotoxin injections described 4 yr earlier by Sanarelli. This reaction came to be known as the generalized Shwartzman phenomenon, while the dermal reaction was named the localized or dermal Shwartzman reaction. A third category was later added, called the single organ or mono-visceral form of the Shwartzman phenomenon. The occasional occurrence of typical pathological features of the generalized Shwartzman reaction limited to a single organ is notable in many well-known clinical events (e.g., hyper-acute kidney transplant rejection, fulminant hepatic necrosis, or adrenal apoplexy in Waterhouse-Fredrickson syndrome). We will briefly review the history and the significant insights gained from understanding this phenomenon regarding the circuitry and control mechanisms responsible for disseminated intravascular coagulation, the vasculopathy and the immunopathy of sepsis.

Renal histological findings in a patient with acute renal injury associated with purpura fulminans: a case report

INTRODUCTION

Purpura fulminans (PF) is a rapid progressive thrombotic disease in which hemorrhagic infarction of the skin and disseminated intravascular coagulation (DIC) occurs. It can potentially cause acute kidney injury (AKI). However, there is no description in the medical literature of renal histological findings of PF.

CASE REPORT

A 20-year-old female patient, previously healthy, was admitted to the emergency department (ED) with odynophagia, fever, generalized myalgia and anuria, which evolved with the appearance of purpuric plaques on the face and limbs. She required dialysis on admission. Laboratorial tests showed anemia, leukocytosis, thrombocytopenia, and elevation of lactic dehydrogenase (LDH). The purpuric lesions became bullous with ruptures and then necrotic and erosive, reaching the dermis, subcutaneous tissue and musculature, until bone exposure. There was no improvement with initial antibiotic therapy aimed at the treatment of meningococcemia. Thrombotic microangiopathy (TMA) and PF were then suspected. The patient remained in daily dialysis, requiring plasmapheresis. After sustained improvement of the thrombocytopenia, she underwent renal biopsy, which was not compatible with TMA, characterizing possible PF. A complete recovery of the renal function was achieved and cutaneous sequels were treated with grafts.

CONCLUSION

When thrombotic and hemorrhagic phenomena overlap, obtaining a renal biopsy can be difficult. However, in the presented case, the biopsy allowed the exclusion of AKI caused by TMA, presenting for the first time, histological findings compatible with PF.

Clinical spectrum and short-term outcome of adult patients with purpura fulminans: a French multicenter retrospective cohort study

PURPOSE

Data on purpura fulminans (PF) in adult patients are scarce and mainly limited to meningococcal infections. Our aim has been to report the clinical features and outcomes of adult patients admitted in the intensive care unit (ICU) for an infectious PF, as well as the predictive factors for limb amputation and mortality.

METHODS

A 17-year national multicenter retrospective cohort study in 55 ICUs in France from 2000 to 2016, including adult patients admitted for an infectious PF defined by a sudden and extensive purpura, together with the need for vasopressor support. Primary outcome variables included hospital mortality and amputation during the follow-up period (time between ICU admission and amputation, death or end of follow-up).

RESULTS

Among the 306 included patients, 126 (41.2%; 95% CI 35.6-46.9) died and 180 (58.8%; 95% CI 53.3-64.3) survived during the follow-up period [13 (3-24) days], including 51/180 patients (28.3%, 95% CI 21.9-35.5) who eventually required limb amputations, with a median number of 3 (1-4) limbs amputated. The two predominantly identified microorganisms were Neisseria meningitidis (63.7%) and Streptococcus pneumoniae (21.9%). By multivariable Cox model, SAPS II [hazard-ratio (HR) = 1.03 (1.02-1.04); p < 0.001], lower leucocytes [HR 0.83 (0.69-0.99); p = 0.034] and platelet counts [HR 0.77 (0.60-0.91); p = 0.007], and arterial blood lactate levels [HR 2.71 (1.68-4.38); p < 0.001] were independently associated with hospital death, while a neck stiffness [HR 0.51 (0.28-0.92); p = 0.026] was a protective factor. Infection with Streptococcus pneumoniae [sub-hazard ratio 1.89 (1.06-3.38); p = 0.032], together with arterial lactate levels and ICU admission temperature, was independently associated with amputation by a competing risks analysis.

CONCLUSION

Purpura fulminans carries a high mortality and morbidity. Pneumococcal PF leads to a higher risk of amputation.

