Assembly of Complex Organelles: Pilus Biogenesis in Gram-Negative Bacteria as a Model System

Abstract Background:The study investigated if the disinfecting potential of Hypochlorous acid (HOCl) in suspensions are transferrable to in-air cleaning applications and to what extent aerosolized HOCl solutions can deactivate indoor microbial contaminations in-air at or below legal limits. Material and Method: For the liquid disinfection we used a standard suspension disinfection test protocol. For the in-air tests we conducted several experiments where aerosolized bacterial suspensions were injected into lab chambers preloaded with different HOCl gas concentrations. Results:In suspension experiments we found sufficient efficacies for all studied organisms at minimum concentrations of 200 ppm HOCl. The in-air measurement set-up allows to follow microbe deactivation by HOCl interaction. The deactivation rate increases with the HOCl concentration, and the values are highest for Gram-negative bacteria. Conclusion:We confirmed our hypothesis of the high disinfecting power of HOCl in-air at safe levels for populated indoor places. The investigated bacteria provide a model system for infectious particles, including enveloped viruses (to which Coronavirus belongs). These early results suggest that HOCl should be further evaluated as an air-cleaning method which may complement established concepts.

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A splash-reducing clinical handwash basin reduces droplet-mediated dispersal from a sink contaminated with Gram-negative bacteria in a laboratory model system

Journal of Hospital Infection ◽

10.1016/j.jhin.2021.04.017 ◽

2021 ◽

Author(s):

P. Aranega-Bou ◽

C. Cornbill ◽

N.Q. Verlander ◽

G. Moore

Keyword(s):

Model System ◽

Laboratory Model ◽

Gram Negative Bacteria ◽

Gram Negative

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Migration of Escherichia coli and Klebsiella pneumoniae Carbapenemase (KPC)-Producing Enterobacter cloacae through Wastewater Pipework and Establishment in Hospital Sink Waste Traps in a Laboratory Model System

Microorganisms ◽

10.3390/microorganisms9091868 ◽

2021 ◽

Vol 9 (9) ◽

pp. 1868

Author(s):

Paz Aranega-Bou ◽

Nicholas Ellaby ◽

Matthew J. Ellington ◽

Ginny Moore

Keyword(s):

Escherichia Coli ◽

Enterobacter Cloacae ◽

Model System ◽

Hospital Environment ◽

Laboratory Model ◽

Gram Negative Bacteria ◽

Drug Resistant ◽

Gram Negative ◽

Klebsiella Pneumoniae Carbapenemase ◽

Before And After

Sink waste traps and drains are a reservoir for multi-drug resistant Gram-negative bacteria in the hospital environment. It has been suggested that these bacteria can migrate through hospital plumbing. Hospital waste traps were installed in a laboratory model system where sinks were connected through a common wastewater pipe. Enterobacterales populations were monitored using selective culture, MALDI-TOF identification and antibiotic resistance profiling before and after a wastewater backflow event. When transfer between sinks was suspected, isolates were compared using whole-genome sequencing. Immediately after the wastewater backflow, two KPC-producing Enterobacter cloacae were recovered from a waste trap in which Carbapenemase-producing Enterobacterales (CPE) had not been detected previously. The isolates belonged to ST501 and ST31 and were genetically indistinguishable to those colonising sinks elsewhere in the system. Following inter-sink transfer, KPC-producing E. cloacae ST501 successfully integrated into the microbiome of the recipient sink and was detected in the waste trap water at least five months after the backflow event. Seven weeks and three months after the backflow, other inter-sink transfers involving Escherichia coli ST5295 and KPC-producing E. cloacae ST501 were also observed.

