scholarly journals Can Humidifier Reservoir Bacteria Colonize the Circuit During Mechanical Ventilation?

2022 ◽  
Author(s):  
Tian-Ran. Li ◽  
Lan-Ping. Shi ◽  
Yong-Gang. Jia ◽  
Ricky Wing Tong. Lau ◽  
Xia-Zhen. Pan
Keyword(s):  
Mechanical Ventilation ◽  
Bacterial Growth ◽  
Water Samples ◽  
Bacterial Colonization ◽  
Brain Heart Infusion ◽  
Sterile Water ◽  
Ventilator Circuit ◽  
Bacterial Concentration ◽  
Water Group

Abstract Background:Although the circuit condensate, an ideal bacterial reservoir, may flow into the humidifier reservoir (HR), no study has investigated if HR-colonized bacteria colonize other circuit locations with airflow. Therefore, the objective of this study was to explore if bacterial growth in the HR leads to bacterial colonization in the ventilator circuit. Methods: A randomized controlled experiment was performed in a public tertiary hospital in Guangdong Province, China. In vitro mechanical ventilation models (n = 60), divided into sterile water samples (n = 30) and broth samples (n = 30), were established. Sterile water was used for humidification in the ventilation models. The sterile water group contained either Acinetobacter baumannii (n = 15) or Pseudomonas aeruginosa (n = 15) in humidifier water. The broth group was similar to the sterile water group, but brain heart infusion broth was added to the HR. After 24, 72, and 168 h of continuous ventilation, bacteria in the humidifier water and at different circuit locations were sampled and cultured, and the results were analyzed by the Chi-square test. The difference in bacterial concentration at the HR outlet was analyzed by the F test, and P < 0.05 was considered statistically significant.Results:Bacterial culture results of the sterile water samples were negative. Bacteria in the humidifier water continued to proliferate in the broth group, and the bacterial concentration at different times was not significantly different (P > 0.05). With prolonged ventilation, the bacterial concentration at the HR outlet increased (P < 0.05). During continuous ventilation, no bacterial growth occurred at 10 cm from the HR outlet and the Y-piece of the ventilator circuit. The bacterial concentration at the HR outlet was higher in the P. aeruginosa group than in the A. baumannii group (P < 0.05).Conclusions:Sterile water in the HR was not conducive to bacterial growth. Although bacteria grew in the HR and could reach the HR outlet, colonization of other circuit locations was unlikely.

scholarly journals An In vitro Assessment of Antibacterial Activity of Three Self-etching Primers Against Oral Microflora

2017 ◽  
Vol 7 ◽  
pp. 181-187
Author(s):  
Sneha Dipak Shinde ◽  
Vikram Pai ◽  
R. Vijay Naik
Keyword(s):  
Antibacterial Activity ◽  
Growth Inhibition ◽  
Bacterial Colonization ◽  
Brain Heart Infusion ◽  
Dilution Method ◽  
Filter Paper Disc ◽  
Oral Microflora ◽  
Agar Diffusion Test ◽  
Serial Dilution Method

Aims This study aims to evaluate and compare the antibacterial activity of three self-etching primers (SEP), namely, Transbond plus, Reliance, and Gluma against commonly encountered oral microflora (Streptococcus mutans, Lactobacillus acidophilus, and Actinomyces viscosus). Subjects and Methods The antibacterial activity of the three SEPs was examined against microorganisms using agar diffusion test (ADT) and minimum inhibitory concentration (MIC). In ADT, Whatman’s filter paper disc of 5 mm was loaded with primer and polymerized. This was placed on previously inoculated brain heart infusion and blood agar plates and was incubated for 48– 72 h at 37°C according to the microorganism. For assessing MIC serial dilution method was used. Statistical Analysis Used Data were analyzed with Kruskal–Wallis (P < 0.001) and Mann–Whitney tests. Results Only Transbond plus SEP and Reliance SEP produced a clear growth inhibition halo against S. mutans, L. acidophilus and A. viscosus. Gluma SEP did not show any growth inhibition halo against S. mutans, L. acidophilus, and A. viscosus. Conclusions TSEP and Reliance SEP did show antibacterial activity in an in vitro environment. Therefore, this study concludes that the use of these SEPs may contribute to a reduction in bacterial colonization.