TRIALS REGISTRATION

NCT03216577.

Rare presentation of rickettsial infection as purpura fulminans: a case report

BACKGROUND

Purpura fulminans is an acute life-threatening disorder characterized by intravascular thrombosis and hemorrhagic infarction of the skin complicated with disseminated intravascular coagulation. It is commonly seen in acute infections following meningococcal and streptococcal infections. Few cases of purpura fulminans following rickettsial infections have been described in the literature.

CASE PRESENTATION

We report a case of a 55-year-old Sri Lankan woman who presented to Teaching Hospital Peradeniya with a febrile illness, headache, and myalgia that progressed to an erythematous rash starting over the bilateral lover limbs and hands and that became black and necrotic with a few hemorrhagic blebs. She had normocytic anemia, platelet clumps, and monocytosis as well as a deranged clotting profile. The result of immunofluorescence antibody testing for rickettsial immunoglobulin G was strongly positive for Rickettsia conorii with a rise in titer convalescent sera, and a diagnosis of purpura fulminans following rickettsial infection was made. The patient made an excellent recovery with chloramphenicol treatment.

CONCLUSIONS

The treating physician should consider the rare but very treatable condition of rickettsial infection as a differential diagnosis in the etiological diagnostic workup of patients presenting with severe purpuric and hemorrhagic rash with fever.

Fatal endocarditis with methicilin-sensible Staphylococcus aureus and major complications: rhabdomyolysis, pericarditis, and intracerebral hematoma: A case report and review of the literature

BACKGROUND

Over the last decades Staphylococcus aureus (SA) has become the dominant etiology of native valve infective endocarditis, with the community-acquired methicillin-sensible Staphylococcus aureus (CA-MSSA) strains being the prevailing type.

CASE

We report here a case of extremely severe CA-MSSA aortic valve acute endocarditis associated with persistent Staphylococcus aureus bacteremia (SAB) in a previously healthy man and include a literature review.The patient developed severe and rare complications (purpura, purulent pericarditis, intracerebral hematoma, and rhabdomyolysis) through systemic embolism; they required drainage of pericardial empyema and cerebral hematoma, the latter eventually caused a fatal outcome. The strains recovered from sequential blood culture sets and pericardial fluid were MSSA negative for genes encoding for staphylococcal toxic shock syndrome toxin (TSST)-1 and Panton-Valentine leukocidin. C, G, and I enterotoxin genes were detected.

CONCLUSIONS

This case with unusually severe evolution underlines the limited ability of vancomycin to control some MSSA infections, possibly due to potential involvement of SA virulence factors, hence the importance of clinical vigilance for community SAB cases.

Isolation of a new ssDNA aptamer against staphylococcal enterotoxin B based on CNBr-activated sepharose-4B affinity chromatography

Staphylococcus aureus are potent human pathogens possessing arsenal of virulence factors. Staphylococcal food poisoning (SFP) and respiratory infections mediated by staphylococcal enterotoxin B (SEB) are common clinical manifestations. Many diagnostic techniques are based on serological detection and quantification of SEB in different food and clinical samples. Aptamers are known as new therapeutic and detection tools which are available in different ssDNA, dsDNA and protein structures. In this study, we used a new set of ssDNA aptamers against SEB. The methods used included preparation of a dsDNA library using standard SEB protein as the target analyte, affinity chromatography matrix in microfuge tubes, SELEX procedures to isolate specific ssDNA-aptamer as an affinity ligand, aptamer purification using ethanol precipitation method, affinity binding assay using ELISA, aptamer cloning and specificity test. Among 12 readable sequences, three of them were selected as the most appropriate aptamer because of their affinity and specificity to SEB. This study presents a new set of ssDNA aptamer with favorable selectivity to SEB through 12 rounds of SELEX. Selected aptamers were used to detect SEB in infected serum samples. Results showed that SEB c1 aptamer (2 µg SEB/100 nM aptamer) had favorable specificity to SEB (kd  = 2.3 × 10(-11) ). In conclusion, aptamers can be considered as useful tools for detecting and evaluating SEB. The results showed that affinity chromatography was an affordable assay with acceptable accuracy to isolate sensitive and selective novel aptamers. Copyright © 2016 John Wiley & Sons, Ltd.

