Culture-positive Animals Research Articles

Acute and Chronic Bacterial Infection in the Rat Urinary Tract: Immunofluorescent Localization of Immunoglobulins

To study the relative concentrations and appearance of immunoglobulin in the bladder and kidneys of rats with acute and chronic urinary tract infections, three groups of female Sprague-Dawley rats were studied. Group I underwent weekly intraurethral inoculation with Escherichia coli 07. Group II received inoculation of 0.2ml of PBS alone. Group III were unmanipulated controls. Bladder and kidney washings were obtained for bacterial colony counts and organism identification. Bladder and kidney tissue was prepared for immunofluorescent examination using goat or rabbit antirat IgA, IgM, or IgG layered with fluorescent-labeled rabbit antigoat or goat antirabbit serum. Negative immunofluorescent controls substituted PBS for antirat serum. No significant difference was noted between bladder and kidney cultures in groups I and II. Comparison of immunofluorescent intensity between groups I and III demonstrated that IgM intensity was greatest between weeks one and three in bladders and kidneys, then decreased to non-significant levels. Bladder IgG intensity peaked at week four and remained elevated throughout the remainder of the study while renal IgG intensity was significant throughout the study period. Renal and bladder IgA was noted only sporadically. Comparison of culture positive animals to culture negative animals (groups II and III) demonstrated a lower immunofluorescent intensity score for culture negative animals. Discrete cellular immunofluorescence was evident in 19.1% of bladders and compared to 0.6% of kidneys. This study suggests that the immunologic response in the rat to intraurethral inoculation and infection is biphasic (IgM followed by IgG) and that a local cellular immunologic response may exist in the bladder.

Establishment of genital tract infection in the CF-1 mouse by intravaginal inoculation of a human oculogenital isolate of Chlamydia trachomatis.

A human oculogenital strain of Chlamydia trachomatis was instilled intravaginally in the outbred CF-1 mouse to establish cervical infection. The mice were neither hormonally nor immunologically manipulated before inoculation. Duration of chlamydial excretion varied from two to ten days. In the culture-positive animals, IgG and IgM antibody titers were elevated in 38% and 17%, respectively. Neither intracytoplasmic inclusions nor elementary bodies of C. trachomatis were detected in genital tissues. Infection was limited primarily to the cervix and only rarely extended into the uterus. Chlamydial infection could only be established during specific periods of the estrus cycle (metestrus-2, diestrus, and proestrus; P less than .001), stages when leukocytes are present in the vaginal smear. Thus, chlamydial infection of the cervix is cycle-dependent in the mouse. In summary, infection of the cervix of the mouse has been established with a human oculogenital strain of C. trachomatis and may be useful as a model of human chlamydial cervicitis.

Mycobacterial infection in goats: Diagnosis and pathogenicity of the organism

Abstract Counterimmunoelectrophoresis of serum samples and intradermal tuberculin testing were compared with cultural results for the diagnosis of mycobacterial infection in a goat herd. Only eight of 47 culture-positive animals were not identified by a combination of the other two methods. Typical isolates resembled Mycobacterium paratuberculosis in cultural characteristics and mycobactin dependence but serologically resembled Mycobacterium avium . One isolate was inoculated into guinea-pigs, mice, chickens and calves and, although the infection in guinea-pigs, mice and chickens resembled that of M. paratuberculosis , it did not cause Johne's-like disease in calves.