Comparative evaluation of aggressiveness traits in staphylococcal strains from severe infections versus nasopharyngeal carriage.

Despite their commensal status, staphylococci can become problematic pathogens expressing multiple and redundant virulence factors. This study aimed to evaluate aggressiveness markers comparatively in staphylococcal strains isolated from severe infections versus asymptomatic carriage in order to identify clinically relevant bacterial traits that could easily be detected in clinical practice and could be suggestive for particular host-pathogen interactions such as cyto-adhesion or biofilm formation, ultimately orienting the clinical decision-making process. We have used in vitro phenotypic methods to assess adhesion to and invasion of eukaryotic cells, biofilm development, and expression of soluble virulence factors in 92 Staphylococcus spp. strains. The adhesion index, invasion capacity, biofilm formation and expression of soluble factors did not differ significantly between clinical and commensal strains. The major bacterial traits we found to be significantly more prevalent in clinical staphylococci were the aggregative adhesion pattern (P = 0.012), cluster adhesion (P = 0.001) and tetrad morphology (P = 0.018). The aggregative adhesion pattern was correlated with higher cyto-adhesion (P < 0.001), higher invasion capacity (P = 0.003) and lower Carmeli scores (P = 0.002). Three major bacterial traits, namely tetrad morphology, aggregative adhesion pattern, and resistance to methicillin (acronym: TAM), can be used to compute an aggressiveness score (SAS) predictive of the staphylococcal strain's virulence and capacity to initiate and develop a biofilm-driven chronic infectious process versus a fulminant acute infection, in a susceptible host.

Clostridium Difficile Associated Disease: Burden of and Predictors for in Hospital Fatal Outcome. Results of a Hospital-Based Study, Bucharest, Romania.

INTRODUCTION: In the last 15 years Clostridium difficile infection became a typical new emergent threat worldwide. Our aim was to describe the risk factors associated with fatal outcome of Clostridium difficile associated disease (CDAD) cases treated in 2012 in "Dr Victor Babes" Infectious and Tropical Diseases Hospital, a 450 beds teaching clinic from Bucharest, Romania. MATERIAL AND METHODS: Retrospective cohort study - the case records of hospitalized patients in the year 2012, presenting with diarrhea and that tested positive for C difficile through toxin A and B assays were reviewed. Data collected through chart review of CDAD were demographic and clinical. A Charlson comorbidities index score was allocated to each case. An EpiInfo data base was fed with demo and clinical data - software's facilities were used for univariate analysis (Chi square) and also for logistic regression. RESULTS: In study were included all 326 hospitalization episodes with a discharge diagnosis of CDAD in 2012. Overall, 30 of the 326 CDAD patients (9.2%) versus 289 of the 18636 non-CDAD patients (1.55%) died during their hospital stay, resulting in a relative risk of pre-discharge death of 5.93 (4.14- 8.50) for CDAD patients, a CDAD attributable risk of death of 7.65 per 100 patients and a CDAD attributable fraction of 83.15 % (70.1-86%). Unconditional logistic regression retained as fatal outcome predictors the following: (a) a Charlson comorbidity index score >3: (OR: 3.03; CI 95%: 1.21-7.54), (b) ICU stay: (OR: 15.81; CI 95%: 4.47- 55.89) and (c) age >64 years: (OR: 2.95; CI 95%: 1.15-7.69). CONCLUSION: Our findings add to the understanding of Clostridium difficile fatal outcome and they have implications for prevention and therapy - the case fatality of 9.2% underlines the importance of the increased efforts in CDAD prevention.

SCREENING OF PROTEASE INHIBITORS RESISTANCE MUTATIONS IN HEPATITIS C VIRUS ISOLATES INFECTING ROMANIAN PATIENTS UNEXPOSED TO TRIPLE THERAPY.

Although the European recommendations include the use of new antiviral drugs for the treatment of hepatitis C, in Romania the current treatment remains interferon plus ribavirin. First generation viral protease inhibitors (i.e. boceprevir, telaprevir), which have raised the chances of obtaining viral clearance in up to 70% of infection cases produced by genotype 1 isolates, have not been introduced yet as standard treatment in our country. The success of these new antivirals is limited by the occurrence and selection of resistance mutations during therapy. We set-up a molecular study aiming to detect any resistance mutations to boceprevir and telaprevir harbored by hepatitis C isolates infecting Romanian patients naïve to viral protease inhibitors. Since these new antivirals are efficient and approved for genotype 1 infection, viral samples were genotyped following a protocol previously developed by our research group. We analyzed by both population sequencing and molecular cloning and sequencing the NS3 protease region of hepatitis C virus isolates infecting patients which were not previously exposed to boceprevir and telaprevir. All the analyzed samples were subtype 1b and resembled the samples collected in recent years from Romanian patients. Molecular cloning followed by sequencing showed great intra-host diversity, which is known to represent the source of isolates with different resistance phenotypes. Both population sequencing and molecular cloning followed by clone sequencing revealed two boceprevir resistance mutations (T54S and V55A), respectively, a telaprevir resistance mutation (T54S) in the sequences obtained from a patient with chronic hepatitis C. To our knowledge, this is the first study indicating the existence of pre-treatment resistance mutations to boceprevir and telaprevir in hepatitis C virus isolates infecting Romanian patients.