Role of Klebsiella Oxytoca in non-hemorrhagic antibiotic-associated diarrhea

Introduction: Recently, Klebsiella oxytoca was found to be the causative for antibioticassociated hemorrhagic colitis (AAHC). Whether K. oxytoca plays a role in non-hemorrhagic antibiotic-associated diarrhea (AAD) is unknown. The aim of our study was therefore to investigate whether this bacterium is associated with AAD.

Methods: 371 patients were recruited into 4 study groups: (1) group AAD (patients receiving antibiotics and experiencing diarrhea, n=107), (2) group A+D- (patients receiving antibiotics but not experiencing diarrhea, n=93), (3) group A-D+ (patients experiencing acute onset diarrhea but not receiving antibiotics, n=60), (4) group A-D- (control patients, n=111). Stool samples were plated on MacConkey agar and K. oxytoca was identified by API 20E. C. difficile was detected by toxin A/B antigen test. K. oxytoca strains were tested for cytotoxicity using a cell-culture assay.

Results: There was no significant difference in distribution of K. oxytoca in the 4 groups. 3 cases of AAHC were recorded. A total of 15 K. oxytoca strains were isolated during the study period in all patient groups. Five of these strains were found to be toxin – producing.

	AAD	A+D-	A-D-	A-D+
Number of patients	104	93	111	60
Positive for	1/104	1/93	5/111	5/60
K. oxytoca	(0,9%)	(1,1%)	(4,5%)	(8,3%)
Positive for	12/104	0/93	0/111	2/60
C. difficile toxin	(11,5%)	(0%)	(0%)	(33%)

Conclusion: In contrast to AAHC, K. oxytoca is not associated with non-hemorrhagic AAD.

Testing for K. oxytoca is therefore only warranted in patients with bloody diarrhea and a history suspicious of AAHC.