Bacterial colonization and endotoxin activity during experimental acute fowl typhoid in chickens.

Bacterial colonization and endotoxin production were investigated before and after experimental Salmonella gallinarum infection in 8-week-old female broiler chickens. These parameters were assayed by means of colony forming units test (CFU) and the Limulus Amebocyte Lysate test (LAL), respectively. Birds were infected per os with 1,5 x 10(9) CFU/ml of wild strain of S. gallinarum isolated from a dead hen. Approximately 1,5 x 10(2); 1,3 x 10(2) and 1,2 x 10(2) CFU of S. gallinarum were recorded from 1 g of liver, 1 g of spleen and 1 ml of blood from the chickens on day 1 post infection. By day 4 corresponding data were 3,7 x 10(4); 4,8 x 10(3) and 1,1 x 10(3) respectively and on day 7 10(5) CFU were present in all three specimen types. The liver and spleen of dead birds were contaminated with more than 10(7) CFU per g. The endotoxin from S. gallinarum was found to have an activity of 1,5; 12,0 and 15,0 endotoxin units (EU)/ml on day 1, 4 and 7 after infection, respectively. No endotoxin activity was established in the blood of the control group (before infection) by the LAL test. This is the first time the connection between the amount of live S. gallinarum in the blood, liver and the circulating level of endotoxin in the blood during the infectious stage of experimental acute fowl typhoid, has been demonstrated.

[Changes in the iron content, erythrocytes and hemoglobin in the blood of poultry with acute experimental fowl typhoid]. / Promeni v sudurzhanieto na zheliazo, eritrotsiti i khemoglobin v kruv na ptitsi s eksperimentalno predizvikan akuten tif.

The dynamic was followed up of the concentration of iron in the blood serum and the liver, of the erythrocyte count, of the haematocrit value of blood, and of the haemoglobin level in chickens of the New Hampshire breed at the age of 300 days, with experimentally induced acute typhoid. It was found that blood serum iron dropped abruptly as early as the second day of infection, whereas the level of iron in the liver rose. The erythrocyte count dropped almost twice as early as the second day following infection, the haematocrit value of the blood following the fluctuations of the erythrocyte count. The haemoglobin level dropped considerably on the third day, with gradually lowering values up to the seventh day. All changes that were recorded with these indices of the blood were found to precede the onset of the first clinical signs of the disease. The values of the haematologic indices with birds that survived came back to normal after the fourteenth day of infection. In the author's personal view leading in the pathogenesis of acute typhoid with the New Hampshire chickens was the lowered amount of serum iron, which disturbed the synthesis of haemoglobin and hence the maturity of erythrocytes, substantiating their lower count. The trophism of vitally important organs and tissues was also found to be disturbed.

[Dynamics of the antibiotic resistance of E. coli strains isolated from cows on 2 dairy farms]. / Dinamika na antibiotikoustoichivostta na shtamove E. coli, izolirani ot kravi v dve kravefermi.

Studied was the dynamic of antibiotic resistance of Escherichia coli strains as isolated from fecal samples taken from 5-day-old calves that had not been offered antibacterial means. The resistance manifested was compared to that of E. coli organisms isolated from calves that had been given antibacterial agents in the course of 36 months as well as to the resistance of E. coli strains isolated from calves at 1, 3, and 5 months of age and from dam cows in the last 12 months of the experiment. A varying period was established for receding of the signs of resistance of the strains to antibiotics--6 months for E. coli to kanamycin and furazolidone, 9 months to tetracycline, chloramphenicol, and gentamycin, and 15 months to streptomycin. Strains isolated from newborn calves on farms with no records of infection were shown to be susceptible to all antibiotics, while those isolated from calves on farms where enteritis was recorded remained polyresistant up to 36 months. No correlation was found between the antibiotic resistance of fecal E. coli strains from the dams and their calves.

[Cocks with experimentally induced acute typhoid]. / Izsledvaniia pri petli s eksperimentalno predizvikan akuten tif.

Acute typhoid infection was induced in cocks of the New Hampshire breed at the age of 14 months within the period of intense productivity. Bacteriologically, there were in the viscera of cocks died of the acute infection organisms of Salmonella gallinarum--the isolates were from the heart, liver, spleen, and testis, while in the viscera of infected birds that were killed no such organisms were isolated. Histologically, there were necrobiotic and degenerative lesions in the epithelial cells of the seminiferous tubuli as well as disturbances in the process of spermiogenesis. The morphologic changes seen in the parenchymal organs were analogous with those that have been demonstrated so far. Cytologically, the semen of the infected cocks presented pathologically changes spermatozoa and anomalies of their head and tail; a large number of erythrocytes and leukocytes were also found.

[Selenium content in the internal organs, musculature and blood of broiler chickens]. / Sudurzhanie na selen v niakoi vutreshni organi, muskulatura i kruv ot pileta-broileri.