scholarly journals Incidence and Pattern of Bacterial Growth in Propofol Vial - An In vitro Study

2016 ◽  
Vol 06 (02) ◽  
pp. 051-056
Author(s):  
U. S. Raveendra ◽  
Rashmi Soori ◽  
Vimal Kumar Karnekar ◽  
Swathi N. Nayak ◽  
Anand Bangera
Keyword(s):  
Bacterial Growth ◽  
Pearson Correlation ◽  
Brain Heart Infusion ◽  
In Vitro Study ◽  
Surgical Site Infections ◽  
Blood Stream ◽  
Categorical Variables ◽  
Bacillus Species ◽  
Febrile Episodes

Abstract Introduction- Propofol vials are often used in parts or are opened and left unattended. This has lead to blood stream infections, surgical site infections and acute febrile episodes. A prospective observational study was undertaken to know the incidence and pattern of bacterial growth in samples of Propofol in tropical climate. Materials and methods- Samples were collected from vials of propofol of different brands, both with and without edetate at different time intervals with relation to room temperature. Each sample of 1ml were inoculated in Brain Heart Infusion (BHI) and incubated for 48hours. Presence of bacterial growth and their pattern were studied. Statistical analysis used- Paired t test for categorical variables and for non categorical variables Levine's test and Pearson correlation. Results- Overall 42.26% of samples showed bacterial growth. The incidence was more in samples of propofol without edetate (43.75%) compared to samples with edetate (41.97 %). Most common organism was Staphylococcus aureus, followed by Enterococcus, Acinetobacter, Bacillus species, Pseudomonas and Staphylococcus citrus. Conclusion- Propofol vial once opened favours bacterial colonisation and growth. Adding edetate to propofol has not shown much benefit in decreasing the incidence.

Endotracheal Tubes Coated with Antiseptics Decrease Bacterial Colonization of the Ventilator Circuits, Lungs, and Endotracheal Tube

2004 ◽  
Vol 100 (6) ◽  
pp. 1446-1456 ◽  
Author(s):  
Lorenzo Berra ◽  
Lorenzo De Marchi ◽  
Zu-Xi Yu ◽  
Patrice Laquerriere ◽  
Andrea Baccarelli ◽  
...  
Keyword(s):  
Endotracheal Tube ◽  
Bacterial Growth ◽  
Laser Scanning ◽  
Pathogenic Bacteria ◽  
Bacterial Colonization ◽  
Bacterial Biofilm ◽  
Control Group ◽  
Study Group ◽  
Ventilator Circuit ◽  
Bacterial Cultures

Background Formation of a bacterial biofilm within the endotracheal tube (ETT) after tracheal intubation is rapid and represents a ready source of lung bacterial colonization. The authors investigated bacterial colonization of the ventilator circuit, the ETT, and the lungs when the ETT was coated with silver-sulfadiazine and chlorhexidine in polyurethane, using no bacterial/viral filter attached to the ETT. Methods Sixteen sheep were randomized into two groups. Eight sheep were intubated with a standard ETT (control group), and eight were intubated with a coated ETT (study group). Animals were mechanically ventilated for 24 h. At autopsy, the authors sampled the trachea, bronchi, lobar parenchyma, and ETT for quantitative bacterial cultures. Qualitative bacterial cultures were obtained from the filter, humidifier, inspiratory and expiratory lines, and water trap. ETTs were analyzed with light microscopy, scanning electron microscopy, and laser scanning confocal microscopy. Results In the control group, all eight ETTs were heavily colonized (10(5)-10(8) colony-forming units [cfu]/g), forming a thick biofilm. The ventilator circuit was always colonized. Pathogenic bacteria colonized the trachea and the lungs in five of eight sheep (up to 10(9) cfu/g). In the study group, seven of eight ETTs and their ventilator circuits showed no growth, with absence of a biofilm; one ETT and the respective ventilator circuit showed low bacterial growth (10(3)-10(4) cfu/g). The trachea was colonized in three sheep, although lungs and bronchi showed no bacterial growth, except for one bronchus in one sheep. Conclusions Coated ETTs induced a nonsignificant reduction of the tracheal colonization, eliminated (seven of eight) or reduced (one of eight) bacterial colonization of the ETT and ventilator circuits, and prevented lung bacterial colonization.

