A. butzleri infections report diarrhea associated with Arcobacter abdominal pain; nausea and vomiting or fever also occur (10,11). A third species, A. skirrowii, has recently been iso- Species in lated from a person with chronic diarrhea (12). Despite 1 these occasional reports, the contribution of Arcobacter Humans species to human diarrhea is still unknown. The aim of our study was to compare the prevalence and the clinical fea- Olivier Vandenberg,*† Anne Dediste,* tures of A. butzleri isolated from stools with those of Kurt Houf,‡ Sandra Ibekwem,§ C. jejuni. Hichem Souayah,* Sammy Cadranel,¶ Nicole Douat,#** G. Zissis,* J.-P. Butzler,§ The Study and P. Vandamme‡ From January 1995 to December 2002, all stool sam- During an 8-year study period, Arcobacter butzleri was ples submitted to two hospital laboratories serving the the fourth most common Campylobacter-like organism iso- Brugmann, Queen Fabiola, and Saint-Pierre University lated from 67,599 stool specimens. Our observations sug- Hospitals in Brussels, Belgium, were examined macro- gest that A. butzleri displays microbiologic and clinical scopically for consistency, gross blood, and mucus and features similar to those of Campylobacter jejuni; however, microscopically for parasites, leukocytes, and erythro- A. butzleri is more frequently associated with a persistent, cytes. These samples were also cultured for common bac- watery diarrhea. terial pathogens. Stool samples of patients <2 years of age were also evaluated for rotavirus and enteric adenovirus ampylobacter is the most common cause of acute bac- since viral diarrhea is mainly seen in young children. Cterial enteritis in the United States and many other A specific culture protocol for the recovery of industrialized countries (1,2). When the diagnosis of infec- Campylobacter spp. and related organisms consisting of tion is based exclusively on culturing on selective media, one solid selective medium and a filtration method was >95% of Campylobacter infections are caused by systematically applied. In the selective agar method, the Campylobacter jejuni or C. coli. However, with refine- fecal suspension (approximately 1 g/mL of saline) was ments in isolation and identification methods, other related plated onto Butzler’s medium comprising Mueller-Hinton species such as C. upsaliensis, C. jejuni subsp. doylei, C. agar (Oxoid Ltd, Basingstoke, United Kingdom) contain- fetus subsp fetus, C. concisus, Arcobacter butzleri, ing 5% sheep blood and the antimicrobial supplement cef- Helicobacter fennelliae, and H. cinaedi, have emerged as operazone 30 mg/L, rifampicin 10 mg/L, and amphotericin potential enteric human pathogens (3). Since most labora- B 2 mg/L (Institute Virion, Rüschlikon, Switzerland) (13). tories do not use appropriate culture conditions to detect all The plates were incubated for 48 h at 42°C in a microaer- Campylobacter spp. and related organisms or do not iden- obic atmosphere (5% O2, 6% H2, 10% CO2, and 79% N2). tify isolates to species level, data on the incidence and clin- The plates were examined daily for growth of ical importance of these non–C. jejuni/coli organisms are Campylobacter species. scarce. The membrane filtration method was performed During the past decade, improvements in isolation tech- according to Lopez (14). Stool samples were diluted 1:5 in niques in veterinary medicine have led to the discovery of Brucella broth. Cellulose acetate filters (50 mm in diame- Arcobacter spp. as animal pathogens. Members of the ter) with a pore size of 0.45 µm were placed on the surface genus Arcobacter are aerotolerant Campylobacter-like of Mueller-Hinton agar plates containing 5% sheep blood. organisms. They were first isolated from aborted bovine Eight drops of the fecal suspension were placed on the top fetuses by Ellis in 1977 (4). Arcobacter spp. differ from of the membrane and allowed to filter passively for 30 min Campylobacter spp. by their ability to grow at lower tem- at 37°C in air. After filtration, the filters were removed, peratures and in air (5). Later, Arcobacter infections in and the plates were incubated at 37°C in a microaerobic humans were also described. Two species, A. butzleri and, atmosphere for up to 10 days. more rarely, A. cryaerophilus, have been associated with Two specific procedures for isolating Arcobacter were enteritis and occasionally bacteremia (6–9). Patients with used successively. Until April 1995, we used a membrane filtration technique (15). Subsequently, we switched to *Saint-Pierre University Hospital, Brussels, Belgium; †Free University of Brussels, Brussels, Belgium; ‡Ghent University, 1Presented in part at the 11th International Congress on Infectious Ghent, Belgium; §Vrije Universiteit Brussel, Brussels, Belgium; Diseases, Cancun, Mexico, Mar 