An L-form of Staphylococcus aureus adapted to a brain heart infusion medium without osmotic stabilizers

An L-form derived from halotolerant Staphylococcus aureus Tasaki was adapted to growth in a brain heart infusion medium without any supplemental osmotically protective solutes (360 mOsm/kg). This L-form had no chemically detectable peptidoglycan residues on its surface. Electron microscopic observations confirmed morphologically the absence of the structures and also of other osmotically protective polymers within or exterior to the cytoplasmic membrane. The osmotic stability and susceptibility to bacitracin, D-cycloserine, and vancomycin of the L-form adapted to growth in 360 mOsm osmotically unprotective medium was higher than that of the L-form grown in 1,950 mOsm supplemented with 4.5% NaCl. The adapted L-form tended to be more sensitive to almost all of the antibiotics examined, other than the inhibitors for cell wall-synthesis, than the original L-form strain requiring osmotic protection for growth. Chemical analysis of the membrane of the adapted L-form indicated 16.3% total lipids and 20.6% proteins by dry weight of the membrane, and it contained larger amounts of lipid phosphorus (20.0 microgram/mg).

Mitogenic effect of cytoplasmic membranes and a cytoplasmic fraction of Staphylococcus aureus L-forms on human peripheral blood lymphocytes

The cytoplasmic membranes and a cytoplasmic fraction of Staphylococcus aureus L-forms increased the incorporation of [3H]thymidine by human lymphocytes in the presence of fetal bovine serum. Both fractions stimulated cord blood lymphocytes as well as adult peripheral lymphocytes, suggesting the possibility that the observed effect was not due to an antigen-specific reaction, but to an immunologically nonspecific action. The membrane mitogen(s) was resistant to trypsin, although it was partially solubilized by trypsin treatment. The mitogen(s) could not be extracted with a chloroform-methanol mixture (2:1, v/v), although the chloroform-methanol soluble fraction was strongly mitogenic to murine splenocytes. Human serum which was added to the assay system in place of fetal bovine serum definitely suppressed the mitogenic effect of both cytoplasmic membranes and the cytoplasmic fraction, especially the latter.

Serum albumin as an auxiliary factor enhancing compact-colony formation by Staphylococcus aureus in serum-soft agar

Serum albumin was identified as an auxiliary factor enhancing the substance active in compact-colony formation by strains of S. aureus when cultivated in serum-soft agar.

Chemotaxigenesis by encapsulated Staphylococcus aureus M

Although encapsulated Staphylococcus aureus M is not opsonized by normal human serum, as a chemotaxigen this organism behaved similarly to an unencapsulated variant strain. For optimal chemotaxigenesis, an intact classical complement pathway was required, and C5a appeared to be the major chemotaxin.

Activated silver coatings for surgical implants

Increase in current from 1.8 to 3 and then to 9 microAH+DC/cm2 controlled respectively 25%, 37%, and 69% of S aureus on intramedullary silver pins (too soft in practice) in femurs of rabbits. Then optimal current of 12 muAH+DC/cm2 was used. On stainless steel pins with intramedullary injection of AgCl or AgNO3, a 25% or 64% bacterial control was achieved. Stainless steel pin, silver electroplated or electroplated and chloridized gave 85% and 91% bacterial control. One hundred percent of the bacteria was eliminated with stainless steel pins coated with 100 monomolecular layers of silver stearate.

Effect of glucose and oxygen on the structure of the plasma membrane of Staphylococcus aureus

The effects of glucose and oxygen on the formation of the plasma membrane of Staphylococcus aureus were studied. Phospholipids were consistent components of the membrane and were not affected by glucose or oxygen. Phospholipid fatty acids in cells grown in glucose containing media were rich in Ceven (C18, C20) fatty acid chains, whereas cells grown in glucose deficient media (normal broth) had anteiso Codd (C15,C17) fatty acid chains in place of Ceven chains. This may indicate increased membrane rigidity of the cells grown in glucose containing media. Cytochromes and ATPase were present in the membrane from cells grown in normal broth, but were deficient in the cells grown in glucose containing media. Polypeptide analysis of the membrane proteins showed a deficiency of the bands corresponding to these enzymes. They were not induced by the additionof oxygen to cells grown in glucose containing media. It was concluded that glucose was the dominant factor inhibiting the formation of these membrane enzymes.

