Total Bacterial Counts: Figure 2 displays the relative densities of total heterotrophic plate counts recovered from various wristbands. Viable bacteria varied widely between subjects and even wristbands made of the same materials. On the average however, the trend of bacteria load was cloth ≥ plastic ≥ rubber ≥ leather > metal. The lowest total bacterial counts were from a metal (gold) wristband, with 0 cfu/cm².

Staphylococcal Bacterial Counts: Figure 3(a) displays the occurrence of viable staphylococcal plate counts for the wristbands. No significant differences (P = 0.05) were noted on the average because of high variability of staph counts between subjects and within wristband materials; except for the metallic bands

which recorded significantly lower levels of bacteria. The value of the leather wristband relies on a single subject, and so may not be representative. Mannitol-fermenting staphylococci, such as S. aureus, were identified on plates as distinctly yellow colonies (Figure 3(b)) and confirmed microscopically after catalase +ve test.

Bacterial Counts: No viable Pseudomonas bacteria were identified from any of the cloth, leather, and metal wristbands except for Subject 8 metallic band. The average log cfu for rubber bands and plastic were similar (Figure 4). Most wristbands did not appear to have cultivable Pseudomonas, with only six samples (three rubber, two plastic, and one metal) out of 20 showing growth on the selective-differential agar.

Enteric Bacterial Counts: Gram negative, oxidase negative lactose fermenting rods on the MacConkey agar assays showed highly elevated levels of enteric bacteria obtained for Subject 19 (26,760 cfu/cm²), a veterinary assistant wearing a rough rubber wristband and for subject #12, a firefighter’s plastic wristband (Figure 5). Several samples (eight of the twenty) did not contain any enteric

bacteria. Wristbands made of rubber, plastic and to a lesser extent, metals harbored the most enteric organisms.

Overall Microbiology of the Wristband: Figure 6 presents the relative density of various bacteria assayed and the total heterotrophic counts in the context of gender and wristband matrix and gender of the subjects. Total heterotrophic bacteria counts associated with wristbands on male subjects (N = 12) were higher (4.045 log₁₀ cfu/cm²) than that of females (N = 8) at 3.422. There were no significant gender differences in the distribution and occurrence of the bacteria groups.

Bacteria identified in the initial study were Staphylococci and Pseudomonads and Enterobacteriaceae (enteric bacteria). Staphylococcal bacteria likely included Staphylococcus epidermidis, a common resident of the skin, identified through the MSA assay, microscopy and catalase. S. epidermidis is a member of the commensal or mutualistic microbiota of humans. It prevents colonization by dangerous related pathogenic bacteria. S. epidermidis induces host production of antimicrobial proteins (AMPs), which selectively act against harmful bacteria

like S. aureus [10] . However, S. epidermidis also acts as a significant opportunistic pathogen, frequently spread through the use of medical indwelling devices [11] . In the United States alone it is estimated that $2 billion is spent annually on blood-related S. epidermidis infections [12] . S. aureus, which was found on Sample 17, can pose a significant threat to human health under certain conditions. S. aureus has been shown to infect the cardiovascular system where its coagulase enzyme leads to blood-clotting issues, causing infective endocarditis or thrombophlebitis and, eventually, organ failure and death [13] . The highest staphylococcal bacterial counts were found on the plastic wristbands, followed by cloth, rubber, and leather which are common band materials.

Pseudomonas species, including P. aeruginosa, is a common skin resident, Gram-negative, aerobic bacteria. P. aeruginosa also acts as an opportunistic pathogen, targeting cancer and cystic fibrosis patients, invading burnt tissues, and causing a variety of health complications, including urinary tract infections (UTIs) [14] . This is due to its production of leucocidins which reduces polymorphonuclear leukocyte (PMNs) and other virulent factors [15] . P. aeruginosa was identified on the plastic and rubber wristbands, but not on the cloth, metal, and leather materials.

The family Enterobacteriaceae, specifically the genera Enterobacter, Klebsiella and Escherichia, consist of gram-negative, facultative bacteria found in the intestines, but have been reported to cause health problems in extraintestinal environments [16] . Enterobacteriaceae appeared on the Mac assay as pink, mucoid colonies. The findings included the identification of Escherichia coli, which most commonly begins infection through fecal-oral transmission. E. coli can also cause health problems including gastroenteritis and UTIs [17] . Klebsiella infections may also pose health concerns, including pneumonia and UTIs [14] . Our results found the highest counts of these bacteria on the rubber and plastic wristbands.

In our study, wristbands were obtained from 12 males and 8 females. Although this sample size is not large enough to draw definitive conclusions, trends indicated greater cfu/person for wristbands from women: 267,470 vs 72,622 for males. However, this data is strongly skewed by Subject 19 (possibly contaminated by animal products), which showed a count almost four times larger than the next highest, Subject 15. When this outlier is excluded, the overall trend for total heterotrophic cfu/person was lower for females than males (Figure 6).

