J Clin Pathol: first published as 10.1136/jcp.36.11.1318 on 1 November 1983. Downloaded from

1318 Technical methods

A mechanised batch screening Quantitative surface viable counts were per- formed on by spreading 10 ,ul of a 1/10 dilu- method for the detection of tion in Ringer's solution over the surface of a CLED . Results P KERFOOT, D McGHIE, E CAHILL, T FOUNTAIN* Department ofClinical Microbiology, Bury General The Figure shows the resulting graph comparing the Hospital, Bury, Lancashire number of colony-forming units (CFU) determined by both methods on urines showing discrete count- able colonies on the multipoint inoculum. In the modem hospital microbiology department, it The calculated line of regression is virtually ideh- is not feasible to investigate fully all routine tical for both Gram-positive and Gram-negative specimens for the detection of bacterial infection of organisms with 10 CFU on the multipoint inoculum the urinary tract. Although increased numbers of being equivalent to a count in the region of 107 leucocytes in the urine may enable selection of CFU/l of urine. urines for comprehensive culture techniques, includ- ing direct sensitivity testing, it is totally Discussion unacceptable to reject any specimen with a normal leucocyte count without performing a screening cul- The blotting paper strip method works well for ture. screening urines containing 108 organisms/1 but is An advance in efficient screening, using blotting less reliable below this level.3 It is now recognised paper strips, was described by Leigh and Williams' that counts of 107 organisms/1 of a pure growth are and is now successfully used in many hospital often of significance in both antenatal and othercopyright. laboratories. patients.45 The mechanical method allows assess- The method now described however, involves the ment of purity of growth between 107 and 5 x 107 mechanical inoculation of 25 urine specimens simul- organisms/l and often above this level. The urines taneously onto an agar surface in a way which not rejected on the basis of the screening test should reduces both time and materials to a minimum. be fully cultured from the original stored urine as, in common with the paper strip method, confusion and Materials and methods delay may occur by working from the colonies of the screening culture.6 The urine specimens studied were preserved The handling of urines in batches of 25 is compat- http://jcp.bmj.com/ immediately using boric acid2 in a 5 ml screw cap ible with the convenient and efficient batch method container, designed initially for paediatric use and for performing urine microscopy, which utilises now produced commercially (Sterilin Ltd, Mid- microtitre plates with flat bottomed wells viewed dlesex, England). through an inverted microscope.7 Twenty-five uncapped urine specimens were placed in a 100 mm square dish divided into com- on September 25, 2021 by guest. Protected partments. The plate acts as a holder which fits on 0 the carriage of a modified multipoint inoculator - 50 |o Gram positive orgQnismns ()LL - Gram negQtive organisms |/ / (Denley, Sussex, England). The inoculator modi- 140 fication was firstly to increase upward lift of the rods c * 0 0o° and secondly to give a suitable spacing to the 5 x 5 3 30 0 0 . W 000 gO0 *~~ configuration. The 25 precision ground steel rods 0 .0oo * inoculate 1 ,ul of each specimen onto the agar sur- >, 20- 000 0 000 I~ 0 face of a 100 mm square dish containing 30 ml * i 10* 0'08. * CLED agar (Oxoid). 0 0 'OS,~oOOsI* a

10 20 30 40 50 *Mr T Fountain's present address is Microbiology Department, Multipoint inoculator (CFU) Tameside General Hospital, Ashton-under-Lyne. Comparison of surface viable count and multipoint Accepted for publication 14 June 1983 inoculator on urines. J Clin Pathol: first published as 10.1136/jcp.36.11.1318 on 1 November 1983. Downloaded from

Technical methods 1319 During the course of one year, the use of the small Little PJ, Peddie BA, Sincock AR. Significance of bacterial and white cell counts in midstream urines. J Clin Pathol containers has been accepted by the nursing staff 1980;33:58-60. without any problems being encountered. Improved 5Maskell R. Current Topics in Infection Series. 3 Urinary tract handling of urine specimens has been achieved; the infection London: Edward Arnold, 1982. mechanical method demonstrating itself as an 6 Stokes EJ, Ridgway GL. Clinical bacteriology 5th ed 1980. efficient labour saving and highly cost effective pro- London: Edward Arnold. 7 Maskeil R. Microbiology of . In: Asscher cedure in the laboratory. AW, ed. The management of urinary tract infecton. Oxford: Medicine Publishing Foundation, 1980:41-50. References ' Leigh DA, Wifliams JD. Method for the detection of significant bacteriuria in large groups of patients. J Clin Pathol 1964;17:489-503. 2 Porter IA, Brodie J. Boric acid preservation of urine samples. Br Med J 1969;ii:353-5. Requests for reprints to: Mr P Kerfoot, Senior MLSO, 3Line SJ, Brookes G. The control and use of bacteruritest strips. Microbiology Department, Bury General Hospital, Wal- Mast Matters 1975;9:11-4. mersley Road, Bury, Lancashire BL9 6PG, England. copyright.

Letters to the Editor

Bone histomorphometri; analysis in famil- Bone histomorphometric analysis shows and surface values are high: this means that ial hypocalciuric hypercalcaemia the presence of a high remodelling state in the number of active osteoblasts is

both patients: relative trabecular resorp- increased although the osteoblastic activity http://jcp.bmj.com/ According to recent publications,' familial tion surface values are slightly but con- is normal at the cellular level as shown by hypocalciuric hypercalcaemia is a relatively stantly raised indicating a stimulation in the normal thickness index of osteoid seams common disease but with as yet unknown osteoclastic resorption activity. Simultane- and mineralisation rate. This histomor- physiopathology. We report here his- ously, relative trabecular osteoid volume phometric profile is similar to hyper- tomorphometric analysis of the bone of a mother and son showing clinical and biological symptoms of the condition: Table Bone histomorphometry in a mot)her and son with familial hypercalcaemia without other features of hypocalciuric hypercalcaemia on September 25, 2021 by guest. Protected familial multiple endocrine neoplasia type 1, hypermagnesaemia, hypocalciuria, nor- Parameters Mother Son mal concentration of parathormone (PTH), and abnormal serum calcium con- Trabecular bone volume (%) 11.0 20-7 centrations after parathyroidectomy. N = 15-3 + 4-6 N = 19-3 + 3-1 Transiliac bone biopsies were performed Relative trabecular resorption 52 5-1 after double labelling with tetracycline. surfaces (%) N = 3-6 + 1-1 N = 3-6 - 1-1 The following histomorphometric para- Relative trabecular osteoid 4-3 13-1 meters were measured: trabecular bone volume (%) N = 1-6 - 0-7 N = 2-7 + 1-3 volume, relative trabecular resorption sur- Relative trabecular osteoid 19-5 63-1 faces, relative trabecular osteoid volume surface (%) N =8-6 - 3.9 N = and 14-4 + 5-9 surfaces, thickness index of osteoid Thickness index of 22-0 20-7 seams, and mineralisation rate. Histomor- osteoid seams (%) N = 18-5 + 2-5 N = 18-9 ± 4-5 phometric results were compared to Mineralisation rate 0 74 0 54 Meunier's normal values. They are shown (gAm/day) N = 0-72 + 0-12 N = 0-72 - 0-12 in the following Table.