Microbiological Air Quality in Heating, Ventilation and Air Conditioning Systems of Surgical and Intensive Care Areas: The Application of a Disinfection Procedure for Dehumidification Devices

Odour and indoor air quality hazards in railway cars: an Australian mixed methods case study

Purpose

This case study aimed to diagnose the cause(s) of a seasonal, and objectionable odour reported by travellers and drivers in the railway cars of Australian passenger trains. The research questions were to: (1) identify whether significant microbial colonisation was present within the air handling system of trains and causing the odours; to (2) identify other potential sources and; (3) remedial options for addressing the issue.

Methods

A mixed-methods, action research design was used adopted. Sections of the heating, ventilation, and air conditioning (HVAC) systems from odour-affected trains were swabbed for bacteria and fungi and examined for evidence of wear, fatigue and damage on-site and off-site. Insulation foam material extracted from the walls of affected trains was also subjected to a chemical assessment following exposure to varying humidity and temperature conditions in a climate simulator. This was accompanied by a qualitative sensory characterisation.

Results

Upon exposure to a variety of simulated temperature and humidity combinations to recreate the odour, volatile chemical compounds released from the insulation foam by water were identified as its likely cause. In addition, a range of potentially serious pathogenic and odour-causing microbes were cultured from the HVAC systems, although it is considered unlikely that bacterial colonies were the odour source.

Conclusion

The research has implications for the sanitising and maintenance policies for HVAC systems on public transport, especially when operating in humid environments. The sanitary imposition, especially in the wake of COVID-19 may be required to ensure the safety of the travelling public and drivers.

Assessment of Microbial Load in Regional Hospitals in Albania

Background Contaminated hospital indoor environments can expose patients to microorganisms and different infections. The aimed study was to assess the microbial load in hospital facilities inside Albania Regional Hospitals during the period 2017-2019. Methods A cross-sectional study was conducted during the period 2017-2019 for the assessment of microbial contamination in operating rooms, resuscitation, and delivery rooms in 12 regional hospitals in Albania. One thousand and three hundred microbiological specimens were collected from air and surfaces using 5% sheep blood agar (Oxoid, UK) and processed at IPH microbiology laboratory following the standard bacteriological procedures Data were analyzed using Statistical Software Package for Social Sciences (SPSS) version 23. Results Out of the total number of samples, 1148 (88.3%) were collected from surfaces and 152 (11.7%) were from the air. Bacterial growth was identified in 314 (24.2%) out of 1300 samples (95% CI 21.89–26.62). From the total site samples processed during the study period, bacterial growth showed 282 (89.8%) samples from surfaces and 32 (10.2%) air samples. There was found a significant association p-value =0.035. Regarding the sampling place collection, the largest number were collected in operating rooms (60.3%) followed by emergency rooms (28.2%), ICUs (7.7%), and maternity units (3.8%). Gram-negative isolates were predominant at 235 (74.8%), while the Gram-positive were at 60 (19.1%). E. coli was the most frequent bacterial isolate (50%) followed by Pseudomonas aeruginosa (23.6%), Staphylococcus aureus (19.1%), and Klebsiella pneumoniae (1.3%). Also, we found a fungal agent such as Aspergillus in 19 (6.1%) samples. The isolated bacteria's overall drug resistance profile revealed that 66.8% of gram-positive bacteria were resistant to two or more antimicrobial drugs tested. Conclusion This study revealed that the surface and air and air within different wards of the hospitals studied were contaminated with different types of bacteria. Bacterial loads on the surface and air exceeded normal limits. Additionally, the study pointed out high levels of antimicrobial resistance to the drugs commonly prescribed for isolates. Therefore, intervention strategies need to be strengthened to expand infection prevention practices in hospitals. Continuous monitoring and monitoring of in-hospital pathogen types and susceptibility patterns should be performed on a very regular basis.

Effectiveness of air purifiers in intensive care units: an interventional study

BACKGROUND

Effective design and operation of Intensive Care Unit (ICU) ventilation systems is important to prevent hospital-acquired infections. Air purifiers may contribute to that.

