title: In vivo pH of induced soft-tissue abscesses in diabetic and nondiabetic mice.
abstract: Infections in the diabetic host have been shown to persist longer than those in the nondiabetic host. To investigate whether intra-abscess milieu might be a contributing factor to this persistence, the in vivo intra-abscess pH was measured in induced soft-tissue abscesses in diabetic and nondiabetic mice. Two models (female genetically obese insulin-resistant and male streptozocin-induced diabetic mice) were used with appropriate controls. The bacteria injected to produce the soft-tissue abscesses were Bacteroides fragilis and Enterococcus (B + E), Staphylococcus epidermidis and Enterococcus (S + E), and S. aureus (SA). Intra-abscess pH measured on day 3 was consistently and significantly lower in all diabetic mice compared with their controls. In the diabetic mice, the pH of an abscess induced with B + E, S + E, and SA was 6.28 (n = 17), 6.79 (n = 10), and 6.52 (n = 10), respectively; the pH in the controls was 7.21 (n = 20), 7.30 (n = 10), and 7.17 (n = 10), respectively. Differences in all groups between diabetic and nondiabetic mice were significant. The blood glucose values of the diabetic mice averaged 722 mg/dl, and in the nondiabetic mice were 210 mg/dl. No animals were ketotic. There were no significant differences in total colony counts between any groups. In conclusion, there is a significantly lower pH in the abscess of the diabetic host compared with the nondiabetic host that is not related to the numbers or types of causative bacteria.
authors.affiliation: Department of Medicine, University of Southern California, Rancho Los Amigos Medical Center, Downey 90242.
authors.forename: A N
authors.initials: AN
authors.lastname: Bessman
authors.forename: J
authors.initials: J
authors.lastname: Page
authors.forename: L J
authors.initials: LJ
authors.lastname: Thomas
mesh_terms: D000038:Abscess / Q000378:metabolism* / Q000382:microbiology; D000818:Animals; D001442:Bacteroides Infections / Q000378:metabolism; D001441:Bacteroides fragilis; D003921:Diabetes Mellitus, Experimental / Q000150:complications* / Q000276:immunology; D006863:Hydrogen-Ion Concentration; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D013203:Staphylococcal Infections / Q000378:metabolism; D013212:Staphylococcus epidermidis; D013291:Streptococcus / Q000378:metabolism