A study of air microbe levels in different areas of a hospital

Analysis of Mould Exposure of Immunosuppressed Patients at a German University Hospital

Moulds are ubiquitous components of outdoor and indoor air and local conditions, temperature, humidity and season can influence their concentration in the air. The impact of these factors on mould exposure in hospitals and the resulting risk of infection for low to moderately immunocompromised patients is unclear. In the present retrospective analysis for the years 2018 to 2022, the monthly determined mould contamination of the outdoor and indoor air at the University Hospital Frankfurt am Main is compared with the average air temperature and the relative humidity. Mould infections (Aspergillus spp., Mucorales) of low to moderately immunosuppressed patients of a haematological-oncological normal ward were determined clinically according to the criteria of the European Organisation for Research and Treatment of Cancer (EORTC, Brussels, Belgium) and of the National Reference Centre for Surveillance of Nosocomial Infections (NRC-NI, Berlin, Germany). The data revealed that in the summer months (May-October), increased mould contamination was detectable in the outdoor and indoor air compared to the winter months (November-April). The mould levels in the patient rooms followed the detection rates of the outdoor air. Two nosocomial Aspergillus infections, one nosocomial Mucorales (Rhizopus spp.) infection (according to both NRC-NI and EORTC criteria) and five Aspergillus spp. infections (according to EORTC criteria) occurred in 4299 treated patients (resulting in 41,500 patient days). In our study, the incidence density rate of contracting a nosocomial mould infection (n = 3) was approximately 0.07 per 1000 patient days and appears to be negligible.

Factors Affecting Gut Microbiota of Puppies from Birth to Weaning

The review described the most important factors affecting the development of the intestinal microbiota in puppies from birth to weaning. The health and well-being of the microbiome in puppies is influenced by the type of parturition, the maternal microbiota, and the diet of the mother, directly or indirectly. The isolation of bacteria in dogs from the placenta, fetal fluids, and fetuses suggests that colonization could occur before birth, although this is still a matter of debate. Accordingly, newborn puppies could harbor bacteria that could be of maternal origin and that could influence microbial colonization later in life. However, the long-term impacts on health and the clinical significance of this transfer is not yet clear and needs to be investigated. The same maternal bacteria were found in puppies that were born vaginally and in those delivered via cesarean section. Potentially, the relationship between the type of parturition and the colonization of the microbiome will influence the occurrence of diseases, since it can modulate the gut microbiome during early life. In addition, puppies' gut microbiota becomes progressively more similar to adult dogs at weaning, as a consequence of the transition from milk to solid food that works together with behavioral factors. A number of researches have investigated the effects of diet on the gut microbiota of dogs, revealing that dietary interference may affect the microbial composition and activity through the production of short-chain fatty acids and vitamins. These compounds play a fundamental role during the development of the fetus and the initial growth of the puppy. The composition of the diet fed during pregnancy to the bitches is also an important factor to consider for the health of newborns. As far as it is known, the effects of the type of parturition, the maternal microbiota, and the diet on the microbial colonization and the long-term health of the dogs deserve further studies. Definitely, longitudinal studies with a larger number of dogs will be required to assess a causal link between microbiome composition in puppies and diseases in adult dogs.

Interventional Effect of Nanosilver Paint on Fungal Load of Indoor Air in a Hospital Ward

Hospital ward environments contain various types of microorganisms, in which fungal agents are one of the main contaminants that may cause hospital-acquired infections. Regarding this, the aim of the present study was to evaluate the effect of nanosilver paint on reducing fungal contaminants of indoor air in an educational, research, and treatment center. Two rooms in the hematology ward were selected. One room was painted using usual paint (control room) and the other room was painted with paint containing nanosilver particles (experimental room). One hundred and twelve samples were collected using active (Anderson BioSampler) and passive (settle plate or open plate) air sampling techniques. The samples were incubated for 3–7 days at 35°C, and the positive fungal cultures were examined according to morphological and microscopic characteristics. Following active sampling, the mean and standard deviation of the number of colony-forming units (CFU/m³) of fungi colonies in the experimental and control rooms were 29.21 ± 17.99 and 22.50 ± 10.02 before intervention and 13.79 ± 6.20 and 31.07 ± 21.1 after intervention, respectively. Following passive sampling, the number of CFU/plate in the experimental and control rooms was 6 and 0 before and 1and 1 after intervention, respectively. The use of the nanosilver paint was effective in reducing air fungal contamination. Moreover, the active sampling method was more sensitive to measuring the concentration changes for fungal bioaerosols.

A systematic review and meta-analysis of indoor bioaerosols in hospitals: The influence of heating, ventilation, and air conditioning

OBJECTIVES

To evaluate (1) the relationship between heating, ventilation, and air conditioning (HVAC) systems and bioaerosol concentrations in hospital rooms, and (2) the effectiveness of laminar air flow (LAF) and high efficiency particulate air (HEPA) according to the indoor bioaerosol concentrations.

