scholarly journals Invitro filtration efficiency for selected face masks to bacteria with a size smaller than SARS-CoV-2 respiratory droplet

2020 ◽  
Author(s):  
Maryam Amour ◽  
Hussein H. Mwanga ◽  
George M. Bwire
Keyword(s):  
Escherichia Coli ◽  
Double Layer ◽  
Ambient Air ◽  
Filtration Efficiency ◽  
Cotton Cloth ◽  
Colony Forming Units ◽  
Spread Of Infection ◽  
N95 Respirators ◽  
And Control ◽  
Respiratory Droplets

Abstract Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) can be transmitted between people through respiratory droplets (droplet particles are >5-10 μm in diameter). We conducted an invitro experiment to determine the filtration efficiency for selected face masks (cloth and medical face masks and N95 respirators) to bacteria with a size (0.5-1.5 μm in diameter) smaller than SARS-CoV-2 respiratory droplet. Bacteria suspension was prepared using normal saline (NaCl) and bacteria (Staphylococcus aureus and Escherichia coli) and maintained at a turbidity of 0.5 MacFarland. The suspensions was put in a 100ml plastic spray bottle (with an approximated 250 μl and flow rate of 31.5 ft3/min per spray) and then a single spray was performed to the test masks. Swabbing was done to unsprayed side of the test mask within 0 and after 4 hrs. The swab was streaked on CLED media then incubated for 48 hours at 37oC in ambient air. Bacterial filtration efficiency (BFE) was determined as the proportions of colony forming units (CFUs) between the test and control mask. The selected face masks had BFE of 100% and >99% for medical and double layer cotton cloth masks, respectively. This study supports the use of cotton cloth (at least double layer) face coverings in public settings where other social distancing measures are difficult to maintain to prevent the spread of infection from the wearer.

scholarly journals Bacteria Filtration Efficiency of Different Face Masks Worn during COVID-19 Pandemic in North-Eastern Tanzania: An In Vitro Study

2020 ◽  
Author(s):  
Marianne Gnanamuttupulle ◽  
Shilanaiman Hilary Ntundu ◽  
Oliver Henke ◽  
Abias Anthon Moshi ◽  
David Msuya ◽  
...  
Keyword(s):  
Double Layer ◽  
Single Layer ◽  
In Vitro Study ◽  
Filtration Efficiency ◽  
Cotton Cloth ◽  
Bacterial Suspension ◽  
Surgical Masks ◽  
North Eastern ◽  
N95 Respirators

Increased demand for wearing face masks, lack of surgical masks and N95 respirators during the coronavirus pandemic created alternative needs for cloth masks. Therefore, to determine filtration efficacy, reusability and duration of wearing new and hand washed cloth masks, the bacteria filtration efficacy was tested using Staphylococcus aureus and Escherichia coli. Cotton cloth masks; single layer without pleats and with pleats, double layer with canvas filter in the middle, double layer with stiff filter in the middle, double layer with pleats on both sides and locally made and imported surgical masks and N95 respirators were used. Bacterial suspension was sprayed over outer surface and swabbed from inner surface at 0hrs, 4thhr, 8thhr and 12thhr. Similar procedure was performed to hand washed and ironed cotton cloth masks. After 24 hours of incubation, single layer without pleats and with pleats had no filtration efficacy(0-100%). Double layer with stiff filter in the middle and double layer with pleats on both sides had higher filtration efficacy(99.96-100%), this filtration efficacy remained up to three occasions of hand washing with soap and water, conferring protection up to 12hours. Filtration efficacy of surgical masks made locally, imported and N95 respirators were 90-100%, 99.99-100%, and 99.99-100% respectively.

scholarly journals Occurrence of Escherichia coli non-susceptible to quinolones in faecal samples from fluoroquinolone-treated, contact and control pigs of different ages from 24 Swiss pig farms

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Morena Amsler ◽  
Katrin Zurfluh ◽  
Sonja Hartnack ◽  
Xaver Sidler ◽  
Roger Stephan ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Bacterial Infections ◽  
Farm Animals ◽  
Resistant Bacteria ◽  
Control Group ◽  
Reduced Frequency ◽  
Colony Forming Units ◽  
Faecal Samples ◽  
And Control

