Group B Streptococcal Colonization in 160 Mother-Baby Pairs: A Prospective Cohort Study

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Serratia marcescens in a neonatal intensive care unit: two long-term multiclone outbreaks in a 10-year observational study

We investigated two consecutive Serratia marcescens (S. marcescens) outbreaks which occurred in a neonatal intensive care unit (NICU) of a tertiary level hospital in North Italy in a period of 10 years (January 2003-December 2012). Risk factors associated with S. marcescens acquisition were evaluated by a retrospective case-control study. A total of 21,011 clinical samples was examined: S. marcescens occurred in 127 neonates: 43 developed infection and 3 died. Seven clusters were recorded due to 12 unrelated clones which persisted for years in the ward, although no environmental source was found. The main epidemic clone A sustaining the first cluster in 2003 reappeared in 2010 as an extended spectrum ?-lactamase (ESBL)-producing strain and supporting the second epidemic. Birth weight, gestational age, use of invasive devices and length of stay in the ward were significantly related to S. marcescens acquisition. The opening of a new ward for non-intensive care-requiring neonates, strict adherence to alcoholic hand disinfection, the timely identification and isolation of infected and colonized neonates assisted in containing the epidemics. Genotyping was effective in tracing the evolution and dynamics of the clones demonstrating their long-term persistence in the ward

Impact of Pre-Analytical Time on the Recovery of Pathogens from Blood Cultures: Results from a Large Retrospective Survey

Prompt identification of bloodstream pathogens is essential for optimal management of patients. Significant changes in analytical methods have improved the turnaround time for laboratory diagnosis. Less attention has been paid to the time elapsing from blood collection to incubation and to its potential effect on recovery of pathogens. We evaluated the performance of blood cultures collected under typical hospital conditions in relation to the length of their pre-analytical time. We carried out a large retrospective study including 50,955 blood cultures collected, over a 30-month period, from 7,035 adult septic patients. Cultures were accepted by the laboratory only during opening time (Mon-Fri: 8am\ub14pm; Sat: 8am\ub12pm). Samples collected outside laboratory hours were stored at room temperature at clinical wards. All cultures were processed by automated culture systems. Day and time of blood collection and of culture incubation were known for all samples. A maximum pre-analytical interval of 2 hours is recommended by guidelines. When the laboratory was open, 57% of cultures were processed within 2 h. When the laboratory was closed, 4.9% of cultures were processed within 2 h (P<0.001). Samples collected when the laboratory was closed showed pre-analytical times significantly longer than those collected when laboratory was open (median time: 13 h and 1 h, respectively, P<0.001). The prevalence of positive cultures was significantly lower for samples collected when the laboratory was closed compared to open (11% vs 13%, P<0.001). The probability of a positive result decreased of 16% when the laboratory was closed (OR:0.84; 95%CI:0.80\ub10.89, P<0.001). Further, each hour elapsed from blood collection to incubation resulted associated with a decrease of 0.3% (OR:0.997; 95%CI:0.994\ub10.999, P<0.001) in the probability of a positive result. Delayed insertions of cultures into automated systems was associated with lower detection rates, with potentially important consequences for patients. In each hospital setting the logistic factors able to shorten pre-analytical time should be carefully investigated and specifically targeted

Pulmonary disease caused by Mycobacterium marseillense, Italy

Mycobacteriummarseillense was recently described as a new species belonging to the Mycobacterium avium complex (MAC).We describe a case of pulmonary disease caused by M. marseillense in an immunocompetent patient. All strains isolated from the patient were preliminarily identified as M. intracellulare; however, a retrospective molecular analysis corrected the identification to M. marseillense

Severe pneumonia caused by Legionella pneumophila serogroup 11, Italy.

