Total Number Of Viable Bacteria Research Articles

Microbiological Profiling of Imported Apples and Demonstration of Bacterial Survival Capacity through <i>in vitro</i> Challenge Test

Present study conducted a complete investigation on microorganisms contaminating the imported apples commonly consumed in Dhaka metropolis, Bangladesh. Study of microbial prevalence demonstrated a substantial number of total viable bacteria (~107 cfu/g) in each of the dissected portions, i. e., surface, body and core of the samples except for the body and core portion of Malus paulared (Paula Red). Among the specific pathogens, Staphylococcus spp. was found to be predominant within a range of 1.6×105-2.8×107 cfu/g, while Escherichia coli, Klebsiella spp., Salmonella spp., Shigella spp., Pseudomonas spp., Vibrio spp. and Listeria spp. were also identified. Fungal contamination (~106 cfu/g) was observed only in the surface of each of the categories of apple samples tested. Study of antibiogram showed that most of the bacterial isolates were multi-drug resistant (MDR); however, study of antimicrobial activity showed that the Malus pumila (Golden delicious apple) samples possessed the anti-bacterial effect against Vibrio spp. Further studies employing the in vitro challenge test revealed a decline trend in the survival potential of spoiling bacteria in the apple samples tested.

Antimicrobial Effects of Laser-assisted Photodynamic Therapy in Pediatric Endodontic Treatment: A New Clinical Horizon

Aim: The purpose of this study was to compare disinfection of deciduous root canal by conventional chemomechanical debridement (CMD) with sodium hypochlorite (0.5%) vs laserassisted photodynamic therapy (PDT). Materials and methods: Twelve children aged 4 to 7 years with informed consent from their parents were studied. Access cavities were prepared and culture samples were taken before the commencement of the therapy, after CMD using 0.5% sodium hypochlorite and after laser-assisted PDT using methylene blue (MB) dye. Samples were taken by placing a sterile paper cone into the canals and transferring them into brain heart infusion broth. The samples were then subjected for microbiological processing so as to count the total number of viable bacteria. Results: Laser-treated canals showed a reduction in bacterial load by 99.99% as against 83.9% obtained after the use of conventional CMD with sodium hypochlorite. Conclusion: Laser-assisted PDT can be used as an excellent adjunct to CMD to obtain near perfect disinfection of deciduous root canals.

Quality Characteristics of Low-Salt Gochujang Added with Glycyrrhiza uralensis and Brassica juncea

The effects of Glycyrrhiza uralensis and Brassica juncea on the quality and palatability of low-salt gochujang were investigated in terms of the microbial characteristics, enzyme activities, pH, acidity, amino nitrogen and sensory evaluation during 40 days of fermentation. The proliferation of fungi in low-salt gochujang with added G. uralensis and B. juncea were inhibited, while the numbers of total viable bacteria and lactic acid bacteria were not affected. In terms of α-amylase and β-amylase activity, no significant difference was observed by the salt concentration or additives. However, lowering the salt concentration increased protease activity. The amount of amino-nitrogen in low-salt gochujang at 20 days was similar to that in the control gochujang at 40 days. In the sensory test, low-salt gochujang was preferred compared to control gochujang (8.5% salt). Particularly, the 4.3% salt gochujang with additives was the most preferred.

Apis mellifera semen: bacterial contamination and susceptibility to antibiotics

The aims of this study were to identify the bacterial genera and species present in semen of Apis mellifera and to evaluate the sensitivity of those bacteria to different antibiotics. Mesophilic aerobic and microaerophilic bacteria were characterized in semen samples from different hives, and the number of total viable bacteria per milliliter of semen was determined. Twenty-nine isolates were obtained, and 14 different genera were identified, some of them being monomicrobians and others polymicrobians. Colony-forming units (CFU) were variable from no bacterial development up to 4 × 105 CFU/mL. The most frequent genera were Bacillus and Staphylococcus. All the studied isolates were sensitive to gentamicin and amikacin. Spermatozoa viability in sperm samples diluted in buffer with antibiotic was similar to that of pure semen.

