Bacterial Surface Detachment during Nebulization with Contaminated Reusable Home Nebulizers.

Patients with chronic respiratory diseases use home nebulizers that are often contaminated with pathogenic microbes to deliver aerosolized medications. The conditions under which these microbes leave the surface as bioaerosols during nebulization are not well characterized. The objectives of this study were to (i) determine whether different pathogens detach and disperse from the nebulizer surface during aerosolization and (ii) measure the effects of relative humidity and drying times on bacterial surface detachment and aerosolization. Bacteria were cultured from bioaerosols after Pari LC Plus albuterol nebulization using two different sources, as follows: (i) previously used nebulizers donated by anonymous patients with cystic fibrosis (CF) and (ii) nebulizers inoculated with bacteria isolated from the lungs of CF patients. Fractionated bioaerosols were collected with a Next-Generation Impactor. For a subset of bacteria, surface adherence during rewetting was measured with fluorescence microscopy. Bacteria dispersed from the surface of used CF patient nebulizers during albuterol nebulization. Eighty percent (16/20) of clinical isolates inoculated on the nebulizer in the laboratory formed bioaerosols. Detachment from the plastic surface into the chamber solution predicted bioaerosol production. Increased relative humidity and decreased drying times after inoculation favored bacterial dispersion on aerosols during nebulized therapy. Pathogenic bacteria contaminating nebulizer surfaces detached from the surface as bioaerosols during nebulized therapies, especially under environmental conditions when contaminated nebulizers were dried or stored at high relative humidity. This finding emphasizes the need for appropriate nebulizer cleaning, disinfection, and complete drying during storage and informs environmental conditions that favor bacterial surface detachment during nebulization. IMPORTANCE Studies from around the world have demonstrated that many patients use contaminated nebulizers to deliver medication into their lungs. While it is known that using contaminated medications in a nebulizer can lead to a lung infection, whether bacteria on the surface of a contaminated nebulizer detach as bioaerosols capable of reaching the lung has not been studied. This work demonstrates that a subset of clinical bacteria enter solution from the surface during nebulization and are aerosolized. Environmental conditions of high relative humidity during storage favor dispersion from the surface. We also provide results of an in vitro assay conducted to monitor bacterial surface detachment during multiple cycles of rewetting that correlate with the results of nebulizer/bacterial surface interactions. These studies demonstrate for the first time that pathogenic bacteria on the nebulizer surface pose a risk of bacterial inhalation to patients who use contaminated nebulizers.

Susceptibility of the Mycobacterium abscessus complex to drying: Implications for nebulizer hygiene in patients with cystic fibrosis.

Background: Nebulizer hygiene and care is important in cystic fibrosis (CF) to minimize device contamination from bacteria, including nontuberculous mycobacteria (NTMs). Most nebulizer manufacturers recommend nebulizer drying, however there is little evidence to understand how nebulizer drying affects NTM survival. Methods: Mycobacterium abscessus subsp. massiliense (n = 2), M. abscessus subsp. bolletii (n = 2), and M. abscessus subsp. abscessus (n = 2) were evaluated for their ability to survive simulated drying conditions associated with routine nebulizer care. Bacterial inocula (circa. 107 colony-forming units) were added to plastic and allowed to dry to completeness for 24 h, employing passive and active drying. Results: NTM isolates of all subspecies could be recovered from all passive and active drying experiments, both in diluent and in sterile sputum, following drying (24 h). There was no combination of drying or physiology that supported NTM cell death, and there was no difference in observed survival with the three species of M. abscessus examined. Conclusion: This study indicates that drying, either passively or actively, for 24 h at room temperature, is unable to eradicate all M. abscessus organisms from dry plastic surfaces, even in the presence of residual sputum contamination. Whilst drying may be advantageous for nebulizer performance, it should not be regarded as an absolute control for the elimination of NTM organisms. With nebulizer hygiene, NTM organisms would be able to survive on a nebulizer following drying for 24 h, which has not undergone any formal disinfection protocol. Therefore, for NTM eradication from washed nebulizers, CF patients should therefore seek an effective alternative control to drying for NTM eradication, i.e., heat disinfection in baby bottle disinfectors. CF patients and health-care professionals should not rely solely on nebulizer drying to achieve NTM eradication.

[Evaluation of Hygiene in Dry Powder Steroid Drug Inhalers Used by Elderly Asthma Patients].

