Mixed Bacterial Flora Research Articles

PETボトル入り清涼飲料水の直接飲用でボトル内に混入した口腔内常在菌の消長

1996年より国産小容量PET飲料の販売が解除された。2003年における清涼飲料水生産量1,800万kLのうちPET飲料は56%のシェアを占め,その内の36.4%を500mLが占めている。500mL PET飲料が短期間でこれほど普及したのは,小容量PET飲料は,缶と違って再栓ができるという利点から,飲みかけの状態で長時間持ち歩くことが何らかの問題を生じないか,ということを細菌学的観点から検討する研究を行った。(1) PET飲料からの直接飲用により,口腔内に常在する様々な細菌が混入したが,時間経過とともに減少した。(2) 特に,抗菌性をもつと言われている緑茶飲料,ウーロン茶飲料では減少が急速であり,8時間保存後に生菌は認めなかった。(3) 糖類を含む果汁飲料,アミノ酸を含むスポーツ飲料,デンプンを含むむぎ茶飲料では減少が緩慢であり,8時間保存後でも生菌が多く認められた。(4) 通常は複数回の開栓・飲用があり,その都度細菌の暴露を受けるので,生残は多くなるものと考えられる。従って,特にむぎ茶飲料を飲みかけの状態で長時間持ち歩き飲用することにおいては注意が必要である。(5) Staphylococcus属菌は生菌数の減少が急速なウーロン茶飲料や緑茶飲料でも生残しており,減少が緩慢なむぎ茶飲料などではStreptococcus属菌も検出された。

Survival of mixed oral bacterial flora in bottled soft drinks by drinking directly in microaerophilic incubation and the differences between individuals in aerobic incubation

Survival of mixed oral bacterial flora in bottled soft drinks by drinking directly in microaerophilic incubation and the differences between individuals in aerobic incubation

Profiling and identification of eubacteria in the stomach of Mongolian gerbils with and without Helicobacter pylori infection.

Mongolian gerbils are frequently used to study Helicobacter pylori-induced gastritis and its consequences. The presence of an indigenous bacterial flora with suppressive effect on H. pylori may cause difficulties with establishing this experimental model. The aim of the present study was to determine bacterial profiles in the stomach of Mongolian gerbils with and without (controls) H. pylori infection. Gastric tissue from H. pylori ATCC 43504 and CCUG 17874 infected and control animals were subjected to microbial culturing and histology. In addition, gastric mucosal samples from H. pylori ATCC 43504 infected and control animals were analyzed for bacterial profiling by temporal temperature gradient gel electrophoresis (TTGE), cloning and pyrosequencing of 16S rDNA variable V3 region derived PCR amplicons. Oral administration of H. pylori ATCC 43504, but not CCUG 17874, induced colonization and gastric inflammation in the stomach of Mongolian gerbils. Temporal temperature gradient gel electrophoresis (TTGE) and partial 16S rDNA pyrosequencing revealed the presence of DNA representing a mixed bacterial flora in the stomach of both H. pylori ATCC 43504 infected and control animals. In both cases, lactobacilli appeared to be dominant. These findings suggest that indigenous bacteria, particularly lactobacilli, may have an impact on the colonization and growth of H. pylori strains in the stomach of Mongolian gerbils.

Epidemiological, forensic, clinical, and imaging characteristics of head injuries acquired in the suicide attempt with captive bolt gun.

The captive bolt gun (slaughterer's gun) is a tool used in the meat industry for "humane killing" of animals. Used with the intent of suicide, the captive bolt gun causes very serious injuries. We analysed 19 self-inflicted head injuries with captive bolt gun during the past 20 years. Autopsy of 20 pigs killed by this method was also performed. All 19 cases were middle-aged men from rural areas, with low level of education, and without a previous psychiatric history. Five of them used the captive bolt gun daily in their professional activities, while the remaining 14 handled it only sometimes. In seven cases suicide was primarily successful, while in five patients, despite intensive medical care, serious craniocerebral injuries eventually resulted in death. Total mortality was 63.2%. The clinical appearance of the entrance wound and the imaging characteristics of the cranial trauma are very specific, and can be easily differentiated from firearm or other penetrating injuries. These wounds were always primarily infected with mixed bacterial flora from the skin. Therefore, besides radical primary wound care, especially of the wound canal with removal of foreign bodies, it is important to administer high doses of wide spectrum antibiotics.