METHODS

Databases of Embase, PubMed, Cochrane Library, MEDLINE, and Web of Science were searched from 1st January 2000 to 31st December 2020. Two reviewers independently extracted data and assessed the quality of the studies. The samples obtained from different areas of hospitals were grouped and described statistically. Furthermore, the meta-analysis of LAF and HEPA were performed using random-effects models. The methodological quality of the studies included in the meta-analysis was assessed using the checklist recommended by the Agency for Healthcare Research and Quality.

RESULTS

The mean CFU/m3 of the conventional HVAC rooms and enhanced HVAC rooms was lower than that of rooms without HVAC systems. Furthermore, the use of the HEPA filter reduced bacteria by 113.13 (95% CI: -197.89, -28.38) CFU/m3 and fungi by 6.53 (95% CI: -10.50, -2.55) CFU/m3. Meanwhile, the indoor bacterial concentration of LAF systems decreased by 40.05 (95% CI: -55.52, -24.58) CFU/m3 compared to that of conventional HVAC systems.

CONCLUSIONS

The HVAC systems in hospitals can effectively remove bioaerosols. Further, the use of HEPA filters is an effective option for areas that are under-ventilated and require additional protection. However, other components of the LAF system other than the HEPA filter are not conducive to removing airborne bacteria and fungi.

LIMITATION OF STUDY

Although our study analysed the overall trend of indoor bioaerosols, the conclusions cannot be extrapolated to rare, hard-to-culture, and highly pathogenic species, as well as species complexes. These species require specific culture conditions or different sampling requirements. Investigating the effects of HVAC systems on these species via conventional culture counting methods is challenging and further analysis that includes combining molecular identification methods is necessary.

STRENGTH OF THE STUDY

Our study was the first meta-analysis to evaluate the effect of HVAC systems on indoor bioaerosols through microbial incubation count. Our study demonstrated that HVAC systems could effectively reduce overall bioaerosol concentrations to maintain better indoor air quality. Moreover, our study provided further evidence that other components of the LAF system other than the HEPA filter are not conducive to removing airborne bacteria and fungi.

PRACTICAL IMPLICATION

Our research showed that HEPA filters are more effective at removing bioaerosols in HVAC systems than the current LAF system. Therefore, instead of opting for the more costly LAF system, a filter with a higher filtration rate would be a better choice for indoor environments that require higher air quality; this is valuable for operating room construction and maintenance budget allocation.

Does Bacteria Colonization of Canine Newborns Start in the Uterus?

Simple Summary

A well-balanced microbial flora plays a fundamental role in puppies’ early development. Bacteria were thought to colonize newborns at birth, but some studies have challenged this hypothesis. A healthy fetus at term may already harbour bacteria and the uterus may also not be sterile. Time of initial microbiota development might be placed earlier in life. In this investigation we sampled uterus, amniotic fluid and meconium of healthy canine fetuses delivered through cesarean section (elective or emergency) and carried out bacteriological examinations. In contrast with the ‘sterile womb paradigm’, bacteria were isolated from all the sampled sites and materials, independently of the cesarean type. Further studies are necessary to confirm our results. We adopted traditional bacteria culture techniques, but molecular methods, which look for bacteria DNA, could also be performed to deepen the knowledge on this matter.

Abstract

The assumption that requires the uterus to be a sterile environment to sustain a successful pregnancy has been recently challenged in humans, and is still under debate. The aim of this study was to assess whether bacteria can be isolated from the pregnant uterus and from amniotic fluid and meconium of healthy canine fetuses at term, delivered through cesarean section. Fifteen dams of different breed, age and parity, undergoing either elective (n = 10) or emergency (n = 5) cesarean section after a healthy pregnancy, were included in the study. Swabs for bacterial culture were collected from the uterus, and from amniotic fluid and meconium. Bacteria were isolated from all the sampled sites and materials, irrespective of cesarean type. In most cases, different bacteria were isolated from the different sites. Acinetobacter spp., coagulase-negative Staphylococci and Bacillus spp. were frequently found while Pseudomonas aeruginosa, Micrococcus spp., Moraxella spp., Macrococcus spp., Glutamicibacter spp., Stenotrophomonas spp. and Psychrobacter spp. were only occasionally identified. Our data show that uterus and fetuses may not be sterile in healthy term canine pregnancies.

