The survival of staphylococci within human leukocytes

In a study of the phagocytosis of staphylococci by human leukocytes it has been observed that strains of staphylococci producing human infection were phagocytized by human polymorphonuclear leukocytes in vitro under conditions in which virulent pneumococci, streptococci, or Klebsiella were rarely engulfed. In the presence of human leukocytes in plasma there was a rapid fall in the numbers of viable staphylococci of both pathogenic and non-pathogenic strains, the beginning of which was detectable in 10 to 15 minutes. The fall in culturable pathogenic microorganisms was considerably less marked, however, and a rapid resurgence of growth occurred in 4 to 8 hours, whereas the number of culturable non-pathogenic microorganisms remained low for 18 to 24 hours. These differences appear to be explained by the observation that a significant number of microorganisms of pathogenic strains were able to survive within human leukocytes. Such intracellular survival was found to be associated with evidence of destruction of the leukocytes. In contrast, non-pathogenic strains of staphylococci failed to survive within human polymorphonuclear leukocytes following ingestion.

Phage formation in Staphylococcus muscae cultures. XI. The synthesis of ribonucleic acid, desoxyribonucleic acid, and protein in uninfected bacteria

1. The synthesis of ribonucleic acid, desoxyribomicleic acid, and protein in S. muscae has been studied: (a) during the lag phase, (b) during the early log phase, and (c) while the cells are forming an adaptive enzyme for lactose utilization. 2. During the lag phase there may be a 60 per cent increase in ribonucleic acid and protein and a 50 per cent increase in dry weight without a change in cell count, as determined microscopically, or an increase in turbidity. 3. During this period, the increase in protein closely parallels the increase in ribonucleic acid, in contrast to desoxyribonucleic acid, which begins to be synthesized about 45 minutes after the protein and ribonucleic acid have begun to increase. 4. The RNA N/protein N ratio is proportional to the growth rate of all S. muscae strains studied. 5. While the RNA content per cell during the early log phase depends upon the growth rate, the DNA content per cell is fairly constant irrespective of the growth rate of the cell. 6. Resting cells of S. muscae have approximately the same RNA content per cell irrespective of their prospective growth rate. 7. While the cells are adapting to lactose, during which time there is little or no cellular division, there is never an increase of protein without a simultaneous increase in ribonucleic acid, the RNA N/protein N ratio during these intervals being approximately 0.15. 8. Lactose-adapting cells show a loss of ribonucleic acid. The purines-pyrimidines of the ribonucleic acid can be recovered in the cold 5 per cent trichloroacetic acid fraction, but the ribose component is completely lost from the system. 9. The significance of these results is discussed in relation to the importance of ribonucleic acid for protein synthesis.

Statistical study of the spot-plate technique for viable-cell counts

A statistical study of the spot-plate technique was made for the purpose of establishing an acceptable counting range. The organism used in these studies was Micrococcus lysodeikticus. Standard deviations and coefficients of variation were computed for counts ranging from 20 to 440. The lower and upper limits for acceptable counts, based on coefficients of variation of 10 and 5.8, respectively, were chosen as 100 and 300.

Attempt in classification of catalase-positive staphylococci and micrococci

Mossel, D. A. A. (Central Institute for Nutrition and Food Research T.N.O., Utrecht, The Nethrlands). Attempt in classification of catalase-positive staphylococci and micrococci. J. Bacteriol. 84:1140-1147. 1962.-About 390 strains of Staphylococcus aureus, isolated from clinical material, and about 190 strains of coagulase-negative staphylococci and micrococci from strictly nonclinical habitats were studied by the following recently recommended biochemical tests: anaerobic dissimilation ("fermentation") of mannitol, gelatin liquefaction, type of growth on tellurite-glycine agar, hydrolysis of urea, and KCN tolerance. The latter three tests appeared either not specific for, or not positive for, most S. aureus strains. Virtually all strains of S. aureus were gelatin-positive, but 71% of the other types of cocci also liquefied gelatin. Rapid anaerobic breakdown of mannitol, however, was shown by ca. 95% of the strains of S. aureus, and late fermentation by an additional 3%. Of 105 obligately aerobic coagulase tive cocci (micrococci), none fermented mannitol; of 40 facultatively anaerobic, coagulase-negative cocci (staphylococci), only 7 (18%) fermented mannitol. Oxidative metabolism of mannitol occurred in only three (<1%) strains of S. aureus but was detected in roughly half of the isolates of both groups of coagulase-negative cocci. Pigmentation was confirmed to be of little value, because roughly 50% of both coagulase-positive and -negative strains showed a pale-yellow color on Chapman's mannitol salt agar while 13% of the S. aureus strains tested were white. A key to the classification of catalase-positive cocci consistent with that currently used for Enterobacteriaceae has been based on these figures.

