Evaluating the Antimicrobial Properties of Commercial Hand Sanitizers

ABSTRACT Hand sanitizers have been developed as a convenient means to decontaminate an individual’s hands of bacterial pathogens in situations in which soap and water are not available. Yet to our knowledge, no study has compared the antibacterial efficacy of a large collection of hand sanitizers. Using zone of growth inhibition and kill curve assays, we assessed the performance of 46 commercially available hand sanitizers that were obtained from national chain big-box stores, gasoline stations, pharmacies, and boutiques for antibacterial activity toward prototypical Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacterial pathogens. Results revealed substantial variability in the efficacy of many sanitizers evaluated. Formulations following World Health Organization-recommended ingredients (80% ethanol or 75% isopropyl alcohol) or those including benzalkonium chloride as the active principal ingredient displayed excellent antibacterial activity, whereas others exhibited modest or poor activity in the assays performed. Results also revealed that E. coli was generally more susceptible to most sanitizers in comparison to S. aureus and that there was significant strain-to-strain variability in hand sanitizer antimicrobial efficacy regardless of the organism evaluated. Further, tests of a subset of hand sanitizers toward severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) revealed no direct correlation between antibacterial and antiviral performance, with all ethyl alcohol formulations performing equally well and displaying improved activity in comparison to benzalkonium chloride-containing sanitizer. Taken together, these results indicate that there is likely to be substantial variability in the antimicrobial performance of commercially available hand sanitizers, particularly toward bacterial pathogens, and a need to evaluate the efficacy of sanitizers under development. IMPORTANCE In response to the coronavirus disease 2019 (COVID-19) pandemic, hand hygiene has taken on a prominent role in efforts to mitigate SARS-CoV-2 transmission and infection, which has led to a radical increase in the number and types of hand sanitizers manufactured to meet public demand. To our knowledge, no studies have evaluated or compared the antimicrobial performance of hand sanitizers that are being produced under COVID-19 emergency authorization. Tests of 46 commercially available hand sanitizers purchased from national chain brick-and-mortar stores revealed considerable variability in their antibacterial performance toward two bacterial pathogens of immediate health care concern, S. aureus and E. coli. Expanded testing of a subset of hand sanitizers revealed no direct correlation between antibacterial performance of individual sanitizers and their activity toward SARS-CoV-2. These results indicate that as the pandemic subsides, there will be a need to validate the antimicrobial efficacy of sanitizers being produced.

Download Full-text

Secretion of Anti-Plasmodium Effector Proteins from a Natural Pantoea agglomerans Isolate by Using PelB and HlyA Secretion Signals

Applied and Environmental Microbiology ◽

10.1128/aem.00514-11 ◽

2011 ◽

Vol 77 (13) ◽

pp. 4669-4675 ◽

Cited By ~ 43

Author(s):

Dawn C. Bisi ◽

David J. Lampe

Keyword(s):

Control Strategies ◽

Pectate Lyase ◽

Erwinia Carotovora ◽

Individual Characteristics ◽

Pantoea Agglomerans ◽

Effector Proteins ◽

World Health ◽

Content Type ◽

E Coli ◽

The Individual

ABSTRACTThe insect-vectored disease malaria is a major world health problem. New control strategies are needed to supplement the current use of insecticides and medications. A genetic approach can be used to inhibit development of malaria parasites (Plasmodiumspp.) in the mosquito host. We hypothesized thatPantoea agglomerans, a bacterial symbiont ofAnophelesmosquitoes, could be engineered to express and secrete anti-Plasmodiumeffector proteins, a strategy termed paratransgenesis. To this end, plasmids that include thepelBorhlyAsecretion signals from the genes of related species (pectate lyase fromErwinia carotovoraand hemolysin A fromEscherichia coli, respectively) were created and tested for their efficacy in secreting known anti-Plasmodiumeffector proteins (SM1, anti-Pbs21, and PLA2) inP. agglomeransandE. coli.P. agglomeranssuccessfully secreted HlyA fusions of anti-Pbs21 and PLA2, and these strains are under evaluation for anti-Plasmodiumactivity in infected mosquitoes. Varied expression and/or secretion of the effector proteins was observed, suggesting that the individual characteristics of a particular effector may require empirical testing of several secretion signals. Importantly, those strains that secreted efficiently grew as well as wild-type strains under laboratory conditions and, thus, may be expected to be competitive with the native microbiota in the environment of the mosquito midgut.

