Department of Pathogenic Bacteria
Hristo Najdenski, PhD, Associate Professor
Head of Department
E-mail: usema@bas.bg
Tel: (+359 2) 979-31-61
Tatyana Radoucheva, PhD, Assoc. Professor
E-mail: tradoucheva@abv.bg
Tel: (+359 2) 979-31-68
Nadya Markova, PhD, Assoc. Professor
E-mail: nadya.markova@gmail.com
Tel: (+359 2) 979-31-68
Vesselin Kussovski, PhD, Assoc. Professor
E-mail: vkussovski@yahoo.com
Tel: (+359 2) 979-31-68
Anna Vesselinova, Dr. Sc., Professor
E-mail: MStoy@abv.bg
Tel: (+359 2) 979-31-70
Neli Slavova-Azmanova, PhD, MD
E-mail: nellystz@yahoo.com
Tel: (+359 2) 979-31-72
Elica Golkocheva-Markova, PhD
E-mail: golkocheva@microbio.bas.bg
Tel: (+359 2) 979-31-61
Mariana Ninova, MSc
Tel: (+359 2) 979-31-48
Neli Georgieva, DVM
Tel: (+359 2) 979-31-68
Iva Tzvetkova, MSc
E-mail: likovska@abv.bg
Tel: (+359 2) 979-31-48
Miroluba Ilieva
E-mail:
Tel: (+359 2) 979-31-61
Anton Caro, DVM
E-mail: anton_caro@abv.bg
Tel: (+359 2) 979-31-70
Mihail Iliev, PhD-student
E-mail: Iliev@microbio.bas.bg
Tel: (+359 2) 979-31-61
Violeta Valcheva, PhD-student
E-mail: vivi088@abv.bg
Tel: (+359 2) 979-31-68
Albena Cherneva
Tel: (+359 2) 979-31-68
Radka Georgieva
Tel: (+359 2) 979-31-61
Main Research Topics:
 Factors and mechanisms of bacterial virulence
 Bacterial-host interactions in zoonoses and particularly dangerous infections
 Surface bacterial structures and bioenergetic mechanisms
 Sunlight and the survival of Enterobacteriaceae bacteria in water ecosystems
 Influence of environmental factors on the survivability of pathogenic yersiniae epidemiology and prevention.
 Detection and enumeration of pathogens in products of animal origin by using the
polymerase chain reaction.
 In vitro determination of antibacterial and antifungal activity of substances with
organic and non-organic origin.
 Photophysical and photosensitizing properties of phthalocyanine complexes as
antibacterial and antiviral agents
 Molecular characterisation of Mycobacterium tuberculosis strains and Monitoring the
burden and transmission of tuberculosis in Bulgaria; Incidence of multidrug-resistant
TB (MDR-TB); Genotypic detection of drug resistant mutations
Projects
National
Virulence factors of Yersinia and their application
Project leader: H. Najdenski, PhD
Grant К-1406/2004 from the National Scientific Research Council, Republic of Bulgaria
Characterization of physicochemical and catalitical properties of bacterial uridine
monophosphate kinases
Project leader: N. Slavova-Azmanova, MD,
Grant MU-К-1406/2004 from the National Scientific Research Council, Republic of Bulgaria
Incidence and nature of the phenomenon “heteroresistance” in methicilin resistant staphyloc
occi
Project leader: N. Markova, PhD
Grant 19/2004. Contract research agreement between Medical University of Plovdiv and
Institute of Microbiology, BAS, Republic of Bulgaria
Photodynamic inactivation of pathogenic bacteria and viruses by phthalocyanines: ecological
and medical aspects
Project leader: V.Kussovski, PhD
Grant B-1534/05 from the National Scientific Research Council, Republic of Bulgaria
International
Optimization of molecular typing methods for Campylobacter
Project leader: H. Najdenski Advisors: L. Herman, PhD, V. De Jonghe, PhD
Grant of the Belgium Ministry of Science and Education
Physicochemical and biochemical studies of recombinant bacterial enzymes involved in
nucleoside metabolism
Project leader: N. S. Slavova-Azmanova, MD,
Grant RIG.981473 from NATO Security through Science Program
Intervention strategy against the development of multidrug-resistant tuberculosis during
therapy
Project leader: N. Markova, PhD
Grant NATO EAP.CLG.980734 TBC/2004-2006
Molecular epidemiology of tuberculosis in Bulgaria
Project leader: N. Markova, PhD
Contract research agreement between St. Petersburg Pasteur Institute, Russia and Institute of
Microbiology, BAS, Bulgaria
Application in clinical proteomics in Yersinia diagnosis
Project leader: E. Golkocheva, PhD
Advisors: H. Najdenski, PhD, R. Stoilov, PhD
Grant RIG.981256 from NATO Security through Science Program
Selected Publications (2000-2006) :
Markova N., Kussovski V., Radoucheva T., Dilova k., Georgieva N. Effects of
intraperitoneal and intranasal application of Lentinan on cellular response in rats. Intern.
