Hospital-acquired brevundimonas vesicularis septicaemia following open-heart surgery: case report and literature review

Comparative Genomic Analysis Reveals Potential Pathogenicity and Slow-Growth Characteristics of Genus Brevundimonas and Description of Brevundimonas pishanensis sp. nov

The genus Brevundimonas consists of Gram-negative bacteria widely distributed in environment and can cause human infections. However, the genomic characteristics and pathogenicity of Brevundimonas remain poorly studied. Here, the whole-genome features of 24 Brevundimonas type strains were described. Brevundimonas spp. had relatively small genomes (3.13 ± 0.29 Mb) within the family Caulobacteraceae but high G+C contents (67.01 ± 2.19 mol%). Two-dimensional hierarchical clustering divided those genomes into 5 major clades, in which clades II and V contained nine and five species, respectively. Interestingly, phylogenetic analysis showed a one-to-one match between core and accessory genomes, which suggested coevolution of species within the genus Brevundimonas. The unique genes were annotated to biological functions like catalytic activity, signaling and cellular processes, multisubstance metabolism, etc. The majority of Brevundimonas spp. harbored virulence-associated genes icl, tufA, kdsA, htpB, and acpXL, which encoded isocitrate lyase, elongation factor, 2-dehydro-3-deoxyphosphooctonate aldolase, heat shock protein, and acyl carrier protein, respectively. In addition, genomic islands (GIs) and phages/prophages were identified within the Brevundimonas genus. Importantly, a novel Brevundimonas species was identified from the feces of a patient (suffering from diarrhea) by the analyses of biochemical characteristics, phylogenetic tree of 16S rRNA gene, multilocus sequence analysis (MLSA) sequences, and genomic data. The name Brevundimonas pishanensis sp. nov. was proposed, with type strain CHPC 1.3453 (= GDMCC 1.2503^T= KCTC 82824^T). Brevundimonas spp. also showed obvious slow growth compared with that of Escherichia coli. Our study reveals insights into genomic characteristics and potential virulence-associated genes of Brevundimonas spp., and provides a basis for further intensive study of the pathogenicity of Brevundimonas.

IMPORTANCEBrevundimonas spp., a group of bacteria from the family Caulobacteraceae, is associated with nosocomial infections, deserve widespread attention. Our study elucidated genes potentially associated with the pathogenicity of the Brevundimonas genus. We also described some new characteristics of Brevundimonas spp., such as small chromosome size, high G+C content, and slow-growth phenotypes, which made the Brevundimonas genus a good model organism for in-depth studies of growth rate traits. Apart from the comparative analysis of the genomic features of the Brevundimonas genus, we also reported a novel Brevundimonas species, Brevundimonas pishanensis, from the feces of a patient with diarrhea. Our study promotes the understanding of the pathogenicity characteristics of Brevundimonas species bacteria.

Coming from the Wild: Multidrug Resistant Opportunistic Pathogens Presenting a Primary, Not Human-Linked, Environmental Habitat

The use and misuse of antibiotics have made antibiotic-resistant bacteria widespread nowadays, constituting one of the most relevant challenges for human health at present. Among these bacteria, opportunistic pathogens with an environmental, non-clinical, primary habitat stand as an increasing matter of concern at hospitals. These organisms usually present low susceptibility to antibiotics currently used for therapy. They are also proficient in acquiring increased resistance levels, a situation that limits the therapeutic options for treating the infections they cause. In this article, we analyse the most predominant opportunistic pathogens with an environmental origin, focusing on the mechanisms of antibiotic resistance they present. Further, we discuss the functions, beyond antibiotic resistance, that these determinants may have in the natural ecosystems that these bacteria usually colonize. Given the capacity of these organisms for colonizing different habitats, from clinical settings to natural environments, and for infecting different hosts, from plants to humans, deciphering their population structure, their mechanisms of resistance and the role that these mechanisms may play in natural ecosystems is of relevance for understanding the dissemination of antibiotic resistance under a One-Health point of view.

Metagenomics Analysis of Thrombus Samples Retrieved from Mechanical Thrombectomy

Purpose

The purpose of this study was to assess the microbiota in middle cerebral artery thrombi retrieved in mechanical thrombectomy arising out of symptomatic carotid plaque within 6 hours of acute ischemic stroke. Thrombi were subjected to next-generation sequencing for a bacterial signature to determine their role in atherosclerosis.

