Shigella sonnei bacteraemia in a cystic fibrosis patient: case report and literature review

>INTRODUCTION: Shigellosis has a gastrointestinal presentation of variable severity in which bacteraemia is uncommon. We describe the first reported case of Shigella sonnei bacteraemia and intestinal coinfection with Clostridioides difficile in a cystic fibrosis patient. The literature on S. sonnei bacteraemia in adult and paediatric populations is also reviewed. CASE PRESENTATION: A 29-year-old male with cystic fibrosis presented with profuse acute watery diarrhoea, abdominal pain, shivering and fever. The patient showed mixed cardiogenic and septic shock. Despite antibiotic therapy, volume replacement therapy and vasoactive drugs, the patient showed biventricular dysfunction and multiple organ failure requiring implantation of an intra-aortic balloon pump (IABP) with extracorporeal membrane oxygenation (ECMO). C. difficile and S. sonnei were detected in the stools. Escherichia coli was identified in the blood by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry, although after re-evaluation with biochemical and antiserum agglutination tests, the isolate was confirmed as S. sonnei. After adjustment of the antibiotic therapy to vancomycin, meropenem, amikacin and metronidazole and continuing with ECMO and IABP support for 8 days, the patient improved and was finally discharged after 44 days. CONCLUSION: S. sonnei bacteraemia is an unusual entity that should be kept in mind because of the severity of its presentation and high mortality. In acute gastroenteritis and fever, especially in paediatric patients under 5 years old and adults with criteria for immunosuppression or chronic diseases, blood and stool cultures provide simple information that is nonetheless very important for the management and prognosis of these patients.