Abundance and antibiotic resistance of non-O1 Vibrio cholerae strains in domestic wastewater before and after treatment in stabilization ponds in an arid region (Marrakesh, Morocco)

Biological HRPs in wastewater

Biological high-risk pollutants (HRPs) have become a serious threat to human health worldwide, and wastewater is one of the major sources of them in a natural environment. Despite the long history of wastewater research, comprehensive understanding of the role and behavior of HRPs during wastewater treatment is still limited owing to the complexity of the community. In recent decades, the rapid development of molecular tools, especially the wide application of next generation sequencing technologies, helps to unravel the community composition, structure, and dynamic variation in wastewater. Overall, this chapter mainly focuses on biological HRPs, including bacteria, viruses, protozoa, helminth, biotoxins, antibiotic resistance genes and antibiotic resistant bacteria in wastewater. The characteristics, classification, fates, functions, and health implications of these HRPs are introduced in detail. Moreover, the biogeography of HRPs is a research hotspot in recent years, and available information is also summarized in this chapter. Finally, we also propose the future research needs of HRPs in wastewater after the comprehensive summary of the existing research reports. This chapter is wished to be helpful for beginners to quickly understand the biological HRPs in wastewater.

Vibrio Species in Wastewater Final Effluents and Receiving Watershed in South Africa: Implications for Public Health

Wastewater treatment facilities in South Africa are obliged to make provision for wastewater effluent quality management, with the aim of securing the integrity of the surrounding watersheds and environments. The Department of Water Affairs has documented regulatory parameters that have, over the years, served as a guideline for quality monitoring/management purposes. However, these guidelines have not been regularly updated and this may have contributed to some of the water quality anomalies. Studies have shown that promoting the monitoring of the current routinely monitored parameters (both microbial and physicochemical) may not be sufficient. Organisms causing illnesses or even outbreaks, such as Vibrio pathogens with their characteristic environmental resilience, are not included in the guidelines. In South Africa, studies that have been conducted on the occurrence of Vibrio pathogens in domestic and wastewater effluent have made it apparent that these pathogens should also be monitored. The importance of effective wastewater management as one of the key aspects towards protecting surrounding environments and receiving watersheds, as well as protecting public health, is highlighted in this review. Emphasis on the significance of the Vibrio pathogen in wastewater is a particular focus.

Antimicrobial Susceptibility among Urban Wastewater and Wild Shellfish Isolates of Non-O1/Non-O139 Vibrio cholerae from La Rance Estuary (Brittany, France)

The early 2000s marked the end of the Golden age of the antibiotics and the beginning of the awareness on the potential threat to human health due to the dissemination of antimicrobial resistance. As a base-line study, we investigated the antimicrobial susceptibility of 99 strains of non-O1/non-O139 Vibrio cholerae isolated from wastewater and shellfish in 2000/2001 within La Rance estuary (Brittany, France). All isolates were susceptible to amoxicillin-clavulanic acid, cefotaxime, imipenem, chloramphenicol, nalidixic acid, ciprofloxacin, norfloxacin, amikacin, gentamicin, tetracycline, doxycycline, trimethoprim-sulfamethoxazole, and erythromycin. The only resistances were to streptomycin, sulfonamides and ampicillin: 54.6% of the isolates had acquired resistance to at least one antimicrobial agent among them and only six isolates from cockles were multidrug resistant. On the basis of the distribution of a limited selection of resistance associated genes, our study shows that V. cholerae can constitute an environmental reservoir for these genes. However, none of our isolates harbored integron. This result casts doubt on the capacity of non-O1/non-O139 V. cholerae to acquire resistance-associated genes in such context, and on its potential role of indicator of the dissemination of antimicrobial resistance in the aquatic environment.

Occurrence of Vibrio pathotypes in the final effluents of five wastewater treatment plants in Amathole and Chris Hani District Municipalities in South Africa

We assessed the occurrence of Vibrio pathogens in the final effluents of five wastewater treatment plants (WWTPs) located in Amathole and Chris Hani District Municipalities in South Africa over a 12 months period between September 2012 and August 2013 using standard membrane filtration technique followed by cultivation on thiosulphate citrate-bile salts-sucrose (TCBS) agar. The identities of the presumptive Vibrio isolates were confirmed using polymerase chain reaction (PCR) including delineation into V. parahaemolyticus, V. vulnificus and V. fluvialis pathotypes. The counts of Vibrio spp. varied with months in all the study sites and ranged in the order of 10¹ and 10⁴ CFU/100mL. Vibrio distribution also showed seasonality with high counts being obtained in autumn and spring (p < 0.05). Prevalence of Vibrio spp. among the five WWTPs also differed significantly (p < 0.05). Of the 300 isolates that were confirmed as belonging to the Vibrio genus, 29% (86) were V. fluvialis, 28% (84) were V. vulnificus and 12% (35) were V. parahaemolyticus. The isolation of Vibrio pathogens from the final effluent suggests that this pathogen is in circulation in some pockets of the population and that the WWTPs under study do not efficiently remove bacterial pathogens from the wastewater and consequently are threats to public health.

Rapid discrimination of environmental Vibrio by matrix-assisted laser desorption ionization time-of-flight mass spectrometry

The aim of this study was to discriminate 30 Vibrio strains isolated from two wastewater treatment plants from Agadir, Morocco by two molecular typing methods, pulsed-field gel electrophoresis (PFGE) and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS). Out of the 30 strains of Vibrio examined in this study, 5 isolates could not be typed by PFGE and consistently appeared as a smear on the gel. In general, high genetic biodiversity among the Vibrio strains was found regardless to the isolation source. The results of MALDI TOF analysis show a high congruence of strain grouping demonstrating the accuracy and reliability of MALDI-TOF MS.

Environmental pollutions impacts on the bacteriological and physicochemical quality of suburban and rural groundwater supplies in Marrakesh area (Morocco)

This study scrutinized bacteriological and chemical quality of groundwater supplies of Marrakesh (Morocco) within a year. It assessed the influence of some chemical factors on fecal and opportunistic pathogenic bacterial communities. The annual average densities of fecal coliforms, fecal streptococci and Pseudomonas aeruginosa were respectively: 1891 colony forming units (CFU)/100 mL, 1246 CFU/100 mL and 206 CFU/100 mL. The total occurrence of these bacteria during the period of study was 94%. Detectable non-O1 Vibrio cholerae was present in 81% of samples and the mean abundances ranged from 0 to 11100 MPN/100 mL. Significant correlations between fecal coliforms and streptococci and between fecal coliforms and non-O1 V. cholerae (p < 0.01) were found. Fecal coliforms can be used to detect the presence of non-O1 V. cholerae in this groundwater. These well waters were greatly mineralized, hard, salt with high concentrations of nitrogenous ions and major elements (Ca(2+), Na(+), Cl(-), SO(2-)(4) and K(+)). Most of chemical parameters were relatively steady with time except for calcium, ammonium, nitrites and organic matter which were seasonally influenced. The degree of correlation between chemical parameters and the abundances of isolated bacteria is heterogeneous. The concentrations of calcium and nitrites favored (p < 0.01) the abundance of fecal coliforms and streptococci, but reduced P. aeruginosa abundances. Calcium, salinity, chlorides, nitrites and nitrates tests can be used for screening in situ when the laboratory facilities are limited. This work is expected to assist local authorities in developing plans and actions to reduce the pollution to acceptable levels.