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Legionellosis is an infection acquired through inhalation of aerosolized water droplets containing Legionella bacteria. In August 2018, public health officials in New Hampshire launched an investigation into a legionellosis outbreak. They identified 49 illnesses likely associated with the outbreak and implicated an improperly maintained hot tub at a hotel. The same strain of Legionella pneumophila serogroup 1 was found in both the hot tub and in samples from two patients with Legionnaires' disease. The indoor hot tub vented to the outdoors, which is how some patients with confirmed legionellosis likely acquired the infection despite not entering the hotel during the incubation period. This outbreak is notable for 1) likely illness acquisition through the exterior vent of the hot tub room and 2) use of whole genome sequencing to link environmental and patient specimens. Collaboration among public health and environmental officials, laboratorians, and building managers was essential to determining the source of the outbreak and preventing further illness., Introduction Legionella bacteria are aerobic, Gram-negative, intracellular pathogens commonly found in fresh water and soil (Mercante & Winchell, 2015). Human infection typically is acquired through inhalation of Legionella-containing aerosols. Most [...]

Zegionella spp. are ubiquitous in nature, live in soil and water, and frequently inhabit human-made water distribution systems, hot water tanks, decorative fountains, and cooling towers (1,2). Persons with underlying [...]

Two-component regulatory systems play a major role in the physiological response of bacteria to environmental stimuli. Such systems are composed of a sensor histidine kinase and a response regulator whose ultimate function is to affect the expression of target genes. Response regulator mutants of Campylobacter jejuni strain F38011 were screened for sensitivity to sodium deoxycholate. A mutation in Cj0643, which encodes a response regulator with no obvious cognate histidine kinase, resulted in an absence of growth on plates containing a subinhibitory concentration of sodium deoxcholate (1%, wt/vol). In broth cultures containing 0.05% (wt/vol) sodium deoxycholate, growth of the mutant was significantly inhibited compared to growth of the C. jejuni F38011 wild-type strain. Complementation of the C.jejuni cbrR mutant in trans restored growth in both broth and plate cultures supplemented with sodium deoxycholate. Based on the phenotype displayed by its mutation, we designated the gene corresponding to Cj0643 as cbrR (Campylobacter bile resistance regulator). While the MICs of a variety of bile salts and other detergents for the C. jejuni cbrR mutant were lower, no difference was noted in its sensitivity to antibiotics or osmolarity. Finally, chicken colonization studies demonstrated that the C. jejuni cbrR mutant had a reduced ability to colonize compared to the wild-type strain. These data support previous findings that bile resistance contributes to colonization of chickens and establish that the response regulator, CbrR, modulates resistance to bile salts in C. jejuni.

Analysis of the entire bont/F nucleotide sequences from 33 type F botulinum toxin-producing clostridial strains isolated from environmental sources and botulism outbreak study is reported. The results demonstrated the extensive nucleotide diversity present among genes encoding type F neurotoxins from strains with different phylogenetic backgrounds and from various geographical sources.

The entire bont/A- and bont/B-associated neurotoxin gene clusters of Clostridium botulinum type Ab strain CDC41370 and the bont/A gene of strain CDC588 was sequenced to understand the neurotoxin gene diversity among C. botulinum type Ab strains. The differences observed in the toxin gene cluster compositions and bont/A and bont/B nucleotide sequences indicated that they might have evolved from separate recombination events.

Studied were conducted on a group of five clonally related Clostridium botulinum type A strains isolated from different sources. The strains are observed to contain a variant bont/A1 with five nucleotide polymorphisms compared to the gene in C. botulinum strain ATCC 3502 and also had a common toxin gene cluster composition (ha-/orfX+).

The genotype and phenotypic attributes of Campylobacter jejuni poultry isolates are examined. The abilities to invade INT 407 cells and levels of secretion of virulence proteins are found to be different in both isolates.