Isolation of Campylobacter Species from Stool Samples by Use of a Filtration Method: Assessment from a United States-Based Population

Abstract

Fecal samples submitted to our clinical microbiology laboratory from patients in the Philadelphia region were prospectively analyzed for Campylobacter species other than C. jejuni and C. coli using a filtration method and microaerobic conditions with increased H 2 concentrations. Of 225 samples tested, 13 (5.8%) yielded Campylobacter species, with frequent isolation of C. concisus. The majority of Campylobacter species were not clinically significant. Additional studies in U.S. populations are warranted.KEYWORDS Campylobacter jejuni, campylobacter, campylobacteriosis, culture methods, gastrointestinal infection C ampylobacter species other than C. jejuni and C. coli, such as C. concisus, C. upsaliensis, C. ureolyticus, C. sputorum, and others, are not isolated commonly from routine stool cultures due to the nonthermophilic nature of the species and/or inhibition by antimicrobial agents in commonly used selective medium (1). Except for C. upsaliensis, these species may not be detected in recently developed molecular multiplex stool pathogen test kits. Little is known about the occurrence of these species in U.S. patients. While species such as C. upsaliensis are known pathogens (2), the pathogenicity of many other species, such as C. concisus, is controversial (3). Recovery of Campylobacter spp. from stool cultures requires the addition of a filtration method and sufficient H 2 in the microaerobic environment (1). The purpose of this study was to determine the frequency and clinical relevance of Campylobacter species from stool cultures in a United States-based clinical laboratory. RESULTS AND DISCUSSIONWe processed 225 fecal samples submitted to the Hospital of the University of Pennsylvania (HUP) Clinical Microbiology Laboratory for routine testing for gastrointestinal pathogens from September to December 2016 for the presence of Campylobacter spp. using the filtration method. Campylobacter spp., including C. jejuni, C. coli, C. lari (n ϭ 10), and other species (n ϭ 13), were recovered from 23 samples processed by this method. All of the samples from which C. jejuni, C. coli, or C. lari isolates were recovered using the filtration method were also positive in the Verigene enteric panel multiplex molecular assay (Table 1). Of the 13 isolates other than C. jejuni, C. coli, and C. lari, 4 were recovered using 0.45-m nitrocellulose filters (30.7%), 8 (61.5%) were recovered on 0.65-m nitrocellulose filters, and 13 (100%) were recovered from 0.6-m polycarbonate filters, suggesting the superiority of polycarbonate filters for recovery of Campylobacter spp. (Fig. 1). These results are consistent with those reported by Nielsen et al. (4), who also found that polycarbonate filters were superior to cellulose acetate filters for recovery of C. concisus from stool samples.

Detection of Campylobacter jejuni and Campylobacter coli by a PCR assay in Patients with Diarrhea

“…The current study agreed with the previous study done in the USA despite the environmental difference between Iraq and the USA as well as poor living conditions, which isolated Campylobacter (5.8%) (17) . Also, the previous study was carried out in south India to Detection and species identification of Campylobacter in stool samples by Rajendran et al they indicate that 4.5% Campylobacter (18) .…”

Identification and Characterization of Campylobacter Species in Livestock, Humans, and Water in Livestock Owning Households of Peri-urban Addis Ababa, Ethiopia: A One Health Approach

“…The majority of previous studies in Ethiopia used only the culture and biochemical test approach for the isolation and identification of Campylobacter. This latter approach has the potential to be less sensitive and specific, and could be a reason for the observed differences in prevalence (51)(52)(53). Nevertheless, the higher prevalence of zoonotic thermophilic Campylobacter species observed in livestock in our study is of considerable concern, as poultry and other livestock species move freely around the household, contaminating the environment, and are a source of infection for humans, especially children.…”

Campylobacter culture fails to correctly detect Campylobacter in 30% of positive patient stool specimens compared to non-cultural methods

“…Such false-negative results can mean that the patient may continue to receive ineffective antibiotic treatment (e.g., if bacteria are fluoroquinolone resistant) [ 21 ]. False-positive results from conventional culture on plates containing antibiotics, when a candidate colony among fecal flora is not actually C. jejuni or C. coli , have also been reported and led to the development of multiple methods to optimize accurate recognition of colonies [ 27 , 28 ]. Although uncommon, such false-positive results can encourage continued potentially unsafe antibiotic treatment and, more importantly, cut short the search for the causative pathogen.…”