Role of catalase and oxyR in the viable but nonculturable state of Vibrio vulnificus

Kong, In‐Soo; Bates, Tonya C.; Hülsmann, Anja; Hassan, Hosni M.; Smith, Ben; Oliver, James D.

doi:10.1016/j.femsec.2004.06.004

Cited by 135 publications

(121 citation statements)

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“…Expression of these capsular genes during in situ incubation or during the VBNC state in V. vulnificus has not been reported. Previous work in our lab has shown that catalase activity in V. vulnificus decreases at low temperatures, and as a consequence, these cells are unable to defend against the hydrogen peroxide present in routine media and become nonculturable (16). However, during resuscitation at 20°C, catalase activity is restored, leading to a renewed culturable state.…”

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confidence: 87%

In Situ and In Vitro Gene Expression by Vibrio vulnificus during Entry into, Persistence within, and Resuscitation from the Viable but Nonculturable State

Smith

Oliver

2006

Appl Environ Microbiol

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102

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Isolation of Vibrio vulnificus during winter months is difficult due to the entrance of these cells into the viable but nonculturable (VBNC) state. While several studies have investigated in vitro gene expression upon entrance into and persistence within the VBNC state, to our knowledge, no in situ studies have been reported. We incubated clinical and environmental isolates of V. vulnificus in estuarine waters during winter months to monitor the expression of several genes during the VBNC state and compared these to results from in vitro studies. katG (periplasmic catalase) was down-regulated during the VBNC state in vitro and in situ compared to the constitutively expressed gene tufA. Our results indicate that the loss of catalase activity we previously reported is a direct result of katG repression, which likely accounts for the VBNC response of this pathogen. While expression of vvhA (hemolysin) was detectable in environmental strains during in situ incubation, it ceased in all cases by ca. 1 h. These results suggest that the natural role of hemolysin in V. vulnificus may be in osmoprotection and/or the cold shock response. Differences in expression of the capsular genes wza and wzb were observed in the two recently reported genotypes of this species. Expression of rpoS, encoding the stress sigma factor RpoS, was continuous upon entry into the VBNC state during both in situ and in vitro studies. We found the half-life of mRNA to be less than 60 minutes, confirming that mRNA detection in these VBNC cells is a result of de novo RNA synthesis.Vibrio vulnificus is a gram-negative bacterium found in estuarine and coastal waters, including the East, Gulf, and Pacific Coasts of the United States and coastal waters throughout the world (15,26,27,35,46), at high numbers in bivalve mollusks. This bacterium is capable of causing rapidly fatal septicemia and wound infections subsequent to the ingestion of raw or undercooked seafood or following the exposure of wounds to water containing this pathogen (27). The ingestion of raw shellfish, especially oysters, is the most common means of developing primary septicemia, which affects individuals who either are immunocompromised or display underlying hepatic disorders with increased serum iron levels almost exclusively (32). In fact, it has been established experimentally that elevated serum iron levels highly correlate with the growth of V. vulnificus in human serum (25,44,52). V. vulnificus is of extreme significance to the seafood industry, as it causes more seafood-borne deaths than any other organism in the United States and also has the highest case fatality rate of any food-borne infection reported in this country (23). Indeed, 30 to 40 cases resulting in death occur each year in the United States. Interestingly, approximately 90% of all who suffer from V. vulnificus-induced primary septicemia are males, due to the apparent protection from the endotoxin by estrogen in females (24).The environment for V. vulnificus, as for all estuarine bacteria, consists of constantly f...

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confidence: 87%

In Situ and In Vitro Gene Expression by Vibrio vulnificus during Entry into, Persistence within, and Resuscitation from the Viable but Nonculturable State

Smith

Oliver

2006

Appl Environ Microbiol

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102

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“…As we have observed that Vibrio vulnificus cells in the VBNC state show significant culturability when agarose is substituted for agar as a solidifying agent (Kong et al 2004),…”

Section: Lb Agarose Platesmentioning

confidence: 97%

Induction of Escherichia coli and Salmonella typhimurium into the viable but nonculturable state following chlorination of wastewater

Oliver

Dagher

Linden

2005

Journal of Water and Health

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126

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We examined the effects of chlorine disinfection on Escherichia coli and Salmonella typhimurium in secondary-treated wastewater to determine whether such treatment might induce these bacteria into the viable but nonculturable (VBNC) state. In this state, cells lose culturability but retain viability and the potential to revert to the metabolically active and infectious state.To examine the effects of chlorination on cells in different physiological states, cells from the logarithmic and stationary phases, or nutrient starved, or grown in natural wastewater, were studied. Isogenic cells with and without plasmids were also examined. Whereas a mixture of free and combined chlorine, as occurs under typical wastewater disinfection, was found to be rapidly lethal to most cells, regardless of their physiological state or plasmid content, c. 10 4 of the original 10 6 cells ml 21 did survive in the VBNC state. While we were not successful in resuscitating these cells to the culturable state, the presence of such nonculturable cells in treated wastewater offers a potential public health hazard.

