New fecal microbiota for cancer patients: The composition of the gut microbiome influences the response of cancer patients to immunotherapies. Baruch et al. and Davar et al. report first-in-human clinical trials to test whether fecal microbiota transplantation (FMT) can affect how metastatic melanoma patients respond to anti–PD-1 immunotherapy (see the Perspective by Woelk and Snyder). Both studies observed evidence of clinical benefit in a subset of treated patients. This included increased abundance of taxa previously shown to be associated with response to anti–PD-1, increased CD8 ⁺ T cell activation, and decreased frequency of interleukin-8–expressing myeloid cells, which are involved in immunosuppression. These studies provide proof-of-concept evidence for the ability of FMT to affect immunotherapy response in cancer patients. Science , this issue p. 602 , p. 595 ; see also p. 573

During a Brazilian multicentric antimicrobial resistance surveillance study, colistin resistance was investigated in 4,620 Enterobacteriaceae isolated from human, animal, food and environmental samples collected from 2000 to 2016. We present evidence that mcr-1-positive Escherichia coli has been emerging in South America since at least 2012, supporting a previous report on the possible acquisition of mcr-1-harbouring E. coli by European travellers visiting Latin American countries.

The detection and rapid spread of colistin-resistant Enterobacteriaceae carrying the mcr-1 gene has created an urgent need to strengthen surveillance. In this study, eight clonally unrelated colistin-resistant Escherichia coli isolates carrying mcr-1 and bla _CTX-M or bla _CMY-2 genes were isolated from commercial chicken meat in Brazil. Most E. coli strains carried IncX4 plasmids, previously identified in human and animal isolates. These results highlight a new reservoir of mcr-1 -harboring E. coli strains in South America.

A colistin-resistant Escherichia coli strain was recovered from a patient with a diabetic foot infection in Brazil. Whole-genome analysis revealed that the E. coli isolate belonged to the widespread sequence type (ST) 101 and harbored the mcr-1 gene on an IncX4 plasmid that was highly similar to mcr-1 -bearing IncX4 plasmids that were recently identified in Enterobacteriaceae from food, animal, and human samples recovered on different continents. These results suggest that self-transmissible IncX4-type plasmids may represent promiscuous plasmids contributing to the intercontinental spread of the mcr-1 gene.

Colorectal carcinoma is considered the fourth leading cause of cancer deaths worldwide. Several microorganisms have been associated with carcinogenesis, including Enterococcus spp., Helicobacter pylori, enterotoxigenic Bacteroides fragilis, pathogenic E. coli strains and oral Fusobacterium. Here we qualitatively and quantitatively evaluated the presence of oral and intestinal microorganisms in the fecal microbiota of colorectal cancer patients and healthy controls. Seventeen patients (between 49 and 70 years-old) visiting the Cancer Institute of the Sao Paulo State were selected, 7 of whom were diagnosed with colorectal carcinoma. Bacterial detection was performed by qRT-PCR. Although all of the tested bacteria were detected in the majority of the fecal samples, quantitative differences between the Cancer Group and healthy controls were detected only for F. nucleatum and C. difficile. The three tested oral microorganisms were frequently observed, suggesting a need for furthers studies into a potential role for these bacteria during colorectal carcinoma pathogenesis. Despite the small number of patients included in this study, we were able to detect significantly more F. nucleatum and C. difficile in the Cancer Group patients compared to healthy controls, suggesting a possible role of these bacteria in colon carcinogenesis. This finding should be considered when screening for colorectal cancer.