Fungi in the indoor air of critical hospital areas: a review

Invasive fungal infection is an important cause of mortality and morbidity in neonates, especially in low-birthweight neonates. The contribution of fungi in the indoor air to the incidence of mucocutaneous colonization and to the risk of invasive fungal infection in this population is uncertain. This review aimed to identify and to summarize the best available evidence on the fungal contamination in the indoor air of critical hospital areas with an emphasis on pediatric/neonatal ICUs. Publications from 2005 to 2019 were searched in the databases Scientific Electronic Library Online (SciELO), US National Library of Medicine National Institutes of Health Search (PubMed), and Latin American Caribbean Health Sciences (LILACS). Descriptors in Health Sciences (DeCS) were used. Research papers published in Portuguese, English, and Spanish were included. Twenty-nine papers on all continents except Australia were selected. The results showed that the air mycobiota contained several fungal species, notably Aspergillus, Penicillium, Cladosporium, Fusarium, and yeast (Candida) species. The selected papers point out the risks that fungi pose to neonates, who have immature immune system, and describe simultaneous external factors (air humidity, seasonality, air and people flow, use of particulate filters, and health professionals' hand hygiene) that contribute to indoor air contamination with fungi. Improving communication among health professionals is a great concern because this can prevent major health complications in neonates, especially in low-birthweight neonates. The results reinforced the need to monitor environmental fungi more frequently and efficiently in hospitals, especially in neonatal ICUs.

Indoor hospital air and the impact of ventilation on bioaerosols: a systematic review

Healthcare-acquired infections (HAIs) continue to persist in hospitals, despite the use of increasingly strict infection-control precautions. Opportunistic airborne transmission of potentially pathogenic bioaerosols may be one possible reason for this persistence. Therefore, this study aimed to systematically review the concentrations and compositions of indoor bioaerosols in different areas within hospitals and the effects of different ventilation systems. Electronic databases (Medline and Web of Science) were searched to identify articles of interest. The search was restricted to articles published from 2000 to 2017 in English. Aggregate data was used to examine the differences in mean colony forming units per cubic metre (cfu/m³) between different hospital areas and ventilation types. A total of 36 journal articles met the eligibility criteria. The mean total bioaerosol concentrations in the different areas of the hospitals were highest in the inpatient facilities (77 cfu/m³, 95% confidence interval (CI): 55-108) compared with the restricted (13cfu/m³, 95% CI: 10-15) and public areas (14 cfu/m³, 95% CI: 10-19). Hospital areas with natural ventilation had the highest total bioaerosol concentrations (201 cfu/m³, 95% CI: 135-300) compared with areas using conventional mechanical ventilation systems (20 cfu/m³, 95% CI: 16-24). Hospital areas using sophisticated mechanical ventilation systems (such as increased air changes per hour, directional flow and filtration systems) had the lowest total bioaerosol concentrations (9 cfu/m³, 95% CI: 7-13). Operating sophisticated mechanical ventilation systems in hospitals contributes to improved indoor air quality within hospitals, which assists in reducing the risk of airborne transmission of HAIs.

Concentration and type of bioaerosols before and after conventional disinfection and sterilization procedures inside hospital operating rooms

Operating rooms (ORs) in hospitals are sensitive wards because patients can get infections. This work aimed to characterize the type and concentration of bioaerosols in nine ORs of an educational hospital before and after sterilization and disinfection. During 2017, fungal samples were incubated at 25-28 °C for 3-7 days and bacterial samples at 37 °C for 24-48 h. The study results showed that the concentrations of fungi before cleaning procedures (for both of disinfection and sterilization) were limited from 4.83 to 18.40 CFU/m3 and after cleaning procedures ranged from 1.90 to 8.90 CFU/m3. In addition, the concentrations of bacteria before cleaning procedures were limited 14.65-167.40 CFU/m3 and after cleaning procedures ranged from 9.50 to 38.40 CFU/m3. The difference between the mean concentrations of airborne bioaerosols before and after sterilization was significantly different than the suggested value of 30 CFU/m3 (p ≤ 0.05). The bacterial concentration was higher than the recommended value (30 CFU/m3) in 41% of the ORs. The main fungal species identified in the indoor air of ORs (before vs. after sterilization) were A. fumigatus (25.6 vs. 18.3%), A. Niger (11.6 vs. 5.8%), Penicillium spp. (5.5 vs. 3.3%), Alternaria spp. (2.8 vs. 0.7%), Fusarium spp. (9.7 vs. 3.7%), Mucor spp. (15 vs. 12.7%), Cephalotrichum spp. (1.7 vs. 0.8%), A. Flavus (24.6 vs. 18.5%), Cladosporium spp. (2.6 vs. 0.8%), and Trichoderma spp. (0 vs. 0.9%). The growth of biological species even after sterilization and disinfection likely resulted from factors including poor ventilation, sweeping of OR floors, inadequate HVAC filtration, high humidity, and also lack of optimum management of infectious waste after surgery. Designing well-constructed ventilation and air-conditioning systems, replacing HEPA filters, implementing more stringent, frequent, and comprehensive disinfection procedures, and controlling temperature and humidity can help decrease bioaerosols in ORs.