Dry powder inhalers (DPI) are frequently used by asthmatic patients, and the usage rate increases every year. The pharmacists at our hospital provided initial inhalation instructions on how the inhaler must be used but did not elaborate on the cleaning of the device. Therefore, the cleaning status of the inhaler is unknown, and there is a possibility of bacterial growth. This study investigated the cleaning status and hygiene of steroid drug inhalers used by elderly asthma patients. We administered a questionnaire to investigate the inhaler cleaning status after inhalation, and conducted a cross-sectional survey on hygiene using ATP measurement and bacterial culture examination. Considering the responses by 53 patients, it became clear that the ATP values of patients who answered "never cleaned" after inhalation were significantly higher than those who answered "cleaned every time". Moreover, some bacteria were detected in 62% of inhalers; 4 patients' inhalers contained bacteria other than normal oral microbial flora. In conclusion, because the inhalers used by elderly patients are in poor hygienic conditions, we must give cleaning instructions accordingly. We believe that it is necessary to give proper medical instructions along with instructions on the cleaning method with dry cloth.

Metagenomics Reveals a Core Macrolide Resistome Related to Microbiota in Chronic Respiratory Disease.

Rationale: Long-term antibiotic use for managing chronic respiratory disease is increasing; however, the role of the airway resistome and its relationship to host microbiomes remains unknown.Objectives: To evaluate airway resistomes and relate them to host and environmental microbiomes using ultradeep metagenomic shotgun sequencing.Methods: Airway specimens from 85 individuals with and without chronic respiratory disease (severe asthma, chronic obstructive pulmonary disease, and bronchiectasis) were subjected to metagenomic sequencing to an average depth exceeding 20 million reads. Respiratory and device-associated microbiomes were evaluated on the basis of taxonomical classification and functional annotation including the Comprehensive Antibiotic Resistance Database to determine airway resistomes. Co-occurrence networks of gene-microbe association were constructed to determine potential microbial sources of the airway resistome. Paired patient-inhaler metagenomes were compared (n = 31) to assess for the presence of airway-environment overlap in microbiomes and/or resistomes.Measurements and Main Results: Airway metagenomes exhibit taxonomic and metabolic diversity and distinct antimicrobial resistance patterns. A "core" airway resistome dominated by macrolide but with high prevalence of ß-lactam, fluoroquinolone, and tetracycline resistance genes exists and is independent of disease status or antibiotic exposure. Streptococcus and Actinomyces are key potential microbial reservoirs of macrolide resistance including the ermX, ermF, and msrD genes. Significant patient-inhaler overlap in airway microbiomes and their resistomes is identified where the latter may be a proxy for airway microbiome assessment in chronic respiratory disease.Conclusions: Metagenomic analysis of the airway reveals a core macrolide resistome harbored by the host microbiome.

Microbial contamination of home nebulizers in children with cystic fibrosis and clinical implication on the number of pulmonary exacerbations.

BACKGROUND: Early detection of pulmonary contamination in children with cystic fibrosis (CF) is essential since these children are vulnerable to Pseudomonas aeruginosa (P. aeruginosa) colonization. In Iran, home nebulization of antibiotics is a widespread practice in treatment for patients with CF and, to the best our knowledge, no bacteriological surveys have been conducted till date in this regard. METHOD: This observational, cross sectional study was conducted on 61 children with CF at Mofid Children's Hospital, Tehran, from September 2017 to march 2018. The swab sampling was performed from 61 home nebulizers used by children diagnosed with CF. Contemporaneous sputum sample or deep nasopharyngeal swab was taken from each patient for bacterial and fungal testing. Medical records of the patients were reviewed and the number of exacerbations were recorded over the last 12 months prior to the study enrollment. RESULTS: The results of study showed that, 43 (70.5%) nebulizers were contaminated; 31 (50.8%) mouthpieces, 21 (34.4%) reservoirs, and 11 (18%) connecting tubes. The most common organism to be isolated was P. aeruginosa and was recovered from 19 (31%) nebulizers, 16 of them belonged to patients chronically colonized with P. aeruginosa. The remaining three had at least one positive sputum culture for P. aeruginosa in the past 1 year before the study. There was a significant increase in the number of CF exacerbations with an average number of exacerbation being 1.5 ± 1(SD) over last 12 months in children who had pathogenic organisms recovered from their home nebulizers compared with 0.4 ± 0.7(SD) exacerbations per year in whom non-pathogenic organisms were isolated from their nebulizers (P < 0.001). CONCLUSION: The majority of domiciliary nebulizers used by children with CF were contaminated with microorganisms indicating that the nebulizers may serve as potential reservoirs of pathogens for the patients' lung. Perpetuating colonization is a possible concern in the ones recently colonized with P. aeruginosa and, therefore, decontamination of nebulizer requires more attention to prevent ongoing infection. The negative impact of contamination of nebulizer on CF exacerbation requires serious attention and further investigations.