Hydrogen production from rice winery wastewater in an upflow anaerobic reactor by using mixed anaerobic cultures

Continuous production of hydrogen from the anaerobic acidogenesis of a high-strength rice winery wastewater by a mixed bacterial flora was demonstrated. The experiment was conducted in a 3.0-l upflow reactor to investigate individual effects of hydraulic retention time (HRT) (2– 24 h ), chemical oxygen demand (COD) concentration in wastewater (14– 36 g COD/l), pH (4.5–6.0) and temperature (20–55°C) on bio-hydrogen production from the wastewater. The biogas produced under all test conditions was composed of mostly hydrogen (53–61%) and carbon dioxide (37–45%), but contained no detectable methane. Specific hydrogen production rate increased with wastewater concentration and temperature, but with a decrease in HRT. An optimum hydrogen production rate of 9.33 l H 2/ g VSS d was achieved at an HRT of 2 h , COD of 34 g/ l , pH 5.5 and 55°C. The hydrogen yield was in the range of 1.37– 2.14 mol/ mol-hexose . In addition to acetate, propionate and butyrate, ethanol was also present in the effluent as an aqueous product. The distribution of these compounds in the effluent was more sensitive to wastewater concentration, pH and temperature, but was less sensitive to HRT. This upflow reactor was shown to be a promising biosystem for hydrogen production from high-strength wastewaters by mixed anaerobic cultures.

Association between Tonsillar Core Microflora and Post-tonsillectomy Bacteremia

The aim of the study was to determine whether the population levels of aerobic and anaerobic bacteria in the core tonsils of adults with recurrent acute tonsillitis influence the developmen t of post-tonsillectomy bacteremia. For that purpose we performed qualitative and quantitative bacteriology of 24 excised tonsillar core specimens, together with aerobic and anaerobic perioperative blood cultures. The blood cultures from ten non-surgica l patients with recurrent acute tonsillitis served as controls to determine the occurrence of baseline bacteremia . Post-tonsillectomy bacteremia was found in nine (38%) patients. Isolated bacteria were α -hemolytic streptococci ( n= 2), group C β -hemolytic streptococci ( n= 2), group A b-hemolytic streptococcus (GAS) ( n= 1), Peptostreptococcus sp. ( n =1), Bacteroides sp. ( n= 1) and Prevotella sp. ( n= 2). None of the blood cultures from the controls were positive. Mixed aerobic and anaerobic bacterial flora was found in the tonsil cores from both the patients with blood culture positive or negative results. All blood culture isolates were also recovered in the corresponding tonsillar core, except for the GAS. However , its presence was subsequently demonstrated by PCR. In further analysis, we found no correlation between the bacterial population levels and the developmen t of post-tonsillectomy bacteremia. The absence of GAS growth from the core tonsil of a patient with GAS bacteremia also suggest s that translocation of certain bacteria may occur in spite of low counts. In conclusion, the occurrence of post-tonsillectomy bacteremia is quite frequent in adults and the spectrum of invading agent s is variable. Keywords: post-tonsillectomy bacteremia, tonsil core cultures.

Identification of Helicobacter pylori DNA in Human Cholesterol Gallstones

Background: The gallbladder mucosa secretes hydrogen ions and is covered by mucus. The environmental conditions for bacterial colonization are similar to those in the stomach. Gallbladder stones often contain DNA from enteric bacteria, but no compelling evidence demonstrates that Helicobacter spp. have been present. The aim of this study was to establish bacterial DNA profiles in cholesterol gallstones with special reference to Helicobacter pylori. Methods: Cholesterol gallstones from 20 patients were subjected to polymerase chain reaction, bacterial profiling by temporal temperature gradient gel electrophoresis, automated DNA sequencing, and Southern blot analysis using a Helicobacter sp. specific primer. A nested ureI- PCR assay was used to discriminate between gastric and non-gastric H. pylori. Results: TTGE, partial 16S rDNA sequencing, and hybridization analysis revealed the presence of DNA presumably representing a mixed bacterial flora in cholesterol gallstones, including H. pylori in the gallstone centres in 11 out of 20 patients. In three cases, the ureI -PCR assay revealed non-gastric H. pylori. Conclusions: These data support the presence of DNA from a mixed bacterial population, including H. pylori in cholesterol gallstones, reflecting either that H. pylori is an indigenous part of a flora in the stone-containing gallbladder or, alternatively, that H. pylori colonization in the biliary tract predisposes to cholesterol gallstone formation.

