Antimicrobial activity of violacein against oral bacteria associated with halitosis: an in vitro study

Introduction: violacein is a natural purple pigment produced by environmental bacteria that presents antimicrobial activity, particularly against Gram-positive bacteria. Intraoral halitosis (IOH) is a condition defined by the unpleasant odor emanating from the mouth, whose main source are volatile sulfur compounds, produced by Gram-negative oral bacteria on the tongue coating. In IOH treatment, antimicrobials have been indicated as chemical adjuncts, including natural products. Objective: thus, this study tested the antimicrobial activity of a violacein extract on key IOH-related bacteria (Porphyromonas gingivalis, Porphyromonas endodontalis, Fusobacterium nucleatum, Prevotella intermedia, Solobacterium moorei). Materials and Methods: bacteria were cultured in fastidious anaerobe blood agar in anaerobiosis, and 109 cells/ml suspensions were plated. Crude extract of violacein obtained from Chromobacterium violaceum was diluted in a 25% ethanol aqueous solution to 8, 4, 2, 1, 0.5 and 0.25 mg/ml. Using the disk agar diffusion method, 10 µl aliquots of each dilution were deposited on the seeded plates. Chlorohexidine (0.1%) and 25% ethanol solution were used as controls. Plates were incubated in anaerobiosis at 37°C for 72h, and the inhibition halos were recorded. Results: although chlorhexidine showed higher inhibition halos than the violacein extract, most species were inhibited at 4 and 8 mg/ml concentrations (p<0.05). P. gingivalis followed by F. nucleatum were the most affected species in relation to the other bacteria, although statistical significance was only reached for P. gingivalis (p<0.05). Conclusion: crude violacein extract from C. violaceum demonstrated antimicrobial activity against IOH-associated oral bacteria, being a potential antimicrobial to be studied as an adjunct in the control of IOH.

Introdução: a violaceína é um pigmento roxo natural produzido por bactérias ambientais que apresenta ação antimicrobiana, particularmente contra bactérias Gram-positivas. A halitose intraoral (HIO) é uma condição definida pelo odor desagradável que emana da boca, cuja principal fonte são os compostos sulfurados voláteis produzidos por bactérias Gram-negativas da saburra lingual. No tratamento da HIO, antimicrobianos têm sido indicados como adjuvantes, incluindo produtos naturais. Objetivo: assim, este estudo avaliou o potencial antimicrobiano de um extrato de violaceína em patógenos-chave da HIO (Porphyromonas gingivalis, Porphyromonas endodontalis, Fusobacterium nucleatum, Prevotella intermedia, Solobacterium moorei). Materiais e Métodos: bactérias foram cultivadas em meio ágar sangue para fastidiosos, em anaerobiose, e suspensões de 109 células/ml foram semeadas. O extrato bruto de violaceína obtido de Chromobacterium violaceum foi diluído em solução aquosa com 25% de etanol nas concentrações de 8, 4, 2, 1, 0,5 e 0,25 mg/ml. Através do método de disco difusão, 10 µl de cada diluição foram depositados nas placas semeadas. A clorexidina (0,1%) e a solução etanólica a 25% foram usadas como controles. As placas foram incubadas em anaerobiose a 37°C por 72h, e os halos de inibição foram registrados. Resultados: embora a clorexidina tenha apresentado os maiores halos de inibição do do que o extrato, a maioria das espécies foi inibida nas concentrações de 4 e 8 mg/ml (p<0,05). P. gingivalis e F. nucleatum foram as espécies mais afetadas em relação às outras bactérias, porém só foi observada significância estatística para P. gingivalis (p<0,05). Conclusão: o extrato bruto de violaceína de C. violaceum demonstrou atividade antimicrobiana contra bactérias orais associadas a HIO, sendo um potencial antimicrobiano a ser estudado como adjuvante no controle da HIO.

