SYNOPSIS Although pyelonephritis is a common disease, it escapes clinical detection in an undesirably high proportion of patients. The present unsatisfactory diagnostic position would be much improved by widespread screening of patients by simple yet reasonably accurate methods. Bacterial counts by the pour-plate technique and estimates of the white cell excretion per hour or day, while undoubtedly of diagnostic value, are probably unsuitable for use on a wide scale. In an attempt to find more convenient procedures a simplified stroke-plate method of bacterial counting and a simplified quantitative white cell count method were devised and applied to over 1,000 mid-stream urine samples from 398 patients. Good correlation was obtained between the simpler stroke-plate method of bacterial counting and the more time-consuming pour-plate method. The quantitative white cell procedure was a much more sensitive index of pyuria than wet-film microscopy, and comparison with the bacterial count results showed that it gave a useful indication of urinary infection. It is suggested that a quantitative bacterial count should replace non-quantitative culture methods when urinary infection is suspected and that the quantitative white cell count should be performed as a routine part of the initial clinical and laboratory assessment of all patients, followed by a bacterial count if pyuria is revealed. Experience has shown that routine urine microscopy by a precise method leads to the detection of many cases of occult urinary infection.Estimates of the incidence of pyelonephritis on the basis of necropsy evidence have ranged from 6 18 % (Brod, 1956) to 20% (Rhoads, Billings, and O'Conor, 1952). Many of these cases are undiagnosed, probably because obvious symptoms of urinary tract inflammation, such as dysuria and frequency of micturition, are often absent or slight, particularly if the infection is chronic. Thus, Kleeman, Hewitt, and Guze (1960) report that out of 629 cases of significant pyelonephritis seen at necropsy in a five-year period, only 104 (16.6%) were diagnosed clinically, although they stress that retrospective study of the case records indicated that there was suggestive information in 70% of all cases.

Obesity-Munro et al. MEDICAL JOURNAL adhering strictly to the diet and 2.6 lb. (1.18 kg.) in those deviating from it.The five meals a day diet was acceptable to many patients with " refractory obesity," but the results were satisfactory only in those who adhered strictly to the diet.We wish to thank Miss E. M. Wilson for preparing the diets and for assistance with the study.

No abstract

SYNOPSIS Using a freezing-thawing method for extracting colicine from solid media it has been shown that the choice of media for production and diffusion is important. Digest nutrient agar yielded the most colicine and peptone water agar the least. A factor in bacteriological peptone, but absent in a proteose peptone (Difco) and Neopeptone, was responsible for inhibiting production on peptone water agar. Dextrose reduced the diffusion of colicine. A minimum of six hours' incubation of the colicinogenic organism was required for satisfactory production of colicine.Several methods for demonstrating colicine production have been described since Gratia (1925) first reported the presence of an antibiotic substance produced by Esch. coli on solid media. Fredericq, Thibault, and Gratia (1946) described a stroke plate method which was subsequently modified by Shannon (1957). Chapple (1962) has described a method using electrophoresis. Halbert and Magnuson (1948) describe a method of extracting the colicine from solid media which we have developed to test the differences of colicine production and diffusion on several media. MATERIAL AND METHODPetri dishes containing 20 ml. amounts of the following media were used:DIGEST NUTRIENT AGAR This was prepared from Hartley's broth as described by Mackie and McCartney (1960) Several batches of these media were compared to ensure that there was no variation between batches.Received for publication 12 December 1962. Tryptone soya (see Table 1) was the only medium to show variation between batches both in colicine production and diffusion.The indicator organisms were the Shig. sonnei strains used by Abbott and Shannon (1958

SYNOPSIS Six colicinogenic strains, producing colicine A, B, D, K, S4, and V, showed a variation in the reproducibility of the potency of their crude extracts, although a standard technique was used. The importance of this variation on typing was shown by the effect of different colicine potencies on the patterns of inhibition of the Abbott and Shannon indicators. Using a diffusion technique, 3,004 assays were performed and it was found that the patterns of inhibition depended mainly on the strength of the colicine.A further source of error in typing by production patterns was the sensitivity of the indicator strain. Two sets of indicators from different sources were compared, and though there was agreement in most strains, there were differences which varied from slightly more resistant to totally resistant.It is suggested that the potency of the colicine produced by the colicinogenic strain should be known before typing is performed in order that standard comparisons may be achieved. The precise sensitivity of the indicators should also be confirmed periodically.The interest in colicine production typing by using multiple indicators has been increasing over recent years, and has been applied to the Shigella sonnei and flexneri (Abbott and Shannon, 1958;Gillies, 1964;Hart, 1965); Escherichia coli (Shannon, 1957;Hamon, 1959;McGeachie, 1965); Proteus species (Cradock-Watson, 1965); Klebsiella species (Linton, 1960); and Pseudomonas pyocyanea (Darrell and Wahba, 1964; Wahba, 1965; Osman, 1965;Gillies and Govan, 1966). In most cases the streak method, originally described by Fredericq, Thibault, and Gratia (1946) and subsequently modified by several investigators (Abbott and Shannon, 1958;Gillies, 1964), has been used. We had previously described an agar extraction method (McGeachie and McCormick, 1963;McGeachie, 1965) (Cruickshank, 1969). Peptone water agar for the indicator plates was made as described by Cruickshank (1969). For colicine sensitivity testing equal volumes of a peptone water culture of the indicator organism and 1 % peptone water agar were mixed to give a concentration of 0.5 % seeded agar and poured on the surface of a 1 % peptone water agar base.