No abstract

cHuman cytomegalovirus (CMV) has historically been the major infectious cause of morbidity and mortality among patients receiving hematopoietic cell or organ transplant. Standard care in a transplant setting involves frequent monitoring of CMV viral load over weeks to months to determine when antiviral treatment may be required. Quantitative PCR (qPCR) is the standard molecular diagnostic method for monitoring. Recently, digital PCR (dPCR) has shown promise in viral diagnostics, although current dPCR systems have lower throughput than qPCR systems. Here, we compare qPCR and droplet digital PCR (ddPCR) for CMV detection in patient plasma samples. Droplet digital PCR exhibits increased precision over qPCR at viral loads of >4 log 10 with equivalent sensitivity. However, retrospective analysis of longitudinal samples from transplant patients with CMV viral loads near therapeutic thresholds did not provide evidence that the improved precision of ddPCR would be of clinical benefit. Given the throughput advantages of current qPCR systems, a widespread switch to dPCR for CMV monitoring would appear premature.

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°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. P atients with acute gastroenteritis commonly present to emergency departments (EDs) and primary care facilities worldwide. Aetiological agents can be viral, bacterial, or protozoan; and bacterial agents can be either enteropathogenic, toxigenic, or both. The guidelines of the American College of Gastroenterology recommend that stool cultures in adults are indicated in the presence of severe diarrhoea, a temperature >38.5°C (orally), passage of bloody stools, or persistent diarrhoea.1 Most cases of acute infectious diarrhoea caused by bacterial enteric pathogens are self limiting. The main goals in management are symptomatic treatment, rehydration or prevention of dehydration, prevention of spread of infection, and empiric antibiotic treatment in selected cases.2 3 Most practitioners believe that by the time stool culture results are available, the impact on practical treatment of individual patients is most often minimal. However, to date, this has not been formally studied and quantified in indexed literature. Therefore, the aims of this stud...