Hydrogen production from organic waste

The extraction of pure hydrogen from the fermentation of household waste by a mixed anaerobic bacterial flora is demonstrated. Simulated household waste (600 g) was fermented in a bioreactor, which was continuously sparged with nitrogen (30 ml/min) fed in from the bottom. The gas stream from the biorector passes through a sulphide trap (ZnO) and then through a heated palladium–silver membrane reactor to separate hydrogen from the gas stream. In this way, waste remediation and biological hydrogen production is combined in a process where a large proportion of the hydrogen produced can be collected, free of other gaseous species from the fermentation.

Bacteriological study of shrimp, Penaeus monodon Fabricius, hatcheries in India

Shrimp hatcheries often face problems of mortality caused by diseases. To understand the bacteriological status of shrimp, Penaeus monodon Fabricius, hatcheries in India, a study of hatchery water at different points was conducted in several hatcheries located along the east and west coast of India. The species composition of the bacterial flora was also determined. The total plate counts of raw sea water on tryptic soya agar ranged from 102 to 104 ml–1, whereas it ranged from 104 to 106 ml–1 in larval tanks. In the larval tanks, the proportion of Vibrio species ranged from 50% to 73%, as compared to 31% in raw sea water. A mixed bacterial flora was observed in hatchery water; however, in the larval tanks, the flora in the larvae was predominantly made up of Vibrio species. A few of the tested Vibrio isolates were non-virulent to shrimp larvae under experimental conditions. Over 90% of the strains were resistant to amoxycillin, ampicillin, cephalexin, cephazolin, cloxacillin and sulphafurazole. Most strains showed sensitivity to tetracycline, chloramphenicol, and quinolones such as norfloxacin and ciprofloxacin.

Isolation of Actinobacillus pleuropneumoniae serotype 2 by immunomagnetic separation

In Denmark porcine pleuropneumonia is most frequently caused by Actinobacillus pleuropneumoniae serotype 2 (60%). Isolation of A. pleuropneumoniae from nasal cavities or tonsils from carrier animals is complicated due to the mixed bacterial flora present. An immunomagnetic separation technique (IMS) using immunomagnetic beads (Dynabeads ®) was developed for isolation of A. pleuropneumoniae serotype 2 from pure cultures and from heterogeneous suspensions. Different coating and washing procedures were evaluated in pure and mixed cultures using polyclonal (PAb) and monoclonal antibodies. The highest reisolation yield was achieved when the beads were coated with 1.5 μg PAb IgG/10 7 beads. After washing the beads for four times 9–24% of the bacteria could be reisolated depending on the amount of IgG attached to the beads and the number of beads used. The recovery was increased to 19–61% when only two washing steps were performed. The IMS was further evaluated using dilutions of A. pleuropneumoniae with added Pasteurella multocida (10 9 CFU/ml). After two washing steps 15% of the A. pleuropneumoniae cells and no P. multocida was reisolated. A detection limit of 10 CFU/ml was found in this heterogeneous suspension. No significant difference was observed when comparing the recovery of A. pleuropneumoniae from pure culture, from mixed cultures and from artificially inoculated tonsils. From 12 pigs inoculated with an aerosol of A. pleuropneumoniae serotype 2 the bacterium could not be detected from the nasal cavity or tonsils by cultivation or PCR 6 weeks later. By using IMS A. pleuropneumoniae serotype 2 could be reisolated from the tonsils of three pigs. The IMS method represents a valuable tool for isolation of A. pleuropneumoniae from tissue samples.

