Two siblings with fatal Chromobacterium violaceum sepsis linked to drinking water

Chromobacterium violaceum infections in children: two case reports and literature review

PURPOSE

Chromobacterium violaceum(C. violaceum) is a gram-negative bacterium that rarely infects humans, especially children. However, the mortality rate is high and there are no clear guidelines for treatment. The aim of this paper is to increase clinicians' awareness of diseases caused by C. violaceum infections in children, to diagnose and treat them in a timely manner, to improve patient survival and to reduce mortality.

RESULTS

We analysed the latest paediatric-related English language literature over the last 10 years and summarised the latest mechanisms of injury, susceptibility factors, adverse prognostic and mortality predictors, mortality rates, methods to reduce mortality, clinical manifestations, new diagnostic methods, therapeutic agents and directions for future drug development for C. violaceum.

CONCLUSIONS

Based on the available data, we conclude that the possibility of C. violaceum infection should be considered and diagnosed when cellulitis, septicaemia and visceral abscesses develop in children with a history of skin injury and exposure to stagnant water or soil. When clinicians strongly suspect that a child is infected with this bacterium, the recommended medication is ciprofloxacin if the child presents with severe illness. If the child has a non-severe condition, medications with relatively fewer side effects for children can be chosen, such as gentamicin, trimethoprim/ sulfamethoxazole, imipenem, and other drugs. The physician can then adjust the antimicrobial regimen based on the antimicrobial spectrum after obtaining the drug sensitivity results.

The Regulatory Protein ChuP Connects Heme and Siderophore-Mediated Iron Acquisition Systems Required for Chromobacterium violaceum Virulence

Chromobacterium violaceum is an environmental Gram-negative beta-proteobacterium that causes systemic infections in humans. C. violaceum uses siderophore-based iron acquisition systems to overcome the host-imposed iron limitation, but its capacity to use other iron sources is unknown. In this work, we characterized ChuPRSTUV as a heme utilization system employed by C. violaceum to explore an important iron reservoir in mammalian hosts, free heme and hemoproteins. We demonstrate that the chuPRSTUV genes comprise a Fur-repressed operon that is expressed under iron limitation. The chu operon potentially encodes a small regulatory protein (ChuP), an outer membrane TonB-dependent receptor (ChuR), a heme degradation enzyme (ChuS), and an inner membrane ABC transporter (ChuTUV). Our nutrition growth experiments using C. violaceum chu deletion mutants revealed that, with the exception of chuS, all genes of the chu operon are required for heme and hemoglobin utilization in C. violaceum. The mutant strains without chuP displayed increased siderophore halos on CAS plate assays. Significantly, we demonstrate that ChuP connects heme and siderophore utilization by acting as a positive regulator of chuR and vbuA, which encode the TonB-dependent receptors for the uptake of heme (ChuR) and the siderophore viobactin (VbuA). Our data favor a model of ChuP as a heme-binding post-transcriptional regulator. Moreover, our virulence data in a mice model of acute infection demonstrate that C. violaceum uses both heme and siderophore for iron acquisition during infection, with a preference for siderophores over the Chu heme utilization system.

The First Fatal Case of Chromobacterium violaceum Infection in Japan

BACKGROUND Chromobacterium violaceum (C. violaceum) is a gram-negative and facultative anaerobic oxidase-positive bacillus generally seen in tropical or subtropical areas (latitudes between 35°N and 35°S). C. violaceum infection is a rare but serious infection with high morbidity and mortality rates. Most clinicians practicing in non-tropical counties, such as Japan, are unfamiliar with it. CASE REPORT We report the first fatal case of a 49-year-old man infected with C. violaceum after a traffic accident in Japan (latitude 34.8°N). The patient reported brief submergence in a marshy muddy rice field after the accident. There was some evidence of soil and water contamination of the patient's skin and clothing, but he denied swallowing water or soil. There were no findings of pneumonitis or severe open wounds on admission. Until the night of the 7th day of hospitalization, his general conditions remained stable despite a persistent fever. However, he suddenly collapsed on the 8th day of hospitalization and died. C. violaceum bacteremia led to fatal sepsis on dissemination to the iliopsoas abscess, which is a rare combination for this infection. CONCLUSIONS Episodes of exposure to contaminated water or soil, especially in summer, are important predisposing factors for C. violaceum infection. Thus, it is vital to include C. violaceum infections as a differential diagnosis, since the mortality rate of C. violaceum infections is high and the cases of this infection have increased in non-tropical counties.

