TABLE OF CONTENT

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1. MULTIDRUG RESISTANT TUBERCULOSIS IN BULGARIA – MICROBIOLOGICAL ASPECTS

S. Yordanova, E. Bachiyska, Y. Atanasova, Y. Todorova, A. Baikova, T. Kantardjiev

ABSTRACT
The aim of the study was to examine the multidrug resistant tuberculosis (MDR-TB) in Bulgaria in 2012 using microbiological methods (phenotypic and genetic testing) and to describe its distribution in the country.

The clinical isolates of 67 patients were confirmed in NRL TB, NCIPD as MDR-TB in 2012. The conventional drug susceptibility testing (DST) was performed by BАСТЕС MGIT 960 System to first (FLDs) and second line drugs (SLDs) using the following critical concentrations: Streptomycin (STR) 1,0 μg/ml, Isoniazid (INH) 0,1 μg/ml, Rifampin (RMP) 1,0 μg/ml, Ethambutol (EMB) 5,0 μg/ml, Ofloxacin (OFL) 2,0 μg/ml, Amikacin (AMK) 1,0 μg/ml, Kanamycin (KAN) 5,0 μg/ml and Capreomycin (CAP) 2,5 μg/ml. The mutations in the relevant genes were detected by GenoType® MTBDRplus and GenoType®MTBDRsl.

Nearly half of the MDR-TB strains (47,76%) were resistant to all of the tested FLDs. The majority of the MDR-TB isolates were sensitive to SLDs – 83,58%, whereas 8,96% (n= 6) were defined as XDR-TB (Extensively drug resistant tuberculosis). The most common mutation in the rpoB gene was S531L (88, 06%). The C15T mutation in the regulatory region of the inhA gene was much more frequent (n=29) than the S315T1 one in katG (n=18).

The highest prevalence of MDR-TB in Bulgaria was in the districts of Plovdiv, Montana and Vidin. There were five cases of MDR-TB in the penitential system found in prisoners. One of these patients was a woman.


2. ANTIMICROBIALS’ RESISTANT SALMONELLA STRAINS TESTED FOR SUSCEPTIBILITY TO HYBRID MATERIAL WITH INCLUDED SILVER NANOPARTICLES

M. Iliev

ABSTRACT
Salmonella infections are of great public importance because of the wide geographical distribution, high infectiveness regardless of age and the fact that they are antropozoonoses. The most common causes of salmonellosis have been isolated from human serovars Salmonella Enteritidis and Salmonella Typhimurium. Salmonella enterica serovar Infantis is isolated with high frequency in poultry farms. Because of reported increase in antibiotic resistance of isolated Salmonellas, monitoring of silver resistance in clinical Salmonella isolates was undertaken. The purpose is to establish the possibility of a therapeutic choice of hybrid materials comprising silver nanoparticles /AgNps/ in isolates that are resistant to more than two antibiotics. The test was conducted by the method of two-fold serial macro-dilutions according CLSI M26-A and certain MBС /Minimal Bactericidal Concentrations/ of the hybrid material PVA /polyvinyl alcohol/ /AgNps against the tested strains. Tests performed found synergistic effects in the combination of ceftazidime and PVA / AgNps. The strains with the highest levels of MBС (1.1 mg / L) would be subject of testing for a carriage of genes for silver resistance.


3. ESBL PRODUCING STRAINS KLEBSIELLA AND THEIR SUSCEPTIBILITY TO HYBRID PVA/AGNPS MATERIAL

M. Iliev

ABSTRACT
Klebsiella infections are of great public importance because of the wide geographical distribution. Klebsiella species are ubiquitous in nature. Drug resistant isolates remain an important hospital-acquired bacterial pathogen, add significantly to hospital stays, and are especially problematic in high impact medical areas such as intensive care units. The purpose of this paper is to establish the possibility of a therapeutic choice of hybrid materials comprising silver nanoparticles /AgNps/ in isolates that are resistant to more than two antibiotics. The test was conducted by the method of two-fold serial macro-dilutions according to CLSI M26A and certain MBС /Minimal Bactericidal Concentrations/ of the hybrid material PVA/polyvinyl alcohol//AgNps against the tested strains. Synergistic effect was observed on tested Klebsiella strain in combination with the hybrid material due to Ceftazidime strong bactericidal activity of the silver-containing liquid polymer. However, we can assume that there is a reason to test the strains with a MBC equal or more than 1.1 mg/L for the presence of a plasmid with silver resistance carrying genes.


