Objective: To investigate an association between the gut microbiome and efficacy of poly(ADP-ribose) polymerase inhibitors (PARPi) in ovarian cancer. Methods: This study conducted fecal microbiome analysis (16S rRNA gene sequencing) and circulating tumor DNA (ctDNA) profiling for ovarian cancer patients who underwent PARPi maintenance therapy. Fecal and blood samples were collected at the baseline and the progressive disease (PD) or last follow-up. The relative abundance of gut microbes and progression-free survival (PFS) were analyzed using linear discriminant analysis of effect size and the Cox proportional hazard model according to BRCA1/2 mutation (BRCA1/2mut) status detected by ctDNA sequencing. Results: Baseline samples were available from 23 BRCA1/2mut-positive patients and 33 BRCA1/2mut-negative patients. The microbes enriched in the baseline samples with long PFS were Bifidobacterium, Roseburia, Dialister, Butyricicoccus, and Bilophila for BRCA1/2mut-positive patients and Phascolarctobacterium for BRCA1/2mut-negative patients. In multivariate analyses dividing patients by the median values of relative abundances, no bacteria were associated with PFS in BRCA1/2mut-positive patients, whereas high Phascolarctobacterium abundances (≥1.11%) was significantly associated with longer PFS in BRCA1/2mut-negative patients (median 14.0 vs. 5.9 months, hazard ratio=0.28; 95% confidence interval=0.11–0.69; p=0.014). In the last samples, the relative abundances of Phascolarctobacterium were significantly higher in patients without PD (n=5) than those with PD (n=15) (median 1.25% vs. 0.06%; p=0.016). Conclusion High fecal composition of Phascolarctobacterium was associated with prolonged PFS in patients with BRCA1/2mut-negative ovarian cancer receiving PARPi therapy. Our results would provide new insights for future research.

BACKGROUND:Splenectomy in patients with liver cirrhosis (LC) is expected to become more common owing to its efficacy on portal hemodynamics. In this report we describe an alarming case of group B streptococcus (GBS) infection after splenectomy in a patient with LC. METHODS:A 72-year-old woman with a history of LC was admitted to our emergency department because of respiratory failure. The patient had received left lateral segmentectomy of the liver and splenectomy three months before admission. Pulmonary examination revealed significant wheezing during inspiration and expiration, but no crackles and stridor. Chest radiography and CT showed no infiltrates. A presumptive diagnosis of bronchial asthma caused by upper respiratory infection was made. Four days after admission, GBS infection was confirmed by blood culture and penicillin G was administered. Antibiotics were given intravenously for a total of 12 days. RESULTS:The patient was discharged on the 12th day after admission. CONCLUSIONS:Although efficacy of splenectomy in patients with LC has been reported, immune status should be evaluated for a longer period. Patients who have undergone splenectomy are highly susceptible to bacteria; moreover, LC itself is an independent risk factor for mortality in patients with sepsis. Since prophylaxis against GBS has not been established, immediate action should be taken. Emergency physicians should be aware of invasive GBS infection in the context of the critical risk factors related to splenectomy and LC, particularly the expected increase of splenectomy performed in LC patients.