Urban informal settlements as hotspots of antimicrobial resistance and the need to curb environmental transmission

Abstract

Antimicrobial resistance is a growing public health challenge that is expected to disproportionately burden lower-and middle-income countries (LMICs) in the coming decades. Although the contributions of human and veterinary antibiotic misuse to this crisis are well-recognized, environmental transmission (via water, soil, or food contaminated with human and animal feces) has been given less attention as a global driver of antimicrobial resistance (AMR), especially in urban informal settlements in LMICs, commonly known as "shantytowns" or "slums." These settlements may be unique hotspots for environmental AMR transmission given: 1) the high density of humans, livestock, and vermin living in close proximity; 2) frequent antibiotic misuse; and 3) insufficient drinking water, drainage, and sanitation infrastructure. Here, we highlight the need for strategies to disrupt environmental AMR transmission in urban informal settlements. We propose that water and waste infrastructure improvements tailored to these settings should be evaluated for their effectiveness in limiting environmental AMR dissemination, lowering the community-level burden of antimicrobial-resistant infections, and preventing antibiotic misuse. We also suggest that additional research is directed towards developing economic and legal incentives for evaluating and implementing water and waste infrastructure in these settings. Given that almost 90% of urban population growth will occur in regions predicted to be most burdened by the AMR crisis, there is an urgent need to build effective, evidence-based policies that could influence massive investments in the built urban environment in LMICs over the next few decades. Urban informal settlements are densely populated residential areas characterized by insufficient access to improved water and sanitation services, households constructed of non-durable material, insufficient living area, insecure residential status, and high participation in the informal economy 1-3. Four of the five largest slums in the world are in Asian and African LMICs, and in some countries, over 50% of the urban population resides in these types of settlements (e.g., Bangladesh, Kenya, Ethiopia) 1. Population densities are difficult to measure in urban informal settlements but they are estimated to exceed 125,000 persons/square km in multiple major LMIC cities, including Hyderabad

Market Chickens as a Source of Antibiotic-Resistant Escherichia coli in a Peri-Urban Community in Lima, Peru

“…The effect may be exacerbated in this community, where water and adequate sanitation are not available in all households. Surveys collected during an ongoing cohort study in VES (unpublished data) indicate that the most commonly used antibiotics in this group were amoxicillin and amoxicillin with clavulanic acid, followed by trimethoprim/sulfamethoxazole and erythromycin, consumed between the first 2 months up to 2 years at a rate of 3.8 courses per child-year (Nadimpalli et al, 2020). Predictably, 63.9% of the baby isolates in our study exhibited resistance to amoxicillin and 52.5% to trimethoprim/sulfamethoxazole.…”

“…These neighboring districts share similar demographic characteristics and contain various urban informal settlements (Instituto Nacional de Estadística e Informática [INEI], 2017). Informal housing arrangements, lack of running water, and inadequate sanitation in most households make these sites representative of peri-urban settlements in other LMICs, which are considered hotspots for AMR (Nadimpalli et al, 2020). We also collected laying hens' samples from an organic free-range farm in Vegueta (VEG), located approximately 150 km north of Lima.…”

Computational Model to Quantify the Growth of Antibiotic Resistant Bacteria in Wastewater

“…Wastewater and sewage systems are a major reservoir of resistant bacterial populations due to the collection of antibiotic waste from humans and animals, inappropriate drug disposal, and effluent from drug manufacturers, hospitals and agricultural/veterinary settings (1). In some cases, environmental concentrations can reach, or even exceed, minimal inhibitory concentrations of certain antibiotics (2).…”

Review of therapeutic options for infections with carbapenem-resistant Klebsiella pneumoniae

“…In 2018, for instance, in some European countries such as Greece, Romania and Italy 63.9, 29.5 and 26.8% of clinical enterobacterial isolates have been tested resistant against carbapenems, respectively [ 14 ]. Notably, in low- and middle-income countries the prevalence rates in carbapenem resistance have been even more progressively rising [ 15 , 16 ] posing a more pronounced threat to infected patients given that individuals are more prone to severe infection due their poorer living conditions, fewer treatment options and higher abundances of immunosuppressive co-morbidities [ 17 , 18 ].…”