In vitro antibacterial-antibiofilm effect of Hypericum atomarium Boiss and chemical composition

Abstract Treatment with plant is considered an effective option against increased antibiotic resistance. In this study antibiofilm activity of methanol (CH3OH), chloroform (CHCl3), ethyl acetate (EtOAc) and water (H2O) extracts of Hypericum atomarium Boiss. which is member of Hypericum genus was evaluated in Pseudomonas aeruginosa PAO1 and antibacterial performance against Gram (+) and Gram (-) strains and also bioactive compounds of extract were analysed using by HPLC and GC-MS. According to antibacterial activity test results the extracts were effective all Gram (+) bacteria and Gram (-) Chromobacterium violaceum (MICs ranging from 0.42 µg/ml to 4.3 mg). Inhibition effect of biofilm formation was found to be different rate in extracts (methanol-63%, chloroform-52%). The major flavonoids were detected (−)-epicatechin (2388.93 µg/ml) and (+)-catechin (788.94 µg/ml). The main phenolic acids were appeared as caffeic acid 277.34 µg/ml and chlorogenic acid 261.79 µg/ml. And according to GC results α-pinene was found main compound for three solvent extracts methanol, chloroform and ethyl acetate 67.05, 62.69, 49.28% rate respectively

Chromobacteriosis (Chromobacterium violaceum) in a calf from Brazil - case report / Cromobacteriose (Chromobacterium violaceum) em um bezerro do Brasil - relato de caso

Chromobacterium violaceum is a rare opportunistic pathogen that causes highly fatal infections in domestic animals and humans. This report describes a fatal case suggestive of septicemia in a four-day-old female calf with chromobacteriosis. The calf had suppurative omphalophlebitis, suppurative fibrinous polyarthritis, anterior uveitis with bilateral fibrin deposition, fibrinous peritonitis, lymph node abscess and multifocal lymphocytic and neutrophilic encephalitis with multifocal hemorrhages. C. violaceum was isolated from the spleen and peri-renal lymph node and its identity was confirmed by PCR and sequencing. The pathogen was sensitive to azithromycin, gentamicin, enrofloxacin, norfloxacin, marbofloxacin, ciprofloxacin, erythromycin, sulphazotrim, fluorfenicol, tetracycline and doxycycline as well as resistant to penicillin, ampicillin, vancomycin, amoxicillin, amoxicillin + clavulanic acid, cephalothin, cephalexin, oxacillin, B polymyxin, neomycin and bacitracin. This is the first report of chromobacteriosis in a calf from Brazil.(AU)

Chromobacterium violaceum é um patógeno oportunista raro, que causa infecção fatal em animais domésticos e em humanos. Este relato descreve um caso fatal suspeito de septicemia em um bezerro de quatro dias, fêmea, infectado por C. violaceum. O bezerro apresentava onfaloflebite supurativa, poliartrite supurativa fibrinosa, uveíte anterior com deposição bilateral de fibrina, peritonite fibrinosa, abscesso de linfonodos e encefalite multifocal linfocítica e neutrofílica com áreas hemorrágicas multifocais. C. violaceum foi isolado no baço e no linfonodo, e sua identidade foi confirmada por PCR e sequenciamento. O patógeno foi sensível aos antibióticos azitromicina, gentamicina, enrofloxacina, norfloxacina, marbofloxacina, ciprofloxacina, eritromicina, sulfazotrim, florfenicol, tetraciclina, doxiciclina e foi resistente à penicilina, ampicilina, vancomicina, amoxicilina, amoxicilina + ácido clavulânico, cefalotina, cefalexina, oxacilina, polimixina B, neomicina e bacitracina. Este é o primeiro relato de cromobacteriose em bezerro no Brasil.(AU)

Septicemia por Chromobacterium Violaceum en pediatría / Septicemia due to Chromobacterium Violaceum in pediatrics

Chromobacterium violaceum es una bacteria gram negativa anaerobia facultativa, que se encuentra ampliamente distribuida en el agua y el suelo en regiones tropicales y subtropicales, que se asocia con infecciones respiratorias, gastrointestinales, abscesos hepáticos, meningitis, endocarditis, síndrome hemofagocítico y sepsis fulminante. Se presentan 2 casos en niños: el primero es un varón de 8 años con lesiones en piel, fiebre y adenitis inguinal, que ingresó con un cuadro de sepsis severa, síndrome de distrés respiratorio agudo (SDRA) y falleció a las 3 h del ingreso. De los hemocultivos se aisló Chromobacterium violaceum. El segundo caso, es una niña de 12 años con antecedente de fiebre y adenopatía inguinal secundaria a herida cortopunzante en el pie homolateral, que ingresó con un cuadro de sepsis, con desarrollo de abscesos múltiples profundos. De la colección obtenida de piel y partes blandas y de un aspirado traqueal se aisló Chromobacterium violaceum. Recibió tratamiento antibiótico adecuado y posteriormente fue dada de alta. Se realizó una revisión bibliográfica de esta infección en niños y se encontraron 44 casos en todo el mundo. Algunos de éstos, se relacionaron con inmunodeficiencia de base, como la enfermedad granulomatosa crónica. La infección por esta bacteria es rara y se presenta como un cuadro grave que no responde a antibióticos habituales de uso empírico y tiene una alta tasa de mortalidad (AU)

