Clinical Characteristics of Ochrobactrum anthropi Bacteremia

Abstract

The clinical picture of Ochrobactrum anthropi infection is not well described because the infection is rare in humans and identification of the pathogen is difficult. We present a case of O. anthropi bacteremia that was initially misidentified as Ralstonia paucula and later identified by 16S rRNA sequencing and recA analysis. CASE REPORTA n 85-year-old man was admitted to our hospital to receive transcatheter arterial chemoembolization (TACE). He had liver cirrhosis (Child-Pugh score A) and hepatocellular carcinoma (HCC) caused by hepatitis C virus infection. His medical history included repeated radio frequency ablation and a total of nine TACE procedures for the treatment of HCC. He had also experienced urinary bladder and ureteral carcinoma.The patient was free from any complications; however, he suddenly developed high fever (39°C), chills, and rigors 12 days after TACE. Physical examination did not reveal any significant findings, but laboratory testing showed a highly inflammatory state: his white blood cell count was 17,700/mm 3 , and his C-reactive protein level was 4.5 mg/dl. Urine examination was normal, and whole-body computed tomography revealed no particular pathogenic lesion. An echocardiogram was not performed. Oral cefcapene pivoxil was prescribed for 1 week based on the suspicion of some forms of infection relating to TACE.Two sets of blood cultures were obtained at the time of high fever. Of these four bottles, two different aerobic bottles became positive for Gram-negative rods after an incubation period of 36 h. However, the patient's condition and laboratory measurements improved promptly, and he was discharged on day 16 without distinct diagnosis. Later, the organism was identified as Ralstonia paucula by the Microscan walkaway system (Siemens) with a concordance rate of 99.9%. Susceptibility testing showed the organism to be sensitive to imipenem, meropenem, amikacin, minocycline, and colistin but resistant to ␤-lactams such as piperacillin, piperacillin-tazobactam, ceftazidime, cefepime, aztreonam, levofloxacin, ciprofloxacin, gentamicin, and trimethoprim-sulfamethoxazole. Although the pathogen was resistant to the antibiotic prescribed, he responded well to the treatment and the antibiotic did not need to be changed.The organism had been rarely encountered at our hospital, and therefore the sample was sent to Kochi University for further identification. The two samples derived from different blood cultures were examined separately. Blood samples were inoculated onto agar media and incubated at 28°C. Pale yellow colonies grew in culture and released a popcorn-like smell. Almost the entire region of the 16S rRNA gene was amplified by colony PCR using a pair of primers (pr0R2, 5=-AGAGTTTGATCMTGGCTCAG-3=; 9Rev, 5=-AAGGAGGTGATCCAGCC-3=) and sequenced with the BigDye Terminator v3.1 cycle sequencing kit. The resulting sequences from the two samples were identical. BLAST analysis against the NCBI database revealed the organism not to be R. paucula but rather to be of the Ochrobactrum anthropi c...

Pacemaker and pacemaker lead infections due to Ochrobactrum anthropi: a case report

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Temperature-dependent regulation of theOchrobactrum anthropiproteome

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Ochrobactrum anthropi: An emerging pathogen causing meningitis with sepsis in a neurotrauma patient

“…Of them, O. anthropi is becoming increasingly recognized as an opportunistic and nosocomial pathogen. It is a non-fastidious, gram-negative, motile, non-fermenting bacillus with strict oxidative metabolism [2]. O. anthropi is considered as a potential pathogen in hospitals because it has microbial niche in water sources -normal saline, antiseptic solutions, dialysis fluids and on invasive medical devices on account of its ability to adhere to various synthetic materials [3].…”