Staphylococcus epidermidis and other organisms from the skin were found to be the commonest contaminants in 21 samples of human milk donated to a milk bank. Only 2 samples contained enterobacteria; no Phaemolytic streptococci were isolated. Data presented show the difference between bacterial numbers in the first 10 ml and subsequent secretions of milk when drawn sequentially. Refrigerated storage led to the growth of some organisms in the milk; no growth occurred in milk stored at -18OC. A miniaturized resazurin dye test was devised but preliminary observations showed that it had a limited value in detecting rapidly milk of poor bacteriological quality.

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SINCE the first report from this laboratory of the isolation from patients of Staphylococcus aureus cultures resistant to methicillin (Jevons, 196 l), we have carried out a continuous survey of resistance to this antibiotic in cultures sent to us for phage-typing (Jevons, Coe and Parker, 1963; Parker and Jevons, 1964; Dyke, Jevons and Parker, 1966). We used a screening test in which a paper disk impregnated with methicillin was placed on the phage-typing plate. Confirmation of resistance was obtained by repeating the disk test and then measuring the minimum inhibitory concentration (MIC) of methicillin for the cultures in a tube dilution test. Unless the culture showed resistance in all three tests it was considered to be sensitive. It became apparent, however, that these criteria for resistance were somewhat too strict and led to the exclusion of some resistant strains.

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