ABSTRACT
Staphylococcus aureus is an important pathogen of human infectious diseases, which can cause skin and soft tissue infections, endocarditis, necrotizing pneumonia, myelitis and other serious infectious diseases. With the use of antibiotics, Staphylococcus aureus is evolving to develop drug resistance; at the same time it produces a variety of virulence factors to attack the host. This article will review the recent advances of Staphylococcus aureus virulence factors associated with the three stages of infection and introduce the detection methods of virulence factors briefly.
ABSTRACT
The emergence of methicillin-resistant Staphylococcus aureus (MRSA) strains possessing virulence genes encoding such toxins as exfoliative toxins (ETs), toxic shock syndrome toxin-1 (TSST-1), is worrying, especially in relation to the increasing frequency of nosocomial infections. The present study aimed to determine the prevalence of genes encoding ETs and TSST-1 in MRSA isolates by polymerase chain reaction (PCR). The results showed that out of 88 investigated MRSA isolates, tst and etb toxin gene were found in 3 (3.4%) and 2 (2.3%) respectively, while none eta toxin genes were detected. It was concluded that the incidence of ET and TSST-1encoding genes among MRSA isolates in Makkah is lower or near to the global prevalence.
ABSTRACT
Staphylococcal scalded skin syndrome (SSSS) is an acute dermatological illness which requires prompt treatment. It is a condition associated with widespread exfoliation of skin caused by Staphylococcus aureus (SA). The toxins elaborated by these gram positive microorganisms especially the exfoliative toxins A and B causes the SSSS. Literature review mentions that only 5% of SA produces these exfoliative toxins. The main route of spread of the toxins is by the hematogenous spread and the process results in extensive damage to the epidermis. This case series reports the SSSS in two children and highlights the significance of promptly diagnosing this serious pediatric dermatological illness.
ABSTRACT
El síndrome estafilocócico de la piel escaldada (SEPE) es una enfermedad cutánea aguda infrecuente, causada por toxinas exfoliativas del Staphylococcus aureus. El objetivo de este estudio es describir las características epidemiológicas, clínicas y terapéuticas de los pacientes con diagnóstico de SEPE en nuestro medio.Material y métodos.Se realizó un estudio retrospectivo, descriptivo y observacional, en el que se revisaron las historias clínicas de los pacientes con diagnóstico de SEPE vistos entre mayo de 2000 y mayo de 2010, atendidos en la Sección de Dermatología Pediátrica del Hospital Ramos Mejía, y entre mayo de 2005 y mayo de 2010 en el Servicio de Dermatología del Hospital Alemán.Resultados.Se incluyó un total de 62 pacientes, cuya edad media al momento del diagnóstico fue de 22 meses. No se observó predilección por sexo ni estación del año. El 13% de los pacientes recibió corticoides sistémicos previo al diagnóstico de SEPE. Todos los pacientes excepto uno, realizaron tratamiento antibiótico luego del diagnóstico de esta entidad. El 92% recibió cefalosporinas de primera generación. El 23% de los pacientes requirió internación y el 100% evolucionó satisfactoriamente.Conclusiones.El SEPE es una entidad poco frecuente. Si bien en nuestro medio no hallamos datos epidemiológicos sobre esta entidad, los datos demográficos encontrados en este estudio difieren de los publicados en la literatura mundial. Debe sospecharse en recién nacidos y niños pequeños con eritrodermia aguda y afectación peribucal o conjuntival.
