Comparison of three selective agars for isolation of campylobacters.
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Agar↗
Biomedical subjects
D Coates
Publications and source records attributed to D Coates.
A comparison of sodium hypochlorite and sodium dichloroisocyanurate products.
A comparison of commercial sodium hypochlorite (NaOCl) and sodium dichloroisocyanurate (NaDCC) products was made. Solutions of NaOCl and NaDCC containing the same levels of available chlorine (av.Cl) exhibited very similar bactericidal activities, despite significant differences in pH. A level of 12.5 ppm av. Cl achieved a greater than 5 log 10 reduction of Staphylococcus aureus in 2 min. A level of 5 ppm av.Cl achieved a greater than 5 log 10 reduction of Pseudomonas aeruginosa in 2 min whilst approximately 100 ppm av.Cl achieved the same reduction in the presence of 1% horse serum, and approximately 200 ppm av.Cl in the presence of 2% horse serum, indicating inactivation levels of around 95 and 97.5% respectively. Tablets of NaDCC were stable but solutions were unstable and decomposed much faster than NaOCl solutions of the same strength. Batch-to-batch variability of different NaOCl and NaDCC products was investigated; whilst NaDCC products always contained the minimum level of av.Cl specified, concentrated NaOCl products sometimes did not due to inherent instability.
Disinfectants↗
The ability of campylobacter media supplements to neutralize photochemically induced toxicity and hydrogen peroxide.
Nutrient agar plates stored in light and air for 48 h became inhibitory for Campylobacter jejuni, C. coli and nalidixic acid-resistant, thermophilic campylobacter (NARTC) strains. All five campylobacter test strains showed greater than 5 log reduction in counts on media which had been stored in light and air. Media stored in the dark and/or in a reduced atmosphere did not become inhibitory and supported the growth of campylobacters. Ferrous sulphate, sodium pyruvate, blood, charcoal or sodium metabisulphite, compounds frequently used as supplements in campylobacter media, were added to nutrient agar prior to storage of media in light and air. All additives except sodium metabisulphite prevented the accumulation of photochemically generated toxic oxygen derivatives and allowed growth of test strains. In qualitative tests to determine the ability of supplements to neutralize hydrogen peroxide, blood was the most active, charcoal and sodium pyruvate slightly less active and ferrous sulphate and sodium metabisulphite the least active. The results of this study confirm that supplements in campylobacter media act as quenching or detoxifying agents and not as enrichment factors.
Campylobacter↗
Blood-free selective medium for isolation of Campylobacter jejuni from feces.
A blood-free selective agar is described which contains charcoal, ferrous sulfate, sodium pyruvate, casein hydrolysates, cefazolin, and sodium deoxycholate (CCD agar). CCD agar was compared with Preston medium for isolation of Campylobacter jejuni from human feces, and isolation rates were similar on both media, but CCD agar was less selective. Temperature studies at 37 and 42 degrees C confirmed that incubation of direct plates at 42 degrees C for 48 h was necessary for maximum isolation of C. jejuni.
Agar↗
A comparison of microaerobic systems for the culture of Campylobacter jejuni and Campylobacter coli.
The relative ability of two commercial gas generating envelopes, the evacuation-replacement technique, and a candle jar, to produce a satisfactory microaerobic atmosphere for the culture of 45 Campylobacter strains on non-selective medium and five selective media (Skirrow's, modified Butzler's Blaser's, Campy-BAP and Preston medium) was investigated quantitatively. A candle jar, and modified Butzler's medium proved to be of limited use. The ability of four commercial gas generating envelopes to produce a satisfactory microaerobic atmosphere in four anaerobic jars of different volume was investigated using five reference Campylobacter strains. Not all of the combinations worked. The oxygen and carbon dioxide concentrations produced in the microaerobic systems studied were measured with gas analysers. The evacuation-replacement technique produced far less variable concentrations of oxygen and carbon dioxide than did the envelopes.
Aerobiosis↗
Development of a blood-free Campylobacter medium: screening tests on basal media and supplements, and the ability of selected supplements to facilitate aerotolerance.
