A polymorphism in human CD1A is associated with susceptibility to tuberculosis

CD1 proteins are antigen-presenting molecules that evolved to present lipids rather than peptides to T cells. However, unlike major histocompatibility complex genes, CD1 genes show low rates of polymorphism and have not been clearly associated with human disease. We report that an intronic polymorphism in CD1A (rs411089) is associated with susceptibility to tuberculosis in two cohorts of Vietnamese adults (combined cohort odds ratio 1.78; 95% confidence interval: 1.24-2.57; P=0.001). These data strengthen the hypothesis that CD1A-mediated lipid antigen presentation is important for controlling tuberculosis in humans. Copyright © 2014 Macmillan Publishers Limited

Minimum inhibitory concentrations of commercial essential oils against common chicken pathogenic bacteria and their relationship with antibiotic resistance

Aims We investigated the antibacterial effect of seven essential oils (EOs) and one EO-containing liquid phytogenic solution marketed for poultry and pigs (&lsquo;Product A&rsquo;) on chicken pathogens, as well as the relationship between minimum inhibitory concentration (MIC) in EOs and antibiotics commonly administered to chicken flocks in the Mekong Delta (Vietnam). Methods and Results Micellar extracts from oregano (Origanum vulgare), cajeput (Melaleuca leucadendra), garlic (Allium sativum), black pepper (Piper nigrum), peppermint (Mentha&nbsp;&times;&nbsp;piperita&nbsp;L.), tea tree (Melaleuca alternifolia), cinnamon (Cinnamomum zeylanicum) EOs and Product A were investigated for their MIC against&nbsp;Avibacterium endocarditidis&nbsp;(N&nbsp;=&nbsp;10),&nbsp;Pasteurella multocida&nbsp;(N&nbsp;=&nbsp;7),&nbsp;Ornitobacterium rhinotracheale&nbsp;(ORT) (N&nbsp;=&nbsp;10),&nbsp;Escherichia coli&nbsp;(N&nbsp;=&nbsp;10) and&nbsp;Gallibacterium anatis&nbsp;(N&nbsp;=&nbsp;10). Cinnamon EO had the lowest median MIC across strains (median 0.5&nbsp;mg/ml [IQR, interquartile range 0.3&ndash;2.0&nbsp;mg/ml]), followed by Product A (3.8&nbsp;mg/ml [1.9&ndash;3.8&nbsp;mg/ml]), oregano EO (30.4&nbsp;mg/ml [7.6&ndash;60.8&nbsp;mg/ml]) and garlic 63.1&nbsp;mg/ml [3.9 to &gt;505.0&nbsp;mg/ml]. Peppermint, tea tree, cajeput and pepper EOs had all MIC &ge;219&nbsp;mg/ml. In addition, we determined the MIC of the 12&nbsp;most commonly used antibiotics in chicken flocks in the area. After accounting for pathogen species, we found an independent, statistically significant (p&nbsp;&lt;&nbsp;0.05) positive correlation between MIC of 10 of 28 (35.7%) pairs of EOs. For 67/96 (69.8%) combinations of EOs and antibiotics, the MICs were correlated. Of all antibiotics, doxycycline was positively associated with the highest number of EOs (peppermint, tea tree, black pepper and cajeput, all&nbsp;p&nbsp;&lt;&nbsp;0.05). For cinnamon, the MICs were negatively correlated with the MICs of 11/12 antimicrobial tested (all except colistin). Conclusions Increases in MIC of antibiotics generally correlates with increased tolerance to EOs. For cinnamon EO, however, the opposite was observed. Significance and Impact of the Study Our results suggest increased antibacterial effects of EOs on multi-drug resistant pathogens; cinnamon EO was particularly effective against bacterial poultry pathogens.</p

Characterizing antimicrobial resistance in chicken pathogens: a step towards improved antimicrobial stewardship in poultry production in Vietnam

In the Mekong Delta of Vietnam, farmers use large quantities of antimicrobials to raise small-scale chicken flocks, often including active ingredients regarded of "critical importance'" by the World Health Organization. Due to limitations in laboratory capacity, the choice of antimicrobials normally does not follow any empirical criteria of effectiveness. The aim of this study was to highlight non-critically important antimicrobials against which chicken pathogens are likely to be susceptible as a basis for treatment guidelines. Microtiter broth dilution method was performed to determine the minimal inhibitory concentration (MIC) of 12 commonly used antimicrobials for 58 isolates, including Ornithobacterium rhinotracheale (ORT) (n = 22), Gallibacterium anatis (n = 19), and Avibacterium endocarditidis (n = 17). Unfortunately, internationally accepted breakpoints for resistance in these organisms do not exist. We drew tentative epidemiological cut-offs (TECOFFs) for those antimicrobial-pathogen combinations where MIC distributions suggested the presence of a distinct non-wild-type population. Based on the observed results, doxycycline would be the drug of choice for A.endocarditidis (11.8% presumptive non-wild type) and G. anatis infections (5.3% presumptive non-wild type). A total of 13.6% ORT isolates were non-wild type with regards to oxytetracycline, making it the drug of choice against this pathogen. This study illustrates the challenges in interpreting susceptibility testing results and the need to establish internationally accepted breakpoints for veterinary pathogens

