Guergana Petrova

Incidence of virulence determinants in clinical Enterococcus faecalis and Enterococcus faecium isolates collected in Bulgaria

OBJECTIVES To evaluate the prevalence of some virulence genes among 510 clinical Enterococcus spp. isolates and to assess the association of those genes with the species, infection site, and patient group (inpatients/outpatients). METHODS Adhesins genes (aggregation substances agg and asa1 of Enterococcus faecalis and Enterococcus faecium, respectively), enterococcal surface protein (esp), endocarditis-specific antigen A (efaA), collagen-binding proteins (ace/acm)); invasins (hyaluronidase (hyl) and gelatinase (gelE)); cytotoxines (activation of cytolysin (cylA) in E. faecalis); and modulators of the host immunity and inflammation (enhanced expression pheromone (eep) in E. faecalis) were detected by polymerase chain reaction. RESULTS The overall prevalence was: esp - 44.3%, agg/asa1 - 38.4%, ace/acm - 64.3%, efaA - 85.9%, eep - 69.4%, gelE - 64.3%, hyl - 25.1%, and cylA - 47.1%. E. faecalis isolates had significantly higher frequency of adhesin genes (esp and agg/asa1) and gelatinase in comparison to E. faecium. Multiple virulence genes in E. faecalis were significantly more prevalent than in E. faecium isolates. Domination of E. faecium with or without only one gene compared to the isolates of E. faecalis were found. Enterococcus spp. isolates obtained from outpatients compared to inpatients isolates had significantly higher frequency of agg/asa1, eep, gelE and cylA. Some adhesins genes (esp, agg/asa1 and efaA) had higher prevalence among the non-invasive Enterococcus spp. isolates compared to those causing invasive bacteremia, while ace/acm revealed higher dissemination in isolates causing invasive infections compared to non-invasive isolates. CONCLUSION Most E. faecalis attaches to abiotic surfaces in hospital environment, which correlates with higher prevalence of gene encoding for virulence factors involved in biofilm formation, such as enterococcal surface protein, aggregation substance, and gelatinase. The intestinal tract is an important reservoir for opportunistic enterococcal pathogens and allows them to access infectious sites through different virulence factors, demonstrated in outpatient isolates in this study.

Bulgarian cystic fibrosis Pseudomonas aeruginosa isolates: antimicrobial susceptibility and neuraminidase-encoding gene distribution.

Cystic fibrosis (CF) is an autosomal recessive disorder affecting multiple organ systems. The leading cause of morbidity and mortality is a progressive decline in pulmonary function resulting from airway damage caused by thickened secretions, complicated by chronic microbial infection. Pseudomonas aeruginosa is the most prevalent organism colonizing the lungs of CF patients (up to 80 % of the colonizations of lungs of patients aged .18 years) (Ramsey, 1996; CFF, 2002). It is rarely eradicated after colonization, regardless of the antimicrobial chemotherapy employed (Govan & Deretic, 1996). An extracellular neuraminidase is thought to play an important role in P. aeruginosa implantation of CF respiratory epithelium (Davies et al., 1999). Nevertheless, the bulk of clinical opinion supports the view that antibiotic therapy leads to improvement in lung function and improves survival of patients, particularly if aggressive treatment is begun on the first isolation of the organism.

Antimicrobial Activity of Tobramycin Against Respiratory Cystic Fibrosis Pseudomonas aeruginosa Isolates from Bulgaria

Abstract Tobramycin solution for inhalation (TSI) (Novartis pharmaceuticals) is indicated as chronic suppressive treatment for cystic fibrosis (CF) patients aged 6 years and older who are chronically infected by Pseudomonas aeruginosa. Inhaled administration of tobramycin assures high concentrations in the lungs of CF patients, improving the therapeutic ratio over that of parenteral tobramycin levels. Clinical and laboratory Standards institute (CLSI) breakpoints only consider parenteral levels and do not take into account these high antimicrobial concentrations. Therefore, the Spanish MENSURA Group has defined specific values for inhaled tobramycin when testing CF P. aeruginosa isolates (susceptible: minimal inhibitory concentration (MIC) ≤64 μg/ml; resistant: ≥128 mg/ml). In this study the antimicrobial activity of tobramycin against 120 respiratory CF P. aeruginosa isolates was determined by high-range Etest strips (LIOFILCHEM). Applying MENSURA breakpoints, 95% of the strains were categorized as susceptible. With ClSi breakpoints, the susceptibility rate decreased to 92.5%. The activity against non-mucoid P. aeruginosa was higher than that against mucoid isolates (MIC50=0.75 and MIC90=2 μg/ml vs. MIC50=1 and MIC90=4 μg/ml). The isolates obtained from patients untreated with TSI were more susceptible to the drug than those from patients receiving maintenance therapy with TSI (MIC50=0.75 and MIC90=1.5 μg/ml vs. MIC50=1.5 and MIC90=6 μg/ml). The isolates from patients with long-term P. aeruginosa colonization (over 5 years) revealed the highest tobramycin MICs (MIC50=1.00 and MIC90>1024 μg/ml). In conclusion, tobramycin has excellent in vitro activity against the studied CF isolates. Some factors such as isolate morphotype, pre-administration of TSI and duration of colonization influence its activity. Whenever TSI is considered for therapy, the CF P. aeruginosa strains categorized as intermediate or resistant to tobramycin according to the CLSI criteria should be recategorized by using the MENSURA interpretive criteria.