Profiles of Environmental Mold: Indoor and Outdoor Air Sampling in a Hematology Hospital in Seoul, South Korea

Inhalation of fungal spores can cause various spectrums of fungal diseases in immunocompromised hosts. The aim of this study was to evaluate the concentrations and profiles of fungal species in air collected at different locations in hematology wards and outside of the hospital in Seoul St. Mary's Hospital over the course of a year. Air sampling was performed at four locations-outside the hospital (O), in the general ward (GW), in the lounge in the cleanroom (CR_L), and in the patients' room in the cleanroom (CR_R)-by using Andersen single-stage air sampler at every two weeks between May 2017 and May 2018. The results showed higher mean fungal density in summer, and the concentrations of fungi decreased as follows: O (954.8 colony-forming units, CFU/m³) > GW (4.2 CFU/m³) > CR_L (0.7 CFU/m³) > CR_R (0 CFU/m³). Aspergillus was most prevalent both inside (47%) and outside (62%) of the hospital. However, the outdoor fungal profile was more diverse than the indoor profile. Within the hospital, Penicillium was the second most dominant species. In conclusion, the outdoor fungal profile is diverse even in Seoul, a highly urbanized area in Korea. The distribution of indoor air fungi is significantly different from outdoor due to air quality systems. Heating, ventilation, and air conditioning (HVAC), as well as high-efficiency particulate air (HEPA)-filtered systems should be established to effectively reduce levels of indoor fungi.

Fungal burden exposure assessment in podiatry clinics from Ireland

Fungi are amongst the bioaerosols of most importance, as indicated by the growing interest in this field of research. The aim was to characterize the exposure to fungal burden in podiatry clinics using culture-based and molecular methods.

METHODS

Airborne fungi were collected using an impaction air sampler and surface samples were also performed. Fourteen air samples were collected for direct detection of fungal DNA from filamentous fungi and dermatophytes. Overall, 63.6 % of the evening samples and 46 % of the morning samples surpassed the threshold values (150 CFU/m³). Molecular detection, by real time PCR, of the target fungal species/strains (Aspergillus and Stachybotrys species) was negative for all samples collected. Trichophyton rubrum was detected by PCR analysis in one DNA sample collected on day six. Results suggest the use of both culture-based and molecular methodologies are desirable for a complete evaluation of fungal burden in this particular health care setting.

Antibiotic Resistance Patterns and Virulence Determinants of Different SCCmec and Pulsotypes of Staphylococcus Aureus Isolated from a Major Hospital in Ilam, Iran

Aims & Objectives:

The aim of this study is to evaluate genetic relatedness, antibiotic resistance pattern, and virulence characteristics of different types of S. aureus isolated from air, surfaces, staff, and patients in a Public hospital in Ilam.

Methods & Materials:

A total of 88 of 140 staphylococci identified as S. aureus by conventional and molecular methods were used in this study. Isolate samples were obtained from surfaces, staff, patients, and hospital indoor air. The sampling from staff and surfaces was done through using swab and air by standard pump. Antimicrobial susceptibility testing and presence different resistant and virulence determinants was assessed. Isolates were then typed by pulsed-field gel electrophoresis (PFGE) and SCCmec typing methods.

Results:

Out of 88isolates, 36 of them (40.9%) were MRSA. Among MRSA isolates, the range of resistance to antibiotic was 0% in vancomycin to 83.3% in gentamycin. The most prevalent resistant genes among gentamicin resistant S. aureus were acc (6')/aph (2”)Ia and aph(3”)IIIa. The most common erythromycin resistant gene was ermC. Surprisingly, SCCmec types I (30.5%), II (25%)were highly distributed. PFGE analysis showed 33 different pulsotypes.

Conclusion:

This study confirms that different isolates of MSSA and MRSA circulate in Ilam which differ in antimicrobial susceptibility, content of resistance, and virulence determinants.

A scoping review on bio-aerosols in healthcare and the dental environment

BACKGROUND

Bio-aerosols originate from different sources and their potentially pathogenic nature may form a hazard to healthcare workers and patients. So far no extensive review on existing evidence regarding bio-aerosols is available.

OBJECTIVES

This study aimed to review evidence on bio-aerosols in healthcare and the dental setting. The objectives were 1) What are the sources that generate bio-aerosols?; 2) What is the microbial load and composition of bio-aerosols and how were they measured?; and 3) What is the hazard posed by pathogenic micro-organisms transported via the aerosol route of transmission?

METHODS

Systematic scoping review design. Searched in PubMed and EMBASE from inception to 09-03-2016. References were screened and selected based on abstract and full text according to eligibility criteria. Full text articles were assessed for inclusion and summarized. The results are presented in three separate objectives and summarized for an overview of evidence.

RESULTS

The search yielded 5,823 studies, of which 62 were included. Dental hand pieces were found to generate aerosols in the dental settings. Another 30 sources from human activities, interventions and daily cleaning performances in the hospital also generate aerosols. Fifty-five bacterial species, 45 fungi genera and ten viruses were identified in a hospital setting and 16 bacterial and 23 fungal species in the dental environment. Patients with certain risk factors had a higher chance to acquire Legionella in hospitals. Such infections can lead to irreversible septic shock and death. Only a few studies found that bio-aerosol generating procedures resulted in transmission of infectious diseases or allergic reactions.

