Colonização nasofaríngea pelo Streptococcus pneumoniae em crianças com doença falciforme usando penicilina profilática

Abstract

Objectives: To determine the prevalence of nasopharyngeal pneumococcus colonization in children with sickle cell disease undergoing penicillin prophylaxis, to identify risk factors for colonization and to serotype and determine antibiotic resistance in pneumococci obtained from those children. Between April 9, 2002 and February 28, 2003, 188 nasopharyngeal swabs were obtained from 98 children with sickle cell disease in follow-up at the Hospital São Paulo Universidade Federal de São Paulo. Pneumococci were isolated and identified by standard methods. The minimal inhibitory concentration for penicillin was determined by the E-test method. Isolates were serotyped with the use of type-specific antisera for 46 different serotypes (Neufeld-Quellung reaction). Methods:Results: The age of children ranged from 4 months to 17 years (median and standard deviation 6.8±4.7 years). Thirteen of the 98 children had nasopharyngeal pneumococcus colonization (13.3% prevalence). There was a significantly greater risk of colonization among children less than 2 years old (p = 0.02). Twenty-one percent of isolates had intermediate penicillin resistance. There were no isolates highly resistant to penicillin. All isolates were susceptible to erythromycin, ceftriaxone, or vancomycin. The most frequently identified serotypes were 18C and 23F.Conclusions: Penicillin prophylaxis reduced pneumococcal nasopharyngeal colonization and did not increase the prevalence of penicillin-resistant pneumococci in children with sickle cell disease. Penicillin can be used not only for prophylaxis, but also in the acute management of febrile states with these children.

Penicillin Resistance in Nasopharyngeal <i>Streptococcus pneumoniae</i> among Children with Sickle Cell Disease Immunized with 7-Valent Pneumococcal Conjugate Vaccine

“…Patients with HbSC and HbSβ + should demonstrate better preserved splenic function in the first five years of life than patients with HbSS and HbSβ, determining a better immune response, and therefore, lower risk of invasive pneumococcal disease [24]. Verifying if colonization rate could also be different according to genotypes, we found no difference in the multivariate analysis, which was also observed in previous studies [6,17].…”

“…Other authors found colonization rates among children with SCD taking penicillin ranging from 8% to 15.5% [11,17,18]. In the Brazilian study published in 2005, we found similar results, with a colonization rate of 13.3% [6]. In none of these studies, patients received the PCV 7.…”

“…Some studies suggest that the age of the child interferes with the prevalence of colonization by Streptococcus pneumoniae, with more colonization among children under two years [22,23]. Evaluating children with SCD, some authors have also obtained the same result [6,17], but in this study, the age of 24 months was not a risk factor for nasopharyngeal colonization.…”

“…The 23-valent pneumococcal polysaccharide vaccine does not affect nasopharyngeal colonization [5,6], differing from the PCV 7, which decreases the colonization by the vaccine serotypes [7,8].…”

Medidas gerais no tratamento das doenças falciformes

“…Entre os defeitos imunológicos descritos estão: diminuição da produção de interleucina 4, com comprometimento da maturação do linfócito B e da produção de IgM; contagem variável de linfócitos T helper e supressor; redução nos níveis de linfócitos T helper e supressor nos pacientes com asplenia funcional; rápida multiplicação bacteriana no sangue devido aos altos níveis de ferro e transferrina circulantes; produção de Acs inadequada frente a administração EV de vacinas polissacarídica. 25,27,28 A alteração da função esplênica nesses pacientes determina além da perda da capacidade de filtração mecânica, a diminuição da opsonização por menor síntese de opsoninas e pela alteração funcional da via alternativa e clássica do complemento, resultando em fagocitose e morte intracelular ineficazes, principalmente para as bactérias encapsuladas 29 O risco da criança falciforme adquirir infecção pelo pneumococo quando comparado com a população normal é trinta a cem vezes maior para bacteremia e quatrocentas vezes maior para sepse ou meningite; já em relação ao hemófilus o risco é cerca de duas a quatro vezes maior. 28,30,31 Esses pacientes também são mais susceptíveis a infecções por Salmonella sp e germes gram negativos.…”