Tropodithietic acid induces oxidative stress response, cell envelope biogenesis and iron uptake in Vibrio vulnificus.

The Roseobacter group is a widespread marine bacterial group, of which some species produce the broad-spectrum antibiotic tropodithietic acid (TDA). A mode of action for TDA has previously been proposed in Escherichia coli, but little is known about its effect on non-producing marine bacteria at in situ concentrations. The purpose of this study was to investigate how a sub-lethal level of TDA affects Vibrio vulnificus at different time points (30 and 60 min) using a transcriptomic approach. Exposure to TDA for as little as 30 min resulted in the differential expression of genes associated with cell regeneration, including the up-regulation of those involved in biogenesis of the cell envelope. Defence mechanisms including oxidative stress defence proteins and iron uptake systems were also up-regulated in response to TDA, while motility-related genes were down-regulated. Gene expression data and scanning electron microscopy imaging revealed a switch to a biofilm phenotype in the presence of TDA. Our study shows that a low concentration of this antibiotic triggers a defence response to reactive oxygen species and iron depletion in V. vulnificus, which indicates that the mode of action of TDA is likely more complex in this bacterium than what is known for E. coli.

Tetanus associated with road accidents in the infectious diseases department of Point G University Hospital, Bamako, Mali.

The aim of this study was to describe the epidemiological, clinical, and prognostic aspects of tetanus associated with road accidents and to make recommendations. This observational study collected retrospective clinical data over a 9-year period about adults admitted for trismus and/or generalized or localized paroxysm after a road accident. The study included 25 patients, accounting for 22.12 % of all tetanus cases. Men were massively overrepresented (sex-ratio M/F: 24/1). The median age was 34 ± 8 years. In all, vaccination status was unknown for 4 patients and known to be negative for 21. Immunoprophylaxis was nonexistent in all cases. The generalized clinical form was dominant (96 %). Severity reached level III for 12 % of patients. The points of entry included open leg fractures (4 cases), head wounds (2), mucocutaneous wounds (14), and muscle contusions (5). The mean time to referral for tetanus was 8 ± 7 days, and the median hospital stay 9.08 ± 11 days. Patients were mostly residents of urban (56 %) and suburban areas (28 %) [P = 0.04]. Two cases were complicated by severe malaria. The mortality rate was 60 %, and 52 % of the deaths occurred within the first 72 hours after hospitalization. It is essential to promote serum therapy and tetanus immunization for patients after road accidents. Increasing the awareness of traditional healers of these treatments deserves consideration.

Global occurrence and heterogeneity of the Roseobacter-clade species Ruegeria mobilis.

Tropodithietic acid (TDA)-producing Ruegeria mobilis strains of the Roseobacter clade have primarily been isolated from marine aquaculture and have probiotic potential due to inhibition of fish pathogens. We hypothesized that TDA producers with additional novel features are present in the oceanic environment. We isolated 42 TDA-producing R. mobilis strains during a global marine research cruise. While highly similar on the 16S ribosomal RNA gene level (99-100% identity), the strains separated into four sub-clusters in a multilocus sequence analysis. They were further differentiated to the strain level by average nucleotide identity using pairwise genome comparison. The four sub-clusters could not be associated with a specific environmental niche, however, correlated with the pattern of sub-typing using co-isolated phages, the number of prophages in the genomes and the distribution in ocean provinces. Major genomic differences within the sub-clusters include prophages and toxin-antitoxin systems. In general, the genome of R. mobilis revealed adaptation to a particle-associated life style and querying TARA ocean data confirmed that R. mobilis is more abundant in the particle-associated fraction than in the free-living fraction occurring in 40% and 6% of the samples, respectively. Our data and the TARA data, although lacking sufficient data from the polar regions, demonstrate that R. mobilis is a globally distributed marine bacterial species found primarily in the upper open oceans. It has preserved key phenotypic behaviors such as the production of TDA, but contains diverse sub-clusters, which could provide new capabilities for utilization in aquaculture.

Phaeobacter inhibens from the Roseobacter clade has an environmental niche as a surface colonizer in harbors.