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A comprehensive guide to pilus biogenesis in Gram-negative bacteria

Nature Reviews Microbiology ◽

10.1038/nrmicro.2017.40 ◽

2017 ◽

Vol 15 (6) ◽

pp. 365-379 ◽

Cited By ~ 115

Author(s):

Manuela K. Hospenthal ◽

Tiago R. D. Costa ◽

Gabriel Waksman

Keyword(s):

Gram Negative Bacteria ◽

Gram Negative ◽

Pilus Biogenesis

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Migration of Escherichia coli and Klebsiella pneumoniae Carbapenemase (KPC)-Producing Enterobacter cloacae through Wastewater Pipework and Establishment in Hospital Sink Waste Traps in a Laboratory Model System

10.20944/preprints202107.0236.v1 ◽

2021 ◽

Author(s):

Paz Aranega-Bou ◽

Nicholas Ellaby ◽

Matthew J. Ellington ◽

Ginny Moore

Keyword(s):

Escherichia Coli ◽

Enterobacter Cloacae ◽

Model System ◽

Hospital Environment ◽

Laboratory Model ◽

Whole Genome ◽

Gram Negative Bacteria ◽

Drug Resistant ◽

Gram Negative ◽

Before And After

Sink waste traps and drains are a reservoir for multi-drug resistant Gram-negative bacteria in the hospital environment. It has been suggested that these bacteria can migrate through hospital plumbing. Hospital waste traps were installed in a laboratory model system where sinks were connected through a common wastewater pipe. Enterobacterales populations were monitored using selective culture, MALDI-TOF identification and antibiotic resistance profiling before and after a wastewater backflow event. When transfer between sinks was suspected, isolates were compared using whole-genome sequencing. Immediately after the wastewater backflow, two KPC-producing Enterobacter cloacae were recovered from a waste trap in which Carbapenemase-producing Enterobacterales (CPE) had not been detected previously. The isolates belonged to ST501 and ST31 and were genetically indistinguishable to those colonising sinks elsewhere in the system. Following inter-sink transfer, KPC-producing E. cloacae ST501 successfully integrated into the microbiome of the recipient sink and was detected in the waste trap water at least six months after the backflow event. Seven weeks and three months after the backflow, other inter-sink transfers involving Escherichia coli ST5295 and KPC-producing E. cloacae ST501 were also observed.

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Two-step and one-step secretion mechanisms in Gram-negative bacteria: contrasting the type IV secretion system and the chaperone-usher pathway of pilus biogenesis

Biochemical Journal ◽

10.1042/bj20091518 ◽

2010 ◽

Vol 425 (3) ◽

pp. 475-488 ◽

Cited By ~ 37

Author(s):

Ana Toste Rêgo ◽

Vidya Chandran ◽

Gabriel Waksman

Keyword(s):

Pathogenic Bacteria ◽

Cell Envelope ◽

Gram Negative Bacteria ◽

Secretion Systems ◽

Extracellular Medium ◽

Gram Negative ◽

Type Iv ◽

Pilus Biogenesis ◽

One Step ◽

Step Mechanism

Gram-negative bacteria have evolved diverse secretion systems/machineries to translocate substrates across the cell envelope. These various machineries fulfil a wide variety of functions but are also essential for pathogenic bacteria to infect human or plant cells. Secretion systems, of which there are seven, utilize one of two secretion mechanisms: (i) the one-step mechanism, whereby substrates are translocated directly from the bacterial cytoplasm to the extracellular medium or into the eukaryotic target cell; (ii) the two-step mechanism, whereby substrates are first translocated across the bacterial inner membrane; once in the periplasm, substrates are targeted to one of the secretion systems that mediate transport across the outer membrane and released outside the bacterial cell. The present review provides an example for each of these two classes of secretion systems and contrasts the various solutions evolved to secrete substrates.

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Bacterial-Mucosal Cell Junctional Complexes

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100050731 ◽

1974 ◽

Vol 32 ◽

pp. 144-145

Author(s):

Roger C. Wagner

Keyword(s):

Intestinal Wall ◽

Rat Colon ◽

Mucosal Cell ◽

Gram Negative Bacteria ◽

Gram Negative ◽

Mucosal Cells ◽

Mucosal Lining ◽

Degenerative Alterations ◽

Junctional Complexes ◽

Intestinal Mucosal Cells

Bacteria exhibit the ability to adhere to the apical surfaces of intestinal mucosal cells. These attachments either precede invasion of the intestinal wall by the bacteria with accompanying inflammation and degeneration of the mucosa or represent permanent anchoring sites where the bacteria never totally penetrate the mucosal cells.Endemic gram negative bacteria were found attached to the surface of mucosal cells lining the walls of crypts in the rat colon. The bacteria did not intrude deeper than 0.5 urn into the mucosal cells and no degenerative alterations were detectable in the mucosal lining.

