Características clínicas y microbiológicas de infecciones de piel y partes blandas en pacientes pediátricos de dos hospitales de Buenos Aires / Skin and soft tissue infections in pediatrics

Las infecciones de piel y partes blandas (IPPB) en niños son una de las principales causas de prescripción de antimicrobianos. El objetivo del estudio fue describir las características clínicas y microbiológicas de las IPPB ambulatorias de niños asistidos en dos hospitales zonales. Se realizó un estudio prospectivo entre el 1/11/2017 y el 1/11/2018. Se incluyeron pacientes entre 1 mes y 15 años internados en dos hospitales. Se evaluó: edad, sexo, localidad, factores predisponentes, tipo de IPPB, muestras biológicas realizadas, aislamiento microbiológico, tratamiento empírico indicado y evolución del cuadro. Se realizó antibiograma y determinación genética. Se calculó chi2, IC95, OR; α=5%. N= 94. 58,7% masculinos. 12 pacientes <1 año, 85 >1 año (promedio de edad 4 años, 1-15). El 36% de Tandil y 63,8% de Florencio Varela. El 59,6% corresponden a IPPB purulentas. Se aislaron microorganismos en un 59,6%. Los aislamientos principales: SAMR (40,4%), SAMS (7,4%), S. agalactiae (2,1%) y S. pyogenes (2,1%). El 100% de SAMR son portadores de gen mecA y SCCmec tipo IV, sin multirresistencia. No hubo diferencia estadística entre los factores de riesgo evaluados para el desarrollo de IPPB por SAMR. El 52,1% de los niños recibió tratamiento antibiótico combinado, siendo la más indicada TMS-SMX + CLI en 36 eventos. (38,3%). La evolución fue favorable: no hubo diferencia significativa entre el subgrupo que se aisló SAMR y el que no se aisló SAMR; 91,9% (34/37) y 92,6% (50/54) correspondientemente (chi2: 0,01; p= 0,97 IC95: 0,26-3,88). El principal agente etiológico fue SAMRco, debiendo adecuar los tratamientos a este microorganismo.

Skin and soft tissue infections (SSIs) in children are one of the main causes of antimicrobial prescription. The aim of the study was to describe the clinical and microbiological characteristics of outpatient SSIs in children attended in two hospitals. A prospective study was conducted between 11/1/2017 and 11/1/2018. Patients between 1 month and 15 years old, hospitalized were included. We evaluated: age, sex, locality, predisposing factors, type of IPPB, biological samples taken, microbiological isolation, empirical treatment indicated and evolution of the condition. An antibiogram and genetic determination were performed. Chi2, CI95, OR; α=5% were calculated. N= 94. 58.7% male. 12 patients <1 year, 85 >1 year (mean age 4 years, 1-15). 36% were from Tandil and 63.8% from Florencio Varela. 59.6% corresponded to purulent SSIs. The diagnostic yield was 59.6%. Main isolates: MRSA (40.4%), MSSA (7.4%), S. agalactiae (2.1%) and S. pyogenes (2.1%). 100% of MRSA carried the mecA gene and SCCmec type IV, with no multidrug resistance. There was no statistical difference between the risk factors evaluated. 52.1% of children received combined antibiotic treatment, the most indicated being TMS-SMX + CLI in 36 events. (38,3%). Evolution was favorable: there was no significant difference between the subgroup that isolated MRSA and the subgroup that did not isolate MRSA; 91.9% (34/37) and 92.6% (50/54) respectively (chi2: 0.01; p= 0.97 CI95: 0.26-3.88). The main etiological agent was MRSA, and treatments should be adapted to this microorganism

Enfrentamiento de las infecciones de piel en el adulto / Managing adult skin infections

En la actualidad, las infecciones de piel y partes blandas forman parte de un alto porcentaje de las consultas en salud. Estas van desde infecciones leves, donde el manejo se realiza con tratamiento tópico, hasta aquellas con severo compromiso sistémico, requiriendo terapia antibiótica sistémica e incluso el desbridaje quirúrgico. En general, son producto de un desbalance entre los mecanismos de defensa de la barrera cutánea y los factores de virulencia y patogenicidad de los microorganismos que la afectan. Se pueden clasificar según distintos criterios, como por ejemplo, profundidad, gravedad, microorganismos involucrados y si estas son purulentas o no. El reconocer estas entidades clínicas es de suma importancia para llevar a cabo un adecuado tratamiento en los pacientes que presentan estas afecciones, ya que los diagnósticos erróneos llevan a las múltiples consultas con el consiguiente aumento de costos asociados en atención en salud.

