Comparison of the Most Probable Numbers of Escherichia coli and Enterococci in River Waters

Litsky, Warren; Mallmann, W. L.; Fifield, Charles W.

doi:10.2105/ajph.45.8.1049

Cited by 54 publications

(13 citation statements)

References 8 publications

(2 reference statements)

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“…Biological removal factors include antibiosis, predation by nematodes, protozoa and zooplankton, attack by lytic bacteria and viruses and natural die-off. [9] Also, the ratio between FC and FS is used to distinguish between human and nonhuman coliform contamination. [6] Measurement of human pathogenic organisms in untreated and treated wastewater is expensive and technically challenging.…”

Section: Introductionmentioning

confidence: 99%

Removal of Enteric Bacteria in Constructed Treatment Wetlands with Emergent Macrophytes: A Review

Vymazal¹

2005

Journal of Environmental Science and Health, Part A

131

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Domestic and municipal sewage contains various pathogenic or potentially pathogenic microorganisms which, depending on species concentration, pose a potential risk to human health and whose presence must therefore be reduced in the course of wastewater treatment. The removal of microbiological pollution is seldom a primary target for constructed treatment wetlands (CWs). However, wetlands are known to act as excellent biofilters through a complex of physical, chemical and biological factors which all participate in the reduction of the number of bacteria. Measurement of human pathogenic organisms in untreated and treated wastewater is expensive and technically challenging. Consequently, environmental engineers have sought indicator organisms that are (1) easy to monitor and (2) correlate with population of pathogenic organisms. The most frequently used indicators are total coliforms, fecal coliforms, fecal streptococci and Escherichia coli. The literature survey of 60 constructed wetlands with emergent vegetation around the world revealed that removal of total and fecal coliforms in constructed wetlands with emergent macrophytes is high, usually 95 to > 99% while removal of fecal streptococci is lower, usually 80-95%. Because bacterial removal efficiency is a function of inflow bacteria number, the high removal effects are achieved for untreated or mechanically pretreated wastewater. Therefore, the outflow numbers of bacteria are more important. For TC and FC the outflow concentrations are usually in the range of 10(2) to 10(5) CFU/ 100 ml while for FS the range is between 10(2) and 10(4) CFU/ 100 ml. Results from operating systems suggest that enteric microbe removal efficiency in CWs with emergent macrophytes is primarily influenced by hydraulic loading rate (HLR) and the resultant hydraulic residence time (HRT) and the presence of vegetation. Removal of enteric bacteria follows approximately a first-order relationship.

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Section: Introductionmentioning

confidence: 99%

Removal of Enteric Bacteria in Constructed Treatment Wetlands with Emergent Macrophytes: A Review

Vymazal¹

2005

Journal of Environmental Science and Health, Part A

131

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“…Enterococci (Ent) in raw source waters were enumerated in modified Rothe medium (Buttiaux 1958) by the MPN technique by inoculating three series of five tubes 10, 1 and 0.1 ml). Confirmation of positive enrichment cultures was carried out in Litsky medium (Litsky et al 1955) at 37°C. In the case of chlorine-treated waters, membrane filtration followed by culture on Slanetz medium incubated at 37°C for 48 h was used; confirmation of positive enrichment cultures was performed according to AFNOR (Anon.…”

Section: Methodsmentioning

confidence: 99%

Assessment of the marker value of various components of the coli‐aerogenes group of Enterobacteriaceae and of a selection of Enterococcus spp. for the official monitoring of drinking water supplies

Charriere

Mossel²,

Beaudeau

et al. 1994

Journal of Applied Bacteriology

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The traditional indicators Escherichia coli (in practice currently, though ecologically inaccurately, represented by 'thermotolerant coliforms' at 44 degrees C) and Enterococcus spp. proved to be suitable for the diagnosis of heavy and frequent faecal pollution observed in potentially dangerous waters, especially those originating from karstic aquifers. On the other hand, natural and treated waters, slightly and inconsistently contaminated, occasionally showed a variable Gram-negative flora, difficult to classify by routine tests. In that case, complete identification of isolates may be necessary to ensure a valid decision on the potability of the supply. At any rate some of the Enterobacteriaceae contained in the 'faecal coliform' group and many other 'coliforms', distinct from E. coli, lack sanitary significance although their presence at certain levels may indicate inadequate disinfection, hiatuses in the integrity of the distribution system or both.

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“…Nelle acque luride, i coliformi e gli enterococchi classici sono presenti in numero elevato, ma i coliformi sono stati trovati in concentrazione circa 13 volte maggiore rispetto a quella degli enterococchi 50 . Leininger e McCleskey 48 hanno osservato che gli enterococchi non si moltiplicano in acqua, come fanno talvolta i coliformi.…”

Section: Distribuzioneunclassified

Indicatori di qualità microbiologica e di sicurezza degli alimenti

2009

Food

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Alcuni microrganismi possono essere impiegati come indicatori della qualità microbiologica degli alimenti, in relazione sia alla durata dei prodotti, sia all'assenza di agenti patogeni. In generale, gli indicatori sono utilizzati soprattutto per valutare la sicurezza e l'igiene degli alimenti e saranno trattati in tale contesto in gran parte del capitolo. È possibile, tuttavia, utilizzare anche indicatori di qualità e alcuni aspetti generali di tale impiego saranno delineati nel prossimo paragrafo. Alcuni indicatori di qualità di prodottoGli indicatori della qualità microbiologica o della shelf life di un prodotto sono microrganismi e/o loro metaboliti, la cui presenza in determinati alimenti, a definite concentrazioni, può essere impiegata per valutare la qualità o, meglio, per predire la shelf life del prodotto. Per essere utilizzati a tale scopo, i microrganismi indicatori devono soddisfare i seguenti criteri. Capitolo 20 Indicatori di qualità microbiologica e di sicurezza degli alimenti 511 J.M. Jay et al., Microbiologia degli alimenti © Springer-Verlag Italia 2009 Microbiologia degli alimenti 512 Tabella 20.

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Comparison of the Most Probable Numbers of Escherichia coli and Enterococci in River Waters

Cited by 54 publications

References 8 publications

Removal of Enteric Bacteria in Constructed Treatment Wetlands with Emergent Macrophytes: A Review

Removal of Enteric Bacteria in Constructed Treatment Wetlands with Emergent Macrophytes: A Review

Assessment of the marker value of various components of the coli‐aerogenes group of Enterobacteriaceae and of a selection of Enterococcus spp. for the official monitoring of drinking water supplies

Indicatori di qualità microbiologica e di sicurezza degli alimenti

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