Chromobacterium violaceum is a facultative anaerobic Gramnegative bacillus, widely distributed in water and soil in tropical and subtropical regions and associated with respiratory and gastrointestinal infections, liver abscesses, meningitis, endocarditis, hemophagocytic syndrome, and fulminant sepsis. Here two pediatric cases are presented: The first was an 8-year-old boy with skin lesions, fever, and inguinal adenitis, who was admitted with severe sepsis, acute respiratory distress syndrome (ARDS) and died three hours after. Chromobacterium violaceum was isolated from blood cultures. The second case was a 12-year-old girl with a history of fever and inguinal adenopathy secondary to a wound in the homolateral foot, who was admitted because of sepsis and multiple deep abscesses. From samples collected from the skin and soft tissues as well as tracheal aspirate Chromobacterium violaceum was isolated. Adequate antibiotic treatment was started and the patient was subsequently discharged. In a review of the literature, 44 cases worldwide were identified. Some of these cases were related to underlying immunodeficiency, such as chronic granulomatous disease. Infection with this bacterium is rare and presents with severe manifestations that do not respond to the common empirical antibiotics and are associated with a high mortality rate (AU)

Anti-Candida and anti-quorum sensing activity of airborne microorganisms detected by a rapid method

Abstract INTRODUCTION: Introducing new antibiotics to the clinic is critical. METHODS: We adapted a plate method described by Kawaguchi and coworkers in 20131 for detecting inhibitory airborne microorganisms. RESULTS: We obtained 51 microbial colonies antagonist to Chromobacterium violaceum, purified and retested them, and of these, 39 (76.5%) were confirmed. They comprised 24 bacteria, 13 fungi, and 2 yeasts. Among the fungi, eight (61.5%) produced active extracts. Among the bacterial, yeast, and fungal strains, 17 (44.7%) and 12 (31.6%) were active against Candida albicans and Candida parapsilosis, respectively. CONCLUSIONS: The proposed screening method is a rapid strategy for discovering potential antibiotic producers.

Identification of Chromobacterium violaceum by MALDI-TOF mass spectrometry in blood culture

Report of Chromobacterium violaceum isolation from blood culture. Identification by MALDI-TOF mass spectrometry. Relevant report due to the site affected, infection severity, and importance of correct and rapid identification for a successful treatment and lower risk of morbidity and mortality. (AU)

Reporte de dos casos de inusual infección no letal por Chromobacterium violaceum. Revisión literaria / Report two cases non lethal infectious diseases for Chromobacterium violaceum. Review of the literature

Chromobacterium violaceum es una bacteria gramnegativa anaeróbica facultativa, que habita en el suelo y el agua de las áreas tropicales y subtropicales. La infección en seres humanos es rara. A continuación se presentan dos casos; una lactante mayor, indígena, quien posterior a baño de inmersión en aguas estancadas comienza a presentar fiebre con aumento de volumen y limitación funcional y gonalgia izquierda, se realiza lavado articular, se toma muestra para cultivo con crecimiento para Chromobacterium violaceum. Un escolar masculino de 7 años de edad con antecedente de Leucemia Linfoblastica Aguda con recaída en sistema nervioso central, cumpliendo esquema de altas dosis de metotrexate; quien comienza a presentar fiebre y signos de flogosis en sitio de colocación de cáteter de vía central, el cual es retirado y cultivado con crecimiento para Chromobacterium violaceum. Esta infección en humanos es una enfermedad grave y sistémica con una alta tasa de mortalidad.

