Urinary tract infections (UTI) are mostly caused by bacteria. Urine cultures are usually a definitive measure to select the appropriate antibiotics for the elimination of a uropathogen and subsequent recovery from the infection. However, the preferred antibiotics as determined by urine culture and sensitivity may still not eliminate the infection and would require further examination to ascertain the cause of treatment failure which could be unresolved bacteriuria, bacterial persistence, immediate reinfection with a different uropathogen or misdiagnosis. A 2-years 7 months-old female was admitted in the Regional hospital of Buea following persistent fever. An auto medication with amoxicillin was reported. Urinalysis was done on the first day and the sediment of the cloudy urine revealed many bacteria and few pus cells. Ceftriaxone was prescribed as empirical treatment and a request for urine and blood culture was made. Three days after admission, the temperature and CRP were 39.0 °C and 96 mg/l, respectively. The urine culture results (> 105 CFU/ml of Shigella flexneri sensitive to ofloxacin) were presented to the doctor on the 4th day of admission. Patient was put on ofloxacin. Three days after, the temperature (38.5 °C) and CRP (24 mg/l) were still elevated. The blood culture result came out negative. A second urine culture was requested which came back positive (> 105 CFU/ml of Escherichia coli resistant to ofloxacin and sensitive to meropenem and amikacin). Ofloxacin was discontinued and the patient put on meropenem and amikacin. The third urine culture recorded no significant growth after 48 h of incubation. The patient was discharged looking healthy once more with a normal body temperature. Antibiotics tailored towards the elimination of a particular bacterial species may as well provide a favorable environment for other bacterial species that are resistant to it in the course of treating a UTI episode. This apparent treatment failure may first of all require a second urine culture for confirmation rather than considering the possibilities of a misdiagnosis.

中文翻译：

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尿路致病菌从弗氏志贺氏菌迅速转移到大肠埃希氏菌的病例报告：细菌持久性和再感染之间的细线。

尿路感染（UTI）主要由细菌引起。尿培养通常是选择适当的抗生素消除尿路致病菌并随后从感染中恢复的决定性措施。但是，通过尿液培养和敏感性确定的首选抗生素可能仍不能消除感染，并且需要进一步检查以确定治疗失败的原因，可能是未解决的细菌尿，细菌持续存在，立即用不同的尿路致病原再次感染或误诊。持续发烧后，一名2岁7个月大的女性在布阿地区医院住院。据报道使用阿莫西林的自动药物治疗。第一天进行尿液分析，浑浊的尿液沉积物显示出许多细菌和少量脓细胞。头孢曲松被指定为经验治疗药物，并要求进行尿液和血液培养。入院三天后，温度和CRP分别为39.0°C和96 mg / l。入院第4天将尿培养结果（> 105 CFU / ml对氧氟沙星敏感的志贺氏志贺菌）提交给医生。患者服用氧氟沙星。三天后，温度（38.5°C）和CRP（24 mg / l）仍然升高。血液培养结果阴性。要求进行第二次尿液培养，然后恢复阳性（> 105 CFU / ml对氧氟沙星耐药，对美洛培南和丁胺卡那霉素敏感的大肠杆菌）。停用氧氟沙星，患者服用美罗培南和丁胺卡那霉素。孵育48小时后，第三次尿液培养物未见明显生长。患者恢复出院，体温恢复正常，看上去又健康。专为消除特定细菌物种而设计的抗生素也可以为在治疗UTI发作过程中对其产生耐药性的其他细菌物种提供有利的环境。这种明显的治疗失败可能首先需要进行第二次尿培养以进行确认，而不是考虑误诊的可能性。