Pneumococcal pulmonary infection, septicaemia and survival in young zinc-depleted mice.
The aim of the present study was to explore whether mice fed a diet low in Zn (2.0 mg Zn/kg diet) for a relatively short period of time were more prone to severe Streptococcus pneumoniae infection than mice fed a normal diet (25 mg elemental Zn/kg). The Zn-deficient mice were compared with mice in two Zn-adequate control groups; one pair-fed and another with free access to the diet. After 2 weeks feeding, the mice were infected intranasally under anaesthesia with a suspension containing about 10(7) pneumococci. Clinical status was observed every day and blood samples were examined for S. pneumoniae every second day for a week. All infected mice examined carried the infecting strain intranasally. The survival time and time before positive blood culture were significantly shorter in the Zn-depleted group than in the pair-fed Zn-adequate group (hazard ratios 15.6 and 3.2, and respectively). At the end of the observation period, ten of the twelve mice in the Zn-deficient group were dead while one of twelve and two of twelve were dead in the two Zn-adequate control groups. This study shows that even acutely-induced Zn deficiency dramatically increases the risk of serious pneumococcal infection in mice.
Strand
T A
TA
Centre for International Health and Department of Microbiology and Immunology, The Gade Institute, University of Bergen, Norway N-5021. Tor.Strand@cih.uib.no
Briles
D E
DE
Gjessing
H K
HK
Maage
A
A
Bhan
M K
MK
Sommerfelt
H
H
D000818:Animals; D016470:Bacteremia / Q000209:etiology* / Q000378:metabolism; D001835:Body Weight; D004198:Disease Susceptibility; D005260:Female; D005269:Femur / Q000737:chemistry; D051379:Mice; D008807:Mice, Inbred BALB C; D018977:Micronutrients / Q000008:administration & dosage / Q000032:analysis / Q000172:deficiency*; D011018:Pneumonia, Pneumococcal / Q000209:etiology* / Q000378:metabolism / Q000401:mortality; D016016:Proportional Hazards Models; D015032:Zinc / Q000008:administration & dosage / Q000032:analysis / Q000172:deficiency*
D018977:Micronutrients; D015032:Zinc