Summary
Background. Shigella, a member of Enterobacterales family, is a gramnegative, nonmotile rod. It is a common cause of acute diarrheal disease called shigellosis. Shigella is highly infectious (a minimum inoculum of only 10–100 organisms) and is transmitted via the fecal- oral route. Phenotypically, Shigella spp. and E. coli share many com mon characteristics, yet they have separate entities in epidemiology and clinical disease, which poses a diagnostic challenge.
Clinical presentation. A 14-yearold girl was brought to Emergency Department by ambulance. The patient was presented with febrile fever (40 °C), nausea, general weakness and bloody diarrhoea. The patient was prescribed with ceftriaxone empirically, however, the antibiotic treatment was ineffective and it was decided to add metronidazole perorally. Rota virus, adenovirus and noro virus antigen tests results were negative, C. difficile toxins were negative, influenza antigens A and B were negative. Blood and stool cultures were also negative. Stool microscopy – a full screen of leucocytes and erythrocytes was observed. During abdominal ultra sound colitis signs were revealed. On the eighth day of hospitalization symptoms of noninfectious acute pericarditis have appeared. On the tenth day a Shigella flexneri 2a and Candida albicans were isolated from the bacterial culture. The treatment was changed to biseptol. After subdue of disease, the patient was discharged from hospital.
Conclusion. Shigella spp. and E. coli are very difficult to distinguish phenotypically, there fore a differential diagnosis must be done with out most care. Primary diagnostic method for shigellosis is culture on selective media. Negative culture does not rule out a possibility of shigellosis. MALDI-TOF MS can not differentiate between lactose negative E. coli and Shigella spp., so additional diagnostic methods must be applied in case of shigellosis suspicion.