CONCLUSION

Bio-aerosols are generated via multiple sources such as different interventions, instruments and human activity. Bio-aerosols compositions reported are heterogeneous in their microbiological composition dependent on the setting and methodology. Legionella species were found to be a bio-aerosol dependent hazard to elderly and patients with respiratory complaints. But all aerosols can be can be hazardous to both patients and healthcare workers.

Assessment of multi-contaminant exposure in a cancer treatment center: a 2-year monitoring of molds, mycotoxins, endotoxins, and glucans in bioaerosols

Indoor air quality in health care facilities is a major public health concern, particularly for immunocompromised patients who may be exposed to microbiological contaminants such as molds, mycotoxins, endotoxins, and (1,3)-ß-D-glucans. Over 2 years, bioaerosols were collected on a monthly basis in a cancer treatment center (Centre F. Baclesse, Normandy, France), characterized from areas where there was no any particular air treatment. Results showed the complexity of mycoflora in bioaerosols with more than 100 fungal species identified. A list of major strains in hospital environments could be put forward due to the frequency, the concentration level, and/or the capacity to produce mycotoxins in vitro: Aspergillus fumigatus, Aspergillus melleus, Aspergillus niger, Aspergillus versicolor, Cladosporium herbarum, Purpureocillium lilacinum, and Penicillium brevicompactum. The mean levels of viable airborne fungal particles were less than 30.530 CFU per m³ of air and were correlated to the total number of 0.30 to 20 μm particles. Seasonal variations were observed with fungal particle peaks during the summer and autumn. Statistical analysis showed that airborne fungal particle levels depended on the relative humidity level which could be a useful indicator of fungal contamination. Finally, the exposure to airborne mycotoxins was very low (only 3 positive samples), and no mutagenic activity was found in bioaerosols. Nevertheless, some fungal strains such as Aspergillus versicolor or Penicillium brevicompactum showed toxigenic potential in vitro.

Construction and Analysis of Functional Networks in the Gut Microbiome of Type 2 Diabetes Patients

Although networks of microbial species have been widely used in the analysis of 16S rRNA sequencing data of a microbiome, the construction and analysis of a complete microbial gene network are in general problematic because of the large number of microbial genes in metagenomics studies. To overcome this limitation, we propose to map microbial genes to functional units, including KEGG orthologous groups and the evolutionary genealogy of genes: Non-supervised Orthologous Groups (eggNOG) orthologous groups, to enable the construction and analysis of a microbial functional network. We devised two statistical methods to infer pairwise relationships between microbial functional units based on a deep sequencing dataset of gut microbiome from type 2 diabetes (T2D) patients as well as healthy controls. Networks containing such functional units and their significant interactions were constructed subsequently. We conducted a variety of analyses of global properties, local properties, and functional modules in the resulting functional networks. Our data indicate that besides the observations consistent with the current knowledge, this study provides novel biological insights into the gut microbiome associated with T2D.

Occurrence of airborne vancomycin- and gentamicin-resistant bacteria in various hospital wards in Isfahan, Iran

BACKGROUND

Airborne transmission of pathogenic resistant bacteria is well recognized as an important route for the acquisition of a wide range of nosocomial infections in hospitals. The aim of this study was to determine the prevalence of airborne vancomycin and gentamicin (VM and GM) resistant bacteria in different wards of four educational hospitals.

MATERIALS AND METHODS

A total of 64 air samples were collected from operating theater (OT), Intensive Care Unit (ICU), surgery ward, and internal medicine ward of four educational hospitals in Isfahan, Iran. Airborne culturable bacteria were collected using all glass impingers. Samples were analyzed for the detection of VM- and GM-resistant bacteria.

RESULTS

The average level of bacteria ranged from 99 to 1079 CFU/m(3). The highest level of airborne bacteria was observed in hospital 4 (628 CFU/m(3)) and the highest average concentration of GM- and VM-resistant airborne bacteria were found in hospital 3 (22 CFU/m(3)). The mean concentration of airborne bacteria was the lowest in OT wards and GM- and VM-resistant airborne bacteria were not detected in this ward of hospitals. The highest prevalence of antibiotic-resistant airborne bacteria was observed in ICU ward. There was a statistically significant difference for the prevalence of VM-resistant bacteria between hospital wards (P = 0.012).

CONCLUSION

Our finding showed that the relatively high prevalence of VM- and GM-resistant airborne bacteria in ICUs could be a great concern from the point of view of patients' health. These results confirm the necessity of application of effective control measures which significantly decrease the exposure of high-risk patients to potentially airborne nosocomial infections.

