Coaggregation occurs amongst bacteria within and between biofilms in domestic showerheads

Abstract

Showerheads support the development multi-species biofilms that can be unsightly, produce malodor, and may harbor pathogens. The outer surface spray plates of many showerheads support visible biofilms that likely contain a mixture of bacteria from freshwater and potentially from human users. Coaggregation, a mechanism by which genetically distinct bacteria specifically recognize one another, may contribute to the retention and enrichment of different species within these biofilms. The aim of this work was to identify the bacterial composition of outer spray plate biofilms of three domestic shower heads and to determine the inter- and intra-biofilm coaggregation ability of each culturable isolate. The bacterial composition of the three biofilms was determined by using bacterial tag-encoded FLX amplicon pyrosequencing (bTEFAP) and by culturing on R2A medium. An average of 31 genera per biofilm were identified using bTEFAP and a total of 30 isolates were cultured. Even though the microbial diversity of each showerhead biofilm differed, every cultured isolate was able to coaggregate with at least one other isolate from the same or different showerhead biofilm. Promiscuous coaggregating isolates belonged to the genera Brevundimonas, Micrococcus, and Lysobacter. This work suggests that coaggregation may be a common feature of showerhead biofilms. Characterization of the mechanisms mediating coaggregation, and the inter-species interactions they facilitate, may allow for novel strategies to inhibit biofilm development.

Microbial Surface Colonization and Biofilm Development in Marine Environments

“…This has been most thoroughly studied in freshwater and wastewater systems and in human oral biofilms to date, although the implications for marine biofilms are clear. Freshwater and wastewater bacteria coaggregate (567,(617)(618)(619), and some freshwater bacteria that can serve as bridging mediators for recruiting different microorganisms to the surface-colonizing microbial community have also been identified (567,(620)(621)(622). Coaggregation of both early and later surface colonizers with the bridging microorganisms contributes to the dynamic changes of species composition and diversity observed in surface-associated microbial communities (567,616,623).…”

Biofilms on Hospital Shower Hoses: Characterization and Implications for Nosocomial Infections

“…Microorganisms forming a biofilm can detach and be transferred to surfaces, medical equipment, and human individuals (13). Biofilms located on hospital showerheads can as such be an important reservoir for nosocomial infections (1,14,15). Previous studies of the microbial community composition of showerhead biofilms have identified nontuberculous mycobacteria (NTM), some of which are considered opportunistic pathogens that are commonly found in natural environments (i.e., soil and water), as well as in the built environment, including hospitals (10,16,17).…”

High-throughput quantitative method for assessing coaggregation among oral bacterial species

“…; Vornhagen et al . ). However, as visual scoring is only semi‐quantitative, it is subject to inconsistency and bias in scoring (Busscher et al .…”

“…Traditionally, coaggregation is assessed using a visual scoring system based on the size of the coaggregates and turbidity of the supernatant fluid (Cisar et al 1979;Gilbert et al 2002;Vornhagen et al 2013). However, as visual scoring is only semi-quantitative, it is subject to inconsistency and bias in scoring (Busscher et al 1995).…”