ABSTRACT
Con la introducción de vacunas conjugadas antineumocócicas se observó, en muchos países, disminución de aislamientos de Streptococcus pneumoniae del serotipo 14 y aumento de aislamientos correspondientes a serotipos no incluidos en esas vacunas. En 1993, el Hospital de Niños de Santa Fe comenzó la vigilancia de la distribución de serotipos de Streptococcus pneumoniae invasores. En este trabajo se estudió la correlación entre serotipo y a) patología (neumonía/meningitis), b) edad (menor o mayor de dos años), y c) CIM de penicilina, para los serotipos aislados en el período 2003-2005. El serotipo predominante fue el 14, seguido del 1, 6B, 18C, 7F, 19F y 5. El serotipo 14 mostró asociación estadísticamente significativa con valores de CIM de penicilina entre 0,5 y 2 mg/l, no así con alguna patología, aunque se lo halló con mayor frecuencia en neumonías que en meningitis. Los serotipos 14 y 1 prevalecieron en niños menores y mayores de 2 años, respectivamente. La CIM de penicilina = 2 mg/l se observó más en neumonías que en meningitis. La frecuencia relativa de los diferentes serotipos hallados fue semejante a la observada en el período 1993-99; no obstante, los serotipos 18C, 4, 12F y 22F no se habían encontrado antes. La aparición de nuevos serotipos convierte en importante la vigilancia, dada la necesidad de formular vacunas que los incluyan y que efectivamente prevengan las infecciones neumocócicas más comunes.
The serotype distribution of Streptococcus pneumoniae varies through time. The introduction of pneumococcal conjugate vaccines showed a decreased prevalence of pneumococcal invasive isolates belonging to serotype 14 and an increase of serotypes not therein included. In 1993, the Hospital de Niños of Santa Fe began surveillance of the serotype distribution of invasive S. pneumoniae disease. In the period 2003 - 2005, 76 isolates were analysed by studying the correlation between serotype and pathology, age and MIC of penicillin. Serotype 14 was the most frequent followed by serotypes 1, 6B, 18C, 7F, 19 F and 5. Serotype 14 showed a statistically significant correlation with MICs of penicillin ranging from 0,5 to 2 mg/l. Although this serotype was more frequently observed in pneumonia than in meningitis, there was not a significant association with any particular pathology. Serotypes 14 and 1, were prevalent among children under and over 2 years old, respectively. Most of these isolates with MICs of penicillin = 2 mg/l, were from patients with pneumonia and not with meningitis. The serotype distribution was similar to that during the period 1993-99, with the exception of serotypes 18C, 4, 12F and 22F which had never been found before. The emergence of these serotypes makes it essential to continue surveillance to determine which conjugated vaccine formulation would be suitable to prevent the most frequent pneumococcal invasive infections.
Subject(s)
Child , Humans , Meningitis, Bacterial/microbiology , Pneumonia, Bacterial/microbiology , Streptococcus pneumoniae/classification , Streptococcus pneumoniae/isolation & purificationABSTRACT
The aim of the present work was to evaluate the usefulness of a simplified method for DNA extraction coupled to a nested-PCR protocol, based on the amplification of pneumolysin gene fragments for the diagnosis of pneumococcal pneumonia in pediatric patients with clinical and radiological evidence of bacterial infection. Bacterial DNA was extracted from sera by boiling and used without further purification in the PCR for the pneumolysin gene. None toxic reagents were used and the necessary steps to obtain the DNA were left at a minimum; furthermore, it overcomes the use of expensive commercial kits for DNA purification. The total procedure can be completed the same day of sampling and, most important, it avoids the use of sophisticated technology. Both in vitro analytical specificity and sensitivity (10 CFU/ml) of the assay were similar to those previously reported. When clinical samples were tested, the rate of positivity was shown to be 83.3% and 71% in pediatric patients with positive (group a) and negative blood cultures (group b), respectively. In group a, DNA detection was successful in samples from children without treatment or with less than 48 h of antibiotic therapy. None amplification was obtained from sera patients with viral infection or in samples from healthy controls. The application of the strategy described in this paper substantially seems to improve the diagnostic process in a determinate group: blood culture-negative children with pneumonia.