Efficiency of bacterial filtration in various commercial air filters for hospital air conditioning

Filtration efficiency of high-efficiency particulate air (HEPA) filters is said to be over 99.97% of removal rate against the mist of thermogenerating-type of dioctyl phthalate with average particles diameter of 0.3 micrometer, as tested by the U.S. Military Standard 282 (1956). Filtration of bacterial aerosols through commercial air filters was tested to examine the efficiency of bacterial filtration with eight kinds of air filters. Percentage of bacterial filtration efficiency (% BFE) of three kinds of HEPA filters showed 100% BFE, while NBS-95 and NBS-85 showed over 99% BFE. BFE of NBS-75 air filter was 91.75%.

Structural analysis of the cellular constituents of a fresh clinical isolate of Staphylococcus aureus, and their role in the interaction between the organisms and polymorphonuclear leukocytes in the presence of serum factors

The in vitro interaction of a fresh clinical isolate of Staphylococcus aureus and polymorphonuclear leukocytes was investigated. The importance of the various cellular constituents as host immunological factors was analyzed, and the results suggested that two components, namely, an acidic polysaccharide consisting of a predominance of aminogalacturonic acid and a strain-specific mucopeptide complex, may be involved in impeding in vitro opsonization of the organism by leukocytes. Immunochemical analysis indicated that the acidic polysaccharide possessed the same immunodominant aminogalacturonic acid residues as the antiphagocytic acidic antigen of the encapsulated prototype Scott strain. Antisera derived from rabbits immunized with strain D contained two types of opsonins, those with acidic polymer specificity and those with mucopeptide complex specificity.

Cervicofacial abcesses of unknown origin. A survey of eighty-one cases

A survey of eighty-one patients with cervicofacial abscesses of unknown origin is presented. The salient clinical features and the treatment of the abscesses are described. Mainly affected were children under 4 years of age, and the submandibular and submental regions were the most common sites of involvement. Staphylococcus aureus was the predominant pathogenic organism, and epidemic strains were implicated in some cases. A high incidence of resistance to penicillin was noted. The nasal vestibule is postulated to be reservoir of the organisms, and the possible relationship between infection, malnutrition, and a mild degree of anemia is examined.

The bactericidal potential of various endodontic materials for primary teeth

An in vitro study of the bactericidal or bacteriostatic effects of several pulp therapy compounds and their components on selected bacterial commonly isolated from infected primary teeth was undertaken. It was determined that zinc oxide had no inhibitory effects on E. coli, Staph. aureus, and Strep. viridans; however, the addition of eugenol to this system retarded the growth of only the grampositive organisms. The inclusion of zinc acetate as a setting accelerator inhibited both gram-positive and gram-negative bacteria. Also the inhibitory effects on these three organisms could be greatly enhanced by the addition of formocresol or paraformaldehyde to the zinc oxide--eugenol--zinc acetate system. It was also noted that Sargenti's N-2 paste was apparently no more effective in retarding growth of these organisms than the mixtures. Only the lead tetroxide and hydorcortisone present in the N-2 paste was toxic to the Staph. aureus but not to E. coli or to Strep. viridans. The other heavy metals in N-2 apparently have no antibacterial activity in the manner in which they were tested. This evidence suggests, but is not conclusive, that zinc oxide--eugenol--zinc acetate, with or without formaldehyde-containing compounds, may be effective in the elimination of bacteria from pulpotomized primary teeth. Therefore, the addition of highly cytotoxic chemicals which will remain sealed in a root canal and be active for extended periods of time may not be necessary for successful treatment.

Microcalorimetric study of the effects of cephalexin and cephaloridin on Escherichia coli and Staphylococcus aureus

The kinetics of the antibacterial actions of cephalexin and cephaloridin against a strain of Escherichia coli and a strain of Staphylococcus aureus were studied by a flow microcalorimeter. The heat production was related to the number of viable organisms (CFU ml-1), the pH, the optical density of the culture medium (OD540), and the morphology of the antibiotic-exposed bacteria. No heat effects could be registered when the number of CFU was below 10(4) ml-1. The addition of cephalexin, 2.5 microgram ml-1 (5 x MIC), to cultures of S. aureus caused a decrease in the heat production which was only roughly correlated with the number of CFU ml-1. This was also the case when 9.0 microgram ml-1 (2 x MIC) of this drug were added to cultures of E. coli. Two to three hours after the drugs had been added, no heat effects could be registered for the following 6--8 hours, after which an increase in the heat production again occurred. The MIC and MBC of the organisms isolated during this late heat increase were 8--40 times higher than those of the parent test organisms. A direct relation between drug concentration and response, i.e. heat effects produced, was found when increasing concentrations of cephalexin, i.e. 1.0 up to 50 micrograms ml-1 (2--100 x MIC) were added in the logarithmic growth phase to cultures of S. aureus. In ampoule calorimetric experiments, E. coli was cultured in a non-aerated, sealed growth vessel in the presence of cephalexin or cephaloridin in concentrations corresponding to 1/2 x MIC. The thermograms did not differ in shape, although the heat effects occurred somewhat later in the culture containing cephaloridin.