Longitudinal Metagenomic Analysis of Hospital Air Identifies Clinically Relevant Microbes

We describe the sampling of sixty-three uncultured hospital air samples collected over a six-month period and analysis using shotgun metagenomic sequencing. Our primary goals were to determine the longitudinal metagenomic variability of this environment, identify and characterize genomes of potential pathogens and determine whether they are atypical to the hospital airborne metagenome. Air samples were collected from eight locations which included patient wards, the main lobby and outside. The resulting DNA libraries produced 972 million sequences representing 51 gigabases. Hierarchical clustering of samples by the most abundant 50 microbial orders generated three major nodes which primarily clustered by type of location. Because the indoor locations were longitudinally consistent, episodic relative increases in microbial genomic signatures related to the opportunistic pathogens Aspergillus, Penicillium and Stenotrophomonas were identified as outliers at specific locations. Further analysis of microbial reads specific for Stenotrophomonas maltophilia indicated homology to a sequenced multi-drug resistant clinical strain and we observed broad sequence coverage of resistance genes. We demonstrate that a shotgun metagenomic sequencing approach can be used to characterize the resistance determinants of pathogen genomes that are uncharacteristic for an otherwise consistent hospital air microbial metagenomic profile.

Hospital air: A potential route for transmission of infections caused by β-lactam-resistant bacteria

BACKGROUND

The emergence of bacterial resistance to β-lactam antibiotics seriously challenges the treatment of various nosocomial infections. This study was designed to investigate the presence of β-lactam-resistant bacteria (BLRB) in hospital air.

METHODS

A total of 64 air samples were collected in 4 hospital wards. Detection of airborne bacteria was carried out using culture plates with and without β-lactams. BLRB isolates were screened for the presence of 5 common β-lactamase-encoding genes. Sequence analysis of predominant BLRB was also performed.

RESULTS

The prevalence of BLRB ranged between 3% and 34%. Oxacillin-resistant bacteria had the highest prevalence, followed by ceftazidime- and cefazolin-resistant bacteria. The frequency of β-lactamase-encoding genes in isolated BLRB ranged between 0% and 47%, with the highest and lowest detection for OXA-23 and CTX-m-32, respectively. MecA had a relatively high frequency in surgery wards and operating theaters, whereas the frequency of blaTEM was higher in intensive care units and internal medicine wards. OXA-51 was detected in 4 wards. Acinetobacter spp, Acinetobacter baumannii, and Staphylococcus spp were the most predominant BLRB.

CONCLUSIONS

The results revealed that hospital air is a potential route of transmission of BLRB, such as Acinetobacter and Staphylococcus, 2 important causative agents of nosocomial infections. Therefore, improvement of control measures against the spreading of airborne bacteria in hospital environments is warranted.

A simple novel device for air sampling by electrokinetic capture

BACKGROUND

A variety of different sampling devices are currently available to acquire air samples for the study of the microbiome of the air. All have a degree of technical complexity that limits deployment. Here, we evaluate the use of a novel device, which has no technical complexity and is easily deployable.

RESULTS

An air-cleaning device powered by electrokinetic propulsion has been adapted to provide a universal method for collecting samples of the aerobiome. Plasma-induced charge in aerosol particles causes propulsion to and capture on a counter-electrode. The flow of ions creates net bulk airflow, with no moving parts. A device and electrode assembly have been re-designed from air-cleaning technology to provide an average air flow of 120 lpm. This compares favorably with current air sampling devices based on physical air pumping. Capture efficiency was determined by comparison with a 0.4 μm polycarbonate reference filter, using fluorescent latex particles in a controlled environment chamber. Performance was compared with the same reference filter method in field studies in three different environments. For 23 common fungal species by quantitative polymerase chain reaction (qPCR), there was 100 % sensitivity and apparent specificity of 87 %, with the reference filter taken as "gold standard." Further, bacterial analysis of 16S RNA by amplicon sequencing showed equivalent community structure captured by the electrokinetic device and the reference filter. Unlike other current air sampling methods, capture of particles is determined by charge and so is not controlled by particle mass. We analyzed particle sizes captured from air, without regard to specific analyte by atomic force microscopy: particles at least as low as 100 nM could be captured from ambient air.

CONCLUSIONS

This work introduces a very simple plug-and-play device that can sample air at a high-volume flow rate with no moving parts and collect particles down to the sub-micron range. The performance of the device is substantially equivalent to capture by pumping through a filter for microbiome analysis by quantitative PCR and amplicon sequencing.