scholarly journals Contaminação microbiológica de fios retratores: um estudo in vitro

2017 ◽  
Vol 32 (1) ◽  
pp. 47
Author(s):  
Marina Lucia Cumerlato ◽  
Darlene Ribeiro dos Santos Gerzson ◽  
Edison Maciel Nunes De Souza Filho ◽  
Everton Ribeiro Dos Santos ◽  
Marina Lucia Cumerlato ◽  
...  
Keyword(s):  
Infection Control ◽  
Bacterial Growth ◽  
Dental Care ◽  
Growth Analysis ◽  
Culture Medium ◽  
Brain Heart Infusion ◽  
In Vitro Study ◽  
Vitro Study

OBJECTIVE: Dental care has been particularly concerned with sterilization of instruments and materials. In this context, the methods used for infection control are essential to ensure patients’ safety. This in vitro study aimed to test gingival retraction cords taken from factory- sealed containers for the presence of contamination. Three commercial brands of retraction cords were analyzed: Retraflex®, Pró-Retract®, and Ultrapack®.METHODS: The sample consisted of 10 1-cm segments of retraction cords of each commercial brand (n = 30). For bacterial growth analysis, 30 test tubes containing sterile brain heart infusion (BHI) as the culture medium were used. Bacterial growth was considered positive in tubes in which the BHI broth became turbid.RESULTS: Of 30 test tubes with retraction cords, six showed turbidity  and were considered contaminated: three tubes with Retraflex®, one tube with Pro-Retract®, and two tubes with Ultrapack®, accounting for 20% of the total sample.CONCLUSIONS: The present findings showed that some retraction cords received from the manufacturers were contaminated with microorganisms. Thus, extra caution should be taken when using these materials, and further studies should be conducted.

Bacterial Colonization in Humidifying Cascade Reservoirs After 24 and 48 Hours of Continuous Mechanical Ventilation

1987 ◽  
Vol 8 (5) ◽  
pp. 200-203 ◽  
Author(s):  
Theresa A. Goularte ◽  
Marie Manning ◽  
Donald E. Craven
Keyword(s):  
Mechanical Ventilation ◽  
Bacterial Colonization ◽  
Heated Humidifier ◽  
Mechanical Ventilator ◽  
Reservoir Temperature ◽  
Mechanical Ventilators ◽  
Cascade Reservoirs ◽  
Reservoir Fluid ◽  
Bacterial Aerosols

AbstractWe evaluated levels of bacterial colonization in the humidifying cascade reservoirs of 466 mechanical ventilators; 326 reservoirs were cultured after 24 hours and 140 were cultured after 48 hours of continuous mechanical ventilation. Bacterial colonization was absent in 284 (87.1%) of the humidifier reservoirs sampled at 24 hours and 125 (89.3%) of the reservoirs cultured at 48 hours. Levels of bacterial colonization in the remaining humidifiers were low (<100 organisms/mL). The median temperature recorded in the reservoir fluid of 30 different ventilators was 50°C (range 40° to 60°C). In vitro seeding of reservoir fluid at 50°C with 106 organisms/mL of four different species of nosocomial gram-negative bacilli and Staphylococcus aureus demonstrated rapid killing of all five strains over a 6-hour incubation period, and no significant bacterial aerosols were detected. Rates and levels of bacteria in heated humidifier reservoirs are low and nosocomial pathogens survive poorly at the median reservoir temperature of 50°C. We conclude that the heated humidifier reservoir on a mechanical ventilator is an unlikely source of colonization or bacterial aerosols, and therefore it can be changed every 48 hours with the ventilator tubing.

