Pseudo-outbreak of Klebsiella oxytoca spontaneous bacterial peritonitis attributed to contamination of multidose vials of culture medium supplement.
OBJECTIVE
To determine the source of a cluster of Klebsiella oxytoca isolates cultured from peritoneal fluid of 3 patients with cirrhosis on a single day.


METHODS
Outbreak investigation and before-after study.


METHODS
A Veterans Affairs medical center.


METHODS
Epidemiologic investigation, analysis of antimicrobial susceptibility testing results and molecular typing of K. oxytoca isolates with repetitive sequence-based polymerase chain reaction (rep-PCR), review of microbiology laboratory procedures for processing peritoneal fluid cultures, and comparison of peritoneal fluid contamination rates 18 months before and after modification of laboratory procedures for culturing peritoneal fluid.


RESULTS
Each of the peritoneal fluid samples that grew K. oxytoca was inoculated into blood culture bottles by different clinicians at different hospital locations. None of the patients had clinical findings suggestive of peritonitis or elevated polymorphonuclear cell counts in peritoneal fluid (range, 3-25 cells/μL). Molecular typing with rep-PCR demonstrated that the K. oxytoca isolates were genetically related (greater than 95% similarity). Laboratory procedures included the routine addition of a culture medium supplement of yeast extract and dextrose from a multidose vial into blood culture bottles with peritoneal fluid. After discontinuing use of the culture medium supplement, there was a marked reduction in the number of peritoneal fluid cultures deemed as contaminants (14.3% vs 0.9%; [Formula: see text]).


CONCLUSIONS
A pseudo-outbreak of K. oxytoca peritonitis and high rates of contamination of peritoneal fluid were attributable to contamination of a multidose culture medium supplement. This article highlights the importance of discouraging the use of multidose vials in all clinical settings.
Research Service, Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, Ohio.
Federico
F
Perez
Abhishek
A
Deshpande
Sirisha
S
Kundrapu
Andrea M
AM
Hujer
Robert A
RA
Bonomo
Curtis J
CJ
Donskey
D000328:Adult; D001202:Ascitic Fluid / Q000382:microbiology; D003428:Cross Infection / Q000209:etiology* / Q000382:microbiology; D003470:Culture Media; D004196:Disease Outbreaks; D004866:Equipment Contamination; D005189:False Positive Reactions; D006801:Humans; D007710:Klebsiella Infections / Q000209:etiology* / Q000382:microbiology; D041121:Klebsiella oxytoca / Q000302:isolation & purification; D008297:Male; D008875:Middle Aged; D009820:Ohio / Q000453:epidemiology; D010538:Peritonitis / Q000209:etiology* / Q000382:microbiology
D003470:Culture Media