Acta Microbiologica Bulgarica

194-205

Authors: Nășcuțiu, A-M.

Plants represent the oldest source of pharmacotherapy used by mankind. The medical use of plants strongly evolved over time, being integrated in cultural, philosophical, astrological or mystical systems. Several studies have shown correlations between modern herbal use and the claims provided by ancient European authors like the medieval abbess Hildegard von Bingen or the notorious English herbalist Nicholas Culpeper or by traditional systems (Arabic, Indian, Chinese). About 80% of the population living in the developing countries uses nowadays herbal medicine for treatment. In the developed countries, the current “bio” trend of replacing synthetic drugs with phytotherapy has led to a constant rise of the sales figures of herbal medicines. So far, only a few controlled clinical trials of antibacterial herbal medicines have been published, most of them being methodologically weak. Opening new horizons for the exploration of natural healing sources should be done from the perspectives of safety and efficacy. There is an obvious need for standardization of materials, methods and measures for preparation, preservation and administration of herbal drugs. It is time for the fundamental principles and approaches of the traditional systems to acquire a solid scientific validation. The development of evidence-based phytotherapy will be of much help in the process of evolving from an ideological overestimation of the power of nature to a scientifically proved option for the treatment of many disorders, including infectious diseases.

209-219

Authors: Simeonova, L., Mukova, L., Gegova, G., Galabov, A. S., van der Werf, S.

M2 blockers and neuraminidase inhibitors (NAIs) are two classes of drugs currently approved for prophylaxis and treatment of seasonal influenza A virus infections. The frequency of antiviral drug resistance has increased dramatically over the last 20 years, therefore monitoring of susceptibility to licensed inhibitors should be an essential component of influenza surveillance and therapy in Bulgaria and worldwide. Classical and molecular techniques were used to evaluate the susceptibility of influenza (H1N1) and (H3N2) strains isolated in Bulgaria 2004-2007 to neuraminidase inhibitors and M2 blockers. IC50 values of rimantadine were determined by CPE inhibition in cell cultures. IC50 of NAIs were evaluated fluorimetrically by neuraminidase susceptibility assay with MUNANA substrate. RT-PCR and sequencing were carried out on gene segments HA, NA and M2 with subsequent phylogenetics analysis using the neighbor-joining method and bootstrap analysis. Of the total 26 influenza strains (H1N1) and (H3N2) analyzed, 22 were sensitive and 4 (two H1N1 and two H3N2) were resistant to rimantadine hydrochloride in CPE inhibition assay. 17 isolates were subjected to a fluorescent assay, which showed the IC50 of zanamivir to range from 1.05 nM to 5.28 nM and that of osletamivir IC50 were - from 0.28 nM to 1.31 nM. Sequencing revealed S31N and V27T mutations in transmembrane region of the M2 protein to confer resistance to adamantanes in the A/Sofia/1250 (H3N2) strain. The virus remained susceptible to neuraminidase inhibitors. In all other viruses analyzed no mutations associated with resistance to either M2 blockers or NAIs were found.

227-231

Authors: Hadzhieva, G. P.

Tuberculin skin test is one of the oldest and widely used in vivo methods for detection of Mycobacterium bovis infections in cattle and M. avium infections in birds and pigs. Tuberculins used for the test are purified protein derivatives (PPDs) containing a mixture of antigens - proteins, polypeptides, nucleic acids and polysaccharides. The specificity and activity of PPD depends mainly on the protein content.The aim of the development is to determine the amount of protein in Bulgaria produced dry and liquid PPDs from M. bovis and M. avium by determining the nitrogen content of the micro-Keldahl method. The process occurs in three stages - incineration, distillation and titration. Average losses of PPD tuberculins at various stages of production reached the highest values after sterile filtration, about 25-30%. At a dry substance concentration of 1 mg/ml, we obtained 0.98 mg/ml of protein, while in the non-filtered product the mean amount was 0.80 mg/ml. In a study of dry tuberculins, part of the samples were diluted in order to avoid foaming and to achieve complete burning. The protein losses were about 20%, which may be in the production process, tuberculin drying or in the analysis itself (pipetting, dilution of samples, etc.). Regardless of protein losses during the filtration of liquid unfiltered bovine and avian PPD tuberculins as well as the filtered end product, this process is necessary and of great importance for increasing the content of specific proteins, hence the antigenic activity of produced lots of PPD.

236-239

Authors: Simeonov, K., Chilingirova, M.

The results of the polymerase chain reaction (PCR) and serological testing for Chlamydia abortus and Coxiella burnetii of abortion submissions (placentaе or foetal organ samples) and sera from 56 sheep and 54 goats are presented. The samples were submitted for routine diagnostic procedures at the Laboratory for Chlamydial and Rickettsial Diseases, National Diagnostic and Research Veterinary Medical Institute (NDRVMI), during a five-year period (2013-2018). Samples from 48 sheep and 28 goats were tested by conventional PCR for the presence of one or both infections, while other 34 small ruminants were investigated only serologically by ELISA. In some cases one and the same animal was tested both serologically and by PCR. Of the 43 ovine and 24 caprine samples tested for C. abortus by PCR, positive results were obtained in 24 (35.8%), 18 (41.9%) ovine and 6 (25%) caprine samples, respectively. Five of the 12 PCR-tested goat samples were positive for C. burnetii, whereas no sample of the 17 sheep tested showed presence of this agent. Antibodies against these two intracellular bacteria were detected in 20 (23%) out of 87 sera from aborted animals, suggesting, or confirming their probable etiological role. The results show that C. abortus plays a leading role as a cause of abortions in small ruminants as a whole, but C. burnetii, too, should not be ignored, especially presuming its zoonotic potential.