Airborne coliphages from wastewater treatment facilities

SARS-CoV-2 air sampling: A systematic review on the methodologies for detection and infectivity

This systematic review aims to present an overview of the current aerosol sampling methods (and equipment) being used to investigate the presence of SARS-CoV-2 in the air, along with the main parameters reported in the studies that are essential to analyze the advantages and disadvantages of each method and perspectives for future research regarding this mode of transmission. A systematic literature review was performed on PubMed/MEDLINE, Web of Science, and Scopus to assess the current air sampling methodologies being applied to SARS-CoV-2. Most of the studies took place in indoor environments and healthcare settings and included air and environmental sampling. The collection mechanisms used were impinger, cyclone, impactor, filters, water-based condensation, and passive sampling. Most of the reviewed studies used RT-PCR to test the presence of SARS-CoV-2 RNA in the collected samples. SARS-CoV-2 RNA was detected with all collection mechanisms. From the studies detecting the presence of SARS-CoV-2 RNA, fourteen assessed infectivity. Five studies detected viable viruses using impactor, water-based condensation, and cyclone collection mechanisms. There is a need for a standardized protocol for sampling SARS-CoV-2 in air, which should also account for other influencing parameters, including air exchange ratio in the room sampled, relative humidity, temperature, and lighting conditions.

An Appraisal of Bacteriophage Isolation Techniques from Environment

Researchers have recently renewed interest in bacteriophages. Being valuable models for the study of eukaryotic viruses, and more importantly, natural killers of bacteria, bacteriophages are being tapped for their potential role in multiple applications. Bacteriophages are also being increasingly sought for bacteriophage therapy due to rising antimicrobial resistance among pathogens. Reports show that there is an increasing trend in therapeutic application of natural bacteriophages, genetically engineered bacteriophages, and bacteriophage-encoded products as antimicrobial agents. In view of these applications, the isolation and characterization of bacteriophages from the environment has caught attention. In this review, various methods for isolation of bacteriophages from environmental sources like water, soil, and air are comprehensively described. The review also draws attention towards a handful on-field bacteriophage isolation techniques and the need for their further rapid development.

Allergic Bronchopulmonary Mycosis due to Exposure to Eurotium herbariorum after the Great East Japan Earthquake

BACKGROUND

Indoor mold levels typically increase after natural disasters, flooding, and water damage. Eurotium herbariorum is the sexual stage of Aspergillus glaucus. Case Presentation A 66-year-old, Japanese male, ex-smoker had been diagnosed with bronchial asthma when he was five years old; he achieved remission at the age of 13 years. He was displaced from his home during the Great East Japan Earthquake on March 11, 2011 and moved to temporary housing in Miyagi Prefecture in June 2011. He experienced the first episode of chest tightness, coughing, and wheezing in February 2012, when he again was diagnosed as having bronchial asthma. Mycofloral surveillance detected high counts of Eurotium in the air of his bedroom, kitchen, and living room, with a maximal fungal count of 163,200 colony-forming units per cubic meter (CFU/m3). Although Cladosporium and Penicillium typically predominate in the indoor air of residential dwellings, only low levels of these organisms were present in the patient's home. Morphologic identification confirmed the isolates as E. herbariorum. The patient had positive reactions to E. herbariorum in skin prick testing and the presence of antigen-specific precipitating antibodies to E. herbariorum. Computed tomography of the chest in August 2013 revealed central bronchiectasis and bronchial wall thickening. The patient experienced late reactions after provocation testing with E. herbariorum.

CONCLUSION

This report presents the rare case of a patient who developed allergic bronchopulmonary mycosis (ABPM) due to exposure to E. herbariorum during temporary housing after the Great East Japan Earthquake. Oshikata C , Watanabe M , Saito A , Ishida M , Kobayashi S , Konuma R , Kamata Y , Terajima J , Cho J , Yanai M , Tsurikisawa N . Allergic bronchopulmonary mycosis due to exposure to eurotium herbariorum after the Great East Japan Earthquake. Prehosp Disaster Med. 2017;32(6):688-690.