Chromobacterium violaceum: A Review of an Unexpected Scourge

Chromobacterium violaceum is a common environmental bacterium that rarely causes disease in humans but has a high fatality rate if it does. Due to the rarity of the cases, clinicians are often unaware of the rapid progression of C. violaceum infection and its unexpected antibiotic resistance pattern, which contribute to the failure of patient management. Our review provides the clinical characteristics, possible sources of exposure, and comorbidities and determines factors associated with survival. We gathered information on 132 cases of C. violaceum causing disease in humans published between 1953 and 2020. Patients were predominantly male with a median age of 17.5, interquartile range (IQR) of 5.0-40.0 years, and a third of them were known to have immune deficiencies or comorbidities. Portals of entry were mainly through a wound in the leg and feet (28.0%), the torso (8.5%), or hands and arms (6.8%). It is not uncommon to acquire infection through unintended contact with contaminated water or dust through the mouth or inhalation. The median incubation period is 4.0 days (IQR 2.0-8.0 days) with a duration of clinical course of 17.5 days (IQR 8.0-30.8 days). The high rate of positive blood cultures (56.1%) and abscesses in internal organs (36.4%) shows the significant severity of this disease. Sepsis and Bacteremia were related to mortality with a risk ratio (RR) of 5.20 (95% CI, 0.831-32.58) and 2.14 (95% CI, 1.05-4.36), respectively. Appropriate antibiotic use prevented death at a RR 0.33 (95% CI, 0.21-0.52). Most patients who recovered and survived were treated with aminoglycosides, fluoroquinolones and carbapenems. This review shows the malignant nature of C. violaceum infection and the need for clinicians to be aware and provide prompt source management for patients. Appropriate empiric and targeted antibiotic regiment guided by susceptibility test results is of vital importance.

Fatal Infection Caused by Chromobacterium violaceum: A Case Report from a Tertiary Care Hospital in Bangladesh

Chromobacterium violaceum is a Gram-negative bacterium, found in tropical and subtropical regions. C. violaceum infection rarely occurs, but once occurs, it is associated with significant mortality due to severe systemic infection. Since the first human case from Malaysia in 1927, >150 cases of C. violaceum infection have been reported worldwide. We have described here a fatal case of C. violaceum infection in a tertiary care hospital in Dhaka, Bangladesh. To the best of our knowledge, this is the first case of C. violaceum infection in Bangladesh.

The Spectrum of Chromobacterium violaceum Infections from a Single Geographic Location

Chromobacterium violaceum is a bacterium associated with soil and water exposure in tropical regions and causes rare and serious clinical infections that are often fatal. We reviewed the demographic and clinical details of 28 patients with C. violaceum detected over 15 years from 2000 to 2015, from the Top End of the Northern Territory. Of these patients, 18 had infections attributable toC. violaceum Patients with infections were more commonly male (55.6%), and in the 16- to 60-year (61.1%) age group. Skin and soft tissue infections (50%), predominantly involving the limbs, were the major clinical manifestation. Water, mud exposure, and trauma were all noted as precipitating circumstances and comorbidities were present in 61.1% of the patients with infections. Of the 28 patients, 10 (35.8%) had C. violaceum isolated as an incidental finding or as asymptomatic colonization; these 10 patients did not require or receive therapy for C. violaceum bacterial infections. There were no relapsing infections in this group.Chromobacterium violaceum remains a serious infection, with seven patients (25%) in our series requiring intensive care management. However, the mortality rate (7.1%) in our series was far lower than previously described. This case series of C. violaceum infections from a single geographic area provides additional information of the characteristics of infection with this pathogen.