Pantoea agglomerans: a marvelous bacterium of evil and good.Part I. Deleterious effects: Dust-borne endotoxins and allergens - focus on cotton dust.

The ubiquitous Gram-negative bacterium Pantoea agglomerans (synonyms: Enterobacter agglomerans, Erwinia herbicola) is known both as an epiphytic microbe developing on the surface of plants and as an endophytic organism living inside the plants. The bacterium occurs also abundantly in plant and animal products, in the body of arthropods and other animals, in water, soil, dust and air, and occasionally in humans. From the human viewpoint, the role of this organism is ambiguous, both deleterious and beneficial: on one side it causes disorders in people exposed to inhalation of organic dusts and diseases of crops, and on the other side it produces substances effective in the treatment of cancer and other diseases of humans and animals, suppresses the development of various plant pathogens, promotes plant growth, and appears as a potentially efficient biofertilizer and bioremediator. P. agglomerans was identified as a predominant bacterium on cotton plant grown all over the world, usually as an epiphyte, rarely as pathogen. It is particularly numerous on cotton bract after senescence. During processing of cotton in mills, bacteria and their products are released with cotton dust into air and are inhaled by workers, causing respiratory and general disorders, usually defined as byssinosis. The most adverse substance is endotoxin, a heteropolymer macromolecule present in the outermost part of the cell wall, consisting of lipopolysaccharide (LPS) as a major constituent, phospholipids and protein. The numerous experiments carried out in last quarter of XXth century on laboratory animals and human volunteers supported a convincing evidence that the inhaled endotoxin produced by P. agglomerans causes numerous pathologic effects similar to those elicited by cotton dust, such as influx of free lung cells into airways and activation of alveolar macrophages which secrete mediators (prostaglandins, platelet-activating factor, interleukin-1, tumor necrosis factor) that cause accumulation of platelets in pulmonary capillaries initiating an acute and chronic inflammation resulting in endothelial cell damage and extravasation of cells and fluids into the lung interstitium. These changes cause bronchoconstriction, the decrement of lung function expressed as reduction of forced expiratory volume in one second (FEV1) and/or diffusion capacity, increase in the airway hyperreactivity and subjective symptoms such as fever, airway irritation and chest tightness. The conclusions from these experiments, performed mostly 2-3 decades ago, did not loose their actuality until recently as so far no other cotton dust component was identified as a more important work-related hazard than bacterial endotoxin. Though also other microbial and plant constituents are considered as potential causative agents of byssinosis, the endotoxin produced by Pantoea agglomerans and other Gram-negative bacteria present in cotton dust is still regarded as a major cause of this mysterious disease.

The bacterial profile of cotton lint from worldwide origins, and links with occupational lung disease.

BACKGROUND: Byssinosis, the cotton worker's lung disease persists today in many countries. Several agents have been investigated with respect to causality; among these are Gram-negative bacteria. These organisms are a source of lipopolysaccharide toxins, which are potentially hazardous to the respiratory tract. Despite byssinosis being most prevalent in countries where adequate preventive procedures are lacking, the majority of past studies have been conducted on cotton from the United States. METHODS: The current investigation, involved the identification of Gram-negative bacteria from cotton lint samples originating in 12 world regions. RESULTS: The current investigation, involved the identification of Gram-negative bacteria from cotton lint samples originating in 12 world regions. CONCLUSIONS: Building a bacterial profile of cotton samples with worldwide origins will be useful in isolating sources of these organisms, assessing the risk posed to industry, workers and ultimately assisting the prevention of byssinosis and related conditions.

[Exposure to endotoxins in the environment. Occurrence and health hazards]. / Eksponering for endotoksiner i det ydre miljø. Forekomst og helbredsrisiko.

Endotoxins are lipopolysaccharides from the outer cell wall of Gram-negative bacteria. Exposure to endotoxins can take place in industries where organic material is handled, in agriculture, in garbage handling, and sewage treatment. Byssinosis defined as Monday chest tightness and slight dyspnoea in the work place has been related to endotoxin exposure in cotton mills, but studies indicate that similar symptoms may be found in other work places. Other symptoms are: Headache, nausea, gastrointestinal symptoms and influenza-like symptoms. Several studies have shown a decrease in FEV1 following exposure to endotoxins. The relationship between exposure to organic dust, microorganisms, endotoxins and other chemicals in the work place and disease needs further research.

Bacterial contamination of cotton as an indicator of respiratory effects among card room workers.

The influence of the bacterial contamination of cotton dust on the development of pulmonary symptoms has been investigated. The pulmonary function of card room workers in 23 US cotton mills was tested before and after the Monday working shift. A significant relation was found between the delta FEV1.0 decrement and the vertical elutriator dust level in the different mills. An improved correlation was obtained when the number of Gram-negative bacteria cultured from the bale cotton used in the different mills was employed in the exposure description. The results support earlier epidemiological and experimental studies, which demonstrate the importance of the Gram-negative bacteria in the development of pulmonary symptoms among workers in cotton mills.

Bacterial contamination of cotton and cotton dust and effects on the lung.

Bacterial contamination of various parts of the cotton plant and of cotton from different mills was investigated. The predominant bacterial species were Gram-negative rods mainly of the Enterobacter genus. When guinea pigs inhaled strains of these bacteria cultivated from cotton, a strong leucocyte mobilising capacity was found for Pseudomonas and Enterobacter but not for Agrobacterium or Bacillus species. The aetiology of the development of pulmonary symptoms after inhalation of bacteria-containing dusts and subsequent production of endotoxins is discussed.

Airborne micro-organisms and prevalence of byssinotic symptoms in cotton mills.

The concentration of airborne microbes, their endotoxins and the prevalence of byssinotic symptoms among workers were measured in the cardrooms of seven cotton spinning, a wool spinning and two cotton waste mills and in a dusty workroom of a group of five willowing mills, a tea-packing plant and a pipe tobacco factory. The concentration of microbes cultured on endoagar plates were found to correlate with byssinosis prevalence (r greater than 0.95, P less than 0.001). The concentration of nutrient agar microbes correlated with prevalence less well (r greater than 0.77, P less than 0.01) and that of fungi and endotoxins not at all.