Methods for sampling of airborne viruses

To better understand the underlying mechanisms of aerovirology, accurate sampling of airborne viruses is fundamental. The sampling instruments commonly used in aerobiology have also been used to recover viruses suspended in the air. We reviewed over 100 papers to evaluate the methods currently used for viral aerosol sampling. Differentiating infections caused by direct contact from those caused by airborne dissemination can be a very demanding task given the wide variety of sources of viral aerosols. While epidemiological data can help to determine the source of the contamination, direct data obtained from air samples can provide very useful information for risk assessment purposes. Many types of samplers have been used over the years, including liquid impingers, solid impactors, filters, electrostatic precipitators, and many others. The efficiencies of these samplers depend on a variety of environmental and methodological factors that can affect the integrity of the virus structure. The aerodynamic size distribution of the aerosol also has a direct effect on sampler efficiency. Viral aerosols can be studied under controlled laboratory conditions, using biological or nonbiological tracers and surrogate viruses, which are also discussed in this review. Lastly, general recommendations are made regarding future studies on the sampling of airborne viruses.

Animal viruses, coliphages, and bacteria in aerosols and wastewater at a spray irrigation site

Aerosol samples collected at the Muskegon County Wastewater Management System Number 1 spray irrigation site in Michigan by using the Army prototype XM2 Biological Sampler/Collector were examined for the presence of animal viruses, coliphages, and bacteria. Air samples, collected in Earle lactalbumen hydrolysate, and wastewater samples were filtered through a 0.45- and 1.2-micron membrane filter sandwich, pretreated with 10% beef extract (pH 7.0), and assayed for animal viruses by the plaque method on Buffalo green monkey kidney cells. Untreated air and wastewater samples were assayed for coliphages by the soft agar overlay method with three Escherichia coli hosts (ATCC 13706, 15597, and 11303) and for bacteria by the heterotrophic plate count method. Filtered air samples were assayed for coliphages by the most-probable-number method with the same three hosts. Although no animal viruses were detected in the aerosol samples, coliphages and bacteria were recovered. E. coli ATCC 13706 coliphage were recovered more often and in greater numbers than either of the other two types of coliphages. Concentrations of animal viruses, coliphages, and bacteria detected in the raw influent decreased as the wastewater was aerated and stored in the lagoons. No animal viruses were detected in the wastewater at the pump station just before distribution to the spray irrigation rigs. The most-probable-number method was more sensitive and consistent than the overlay procedure in detecting low levels of coliphages in air samples.

Effect of an activated sludge wastewater treatment plant on ambient air densities of aerosols containing bacteria and viruses

Bacteria- and virus-containing aerosols were studied during the late summer and fall seasons in a midwestern suburb of the United States before and during the start-up and operation of an unenclosed activated sludge wastewater treatment plant. The study showed that the air in this suburban area contained low-level densities of indicator microorganisms. After the plant began operating, the densities of total aerobic bacteria-containing particles, standard plate count bacteria, total coliforms, fecal coliforms, fecal streptococci, and coliphages increased significantly in the air within the perimeter of the plant. Before plant operations, bacteria were detected from five genera, Klebsiella, Enterobacter, Serratia, Salmonella, and Aeromonas. During plant operations, the number of genera identified increased to 11. In addition to those genera found before plant operations, Escherichia, Providencia, Citrobacter, Acinetobacter, Pasteurella, and Proteus, were also identified. Enteric viruses were detected in low densities from the air emissions of this plant. Only standard plate count bacteria remained at significantly higher than base-line densities beyond 250 m downwind from the center of the aeration tanks. Fecal streptococci and coliphages appeared to be more stable in aerosols than the other indicator microorganisms studied. In general, the densities of microorganism-containing aerosols were higher at night than during the day. The techniques used in this study may be employed to establish microorganism-containing aerosol exposure during epidemiological investigations.

Procedure for the recovery of airborne human enteric viruses during spray irrigation of treated wastewater

Because of the relatively low number of indigenous enteric viruses recovered from secondary wastewater effluents, their presence in air (aerosols) as a result of wastewater spray irrigation requires extensive sampling. Methodology to allow the recovery of indigenous enteroviruses from aerosols generated at an operational wastewater irrigation site was tested under both laboratory and field conditions.

Coliform aerosols generated from the surface of dewatered sewage applied to a forest clearcut

Concentrations of airborne coliform bacteria as high as 1.5 X 10(4) m-3 were observed 8 cm above anaerobically digested sewage sludge applied to a forest clearcut. Dry conditions and high wind speeds tended to favor aerosol generation.