Animal Models Used to Study Superantigen-Mediated Diseases

Superantigens secreted by Staphylococcus aureus and Streptococcus pyogenes interact with the T-cell receptor and major histocompatibility class II molecules on antigen-presenting cells to elicit a massive cytokine release and activation of T cells in higher numbers than that seen with ordinary antigens. Because of this unique ability, superantigens have been implicated as etiological agents for many different types of diseases, including toxic shock syndrome, infective endocarditis, pneumonia, and inflammatory skin diseases. This review covers the main animal models that have been developed in order to identify the roles of superantigens in human disease.

High prevalence of Panton-Valentine leukocidin (PVL) genes in nosocomial-acquired Staphylococcus aureus isolated from tertiary care hospitals in Nepal

Methicillin-resistant Staphylococcus aureus (MRSA) carrying the important virulence determinant, Panton-Valentine leukocidin (PVL), is an emerging infectious pathogen associated with skin and soft tissue infections as well as life-threatening invasive diseases. In carrying out the first PVL prevalence study in Nepal, we screened 73 nosocomial isolates of S. aureus from 2 tertiary care Nepali hospitals and obtained an overall PVL-positivity rate of 35.6% among the hospital isolates: 26.1% of MRSA and 51.9% of methicillin sensitive S. aureus (MSSA) isolates were found to be positive for the PVL genes. PVL prevalence was not associated with a specific (i) infection site, (ii) age group, or (iii) hospital of origin. It was found to be positively associated with heterogeneous MRSA (73.3%) compared to homogeneous MRSA (3.2%) and MSSA (51.9%); negatively associated with multiresistant MRSA (22%) compared to nonmultiresistant MRSA (60%) and MSSA (51.9%); and positively associated with macrolide-streptogramin B resistance (93.8%) compared to macrolide-lincosamide-streptogramin B resistance (0%) and no-resistance (45.8%) types. Macrolide-streptogramin B resistance was confirmed by the presence of msr(A) gene. Restriction pattern analyses provided evidence to support the circulation of a limited number of clones of PVL-positive MRSA, arguing for the adaptability of these isolates to a hospital setting.

Cloning, expression, crystallization and preliminary X-ray diffraction studies of staphylococcal superantigen-like protein 1 (SSL1)

Staphylococcus aureus produces a family of exotoxins which are structural homologues of superantigens and thus are called staphylococcal superantigen-like proteins (SSLs). Amongst the 14 SSL genes, ssl1 (SAOUHSC_00383) has been cloned in the pQE30 expression vector, overexpressed in Escherichia coli M15 (pREP4) cells and the protein purified to homogeneity. The protein was crystallized using 6% Tacsimate pH 6.0, 0.1 M MES pH 6.0, 25%(w/v) polyethylene glycol 3350, 100 mM NDSB 256 at 298 K by the sitting-drop vapour-diffusion method. The crystals belonged to space group P21, with unit-cell parameters a = 77.9, b = 70.5, c = 126.5 Å, β = 106.2°. X-ray diffraction data were collected and processed to a maximum resolution of 2.5 Å. The crystal contains six molecules in the asymmetric unit.

Pneumococcal sepsis-induced purpura fulminans in an asplenic adult patient without disseminated intravascular coagulation

Acute perturbations in the hemostatic balance of anticoagulation and procoagulation antecede the manifestation of purpura fulminans, a rare syndrome of intravascular thrombosis and hemorrhagic infarction of the skin. Hallmarks include small vessel thrombosis, tissue necrosis and disseminated intravascular thrombosis. The course may be rapidly fulminant resulting in multiorgan failure with thrombotic occlusion of the vasculature, leading to distal extremity ischemia and necrosis. Depletion of protein C (PC) has been emphasized in the pathogenesis. Early intravenous antibiotic administration and hemodynamic support are cornerstones in management. Herein, we report a case of pneumococcal sepsis-induced purpura fulminans limited to the skin in an asplenic adult patient without the development disseminated intravascular coagulation.

Staphylococcal and streptococcal superantigen exotoxins

SUMMARY This review begins with a discussion of the large family of Staphylococcus aureus and beta-hemolytic streptococcal pyrogenic toxin T lymphocyte superantigens from structural and immunobiological perspectives. With this as background, the review then discusses the major known and possible human disease associations with superantigens, including associations with toxic shock syndromes, atopic dermatitis, pneumonia, infective endocarditis, and autoimmune sequelae to streptococcal illnesses. Finally, the review addresses current and possible novel strategies to prevent superantigen production and passive and active immunization strategies.