Immunopharmacol., 2002, 2, 1641-1645.
Najdenski H., Michailov Y., Nikolova S., Vesselinova A. Protective effect of Oxadin on
experimental Yersinia enterocolitica infection in rats. Pharmazie, 2002, 57, 337-339.
Najdenski H., Vesselinova A. Experimental mixed infection of rabbits with Yersinia
enterocolitica and Listeria monocytogenes. J. Vet. Med. B, 2002, 49, 97-104.
Taskova R., Mitova M., Najdenski H., Tzvetkova I., Duddeck H. Antimicrobial activity
and cytotoxicity of Carthamus lanatus. Fitoterapia, 2002, 73, 540-543.
Kamenarska Z., Gasic M.G., Zlatovic M., Rasovic A., Sladic D., Kljajic Z., Stefanov K.,
Seizova K., Najdenski H., Kujumgiev A., Tsvetkova I., Popov S. Chemical composition of
the brown alga Padina pavonia (L.) Gaill. from the Adriatic sea. Bot. Mar., 2002, 45, 339-345.
Kamenarska Z., Dimitrova-Konaklieva St., Stefanov K., Najdenski H., Tsvetkova I.,
Popov S. Comparative study on the volatile compounds from some Black sea brown algae.
2002, 45, 502-509.
Najdenski H., Vesselinova A., Golkocheva E., Garbom S., Wolf-Watz H.
Characterization of infections with wild and mutant Yersinia pseudotuberculosis strains in
rabbit oral model. In: The Genus Yersinia. (Edited by M. Skurnik et al.), Kluwer Plenum,
2003, 117-120.
Najdenski, H., Vesselinova, A., Golkocheva, E., Garbom, S., Wolf-Watz, H.
Experimental infections with wild and mutant Yersinia pseudotuberculosis strains in rabbits.
J. Vet. Med. B, 2003; 50, 280-288.
Najdenski, H., Golokocheva, E., Vesselinova, A., Bengoechea, J-A., Skurnik, M. Proper
expression of the O-antigen of lipopolysaccharide is essential for the virulence of Yersinia
enterocolitica O:8 in experimental oral infection of rabbits. FEMS Immunol. Med. Microbiol.,
2003; 38, 97-106.
De Rosa, S., Kamenarska, Z., Stefanov, K., Dimitrova-Konaklieva, S., Najdenski, C.,
Tsvetkova, I., Ninova, V., Popov, S. Chemical composition of Corallina mediterranea
Areschoug and Corallina granifera Ell. et Soland. Z. Naturforsch., 2003; 58c, 325-332.
Bengoechea J.A., Najdenski H., Skurnik M., Essential role of the lipopolysaccharide Oantigen status of Yersinia enterocolitica O:8 in virulence and in the outer membrane
regulatory network. Mol. Microbiol., 2004, 52: 451-469.
Najdenski H., Golkocheva E., Vesselinova A., Russmann H., Comparison of the course
of infection of virulent Yersinia enterocolitica serotype O:8 with an isogenic soda mutant in
the peroral rabbit model. Int. J. Med. Microbiol., 2004; 294: 383-393.
Ivanova V., Graefe U., Schlegel B., Kolarova M., Aleksieva K., Najdenski H.,
Tzvetkova I., Chipeva V., Usnic acid, metabolite from neuropogon sp., an antarctic lichen
isolation, structure elucidation and biological activity. Biotechnol. & Biotechnol. Eq., 2004;
18: 66-71.
Kamenarska Z., Stefanov K., Dimitrova-Konaklieva S., Najdenski H., Tsvetkova I., and
Popov S., Chemical composition and biological activity of the brackishwater green alga
Cladophora rivularis (L) Hoek. Botanica Marina, 2004; 47: 215-221.
Najdenski, H., V.Kussovski, A.Vesselinova. Experimental Burkholderia pseudomallei
infection of pigs. J. Vet. Med. B 2004; 51: 225-230.
Ignatova M, Voccia S, Gilbert B, Markova N, Mercuri PS, Galleni M, Sciannamea V,
Lenoir S, Cossement D, Gouttebaron R, Jerome R, Jerome C. Synthesis of copolymer brushes
endowed with adhesion to stainless steel surfaces and antibacterial properties by controlled
nitroxide-mediated radical polymerization. Langmuir. 2004; 20 (24):10718-26.
Markova, N., L. Michailova, V. Kussovski, M. Jourdanova, T. Radoucheva. Intranasal
application of Lentinan enhances bactericidal activity of rat alveolar macrophages against
Mycobacterium tuberculosis. Pharmazie, 2005; 60 (1): 42-48.
