Hospital wastewater effluent: hot spot for antibiotic resistant bacteria

Abstract

<jats:title>Abstract</jats:title> <jats:p>Hospital wastewaters are highly complex effluents acting as a hotspot for antibiotic resistant bacteria. Especially, Gram-negative bacteria bearing multiple antibiotic resistant genes are increasingly found in hospital wastewaters. The aim of this study was to evaluate the presence of extended spectrum beta-lactamases (ESBL) and carbapenemase producing Enterobacteriaceae in hospital wastewaters from one Slovenian and two Austrian hospitals, as well as the occurrence of antibiotic resistant genes encoding for VIM, KPC, NDM, CTXM and OXA beta-lactamases in isolates from hospital wastewater. The results indicated high levels of ESBL producing Enterobacteriaceae in ranges up to 107 cfu/mL. Carbapenemase producing Enterobacteriaceae and OXA 48-type CPE were present in ranges up to 105 cfu/mL. Out of 89 multiplied polymerase chain reaction (PCR) amplicons, only 36 were positive for different β-lactamase gene families, among those only three isolates were identified as multiresistant. The dominant ESBL family was CTXM in 19 different isolates. This was followed by 10 OXA-48 positive isolates and 10 VIM positive isolates. KPC or NDM carbapenemases were not identified with PCR screening of the isolates. Hospital wastewaters serve as a reservoir for nearly all clinically important antibiotic resistances. The importance of evaluating such potential environmental reservoirs is especially evident when outbreak cases could not be linked to an epidemiological source.</jats:p>

Efflux Pump-Driven Antibiotic and Biocide Cross-Resistance in Pseudomonas aeruginosa Isolated from Different Ecological Niches: A Case Study in the Development of Multidrug Resistance in Environmental Hotspots

“…It is also the first study of naturally developed cross-resistance that confirms findings previously only seen in laboratory-based studies. Our work also bestows credence to previous suggestions that healthcare-associated effluent could act as a hotspot for antimicrobial resistance development [39]. The reversal of resistance by the efflux pump inhibitor PAβN, direct measurement of efflux pump expression, and WGS confirmed mutational hyperexpression of the chromosomally encoded MexAB-OprM efflux pump as the main reason for the observed resistance and cross-resistance to antibiotics.…”

“…The highly adaptive and persistent nature of P. aeruginosa [ 6 ] coupled with the frequent use of biocides and antimicrobials in healthcare settings exert a further selective pressure on P. aeruginosa to acquire antimicrobial resistance. In particular, wastewater from healthcare sites has been defined as a “hot spot” for the acquisition of antimicrobial resistant determinants [ 39 ], as it serves as a reservoir for both antimicrobial residues and bacteria, presenting the perfect environment for the co-selection and development of antimicrobial resistance [ 19 , 24 , 40 , 41 ]. Although P. aeruginosa is known to be intrinsically resistant to biocides such as triclosan [ 42 ], epidemiologic cut-off values (ECOFF) for biocides are not currently available through the European Committee on Antimicrobial Susceptibility Testing (EUCAST) or Clinical and Laboratory Standards Institute (CLSI), making the determination of biocide resistance difficult.…”

Multidrug Resistant Klebsiella pneumoniae ST101 Clone Survival Chain From Inpatients to Hospital Effluent After Chlorine Treatment

“…Hospital wastewaters are highly complex effluents, carrying a wide range of micro- and macropollutants, including antibiotic compounds, metabolized drugs, disinfectants, patient excrements, and microorganisms. The presence of ARB as well as of antibiotic residues, which could inhibit the growth of susceptible bacteria, are thereby increasing the population of resistant bacteria in the receiving water ( Kaur et al, 2020 ; Rozman et al, 2020 ).…”

“…The dissemination of MDR K. pneumoniae strains from hospitals to the environment was previously demonstrated ( Mahon et al, 2017 ; Khan et al, 2018 ; Lepuschitz et al, 2019 ), highlighting the ability of these strains to survive and persists in environmental conditions. Despite this evidence, primary treatment of hospital wastewaters before their discharge in the urban sewage is not mandatory in many countries ( Hocquet et al, 2016 ; Rozman et al, 2020 ), these wastewaters ending up being treated in urban wastewater treatment plants. One of the primary treatments of hospital wastewaters used in Romania is represented by chlorine treatment, but the knowledge regarding the effects of chlorination on ARB is scarce.…”

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“…The dissemination of MDR K. pneumoniae strains from hospitals to the environment was previously demonstrated (Mahon et al, 2017;Khan et al, 2018;Lepuschitz et al, 2019), highlighting the ability of these strains to survive and persists in environmental conditions. Despite this evidence, primary treatment of hospital wastewaters before their discharge in the urban sewage is not mandatory in many countries (Hocquet et al, 2016;Rozman et al, 2020), these wastewaters ending up being treated in urban wastewater treatment plants. One of the primary treatments of hospital wastewaters used in Romania is represented by chlorine treatment, but the knowledge regarding the effects of chlorination on ARB is scarce.…”