Retrospective Cohort Study on Delftia acidovorans Infections in Patients: A Rare and Significant Infection.

Background: In recent years, Delftia acidovorans has gained attention for its rare occurrence in patient infections. The literature consists mostly of case reports, necessitating further research to comprehensively understand risk factors, clinical characteristics, and management strategies. Methods: We conducted a retrospective cohort study involving patients diagnosed with Delftia acidovorans infection at a tertiary teaching hospital between January 2014 and December 2022. The data included demographic details, comorbidities, bacterial cultures, antibiotic susceptibility, and treatment outcomes. Results: There were 26 patients diagnosed with Delftia acidovorans infection who were predominantly older with multiple comorbidities. Approximately 76.9% of Delftia acidovorans infection patients had polymicrobial infections. Twenty-one patients had received antibiotics within three months before they developed the Delftia acidovorans infection, and these antibiotics were primarily third-generation cephalosporins, glycopeptides and fluoroquinolones. Antibiotic susceptibility testing showed resistance to aminoglycosides and susceptibility to imipenem, meropenem, ceftazidime, and piperacillin/tazobactam. Treatment outcome showed a mortality rate of 11.5%, mainly in patients with malignancy and advanced age. Conclusion: Delftia acidovorans infections predominantly affect older patients with multiple comorbidities. In terms of antibiotic therapy, carbapenems, cephalosporins, and piperacillin/tazobactam with antipseudomonal activity could all be considered.

Delftia acidovorans: An Unusual Pathogen from an Adenocarcinoma Lung Patient with Pleural Effusion.

Delftia acidovorans (D. acidovorans) is an aerobic, nonfermentative Gram-negative bacillus infrequently isolated from clinical specimens. The pathogenicity and clinical significance of the organism has not been ascertained due to uncommon clinical isolation and suspected low virulence. The organism has been reported to be inherently resistant to aminoglycoside group of drugs which remain as a widely used first-line drug of choice for febrile neutropenic patients. Hereby, we report a case of D. acidovorans-associated pleural effusion in a patient of metastatic adenocarcinoma diagnosed and treated timely and successfully with appropriate antibiotics.

Drinking-water isolated Delftia acidovorans selectively coaggregates with partner bacteria and facilitates multispecies biofilm development.

Coaggregation plays an important role in the development of multispecies biofilms in different environments, often serving as an active bridge between biofilm members and other organisms that, in their absence, would not integrate the sessile structure. The ability of bacteria to coaggregate has been reported for a limited number of species and strains. In this study, 38 bacterial strains isolated from drinking water (DW) were investigated for their ability to coaggregate, in a total of 115 pairs of combinations. Among these isolates, only Delftia acidovorans (strain 005P) showed coaggregating ability. Coaggregation inhibition studies have shown that the interactions mediating D. acidovorans 005P coaggregation were both polysaccharide-protein and protein-protein, depending on the interacting partner bacteria. Dual-species biofilms of D. acidovorans 005P and other DW bacteria were developed to understand the role of coaggregation on biofilm formation. Biofilm formation by Citrobacter freundii and Pseudomonas putida strains highly benefited from the presence of D. acidovorans 005P, apparently due to the production of extracellular molecules/public goods favouring microbial cooperation. This was the first time that the coaggregation capacity of D. acidovorans was demonstrated, highlighting its role in providing a metabolic opportunity for partner bacteria.

Whole-Genome Sequencing of a Multidrug-Resistant Strain: Delftia acidovorans B408.

BACKGROUND: Delftia acidovorans is distributed widely in the environment and has the potential to promote the growth of plants and degrade organic pollutants. However, it is also an opportunistic pathogen for human and many reports demonstrated that D. acidovorans has strong resistance to aminoglycosides and polymyxins. OBJECTIVE: The aim of this work was to reveal the antibiotic resistance genes and pathogenic genes in a novel conditional pathogenic strain-D. acidovorans B804, which was isolated from the radiation-polluted soil from Xinjiang Uyghur Autonomous Region, China. METHODS: The antibiotic resistance test was performed according to the Kirby-Bauer disk diffusion method and evaluated by the standards of the Clinical and Laboratory Standards Institute guidelines. The genome of D. acidovorans B804 was sequenced by a PacBio RS II and Illumina HiSeq 4000 platform in Shanghai Majorbio Biopharm Technology Co., Ltd. (Shanghai, China). RESULTS: The multidrug resistance phenotypes of D. acidovorans B804 was experimentally confirmed and its genome was sequenced. The total size of D. acidovorans B804 genome was 6,661,314 bp with a GC content of 66.73%. 403 genes associated with antibiotic resistances were predicted. Meanwhile, 89 pathogenic genes were also predicted and 17 of these genes might be capable of causing diseases to human, such as infections and salmonellosis. CONCLUSIONS: This genomic information can be used as a reference sequence for comparative genomic studies. The results provided more insights regarding the pathogenesis and drug resistance mechanism of D. acidovorans, which will be meaningful for developing more effective therapies toward D. acidovorans-related diseases.