Microbiological contamination of nebulizers used by cystic fibrosis patients: an underestimated problem.

OBJECTIVE: Home nebulizers are routinely used in the treatment of patients with cystic fibrosis (CF). This study aims to evaluate the contamination of nebulizers used for CF patients, that are chronically colonized by Pseudomonas aeruginosa, and the association of nebulizer contamination with cleaning, decontamination and drying practices. METHODS: A cross-sectional, observational, multicenter study was conducted in seven CF reference centers in Brazil to obtain data from medical records, structured interviews with patients/caregivers were performed, and nebulizer's parts (interface and cup) were collected for microbiological culture. RESULTS: overall, 77 CF patients were included. The frequency of nebulizer contamination was 71.6%. Candida spp. (52.9%), Stenotrophomonas maltophilia (11.9%), non-mucoid P. aeruginosa (4.8%), Staphylococcus aureus (4.8%) and Burkholderia cepacia complex (2.4%) were the most common isolated pathogens. The frequency of nebulizers' hygiene was 97.4%, and 70.3% of patients reported cleaning, disinfection and drying the nebulizers. The use of tap water in cleaning method and outdoor drying of the parts significantly increased (9.10 times) the chance of nebulizers' contamination. CONCLUSION: Despite the high frequency hygiene of the nebulizers reported, the cleaning and disinfection methods used were often inadequate. A significant proportion of nebulizers was contaminated with potentially pathogenic microorganisms for CF patients. These findings support the need to include patients/caregivers in educational programs and / or new strategies for delivering inhaled antibiotics.

Nebulizer cleaning and disinfection practices in families with cystic fibrosis: The relationship between attitudes, practice and microbe colonization.

BACKGROUND: The daily burden of health maintenance for children and families with cystic fibrosis (CF) is immense with respect to time and complexity of care. Infection control practices, specifically nebulizer cleaning and disinfection, are a recommended component of home health care for CF families due to colonization of home respiratory equipment with lung pathogens. To better inform education interventions at our center, we were interested in studying how families' views on infection prevention and awareness of CF Foundation infection prevention and control (IP&C) guidelines correlate with actual home nebulizer care and the presence of microorganisms on their nebulizers. METHODS: Twenty families who have children with CF were surveyed to better understand attitudes toward infection prevention, awareness of CFF IP&C guidelines and nebulizer cleaning and disinfection practices in the home. Their nebulizers were also cultured for microbes to correlate recovery with infection control behaviors. RESULTS: A subset of families recognizes the importance of germ avoidance but do not recognize nebulizer cleaning and disinfection as very important for infection control practices. Decreased frequency of disinfection, but not cleaning, was correlated with the recovery of organisms on the nebulizers. CONCLUSIONS: The study questionnaire results identify a gap between recognizing the importance of infection prevention and consistently implementing CFF IP&C guidelines in the home. This demonstrates the need at our center for new educational interventions to promote cleaning and disinfection of home nebulizers after each use as recommended by the CFF.

Cystic fibrosis in the modern therapeutic era: Give the shower a thought!

Fifty-two meshes of e-flow rapid® were characterized for tobramycin delivery with a laser diffractometer after 6 months of home use by cystic fibrosis patients treated with various nebulized drugs. Three meshes were out of order and 30 considered to be defective for tobramycin delivery. The use of the specific mesh cleaning shower system permitted 14 defective meshes to be in the expected range of nebulized volume.

Contaminación microbiana de dispositivos de nebulización de anfotericina B liposomal en pacientes trasplantados pulmonares / Microbial contamination of liposomal amphotericin B nebuliser devices in lung transplant patients

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Repeated hot water and steam disinfection of Pari LC Plus® nebulizers alter nebulizer output.

Currently, cystic fibrosis patients require daily nebulized treatments to achieve optimal lung health. Growth of pathogenic bacteria in patient nebulizers is well known, and disinfection guidelines have been established. In this short communication, we sought to discover what effect, if any, repeated nebulization/disinfection cycles had on nebulizer output. We nebulized saline repeatedly after exposure to boiling water, steam, and alcohol disinfection methods. While alcohol disinfection did not affect nebulizer output, boiling water and steam significantly decreased nebulizer output from baseline, 74.1 ±â€¯5.9% (p = 0.022) and steam 63.6 ±â€¯6.5% (p = 0.0048) after 60 cycles respectively. This decrease in nebulizer output could significantly increase the duration of nebulizer treatment time and negatively impact the burden of care on patients with cystic fibrosis.

