scholarly journals Evaluation of Sampling Methods for Detection of Pathogens from Steel Surfaces; Contact Plates, Foam Swabs, and Flocked Swabs

2020 ◽  
Vol 41 (S1) ◽  
pp. s230-s230
Author(s):  
Rolieria West ◽  
Laura Rose ◽  
Judith Noble-Wang
Keyword(s):  
Stainless Steel ◽  
Steel Surface ◽  
Sampling Methods ◽  
Agar Plate ◽  
Stainless Steel Surface ◽  
Plate Method ◽  
Surface Areas ◽  
Contact Plate ◽  
Composite Contact ◽  
Single Contact

Background: Contaminated healthcare surfaces can serve as reservoirs for the transmission of pathogens. Sensitive sampling methods are needed to investigate sources of pathogens for implementing effective disinfection strategies and thereby preventing environmental transmission. Conventional approaches employ swabs to sample environmental surfaces. Contact plates represent an alternative approach for sampling healthcare surfaces that does not require lab processing, though little is known about their performance. A contact plate is an agar plate that is overfilled with selective or nonselective media. It can be gently applied to the surface, then simply incubated at a temperature optimal for target organism (s), thus saving time and resources. Methods: In this study, contact plates containing trypticase soy agar with 5% sheep blood (TSAII), foam swabs, and flocked swabs were evaluated for their ability to recover 4 pathogens that persist on healthcare surfaces. Stainless-steel coupons (4 in2) were inoculated with the following pathogens (102 CFU): Acinetobacter baumannii (AB, strain type 12), carbapenemase-producing KPC+ Klebsiella pneumoniae (KP; ATCC BAA-1705); methicillin-resistant Staphylococcus aureus (MRSA; ATCC 43300); and vancomycin-resistant Enterococcus faecalis (VRE; Van A + 256). The plates were allowed to dry 1 hour. Sampling with CPs was performed in 2 ways; (1) a single contact plate was used to sample 1 stainless-steel surface and (2) a composite was collected by 3 sequential contact-plate samplings of the same stainless-steel surface. The contact plates were then incubated at 351C. Foam and flocked swabs were premoistened with phosphate-buffered saline + 0.02% polysorbate 80 (PBST) and were used to sample the stainless-steel coupons. Swabs were held for 1 hour and processed by sonication and vortexing in 5 mL of PBST, then the eluent was cultured and CFU counted. Mean percentage recoveries (%R) relative to the inoculum were calculated and compared. Results: When the %R for all 4 pathogens were pooled, the composite contact-plate sampling method yielded the highest, (P < .05) (66.0%; SD, 0.22), followed by the single contact plate method (39.7%; SD, 0.12), foam swab (32.9%; SD, 0.18), and flocked swab (20.3%; SD, 0.20). The composite contact plate method yielded the highest %R for VRE (102.1 %; SD, 0.17), and the lowest %R was observed when using flocked swabs to recover KP (6.3%; SD, 0.05). Conclusions: The contact-plate composite method may provide investigators with minimal environmental microbiology capacity an alternative method for environmental sampling and detection of organisms from surface areas (4 in 2) with low bioburden.Funding: NoneDisclosures: None

scholarly journals Development and Validation of a Thin-Layer Chromatographic Method for Determination of Chloramphenicol Residues on Pharmaceutical Equipment Surfaces

2005 ◽  
Vol 88 (5) ◽  
pp. 1555-1561 ◽  
Author(s):  
Irena Vovk ◽  
Breda Simonovska
Keyword(s):  
Stainless Steel ◽  
Detection Limit ◽  
Thin Layer ◽  
High Performance ◽  
Steel Surface ◽  
Stainless Steel Surface ◽  
Surface Areas ◽  
Absolute Detection Limit ◽  
Development And Validation

