Probiotic urbanisation and the genealogies of filth

The relationships between ‘filth’, microbial ecologies, and the urban environment are complex and dynamic. In Global North contexts, nineteenth century epidemics caused by pathogenic microorganisms forced major political and infrastructural urban reorganisation. More recent scientific and sociocultural imaginaries of microbial exposure and curated forms of ‘filth’ as positive for human health, i.e., probiotic (govern)mentalities, are finding their way into the conceptualisation and governance of urban environments. This groundwork paves the way for expanded accounts of urban human-microbial relationality and co-evolution, including the consideration of extracorporeal and distributed urban microbiomes and their interactions with both ‘bacteriological’ and ‘probiotic’ renderings of urbanity. Firstly, the technological success of the bacteriological city was underpinned by the generation of a set of highly productive microbial ecologies that protected public health, namely those involved in the treatment of drinking water and wastewater. These early efforts at putting bacteria to work suggest the co-existence of various imaginaries of microbes - as ‘good’ and ‘bad’ - at the turn of the twentieth century. Secondly, these foundations open the door for the excavation of alternative genealogies of human-microbial-urban dynamics, including those from the Global South, the Global East, and the role of interactions in deep time. Finally, the lessons of antimicrobial resistance further complicate contemporary celebrations of ‘good bacteria.’ The analytical framework of probiotic blowback may be useful for charting the material trajectories and possible futures of socio-microbial relationality across space and time.