Antimicrobial susceptibility and frequency of occurrence of clinical blood isolates in Sfax-Tunisia (1993-1998)

Antimicrobial susceptibility and frequency of occurrence of clinical blood isolates in Sfax-Tunisia (1993-1998). The choice of antimicrobial therapy for the treatment of bacteremia is often empirical and based on the knowledge of susceptibility profiles of the most common bacteria causing such infections. This study determines the bacterial etiology of bacteremic episodes and antimicrobial susceptibility patterns recorded at a teaching hospital, from January 1993 to December 1998. We collected 2979 strains responsible for bacteremia. Gram negative bacteria were predominant (60%). The organisms recovered most frequently were Staphylococcus aureus (18.9%), Escherichia coli (14.7%), Klebsiella pneumoniae (14%) and Pseudomonas aeruginosa (7.6%). The incidence of resistance to methicillin were 17.4% for Staphylococcus aureus and 26.8% for coagulase negative Staphylococcus. No resistance to glycopeptides was observed among the enterococci and staphylococci studied. 27.7% of enterobacteriaceae were resistant to third generation cephalosporins. Imipenem was the most active agent against gram negative bacteria. To carry out a surveillance of bacteremic episodes occurring at every hospital, it is necessary to provide valuable information which should be the basis for effective empiric therapy.     

Nosocomial outbreak of acute gastroenteritis in a neonatal intensive care unit in tunisia caused by multiply drug resistantSalmonella wien producing SHV-2 beta-lactamase

In a Tunisian hospital 27 babies, including 12 who were premature, in a single intensive care unit suffered acute gastroenteritis in the period from January to May 1988. The mean age at the onset of gastroenteritis was 8.4 days; nine babies died.Salmonella wien was isolated from stools (all babies) and blood (4 babies). It was also isolated from the stools of one nurse and from a mattress. Twelve of the babies had received cefotaxime, which was successfully replaced by oral colimycin. The outbreak was stopped by the implementation of infection control measures. All isolates ofSalmonella wien were of the same biotype, and had the same antibiotic resistance pattern (third generation cephalosporins, monobactams, aminoglycosides, chloramphenicol, trimethoprim and sulphonamides) and plasmid DNA restriction pattern. The isolates were all susceptible to a combination of cefotaxime and clavulanic acid (a -lactamase inhibitor), which displayed synergy, suggesting the presence of a -lactamase (geometric mean MICs 11.24 µg/ml for cefotaxime alone and 0.24 µg/ml in combination with 0.1 µg/ml potassium clavulanate). All isolates produced TEM-1 and SHV-2 -lactamase which was not transferable toEscherichia coli by conjugation. The presence of the SHV-2 enzyme inSalmonella wien may allow it to adapt to newer -lactams which is a cause for concern in this hospital.     

Red blood cell distribution width in Obstructive Sleep Apnea Syndromeand its association with cardiovascular disease

Background : Obstructive sleep apnea syndrome (OSAS) is associated with cardiovascular disease (CVD). Red blood cell distribution width (RDW) is reported as a novel marker of cardiovascular disease (CVD) risk. We aimed to investigate the correlation of RDW level with the severity of Obstructive Sleep Apnea Syndrome (OSAS) defined with the apnea–hypopnea index (AHI) and to study the relationship between RDW and CVD in OSAS. Methods: From retrospective analyses of patients admitted to our department for polygraphy between January 2018 and January 2020, OSAS patients with complete medical records and hemogram analyses were evaluated. Results: The study population consisted of 160 patients (101 females/59 males). The mean age was 52.32 ± 10.83 years. RDW correlated positively with the apnea hypopnea index (AHI) (r=0.392; p <0.0001) and C-reactive protein (CRP) (r = 0.3, p < 0.001). RDW and CRP were significantly higher in patients with CVD than whom without CVD (p <0.0001). In multivariate analysis, the independent predictors of CVD in OSAS were RDW (p<0.0001; OR=3.095; CI: 1.69-5.66), CRP (p=0.046; OR=1.136; CI: 1.002-1.287) and age (p=0.013; OR=1.085; CI: 1.017-1.157). The cut-off level for RDW with optimal sensitivity and specificity was calculated as 14.45 with sensitivity of 81% and specificity of 75%. Conclusions : The findings of this study suggest that RDW, a simple, relatively inexpensive and universally available marker could have the ability to predict CVD in OSAS.     

A tool for the management of personal protective equipment during COVID-19 pandemic: Abderrahmen Mami Hospital case study

Introduction: The COVID-19 pandemic is causing management difficulties in the Tunisian healthcare system inventory management and the supply of Personal Protective Equipment (PPE). Aim : Calculate the number of PPE needed for MAMI Hospital Ariana (dedicated hospital to COVID patients) to avoid stock-outs. Methods: This study proposed a calculation method of the PPE needs for the intensive care and pneumology departments. We developed a mathematical formulation of the number of PPE needed according to the number of visits per medical and other teams, their types, the number of patients, and the validity of each type of PPE. Results: Considering as input data: the number of visits for the different intervening teams (medical, paramedical, worker or other), the capacity of the different services (number of beds), the average length of stay of patients, the validity duration of an equipment and urgent visits, the developed model generates the required number of PPE (especially surgical masks, FFP2 masks, disposables gowns and coveralls). This allows to calculate the number of personal protective equipment (PPE) needed by the Mami hospital’s pharmacy in this period of COVID-19 crisis. Conclusion: Our configurable application allowed us to calculate PPE requirements for the intensive care and pneumology departments and estimate their use duration.     

Engineering of a recombinant trivalent single-chain variable fragment antibody directed against rabies virus glycoprotein G with improved neutralizing potency

Human and equine rabies immunoglobulins are currently available for passive immunization against rabies. However, these are hampered by the limited supply and some drawbacks. Advances in antibody engineering have led to overcome issues of clinical applications and to improve the protective efficacy. In the present study, we report the generation of a trivalent single-chain Fv (scFv50AD1-Fd), that recognizes the rabies virus glycoprotein, genetically fused to the trimerization domain of the bacteriophage T4 fibritin, termed ‘foldon’ (Fd). scFv50AD1-Fd was expressed as soluble recombinant protein in bacterial periplasmic space and purified through affinity chromatography. The molecular integrity and stability were analyzed by polyacrylamide gradient-gel electrophoresis, size-exclusion chromatography and incubation in human sera. The antigen-binding properties of the trimeric scFv were analyzed by direct and competitive-ELISA. Its apparent affinity constant was estimated at 1.4 ± 0.25 × 10⁹ M⁻¹ and was 75-fold higher than its monovalent scFv (1.9 ± 0.68 × 10⁷ M⁻¹). The scFv50AD1-Fd neutralized rabies virus in a standard in vitro and in vivo neutralization assay. We showed a high neutralization activity up to 75-fold compared with monovalent format and the WHO standard serum. The gain in avidity resulting from multivalency along with an improved biological activity makes the trivalent scFv50AD1-Fd construct an important reagent for rabies protection. The antibody engineering approach presented here may serve as a strategy for designing a new generation of anti-rabies for passive immunotherapy.