Characteristics and Outcomes of Patients with Delftia acidovorans Infections: a Retrospective Cohort Study.

Delftia acidovorans (D. acidovorans) is a Gram-negative bacteria and an uncommon cause of human infections. This retrospective cohort study investigated clinical and microbiological characteristics and outcomes of patients with D. acidovorans infections. We included patients with culture-confirmed D. acidovorans infections attending Rigshospitalet, during 2002-2020. Fifty-nine patients with a median interquartile ranges (IQR) age of 47 (15-67) years were included. Thirty-five (59%) were males, and 57 (97%) had at least one comorbidity, including 25 (42%) with solid or hematologic malignancies. Eight (14%) were admitted to ICU, and 15 (25%) died within 365 days after infection. Persistent infection was found in 4 (6.8%) patients, and 41 (70%) had polymicrobial cultures, mainly with Pseudomonas spp. and Stenotrophomonas maltophilia. More than 85% of the D. acidovorans isolates were susceptible to meropenem or ceftazidime. Although, 88% and 62% of the isolates were resistant to gentamicin and colistin, respectively. D. acidovorans infections mainly affect patients with preexisting comorbidities, including malignancies. In the first year, all-cause mortality is considerable, polymicrobial cultures are common, and meropenem or cephalosporins with antipseudomonal activity could be the antibiotics of choice. IMPORTANCE Delftia acidovorans (D. acidovorans) is a Gram-negative bacteria that can cause infection in immunocompetent and immunocompromised individuals. The current knowledge comes mainly from case reports and case series. In this retrospective cohort study, we found that D. acidovorans infections mainly affect male patients with preexisting comorbidities, including malignancies. Persistent infections were not common, and most of the patients had polymicrobial cultures, mainly with Pseudomonas spp. and Stenotrophomonas maltophilia. More than 85% of the D. acidovorans isolates were susceptible to meropenem or ceftazidime. In contrast, 88% and 62% of the isolates were resistant to gentamicin and colistin, respectively.

Engineering and characterization of dehalogenase enzymes from Delftia acidovorans in bioremediation of perfluorinated compounds.

Per- and Polyfluorinated alkyl substances (PFAS) are a broad class of synthetic compounds that have fluorine substituted for hydrogen in several or all locations and are globally categorized as PFCs (perfluorochemicals; commonly called fluorinated chemicals). These compounds have unique chemical and physical properties that enable their use in non-stick surfaces, fire-fighting efforts, and as slick coatings. However, recent concerns over the health effects of such compounds, specifically perfluorooctanoic acid and perfluorooctane sulfonic acid (PFOA, PFOS; PFOA/S), have led to increased attention and research by the global community into degradation methods. In this study, soil samples from PFAS-contamination sites were cultured and screened for microbes with PFOA/S degradation potential, which led to the identification of Delftia acidovorans. It was found that D. acidovorans isolated from PFAS-contaminated soils was capable of growth in minimal media with PFOA as a sole carbon resource, and an observable fluoride concentration increase was observed when cells were exposed to PFOA. This suggests potential activity of a dehalogenase enzyme that may be of use in PFOA or PFAS microbial remediation efforts. Several associated haloacid dehalogenases have been identified in the D. acidovorans genome and have been engineered for expression in Escherichia coli for rapid production and purification. These enzymes have shown potential for enzymatic defluorination, a significant step in biological degradation and removal of PFOA/S from the environment. We hypothesize that bioremediation of PFAS using naturally occurring microbial degradation pathways may represent a novel approach to remove PFAS contamination.

Endophthalmitis due to Delftia acidovorans: An unusual ocular pathogen.