scholarly journals Subdiffusive motion of bacteriophage in mucosal surfaces increases the frequency of bacterial encounters

2015 ◽  
Vol 112 (44) ◽  
pp. 13675-13680 ◽  
Author(s):  
Jeremy J. Barr ◽  
Rita Auro ◽  
Nicholas Sam-Soon ◽  
Sam Kassegne ◽  
Gregory Peters ◽  
...  
Keyword(s):  
Bacterial Infections ◽  
Bacterial Colonization ◽  
Mucin Secretion ◽  
Bacterial Concentration ◽  
Culture Cells ◽  
Complex Interactions ◽  
Mucosal Surfaces ◽  
Normal Diffusion ◽  
T4 Phage

Bacteriophages (phages) defend mucosal surfaces against bacterial infections. However, their complex interactions with their bacterial hosts and with the mucus-covered epithelium remain mostly unexplored. Our previous work demonstrated that T4 phage with Hoc proteins exposed on their capsid adhered to mucin glycoproteins and protected mucus-producing tissue culture cells in vitro. On this basis, we proposed our bacteriophage adherence to mucus (BAM) model of immunity. Here, to test this model, we developed a microfluidic device (chip) that emulates a mucosal surface experiencing constant fluid flow and mucin secretion dynamics. Using mucus-producing human cells andEscherichia coliin the chip, we observed similar accumulation and persistence of mucus-adherent T4 phage and nonadherent T4∆hocphage in the mucus. Nevertheless, T4 phage reduced bacterial colonization of the epithelium >4,000-fold compared with T4∆hocphage. This suggests that phage adherence to mucus increases encounters with bacterial hosts by some other mechanism. Phages are traditionally thought to be completely dependent on normal diffusion, driven by random Brownian motion, for host contact. We demonstrated that T4 phage particles displayed subdiffusive motion in mucus, whereas T4∆hocparticles displayed normal diffusion. Experiments and modeling indicate that subdiffusive motion increases phage–host encounters when bacterial concentration is low. By concentrating phages in an optimal mucus zone, subdiffusion increases their host encounters and antimicrobial action. Our revised BAM model proposes that the fundamental mechanism of mucosal immunity is subdiffusion resulting from adherence to mucus. These findings suggest intriguing possibilities for engineering phages to manipulate and personalize the mucosal microbiome.

scholarly journals Variability of bacterial behavior in the mammalian gut captured using a growth-linked single-cell synthetic gene oscillator

2018 ◽  
Author(s):  
David T Riglar ◽  
David L Richmond ◽  
Laurent Potvin-Trottier ◽  
Andrew A Verdegaal ◽  
Alexander D Naydich ◽  
...  
Keyword(s):  
Single Cell ◽  
Bacterial Growth ◽  
Bacterial Population ◽  
Bacterial Colonization ◽  
Growth Conditions ◽  
Inflammatory Conditions ◽  
Genetic Oscillator ◽  
Constant Period

AbstractThe dynamics of the bacterial population that comprises the gut microbiota plays key roles in overall mammalian health. However, a detailed understanding of bacterial growth within the gut is limited by the inherent complexity and inaccessibility of the gut environment. Here, we deploy an improved synthetic genetic oscillator to investigate dynamics of bacterial colonization and growth in the mammalian gut under both healthy and disease conditions. The synthetic oscillator, when introduced into both Escherichia coli and Salmonella Typhimurium maintains regular oscillations with a constant period in generations across growth conditions. We determine the phase of oscillation from individual bacteria using image analysis of resultant colonies and thereby infer the number of cell divisions elapsed. In doing so, we demonstrate robust functionality and controllability of the oscillator circuit’s activity during bacterial growth in vitro, in a simulated murine gut microfluidic environment, and in vivo within the mouse gut. We determine different dynamics of bacterial colonization and growth in the gut under normal and inflammatory conditions. Our results show that a precise genetic oscillator can function in a complex environment and reveal single cell behavior under diverse conditions where disease may create otherwise impossible-to-quantify variability in growth across the population.