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“…KatG is a primary peroxidase, a defense against reactive oxygen species (ROS), and apparently activates the first-line antituberculosis antibiotic isoniazid (28,53). We anticipate that KatG's retention in VBNC cells may be related to anti-ROS activity in stress survival or VBNC induction, as observed in V. vulnificus (54,55).…”

Section: Resultsmentioning

confidence: 99%

A Proteomic Signature of Dormancy in the Actinobacterium Micrococcus luteus

et al. 2017

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Dormancy is a protective state in which diverse bacteria, including Mycobacterium tuberculosis, Staphylococcus aureus, Treponema pallidum (syphilis), and Borrelia burgdorferi (Lyme disease), curtail metabolic activity to survive external stresses, including antibiotics. Evidence suggests dormancy consists of a continuum of interrelated states, including viable but nonculturable (VBNC) and persistence states. VBNC and persistence contribute to antibiotic tolerance, reemergence from latent infections, and even quorum sensing and biofilm formation. Previous studies indicate that the protein mechanisms regulating persistence and VBNC states are not well understood. We have queried the VBNC state of Micrococcus luteus NCTC 2665 (MI-2665) by quantitative proteomics combining gel electrophoresis, high-performance liquid chromatography, and tandem mass spectrometry to elucidate some of these mechanisms. MI-2665 is a nonpathogenic actinobacterium containing a small (2.5-Mb), high-GC-content genome which exhibits a well-defined VBNC state induced by nutrient deprivation. The MI-2665 VBNC state demonstrated a loss of protein diversity accompanied by increased levels of 18 proteins that are conserved across actinobacteria, 14 of which have not been previously identified in VNBC. These proteins implicate an anaplerotic strategy in the transition to VBNC, including changes in the glyoxylate shunt, redox and amino acid metabolism, and ribosomal regulatory processes. Our data suggest that MI-2665 is a viable model for dissecting the protein mechanisms underlying the VBNC stress response and provide the first protein-level signature of this state. We expect that this protein signature will enable future studies deciphering the protein mechanisms of dormancy and identify novel therapeutic strategies effective against antibiotictolerant bacterial infections.IMPORTANCE Dormancy is a protective state enabling bacteria to survive antibiotics, starvation, and the immune system. Dormancy is comprised of different states, including persistent and viable but nonculturable (VBNC) states that contribute to the spread of bacterial infections. Therefore, it is imperative to identify how bacteria utilize these different dormancy states to survive antibiotic treatment. The objective of our research is to eliminate dormancy as a route to antibiotic tolerance by understanding the proteins that control dormancy in Micrococcus luteus NCTC 2665. This bacterium has unique advantages for studying dormancy, including a small genome and a well-defined and reproducible VBNC state. Our experiments implicate four previously identified and 14 novel proteins upregulated in VBNC that may regulate this critical survival mechanism.KEYWORDS antibiotic tolerance, proteomics, stress response, systems biology D ormancy is a remarkable stress response in which bacteria curtail metabolic activity to survive potentially fatal external stresses. Dormancy has broad implications for many pathogenic bacteria, including Mycobacterium tuberculosis, Staphylococcus ...

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Role of catalase and oxyR in the viable but nonculturable state of Vibrio vulnificus

Cited by 135 publications

References 56 publications

In Situ and In Vitro Gene Expression by Vibrio vulnificus during Entry into, Persistence within, and Resuscitation from the Viable but Nonculturable State

In Situ and In Vitro Gene Expression by Vibrio vulnificus during Entry into, Persistence within, and Resuscitation from the Viable but Nonculturable State

Induction of Escherichia coli and Salmonella typhimurium into the viable but nonculturable state following chlorination of wastewater

A Proteomic Signature of Dormancy in the Actinobacterium Micrococcus luteus

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