Popova M., Bankova V., Naydensky Ch., Tsvetkova I., and Kujumgiev At. Comparative
study of the biological activity of propolis from different geographic origin: a statistical
approach. Macedonian pharmaceutical bulletin, 2004; 50: 9-14.
Trusheva B., Popova M., Naydensky H., Tsvetkova I., Gregorio Rodriguez J., and
Bankova V. New polyisoprenylated benzophenones from Venezuelan propolis. Fitoterapia,
2004; 75: 683-689.
Assairi, L., Bertrand, A., Ferdinand, J., Slavova-Azmanova, N., Christensen, M.,
Briozzo, P., Craescu, C., Schaeffer, F., Neuhard, J., Barzu, O., Gilles, A.-M. Deciphering the
function of an ORF: Salmonella enterica Deo M protein is a new mutarotase specific for
deoxyribose Protein Science 2004, 13, 1295-1303.
Najdenski H., Rijpens N., Tcherneva E., Herman L., Subtractive hybridization and PCR
amplification for detection of Brucella spp. In: Medical aspects of the fight against chemical
and biological terrorism and mass traumatism, (ed. Monov A., Dishovsky Ch.), v.1, 2004
Markova N, Michailova L., Kussovski V, Jourdanova M, Radoucheva T. Intranasal
application of lentinan enhances bactericidal activity of rat alveolar macrophages against
Mycobacterium tuberculosis. Pharmazie. 2005 Jan; 60(1):42-8.
Drandarska, I, Kussovski, V., Nikolaeva, S., Markova, N. Combined
immunomodulating effects of BCG and Lentinan after intranasal application in guinea pigs.
International Immunopharmacology. 2005 Apr;5 (4):795-803.
Michailova, L, Kussovski, V., Radoucheva, T., Jourdanova, M., Berger, W., Rinder, H.,
Markova, N. Morphological variability and cell wall deficiency of Mycobacterium
tuberculosis in “heteroresistant” strains isolated from newly diagnosed tuberculosis patients.
The International Journal of Tuberculosis and Lung Disease. 2005 Aug;9 (8):907-14.
Bonovska, M., Tzvetkov, Y., Najdenski, H., Bachvarova, Y. PCR for detection of
Mycobacterium tuberculosis in experimentally infected dogs. J. Vet. Med., 2005, 52(10), 5-8.
Ivanova, A., B. Mikhova, H. Najdenski, I. Tzvetkova, I.Kostova. Antimicrobial and
cytotoxic activity of Ruta graveolens. Fitoterapia, 76, 2005, 344-347.
Славова-Азманова, Н. Х. Найденски, Антибиотична резистентност – молекулярни
механизми и механизми за нейното преодоляване. – Инфекциозни заболявания, 36,
2005, 2, 3-22.
Najdenski, H., Golkocheva, E., Kussovski, V., Ivanova, E., Manov, V., Iliev M.,
Vesselinova, A., Bengoechea, J.A., Skurnik, M. Experimental pig yersiniosis to assess
attenuation of Yersinia enterocolitica O:8 mutant strains. FEMS Immunol. Med. Microbiol.,
47, 425-435, 2006.
Yordanov, M., Golkocheva, E., Najdenski, H. Modulation of complement activity in
vitro and in vivo by Yersinia wild and mutant strains. Folia Microbiol., 51, 27-32, 2006.
Mokrousov, I., Jiao,W.W., Valcheva, V., Vyazovaya, A., Otten, T., Ly, H. M., Lan, N.
N., Limeschenko, E., Markova, N., Vyshnevskiy, B., Shen, A.D., Narvskaya O. Rapid
Detection of the Mycobacterium tuberculosis Beijing genotype and its ancient and modern
sublineages by IS6110-based inverse PCR. J. Clin. Microbiol., 44: 2851–2856, 2006.
Mokrousov, I., Jiao, W.W., Sun, G.Z., Liu, J.W., Valcheva, V., Li, M., Narvskaya, O.,
Shen, A.D. Evolution of drug resistance in different sublineages of Mycobacterium
tuberculosis Beijing genotype. Antimicrob. Agents and Chemotherapy, 50, 2820-2823, 2006.
Ignatova, M., Voccia, S., Gilbert B., Markova, N., Cossement, D., Gouttebaron, R.,
Jérôme, R and Ch. Jérôme .Combination of electrografting and atom-transfer radical
polymerization for making the stainless steel surface antibacterial and protein antiadhesive.
Langmuir, 22, 255 –262, 2006.
Ignatova, M., Starbova, K., Markova, N., Manolova, N., Rashkov, I. Electrospun nanofibre mats with antibacterial properties from quaternised chitosan and poly (vinyl alcohol).