Bacterial Cultures and Bacterial Infection in Open Fractures

Besides the surgical debridement of open fractures, also the prophylactic antibiotic therapy has become a standard procedure. Recently it was hypothesized that this strategy may lead to a selection of more virulent and also antibiotic resistant bacteria which subsequently would result in an increased infection rate over years. In a prospective study bacterial cultures, infection rate and the clinical outcome were examined in 269 open fractures in 230 patients who were admitted to our institution in the years 1993 to 1998. All fractures were treated according to the general principles of open fracture management including antibiotic prophylaxis by the administration of cefazolin 3 time 2g for 3 days starting at the time of surgery. As soon as bacteria were cultured specific antibiotics were applied. According to the Gustilo classification the majority of fractures were scored as Grade O2 followed by O1, O3C, O3A and O3B. In average 78.7% of all open fractures were tested positive for bacterial contamination initially which clearly correlated with the fracture type (24.5% in O1 fractures and 86.8% in O3C fractures ). This bacterial contamination resulted in a mean osteitis rate of 8.2%, again depending on the fracture type. In O1 fractures no case of osteitis was noted, whereas in O3C fractures the osteitis rate was as high as 23.7%. In 21.3% of all open fractures no bacilli were recovered initially but all of these were tested positive in subsequent cultures. But only 3.4% out of these patients sustained a soft tissue infection and no osteitis. The mixed bacterial flora was dominated by Staphylococcus aureus (52.8%), followed by Escherichia coli and Enterobacter (32.5%), Streptococci (26.0%), Pseudomonas (17.1%) and Proteus (1.6%). Other mainly environmental bacteria were present in 30.1%. Despite specific antibiotics the bacterial flora shifted during therapy in the majority of all infections in favor of Staphylococcus aureus, Enterobacter and Pseudomonas. Compared to data in the literature and our institution the infection rate in open fractures based on this study slightly increased especially in O3B and O3C fractures but not yet significantly. There seems to be a shift of cultured bacteria towards hospital acquired pathogens which may explain the increased infection rate, as the percentage of initially bacterial contaminated and not contaminated open fractures stayed almost the same over the years.

Presence of eubacteria in biopsies from Crohn's disease inflammatory lesions as determined by 16S rRNA gene-based PCR.

The aim of this study was to search for putative microbial agents in Crohn's disease (CD) tissues by bacterial broad-range 16S rDNA PCR combined with genus- and species-specific DNA hybridisation analysis. Biopsies taken both surgically and endoscopically from the terminal ileum of 11 CD patients and 11 control patients were investigated. Significant amounts of eubacteria were demonstrated in biopsies taken endoscopically from both affected and unaffected individuals; the biopsies taken at surgery from control patients were negative. Three of five biopsies taken surgically from CD patients harboured Helicobacter spp.-, Mycobacterium paratuberculosis-, Listeria monocytogenes- and Escherichia coli-like 16S rDNA sequences. These findings show the importance of the sampling method chosen when combined with molecular typing of eubacteria in intestinal tissues. The mixed bacterial flora found in the surgical biopsies from CD patients supports the idea that the enteric microflora enters primary lesions where secondary bacterial colonisers may elicit a chronic inflammatory syndrome.

The effect of turbulent flow and surface roughness on biofilm formation in drinking water

There is considerable interest in both Europe and the USA in the effects of microbiological fouling on stainless steels in potable water. However, little is known about the formation and effects of biofilms, on stainless steel in potable water environments, particularly in turbulent flow regimes. Results are presented on the development of biofilms on stainless steel grades 304 and 316 after exposure to potable water at velocities of 0.32, 0.96 and 1.75 m s−1. Cell counts on slides of stainless steel grades 304 and 316 with both 2B (smooth) and 2D (rough) finishes showed viable and total cell counts were higher at the higher flow rates of 0.96 and 1.75 m s−1, compared to a flow rate of 0.32 m s−1. Extracellular polysaccharide levels were not significantly different (P< 0.05) between each flow rate on all stainless steel surfaces studied. higher levels were found at the higher water velocities. the biofilm attached to stainless steel was comprised of a mixed bacterial flora including Acinetobacter sp, Pseudomonas spp, Methylobacterium sp, and Corynebacterium/Arthrobacter spp. Epifluorescence microscopy provided evidence of rod-shaped bacteria and the formation of stands, possibly of extracellular material attached to stainless steel at high flow rates but not at low flow rates.