Measuring the bronchial reversibility in asthmatic children - clinical value of different indices

Background: Despite the long history of the BDR as a diagnostic tool there are still no commonly accepted rules for its performance and interpretation. There is no clear consensus about what affects the reversibility in children with bronchial obstruction. Aim: To define the clinical value of the BDR in asthmatic children and to validate different cut-offs and indices. Material and Methods: For a period of 2 years we evaluated medical history data of 211 children with asthma and 46 healthy children aged 5 to 17. For all children, we performed pre- and post-bronchodilator spirometry, specific IgE against aero- and food allergens and ACQ. Results: AUC for ΔFEV1% init. is 0.924 (95% CI 0,887-0,961) and the 6.15% threshold showed best sensitivity (82.8%) and specificity (100%). We analyzed alternative criteria for BDR compared to the classic one (∆FEV1%init.≥12%)- ∆MMEF25/75%init, ∆FVC%init. and ∆PEF%init. Best threshold for a positive BDR (ΔMMEF75/25% init.) is 29.9% with 84.1% sensitivity and 73.8% specificity. In children with asthma, independently from the initial FEV1 and the controller therapy, ∆FEV1%init.≥8% is associated with 2.369-fold (95% CI 1.077-5.213) higher risk for at least one hospitalization from the previous year and 2.871-fold (95% CI 1,239-6, 653) higher risk for school absence because of the asthma. Conclusion: BDR is widely used in confirming the diagnosis of asthma, but it can be a reliable method for monitoring the asthma control in children. Establishing a spirometry criteria adapted for children would improve substantially asthma control, therapeutic decisions making and identifying the risk of progressive loss of lung function.

Langerhans-Cell Histiocytoses - Epidemiology, Classification, Clinical Features, Diagnosis, Complications, Treatment and Prognosis

Summary Histiocytoses comprise a group of diverse diseases of unknown etiology with various clinical presentation and evolution. The underlying pathology is characterised by accumulation and infiltration of variable numbers of cells of the monocyte-macrophage line in the affected tissues and organs. Histiocytoses are divided into three major classes: Langerhans cell histiocytosis (LCH), non- Langerhans cell histiocytosis, and malignant histiocytic disorders. The term LCH (also known in the past as histiocytosis X) encompasses the following rare diseases: Eosinophilic Granuloma, Hand-Schuller-Christian disease, Letterer-Siwe disease, Hashimoto-Pritzker disease, in which accumulation of pathologic Langerhans cells (LCs) leads to tissue damage. LCs usually reside in the skin and ensure protection against infections by destroying foreign substances. LC accumulation is caused by antigen stimulation and inadequate immune response. Thus, clinical LCH manifestations range from isolated disease with mono- or multifocal bone lesions to disseminated multisystem disease. LCH is a rare disease, affecting mainly children and young smokers, aged 20-50 years. Lung involvement in LCH usually presents as a mono-system disease and is characterized by Langerhans cell granulomas (LCG) infiltrating and impairing the distal bronchioles. The definite diagnosis is based on lung biopsy of CAT selected LCG areas. So far, there is no an effective treatment, but the better understanding of the mechanisms involved in the pathogenesis of the disease would help in the development of effective therapeutic strategies in the future.

