Performance of stool cultures before and after a 3-day hospitalization: fewer cultures, better for patients and for money

Diarrheal Morbidity During Hematopoietic Cell Transplantation: The Diagnostic Yield of Stool Cultures

INTRODUCTION

Diarrhea affects a significant proportion of patients undergoing hematopoietic cell transplantation (HCT). We explored the diagnostic yield of stool cultures for enteric pathogens among patients undergoing HCT.

METHODS

This is a single-center, retrospective study. Between 5/2007 and 4/2020, consecutive patients who underwent HCT were included if inpatient bacterial stool cultures were collected. Patient characteristics, results, and timing of stool cultures obtained during hospitalization were collected.

RESULTS

A total of 1072 individuals underwent autologous (n = 603) and allogeneic (n = 469) HCT. Overall, 947 stool culture samples were obtained from 561 (52%) patients with diarrheal illness during hospitalization for HCT. Most (99%) samples were obtained beyond 3 days of admission, mainly (77%) during neutropenia. Overall, only four (0.42%) (autologous, n = 3; allogeneic, n = 1) patients had a positive stool culture and in all cases Campylobacter spp. were the pathogens identified. The number of stool cultures needed-to-test to diagnose one case of bacterial infection was 237. The cost of diagnosing one case of bacterial diarrhea was US $8770. Patients with a positive stool culture did not have discerning characteristics.

CONCLUSIONS

In our experience, the yield of stool cultures for enteropathogens in patients undergoing HCT is extremely low and thus should be avoided in most cases.

Stool cultures at the ICU: get rid of it!

Background

Stool cultures for Campylobacter, Salmonella and Shigella and/or Yersinia spp. are frequently ordered in critically ill patients with diarrhea. The aim of this study is to analyze the diagnostic yield in a large cohort of critically ill patients. Therefore, we performed a cohort study at the Department of Intensive Care Medicine of a University Hospital (11 ICUs).

Results

From all patients who were admitted to the ICU between 2010 and 2015, stool cultures were taken from 2.189/36.477 (6%) patients due to diarrhea. Results of all stool cultures tested for Campylobacter, Salmonella and Shigella and/or Yersinia spp. were analyzed. Overall, 5.747 tests were performed; only six were positive (0.1%). In four of these, Campylobacter spp. were detected; diarrhea started within 48 h after ICU admission. Two patients with Salmonella spp. detection were chronic shedders. On the contrary, testing for Clostridium difficile via GDH- and toxin A/B-EIA yielded positive results in 179/2209 (8.1%) tests and revealed 144/2.189 (6.6%) patients with clinically relevant C. difficile infection.

Conclusions

Stool testing for enteric pathogens other than C. difficile should be avoided in ICU patients and is only reasonable when diarrhea commenced less than 48 h after hospital admission.

The yield of stool testing in hospital-onset diarrhea: Has evidence changed practice?

INTRODUCTION

Aside from examination for Clostridium difficile, the yield of stool testing in hospital-onset diarrhea is poor. Clinical practice guidelines discourage overzealous stool testing in patients with diarrhea that develops after the third hospital day. However, the adoption of this recommendation into clinical practice is limited. Furthermore, the effect of microbiology laboratory improvements on hospital-onset diarrhea testing is largely unknown.

METHODS

A retrospective cohort study was conducted in a university-affiliated community-hospital and included all adult inpatients who developed diarrhea after hospitalization.

RESULTS

132 adult patients (53% female) developed diarrhea after hospitalization in 2013. The cohort's mean age was 55.6 years. 46.2% of patients developed diarrhea in the first 3 days of hospitalization. Testing for parasites was negative in all examined 67 samples. Testing for C. difficile was positive in 13 cases (10.8%) out of 120 tested samples. Testing for other pathogens was positive in 1 sample (Campylobacter) out of 129 samples. Stool samples tested in the first 3 days of hospitalization were more likely to be positive (64.3 vs 35.7%, p = 0.1). Change in management was reported in 9 out of 14 patients (64.3%) with positive stool testing compared with 31 out of 118 patients (26.3%) with negative stool testing, p = 0.01.

CONCLUSION

Despite improvements in stool samples' testing, the yield continues to be low, especially in hospital-onset diarrhea past the third hospital day. Physicians' embracement of the '3-day rule' continues to be poor.

Update on molecular epidemiology of Shigella infection

PURPOSE OF REVIEW

Shigella spp. are important etiologic agents of diarrhea worldwide. This review summarizes the recent findings on the epidemiology, diagnosis, virulence genes, and pathobiology of Shigella infection.

RECENT FINDINGS

Shigella flexneri and Shigella sonnei have been identified as the main serogroups circulating in developing and developed countries, respectively. However, a shift in the dominant species from S. flexneri to S. sonnei has been observed in countries that have experienced recent improvements in socioeconomic conditions. Despite the increasing usage of molecular methods in the diagnosis and virulence characterization of Shigella strains, researchers have been unsuccessful in finding a specific target gene for this bacillus. New research has demonstrated the role of proteins whose expressions are temperature-regulated, as well as genes involved in the processes of adhesion, invasion, dissemination, and inflammation, aiding in the clarification of the complex pathobiology of shigellosis.

SUMMARY

Knowledge about the epidemiologic profile of circulating serogroups of Shigella and an understanding of its pathobiology as well as of the virulence genes is important for the development of preventive measures and interventions to reduce the worldwide spread of shigellosis.