The first paper of this series (Hills, 1949) has shown that, in a basal medium in which essential aminoacids are supplied by a gelatin hydrolysate and tyrosine, the rate ofgermination ofspores ofBaciUu8 anthraci8 was greatly increased by boiled yeast extract and that the extract could be replaced by adenosine at a concentration of 10-6m or about 0-25 mg./l. It thus became possible to study the effects of amino-acids on germination, since the optimum concentration expected for many of them, of the order of 100 mg./l. on the basis ofthe optimum concentration of gelatin hydrolysate (0-25 %), was much greater than that of the adenosine. Observations on amino-acid requirements were therefore not likely to be vitiated by trace impurities in the adenosine, which was, necessarily, a natural product.Difficulty was encountered in the study of aminoacid requirements, however, since the synthetic medium for the growth of B. anthracis used by Gladstone (1939), and since modified by Brewer, McCullough, Mills, Roessler, Herbst & Howe (1946) supported a rate ofgermination, even in the presence of yeast extract or adenosine, too small for detection by viable counts, though some germination must have occurred since the strain used grew satisfactorily on the modification of the latter authors. Gladstone (1939) had shown, however, that growth in a modification of his medium containing fourteen amino-acids was inhibited by leucine, isoleucine and valine separately, but was stimulated when these three amino-acids were present in appropriate proportions. In a further simplified medium, containing a total of eleven amino-acids, these three were essential. It seemed possible, therefore, that the feeble germination in synthetic media, and the inhibition of germination which occurred with concentrations of gelatin hydrolysate above the optimal (Hills, 1949), might both be due to an unsuitable balance of amino-acids. Work was therefore begun by attempting to simulate the effect ofexcess gelatin hydrolysate by means of amino-acids, with the hope that this would reveal the cause of failure to germinate in the amino-acid medium. METHODSTechnique. Experimental methods, based on the determination of viable counts by the surface plate technique of Miles & Misra (1938), were as described previously (Hills, 1949). It is again emphasized that all counts were viable counts and the abbreviation (S + V count) is used for the sake of brevity to denote a count determined so as to include both spore and vegetative cells. The period of incubation was 30 min. at 35°, except where otherwise stated.Material,. These were largely ofcommercial origin, but the adenosine and inorganic constituents of the media were purified by recrystallization thrice from water. One specimen of D-alanine was kindly presented by Roche Products Ltd. A second specimen, for which the author thanks Dr H. N. Rydon, was prepared by resolution of the benzoyl derivative of commercial synthetic DL-alanine with brucine, and had[cx] = 7.80 at c, 1-342 g. hydrochloride/100 ml. r-HCI, indica...

SUMMARY: Some chemical requirements for stimulating the germination of spores of a few species of the genus Bacillus were studied by means of viable counts.Of the three compounds ahnine, tyrosine and adenosine, L-ahnine was present in all cases where highly significant stimulation was observed; the need for the other two compounds ranged from ability to dispense completely with both of them to a distinct need for the two together to produce a maximum effect.Generally, the effects were greater with spores grown in a chemically defined amino-acid medium aerated by shaking than with those grown on the surface of a casein-hydrolysate agar.In the single case examined, that of a laboratory strain of B. subtilis, the effect of L-alanine was strongly inhibited D-alanine at a molar ratio of 1 : 30.Previous papers (Hills, 1949a, b) have shown that the germination of spores of a virulent strain of Bacillus anthracis was stimulated by L-alanine, L-tyrosine and adenosine. Germination was strongly inhibited by D-alanine, and this inhibition was abolished by increasing the concentration of the L-isomer. After the discovery that only L-alanine was essential for rapid germination of the spores of a laboratory strain 23. subtilis, a systematic examination of a number of species of the genus Bacillus was undertaken in order to see how far the chemical requirements for germination were common to the genus and how far they could be correlated with classification within the genus. The survey was not completed, but the data now available may be of interest to other workers studying the germination of spores. METHODSStrains used. Most of the work was done with a strain of B. subtilis isolated in this department. A virulent strain of B. anthracis supplied by Dr R. L. (1949 a, b). An avirulent strain of the same species, 84 F 2, was supplied by the Veterinary Laboratory of the Ministry of Agriculture, Weybridge. Other organisms were from the National Collection of Type Cultures (see Table 5). Vollum was that used previously by HillsProduction of spore suspensions. Work with B. subtilis (laboratory strain) was carried out with a stock suspension which had been grown for 48 hr. on CCY agar (Gladstone & Fildes, 1940), heated 90 min. a t 60" at a count of about 1010 spores/ml. and washed thrice with distilled water a t a count of 2 x 109/ml.For comparative work with other organisms, since it was considered that germination might be dependent on the method of cultivation, two different conditions of growth were used with each strain: (a) surface growth on CCY agar; (b) submerged growth, aerated by shaking, in the chemically defined

