CORRELATION BETWEEN ACID PHOSPHATASE AND COAGULASE PRODUCTION OR PHAGE TYPE OF STAPHYLOCOCCUS AUREUS

Development of the novel chromogenic screening medium for methicillin-resistant Staphylococcus aureus

MRSA-chrom, a novel chromogenic screening agar medium for methicillin-resistant Staphylococcus aureus (MRSA), was developed. There were all MRSA strains recovered in 24h as a specific blue-colored colony among 130 microbes including 42 MRSA strains. MRSA-chrom showed the highest detection ratio among 4 commercially available selective media using 50 clinical specimens.

Interrelationship of extracellular enzymes and pseudocapsulation in a strain of Staphylococcus aureus

Sall, Theodore (University of Pennsylvania, Philadelphia, Pa.). Interrelationship of extracellular enzymes and pseudocapsulation in a strain of Staphylococcus aureus. J. Bacteriol. 83:1238-1243. 1962.-A pathogenic strain of Staphylococcus aureus, grown in the presence of a high concentration of lactose, mannitol, and gelatin, produces a great deal of soluble coagulase and a comparatively small amount of gelatinase. Owing to the nature of the growth conditions, the soluble coagulase may be prevented from diffusing into the medium. This results in the formation of a capsulelike structure, which has been termed "pseudocapsule." Presence of soluble coagulase about the cells in vivo might offer some protection to the staphylococci against the humoral and cellular defenses of the host.

OCCURRENCE OF COAGULASE-POSITIVE STAPHYLOCOCCI IN CHEDDAR CHEESE

Samples (13) from several lots of cheddar cheese incriminated in staphylococcal food poisoning and 343 samples of cheddar cheese purchased over a 3-year period in retail markets were examined quantitatively for coagulase-positive staphylococci with the smear plate technique. Of the food-poisoning samples, 11 contained coagulase-positive staphylococci in numbers that ranged from 50 to several million per g. Of the 343 market cheese samples, 20% contained coagulase-positive staphylococci in concentrations ranging from less than 50 to more than 200,000 per g. The phage patterns of 64 of 89 cultures isolated from the food-poisoning samples placed them in the miscellaneous phage group (44A) or in phage group IV and the miscellaneous group (42D/44A); 14 had phage patterns that involved group III, the group with which food poisoning has usually been associated. In contrast, over 50% of 104 cultures from the market cheese, which were typed at 100 times the critical test dilution, had phage patterns that involved group III. Of nine selected cultures isolated from the food-poisoning cheese, three (all in phage group III) were positive for enterotoxin by intravenous injection test of cats.

Influence of water activity on the production of extracellular enzymes by Staphylococcus aureus

Two enterotoxigenic strains of Staphylococcus aureus were examined for their ability to produce a number of extracellular enzymes at various water activity (alphaw) levels. Supernatant, dialyzed culture media were analyzed for total and relative levels of enzyme activity. With the exception of protease, enzyme activity was greatest in spent media obtained from cultures grown at 0.996 alphaw, the highest level tested. Enzyme activity in spent media from an enterotoxin B-producing strain was generally more sensitive to alphaw reduction than activity from an enterotoxin A-producing strain. Unlike the other enzymes assayed, acid and alkaline protease activities were greatest when the organism was grown at 0.94 alphaw.

The identification of staphylococci in clinical and food microbiology laboratories

A comprehensive review of the methods which have been utilized for the identification of staphylococci is presented. Biochemical characteristics which have assisted in the primary isolation of staphylococci, such as pigmentation, hemolytic activity, the egg yolk phenomenon, and deoxyribonuclease and coagulase production, are also analyzed. The potential applicability of advanced techniques to identify staphylococci, such as the detection of enterotoxin production, base ratio analysis, cell wall analysis, phage typing, and serology, is discussed. The following procedures are recommended for routine use: Idnetification of Staphylococcus sp. (clinical laboratories): microscopic observation, catalase activity, coagulase production, lysostaphin sensitivity, and (optional) facultative growth in thioglycolate medium. Identification of Staphylococcus aureus (food laboratories): microscopic observation, catalase activity, coagulase production, thermonuclease production, and (optional) lysostaphin sensitivity.

PHOSPHATASE ACTIVITY OF STAPHYLOCOCCUS AUREUS : CORRELATION OF ENZYME PRODUCTION WITH RESISTANCE TO PENICILLIN AND PHAGE PATTERN

Cannon, Frances D. (The Mary Imogene Bassett Hospital, Cooperstown, N.Y.), and Clinton V. Z. Hawn . Phosphatase activity of Staphylococcus aureus : correlation of enzyme production with resistance to penicillin and phage pattern. J. Bacteriol. 86: 1052–1056. 1963.—A simplified method for the determination of the phosphatase activity in different strains of staphylococci is described. The relationship between phosphatase production and penicillin resistance was studied and found inconstant. A close relationship between phosphatase production and phage group and type was observed.

Some physiological charcteristics of two sets of phage-propagating strains of Staphylococcus aureus

A number of physiological characteristics were studied on some 29 strains of phage-propagating staphylococci belonging to the Basic International Series and the Seto-Wilson bovine-adapted set. All the cultures except strain 73 were coagulase-positive, with reciprocal titers ranging from 2 to 8,192. Strain 73 was again an exception with respect to phosphatase activity. Group 1 yielded high values for both phosphatase and oxygen uptake but low values for extracellular protein. Resistance to penicillin was demonstrated only by strains 80, 81, 53, 54, 75, and 77. Strain 70, one of the highest coagulase producers, alone showed no catalase activity. Mannitol was fermented by all coagulase-positive strains. Hemolysis of one or more of three kinds of erythrocytes (sheep, rabbit, and human) was a common characteristic of most strains. However, pigmentation was a nondiscriminating parameter. Although one-half of the cultures liquefied gelatin, most of them gave similar antibiotic-sensitivity tests, except the six which were penicillinase producers. There was little difference in growth rate for all strains. Comparison of coagulase production to cell size indicated that the high-titer strains were generally larger than the low producers. The foregoing evidence avers that, in addition to lytic spectrum, physiological properties can usefully characterize staphylococcal phage-propagating strains.