The New Methods of Corn Disinfection used in Bioethanol Production

In this study bacterial contamination of corn grains for ethanol fermentation was tested. Microbial pollution is a major problem for distilleries all over the world. The aim of this work was to verify whether chemical agents such as ammonia and propionic acid are efficient in reduction of undesirable microflora in grains. The number of total viable bacteria, lactic acid bacteria, acetic acid bacteria, anaerobic bacteria and the quantity of yeasts and moulds were signified by plate method. The ethanol yield was determined with the use of HP 5890 (Hewlett Packard, USA) gas chromatograph. It occurred that both agents effectively reduce bacterial contamination of corn grains, but fermentation process of propionic acid treated grains no longer proceeds. Thus, ammonia solution is as better disinfection agent for grains used as a raw material for bioethanol production. It may be also useful in disinfection other raw materials to new fermentation technologies which do not require former heating.

Enhanced production of lactic acid with reducing excess sludge by lactate fermentation

The development of a facile technology for utilizing effectively and/or reducing excess sludge is one of the urgent problems since a large quantity of sewage sludge is formed by activated sludge processes. Excess sludge containing 50 mM sucrose was fermented at 50 °C using endogenous bacteria in excess sludge, resulting in a high lactic acid production (8.45 g/L) and in an increased sludge reduction (38.2%). Conversion rate to lactic acid was up to 106.0% by standard fermentation at 50 °C compared to 43.8% at 30 °C and this phenomenon that conversion rate was higher was observed only at 50 °C as the fermentation at less or more than 50 °C had lower conversion rate than that at 50 °C. Lactic acid bacteria increased at 50 °C during 1-d fermentation whereas the number of total viable bacteria only increased slightly, indicating that lactic acid bacteria in sludge at 50 °C were preferentially able to utilize the sucrose for producing lactic acid. Finally, pH-vibration fermentation at 50 °C enabled to completely consume residual sucrose in the normal fermentation, resulting in the maximum production of lactic acid. Lactate fermentation by a purely cultured lactic acid bacterium TS1 with autoclaved excess sludge containing 50 mM sucrose had more than 100% of conversion rate to lactic acid, indicating that a part of sludge was converted into lactic acid during the fermentation. Our technique is useful as a facile engineering for reducing excess sludge concomitantly with producing lactic acid by lactate fermentation.

Viability, diversity and composition of the bacterial community in a high Arctic permafrost soil from Spitsbergen, Northern Norway

The viable and non-viable fractions of the bacterial community in a 2347-year-old permafrost soil from Spitsbergen were subjected to a comprehensive investigation using culture-independent and culture-dependent methods. LIVE/DEAD BacLight staining revealed that 26% of the total number of bacterial cells were viable. Quantitatively, aerobic microcolonies, aerobic colony-forming units and culturable anaerobic bacteria comprised a minor fraction of the total number of viable bacteria, which underlines the necessity for alternative cultivation approaches in bacterial cryobiology. Sulfate reduction was detected at temperatures between -2 degrees C and 29 degrees C while methanogenesis was not detected. Bacterial diversity was high with 162 operational taxonomic units observed from 800 16S rDNA clone sequences. The 158 pure cultures isolated from the permafrost soil affiliated with 29 different bacterial genera, the majority of which have not previously been isolated from permafrost habitats. Most of the strains isolated were affiliated to the genera Cellulomonas and Arthrobacter and several of the pure cultures were closely related to bacteria reported from other cryohabitats. Characterization of viable bacterial communities in permafrost soils is important as it will enable identification of functionally important groups together with the as yet undescribed adaptations that bacteria have evolved for surviving subzero temperatures for millennia.

Short-term Effect of Mastic Gum on Salivary Concentrations of Cariogenic Bacteria in Orthodontic Patients

