M.J. Hazen

The sterilization of honey with cobalt 60 gamma radiation: a study of honey spiked with spores ofClostridium botulinum andBacillus subtilis

Unprocessed honey is a recognized wound-healing remedy. However, to make clinical use of honey acceptable, it should be sterile. To find the lowest dose of irradiation needed for sterilization, six batches of honey (a−f) were gamma irradiated with 6, 12, 18, 22 and 25 kGy Cobalt-60. After a dose of 25 kGy the antibacterial activity was not altered. Presumably glucose oxidase (EC 1.1.3.4), which produces hydrogen peroxide, is not easily damaged by irradiation. Amylase activity on the other hand was significantly reduced to 19%, 19%, 21%, 22%, 43% in batchesa), b), c), d) andf) respectively, whereas no decrease was observed in batche). All batches spiked with approximately 106 spores fromCl. botulinum orB. subtilis per 50 g honey proved to be sterile after irradiation with a dose of 25 kGy. Honey was also spiked withCl. botulinum at up to 5000 spores per 50 g honey which is the upper limit of natural contamination. The sterilizing dose in this case was 18 kGy.

Effects of flavophospholipol on resistance in fecal Escherichia coli and enterococci of fattening pigs.

ABSTRACT A “plasmid-curing effect” of multiresistant Escherichia coli by flavophospholipol, an antibiotic used as an antimicrobial growth promoter (AMGP) in animal feeds, has been reported to occur in vitro and in vivo under experimental conditions. In this study, the effect of flavophospholipol under field conditions was studied. The prevalence and degree (proportion of resistant strains to the total numbers present per gram of feces) of resistance of indicator bacteria, E. coli and enterococci, was determined in fecal samples from three groups of pigs that were fed a commercial finisher feed without any AMGP. Group A was the negative control group without any AMGP, group B received the same feed with 9 mg of flavophospholipol/kg of feed (study group), and group C received the same feed with 15 mg of avoparcin/kg (positive control). Fecal samples from each pig were collected at the start and at the end of the study and assessed for the prevalence and degree of resistance against antibiotics commonly used either for therapy in pig medicine or as an AMGP. Before the start of the study, all pigs were colonized with multiresistant E. coli by mixing three resistant pig isolates through their feed after disturbance of the colonization resistance of the intestinal flora by a 3-day course of lincomycin and spectinomycin. At the end of the study, the overall prevalence and degree of resistance of E. coli in the fecal flora had increased significantly in groups A and C but remained at the same level as at the start of the study in group B. The prevalence of vancomycin resistance was 44 and 41% in groups A and B, respectively, but only very low numbers of vancomycin-resistant enterococci (VRE) per gram of feces were found. In the avoparcin-fed group, the prevalence was 72%, and in 57% of the samples, more than 50% of all enterococci present were vancomycin resistant. The prevalence of resistant Enterococcus faecalis increased only in the flavophospholipol-exposed group, from 23% before the start of the study to 43% at the end of the study. It was concluded that flavophospholipol effectively suppressed the augmentation and dissemination of multiresistant E. coli in the intestinal flora of fattening pigs. Avoparcin use strongly selected for VRE carriage and excretion. Therefore, as neither flavophospholipol nor any related molecule is used therapeutically, no cross-resistance with therapeutic antibiotics exists and no transmissible resistance has been shown; the major decrease in resistance in intestinal E. coli of flavophospholipol-fed animals seemed to outweigh the small increase in the risk of transfer of flavophospholipol-resistant E. faecalis from animals to humans via the food chain.

Bacterial contamination of fetal fluids at the time of cesarean section in the cow.

Complications after cesarean section delivery in cattle are mainly the result of infections. The bacteria responsible for this infection can be of exogenous or endogenous origin. In this investigation endogenous contamination was studied. Fetal fluid samples of 23 cows were collected from the uterine cavity during cesarean section just after the removal of the calf, by means of a sterile disposable plastic syringe. The uterine flora was cultured, quantitated and presumptively identified by using selective and elective agarplates. Nineteen samples were positive after culture. Eleven samples contained obligate anaerobic bacteria. When the amniotic sac was broken before the obstetrical examination, the total number of bacteria was significantly higher. Vaginal exploration by the farmer had no significant influence on the number of bacteria encountered. Cesarean section is considered a clean contaminated procedure. One must always take into account that the fetal fluids are contaminated with the endogenous vaginal flora. This leads inevitably to contamination of the wound and the peritoneal cavity. Properly antimicrobial prophylaxis is certainly indicated.