4. MOLECULAR EPIDEMIOLOGY SURVEILLANCE OF PURE HIV-1 SUBTYPES IN BULGARIA

I. A. Ivanov, D. Beshkov, I. Elenkov, M. Stoicheva, D. Nikolova

ABSTRACT
A limited information is available to describe pure HIV-1 subtypes distributed in Bulgaria. Thus, the objective of the present study was to perform a comprehensive molecular epidemiological survey of HIV-1 in Bulgaria with a focus on pure HIV-1 subtypes to better characterize the HIV-1 epidemic. In this regard we analyzed 202 polymerase (pol) sequences from pure HIV-1 subtypes isolated from Bulgarians diagnosed until 2009. Epidemiologic and demographic information as well as phylogenetic analysis was used to infer HIV-1 evolutionary histories of studied populations. Our analysis classified 120 (59.4%) of the 202 Bulgarian HIV-1 samples to five different major pure subtypes. 104 (51.5%) were subtype B, 7 (3.5%) were subtype С, 5 (2.5%) were subtype А1, 2 (1.0%) were subtype F1, and two (1.0%) were subtype H. In addition, the phylogenetic analysis of subtype B sequences showed that this subtype has been introduced into Bulgaria on multiple occasions followed by local expansion. Our analysis revealed the presence of a substantial increase in the spread of HIV-1 subtype B among MSM which are among the most vulnerable groups of the population and highlights the importance of sustaining and expanding a surveillance to prevent and control HIV-1 infection in Bulgaria.


5. MOLECULAR EPIDEMIOLOGY SURVEILLANCE OF HIV-1 CRFS AND URFS IN BULGARIA

I. A. Ivanov, D. Beshkov, I. Elenkov, M. Stoicheva, D. Nikolova

ABSTRACT
Little is known about the introduction and dissemination of circulating recombinant forms of HIV-1 in Bulgaria. To fill the gap, we analyzed 202 polymerase (pol) sequences from Bulgarians diagnosed through 2009. The phylogenetic analysis showed that 120 persons (59.5%) were infected with one of five different HIV-1 subtypes (A1, B, C, F1 and H) and 82 individuals (40.6%) were infected with circulating recombinant forms (CRFs) or unique recombinant forms (URFs): 63 persons (31.2%) had one of six different CRFs: 01_AE, 02_AG, 04_cpx, 05_DF, 14_BG, and 36_cpx. We also identified for the first time an infection with two different clusters of unique A-like and F-like genetic forms in 12 persons (5.9%) and seven additional unique recombinant forms (3.5%), including a novel J/C recombinant. CRF01_AE was the most common recombinant form and was higher in women and IDUs (intravenous drug users) relative to other risk groups combined. Our results show that the HIV-1 infection in Bulgaria reflects the shifting distribution of genotypes coincident with the changing epidemiology of the HIV-1 epidemic among different risk groups. The data of our study support increased public health interventions targeting IDUs and highlight the importance of sustained and expanded surveillance to prevent and control the HIV-1 infection in Bulgaria.


6. ASPERGILLUS SPECIES AS A SYSTEMIC PATHOGEN ISOLATION AND IDENTIFICATION OVERVIEW

K. Dimitrov

ABSTRACT
Systemic Aspergillosis is the most common pathogenic disease in immunosuppressed hosts. Among the patients of highest risk are the ones undergone surgery, bone-marrow transplantation or solid organ transplantation, cytotoxic or corticosteroid chemotherapy, HIV-infection. Aspergillus fumigatus, A. flavus, A. niger, and A. terreus are the most common Aspergillus species that cause systemic infection. Infection caused by this species invades generally internal organs and most of the cases have a lethal outcome. This overview is focused on the diagnostic methods and rapid identification of invasive and non-invasive mycosis caused by species of Aspergillus. The rapid detection and identification of Aspergillus in clinical laboratories are extremely important for the management of patients with systemic aspergillosis.


7. CANDIDA SPECIES AS A SYSTEMIC PATHOGEN. ISOLATION AND IDENTIFICATION OVERVIEW

D. Dimitrov

ABSTRACT
Fungi can be the cause of many nosocomial infections. Systemic fungal infections in many cases are targeted at patients or individuals with weak immune system suffering from neutropenia, human Immunodeficiency virus (HIV) or undergoing chemotherapy and etc. One of the most common systemic fungal infection is caused by the genus Candida from which Candida albicans takes the most significant part. Systemic fungal infections are very dangerous because they cannot be diagnosed by a common trait that characterizes the current pathogen.This is because the fungi can travel through blood and disseminate in any organ and therefore cause a variety of symptoms linked to the affected organ. The early identification of the fungus is critical for an appropriate treatment. In that regard we need to know how to isolate properly the pathogen avoiding false positive results, so that we can identify it. In this overview we will discuss these steps focusing on systemic infections caused by Candida albicans. The genus and is widely spread in all our surroundings, including places that are supposed to be free of contamination as hospitals and others.


 

 Editor-in-Chief
Prof. T. Kantardjiev, MD, DSc

Editorial Board
Acad. B. Petrunov, MD, DSc
Prof. I. Christova, MD, DSc
Prof. M. Kojuharova, MD, PhD
Assoc. Prof. I. Rainova, MD, PhD
Assoc. Prof. P. Teoharov, MD, PhD

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