Phaeobacter inhibens belongs to the marine Roseobacter clade and is important as a carbon and sulfur metabolizer, a biofilm former and producer of the antibiotic tropodithietic acid (TDA). The majority of cultured strains have been isolated from marine aquaculture sites, however, their niche in the environment is to date unknown. Here, we report on the repeated isolation of Phaeobacter inhibens strains from a marine environment (harbors) not related to aquaculture. Based on phenotype and 16S rRNA gene sequence similarity, a total of 64 P. inhibens strains were identified from 35 samples (eukaryotic organisms or biofilms on inert surfaces) in Jyllinge Harbor during late summer and autumn, but not during winter and spring in 2009, 2011, and 2012. P. inhibens strains were also isolated from biofilms at three other Danish harbors (in 2012), but not from the surrounding seawater. Ten of the 14 samples from which P. inhibens was cultured contained bryozoans. DNA was extracted (in 2012) from 55 out of 74 Jyllinge Harbor samples, and 35 were positive for Phaeobacter using a genus-specific PCR. P. inhibens strains were isolated from nine of these samples. DNA and RNA were isolated from 13 random samples and used for amplification of 16S rRNA. P. inhibens was detected in five of these samples, all of which were biofilm samples, by pyrotag-sequencing at a prevalence of 0.02-0.68% of the prokaryotic community. The results indicated that P. inhibens had a niche in biofilms of fouled surfaces in harbor areas and that the population followed a seasonal fluctuation.

[Epidemiological, clinical and evolving HIV-positive patients referred to the University Hospital of Point G, Bamako, Mali]. / Profil épidémioclinique et évolutif de patients VIH positif, référés au CHU du Point G, Bamako, Mali.

We conduct a longitudinal descriptive study in the department of infectious diseases to CHU of Point G during 18 months. It concerned adult patients referred from another care center. All the patients underwent systematic clinical examination and complementary exploration. Our sample was 352 HIV+ patients, with a mean age of 37.8 ± 9.8 years and a sex ratio (M/F)=0.94 shared among patients receiving ARV treatment (ART-s) and not (n-ART). Delay of reference was 5 ± 4.4 days. All patients benefited from clinical and paraclinical examinations. In both groups patients were mostly from level II. On admission, 132 cases were ART-s (38%). The main reasons for consultation were mainly fever [87.9%, p <0.05] and vomiting [17.4%, p =0.005] in the ART-s. Cough (p=0.9), and diarrhoea (p=0.5] were most noted in the n-TARV no statistically significant (no SS). Other reference reasons were similar in the 2 groups: headache (p=0.4), dyspnea (p=0.1). Selected diagnoses were dominated by tuberculosis (p=0.6) for n-ART no SS. Nontuberculosis infectious pneumonia (p=0.8) and cerebral toxoplasmosis (p=0.8) were comparable in the two groups. Severe systemic bacterial infections occurred more noted in the n-TARV (p=0.7). Malaria has been the main non-AIDS defining disease in the n-ART [-p=0.07] no SS. Patients were seen to late stage a corollary of a more collapsed of immunity in n-ART group [93.3%, p <0.05]. The fatality rate was similar in both groups (43.2%). Pathological factors were mainly tuberculosis (p=0.3) no SS. The factors involved significantly in TARV-s were non-tuberculosis bacterial pneumonia (p=0.001). The hospital mortality of HIV and AIDS is still important. Despite free ARVs and the large number of support center, the delay in diagnosis is a key as well as the lack of monitoring of patients factor.

[Human rabies in Abidjan (Côte d'Ivoire): recent cases]. / Rage humaine à Abidjan (Côte d'Ivoire): nouvelles observations.

