[Epidemiological study of levofloxacin-resistant Streptococcus pneumoniae isolated from 2003 through 2006 in Japan].
We evaluated the usefulness of WHONET, free software from the World Health Organization (WHO), in a laboratory-based survey analyzing infectious disease, i.e., Streptococcus pneumoniae, and its antimicrobial susceptibility, i.e., to levofloxacin (LVFX), between 2003 and 2006 at 5 hospitals. The percentage of resistant strains (MIC > or = 8 microg/mL) isolated by the Maebashi Red Cross Hospital Laboratory between 2003 and 2005 was 3.8% (26/684 = number of resistant isolates/number of all isolates), significantly higher (p<0.001, Fisher's exact test) than the 0.5% (8/1717) recorded at 4 other hospital laboratories. In 2006 the Maebashi Red Cross Hospital Laboratory percentage of resistant strains was 0.9% (2/221) in the absence of intervention to reduce the percentage of resistant isolates, while that at 4 other hospital laboratories was 1.3% (9/ 717)--a difference not statistically significant (p = 0.574). Of resistant strains, 86% (24/28) came from patients older than 67 years and 71% (20/28) from outpatients or those newly hospitalized 1 or 2 days. Where and when pathogens are isolated are the two priority factors in epidemiological analysis. Superimposing plot of patient residences and isolated times of LVFX-resistant S. pneumoniae strains for each incidences showed no unusual trends in pathogen distribution. Analysis of possible multiple drug resistance for all LVFX-resistant S. pneumoniae isolates, i.e., resistance profile determination, indicated that no strain isolated in any one-month period shared an identical resistance profile, suggesting that the probability of a community outbreak of one specific S. pneumoniae strain is minimal. We did not find possible causes for the high resistance percentage of isolates recorded by the Maebashi Red Cross Hospital Laboratory during 2003-2005, or for the low resistance percentage for strains isolated during 2006. Analysis of our survey indicated that LVFX-resistant S. pneumoniae isolates are still rare in the communities tested, but ongoing surveys have keenly aroused public interest in potential risk and the consequences of the increase in antibiotic-resistant pathogens. This study showed WHONET to be indispensable as an epidemiological investigation tool.
Division of Clinical Microbiology, Department of Clinical Laboratory, Maebashi Red Cross Hospital.
Maemi
M
Sohma
Ikuyo
I
Yokozawa
Shingaku
S
Kaneko
Sachiko
S
Satake
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D024881:Drug Resistance, Bacterial; D004812:Epidemiologic Methods; D006801:Humans; D007564:Japan / Q000453:epidemiology; D064704:Levofloxacin; D008875:Middle Aged; D015242:Ofloxacin / Q000494:pharmacology*; D011008:Pneumococcal Infections / Q000453:epidemiology*; D012984:Software; D013296:Streptococcus pneumoniae / Q000187:drug effects* / Q000302:isolation & purification*
D000900:Anti-Bacterial Agents; D064704:Levofloxacin; D015242:Ofloxacin