Dissemination of ST131 and ST393 community-onset, ciprofloxacin-resistant Escherichia coli clones causing urinary tract infections in Korea.
OBJECTIVE
Ciprofloxacin-resistant Escherichia coli is growing concern in clinical settings. In this study, we investigated the distribution of virulence determinants and phylogenetic groups among community-onset, ciprofloxacin-resistant E. coli isolates causing urinary tract infections (UTIs) in Korea. In addition, the evidence of clonal spread in the community was also examined.


METHODS
From November 2006 to August 2007, 543 community-onset E. coli isolates causing UTIs were collected as part of a multicenter surveillance study. In vitro susceptibility testing was performed using broth microdilution method. Distribution of virulence determinants and phylogenetic groupings were examined. In addition, multilocus sequence typing (MLST) analysis was performed.


RESULTS
In vitro antimicrobial susceptibility testing revealed that 154 isolates (28.4%) were ciprofloxacin-resistant. Of these, 129 ciprofloxacin-resistant E. coli isolates were further characterized. As a result of phylogenetic subgrouping, we found that phylogenetic subgroup D was the most predominant (46 isolates, 35.7%), followed by B2 (44 isolates, 34.1%), A (21 isolates, 16.3%), and B1 (18 isolates, 14.0%). MLST analysis showed 48 sequence types (STs). The most prevalent ST was ST131 (32 isolates, 24.8%), followed by ST393 (23 isolates, 17.8%). While all ST131 isolates belonged to phylogenetic subgroup B2, which is known to be a highly virulent, all ST393 isolates belonged to subgroup D. ST131 and ST393 showed different profiles of virulence factors; papA, papG allele III, and traT genes were significantly more prevalent in ST131 than in ST393 (p values, <0.001).


CONCLUSIONS
Based on genotyping, it is suggested that epidemic and virulent ciprofloxacin-resistant E. coli clones such as ST131 and ST393 have disseminated in Korea. However, the diversity of CTX-M genes in ST131 isolates may indicate that ESBL genes have been acquired independently or several ESBL-producing, ciprofloxacin-resistant E. coli clones may have disseminated in the Korean community.
Lee
Mi Young
MY
Asian-Pacific Research Foundation for Infectious Diseases (ARFID), Seoul, South Korea.
Choi
Hyeon Jin
HJ
Choi
Ji Young
JY
Song
Minsuk
M
Song
Yoosuk
Y
Kim
Shin-Woo
SW
Chang
Hyun-Ha
HH
Jung
Sook-In
SI
Kim
Yeon-Sook
YS
Ki
Hyun Kyun
HK
Son
Jun Seong
JS
Kwon
Ki Tae
KT
Heo
Sang Taek
ST
Yeom
Joon-Sup
JS
Shin
Sang Yop
SY
Chung
Doo Ryeon
DR
Peck
Kyong Ran
KR
Song
Jae-Hoon
JH
Ko
Kwan Soo
KS
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D015373:Bacterial Typing Techniques; D002939:Ciprofloxacin / Q000494:pharmacology*; D016000:Cluster Analysis; D017714:Community-Acquired Infections / Q000453:epidemiology / Q000382:microbiology; D016172:DNA Fingerprinting; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D024881:Drug Resistance, Bacterial; D004926:Escherichia coli / Q000145:classification / Q000187:drug effects*; D004927:Escherichia coli Infections / Q000453:epidemiology* / Q000382:microbiology; D029968:Escherichia coli Proteins / Q000235:genetics; D005838:Genotype; D006801:Humans; D008826:Microbial Sensitivity Tests; D017720:Molecular Epidemiology; D010802:Phylogeny; D056910:Republic of Korea / Q000453:epidemiology; D017422:Sequence Analysis, DNA; D014552:Urinary Tract Infections / Q000453:epidemiology* / Q000382:microbiology; D037521:Virulence Factors / Q000235:genetics
D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; D037521:Virulence Factors; D002939:Ciprofloxacin