Abstract Background Despite their indispensability in human medicine, fluoroquinolones (FQ) are used for the treatment of bacterial infections in farm animals which increases the risk of transferring FQ-resistant bacteria into the environment and via the food chain to humans. The objectives of this observational study were to follow-up of the presence of quinolone non-susceptible Escherichia coli (QNSE) qualitatively and quantitatively in faecal samples of pigs at four time points (2 weeks old, 4 weeks old, 2 weeks post weaning and during fattening period). Moreover differences between groups of FQ-treated pigs, pigs with contact to treated pigs and control pigs were investigated. Additionally, quinolone and FQ resistance of Escherichia coli isolates of the faecal samples were investigated by determining minimum inhibitory concentrations (MICs). Results 40.9% of 621 fecal samples contained QNSE. Proportion of samples with detectable QNSE from treated and contact pigs did not differ significantly and were highest in piglets of 2 and 4 weeks of age. However, the proportions of samples with QNSE were significantly lowest in control pigs (7/90; 7.8%; CI = 3.5–14.7%) among all groups. Also, the number of colony-forming units was lowest in both weaners and fattening pigs of the control group compared to treated and contact groups. Following CLSI human breakpoints, in total, 50.4% out of 254 isolates in faecal samples were intermediate or resistant to ciprofloxacin. Conclusions QNSE were present in faeces of pigs independent of age or FQ background but significantly less were found in pigs from farms without FQ usage. Due to the long half-life of FQ, it is likely that only a prolonged absence of fluoroquinolone treatments in pig farming will lead to a reduced frequency of QNSE in the farm environment. Solutions need to be found to minimise the emergence and transfer of quinolone and FQ-resistant bacteria from treated pigs to contact pigs and to farms without FQ usage.

scholarly journals Disinfection of N95 Respirators with Ozone

2020 ◽  
Author(s):  
Edward P Manning ◽  
Matthew D Stephens ◽  
Sannel Patel ◽  
Sylvie Dufresne ◽  
Bruce Silver ◽  
...  
Keyword(s):  
Ambient Air ◽  
Filtration Efficiency ◽  
Ozone Exposure ◽  
Healthcare Personnel ◽  
First Report ◽  
High Level ◽  
N95 Respirators ◽  
Airtight Chamber ◽  
Ozone Disinfection ◽  
Chamber Exposure

The coronavirus disease 2019 crisis is creating a shortage of personal protective equipment (PPE), most critically, N95 respirators for healthcare personnel. Our group was interested in the feasibility of ozone disinfection of N95 respirators as an alternative for healthcare professionals and organizations that might not have access to other disinfection devices. We tested the effectiveness of ozone on killing Pseudomonas aeruginosa (PsA) on three different N95 respirators: 3M 1860, 3M 1870, and 3M 8000. We used an ozone chamber that consisted of: an airtight chamber, an ozone generator, an ozone destruct unit, and an ozone UV analyzer. The chamber was capable of concentrating ozone up to 500 parts per million (ppm) from ambient air, creating an airtight seal, and precisely measuring ozone levels within the chamber. Exposure to ozone at 400 ppm with 80% humidity for two hours effectively killed bacteria on N95 respirators, types 1860, 1870, and 8000. There were no significant changes in filtration efficiency of the 1860 and 1870 type respirators for up to ten cycles of ozone exposure at similar conditions. There was no change in fit observed in the 1870 type respirator after ozone exposure. There was no significant change in the strap integrity of the 1870 type respirator after ozone exposure. Tests for filtration efficiency were not performed on the 8000 type respirator. Tests for fit or strap integrity were not performed on the 8000 or 1860 type respirators. This study demonstrates that an ozone application achieves a high level of disinfection against PsA, a vegetative bacteria that the CDC identifies as more difficult to kill than medium sized viruses such as SARS-CoV-2 (Covid-19). Furthermore, conditions shown to kill these bacteria did not damage or degrade respirator filtration. This is the first report of successful disinfection of N95 PPE with ozone of which the authors are aware. It is also the first report, to the authors' knowledge, to identify necessary conditions for ozone to kill organisms on N95 masks without degrading the function of N95 filters.

scholarly journals Effect of gamma sterilization on filtering efficiency of various respiratory face-masks

2020 ◽  
Author(s):  
Amit Kumar ◽  
D.N. Sangeetha ◽  
Ramani Yuvaraj ◽  
M. Menaka ◽  
V. Subramanian ◽  
...  
Keyword(s):  
Gamma Radiation ◽  
Double Layer ◽  
Flow Rate ◽  
Woven Fabric ◽  
Protective Measure ◽  
Cotton Cloth ◽  
Before And After ◽  
Filtering Efficiency ◽  
Single Use ◽  
Respiratory Droplets

