The incidence of invasive infections caused by S. pneumoniae in Taiwan is still unknown, although several studies regarding invasive pneumococcal infections in adults and children have been reported (9,13–19). The overall mortality rate (42.5%) for elderly patients (>65 years of age) with invasive infections (bacteremia, pneumonia, pleural empyema, meningitis, septic arthritis, and peritonitis) was higher than the rates for patients 19–64 years of age (22.4%) and for children (8.1%) (9). Some factors, such as the presence of serotype 3 strain, shock as initial presentation, and multilobar pneumonia, were significantly associated with death from invasive infections (14,15). Another report from central Taiwan indicated that the overall mortality rate for children with invasive pneumococcal infections was 20.3%, and in 53.3%, the infections progressed rapidly to death (18). Other studies found that 70% to 80% of adult patients with invasive pneumococcal disease had underlying diseases (malignancies, followed by congestive heart failure and diabetes mellitus) (14,15). Patients with HIV infection or multiple myeloma in whom invasive pneumococcal infection developed were extremely rare (14,13–20). No significant difference was found in the mortality rates of patients with penicillin-susceptible (PSSP) and those with penicillin-nonsusceptible S. pneumoniae (PNSSP) infections (9,14,15,18).

The prevalence of this organism that causes community-acquired pneumonia or meningitis in adults or children is obscure. Several reports have indicated that this organism causes 19% to 33% of infections that results in bacterial meningitis in children (21–23). In one study of adult patients, 28% of the community-acquired bacterial meningitis were caused by S. pneumoniae, the highest proportion after that was by Klebsiella pneumoniae (33%) (24). The incidence (cases per 100,000 emergency visits) of pneumococcal meningitis at National Taiwan University Hospital was 2.8 in 1997–1998 (24). In other study, S. pneumoniae accounted for 21.8% of bacterial pathogens isolated from middle ear fluid from 243 children with acute otitis media (25).

A high dose of intravenous penicillin G is still recommended as one of the primary drugs of choice for the empirical treatment of patients with community-acquired pneumonia who need hospitalization because about 10% of our clinical isolates have an MIC of penicillin of ≥4 μg/mL (6–10,39). MIC testing, mostly by the E-test, for penicillin-nonusceptible (oxacillin 1-μg disk) isolates recovered from respiratory secretion or blood specimens from patients without meningitis, is always performed in most teaching hospitals in Taiwan (39, 40). Obviously, the guidelines for the treatment of community-acquired pneumonia in adults recommended by the American Thoracic Society in 2001 (41) and the Infectious Diseases Society of America in 2000 (42), as well as suggestions for the management of sinusitis, otitis media, and chronic bronchitis, which include one macrolide alone as the drug of choice or as an alternative antimicrobial agent, are inappropriate in Taiwan. This is because of the high incidence of macrolide resistance and the high proportion of MLSB-phenotype among these resistant isolates.

Figure 2

Figure 2. Distribution of six major serogroups or serotypes of clinical isolates of Streptococcus pneumoniae, Taiwan, 1984–1998.

Figure 2 illustrates the distribution of six major serogroups or serotypes of S. pneumoniae isolates from 1984 to 1998 (4,6,7,9,19,43). The frequencies of serogroups (serotypes) 23 (23F) and 19 (19F) increased remarkably, whereas those of serotypes 14, 3, and 1 declined. Some unusual serotypes (serotypes 20, 11, 7, and 8) appeared to emerge in southern Taiwan. No relationship was found between the serogroup or serotype distribution of isolates and the patients’ ages (p >0.05) (6,7,9). PNSSP exhibited resistance to isolates from various serogroupsor serotypes. Among them, serogroups 11 and 23 isolates had the highest incidence of penicillin nonsusceptibility and multidrug resistance. However, serotype 3 isolates (0%–22%) and serotype 20 (11%) isolates had lower rates of nonsusceptibility to penicillin (4,6,9,19). In general, more than 90% of isolates causing invasive infections were included in the serogroups or serotypes covered by the 23-valent pneumococcal and 7-valent conjugate vaccine (4,9).

Before 1995, few regulations regarding antibiotic use existed for physicians in primary care clinics or hospitals. Furthermore, many antibiotics could easily be obtained at drugstores without a prescription. Although the medical payment has been regulated by the National Health Insurance program, implemented in Taiwan in 1995, antibiotics are still commonly used and seem to be overprescribed in primary care units (44). From 1996 to 1999, about 12% to 14% of total patient-visits in primary care units had antibiotic use. The common cold (32.3%) was the most frequent diagnosis for which antibiotics were prescribed. Penicillins (35.4%), cephalosporins (26.5%), and macrolides (21.6%) were the most commonly prescribed classes of antibiotics (44). In 1999, a reported point prevalence rate of about 7.5% among healthy high school students and healthy ambulatory elderly persons who had antimicrobial activity in their urine suggested that this may be the baseline for antibiotic use in the community (45). Surprisingly, over half of the patients who came to the emergency department of a large teaching hospital in Taiwan had taken antibiotics within the previous 12–48 hours. With the increasing and highly selective pressure of antibiotic usage in our community, the crisis of resistance continues to exist.

In the new millennium, the Center for Disease Control under the Department of Health in Taiwan has made nationwide surveillance of antimicrobial resistance and strict control of antibiotic usage major tasks. The new regulations for antibiotic prescription, established by the Bureau of National Health Insurance in 2001 (44), restrict the inappropriate use of the so-called first-line antibiotics (first-generation cephalosporins, macrolides, and gentamicin) for treating various infections, particularly the trivial upper respiratory tract infection. The use of the 23-valent pneumococcal vaccine, especially among high-risk adults and older persons, is encouraged, and new protein-conjugate vaccines will be introduced in the near future.

Taiwan has one of the highest levels of antibiotic resistant pneumococcus in the world. With the increase in international travel, the interchange of resistant clones among countries is unavoidable and the widespread distribution of these clones is expected. Strategies to limit the upsurge of resistant pneumococcus include improved surveillance, reduced antibiotic usage, and increased vaccination of persons at high risk. The judicious use of antimicrobial agents is necessary to avoid providing a selective advantage for resistant organisms. The active surveillance of resistant organisms can help track local resistance problems, prevent the future dissemination of these organisms, and provide options appropriate for empiric therapy.