Chromobacterium violaceum is a Gram-negative facultative anaerobic bacterium, which lives in the soil and water of subtropical and tropical areas. Infection in humans is rare. Here we present two cases. One was in one indigenous newborn, who after one immersion in stagnant waters presented fever and increase in the volume of testicle and limitation in movility of the left limb. After arthrocentesis of left knee and culture of the sinovial liquid, growth of Cromabacterium violaceum was reported. Another case was a male school of 7 years old with a history of acute lymphoblastic leukemia relapse in the central nervous system, that completed his high dose methotexate scheme. Some days after he presented fever and edema at the site of central venous catheterization. The catheter was retired and it was obtained growth of Chromobacterium violaceum. Human infection with Chromobacterium violaceum is a severe and systemic disease with a high mortality rate.

Chromobacterium violaceum (Schröter 1872) isolated from the aquatic environment associated with the fish culture of Jaú, Zungaro jahu (Ihering, 1898) (Siluriformes, Pimelodidae) / Chromobacterium violaceum (Schröter 1872) isolado de ambiente aquático associado à piscicultura de Jaú, Zungaro jahu (Ihering, 1898) (Siluriformes, Pimelodidae) piscicultura

The jau, Zungaro jahu (Ihering, 1898) is an endangered species, rheophilic, reaching 1.5 m and more than 100 kg. During a work of microbiological monitoring of water quality, in the cultivation of Zungaro jahu, microorganisms that were isolated, were previously reported in other studies, as family members Enterobacteriaceae, Staphylococcus and non-fermenting bacilli. However, it was also isolated Chromobacterium violaceum, which despite being a bacterium found in such an environment, it was reported linked to the cultivation of fish. This paper describes the Chromobacterium violaceum founded in a psiculture, which has implications for national fish farming.

O jaú, Zungaro jahu (Ihering, 1898), é uma espécie em extinção, reofílica, atingindo 1,5 m e mais que 100 kg. Durante um trabalho de monitoramento microbiológico da qualidade da água, no cultivo da espécie em foco, foram isolados microrganismos previamente descritos em outros estudos, como membros da família Enterobacteriaceae, Staphylococcus e bacilos não fermentadores. Além desses microrganismos, foi isolada também a espécie Chromobacterium violaceum, que apesar de ser uma bactéria encontrada neste tipo de ambiente, não foi relatada associada ao cultivo de peixes. Este trabalho relata este importante achado, que pode trazer implicações à piscicultura nacional.

Efeito da violaceína sobre formas evolutivas de trypanosoma cruzi

A Organização Mundial de Saúde estima que aproximadamente 7 a 8 milhões de pessoas encontram-se infectadas pelo Trypanosoma cruzi no mundo. O tratamento da doença de Chagas apresenta eficácia limitada e efeitos colaterais que limitam a tolerabilidade e a adesão dos pacientes. A busca de novas alternativas terapêuticas a partir de substâncias bioativas cresceu bastante nos últimos anos. A violaceína (VIO), um pigmento bacteriano produzido por Chromobacterium violace um tem mostrado diversas ações biológicas, dentre elas, ações antiulcerogênica, antitumoral, antiviral e antiparasitária. No presente trabalho, estudamos os efeitos da VIO sobre as formas evolutivas doTrypanosoma cruzi. As formas epimastigotas foram cultivadas em meio LIT, a 28°C, na presença deVIO (0,97; 1,9; 3,9; 7,8; 15,62; 31,25; 62,5; 125; 250; 500; 1000μM) por 24, 48 e 72h. As formas tripomastigotas, foram obtidas após infecção em células LLC-MK2, ressuspensas em meio DMEM2% de SBF e incubadas com VIO (0,97; 1,9; 3,9; 7,8; 15,62; 31,25μM) por 24h. Formas amastigotas foram cultivadas em lamínulas circulares no interior de placas de cultura contendo células LLC-MK2e tratadas com violaceína (4,97 e 9,94 μM)...

