A membrane filter-Endo agar method for enumerating Escherichia coli as distinct from other coliforms in drinking water was developed. Membranes containing coliform colonies are transferred to nutrient agar containing 4-methyl umbelliferyl-beta-D-glucuronide (MUG) and incubated at 35 degrees C for 4 h. The MUG is hydrolyzed by the glucuronidase of E. coli and the fluorogenic product is visualized. The method recovered 98% of E. coli without false positives and is proposed as an additional test in routine water examination for the detection of pollution.

From a total of 31319 Shigella strains isolated in Israel between 1990 and 1996, 17574 were sent to the National Shigella Reference Center for typing. Of these, 15287 were identified as Shigella sonnei, 1833 as Shigella flexneri, 327 as Shigella boydii and 127 as Shigella dysenteriae. In all, 4395 strains were tested for sensitivity to ampicillin, trimethoprim-sulfamethoxazole, tetracycline, chloramphenicol, nalidixic acid and ofloxacin. All strains tested were sensitive to ofloxacin, and only three strains were resistant to nalidixic acid. Only 113 of 3240 (3.5%) Shigella sonnei strains, 172 of 970 (17.7%) Shigella flexneri strains and 45 of 185 (24.3%) Shigella boydii strains tested were sensitive to four other antibiotic agents. The rates of resistance of Shigella sonnei, Shigella flexneri and Shigella boydii to trimethoprimsulfamethoxazole were 94.4%, 51.3% and 61.6%, respectively. Rates of resistance to ampicillin among these species were 73.4%, 63.5% and 21.4%, respectively. The proportion of strains exhibiting multiple drug resistance was higher for Shigella sonnei than for the other serotypes studied. These results emphasize the need to reassess the use of antibiotic agents in the treatment of shigellosis.

We describe a simple, cost-efficient, double-selective method for isolation of wild-type poliovirus from sewage samples containing vaccine polioviruses and other enteroviruses, with a detection limit of 18 to 50 PFU per 1 to 2 liters of sewage. By this method we were able to process 1,700 sewage samples collected between 1991 and 1996, from which 10,472 plaques were isolated, 41 of them being identified as wild-type polioviruses.

A microbiological survey of frozen ground meat was conducted during a period of five years, 1975–1980. Five hundred and nineteen samples of frozen ground beef and 172 samples of frozen ground fowl were examined. Bacteriological tests performed included aerobic plate count (APC), Staphylococcus aureus, Streptococcus faecalis and Salmonella. A proposed standard limiting distribution of the various bacteria found in frozen ground meat was proposed. The data indicated that frozen ground fowl was heavily contaminated (33%) with Salmonella, therefore according to our findings, this product should not be processed.

ABSTRACT. Staphylococcus aureus produces an extracellular lipase in a synthetic medium. The composition of the medium affected the amount of enzyme produced: medium containing 2% of peptone was optimal for enzyme production. Tweens added to the media decreased the amount of lipase synthesized depending on the concentration used and the nature of the fatty acid bound to the molecule of polyoxyethylene sorbitan. Carbohydrates that the bacteria could metabolize inhibited lipase production. Bile salts and NaCl decreased the amount of enzyme produced. Optimum lipase production was at pH 7·5 and 37°. The conditions for synthesis of staphylococcal lipase are similar to those described for other bacterial lipases and different from those described for fungi.