El objetivo del presente trabajo fue evaluar la utilidad de un método simplificado para extracción de ADN, acoplado a un protocolo de PCR anidada, basada en la amplificación de fragmentos del gen de la neumolisina para el diagnóstico de neumonía neumocócica en niños con evidencias clínicas y radiológicas de infección bacteriana. El ADN bacteriano fue extraído del suero por calentamiento y utilizado en la PCR para el gen de la neumolisina sin purificación posterior. Para la obtención de ADN no se utilizan reactivos tóxicos ni costosos "kits" comerciales. El procedimiento completo puede ser realizado en el día y lo que es más importante, evita el uso de tecnología sofisticada. La especificidad analítica in vitro y la sensibilidad (10 UFC/ml) del ensayo fueron similares a lo hallado en publicaciones anteriores. El porcentaje de muestras positivas fue del 83,3% y del 71% en los pacientes con hemocultivos positivos (grupo a) y negativos (grupo b), respectivamente. En el grupo a, sólo se obtuvieron resultados positivos mediante la PCR anidada en los pacientes no tratados o con menos de 48 hs de tratamiento antibiótico. No se obtuvieron señales de amplificación en los sueros de los pacientes con infecciones virales ni en las muestras del grupo control. La aplicación de la estrategia descripta incrementa la posibilidad diagnóstica de neumonía neumocócica en niños con hemocultivos negativos.
Subject(s)
Child, Preschool , Female , Humans , Infant , Male , Community-Acquired Infections/microbiology , DNA, Bacterial/isolation & purification , Pneumonia, Pneumococcal/microbiology , Polymerase Chain Reaction/methods , Streptococcus pneumoniae/isolation & purification , Bacteremia/microbiology , Community-Acquired Infections/diagnosis , Diagnosis, Differential , DNA, Bacterial/blood , DNA, Bacterial/genetics , Pneumonia, Bacterial/diagnosis , Pneumonia, Pneumococcal/diagnosis , Pneumonia, Viral/diagnosis , Sensitivity and Specificity , Streptococcus pneumoniae/geneticsABSTRACT
La fibrosis quística (FQ) se caracteriza por disfunciones en las glándulas de secreción exocrina del organismo. Las primeras manifestaciones suelen observarse en el sistema respiratorio, constituyendo una de las causas más importantes de morbimortalidad en los pacientes afectados. Los microorganismos patógenos que colonizan frecuentemente el tracto respiratorio de estos pacientes son Staphylococcus aureus, Haemophilus spp., y Pseudomonas aeruginosa. Entre noviembre de 2001 y agosto de 2004 se estudiaron 222 muestras respiratorias de pacientes con FQ de entre 4 meses y 11 años de edad. Se aislaron S. aureus (38,7%), P. aeruginosa (37,4%) y Haemophilus spp., (15,3%). En S. aureus la meticilina-resistencia fue del 25,9% y se asoció con altas resistencias a eritromicina (35,0%) y clindamicina (29,4%). El mayor porcentaje de resistencia observado en las cepas de P. aeruginosa fue frente a gentamicina (31,0%). Los aislamientos de Haemophilus spp. fueron resistentes a ampicilina (23,0%) debido a la presencia de beta-lactamasas, y a trimetoprima/sulfametoxazol (59,0%).