Staphylococcal scalded skin syndrome (SSSS) is a rare cutaneous disease caused by exfoliativetoxins of Staphylococcus aureus. The aim of this study is to describe the epidemiology, clinicalmanifestations and treatment of patients with the diagnosis of SSSS in our community.Methods. We conducted a retrospective, descriptive and observational study, reviewing the clinicalrecords of patients with a diagnosis of SSSS, as seen between May 2000 and May 2010 atthe Pediatric Dermatology Section of the Hospital Ramos Mejía, and between May 2005 and May2010 at the Dermatology Unit of the Hospital Alemán.Results. A total of 62 patients were included, whose average age at the time of diagnosis was22 months. No predilection for sex or season of the year was observed. Thirteen percent of thepatients received systemic steroids prior to SSSS diagnosis. All but one of the patients received antibiotictreatment after the diagnosis of this entity. First generation cephaloporins were given to92% of patients; 23% of them required hospitalization and all of them had a satisfactory outcome.Discussion. SSSS is an infrequent entity. Even though there are no epidemiological studies inour country concerning SSSS, the data we gathered differs with world-wide published literature.SSSS must be suspected in new-borns and in young children with an acute onset of erythroderma,perioral affectation and conjunctivitis.
Subject(s)
Male , Infant, Newborn , Infant , Child , Female , Staphylococcal Infections/diagnosis , Staphylococcal Infections/epidemiology , Staphylococcal Infections/microbiology , Staphylococcal Scalded Skin Syndrome/epidemiology , Anti-Bacterial Agents/pharmacology , Exfoliatins , Skin/microbiology , Skin/pathology , Staphylococcus aureusABSTRACT
In the present study, Staphylococcus (S.) hyicus strains isolated in Russia (n = 23) and Germany (n = 17) were investigated for the prevalence of the previously described genes sheta and shetb. Sheta was detected in 16 S. hyicus strains. Sheta-positive strains were mainly found among strains isolated from exudative epidermitis, and frequently together with the exfoliative toxin-encoding genes exhD and exhC. Partial sequencing of sheta in a single S. hyicus strain revealed an almost complete match with the sheta sequence obtained from GenBank. None of the S. hyicus strains displayed a positive reaction with the shetb-specific oligonucleotide primer used in the present study. According to the present results, the exotoxin encoding gene sheta seems to be distributed among S. hyicus strains in Russia and Germany. The toxigenic potential of this exotoxin, which does not have the classical structure of a staphylococcal exfoliative toxin, remains to be elucidated.
Subject(s)
Animals , Cattle , Dogs , Cattle Diseases/epidemiology , DNA Primers , Dog Diseases/epidemiology , Epidermitis, Exudative, of Swine/epidemiology , Exfoliatins/genetics , Germany , Pneumonia/epidemiology , Russia , Staphylococcal Infections/immunology , Staphylococcus aureus/genetics , Swine , Swine Diseases/epidemiology , Virulence/genetics , Virulence Factors/geneticsABSTRACT
Objective To study the action and mechanism of staphylococcal exfoliative toxin A(E-TA)on pemphigus foliaceus antigen(PFA)and pemphigus vulgaris antigen(PVA)expressed on cultured human keratinocytes.Methods Stratified human keratinocytes were incubated with ETA and then stained with sera from patients with pemphigus foliaceus or pemphigus vulgaris as the first antibodies and FITC-la-beled sheep anti-human IgG as the second antibody.Total protein was harvested from the cells pretreated with ETA and run on SDS-PAGE for Western blot with the same antibodies.Simultaneously,supernatants of the keratinocytes before and after ETA treatment were collected for detection of the levels of IL-1?,IL-6with ELISA kits.The caseinolytic activities of the supernatants were tested by spectrometry in which casein was used as a non-specific substrate.Results Down-expression of PFA was shown after ETA treatment while no change of PVA expression was found.The high intensity and continuous linear appearance of fluo-rescent staining before ETA treatment became weak and discontinuous after ETA treatment,which were re-covered gradually in24hours.The degradation of proteins recognized by PF sera after ETV treatment was revealed by Western blot.The decreasing tendency of IL-1?concentration was found in the supernatants of cell culture after ETA treatment,but IL-6level was too low to be detected.Increased caseinolytic activities were found in the supernatants,and declined36hours after ETA treatment.Conclusions ETA acts on PFA expressed on keratinocytes in vitro,which is reversible along with withdrawal of ETA.The mechanism of E-TA act on PFA may be related to proteolytic action instead of promoting cytokine secretion.