Roseomonas species infections in humans: a systematic review.

Roseomonas species have been recognized to cause infections in immunocompromised individuals. The purpose of this study was to systemically review all published cases of Roseomonas infections in humans and describe the epidemiology, microbiology, antimicrobial susceptibility, treatment and outcomes of these infections in humans. We performed a systematic review of PubMed (through 20th Octrober 2019) for studies providing epidemiological, clinical, microbiological as well as treatment data and outcomes of Roseomonas species infections. A total of 37 studies, containing data of 99 patients, were included in the analysis. The most common Roseomonas infections were those of the bloodstream in 74.7% (74 patients), musculoskeletal infections in 8.1% (8 patients), skin and soft tissue infections (SSTIs) and peritoneal dialysis-associated peritonitis in 6.1% (6 patients) each. Epidemiology of these infections differed, with bacteremias being more prevalent in patients with malignancy and central venous lines, musculoskeletal infections being more prevalent after orthopedic surgery, and SSTIs occurring without any reported underlying cause. Resistance to beta-lactams was very high with penicillin, piperacillin/tazobactam resistance and cephalosporin resistance at 96.6%, 90.7% and 77.8% respectively, while quinolone resistance was 9.1%. Quinolones, carbapenems and cephalosporins are the most common agents used for treatment, irrespectively of the infection site. Overall mortality was 3% (3 patients), with the mortality attributed to Roseomonas being at 1% (1 patient).

Increased P3HB Accumulation Capacity of Methylorubrum sp. in Response to Discontinuous Methanol Addition.

An alternative for non-biodegradable oil-based plastics has been the focus of many researchers throughout the years. Polyhydroxyalkanoates (PHAs) are potential substitutes due to their biodegradable characteristic and diversity of monomers that allow different biopolymer compositions and physical-chemical properties suitable for a variety of applications. The most well-known biopolymer from this class, poly(3-hydroxybutyrate) (P3HB), is already produced industrially, but its final price cannot compete with the oil-based plastics. As a low-volume high-value bioproduct, P3HB must be produced through a cheap and abundant feedstock, with high productivity and a feasible purity process in order to become an economically attractive bioproduct. In this scenario, we report a methylotrophic strain isolated from an estuarine contaminated site identified as Methylorubrum sp. highly tolerant to methanol and with great accumulation capacity of 60% (CDW) in 48 h through a simple strategy of batch fermentation with discontinuous methanol addition that could help lower P3HB's processing costs and final price.

Microvirga tunisiensis sp. nov., a root nodule symbiotic bacterium isolated from Lupinus micranthus and L. luteus grown in Northern Tunisia.

Three bacterial strains, LmiM8T, LmiE10 and LluTb3, isolated from nitrogen-fixing nodules of Lupinus micranthus (Lmi strains) and L. luteus (Llu strain) growing in Northern Tunisia were analysed using genetic, phenotypic and symbiotic approaches. Phylogenetic analyses based on rrs and concatenated gyrB and dnaK genes suggested that these Lupinus strains constitute a new Microvirga species with identities ranging from 95 to 83% to its closest relatives Microvirga makkahensis, M. vignae, M. zambiensis, M. ossetica, and M. lotononidis. The genome sequences of strains LmiM8T and LmiE10 exhibited pairwise Average Nucleotide Identities (ANIb) above 99.5%, significantly distant (73-89% pairwise ANIb) from other Microvirga species sequenced (M. zambiensis and M. ossetica). A phylogenetic analysis based on the symbiosis-related gene nodA placed the sequences of the new species in a divergent clade close to Mesorhizobium, Microvirga and Bradyrhizobium strains, suggesting that the M. tunisiensis strains represent a new symbiovar different from the Bradyrhizobium symbiovars defined to date. In contrast, the phylogeny derived from another symbiosis-related gene, nifH, reproduced the housekeeping genes phylogenies. The study of morphological, phenotypical and physiological features, including cellular fatty acid composition of the novel isolates demonstrated their unique profile regarding close reference Microvirga strains. Strains LmiM8T, LmiE10 and LluTb3 were able to nodulate several Lupinus spp. Based on genetic, genomic and phenotypic data presented in this study, these strains should be grouped within a new species for which the name Microvirga tunisiensis sp. nov. is proposed (type strain LmiM8T=CECT 9163T, LMG 29689T).

Skin microbiota is the main reservoir of Roseomonas mucosa, an emerging opportunistic pathogen so far assumed to be environmental.

Roseomonas spp. are increasingly involved in human infectious diseases. The environmental source for infection is generally admitted in published cases owing to the origin of most Roseomonas species and to their affiliation to the family Acetobacteraceae in Rhodospirillales, which mainly groups environmental bacteria. For a better delineation of Roseomonas habitat and infectious reservoir, we related phenotype, phylotype (16S rRNA gene), genomotype (pulsed-field gel electrophoresis) and origin of 33 strains isolated from humans, hospital environment and natural environment. Genetic and metagenomic databases were also surveyed. The population structure of the genus showed clades associated with humans, whereas others grouped environmental strains only. Roseomonas mucosa is the main human-associated species and the study supported the idea that opportunistic infections due to this species are related to the patient skin microbiota rather than to the environment. In contrast, some strains belonging to other species isolated from patients with cystic fibrosis were related to environmental clades, suggesting an exogenous source for patient colonization. Accurate knowledge about the reservoirs of opportunistic pathogens that have long been considered of environmental origin is still needed and would be helpful to improve infection control and epidemiological survey of emerging human pathogens.