4–8, 2004. (Abstract P09.030); ¶Queen Fabiola University Hospital, Brussels, Belgium; and at the 12th International Workshop on Campylobacter, #Brugmann University Hospital, Brussels, Belgium; and **Queen Helicobacter and Related Organisms. Aarhus, Denmark, Sept Fabiola University Hospital, Brussels, Belgium 6–10, 2003 (Abstract K-07). Emerging Infectious Diseases • www.cdc.gov/eid • Vol. 10, No. 10, October 2004 1863 DISPATCHES direct plating on Arcobacter selective medium (16), for and patients from a foreign country referred for surgery), which 0.5 g of stool samples was injected into an enrich- and underlying disease. Diarrhea was defined as at least ment broth (Brucella broth + antimicrobial supplement three unformed or liquid stools per day for at least 3 days. consisting of piperacillin 75 mg/L, cefoperazone 25 mg/L, Because of the study’s retrospective nature, we could only amphotericin B 10 mg/L, trimethoprim 20 mg/L, and classify diarrhea as acute (duration <15 days) or chronic cycloheximide 100 mg/L + 5% laked horse blood) and (duration >15 days). Treatment history included antimicro- incubated for 24 h at 25°C in a microaerobic atmosphere. bial history and use of intravenous fluid therapy, and, final- After incubation, 40 µL of enriched broth was plated onto ly, clinical status after 1 month of treatment (cure or Arcobacter selective medium (16). The plates were then persistent diarrhea). incubated for 3 days at 25°C in a microaerobic atmosphere All parameters were compared between index patients and examined daily. and matched controls. Comparisons were made by Pearson Gram-negative, motile, spiral, or curved rods were iden- χ2 test for 1:3 control data. Odds ratios (OR) and 95% con- tified as Campylobacter by morphologic and biochemical fidence intervals (CI) were calculated. characteristics consistent with the genus Campylobacter, as From January 1995 to December 2002, a total of 67,599 recommended by Vandamme et al. (5). A complementary stool specimens from 40,995 patients were submitted for distinction between A. butzleri and A. cryaerophilus was bacteriologic stool culture. These cultures yielded achieved by using sodium dodecyl sulfate–polyacrylamide Campylobacter and related organisms in 1,906 patients, gel electrophoresis of whole-cell proteins and by a multi- Salmonella species in 1,720 patients, and Shigella species plex polymerase chain reaction assay (17). in 244 patients. Other identified pathogens include To assess the pattern of clinical disease, patients with A. enteropathogenic Escherichia coli (137 patients), Yersinia butzleri infection were matched against three randomly enterocolitica (87 patients), Plesiomonas spp. (22 selected control patients with C. jejuni infection. To patients), and Aeromonas spp. (21 patients). achieve this, all charts of patients with A. butzleri infection Among the 1,906 Campylobacter and related organ- and controls were reviewed retrospectively by combining isms isolated during the study period, 77.2% were C. jeju- the records of the medical and microbiology departments. ni, 11.4% were C. coli, and 4.5% were C. upsaliensis A structured, close-ended questionnaire was used to collect (Table 1). Ninety-seven Arcobacter isolates were obtained the patient’s history, age, sex, status (outpatient or hospi- from 77 patients. Among them, A. butzleri was the most talized for >48 h) and history of international travel. The frequently isolated species (84 isolates from 67 patients), clinical history included diarrhea within the preceding 3 accounting for 3.5 % of the Campylobacter and related months, duration of symptoms, nature of the diarrhea organisms bacterial group. Thirteen A. cryaerophilus iso- (watery or bloody and presence of cells), intensity of fever, lates from 10 patients were obtained, but no A. skirrowii nausea or vomiting, abdominal pains, asymptomatic car- isolates were found. Other species, such as C. concisus, C. riage (routine screening of enteric pathogens in stools of fetus, C. curvus, C. lari, and C. hyointestinalis, were also HIV-infected persons, other immunocompromised states, found in small numbers (Table 1). 1864 Emerging Infectious Diseases • www.cdc.gov/eid • Vol. 10, No. 10, October 2004 Arcobacter Species in Humans Medical records were available for 61 of the 67 patients Rectal bleeding, inflammatory exudates, or both were with A. butzleri infection. Ages of patients with A. butzleri significantly less common in A. butzleri than in C. jejuni infection were 30 days–90 years; there were slightly more infection (OR 0.15, 95% CI 0.05–0.46). A concomitant female than male patients. Fourteen patients were hospital- infection with another enteric pathogen occurred in a high- ized for >48 h. Four patients had traveled abroad before er