To determine antibacterial activity of chewing mastic gum against the salivary levels of Streptococcus mutans, the total number of viable bacteria, and lactobacilli in patients undergoing therapy with fixed orthodontic appliances. In this study, the levels of S mutans, lactobacilli, and total cultivated bacteria were measured before and after chewing mastic gum. The antibacterial effects of chewing mastic gum against these microorganisms in saliva were compared with a placebo gum. The counts for orthodontically treated patients were evaluated before chewing gum; just after chewing gum; and after 45, 75, 105, and 135 minutes. Saliva samples taken from the patients were inoculated onto trypticase-yeast-cystine-bacitracin agar for mutans streptococci and onto Rogosa agar for lactobacilli. The agar plates were incubated for 48 hours anaerobically at 37 degrees C. The total number of viable bacteria was then counted. Just after chewing the mastic gum for 15 minutes, a significant decrease of total bacteria and S mutans was observed (P < .001). The reduction in lactobacilli was not significant at later first stage (P > .05). However, at the end of 135 minutes, there were significantly fewer S mutans (P < .001), total viable bacteria (P < .001), and lactobacilli (P < .001) in the oral cavity after chewing mastic gum than after chewing paraffin (P < .001). The results show that chewing mastic gum decreased the total viable bacteria, S mutans, and lactobacilli in saliva in orthodontically treated patients with fixed appliances. Chewing mastic gum might be useful in preventing caries lesions.

In vitro and in vivo antimicrobial effects of mastic chewing gum against Streptococcus mutans and mutans streptococci

Dental caries is associated with oral pathogens and Streptococcus mutans (S. mutans) is one of the primary cariogenic organisms. Mastic gum, from Pistacia lentiscus, has been shown to have antibacterial properties. The objective of this study was to determine antibacterial activity of mastic chewing gum against S. mutans and mutans streptococci in vitro and in vivo conditions. Cukurova University, Dental School, in 2002. Antimicrobial activity of mastic gum was evaluated using standard S. mutans strain by disc diffusion method in vitro. Cytotoxicity effect of mastic gum on HEp-2 cells was evaluated by conventional haemocytometer using the trypan blue exclusion method. Clinical studies were then performed on 25 periodontally healthy volunteers. The inhibitory effect of chewing mastic gum against mutans streptococci in saliva was compared to a placebo gum. Saliva samples were taken from the subjects immediately before and after chewing the mastic gum and the placebo gum for 15 min. Additional saliva samples were collected every 30 min. The samples were inoculated onto mitis salivarius-bacitracin agar and incubated for 48 h anaerobically at 37 degrees C. The total number of viable bacteria was then counted. Among tested solvents (chloroform, acetone, petrolium ether and ethanol), it was found that the acetone was found to be more convenient than the others to dissolve the mastic gum. In the cytotoxicity assay, concentrations up to 75 mg/ml of the mastic gum were not toxic for the replication of HEp-2 cells. Thus, lower concentrations of mastic gum (20 and 50 mg/ml) were used for the experiments. In vitro experiments, the diameters of growth inhibition zones of mastic gum were in the range 9.0-27.0 mm. In the clinical trials, the mean number of bacteria in samples taken after chewing the mastic gum and placebo gum were following; at minute 15 was 112 x 10(4)+/-268 x 10(3) and 175 x 10(4)+/-417 x 10(3)cfu/ml, for minute 45 was 85 x 10(4)+/-219 x 10(3) and 165 x 10(4)+/-329 x 10(3)cfu/ml, at minute 75 was 65 x 10(4)+/-100 x 10(3) and 160 x 10(4)+/-216 x 10(3)cfu/ml, at minute 105 was 60 x 10(4)+/-127 x 10(3) and 150 x 10(4)+/-138 x 10(3)cfu/ml, and at minute 135 was 55 x 10(4)+/-65 x 10(3) and 145 x 10(4)+/-354 x 10(3)cfu/ml, respectively. Significantly fewer bacteria was found in saliva samples collected after chewing mastic gum compared to those after chewing paraffin (p<0.001). This preliminary study showed that mastic gum had significant antibacterial activity against S. mutans and mutans streptococci and it may be a useful adjunct in the prevention of caries.