A study on the microbial filtration efficiency of surgical face masks--with special reference to the non-woven fabric mask

With the experimental apparatus designed and made available by Nicholes, we evaluated the bacterial filtration efficienty (B.F.E.) of the non-woven fabric and cotton cloth masks. The apparatus was supplied by Nicholes (U.S. Military Specification 36954 C mask, surgical, disposable). The study presented here was performed as a round robin test with Nicholes. By using this apparatus, comparison was made as to the B.F.E. of the six different kinds of surgical face mask before and after prolonged use. The result was obtained that the disposable mask made of glass fiber mat combined with non-woven fabric proved to be the highest in performance with a B.F.E. of 98.1-99.4%. It is useful both in preventing hospital infection and in general clinical practice. The B.F.E. of the conventional cotton cloth masks is not only lower but variable over a wide range of 43.1-93.6%.

Surface properties of cells of some methicillin-resistant strains of Staphylococcus aureus

Methicillin-sensitive (MS) cells of Staphylococcus aureus had a minimum electrophoretic mobility at pH 4.5, whereas methicillin-resistant (MR) strains showed only a slight plateau effect. Trypsin removed the trough effect of the MS Oxford strain. There was no correlation between surface lipid and resistance in MR strains. Cell walls of MS strains contained much more teichoic acid than walls of MR strains. Lysostaphin lysed all MR and MS strains, and mucopeptide does not appear to be involved in resistance to methicillin.

Formation of regular packets of Staphylococcus aureus cells

Staphylococcus aureus, which usually forms grape-like clusters, has the ability to form regularly arranged cell packets. These regular cell packets are formed when the activity of its separation enzyme(s) is lost either by treatment with detergents, such as sodium dodecyl sulfate or Trition X-100, or by mutation of the cells. These cell packets consisted of 8 to 64 spherical cells that have a three-dimensional arrangement. Some irregularity in the arragement of cells in packets, however, can be observed by scanning electron microscopy. It is concluded that S. aureus fundametally divides along three definitely oriented planes that are located at right angles to each other. After cell division, the cells usually become translocated due to the action of a separation enzyme(s) to form grape-like clusters.

Induction of adjuvant arthritis in the rat by various bacterial cell walls and their water-soluble components

A number of purified cell walls of various gram-positive bacteria had arthritogenic activity in the rat. The water-soluble adjuvant-active component(s), which were isolated from some of these cell walls by utilizing a peptidoglycan-degrading enzyme, did produce severe adjuvant arthritis. However, the components obtained by digestion with glycan-degrading enzymes failed to produce arthritis. Thus, the present finding indicates the importance of a peptidoglycan portion, especially its intact glycan chain, for induction of adjuvant arthritis.

[Capsule formation in Staphylococcus aureus as a reason for nontypability by phages (author's transl)]

In Staph. aureus strains isolated from human pathological material the frequency of strains which did not react with typing phages (NT-strains) was found to be about 30%. In one half of the NT strains the reaction with typing phages is prevented by a capsule. The capacity for capsule-formation is lost after propagation of the cells in a liquid glycerol-minimal-medium; thus the cells become typable by phages. The capacity for capsule-formation can be restored after intraperitoneal injection into mice. A new propagation in glycerol-minimal-medium leads again to a loss of the capsule.

[Interaction of acridine orange with teichoic acids of Staphylococcus aureus]

Teichoic acids of the cell wall of Staphylococcus aureus 209-P belong to the class of ribitol teichoic acids and can bind actively the molecules or acridine orange, changing its optical properties. The intravital fluorochromy of the cells with acridine orange may be caused by the sorption of its molecules by the teichoic acids of the cell wall.