HAEMOPROTEINS AND HAEM SYNTHESIS IN FACULTATIVE PHOTOSYNTHETIC AND DENITRIFYING BACTERIA

1. A simple spectrophotometric method is described for the measurement of various haemoproteins in extracts of photosynthetic and non-photosynthetic bacteria. The method is based on measurements of difference spectra at the Soret maxima. 2. In photosynthetic bacteria of the Athiorhodaceae group the concentration of carbon monoxide-binding haemoprotein and of cytochromes of the b and c types is two to three times as high in anaerobically grown cells as in those grown aerobically. 3. During the adaptation of Rhodopseudomonas spheroides 8253 to form photosynthetic pigments the concentration of each of these haemoproteins increases in parallel with that of the bacteriochlorophyll. 4. The carbon monoxide-binding haemoprotein in aerobically grown Rps. spheroides 8253, in contrast with anaerobically grown cells, is predominantly in the particulate fraction of extracts prepared by ultrasonic vibration. The b- and c-type cytochromes are approximately equally distributed between each fraction in extracts from both types of cell. 5. Extracts of Micrococcus denitrificans grown anaerobically on nitrate contain more cytochromes of the b and c types, as well as of the carbon monoxide-binding pigment, than do those from aerobically grown cells. 6. The activity of ferrochelatase in both Rps. spheroides 8253 and M. denitrificans was similar in extracts from cells grown aerobically and anaerobically, though the haemoprotein content was higher under the latter conditions. Coproporphyrinogen oxidative decarboxylase could not be demonstrated in cell-free extracts of either organism.

SPECTROCHEMICAL ANALYSIS OF INORGANIC ELEMENTS IN BACTERIA

Rouf, M. A. (Washington State University, Pullman). Spectrochemical analysis of inorganic elements in bacteria. J. Bacteriol. 88:1545-1549. 1964.-Quantitative spectrochemical analyses of inorganic elements in the vegetative cells of Escherichia coli, Sphaerotilus natans, Micrococcus roseus, Bacillus cereus, and the spores of B. cereus were made. The following elements were found to be present in the ash samples: B, Na, Mg, Al, Si, P, K, Ca, Ti, Cr, Mn, Fe, Ni, Cu, Zn, Sr, S, Ag, Sn, Ba, Pb, V, and Mo. These could be divided into major, minor, and trace elements, depending on the relative amounts in the cells. Mg, P, K, and S were considered as the major elements; Ca, Fe, Zn, and, perhaps, Cu and Mn as the minor elements, and the rest as trace elements. Mg concentrations were higher in the cells of the gram-positive M. roseus and B. cereus than in the gram-negative E. coli and S. natans. The latter organism contained 2.6% Fe(2)O(3) (dry weight basis). The vegetative cells of B. cereus were higher in Mg, P, K, Na, Ag, and lower in Si, Ca, Zn, Mn, and Cu than were its spores.

STAPHYLOCOCCAL SENSITIZATION: SPECIFIC BIOLOGICAL EFFECTS OF PHAGE K ON THE BACTERIAL CELL WALL IN LYSIS-FROM-WITHOUT

Ralston, Doris J. (University of California, Berkeley). Staphylococcal sensitization: specific biological effects of phage K on the bacterial cell wall in lysis-from-without. J. Bacteriol. 85:1185-1193. 1963.-Phage K, shown previously to sensitize staphylococcal-wall mucopeptide to the action of a phage-induced enzyme, virolysin, was found to act in a specific manner in that its sensitizing effects were restricted to chemical linkages affected by three staphylococcal lysins. These caused an immediate lysis, whereas egg-white lysozyme, which could also digest the wall mucopeptide, exerted variable effects, even when in the absence of phage it produced some lysis. Evidence was presented that the K(1) normal cell autolysin and the K phage virolysin could act synergistically with lysozyme on phage-sensitized cells, and that any effects observed with lysozyme were due to the simultaneous presence of trace amounts of these staphylococcal lysins. None of a series of lysozymelike agents from sea urchins, marine sepunculids, and from rabbit peritoneal histiocytes caused accelerated lysis of phage-sensitized cells, although like lysozyme they showed a slow lysis of phage-free living cells. Other enzymes which did not reduce the turbidity of sensitized cells included agents specific for intracellular components (proteins, lipids, nucleic acids), and enzymes, as decarboxylase, alkaline phosphatase, d-amino oxidase, and hyaluronidase. These results suggested that the main effects of the phage in sensitization were limited to areas of the cell wall involved in protection against the action of the staphylococcal lysins.