Sarsaponin Effects on Ruminal Fermentation and Microbes, Methane Production, Digestibility and Blood Metabolites in Steers

The objective of this study was to evaluate the effects of sarsaponin on methane production, ruminal fermentation, nutrient digestion and blood metabolites using three Holstein steers in a 3×3 Latin Square design. The steers were fed Sudangrass hay plus concentrate mixture at a ratio 1.5:1 twice daily, and sarsaponin (0, 0.5 and 1% of DM), which was given at 09:00 and 17:00 h daily by mixing with concentrate. Rumen samples were collected 0, 2, and 5 h after morning dosing. Ruminal pH was numerically decreased and numbers of protozoa were decreased linearly (p<0.01) by treatment. Ruminal ammonia-N was reduced (linear; p<0.05) and total VFA was increased (quadratic; p<0.05) at 2 and 5 h after sarsaponin dosing. The molar proportion of acetate was decreased (quadratic; p<0.05) and propionate was increased (linear; p<0.01) at all sampling times. Blood plasma glucose was increased and urea-N was decreased (linear; p<0.05) at 2 and 5 h after dosing. Methane was decreased by approximately 12.7% (linear; p<0.05). The apparent digestibility of DM and NDF were decreased (quadratic; p<0.05) and that of CP remained unchanged due to the sarsaponin. The numbers of cellulolytic bacteria were decreased (quadratic; p<0.05), while numbers of total viable bacteria remained unchanged due to the sarsaponin. These results show that sarsaponin can partially inhibit rumen methanogenesis in vivo and improve ruminal fermentation, which supports our previous in vitro results. (Asian-Aust. J. Anim. Sci. 2005. Vol 18, No. 12 : 1746-1751)

Aspergilus Oyzae 혹은 Saccharomyces Cerevisiae를 첨가하여 제조한 맥주박 위주 발효사료가 반추위 미생물에 미치는 영향

본 연구는 Aspergillus oryzae(AO) 혹은 Saccharomyces cerevisiae(SC)를 첨가하여 제조한 맥주박 위주 발효사료의 급여가 한우의 반추위내 미생물에 미치는 영향을 조사하기 위해 실시하였다. 공시동물은 반추위 cannula가 장착된 한우 암소 2두를 이용하였다. 시험은 시판 배합사료 <TEX>$715\%$</TEX> 및 corn silage <TEX>$28.5\%$</TEX> 급여구(대조구), 시판 배합사료 <TEX>$45.0\%$</TEX>, AO 첨가 발효사료 <TEX>$26.5\%$</TEX> 및 com silage <TEX>$28.5\%$</TEX> 급여구(TAO)와 시판 배합사료 <TEX>$45.0\%$</TEX>, SC 첨가 발효사료 <TEX>$26.5\%$</TEX> 및 corn silage <TEX>$28.5\%$</TEX> 급여구(TSC)의 3처리구로 구분하여 수행하였다. Total viable bacteria(p<0.05), 혐기성 곰팡이 및 protozoa(p<0.05)의 수는 대조구에 비해 TAO 및 TSC에서 높았다. 단백질 분해 박테리아(p<0.05), 섬유소 분해 박테리아 및 xylan 이용 박테리아 수는 대조구에 비해 TAO 및 TSC구에서 높은 경향이었다 Protozoa의 건물회수율은 대조구에 비해 TAO 및 TSC구에서 높았다(p<0.05). 총 미생물 및 protozoa의 조단백질 함량은 대조구 및 TAO구에 비해 TSC구에서 높았다(p<0.05). 박테리아의 조단백질 함량은 대조구에 비해 TAO 및 TSC구에서 높았다(p<0.05). 총 미생물의 조지방 함량은 대조구 및 TSC구에 비해 TAO구에서 높았으며 (p<0.05), protozoa 및 박테리아의 조지방 함량은 대조구 및 TAO구에 비해 TSC구에서 높았다(p<0.05). 총 미생물의 필수아미노산 비율은 TAO 및 TSC구에 비해 대조구에서 높았다. 박테리아의 methionin 및 alanine 비율은 대조구에 비해 TAO 및 TSC구에서 높았다(p<0.05). 이상의 결과에서 AO 혹은 SC를 첨가하여 제조한 발효사료의 급여는 반추위내 미생물 수 및 균체 조성 변화에 영향을 미치는 것으로 판단된다. This study was conducted to examine effects of brewery meal-based fermented feedstuff supplemented with Aspergillus oryzae(AO) or Saccharomyces cerevisiae(SC) on luminal micro-organism of Korean native cattle. Two cows equipped with luminal cannulas were used as experimental animals. Experiment was done with three treatment groups: <TEX>$71.5\%$</TEX> of commercial feed and <TEX>$28.5\%$</TEX> of com silage(control): <TEX>$45.0\%$</TEX> of commercial feed, <TEX>$26.5\%$</TEX> of fermented feedstuff supplemented with AO and <TEX>$28.5\%$</TEX> of corn silage(TAO): <TEX>$45.0\%$</TEX> of commercial feed, <TEX>$26.5\%$</TEX> of fermented ffedstuff supplemented with SC and <TEX>$28.5\%$</TEX> of corn silage(TSC). The number of total viable bacteria (p<0.05), anaerobic fungi and protozoa(p<0.05) was higher in TAO and TSC than in control. The number of proteolytic bacteria(p<0.05), cellulolytic bacteria and xylan fermenters tended to be higher in TAO and TSC than in control. The dry matter recovery (DMR) of protozoa was higher in TAO and TSC than in control(p<0.05). The crude protein (CP) content of total microbes and protozoa was higher in TSC than in control and TAO (p<0.05). The CP content of bacteria was higher in TAO and TSC than in control(p<0.05). The ether extract(EE) content of the total microbes was higher in TAO than in control and TSC(p<0.05), and the EE of protozoa and bacteria were higher in TSC than in control and TAO(p<0.05). The ratio of essential amino acids of total microbe was higher in control than in TAO and TSC(p<0.05). The ratio of methionine and alanine of bacteria was higher in TAO and TSC than in control(p<0.05). The results suggested that the feeding of fermented feedstuff supplemented with AO or SC had an influence on the numbers of ruminal microorganism and the changes of microbial body composition.

