Brain empyema due to Ochrobactrum anthropi

Genomics of Ochrobactrum pseudogrignonense (newly named Brucella pseudogrignonensis) reveals a new bla OXA subgroup

Ochrobactrum pseudogrignonense (newly named Brucella pseudogrignonensis) is an emerging pathogen in immunodeficient and immunocompetent patients. Most documented cases associated with Ochrobactrum are frequently catheter-related and exhibit wide-spectrum β-lactam resistance. Misidentification of this pathogen using commercial bacterial identification kits is common. We identified a case of O. pseudogrignonense infection associated with cholelithiasis. The O. pseudogrignonense genome was sequenced and reconstructed using a Nanopore and Illumina hybrid strategy. A novel bla _OXA-919 divergent from existing OXA members was identified and subsequent analysis revealed its existence in all available O. pseudogrignonense genomes, which forms a new phylogenetic subgroup distinct from other OXA clusters. Further analysis demonstrated the presence of the novel bla _OXA-919 in the chromosome of several other Ochrobactrum species. Our study indicated that Ochrobactrum chromosomes may be a reservoir of bla _OXA-919 β-lactamases.

The Genus Ochrobactrum as Major Opportunistic Pathogens

Ochrobactrum species are non-enteric, Gram-negative organisms that are closely related to the genus Brucella. Since the designation of the genus in 1988, several distinct species have now been characterised and implicated as opportunistic pathogens in multiple outbreaks. Here, we examine the genus, its members, diagnostic tools used for identification, data from recent Ochrobactrum whole genome sequencing and the pathogenicity associated with reported Ochrobactrum infections. This review identified 128 instances of Ochrobactrum spp. infections that have been discussed in the literature. These findings indicate that infection review programs should consider investigation of possible Ochrobactrum spp. outbreaks if these bacteria are clinically isolated in more than one patient and that Ochrobactrum spp. are more important pathogens than previously thought.

Correct Identification of Ochrobactrum anthropi From Blood Culture Using 16rRNA Sequencing: A First Case Report in an Immunocompromised Patient in Mexico

The present report describes the misidentification of Brucella spp. from a positive blood culture using traditional microbiology tests. A molecular test identified the bacterium as Ochrobactrum anthropi. According to the information available, this report is the first to include this type of case in Mexico.

[A Case of Bacteremia Caused by Ochrobacterium intermedium]

We report herein on a case of bacteremia caused by Ochrobactrum intermedium (O. intermedium) identified with biotyper matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). An 86-year-old man was admitted to our hospital with paralysis of the right side of the body and dysphagia. He was diagnosed as having a pontine infarction based on the brain MRI findings and was admitted to hospital to have anti-platelet therapy. Three days after admission, he had a fever. Although he had redness and swelling at the peripheral venous catheter insertion site, he was diagnosed as having aspiration pneumonia, since he had fine crackles on auscultation. Soon after taking two sets of blood cultures and removal of the peripheral venous catheter, sulbactam/ampicillin (SBT/ABPC) was administrated. Fifty three hours after incubation, gram-negative bacilli was detected from an aerobic bottle and identified as O. intermedium with MALDI-TOF MS (Bruker MS). Antimicrobial chemotherapy was changed to meropenem (MEPM). He was treated for a total of seven days, and recovered without relapse. Infection caused by O. intermedium has been very uncommon, however, O. intermedium has been recognized as an emerging pathogen in immunodeficient and immunocompetent patients. Since identification of Ochrobactrum species by biochemical methods could be difficult, MALDI-TOF MS might be helpful to clarify Ochrobactrum species just as in the present case.