Acute bacterial diarrhoea in the emergency room: therapeutic implications of stool culture results

Diagnostic yield of stool culture and probable predictive factors

BACKGROUND AND AIM

Stool analysis is commonly performed to diagnose certain gastrointestinal diseases. The diagnostic yield of stool culture,  a method of stool analysis, is variable worldwide and is unclear in the Kingdom of Saudi Arabia. This study was conducted to determine the diagnostic yield of stool culture from the year 2008 to 2020 and to determine the predictors for a positive stool culture. Furthermore, antibiotic susceptibility patterns of the detected copro-pathogens in the same time period were collected and studied.

METHODS

This is a retrospective case-control study in which patients' data was collected from the hospital's electronic health record. The results of all stool analyses performed from 2008 to 2020 and associated patients' characteristics were collected.  Characteristics of cases with a positive stool culture were compared to the characteristics of those without to identify the predictors for positive stool cultures.

RESULTS

Copro-pathogens were detected in 89.4% of cultured stool samples. Salmonella spp (1590/1775, 89.6%) was the most common organism followed by Shigella spp. (84/1775, 4.7%) and Campylobacter spp (45/1775, 2.5%). Male sex, the 1-5 age group, positive fecal occult blood test results, and positive stool leukocyte test results were associated with a positive stool culture result. Cultured copro-pathogens were highly sensitive to Trimethoprim/Sulfamethoxazole and Ampicillin.

CONCLUSIONS

Stool analysis was found to be a test of high diagnostic yield. However, there is still a need for more studies on this subject with a focus on possible predictive factors for specific organisms.

Microbial aetiology of acute diarrhoea in children under five years of age in Khartoum, Sudan

Diarrhoea is one of leading causes of morbidity and mortality worldwide. Recent estimations suggested the number of deaths is close to 2.5 million. This study examined the causative agents of diarrhoea in children under 5 years of age in suburban areas of Khartoum, Sudan. A total of 437 stool samples obtained from children with diarrhoea were examined by culture and PCR for bacteria, by microscopy and PCR for parasites and by immunoassay for detection of rotavirus A. Of the 437 samples analysed, 211 (48 %) tested positive for diarrhoeagenic Escherichia coli, 96 (22 %) for rotavirus A, 36 (8 %) for Shigella spp., 17 (4 %) for Salmonella spp., 8 (2 %) for Campylobacter spp., 47 (11 %) for Giardia intestinalis and 22 (5 %) for Entamoeba histolytica. All isolates of E. coli (211, 100 %) and Salmonella (17, 100 %), and 30 (83 %) isolates of Shigella were sensitive to chloramphenicol; 17 (100 %) isolates of Salmonella, 200 (94 %) isolates of E. coli and (78 %) 28 isolates of Shigella spp. were sensitive to gentamicin. In contrast, resistance to ampicillin was demonstrated in 100 (47 %) isolates of E. coli and 16 (44 %) isolates of Shigella spp. In conclusion, E. coli proved to be the main cause of diarrhoea in young children in this study, followed by rotavirus A and protozoa. Determination of diarrhoea aetiology and antibiotic susceptibility patterns of diarrhoeal pathogens and improved hygiene are important for clinical management and controlled strategic planning to reduce the burden of infection.

What Have We Learnt from Bacterial Stool Culture Results? a Retrospective Study of Hospitalised Gastroenteritis Cases in a Regional Hospital in Hong Kong

Background

Stool culture is one of the common investigations done for patients with gastroenteritis, and fluoroquinolones have been used frequently for suspected bacterial gastroenteritis.

Objective

To study the yield of bacterial pathogens in stool culture in a local regional hospital for in-patients with gastroenteritis and the individual pathogens identified. Also, the value of stool culture and the prescription of fluoroquinolones as empirical antibiotics were reviewed.

Methods

This was a retrospective study. All in-patients with the principal diagnosis of “gastroenteritis” in the year 2007 were reviewed. We excluded pregnant patients and patients under 18 years of age. Patients were divided into two age groups and data were analysed including demographics, clinical findings, admission time and culture results. Antibiotics prescription behaviour was also analysed.

Results

A total of 837 adult patients fulfilled the criteria. Among them, 562 cases had their stool saved and sent for bacterial culture. Eighty-nine cases were found to have their stool cultures positive for bacteria. The identified pathogens were namely Vibrio parahaemolyticus (38.2%), Salmonella species (34.8%), Campylobacter species (11.2%), Plesiomonas species (10.1%) and Aeromonas species (3.4%) respectively. The yield of positive stool culture was 15.8%.

Conclusion

Vibrio parahaemolyticus and Salmonella species were still the most common pathogens for bacterial gastroenteritis among hospitalized patients in Hong Kong, especially in the young and middle aged. Their occurrence followed a seasonal pattern. Physicians had a tendency to prescribe fluoroquinolones for cases with fever and travel history. Also, the problem of antibiotic resistance did exist. It is important for practitioners to follow local guidelines before ordering microbiological investigations on stool and prescribing empirical antibiotic treatment.

Acute bacterial gastroenteritis: a study of adult patients with positive stool cultures treated in the emergency department

OBJECTIVES

To investigate the presenting clinical features of acute bacterial gastroenteritis in adult patients treated as outpatients in the emergency department (ED), and the pathogens responsible in this setting and population; and to identify the frequency with which positive stool culture result changes management.

METHOD

This was a retrospective study of all patients who attended the accident and emergency department of an university affiliated hospital in Hong Kong over a 12 month period, who satisfied the following inclusion criteria: (a) age >/=16, (b) presented with acute gastroenteritis, (c) treated as outpatients with or without observation, and (d) had positive stool cultures.

RESULTS

One hundred and thirty patients were included. Pathogens identified were Vibrio parahaemolyticus (42.3%), Samonella spp (34.6%), Plesiomonas spp (9.2%), Campylobacter spp (6.9%), Aeromonas spp (6.9%), and Shigella spp (6.2%). Mean highest body temperature was 37.5 degrees C (95% confidence intervals (CI) 37.3 to 37.6). Bloody diarrhoea was present in 14 patients (10.8%). Mean duration of diarrhoea, from onset to the completion of stay in ED, was 2.2 days (95% CI 1.7 to 2.7). Likewise, mean duration of abdominal pain was 1.8 days (95% CI 1.5 to 2.1). Mean number of unformed stools per day was 9.3 (95% CI 8.3 to 10.3). Change of management, subsequent to the availability of positive stool culture results, was not required in 115 (88.5%) patients. Ciprofloxacin resistance occurred in eight (6.2%) cases, and seven of nine campylobacter isolates. Campylobacter positive patients had a significantly longer duration of abdominal pain (p=0.0236) and were less likely to be dehydrated (p=0.0103).

CONCLUSIONS

Most patients with bacterial gastroenteritis do not present with high fever, bloody diarrhoea, or persistent diarrhoea, but generally have quite severe diarrhoea. Stool cultures do not change management for most patients. Vibrio parahaemolyticus is the commonest bacterial pathogen identified.