Endophthalmitis is a dreaded postoperative complication of cataract surgery. Delftia acidovorans is usually nonpathogenic and an unusual ocular pathogen. Isolated reports of delftia-associated sepsis, otitis media, endocarditis, keratitis, etc. exist in literature. We report a rare and unique case of delftia-related endophthalmitis in a 67-year-old male diagnosed 2 weeks after uneventful cataract surgery. He was treated successfully with core vitrectomy and intravitreal antibiotics. Microbiological evaluation of vitreous sample identified the causative organism as Delftia acidovorans. Post-vitrectomy fundus evaluation at 1 week revealed the presence of retinal vascular sheathing and sclerosis along with few retinal hemorrhages. Final visual recovery was poor due to the presence of macular edema, epiretinal membrane, and temporal disc pallor.

Delftia acidovorans pneumonia with lung cavities formation / Neumonia con formación de cavidades pulmonares causada por Delftia acidovorans

Abstract Case Description: A 52-year-old female patient was admitted to our clinic with complaints of cough, sputum, fever and fatigue. The patient has been receiving immunosuppressive therapy for thrombocytopenic purpura for 5 years. Clinical Finding: Inspiratory crackles were heard on both hemithorax. Oxygen saturation measured with the pulse oximeter was 97%. Chest X-ray showed diffuse reticular opacities that were more prominent in the upper zones of both lungs. WBC counts were 17,600 mm3 and Platelet counts were 29,000 mm3. Thorax CT showed that there were many thin-walled cavities and millimetric nodules accompanied by ground-glass infiltrates in the upper and middle lobes. Gram staining of bronchial fluid, taken by bronchoscopy, revealed Gram-negative bacilli and intense polymorphonuclear leukocytes. The bacteria were defined as Delftia acidovorans by BD Phoenix automated system. Treatment and outcomes: The patient was hospitalized with suspicion of opportunistic pulmonary infections and cavitary lung disease. After the empirical treatment of intravenous piperacillin-tazobactam and oral clarithromycin, her clinical and radiological findings significantly regressed, and she was discharged with outpatient follow-up. Clinical Relevance: This is the first example of cavitary pneumonia due to Delftia acidovorans in an immunocompromised patient. We would like to emphasize that Delftia pneumonia should be considered in the differential diagnosis of pulmonary cavitary involvement in such patients.

Resumen Descripción del caso: Una mujer de 52 años llegó a la clínica con tos, esputo, fiebre y fatiga. El paciente estuvo recibiendo terapia inmunosupresora durante 5 años para el tratamiento de la púrpura trombocitopénica. Hallazgo clínico: se escucharon crepitaciones inspiratorias en ambos hemitórax. La saturación de oxígeno fue del 97%. La radiografía de tórax mostró opacidades reticulares difusas que eran más prominentes en las zonas superiores de ambos pulmones. Los recuentos de leucocitos fueron de 17,600 mm3 y los recuentos de plaquetas fueron de 29,000 mm3. La TC de tórax mostró muchas cavidades de pared delgada y nódulos milimétricos acompañados de infiltrados vitrales en los lóbulos superior y medio. La tinción de Gram del líquido bronquial reveló bacilos gramnegativos y leucocitos polimorfonucleares. Las bacterias fueron identificadas como Delftia acidovorans. Tratamiento y resultados: La paciente fue hospitalizado con una sospecha de infección oportunista pulmonar y enfermedad pulmonar cavitaria. Después del tratamiento empírico de piperacilina-tazobactam intravenosa y claritromicina oral, los síntomas y signos retrocedieron significativamente, y fue dada de alta con seguimiento ambulatorio. Relevancia clínica: este es el primer registro de neumonía cavitaria causado por Delftia acidovorans en una paciente inmunocomprometida. Enfatizamos que la neumonía por Delftia debe considerarse en el diagnóstico diferencial de la afectación de la cavidad pulmonar en tales pacientes.

Delftia acidovorans: A rare cause of septic pulmonary embolism from catheter-related infection: Case report and literature review.