Molecular analysis of staphylococcal superantigens

Staphylococcal superantigens (SAgs) comprise a large family of exotoxins produced by Staphylococcus aureus strains. These exotoxins are important in a variety of serious human diseases, including menstrual and nonmenstrual toxic shock syndrome (TSS), staphylococcal pneumonia and infective endocarditis, and recently described staphylococcal purpura fulminans and extreme pyrexia syndrome. In addition, these SAg exotoxins are being increasingly recognized for their possible roles in many other human diseases, such as atopic dermatitis, Kawasaki syndrome, nasal polyposis, and certain autoimmune disorders. To clarify the full spectrum of human diseases caused by staphylococcal SAgs, it is necessary to have assays for them. At present there are 23 characterized, serologically distinct SAgs made by S. aureus: TSS toxin-1(TSST-1); staphylococcal enterotoxins (SEs) A, B (multiple variant forms exist), C (multiple minor variant forms exist), D, E, and G; and SE-like H, I, J, K, L, M, N, O, P, Q, R, S, T, U, V, and X. The most straightforward way to analyze S. aureus strains for SAgs is through polymerase chain reaction for their genes; we provide here our method for this analysis. Although it would be ideal to confirm that all of the same SAgs are produced by S. aureus strains that have the genes, antibody reagents for SAg detection are only available for TSST-1; SEs A-E and G; and enterotoxin-like proteins H, I, Q, and X. We provide a Western immunoblot procedure that allows in vitro quantification of these SAgs.

[Staphylococcus aureus broncho-pulmonary infections]

Staphylococcus aureus accounts for 2-5% of the etiologies of community-acquired pneumonia. These infections occur mainly in elderly patients with comorbidity, after a respiratory viral infection. S. aureus could also be responsible for necrotizing pneumonia, which occurs in young subjects, also after flu. Necrotizing pneumonia are associated with the production of a particular staphylococcal toxin called Panton-Valentine leukocidin, responsible for pulmonary focal necrosis, occurrence haemoptysis, leucopenia, and death. In Europe, these strains are still predominantly sensitive to anti-staphylococcal penicillin, which must be used at high dosage intravenously in combination with an antibiotic that reduces toxin production such as clindamycin, and intravenous immunoglobulin in severe cases. The mortality rate is estimated at 50%. In addition, S. aureus is one of the pathogens involved in early respiratory infections in cystic fibrosis patients, in whom methicillin resistance plays an important prognostic role. However, the involvement of S. aureus in COPD exacerbations is rare. Finally, S. aureus represents 20 to 30% of cases of hospital-acquired pneumonia, including ventilator-associated pneumonia. In these cases, methicillin-resistance is common and requires the use of glycopeptides or linezolid. The place of new anti-staphylococcal antibiotics such as new generation cephalosporins or tigecyclin remains to be defined.

Assessment of the interplay between blood and skin vascular abnormalities in adult purpura fulminans

RATIONALE

Purpura fulminans in adults is a rare but devastating disease. Its pathophysiology is not well known.

OBJECTIVES

To understand the pathophysiology of skin lesions in purpura fulminans, the interplay between circulating blood and vascular alterations was assessed.

METHODS

Prospective multicenter study in four intensive care units. Patients with severe sepsis without skin lesions were recruited as control subjects.

MEASUREMENTS AND MAIN RESULTS

Twenty patients with severe sepsis and purpura fulminans were recruited for blood sampling, and skin biopsy was performed in deceased patients. High severity of disease and mortality rates (80%) was observed. Skin biopsies in purpura fulminans lesions revealed thrombosis and extensive vascular damage: vascular congestion and dilation, endothelial necrosis, alteration of markers of endothelial integrity (CD31) and of the protein C pathway receptors (endothelial protein C receptor, thrombomodulin). Elevated plasminogen activating inhibitor-1 mRNA was also observed. Comparison with control patients showed that these lesions were specific to purpura fulminans. By contrast, no difference was observed for blood hemostasis parameters, including soluble thrombomodulin, activated protein C, and disseminated intravascular coagulation markers. Bacterial presence at the vascular wall was observed specifically in areas of vascular damage in eight of nine patients tested (including patients with Streptococcus pneumoniae, Neisseria meningitidis, Escherichia coli, and Pseudomonas aeruginosa infection).

