Objectives:

To find out the prevalence and seasonal distribution of pneumococcal bacteraemia and the serotypes and antibiotic sensitivity of isolates.

Material and methods:

Retrospective study based on the records of our Microbiology Department with a focus on serotypes and MICs of pneumococcal strains isolated from adult and children with bacteraemia. Serotyping was performed by a Quellung technique in the National Reference Center. Sensitivity tests were performed by agar dilution following NCCLS criteria. Proportions comparison was performed by squared chi test.

Results:

The average number of pneumococcal isolates in blood culture was 29/year which accounts for a 7% of all significant bacteraemias and a near 2/1000 admissions. A 62% of cases occurred from December to May. A total of 70% of patients were male. Age distribution was: 18.7% isolated from infants 0–2 years; 10.3% from children 3–15 years; 45.7% from patients 16–65 years; and 25.3% from patients >66 years. Nine serotypes (14, 19, 3, 6, 1, 8, 18, 9, and 4) account for near 75% of isolates. A total of 82% of serotypes were isolated from children under 2 years. Similarly, 96% of serotypes from patients >65 years are included in the polysacharide vaccine. The 33% of isolates showed a reduced sensitivity to penicillin (22% intermediate resistance and 11% resistant), 19% showed a reduced sensitivity to cefotaxime (16% intermediate resistance and 3% resistant). A 22% of isolates were resistant to erithromycin; 29% to tetracycline; 17% to cloramfenicol. All isolates were susceptible to vancomicine. Strains from children under 2 years were more resistant to antimicrobials, being this difference os statistical meaning (P < 0.05), standing out figures of 59% with reduced sensitivity to penicillin, 38% with reduced sensitivity to cefotaxime, and 43% resistant to erithromicin. No statistical difference was obtained between tetraciclina resistance proportion in the different age groups (P = 0.215).

Conclusions:

In our environment, S. pneumoniae bacteraemia is found mainly in adult males. We found a high prevalence of strains with a certain degree of resistance to penicillin (33%), highlighting a 59% of resistant isolates from infants. The majority of serotypes from invasive infections are included in the current available vaccines.