Forty-one strains of Streptococcus pneumoniae were isolated at Seoul National University Children's Hospital from 1991 to 1997. Isolates were divided into six groups based on MICs of three quinolones, ciprofloxacin, ofloxacin and norfloxacin. Sequencing showed that the isolates which were intermediately resistant to three quinolones or resistant to at least one kind of quinolone had one missense mutation, Lys137-->Asn(AAG-->AAT) substitution in the ParC subunit of topoisomerase IV without additional mutation in QRDR of the GyrA subunit of DNA gyrase. In conclusion, the ParC subunit of DNA topoisomerase IV is the primary target site for fluoroquinolone in S. pneumoniae and Lys137-->Asn substitution renders the quinolone resistance in S. pneumoniae.
DNA Topoisomerase (ATP-Hydrolysing)/genetics* ; Drug Resistance, Microbial/genetics* ; Human ; Isoenzymes/genetics* ; Mutation/genetics* ; Quinolones* ; Streptococcus pneumoniae/genetics

Primary diffuse large B-cell lymphoma (DLBCL) of the female genital tract is a rare case. It is hard to diagnose DLBCL of the uterine cervix before surgery because it is often misdiagnosed as cervical myoma or cervical squamous cell carcinoma. Here, we report a case of cervical DLBCL misdiagnosed as a cervical myoma. A 48-year-old premenopausal woman was referred to the gynecology department due to abnormal uterine bleeding with a normal Papanicolaou smear. The initial diagnosis according to ultrasound and computed tomography was a cervical myoma. She had undergone a hysterectomy with bilateral salpingectomy. The final diagnosis was cervical DLBCL and she was referred to the department of hematology for treatment with Rituximab combined chemotherapy. After six courses of chemotherapy, complete remission was reached. At a 2-year follow-up, the patient is alive without interval change.