- Volume 65, Issue 12, 2016
Volume 65, Issue 12, 2016
- Pathogenicity and Virulence/Host Response
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The exploration of risk factors of concurrent bacteraemia in patients critically ill with severe dengue
We investigated the clinical features of intensive care unit (ICU) patients with concomitant severe dengue infection and bacteraemia to identify risk factors for this comorbidity. The records of all ICU dengue patients admitted during the period of 31 July–30 November 2015 were reviewed. Patients with ‘concurrent bacteremia’ (positive bacterial blood culture within 72 h of ICU admission) were identified. ICU admission was required for 142 patients, of which 22 (15.5 %) had concurrent bacteraemia. Species of the genus Streptococcus was the most common pathogens, followed by Escherichia coli then species of the genus Staphylococcus. Patients with a severe dengue infection and bacteraemia had higher APACHE II and TISS scores, C-reactive protein (CRP) levels and leukocyte counts, positive fluid balances, longer activated partial thromboplastin times (APTTs), higher lactate levels and more kidney failure, but controls (severe dengue patients without bacteraemia) had higher Glasgow Coma Scale (GCS) scores, higher albumin levels and more abdominal pain (all P<0.05). Patients with bacteraemia had a higher mortality rate than did ontrols (40.9 vs 18.3 %; P=0.018). Multiple logistic regression analysis showed that bacteraemia was significantly positively associated with the following independent predictors: higher CRP levels [adjusted odds ratio (aOR): 1.026; 95 % confidence interval (CI): 1.008–1.044; P=0.005], and longer APTTs (aOR: 1.034; 95 CI: 1.004–1.065; P=0.027). Concurrent bacteraemia is not uncommon in severe dengue patients in the ICU, and it is associated with high mortality. Higher CRP levels and longer APTTs were two independent risk factors associated with bacteraemia.
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- Prevention and Therapy
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Microbiological sentinel events at a neurological hospital: a retrospective cohort study
The purpose of this study is to describe the epidemiological surveillance of microbiological sentinel events (SEs) carried out between 2012 and 2014 at the Neurological Hospital Carlo Besta, Milano, Italy. The setting is inpatient care with multidrug-resistant infections. The aim of the procedure is to formalize the management mode, reporting and transmission of SEs. Categorical variables were described by counts and percentages, as mean and sd or median and interquartile range. The incidence rates of SE were calculated per 1000 patient-days and for 100 admissions using Poisson distribution. The incidence rate of isolation for 1000 patient-days varies from a minimum of 0.52 (95 % confidence interval, 0.23–1.15) for the second quarter of 2014 to a maximum value of 4.16 (95 % confidence interval, 3.20–5.40) for the first quarter of 2013. A decrease followed from the third quarter of 2013 that remained constant in 2014, reaching values similar to those of 2012. Preventive actions and their effectiveness on Acinetobacter baumannii, the primary cause in our division of multidrug-resistant infections in 2012, have ensured a reduction of the incidence of the same; preventive actions and their effectiveness allowed us to intercept microbiological SE and trigger appropriate precautionary behaviour and isolation. Surveillance of healthcare-associated infections is fundamental in understanding the sources that are contributing to the growing reservoir within hospital communities.
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Development, validation and implementation of a quadruplex real-time PCR assay for identification of potentially toxigenic corynebacteria
More LessToxigenic corynebacteria are uncommon in the UK; however, laboratory confirmation by the national reference laboratory can inform public health action according to national guidelines. Standard phenotypic tests for identification and toxin expression of isolates can take from ≥24 to ≥48 h from receipt. To decrease the time to result, a real-time PCR (qPCR) assay was developed for confirmation of both identification of Corynebacterium diphtheriae and Corynebacterium ulcerans/Corynebacterium pseudotuberculosis and detection of the diphtheria toxin gene. Target genes were the RNA polymerase β-subunit-encoding gene (rpoB) and A-subunit of the diphtheria toxin gene (tox). Green fluorescent protein DNA (gfp) was used as an internal process control. qPCR results were obtained within 3 to 4 h after receipt of isolate. The assay was validated according to published guidelines and demonstrated high diagnostic sensitivity (100 %), high specificity (98–100 %) and positive and negative predictive values of 91 to 100 % and 100 %, respectively, compared to both block-based PCR and the Elek test, together with a greatly reduced time from isolate receipt to reporting. Limitations of the qPCR assay were the inability to distinguish between C. ulcerans and C. pseudotuberculosis and that the presence of the toxin gene as demonstrated by qPCR may not always predict toxin expression. Thus, confirmation of expression of diphtheria toxin is always sought using the phenotypic Elek test. The new qPCR assay was formally introduced as the front-line test for putative toxigenic corynebacteria to inform public health action in England and Wales on 1 April 2014.
