A case of bacteremia caused by a rare Helicobacter species, Campylobacter-like organism 3 (CLO-3), in a 75-year-old man with prostate cancer and an indwelling urethral catheter for urinary retention, is reported. Oral levofloxacin (500 mg per day) was effective, although the results of antimicrobial susceptibility testing were unknown. Non-film-like, small, clear colonies were isolated on blood agar after 72 h of microaerobic incubation at 37 °C. Biochemical testing indicated that the isolates were catalase-positive, negative for nitrate reduction and urease activity, and positive for indoxyl acetate hydrolysis. The isolate was identified as CLO-3 by sequence analysis of the 16S rRNA and hsp60 genes. Although CLO-3 is known to cause enterocolitis, bacteremia due to CLO-3 has not been described. There have been an increasing number of reports of bacteremia caused by Helicobacter cinaedi and Helicobacter fennelliae, which were first reported as CLO-1 and CLO-2, and CLO-3 may represent another emerging cause of Helicobacter-induced bacteremia.

Helicobacter cinaedi and Helicobacter fennelliae are increasingly being reported as the causative organisms of bacteremia. These two species were first described as Campylobacter-like organism 1 (CLO-1) and Campylobacter-like organism 2 (CLO-2).Campylobacter-like organism 3 (CLO-3) was described in the same report as a cause of enterocolitis. A case of bacteremia due to CLO-3 is reported herein.

Helicobacter species are Gram-negative spiral-shaped bacteria that are categorized according to their pathology as gastric (such as Helicobacter pylori), enterohepatic, or hepatobiliary pathogens. More than 30 Helicobacter species have been reported. Non-H. pylori Helicobacter species are usually associated with gastrointestinal infections and bacteremia. However, the number of cases of bacteremia caused by these Helicobacter species is thought to be underestimated because they are fastidious, rarely grow on traditional culture media, and for certain diagnostic tests, a longer time may be required to obtain a positive result than for other organisms.

2. Case report

The case patient was a 75-year-old man with prostate cancer and prostate enlargement who routinely had an indwelling urethral catheter for urinary retention. He was receiving goserelin acetate (subcutaneous injection, 3.6 mg every 4 weeks) and bicalutamide (oral, 80 mg per day) to treat prostate cancer. There was no previous history of hepatobiliary disease or HIV infection, and he had not recently undergone a prostate biopsy. The patient was not a man who has sex with men and he had not had contact with pets or other animals.

Following a sudden fever he was admitted to the emergency department of Tokyo Medical University Hospital. His vital signs showed that he was febrile (38.0 °C), but were otherwise normal. He had no abnormal physical findings other than heat sensation and tenderness on rectal examination by the urologist. No gastric or enteric symptoms or skin lesions were observed. Laboratory tests showed an elevated white blood cell count (10.5 ×109 cells/l) with a left shift of neutrophils and a high C-reactive protein level (72 mg/l). Liver and biliary tract functions were normal and urinalysis indicated pyuria and hematuria. The patient was diagnosed with prostatitis, and one dose of ceftriaxone (1 g per dose) was administered in the emergency room after obtaining blood cultures (BD, Franklin Lakes, NJ, USA). Oral levofloxacin (500 mg per day) was selected for outpatient treatment on the basis of drug delivery for the prostate. A urethral catheter exchange was also performed. After a treatment period of 4 weeks, his clinical symptoms gradually improved and no recurrence was observed.

Table 1 Biochemical characteristics of the bacterial isolate compared with Helicobacter cinaedi, Helicobacter fennelliae, Helicobacter canis, and Campylobacter-like organism 3 (COL-3) Catalase Urease Nitrate reduction Indoxyl acetate hydrolysis Alkaline phosphatase Hippurate hydrolysis H. cinaedi + − + − − − H. fennelliae + − − + + − H. canis − − − + + − CLO-3 + − − + + − Current strain + − − + + − A urine culture obtained at this visit and prior to antibiotic administration was negative for all routine microbiological analyses following incubation for 2 days at 35 °C on 5% sheep blood agar (Nissui, Tokyo, Japan) and MacConkey II agar (BD). However, two aerobic bottles of the four blood cultures were positive for growth after 72 h of incubation. Gram stain showed spiral-shaped Gram-negative rods. Samples from these positive blood cultures were subcultured on 5% sheep blood agar (Nissui) and modified charcoal cefoperazone deoxycholate agar (mCCDA; BD). Non-film-like, small, clear colonies grew exclusively on 5% sheep blood agar under microaerobic conditions at 35 °C. Biochemical testing indicated that the isolates were catalase-positive, negative for nitrate reduction and urease activity, and positive for indoxyl acetate hydrolysis ( Table 1 ).

2 Funato M.

Kaneko H.

Ohkusu K.

Sasai H.

Kubota K.

Ohnishi H.

et al. Refractory chronic pleurisy caused by Helicobacter equorum-like bacterium in a patient with X-linked agammaglobulinemia. LC051629 ) was 87.5% identical (1524/1741 bp) to that of the H. fennelliae type strain CGUG518820 (GenBank accession number 3 Mikkonen T.P.

Karenlampi R.I.

Hanninen M.L. Phylogenetic analysis of gastric and enterohepatic Helicobacter species based on partial HSP60 gene sequences. LC051630 ) was compared to those in the NCBI GenBank database using the BLAST search tool, and the most closely related hsp60 gene sequence was that of Helicobacter canis (81%). However, BLAST analysis of the 16S rRNA sequence of TMUC1563 revealed 99.7% (1740/1745 bp) similarity to the corresponding region of Helicobacter sp CLO-3. Bacterial identification using API Campy tests (Sysmex bioMérieux, Tokyo, Japan) indicated H. fennelliae (85.7%) and Campylobacter jejuni (9.6%). To confirm the identity of the isolates, genomic DNA was extracted from the cultures by physical extraction using zirconia beads (MORA-extraction kit; AMR Co., Gifu, Japan), following the manufacturer's instructions. PCR amplification and sequencing were then performed to analyze the 16S rRNA gene. The universal primers 8UA (5′-AGAGTTTGATCMTGGCTCAG-3′) and 1485B (5′-ACGGGCGGTGTGTRC-3′) were used, as described previously.The resulting sequences were then analyzed using a GenBank BLAST search and EzTaxon ( http://www.ezbiocloud.net/eztaxon/ ). The 16S rRNA gene sequence obtained (GenBank accession number) was 87.5% identical (1524/1741 bp) to that of the H. fennelliae type strain CGUG518820 (GenBank accession number M88154 ), with the addition of 297 bp of sequence at nucleotide position 200 in the 16S rRNA sequence of the isolated strain. Sequence similarity between the 16S rRNA gene sequence of the novel isolate and the corresponding sequences of type strains from all other species of the genus Helicobacter ranged from 85.4% to 92.4%. The hsp60 gene of the novel isolate was also amplified and sequenced, as described previously.The hsp60 gene sequence (GenBank accession number) was compared to those in the NCBI GenBank database using the BLAST search tool, and the most closely related hsp60 gene sequence was that of Helicobacter canis (81%). However, BLAST analysis of the 16S rRNA sequence of TMUC1563 revealed 99.7% (1740/1745 bp) similarity to the corresponding region of Helicobacter sp CLO-3.