The capacity of six basal media to support the growth of thermophilic campylobacters was tested. The most successful was Nutrient Broth No. 2 (Oxoid) solidified with New Zealand agar but it gave at best only a 9% recovery rate. Various blood products, iron compounds, detoxifying agents, reducing agents, growth stimulants and an antimetabolite were added to the selected basal medium and counts of inoculated organisms were compared with counts on basal medium containing 5% lysed horse blood. Of 22 supplements tried only blood, Fildes' peptic digest of blood, heamatin, iron salts, charcoal, sodium metabisulphite and sodium pyruvate greatly improved the basal medium. The ability of these supplements used singly and in combinations to facilitate aerotolerance of campylobacters was investigated. Two aspects of aerotolerance were tested; (a) the ability of the supplements to sustain the viability of campylobacters seeded onto culture plates left on the bench for up to 6 h before microaerobic incubation; and (b) the ability of the supplements to facilitate the growth of campylobacters at increasing oxygen tension (6, 10 and 17% oxygen). A combination of 0.4% charcoal, 0.025% ferrous sulphate and 0.025% sodium pyruvate was found to be as effective as blood in both tests.
Campylobacter↗
Comparison of selective media for isolation of Campylobacter jejuni/coli.
A comparison of Skirrow's, Butzler's, Blaser's, Campy-BAP and Preston media for Campylobacter spp was made using human, animal and environmental specimens. Butzler's medium gave the lowest isolation rate and Preston medium, which was the most selective, the highest isolation rate. Enrichment culture using Preston enrichment broth gave a higher isolation rate than direct plating onto Preston medium.
Abattoirs↗
A study of the oxygen and carbon dioxide requirements of thermophilic campylobacters.
The oxygen and carbon dioxide requirements of different biotypes of thermophilic campylobacters were investigated by means of (a) quantitative studies, and (b) total growth studies. Oxygen tolerance of the five test organisms differed markedly and varied with the carbon dioxide concentration. At most carbon dioxide concentrations tested, Campylobacter jejuni strains NCTC 11168 and NCTC 11392 tolerated 21% oxygen (growth reduced), C coli NCTC 11353 tolerated 15% oxygen (growth reduced), and C jejuni ATCC 3036 and (nalidixic acid resistant thermophilic campylobacter) NCTC 11352 tolerated 10% oxygen (growth not reduced). Total growth studies indicated that 10% oxygen was the optimal concentration for growth of the five test organisms. All exhibited a requirement for carbon dioxide, and only C jejuni strains NCTC 11168 and NCTC 11392 tolerated its absence (growth reduced), when the oxygen concentration was low. The studies indicated that atmospheres containing 5% to 10% oxygen and 1.0% to 10% carbon dioxide are suitable for growth of the various biotypes of thermophilic campylobacters. The oxygen and carbon dioxide concentrations produced in anaerobic jars by variations of the evacuation-replacement technique were determined and suitable practices identified.
Atmosphere↗
A most probable number method for estimating small numbers of campylobacters in water.
A most probable number (MPN) method capable of estimating as few as ten campylobacters per 100 ml of water is described. The method gave results close to those obtained by the viable count method of Miles, Misra & Irwin (1938) with graded suspensions of Campylobacter jejuni. The method was used to test raw water samples: counts were obtained ranging from 10 to 230 campylobacters per 100 ml for 11 49 coastal and estuary water samples, and from 10 to 36 campylobacters per 100 ml for 7 of 44 river samples. Campylobacters were isolated from an additional 24 of the 'negative' samples by testing 200 ml volumes by glass microfibre filtration and enrichment culture methods. The MPN method should prove to be a useful epidemiological tool particularly suited to the enumeration of campylobacters in particulate fluids.
Campylobacter↗
Use of buffered hypochlorite solution for disinfecting fibrescopes.
