a Department of Laboratory Medicine and b Department of Medicine, National University Hospital, 5 Lower Kent Ridge Road, Singapore 119074
Sir,
Penicillin resistance in Streptococcus pneumoniae is a serious problem among hospitalized patients in the Asia Pacific region.1 Levofloxacin, a broad-spectrum fluoroquinolone with both intravenous and oral preparations,2 was recently approved by the US Food and Drug Administration with the specific indication for community-acquired pneumonia caused by penicillin-resistant pneumococci. Levofloxacin has not been introduced to the National University Hospital formulary so far. However, ciprofloxacin and other fluoroquinolones have been in use for the past decade.
We studied 33 consecutive clinical isolates of S. pneumoniae from January to March 2000. MICs of levofloxacin were determined using the Etest method, a technique that has been validated to be accurate for susceptibility testing of S. pneumoniae.3 NCCLS criteria were used for interpretation of antibiotic susceptibility tests. ATCC strain 29213 was used as a quality control.
MIC50 and MIC90 for penicillin were 0.23 and 3.8 mg/L respectively, compared with 0.75 and 1.00 mg/L for levofloxacin. The list of MIC values, percentage susceptible and resistant are shown in Table I for penicillin and in Table II
for levofloxacin.
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This study suggests that while levofloxacin might be a useful agent in the initial therapy of suspected community-acquired penicillin-resistant pneumonia, there has to be a high level of vigilance to the emergence of levofloxacin resistance even in communities where this drug is not clinically available.
Notes
J Antimicrob Chemother 2000; 46: 862863
References
1 . Song, J. H., Lee, N. Y., Ichiyama, S., Yoshida, R., Hirakata, Y., Fu, W. et al. (1999). Spread of drug-resistant Streptococcus pneumoniae in Asian countries: Asian network for surveillance of resistant pathogens (ANSORP) study. Clinical Infectious Diseases 28, 120611.[ISI][Medline]
2 . Wimer, S. M., Schoonover, L. & Garrison, M. W. (1998). Levofloxacin: a therapeutic review. Clinical Therapy 20, 104970.
3
.
Rowe, A. K., Schwartz, B., Wasas, A. & Klugman, K. P. (2000). Evaluation of the Etest as a means of determining the antibiotic susceptibilities of isolates of Streptococcus pneumoniae and Haemophilus influenzae from children in the Central African Republic. Journal of Antimicrobial Chemotherapy 45, 1323.
4 . Barry, A. L. & Fuchs, P. C. (1991). Cross-resistance and cross-susceptibility between fluoroquinolone agents. European Journal of Clinical Microbiology and Infectious Diseases 10, 10138.[ISI][Medline]
5
.
Smith, K. E., Besser, J. M., Hedberg, C. W., Leano, F. T., Bender, J. B., Wicklund, J. H. et al. (1999). Quinolone-resistant Campylobacter jejuni infections in Minnesota, 19921998. New England Journal of Medicine 340, 152532.
6
.
Ho, P. L., Que, T. L., Tsang, D. N., Ng, T. K., Chow, K. H. & Seto, W. H. (1999). Emergence of fluoroquinolone resistance among multiply resistant strains of Streptococcus pneumoniae in Hong Kong. Antimicrobial Agents and Chemotherapy 43, 131013.