Currently, skin and soft tissue infections are part of a high percentage of health consultations. These range from mild infections, where management is performed with topical treatment, to those with severe systemic compromise requiring systemic antibiotic therapy and even surgical debridement. In general, they are the product of an imbalance between the defense mechanisms of the skin barrier and the virulence and pathogenicity factors of the microorganisms that affect it, which can vary from bacterial, viral, fungal and parasites agents. Skin and soft tissue infections can be classified according to different criteria, such as depth, severity, microorganisms involved and whether they are purulent or not. Recognizing these clinical entities is of utmost importance to carry out adequate treatment in patients with these conditions, since erroneous diagnoses lead to multiple consultations with the consequent increase in costs associated with health care

High frequency of methicillin-susceptible and methicillin-resistant Staphylococcus aureus in children under 1 year old with skin and soft tissue infections / Alta frequência de S. aureus (MSSA-MRSA) em crianças com menos de um ano deidade com infecções de pele e do tecido mole

Abstract Objective: Staphylococcus aureus is responsible for a large number of infections in pediatric population; however, information about the behavior of such infections in this population is limited. The aim of the study was to describe the clinical, epidemiological, and molecular characteristics of infections caused by methicillin-susceptible and resistant S. aureus (MSSA-MRSA) in a pediatric population. Method: A cross-sectional descriptive study in patients from birth to 14 years of age from three high-complexity institutions was conducted (2008-2010). All patients infected with methicillin-resistant S. aureus and a representative sample of patients infected with methicillin-susceptible S. aureus were included. Clinical and epidemiological information was obtained from medical records and molecular characterization included spa typing, pulsed-field gel electrophoresis (PFGE), and multilocus sequence typing (MLST). In addition, staphylococcal cassette chromosome mec (SCCmec) and virulence factor genes were detected. Results: A total of 182 patients, 65 with methicillin-susceptible S. aureus infections and 117 with methicillin-resistant S. aureus infections, were included in the study; 41.4% of the patients being under 1 year. The most frequent infections were of the skin and soft tissues. Backgrounds such as having stayed in day care centers and previous use of antibiotics were more common in patients with methicillin-resistant S. aureus infections (p ≤ 0.05). Sixteen clonal complexes were identified and methicillin-susceptible S. aureus strains were more diverse. The most common cassette was staphylococcal cassette chromosomemec IVc (70.8%), which was linked to Panton-Valentine leukocidin (pvl). Conclusions: In contrast with other locations, a prevalence of infections in children under 1 year of age in the city could be observed; this emphasizes the importance of epidemiological knowledge at the local level.

Resumo Objetivo: O Staphylococcus aureus é responsável por um grande número de infecções na população pediátrica; contudo, as informações sobre o comportamento dessas infecções nessa população são limitadas. O objetivo do estudo foi descrever as características clínicas, epidemiológicas e moleculares de infecções causadas por Staphylococcus aureus suscetíveis e resistentes à meticilina (MSSA-MSRA) em uma população pediátrica. Método: Um estudo transversal descritivo foi realizado em pacientes entre 0 e 14 anos de idade de três instituições de alta complexidade (2008-2010). Todos os pacientes infectados com S. aureus resistentes à meticilina e uma amostra representativa de pacientes infectados com S. aureus suscetíveis à meticilina foram incluídos. As informações clínicas e epidemiológicas foram obtidas de prontuários médicos, e a caracterização molecular incluiu tipagem spa, Eletroforese em Gel de Campo Pulsado (PFGE) e Tipagem de sequências multilocus (MLST). Além disso, o Cassete Cromossômico Estafilocócico mec (SCCmec) e genes de fatores de virulência foram detectados. Resultados: 182 pacientes, 65 com infecções por S. aureus suscetíveis à meticilina e 117 com infecções por S. aureus resistentes à meticilina, foram incluídos no estudo; 41,4% dos pacientes com menos de um ano de idade. As infecções mais frequentes foram da pele e dos tecidos moles. Os históricos como internações em centros de atendimento e o uso prévio de antibióticos foram mais comuns em pacientes com infecções por S. aureus resistentes à meticilina (p ≤ 0,05). Dezesseis complexos clonais foram identificados, e as cepas de S. aureus suscetíveis à meticilina foram mais diversificadas. O cassete mais comum foi o Cassete Cromossômico Estafilocócicomec IVc (70,8%), relacionado à leucocidina de panton-valentine (pvl). Conclusões: Em comparação a outros locais, observamos uma prevalência de infecções em crianças com menos de um ano de idade na cidade; o que enfatiza a importância de conhecer a epidemiologia em nível local.

Management of urinary tract infections, decubitus ulcer and pneumonia in the aging person

Infections in the older person are common and a significant cause of morbidity and mortality. Infections of the urinary tract, skin and soft tissue infections including decubitus ulcers, antibiotics associated diarrhea and lower respiratory tract infections are particularly important in the elderly because of their frequency. While most initial antibiotic therapy is empiric, its important before treatment to try to document the etiology for better use of antibiotics. Infections of the urinary tract are frequently and potentially serious in the elderly, they must be separated from asymptomatic bacteriuria that requires no therapy. Upper and lower urinary tract infections are frequently caused by aerobic gram negative bacilli and or enterococci. Most authors prefer the use of fluoroquinolones to manage such infections. The elderly with decubitus ulcer presents a problem in management, since these are frequent polymicrobic infections in which anaerobes play an important role. The initial therapy usually involves the combination of a fluoroquinolone plus an antianaerobic agent like clindamycin. C. difficile diarrhea as frequent in nursing home residents as well as the older person with prior antibiotics. The treatment should be with metronidazole and avoid the use of vancomycin. Pneumonias in the elderly can be acquired in the community, the nursing home or during a hospitalization. The etiologic agents that predominate change from S. pneumoniae and atypicals in those from the community to an increase in gram negative pneumonia. The initial treatment as started by most authors as well as guidelines include the use of a new fluoroquinolone like gatifloxacin alone or in combination with a beta-lactamic agent like ceftriaxone. For those infections acquired in the hospital therapy with third or fourth generation cephalosporins, carbapenems, beta-lactams with betalactamase inhibitors alone or in combination with an aminoglucoside and or vancomycin if MRSA is suspected is accepted therapy