Septic pulmonary emboli is a rare condition due to the dislodgement of an infected thrombus traveling to the pulmonary vasculature via the venous system. Staphylococcus spp. and Candida spp. are the most common causative agents. The most common risk factor is intravenous drug abuse, but there has been an association with intravenous catheters. Delftia acidovorans (DA) is a rare organism causing catheter-related infection, which has a tendency to embolize and clog up major vessels. It is highly resistant to all available aminoglycoside agents. There are only a few cases reported in children showing DA as a cause of septic emboli with none of the cases reported in a young patient. We report a similar case but in a young adult who developed septic emboli due to DA that was caused by an infected peripherally inserted central catheter (PICC) line. Since the organism is highly susceptible to recurrent embolization, the PICC line was removed and the patient was treated successfully with an appropriate antibiotic regime.

Delftia acidovorans pneumonia with lung cavities formation.

CASE DESCRIPTION: A 52-year-old female patient was admitted to our clinic with complaints of cough, sputum, fever and fatigue. The patient has been receiving immunosuppressive therapy for thrombocytopenic purpura for 5 years. CLINICAL FINDING: Inspiratory crackles were heard on both hemithorax. Oxygen saturation measured with the pulse oximeter was 97%. Chest X-ray showed diffuse reticular opacities that were more prominent in the upper zones of both lungs. WBC counts were 17,600 mm3 and Platelet counts were 29,000 mm3. Thorax CT showed that there were many thin-walled cavities and millimetric nodules accompanied by ground-glass infiltrates in the upper and middle lobes. Gram staining of bronchial fluid, taken by bronchoscopy, revealed Gram-negative bacilli and intense polymorphonuclear leukocytes. The bacteria were defined as Delftia acidovorans by BD Phoenix automated system. TREATMENT AND OUTCOMES: The patient was hospitalized with suspicion of opportunistic pulmonary infections and cavitary lung disease. After the empirical treatment of intravenous piperacillin-tazobactam and oral clarithromycin, her clinical and radiological findings significantly regressed, and she was discharged with outpatient follow-up. CLINICAL RELEVANCE: This is the first example of cavitary pneumonia due to Delftia acidovorans in an immunocompromised patient. We would like to emphasize that Delftia pneumonia should be considered in the differential diagnosis of pulmonary cavitary involvement in such patients.

DESCRIPCIÓN DEL CASO: Una mujer de 52 años llegó a la clínica con tos, esputo, fiebre y fatiga. El paciente estuvo recibiendo terapia inmunosupresora durante 5 años para el tratamiento de la púrpura trombocitopénica. HALLAZGO CLÍNICO: se escucharon crepitaciones inspiratorias en ambos hemitórax. La saturación de oxígeno fue del 97%. La radiografía de tórax mostró opacidades reticulares difusas que eran más prominentes en las zonas superiores de ambos pulmones. Los recuentos de leucocitos fueron de 17,600 mm3 y los recuentos de plaquetas fueron de 29,000 mm3. La TC de tórax mostró muchas cavidades de pared delgada y nódulos milimétricos acompañados de infiltrados vitrales en los lóbulos superior y medio. La tinción de Gram del líquido bronquial reveló bacilos gramnegativos y leucocitos polimorfonucleares. Las bacterias fueron identificadas como Delftia acidovorans. TRATAMIENTO Y RESULTADOS: La paciente fue hospitalizado con una sospecha de infección oportunista pulmonar y enfermedad pulmonar cavitaria. Después del tratamiento empírico de piperacilina-tazobactam intravenosa y claritromicina oral, los síntomas y signos retrocedieron significativamente, y fue dada de alta con seguimiento ambulatorio. RELEVANCIA CLÍNICA: este es el primer registro de neumonía cavitaria causado por Delftia acidovorans en una paciente inmunocomprometida. Enfatizamos que la neumonía por Delftia debe considerarse en el diagnóstico diferencial de la afectación de la cavidad pulmonar en tales pacientes.

Exploitation of new endophytic bacteria and their ability to promote sugarcane growth and nitrogen nutrition.

