Assessment of Microbial Behavior in Incontinence Products using a Laboratory Scale Model

Abstract

Urinary Incontinence is a problem for many people which can give rise to both psychological and social issues. To their aid there are a range of incontinence products available in retail today. A customer concern is however possible malodor formation. Studies have shown that both urine and the bacterial flora can contribute to malodor but the impact of microbial behavior in incontinence products on possible malodor formation has not yet been explored. Incontinence products consist of cellulosic fibers and partly neutralized super-absorbent polymers (SAP) which may influence microbial growth and metabolism. The behavior of Escherichia coli and Staphylococcus epidermidis, in incontinence product and SAP, has been investigated using flow cytometry, viable count, HPLC and microcalorimetry. Localization of bacteria in product was also explored using confocal microcopy.
The results showed that the growth rate in product saturated to 50% (5x the weight of the product) with urine was 0.45 ± 0.05 for E. coli and 0.018 ± 0.04 for S. epidermidis. The product furthermore always buffered the environment to around pH 6.2 for both bacterial species and irrespective of saturation level. The percentage of damaged/dead cells was low during the first 3-6 h followed by an increase at 22 h of incubation at 35°C. A significant difference between the saturation levels for both species was observed where 5x saturation showed lower growth and survival compared to 10x saturation. On superabsorbent polymers (SAP) alone, one of the components of the product, the microbial activity was found to be higher for E. coli than S. epidermidis. The growth rate was higher for E. coli on SAP compared to in product and considerably lower for S. epidermidis. Confocal microscopy revealed that the majority of bacteria were localized on the surface of cellulosic fiber and SAP .
In conclusion; initial pH did not impact bacterial growth; both bacteria showed capacity to grow in this environment and also remained alive in the product for at least one day. Furthermore the level of liquid saturation of the product had an impact on bacterial survival over time indicating that this in an important factor to consider when studying metabolic activity and survival of cells in product.

Popular Abstract (Swedish)

Lukten av urin kan nog många känna igen men för vissa, de som använder sig av inkontinensskydd, kan det vara kopplat till en oro att det kommer från en själv. Bakterier som vi har naturligt på kroppen kan ha en roll i möjlig luktutveckling när man använder sig av inkontinensskydd. Frågan är då om och i sådana fall hur denna lukt utvecklas från bakterier i inkontinensskydd? För att ta reda på det så behöver man veta hur bakterierna beter sig i miljön som uppstår av urin i inkontinensskydd. Överlever de? Växer de? Vilka ämnen tillverkas av bakterierna? För att besvara dessa frågor har beteendet av de två olika bakterierna Escherichia coli och Staphylococcus epidermidis, undersökts.

• author: Sundström, Astrid
• supervisor: Jenny Schelin; Sebastian Jankowski
• organization: Applied Microbiology; Biotechnology
• course: KMB820 20171
• year: 2017
• type: H2 - Master's Degree (Two Years)
• subject: Technology and Engineering
• keywords: Staphylococcus epidermidis, Escherichia coli, urinary incontinence, applied microbiology, microbial behavior, teknisk mikrobiologi
• language: English
• id: 8922294
• date added to LUP: 2017-08-18 09:30:34
• date last changed: 2017-08-18 09:30:34