OBJECTIVE: To present epidemiological and clinical aspects of human rabies in a hospital center. METHOD: We analyzed medical records of cases of rabies in humans treated at the infectious disease department of the Treichville University Hospital Center from January 2005 through December 2009. RESULTS: Seven cases of human rabies were reported during those five years, four in teenagers and three in adults. Five of the cases involved bites by stray dogs whose vaccine status was unknown. No patient had had a pre-exposure prophylactic vaccination, and only four post-exposure prophylaxis, all incomplete. All of the patients developed furious rabies and fever 21 to 96 days (mean: 47.7) after the dog bite, when the wounds had healed and scars formed. Death occurred 4 to 10 days after the onset of symptoms (mean: 4.7). Relatives refused autopsies in all cases. CONCLUSION: It is indispensable to increase population awareness of prevention by vaccination against human rabies, reduce the population of stray dogs, and promote mass vaccination of dogs in the Ivory Coast.

Inactivation of Vibrio anguillarum by attached and planktonic Roseobacter cells.

The purpose of the present study was to investigate the inhibition of Vibrio by Roseobacter in a combined liquid-surface system. Exposure of Vibrio anguillarum to surface-attached roseobacters (10(7) CFU/cm(2)) resulted in significant reduction or complete killing of the pathogen inoculated at 10(2) to 10(4) CFU/ml. The effect was likely associated with the production of tropodithietic acid (TDA), as a TDA-negative mutant did not affect survival or growth of V. anguillarum.

[AIDS related Kaposi's disease in Hospital area in Bamako]. / La Maladie de Kaposi au cours du VIH/Sida en milieu hospitalier de Bamako.

The goal of this prospective work were to describe the clinical, therapeutic and evolutionary aspects of Kaposi's disease occurring during AIDS in the infectious diseases service from October 1, 2004 to September 30, 2005. The diagnosis of the infection by the HIV was based on the positivity of serology with 2 fast tests. That of the Kaposi's disease was based on the clinical aspect and /or histological of the lesions. On these 2189 patients, 37 presented the Kaposi's disease that means a prevalence of 1.6%. They were 17 men and 20 women average age 39.5 years and heterosexuals in 97.30 % of the cases. Kaposi's disease limited on the skin and mucous were most represented within (48.65 %), followed by the skin limited (43.24 %) and mucous localization (8.11%). Papulo-nodulare feature was the major clinical founded to the physical examination in 54.05 %. The rate of average CD4 was 76 cellules/mm3 with the extreme one going from 1 to 512 cellules/mm3. It was favorable at 14 (43.75%) of the 32 patients having profited from antiretroviral treatment. The Kaposi's disease during the AIDS is relatively frequent with the service of the infectious diseases and the prognosis remains severe. However the antiretroviral therapy can improve the prognosis of the skin limited forms.

La Maladie de Kaposi au cours du VIH/Sida en milieu hospitalier de Bamako

Le but de ce travail prospectif etait de decrire les aspects clinique; therapeutique et evolutif de la maladie de Kaposi associee au VIH/SIDA au service des Maladies Infectieuses du 1er octobre 2004 au 30 septembre 2005. Le diagnostic de l'infection par le VIH etait base sur la positivite de la serologie a 2 tests rapides. Celui de la maladie de Kaposi etait base sur l'aspect clinique et /ou histologique des lesions. Sur ces 2189 patients; 37 ont presente la maladie de Kapozi soit une prevalence de 1;6. Il s'agissait de 17 hommes et 20 femmes d'age moyen de 39;5 ans et heterosexuels dans 97;30 des cas. La localisation cutaneo-muqueuse etait la plus frequente (48;65 ) suivie de la localisation cutanee (43;24 ) et muqueuse (8;11). L'aspect clinique le plus predominant a ete papulonodulaire dans 54;05 des cas. Le taux de CD4 moyen etait de 76 cellules/mm3 avec des extremes allant de 1 a 512 cellules/mm3. Elle a ete favorable chez 14 (43;75) des 32 patients ayant beneficie d'un traitement antiretroviral. La maladie de Kapozi au cours du VIH/SIDA est relativement frequente au service des Maladies Infectieuses et le pronostic reste severe. Toutefois les anti-retroviraux peuvent ameliorer le pronostic des formes localisees a la peau. Mots cles : Prevalence; Maladie Kaposi; VIH/SIDA; Mali