In terms of activity, 7 subjects were working at a news station, 6 were firefighters, 4 were at the gym, and 3 were working with animals at a veterinary office. The largest counts of fecal bacteria (such as E. coli) and total bacteria were observed from Subject 19, a veterinarian’s wristband, while the largest count of Pseudomonas bacteria was observed on Subject 17, who was at the gym. Interestingly, the wristband from Subject 17 also displayed signs of S. aureus. Subject 15, another gym-goer, showed the highest staphylococcal counts. These results emphasize the necessity of wristband sanitation after working with animals or engaging in rigorous activity at the gym or at home.

Samples were obtained from rubber, plastic, metal, cloth, and leather wristbands. The highest total counts were found on rubber and plastic wristbands, while the lowest was from metal and rubber wristbands. Plastic and rubber wristbands may provide a more appropriate environment for bacterial growth; many plastics have been shown to act as substrates for S. aureus, S. epidermidis, P. aeruginosa, and E. coli [18] . Porous and static surfaces tend to attract and be colonized by bacteria.

Metal wristbands overall did not show high bacterial counts; the lowest was from Sample 3, a gold wristband, with 0 cfu/cm². This material’s anti-bacterial properties may come from its ability to create nanocages that fragment bacterial DNA and perforate membranes, thus inactivating bacteria [19] . Conversely, S. epidermidis shows enhanced bio-adhesion on stainless steel than on a biological skin model substrate, although S. aureus showed the opposite result [20] . Several studies [21] [22] [23] have shown that the material composition of a surface determines its wettability and surface tension, affecting the potency of different disinfectants. Bacteria adhesion to surfaces varies greatly between strains and gram reactions of species; and directly affects the efficacy of disinfection [21] . Adhesion is determined by surface roughness, hydrophobicity and surface free energy. Previous studies [22] have reported a positive correlation between surface hydrophobicity (surface wettability) and adhesion of Staphylococcus aureus and epidermidis. Tight adhesion to hydrophobic surface could explain the longer exposure time needed to inactivate bacteria on plastic wristbands (Figure 7) as well as the relatively high prevalence of commensals on rubber and plastic wristbands which are synthetic hydrophobic polymers.

Disinfectants employed in the follow-up study on the plastic wristband reduced bacterial counts to 0 after two minutes of application which is within prescribed exposure recommendations.

Lysol Disinfectant Spray, 70% Ethanol, and Heinz Apple Cider Vinegar were tested on the wristbands of different materials. PBS was used as a control because it lacks antimicrobial properties and prevents osmotic lysis unrelated to chemical disinfectants. All disinfectants tested reduced bacterial counts to 0 cfu/mL within 30 seconds for cloth and rubber wristbands, whereas a full 2-minute exposure was required for apple cider vinegar (ACV) to reduce bacterial counts to 0 cfu/mL on the plastic wristbands. The similar trends of Lysol Disinfectant Spray and 70% ethanol in this study may be because the most significant active ingredient in Lysol Disinfectant Spray is also 79% ethanol plus other reducing agents. They inactivate bacteria by dissolving the membrane, disrupting cellular respiration and denaturing proteins. Apple cider vinegar showed different trends, generally as being less effective in this study and on the surfaces examined. ACV is also known to disrupt the cell membrane integrity, metabolism, and nuclear material of E. coli and S. aureus (Yagnik et al., 2018) [4] and can inhibit the growth of antibiotic strains of bacteria, such as MRSA [24] . Notwithstanding the outcome of any disinfection exercise is a product of the strain, surface physiochemical attributes, bacteria density and biofilm state of the organisms.

The recommended usage time for Lysol Disinfectant Spray is 5 minutes for the bacteria we identified, and the United States Center for Disease Control (CDC) found that 70% ethanol is effective against P. aeruginosa, E. coli, and S. aureus after 10 seconds [25] .

The COVID-19 pandemic places special emphasis on regular sanitation and disinfecting of surfaces that come into contact with body mucous membranes (i.e., eyes, nose, and mouth). Oftentimes, basic sanitization and disinfection of surfaces are not practiced as a result of perceived difficulties and ignorance of their processes; most notably, types of disinfectants that may be used, cost of disinfectants, recommended usage times, and concerns over chemicals involved in popular disinfectants. Common household disinfectants, which can be obtained easily at low costs, include Lysol Disinfectant Spray, 70% ethanol, and ACV. ACV was chosen in this study due to its reputation as a natural or organic disinfectant. Our results indicate that these household disinfectants, even at usage times below their recommended, have significant disinfecting properties. The recommended usage times of disinfectants are still advised.

As these results indicate some sanitary effect for all three disinfectants for the two-minute periods on all four materials, their use may contribute significantly to COVID-19 and other communicable disease safety measures. Other potential forms of bacterial transmission and facilitation of infection, such as earbuds or cell phones, should be similarly studied. A special emphasis on this method of study in relation to healthcare workers and hospital environments should also be pursued, as many of these bacteria pose significant threats to the health of immunocompromised patients. Although the disinfectants showed maximum potency after 2 minutes, increasing the exposure time during personal hygiene is recommended.