Cell Wall-Deficient Bacteria as a Cause of Infections: A Review of the Clinical Significance

Onwuamaegbu, ME; Belcher, RA; Soare, C

doi:10.1177/147323000503300101

Cited by 56 publications

(51 citation statements)

References 106 publications

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“…Indeed, cell wall-deficient microorganisms such as "L-form" bacteria and yeast spheroplasts (created in the lab by inhibiting cell wall synthesis or enzymatically damaging the cell wall) are nonculturable in standard nonisotonic laboratory media (21). The risk of producing VBNC phenotypes is generally reduced with longer plasma exposure (2), which, as demonstrated in this study, continues to damage the cell surface and lead to partial or complete cell lysis.…”

Section: Discussionmentioning

confidence: 66%

Nonthermal Atmospheric Plasma Rapidly Disinfects Multidrug-Resistant Microbes by Inducing Cell Surface Damage

Kvam

Davis

Mondello

et al. 2012

Antimicrob Agents Chemother

160

111

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Plasma, a unique state of matter with properties similar to those of ionized gas, is an effective biological disinfectant. However, the mechanism through which nonthermal or "cold" plasma inactivates microbes on surfaces is poorly understood, due in part to challenges associated with processing and analyzing live cells on surfaces rather than in aqueous solution. Here, we employ membrane adsorption techniques to visualize the cellular effects of plasma on representative clinical isolates of drug-resistant microbes. Through direct fluorescent imaging, we demonstrate that plasma rapidly inactivates planktonic cultures, with >5 log 10 kill in 30 s by damaging the cell surface in a time-dependent manner, resulting in a loss of membrane integrity, leakage of intracellular components (nucleic acid, protein, ATP), and ultimately focal dissolution of the cell surface with longer exposure time. This occurred with similar kinetic rates among methicillin-resistant Staphylococcus aureus (MRSA), Pseudomonas aeruginosa, and Candida albicans. We observed no correlative evidence that plasma induced widespread genomic damage or oxidative protein modification prior to the onset of membrane damage. Consistent with the notion that plasma is superficial, plasma-mediated sterilization was dramatically reduced when microbial cells were enveloped in aqueous buffer prior to treatment. These results support the use of nonthermal plasmas for disinfecting multidrug-resistant microbes in environmental settings and substantiate ongoing clinical applications for plasma devices. P lasmas are ionized gases that exhibit a plethora of applied temperature and physical properties. In biomedical applications, plasmas are supported by an electric field such that electrons receive external energy more rapidly than surrounding ions (5). Plasmas generate thermal energy (heat) when heavy particle temperatures equilibrate with electron temperature but are considered "nonthermal" when the cooling of ions and uncharged molecules is more effective than the energy transfer from electrons to gas (5). Nonthermal or "cold" plasmas produce a variety of shortlived and long-lived reactive components, including charged particles and UV radiation, without significantly raising temperature (25). Nonthermal plasmas (NTPs) are applied extensively in materials science to modify the properties of carbon-based materials but have also shown promise for applications in biology and med-

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Section: Discussionmentioning

confidence: 66%

Nonthermal Atmospheric Plasma Rapidly Disinfects Multidrug-Resistant Microbes by Inducing Cell Surface Damage

Kvam

Davis

Mondello

et al. 2012

Antimicrob Agents Chemother

160

111

View full text Add to dashboard Cite

show abstract

“…This is intriguing, in particular in regard to numerous studies on experimental infections claiming a possible role for L-forms in diseases such as endocarditis, rheumatic fever, Crohn's disease, sarcoidosis, septicemia, urinary tract infections, or chronic gastritis (Owens, 1987; Markova et al, 1997; Michailova et al, 2000, 2007). However, direct evidence for a role of L-forms in disease is still missing, as re-isolation from an infected host has not yet been reported (Onwuamaegbu et al, 2005). Generally, investigation of the pathogenic properties of L-forms originating from pathogens is needed to determine their potential role in human disease.…”

Section: Introductionmentioning

confidence: 99%

Cell-wall deficient L. monocytogenes L-forms feature abrogated pathogenicity

Schnell¹,

Staubli²,

Harris

et al. 2014

Front. Cell. Infect. Microbiol

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Stable L-forms are cell wall-deficient bacteria which are able to multiply and propagate indefinitely, despite the absence of a rigid peptidoglycan cell wall. We investigated whether L-forms of the intracellular pathogen L. monocytogenes possibly retain pathogenicity, and if they could trigger an innate immune response. While phagocytosis of L. monocytogenes L-forms by non-activated macrophages sometimes resulted in an unexpected persistence of the bacteria in the phagocytes, they were effectively eliminated by IFN-γ preactivated or bone marrow-derived macrophages (BMM). These findings were in line with the observed down-regulation of virulence factors in the cell-wall deficient L. monocytogenes. Absence of Interferon-β (IFN-β) triggering indicated inability of L-forms to escape from the phagosome into the cytosol. Moreover, abrogated cytokine response in MyD88-deficient dendritic cells (DC) challenged with L. monocytogenes L-forms suggested an exclusive TLR-dependent host response. Taken together, our data demonstrate a strong attenuation of Listeria monocytogenes L-form pathogenicity, due to diminished expression of virulence factors and innate immunity recognition, eventually resulting in elimination of L-form bacteria from phagocytes.

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“…However, a lot of papers, reviews (Allan et al, 2009;Beran et al, 2006;Domingue and Woody, 1997;Domingue, 2010;Gumpert & Taubeneck, 1983;Onwuamaegbu et al, 2005;Zhang, 2004) and several monographs (Domingue, 1982;Mattman, 2001;Prozorovski et al, 1981), support the concept that L-forms can be induced in vivo, can persist there for a significant span of time and can be the cause for latent, chronic and relapsing/recurrent infections, as well as for diseases of unknown infectious-allergic or autoimmune origin.…”

Section: Clinical Significance and Role Of Mycobacterial L-formsmentioning

confidence: 99%

Cell Wall Deficiency in Mycobacteria: Latency and Persistence

Маркова¹

2012

Understanding Tuberculosis - Deciphering the Secret Life of the Bacilli

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Cell Wall-Deficient Bacteria as a Cause of Infections: A Review of the Clinical Significance

Cited by 56 publications

References 106 publications

Nonthermal Atmospheric Plasma Rapidly Disinfects Multidrug-Resistant Microbes by Inducing Cell Surface Damage

Nonthermal Atmospheric Plasma Rapidly Disinfects Multidrug-Resistant Microbes by Inducing Cell Surface Damage

Cell-wall deficient L. monocytogenes L-forms feature abrogated pathogenicity

Cell Wall Deficiency in Mycobacteria: Latency and Persistence

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