1. The susceptibility of rabbits to inhalations of pneumococci varies in direct proportion to the virulence of the organism for rabbits. 2. When rabbits are exposed to a pneumococcus spray, irrespective of the virulence of the organism, the bacteria readily penetrate into the lower respiratory tract. 3. When rabbits are exposed to a spray of avirulent degenerated "R" form of pneumococcus, septi...

We demonstrated that during colonization with Streptococcus pneumoniae the nasal mucosal tissues of mice support two populations of pneumococci. Transparent-phase pneumococci can be readily washed from the outer surface, while a second population composed of primarily opaque-phase pneumococci is released only by homogenization of the nasal tissue. The fact that the opaque phase has previously b...

Pneumococcal types which exhibited varying degrees of interaction with the complement system in vitro wee aerosolized into normal and decomplemented rats, and the rate of killing of pneumococci was monitored by serial cultures of whole lung homogenates. The clearance of pneumococci from the alveoli did not correlate with the ability of the pneumococci to be opsonized by complement in vitro. Sim...

In a survey of about forty rough methemoglobin-producing colonies in sputum cultures from a series of individuals suffering from respiratory infections, twelve bile-soluble strains of suspected R pneumococci have been isolated for study. Two of these twelve strains have shown both autolysis in saline solution and serological reactions characteristic of R pneumococci. The findings offer evidence...

The activities of ertapenem (MK-0826) and eight other agents against a range of penicillin-susceptible and -resistant pneumococci were tested by determination of MICs by the microdilution method and by the time-kill methodology. For 125 penicillin-susceptible, 74 penicillin-intermediate, and 86 penicillin-resistant pneumococci, the MICs at which 50% of isolates are inhibited (MIC(50)s) and MIC(...

1. Ethylhydrocuprein hydrochloride in very high dilution inhibits the growth of, and in 18 hours kills, representatives of all four groups of pneumococci in vitro. The killing effect is generally seen in somewhat lower dilutions than the inhibiting effect. No constant or considerable difference is seen in these actions on representatives of the four groups of the pneumococci. The action of ethy...

Complement-containing immune complexes can be presented to phagocytes by human erythrocytes bearing complement receptor 1 (CR1). Although this has long been assumed to be a mechanism by which humans are able to protect themselves from "extracellular" bacteria such as pneumococci, there is little direct evidence. In these studies we have investigated this question by comparing results for erythr...

Certain interesting facts have been obtained regarding the action of normal swine serum, but in the light of present knowledge it is not easy to interpret them. It has been found that the normal serum possesses the property of protecting mice from infection with virulent pneumococci, and of agglutinating virulent S pneumococi and also avirulent R pneumococci. The protective action of the serum ...

1. It has been shown that the whole uncoagulated blood of immune animals is not as highly pneumococcidal in vitro, as has been claimed by others. 2. Cultures of pneumococci in the fresh whole blood of immune animals, as compared with cultures in the blood of susceptible animals, show a greatly prolonged latent period, and, in a general way, the relative lengths of the latent periods of the cult...