Mafalda Sousa-Uva

Effect of long-term laboratory propagation on Chlamydia trachomatis genome dynamics

It is assumed that bacterial strains maintained in the laboratory for long time shape their genome in a different fashion from the nature-circulating strains. Here, we analyzed the impact of long-term in vitro propagation on the genome of the obligate intracellular pathogen Chlamydia trachomatis. We fully-sequenced the genome of a historical prototype strain (L2/434/Bu) and a clinical isolate (E/CS88), before and after one-year of serial in vitro passaging (up to 3500 bacterial generations). We observed a slow adaptation of C. trachomatis to the in vitro environment, which was essentially governed by four mutations for L2/434/Bu and solely one mutation for E/CS88, corresponding to estimated mutation rates from 3.84 × 10(-10) to 1.10 × 10(-9) mutations per base pair per generation. In a speculative basis, the mutations likely conferred selective advantage as: (i) mathematical modeling showed that selective advantage is mandatory for frequency increase of a mutated clone; (ii) transversions and non-synonymous mutations were overrepresented; (iii) two non-synonymous mutations affected the genes CTL0084 and CTL0610, encoding a putative transferase and a protein likely implicated in transcription regulation respectively, which are families known to be highly prone to undergone laboratory-derived advantageous mutations in other bacteria; and (iv) the mutation for E/CS88 is located likely in the regulatory region of a virulence gene (CT115/incD) believed to play a role in subverting the host cell machinery. Nevertheless, we found no significant differences in the growth rate, plasmid load, and attachment/entry rate, between strains before and after their long-term laboratory propagation. Of note, from the mixture of clones in E/CS88 initial population, an inactivating mutation in the virulence gene CT135 evolved to 100% prevalence, unequivocally indicating that this gene is superfluous for C. trachomatis survival in vitro. Globally, C. trachomatis revealed a slow in vitro adaptation that only modestly modifies the in vivo-derived genomic evolutionary landscape.

Hospital nurses tasks and work-related musculoskeletal disorders symptoms: A detailed analysis

BACKGROUND Hospital work-related musculoskeletal disorders (WRMSDs) symptoms are highly prevalent and nurses are considered the health care professional group more often affected by WRMSDs. OBJECTIVES Understanding the effects of nursing tasks on WRMSDs symptoms. METHODS Portuguese nurses answered to a modified Nordic Musculoskeletal symptoms Questionnaire. The increased likelihood of having WRMSDs symptoms was estimated from a daily working task schedule and the probability of suffering from lumbar WRMSDs symptoms intensity was also estimated. RESULTS Hospital nurses studied (n= 1.396) were mainly females (75.8%), and most of them reported more than 1 symptom (88%). Low-back pain was the most prevalent complaint (60.9%). Tasks performed more than 10 times a day, such as invasive procedures (OR = 2.142); care of hygiene and patient comfort in bed (OR = 2.484); patient mobilization in bed (OR = 2.022); and patient feeding (OR = 2.186) had an effect on dorsal and lumbar symptoms (p< 0.05).Those tasks involving invasive procedures were just the only ones producing symptoms simultaneously on every studied body part, such as lumbar, dorsal, wrist/hand and ankles/feet areas. CONCLUSIONS Tasks with a greater effect on low-back pain intensity were patient bed feeding and patient hygiene and care. We found, when analysing simultaneously the effects of every task on the likelihood of having low-back symptoms, that involving invasive procedures were that only ones affecting simultaneously the presence of almost all WRMSDs symptoms studied.

Risk factors for health care–associated infections: From better knowledge to better prevention

HighlightsTransfer from another hospital, skin problems, having a urinary catheter, and having a central line were the most significant risk factors for health care–associated infections present at admission.Having a central line was the main risk factor for health care–associated infections acquired during hospitalization.This study represents one of the first in Portugal to estimate the association between factors present at admission and during hospital stay in the development of health care–associated infections.This study may contribute to the design of an infection risk assessment tool to be applied in the future. Background: Health care–associated infections (HCAIs) are preventable with adoption of recognized preventive measures. The first step is to identify patients at higher risk of HCAI. This study aimed to identify patient risk factors (RFs) present on admission and acquired during inpatient stay which could be associated with higher risk of acquiring HCAI. Methods: A case‐control study was conducted in adult patients admitted during 2011 who were hospitalized for >48 hours. Cases were patients with HCAIs. Controls were selected in a ratio of 3:1, case matched by the admission date. The likelihood of increased HCAI was determined through binary logistic regression. Results: RFs identified as being the more relevant for HCAI were being a man (odds ratio [OR], 2.4; 95% confidence interval [CI], 1.2‐4.7), being aged >50 years (OR, 2.9; 95% CI, 1.3‐6.9), and having an insertion of a central venous line during hospital stay (OR, 12.4; 95% CI, 5.0‐30.5). Conclusions: RFs that showed statistical significance on admission were the patients intrinsic factors, and RFs acquired during hospitalization were extrinsic RFs. When a set of RFs were present, the presence of a central venous line proved to be the more relevant one.