TEMPORAL VARIATION IN GENETIC DIVERSITY AND STRUCTURE OF A LOTIC POPULATION OF BURKHOLDERIA (PSEUDOMONAS) CEPACIA

The genetic structure and temporal patterns of genetic diversity in a population of Burkholderia (Pseudomonas) cepacia, isolated from a sout heastern blackwater stream, were investigated by multilocus enzyme ele ctrophoresis. Allelic variation in seven structural gene loci was moni tored at a single stream location at 0, 6, 12, and 21 h and at 2, 4, 8 , 16, and 32 days, Over the length of the study, 217 isolates were col lected, from which 65 unique electrophoretic types (ETs) were identifi ed. Most of these ETs were present at only one or two time periods and were considered transients; however, one resident ET was particularly abundant (64 of the 217 isolates [29.4%]) and was found at all time p oints except day 32. The mean genetic diversity of the entire populati on was 0.520, and the index of association (a measure of multilocus li nkage disequilibrium) was 1.33, These results, taken in conjunction wi th a previous study focusing on spatial patterns of genetic diversity in lotic B. cepacia, show that these bacterial populations exhibit gre ater variability among sites than within a site over time, suggesting relative stability over short time periods.