Download Full-text

F Plasmids Are the Major Carriers of Antibiotic Resistance Genes in Human-Associated Commensal Escherichia coli

mSphere ◽

10.1128/msphere.00709-20 ◽

2020 ◽

Vol 5 (4) ◽

Author(s):

Craig Stephens ◽

Tyler Arismendi ◽

Megan Wright ◽

Austin Hartman ◽

Andres Gonzalez ◽

...

Keyword(s):

Escherichia Coli ◽

Antibiotic Resistance ◽

Transposable Elements ◽

Dna Sequencing ◽

Resistance Genes ◽

Bacterial Pathogens ◽

Acquired Resistance ◽

Antibiotic Resistance Genes ◽

Content Type ◽

E Coli

ABSTRACT The evolution and propagation of antibiotic resistance by bacterial pathogens are significant threats to global public health. Contemporary DNA sequencing tools were applied here to gain insight into carriage of antibiotic resistance genes in Escherichia coli, a ubiquitous commensal bacterium in the gut microbiome in humans and many animals, and a common pathogen. Draft genome sequences generated for a collection of 101 E. coli strains isolated from healthy undergraduate students showed that horizontally acquired antibiotic resistance genes accounted for most resistance phenotypes, the primary exception being resistance to quinolones due to chromosomal mutations. A subset of 29 diverse isolates carrying acquired resistance genes and 21 control isolates lacking such genes were further subjected to long-read DNA sequencing to enable complete or nearly complete genome assembly. Acquired resistance genes primarily resided on F plasmids (101/153 [67%]), with smaller numbers on chromosomes (30/153 [20%]), IncI complex plasmids (15/153 [10%]), and small mobilizable plasmids (5/153 [3%]). Nearly all resistance genes were found in the context of known transposable elements. Very few structurally conserved plasmids with antibiotic resistance genes were identified, with the exception of an ∼90-kb F plasmid in sequence type 1193 (ST1193) isolates that appears to serve as a platform for resistance genes and may have virulence-related functions as well. Carriage of antibiotic resistance genes on transposable elements and mobile plasmids in commensal E. coli renders the resistome highly dynamic. IMPORTANCE Rising antibiotic resistance in human-associated bacterial pathogens is a serious threat to our ability to treat many infectious diseases. It is critical to understand how acquired resistance genes move in and through bacteria associated with humans, particularly for species such as Escherichia coli that are very common in the human gut but can also be dangerous pathogens. This work combined two distinct DNA sequencing approaches to allow us to explore the genomes of E. coli from college students to show that the antibiotic resistance genes these bacteria have acquired are usually carried on a specific type of plasmid that is naturally transferrable to other E. coli, and likely to other related bacteria.

Download Full-text

Electrospun Active Biopapers of Food Waste Derived Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) with Short-Term and Long-Term Antimicrobial Performance

Nanomaterials ◽

10.3390/nano10030506 ◽

2020 ◽

Vol 10 (3) ◽

pp. 506 ◽

Cited By ~ 5

Author(s):

Kelly J. Figueroa-Lopez ◽

Sergio Torres-Giner ◽

Daniela Enescu ◽

Luis Cabedo ◽

Miguel A. Cerqueira ◽

...