FORMATE--PYRUVATE EXCHANGE REACTION IN STREPTOCOCCUS FAECALIS. II. REACTION CONDITIONS FOR CELL EXTRACTS

Oster, M. O. (A. & M. College of Texas, College Station), and N. P. Wood. Formate-pyruvate exchange reaction in Streptococcus faecalis. II. Reaction conditions for cell extracts. J. Bacteriol. 87:104-113. 1964.-In contrast to intact cells of Streptococcus faecalis, no stimulation of the formate-pyruvate exchange reaction was observed in cell extracts when yeast extract was added to the reaction mixture. A heated extract of Micrococcus lactilyticus, vitamin K(5), ferrous sulfate, and ferrous ammonium sulfate stimulated an active exchange by protecting the system from oxygen. Tetrahydrofolate, 2,3-dimercaptopropanol, and sodium sulfide provided partial protection, whereas ascorbate, glutathione, sodium hydrosulfite, ammonium sulfide, and sodium bisulfite gave insufficient protection or were inhibitory. Oxidation-reduction (O-R) indicators were not inhibitory and were used to estimate the O-R potentials of reaction mixtures. A potential at least as negative as -125 mv was estimated to be necessary to preserve or initiate formate-pyruvate exchange activity. The reaction operated over a narrow pH range when strict anaerobic conditions were not maintained but, when the system was suitably poised, the pH range was broader. The influence of high phosphate concentrations was less under strictly anaerobic conditions, and orthophosphate could be replaced by small amounts of pyrophosphate. Effect of temperature, time, and amount of extract is presented. Addition of reduced benzyl viologen and hydrogen-saturated palladium in the buffer during 8 hr of dialysis prevented inactivation of extracts. Recovery of activity could be obtained after ammonium sulfate treatment when a combination of palladium chloride, neutral red, and hydrogen bubbling were used.

ORIGIN OF PALMITIC ACID CARBON IN PALMITATES FORMED FROM HEXADECANE-1-C-14 AND TETRADECANE-1-C-14 BY MICROCOCCUS CERIFICANS

Finnerty, W. R. (University of Iowa, Iowa City), and R. E. Kallio. Origin of palmitic acid carbon in palmitates formed from hexadecane-1-C(14) and tetradecane-1-C(14) by Micrococcus cerificans. J. Bacteriol. 87:1261-1265. 1964.-Degradation of the palmitic acid moiety of cetyl palmitate and myristyl palmitate formed from hexadecane-1-C(14) and tetradecane-1-C(14) by Micrococcus cerificans was carried out. The patterns of C(14) labeling in palmitic acid from cetyl palmitate showed that hexadecane is oxidized at the C(1) position, and cetyl alcohol and palmitic acid thus formed are directly esterified. Palmitic acid arising from tetradecane and esterified to tetradecanol appeared to have been synthesized by the addition of two carbon atoms to an existing 14-carbon atom skeleton. Considerable mixing of C(14) occurred in the C(1) and C(2) positions of palmitic acid thus synthesized.

MICROBIAL ECOLOGY OF ACTIVATED SLUDGE. I. DOMINANT BACTERIA

Over 300 bacterial strains were isolated from seven samples of activated sludge by plating on sewage agar. Gram-negative bacteria of the genera Zoogloea and Comamonas predominated. Many isolates (51%) showed sudanophilic inclusions of poly-beta-hydroxybutyric acid, whereas 34% accumulated iodophilic material on media containing starch. A large number required either vitamins or amino acids, or both, for growth. None of the isolates tested for their ability to bring about changes in autoclaved sewage produced an effluent comparable in quality to the activated sludge control, although the Zoogloea did produce activated sludgelike flocs. A study of 150 bacterial strains isolated from raw sewage revealed that they differed from the sludge isolates in several respects. Coliforms, which constitute nearly a quarter of the sewage isolates, were rarely encountered in sludge.