CONCLUSIONS

Thrombi and extensive vascular damage with multifaceted prothrombotic local imbalance are characteristics of purpura fulminans. A "vascular wall infection" hypothesis, responsible for endothelial damage and subsequent skin lesions, can be put forward.

Comparison of methicillin-resistant and methicillin-sensitive Staphylococcus aureus strains isolated from a tertiary hospital in Terengganu, Malaysia

Staphylococcus aureus is a persistent human pathogen responsible for a variety of infections ranging from soft-tissue infections to bacteremia. The objective of this study was to determine genetic relatedness between methicillin-resistant S. aureus (MRSA) and methicillin-susceptible S. aureus (MSSA) strains. We isolated 35 MRSA and 21 MSSA strains from sporadic cases at the main tertiary hospital in Terengganu, Malaysia, screening them for the presence of virulence genes. Their genetic relatedness was determined by accessory gene regulator (agr) types, PCR-restriction fragment length polymorphism (RFLP) of the coa gene, pulsed-field gel electrophoresis (PFGE), S. aureus protein A (spa), and multilocus-sequence typing (MLST). We found that 57% of MRSA and 43% of MSSA strains harbored enterotoxin genes. The majority (87.5%) of the strains were agr type I. PCR-RFLP and PFGE genotyping of the coa gene revealed that MRSA strains were genetically related, whereas MSSA strains had higher heterogeneity. The combined genotype, MLST-spa type ST239-t037, was shared among MRSA and MSSA strains, indicating that MRSA strains could have evolved from MSSA strains. Two combined MLST-spa types were present in MRSA strains, whereas 7 different MLST-spa types were detected in MSSA strains, including 2 combined types (ST779-t878 and ST1179-t267) that have not been reported in Malaysia. In conclusion, enterotoxin genes were more prevalent in MRSA than in MSSA strains in the Terengganu hospital. The MSSA strains were genetically more diverse than the MRSA strains.

Neonatal purpura fulminans due to methicillin resistant Staphylococcus aureus

Neonatal purpura fulminans is rare and may be inherited or acquired. It may ultimately lead to multiorgan failure and death. Purpura fulminans in a premature neonate resulting from Staphylococcus aureus septicemia is illustrated. Unfortunately, the baby succumbed to septicemia.

Purpura fulminans in a patient with mixed connective tissue disease

A 43-year-old lady was admitted to the intensive care unit with sepsis. She had a history of mixed connective tissue disease, Raynaud's syndrome and hypothyroidism. 2 days later, she developed a purpuric rash on her face and extremities with a livedoid background. Few days later, her distal fingers and toes became gangrenous which then had to be amputated. Laboratory investigations showed that she was coagulopathic and had multiple organ dysfunctions. Antiphospholipid antibodies were negative; however, protein C and antithrombin III levels were low. A skin biopsy showed fibrinoid necrosis in the vessel wall with microthrombi and red-cell extravasation. A diagnosis of purpura fulminans was made.

A case of fulminant varicella infection with purpura fulminans, hepatitis, and rhabdomyolysis

Varicella zoster virus causes varicella which is a common disease. Generally it is self-limiting, and treatment is often unnecessary, but severe or life-threatening complications are rarely seen. We report a case of fulminant varicella complicating with purpura fulminans, hepatitis, and probable rhabdomyolysis in a previously healthy child.

COMMUNITY ACQUIRED METHICILLIN RESISTANT STAPHYLOCOCCUS AUREUS HAND INFECTIONS: A SOUTH PACIFIC PERSPECTIVE — CHARACTERISTICS AND IMPLICATIONS FOR ANTIBIOTIC COVERAGE

Purpose: Community acquired methicillin resistant Staphylococcus aureus (CA-MRSA) infections are reported to be increasing worldwide. In the United States when rates exceed 15% empiric treatment is suggested. The aim of our study was to determine local rates and treatment of CA-MRSA within our region.

Methods: Nine hundred and forty-two patients were admitted to our service during a six-year period with culture-positive hand infections identified from operative cultures at the time of surgery.

Results: Sixty-six (7.0%) patients had CA-MRSA positive cultures identified. Thirty-two (48.5%) patients were noted to have remained on antibiotic treatment that did not reflect their MRSA positive status after cultures returned. Despite this, re-admission and re-operation rates were low and comparable to our non-MRSA control group.