Keyword(s):

Antimicrobial Activity ◽

Antimicrobial Properties ◽

High Antimicrobial Activity ◽

Short Term ◽

Oregano Essential Oil ◽

E Coli ◽

Closed Systems ◽

Antimicrobial Performance ◽

And Migration

This research reports about the development by electrospinning of fiber-based films made of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) derived from fermented fruit waste, so-called bio-papers, with enhanced antimicrobial performance. To this end, different combinations of oregano essential oil (OEO) and zinc oxide nanoparticles (ZnONPs) were added to PHBV solutions and electrospun into mats that were, thereafter, converted into homogeneous and continuous films of ~130 μm. The morphology, optical, thermal, mechanical properties, crystallinity, and migration into food simulants of the resultant PHBV-based bio-papers were evaluated and their antimicrobial properties were assessed against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) in both open and closed systems. It was observed that the antimicrobial activity decreased after 15 days due to the release of the volatile compounds, whereas the bio-papers filled with ZnONPs showed high antimicrobial activity for up to 48 days. The electrospun PHBV biopapers containing 2.5 wt% OEO + 2.25 wt% ZnONPs successfully provided the most optimal activity for short and long periods against both bacteria.

Download Full-text

Antimicrobial Properties of a Chitosan Dextran-Based Hydrogel for Surgical Use

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.05463-11 ◽

2011 ◽

Vol 56 (1) ◽

pp. 280-287 ◽

Cited By ~ 80

Author(s):

Manal A. Aziz ◽

Jaydee D. Cabral ◽

Heather J. L. Brooks ◽

Stephen C. Moratti ◽

Lyall R. Hanton

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

Bacterial Species ◽

Antimicrobial Properties ◽

Sinus Surgery ◽

Peptide Bonds ◽

Content Type ◽

E Coli ◽

Transmission Electron

ABSTRACTA chitosan dextran-based (CD) hydrogel, developed for use in endoscopic sinus surgery, was tested for antimicrobial activityin vitroagainst a range of pathogenic microorganisms. The microdilution technique was used to determine minimum inhibitory, minimum bactericidal, and minimum fungicidal concentrations. In addition, the time-kill efficacy of CD hydrogel was determined for two bacterial species. Scanning and transmission electron microscopy were carried out to elucidate the antimicrobial mechanism of this compound. CD hydrogel was found to be effective againstStaphylococcus aureus,Streptococcus pyogenes,Escherichia coli, andClostridium perfringensat its surgical concentration of 50,000 mg/liter. Minimum bactericidal concentrations ranged from 2,000 to 50,000 mg/liter. Dextran aldehyde (DA) was found to be the antimicrobial component of the CD hydrogel with MBC ranging from 2,000 to 32,000 mg/liter.S. aureusappeared to be killed at a slightly faster rate thanE. coli. Candida albicansandPseudomonas aeruginosawere more resistant to CD hydrogel and DA. Scanning and transmission electron microscopy ofE. coliandS. aureusincubated with CD hydrogel and DA alone revealed morphological damage, disrupted cell walls, and loss of cytosolic contents, compatible with the proposed mode of action involving binding to cell wall proteins and disruption of peptide bonds. Motility and chemotaxis tests showedE. colito be inhibited when incubated with DA. The antibacterial activity of CD hydrogel may make it a useful postsurgical aid at other body sites, especially where there is a risk of Gram-positive infections.

Download Full-text

Hypoxia-Mediated Impairment of the Mitochondrial Respiratory Chain Inhibits the Bactericidal Activity of Macrophages

Infection and Immunity ◽

10.1128/iai.05972-11 ◽

2012 ◽

Vol 80 (4) ◽

pp. 1455-1466 ◽

Cited By ~ 27

Author(s):

Melanie Wiese ◽

Roman G. Gerlach ◽

Isabel Popp ◽

Jasmin Matuszak ◽

Mousumi Mahapatro ◽

...

