Antibiotic-associated diarrhea due to Clostridium difficile (CDAD) is thought to reflect colonization of a disrupted microbial community by the pathogen. We profiled the fecal microbiota of patients with CDAD (both initial and recurrent episodes) by culture-independent phylogenetic analysis of 16S rRNA-encoding gene sequences. Compared with those from control subjects and patients with an initial episode, the fecal communities in patients with recurrent CDAD were highly variable in bacterial composition and were characterized by markedly decreased diversity. Preservation and restoration of the microbial diversity could represent novel strategies for prevention and treatment of recurrent CDAD, which is often recalcitrant to existing therapies.

BackgroundThe intestinal microbiome represents a complex network of microbes that are important for human health and preventing pathogen invasion. Studies that examine differences in intestinal microbial communities across individuals with and without enteric infections are useful for identifying microbes that support or impede intestinal health.Results16S rRNA gene sequencing was conducted on stool DNA from patients with enteric infections (n = 200) and 75 healthy family members to identify differences in intestinal community composition. Stools from 13 patients were also examined post-infection to better understand how intestinal communities recover. Patient communities had lower species richness, evenness, and diversity versus uninfected communities, while principle coordinate analysis demonstrated close clustering of uninfected communities, but not the patient communities, irrespective of age, gender, and race. Differences in community composition between patients and family members were mostly due to variation in the abundance of phyla Proteobacteria, Bacteroidetes, and Firmicutes. Patient communities had significantly more Proteobacteria representing genus Escherichia relative to uninfected communities, which were dominated by Bacteroides. Intestinal communities from patients with bloody diarrhea clustered together in the neighbor-joining phylogeny, while communities from 13 patients’ post-infection had a significant increase in Bacteroidetes and Firmicutes and clustered together with uninfected communities.ConclusionsThese data demonstrate that the intestinal communities in patients with enteric bacterial infections get altered in similar ways. Furthermore, preventing an increase in Escherichia abundance may be an important consideration for future prevention strategies.Electronic supplementary materialThe online version of this article (doi:10.1186/s40168-015-0109-2) contains supplementary material, which is available to authorized users.

University of Alabama at Birmingham and the Justin E. Rodgers Foundation.

BackgroundReports of the etiology of bacteremia in children from Nigeria are sparse and have been confounded by wide spread non-prescription antibiotic use and suboptimal laboratory culture techniques. We aimed to determine causative agents and underlying predisposing conditions of bacteremia in Nigerian children using data arising during the introduction of an automated blood culture system accessed by 7 hospitals and clinics in the Abuja area.MethodsBetween September 2008 and November 2009, we enrolled children with clinically suspected bacteremia at rural and urban clinical facilities in Abuja or within the Federal Capital Territory of Nigeria. Blood was cultured using an automated system with antibiotic removing device. We documented clinical features in all children and tested for prior antibiotic use in a random sample of sera from children from each site.Results969 children aged 2 months-5 years were evaluated. Mean age was 21 ± 15.2 months. All children were not systematically screened but there were 59 (6%) children with established diagnosis of sickle cell disease and 42 (4.3%) with HIV infection. Overall, 212 (20.7%) had a positive blood culture but in only 105 (10.8%) were these considered to be clinically significant. Three agents, Staphylococcus aureus (20.9%), Salmonella typhi (20.9%) and Acinetobacter (12.3%) accounted for over half of the positive cultures. Streptococcus pneumoniae and non-typhi Salmonellae each accounted for 7.6%. Although not the leading cause of bacteremia, Streptococcus pneumoniae was the single leading cause of all deaths that occurred during hospitalization and after hospital discharge.ConclusionS. typhi is a significant cause of vaccine-preventable morbidity while S. pneumoniae may be a leading cause of mortality in this setting. This observation contrasts with reports from most other African countries where non-typhi Salmonellae are predominant in young children. Expanded surveillance is required to confirm the preliminary observations from this pilot study to inform implementation of appropriate public health control measures.