Conclusions: Within our CA-MRSA group, current rates do not support automatic empiric treatment for CA-MRSA. Based on sensitivity data, co-trimoxazole and intravenous vancomycin are appropriate and effective antibiotic treatment within our region. Our data supports the importance of drainage of pyogenic infections in helping to resolve complicated hand infections.

Characterisation of the Virulence Factors and Genetic Types of Methicillin Susceptible Staphylococcus aureus from Patients and Healthy Individuals

Methicillin sensitive Staphylococcus aureus is an important bacterial pathogen associated with hospital- and community-acquired infections leading to endocarditis, skin tissue infection and pneumonia. The objective of this study was to determine both the genetic characteristics of methicillin-sensitive S. aureus (MSSA) strains, and the occurrence of virulence factors produced by S. aureus strains isolated from UMMC and healthy students in the University from year 2009. Out of 429 nasal swab samples, 67 were MSSA. The prevalence of 21 different virulence genes among 67 Malaysian clinical and community MSSA strains was determined by PCR, and their genetic features were assessed by PCR-RFLP of coa gene, agr types, spa typing and PFGE. The five predominant virulence genes were ica (79 %), efb and fnbA (61 % each), sdrE (57 %) and hlg (45 %). Toxin genes (enterotoxin, etd and pvl) were significantly more common (P < 0.05) in clinical strains compared to community strains. Three agr genotypes were observed: agr type I (45 %), agr type III (25 %) and agr type II (19 %). All 67 MSSA strains were distinguished into 26 profiles by PCR-RFLP of coa, 55 pulsotypes and 21 spa types. Four novel spa types (t7312, t7581, t7582 and t7583) were observed. In conclusion, different virulence profiles were observed in MSSA strains in Malaysia where toxin genes were more prevalent among clinical strains. No correlation between DNA profiles (coa-RFLP, PFGE and spa) and virulotypes was observed. The Malaysian MSSA strains from clinical and community sources were genetically diverse and heterogeneous.

Chlorhexidine gluconate reduces transmission of methicillin-resistant Staphylococcus aureus USA300 among Marine recruits

BACKGROUND

Methicillin-resistant Staphylococcus aureus (MRSA) pulsed-field type (PFT) USA300 causes skin and soft tissue infections in military recruits and invasive disease in hospitals. Chlorhexidine gluconate (CHG) is used to reduce MRSA colonization and infection. The impact of CHG on the molecular epidemiology of MRSA is not known.

OBJECTIVE

To evaluate the impact of 2% CHG-impregnated cloths on the molecular epidemiology of MRSA colonization.

DESIGN

Cluster-randomized, double-blind, controlled trial.

SETTING

Marine Officer Candidate School, Quantico, Virginia, in 2007.

PARTICIPANTS

Military recruits.

INTERVENTION

Thrice-weekly application of CHG-impregnated or control (Comfort Bath; Sage) cloths over the entire body.

MEASUREMENTS

Baseline and serial (every 2 weeks) nasal and/or axillary swab samples were assessed for MRSA colonization. Molecular analysis was performed with pulsed-field gel electrophoresis.

RESULTS

During training, 77 subjects (4.9%) acquired MRSA, 26 (3.3%) in the CHG group and 51 (6.5%) in the control group (P=.004). When analyzed for PFT, 24 subjects (3.1%) in the control group but only 6 subjects (0.8%) in the CHG group (P=.001) had USA300. Of the 167 colonizing isolates recovered from 77 subjects, 99 were recovered from the control group, including USA300 (40.4%), USA800 (38.4%), USA1000 (12.1%), and USA100 (6.1%), and 68 were recovered from the CHG group, including USA800 (51.5%), USA100 (23.5%), and USA300 (13.2%).

CONCLUSIONS

CHG decreased the transmission of MRSA--more specifically, USA300--among military recruits. In addition, USA300 and USA800 outcompeted other MRSA PFTs at incident colonization. Future studies should evaluate the broad-based use of CHG to decrease transmission of USA300 in hospital settings.

Illness severity in community-onset invasive Staphylococcus aureus infection and the presence of virulence genes

BACKGROUND

It is uncertain whether particular clones causing invasive community-onset methicillin-resistant and methicillin-sensitive Staphylococcus aureus (cMRSA/cMSSA) infection differ in virulence.

METHODS

Invasive cMRSA and cMSSA cases were prospectively identified. Principal component analysis was used to derive an illness severity score (ISS) from clinical data, including 30-day mortality, requirement for intensive hospital support, the presence of bloodstream infection, and hospital length of stay. The mean ISS for each S. aureus clone (based on MLST) was compared with its DNA microarray-based genotype.