Activity of Trovafloxacin Against Micro-Organisms Isolated from Diabetic Patients with Lower Extremity Infections

Diabetic foot infections represent a major complication for patients affected by diabetes mellitus. In Ontario, Canada, 45% of all amputations of a lower extremity occur in persons with diabetes.[1] This complication represents a considerable physical, psychological and financial cost. Diabetic foot infections generally involve a mixed bacterial flora, which includes aerobic Gram-positive and Gram-negative bacteria and anaerobic micro-organisms. New quinolones such as trovafloxacin, which has a broad spectrum of activity, may become very useful for treating foot infections in patients with diabetes. Themain objectives of this studywere to determine the in vitro activity of new quinolones against microorganisms isolated from patients with diabetic foot infections, and to compare the activity of new quinolones such as trovafloxacin with antibacterials commonly used in the treatment of such infections.

Omnivory and the stability of simple food webs.

Traditional ecological theory predicts that the stability of simple food webs will decline with an increasing number of trophic levels and increasing amounts of omnivory. These ideas have been tested using protozoans in laboratory microcosms. However, the results are equivocal, and contrary to expectation, omnivory is common in natural food webs. Two recent developments lead us to re-evaluate these predictions using food webs assembled from protists and bacteria. First, recent modelling work suggests that omnivory is actually stabilizing, providing that interactions are not too strong. Second, it is difficult to evaluate the degree of omnivory of some protozoan species without explicit experimental tests. This study used seven species of ciliated protozoa and a mixed bacterial flora to assemble four food webs with two trophic levels, and four webs with three trophic levels. Protist species were assigned a rank for their degree of omnivory using information in the literature and the results of experiments that tested whether the starvation rate of predators was influenced by the amount of bacteria on which they may have fed and whether cannibalism (a form of omnivory) occurred. Consistent with recent modelling work, both bacterivorous and predatory species with higher degrees of omnivory showed more stable dynamics, measured using time until extinction and the temporal variability of population density. Systems with two protist species were less persistent than systems with one protist species, supporting the prediction that longer food chains will be less stable dynamically.

Coexistence and collapse: an experimental investigation of the persistent communities of a protist species pool

1. Using protists in laboratory microcosms we investigated the long‐term coexistence of combinations of species from a six species set to address the following questions: (i) What proportion of the possible communities from the species pool are persistent? (ii) From how many initial states are each of these persistent communities obtained? (iii) What are the impacts of individual species on community collapse? (iv) Can the behaviour of the system be characterized by a simple set of rules? (v) To what extent does knowledge of the results from the pairwise species combinations allow prediction of the outcomes of the more species‐rich sets?2. Replicated microcosms were set up with each of the 63 possible combinations of species from a pool of six protist species (three bacterivores, two predators and one omnivore) along with a mixed bacterial flora. Microcosms were maintained, with nutrient replenishment, for over 100 days until a constant species composition was reached.3. Forty‐seven of the 63 starting combinations showed a repeatable collapse to one of eight communities (including the ‘empty’ community – containing just bacteria). The number of starting combinations leading to each of these persistent communities varied from 17 down to one. Extinction rates were higher in more species‐rich systems.4. The effects of each species in determining the composition of the persistent community were characterized as to whether they were present in the final set or not, and whether their occurrence in the starting combination had any effect on the eventual presence or absence of others. Under this classification the larger species seem to be more influential in shaping the final community.5. The collapse from the initial species composition to that at the end could be stated in terms of four simple rules in 34 of the 47 starting combinations for which a persistent community could be defined.6. Using the outcomes from the single‐species and two‐species starting sets only, the eventual states to which the larger communities collapsed could be correctly predicted in 27 out of the 31 starting combinations containing three or more species for which persistent communities could be defined.

Immunoglobulin- and complement-coated bacteria in pus from peritonsillar abscesses.

