Relationship between the Viable but Nonculturable State and Antibiotic Persister Cells

Abstract

Bacteria have evolved numerous means of survival in adverse environments with dormancy, as represented by "persistence" and the "viable but nonculturable" (VBNC) state, now recognized to be common modes for such survival. VBNC cells have been defined as cells which, induced by some stress, become nonculturable on media that would normally support their growth but which can be demonstrated by various methods to be alive and capable of returning to a metabolically active and culturable state. Persister cells have been described as a population of cells which, while not being antibiotic resistant, are antibiotic tolerant. This drug-tolerant phenotype is thought to be a result of stress-induced and stochastic physiological changes as opposed to mutational events leading to true resistance. In this review, we describe these two dormancy strategies, characterize the molecular underpinnings of each state, and highlight the similarities and differences between them. We believe these survival modes represent a continuum between actively growing and dead cells, with VBNC cells being in a deeper state of dormancy than persister cells.

Transformation of Helicobacter pylori into Coccoid Forms as a Challenge for Research Determining Activity of Antimicrobial Substances

“…In the first case by the lack of staining of such cells with propidium iodide [78], in the second case by the possibility to resuscitate them in culture media [79]. It is suggested that a very thin sectioning during TEM preparation may contribute to the apparent lack of small, highly condensed nucleoid and protein aggregates, giving the effect of empty cytosol (ghost cells) ( Figure 6) [80]. Formation of these structures is promoted by the reduction in iATP and is crucial for the survival of microorganisms under stressogenic conditions [81].…”

“…For this purpose, SYTO9/propidium iodide (so called Live/Dead) and NPN staining are most commonly used in H. pylori studies [69]. It seems that a basic criterion for cells with the VBNC phenotype, an integrity of cellular structures, contributes to an effective determination of the viability of coccoid H. pylori forms using the aforementioned methods [80]. It should be borne in mind, however, that morphological transition may somehow affect the adsorption or retention capacity of some fluorescent dyes.…”

Unusual deprivation of compatible solutes in Acinetobacter baumannii

“…As virulence can be retained in the VBNC state, or regained upon resuscitation, it is essential to know whether a certain pathogen can persist in a VBNC state to develop reliable detection methods (Li et al ., ). Additionally, decontamination and treatment can be hindered, as dormant cells are often more resistant against antibiotics and harsh conditions in general (Oliver, ; Li et al ., ; Ayrapetyan et al ., ). In the case of A .…”

“…As virulence can be retained in the VBNC state, or regained upon resuscitation, it is essential to know whether a certain pathogen can persist in a VBNC state to develop reliable detection methods . Additionally, decontamination and treatment can be hindered, as dormant cells are often more resistant against antibiotics and harsh conditions in general (Oliver, 2010;Li et al, 2014;Ayrapetyan et al, 2018). In the case of A. baumannii, bacteria could undergo a switch to the VBNC state, for example in body fluids with elevated osmolarity, which would increase their persistence upon release to the hospital environment.…”

Retos actuales en la detección e identificación de Listeria monocytogenes

“…El estado VBNC describe una subpoblación de bacterias que han perdido transitoriamente su capacidad de crecer en los medios de cultivo de rutina en los que anteriormente podían crecer. Estas bacterias exhiben una actividad metabólica significativamente menor, aunque presente, que las bacterias en crecimiento activo, continúan manteniendo la integridad de su membrana y realizan la síntesis de proteínas (19) .…”