Microbiological contamination in high and low flow oxygen humidifiers: A systematic review. / Contaminación microbiológica en humidificadores de sistemas de oxigenoterapia de alto y bajo flujo: una revisión sistemática.

AIM: To determine the risk of microbiological contamination with hospital use high- and low-flow bubbling humidifiers. METHODS: A systematic literature review was carried out in 6 databases. Observational or experimental studies published between 1990 and 2016 were selected, written in English or Spanish, and in which microbiological contamination with hospital use high- and low-flow bubbling humidifiers was investigated. RESULTS: A total of 12 articles were included: 4 analyzed the water from reusable humidifiers, 4 analyzed the water from prefilled system humidifiers, and the rest compared samples from both models. Microbial contamination was observed in all studies in which reusable humidifiers were evaluated, usually involving common bacteria from the skin flora, while potential pathogenic species were notified in 2 studies. No microbial contamination was isolated from reusable humidifiers, regardless of whether they had been consecutively used over time by a single patient or by several patients. CONCLUSION: On one hand, there seems to be a low risk of contamination during the first weeks of use of prefilled humidifiers, which allows multiple use in different patients, without a risk of cross-contamination. On the other hand, it should be underscored that handling reusable humidifiers without correct aseptic measures can increase the risk of contamination; replacing reusable humidifiers with prefilled models therefore could be the safest option.

Microbiological contamination of nebulizers used by cystic fibrosis patients: an underestimated problem / Contaminação microbiológica de nebulizadores usados por pacientes com fibrose cística: um problema subestimado

ABSTRACT Objective: Home nebulizers are routinely used in the treatment of patients with cystic fibrosis (CF). This study aims to evaluate the contamination of nebulizers used for CF patients, that are chronically colonized by Pseudomonas aeruginosa, and the association of nebulizer contamination with cleaning, decontamination and drying practices. Methods: A cross-sectional, observational, multicenter study was conducted in seven CF reference centers in Brazil to obtain data from medical records, structured interviews with patients/caregivers were performed, and nebulizer's parts (interface and cup) were collected for microbiological culture. Results: overall, 77 CF patients were included. The frequency of nebulizer contamination was 71.6%. Candida spp. (52.9%), Stenotrophomonas maltophilia (11.9%), non-mucoid P. aeruginosa (4.8%), Staphylococcus aureus (4.8%) and Burkholderia cepacia complex (2.4%) were the most common isolated pathogens. The frequency of nebulizers' hygiene was 97.4%, and 70.3% of patients reported cleaning, disinfection and drying the nebulizers. The use of tap water in cleaning method and outdoor drying of the parts significantly increased (9.10 times) the chance of nebulizers' contamination. Conclusion: Despite the high frequency hygiene of the nebulizers reported, the cleaning and disinfection methods used were often inadequate. A significant proportion of nebulizers was contaminated with potentially pathogenic microorganisms for CF patients. These findings support the need to include patients/caregivers in educational programs and / or new strategies for delivering inhaled antibiotics.

RESUMO Objetivo: Nebulizadores caseiros são usados rotineiramente no tratamento de pacientes com fibrose cística (FC). Este estudo objetiva avaliar a contaminação de nebulizadores utilizados por pacientes de FC que estão cronicamente colonizados por Pseudomonas aeruginosa e a associação da contaminação do nebulizador com a higienização, esterilização e método de secagem. Métodos: Um estudo transversal, observacional, multicêntrico foi conduzido em sete centros de referência de FC no Brasil para obter dados de registros médicos; foram feitas entrevistas estruturadas com os pacientes/cuidadores e partes de nebulizadores (máscara e copo) foram coletados para cultura microbiológica. Resultados: No geral, 77 pacientes com FC foram incluídos. A frequência da contaminação do nebulizador foi de 71,6%. Candida spp. (52,9%), Stenotrophomonas maltophilia (11,9%), P. aeruginosa não mucoide (4,8%), Staphylococcus aureus (4,8%) e complexo Burkholderia cepacia (2.4%) foram os patógenos isolados mais comuns. A frequência de higienização dos nebulizadores foi de 97,4%, e 70,3% dos pacientes relata higienização, esterilização e secagem dos aparelhos. A lavagem com água da torneira e secagem das partes no tempo, em espaço aberto, aumentou significativamente (9 a 10 vezes) a chance de contaminação dos nebulizadores. Conclusões: Apesar dos relatos de frequente higienização dos nebulizadores, os métodos de limpeza e esterilização usados eram inadequados. Uma proporção significativa de nebulizadores foi contaminada com microrganismos potencialmente patogênicos para pacientes com FC. Estes resultados apoiam a necessidade de inclusão dos pacientes/cuidadores em programas educacionais e/ou novas estratégias para fornecimento de antibióticos inalatórios.

