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   Abstract
  Introduction
  Subjects and Methods
  Results
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ORIGINAL ARTICLE
Year : 2021  |  Volume : 25  |  Issue : 2  |  Page : 78-83
 

Assessment of bacterial pathogens and their antibiotic resistance in the air of different wards of selected teaching hospitals in Tehran


1 MSc in Occupational Health Engineering, School of Public Health and Safety, Shahid Beheshti University of Medical Sciences, Tehran, Iran
2 Department of Microbiology, Faculty of Biological Sciences and Technology, Shahid Beheshti University, Tehran, Iran
3 Ph.D. Candidate in Occupational Health Engineering, School of Public Health and Safety, Shahid Beheshti University of Medical Sciences, Tehran, Iran
4 Depatment of Environmental Health Engineering, School of Public Health and Safety, Shahid Beheshti University of Medical Sciences, Tehran, Iran
5 Department of Epidemiology, School of Public Health and Safety, Shahid Beheshti University of Medical Sciences, Tehran, Iran
6 Associate Professor in Occupational Health Engineering; Department of Environmental and Occupational Hazards Control Research Center, School of Public Health and Safety, Shahid Beheshti University of Medical Sciences, Tehran, Iran

Date of Submission28-Sep-2019
Date of Decision25-Jul-2020
Date of Acceptance25-Sep-2020
Date of Web Publication9-Jul-2021

Correspondence Address:
Dr. Rezvan Zendehdel
Environmental and Occupational Hazards Control Research Center, School of Public Health and Safety, Shahid Beheshti University of Medical Sciences, Tehran
Iran
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/ijoem.IJOEM_234_19

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  Abstract 


Context: Exposure to bio-aerosols in a variety of environments has been of great interest due to the health effects on humans. Hospitals can be the reservoir of these biological agents because of the presence of infectious patients; which can lead to hospital infections and various occupational hazards. In this way, we assessed bacterial contamination in two teaching hospitals in Tehran. Aims: Our purpose in this study assessment of bacterial pathogens and their antibiotic resistance in the air of different wards of selected teaching hospitals in Tehran. Settings and Design: In this study, sampling was done according to NIOSH 0800. Methods and Material: This descriptive study was carried out in the different sections of two hospitals in Tehran. A total of 180 air samples were evaluated according to NIOSH 0800. In each section sampling was performed on the culture media in three stations including primary room, end room, and nursing position then the number of colonies counted. The zone of inhibition was measured in antibiotic disks to determine antibiotic resistance of samples. Statistical Analysis Used: Data analysis was performed using SPSS version 21. Initially, the data were normalized using the Kolmogorov–Smirnov test. The difference between the two hospitals was achieved with Mann–Whitney U test for un-normal distribution data. Results: Bacterial contamination in hospital 2 was significantly higher than the hospital 1(P < 0.001). The median number of colonies in hospital 1 was 129.87 (87.46–268.97) CFU/m3 and 297.97 (217.66–431.85) CFU/m3 for hospital 2. Bacterial contamination in the all of stations in hospital 2 and 87% of samples in hospital 1 was higher than the acceptable range of ACGIH (75 CFU/m3). Conclusions: High bacterial contamination may be related to a lack of hygiene management and poor ventilation system. It seems effective infection control processes, appropriate ventilation systems and supervision systems should be improved.


Keywords: Antibiotic resistance, bacterial, bio-aerosol, hospital


How to cite this article:
Montazer M, Soleimani N, Vahabi M, Abtahi M, Etemad K, Zendehdel R. Assessment of bacterial pathogens and their antibiotic resistance in the air of different wards of selected teaching hospitals in Tehran. Indian J Occup Environ Med 2021;25:78-83

How to cite this URL:
Montazer M, Soleimani N, Vahabi M, Abtahi M, Etemad K, Zendehdel R. Assessment of bacterial pathogens and their antibiotic resistance in the air of different wards of selected teaching hospitals in Tehran. Indian J Occup Environ Med [serial online] 2021 [cited 2021 Jul 27];25:78-83. Available from: https://www.ijoem.com/text.asp?2021/25/2/78/321068