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Rapid demonstration of septic or infectious arthritis due to Gram-negative bacteria

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100123830 ◽

1992 ◽

Vol 50 (1) ◽

pp. 686-687

Author(s):

Jacob S. Hanker ◽

Paul R. Gross ◽

Beverly L. Giammara

Keyword(s):

Chronic Arthritis ◽

Blood Cultures ◽

Gram Negative Bacteria ◽

Infectious Arthritis ◽

Bacterial Arthritis ◽

Gram Positive ◽

Gram Negative ◽

Gram Positive Bacteria

Blood cultures are positive in approximately only 50 per cent of the patients with nongonococcal bacterial infectious arthritis and about 20 per cent of those with gonococcal arthritis. But the concept that gram-negative bacteria could be involved even in chronic arthritis is well-supported. Gram stains are more definitive in staphylococcal arthritis caused by gram-positive bacteria than in bacterial arthritis due to gram-negative bacteria. In the latter situation where gram-negative bacilli are the problem, Gram stains are helpful for 50% of the patients; they are only helpful for 25% of the patients, however, where gram-negative gonococci are the problem. In arthritis due to gram-positive Staphylococci. Gramstained smears are positive for 75% of the patients.

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Ultrastructure of periplasmic bodies in gram-negative bacteria

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100160753 ◽

1990 ◽

Vol 48 (3) ◽

pp. 640-641

Author(s):

Xie Nianming ◽

Ding Shaoqing ◽

Wang Luping ◽

Yuan Zenglin ◽

Zhan Guolai ◽

...

Keyword(s):

Electron Microscope ◽

Campylobacter Jejuni ◽

Proteus Mirabilis ◽

Shigella Flexneri ◽

Morphological Description ◽

Gram Negative Bacteria ◽

Periplasmic Space ◽

Clostridium Tetani ◽

Gram Negative ◽

Brucella Canis

Perhaps the data about periplasmic enzymes are obtained through biochemical methods but lack of morphological description. We have proved the existence of periplasmic bodies by electron microscope and described their ultrastructures. We hope this report may draw the attention of biochemists and mrophologists to collaborate on researches in periplasmic enzymes or periplasmic bodies with each other.One or more independent bodies may be seen in the periplasmic space between outer and inner membranes of Gram-negative bacteria, which we called periplasmic bodies. The periplasmic bodies have been found in seven species of bacteria at least, including the Pseudomonas aeroginosa. Shigella flexneri, Echerichia coli. Yersinia pestis, Campylobacter jejuni, Proteus mirabilis, Clostridium tetani. Vibrio cholerae and Brucella canis.

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Dual stain kit for the microscopic gram classification of ocular infection bacteria

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100147089 ◽

1993 ◽

Vol 51 ◽

pp. 248-249

Author(s):

Jacob S. Hanker ◽

Dale N. Holdren ◽

Kenneth L. Cohen ◽

Beverly L. Giammara

Keyword(s):

Contact Lenses ◽

Ocular Infection ◽

Gram Negative Bacteria ◽

Gram Negative ◽

Gram Staining ◽

Ocular Infections ◽

Different Types ◽

Culture Positive ◽

Increased Susceptibility

Keratitis and conjunctivitis (infections of the cornea or conjunctiva) are ocular infections caused by various bacteria, fungi, viruses or parasites; bacteria, however, are usually prominent. Systemic conditions such as alcoholism, diabetes, debilitating disease, AIDS and immunosuppressive therapy can lead to increased susceptibility but trauma and contact lens use are very important factors. Gram-negative bacteria are most frequently cultured in these situations and Pseudomonas aeruginosa is most usually isolated from culture-positive ulcers of patients using contact lenses. Smears for staining can be obtained with a special swab or spatula and Gram staining frequently guides choice of a therapeutic rinse prior to the report of the culture results upon which specific antibiotic therapy is based. In some cases staining of the direct smear may be diagnostic in situations where the culture will not grow. In these cases different types of stains occasionally assist in guiding therapy.

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