Invasive Pneumococcal Infections: A Comparison Between Adults and Children

Abstract

A similar number of adults and children had invasive pneumococcal infection. There was male predominance, and different ethnic distribution between children and adults. The majority of adults (78%), had underlying diseases, but this was less frequent in children (24%). The presenting illness differed between adults and children. Complications of invasive pneumococcal infection occurred more frequently in adults than in children. The mortality rate in adults was 21.5%; in children, only 3.8%. The rate of penicillin-resistant pneumococci at our hospital was 23%, while cefotaxime resistance was 4.2%. Penicillin-resistant pneumococci were not isolated more frequently from children than from adults. Patients with penicillin-resistant pneumococci had longer duration of hospitalization and more nosocomially acquired infections. No difference in the mortality rate was found between patients with resistant or sensitive pneumococci. Ninety-five percent of strains were included in the current vaccine, but less than 2% of patients had been vaccinated. Isolates prevalent in Europe and the United States (19, 5, 1, 14, 6, 18, 12, 4, 9, 23, 7) were also most prevalent in Jerusalem. The distribution of serotypes differed between children and adults, and between patients from whom resistant organisms were isolated as opposed to sensitive organisms.

Influence of Patient Age on Streptococcus pneumoniae Serotypes Causing Invasive Disease

“…Socioeconomic and geographical differences do not explain our results for a homogeneous patient population living in the same geographical area (11). Year-to-year variation in serotype distribution was not a factor in our study or in other studies of infections over time (20,30). Furthermore, antibiotic resistance due to preventive-antibiotic use in special-risk populations (26) and underlying immune system abnormalities such as those due to HIV infection (19) were also ruled out as an explanation for our results for different age groups.…”

“…Several studies have shown that serotype 3 is a frequent isolate from the respiratory tract (10,12) but an infrequent cause of invasive S. pneumoniae infections in children (17,20,23). In a recent study of invasive infections in children under 5 years of age in Santiago, Chile, serotype 3 caused only 3.3% of infections (three-pneumonias) (15).…”

“…Some studies suggest that different serotypes cause infections in different age groups (20). We had an opportunity to explore this possibility further in a relatively homogenous patient population without HIV infection, where pneumococcal antibiotic resistance was not a factor during the 5-year study period.…”

Absence of leukocytosis in bacteraemic pneumococcal pneumonia

“…Despite all rigorous definitions of pneumonia requiring the finding of a pulmonary infiltrate on a chest radiograph, 5,6,[12][13][14] in daily practice in patients with mild respiratory symptoms and a normal WBC count a chest radiograph will often not be ordered.…”

“…8,13 However, as many as 30% of patients might have an atypical illness, demonstrating the clinical variability of bacteraemic pneumonia. 7 As shown previously by Toikka et al 7 and confirmed in our study, 17% of children presented with normal WBC on admission.…”