AIM

In this study we aimed at detecting the number and types of microorganisms present in the air and on the high touch surfaces in the ICU; evaluating the effectiveness of the air purifying device in reducing the microbial load and thus the rate of nosocomial infections in the ICU.

METHOD

This interventional study was conducted in two similar ICUs between December 2019 and May 2020. Novaerus brand air purifiers were located in the "intervention ICU" for two months. Routine cleaning procedures and HEPA filtered ventilation continued in "control ICU" as well as in the "Intervention ICU". After two months the units were moved to the other ICU for the next two months to reduce any possible bias in the results. Air and surface samples were evaluated.

FINDINGS

The evaluation of the change in the interventional ICU over time revealed a significantly lower colony concentration in the air and on surfaces on Day 60 compared to Day 1 (p_air<0.001 and p_surface<0.001). There was a significant positive correlation between the number of colonies detected and the rate of hospital-acquired infections in the interventional ICU (r:0.406, p:0.049) and in the control ICU (r:0.698, p:0.001).

CONCLUSION

Using air purifiers in addition to the hospital HVAC systems might be an effective way to reduce the microbial load in the air and surfaces and thus hospital-acquired infections.

Microbiological analysis of bacterial and fungal bioaerosols from burn hospital of Yazd (Iran) in 2019

INTRODUCTION

Bioaerosols play an important role in incidence of infections in indoor and outdoor air of hospitals. Microorganisms play a critical role in the health of human beings and they are found everywhere in the environment, including different wards of a hospital. So, quantitative and qualitative analysis of microorganisms is highly important in hospital air. The aim of this study was to evaluate the diversity and density of bacteria and fungi in the air of Shohadaye Mehrab Hospital in Yazd City, Iran.

MATERIALS AND METHODS

Sampling was performed using a single-stage pump (Quick Take30) at a flow rate of 28.3 l per minute for five minutes. As a result, 288 indoor and outdoor hospital air samples were collected. Numbers and types of bacterial and fungal colonies were identified using colony morphology, gram staining, and standard microbial tests. Chi-square test, PCA and linear mixed model were run by SPSS version 24.0 for data analysis.

RESULTS

The highest bacterial contaminations were found in the burns ward (294 CFU/m³), operating theater (147 CFU/m³), and emergency department (124 CFU/m³), respectively. Fungal contamination was higher in the derm ward (110 CFU/m³) than other sampling sites. The dominant genus of gram-positive bacteria was Staphylococcus epidermidis (n = 60, 62.5%) and the dominant genus of gram-negative bacteria was Citrobacter freundi (n = 11, 11.5%). The most fungal gens isolated from the hospital air samples were Penicillium (n = 73, 76%), Alternaria (n = 51, 53.1%), Aspergillus niger (n = 40, 41.7%), and Aspergillus flavus (n = 34, 35.4%), respectively.

CONCLUSION

Considering that the burn wounds represent a susceptible site for opportunistic microorganisms, even low concentration of fungi/bacteria in air can be considered as a risk factor that facilitates transmission of the infectious agents in the hospital. Therefore, control measures should be taken to reduce the infection hazard in health staff and patients. These measures include ensuring effective ventilation, cleaning and decontaminating surfaces and equipment, restricting the personnel and patient companions' movement across the wards.

Opportunist Coinfections by Nontuberculous Mycobacteria and Fungi in Immunocompromised Patients

Nontuberculous mycobacteria (NTM) and many fungal species (spp.) are commonly associated with opportunistic infections (OPIs) in immunocompromised individuals. Moreover, occurrence of concomitant infection by NTM (mainly spp. of Mycobacterium avium complex and Mycobacterium abscessus complex) and fungal spp. (mainly, Aspergillus fumigatus, Histoplasma capsulatum and Cryptococcus neoformans) is very challenging and is associated with poor patient prognosis. The most frequent clinical symptoms for coinfection and infection by single agents (fungi or NTM) are similar. For this reason, the accurate identification of the aetiological agent(s) is crucial to select the best treatment approach. Despite the significance of this topic it has not been sufficiently addressed in the literature. This review aims at summarizing case reports and studies on NTM and fungi coinfection during the last 20 years. In addition, it briefly characterizes OPIs and coinfection, describes key features of opportunistic pathogens (e.g., NTM and fungi) and human host predisposing conditions to OPIs onset and outcome. The review could interest a wide spectrum of audiences, including medical doctors and scientists, to improve awareness of these infections, leading to early identification in clinical settings and increasing research in the field. Improved diagnosis and availability of therapeutic options might contribute to improve the prognosis of patients' survival.