Materials and Methods

We included 4 human middle cerebral artery thrombus samples (all patients were male). The median age for the patients was 51±13.6 years. Patients enrolled in the study from Pacific Medical University and Hospital underwent mechanical thrombectomy in the stroke window period. All patients underwent brain magnetic resonance angiography (MRA) and circle of Willis and neck vessel MRA along with the standard stroke workup to establish stroke etiology. Only patients with symptomatic carotid stenosis and tandem lesions with ipsilateral middle cerebral artery occlusion were included in the study. Thrombus samples were collected, stored at –80 degrees, and subjected to metagenomics analysis.

Results

Of the 4 patients undergoing thrombectomy for diagnosis with ischemic stroke, all thrombi recovered for bacterial DNA in qPCR were positive. More than 27 bacteria were present in the 4 thrombus samples. The majority of bacteria were Lactobacillus, Stenotrophomonas, Pseudomonas, Staphylococcus, and Finegoldia.

Conclusion

Genesis of symptomatic atherosclerotic carotid plaque leading to thromboembolism could be either due to direct mechanisms like acidification and local inflammation of plaque milieu with lactobacillus, biofilm dispersion leading to inflammation like with pseudomonas fluorescence, or enterococci or indirect mechanisms like Toll 2 like signaling by gut microbiota.

Scombroid Poisoning with Concurrent Brevundimonas Septicemia: A Unique Case Report and Brief Literature Review

Scombroid poisoning is a predominantly self-limited illness associated with ingestion of poorly handled fish. It is not frequently associated with bacteremia and has never been described with Brevundimonas septicemia. We describe a case of a man who presented in shock with histamine poisoning after ingesting sushi. Blood cultures grew an uncommon pathogen, Brevundimonas vesicularis. This case demonstrates systemic bacterial infection in the setting of histamine poisoning, which is an atypical presentation for a well-known foodborne illness.

Brevundimonas spp: Emerging global opportunistic pathogens

Non-fermenting Gram-negative bacteria are problematic in clinical locations, being one of the most prevalent causes of nosocomial infections. Many of these non-fermenting Gram-negative bacteria are opportunistic pathogens that affect patients that are suffering with underlying medical conditions and diseases. Brevundimonas spp., in particular Brevundimonas diminuta and Brevundimonas vesicularis, are a genus of non-fermenting Gram-negative bacteria considered of minor clinical importance. Forty-nine separate instances of infection relating to Brevundimonas spp were found in the scientific literature along with two pseudo-infections. The majority of these instances were infection with Brevundimonas vesicularis (thirty-five cases – 71%). The major condition associated with Brevundimonas spp infection was bacteraemia with seventeen individual cases/outbreaks (35%). This review identified forty-nine examples of Brevundimonas spp. infections have been discussed in the literature. These findings indicate that infection review programs should consider investigation of possible Brevundimonas spp outbreaks if these bacteria are clinically isolated in more than one patient.

Microbiological Analysis of Surfaces of Leonardo Da Vinci's Atlantic Codex: Biodeterioration Risk

Following the discovery of discoloration on some pages of the Atlantic Codex (AC) of Leonardo da Vinci kept in the Biblioteca Ambrosiana in Milan, some investigations have been carried out to verify the presence of microorganisms, such as bacteria and fungi. To verify the presence of microorganisms a noninvasive method of sampling has been used that was efficient and allowed us to highlight the microbial facies of the material that was examined using conventional microbiological techniques. The microclimatic conditions in the storage room as well as the water content of the volume were also assessed. The combined observations allowed the conclusion that the discoloration of suspected biological origin on some pages of AC is not related to the presence or current attack of microbial agents.

A premature neonate with early-onset neonatal sepsis owing to Brevundimonas vesicularis complicated by persistent meningitis and lymphadenopathy

Human infection by Brevundimonas vesicularis is very rare, especially in children. A 29-week-old neonate is reported who developed early neonatal sepsis owing to B. vesicularis complicated by persistent meningitis and lymphadenopathy. B. vesicularis may be an emerging pathogen in neonatal infection.

Liver abscess caused by Brevundimonas vesicularis in an immunocompetent patient

Invasive infections caused by Brevundimonas vesicularis are very rare in humans. We experienced an unusual case of liver abscess due to B. vesicularis in an immunocompetent young male. The patient was successfully treated by liver abscess drainage and with antimicrobial therapy of ceftriaxone followed by ampicillin/sulbactam. The organism found in the aspiration culture of the abscess material was initially reported, by using a VITEK 2 system, as Sphingomonas paucimobilis. However, later, B. vesicularis was confirmed as the true pathogen through 16S rRNA gene sequencing. To our knowledge, this is the first case of liver abscess caused by B. vesicularis.