The World Health Organization estimates that approximately 7 to 8 million individuals areinfected with Trypanosoma cruzi worldwide. The treatment of Chagas disease has limited efficacy andside effects that limit patient tolerability and compliance. The search for new therapeutic alternativesbased on bioactive substances has increased significantly in recent years. Violacein (VIO), a bacterialpigment produced by Chromobacterium violaceum, has shown several biological actions and amongthem, antiulcer, antitumor, antiviral, and antiparasitic action. In this study, we assessed the effects ofVIO on the evolutionary forms of Trypanosoma cruzi. Epimastigotes were cultured in liver infusiontryptose (LIT) medium at 28 °C in the presence of VIO (0.97; 1.9; 3.9; 7.8; 15.62; 31.25; 62.5; 125;250 ; 500; 1000μM) for 24, 48 and 72 hours. Trypomastigotes were obtained after infection in LLCMK2cells resuspended in 2% DMEM medium of FBS and incubated with VIO (0.97; 1.9; 3.9; 7.8;15.62; 31.25μM ) for 24h. Amastigotes were cultured on circular glass slides within culture platescontaining LLC-MK2 cells and treated with violacein (4.97 and 9.94 μM)...

Composition, anti-quorum sensing and antimicrobial activity of essential oils from Lippia alba

Many Gram-negative pathogens have the ability to produce N-acylhomoserine lactones (AHLs) as signal molecules for quorum sensing (QS). This cell-cell communication system allows them to coordinate gene expression and regulate virulence. Strategies to inhibit QS are promising for the control of infectious diseases or antibiotic resistant bacterial pathogens. The aim of the present study was to evaluate the anti-quorum sensing (anti-QS) and antibacterial potential of five essential oils isolated from Lippia alba on the Tn-5 mutant of Chromobacterium violaceum CV026, and on the growth of the gram-positive bacteria S. aureus ATCC 25923. The anti-QS activity was detected through the inhibition of the QS-controlled violacein pigment production by the sensor bacteria. Results showed that two essential oils from L. alba, one containing the greatest geranial:neral and the other the highest limonene:carvone concentrations, were the most effective QS inhibitors. Both oils also had small effects on cell growth. Moreover, the geranial/neral chemotype oil also produced the maximum zone of growth inhibition against S. aureus ATCC 25923. These data suggest essential oils from L. alba have promising properties as QS modulators, and present antibacterial activity on S. aureus.

Chromobacterium violaceum: um caso fatal no nordeste do Brasil / Chromobacterium violaceum: a fatal case in the northeast of the Brazil

Chromobacterium violaceum is a rare pathogen that can potentially cause fatal infections in humans. An 8-year-old child from Natal, northeast of Brazil, presented history of fever, sore throat, and abdominal pain, during 5 days before admission, and died 4 hours after hospitalization. Chromobacterium violaceum was isolated from oropharynx scrapings and was resistant to ampicillin, cefotaxime, cefalotin, ceftazidime, and ceftriaxone...

Chromobacterium violaceum é um patógeno raro que potencialmente pode causar infecções fatais em humanos. Relatamos o caso de uma criança de 8 anos de idade, moradora da cidade de Natal, nordeste do Brasil, que apresentou história de febre, dor na garganta e no abdome durante os cinco dias anteriores à internação, e veio a falecer após 4 horas de hospitalização. A bactéria Chromobacterium violaceum foi isolada da orofaringe e apresentou resistência a ampicilina, cefotaxima, cefalotina, ceftazidima e ceftriaxona...

In vitro and in vivo antitumor activity of crude extracts obtained from Brazilian Chromobacterium sp isolates

Natural products produced by microorganisms have been an important source of new substances and lead compounds for the pharmaceutical industry. Chromobacterium violaceum is a Gram-negative β-proteobacterium, abundant in water and soil in tropical and subtropical regions and it produces violacein, a pigment that has shown great pharmaceutical potential. Crude extracts of five Brazilian isolates of Chromobacterium sp (0.25, 2.5, 25, and 250 µg/mL) were evaluated in an in vitro antitumor activity assay with nine human tumor cells. Secondary metabolic profiles were analyzed by liquid chromatography and electrospray ionization mass spectrometry resulting in the identification of violacein in all extracts, whereas FK228 was detected only in EtCE 308 and EtCE 592 extracts. AcCE and EtCE 310 extracts showed selectivity for NCI/ADR-RES cells in the in vitro assay and were evaluated in vivo in the solid Ehrlich tumor model, resulting in 50.3 and 54.6% growth inhibition, respectively. The crude extracts of Chromobacterium sp isolates showed potential and selective antitumor activities for certain human tumor cells, making them a potential source of lead compounds. Furthermore, the results suggest that other compounds, in addition to violacein, deoxyviolacein and FK228, may be involved in the antitumor effect observed.

