Subacute inhalation toxicity study of an ice-nucleation-active Pseudomonas syringae administered as a respirable aerosol to rats

Kohan

Gilmour

et al. 1993

Appl Environ Microbiol

The environmental release of engineered microorganisms has caused health and environmental concerns. In this study, an animal model was used to examine health effects following pulmonary exposure to environmental and clinical isolates. In order to rule out the possibility that an adverse response was caused by endotoxin, 50%Yo lethal doses (ID50) were determined, when possible, with endotoxin-sensitive (C3HeB/FeJ) and endotoxinresistant (C3H/HeJ) mice by using both environmental isolates (Pseudomonas aeruginosa BC16, BC17, BC18, and AC869 and Pseudomonas maltophUia BC6) and clinical isolates (P. aeruginosa PAO1 and DG1). The LDIo of strains AC869, DG1, and PAO1 are 1.05 x 107, 6.56 x 106, and 1.02 x 107 CFU, respectively, in C3HeB/FeJ mice and 1.05 x 107, 1.00 X 107, and 2.75 x 106 CFU, respectively, in C3H/HeJ mice. Strains BC17 and BC18 were not lethal to the animals. On the basis of the LDI50 data, an appropriate sublethal dose (approximately 106 CFU) was selected. Animals were challenged intranasaily with microorganisms, and clearance from the lungs and nasal cavity was determined. Strains BC17, BC18, and AC869 were not detected in lungs or nasal washes 14 days following treatment. Strains BC6, BC16, and DG1 were recovered from the nasal cavities at the end of the experiment. Only strain PAO1 was detected in lungs and in nasal cavities 14 days after treatment. At selected intervals following treatment, the percentages of polymorphonuclear leukocytes and lymphocytes in bronchoalveolar lavage samples were determined. P. aeruginosa AC869, PAO1, and DG1 elicited a relatively strong inflammatory response which was indirectly related to lung clearance. An intermediate response was observed in the lungs of animals challenged with P. malophUia BC6 and P. aeruginosa BC16 and BC17. A significant increase in the ratio of lung weight to body weight was observed in strain AC869-treated animals. Our data indicate that upon intranasal exposure P. aeruginosa AC869 has the potential to induce adverse health effects in mice, as shown by lung and nasal cavity clearance and the pulmonary inflammatory response.

Section: Discussionmentioning

confidence: 94%

“…Both rat (6,14,18,39) and mouse (12, 39, 41) models have been used to study health effects following pulmonary exposure to pseudomonads. Intranasal exposure and intratracheal exposure have been used in a reproducible surrogate infection model for acute microbial pulmonary exposure studies in mice (37).…”

mentioning

confidence: 99%

Pulmonary clearance and inflammatory response in C3H/HeJ mice after intranasal exposure to Pseudomonas spp

Kohan

Gilmour

et al. 1993

Appl Environ Microbiol

“…Several laboratories have addressed issues associated with adverse health effects following exposure to biological products and by-products (10). In 6itro and in 6i6o models used to assess adverse health effects following oral and pulmonary exposure to biotechnology agents have been developed and evaluated (15,(20)(21)(22)(23)(24). A tier approach to determine the respiratory allergenicity potential of low molecular weight chemicals, such as the microbial product alcalase has been described (11).…”

Section: Resultsmentioning

confidence: 99%

“…However, if a particular strain causes adverse health effects in an animal model, manufacturers and applicators can be alerted and take the necessary precautions during potential exposure stages of the process. Animal models have been used by several investigators to predict human toxicity upon exposure to pseudomonads including P. putida (41), P. syringae (21,42) and P. aeruginosa (39,43,44), as well as other biotechnological agents such as Bacillus thuringiensis subsp. israelensis (22,23) and Mycobacterium sp.…”

Section: Translocation Of Pseudomonas Spp and B Cepacia In 6i6omentioning

confidence: 99%

Survival of Environmental Microbial Agents in CD-1 Mice Following Oral Exposure

Microbial Ecology in Health and Disease

2000

Microbial agents have many applications in the environment and are replacing chemicals and engineering processes due to improved efficacy, reduced toxicity, and less cost. Typically, innocuous species are used, however, unless the products include genetically engineered microorganisms, potential health effects are not scrutinized. In order to investigate possible health concerns, four surrogate microbial agents were studied in 6i6o and in 6itro. Male CD-1 mice were treated perorally (p.o.) with average doses of 2.62 × 10 8 colony forming units (CFU) of Pseudomonas aureofaciens, 1.16 × 10 8 CFU of Burkholderia cepacia, 1.78× 10 8 CFU of P. fluorescens, or 1.86 ×10 8 CFU of P. putida. To determine clearance of the dosed strains from mice, lungs, intestinal tract (small, large, cecum), mesenteric lymph nodes (MLN), spleen, and liver were homogenized individually, and dilutions inoculated onto selective media for enumeration of intestinal populations. All strains were recovered in the intestinal tract 3 hours after treatment but P. fluorescens and P. aureofaciens were cleared after the first day. P. putida and B. cepacia survived for at least 2 days in the large intestine and B. cepacia was detected in the small intestine 7 days after treatment. P. aureofaciens and B. cepacia were isolated from the lungs for 2 and 7 days. All strains translocated to the MLN and were detected 3 hours after treatment. B. cepacia was isolated from the spleen and liver 3 hours post-treatment. P. aureofaciens and P. putida translocated to the liver within 3 hours of treatment and P. fluorescens translocated to the spleen. None of the dosed strains were detected extraintestinally after 3 hours. All strains were eliminated from in 6itro intestinal continuous cultures. The models described in this study facilitate the identification of potential human safety issues associated with biotechnology agents.

“…Because biotechnological applications require production and environmental application of high concentrations of microorganisms, it is important to determine whether adverse health effects may occur upon pulmonary exposure to these strains. For example, snow gun dispersions contain 0.8 x 109 to 1.6 x 109 CFU of viable and nonviable P. syringae per liter, but particles are generally regarded as nonrespirable (10). It is possible that strain engineering may alter expression of pathogenic factors and, depending on the exposure route, may cause a detrimental effect.…”

mentioning

confidence: 99%

Distribution, clearance, and mortality of environmental pseudomonads in mice upon intranasal exposure

Kohan

Whitehouse

et al. 1991

Appl Environ Microbiol