The Chlamydiae: Infectious Aerosols in Indoor Environments

Cole, EC

doi:10.1520/stp25327s

Cited by 4 publications

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“…Personnel involved in the direct care of patients with respiratory diseases such as psittacosis from Chlamydia psittaci or pneumonia from Chlamydia pneumoniae are at risk of infection by the aerosol route. 17 During a psittacosis epidemic in Louisiana in 1943, there were 8 deaths among 19 diagnosed infections in nursing attendants. 18 The epidemiology of nosocomial legionnaires' disease has not been well elucidated.…”

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Characterization of infectious aerosols in health care facilities: An aid to effective engineering controls and preventive strategies

Cole

Cook

1998

American Journal of Infection Control

278

272

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Assessment of strategies for engineering controls for the prevention of airborne infectious disease transmission to patients and to health care and related workers requires consideration of the factors relevant to aerosol characterization. These factors include aerosol generation, particle size and concentrations, organism viability, infectivity and virulence, airflow and climate, and environmental sampling and analysis. The major focus on attention to engineering controls comes from recent increases in tuberculosis, particularly the multidrug-resistant varieties in the general hospital population, the severely immunocompromised, and those in at-risk and confined environments such as prisons, long-term care facilities, and shelters for the homeless. Many workers are in close contact with persons who have active, undiagnosed, or insufficiently treated tuberculosis. Additionally, patients and health care workers may be exposed to a variety of pathogenic human viruses, opportunistic fungi, and bacteria. This report therefore focuses on the nature of infectious aerosol transmission in an attempt to determine which factors can be systematically addressed to result in proven, applied engineering approaches to the control of infectious aerosols in hospital and health care facility environments. The infectious aerosols of consideration are those that are generated as particles of respirable size by both human and environmental sources and that have the capability of remaining viable and airborne for extended periods in the indoor environment. This definition precludes skin and mucous membrane exposures occurring from splashes (rather than true aerosols) of blood or body fluids containing infectious disease agents. There are no epidemiologic or laboratory studies documenting the transmission of bloodborne virus by way of aerosols.

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Characterization of infectious aerosols in health care facilities: An aid to effective engineering controls and preventive strategies

Cole

Cook

1998

American Journal of Infection Control

278

272

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“…Naturally occurring airborne microorganisms consist mostly of bacteria, fungi, and viruses (34). Knowledge of their sources, concentrations, and biological activity is of great importance because of their potential health effects (11). Currently, there are no direct-reading instruments that indicate the presence and concentration of microorganisms.…”

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Impaction onto a Glass Slide or Agar versus Impingement into a Liquid for the Collection and Recovery of Airborne Microorganisms

Juozaitis

Willeke

Grinshpun

et al. 1994

Appl Environ Microbiol

100

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To study impaction versus impingement for the collection and recovery of viable airborne microorganisms, three new bioaerosol samplers have been designed and built. They differ from each other by the medium onto which the bioaerosol particles are collected (glass, agar, and liquid) but have the same inlet and collection geometries and the same sampling flow rate. The bioaerosol concentrations recorded by three different collection techniques have been compared with each other: impaction onto a glass slide, impaction onto an agar medium, and impingement into a liquid. It was found that the particle collection efficiency of agar slide impaction depends on the concentration of agar in the collection medium and on the sampling time, when samples are collected on a nonmoving agar slide. Impingement into a liquid showed anomalous behavior with respect to the sampling flow rate. Optimal sampling conditions in which all three new samplers exhibit the same overall sampling efficiency for nonbiological particles have been established. Inlet and collection efficiencies of about 100% have been achieved for all three devices at a sampling flow rate of 10 liters/min. The new agar slide impactor and the new impinger were then used to study the biological factors affecting the overall sampling efficiency. Laboratory experiments on the total recovery of a typical environmental microorganism, Pseudomonas fluorescens ATCC 13525, showed that both sampling methods, impaction and impingement, provided essentially the same total recovery when relatively nonstressed microorganisms were sampled under optimal sampling conditions. Comparison tests of the newly developed bioaerosol samplers with those commercially available showed that the incorporation of our research findings into the design of the new samplers yields better performance data than data from currently available samplers.

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“…15,31,34 Chlamydial EB’s typically have a diameter of 0.25 to 0.35 μm and many species, including C. pneumoniae, C. psittaci, C. suis, C. pecorum, C. felis , and C. abortus , transmit through aerosolized droplets. 3,9,11,27,30,33,36,37 It is unclear as to whether Cm associated pulmonary disease follows gastrointestinal tract infection and replication, or can Cm be transmitted and infect the lungs directly via inhalation, e.g., as mice root in Cm-contaminated bedding. Disease transmission via aerosolization is categorized by type: droplet transmission, which involves particles larger than 5μm that settle to the ground within 1m of their generation, or airborne transmission, which involves particles smaller than 5μm that can remain suspended in the air for extended periods.…”

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confidence: 99%

Examining Intercage Transmission ofChlamydia muridarum: Impact of Barrier Husbandry and Cage Sanitization

Palillo,

Mishkin,

Aydin

et al. 2024

Preprint

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Chlamydia muridarum(Cm) has reemerged as a prevalent bacterial contaminant of academic research mouse colonies. A study was conducted to assess the effectiveness of husbandry and cage sanitization methods in preventing intercage transmission of Cm. To assess intercage transmission during cage change, a cage housing 2 Cm-free Swiss Webster (Tac:SW; SW) sentinel mice was placed randomly on each of 12 individually ventilated cage racks, housing cages with Cm-shedding mice, located in 1 of 2 animal holding rooms. Husbandry staff blinded to the study cages, changed all cages in the animal holding rooms weekly using microisolator cage technique. PCR testing performed 180 days post-placement confirmed all mice remained negative for Cm. To assess the effectiveness of cage sanitization to eliminate Cm, we investigated transmission of Cm to a naïve Cm-free SW and NOD.Cg-PrkdcscidIl2rgtm1Wjl/SzJ (NSG) mouse co-housed for 7 days (repeated weekly for 4 weeks) in cages assigned to 1 of 3 groups (n=10 pairs of mice/group). Cages that previously housed 2 Cm-shedding BALB/c mice were either washed in a tunnel washer (82.2°C [180°F] final rinse for an average of 16 seconds per run; n=10) with and without post-washing autoclaving (121°C for 20 minutes; n=10), or were untreated (bedding change only; n=10). Pre- and post-sanitization swabs of each cage were assayed for Cm by PCR. All pre-treatment swabs tested positive, while post-treatment swabs from all cages (excluding bedding change) tested negative. All SW and NSG mice, irrespective of group, remained negative for Cm as determined by PCR. These findings suggest that infectious Cm does not persist in untreated cages nor after mechanical washing with and without autoclaving. Collectively, these findings suggest that neither husbandry nor inadequate cage sanitization methods likely contributed to the observed prevalence of Cm in contemporary research mouse colonies.

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The Chlamydiae: Infectious Aerosols in Indoor Environments

Cited by 4 publications

References 0 publications

Characterization of infectious aerosols in health care facilities: An aid to effective engineering controls and preventive strategies

Characterization of infectious aerosols in health care facilities: An aid to effective engineering controls and preventive strategies

Impaction onto a Glass Slide or Agar versus Impingement into a Liquid for the Collection and Recovery of Airborne Microorganisms

Examining Intercage Transmission ofChlamydia muridarum: Impact of Barrier Husbandry and Cage Sanitization

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