Ishiguro Fubito, Toho Miho, Yamazaki Mitsugu, Matsuyuki Seiko, Moriya Kazuo, Tanaka Daisuke, Isobe Junko, Kyota Yoshito, Muraoka Michio
Fukui Prefectural Institute of Public Health and Enviomental Science.
Kansenshogaku Zasshi. 2006 Sep;80(5):507-12. doi: 10.11150/kansenshogakuzasshi1970.80.507.
We studied 107 isolates of Escherichia coli O153 from sporadic diarrhea cases in Fukui, Toyama, Aichi, and Saga prefectures from 1991 to 2005 for antimicrobial susceptibility and mechanisms of fluoroquinolone resistance, based on standard disk diffusion. Of 12 drugs tested, ampicillin displayed resistance to 72.9% of isolates, streptomycin to 48.6%, tetracycline to 46.7%, sulfisoxazole to 46.7%, trimethoprim/sulfamethoxazole to 29.9%, nalidixic acid (NA) to 29.9%, and ciprofloxacin (CPFX) to 24.3%. Ten of 32 isolates resistant to 3-6 drugs and 16 of 18 isolates resistant to 7-10 drugs were resistant both to NA and CPFX. Mutations of amino acid in quinolone resistance-determining regions of gyrA and parC genes were detected in 24 isolates resistant both to NA and CPFX, and in 1 isolate resistant to NA. The former possessed a combination of double substitution (S83L and D87L) in GyrA and a single substitution (S80I) in ParC. Some 12 of 24 isolates possessed another single substitution (E84V or E84G or A108T) in ParC. The 25 isolates were classified into 4 types as follows. 1 isolate as type 1: GyrA (S83L) and ParC (S80I); 12 isolates as type 2: GyrA (S83L and D87N) and ParC (S80I); 8 isolates as type 3: GyrA (S83L and D87N) and ParC (S80I and E84G/S80R and E84V); and 4 isolate as type 4: GyrA (S83L and D87N) and ParC (S80I and A108T). In the relationship between amino acid mutations and minimal inhibitory concentrations (MIC) of fluoroquinolone, MICs of CPFX, ofloxacin, and norfloxacin showed 1microg/mL, 2microg/mL and 8microg/mL in type 1; 8 approximately 32microg/mL, 8 approximately 32microg/mL and 16 approximately 256microg/mL in type 2; and 32 approximately 256microg/mL' 32 approximately 128microg/mL and 128-->512microg/ mL in types 3 and 4. These results suggest that most of multiple-antimicrobial-resitant E. coli O153 isolates from sporadic diarrhea cases were resistant to fluoroquinolones and possessed mutations at gyrA and parC genes associated with fluoroquinolone resistance.
我们对1991年至2005年期间从福井、富山、爱知和佐贺县散发性腹泻病例中分离出的107株大肠杆菌O153进行了研究，采用标准纸片扩散法检测其对抗菌药物的敏感性以及氟喹诺酮耐药机制。在所检测的12种药物中，氨苄西林对72.9%的分离株耐药，链霉素对48.6%耐药，四环素对46.7%耐药，磺胺异恶唑对46.7%耐药，甲氧苄啶/磺胺甲恶唑对29.9%耐药，萘啶酸（NA）对29.9%耐药，环丙沙星（CPFX）对24.3%耐药。在对3 - 6种药物耐药的32株分离株中，有10株对NA和CPFX均耐药；在对7 - 10种药物耐药的18株分离株中，有16株对NA和CPFX均耐药。在对NA和CPFX均耐药的24株分离株以及对NA耐药的1株分离株中，检测到gyrA和parC基因喹诺酮耐药决定区的氨基酸突变。前者在GyrA中存在双重替换（S83L和D87L）以及在ParC中存在单一替换（S80I）。24株分离株中有12株在ParC中还存在另一种单一替换（E84V或E84G或A108T）。这25株分离株分为以下4种类型。1株为1型：GyrA（S83L）和ParC（S80I）；12株为2型：GyrA（S83L和D87N）和ParC（S80I）；8株为3型：GyrA（S83L和D87N）和ParC（S80I和E84G/S80R和E84V）；4株为4型：GyrA（S83L和D87N）和ParC（S80I和A108T）。在氨基酸突变与氟喹诺酮最低抑菌浓度（MIC）的关系中，CPFX、氧氟沙星和诺氟沙星的MIC在1型中分别为1μg/mL、2μg/mL和8μg/mL；在2型中分别为8至32μg/mL、8至32μg/mL和16至256μg/mL；在3型和4型中分别为32至256μg/mL、32至128μg/mL和128至512μg/mL。这些结果表明，散发性腹泻病例中大多数多重耐药性大肠杆菌O153分离株对氟喹诺酮耐药，并且在与氟喹诺酮耐药相关的gyrA和parC基因存在突变。