No-Touch Automated Room Disinfection after Autopsies of Exhumed Corpses

Autopsies of exhumed bodies pose a risk of infections with environmental bacteria or fungi, which may be life-threatening. Thus, it is important to use effective methods of disinfection in forensic pathology facilities. In this study, we investigated the effectiveness of no-touch automated disinfection (NTD) system after autopsies of exhumed bodies. Directly after 11 autopsies of exhumed bodies, we used an NTD system based on a peroxone vapor to disinfect the air and surfaces. We measured microbial burden in the air and on surfaces before and after NTD. The NTD system reduced the mean bacterial burden in the air from 171 colony forming units (CFU)/m³ to 3CFU/m³. The mean fungal burden in the air decreased from 221 CFU/m³ to 9CFU/m³. The mean all-surface microbial burden was 79 CFU/100 cm² after all autopsies, and it decreased to 2 CFU/100 cm² after NTD. In conclusion, the peroxone-based NTD system was effective for decontamination of the air and surfaces in a dissecting room after autopsies of exhumed bodies.

Heating, ventilation and air conditioning (HVAC) in intensive care unit

The aim of this review is to describe variation in standards and guidelines on ‘heating, ventilation and air-conditioning (HVAC)’ system maintenance in the intensive care units, across the world, which is required to maintain good ‘indoor air quality’ as an important non-pharmacological strategy in preventing hospital-acquired infections. An online search and review of standards and guidelines published by various societies including American Institute of Architects (AIA), American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE), Centers for Disease Control and Prevention (CDC), Department of Health Estates and Facilities Division, Health Technical Memorandum 2025 (HTM) and Healthcare Infection Control Practices Advisory Committee (HICPAC) along with various national expert committee consensus statements, regional and hospital-based protocols available in a public domain were retrieved. Selected publications and textbooks describing HVAC structural aspects were also reviewed, and we described the basic structural details of HVAC system as well as variations in the practised standards of HVAC system in the ICU, worldwide. In summary, there is a need of universal standards for HVAC system with a specific mention on the type of ICU, which should be incorporated into existing infection control practice guidelines.

A multimodality approach to decreasing ICU infections by hydrogen peroxide, silver cations, and compartmentalization

PURPOSE

Hospital-acquired infections in the Intensive Care Unit (ICU) account for an increase in morbidity and mortality leading to serious health complications. This study aims to determine the effect of a multimodality approach including disinfection and physical separation on the infections prevailing in ICU.

METHODS

The study employed prospective cross-over analysis to assess the 738 individuals (560 males and 178 females) at the ICU, Aseer Central Hospital, Saudi Arabia. The intervention programs were carried out for 3 years (2013-2015). It included the application of hydrogen peroxide and silver cations, physical separation, and compartmentalization of ICU. Acinetobacter spp., E. coli, and staphylococci were isolated, identified, and used to evaluate the efficacy of the intervention program.

RESULTS

The results provide endotracheal tube as the main specimen type (34.7%) followed by blood (29.1%), tracheal secretion (7.7%), wound (6%), urine (5.7%), throat swab (5.4%), sputum (3.7%), and other specimens (7.7%). It also showed the infection rate decreased from 14.3% to 4% in the last three months after continuous interventions (R² = 0.44). There was a decrease in the occurrence of bacteria after an intervention (p = 0.036).

CONCLUSION

The outcome of the study revealed that mist and separation measures offered a significant decrease in infections at the ICU as per the measurement of the most hazardous nosocomial pathogens.