Pulmonary clearance of Staphylococcus aureus in mutant mice with some hereditary alterations resembling cystic fibrosis.

Pulmonary clearance for Staphylococcus aureus has been examined in two inbred strains 
of mice with some hereditary alterations resembling cystic fibrosis (CF). These 
mice were mice with abnormal electrolyte metabolism (DBA/@J-cri), mice with spontaneous 
pneumonitis (C57BL/6J-bg), and mice without any CF-like alterations (BALB/c). The methods 
used to produce pulmonary infection were essentially those of Laurenzi and 
associates adapted as needed for mutant mice. The animals mentioned above 
were exposed to a finely divided aerosol suspension of a coagulase-positive 
strain of S. aureus in phosphate buffer. Immediately after the exposure, 
half of the animals were killed, and the remaining half were 
killed 4 hr later. In each experimental unit the mice killed 
immediately after the exposure were as similar as possible to the 
mice killed 4 hr later with respect to genotype, age, and 
sex; some were siblings. The uncleared bacteria (UBR) in 4 hr 
were 0.20 for the mice without any CF-like alterations (BALB/c) and 
the C57BL/6J-bg, bg/bg genotypes; 0.28 for C57BL/6J-bg, +/? genotypes; 0.50 for 
the DBA/2J-cri, +/? genotypes; and 0.56 for cri/cri mice. The number 
of viable staphylococci found immediately after the aerosol exposure (Co) in 
the C57BL/6J-bg strain is significantly lower than the Co of the 
BALB/c (P < 0.05) and DBA/2J-cri strain (P < 0.01). The 
latter two did not differ from each other. There was no 
sex difference with respect to the UBR and Co data. The 
DBA/2J-cri strain of mice, where the cri mutation first appeared, has 
a decreased capacity for clearance of S. aureus by the lung. 
Together with the other CF-like alterations of the cri mutation, namely 
failure for the reabsorption of Na+ by the parotid duct, high 
level of Na+ in the fur, and CF abnormal serum factor 
activity in the serum of the cri/cri mice, we suggest that 
the cribriform degeneration mouse mutant may provide a potential animal model 
for studying CF. The finding of a mouse mutation with electrolyte 
alterations and CF-like abnormal serum activity, simialr to the activity found 
in CF children, in an inbred strain of mice with a 
decreased bacterial clearance by the lungs, makes these mice very useful 
for CF studies. 