The detection of obligate anaerobic bacteria in udder secretions of dry cattle with mastitis during summer: A comparison between gas-liquid chromatography and bacteriological culturing methods

Udder secretions sampled during the summer in 1984 and 1985 from mastitic quarters of 51 non-lactating cattle, mainly heifers less than 2 years of age, were examined bacteriologically for the presence of (facultative) aerobic and obligate anaerobic bacteria (OAB) and by gas-liquid chromatography (GLC) in order to detect volatile fatty acids (VFA), metabolic end-products of OAB. Forty-nine samples yielded positive cultures and in 20 cases these were mixtures of (facultative) aerobes and OAB. Only two specimens appeared to be sterile and from one specimen only were OAB cultured. Corynebacterium pyogenes was isolated from 35% of the cases and Peptococcus indolicus and Fusobacterium necrophorum from 31 and 22%, respectively. In most specimens (19/21) which yielded OAB after culturing, VFA (C3-C6) could be detected by GLC. Detection of VFA in summer mastitis secretions appeared to be a useful technique to evaluate the importance and association of OAB with summer mastitis. Because samples can be easily collected and stored at -20 degrees C, this is especially advantageous in situations where adequate facilities for the isolation of OAB are not readily available.

Effects of calcisorb on fecal bile acids and fatty acids in human volunteers

The intake of calcium (Ca) is negatively associated with colorectal cancer (crc) risk. The aim of this study was to investigate in a double-blind, placebo-controlled trial, the effects of the Ca-binder Calcisorb, which is given to kidney stone patients with hypercalciuria type I, on risk factors for crc risk, bile acids (BA), and long-chain fatty acids (LCFA) in fecal water. Results show that the concentration of BA and LCFA in fecal water did not change, although the urinary excretion of Ca and magnesium (Mg) and the concentration of Ca and magnesium in fecal water decreased. The daily excretion of BA and LCFA acids decreased significantly (p < 0.05) during the Calcisorb period. In conclusion, binding dietary Ca and Mg with Calcisorb from a diet with a relatively low amount of fat does not enhance the solubility of BA and LCFA in fecal water.

A bacteriological evaluation of three methods of bowel preparation for elective colorectal surgery.

The preparation of the gastrointestinal tract for elective colorectal surgery is still a controversial issue (Hirschmann and Inui, 1980). The conventional preparation consists of dietary restriction, mechanical cleansing with cathartics and enemas, and often administration of antibiotics. In 1973, Cox et al. described Whole Gut Irrigation (WGI) as an economic, rapid and more efficient alternative method for mechanical cleansing of the bowel. With this method, a nasogastric tube is passed into the stomach and an isotonic irrigation fluid is introduced through this tube (50-75 ml/min), while the patient is seated on a special toilet. The WGI continues till the rectal fluid becomes clear. This takes about 10-20 1 irrigation fluid over a period of 2~4 h. To compare this new method with the conventional bowel preparation a prospective randomised study was performed in 3 groups of patients. All patients eligible for elective colorectal surgery were included and at random divided into 3 groups. The first group (Cony.) was prepared for 3 days by the conventional method and then received 3 • 1 g neomycin and 3 x 0.5 g metronidazole. Group 2 (WGI) was prepared by whole gut irrigation and group 3 (WGI + A ) by whole gut irrigation with antibiotics (1 g/1 neomycin and 0.5 g/1

The detection of obligate anaerobic bacteria in swine abscesses. A comparison between gas-liquid chromatography and bacteriological culturing methods.

From the 62 swine abscesses examined, 56 yielded positive cultures, of which 38 cases were mixtures of facultative aerobes and obligate anaerobic bacteria (OAB). Only 6 species appeared to be sterile. In all specimens, which yielded OAB, VFA (C4-C6) could be detected by gas-liquid chromatography (GLC). False negatives were not recorded, and only one false positive was found, which might have been due to faulty culture technique, or to the fact that the metabolic markers may persist longer than the OAB themselves. Because current methods to isolate non-sporulating OAB are laborious and not available in most veterinary clinical situations and because there is a need to evaluate the importance of non-sporulating OAB in veterinary medicine, GLC seems to be a useful alternative to culture techniques for detecting the presence of OAB in infectious processes in animals.