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Inhibition of quorum-sensing-controlled virulence factors of Pseudomonas aeruginosa by Murraya koenigii essential oil: a study in a Caenorhabditis elegans infectious model
More LessThe global emergence of antibiotic-resistant strains of Pseudomonas aeruginosa poses a major threat in both hospital environments and the community. P. aeruginosa is an opportunistic human pathogen, and it also infects a wide range of model organisms including the nematode Caenorhabditis elegans. Quorum sensing (QS) mediates cell-to-cell communication in bacteria and has an important role in regulating virulence genes, antibiotic resistance and biofilm formation, which are crucial for establishment of the infection. Expression of many virulence factors such as pyocyanin and proteases in P. aeruginosa is under the control of the QS system, and are mediated by small molecules such as acyl homoserine lactones. Thus, interfering with the QS system would provide alternative ways of controlling the pathogenicity. Murraya koenigii is a medicinal plant widely used in India. The present study investigated the in vivo inhibitory activity of M. koenigii essential oil (EO) on QS-controlled virulence factors of P. aeruginosa PAO1 using C. elegans. M. koenigii EO significantly inhibited the pyocyanin production and staphylolytic LasA activity of P. aeruginosa PAO1. As compared to the control group with 100 % killing of C. elegans, M. koenigii EO was able to rescue an average of 60 % of C. elegans from death due to the toxic effect of P. aeruginosa. Thus, the present study suggests the anti-QS potential of M. koenigii EO which therefore can be considered as a future therapeutic agent for management of P. aeruginosa-mediated infections.
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Antimicrobial susceptibility to azithromycin among Salmonella enterica Typhi and Paratyphi A isolates from India
More LessDecreased ciprofloxacin susceptibility (DCS) and multidrug resistance in typhoidal Salmonella isolates in areas of endemicity are significant therapeutic problems. Guidelines for azithromycin disc diffusion and MIC interpretive criteria for Salmonella enterica serovar Typhi were published recently by the Clinical and Laboratory Standards Institute in 2015. We investigated the antimicrobial susceptibility pattern of azithromycin in 100 isolates of Salmonella Typhi (n=80), Paratyphi A (n=18) and B (n=2) recovered from bloodstream infections from January 2013 to December 2015. Zone sizes were extrapolated against MIC values, and a scatter plot was constructed. The azithromycin MICs by Etest ranged from 2 to 16 µg ml−1, while the disc diffusion diameters were from 13 to 22 mm. We observed that the margin of the zone of inhibition around the azithromycin disc may not be very clear and therefore difficult to interpret and that there was wide variation in the zone sizes for the same MIC value in both serovars. DCS was observed in 85 % of Salmonella Typhi recovered (68/80) and in 15/18 (83.3 %) Paratyphi A isolates. Judicious use of azithromycin is advocated as an alternative oral agent in endemic areas where DCS is common.
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- Correspondence
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Volumes and issues
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Volume 73 (2024)
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Volume 72 (2023 - 2024)
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Volume 71 (2022)
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Volume 70 (2021)
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Volume 69 (2020)
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Volume 68 (2019)
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Volume 67 (2018)
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Volume 66 (2017)
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Volume 65 (2016)
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Volume 64 (2015)
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Volume 63 (2014)
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Volume 62 (2013)
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Volume 61 (2012)
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Volume 60 (2011)
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Volume 59 (2010)
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Volume 58 (2009)
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Volume 57 (2008)
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Volume 56 (2007)
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Volume 55 (2006)
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Volume 54 (2005)
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Volume 53 (2004)
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Volume 52 (2003)
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Volume 51 (2002)
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Volume 50 (2001)
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Volume 49 (2000)
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Volume 48 (1999)
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Volume 47 (1998)
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Volume 46 (1997)
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Volume 45 (1996)
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Volume 44 (1996)
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Volume 43 (1995)
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Volume 42 (1995)
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Volume 41 (1994)
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Volume 40 (1994)
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Volume 39 (1993)
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Volume 38 (1993)
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Volume 37 (1992)
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Volume 36 (1992)
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Volume 35 (1991)
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Volume 34 (1991)
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Volume 33 (1990)
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Volume 32 (1990)
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Volume 31 (1990)
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Volume 30 (1989)
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Volume 29 (1989)
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Volume 28 (1989)
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Volume 27 (1988)
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Volume 26 (1988)
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Volume 25 (1988)
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Volume 24 (1987)
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Volume 23 (1987)
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Volume 22 (1986)
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Volume 21 (1986)
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Volume 20 (1985)
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Volume 19 (1985)
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Volume 18 (1984)
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Volume 17 (1984)
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Volume 16 (1983)
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Volume 15 (1982)
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Volume 14 (1981)
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Volume 13 (1980)
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Volume 12 (1979)
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Volume 11 (1978)
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Volume 10 (1977)
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Volume 9 (1976)
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Volume 8 (1975)
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Volume 7 (1974)
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Volume 6 (1973)
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Volume 5 (1972)
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Volume 4 (1971)
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Volume 3 (1970)
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Volume 2 (1969)
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Volume 1 (1968)