Differential gene expression in Escherichia coli during aerosolization from liquid suspension.

Comparative transcriptome analysis was used to determine the differentially expressed genes in Escherichia coli during aerosolization from liquid suspension. Isogenic mutant studies were then used to examine the potential part played by some of these genes in bacterial survival in the air. Bioaerosols were sampled after 3 min of nebulization, which aerosolized the bacteria from the liquid suspension to an aerosol chamber (A0), and after further 30 min of airborne suspension in the chamber (A30). Bacteria at A0 showed 65 differentially expressed genes (30 downregulated and 35 upregulated) as compared to the original bacteria in the nebulizer. Droplet evaporation models predicted a drop in temperature in the bioaerosols, which coincides with the change in the expression of cold shock protein genes-cspB and cspG in the bacteria. The most notable group of differentially expressed genes was sorbitol transport and metabolism genes (srlABDEMR). Other genes associated with osmotic stress, nutrient limitation, DNA damage, and other stresses were differentially expressed in the bacteria at A0. After further airborne suspension, one gene (ypfM, which encodes a hypothetical protein with unknown function) was downregulated in the bacteria at A30 as compared to those at A0. Finally, isogenic mutants with either the dps or srlA gene deleted (both genes were upregulated at A0) had lower survival than the parental strain, which is a sign of their potential ability to protect the bacteria in the air.

Preferential aerosolization of bacteria in bioaerosols generated in vitro.

AIMS: Little is known about how bacteria are aerosolized in terms of whether some bacteria will be found in the air more readily than others that are present in the source. This report describes in vitro experiments to compare aerosolization rates (also known as preferential aerosolization) of Gram-positive and Gram-negative bacteria as well as rod- and coccus-shaped bacteria, using two nebulization conditions. METHODS AND RESULTS: A consortium of five bacterial species was aerosolized in a homemade chamber. Aerosols generated with a commercial nebulizer and a homemade bubble-burst aerosol generator were compared. Data suggest that Pseudomonas aeruginosa was preferentially aerosolized in comparison to Moraxella catarrhalis, Lactobacillus paracasei, Staphylococcus aureus and Streptococcus suis, independently of the method of aerosolization. Bacterial integrity of Strep. suis was more preserved compared to other bacteria studied as revealed with PMA-qPCR. CONCLUSION: We reported the design of an aerosol chamber and bubble-burst generator for the in vitro study of preferential aerosolization. In our setting, preferential aerosolization was influenced by bacterial properties instead of aerosolization mechanism. SIGNIFICANCE AND IMPACT OF THE STUDY: These findings could have important implications for predicting the composition of bioaerosols in various locations such as wastewater treatment plants, agricultural settings and health care settings.

Cleaning and infection control of airway clearance devices used by CF patients.

Respiratory treatment for cystic fibrosis (CF) patients includes use of respiratory devices. Contamination of airway clearance devices has not been adequately explored. We aimed to determine whether airway clearance devices are contaminated after use and whether cleaning guidelines for nebulizers are as effective for airway clearance devices. Patients brought their airway clearance devices to the clinic. Swabs from the devices were taken before and after cleaning and were cultured for bacterial counts. Total colony-forming units (CFU) was determined, and predominant colonies were identified using Matrix-Assisted Laser Desorption Ionization Time-of-Flight Mass Spectrometry technology. Thirty devices were collected from 23 patients. Most of the devices (28/30) were contaminated when brought to the clinic. Complete bacterial eradication was achieved in 15 (50%) samples and partial eradication in 9 (30%). The cleaning was totally ineffective in four samples. Median CFU decreased significantly from 1250 (IQR 25-75% 175-10.000) to 0 (IQR 25-75% 0-700) before and after cleaning ( p < 0.0001). The predominant organisms were identified in five samples only, and there was no concordance with sputum culture results. Airway clearance devices are contaminated after use, and appropriate cleaning can reduce contamination. The effect on disease progression in CF patients is unclear. There is a need for infection prevention and control guidelines for the growing number of respiratory devices.