Few studies have evaluated endophytic bacteria in relation to plant growth promotion, nitrogen uptake and biological control. The aim of this study was to molecularly and physiologically characterize thirteen endophytic bacteria strains, evaluate their biological control properties and their ability to promote plant growth and plant N nutrition. All the strains produced indole acetic acid and promoted increase of plant biomass, N accumulative amount and N-use efficiency index. None of the strains carries the nifH gene. Four strains stimulated plant nitrate reductase activity, four solubilized phosphate, nine produced siderophores and none produced HCN. Seven strains inhibited Bipolaris sacchari growth and one was antagonistic to Ceratocystis paradoxa. The pathogens were inhibited by the production of diffusible and volatile metabolites by the bacterial strains. Moreover, this is the first study to demonstrate the effect of Delftia acidovorans on sugarcane plant growth, nitrogen metabolism improvement and antagonism to B. sacchari. The most efficient strains in promoting plant growth and exhibiting antagonistic activities towards fungal pathogens were Herbaspirillum frinsingense (IAC-BECa-152) and three Pantoea dispersa strains (IAC-BECa-128, IAC-BECa-129, and IAC-BECa-132). These bacteria show potential to be used as inoculants for sustainable agricultural management, mainly at the seedling production phase.

Bioconversion of 16-dehydropregnenolone Acetate to Exclusively 4-androstene-3,17-dione by Delftia acidovorans MTCC 3363.

Delftia acidovorans MTCC 3363 was found to convert 16-dehydropregnenolone acetate (16-DPA) exclusively to 4-androstene-3, 17-dione (AD). Addition of 9α-hydroxylase inhibitors was not required for preventing the accumulation of byproducts. The effect of pH, temperature, substrate concentration, surfactants and carrier solvents on this bioconversion has been studied. 16-DPA was maximally converted in buffered medium at pH 7.0, at temperature 30°C and 0.5 mg ml-1 substrate concentration. Detergent addition and temperature above 35°C had deleterious effect on bioconversion. Dioxan was found to be the best carrier solvent for biotransformation of 16-DPA to AD.

Proteomic Analyses of Chlorhexidine Tolerance Mechanisms in Delftia acidovorans Biofilms.

Protein expression and fatty acid profiles of biofilm cells of chlorhexidine-tolerant Delftia acidovorans (MIC = 15 µg/ml) and its chlorhexidine-susceptible mutant (MIC = 1 µg/ml) were investigated. The chlorhexidine-susceptible mutant (MT51) was derived from the parental strain (WT15) using Tn5 transposon mutagenesis. The disrupted gene was identified as tolQ, a component of the tolQRAB gene cluster known to be involved in outer membrane stability. Proteomic responses of biofilm cells were compared by differential in-gel electrophoresis following exposure to chlorhexidine at sub-MIC (10 µg/ml) and above-MIC (30 µg/ml) concentrations. Numerous changes in protein abundance were observed in biofilm cells following chlorhexidine exposure, suggesting that molecular changes occurred during adaptation to chlorhexidine. Forty proteins showing significant differences (≥1.5-fold; P < 0.05) were identified by mass spectrometry and were associated with various functions, including amino acid and lipid biosynthesis, protein translation, energy metabolism, and stress-related functions (e.g., GroEL, aspartyl/glutamyl-tRNA amidotransferase, elongation factor Tu, Clp protease, and hydroxymyristoyl-ACP dehydratase). Several proteins involved in fatty acid synthesis were affected by chlorhexidine, in agreement with fatty acid analysis, wherein chlorhexidine-induced shifts in the fatty acid profile were observed in the chlorhexidine-tolerant cells, primarily the cyclic fatty acids. Transmission electron microscopy revealed more prominent changes in the cell envelope of chlorhexidine-susceptible MT51 cells. This study suggests that multiple mechanisms involving both the cell envelope (and likely TolQ) and panmetabolic regulation play roles in chlorhexidine tolerance in D. acidovorans. IMPORTANCE Delftia acidovorans has been associated with a number of serious infections, including bacteremia, empyema, bacterial endocarditis, and ocular and urinary tract infections. It has also been linked with a variety of surface-associated nosocomial infections. Biofilm-forming antimicrobial-resistant D. acidovorans strains have also been isolated, including ones displaying resistance to the common broad-spectrum agent chlorhexidine. The mechanisms of chlorhexidine resistance in D. acidovorans are not known; hence, a chlorhexidine-susceptible mutant of the tolerant wild-type strain was obtained using transposon mutagenesis, and the proteome and ultrastructural changes of both strains were compared under chlorhexidine challenge.

Assessment of biofilm formation of E. meningoseptica, D. acidovorans, and S. maltophilia in lens cases and their growth on recovery media.

