Microbiological examination of the contents of vacuum cleaner bags collected from case and control homes demonstrated a statistically significant association (OR = 3.13, CL = 1.32-7.50) between infant salmonellosis cases and Salmonella contamination of the vacuums used in their homes. This suggests that some cases of infant salmonellosis may result from contact with contamination in the home environment and that steps taken to protect infants from potentially contaminated dust or dust aerosols may reduce the risk of contracting this infection.

In 1985 the vernacular name Enteric Group 90 was coined for a small group of strains that had been referred to our laboratory as probable strains of Salmonella but did not agglutinate in Salmonella typing antisera. By DNA-DNA hybridization (hydroxyapatite method, 32p), seven strains of Enteric Group 90 were found to be closely related (98 to 100% at 60°C and 94 to 100% at 75°C) to the first strain received (0370-85). The relatedness of Enteric Group 90 to 62 strains of other species of the family Enterobacteriaceae was only 6 to 41%, with the highest values obtained with strains of SalmoneUla, Kluyvera, ShigeUa, Klebsie1la, Enterobacter, and Citrobacter. We propose a new genus, Trabulsiella, with a single new species, Trabulsiella guamensis, for the highly related group of eight strains formerly known as Enteric Group 90. The type strain is designated ATCC 49490 (CDC 0370-85). T. guamensis strains grew well at 36°C and had positive reactions in the following tests: methyl red, citrate utilization (Simmons) (38% positive at day 1, 88% positive at 2 days), H2S production, lysine decarboxylase, arginine dihydrolase (50% positive at 2 days, 100% positive at 7 days), ornithine decarboxylase, motility, growth in KCN medium, mucate fermentation, acetate utilization, nitrate reduction to nitrite, weak tyrosine hydrolysis (88% positive at 2 days, 100% positive at 7 days), and ONPG (o-nitrophenyl-P-D-galactopyranoside) test. The strains fermented D-glucose with gas production and fermented L-arabinose, cellobiose, D-galactose, D-galacturonate, maltose, D-mannitol, D-mannose, L-rhamnose, D-sorbitol, trehalose, and D-xylose. T. guamensis strains had negative reactions in the following tests: indole production (13% positive), Voges-Proskauer, urea hydrolysis, phenylalanine deaminase, malonate utilization, lipase (corn oil), DNase, oxidase, pigment production, and acid production from adonitol, D-arabitol, dulcitol, erythritol, myo-inositol, melibiose, a-methyl-D-glucoside, raffinose, and sucrose. There were delayed positive reactions for gelatin liquefaction (22°C), which was positive at 12 to 23 days, esculin hydrolysis (13% positive at day 1, 50% positive at 7 days), lactose fermentation (13% positive at 3 to 7 days, 100% positive at 8 to 10 days), glycerol fermentation (88% positive at 7 days), and salicin fermentation (13% positive at day 1, 88% positive at 7 days). All strains were susceptible by the disk diffusion method to colistin, nalidixic acid, gentamicin, streptomycin, kanamycin, chloramphenicol, and trimethoprim-sulfamethoxazole, and most strains were susceptible to sulfadiazine (75% susceptible), tetracycline (88%), and carbenicillin (75%). The strains were resistant to penicillin, cephalothin, and ampicillin. The strains were isolated from vacuum cleaner dust (five strains), soil (one strain), and human feces (two strains). Although T. guamensis can occur in human diarrheal stools, there is no evidence that it actually causes diarrhea. Its main interest to clinical microbiologists may be its possible misidentif...

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A period of high incidence of human Salmonella infections on the island of Guam saw the emergence of S. waycross as the most commonly isolated serotype as well as a concurrent decreasing proportion of isolates due to S. typhimurium. Predation of local rodents by an introduced snake is believed to account for the decreased prevalence of S. typhimurium infections, but reasons for the increased prevalence of S. waycross infections are unknown.