Lack of Stage-Specific Proteins in Coccoid Helicobacter pylori Cells

Abstract

Helicobacter pylori exists in two distinct forms, rod shaped or coccoid, in stomachs of infected patients. Based on in vitro proteome comparisons, there are no detectable coccoid-specific proteins, which argues against the specific adaptation of coccoid Helicobacter to distinct biological functions, such as enhanced persistence or transmission to other hosts

The Stringent Response Is Required for Helicobacter pylori Survival of Stationary Phase, Exposure to Acid, and Aerobic Shock

“…The biological significance of the coccoid state has been greatly debated. Some have proposed that it represents a dormant, spore-like stage and is possibly the transmissible form of the organism (24), although analysis of the proteome content argues against this model (8). Our observation that more of the ⌬spoT mutant cells appeared coccoid at 24 and 48 h than the wild-type population is consistent with a role for spoT in protection against stationary-phase stresses, but it cannot in itself account for the dramatic difference in viability between these populations at 50 h. The fact that H. pylori precociously adopts the coccoid form in the absence of spoT argues against the coccoid morphology being part of a developmental program of stress resistance that is regulated by the stringent response, as in Bacillus subtilis (26).…”

Failure To Detect Helicobacter pylori DNA in Drinking and Environmental Water in Dhaka, Bangladesh, Using Highly Sensitive Real-Time PCR Assays

“…Under suboptimal conditions, H. pylori transforms into nonculturable spherical or coccoid forms. To date, it is not clear if this process is reversible or if the coccoid form is infectious or even viable, but it has been reported to retain some metabolic activity, its genome, and an intact membrane (1,6,12,28,38,47).Transmission of H. pylori has been proposed to occur via gastric-oral, oral-oral, or fecal-oral routes, with studies suggesting transmission through saliva and dental plaque (14, 23), normal and diarrheal stools (18,23,41,43), and vomitus (30, 41). Infected mothers or older siblings, low standards of living, and crowded households have been shown to be major risk factors for contracting H. pylori (25,35,50).…”

“…Under suboptimal conditions, H. pylori transforms into nonculturable spherical or coccoid forms. To date, it is not clear if this process is reversible or if the coccoid form is infectious or even viable, but it has been reported to retain some metabolic activity, its genome, and an intact membrane (1,6,12,28,38,47).…”

Coccoid Form of Helicobacter pylori as a Morphological Manifestation of Cell Adaptation to the Environment

“…Similarly, the gastrointestinal pathogen Helicobacter pylori is known to mainly present a spiral shape in the natural habitat within the human host, but it converts into a coccoid shape when exposed to detrimental environmental circumstances (2). In this case, however, the pleiomorphic nature of the bacterium has been the subject of intensive debate over the last 10 years, with part of the scientific community still maintaining that the coccoid shape represents a degraded, nonviable form of the cell (8,13,19,25). There are several factors contributing to this situation.…”