Oedematous skin disease: a recurring infection in buffaloes

Eighteen Corynebacterium pseudotuberculosis were isolated from 30 specimens [9 biopsies from closed skin lesions and 21 exudate specimens from open lesions] collected from 27 buffalos with symptoms of skin infection. C. pseudotuberculosis was isolated in pure cultures from 6 out of 9 biopsies and in mixed cultures from 12 out of 21 exudate specimens. The majority of isolates were of biotype II [15 isolates], whereas only 3 isolates were of biotype I. The pattern of isolation of both biotypes I and II from biopsies and exudate specimens was similar. Both biotypes I and II differed in their course of pathogenicity in G. pigs. C. pseudotuberculosis was not isolated from blood suckling and biting flies [236 files] existed on the infected animals and in their premises. This might rule out the role of vectors in transmission of infection. In-vitro antibiotic sensitivity testing revealed that C. pseudotuberculosis isolates were most sensitive to penicillin 89%, amoxycillin 89%, erythromycin 83%, chloramphenicol 78% and ampicillin 78%. The histological examination of skin biopsies from the diseased buffalos showed inflammatory reaction due to the bacterial infection

Virulence factors in Bacteroides fragilis group.

Attempts were made to study the virulence factors in some strains of B. fragilis group in the rat model. Subcutaneous wound abscesses could be produced by 10(9) CFU/ml of live cells of all the five species of B. fragilis group tested. For determination of virulence factor cellular components (capsular polysaccharide and lipopolysaccharide) of B. fragilis were separated using gel filtration technique and injected in rats. Abscesses could be produced only by capsular polysaccharide fraction suggesting it to be the virulence factor. Studies with transmission electron microscope showed presence of capsular polysaccharide in B. fragilis and B. thetaiotaomicron, it was doubtful in B. distasonis and absent in B. ovatus and B. vulgatus. This suggested that virulence factors other than capsular polysaccharide may be responsible for pyogenic lesions in the noncapsulated species of B. fragilis group. The abscess could not be produced by 10(9) CFU/ml of heat killed cells of non-capsulated B. ovatus and B. vulgatus indicating that in live bacteria, a heat labile factor was responsible for the development of abscess.

Scanning electron microscopy of Malassezia furfur in tinea versicolor

Morphologic features of Malassezia(M.) furfur in the horny layer from clinical lesions of tinea versicolor were examined by scanning electron microscopy and compared with the appearance of fungus in the horny layer from normal skin and in culture. In skin lesions of tinea versicolor, M. furfur showed a variety of growth and reproduction patterns. Although the main patterns were budding yeast forms, various patterns suggesting yeast-mycelial conversion were observed and mycelial hyphae were more prominent in the deeper horny layer than in the superficial layers. However, in the skin of normal persons and in culture, M. furfur existed only as yeast forms and no mycelial hyphae or yeast-mycelial conversion forms were seen. This suggests that the morphologic change of M. furfur, from a yeast form to a mycelial hypha one, may play a role in the induction of the clinical lesion of tinea versicolor.

Scanning electron microscopy of Malassezia furfur in tinea versicolor

Morphologic features of Malassezia(M.) furfur in the horny layer from clinical lesions of tinea versicolor were examined by scanning electron microscopy and compared with the appearance of fungus in the horny layer from normal skin and in culture. In skin lesions of tinea versicolor, M. furfur showed a variety of growth and reproduction patterns. Although the main patterns were budding yeast forms, various patterns suggesting yeast-mycelial conversion were observed and mycelial hyphae were more prominent in the deeper horny layer than in the superficial layers. However, in the skin of normal persons and in culture, M. furfur existed only as yeast forms and no mycelial hyphae or yeast-mycelial conversion forms were seen. This suggests that the morphologic change of M. furfur, from a yeast form to a mycelial hypha one, may play a role in the induction of the clinical lesion of tinea versicolor.

Mucormicosis: infeccion necrosante de tejidos blandos por Rhizopus arrhizus / Mucormycosis: necrotizing infection of soft tissues by Rhizopus arrhizus

Se informa un nuevo caso de mucormicosis cutanea por Rhizopus arrhizus, observado en una paciente lesionada durante la catastrofe acaecida en Armero, Colombia, en noviembre de 1985. Se revisa la literatura y se plantea una nueva forma de clasificacion de las infecciones necrosantes de la piel y tejidos blandos, dividiendolas en clostridiales, no clostridiales y micoticas para facilitar su diagnostico y tratamiento.