Biosurfactant production by Chr omobacterium violaceum ATCC 12472 using corn steep liquor and corn post-frying oil as nutrients / Produção de biossurfactante por Chromobacterium violaceum ATCC 12472 utilizando milhocina e óleo de milho pós-fritura como nutrientes

The interest in microbial surfactants has been increased considerably in the recent years. Environmental concern among consumers, combined with new laws control of the environment, the demand for natural surfactants, to replace petrochemicals. The microbial surfactants have been tested in many industrial and environmental applications, such as in bioremediation, oil dispersion and oil recovery, replacing chemical surfactants. Furthermore, they can also be used in the food, cosmetic, detergent and agriculture. However, increased environmental concern among consumers to new legislation combined control of the environment has led to demand for natural surfactants as alternatives to existing products. This work aimed to produce biosurfactant by Chromobacterium violaceum ATCC 12472, using low nutrient value. The surface tension of the biosurfactant produced by C. violaceum ATCC 12472 had values between 29 and 40 mN/m. The best result was observed on the assay 8 (8.0% of corn steep liquor, 1.0% of lactose and corn oil post-frying 7.5%) factorial design, within 72 hours of fermentation, lowering the surface tension of water from 71 to 29 mN/m. The best results of the index (E24) and emulsification activity (UEA) were observed in the central point, and using the both methods and corn post-frying oil resulted in 72% of emulsification, and the emulsification activity value of 6 UAE. The results demonstrate the high potential of C. violaceum promising in producing a biosurfactant.

O interesse em surfactantes de origem microbiana tem aumentado consideravelmente nos últimos anos. A preocupação ambiental entre os consumidores, combinada às novas legislações de controle do meio ambiente, aumentou a procura por surfactantes naturais em substituição aos derivados petroquímicos. Os surfactantes microbianos têm sido testados em muitas aplicações ambientais e industriais, como na biorremediação, na dispersão de manchas oleosas e na recuperação de petróleo, substituindo os surfactantes químicos. Além disso, também podem ser utilizados nas indústrias de alimentos, cosméticos, detergentes e na agricultura. Neste trabalho foi produzido biossurfactante por Chromobacterium violaceum ATCC 12472, utilizando nutrientes de baixo valor agregado. A tensão superficial do biossurfactante produzido por C. violaceum ATCC 12472 teve valores entre 29 e 40 mN/m. O melhor resultado foi observado no ensaio 8 (milhocina 8,0%, lactose 1,0% e óleo de milho pós-fritura 7,5%) do planejamento fatorial, com 72 horas de fermentação, reduzindo a tensão superficial da água de 71 para 29 mN/m. Os melhores resultados do índice (E24) e da atividade de emulsificação (UEA) foram observados no ponto central, sendo utilizados para ambos os métodos o óleo de milho, que resultou no E24 de 2% e atividade com valores acima de 6 UAE. Os resultados obtidos demonstram o elevado potencial de C. violaceum na produção de um promissor biossurfactante.

Chromobacterium sp. from the tropics: detection and diversity of phytase activity

Phytases are a group of enzymes that catalyze phytic acid hydrolysis with release of phosphorus (P). The ability of Chromobacterium sp. to produce phytase was detected in 115 out of 118 candidate bacteria isolated from different Brazilian biomas. This is the first report revealing the genus Chromobacterium as phytase producer.

Computational analysis suggests that virulence of Chromobacterium violaceum might be linked to biofilm formation and poly-NAG biosynthesis

Groups of genes that produce exopolysaccharide with a N-acetyl-D-glucosamine monomer are in the genome of several pathogenic bacteria. Chromobacterium violaceum, an opportunistic pathogen, has the operon hmsHFR-CV2940, whose proteins can synthesize such polysaccharide. In this work, multiple alignments among proteins from bacteria that synthesize such polysaccharide were used to verify the existence of amino acids that might be critical for pathogen activity. Three-dimensional models were generated for spatial visualization of these amino acid residues. The analysis carried out showed that the protein HmsR preserves the amino acids D135, D228, Q264 and R267, considered critical for the formation of biofilms and, furthermore, that these amino acids are close to each other. The protein HmsF of C. violaceum preserves the residues D86, D87, H156 and W115. It was also shown that these residues are also close to each other in their spatial arrangement. For the proteins HmsH and CV2940 there is evidence of conservation of the residues R104 and W94, respectively. Conservation and favorable spatial location of those critical amino acids that constitute the proteins of the operon indicates that they preserve the same enzymatic function in biofilm synthesis. This is an indicator that the operon hmsHFR-CV2940 is a possible target in C. violaceum pathogenicity.