Carbohydrate Research, 341, 2098-2107, 2006.
Golkocheva, E., Stoilov, R., Najdenski, H. Serological findings in blood sera of patients
with Yersinia-triggered arthritis. Clin. Microbiol. Infect., 12 (s4), P1739, 2006.
Carballeira, N., Ivanova, A., Wagner, K., O’Neill, R., H. Najdenski, Tsvetkova, I.,
Stefanov, K. Fatty acid composition of Staphylococcus epidermis strain isolated from lake
Pomorie in Bulgaria. Compt. Rend. Acad. Bulg. Sci., 59, 8, 849-852, 2006.
Konakchiev, A., Todorova, M., Mikhova, B., Vitkova, A., Najdenski, H., Duddeck, H.
Chemical composition and antimicrobial activity of the essential oil from two Achillea collina
Becker. Compt. Rend. Acad. Bulg. Sci., 59, 5, 505-510, 2006.
Голкочева, Е., Стоилов, Р., Найденски, Х. Реактивен артрит асоцииран с Yersinia
enterocolitica – патогенеза и диагноза, Ревматология, 3, 2006.
Slavova-Azmanova, N. Purification and biochemical characterization of UMP kinaze
from Streptococcus pneumoniae. Compt. Rend. Acad. Bulg. Sci., 59, 859-864, 2006.
Хайдушка И , Мурджева, М., Вълчева, В., Маркова, Н. Адхезивни свойства,
вирулентност и физиологични характеристики на клинични метицилин- резистентни
изолати Staphylococcus aureus. Инфектология, 3, 2006.
Most Important Achievements:
 The increased growth ability and virulence of septicaemic pathogens in animal corps
was found, and the relationship of this phenomenon to the changes in energetic
metabolism of the bacteria was proved.
 Pathogenic strains of the species Yersinia enterocolitica have been isolated from
children with gastrointestinal disorders, from tonsils of pigs, as well as from the
viscera of wild animals (boars, wild cats, deers, birds, and fishes). Microorganisms of
the species Yersinia pseudotuberculosis (serotypes 0:1, 0:2, 0:3, and 0:5) have been
isolated from the viscera of boars, wild cats and birds.
 Yersinia outer membrane proteins have been isolated and used in improved ELISA
and immunoblot tests for routine laboratory diagnosis of natural yersiniosis in humans
and pigs and experimental yersiniosis of rabbits.
 Bacterial-host interactions (invasion, persistence, intracellular survival, as well as the
bioenergetic mechanisms ensuring these processes) were characterized. Pathogenesis
of experimental melioidosis, listeriosis, yersiniosis, salmonelosis, etc. and immune
response of different hosts were established in details.
 Clinical, immunological, and pathomorphological examinations were followed after
experimental oral infections of rabbits with two wild and four genetically constructed
mutant strains of Y. enterocolitica 0:8. A lower virulence and bacterial load of the
viscera, weaker morphological changes, better immunogenicity and well expressed
tissue tropism to the lymphoid tissue of the mutant strains DwzzGB and sodA-314 in
comparison with mutants 8081-R2, DwbcEGB and wild strains WA-314 and 8081-L2
were established.
 The photoinhibitory effect could be used in the practice for photosterilization of
contaminated with enterobacteria water ecosystems;
 The role of Yersinia antigens (LPS) in induction of reactive arthritis was proved in
experimental models.
 The role of outer membrane proteins YopK and YpkA during experimental oral pig
model with Yersinia pseudotuberculosis was studied. It was established that these
mutant strains are less virulent in comparison with wild type strain. Nevertheless the
strains were characterized with high immunogenic potential and ability to colonize the
lymphoid tissues. This ability was the highest in yopK mutant strain.
 The first time in our country was studied the incidence and transmission of multidrugresistant Mycobacterium tuberculosis strains using advanced molecular


epidemiological methods and population structure analysis. The multidrug resistant
and hypervirulent Beijin strain was not found in Bulgaria. The results contribute to
control the global spread of multidrug TB worldwide.
It was found that the methicilin-resistant and methicilin-sensitive strains of
Staphylococcus aureus as well as Pseudomonas aeruginosa and Candida albicans can
be effectively photoinactivated with the cationic phthalocyanine ZnPeMe. Anionic
phtalocyanine ZnPcS and cationic phthalocyanine ZnPeMe are effective virucidal
photosensitisers for the studied DNA-viruses – Herpes virus simplex type I and
Vaccinia virus.
The method of PCR-DGGE was optimized and successfully applied for direct
detection and typing of Campylobacter jejuni and Campylobacter coli in caecal
samples of broilers without preliminary enrichment. This method allows reliable and
fast detection and identification of pathogenic Campylobacters being causative agent
№1 of food infections in humans.