  Introduction Top


Exposure to bio-aerosols both in occupational and environmental settings has attracted much attention, due to its effects on human health.[1] Infectious patients in hospitals can be the sources of these bio-aerosols.[2] In hospitals, poor indoor air quality due to the dense presence of airborne bacteria increases the concern about the health of staff and patients,[3] especially those with highly susceptible to the adverse effects of microbes.[4] These biological agents can lead to hospital infections and various occupational hazards.[5] Annually 2 to 4 million people become infected with hospital infections.[6] Controlling airborne pathogens in hospitals is important not only for patient safety but also for hospital staff.[7] Bacterial exposure of hospital staff has always raised concerns about the risk of occupational infections for medical staff. Baba et al. reported the transmission risk of Streptococcus pyogenes from patients with fatal pneumonia in the nurses.[8]

Bacteria is one of the largest types of bio-aerosols[9] present in different sections of the hospital.[2] Because of their small size, they have a long time to stay in the atmosphere and can be transported over long distances compared with big particles.[10] some bacteria, particularly gram-positive bacteria such as S. pneumoniae and S. aureus survive in dust particles.[7] The bacteria in the air of hospitals mainly include  Escherichia More Details coli, Staphylococcus species, Enterococcus species, Enterobacter spp., Pseudomonas species, Micrococcus, Corynebacterium fossils, and Mycobacterium tuberculosis.[11],[12],[13],[14] The main factors affecting the level of microorganisms are dirtiness of the hospital, the activity of individuals, and the efficiency of ventilation in hospitals.[15]

Exposure to these biological agents is associated with a wide range of major public health effects.[16] Exposure of building residents to certain microorganisms also causes allergic reactions, stimulus responses, respiratory diseases, and other health effects.[17] Among these, infectious and respiratory diseases are more common.[18]

Infectious diseases are the second serious cause of death worldwide.[19] Hospital infections have imposed heavy costs on the health system of countries.[20] Bacteria are one of the agents that cause hospital infections, become easily resistant to many common antibiotics.[21] An increase in infections with antibiotic-resistant microorganisms has become one of the serious problems in world health care systems.[19]

Many studies have emphasized that hospitals as a source of emission and transmission of acquired infections and bio-aerosols are at high risk. Therefore, information on the prevalence of bacteria in hospitals is important.[16] Bio-aerosols monitoring in hospitals provides information on the epidemiology of infectious diseases, research into the emission of airborne microorganisms, biohazard monitoring, and use in quality control.[22] Because of subjective sensitivity to biological agents, the concentration of airborne bio-aerosols should be reduced to the minimum and monitored regularly.[23] This study aimed to evaluate the level of airborne bacteria in different sections of two hospitals and analyzed the antibiotic resistance of existing bacteria.


  Subjects and Methods Top


This descriptive study was carried out for two selected teaching hospitals in Tehran with a top grade of health rank. According to other studies[24],[25] minimum (p1) and maximum (p2), bacterial contamination in the hospitals was considered 0.2 and 0.6, respectively. By considering 0.05 for α and 0.2 for β, the sample size was calculated using the following formula:



Based on the number of beds in the two hospitals, 45 stations were selected for hospital number 1 (No. 1) and 15 places for hospital No. 2. In each section, sampling was performed in three stations including the primary room, end room, and nursing location. The list of studied sections is shown in [Table 1].
Table 1: Studied section in two teaching hospital

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Sampling was performed according to NIOSH 0800 with a rate of 28.3 L/min during 5 min on culture media. Three samples with three different media were prepared in each station. Therefore, a total of 180 air samples were assessed in 60 stations of two hospitals. Nutrient agar was used for the detection of total bacteria contamination, mannitol salt agar was used to examine the gram-positive bacteria and MacConkey agar was used to determine gram-negative bacteria. For each station, one sample was considered as a blank sample containing nutrient agar media. Samples were evaluated by a bacterial sampler (Casella London) at a height of 1.5 m from the ground and 1 m from walls and obstacles. Before sampling, the bacterial sampler was sterilized by ultraviolet light and 70% alcohol. Samples were incubated at 37 °C for 18 h and then the number of colonies in nutrient agar was reported based on formula 1 as an airborne level of exposure.[26]