PURPOSE: Bacterial biofilm formation in contact lens cases is a risk factor in the development of both microbial and infiltrative keratitis. This investigation evaluated three emerging pathogens: Stenotrophomonas maltophilia, Elizabethkingia meningoseptica, and Delftia acidovorans for biofilm formation and metabolic activity in lens cases. Also, growth of these bacteria on different media was assessed to optimize recovery conditions. METHODS: The three bacteria were incubated in lens cases with different concentrations of tryptic soy broth. Biofilm formation was evaluated by measuring metabolic activity using MTT and enumerating the number of viable bacteria. To determine the optimal recovery media, dilutions of these microorganisms were plated on six different media. The number of colony forming units (CFU) was recorded after 48, 72, and 96 h of incubation at 32°C and 37°C for S. maltophilia, and at 37°C for E. meningoseptica and D. acidovorans. RESULTS: All three microorganisms established biofilms in the lens cases, with significant numbers of CFU recovered. Biofilms of S. maltophilia and E. meningoseptica were metabolically active. Significant reduction in metabolic activity and number of viable S. maltophilia occurred when the incubation temperature was raised from 32°C to 37°C (p<0.05). The metabolic activity of the biofilms increased with greater organic load present. The highest percent recovery for all three organisms was given by Columbia blood agar, followed by chocolate. CONCLUSION: Based on the results, the presence of the three emerging pathogens present in lens cases and from corneal isolates can be accurately determined if proper growth media and incubation temperatures are utilized.

Delftia acidovorans: A rare pathogen in immunocompetent and immunocompromised patients.

Delftia acidovorans is an aerobic, nonfermenting Gram-negative bacillus. It is usually a nonpathogenic environmental organism and is rarely clinically significant. Although D acidovorans infection most commonly occurs in hospitalized or immunocompromised patients, there are also several reports documenting the infection in immunocompetent patients. The present article describes a B cell lymphoblastic leukemia patient with D acidovorans pneumonia who was successfully treated with antibiotic therapy. The present report indicates that unusual pathogens may be clinically significant in both immunocompromised and immunocompetent patients. D acidovorans is often resistant to aminoglycosides; therefore, rapid detection of this microorganism is important.

Le Delftia acidovorans est un bacille aérobie à Gram négatif sans pouvoir de fermentation. C'est un organisme généralement non pathogène présent dans l'environnement, qui est rarement significatif sur le plan clinique. Même si l'infection à D acidovorans s'observe surtout chez des patients hospitalisés ou immunodéprimés, plusieurs rapports le signalent chez des patients immunocompétents. Le présent article décrit un patient atteint d'une leucémie lymphoïde de type B compliquée par une pneumonie à D acidovorans éradiquée par antibiothérapie. D'après le présent rapport, des agents pathogènes inhabituels peuvent être cliniquement significatifs à la fois chez les patients immunodéprimés et chez les patients immunocompétents. Puisque le D acidovorans résiste souvent aux aminosides, il est important de le déceler rapidement.

Complete genome sequence of the phenanthrene-degrading soil bacterium Delftia acidovorans Cs1-4.

Polycyclic aromatic hydrocarbons (PAH) are ubiquitous environmental pollutants and microbial biodegradation is an important means of remediation of PAH-contaminated soil. Delftia acidovorans Cs1-4 (formerly Delftia sp. Cs1-4) was isolated by using phenanthrene as the sole carbon source from PAH contaminated soil in Wisconsin. Its full genome sequence was determined to gain insights into a mechanisms underlying biodegradation of PAH. Three genomic libraries were constructed and sequenced: an Illumina GAii shotgun library (916,416,493 reads), a 454 Titanium standard library (770,171 reads) and one paired-end 454 library (average insert size of 8 kb, 508,092 reads). The initial assembly contained 40 contigs in two scaffolds. The 454 Titanium standard data and the 454 paired end data were assembled together and the consensus sequences were computationally shredded into 2 kb overlapping shreds. Illumina sequencing data was assembled, and the consensus sequence was computationally shredded into 1.5 kb overlapping shreds. Gaps between contigs were closed by editing in Consed, by PCR and by Bubble PCR primer walks. A total of 182 additional reactions were needed to close gaps and to raise the quality of the finished sequence. The final assembly is based on 253.3 Mb of 454 draft data (averaging 38.4 X coverage) and 590.2 Mb of Illumina draft data (averaging 89.4 X coverage). The genome of strain Cs1-4 consists of a single circular chromosome of 6,685,842 bp (66.7 %G+C) containing 6,028 predicted genes; 5,931 of these genes were protein-encoding and 4,425 gene products were assigned to a putative function. Genes encoding phenanthrene degradation were localized to a 232 kb genomic island (termed the phn island), which contained near its 3' end a bacteriophage P4-like integrase, an enzyme often associated with chromosomal integration of mobile genetic elements. Other biodegradation pathways reconstructed from the genome sequence included: benzoate (by the acetyl-CoA pathway), styrene, nicotinic acid (by the maleamate pathway) and the pesticides Dicamba and Fenitrothion. Determination of the complete genome sequence of D. acidovorans Cs1-4 has provided new insights the microbial mechanisms of PAH biodegradation that may shape the process in the environment.

