Labile type-specific antigen of Moraxella catarrhalis.

By using hot acid extract and double-diffusion studies, an antigen isolated from clinical strains of Moraxella catarrhalis, designated the C antigen, was studied. The antigen is labile, relatively trypsin insensitive, and either polysaccharide or glycoconjugate in nature. At least two serologically distinct C antigens have been identified.

Occurrence of multiple-antibiotic-resistant enteric bacteria in domestic sewage and oxidation lagoons.

The coliform bacterial population in the Grand Forks, N.Dak. sewage system was examined for multiple-antibiotic-resistant organisms over a 1-year period. Multiple-antibiotic-resistant coliforms were found to be common in the sewage, and their numbers remained fairly constant relative to the total coliform population throughout the year. Resistance to kanamycin, tetracycline, and ampicillin was found to be transferable at variable rates. Transfer rates were found to be temperature sensitive and were optimal at 35 degrees C. Although 75% of the multiple-antibiotic-resistant coliforms were capable of transferring resistance at some level, only 25% were capable of transferring resistance at rates greater than 10(-3) transconjugants per initial donor.

A continuing education program for rural communities: evaluating cognitive and behavioral change.

A total of 133 laboratory workers from 60 institutions participated in a unique continuing education project in North Dakota. Cognitive and behavioral changes of the participants were measured in an attempt to evaluate the effectiveness of the Laboratory Education for North Dakota (LEND) program, which included self-instructional programs (SIPs), telelectures, and workshops. The effects of variables such as institutional size, educational level of participants, topic presented, and type of participation were studied. Institutional size had no significant effect on cognitive change (P greater than .05) but had some effect on behavioral change. Educational level was found to significantly affect pretest scores (P less than .05), but was not a major factor in post-test scores. Certain topics presented (i.e., quality assurance and microbiology) resulted in significantly more behavioral changes than other categories. Behavioral changes and degree of cognitive change did not always correspond. Significant correlation was shown between attendance at wet workshops and the number of behavioral changes.

Biotin production and utilization in a sewage treatment lagoon.

Biotin, in a sewage oxidation lagoon also receiving potato processing wastes, was observed to increase two logs during the summer period of waste stabilization and then to decline to near earlier concentrations. Three organisms, Aerobacter aerogenes, Chlorella vulgaris, and Thiocapsa floridana, were at least partially responsible for these fluctuations; the latter two organisms were associated with biotin utilization and the former with biotin production. Since copious quantities of biotin are produced in these waste treatment facilities, the vitamin may act as a useful indicator of microbial action on certain organic molecules, especially in domestic and industrial wastes such as those from municipalities and potato and sugar beet processing plants. Furthermore, the presence of biotin in rivers and streams may be indicative of the discharge of incompletely stabilized wastes from these sources.

Occurrence of purple sulfur bacteria in a sewage treatment lagoon.

The ecology of purple sulfur bacteria in a sewage oxidation lagoon was investigated. Chemical changes in the lagoon were investigated by monitoring biochemical oxygen demand (BOD(5)), sulfide, sulfate, phosphate, total carbohydrates, volatile acids, alkalinity, and pH. Lagoon water temperatures were observed daily. Microbial ecological relationships were deduced by enumerating coliforms, total bacteria other than anaerobes [Tryptone Glucose Extract (TGE) agar], methane formers such as Methanobacterium formicicum, sulfate reducers, purple sulfur bacteria, and algae. Finally, two strains of purple sulfur bacteria were characterized. Two populations, purple sulfur bacteria and total bacteria (TGE agar), reached maximal concentrations in the warmest part of the 1967 summer. Purple sulfur bacteria reached maximal numbers as concentrations of sulfide and volatile acids were depleted, whereas carbohydrates and alkalinity remained unchanged. Low sulfate levels, which were not limiting for sulfate reducers, may be attributable to storage of sulfur within purple sulfur bacteria. No biological, chemical, or physical agent was linked to the removal of coliforms. The increase of algae in the late summer of 1967 may have been related to the low organic content of the lagoon during this period. Although lagoon pH (7.7 to 8.2) was favorable for purple sulfur bacterial growth, temperatures and sulfides were not optimal in the lagoon for these organisms. Chromatium vinosum and Thiocapsa floridana (the predominant lagoon purple sulfur organism in 1967 and 1968) utilized certain carbohydrates, amino acids, volatile acids, and Krebs cycle intermediates. Also purple sulfur bacteria lowered BOD levels as demonstrated by the growth of T. floridana in sterilized sewage.

Clostridium botulinum type F: seasonal inhibition by bacillus licheniformis.

Clostridium botulinum type F has been identified during the summer months in mud samples from a small stream. Its absence during the period from October to April in these mud samples is attributed to the presence of Bacillus