The possible use of sodium hypochlorite solution buffered to pH 7.6 and containing 100 ppm available chlorine (avCl) for disinfecting fibrescopes was investigated. A flexible fibrescope experimentally contaminated with Pseudomonas putida, Mycobacterium fortuitum, or Bacillus subtilis spores was effectively disinfected within 10 m in repeatedly and without any observable adverse effect on the instrument. The corrosive nature of buffered hypochlorite was investigated by immersing various fibrescope components and metal wires in solutions of different strength for long periods and examining them for damage. Stainless steel, platinum, glass, Teflon, polythene and epoxy resin were apparently unaffected whereas polyurethane, rubber and other metals tested were damaged to different extents. Buffered hypochlorite solutions may have many applications pertaining to the disinfection of items which are either thermolabile or require rapid effective disinfection.
Bacillus subtilis↗
Effect of pH on sporicidal and microbicidal activity of buffered mixtures of alcohol and sodium hypochlorite.
The effect of pH on the activity of buffered sodium hypochlorite solution, and a buffered methanol/sodium hypochlorite mixture, against Bacillus subtilis spores was investigated. The best results, considering both sporicidal activity and stability, were achieved in the pH range 7.6--8.1. The sporicidal activity and stability of five alcohol/hypochlorite mixtures, each containing a different alcohol and buffered to pH 7.6 and of hypochlorite alone buffered to pH 7.6, were compared. The mixtures were marginally more sporicidal than hypochlorite alone when fresh but were much less stable. An unbuffered methanol/hypochlorite mixture, a methanol/hypochlorite mixture buffered to pH 7.6, and hypochlorite alond buffered to pH 7.6 were all found to be effective against six vegetative organisms and spores of B. subtilis and Clostridium sporogenes. By buffering alcohol/hypochlorite mixtures or hypochlorite solution alone in the pH range 7.6--8.1, high sporicidal activity can be achieved with low concentrations of alcohol and hypochlorite. Such formulations show promise for the disinfection of heat-sensitive medical equipment.
Bacillus subtilis↗
Lottery winners and accident victims: is happiness relative?
Adaptation level theory suggests that both contrast and habituation will operate to prevent the winning of a fortune from elevating happiness as much as might be expected. Contrast with the peak experience of winning should lessen the impact of ordinary pleasures, while habituation should eventually reduce the value of new pleasures made possible by winning. Study 1 compared a sample of 22 major lottery winners with 22 controls and also with a group of 29 paralyzed accident victims who had been interviewed previously. As predicted, lottery winners were not happier than controls and took significantly less pleasure from a series of mundane events. Study 2 indicated that these effects were not due to preexisting differences between people who buy or do not buy lottery tickets or between interviews that made or did not make the lottery salient. Paraplegics also demonstrated a contrast effect, not by enhancing minor pleasures but by idealizing their past, which did not help their present happiness.
Accidents, Traffic↗
Sporicidal activity of mixtures of alcohol and hypochlorite.
In an investigation of the activity against Bacillus subtilis spores of various mixtures of alcohol and sodium hypochlorite 50% methanol with enough hypochlorite to provide 2000 parts per million available chlorine water was the most sporicidal. This mixture, both when freshly prepared and for at least eight hours after mixing, achieved a five-log reduction in spore count in 10 minutes. The sporicidal activity of mixtures containing the same initial level of available chlorine was found to vary with the alcohol, initial alcohol concentration, and age of the mixture. Such mixtures may be useful for disinfecting heat-sensitive instruments.
Alcohols↗
Hygiene of crockery and cutlery from tuberculosis patients [lettes].
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Cooking and Eating Utensils↗
Community care services in Vancouver: initial planning and implementation.
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British Columbia↗
Relationships between estimates of binding of antimicrobial agents by macromolecules, based on physicochemical and microbiological data: cetylpyridinium chloride and polyethylene glycol.
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Anti-Infective Agents, Local↗
Relationship between estimates of binding of antimicrobial agents by macromolecules, bases on physiochemical and microbiological data: benzoic acid and a nonionic surfactant.
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Antifungal Agents↗
The concept of crisis.
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Crisis Intervention↗