Dynamic response of biofilm to pipe surface and fluid velocity

Biofouling in pipelines is a function of the inner roughness of the specific piping material that is used in distribution systems and the concomitant biofilm formation. To test the effect of velocity on the growth of biofilm, a Roto-Scope was designed and built to imitate different materials and flow conditions in potable water distribution systems. Biofilm formation was monitored using DAPI staining and the total number of viable bacteria. Increased velocity in the system resulted in a specific detaching velocity, where the formation of biofilm was limited. Most of the time these detaching velocities were not the highest velocities tested. The range of detaching velocities was between +/- 3 m x s(-1) and 4 m x s(-1). A flow velocity within this range would thus be ideal for achieving reduced biofilm growth in a distribution system.

Effect of a fibrolytic enzyme preparation from Trichoderma longibrachiatum on the rumen microbial population of dairy cows.

The effects of supplementing a dairy cow diet with incremental levels of a fibrolytic enzyme preparation (preparation B) from Trichoderma longibrachiatum on the rumen microbial population were investigated. Two cows fitted with rumen cannulae were each fed a diet containing barley-based concentrate (52%), maize silage (29%), and chopped alfalfa hay (19%), supplemented with 0, 1, 2, 5, or 10 L of preparation B per tonne of dry matter (DM). Preparation B stimulated numbers of total viable bacteria in a quadratic manner (P < 0.05), to approximately 230, 330, 390, and 250% at 1, 2, 5, and 10 L x t(-1) DM, respectively. Preparation B increased the numbers of cellobiose-utilizing (P < 0.01), xylanolytic (P < 0.05), and amylolytic bacteria (P < 0.05), but had no effect (P > 0.05) on numbers of cellulolytic bacteria. However, when bacterial numbers enumerated on each substrate were expressed as a proportion of total viable bacterial numbers, only cellobiose utilizers were stimulated, and this stimulation was limited to the 1 L x t(-1) DM level of preparation B (P < 0.05). The results of this study demonstrate that the inclusion of an exogenous fibrolytic enzyme preparation in dairy cow diets increased the numbers of rumen bacteria that utilize hemicelluloses and secondary products of cellulose digestion.

Surface pasteurisation of poultry meat using steam at atmospheric pressure

The effects of various steam treatments on the appearance, shelf-life and microbiological quality of chicken portions were investigated. Application of steam at atmospheric pressure (100°C for 10 s) on naturally contaminated chicken breast portions resulted in a 1.65 log 10 cfu cm −2 (S.D. 1.06) reduction in the numbers of total viable bacteria. However, in comparison with untreated controls, this treatment did not extend the shelf-life. Steam treatment for up to 10 s on chicken portions inoculated with a nalidixic acid resistant strain of Escherichia coli serotype O 80 resulted in a maximum reduction of 1.90 log 10 cfu cm −2 (S.D. 0.63). Overall, results indicate that significant reductions in microbiological numbers can be achieved on chicken meat using steam. However, such reductions have little effect on the shelf-life of portioned chicken.

