Persistent bacteremia due to Brevibacterium species in an immunocompromised patient

Brevibacterium Bacteremia in the Setting of Pyogenic Liver Abscess: A Case Report with Accompanying Literature Review

A 71-year-old Pakistani man with poorly controlled type 2 diabetes mellitus presenting with worsening mental status, abdominal pain, and oral intake for the past seven days was found to have pyogenic hepatic abscess with unculturable bacteria and subsequently found to have rare Brevibacterium bacteremia.

Successful Treatment of Brevibacterium Bacteremia Solely With Antimicrobial Therapy

Brevibacterium is a large genus that is not often involved in pathogenesis, however, since 1991 there have been several case reports of Brevibacterium-associated illness, most often due to bacteremia in the setting of an immunocompromised patient with a central venous catheter (CVC). Here we detail the case of an elderly woman with many comorbidities and a peripherally inserted central catheter (PICC) line for over four years, who presented with septic shock and Brevibacterium bacteremia. In nearly all previous cases of Brevibacterium bacteremia it was thought to be due to a CVC which was removed as part of the treatment in conjunction with antibiotics. In this case, the patient was treated with empiric antibiotics and her blood cultures cleared within 48 hours without catheter removal or antibiotic-lock therapy. The clinical outcome was favorable at 50 days follow-up.

Brevibacteria tibial osteomyelitis

Brevibacteria are Gram-positive rods found in human skin flora and dairy products. Although generally not considered human pathogens, case reports have implicated Brevibacterium species as rare causes of bacteremia, endocarditis, peritonitis, and osteomyelitis. We report a case of Brevibacterium tibial osteomyelitis in an immunocompetent individual with implanted hardware and highlight the challenge of identifying the organism and recognizing it as a potential pathogen.

Draft whole-genome sequence of Brevibacterium casei strain isolated from a bloodstream infection

Despite its low virulence potential and a commensal lifestyle as a member of the human skin microbiota, Brevibacterium casei has been increasingly reported as an opportunistic pathogen, especially in immunocompromised patients. Here, we present the draft genome sequence of the S51 strain isolated from a bloodstream infection. To the best of the authors’ knowledge, this is the first report of the draft genome sequence of the B. casei strain isolated from the clinical infection. The strain was identified using phenotypic and molecular methods and subsequently sequenced using the next-generation sequencing. The draft whole genome was assembled de novo, automatically annotated by Rapid Annotations using Subsystems Technology (RAST) server and scrutinized to predict the presence of virulence, resistance, and stress response proteins. The genome size of the S51 strain was 3,743,532 bp and an average G+C content was 68.3%. The predicted genes included 48 genes involved in resistance to antibiotics (including vancomycin, fluoroquinolones, and beta-lactams) and toxic compounds (heavy metals), 16 genes involved in invasion and intracellular resistance (Mycobacterium virulence operons), and 94 genes involved in stress response (osmotic, oxidative stress, cold and heat shock). ResFinder has indicated the presence of a beta-lactamase, and a phenotypic analysis showed resistance to penicillin. This whole-genome NGS project for the S51strain has been deposited at EMBL/GenBank under the accession no. QNGF00000000.

Brevibacterium paucivorans bacteremia: case report and review of the literature

Background

Brevibacteria are obligate aerobic gram-positive rods that are associated with milk products and are also found on human skin. Brevibacterium has been reported as a rare cause of catheter related blood steam infection mainly in immunocompromised hosts such as malignancies or AIDS patients.

Case presentation

A 94-year old woman, which had a past history of diabetes mellitus and chronic heart failure, presented with high fever associated with decreased oral intake and appetite loss and was admitted to our institute. A physical examination at the time of presentation was unremarkable. On day 2, both blood cultures collected on admission became positive with coryneform organism within 24 h without Staphylococci and Brevibacterium species were identified by Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Subsequently, genetic investigation by 16S ribosomal RNA analysis was performed in order to identify the organism. Finally, the result identified this pathogen as Brevibacterium paucivorans with 99.5% homology on the Ez taxon database.

The patient was started empirically on meropenem and teicoplanin for broad-spectrum antibiotic coverage. The patient’s fever finally abated and labs were also improved. On day 14, the antibiotic therapy was discontinued. The site of infections was unknown. We hereby report a case of Brevibacterium paicivorans bacteremia in an immunocompetent patient and review cases of Brevibacterium specises bacteremia previously reported. This is the first case of B. paucivorans bacteremia as far as we could search.

Conclusion

Physicians and microbiologists should be aware that Brevibacteria are uncommon but important agents which could cause opportunistic infections in immunocompetent.

Native aortic valve endocarditis caused by Brevibacterium epidermidis in an immunocompetent patient

Although Brevibacterium species used to be considered as nonpathogenic microorganisms until recently, it seems that they can cause a wide variety of clinical diseases by acting mostly as opportunistic pathogens. The present case is the second reported case of infective endocarditis by Brevibacterium species; however, it is the first reported infected native aortic valve in an immunocompetent patient.