Keyword(s):

Antibacterial Activity ◽

Respiratory Chain ◽

Bactericidal Activity ◽

Mitochondrial Respiratory Chain ◽

Host Cells ◽

Mitochondrial Activity ◽

Oxygen Intermediates ◽

Content Type ◽

E Coli ◽

Mitochondrial Respiratory

ABSTRACTIn infected tissues oxygen tensions are low. As innate immune cells have to operate under these conditions, we analyzed the ability of macrophages (Mϕ) to killEscherichia coliorStaphylococcus aureusin a hypoxic microenvironment. Oxygen restriction did not promote intracellular bacterial growth but did impair the bactericidal activity of the host cells against both pathogens. This correlated with a decreased production of reactive oxygen intermediates (ROI) and reactive nitrogen intermediates. Experiments with phagocyte NADPH oxidase (PHOX) and inducible NO synthase (NOS2) double-deficient Mϕ revealed that inE. coli- orS. aureus-infected cells the reduced antibacterial activity during hypoxia was either entirely or partially independent of the diminished PHOX and NOS2 activity. Hypoxia impaired the mitochondrial activity of infected Mϕ. Inhibition of the mitochondrial respiratory chain activity during normoxia (using rotenone or antimycin A) completely or partially mimicked the defective antibacterial activity observed in hypoxicE. coli- orS. aureus-infected wild-type Mϕ, respectively. Accordingly, inhibition of the respiratory chain ofS. aureus-infected, normoxic PHOX−/−NOS2−/−Mϕ further raised the bacterial burden of the cells, which reached the level measured in hypoxic PHOX−/−NOS2−/−Mϕ cultures. Our data demonstrate that the reduced killing ofS. aureusorE. coliduring hypoxia is not simply due to a lack of PHOX and NOS2 activity but partially or completely results from an impaired mitochondrial antibacterial effector function. Since pharmacological inhibition of the respiratory chain raised the generation of ROI but nevertheless phenocopied the effect of hypoxia, ROI can be excluded as the mechanism underlying the antimicrobial activity of mitochondria.

Download Full-text

Hydrothermal Fabrication of Spindle-Shaped ZnO/Palygorskite Nanocomposites Using Nonionic Surfactant for Enhancement of Antibacterial Activity

Nanomaterials ◽

10.3390/nano9101453 ◽

2019 ◽

Vol 9 (10) ◽

pp. 1453 ◽

Cited By ~ 2

Author(s):

Aiping Hui ◽

Shuqing Dong ◽

Yuru Kang ◽

Yanmin Zhou ◽

Aiqin Wang

Keyword(s):

Escherichia Coli ◽

Staphylococcus Aureus ◽

Antibacterial Activity ◽

Low Cost ◽

Ionic Surfactants ◽

E Coli ◽

Antibacterial Performance ◽

Good Antibacterial Activity ◽

Controllable Growth ◽

And Staphylococcus Aureus

In order to improve the antibacterial performance of natural palygorskite, spindle-like ZnO/palygorskite (ZnO/PAL) nanocomposites with controllable growth of ZnO on the surface of PAL were prepared in the presence of non-ionic surfactants using an easy-to-operate hydrothermal method. The obtained ZnO/PAL nanocomposites have a novel and special spindle-shaped structure and good antibacterial activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), and are also low cost. The minimum inhibitory concentrations of ZnO/PAL nanocomposites toward E. coli and S. aureus reached 1.5 and 5 mg/mL, respectively.

Download Full-text

Synthesis, Characterization and Evaluation of Antimicrobial Properties of (R)-(-)-4-Phenyl-2 Oxazolidinone Based Azetidinones

Anti-Infective Agents ◽

10.2174/2211352516666180619153317 ◽

2018 ◽

Vol 16 (2) ◽

pp. 104-113 ◽

Cited By ~ 1

Author(s):

Shyamal Baruah ◽

Amrit Puzari ◽

Farhana Sultana ◽

Jayanta Barman

Keyword(s):

Escherichia Coli ◽

Antibacterial Activity ◽

Acetic Acid ◽

Bacillus Subtilis ◽

Antibacterial Property ◽

Antimicrobial Properties ◽

Side Chain ◽

Alkyl Side Chain ◽

E Coli ◽

Aromatic Imines

Introduction: A series of (R)-(-)-4-Phenyl-2 oxazolidinone based azetidinones (4a-i) were synthesized from the reaction of (2-Oxo-4-phenyl-oxazolidin-3-yl) acetic acid with aromatic imines (3a-i) in the presence of Thionyl chloride and Triethylamine as a base. Methods: The transformation proceeds through the formation of acid chloride to ketene which finally forms the azetidinones through [2+2] cycloaddition with aromatic imines. Products obtained were screened to evaluate their antibacterial activity with respect to known bacteria like Escherichia Coli (E. Coli) and Bacillus subtilis. Results and Conclusion: In most of the cases, azetidinones were found to exhibit superior antimicrobial properties than oxazolidinones. They were found to be a good inhibitor of gram-positive and gramnegative bacteria. Enhancement of antibacterial property can be attributed to the presence of azetidinone ring and hydrophobic alkyl side chain in the scaffolds.

