New Methods for Detection of Campylobacters in Stool Samples in Comparison to Culture

Abstract

Campylobacter species, especially Campylobacter jejuni and Campylobacter coli, are a major cause of human bacterial enteritis. Current detection in stools is done essentially by culture on selective and nonselective media with filtration. These methods were compared to 2 molecular biology methods, an in-house real-time PCR and a multiplex PCR named Seeplex Diarrhea ACE Detection, and 3 immunoenzymatic methods, Premier Campy, RidaScreen Campylobacter, and ImmunoCard Stat!Campy. Out of 242 stool specimens tested, 23 (9.5%) fulfilled the positivity criteria, i.e., they were positive by one or both culture methods or, in case of a negative culture, by a positive molecular method and a positive immunoenzymatic method. The striking feature of this study is the low sensitivity of culture, in the range of 60%, in contrast to immunoenzymatic and molecular tests.The incidence of Campylobacter-associated food poisoning has gradually increased, and the organism is now considered to be the leading cause of bacterial gastroenteritis worldwide (4). These infections can also lead to extraintestinal diseases and severe long-term complications (9). Campylobacter jejuni and Campylobacter coli are the most frequently isolated species in this context and in our experience account for 80% and 16%, respectively, of all the isolates received in our laboratory every year (2a). Campylobacter species are bacteria with a special culture requirement, i.e., a microaerobic environment. During stool processing, the bacteria may have long contact with a normal atmosphere, and in addition, the progressive decrease in oxygen tension when gas-generating kits are used may not favor adequate growth. Furthermore, selective media are commonly used, and the antibiotics incorporated may inhibit certain Campylobacter strains. Anecdotal data have shown that spiral or curved bacteria are sometimes observed on stool smears while Campylobacter growth does not occur. In a recent study, DNA sequences of the Campylobacter genome were detected by a metagenomic analysis, while the standard culture methods were negative (5). In a pilot study using real-time PCR as a diagnostic tool, we also detected more campylobacters than with culture, but without being able to confirm that true positives were detected, since, at that time, we did not use multiple detection methods to establish positivity when culture was negative. Some immunoenzymatic tests have already been commercialized for several years, such as the ProSpecT Campylobacter Microplate Assay (Remel) (8) and the RidaScreen Campylobacter (R-Biopharm, Darmstadt, Germany) evaluated in our study. In this study, we took advantage of the availability of several kits to compare Campylobacter detection by molecular methods (2 PCRs) and by 3 immunoenzymatic methods to the standard culture methods. MATERIALS AND METHODS Materials.From 15 June to 30 October 2009, every stool specimen obtained from a symptomatic patient, i.e., a patient with a gastrointestinal illness, who was hospitalized for less than 48 h at Pellegrin H...

Detection of Campylobacter species in stool specimens from patients with symptoms of acute flaccid paralysis in South Africa

“…Campylobacter is a fastidious organism that is difficult to culture even from fresh stool samples [32][33]. It is well documented that in studies where qPCR was used as a diagnostic tool, more Campylobacter species were detected than with culture methods [33].The most common detected species of Campylobacter was C. jejuni (77.4%), an organism associated with GBS [4,10,14,15]. C. coli was less frequently detected (19.4%), and mixed infections of C. jejuni and C. coli were rare (3.2%).…”

Accurate detection ofCampylobacterspp. antigens by immunochromatography and enzyme immunoassay in routine microbiological laboratory

“…Furthermore, our data for the ICA also are comparable to those published for a different ICA, the immunoCard STAT! Assay [7,10,11]. Like the ICA evaluated by us, the immunoCard STAT!…”

“…Although confi rmation by PCR would have been desirable but unfortunately not feasible, some ICA-positive but culture-negative samples in our study might have been true positives as previously shown for both the immunoCard STAT! and the RidaQuick assay [7,9], although also false-positive results have been reported for both assays [9,13,14]. The new generation of the EIA tested has been improved compared with the previous type, which only had a sensitivity of 69% and a specifi city of 87% compared with culture [6].…”

“…Since cultural isolation of Campylobacter spp. may yield a considerable rate of falsenegative results [2,7] and PCR could not be performed in the present study, we calculated the positive and negative percent agreement (PPA and NPA, respectively) with 95% confi dence interval (95% CI) between the assays and culture.…”

Public health impacts of culture independent diagnostic testing in Australia

“…For example, Salmonella is easy to grow in culture, so concurrent or reflex culture will result in an isolate for further characterisation most of the time. In contrast, as Campylobacter is fastidious 8 , culture has a much lower sensitivity than PCR, resulting in a higher proportion of specimens positive only by PCR even when culture is attempted.…”