Abstract Three types of respiratory masks viz N95, non-woven fabric and double layer cotton cloth are being used as an essential inhalation protective measure against COVID-19 by suppressing the entry of respiratory droplets. The filtering efficiency of these masks were tested before and after sterilization using gamma radiation for the two flow rate conditions corresponding normal breath rate (20 lpm) and during sneezing/coughing (90 lpm). Sterilization is carried out using a gamma irradiator containing Co-60 source for the two dose exposures viz. 15kGy and 25kGy. The filtering efficiency for surgical (non-woven fabric) and double layer cotton cloth mask is found to vary from 18% to 22% for the cumulative particle of size ≥ 0.3µm in both un-irradiated and irradiated condition.The filtration efficiency of N95 mask is found to be reduced to 70% for the most penetrating particle size (0.3 µm) with the flow rate of 20 lpm and further reduced for particles in the range of 0.1 and 0.2µm with flow rate of 90 lpm. The reduction in efficiency after gamma sterilization is associated with reduction of electrostatic interaction of filter medium with particles laden in the air stream.Even with reduced filtering efficiency due to gamma sterilization, the N95 masks are much superior than the surgical and cloth masks.Instead of disposing N95 mask after single use, they can be reused a few times as N70 mask during this pandemic crisis after sterilization using gamma radiation.

Electrode for Electric Double Layer Capacitor Made of Carbonized and Activated Cotton Cloth

2014 ◽  
Vol 134 (5) ◽  
pp. 360-361
Author(s):  
Masumi Fukuma ◽  
Takayuki Uchida ◽  
Yukito Fukushima ◽  
Jinichi Ogawa ◽  
Katsumi Yoshino
Keyword(s):  
Double Layer ◽  
Electric Double Layer ◽  
Cotton Cloth ◽  
Electric Double Layer Capacitor ◽  
Double Layer Capacitor

Study effect of crude extracts of Hibiscus sabdarifa L. on some Enterobacteriaceae

2018 ◽  
Vol 9 (SPL1) ◽  
Author(s):  
Sabreen A Kamal ◽  
Ishraq A Salih ◽  
Hawraa Jawad Kadhim ◽  
Zainab A Tolaifeh
Keyword(s):  
Escherichia Coli ◽  
Ethyl Acetate ◽  
Bacterial Growth ◽  
Chemical Compounds ◽  
Inhibition Zone ◽  
Crude Extracts ◽  
And Control

Red rose or roselle (beauty rose ) is natively known as red tea belong to Malvaceae, it is flowers use traditionally for antihypertensive hepato protective, anticancer,antidiabetic,antibacterial, cytotoxicity and antidiarreal, By preparing red tea from it's flower. In this study, we extract chemical compounds by using two solvent which are Ethanol, Ethyl acetate. so we can extract Anthocyanin which is responsible for red colour of flower with many chemical compounds. then study the effect of these extracts on 5 genera from Enterobacteriacaea which can cause diarrheae (Shigella, Salmonella, Escherichia coli, Proteus and Klebsiella ) by preparing 3 concentrations for each solvent (250, 500, 750 ) mg/ml, and control then compare with two antibiotic (Azereonam 30 mg/ml and Bacitracin 10 mg/ml ) these extracts revealed obvious inhibition zone in bacterial growth.

scholarly journals High prevalence of qnrA and qnrB genes among fluoroquinolone-resistant Escherichia coli isolates from a tertiary hospital in Southern Nigeria

2021 ◽  
Vol 45 (1) ◽  
Author(s):  
Chibuzor M. Nsofor ◽  
Mirabeau Y. Tattfeng ◽  
Chijioke A. Nsofor
Keyword(s):  
Escherichia Coli ◽  
Susceptibility Testing ◽  
Tertiary Hospital ◽  
Vaginal Swab ◽  
Fluoroquinolone Resistance ◽  
E Coli ◽  
Diffusion Technique ◽  
High Prevalence ◽  
Polymerase Chain ◽  
And Control

Abstract Background This study was aimed to determine the prevalence of qnr genes among fluoroquinolone-resistant Escherichia coli (FREC) isolates from Nigeria. Antimicrobial susceptibility testing was performed by disc diffusion technique. Polymerase chain reaction was used to identify Escherichia coli (E. coli) and for the detection of qnr genes. Results A total of 206 non-duplicate E. coli were isolated from 300 clinical specimens analyzed. In all, 30 (14.6%) of these isolates were FREC; the resistance to fluoroquinolones among these 30 FREC showed 80% (24), 86.7% (26), 86.7% (26), 100% (30), 86.7% (26), 93.3% (28) and 86.7% (26) were resistant to pefloxacin, ciprofloxacin, sparfloxacin, levofloxacin, nalidixic acid, ofloxacin and moxifloxacin, respectively. The distribution of FREC among the various sample sources analyzed showed that 14%, 10%, 13.3%, 16.7% and 20% of the isolates came from urine, stool, high vaginal swab, endo cervical swab and wound swab specimens, respectively. More FREC were isolated from female samples 73.3% (22) compared to male samples 26.7% (8) and were more prevalent among the age group 26–35 years (40%). Twenty eight out of the 30 (93.3%) FREC isolates possessed at least one fluoroquinolone resistance gene in the form of qnrA 10 (33.3%) and qnrB 18 (60%), respectively; qnrS was not detected among the FREC isolates analyzed and 13.5% of the isolates possessed both the qnrA and qnrB genes. Phylogenetic analysis showed that these isolates were genetically diverse. Conclusions These findings suggest a possible resistance to fluoroquinolone is of high interest for better management of patients and control of antimicrobial resistance in Nigeria.

