Biology subjects

Fluit, A. C.

Publications and source records attributed to Fluit, A. C..

3 recordsLinked to original sources

bioRxiv2022

Clostridioides difficile PCR ribotype 151 is polyphyletic and includes pathogenic isolates from cryptic clade C-II with mono-toxin pathogenicity loci that can escape routine diagnostics

We report a patient case with pseudomembranous colitis associated with a mono-toxin producing Clostridioides difficile belonging to the very rarely diagnosed PCR ribotype (RT) 151. The infection was difficult to diagnose, since the isolate and the feces sample tested negative for toxin-encoding genes using a routine commercial test. This prompted us to sequence n = 11 RT151s from various geographical regions to study their genomic characteristics and relatedness. By including whole genome sequence data from other sources, we could further place these isolates into the phylogenetic tree of C. difficile and assign them to their respective clades. These analyses revealed that 1) RT151s are polyphyletic with isolates falling into clades 1, and cryptic clades C-I and C-II 2) RT151 contains both non-toxigenic and toxigenic isolates and 3) RT151 C-II isolates contained mono-toxin pathogenicity loci (PaLoc). Additional analysis with PacBio circular consensus sequencing revealed that the isolate from our patient case report contains a novel PaLoc insertion site, lacked tcdA and a had significantly divergent tcdB sequence that might explain the failure of the diagnostic test. The study is noteworthy as 1) RT151 encompasses both typical and cryptic clades and 2) conclusive evidence for CDI due to clade C-II isolates was hitherto lacking.

microbiology↗

bioRxiv2021

Human monoclonal antibodies against Staphylococcus aureus surface antigens recognize in vitro biofilm and in vivo implant infections

Implant-associated Staphylococcus aureus infections are difficult to treat because of biofilm formation. Bacteria in a biofilm are often insensitive to antibiotics and host immunity. Monoclonal antibodies (mAbs) could provide an alternative approach to improve the diagnosis and/or treatment of biofilm-related infections. Here we show that mAbs targeting common surface components of S. aureus can recognize clinically relevant biofilm types. We identify two groups of antibodies: one group that uniquely binds S. aureus in biofilm state and one that recognizes S. aureus in both biofilm and planktonic state. In a mouse model, we show that mAb 4497 (recognizing wall teichoic acid (WTA)) specifically localizes to biofilm-infected implants. In conclusion, we demonstrate the capacity of several human mAbs to detect S. aureus biofilms in vitro and in vivo. This is an important first step to develop mAbs for imaging or treating S. aureus biofilms.

microbiology↗

bioRxiv2018

Bariatric surgery changes gut microbiota composition independent of operation type

BackgroundBariatric surgery in patients with morbid obesity, either through gastric sleeve gastrectomy or Roux-Y gastric bypass surgery, leads to sustainable weight loss, improvement of metabolic disorders and changes in the intestinal microbiota. Yet, the relationship between changes in gut microbiota, weight loss and the surgical procedure remains incompletely understood.\n\nSubjects/MethodsWe determined temporal changes in microbiota composition in 45 obese patients undergoing a crash diet followed by gastric sleeve gastrectomy (n= 22) or Roux-Y gastric bypass (n= 23). Intestinal microbiota composition was determined before intervention (baseline, S1), 2 weeks after a crash diet (S2), and 1 week (S3), 3 months (S4) and 6 months (S5) after surgery.\n\nResultsRelative to S1, the microbial diversity index declined at S2 and S3 (p< 0.05), and gradually returned to baseline levels at S5. The crash diet was associated with an increased abundance of Rikenellaceae and decreased abundances of Ruminococcaceae and Streptococcaceae (p< 0.05). After surgery, at S3, the relative abundance of Bifidobacteriaceae had decreased (compared to the moment directly after the crash diet), whereas those of Streptococcaceae and Enterobacteriaceae had increased (p< 0.05). Increased weight loss during the next 6 months was not associated without major changes in microbiota composition. Significant differences between both surgical procedures were not observed at any of the time points.\n\nConclusionsIn conclusion, undergoing a crash diet and bariatric surgery were associated with an immediate but temporary decline in the microbial diversity, with immediate and permanent changes in microbiota composition, with no differences between patients undergoing gastric sleeve gastrectomy or Roux-Y gastric bypass surgery.

microbiology↗