RESULTS

Fifty-seven cMRSA and 50 cMSSA infections were analyzed. Ten clones caused 82 (77%) of these infections and had an ISS calculated. The enterotoxin gene cluster (egc) and the collagen adhesin (cna) gene were found in 4 of the 5 highest-ranked clones (ST47-MSSA, ST30-MRSA-IV[2B], ST45-MSSA, and ST22-MRSA-IV[2B]) compared with none and 1 of the lowest 5 ranked clones, respectively. cMSSA clones caused more severe infection than cMRSA clones. The lukF/lukS Panton-Valentine leukocidin (PVL) genes did not directly correlate with the ISS, being present in the second, fourth, and 10th most virulent clones.

CONCLUSIONS

The clinical severity of invasive cMRSA and cMSSA infection is likely to be attributable to the isolates' entire genotype rather than a single putative virulence determinant such as PVL.

Comparison of Staphylococcus aureus strains for ability to cause infective endocarditis and lethal sepsis in rabbits

Staphylococcus aureus is a major cause of infective endocarditis (IE) and sepsis. Both methicillin-resistant (MRSA) and methicillin-sensitive (MSSA) strains cause these illnesses. Common S. aureus strains include pulsed-field gel electrophoresis (PFGE) types USA200, 300, and 400 types where we hypothesize that secreted virulence factors contribute to both IE and sepsis. Rabbit cardiac physiology is considered similar to humans, and rabbits exhibit susceptibility to S. aureus superantigens (SAgs) and cytolysins. As such, rabbits are an excellent model for studying IE and sepsis, which over the course of four days develop IE vegetations and/or fatal septicemia. We examined the ability of MRSA and MSSA strains (4 USA200, 2 USA300, 2 USA400, and three additional common strains, FRI1169, Newman, and COL) to cause vegetations and lethal sepsis in rabbits. USA200, TSST-1⁺ strains that produce only low amounts of α-toxin, exhibited modest LD₅₀ in sepsis (1 × 10⁸ – 5 × 10⁸) colony-forming units (CFUs), and 3/4 caused significant IE. USA200 strain MNPE, which produces high-levels of α-toxin, was both highly lethal (LD₅₀ 5 × 10⁶ CFUs) and effective in causing IE. In contrast, USA300 strains were highly effective in causing lethal sepsis (LD₅₀s 1 × 10⁶ and 5 × 10⁷ CFUs) but were minimally capable of causing IE. Strain Newman, which is phylogenetically related to USA300 strains, was not highly lethal (LD₅₀ of 2 × 10⁹ CFUs) and was effective in causing IE. USA400 strains were both highly lethal (LD₅₀s of 1 × 10⁷ and 5 × 10⁷ CFUs) and highly effective causes of IE. The menstrual TSS isolate FRI1169, that is TSST-1⁺, produces high-levels of α-toxin, but is not USA200, was both highly lethal and effective in causing IE. Additional studies showed that phenol soluble modulins (PSMs) produced by FRI1169 were important for sepsis but did not contribute to IE. Our studies show that these clonal groups of S. aureus differ in abilities to cause IE and lethal sepsis and suggest that secreted virulence factors, including SAgs and cytolysins, account for some of these differences.

Progress toward a Staphylococcus aureus vaccine

High attack rates and the ability of Staphylococcus aureus to develop resistance to all antibiotics in medical practice heightens the urgency for vaccine development. S. aureus causes many disease syndromes, including invasive disease, pneumonia, and skin and soft tissue infections. It remains unclear whether a single vaccine could protect against all of these. Vaccine composition is also challenging. Active immunization with conjugated types 5 and 8 capsular polysaccharides, an iron scavenging protein, isdB, and passive immunization against clumping factor A and lipoteichoic acid have all proven unsuccessful in clinical trials. Many experts advocate an approach using multiple antigens and have suggested that the right combination of antigens has not yet been identified. Others advocate that a successful vaccine will require antigens that work by multiple immunologic mechanisms. Targeting staphylococcal protein A and stimulating the T-helper 17 lymphocyte pathway have each received recent attention as alternative approaches to vaccination in addition to the more traditional identification of opsonophagocytic antibodies. Many questions remain as to how to successfully formulate a successful vaccine and to whom it should be deployed.