Bacterial dynamics in drinking water distribution systems and flow cytometry monitoring scheme optimization

2021 ◽  
Vol 286 ◽  
pp. 112151
Author(s):  
Marco Gabrielli ◽  
Andrea Turolla ◽  
Manuela Antonelli
2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
G. Liu ◽  
E. J. Van der Mark ◽  
J. Q. J. C. Verberk ◽  
J. C. Van Dijk

The objective of this study was to evaluate the application of flow cytometry total cell counts (TCCs) as a parameter to assess microbial growth in drinking water distribution systems and to determine the relationships between different parameters describing the biostability of treated water. A one-year sampling program was carried out in two distribution systems in The Netherlands. Results demonstrated that, in both systems, the biomass differences measured by ATP were not significant. TCC differences were also not significant in treatment plant 1, but decreased slightly in treatment plant 2. TCC values were found to be higher at temperatures above 15°C than at temperatures below 15°C. The correlation study of parameters describing biostability found no relationship among TCC, heterotrophic plate counts, and Aeromonas. Also no relationship was found between TCC and ATP. Some correlation was found between the subgroup of high nucleic acid content bacteria and ATP (R2=0.63). Overall, the results demonstrated that TCC is a valuable parameter to assess the drinking water biological quality and regrowth; it can directly and sensitively quantify biomass, detect small changes, and can be used to determine the subgroup of active HNA bacteria that are related to ATP.


2020 ◽  
Vol 41 (S1) ◽  
pp. s255-s255
Author(s):  
Ayodele T. Adesoji ◽  
Adeniyi A. Ogunjobi

Background: Multidrug-resistant bacteria can lead to treatment failure, resulting in infectious diseases being transferred through nonpotable water. Aminoglycosides are an important class of antibiotics that are abused in Nigeria. Few studies have investigated aminoglycoside-modifying genes (AMGs) that are likely responsible for resistance in Nigeria bacteria isolates. Therefore, we aimed to characterize AMGs from isolates in drinking water distribution systems (DWDS) in southwestern Nigeria. Methods: Multidrug-resistant bacteria (n = 181) that had been previously characterized by 16S rDNA sequencing and that were positive for resistance to at least 1 aminoglycoside antibiotic were selected from 6 treated and untreated water distribution systems. Strains were PCR genotyped for 3 AMGs: aph(3)c, ant(3)b and aph(6)-1dd. Results: Of 181 MDR bacteria tested, 69 (38.12%) were positive for at least 1 of the AMGs. The most common was ant(3)c (27.6%), followed by aph(3")c (18.23%). Both aph(3)c and ant(3")b were found in 7.73% of tested isolates, ant(3)b was most commonly found in Alcaligenes spp (50%). Furthermore, aph(3")c was most commonly detected in Proteus spp (50%). Other genera positive for AMGs included Acinetobacter, Aeromonas, Bordetella, Brevundimonas, Chromobacterium, Klebsiella, Leucobacter, Morganella, Pantoae, Proteus, Providencia, Psychrobacter, and Serratia. Conclusions: High occurrence of ant(3)c and aph(3)c among these bacteria call for urgent attention among public health workers because these genes can be easily disseminated to consumers if present on mobile genetic elements like plasmids, integrons, and transposons.Funding: NoneDisclosures: None


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