Antimicrobial susceptibility of pseudomonasaeruginosa in CF patients before and after regular treatment with inhaled tobramycin

Aim: To evaluate antimicrobial susceptibility of Pseudomonas aeruginosa , isolated from CF patients before and after initiation of regular therapy with inhaled tobramycin. Methods: For the period of 2006–2013 we evaluated sputa from 118 CF patients (50 females and 68 males) aged 5 to 34 years of age. We evaluated the antimicrobial susceptibility towards 17 antimicrobials, according CLSI recommendations. Results: In the sputa of 70 patients(32 males and 38 females) a total of 102 isolates of P . aeruginosa were found. Age distribution was as follows: 42,1% of all children under 9 years of age, 57,9% for children aged 10 to 16 years and 86,9% for patients over 16 years of age. 68 out of 102 (66.7%) were susceptible to all 17 studied antimicrobials. Low resistance levels were found towards: imipenem (5.9%), meropenem (3.9%), amikacin (3.9%), gentamicin (7.8%), tobramycin (5.9%), netilmicin (13.7%) and ciprofloxacin (13.7%). In Bulgaria the first inhaled tobramycin regimens were introduced in 2007 and this treatment became regular in 2009. We divided the isolates before 2009 (64) and after 2009 (38). Significant reduction (p<0,001–0,02) in susceptibility for the strains after 2009 was noted towards piperacillin (100% vs 50%), ceftazidime (100% / 77,3%), cefepime (97,9% / 68,2%), amikacin (100% / 63,6%), gentamicin (95,7% / 40,9%), tobramycin (93,6% / 59,1%) and ciprofloxacin (93,6% / 45,5%). Conclusion: Introducing regular inhaled tobramycin therapy changed significantly antimicrobial resistance of P . aeruginosa . Nowadays the strategic for Bulgaria anti-pseudomonas antibiotic is colimycin with still 100% susceptibility of all isolates.

Severe asthma and allergy - should we look for the allergens

Material and method For a period of 6 months we evaluated medical history data of 29 children with asthma divided into two groups 14 (6 girls, 8 boys) with severe asthma (SA) on high dose combined inhaled corticosteroids (ICS) and 15 (6 girls, 9 boys) with moderate asthma, matched by age to serve as a control group. For all children we performed pulmonary function tests (PFT), nasal smears for eosinophil counts, drew blood for IgE against inhalation and food allergies antibodies detection and ACQ. IgE were detected with the predesigned kit EurolinePediatric.

Severe asthma in adolescence - or how the low self-esteem obstacles the therapy

Clinical case We present a case of 17-year old girl with bronchial asthma, hospitalized in the clinic multiple times, despite high dose of combined corticosteroids as a controller medication. The child starts to show protest behavior towards therapy, that’s modifying in the course of psychological maturation – denial of the medicines, unhealthy and hazardous life styles. At the age of 16-years depression was diagnosed, and was pharmacological and psychological therapy. This case is presented with aim to show specific for most of the asthmatic patients’ negative selfestimation for their quality of life and how it requires complex theurapetical approach.

Long-term inhaled corticosteroid treatment and severe asthma in children - the impact on body height and weight

Background Chronic conditions such as asthma are usually stigmatized as one of the reasons for short stature. A widespread belief also is that prolonged long-term treatment with corticosteroids will lead to elevated body weight and also could lead to short stature. Therefore we evaluated the height and weight status in the children admitted in the hospital for asthma attack regarding the asthma severity, the natural history of asthma and inhaled corticosteroid (ICS) treatment period.

Pulmonary Gangrene - Severe And Rare Complication Of Pneumonia

Summary Pneumonia is an inflammatory lung disorder characterized by consolidation due to presence of exudates in the alveolar spaces. Most pneumonias can be effectively treated with appropriate oral antibiotics, with intravenous antibiotics being reserved for those with severe infections. We present two cases of girls admitted in our clinic with pneumonia where our conventional therapy was not sufficient. Case 1: A 15-year-old girl with cystic fibrosis, with left lobular pneumonia, for which an aggressive conservative treatment was initiated. After significant improvement, sudden detorioration and pneumothorax of the left lung occurred. She was transferred to the surgical department for intervention. Due to failure to respond to initial drainage she underwent thoracotomy and resection of the left lower lobe of the lung. The histology result confirmed gangrene. Case 2: A four-year old girl was treated for pneumonia in the right lung with aggressive intravenous antibiotic. After temporary improvement sudden deterioration was observed. The patient was transferred to the surgery department, where pulmonary gangrene was confirmed. After the lower lobe of the right lung was resected, she was discharged in good health. The careful follow up, accurate diagnosis and correct medication choice are crucial for reducing the complications of “common” pneumonia.