Experiments were carried out to establish the presence of selenium in broiler birds at different age, that had been given prophylactically selenium preparations. At the single application of such preparations selenium was found to drop in the liver, kidneys, brain, and blood, and to rise in the breast and femoral muscles. By the end of the fattening period highest was the level of selenium in the organs and tissues with the intake of sodium selenite in the drinking water; it was lowest at the injection of sodium selenite in effective amounts.

[Sensitivity of Listeria strains to drugs and disinfectants]. / Chuvstvitelnost na shchamove listeriia kum lekarstveni i dezinfektsionni sredstva.

Comparative studies were carried out with 8 antibiotics, furazolidon, and 9 disinfection agents with regard to the sensitivity of a total of 14 strains of Listeria monocytogenes. The agents used were the most commonly employed ones in the practice in routinely applied concentrations. It was found that L. monocytogenes strains isolated from sheep had good sensitivity to the action of erythromycin, and penicillin, and were more slightly sensitive to chloramphenicol, gentamycin, tetracycline, and furazolidon. They were resistant to streptomycin and polymixin M. Good disinfection action against L. monocytogenes were shown to have formalin, phesiaform and partly phasiacept. Lower was the effect of sodium hydrate, proserine, and abosanite, while potassium permanganate, creolin, and chloramine did not show any bactericidal action.

[Distribution and characteristics of the R factors in E. coli isolated from poultry]. / Razprostranenie i kharakteristika na R-faktorite pri E. coli, izolirani ot ptitsi.

It has been demonstrated that Escherichia coli organisms isolated from birds in the district of Haskovo are up to 65 per cent resistant to drugs. It has been experimentally shown that the genetic determinants of resistance to chemotherapeutics are transferred via conjugation. The possibility of transferring R-factors from Escherichia coli to Salmonella typhimurium points to one of the routes for the occurrence of drug resistance in Salmonella bacteria.

[Transmissible drug resistance in E. coli isolated from calves]. / Prenosima lekarstvena ustoichivost pri E. coli, izolirani ot teleta.

The study of 30 strains of Escherichia coli, isolated from calves on various farms of the district of Haskovo, revealed that 70.0% of them manifested resistance to drugs. The capacity of calf E. coli organisms of being donors of resistance factors pointed to the episomal nature of their polyresistance. The comparatively readily effected transmission of drug resistance from E. coli isolated from calves was shown to be potential clinical and epizootic hazard. Such animals proved to be carriers and a source of R+ Escherichia coli organisms. It was found that the transmission of drug resistance was not coupled with the transmission of chromosomal inheritance. A high frequency of the drug-resistance transmission phenomenon was established.

[R-factor distribution and characteristics of the E. coli isolated from pigs]. / Razprostranenie i kharakteristika na R-faktorite pri E. coli, izolirani ot praseta.

Studied was the occurrence of the R-factors in Escherichia coli isolated from pigs. It was demonstrated that in 73.3 per cent of the cases drug resistance could be transmitted to Citrobacter. In this instance an occasional drop-out of the markers of resistance to kanamycin, neomycin, ampicillin, tetracycline, and chloramphenicol was observed. In the author's experiments no transmission of the marker of resistance to furazolidon was established. The transmission of the signs of resistance to kanamycin and niomycin as well as to erythromycin and oleandomycin occurred always simultaneously. The possibility of transmitting the drug resistance markers of Escherichia coli to Salmonella typhimurium LT-2 made it reasonable to believe that this is one of the routes for spreading the R-factors among Salmonella organisms. No essential differences were observed between the minimal inhibitory concentration of the donor strains and the level of the acquired resistance with the recombinations. The transmission frequence of the resistance markers proved comparatively high, and ranged from 0.6.10(-3) up to 3.10(-4).

[Experimental transmission of antibiotic resistance in chicks]. / Eksperimentalno prenasiane na antibiotichna ustoichivost pri pileta.

Multi-drug resistance of Salmonella heidelberg was transmitted to normal intestinal flora (E. coli organisms were resistant to ampicillin, streptomycin, tetracycline, erythromycin, and oleandomycin. The donor strains of Salmonella heidelberg used in the experiment was a carrier of the following nine markers of resistance: ampicillin, streptomycin, chloramphenicol, kanamycin, neomycin, novobiocin, tetracycline, erythromycin, and oleandomycin. The donor strains of Salmonella heidelberg used in the experiment was a carrier of the following nine markers of resistance: ampicillin, streptomycin, chloramphenicol, kanamycin, neomycin, novobiocin, tetracycline, erythromycin, and oeandomycin, novobiocin, tetracycline, erythromycin, and oleandomycin. The resistance to drugs was transmitted with the oral administration of the donor strain at the preliminary neutralization of the action of hydrochloric acid in the stomah secretion through sodium bicarbonate (1 cm3 of a 10 per cent sol.) an hour prior to feeding the birds with Salmonella heidelberg (1 cm3 of 10(10). In other experiments carboneum tetrachloratum was injected at rates of 0.08 to 0.15 cm3 (acocrting with the body weight of birds) one day prior to infection, followed by the administration of 0.20 to 0.40 cm3 of a 2 per cent solution of omnopon. Escherichia coli organisms acquired new markers of resistance--to chloramphenicol, kanamycin, neomycin and novobiocin. The level of resistance proved equal with that to the donor strain. A total of 1.8 to 5.4 per cent of the intestinal E. coli investigated proved to be carriers of the indicated markers of resitance. Highest level in acquiring markers of multi-drug resistance (13 per cent) showed E. coli organisms isolated from the liver of birds injected additionally with C. tetrachloratum omnopon.