Disinfection of sandpit by steam and changes of bacterial flora after the disinfection

The effect of steam on sandpit disinfection was investigated by supplying steam into sandpits covered with a sheet cover. To evaluate the effect, total number of viable bacteria, number of aerobic sporeforming bacteria, coliforms and fecal coliforms were measured four weeks before, just before, immediately after, two and four weeks after the disinfection. Disinfection of coliforms and fecal coliforms was accomplished when temperature of sand reached more than 60 degrees C. Total number of viable bacteria and number of aerobic sporeforming bacteria also reduced by disinfection with steam. However, after 2 and 4 weeks of disinfection, number of coliforms and fecal coliforms recovered to the same level before disinfection, and total viable count also restored its number. In addition, a significant increase in the number of aerobic sporeforming bacteria was noted both after 2 and 4 weeks of disinfection. These results indicate that the effect of steam disinfection in transient and can not be used for the routine method of disinfection in sandpit.

Changes in the population of some functional groups of rumen bacteria including methanogenic bacteria by changing the rumen ciliates in calves.

Twelve unfaunated male calves aged 5-8 months were inoculated with monogeneric protozoa (Epidinium ecaudatum, Eudiplodinium maggii or Entodinium. spp.) or mixed protozoa population. Thus, five groups of rumen protozoa population were established; Unf (unfaunated, protozoa- free), Epi (Epidinium ecaudatum mono-faunated), Eud (Eudiplodinium maggii mono-faunated), Ent (Entodinium spp. mono-faunated), and Mix (mixed Ophryoscolecids protozoa faunated). The number of total viable bacteria in the rumen was significantly lower in the Epi, Eud and Mix groups than the Unf group. The population of amylolytic bacteria was significantly lower in the Epi group than the Unf group. That of pectinolytic bacteria was higher in the Ent group than the other faunated groups. The number of methanogenic bacteria was significantly higher in the Ent, Eud and Mix groups than Unf, however the Epi group had a lower value than the other faunated groups. The concentration of rumen ammonia-N peaked at 1h after feeding and was significantly higher in the Mix group than in the other groups, and was the lowest in the Unf group. The concentration of rumen volatile fatty acids (VFAs) increased until 2h after feeding. The values of the Unf group were lower than the other groups, but the differences were not significant. The molar proportion of acetate was lowest in the Mix group, highest in the Unf group and the other groups had values intermediate between these two groups. The proportion of butyrate and propionate was lowest in the Unf group.

Influence of peptides, amino acids and urea on microbial activity in the rumen of sheep receiving grass hay and on the growth of rumen bacteria in vitro

The influence of peptides, amino acids and ammonia on the growth and activity of rumen microorganisms was determined in vivo by infusing solutions of peptides, amino acids or ammonia into the rumen and in vitro by adding peptides, amino acids or ammonium sulphate to a nitrogen (N)-free basal growth medium. Four adult sheep were fed grass hay (2% N) at 32 g organic matter (OM) per kg 0.75 body weight, divided into equal meals at 08:00 and 16:00 h. Solutions of enzymic casein hydrolysate (peptides), casein acid hydrolysate + tryptophan, methionine and cysteine (amino acids), and urea were infused into the rumen via a rumen cannula to provide 150 mg N per kg 0.75 body weight daily. Each treatment period was 21 days, and animals received the infusions or an infusion of the same volume of water (20 ml h −1) in a 4 × 4 Latin square design. Rumen pH, numbers of total viable bacteria, cellulolytic bacteria and ciliate protozoa, and volatile fatty acid concentrations were unaffected by the treatments ( P > 0.05), except for the higher and branched-chain acid concentrations which increased ( P < 0.05) when peptides and amino acids were infused. Rumen ammonia concentration increased with all N infusions ( P < 0.05). The degradation of OM of grass hay incubated in nylon bags in the rumen was unaffected ( P > 0.05) by the N infusions. The digestibility of the hay was low (58.6%) and unaffected by the infusions. The flow of microbial protein from the rumen, calculated from the urinary excretion of purine derivatives, was also unaffected ( P > 0.05). In pure cultures, peptides and amino acids stimulated the growth rate of the cellulolytic bacteria, Ruminococcus albus SY3, Ruminococcus flavefaciens 17 and Fibrobacter succinogenes BL2 on cellobiose but not cellulose (Avicel). Peptides showed no benefit over amino acids with the celluloytic bacteria, in contrast to the non-cellulolytic species, Megasphaera elsdenii, Prevotella ruminicola, and Selenomonas ruminantium, whose growth rates were stimulated by more than 70% by peptides in comparison with amino acids. It was concluded that fermentation by rumen bacteria is not limited by the availability of peptides or amino acids when ammonia is available and the growth rate is limited by a slowly degradable energy source.