Microbiological assessment of indoor air quality at different hospital sites

Poor hospital indoor air quality (IAQ) may lead to hospital-acquired infections, sick hospital syndrome and various occupational hazards. Air-control measures are crucial for reducing dissemination of airborne biological particles in hospitals. The objective of this study was to perform a survey of bioaerosol quality in different sites in a Portuguese Hospital, namely the operating theater (OT), the emergency service (ES) and the surgical ward (SW). Aerobic mesophilic bacterial counts (BCs) and fungal load (FL) were assessed by impaction directly onto tryptic soy agar and malt extract agar supplemented with antibiotic chloramphenicol (0.05%) plates, respectively using a MAS-100 air sampler. The ES revealed the highest airborne microbial concentrations (BC range 240-736 CFU/m(3) CFU/m(3); FL range 27-933 CFU/m(3)), exceeding, at several sampling sites, conformity criteria defined in national legislation [6]. Bacterial concentrations in the SW (BC range 99-495 CFU/m(3)) and the OT (BC range 12-170 CFU/m(3)) were under recommended criteria. While fungal levels were below 1 CFU/m(3) in the OT, in the SW (range 1-32 CFU/m(3)), there existed a site with fungal indoor concentrations higher than those detected outdoors. Airborne Gram-positive cocci were the most frequent phenotype (88%) detected from the measured bacterial population in all indoor environments. Staphylococcus (51%) and Micrococcus (37%) were dominant among the bacterial genera identified in the present study. Concerning indoor fungal characterization, the prevalent genera were Penicillium (41%) and Aspergillus (24%). Regular monitoring is essential for assessing air control efficiency and for detecting irregular introduction of airborne particles via clothing of visitors and medical staff or carriage by personal and medical materials. Furthermore, microbiological survey data should be used to clearly define specific air quality guidelines for controlled environments in hospital settings.

Characteristics of airborne micro-organisms in a neurological intensive care unit: Results from China

OBJECTIVE

To describe the characteristics of airborne micro-organisms in the environment in a Chinese neurological intensive care unit (NICU).

METHODS

This prospective study monitored the air environment in two wards (large and small) of an NICU in a tertiary hospital in China for 12 months, using an LWC-1 centrifugal air sampler. Airborne micro-organisms were identified using standard microbiology techniques.

RESULTS

The mean ± SD number of airborne bacteria was significantly higher in the large ward than in the small ward (200 ± 51 colony-forming units [CFU]/m(3) versus 110 ± 40 CFU/m(3), respectively). In the large ward only, the mean number of airborne bacteria in the autumn was significantly higher than in any of the other three seasons. A total of 279 airborne micro-organisms were identified (large ward: 195; small ward: 84). There was no significant difference in the type and distribution of airborne micro-organisms between the large and small wards. The majority of airborne micro-organisms were Gram-positive cocci in both wards.

CONCLUSION

These findings suggest that the number of airborne micro-organisms was related to the number of patients on the NICU ward.

Bioaerosol sampling for airborne bacteria in a small animal veterinary teaching hospital

BACKGROUND

Airborne microorganisms within the hospital environment can potentially cause infection in susceptible patients. The objectives of this study were to identify, quantify, and determine the nosocomial potential of common airborne microorganisms present within a small animal teaching hospital.

METHODS

Bioaerosol sampling was done initially in all 11 rooms and, subsequently, weekly samples were taken from selected rooms over a 9-week period. Samples were collected twice (morning and afternoon) at each site on each sampling day. The rooms were divided into two groups: Group 1, in which morning sampling was post-cleaning and afternoon sampling was during activity, and Group 2, in which morning sampling was pre-cleaning and afternoon sampling was post-cleaning. The total aerobic bacterial plate counts per m(3) and bacterial identification were done using standard microbiological methods.

RESULTS

A total of 14 bacterial genera were isolated with the most frequent being Micrococcus spp. followed by species of Corynebacterium, Bacillus, and Staphylococcus. There was a significant interaction between location and time for rooms in Group 1 (p=0.0028) but not in Group 2 (p>0.05). Microbial counts for rooms in Group 2 were significantly greater in the mornings than in the afternoon (p=0.0049). The microbial counts were also significantly different between some rooms (p=0.0333).

CONCLUSION

The detection of significantly higher airborne microbial loads in different rooms at different times of the day suggests that the probability of acquiring nosocomial infections is higher at these times and locations.

Assessment of the levels of airborne bacteria, Gram-negative bacteria, and fungi in hospital lobbies

Aims: We assessed the levels of airborne bacteria, Gram-negative bacteria (GNB), and fungi in six hospital lobbies, and investigated the environmental and hospital characteristics that affected the airborne microorganism levels. Methods: An Andersen single-stage sampler equipped with appropriate nutrition plate agar was used to collect the samples. The three types of microorganisms were repeatedly collected at a fixed location in each hospital (assumed to be representative of the entire hospital lobby) from 08:00 through 24:00, with a sampling time of less than 5 min. Temperature and relative humidity were simultaneously monitored. Results: Multiple regression analysis was used to identify the major factors affecting microorganism levels. The average levels of bacteria (7.2 × 10² CFU/m³), GNB (1.7 × 10 CFU/m³), and fungi (7.7 × 10 CFU/m³) indicated that all hospital lobbies were generally contaminated. Season was the only factor that significantly affected the levels of all microorganisms (p < 0.0001), where contamination was the highest during the summer, significantly higher than during the winter. Other significant factors varied by microorganism, as follows: airborne bacteria (number of people in the lobby, sampling time), GNB (scale of hospital), and fungi (humidity and air temperature). Conclusions: Hospital lobby air was generally contaminated with microorganisms, including bacteria, GNB, and fungi. Environmental factors that may significantly influence the airborne concentrations of these agents should be managed to minimize airborne levels.