An In Vitro Analysis of Sodium Hypochlorite Decontamination for the Reuse of Implant Healing Abutments

2020 ◽  
Author(s):  
Ahmad Almehmadi
Keyword(s):  
Sodium Hypochlorite ◽  
Bacterial Culture ◽  
Brain Heart Infusion ◽  
In Vitro Study ◽  
Vitro Study ◽  
Sem Images ◽  
Streptococcus Sanguis ◽  
Implant Dentistry ◽  
Vitro Analysis

Abstract The re-use of healing abutments (HAs) has become common practice in implant dentistry for economic concerns and the aim of this in-vitro study was to assess the effect of sodium hypochlorite (NaOCl) in decontamination of HAs. 122 HAs (Used and sterilized n=107; New n=15) were procured from 3 centers, of which 3 samples were discarded due to perforation in sterilization pouch.  For sterility assessment, the used HAs (n=80) were cultured in Brain Heart Infusion Broth (BHI) and Potato Dextrose Agar (PDA), bacterial isolates were identified in 7 samples. Also, 24 used HAs were stained with Phloxine B, photographed and compared to new HAs (n=5). Scanning electron microscope (SEM) assessed the differences between the two sets of HAs, following which the 7 contaminated HAs along with 24 used HAs from staining experiment (Total=31) were subsequently treated with sodium hypochlorite (NaOCl) and SEM images were observed. About 8.75% of HAs tested positive in bacterial culture; Streptococcus sanguis, Dermabacter hominis, Staphylococcus haemolyticus, and Aspergillus species were isolated. Phloxine B staining was positive for used and sterilized HAs when compared to controls. The SEM images revealed deposits in the used HAs and although treatment with NaOCl eliminated the contamination of cultured HAs, the SEM showed visible debris in the HA thread region. This in-vitro study concluded that SEM images showed debris in used HAs at screw-hole and thread regions even though they tested negative in bacterial culture. The treatment with NaOCl of used HAs showed no bacterial contamination but the debris was observed in SEM images. Future studies on the chemical composition, biological implications, and clinical influence is warranted before considering the reuse of HAs.

Effect of C6-Volatiles on Bioluminescent Plant Pathogens

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 557d-557
Author(s):  
Jennifer Warr ◽  
Fenny Dane ◽  
Bob Ebel
Keyword(s):  
Biological Activity ◽  
Bacterial Growth ◽  
Xanthomonas Campestris ◽  
Plant Pathogens ◽  
Genetically Engineered ◽  
The Other ◽  
Computer Assisted ◽  
Signal Molecules ◽  
Low Concentrations

C6 volatile compounds are known to be produced by the plant upon pathogen attack or other stress-related events. The biological activity of many of these substances is poorly understood, but some might produce signal molecules important in host–pathogen interactions. In this research we explored the possibility that lipid-derived C6 volatiles have a direct effect on bacterial plant pathogens. To this purpose we used a unique tool, a bacterium genetically engineered to bioluminesce. Light-producing genes from a fish-associated bacterium were introduced into Xanthomonas campestris pv. campestris, enabling nondestructive detection of bacteria in vitro and in the plant with special computer-assisted camera equipment. The effects of different C6 volatiles (trans-2 hexanal, trans-2 hexen-1-ol and cis-3 hexenol) on growth of bioluminescent Xanthomonas campestris were investigated. Different volatile concentrations were used. Treatment with trans-2 hexanal appeared bactericidal at low concentrations (1% and 10%), while treatments with the other volatiles were not inhibitive to bacterial growth. The implications of these results with respect to practical use of trans-2 hexanal in pathogen susceptible and resistant plants will be discussed.

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