Comparative phenotypic characterization of Vibrio cholerae isolates collected from aquatic environments of Georgia.

Vibrio cholerae is ubiquitous in aquatic environment inhabiting marine, fresh and brackish waters. V. cholerae serotypes O1 and O139 cause the devastating diarrheal disease cholera, which is often fatal without proper treatment. Little is known regarding the abundance and diversity of clinically important nonhalophilic vibrios in the South Caucasus region, particularly in Georgia. Here we provide the data on the Georgian environmental strains of V. cholerae isolated in 2006-2009 years from the coastal waters of the Black Sea and inland water reservoirs near Tbilisi. In total, 846 V. cholerae strains were collected from the water samples, most of them (705 strains) obtained from fresh water lakes. Isolation pattern of V. cholerae showed obvious seasonality with the highest isolation rates in late summer - early autumn. Twenty-nine isolates of V. cholerae were attributed to the O1 serotype based on serological studies and PCR identification and were further grouped by biochemical properties into classical and El Tor biotypes as well as hybrids. The study of antibiotic susceptibility profiles for V. cholerae isolates showed that 95% were sensitive to tetracycline, 91% to doxycycline, and 91% to ciprofloxacin. Interestingly, the freshwater isolates appeared to be more resistant to antibiotics than the Black Sea isolates. Among Black Sea isolates of V. cholerae toxigenic strains of O1 serotype revealed higher antibiotic resistance compared to non- O1/non-O139 isolates. In addition, V. cholerae O1 and non- O1/non-O139 isolates differed by phage susceptibility profiles, with higher diversity within the population of environmental non-O1/non-O139 V. cholerae isolates.

Antitumor and adjuvant effects of phagelysates of E.coli in mice with Ehrlich carcinoma.

AIM: To augment anti-tumor host response and overcome the tumor-induced immunosuppression is of paramount importance especially when patient is subjected to radio-/chemotherapy and immune system suffers significantly. Various immunological methods have been employed as supplemental antitumor therapies. We were aimed to investigate the antitumor potential of phagelysates of gram-negative bacteria and their adjuvant effects for conventional chemotherapy in experiment. METHODS: Bacterial phagelysates of E.coli and purified suspensions of corresponding Un bacteriophage were obtained by standard methods of phage research. Experiments were carried out on BL57C/6J mice bearing transplanted Ehrlich carcinoma. Different regimens of phagelysate administration (0,5 ml E. coli phagelysate, 3/8 times with 5 day intervals) and conventional chemotherapy (combination of Doxorubicin 60 mg/m2, Cyclophosphan 800 mg/m(2), Ftoruracil 600 mg/m(2), 3 times with 21 day intervals) were tested. Treatment efficacy was evaluated by tumor growth inhibition percent, index of malignant growth, lifespan and survival percent. RESULTS: Experiments have shown that application of optimal doses of E. coli phagelysate can be well tolerated in mice. No stimulation or support of malignant growth was observed. E. coli phagelysate exhibited significant anticancer effect and adjuvant efficacy. Cancer development was delayed in 65% of inoculated animals in the test group. E. coli phagelysate inhibited tumor growth by 80-90% without apparent side effects. The mice survival was prolonged twice and more. On 65th-69th days of tumor growth in 13% animals complete regression of neoplasms was registered. Application of phagelysates in combination with chemotherapy significantly increased antitumor efficacy of conventional chemotherapeutic drugs. CONCLUSION: Application of bacterial phagelysates can be considered as promising novel strategy in cancer therapeutics.

Microbial water quality of the Georgian coastal zone of the Black Sea.

From 2006 to 2008, microbial water quality was monitored along the Georgian coast of the Black Sea. Temperature, pH, salinity, and dissolved oxygen were measured, along with a variety of aquatic microbial parameters, including heterotrophic plate count (HPC), total culturable bacterial count (TCBC), and chlorophyll a (Chl-a) concentration. Total and fecal coliforms and total enterococci counts were recorded as indicators of fecal pollution. Vibrio bacteria, and Escherichia coli- and Vibrio-specific bacteriophages were isolated and enumerated to determine their relationships to standard marine pollution indicators. Persistent microbial pollution was observed, particularly in the summer months, with a higher rate of contamination in estuaries. Microbial indicators generally showed seasonal dependence, suggesting that temperature may influence bacterial dynamics in this environment. No correlation was apparent between fecal pollution indicators and physical-chemical and aquatic microbial parameters, although there were significant relationships amongst the indicators themselves, as well as with the prevalence of Vibrio bacteria and phage.