Microbiological characterization of Delftia acidovorans clinical isolates from patients in an intensive care unit in Brazil.

Delftia acidovorans is an opportunistic agent in several types of infections, both in immunocompromised and immune-competent individuals; its resistance to aminoglycosides and polymyxin, choice drugs for empirical treatment of Gram-negative infections, is remarkable. We report the antimicrobial susceptibility and the genetic relatedness of 24 D. acidovorans strains recovered from tracheal aspirates of 21 adult inpatients hospitalized in an intensive care unit at a Brazilian hospital, from 2012 to 2013. All of the isolates were recovered as pure cultures and in counts above 1,000,000 CFU/mL. None of them were susceptible to polymyxin B, amikacin, gentamicin, or tobramycin; quinolones and trimethoprim-sulfamethoxazole presented varied activities against the isolates, while ß-lactam resistance was not detected. Four clusters were verified in pulsed-field gel electrophoresis analysis, and a major pulsotype comprised 10 strains. A possible, but undetermined common source, can be responsible for this strain dissemination, underscoring the need of reinforcing the adherence to disinfection and infection control standard techniques.

Engineering Delftia acidovorans DSM39 to produce polyhydroxyalkanoates from slaughterhouse waste.

The inexpensive agricultural fatty by-products could be usefully converted to polyhydroxyalkanoates (PHAs) by properly selected and/or developed microbes. Delftia acidovorans DSM39 is a well-known producer of PHAs with high molar fractions of 4-hydroxybutyrate (4HB), but unable to grow on fatty substrates. The aim of this study was to construct a recombinant strain of D. acidovorans DSM39 using fats-containing waste such as udder, lard and tallow, to produce PHAs. The lipC and lipH genes of Pseudomonas stutzeri BT3, proficient lipolytic isolate, were successfully co-expressed into D. acidovorans DSM39 and the resulting recombinant strain displayed high extracellular enzymatic activity on corn oil. The PHAs production from corn oil achieved high levels (26% of cell dry weight, with about 7% of 4HB). Surprisingly, the recombinant strain produced greater values directly from slaughterhouse residues such as udder and lard (43 and 39%, respectively, with almost 7% of 4HB). Moreover, this work proved the ability of the recombinant D. acidovorans strain to produce PHAs with significant percentage of 4HB, without the supplementation of any precursor in the liquid broth. This research paves the way to the efficient one-step conversion of fatty residues into PHAs having valuable properties exploitable in several medical and industrial applications.

Delftia acidovorans as an Unusual Causative Organism in Line-Related Sepsis.

The problem of line-related sepsis in patients undergoing chemotherapy for malignant disease remains a major problem in cancer-care even into the third millennium. We report a highly unusual pathogen which represented both a diagnostic and treatment challenge and highlights important issues around patient education as well as laboratory capability in the identification of causative organisms in line-related infections to facilitate clinical management.

Fatal Delftia acidovorans infection in an immunocompetent patient with empyema.

Delftia acidovorans (earlier known as Comamonas acidovorans) is an aerobic, non-fermentative, Gram negative rod, classified in the Pseudomonas rRNA homology Group III. Reports of isolation of the organism from serious infections like central venous catheter associated bacteremia, corneal ulcers, otitis media exist. The microbiologists can identify this organism based on an orange indole reaction. This reaction demonstrates the organism's ability to produce anthranilic acid from tryptophan on addition of Kovac's reagent; which gives the media its characteristic "pumpkin orange" colour. Here we report the isolation of this organism from the Endotracheal tube aspirate of a 4 year old child. With the increasing use of invasive devices, it has become important to recognize these non fermentative gram negative bacilli as emerging source of infection even in immunocompetent individuals.