Identification of a novel Brevibacterium species isolated from humans and description of Brevibacterium sanguinis sp. nov

Six coryneforms isolated from blood and dialysate fluid were phenotypically similar to Brevibacterium casei, but 16S rRNA gene sequencing and DNA-DNA hybridization indicate that they belong to a new species for which the name Brevibacterium sanguinis is proposed.

Management of long-term catheter-related Brevibacterium bacteraemia

Brevibacterium has been reported as a rare cause of implanted-device infection. In two cases of recurrent Brevibacterium casei bacteraemia associated with infection of surgically implanted intravascular devices, relapse occurred 2 and 5 months, respectively, after completion of therapy with vancomycin via the infected catheter. A second intravenous antibiotic therapy course by the antibiotic-lock technique led to bacteriological cure in one patient. Molecular typing results demonstrated that the recurrent bacteraemia was caused by the same strain. Implanted-device removal may be necessary, in addition to appropriate antibiotics, for successful management of such infections.

Brevibacterium endocarditis: a first report

There are few case reports of infections caused by Brevibacterium species, and there have been no previously reported cases of endocarditis caused by any of the 6 known species of Brevibacterium. We report the first case of Brevibacterium endocarditis (caused by Brevibacterium otitidis) in a patient with prosthetic heart valves. The patient responded to 6 weeks of treatment with vancomycin and 2 weeks with gentamicin, and she has been receiving long-term maintenance therapy with oral azithromycin.

Clinical microbiology of coryneform bacteria

Coryneform bacteria are aerobically growing, asporogenous, non-partially-acid-fast, gram-positive rods of irregular morphology. Within the last few years, there has been a massive increase in the number of publications related to all aspects of their clinical microbiology. Clinical microbiologists are often confronted with making identifications within this heterogeneous group as well as with considerations of the clinical significance of such isolates. This review provides comprehensive information on the identification of coryneform bacteria and outlines recent changes in taxonomy. The following genera are covered: Corynebacterium, Turicella, Arthrobacter, Brevibacterium, Dermabacter. Propionibacterium, Rothia, Exiguobacterium, Oerskovia, Cellulomonas, Sanguibacter, Microbacterium, Aureobacterium, "Corynebacterium aquaticum," Arcanobacterium, and Actinomyces. Case reports claiming disease associations of coryneform bacteria are critically reviewed. Minimal microbiological requirements for publications on disease associations of coryneform bacteria are proposed.

Antimicrobial susceptibility patterns of some recently established coryneform bacteria

The susceptibility patterns of 480 isolates representing six recently defined species of coryneform bacteria (Corynebacterium amycolatum [n = 101], Corynebacterium auris [n = 48], Corynebacterium glucuronolyticum [n = 86], Brevibacterium casei [n = 50], Dermabacter hominis [n = 49], and Turicella otitidis [n = 146]) to 17 antimicrobial agents were determined by an agar dilution method. Most significantly, for C. amycolatum strains the MICs at which 90% of isolates are inhibited were > or = 32 micrograms/ml for nearly all agents. However, all 480 strains examined were susceptible to glycopeptide antibiotics.

Recurrent bacteremia due to Brevibacterium casei in an immunocompromised patient

A case of an immunocompromised patient who experienced two episodes of septicemia caused by a coryneform bacterium is reported. Biochemical characteristics and analysis of cellular fatty acids and of cell wall components showed two identical strains of Brevibacterium casei to be responsible for these infections. The lack of easy-to-perform methods for identification may have led, in the past, to an underestimation of the role of this bacterium, especially in immunocompromised patients.

Bacteremia caused by Brevibacterium species in an immunocompromised patient

A 46-year-old woman suffering from non-Hodgkin's lymphoma was admitted to the hospital because of high fever. Multiple blood cultures revealed an unusual finding, a Brevibacterium species, which was reisolated 16 days later from the tip of her long-term central venous catheter. This case indicates that Brevibacterium species isolated from normally sterile sites should be considered as a potential pathogen, especially in immunocompromised patients.

Differentiation of Brevibacterium spp. encountered in clinical specimens

Forty-three strains belonging to the genus Brevibacterium which were encountered in clinical materials over 2 decades were compared with reference strains, including the type strains, of B. casei, B. epidermidis, B. mcbrellneri, B. iodinum, and B. linens. By means of carbohydrate assimilation tests (CATs) the 43 clinical isolates could be assigned to the species B. casei (n = 41) and B. epidermidis (n = 2). DNA-DNA hybridizations were performed for 20 clinical isolates and confirmed the species identification of the isolates. Cellular fatty acid profiles of all strains were determined and found to have less discriminative power than CATs. This is the first report indicating that most clinical Brevibacterium isolates are B. casei and that CATs provide an easy-to-perform method for species determination within the genus, thus avoiding nucleic acid techniques.