Cystic Fibrosis (CF) is characterized by a dysfunction of the exocrine secretion glands. The first symptoms often appear in the respiratory system which constitutes one of the most important morbimortality causes in these patients. Chronic respiratory tract colonization is caused mainly by bacteria such as Staphylococcus aureus, Haemophilus spp. and Pseudomonas aeruginosa. Respiratory samples from patients with CF (age group: 4 months to 11 years) were analyzed from November 2001 to August 2004. The most frequently isolated microorganisms were S. aureus (38.7%), P. aeruginosa (37.4%) and Haemophilus spp (15.3%). A high resistance to erithromycine (35.0%) and clindamicine (29.4%) was observed in S. aureus strains and 25.9% of them were methicillin-resistant. P. aeruginosa strains were mainly gentamicin-resistant (31.0%). The rate of ampicillin-resistant Haemophilus spp. was 23.0% and it was due to the presence of beta-lactamases, but a high trimethoprim-sulfamethoxazole resistance was observed in this microorganism (59.0%).
Subject(s)
Child , Child, Preschool , Female , Humans , Infant , Male , Bacteria/isolation & purification , Bacterial Infections/microbiology , Cystic Fibrosis/complications , Respiratory Tract Infections/microbiology , Bacterial Infections/etiology , Cystic Fibrosis/microbiology , Disease Susceptibility , Drug Resistance, Bacterial , Drug Resistance, Fungal , Fungi/drug effects , Fungi/isolation & purification , Haemophilus Infections/etiology , Haemophilus Infections/microbiology , Haemophilus/drug effects , Haemophilus/isolation & purification , Mycoses/etiology , Mycoses/microbiology , Pseudomonas Infections/etiology , Pseudomonas Infections/microbiology , Pseudomonas aeruginosa/drug effects , Pseudomonas aeruginosa/isolation & purification , Respiratory Tract Infections/etiology , Staphylococcal Infections/etiology , Staphylococcal Infections/microbiology , Staphylococcus aureus/drug effects , Staphylococcus aureus/isolation & purificationABSTRACT
A case of a healthy girl with a trauma in her right leg is described. Twelve hours later she developed fever and pain in the inguinal region. Two days later, she was admitted to the Hospital, and there, an aspiration of pus from the lymph node was performed, and this sample was sent for culture. The Gram smear showed gram-positive filamentous bacilli and when Kinyoun was used they were observed as weakly acid fast rods. After four days of incubation under aerobic conditions, white and hemolitic colonies were seen on human blood agar plates. Biochemical tests as urea hydrolysis and gelatin liquefaction were performed. To complete the identification it was sent to a reference laboratory, INEI-ANLIS Dr. Carlos G. Malbrán, where the isolate was confirmed as Nocardia asteroides sensu stricto. The patient was treated with intravenous cephalotin with good evolution. Therapy was followed with oral trimethoprim-sulfamethoxazole. This case is the first report of a Nocardia infection in the Hospital de Niños de Santa Fe. The fact that N. asteroides was isolated from an immunologically competent girl should be highlighted. This species is uncommon in children and it is rare in our region. In addition, N. asteroides infections are usually seen in pulmonary disease and rarely producing cutaneous infections.
Subject(s)
Humans , Male , Infant , Aeromonas/pathogenicity , Bacteremia/etiology , Cellulitis/etiology , Gram-Negative Bacterial Infections/etiology , Aeromonas/drug effects , Aeromonas/isolation & purification , Bacteremia/drug therapy , Ceftazidime/therapeutic use , Cellulitis/drug therapy , Cephalosporins/therapeutic use , Diarrhea, Infantile/etiology , Gram-Negative Bacterial Infections/drug therapyABSTRACT
En el presente trabajo se comunica el primer aislamiento de Salmonella Freetown en Argentina. Se obtuvo a partir de un coprocultivo de una paciente de 1 mes y 7 días, cuya madre consultó por un cuadro de diarrea aguda en el Hospital de Niños Dr. Ricardo Gutiérrez de la ciudad de Santa Fe. Por sus características bioquímicas y su fórmula antigénica, esta nueva serovariedad se ubica dentro de la especie Salmonella enterica subespecie enterica