Evaluation of microbiological air quality and of microclimate in university classrooms

The proliferation of air-diffused microorganisms inside public buildings such as schools, hospitals, and universities, is often indicated as a possible health risk. In this research, we have illustrated the results of an investigation realized to determine the health of the air in some university classrooms, both from a microbiological and a microclimatic viewpoint, during the normal didactic activity of direct lessons. The results obtained have been expressed by means of contamination indices, already used in previous works. Very little contamination was recorded in the different phases of air treatment, which underlines the efficiency of the system and of the maintenance protocols. The Global Index of Microbial Contamination (GIMC per cubic meter) showed a value greater than the mean during the heating period (290), while the highest values (95th percentile 1,138.45) were recorded in the period using air conditioning. The index of mesophilic bacterial contamination, though it did not show any significant differences in the various modes of air treatment, showed a mean value (1.34) and the 95th percentile value (4.14), which was greater in the air-conditioning phase. Finally, the mean value of the amplification index underlined a decrease in the microbial contamination in comparison to the outside, while showing situations of increased microbial amplification during the period of simple ventilation (95th percentile 4.27). The 95th percentile values found for GICM in the three sampling periods, however, permitted us to identify the value of GIMC per cubic meter equal to 1,000 as a guide to provide a means of self-monitoring the quality of the air inside the classrooms. From a microclimatic viewpoint, two periods of the year manifested discomfort situations: during the heating phase (winter) and during the simple ventilation phase (spring). The results obtained indicate, therefore, a need to intervene on the environmental parameters, not being able, in this particular case, to intervene on other aspects that influence the microclimate.

Distribution of bacterial contamination in a teaching hospital in Tehran - a special focus on Staphylococcus aureus

There are documents that confirm the cycle of bacterial transmission between patients, staff, and the inanimate environment. The environment may have more effect on intensive care units (ICUs), because the patients who require intensive care have unstable clinical conditions and are more sensitive to infections. The aim of this study was to determine the prevalence of bacteria in air and inanimate surface in the ICUs and to compare the microbial levels to standard levels.Air and inanimate surface in the four ICUs of a teaching hospital underwent weekly surveillance by means of air sampler and swabs for a period of six-month. Total bacterial counts were evaluated onto trypticase soy agar and mannitol salt agar (MSA).A total of 725 samples [air (168) and inanimate surfaces (557)] were collected. The total mean ± SD CFU/m3 of airborne bacteria in all of the ICUs were 115.93 ± 48.04. The most common bacteria in air of the ICUs were Gram-positive cocci (84.2%). The total mean ± SD airborne of Staphylococcus aureus was 12.10±8.11 CFU/m3. The highest levels of S. aureus contamination were found in ventilators and bed ledges. More suitable disinfection of hospital environments and monthly rotation in utilization of the various disinfectant agents are needed for the prevention of airborne and inanimate transmission of S. aureus.

Refurbishment works in a hospital during normal operation

BACKGROUND

Construction and renovation work in hospitals pose risks of fungal airborne infections for immunosuppressed patients. If possible, reconstruction work will be postponed to periods without patient treatment. However, in many situations urgent damage demands immediate refurbishment works before the transferring of patients to other wards or closure of wards is possible. Reported here are infection control related measures and implemented procedures after two incidents of water damage which occurred on a surgical ward and an intensive care unit at the University hospital of Essen.

METHODS

Between January and April 2009 and between September and October 2009, respectively, concentration of air-borne particles and number of viable fungi were measured at two surgical wards and one ICU. Preventive Infection Control Measures included erection of protective walls and HEPA filtration of air from the renovation area.

RESULTS

During the renovation work on the surgical ward concentrations of moulds and particles ≥5 µm were significantly higher on the left side of the renovation area than on the right side (p=0.036 and p<0.001). Concentrations of particles ≥1 µm and particles ≥5 µm on both sides of the renovation area were significantly increased when compared with the control ward on the same floor but not when compared with the control ward on the other floor. Particles of all size were significantly elevated on the ICU during the renovation work. Aspergillus fumigatus could neither be cultured of the air of cardiac surgery intensive care unit nor of the intermediate care unit (control ward). During renovation works there was no nosocomial mould infection of patients treated on the two wards.

CONCLUSION

Provided that the renovation area is tightly insulated from the areas of patient care on a ward, closure does not seem to be necessary during renovation works because variation of airborne fungi is similar to that of outdoor or control air. However a multidisciplinary team should be established. This team should perform risk assessment and determine necessary protective measures before starting any construction, renovation or maintenance work in health care settings.