Adhesion ofHelicobacter pylorito Human Gastric Mucosal Biopsy Specimens Cultivated in Vitro

The therapeutic advances in Helicobacter pylori infection is hampered by the lack of suitable animal model systems. We have previously reported on successful adherence of H. pylori to pig gastric mucosa cultured in vitro. The aim of this study was to verify the technique in human biopsy specimens cultured in vitro. Mucosal samples were taken from H. pylori-negative and H. pylori-positive patients undergoing gastric surgery. The non-infected tissue was infected with H. pylori in vitro, and the infected tissue was put into culture immediately. Total number and those H. pylori firmly attached were checked throughout a 72-h culture. Viability of cultured human gastric mucosa was good and unaffected by the presence of H. pylori. The amount of bacteria adhering, increased with time from 0.01% to 2-4% after 72 h in culture. In vivo-infected specimens initially had a low number of firmly attached H. pylori, but total H. pylori increased with time in culture. It is concluded that human gastric biopsy specimens show good viability for 72 h and that viability and cell division of H. pylori were maintained in both in vivo and in vitro H. pylori-infected tissue. In both cases the total number of viable bacteria attached to the specimens increased with incubation time.

Isolation and identification of staphylococci from milk powders produced in Northern Ireland

Milk powders (37 samples) from five different processing centres (A, B, C, D and E) were examined for total viable counts, total staphylococcal counts and staphylococcal enterotoxins. All powders from centres A, B and C contained low numbers of total viable bacteria and staphylococci but five from centres D and E had high total and staphylococcal counts. Nine different staphylococcal species were encountered in low count powders with a wide range of species occurring at each of the five centres. Three species (Staphylococcus capitis, Staph, saprophyticus and Staph. cohnii) were found whose natural hosts are humans. High count powders all contained added fat of various types and had a much more restricted staphylococcal microflora in which Staph. saprophyticus and Staph. cohnii predominated. None of 384 staphylococcal strains isolated were found to be Staph. aureus. In addition, no enterotoxins were detected.

Influence OfAspergillus oryzaefermentation extract on the fermentation of a basal ration in the rumen simulation technique (Rusitec)

SUMMARYThe effects of adding a culture extract fromAspergillus oryzae(AO) to the fermentation of a basal ration were investigated using the rumen simulation technique (Rusitec). The ration consisted of hay, barley, molasses, fishmeal and a minerals/vitamins mixture, at 500, 299–5, 100, 91 and 9–5 g/kg dry matter respectively. AO eliminated the transient fall in pH that occurred following the addition of substrate to Rusitec, but had no influence on the buffering capacity of the medium. Increases in the acetate: propionate ratio and in the proportion of butyrate in the fermentation products were observed in vessels receiving AO. Ammonia concentrations increased by over 30%. The number of total viable bacteria almost doubled and the cellulolytic population increased three-fold in vessels receiving AO. Protozoal numbers were reduced by almost 45% by AO. The proportion of methane in the headspace gas collected from the vessels during the day was significantly(P&lt; 0·01) lower in vessels receiving AO. These results demonstrate that AO has a marked effect on the microbial population and the stoichiometry of the rumen fermentation, and that these changes can be seen in anin vitrosystem.