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Background: Cleaning is a major control component for outbreaks of infection. However, for the SARS-CoV-2 pandemic, there is limited specific guidance regarding the proper disinfection methods that should be used. Methods: We conducted a systematic review of the literature on cleaning, disinfection or decontamination methods in the prevention of SARS-CoV-2. Results: A total of 27 studies were included, reporting a variety of methods with which the effectiveness of interventions were assessed. Virus was inoculated onto different types of material including masks, nasopharyngeal swabs, serum, laboratory plates and simulated saliva, tears or nasal fluid and then interventions were applied in an attempt to eliminate the virus including chemical, ultraviolet (UV) light irradiation, and heat and humidity. At body temperature (37°C) there is evidence that the virus will not be detectable after 2 days but this can be reduced to non-detection at 30 min at 56°C, 15 min at 65°C and 2 min at 98°C. Different experimental methods testing UV light have shown that it can inactivate the virus. Light of 254–365 nm has been used, including simulated sunlight. Many chemical agents including bleach, hand sanitiser, hand wash, soap, ethanol, isopropanol, guandinium thiocynate/t-octylphenoxypolyethoxyethanol, formaldehyde, povidone-iodine, 0.05% chlorhexidine, 0.1% benzalkonium chloride, acidic electrolysed water, Clyraguard copper iodine complex and hydrogen peroxide vapour have been shown to disinfect SARS-CoV-2. Conclusions: Heating, UV light irradiation and chemicals can be used to inactivate SARS-CoV-2 but there is insufficient evidence to support one measure over others in clinical practice.

BackgroundThe number of different antimicrobial recommendations between hospital trusts for the same indication in England is unknown.AimWe aimed to evaluate the heterogeneity of antimicrobial recommendations for seven common inpatient infections across hospital trusts in England and evaluate changes to recommendations following introduction of national (National Institute for Healthcare and Excellence, NICE) and international (WHO) antimicrobial guidelines.MethodsGuidelines published on the MicroGuide smartphone application were collected from December 2017 to February 2018 and re-evaluated between December 2019 and February 2020. The following indications were assessed: community-acquired pneumonia (CAP) CURB65 score ≥3, hospital-acquired pneumonia (HAP), infective exacerbation of chronic obstructive pulmonary disease (iCOPD), cellulitis, uncomplicated urinary tract infection (uUTI), intra-abdominal infection (IAI) and sepsis of unknown source (SUS). On follow-up, compliance against WHO WATCH antibiotic and NICE recommendations was evaluated.ResultsGuidelines were obtained predominantly from England. Antibiotic regimens between hospitals became increasingly diverse across indications in the following order: uUTI, cellulitis, iCOPD, CAP, HAP, IAI and SUS. A piperacillin/tazobactam-based regimen was recommended in HAP (59%), SUS (39%) and IAI (30%). After 2 years, 107 changes were made to 357 antibiotic regimen recommendations; the overall number of regimens using piperacillin–tazobactam and WHO WATCH antibiotics remained similar. Compliance of recommendations with NICE guidelines as follows: iCOPD (100% adherent), uUTI (98%), cellulitis (90%), CAP (43%) and HAP (27%).ConclusionThe heterogeneity of antibiotic recommendations increased as the indicated infection was more severe, with broader underlying bacterial causes. Piperacillin–tazobactam remains favoured in antibiotic regimens, despite not recommended in WHO and NICE guidance.