Spectrum of Brevundimonas vesicularis infections in neonatal period: a case series at a tertiary referral center

OBJECTIVES

To report infections caused by Brevundimonas vesicularis and the treatment regimens administered based on antibiotic studies of this Gram-negative bacterium in the neonatal period.

PATIENTS AND METHODS

Eight hospitalized neonates with positive blood cultures for Brevundimonas spp. were studied. Demographic data, clinical and laboratory findings, nutritional regimens, presence of primary disease, and the antibiotic regimens administered during the treatment of these neonates were noted. Antimicrobial susceptibility tests were performed on isolates of the positive cultures.

RESULT

Four neonates were preterm, and four were full-term infants. The underlying diseases--with the exception of being a neonate--were congenital heart disease (4 patients), respiratory distress syndrome (2), multiple congenital cerebral anomalies (1), and meconium aspiration syndrome (1). Septicemia was observed in all eight patients, while three also had concurrent meningitis. Multidrug resistance to the antimicrobials, including piperacillin-tazobactam, ceftazidime, and aztreonam, were identified in all eight infants; however, susceptibility to amikacin and imipenem was retained. All study patients responded to the antibiotic treatments and subsequent cultures were sterile. One patient died due to other causes.

CONCLUSIONS

We consider that until larger series are available, B. vesicularis should be regarded as virulent. Consequently, in this era of multi-resistant Gram-negative bacteria, serious B. vesicularis infections in neonates should be treated with a broad-spectrum agent, such as third-generation cephalosporin until the results of susceptibility testing are available. Our case reports demonstrate that the susceptibility of this organism to all aminoglycosides and third-generation cephalosporin is not uniform, but that most of the isolates are susceptible to imipenem. More treatment experience and more exact results from antimicrobial susceptibility testing are required to improve on present treatment regimens for invasive B. vesicularis infections.

Brevundimonas vesicularis bacteremia resistant to trimethoprim-sulfamethoxazole and ceftazidime in a tertiary hospital in southern Taiwan

BACKGROUND

Over the past 20 years, Brevundimonas vesicularis has rarely been reported as a pathogen causing human infection. The clinical manifestations of B. vesicularis bacteremia and its susceptibility to antibiotics has not been characterized.

METHODS

A retrospective study was conducted between 2006 and 2009 in a tertiary-care hospital in southern Taiwan.

RESULTS

A total of 22 cases of B. vesicularis bacteremia were identified during the study with 86% being community-acquired primary bloodstream infections. Of the 22 patients, 15 (68%) presented with fever, fewer comorbidities, shorter hospital stays, lower mean creatinine levels (1.10 mg/dL vs. 1.74 mg/dL), lower aspartate aminotransferase levels (29.1 IU/L vs. 79.0 IU/L), and lower alanine aminotransferase levels (16.4 IU/L vs. 67.0 IU/L) when compared to afebrile patients. Among the bacterial isolates, 90.9% were susceptible to cefpirome, imipenem and piperacillin/tazobactam while 86.4% were susceptible to gentamicin, amikacin and ciprofloxacin. However, 63.6% of the bacterial isolates were susceptible to ceftazidime, and only 59.1% were susceptible to trimethoprim-sulfamethoxazole (TMP-SMX). The 30-day mortality rate from all causes was 4.5%.

CONCLUSION

B. vesicularis is able to cause community-acquired and low-mortality primary bloodstream infections. The resistance of B. vesicularis to trimethoprim-sulfamethoxazole and ceftazidime limits the choice of available antibiotics for treatment.

Taxonomic characterisation of ceftazidime-resistant Brevundimonas isolates and description of Brevundimonas faecalis sp. nov

Three ceftazidime-resistant strains isolated from the sewage water of a municipal hospital in Palma de Mallorca, Spain, were analysed phenotypically and genotypically to clarify their taxonomic positions. Sequence determinations and phylogenetic analyses of the 16S rRNA genes indicated that strains CS20.3(T), CS39 and CS41 were affiliated with the species of the alphaproteobacterial genus Brevundimonas, most closely related to B. bullata, B. diminuta, B. naejangsanensis and B. terrae. Additional sequences analyses of the ITS1 region of the rRNA operon and the genes for the housekeeping enzymes DNA gyrase β-subunit and RNA polymerase β-subunit, genomic DNA-DNA hybridisation similarities, cell fatty acid profiles and physiological and biochemical characterizations supported the recognition of CS20.3(T) (CCUG 58127(T)=CECT 7729(T)) as a distinct and novel species, for which the name Brevundimonas faecalis sp. nov. is proposed. Strains CS39 and CS41 were ascribed to the species B. diminuta.