C = Number of colonies per colonial unit per cubic meter of air

T = Total number of colonies counted in the culture media

T = time (min)

F = flow (L/min)

Air samples on the mannitol salt agar were surveyed by catalase test (based on NCCLS guideline) for Staphylococcus aureus assessment. Gram-negative bacteria in MacConkey agar were detected by protocols of diagnosis gallery tests (NCCLS1). All of the sampled bacteria were incubated in Muller Hinton agar media and resistance of bacteria was evaluated by antibiotic disks of amikacin (AN), oxacillin (OX), ceftazidime (CAZ), imipenem (IPM), and sulfamethoxazole (SXT). The zone of inhibition for each antibiotic disk was measured with an accuracy of millimeters. Finally, bacterial resistance is classified according to the CLSI standard as susceptible, intermediate, and resistant.

Data analysis was performed using SPSS version 21. Initially, the data were normalized using the Kolmogorov–Smirnov test. The difference between the two hospitals was achieved with student t-test in normal data and Mann–Whitney U test for un-normal distribution data. Pearson correlation coefficient test was used to check the relationship between the level of bacteria with temperature and pressure parameters.

Ethical statement

This study has been approved in the 6th meeting of the Organizing Committee of Ethics in Health Research and Neurosciences 2016/09/172 with the code of Ethics IR.SBMU.PHNS.REC.1395.39.


  Results Top


Two hospitals with the top grade of health rank were studied. [Table 2] characterizes the specification of studied hospitals.
Table 2: Hospital characterization

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The median level of colonies in the wards of hospital 1 was 129.87 (87.46–268.97) CFU/m3 and 297.97 (217.66–431.85) CFU/m3 for hospital 2. [Table 3] shows the number of colonies in different wards of hospital 1 and 2. The results show bacterial contamination in the cardiology inpatient ward of hospital 1 has higher than other sections while bacterial colonies in general surgery are the lowest level. In Hospital No. 2, the air of the operating room had the highest bacterial contamination, and ICU had the lowest colony number.
Table 3: Bacterial contamination in hospital 1 and 2

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Percentage of ward with bacterial contamination exceeding ACGIH/WHO standards in both the hospitals is shown in [Table 4].
Table 4: Percentage of ward with bacterial contamination in hospitals

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Bacterial contamination in the nursing station is not significantly different from inpatient rooms [Table 5].
Table 5: Bacterial contamination in the nursing station and inpatient rooms

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The results of Mann–Whitney U test show colony number in hospital 2 was significantly higher than the hospital 1 (P < 0.001). There is any relationship between bacterial contamination and the number of people in stations (P = 0.13). Spearman relationship shows a positive relationship between station temperature and number of colonies (P = 0.02, R = 0.3)

Staphylococcus aureus was detected in all air samples of two hospitals. The type of air gram-negative bacteria in different stations has been presented in [Table 6].
Table 6: Type of gram-negative bacterial contamination

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The antibiotic resistance test of Staphylococcus aureus in two hospitals is specified in [Table 7].
Table 7: Resistant of Staphylococcus aureus isolated from samples

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[Table 8] shows the antibiotic resistance of gram-negative bacteria in air samples.
Table 8: Resistant of gram-negative bacteria isolated from samples

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Staphylococcus aureus and Escherichia coli from hospital 1 are sensitive to the tested antibiotics but staphylococcus aureus and Escherichia coli isolated from hospital 2 are resistant to all studied antibiotics except amikacin.