[Biochemical properties and antibiotic resistance of the staphylococci isolated from cows with subclinical mastitis]. / Biokhimichni svoistva i antibiotikorezistentnost na stafilokoki, izoliranoi ot kravi sus subklikinichen mastit.

A total of 33 strains of staphylococci, isolated from Black Pied cows with subclinical mastitis (conformed by the brom-thymol test), were studied to establish their biochemical properties and resistance to antibiotics as well as the occasional correlation between enzyme activity and resistance. It was found that no such dependences existed so far as the biochemical indices of the investigated strains were concerned. All strains proved strongly sensitive to chrolamphenicol, tylan, kanamycin, neomycin, streptomycin, oleandomycin, erythromycin, ampicillin, and were resistant to tetracycline and polymixin. The resistance of staphylococci to antibodies is probably manifested in connection with some of their biochemical properties. It has been found that resistant strains of staphylococci are more active biochemically.

[Biochemical identification of Salmonella and coli bacteria and their sensitivity to chemotherapeutic agents]. / Biokhimichno identifitsirane na salmoneli i koli-bakterii i chuvstvitelnostta im kum khimioterapevtitsi

Strains of enterobacteria, isolated from pathologic material (dead pigs, birds, lambs, sheep fetuses, swab fecal samples from calves) were biochemically identified by the methods of Costin, Le Minor, and Eming. One-hundred forty of them proved to belong to Escherichia coli and 236 -- to Salmonella. The sensitivity of the isolated bacteria to antibiotics (ampicillin, streptomycin, tetracyclin, kanamycin, neomycin, chloramphenicol, erythromycin, oleandomycin polymyscin), sulfonamides (norsulfasol, sulfaguanidine, and sulfadimesine), and nitrofuran preparations (furazolidon and orafuran) was tested by the disk diffusion method. There was in a high per cent of the cases resistance to tetracyclin, erytromycin, oleandomycin, sulfanilamides, streptomycin, ampicillin, and comparatively well expressed susceptibility to polymyxin, furazolidon, orafuran, kanamycin, neomycin and chloramphenicol. Prevailing were the enterobacteria polyresistant to antibiotics, the observed resistance being expressed to 3, 4, 5, 6, and 7 antibiotics at the same time (out of all nine of them that were studied). The only exception were Salmonella typhimurium and Salmonella dublin which were resistant to 2 or 3 antibiotics only. In connection with the data obtained on the tolerance of enterobacteria to chemotherapeutics it is necessary to reevaluate the programmes for the prophylaxis and control of diseases in farm animals and birds caused by Escherichia coli Salmonella spp.

[Sensitivity of 30 strains of E. coli isolated from calves to chemotherapeutic agents]. / Chuvstvitelnost na 30 shtama E. coli, izolirani ot teleta, kum khimioterapevtitsi

Escherichia coli strains were isolated from calves and were biochemically and serologically identified in terms of their sensitivity to antibiotics. An exclusively high frequency of sensitivity was established to sulfonamides (100 per cent), tetracicline, erythromycin, oleandomycin (86.6 per cent) ampicillin, and streptomycin (70 per cent). Well expressed was their sensitivity to nitrofurans, canamycin, neomycin, and polymyxin. It was demonstrated through serial dilutions that there exists a high level of resistance to sulfanilamides, oleandomycin, erytromycin, tetracycline, streptomycin, chloramphenicol (more than 512 mug/cm3). The prevalence of such polyresistand E. coli strains in calves is the reason for concern in the district of Haskovo.

[Comparative diagnostic studies of epididymitis in rams caused by Brucella ovis]. / Sravnitelni diagnostichni izsledvaniia pri epididimit po kocjovete, predizvikan ot Brucella ovis

Semen samples taken from 21 rams with pronounced pathologic changes were studied in a complex way to establish the etiology contributing to the deterioration of the semen quality. The complement-fixation test was applied with blood serum and semen plasma along with the microscopic study of the semen for the excretion of Brucella ovis organisms and a clinical examination. The following results were obtained: 1. The semen plasma of 90.5 per cent of the rams was positive for Brucella ovis. A total of 80.9 per cent were CFT-positive, and the same per cent of the animals were positive for the excretion of Brucella ovis organisms with the semen. The three diagnostic methods give equally positive results in 84.2 per cent of the cases. 2. The clinical examination revealed gross lesions in the genital apparatus in 33.3 per cent of the investigated animals, which coincided with the results obtained through the above-mentioned three methods in 85.9 per cent of the cases. 3. The simultaneous application of the blood serum and semen CFT, the bacteriologic investigation of the semen, and the clinical examination makes it possible to establish the etiology responsible for the defective spermogram of the rams studied.