Evaluation of Routine Enteric Pathogens in Hospitalized Patients: A Canadian Perspective

Abstract

K GOUGH, M ALFA, G HARDING. Evaluation of routine enteric pathogens in hospitalized patients: A Canadian perspective. Can J Infect Dis 1996;7(3):197-202. Diarrhea is a frequently encountered problem in hospitalized patients. Since nosocomial spread of routine enteric pathogens such as Salmonella species, Shigella species, Campylobacter species and Escherichia coli O:157 H:7 seldom occurs, testing for these organisms in patients hospitalized for longer than three days has been questioned. The goal of this study was to determine the length of hospitalization preceding detection of routine enteric pathogens and Clostridium difficile cytotoxin, and to develop guidelines for enteric cultures from hospitalized patients. The enteric pathogens detected in 1991 were C difficile toxin B(+), 77%; Campylobacter species, 10%; Salmonella species, 9%; E coli O:157 H:7, 3%; and Shigella species, 1%. For 1992, these numbers were 86%, 9%, 3%, 2% and 0%, respectively. None of the routine enteric pathogens isolated in 1991 or 1992 was detected in patients after their second day of hospitalization. Routine cultures for enteric pathogens on hospitalized patients were eliminated in February 1993, and physician ordering practices were monitored. With the exception of one campylobacter isolate per year, all routine enteric pathogens isolated in 1993 and 1994 were detected by the second day of hospitalization. Compliance with the changed protocol was 76% measured over a four-month period in 1993 and 74% over the year 1994. Savings of $3,648.10 were associated with rejecting 191 'inappropriate' specimens in 1994. It was concluded that routine enteric cultures are unnecessary for patients hospitalized more than two days, and that appreciable financial savings can be achieved if revised protocols for processing stool cultures are instituted. However, when enteric protocol changes are in place compliance must be evaluated to ensure appropriate utilization. Key Words: Clostridium difficile, Diarrhea, Enteric pathogens, Length of hospitalization, Nosocomial infection, Stool processingÉvaluation des organismes pathogènes entériques habituels chez les patients hospitalisés : perspective canadienne RÉSUMÉ : La diarrhée est un problème fréquent chez les patients hospitalisés. Étant donné que la propagation nosocomiale des organismes pathogènes entériques comme Salmonella, Shigella, Campylobacter et Escherichia coli O157H:7 survient rarement, le dépistage de ces organismes pathogènes chez les patients hospitalisés pendant plus de trois jours a été remis en question. L'objectif de cette étude était de déterminer la durée du séjour hospitalier précédant un dépistage des organismes pathogènes entériques courants et de la cytotoxine de Clostridium difficile et de mettre au point des directives de cultures entériques chez les patients hospitalisés. Les organismes pathogènes entériques décelés en 1991 étaient la toxine B(+) de C. difficile 77 %; le genre Campylobacter 10 %, le genre Salmonella 9 %, E. coli O157H:7 voir page suivante

Low Yield of FilmArray GI Panel in Hospitalized Patients with Diarrhea: an Opportunity for Diagnostic Stewardship Intervention

“…This retrospective evaluation of FilmArray GI panel tests performed on hospitalized adult patients admitted for Ͼ72 h in an academic tertiary-care hospital demonstrates that there is low yield of new positive results (4.8% overall and 3.0% after exclusion of chronic norovirus shedders and potential false positives) in this hospitalized population, similar to published literature for conventional stool cultures and exams for protozoa (3)(4)(5)(6), even though the FilmArray GI panel detects additional pathogens not routinely detected by conventional methods. No significant difference in positivity rates between immunocompromised and immunocompetent patients was seen in this study, although it was underpowered for this comparison.…”

“…Due to the sensitivity of the assay, it has taken the place of conventional stool cultures and parasite exams for protozoa in some institutions. Historically, conventional stool microbiology tests are not performed after a patient has been admitted for more than 3 days, as multiple studies have shown that the yield in hospitalized patients is exceptionally low (Ͻ1.5%) (3)(4)(5)(6). Given that FilmArray GI panel tests for bacterial, viral, and protozoal pathogens not routinely detected by conventional microbiological assays, it is not known if this same standard should be applied to this test.…”

Stool submission data to help inform population-level incidence rates of enteric disease in a Canadian community

“…Of the 1·9%, 39% were isolated from patients aged 0–4 years, whereas only 20% of the Salmonella spp.-positive outpatient specimens were isolated in the same age group. It has been reported that the majority of enteric pathogens isolated from inpatients in a hospital represent patients who had been hospitalized for <2 days, suggesting the infection was a result of exposure to the pathogen prior to being admitted to the hospital [24]. The number of days hospitalized prior to submitting a stool sample was not collected in this study but would help inform our interpretation of exposure source, especially for inpatients aged 0–4 years, in future studies.…”

Differential Yield of Pathogens from Stool Testing of Nosocomial versus Community‐Acquired Paediatric Diarrhea

“…Because of the variety of organisms, it is difficult and expensive for clinical laboratories to do a complete etiological examination of diarrheal stool specimens. Some investigators, mostly studying adult populations, have recently questioned the appropriateness of performing a complete etiological examination on stool specimens for diarrheal diseases (13)(14)(15)(16)(17)(18). The few published reports on stool testing in the paediatric population have either not differentiated CAD from NAD (19)(20)(21), or have excluded viral testing or screening for ova and parasites (17)(18)(19)(20)(21).…”