Cell wall deficient forms: stealth pathogens

Mattman, L. H.

doi:10.1590/s1516-93322004000300028

Cited by 23 publications

(43 citation statements)

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“…[15][16][17][18][19][20] Under stress conditions mycobacteria can transform into L-forms, which undergo through various morphological stages and replicate by unusual modes. 15 Although not yet proven, we hypothesize that when BCG bacilli transform into L-forms, they probably cease to be immunogenic.…”

Section: Introductionmentioning

confidence: 99%

“…They exist as unusual morphological units, such as large and elementary bodies, vesicles, granules, filterable forms and others. [15][16][17][18][19][20] We found that BCG vaccine is able to produce under appropriate conditions filterable self-replicating L-form elements with virus-like size smaller than the size of bacterial filter pores of 0.2 mm.…”

Section: Introductionmentioning

confidence: 99%

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Mycobacterial L-forms are found in cord blood: A potential vertical transmission of BCG from vaccinated mothers

Маркова

Slavchev

Djerov

et al. 2016

Human Vaccines & Immunotherapeutics

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Our previous studies showed that mycobacterial L-forms persist in the blood of BCG vaccinated people and that BCG vaccine is able to produce, under appropriate conditions, filterable, self-replicating L-bodies with virus-like size. Because filterability is one of the characteristics of L-forms, considerable interest has been shown in their capacity to cross the maternal-fetal barrier. The current study demonstrated isolation of mycobacterial L-form cultures from umbilical cord blood of 5 healthy newborns of healthy mothers vaccinated previously with BCG. The isolated cultures showed distinctive growth characteristics of cell wall deficient L-form bacteria. Transmission electron microscopy demonstrated presence of L-bodies with extremely small size of 100 nm and revealed morphological transformations, typical for L-forms. IS6110 Real Time PCR assay confirmed that all L-form isolates were of mycobacterial origin and belonged to Mycobacterium tuberculosis complex which includes vaccinal BCG substrains. In conclusion, we could suggest that reproductive filterable L-bodies of BCG origin are able to fall in blood circulation of the fetus by vertical transmitted pathway and colonize newborns.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Mycobacterial L-forms are found in cord blood: A potential vertical transmission of BCG from vaccinated mothers

Маркова

Slavchev

Djerov

et al. 2016

Human Vaccines & Immunotherapeutics

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“…Although L-forms may be considered similar to bacterial protoplasts, they show a variable morphology characterized by an extreme pleomorphism, sometimes featuring a significantly enlarged diameter of 10-20 mm (Edman et al, 1968;Allan et al, 1993), compared with 1-3 mm for cells with walls. Other characteristics which distinguish L-forms from normal bacteria include specific growth requirements, loss of peptidoglycan (PG)-associated molecules and their functions, and intrinsic resistance to antibiotics interfering with cell wall synthesis such as the b-lactams (Brem and Eveland, 1967;Edman et al, 1968;Mattman, 2001). …”

Section: Introductionmentioning

confidence: 99%

“…L-forms apparently occur in both Gram-positive and Gram-negative bacteria, although it is not clear whether these mostly older reports (reviewed by Mattman, 2001 andMadoff, 1986) actually refer to a stable or a transient state of cell wall deficiency. Spontaneous transformation to the L-form phenotype has been reported in only few species, but L-form generation can often be stimulated by exposure to inhibitors of cell wall synthesis such as antibiotics, cell wall-hydrolysing enzymes, or amino acids such as glycine or lysine which in high concentrations can also interfere with PG synthesis (Maisnier-Patin and Richard, 1996).…”

Section: Introductionmentioning

confidence: 99%

Listeria monocytogenesl‐forms respond to cell wall deficiency by modifying gene expression and the mode of division

Dell'Era

Buchrieser

Couvé³

et al. 2009

Molecular Microbiology

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SummaryCell wall-deficient bacteria referred to as L-forms have lost the ability to maintain or build a rigid peptidoglycan envelope. We have generated stable, nonreverting L-form variants of the Gram-positive pathogen Listeria monocytogenes, and studied the cellular and molecular changes associated with this transition. Stable L-form cells can occur as small protoplast-like vesicles and as multinucleated, large bodies. They have lost the thick, multilayered murein sacculus and are surrounded by a cytoplasmic membrane only, although peptidoglycan precursors are still produced. While they lack murein-associated molecules including Internalin A, membraneanchored proteins such as Internalin B are retained. Surprisingly, L-forms were found to be able to divide and propagate indefinitely without a wall. Time-lapse microscopy of fluorescently labelled L-forms indicated a switch to a novel form of cell division, where genome-containing membrane vesicles are first formed within enlarged L-forms, and subsequently released by collapse of the mother cell. Array-based transcriptomics of parent and L-form cells revealed manifold differences in expression of genes associated with morphological and physiological functions. The L-forms feature downregulated metabolic functions correlating with the dramatic shift in surface to volume ratio, whereas upregulation of stress genes reflects the difficulties in adapting to this unusual, cell wall-deficient lifestyle.

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“…Far from the controversy generated about whether they really were M. tuberculosis or an environmental contaminant [41], or if they were really able to revert to the parent form or even to multiply [42], these forms seemed to be induced by the administration of antibiotics, as is the case with many other organisms [43]. Consequently, the lack of cell wall provides some advantage in the resistance against chemotherapeutic treatment by eliminating the targets to which the drugs are directed, although they would be more susceptible to changes in the environment and the chances to survive in an inflammatory area would be even lower.…”

Section: Experiments In Vitromentioning

confidence: 99%

On the nature of Mycobacterium tuberculosis-latent bacilli

Cardona¹

2004

European Respiratory Journal

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On the nature of Mycobacterium tuberculosis-latent bacilli. P-J. Cardona, J. Ruiz-Manzano. #ERS Journals Ltd 2004. ABSTRACT: Mycobacterium tuberculosis-latent bacilli are microorganisms that adapt to stressful conditions generated by the infected host against them. By slowing metabolism or becoming dormant, they may counterbalance these conditions and appear as silent to the immune system. Moreover, the dynamic turnover of the infected cells provokes a constant reactivation of the latent bacilli when the environmental conditions are favourable, or an activation after being dormant in necrotic and fibrotic lesions for a long period of time. Since there is no in vivo nor in vitro evidence for quick resuscitation of dormant bacilli, the current authors strongly favour the possibility that latent tuberculosis infection can be maintained for no longer than y10 yrs, which is, nowadays, a time period very close to that considered for "primary" tuberculosis. This concept may also be helpful for newer epidemiological considerations regarding the real impact of reinfection in tuberculosis.

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Cell wall deficient forms: stealth pathogens

Cited by 23 publications

References 0 publications

Mycobacterial L-forms are found in cord blood: A potential vertical transmission of BCG from vaccinated mothers

Mycobacterial L-forms are found in cord blood: A potential vertical transmission of BCG from vaccinated mothers

Listeria monocytogenesl‐forms respond to cell wall deficiency by modifying gene expression and the mode of division

On the nature of Mycobacterium tuberculosis-latent bacilli

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