Lactose Broth for Isolating Bacterium Coli From Water

Wagner, E.; Monfort, W. F.

doi:10.2105/ajph.11.3.203

Cited by 11 publications

(4 citation statements)

References 15 publications

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“…coli in some of the tests also. Our conclusions were confirmed by Wagner and Monfort (20), Stearn (21) and Hinman (22). The use of gentian violet in the lactose broth presumptive test greatly increased its practical value by eliminating nearly all of the positive tests due to Gram-positive organisms.…”

Section: The Presumptive Testsupporting

confidence: 88%

The Practical Utility of Bacteriologic Control of Water Supplies

Hall¹

1928

Journal AWWA

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The sole significance of bacteria in water supplies relates to the transmission of the water borne diseases,-typhoid fever, the paratyphoids (alpha and beta), the dysenteries (protozoan and bacterial), and cholera. The specific causes of all of these diseases were discovered since 1880 and the accumulating epidemiological evidence that they were frequently transmitted by drinking water led immediately to the hope that their detection in water might serve as a criterion of its potability.But this hope was soon frustrated, for the occasions upon which these organisms have been isolated directly from naturally polluted water supplies are few indeed. There are three principal reasons why the intestinal pathogens can only rarely be recovered from water supplies, (1), the relatively small number of organisms present in proportion to non-pathogenic forms, (2), their transitory persistence in water, (3), their uniform lack of distinguishing characteristics among many harmless species naturally present.For these reasons the water sanitarian has been mainly interested in discovering criteria of pollution rather than the detection and recognition of specific causative agents of disease in water. The useful criteria are both chemical and bacteriological.Chemical tests of water polluted with sewage show abnormal quantities of chlorides, derived from kitchen wastes, urine and feces, and a high organic content as indicated by nitrogenous compounds and a large oxygen demand. The form in which nitrogen is present is quite important; ammonia indicates recent pollution, while nitrites and nitrates indicate more remote pollution owing to partial or complete oxidation.But the more direct criteria of fecal pollution are bacterial. This 1 Presented before the Rocky Mountain Section meeting,

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Section: The Presumptive Testsupporting

confidence: 88%

The Practical Utility of Bacteriologic Control of Water Supplies

Hall¹

1928

Journal AWWA

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“…PbEc colonization levels in mice that did not receive antibiotic treatment, as determined by enumeration of cultured PbEc from feces and qPCR, were consistent throughout the experiment (∼10 9 -10 10 CFU/gram feces, ∼10 5 copies/µl) ( Figure 2B, Figure S6 ). PbEc colonization levels, however, rapidly decreased and were no longer detectable in cefepime treated mice by day 6 ( Figure 2B ), even after using E. coli growth enrichment techniques 47 . After 7 days of cefepime administration, mice were euthanized, and intestinal tissues were harvested.…”

Section: Resultsmentioning

confidence: 99%

Susceptible bacteria survive antibiotic treatment in the mammalian gastrointestinal tract without evolving resistance

Rodrigues

Sabaeifard

Yildiz

et al. 2023

Preprint

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In vitro systems have provided great insight into the mechanisms of antibiotic resistance. Yet, in vitro approaches cannot reflect the full complexity of what transpires within a host. As the mammalian gut is host to trillions of resident bacteria and thus a potential breeding ground for antibiotic resistance, we sought to better understand how gut bacteria respond to antibiotic treatment in vivo. Here, we colonized germ–free mice with a genetically barcoded antibiotic pan–susceptible Escherichia coli clinical isolate and then administered the antibiotic cefepime via programmable subcutaneous pumps which allowed for closer emulation of human parenteral antibiotic pharmacokinetics/dynamics. After seven days of antibiotics, we were unable to culture E. coli from feces. We were, however, able to recover barcoded E. coli from harvested gastrointestinal (GI) tissue, despite high GI tract and plasma cefepime concentrations. Strikingly, these E. coli isolates were not resistant to cefepime but had acquired mutations — most notably in the wbaP gene, which encodes an enzyme required for the initiation of the synthesis of the polysaccharide capsule and lipopolysaccharide O antigen - that increased their ability to invade and survive within intestinal cells, including cultured human colonocytes. Further, these E. coli mutants exhibited a persister phenotype when exposed to cefepime, allowing for greater survival to pulses of cefepime treatment when compared to the wildtype strain. Our findings highlight a mechanism by which bacteria in the gastrointestinal tract can adapt to antibiotic treatment by increasing their ability to persist during antibiotic treatment and invade intestinal epithelial cells where antibiotic concentrations are substantially reduced.

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“…We have found that the final H-ion concentrations of several tubes of lactose broth filled from the same batch always agree very closely. Wagner and Monfort (1921) in their discussion on lactose broth raise the following point:…”

Section: Statementioning

confidence: 99%