  Discussion Top


The presence of bioaerosols in the air is the probable cause of respiratory diseases. Bio-aerosols are found in most of the surrounded places. Even because of different internal sources that are mostly related to human activities, high concentrations of bio-aerosols was reported for indoors.[1]

In the present study, different wards of two hospitals with the top grade of health rank are evaluated. The results showed that bacterial contamination in both hospitals was higher than the WHO based recommendation of 100 CFU/m3[27] and the standard of ACGIH (75 CFU/m3).[28] Exposure to levels higher than standards is also reported in other studies. In the study of Auguatowka bacterial airborne is measured between 436 and 257 CFU/m3 in a hospital of Poland.[29] Exposure to bioaerosols in indoor such as hospitals is inevitable. However bio-aerosols contamination is bearable for most healthy people, but it is not acceptable for susceptible people.[23] A high level of bacterial contamination could be related to the ventilation system, outdoor microbial loading, numbers, and human activities.[16],[23],[30],[31]

In the present study, one of the stations with high colony count was reported in the cardiology inpatient ward of two hospitals while the least colony count was reported in the laboratory. High level of bacterial contamination in cardiology station due to a high number of patients and visitors. In the study of Hosseinzadeh et al., Emergency and Obstetrics & GYN wards had the highest level of bio-aerosols concentration.[16] The use of unsterile equipment and a high number of patients increase bacterial contamination in our study.[32] However, Cabo Verde reported a maximum level of 495–499 CFU/m3 of bacteria in the surgical ward.[31] It seems to upgrade health standards, it is needed a suitable ventilation system, appropriate personnel clothing, controlling the number of people in wards, and applying discipline to minimize bacterial contamination.[33]

CCU and ICU stations should be in the extent of a clean room with a high ventilation rate. Bacterial level of ICU and CCU wards in studied hospitals was higher than the ACGIH suggested range while was lower than other wards. However, the source of microorganisms should only be related to patients and the activity of personals while visitors entering these wards are limited.[30]

The results of the antibiotic resistance test show that both gram-negative and gram-positive bacteria are resistant to a number of antibiotics, especially in Hospital 2. In this study, amikacin was the only antibiotic to which all bacteria were sensitive. In hospital 2, the resistance of Staphylococcus aureus was almost 100%. In the study of Aligholi et al., the resistance of Staphylococcus aureus to the oxacillin was 47%, which was more than hospital 1 and less than hospital 2 in our study.[34]

Ghanem and Haddadin examined the antibiotic resistance of E. coli in hospital environmental samples. In the disc diffusion test, despite its high resistance to various antibiotics, E. coli was sensitive to imipenem and amikacin which was similar to our study.[35]


  Conclusion Top


Results of this study show that 86.7% of studied stations in hospital 1 and all wards of hospital 2 have a bacterial concentration higher than the allowed range of ACGIH (75 CFU/m3) and WHO (100 CFU/m3). Therefore, even though both hospitals were at the highest grade of health rank, they still had bacterial contamination above the allowable level of the ACGIH and WHO standards. Staphylococcus aureus was identified in most wards of the tow hospital. Acinetobacterlwoffii and  Salmonella More Details typhimuriu were the most abundant and least gram-negative bacteria in hospital 1 respectively. In hospital 2, Pseudomonas aeuringos and Klebsiella pneumonia were the most abundant gram-negative bacteria in the sampling stations. At Hospital 2, antibiotic resistance tests showed that both gram-negative and gram-positive bacteria were resistant to most antibiotics.

Microorganisms can enter the hospital′s air via different ways and their complete removal is not possible; however, for keeping the health of patients and personnel, air bacterial contamination should be kept at the lowest possible level. Using an appropriate ventilation system, effective infection control processes, and supervision systems are required to decrease the bio-aerosols level in hospitals.[36]

Key Messages

  • Bacterial contamination and antibiotic resistance in hospital 2 was significantly higher than in the first hospital
  • Air bacterial contamination in the inpatient ward and the operating room was higher than other sections
  • Bacterial contamination in all of the stations in hospital 2 and 87% of samples in hospital 1 was higher than the acceptable range of ACGIH.


Financial support and sponsorship

Occupational Health Engineering, School of Public Health and Safety, Shahid Beheshti University of Medical Sciences, Tehran, Iran

Conflicts of interest

There are no conflicts of interest.



 
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    Tables

  [Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6], [Table 7], [Table 8]



 

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