Brevundimonas vesicularis keratitis after laser in situ keratomileusis

A 45-year-old woman developed a corneal infiltrate 14 months after laser in situ keratomileusis (LASIK) enhancement in the left eye. The LASIK flap was lifted, scraped, and irrigated with fortified vancomycin and ceftazidime. Scraped samples were cultured and grew Brevundimonas vesicularis. The patient remained on topical ceftazidime until improvement was noted and was then switched to topical levofloxacin. The keratitis resolved on antibiotic agents with strong gram-negative coverage and a steroid. To our knowledge, this is the first report of a B vesicularis ocular infection.

The airborne metagenome in an indoor urban environment

The indoor atmosphere is an ecological unit that impacts on public health. To investigate the composition of organisms in this space, we applied culture-independent approaches to microbes harvested from the air of two densely populated urban buildings, from which we analyzed 80 megabases genomic DNA sequence and 6000 16S rDNA clones. The air microbiota is primarily bacteria, including potential opportunistic pathogens commonly isolated from human-inhabited environments such as hospitals, but none of the data contain matches to virulent pathogens or bioterror agents. Comparison of air samples with each other and nearby environments suggested that the indoor air microbes are not random transients from surrounding outdoor environments, but rather originate from indoor niches. Sequence annotation by gene function revealed specific adaptive capabilities enriched in the air environment, including genes potentially involved in resistance to desiccation and oxidative damage. This baseline index of air microbiota will be valuable for improving designs of surveillance for natural or man-made release of virulent pathogens.

A Cutaneous Infection Caused by Brevundimonas Vesicularis: A Case Report

Brevundimonas vesicularis is a non-fermenting gram-negative bacillus, aerobic and motile. This microrganism is ubiquitous in the environment and has rarely been implicated in human infections. We present the second case of cutaneous infection caused by B. vesicularis in an immunocompetent patient.

Brevundimonas vesicularis septic arthritis in an immunocompetent child

Septic arthritis is a rapidly destructive form of joint disease. The most common causative agents in children are Staphylococcus aureus and Kingella kingae, followed by group A Streptococcus and Streptococcus pneumoniae, and in neonates, enterobacteracea and group B Streptococcus. In this paper, we describe a previously healthy toddler with septic arthritis of the shoulder joint caused by Brevundimonas vesicularis. Prompt treatment with cefuroxime resulted in a full recovery. This is the first report of septic arthritis in humans caused by this microorganism, and the first description of B. vesicularis infection in an immunocompetent child.

Case report: infective endocarditis caused by Brevundimonas vesicularis

Background

There are few reports in the literature of invasive infection caused by Brevundimonas vesicularis in patients without immunosuppression or other predisposing factors. The choice of antimicrobial therapy for bacteremia caused by the pathogen requires more case experience to be determined.

Case presentation

The case of a 40-year-old previously healthy man with subacute endocarditis proposed to be contributed from an occult dental abscess is described. The infection was found to be caused by B. vesicularis on blood culture results. The patient recovered without sequelae after treatment with ceftriaxone followed by subsequent ciprofloxacin therapy owing to an allergic reaction to ceftriaxone and treatment failure with ampicillin/sulbactam.

Conclusion

To our knowledge, this is the first report of B. vesicularis as a cause of infective endocarditis. According to an overview of the literature and our experience, we suggest that third-generation cephalosporins, piperacillin/tazobactam, and ciprofloxacin are effective in treating invasive B. vesicularis infections, while the efficacy of ampicillin-sulbactam needs further evaluation.

Bacteriophages of freshwater Brevundimonas vesicularis isolates

Nine strains of Brevundimonas vesicularis were isolated from surface water of three ponds in Bielefeld, Germany. With those strains as indicators seven bacteriophages with different host ranges were isolated. Molecular characterization showed that all phages contained linear double-stranded DNA with a similar genome size of about 37 kb. Restriction analysis and hybridization of phage DNAs revealed that three of these phages are closely related to each other. These phages had morphologies typical of the family Siphoviridae. Their genomes contained cohesive ends. Four phages were classified into the family of Podoviridae. Restriction analysis of the DNAs of these phages did not reveal any similarities. The DNA of these phages were terminally redundant. All phages were unable to transduce plasmids or marker genes.