Bacteremia due to imipenem-resistant Roseomonas mucosa in a child with acute lymphoblastic leukemia.

Roseomonas are described as opportunistic pathogens rarely involved in human infections. Their identification requires molecular methods and their antimicrobial susceptibility pattern varies according to the species. We report the first case of bacteremia due to Roseomonas mucosa in a child with leukemia and reviewed pediatric cases of Roseomonas infection, for which undoubted strain identification was available. Favorable outcome was observed despite resistance to numerous ß-lactams that may account for delayed effective treatment, suggesting the low virulence of Roseomonas in children. Here, the strain also displayed unusual resistance to imipenem, highlighting the possible acquisition of additional resistance by this pathogen.

Peritonitis caused by Roseomonas in a patient undergoing automated peritoneal dialysis: case report and literature review.

A 48-year-old man was admitted with cloudy dialysate and diagnosed as peritoneal dialysis (PD)-related peritonitis caused by Roseomonas infection. This is the third case of PD-related peritonitis due to Roseomonas species and also the first case of peritonitis in automated peritoneal dialysis. Despite its low virulence and rare incidence in peritoneal dialysis, clinicians should be alert to the possibility of Roseomonas infection due to its high resistance to antibiotics. Literature on Roseomonas infection is also reviewed. The current guidelines for empirical peritonitis in PD patients do not adequately cover such infection. Refractory treatment in high risk cases should alert clinicians to upgrade antibiotics even for a vague manifestation.

Clinical characteristics of infections caused by Roseomonas species and antimicrobial susceptibilities of the isolates.

Human infections due to Roseomonas species are uncommon and the vast majority of reported infections are opportunistic and easy to treat. We retrospectively reviewed the computerized database of the Bacteriology Laboratory at the National Taiwan University Hospital to identify patients with infections caused by Roseomonas species during the period January 2000 to December 2010. Isolates of Roseomonas species were confirmed by 16S rRNA gene sequencing analysis. During the study period, 20 patients had cultures positive for Roseomonas species. R. mucosa was the most prevalent isolate (n = 18), followed by 1 each of R. gilardii and Roseomonas genomospecies 5. True infection caused by Roseomonas species was confirmed in 17 (85%) patients. Most (n = 12, 71%) of these infections were health care-associated infection. The majority of the patients (n = 12, 71%) had underlying diseases. Malignancy was the most common underlying disease, and catheter-related bloodstream infection was the most common type of infection. The antimicrobial susceptibility patterns varied among the different Roseomonas species. In conclusion, Roseomonas species can cause infection in children and adults regardless of immune status. Because different Roseomonas species may have different clinical features and susceptibility profiles, molecular studies are necessary to identify Roseomonas isolates to the species level.

Isolation of bacterial strains from bovine fecal microflora capable of degradation of ceftiofur.

Ceftiofur, a third-generation cephalosporin used to treat bacterial infections in animals, is degraded in bovine feces but the specific bacteria involved are unknown. To find the bacteria involved in ceftiofur metabolism, the bovine fecal microflora was screened. Twenty-one nonidentical strains of bovine fecal bacteria were isolated on media containing 1-32 microg ml(-1) of ceftiofur. The cultures were incubated with 5 microg ml(-1) ceftiofur for different times, then centrifuged and analyzed by high-performance liquid chromatography. Three strains of Bacillus spp., two strains of Roseomonas spp., and one strain of Azospirillum sp. metabolized 5 microg ml(-1) ceftiofur in broth cultures in less than 24h; ten other strains of Roseomonas and one strain of Bacillus pumilus had metabolized it by 120 h. After the ceftiofur had been metabolized by these bacteria, the filter-sterilized supernatants of centrifuged cultures no longer inhibited the growth of a ceftiofur-sensitive strain of Kocuria rhizophila, which indicated that ceftiofur had been transformed to compounds without bactericidal activity. Each isolate was also found to be able to grow in the presence of other beta-lactams, and a nitrocefin assay showed beta-lactamase activity in the 17 strains that metabolized ceftiofur. The results show that some beta-lactamase-producing bacteria from the bovine fecal microflora are capable of transforming ceftiofur to metabolites lacking bactericidal activity.

Catheter-related bacteremia due to Roseomonas species in pediatric hematology/oncology patients.

Roseomonas is a newly described genus of pink-pigmented, gram-negative bacteria. Human infections caused by Roseomonas species are very rare. We report two cases of central venous catheter-related bacteremia associated with Roseomonas species (one case with R. gilardii and one with R. fauriae), and review the clinical spectrum of previously reported cases in the literature. Clinicals should be aware that Roseomonas species may cause serious infections in children.

Roseomonas infection associated with a left ventricular assist device.

Roseomonas species have been increasingly noted as causes of human infection. We present what we believe is the first case of left ventricular assist device (LVAD) infection secondary to Roseomonas. The clinical characteristics of Roseomonas infection and the pertinent features of LVAD infection are reviewed.