Fifty-five samples of pus were collected from 51 acute, non-perforated, two spontaneously ruptured and two recurrent peritonsillar abscesses (35 males and 18 females; median age 18 years) and analysed regarding (i) aerobic and anaerobic bacteria (standard culturing), (ii) morphology of bacteria and inflammatory cells (direct microscopy of acridine orange-stained material), and (iii) the percentage of bacteria coated with immunoglobulins IgG, secretory IgA (SIgA) and IgM and complement cleavage product C3b (immunofluorescence assay). Seventy-one per cent of the abscesses harboured a mixed bacterial flora of various aerobes and anaerobes. In none of the cases with a single bacterial species (27 per cent) could immunoglobulin- or complement-coated bacteria be found. In abscesses with a mixed flora, 18 per cent harboured IgG-coated, 15 per cent SIgA-coated, five per cent IgM-coated and five per cent C3b-coated bacteria, respectively. All pus samples contained inflammatory cells in abundance but they were mostly deformed and only occasionally could intracellular bacteria be recognized. Insufficient immunoglobulin-coating of bacteria might be an important aetiopathogenic factor in the development of a peritonsillar abscess. Bactericide in the abscesses is accomplished chiefly by protective mechanisms not dependent on antigen recognition by antibodies.

Childhood vulvovaginitis and vaginal discharge in general practice.

This study aims to examine the aetiology, clinical features and response to treatment of childhood vulvovaginitis in general practice. A longitudinal survey of consecutive premenarchal patients presenting with vulvovaginitis and/or vaginal discharge in the course of normal consultations with a general practitioner was conducted in a semi-rural, group general practice with 11,000 patients in Plymouth, UK. Forty-two premenarchal girls with vaginal inflammation or discharge were surveyed, with main outcome measures being clinical evaluation, microbiological assessment of urine and vaginal swabs, and patients' and parents' assessments of resolution and relapse of symptoms. Non-specific vulvovaginitis with mixed bacterial flora, associated with poor hygiene and atrophic vaginal mucosa, was the commonest cause; specific bacteria were found in 10 out of 42 cases, including six of Streptococcus pyogenes. No candida was isolated. Treatment with topical oestrogen cream was effective only with mixed infection, oral antibiotics were effective in both mixed and single organisms. No evidence of sexual abuse nor foreign body was found. Childhood vulvovaginitis is not uncommon in general practice, is usually associated with mixed growth of faecal organisms, and is seldom due to serious causes such as sexual abuse or foreign body.

Development and evaluation of a selective and indicative medium for isolation of Actinobacillus pleuropneumoniae from tonsils

In order to isolate Actinobacillus pleuropneumoniae from mixed bacterial flora a selective and indicative medium was developed. The optimal concentrations of antibiotics were determined for selective chocolate agar (S-TSA) and selective blood agar (S-MBA) using a set of 25 strains of A. pleuropneumoniae. Following optimization of the media 96 isolates of A. pleuropneumoniae were tested on S-TSA and S-MBA. For isolation of A. pleuropneumoniae from 101 pig tonsils collected at slaughter the S-MBA proved significantly better than both S-TSA and the two non-selective agars tested. Furthermore, contaminating growth by bacteria other than A. pleuropneumoniae was significantly reduced on S-MBA compared to S-TSA and the two non-selective media.

Orbital cellulitis in children: clinical analysis of 16 cases.

Orbital cellulitis, defined as eyelid erythema and edema, proptosis and/or ophthalmoplegia, with or without visual acuity loss, is a rare, but severe infectious disease. The medical records were reviewed of 16 children, aged 18 years or under, who were admitted at Chang Gung Memorial Hospital with a diagnosis of orbital cellulitis during the period from January 1977 to June 1993. The 16 children included 13 males and 3 females. The mean age of the patients was 5.6 years. Sinusitis, diagnosed clinically and radiologically in eight cases, was the most common predisposing factor. From pus or blood in five patients, these pathogens were isolated: Staphylococcus aureus (2), viridans streptococci (1) and mixed bacterial flora (2). All of the patients were treated with systemic antibiotics. The mean duration of fever after initiation of antibiotic therapy was 2.9 days. Four patients subsequently developed complications: subperiosteal abscess (2), orbital abscess (1), and bacteremia (1). Five patients received surgical treatment. No mortality was reported. After a follow-up period of 1-2 months, no sequelae were found among any of these 16 patients.