- Cristina Rodriguez+
- Bernard Taminiau†,
- Nicolas Korsak,
- Véronique Avesani,
- Johan Van Broeck,
- Philippe Brach,
- Michel Delmée and
- Georges Daube
The Author(s). 2016m,Received: 13 April 2016,Accepted: 23 September 2016
Published: 1 October 2016
Increasing age, several co-morbidities, environmental contamination, antibiotic exposure and other intestinal perturbations appear to be the greatest risk factors for C. difficile infection (CDI). Therefore, elderly care home residents are considered particularly vulnerable to the infection. The main objective of this study was to evaluate and follow the prevalence of C. difficile in 23 elderly care home residents weekly during a 4-month period. A C. difficile microbiological detection scheme was performed along with an overall microbial biodiversity study of the faeces content by 16S rRNA gene analysis.
Seven out of 23 (30.4 %) residents were (at least one week) positive for C. difficile. C. difficile was detected in 14 out of 30 diarrhoeal samples (43.7 %). The most common PCR-ribotype identified was 027. MLVA showed that there was a clonal dissemination of C. difficile strains within the nursing home residents. 16S-profiling analyses revealed that each resident has his own bacterial imprint, which was stable during the entire study. Significant changes were observed in C. difficile positive individuals in the relative abundance of a few bacterial populations, including Lachnospiraceae and Verrucomicrobiaceae. A decrease of Akkermansia in positive subjects to the bacterium was repeatedly found.
A high C. difficile colonisation in nursing home residents was found, with a predominance of the hypervirulent PCR-ribotype 027. Positive C. difficile status is not associated with microbiota richness or biodiversity reduction in this study. The link between Akkermansia, gut inflammation and C. difficile colonisation merits further investigations.
C. difficile Elderly care home residents 16S rRNA gene analysis
Clostridium difficile is a Gram-positive, anaerobic, spore-forming, rod-shaped bacterium that has been widely described in the intestinal tract of humans and animals. In 1978, C. difficile was recognized as a major cause of antibiotic associated diarrhoea and, in the most serious cases pseudomembranous colitis [1, 2, 3]. Since then, many outbreaks have been reported; most of them were associated with the emergence of a specific subtype, hyper-virulent PCR-ribotype 027 . Nowadays, C. difficile is a worldwide public health concern as it is considered the major cause of antibiotic-associated infections in healthcare settings . A recent report of C. difficile infection (CDI) cost-of-illness attributes a mean cost ranging from 8,911 to 30,049 USD for hospitalised patients (per patient/admission/episode/infection) in the USA  and annual economic burden estimated around 3,000 million euro in Europe .
CDI is more commonly diagnosed among older people in nursing homes. High isolation frequencies have been described in USA, with up to 46 % of elderly residents testing positive for C. difficile, while in Europe or Canada the reported rates are much lower, varying between 0.8 and 10 % . This is partly because elderly people are more commonly in hospitals, have an antibiotic treatment and age-related changes in intestinal flora and host defences, as well as the presence or other underlying health problem [8, 9, 10]. These factors can have an impact on the intestinal microbiota, which may promote C. difficile colonisation and the development of the infection . Therefore, a new concern of several studies has been the identification of the microbial communities implicated in the CDI through the use of new sequencing techniques, like metagenomics .
The aim of this study was to evaluate and follow the prevalence of C. difficile among the residents of a Belgian nursing home. Multilocus variable number of tandem repeats analysis (MLVA) was performed to determine the genetic diversity of the C. difficile isolates and possible cross-infection between patients. Additionally, 16S rRNA gene sequencing was used to characterise the faecal microbiota of the elderly residents, to evaluate the global evolutions of the total microbiota and to identify possible relationships between certain bacteria populations and C. difficile colonisation, diarrhoea and antibiotic treatment.