Endocarditis infecciosa por Ochrobactrum anthropi en paciente inmunocompetente

Prevalence, Host Range, and Comparative Genomic Analysis of Temperate Ochrobactrum Phages

Ochrobactrum and Brucella are closely related bacteria that populate different habitats and differ in their pathogenic properties. Only little is known about mobile genetic elements in these genera which might be important for survival and virulence. Previous studies on Brucella lysogeny indicated that active phages are rare in this genus. To gain insight into the presence and nature of prophages in Ochrobactrum, temperate phages were isolated from various species and characterized in detail. In silico analyses disclosed numerous prophages in published Ochrobactrum genomes. Induction experiments showed that Ochrobactrum prophages can be induced by various stress factors and that some strains released phage particles even under non-induced conditions. Sixty percent of lysates prepared from 125 strains revealed lytic activity. The host range and DNA similarities of 19 phages belonging to the families Myoviridae, Siphoviridae, or Podoviridae were determined suggesting that they are highly diverse. Some phages showed relationship to the temperate Brucella inopinata phage BiPB01. The genomic sequences of the myovirus POA1180 (41,655 bp) and podovirus POI1126 (60,065 bp) were analyzed. Phage POA1180 is very similar to a prophage recently identified in a Brucella strain isolated from an exotic frog. The POA1180 genome contains genes which may confer resistance to chromate and the ability to take up sulfate. Phage POI1126 is related to podoviruses of Sinorhizobium meliloti (PCB5), Erwinia pyrifoliae (Pep14), and Burkholderia cenocepacia (BcepIL02) and almost identical to an unnamed plasmid of the Ochrobactrum intermedium strain LMG 3301. Further experiments revealed that the POI1126 prophage indeed replicates as an extrachromosomal element. The data demonstrate for the first time that active prophages are common in Ochrobactrum and suggest that atypical brucellae also may be a reservoir for temperate phages.

Clinical characteristics of Ochrobactrum anthropi bacteremia

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.

Specific detection and differentiation of Ochrobactrum anthropi, Ochrobactrum intermedium and Brucella spp. by a multi-primer PCR that targets the recA gene

Ochrobactrum anthropi, Ochrobactrum intermedium and Brucella spp. are phenotypically and genetically closely related pathogens that may cause disease with similar clinical presentation. Consequently, difficulties in their identification and differentiation have been reported. In this study, a sensitive recA gene-based multi-primer single-target PCR (MP-ST-PCR) was developed that allowed the specific detection and differentiation of these clinically relevant pathogens. The specificity of the assay was evaluated using a representative panel of 50 O. anthropi and 16 O. intermedium strains and the type strains of all Brucella spp. Detection limits for purified DNA from O. anthropi, O. intermedium and Brucella melitensis were 100, 10 and 100 fg, respectively. Brucella DNA was also successfully detected in various clinical specimens from a human patient with culture-proven brucellosis and from a Brucella-infected sheep and its aborted fetuses. The sensitivity of the MP-ST-PCR was comparable to that of an evaluated in-house Brucella real-time PCR assay. The developed assay closes a diagnostic gap and provides a simple but robust tool for the sensitive detection and correct identification of O. anthropi, O. intermedium and Brucella spp.

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.