Antimicrobial residues, non-typhoidal Salmonella, Vibrio spp. and associated microbiological hazards in retail shrimps purchased in Ho Chi Minh city (Vietnam)

We investigated antimicrobial residues, non-typhoidal Salmonella (NTS), Vibrio spp. and their associated antimicrobial resistance (AMR), in shrimps locally purchased in Ho Chi Minh City (Vietnam). In addition, we investigated the relationship between AMR in NTS, Vibrio spp. and antimicrobial residue in the same sample. A total of 40 samples of shrimp heads/shells from different retail sources was cultured using ISO 6579-1:2017 (NTS) and ISO/TS 21872-1:2007 (Vibrio spp.). Phenotypic antimicrobial susceptibility was investigated using Vitek (NTS, 34 antimicrobials) and disk diffusion (Vibrio spp., 12 antimicrobials). A total of 9 (22.5%) samples contained antimicrobial residue, including tetracyclines, fluoroquinolones, sulfonamides and macrolides (in 7.5%, 7.5%, 2.5% and 2.5% of samples, respectively). Shrimp samples from supermarkets had a higher prevalence of antimicrobial residue than those purchased in street markets (50% vs. 13.3%) (p = 0.049). A total of 30 (75%) samples were contaminated with NTS. All samples contained Vibrio spp., with V. parahaemolyticus being most common (87.5% samples). A total of 58.9% NTS isolates were multidrug resistant. With regards to the highest priority, critically important antimicrobials, the highest resistance corresponded to quinolones (14.4-47.8%), followed by 3rd and 4th generation cephalosporins (3.3-7.8%). Vibrio spp. isolates were characterised by their high resistance against ampicillin (82.7%) and 3rd generation cephalosporins (8.3-16.5%). Extended Spectrum Beta-Lactamase (ESBL) activity was detected in 28.1% V. parahaemolyticus isolates. Half of ESBL-positive V. parahaemolyticus strains harboured bla CTX-M1. We found an association between the presence of residues and the number of resistances for NTS (p = 0.075) and Vibrio spp. isolates (p = 0.093) from the same sample. These findings suggest that the presence of residues may contribute to the selection of AMR in foodborne pathogens in shrimps. Authorities should strengthen policies aiming at restricting inappropriate antimicrobial usage in shrimp farming, and step up monitoring of antimicrobial residues and food-borne pathogens at retail in Vietnam

Intensified antituberculosis therapy in adults with tuberculous meningitis

BACKGROUND: Tuberculous meningitis is often lethal. Early antituberculosis treatment and adjunctive treatment with glucocorticoids improve survival, but nearly one third of patients with the condition still die. We hypothesized that intensified antituberculosis treatment would enhance the killing of intracerebral Mycobacterium tuberculosis organisms and decrease the rate of death among patients. METHODS: We performed a randomized, double-blind, placebo-controlled trial involving human immunodeficiency virus (HIV)–infected adults and HIV-uninfected adults with a clinical diagnosis of tuberculous meningitis who were admitted to one of two Vietnamese hospitals. We compared a standard, 9-month antituberculosis regimen (which included 10 mg of rifampin per kilogram of body weight per day) with an intensified regimen that included higher-dose rifampin (15 mg per kilogram per day) and levofloxacin (20 mg per kilogram per day) for the first 8 weeks of treatment. The primary outcome was death by 9 months after randomization. RESULTS: A total of 817 patients (349 of whom were HIV-infected) were enrolled; 409 were randomly assigned to receive the standard regimen, and 408 were assigned to receive intensified treatment. During the 9 months of follow-up, 113 patients in the intensified-treatment group and 114 patients in the standard-treatment group died (hazard ratio, 0.94; 95% confidence interval, 0.73 to 1.22; P=0.66). There was no evidence of a significant differential effect of intensified treatment in the overall population or in any of the subgroups, with the possible exception of patients infected with isoniazid-resistant M. tuberculosis. There were also no significant differences in secondary outcomes between the treatment groups. The overall number of adverse events leading to treatment interruption did not differ significantly between the treatment groups (64 events in the standard-treatment group and 95 events in the intensified-treatment group, P=0.08). CONCLUSIONS: Intensified antituberculosis treatment was not associated with a higher rate of survival among patients with tuberculous meningitis than standard treatment. (Funded by the Wellcome Trust and the Li Ka Shing Foundation; Current Controlled Trials number, ISRCTN61649292. opens in new tab.)</p