[Bacteriology of the nose and sinuses]

The authors, on the basis of 140 cases, analyze the bacterial flora of essentially chronic rhino-sinusitis observed in hospital consultations at the Pellegrin Hospital, the referral centre of the Aquitaine region. Samples taken in the operating theatre from 100 cases, by aspiration and mucosal biopsy, were studied in aerobic and anaerobic media. The results marked by the scarcity of sterile samples and of anaerobic germs, evidence the predominance of an aerobic flora, with in particular Haemophilus influenzae, Staphylococcus aureus and beta-hemolytic Streptococci. No significant difference was recorded between the bacteriology of acute sinusitis as against chronic sinusitis. The flora of sinusitis appear to depend more on the age factor than on the pathogenic type. Branhamella catharralis is present only in patients under 30. The enterobacteria appear in the adult 30-50 year-old age group and, as from the age of 50, are combined by Pseudomonas aeruginosa, which account for 18% of the strains. These two types of germs then appear to be predominant over the Staphylococci and the Haemophilus.

Chemotaxis of alveolar macrophages and neutrophils in response to microbial products derived from organic dust

Mechanisms of chemotaxis of alveolar macrophages (AMs) and neutrophils (PMNs) in response to microbial products derived from organic dust were studied using the blindwell chemotaxis chamber technique. Seven different known etiological agents causing respiratory symptoms were used for experiments: cell extract and endotoxin from Pantoea agglomerans (synonyms: Erwinia herbicola, Enterobacter agglomerans), cell extracts from Thermoactinomyces vulgaris and Aspergillus fumigatus, protease from Bacillus thermoproteolyticus rokko and two preparations of glucans. These agents were evaluated for their ability to direct attraction of alveolar macrophages and neutrophils and stimulation of alveolar macrophages to release chemotactic factors for other alveolar macrophages and neutrophils. The microbial products were able to attract both alveolar macrophages and neutrophils directly in a dose-dependent manner, and the exposure of cultured alveolar macrophages to most agents stimulated chemotactic activity for for alveolar macrophages and neutrophils. The generation and release of this activity by alveolar macrophages may provide a mechanism for the initiation and amplification of inflammatory reactions in the lung after inhalation of organic dust. Results of these in vitro studies may be relevant to the pathogenesis of alveolitis in organic dust-induced lung diseases.

Chemotaxis of alveolar macrophages and neutrophils in response to microbial products derived from organic dust

The inhalation of organic dust has been implicated to cause a large number of occupational lung diseases. A common event in these diseases is an inflammatory reaction affecting airway and alveolar tissue that is characterized by the recruitment of different types of inflammatory cells. Mechanisms of chemotaxis of alveolar macrophages (AMs) and neutrophils (PMNs) in response to microbial products derived from organic dust were studied. Seven agents known to be etiological agents causing respiratory symptoms (extract and endotoxin of Enterobacter agglomerans, extracts from Thermoactinomyces vulgaris and Aspergillus fumigatus, thermophilic protease, and two preparations of glucans) were used for experiments. These agents were evaluated for their ability to directly attract AMs and PMNs and to stimulate alveolar macrophages to release chemotactic factors for other AMs and PMNs. The microbial products were able to attract both AMs and PMNs directly in a dose-dependent manner and the exposure of cultured AMs to most agents were stimulatory for production of chemotactic activity for AMs and PMNs. The generation and release of this activity by AMs may provide a mechanism for the initiation and amplification of inflammatory reactions in the lung after inhalation of organic dust. Results of these in vitro studies may be relevant to the pathogenesis of alveolitis in organic dust-induced lung diseases.

[Arachnids as risk factors in occupational exposure]

Arachnids pose two types of occupational hazard, mainly affecting agricultural and forestry workers. The first type is associated with bites of ticks, mites and spiders resulting in a local skin inflammation, systemic symptoms due to intoxication and the transmission of pathogenic viruses or bacteria, mainly caused by tick vectors. The second type is associated with the exposure to storage mites which cause asthma and rhinoconjunctivitis in farmers and grain workers.

Bacteria, fungi, and endotoxin as potential agents of occupational hazard in a potato processing plant

Workers in a potato processing plant were exposed at the particular workplace to large concentrations of airborne microorganisms and endotoxin. The presence of precipitins to microbial antigens was significantly correlated with the occurrence of the work-related respiratory and general symptoms that were found in 45.9% of the examined workers.