Diversity of Chromobacterium violaceum isolates from aquatic environments of state of Pará, Brazilian Amazon

The present study intended to characterize the phenotypic and genetic diversity of Brazilian isolates of Chromobacterium violaceum from aquatic environments within the Amazon region. Nineteen isolates showed morphological properties of C. violaceum and the majority grew at 44°C. Low temperatures, in contrast, showed to be inhibitory to their growth, as eleven isolates did not grow at 10ºC and nine did not produce pigmentation, clearly indicating an inhibition of their metabolism. The largest variation among isolates was observed in the citrate test (Simmons), in which 12 isolates were positive, and in the oxidation/fermentation of sucrose, with six positives isolates. Chloramphenicol, gentamicin and sulfonamides efficiently inhibited bacterial growth. Amplified products of the recA gene were digested with HindII or PstI, which produced three or four restriction fragments patterns, respectively. The combined analysis arranged the isolates into six genospecies. The higher diversity observed in Belém (genotypes C, D, E and F) may be a consequence of intense human occupation, pollution of the aquatic environment or due to the higher diversity of the environments sampled in that region. In conclusion, a high level of genetic and phenotypic diversity was observed, and four new genospecies were described.

Fatal septicemia caused by Chromobacterium violaceum in a child from Colombia

A 4-year old child living in Colombia presented with a history of fever and severe abdominal pain for four days. The patient developed pneumonia, septic shock, multiple organ failure and died on the fifth day of hospitalization. Chromobacterium violaceum was isolated from admission blood cultures and was resistant to ampicillin, cephalosporins, carbapenems and aminoglycosides.

Una niña de 4 años que vivía en Colombia presentó historia de fiebre y dolor abdominal severo por cuatro días. La paciente desarrollo neumonía, shock séptico, múltiple falla de órganos y muerte el quinto día de hospitalización. Chromobacterium violaceum fue aislado de cultivos de sangre y mostró resistencia a ampicilina, cefalosporinas, carbapenems y aminoglicosidos.

Sepsis por Chromobacterium violaceum pigmentado y no pigmentado / Sepsis caused by pigmented and no pigmented Chromobacterium violaceum

La sepsis por Chromobacterium violaceum es un cuadro clínico rara vez reportado y asociado con una elevada letalidad. Comunicamos un caso fatal de sepsis en un niño indígena venezolano con 6 años de edad, quien presentó fiebre y aumento de volumen en la región inguinal derecha y que fuera inicialmente diagnosticado como plastrón apendicular abscedado. La cirugía de apendicetomía reveló un absceso en el músculo psoas derecho, del cual se aisló una cepa pigmentada de C. violaceum, mientras que a partir de hemocultivos se aislaron cepas pigmentada y no pigmentada, simultáneamente, del mismo agente. Se administró tratamiento con imipenem y amikacina pero su condición se deterioró y falleció a los 9 días de su ingreso.

Chromobacterium violaceum sepsis is rare but associated with a high mortality rate. We report a fatal case of C. violaceum sepsis in a 6 years old Venezuelan indian boy. Clinical manifestations were fever and swelling in the right inguinal region. The initial diagnosis was an appendicular plastron. Appendicectomy was performed and during surgery a right psoas abscess was identified that resulted culture positive for pigmented C. violaceum. Blood cultures were positive for a pigmented and non pigmented C. violaceum strain. Imipenem and amikacin were administered despite of which the child died 9 days after hospital admission.

Fatal septicaemia due to Chromobacterium violaceum

Human infection caused by Chromobacterium violaceum is rare but when it occurs, it is associated with a high mortality rate. This is a report of a young adult male who presented as a surgical emergency and succumbed soon after. The most common feature of this infection is sepsis, followed by cutaneous involvement and liver abscesses. Chromobacterium infection as a differential in a case of sepsis is important for clinicians to suspect, especially in tropical countries.