Gram-Positive Bacteria in the Marine Environment

Lleò, Maria del Mar; Signoretto, Caterina; Canepari, Pietro

doi:10.1007/0-387-23709-7_13

Cited by 6 publications

(4 citation statements)

References 77 publications

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“…The VBNC state is a survival strategy adopted by many bacteria when exposed to stressing conditions (Roszak and Colwell, 1987; Colwell, 2000). The fact that bacteria in this state maintain their viability but are no longer culturable on conventional growth media poses serious risk for human health, in that they could act as possible infectious agents (Colwell, 1996; Huq et al ., 2000; Oliver, 2000; Lleò et al ., 2006). In this case, the possible response to antimicrobial therapy could be questionable.…”

Section: Discussionmentioning

confidence: 99%

“…Repercussions of the existence of the VBNC state are observed in both clinical and environmental microbiology. A certain amount of evidence has been accumulated regarding the role of VBNC bacteria as an important reservoir of human pathogens in natural environments such as fresh or marine waters (Byrd et al ., 1991; Huq et al ., 2000; Gil et al ., 2004; Signoretto et al ., 2004; He and Jiang, 2005; Lleò et al ., 2006). It has been suggested that the culture methods currently used to evaluate the microbiological quality of environmental samples may underestimate the real bacterial load in that they are incapable of detecting VBNC bacteria (Colwell, 1996; Oliver, 2000; Huq et al ., 2000; Signoretto et al ., 2004; Lleò et al ., 2006).…”

Section: Introductionmentioning

confidence: 99%

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Inhibition of the resuscitation from the viable but non‐culturable state in Enterococcus faecalis

Lleò

Benedetti

Tafi

et al. 2007

Environmental Microbiology

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The viable but non-culturable (VBNC) state is a survival strategy adopted by bacteria when exposed to environmental stresses capable of inducing cell growth inhibition and cell death. This state can be summarized as a quiescent form of life waiting for suitable conditions. This strategy has been shown to be activated by medically important bacteria either when present in natural environments or in the human body during the infection process. In this study we have evaluated the effects of antibiotics acting on peptidoglycan or protein synthesis of Enterococcus faecalis in the VBNC state. The activity of the antibiotics was determined by their ability both to inhibit resuscitation (i.e. recovery of cell division) and to bind the molecular target of action. Benzylpenicillin, piperacillin and gentamicin block cell resuscitation at the minimal inhibitory concentrations (MICs) of growing cells, while vancomycin acts only at doses 500 times higher than the MIC. This different behaviour is discussed taking into consideration the mode of action of the antibiotics.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Inhibition of the resuscitation from the viable but non‐culturable state in Enterococcus faecalis

Lleò

Benedetti

Tafi

et al. 2007

Environmental Microbiology

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“…Enterococcus faecalis, like other nonsporulating bacteria, can respond to environmental stressors by altering its physiology to a starvation state whereby it persists without growing in the environment and is recovered by culture (45), or to a distinctly different viable but nonculturable (VBNC) state whereby cells are vegetative and not culturable, but can be visualized with viable count methods (46). Studies of the viability of E. faecalis in artificial seawater microcosms show that at least 80% of the cells remain viable when colonies can no longer be recovered (47), suggesting that VBNC ENT may persist in a dormant state in the environment. Likewise, in marine waters, enterotoxigenic EC strains have been documented entering the VBNC state upon exposure to sunlight, and subsequently persisting in the environment while retaining toxicity (48).…”

Section: New Perspectives On Fecal Indicators In the Environmentmentioning

confidence: 99%

Bacteria in Beach Sands: An Emerging Challenge in Protecting Coastal Water Quality and Bather Health

Halliday

Gast

2010

Environ. Sci. Technol.