Increased superoxide anion generation by alveolar macrophages stimulated with antigens associated with organic dusts

The gaseous phase cultures of alveolar macrophages (AMs) of guinea pig were exposed to the saline extracts of the dust-borne bacteria Micropolyspora faeni (syn. Faenia rectivirgula) and Erwinia herbicola (syn. Enterobacter agglomerans) which have been added at the concentration of 1 microgram/ml to culture medium with or without complement. The effects of exposure on superoxide anion (O2-) production by AMs were assessed by the lucigenin-dependent chemiluminescence method. Both extracts caused significant (p less than 0.01) increase in O2- generation by AMs, as assessed by the 161-254% enhancement of chemiluminescence release comparing to control values. The presence of complement augmented the production of O2-, which reached a peak at 3 hrs after initial exposure. The possible significance of the generation of oxygen radicals in pathogenesis of the diseases due to exposure to agricultural dusts loaded with bacterial antigens is discussed.

Levels of bacteria, fungi, and endotoxin in bulk and aerosolized corn silage

Three samples of silage taken from the surface of a silo and from depths of 20 and 45 cm in the silo were studied for identification of the potential agents causing symptoms of organic dust toxic syndrome. The samples were examined by dilution plating before and after aerosolization in an acoustical dust generator. Aerosol samples were collected by liquid impinger and filter cassettes. The samples were examined for total aerobic bacteria, anaerobic bacteria, gram-negative bacteria, lactobacilli, listeriae, thermophilic actinomycetes, fungi, and endotoxin. Very high levels of total aerobic bacteria and fungi were found in the surface sample (up to 10(9) CFU/g in the bulk sample and up to 10(9) CFU/m3 after aerosolization), whereas the corresponding values from the deepest site were 100 to 50,000 times lower. Aspergillus fumigatus predominated among the fungi, whereas Bacillus and gram-negative organisms (Pseudomonas, Alcaligenes, Citrobacter, and Klebsiella species) prevailed among bacteria. Thermophilic actinomycetes occurred in numbers up to 10(7) CFU/g in the bulk samples, whereas anaerobic bacteria, lactobacilli, and listeriae were only few or absent. The concentration of endotoxin was high in the surface sample (up to 211.4 Endotoxin Units/mg) and about 200-fold lower in the sample from the deepest site. The results show that contact with dust from the surface of silage carries the risk of exposure to high concentrations of microorganisms, of which A. fumigatus and endotoxin-producing bacteria are the most probable disease agents.

Occupational biohazards: a review

There are at least 193 important biological agents that show infectious, allergenic, toxic, or carcinogenic activities in the working population. These agents are viruses, bacteria, fungi, plant substances, invertebrate animals (mostly arthropods), and substances derived from vertebrate animals. At least 20 large occupational groups are exposed to these biohazards. The risk is greatest among health care and laboratory workers who are threatened by human pathogens and among agricultural workers who are at risk from dust-borne biological allergens and toxins and by parasitic worms in warm climates. There is growing evidence that biohazards are also important risk factors for many other professions, including woodworkers, workers of textile plants, sewage and compost workers, miners and renovators. Some suggestions for research and prevention for reducing the occupational risks from biohazards are discussed.

A new simple controlled release delivery system

The chemical pulping of wood without subsequent drying affords low-cost hollow fibers with microporous multilamellar cell walls saturated with water. Simple impregnation of these never-dried pulp fibers with solutions of biologically active chemicals followed by drying yields collapsed cellulose ribbons containing entrapped impregnant. The release characteristics of exemplary composites containing an analgesic (acetylsalicylic acid), a growth stimulant (alpha-naphthylacetic acid), or a herbicide (2,4-dichlorophenoxyacetic acid) are reported both for in vitro and in vivo evaluations.

Hypersensitivity pneumonitis in grain farmers due to sensitization to Erwinia herbicola

Two cases of hypersensitivity pneumonitis in grain workers are described. Both cases had evidence of sensitization to the gram-negative bacteria Erwinia herbicola as judged by skin tests, detection of serum precipitins, and inhalation challenge. E. herbicola is frequently found in the microflora of grains.