Acta Microbiologica Bulgarica

164-171

Authors: Ivanova, E., Zdravkova, A., Peshev, R.

African swine fever (ASF) is a highly contagious and devastating disease in feral and domestic swine. The infection spreads rapidly through swine farms with clinical signs of high fever 42°C 4-5 days after initiation of the infection followed by dullness, coughing, ocular and nasal discharge, breathing difficulty, cyanosis of the extremities, vomiting, and abortions in pregnant sows. The causative agent of ASF is a large, double-stranded DNA virus of the Asfarviridae family named African swine fever virus (ASFV). ASFV causes haemorrhagic fever in domestic pigs and wild boar, resulting in mortality rates of up to 100%. The disease spreads over a short period of time in many regions of the country. In Bulgaria, the first outbreak of the disease in domestic pigs (backyard, village of Tutrakantsi, Provadiya, Varna district) appeared in August 2018. Later in the same year, 20 new outbreaks in wild boars were recorded in Silistra and Dobrich regions. In 2019, fourteen new cases of ASF in wild boars (WBs) were found, with the last event recorded at the beginning of June 2019 in Alfatar, region Silistra. Later in that year, in July, 16 new outbreaks were found in the Northern part of the country – Pleven, Burgas, V. Tarnovo, Vratca, Russe, Vidin. The situation in Russe region was the worst. The disease was detected in three industrial pig farms – Nikolovo, Brashlen and G. Vranovo. In order to stop the spread of the disease in industrial pig farms, large numbers of pigs were destroyed. The clinical symptoms observed in diseased pigs were typical of ASF infection. Samples investigated by real time PCR were strongly positive (Ct < 30), which was evidence of high quantity of ASFV DNA. Currently, there is no vaccine against ASF and biosecurity measures are the key to prevent the spread of ASF within and among domestic pig farms.

176-181

Authors: Kaftandjieva, A., Stefkova, M., Ivanovska, E., Cekovska, Z.

The aim of the present study was to assess the time-related changes in the microflora of burn wounds in our setting and to determine the susceptibility pattern to commonly used antibiotics. In a period of 8 months a total of 90 burn wound samples (swabs) from 23 hospitalized patients at the Burn Unit were sent for microbiological examination. Swabs were taken weekly in a period of four weeks or until the patients were dismissed from the hospital. Isolation, identification of bacteria and determination of the antimicrobial susceptibility were according to standard microbiological techniques. In the first and second week of hospitalization, the predominant organism was Acinetobacter spp. By the end of the third week, Pseudomonas aeruginosa had become more predominant. In a period of four and more weeks of hospitalization, 7 samples from two patients were positive (yielding double and triple isolates) with further prevalence of Acinetobacter spp. Most of Gram-negative isolates were multidrug-resistant. Acinetobacter spp isolates were resistant as follows: 100% to amoxicillin-clavulanic acid and to cephalosporins, 86.4% to cefepime, 91% to both amynoglycosides, 88.6% to ciprofloxacin and co-trimoxazole, and 84% to piperacillin/ tazobactam and carbapenems. P. aeruginosa isolates were resistant as follows: 100% were resistant to AMC, cefuroxime and cefixime, 95% to co-trimoxazole, from 9% to 40% to cephalosporins, 13.6% to gentamicin,9% to ciprofloxacin, and 4.5% to amikacin and carbapenems. In conclusion, knowledge of the responsible bacterial flora of burn wounds, its prevalence and bacterial resistance, is of crucial importance for fast and reliable therapeutic decisions.

190-199

Authors: Afolabi, F. T., Obisesan, O., Igbinadolor, R. O.

This study aimed at isolating fungi from cocoa pod husks, screen for their ability to degrade cellulose, optimize, produce and purify cellulase. Cocoa pod husks were obtained from Badeku area of Oyo State. The isolates that showed consistent zone of hydrolysis and negative for aflatoxin production were used for cellulase production. Cellulase activity was measured in terms of FPUase and CMCase. A total of 23 fungal isolates were obtained from cocoa pod husk out of which 12 showed a consistent zone of hydrolysis. The fungal isolates were: Aspergillus niger CH2, A. niger CH4, A. flavus CH5, Fusarium oxysporium CH8, A. niger CH10, A. flavus CH13, A. niger CH15, Phytophthora sp. CH16, A. niger CH18, A. niger CH20, A. flavus CH21, A. niger CH23. A. niger CH4 and F. oxysporium CH8 were the isolates used in this study. Incubation time, pH, temperature and substrate concentrations were the parameters used for the optimization of cellulase. The preferred optimized conditions determined for the production of cellulase by A. niger CH4 were 96 hrs, pH 5.5, 30°C and 5% CPH concentration while for F. oxysporium CH8 they were 72 hrs, pH 5.9, 30°C and 4% CPH concentration. Endoglucanase activity was higher in F. oxysporium CH8 while exoglucanase was higher in A. niger CH4. The purification of the ammonium sulphate purified cellulase enzyme using Sephadex G-200 gel filtration increased A. niger CH4 cellulase activity by 1.49-times while that of F. ox¬ysporium CH8 increased by 1.63-times. A. niger CH4 and F. oxysporum CH8 can be used for the production of cellulose.