Abstract
Clostridium difficile (CD) produces antibiotic associated diarrhea and leads to a broad range of diseases. The source of CD infection (CDI) acquisition and toxigenic profile are factors determining the impact of CD. This study aimed at detecting healthcare facility onset- (HCFO) and community-onset (CO) CDI and describing their toxigenic profiles in Bogotá, Colombia. A total of 217 fecal samples from patients suffering diarrhea were simultaneously submitted to two CDI detection strategies: (i) in vitro culture using selective chromogenic medium (SCM; chromID, bioMérieux), followed verification by colony screening (VCS), and (ii) molecular detection targeting constitutive genes, using two conventional PCR tests (conv.PCR) (conv.16S y conv.gdh) and a quantitative test (qPCR.16s). The CD toxigenic profile identified by any molecular test was described using 6 tests independently for describing PaLoc and CdtLoc organization. High overall CDI frequencies were found by both SCM (52.1%) and conv.PCR (45.6% for conv.16S and 42.4% for conv.gdh), compared to reductions of up to half the frequency by VCS (27.2%) or qPCR.16S (22.6%). Infection frequencies were higher for SCM and conv.16S regarding HCFO but greater for CO concerning conv.gdh, such differences being statistically significant. Heterogeneous toxigenic profiles were found, including amplification with lok1/3 primers simultaneously with other PaLoc markers (tcdA, tcdB or tcdC). These findings correspond the first report regarding the differential detection of CDI using in vitro culture and molecular detection tests in Colombia, the circulation of CD having heterogeneous toxigenic profiles and molecular arrays which could affect the impact of CDI epidemiology.
Highlights
Clostridium difficile (CD) has become one of the pathogens having the greatest worldwide clinical and economic impact during the last few years (Hung et al, 2015; Nanwa et al, 2015)
In silico analysis of the primer sets used for detecting CD infection (CDI) revealed that those targeting 16S.rRNA had 11 recognition sites in the C. difficile 630 reference strain sequence compared to the primer set targeting gdh which only had one recognition site
Aligning the 11 theoretical amplification products extracted from this strain’s sequence showed that the gene copies within the genome had one change in three of the eight copies giving 99.4% identity in both cases (156 bp amplification products for conv.16S and 155 quantitative PCR (qPCR).16S). This variable position was not located within conv.16S primer set annealing site; it was located within qPCR.16S reverse primer annealing site, related to the degenerate design in this position
Summary
Clostridium difficile (CD) has become one of the pathogens having the greatest worldwide clinical and economic impact during the last few years (Hung et al, 2015; Nanwa et al, 2015). Even though CDI’s greatest impact has been associated with HCFO, increased CDI community-onset (CO) has been observed (Chitnis et al, 2013), with incidence rates ranging from 1.3 to 2.7 per 10,000 patients-day (Evans and Safdar, 2015). Such scenarios have been reported in the USA, the UK and other developed countries, where integral CD prevention and control schemes have been brought into clinical practice (Balsells et al, 2016). Latin American CDI dynamics have mainly been studied in Chile, Uruguay, Costa Rica, Argentina and Mexico (Balassiano et al, 2012; Martin et al, 2016) and a 3.1 per 10,000 patients-day CDI incidence rate has been identified concerning HCFO (Lopardo et al, 2015); circulating strains’ CDI frequency and toxigenic profiles remain unknown for this region
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