157

112

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To protect bather health at recreational beaches, fecal indicator bacterial standards are used to monitor water quality, and waters exceeding the standards are subsequently closed to bathers. However beachgoers are also in contact with beach sands, the sanitary quality of which is not included within beach monitoring programs. In fact, sands and sediments provide habitat where fecal bacterial populations may persist, and in some cases grow, in the coastal zone. Specific pathogens are less well studied in beach sands and sediments, but there is a body of evidence that they too may persist in these environments. This paper reviews the current state of knowledge regarding the abundance and distribution of fecal indicator bacteria and pathogens in beach sands of diverse climatological regions, and at beaches subjected to varied levels of anthropogenic impact. In all regions fecal indicator bacteria are nearly ubiquitous in beach sands, and similar relationships emerge between fecal indicator abundance in dry sand, submerged sands, and water. Taken together, these studies contextualize a potential public health issue and identify research questions that must be addressed in order to support future policy decisions.

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“…Listeria monocytogenes, and Enterococcus faecalis have been described to infect humans through the consumption of contaminated water or seafood are therefore part of water pathogens [3]. Te Gram-negative bacteria involved in this study are Escherichia coli, Pseudomonas aeruginosa, and Salmonella Typhi which have been described as pathogens involved in waterborne diseases [56]. Candida species including Candida albicans and Candida tropicalis together with other opportunistic yeasts have been detected in polluted waters [57].…”

Section: Characterization Of Hydrated Zirconium Oxide-coatedmentioning

confidence: 85%

Antibiofilm and Anti-Quorum Sensing Potential of Safely-Synthesized Hydrated Zirconium Oxide-Coated Alginate Beads against Some Pathogenic Bacteria

Tamfu,

Dogaç,

Ceylan

et al. 2023

Journal of Chemistry

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Water is essential to life, but access to uncontaminated water remains a global challenge. Metal oxides possess particular characteristics required for removing heavy metals, inorganic and organic pollutants from wastewater as well as inhibiting microorganisms. Zirconium oxide and alginate which are nontoxic materials were used to synthesize hydrated zirconium oxide-alginate coated materials, ZAB-1 (1.5% alginate) and ZAB-2 (2.0% alginate). FT-IR was used to characterize the functional groups while surface morphology was characterized using SEM. XRD was used to characterize the material structure of the resulting composite. Against Chromobacterium violaceum CV12472, minimal inhibitory concentrations (MICs) were 0.625 mg/mL for ZAB-1 and ZAB-2 while against C. violaceum CV026, the MIC values were 0.625 mg/mL and 1.25 mg/mL for ZAB-1 and ZAB-2, respectively. At MIC and sub-MIC concentrations, the synthesized beads inhibited the production of violacein in C. violaceum CV12472 and C. violaceum CV026, indicating that they can reduce QS-mediated virulence factors in bacteria. Antimicrobial activity was evaluated against Staphylococcus aureus, Enterococcus faecalis, Listeria monocytogenes, Escherichia coli, Pseudomonas aeruginosa, Salmonella typhi, Candida albicans, and Candida tropicalis, and MIC values ranged from 1.25 mg/mL to 10 mg/mL. Biofilm inhibition percentages were relatively high against S. aureus, E. coli, and C. albicans. It is observed that the increase in the alginate amount from 1.5% to 2.0% improves the antimicrobial, anti-QS, and antibiofilm effects. The alginate makes the zirconium oxide particles biocompatible and easily recoverable from water after treatment. ZAB-1 and ZAB-2 materials can therefore be sustainable materials for water treatment since it can inhibit pathogenic bacteria in water and equally satisfy environmental friendliness. The synthesized particles reduced the chances for antimicrobial resistance since they disrupted QS in bacteria and eliminated biofilms, thereby preventing biofouling of microbial communities in water. Future prospects of this study involve biofiltration, that is, the use of the synthesized composite in the development of a safe and compatible biofilter for water purification.

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Gram-Positive Bacteria in the Marine Environment

Cited by 6 publications

References 77 publications

Inhibition of the resuscitation from the viable but non‐culturable state in Enterococcus faecalis

Inhibition of the resuscitation from the viable but non‐culturable state in Enterococcus faecalis

Bacteria in Beach Sands: An Emerging Challenge in Protecting Coastal Water Quality and Bather Health

Antibiofilm and Anti-Quorum Sensing Potential of Safely-Synthesized Hydrated Zirconium Oxide-Coated Alginate Beads against Some Pathogenic Bacteria

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