Genomic Study on Blood Culture Isolates From Patients With Infection-associated Glomerulonephritis.

INTRODUCTION

infection-associated glomerulonephritis (SAGN), is an autoimmune sequela of infection affecting a subset of infected patients without specific predictive factors, frequently presenting with acute nephritic syndrome and propensity for chronic kidney disease. We performed a comparative genotypic and phenotypic analysis of isolates from patients that did and those that did not develop SAGN.

METHODS

We had 22 culture-proven cases of SAGN from Ohio State University Wexner Medical Center (OSUWMC) from 2004 to 2016, 9 of 22 being blood cultures, with archived isolates. These, along with blood culture isolates from 12 patients with no clinical evidence of SAGN (between ages 40 to 80 years) over the same period were used for genotyping. For host demographic comparison, we used all available SAGN cases ( = 85, including those with positive cultures other than blood; and patients with kidney biopsies received from referring hospitals) and all OSUWMC patients with positive cultures without glomerulonephritis (GN) ( = 23,496).

RESULTS

Multiple sequence types (STs) suggesting strain diversity was seen in the GN isolates with mainly clonal complexes (CC) 5 and 59. Mutations in the operon were identified in significantly higher number of the GN isolates (83%) than non-GN isolates (16%). Significant differences in β-hemolysis and biofilm formation was also observed between the groups.

CONCLUSION

The functionality of these mutants remains to be seen, but the presently known effects of reduced function, namely increased surface adhesins, biofilm formation, and persistent bacteremia could be important microbial factors predisposing to SAGN and testing for them early during infection could help to predict its development.