Antibiotic sensitivity and serotypes of S. pneumoniae isolates in blood culture during a 12-year period in a community-based hospital in Madrid, Spain
Abstract number: 902_p1152
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.
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 02 years; 10.3% from children 315 years; 45.7% from patients 1665 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).
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."
|Session name:||XXIst ISTH Congress|
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