Abstract A thin-layer chromatographic (TLC) method with densitometric quantitation using the absorption reflectance mode at 280 nm was developed and validated for the determination of chloramphenicol residues in controlling pharmaceutical equipment cleanliness. Simulated samples at residue levels 0.5, 1, and 1.2 mg/m2 were prepared by spreading the calculated amount of chloramphenicol solution on a 10 dm2 stainless steel surface. After evaporation of the solvent, the residue was removed by 2 methanol-wetted cotton swabs, which were then extracted with methanol. The extract was applied on a high-performance TLC (HPTLC) silica gel F254 plate together with standards ranging from 10 to 60 ng. Plates were developed in a horizontal developing chamber from both sides (36 applications per plate) by using n-hexane–ethyl acetate (35 + 65, v/v) as developing solvent. The mean recovery (n = 6) at 1 mg/m2 was 95.8%, and the coefficient of variation was 5.8%. The absolute detection limit was 3 ng, and the quantitation limit 10 ng. The method detection limit was 0.3 mg/m2 by swabbing 2.5 dm2 and 0.075 mg/m2 by swabbing 10 dm2. Chloramphenicol was stable on the plate 2 h before and 24 h after development. Additionally, it was stable during 7 days storage on the cotton swabs in the solvent at room temperature and in diluted standard solution stored in darkness at 4°C. The method can be applied to routine control of pharmaceutical equipment cleanliness by sampling from the stainless steel surface areas of 2.5 to 10 dm2, and an acceptable residue limit of 1 mg/m2.

scholarly journals Study on the effect of Weber Number to heat transfer of multiple droplets on hot stainless steel surface

2018 ◽  
Vol 154 ◽  
pp. 01114 ◽  
Author(s):  
Aria Riswanda ◽  
Indro Pranoto ◽  
Deendarlianto ◽  
Indarto ◽  
Teguh Wibowo
Keyword(s):  
Stainless Steel ◽  
Surface Temperature ◽  
Weber Number ◽  
Steel Surface ◽  
Cooling System ◽  
Spray Cooling ◽  
Stainless Steel Surface ◽  
Temperature Decrease ◽  
Evaporation Time ◽  
Decrease Rate

Multiple droplets are drops of water that continuously dropped onto a surface. Spray cooling is an application of the use of droplet on a cooling system. Spray cooling is usually used in a cooling system of electronic devices, and material quenching. In this study, correlations between Weber number and surface temperature decrease rate during multiple droplets impingement are investigated and analyzed. Visualization process is used to help determine the evaporation time of droplets impingement by using high speed camera. Induction stove is used to maintain a stainless steel surface temperature at 120°C, 140°C, and 160°C. The Weber number was varied at 15, and 52.5 to simulate low and medium Weber number. The result of this study shows that increase in Weber number does not increase the temperature decrease rate noticeably. Whereas the Weber number decrease the time required for surface temperature to reach its lowest surface temperature. It was also found that for low and medium Weber number, Weber number affect the evaporation time of multiple droplets after impingement.

Adhesion characteristics of whole milk powder to a stainless steel surface

1998 ◽  
Vol 97 (3) ◽  
pp. 191-199 ◽  
Author(s):  
Paul R. Rennie ◽  
X.D. Chen ◽  
Antony R. Mackereth
Keyword(s):  
Stainless Steel ◽  
Steel Surface ◽  
Milk Powder ◽  
Stainless Steel Surface ◽  
Whole Milk ◽  
Whole Milk Powder

Tannic acid anchored layer-by-layer covalent deposition of parasin I peptide for antifouling and antimicrobial coatings

RSC Advances ◽  
2016 ◽  
Vol 6 (18) ◽  
pp. 14809-14818 ◽  
Author(s):  
Gang Xu ◽  
Dicky Pranantyo ◽  
Bin Zhang ◽  
Liqun Xu ◽  
Koon-Gee Neoh ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Schiff Base ◽  
Tannic Acid ◽  
Michael Addition ◽  
Steel Surface ◽  
Stainless Steel Surface ◽  
Layer By Layer ◽  
Deposition Technique ◽  
Antimicrobial Coatings ◽  
Layer Deposition

Tannic acid and parasin I were deposited alternatively on stainless steel surface by Michael addition/Schiff base reaction-enabled layer-by-layer deposition technique.

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