In order to determine whether hand carriage of aerobic Gram-negative rods is continuous we used the glove-handwash technique to sample the hands of two groups (four each) of health care workers with normal hands (surgical intensive care unit, medical ward) and one group (four) with hand dermatitis (HD) and a group (five) of control subjects -- secretaries with no exposure to patients. Each subject was sampled repeatedly over three to six weeks. The mean number of samples for each group was 25.2, 23.2, 19.8 and 25.8 respectively. The HD group had more samples positive for aerobic Gram-negative rods than did the other two groups of health care workers while the control group had more samples positive than any of the three health care groups. Using various typing schemes and the following definition of continuous carriage (the isolation of an organism of the same serotype, pyocin type or biotype from more than two handwash samples) we found that 4 of 11 subjects from whom Klebsiella pneumoniae was isolated carried this organism continuously; 2 of 3 carried Pseudomonas aeruginosa continuously and 4 of 5 of the control subjects carried the same biotype of Enterobacter agglomerans continuously. We conclude that continuous hand carriage of aeroic Gram-negative rods is common and, among health care workers, those with hand dermatitis carry Gram-negative rods more frequently and in greater numbers than health care workers without hand dermatitis.

SUMMARYA quantitative culture technique (hand washed in a glove containing broth for 30 s) was used to determine the frequency ofhand carriage ofaerobic Gram-negative rods by various groups of health care workers and 104 control subjects. Overall, 31 % of health care workers carried aerobic Gram-negative rods on their hands compared to 59 % of control subjects (P < 0-001). Enterobacter agglomerans accounted for 40 % of the isolates, and other Enterobacter spp. 7 %. Other organisms included Acinetobacter calcoaceticus 21 %, Serratia spp. 11 %, Klebsiella spp. 10 %, Moraxella spp. 3 %, Pseudomonas spp. 3 %, Proteus spp. 1V5 %, Escherichia coli 1 %; Morganella morganii, Citrobacter freundii, Aeromonas sp. and an isolate that was not speciated accounted for 0 5 % each. We conclude that endemic hand carriage ofaerobic Gram-negative rods by health care personnel is common, but significantly less than that of control subjects. Enterobacter agglomerans is found so frequently on the hands of control subjects that it must be considered part of the normal hand flora.