Characterization of the coliform and enteric bacilli in the environment of calves with colibacillosis.

In the first part of the present study the coliform and enteric bacilli in the environment of calves with colibacillosis were examined. The occurrence, number, and pathogenic properties of Escherichia coli in barnyard soils were obtained from six cattle ranches. The O and K serogroups of E. coli isolates obtained from the feces of calves with colibacillosis born at these cattle ranches were determined, and their serotypes were compared with the E. coli O and K serotypes found in soils. The results showed a reservoir of potentially pathogenic E. coli in barnyard soils contaminated with bovine feces. For the second part of this study, 6 healthy calves and 51 calves with colibacillosis were studied. The numbers of total aerobic heterotrophic bacteria, total streptococci, fecal streptococci, total coliforms, and fecal coliforms in the feces of calves were determined. In addition, coliform and enteric bacilli from the feces of both healthy and diseased calves were identified, and their indole, methyl red, Voges-Proskauer, citrate (IMViC) types were described. In parallel, the IMViC types of coliform and enteric bacilli isolated from barnyard soils previously contaminated with bovine feces were compared with those isolated from uncontaminated soils. All fecal specimens were also examined for the presence of rotavirus. No significant effect on the numbers of the bacterial types was found. The results suggest that the predominant IMViC types found in the feces of calves with colibacillosis originate from the soil. From this study it is apparent that the occurrence, number, and survival of E. coli in barnyard soils is related to ranch husbandry and sanitary practices.

Inclusion bodies in Plesiomonas shigelloides.

Inclusion bodies were discovered in seven environmental isolates of Plesiomonas shigelloides and the P. shigelloides control (ATCC 14029). Differential staining indicated that the inclusion bodies may be composed of polyphosphates, and developmental stages of the bodies may occur. The inclusion bodies may be useful for rapid presumptive identification of this organism.

Bacterial Symbionts in the Sugar Beet Root Maggot, Tetanops myopaeformis (von Röder).

Aerobic heterotrophic and facultative anaerobic bacteria were isolated from all developmental stages of the sugar beet root maggot, Tetanops myopaeformis (von Röder). Two distinct bacterial symbiotic relationships were observed. Serratia liquefaciens and Serratia marcescens were found to be associated with all developmental stages. Bacterial symbiont transmission occurred from one generation to the next. Symbionts were transferred from the male reproductive system to the female reproductive system, where both an internal infiltration of the egg chorion and an external smearing of the eggs occurred during oviposition. Pseudomonas maltophilia was found in association with the larval gut and the inner surface of the puparium. Electron microscopy of the inner puparial surface revealed symbionts within the chitinous wall. In vitro symbiont chitinase production was found, using both nephelometric (turbidimetric) and N-acetylglucosamine assays. A relationship appeared to exist between adult fly emergence and enzymatic chitin degradation of the puparium by the bacterial symbionts.

Effect of oxytetracycline as a turkey feed additive.

Turkeys were given oxytetracycline (OTC) as a feed supplement at levels of 0 g, 50 g, and 200 g OTC per ton of feed. After 8, 16, and 18 weeks the birds were sacrificed and bacteria were isolated from heart blood and liver tissue. When these isolates were tested for resistance against eight antibiotics, a direct correlation was observed between the level of supplement and the level of antibiotic resistance in the bacterial isolates. In postmortem studies on the livers from birds consuming both levels of OTC, an increase in the occurrence of lesions was observed. The livers from control birds appeared to have more granulomas.

Effect of dietary oxytetracycline on microorganisms in turkey feces.

Thirty-six two-day old male turkey poults were divided into three groups and fed three levels of oxytetracycline; 0, 110 or 440 mg. per kg. of ration, respectively, for nine weeks. The poults were given an oral spectinomycin plus vitamin treatment at the hatchery but were not fed before the start of the experiment. Defecated feces from each group were sampled at weekly intervals and analyzed for bacteriological content, especially for members of the Enterobacteriaceae. Total aerobic counts of 3 x 10(8) and total anaerobic counts of 2 x 10(9) were obtained. The majority of the Enterobacteriaceae were Escherichia coli but some Klebsiella sp., the Bethesda-Ballerup group of paracolon bacteria and Arizona sp. were also isolated. Antibiograms of the enteric isolates indicated that an increase in multiple antibiotic resistance occurred when increased amounts of antibiotic were fed.