Legionella pneumophila serogroups (SGs) 1–16 cause pneumonia in humans. Although SG 1 is the serogroup most commonly associated with disease, we report a case of community-acquired legionellosis caused by SG 11

Improvement of Legionnaires' disease diagnosis using real-time PCR assay: a retrospective analysis, Italy, 2010 to 2015

AimTo evaluate real-time PCR as a diagnostic method for Legionnaires' disease (LD). Detection of Legionella DNA is among the laboratory criteria of a probable LD case, according to the European Centre for Disease Prevention and Control, although the utility and advantages, as compared to culture, are widely recognised.MethodsTwo independent laboratories, one using an in-house and the other a commercial real-time PCR assay, analysed 354 respiratory samples from 311 patients hospitalised with pneumonia between 2010-15. The real-time PCR reliability was compared with that of culture and urinary antigen tests (UAT). Concordance, specificity, sensitivity and positive and negative predictive values (PPV and NPV, respectively) were calculated.ResultsOverall PCR detected eight additional LD cases, six of which were due to Legionella pneumophila (Lp) non-serogroup 1. The two real-time PCR assays were concordant in 99.4% of the samples. Considering in-house real-time PCR as the reference method, specificity of culture and UAT was 100% and 97.9% (95% CI: 96.2-99.6), while the sensitivity was 63.6% (95%CI: 58.6-68.6) and 77.8% (95% CI: 72.9-82.7). PPV and NPV for culture were 100% and 93.7% (95% CI: 91.2-96.3). PPV and NPV for UAT were 87.5% (95% CI: 83.6-91.4) and 95.8% (95% CI: 93.5-98.2).ConclusionRegardless of the real-time PCR assay used, it was possible to diagnose LD cases with higher sensitivity than using culture or UAT. These data encourage the adoption of PCR as routine laboratory testing to diagnose LD and such methods should be eligible to define a confirmed LD case

The new phylogenesis of the genus Mycobacterium

Abstract Phylogenetic knowledge of the genus Mycobacterium is based on comparative analysis of their genetic sequences. The 16S rRNA has remained for many years the only target of such analyses, but in the last few years, other housekeeping genes have been investigated and the phylogeny based on their concatenated sequences become a standard. It is now clear that the robustness of the phylogenetic analysis is strictly related to the size of the genomic target used. Whole genome sequencing (WGS) is nowadays becoming widely accessible and comparatively cheap. It was decided, therefore, to use this approach to reconstruct the ultimate phylogeny of the genus Mycobacterium . Over 50 types of strains of the same number of species of Mycobacterium were sequenced using the Illumina HiSeq platform. The majority of the strains of which the whole sequence was already available in GenBank were excluded from this panel with the aim of maximizing the number of the species with genome available. Following assembling and annotation with proper software, the phylogenetic analysis was conducted with PhyloPhlAn and the pan-genome analysis pipeline. The phylogenetic three which emerged was characterized by a clear-cut distinction of slowly and rapidly growing species with the latter being more ancestral. The species of the Mycobacterium terrae complex occupied an intermediate position between rapid and slow growers. Most of the species revealed clearly related and occupied specific phylogenetic branches. Thanks to the WGS technology, the genus Mycobacterium is finally approaching its definitive location

Comparison of three assays currently used for diagnosis of legionellosis

The laboratory diagnosis of Legionnaires’ disease is extremely complex due to the difficulty of isolating and identifying the etiological agent in a short time and also for the frequent late appearance of antibodies. For this reason it should use not only the cultures but also other diagnostic tests such as urinary antigen and antibody research. Our study evaluated the performance of these methods.We calculated the positive predictive value (PPV) and negative predictive value (NPV), sensitivity and specificity of each test

Evaluation of a rapid immunochromatographic assay for the detection and identification of Legionella spp. strains isolated from cultures

The Legionnaires’ disease is a major issue in the healthcare because it ranks among the emerging infectious diseases in our country, particularly those caused by Legionella pneumophila serogroup 1. The severity of the infection is related to several factors including the virulence of the bacterium and the immune status of patient. Since the clinical diagnosis of Legionella infections or pneumonia with different etiology is extremely difficult, the use of new diagnostic techniques in rapid identification plays a key role. The aim of our study was to evaluate the performance of a new immunochromatographic assay can detect and identify strains of Legionella spp. from the cultures