scholarly journals Turntable Paper-Based Device to Detect Escherichia coli

Micromachines ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 194
Author(s):  
Yung-Chih Wang ◽  
Yao-Hung Tsai ◽  
Ching-Fen Shen ◽  
Ming-Yao He ◽  
Yi-Chen Fu ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Infectious Diseases ◽  
Point Of Care ◽  
Multiple Integral ◽  
Enzyme Linked Immunosorbent Assay ◽  
Considerable Time ◽  
E Coli ◽  
Colony Forming Unit ◽  
Experimental Implementation ◽  
Colony Forming Units

Escherichia coli has been known to cause a variety of infectious diseases. The conventional enzyme-linked immunosorbent assay (ELISA) is a well-known method widely used to diagnose a variety of infectious diseases. This method is expensive and requires considerable time and effort to conduct and complete multiple integral steps. We previously proposed the use of paper-based ELISA to rapidly detect the presence of E. coli. This approach has demonstrated utility for point-of-care (POC) urinary tract infection diagnoses. Paper-based ELISA, while advantageous, still requires the execution of several procedural steps. Here, we discuss the design and experimental implementation of a turntable paper-based device to simplify the paper-based ELISA protocols for the detection of E. coli. In this process, antibodies or reagents are preloaded onto zones of a paper-based device and allowed to dry before use. We successfully used this device to detect E. coli with a detection limit of 105 colony-forming units (colony-forming unit [CFU])/mL.

Bacteriophages reduce Escherichia coli O157:H7 levels in experimentally inoculated sheep

2009 ◽  
Vol 89 (2) ◽  
pp. 285-293 ◽  
Author(s):  
S J Bach ◽  
R P Johnson ◽  
K. Stanford ◽  
T A McAllister
Keyword(s):  
Escherichia Coli ◽  
Oral Administration ◽  
Coliform Bacteria ◽  
Escherichia Coli O157 ◽  
Fecal Shedding ◽  
Total Coliforms ◽  
E Coli ◽  
Oral Inoculation ◽  
Experimental Treatments ◽  
And Control

Bacteriophage biocontrol has potential as a means of mitigating the prevalence of Escherichia coli O157:H7 in ruminants. The efficacy of oral administration of bacteriophages for reducing fecal shedding of E. coli O157:H7 by sheep was evaluated using 20 Canadian Arcott rams (50.0 ± 3.0) housed in four rooms (n = 5) in a contained facility. The rams had ad libitum access to drinking water and a pelleted barley-based total mixed ration, delivered once daily. Experimental treatments consisted of administration of E. coli O157:H7 (O157), E. coli O157:H7+bacteriophages (O157+phage), bacteriophages (phage), and control (CON). Oral inoculation of the rams with 109 CFU of a mixture of four nalidixic acid-resistant strains of E. coli O157:H7 was performed on day 0. A mixture of 1010 PFU of bacteriophages P5, P8 and P11 was administered on days -2, -1, 0, 6 and 7. Fecal samples collected on 14 occasions over 21 d were analyzed for E. coli O157:H7, total E. coli, total coliforms and bacteriophages. Sheep in treatment O157+phage shed fewer (P < 0.05) E. coli O157:H7 than did sheep in treatment O157. Populations of total coliforms and total E. coli were similar (P < 0.05) among treatments, implying that bacteriophage lysis of non-target E. coli and coliform bacteria in the gastrointestinal tract did not occur. Bacteriophage numbers declined rapidly over 21 d, which likely reduced the chance of collision between bacteria and bacteriophage. Oral administration of bacteriophages reduced shedding of E. coli O157:H7 by sheep, but a delivery system that would protect bacteriophages during passage through the intestine may increase the effectiveness of this strategy as well as allow phage to be administered in the feed.Key words: Escherichia coli O157:H7, bacteriophage, sheep, environment, coliforms

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