Ochrobactrum Anthropi; an Unusual Cause of Bacteremia and Pneumonia: A Case Report and a Brief Review of the Literature

Background: Ochrobactrum anthropi spp. is a non-enteric, aerobic gram-negative bacillus that has been reported to cause sepsis and occasionally bacteremia in both immunocompetent and immunocompromised hosts. This bacterium is capable of surviving in various habitats, but due to its affinity for aqueous environments, O. anthropi is hypothesized to have an affinity for indwelling plastic devices and other foreign bodies.

Case Presentation: We report a case of a 66 y/o male with a history of polysubstance abuse disorder admitted for toxic metabolic encephalopathy and found to have bronchopneumonia and bacteremia secondary to O. anthropi infection resulting in sepsis and cardiopulmonary arrest.

Discussion: Ochrobactrum spp. is an unusual pathogen of low virulence and has been noted to cause bacteremia and occasionally sepsis in both immunocompetent and immunosuppressed patients. Isolation of this pathogen in the appropriate setting should be considered a true pathogen and treated as such to avoid sequela of this infection.

Conclusion: This case report and literature review suggest that Ochrobactrum anthropi appears more frequently as a pathogen in nosocomial infections than suggested in the literature.

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Biliary sepsis caused by Ochrobactrum anthropi

Ochrobactrum anthropi is an emerging pathogen in immunocompromised patients, with the majority of human cases being central venous catheter-related infections. In contrast, O. anthropi-related biliary sepsis is much rare. Herein we report the clinical and microbiological characteristics of O. anthropi-related biliary sepsis in order to increase awareness of the potential role of O. anthropi in this infection. Further extensive epidemiologic studies should be carried out to ascertain the etiologic association between O. anthropi and biliary sepsis and to identify potential hosts and routes of transmission.

[Ochrobactrum anthropi bacteremia developed after cholangiopancreatography]

Ochrobactrum anthropi (formerly Achromobacter spp.) is an aerobic, motile, oxidase positive and lactose negative gram negative bacillus which is widely distributed in the environment and water sources. In recent publications, O. anthropi has an increasing importance as a nosocomial infection agent. The aim of this report was to present a case of O. anthropi bacteremia developed after endoscopic retrograde cholangiopancreatography (ERCP). A 89-year old female patient presented with high fever one day after ERCP performed due to klatskin tumour. O. anthropi had been grown in blood culture (BacT/ALERT 3D, bioMérieux, Durham, USA), and the isolate was identified by automatized system (VITEK, bioMerieux, Marcy l'Etoile, France). Since there was no clinical response to empirical ceftriaxone therapy, it was switched to meropenem, which was found effective by VITEK antibiotic susceptibility detection system. The patient was treated successfully with meropenem therapy (3 x 1 gr/day, 10 days). As a result, in case of suspected post-ERCP bacteremia, unconventional microorganisms such as O. anthropi should be taken into consideration.

Multidimensional proteomic analysis of the soluble subproteome of the emerging nosocomial pathogen Ochrobactrum anthropi

We report the first large-scale gel-free proteomic analysis of the soluble subproteome of the emerging pathogen Ochrobactrum anthropi. Utilizing our robust offline multidimensional protein identification protocol, a total of 57 280 peptides were initially identified utilizing automated MS/MS analysis software. We describe our investigation of the heuristic protein validation tool PROVALT and demonstrate its ability to increase the speed and accuracy of the curation process of large-scale proteomic datasets. PROVALT reduced our peptide list to 8517 identified peptides and further manual curation of these peptides led to a final list of 984 uniquely identified peptides that resulted in the positive identification of 249 proteins. These identified proteins were functionally classified and physiochemically characterized. A variety of typical "housekeeping" functions identified within the proteome included nucleic acid, amino and fatty acid anabolism and catabolism, glycolysis, TCA cycle, and pyruvate and selenoamino acid metabolism. In addition, a number of potential virulence factors of relevance to both plant and human disease were identified.

Pelvic abscess due to Ochrobactrum intermedium [corrected] in an immunocompetent host: case report and review of the literature

Ochrobactrum intermedium [corrected] infection is rare in humans and is generally associated with immunocompromised hosts with indwelling foreign bodies. We report a case of pelvic abscess with O. intermedium [corrected] after a routine appendectomy in an immunocompetent patient and review the literature on O. intermedium [corrected] infection in patients with normal immune function.

Ochrobactrum anthropi bacteraemia in immunocompetent children

Ochrobactrum anthropi is an emerging pathogen in immunocompromised patients but infections with the bacterium have very rarely been documented in normal hosts. We report the characteristics of O. anthropi bacteraemia in 11 immunocompetent children, aged 2 months to 7 y, hospitalized in a general hospital during a 5-y period. Children commonly presented with fever, non-specific respiratory or gastrointestinal manifestations, leukocytosis and neutrophilia and had a rapid recovery, even when they did not receive a specific treatment. In 10 cases positive blood cultures were obtained on admission and in all cases subsequent cultures were sterile. In conclusion, O. anthropi may cause bacteraemia in immunocompetent hosts, although further studies are required to clarify whether these isolates represent pseudobacteraemia or whether O. anthropi is a potential pathogen of low virulence.

Ochrobactrum anthropi bacteremia in pediatric oncology patients

Ochrobactrum anthropi is an emerging pathogen in immunocompromised hosts, particularly in patients with indwelling catheters. We report the characteristics of 14 O. anthropi bacteremic episodes in 11 children with Hickman-type central catheters. Children presented with fever and nonspecific clinical manifestations. Bacteremia was successfully treated with antibiotics, but catheter removal was necessary to achieve cure in four cases.