Prevalence of enterotoxin producing Staphylococcus aureus in stools of patients with nosocomial diarrhea.
BACKGROUND
Nosocomial diarrhea causes prolonged hospital stay leading to additional diagnostic and therapeutic procedures resulting in higher costs. A total of 20%-25% of antibiotic-associated diarrhea (AAD) cases are attributed to Clostridium difficile. Other microorganisms like Clostridium perfringens and Staphylococcus aureus are discussed to be associated with AAD.


METHODS
This study evaluated the prevalence of enterotoxigenic S. aureus in stool samples submitted to the laboratory with the diagnosis nosocomial diarrhea. A total of 2,727 stools from clinical patients were investigated for S. aureus and C. difficile. Samples were cultured for both bacteria and a C. difficile toxin A and B assay was performed from all stools. Isolated S. aureus were investigated for enterotoxin production and for resistance against methicillin. In addition, both assays were evaluated for determination of S. aureus enterotoxins directly in stool samples.


RESULTS
Out of 2,727 stools investigated, 198 grew S. aureus and 148 C. difficile. Toxins A/B from C. difficile were detected in 184 stools. A total of 114 S. aureus strains produced the following enterotoxins in vitro: A, 36; B, 20; C, 19; D, 68; E, 2. Both pathogens were found in 25 stools. Twenty-nine (14.6%) S. aureus strains were identified as methicillin-resistant. The two toxin assays evaluated in this study were not able to detect S. aureus enterotoxins directly in stools.


CONCLUSIONS
The role of enterotoxigenic S. aureus in the pathogenesis of nosocomial and AAD needs further consideration. It might be necessary to investigate stool samples from patients with AAD/nosocomial diarrhea for S. aureus on a routine basis.
Flemming
K
K
Institute for Medical Microbiology and Epidemiology of Infectious Diseases, University of Leipzig, 04103, Leipzig, Germany.
Ackermann
G
G
D001426:Bacterial Proteins / Q000096:biosynthesis; D001427:Bacterial Toxins / Q000032:analysis; D016360:Clostridioides difficile / Q000302:isolation & purification / Q000378:metabolism; D003428:Cross Infection / Q000453:epidemiology / Q000382:microbiology*; D003967:Diarrhea / Q000382:microbiology*; D004768:Enterotoxins / Q000032:analysis / Q000096:biosynthesis*; D005243:Feces / Q000737:chemistry / Q000382:microbiology*; D006801:Humans; D016106:Methicillin Resistance; D008826:Microbial Sensitivity Tests; D015995:Prevalence; D013203:Staphylococcal Infections / Q000453:epidemiology / Q000382:microbiology*; D013211:Staphylococcus aureus / Q000302:isolation & purification / Q000378:metabolism*
D001426:Bacterial Proteins; D001427:Bacterial Toxins; C488583:Clostridium difficile lethal toxin B; D004768:Enterotoxins; C041348:tcdA protein, Clostridium difficile