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.     

杭州地区77例普通型新型冠状病毒肺炎中医证候及病机特点初探

[目的]探讨脾虚型溃疡性结肠炎(ulcerative colitis,UC)患者的肠道菌群特征。[方法]收集2019年1月1日至2019年3月31日于浙江中医药大学附属第二医院、浙江省中医院、浙江省人民医院以及浙江大学附属第二医院门诊及住院的14例脾虚型UC患者、16例其他证型UC患者的粪便样本,同时收集同时间段至浙江中医药大学附属第二医院体检的8例健康者的粪便样本,提取三组粪便样本中菌群DNA,根据16S V3～V4区设计引物进行扩增,通过Illumina Miseq平台进行测序,以生物信息分析软件对测序结果进行分析,比较三组样本菌群组成和结构,分析脾虚型UC患者的肠道菌群特征。[结果]门分类水平上其他证型UC组中变形杆菌门的相对丰度显著高于健康人群组(P0.01)。属分类水平上,脾虚型UC组和其他证型UC组中分枝杆菌属、包西氏菌属、丁酸单胞菌属的相对丰度显著低于健康人群组(P0.05),而埃希氏菌属/志贺氏菌属、假单胞菌属的相对丰度明显高于健康人群组(P0.05)。此外,代尔夫特菌属的相对丰度在脾虚型UC组中明显低于其他证型UC组和健康人群组(P0.05)。[结论]脾虚型UC患者的肠道菌群特征与其他证型UC患者及健康人群相比存在一定的差异,代尔夫特菌属明显减少可能是脾虚型UC患者肠道菌群的特征性变化。     

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.     

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.     

Biodegradation of erythromycin by Delftia lacustris RJJ-61 and characterization of its erythromycin esterase

The residual erythromycin in fermentation waste can pollute the environment and threaten human health. However, there are no effective approaches to remedy this issue. In this study, an erythromycin-degrading bacterium named RJJ-61 was isolated and identified as a strain of Delftia lacustris based on morphological and phylogenetic analyses. The degradation ability of this strain was also evaluated; it could degrade 45.18% of erythromycin at 35°C in 120 h. Furthermore, the key degradation gene ereA was cloned from strain RJJ-61 and expressed in Escherichia coli BL21; the molecular weight of the expressed protein was ~45 kDa. The enzyme activity of EreA was 108.0 mU ml⁻¹ at 35°C and pH 7.0. Finally, the EreA protein was used to degrade erythromycin from mycelial dregs and 50% diluted solution, and the removal rates in them were 41.42% and 69.78%, respectively. In summary, D. lacustris RJJ-61 is a novel erythromycin-degrading strain that has great potential to remove erythromycin pollutants from the environment.