ABSTRACT
Impetigo is a common cutaneous infection that is especially prevalent in children. Historically, impetigo is caused by either group A β-hemolytic streptococci or Staphylococcus aureus. Currently, the most frequently isolated pathogen is S. aureus. This article discusses the microbiologic and virulence factors of group A β-hemolytic streptococci and Staphylococcus aureus, clinical characteristics, complications, as well as the approach to diagnosis and management of impetigo. Topical agents for impetigo therapy are reviewed.
Subject(s)
Humans , Impetigo/pathology , Impetigo/drug therapy , Anti-Bacterial Agents/therapeutic use , Staphylococcus/pathogenicity , Streptococcus/pathogenicity , Administration, Topical , Drug Resistance, Bacterial , Impetigo/microbiologyABSTRACT
Simplified methods of DNA extraction for amplification and sequencing for emm typing of group A streptococci (GAS) can save valuable time and cost in resource crunch situations. To evaluate this, we compared two methods of DNA extraction directly from colonies with the standard CDC cell lysate method for emm typing of 50 GAS strains isolated from children with pharyngitis and impetigo. For this, GAS colonies were transferred into two sets of PCR tubes. One set was preheated at 94 degrees C for two minutes in the thermal cycler and cooled while the other set was frozen overnight at -20 degrees C and then thawed before adding the PCR mix. For the cell lysate method, cells were treated with mutanolysin and hyaluronidase before heating at 100 degrees C for 10 minutes and cooling immediately as recommended in the CDC method. All 50 strains could be typed by sequencing the hyper variable region of the emm gene after amplification. The quality of sequences and the emm types identified were also identical. Our study shows that the two simplified DNA extraction methods directly from colonies can conveniently be used for typing a large number of GAS strains easily in relatively short time.
Subject(s)
Antigens, Bacterial/genetics , Bacterial Outer Membrane Proteins/genetics , Bacterial Proteins/genetics , Bacterial Typing Techniques/methods , Child , Child, Preschool , DNA, Bacterial/analysis , Freezing , Hot Temperature , Humans , Impetigo/microbiology , Pharyngitis/microbiology , Polymerase Chain Reaction/methods , Sequence Analysis, DNA , Streptococcal Infections/microbiology , Streptococcus pyogenes/classificationABSTRACT
Son presentados 100 niños con diagnóstico clínico de Impétigo de los cuales 70 fueron estudiados bacteriologicamente. La signo-sintomatología es la habitualmente descripta en este tipo de afección y el principal germen involucrado fue el Estreptococo que predominó más a menor edad del paciente, fue más afectado el sexo masculino y no se detectaron durante el estudio complicaciones atribuibles a esta patología, ya sea por extensión o la debida a fenómenos con participación inmunológica
Subject(s)
Infant, Newborn , Infant , Child, Preschool , Child , Adolescent , Humans , Male , Female , Impetigo/microbiology , Streptococcal Infections , Streptococcus , Age Factors , Sex Factors , Staphylococcal Infections , Staphylococcus , Staphylococcus aureusABSTRACT
Eight hundred and sixty four children were admitted with Acute post-streptococcal glomerulonephritis (APSGN) at the Institute for Child Health, Madras, during the period January 1981 to January 1983. Majority of the cases followed infected scabies or impetigo. 135 children were investigated and followed up for a period of 1-2 years. The disease had an excellent prognosis in these children. None of those examined 2 years after discharge had proteinuria or hypertension. Group A beta hemolytic streptococcus (BHS) was isolated in 13.4% of patients and 11.25% of skin infection controls. Eight different T types were identified in patients and 6 T types in pyoderma cases. All patients and 87% of skin infection controls had elevated anti-D Nase B titres, while ASO titres were not significantly raised.