Download Full-text

Acute Limonene Toxicity in Escherichia coli Is Caused by Limonene Hydroperoxide and Alleviated by a Point Mutation in Alkyl Hydroperoxidase AhpC

Applied and Environmental Microbiology ◽

10.1128/aem.01102-15 ◽

2015 ◽

Vol 81 (14) ◽

pp. 4690-4696 ◽

Cited By ~ 40

Author(s):

Victor Chubukov ◽

Florence Mingardon ◽

Wendy Schackwitz ◽

Edward E. K. Baidoo ◽

Jorge Alonso-Gutierrez ◽

...

Keyword(s):

Escherichia Coli ◽

Antimicrobial Properties ◽

Wild Type ◽

Food Preservative ◽

Citrus Peel ◽

Content Type ◽

E Coli ◽

The Common ◽

Alkyl Hydroperoxidase ◽

Peel Oil

ABSTRACTLimonene, a major component of citrus peel oil, has a number of applications related to microbiology. The antimicrobial properties of limonene make it a popular disinfectant and food preservative, while its potential as a biofuel component has made it the target of renewable production efforts through microbial metabolic engineering. For both applications, an understanding of microbial sensitivity or tolerance to limonene is crucial, but the mechanism of limonene toxicity remains enigmatic. In this study, we characterized a limonene-tolerant strain ofEscherichia coliand found a mutation inahpC, encoding alkyl hydroperoxidase, which alleviated limonene toxicity. We show that the acute toxicity previously attributed to limonene is largely due to the common oxidation product limonene hydroperoxide, which forms spontaneously in aerobic environments. The mutant AhpC protein with an L-to-Q change at position 177 (AhpCL177Q) was able to alleviate this toxicity by reducing the hydroperoxide to a more benign compound. We show that the degree of limonene toxicity is a function of its oxidation level and that nonoxidized limonene has relatively little toxicity to wild-typeE. colicells. Our results have implications for both the renewable production of limonene and the applications of limonene as an antimicrobial.

Download Full-text

Critical Synergistic Concentration of Lecithin Phospholipids Improves the Antimicrobial Activity of Eugenol against Escherichia coli

Applied and Environmental Microbiology ◽

10.1128/aem.01583-17 ◽

2017 ◽

Vol 83 (21) ◽

Cited By ~ 2

Author(s):

Haoshu Zhang ◽

Edward G. Dudley ◽

Federico Harte

Keyword(s):

