sustainability Review Modern Analytical Techniques for Detection of Bacteria in Surface and Wastewaters Alexandra Canciu 1 , Mihaela Tertis 1 , Oana Hosu 1 , Andreea Cernat 1 , Cecilia Cristea 1, * and Florin Graur 2   Citation: Canciu, A.; Tertis, M.; Hosu, O.; Cernat, A.; Cristea, C.; Graur, F. Modern Analytical Techniques for Detection of Bacteria in Surface and Wastewaters. Sustainability 2021, 13, 7229. https:// doi.org/10.3390/su13137229 Academic Editors: Ilias Gialampoukidis, Ioannis Papoutsis, Demetrios Eliades and Stefanos Vrochidis Received: 23 May 2021 Accepted: 25 June 2021 Published: 28 June 2021 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). 1 Department of Analytical Chemistry, Iuliu Hat , ieganu University of Medicine and Pharmacy, 400000 Cluj-Napoca, Romania; alexandra.canciu@elearn.umfcluj.ro (A.C.); mihaela.tertis@umfcluj.ro (M.T.); hosu.oana@umfcluj.ro (O.H.); ilioaia.andreea@umfcluj.ro (A.C.) 2 Department of Surgery, Iuliu Hat , ieganu University of Medicine and Pharmacy, 400000 Cluj-Napoca, Romania; graurf@yahoo.com * Correspondence: ccristea@umfcluj.ro; Tel.: +40-0264-97256 Abstract: Contamination of surface waters with pathogens as well as all diseases associated with such events are a significant concern worldwide. In recent decades, there has been a growing interest in developing analytical methods with good performance for the detection of this category of contam- inants. The most important analytical methods applied for the determination of bacteria in waters are traditional ones (such as bacterial culturing methods, enzyme-linked immunoassay, polymerase chain reaction, and loop-mediated isothermal amplification) and advanced alternative methods (such as spectrometry, chromatography, capillary electrophoresis, surface-enhanced Raman scattering, and magnetic field-assisted and hyphenated techniques). In addition, optical and electrochemical sensors have gained much attention as essential alternatives for the conventional detection of bacteria. The large number of available methods have been materialized by many publications in this field aimed to ensure the control of water quality in water resources. This study represents a critical synthesis of the literature regarding the latest analytical methods covering comparative aspects of pathogen contamination of water resources. All these aspects are presented as representative examples, focus- ing on two important bacteria with essential implications on the health of the population, namely Pseudomonas aeruginosa and Escherichia coli. Keywords: bacteria detection; water analysis; analytical methods; water contamination 1. Introduction The safety of drinking water represents one of the major issues in today’s society. Water production and distribution need to meet some microbiological criteria to avoid becoming a serious health problem. The quality of water has been thoroughly monitored in the last decades because the presence of different pathogens or elements in water could seriously pose issues regarding human and environmental health. Water contamination could lead to serious environmental, health, and implicit economic problems that could continue over the decades, and the impact of contaminated water, whether contaminated directly or indirectly via alimentary products, can affect generations. An important issue at the international, national, regional, and local levels is access to safe drinking water, which is an issue of health and fundamental human rights. The importance of sanitation and access to drinking water could lead to economic benefits by reducing adverse effects and directly influencing overall healthcare costs [1]. “Water is essential to sustain life, and a satisfactory (adequate, safe, and accessible) supply must be available to all” [2]. The World Health Organization (WHO) International Standards were published between 1993 and 1997 after the Guidelines for Drinking-water Quality first and second editions (1983–1984). Sustainability 2021, 13, 7229. https://doi.org/10.3390/su13137229 https://www.mdpi.com/journal/sustainability