Escherichia Coli ◽

Foodborne Pathogens ◽

Rational Design ◽

Microbial Population ◽

Critical Concentration ◽

Antimicrobial Properties ◽

Content Type ◽

E Coli ◽

Log Reduction ◽

Naturally Occurring

ABSTRACT In this study, the effect of individual lecithin phospholipids on the antimicrobial properties of eugenol against Escherichia coli C600 was investigated. We tested five major phospholipids common in soy or egg lecithin (1,2-dihexadecanoyl-sn-glycero-3-phosphocholine [DPPC], 1,2-dioctadecanoyl-sn-glycero-3-phosphocholine [DSPC], 1,2-dihexadecanoyl-sn-glycero-3-phosphoethanolamine [DPPE], 1,2-dihexadecanoyl-sn-glycero-3-phosphate [sodium salt] [DPPA], and 1,2-dihexadecanoyl-sn-glycero-3-phospho-l-serine [DPPS]) and one synthetic cationic phospholipid (1,2-dioctadecanoyl-sn-glycero-3-ethylphosphocholine [18:0 EPC]). Among the six phospholipids, DPPC, DSPC, DPPE, DPPA, and the cationic 18:0 EPC showed critical synergistic concentrations that significantly improved the inactivation effect of eugenol against E. coli after 30 min of exposure. At the critical synergistic concentration, an additional ca. 0.4 to 1.9 log reduction (ca. 0.66 to 2.17 log CFU/ml reduction) in the microbial population was observed compared to eugenol-only (control) treatments (ca. 0.25 log reduction). In all cases, increasing the phospholipid amount above the critical synergistic concentration (which was different for each phospholipid) resulted in antimicrobial properties similar to those seen with the eugenol-only (control) treatments. DPPS did not affect the antimicrobial properties of eugenol at the tested concentrations. The critical synergistic concentration of phospholipids was correlated with their critical micelle concentrations (CMC). IMPORTANCE Essential oils (EOs) are naturally occurring antimicrobials, with limited use in food due to their hydrophobicity and strong aroma. Lecithin is used as a natural emulsifier to stabilize EOs in aqueous systems. We previously demonstrated that, within a narrow critical-concentration window, lecithin can synergistically enhance the antimicrobial properties of eugenol. Since lecithin is a mixture of different phospholipids, we aimed to identify which phospholipids are crucial for the observed synergistic effect. This research studied the bioactivity of lecithin phospholipids, contributing to a rational design in using lecithin to effectively control foodborne pathogens in foods.

Download Full-text

Decay of Bacterial Pathogens, Fecal Indicators, and Real-Time Quantitative PCR Genetic Markers in Manure-Amended Soils

Applied and Environmental Microbiology ◽

10.1128/aem.02427-10 ◽

2011 ◽

Vol 77 (14) ◽

pp. 4839-4848 ◽

Cited By ~ 70

Author(s):

Shane W. Rogers ◽

Matthew Donnelly ◽

Lindsay Peed ◽

Catherine A. Kelty ◽

Sumona Mondal ◽

...

Keyword(s):

Genetic Markers ◽

Fluorescent Protein ◽

Bacterial Pathogens ◽

Rate Coefficients ◽

Content Type ◽

E Coli ◽

First Order ◽

Real Time Quantitative Pcr ◽

Serovar Typhimurium ◽

Contamination Events

ABSTRACTThis study examined persistence and decay of bacterial pathogens, fecal indicator bacteria (FIB), and emerging real-time quantitative PCR (qPCR) genetic markers for rapid detection of fecal pollution in manure-amended agricultural soils. Known concentrations of transformed green fluorescent protein-expressingEscherichia coliO157:H7/pZs and red fluorescent protein-expressingSalmonella entericaserovar Typhimurium/pDs were added to laboratory-scale manure-amended soil microcosms with moisture contents of 60% or 80% field capacity and incubated at temperatures of −20°C, 10°C, or 25°C for 120 days. A two-stage first-order decay model was used to determine stage 1 and stage 2 first-order decay rate coefficients and transition times for each organism and qPCR genetic marker in each treatment. Genetic markers for FIB (Enterococcusspp.,E. coli, andBacteroidales) exhibited decay rate coefficients similar to that ofE. coliO157:H7/pZs but not ofS. entericaserovar Typhimurium/pDs and persisted at detectable levels longer than both pathogens. Concentrations of these two bacterial pathogens, their counterpart qPCR genetic markers (stx1andttrRSBCA, respectively), and FIB genetic markers were also correlated (r= 0.528 to 0.745). This suggests that these qPCR genetic markers may be reliable conservative surrogates for monitoring fecal pollution from manure-amended land. Host-associated qPCR genetic markers for microbial source tracking decayed rapidly to nondetectable concentrations, long before FIB,Salmonella entericaserovar Typhimurium/pDs, andE. coliO157:H7/pZs. Although good indicators of point source or recent nonpoint source fecal contamination events, these host-associated qPCR genetic markers may not be reliable indicators of nonpoint source fecal contamination events that occur weeks following manure application on land.

Download Full-text