Electronic measurement of bacterial growth

Richards, Jim; Jason, A C; Hobbs, Graham; Gibson, D. M.; Christie, R H

doi:10.1088/0022-3735/11/6/017

Cited by 113 publications

(60 citation statements)

References 8 publications

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“…The viable counts were always lower than the bioluminescence counts. The difference in counts determined for the unexposed controls, however, was generally within the accepted 0.5-log1o error inherent with viable counting (16). The discrepancy, however, varies with the bacterial strain and is most likely to be due to the difference in the fragilities between the resultant aberrant morphologies.…”

Section: Resultsmentioning

confidence: 53%

“…The third and fourth PAE values were computed from the impedance data. Calculation of PAE values by using the Malthus microbial growth analyzer relies on the numbers of bacterial cells at time zero after antibiotic elimination, and these numbers have previously been determined by performing viable counts (3,4 [2] where t(107)e is the time taken for the antibiotic-exposed culture to reach 107 organisms per ml, t(107)" is the time taken for the unexposed control to reach 107 organisms per ml, tg' is a function of the generation time (16), noe is the number of bacteria present in the test culture after antibiotic exposure and subsequent elimination, and n0c is the number of bacteria similarly present in the control culture (14).…”

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confidence: 99%

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Postantibiotic effect of meropenem on members of the family Enterobacteriaceae determined by five methods

Mackenzie

Gould

Chapman

et al. 1994

Antimicrob Agents Chemother

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The postantibiotic effect (PAE) of meropenem was determined for 11 strains, both clinical isolates and reference strains of members of the family Enterobacteriaceae. The study compares PAE results obtained by five methods used to monitor bacterial regrowth, including viable counting, alone and in combination with impedance; bioluminescence, alone and in combination with impedance; and a morphological technique. After exposure of the test organisms to meropenem (0.1 x to 100 x MIC) for 2 h, concentration-dependent differences in counts by bioluminescence and viable counts were observed, the latter always being lower. The differences varied with the test organism. For example, after exposure ofProvidentia stuartii NCTC 10318 to 0.1 x MIC, the counts were 5.5 x 105 and 2.0 x l05 whereas after exposure of Citrobacter freundii MR76 to 0.1x MIC of meropenem the counts were 2.3 x 106 and 6.8 x 103 by bioluminescence and viable counting, respectively. The discrepancies were probably due to the relative inability of the viable counting procedure to detect fragile aberrant morphologies and resulted in differences in the calculated PAE values. With methods which do not detect fragile morphologies, the PAE may be underestimated. A general trend was observed for the order of magnitude of the PAEs by the following methods (in order of decreasing magnitude of PAE): (i) morphological technique, (ii) bioluminescence technique alone, (iii) bioluminescence in combination with impedance, (iv) viable counting in combination with impedance, and (v) viable counting alone. It is our opinion that of the methods examined in this study, bioluminescence in combination with impedance best reflects the true values for PAEs, and these results were examined more closely.Postantibiotic effect (PAE), the delayed regrowth of bacteria after antibiotic exposure, is now a well-established phenomenon that was first described almost 50 years ago (1). The effect appears to be a feature of virtually all antimicrobial agents and has been observed for a wide variety of bacteria and yeasts. It is, however, the specific antimicrobial agent-organism combination which determines the presence and duration of the PAE. Investigators using both old and new ,-lactams have consistently observed a PAE with gram-positive cocci (2). In contrast, after exposure of gram-negative bacilli to ,-lactams, PAEs, if any, are of short duration or have a negative value. PAE values obtained are, however, very dependent on the methods used to quantify the effect (8, 12). Bearing in mind that gram-negative bacilli generally form fragile spheroplasts when exposed to meropenem, the suitability of performing viable counts on these cell forms has been questioned, and it was found that an underestimation of the number of cells by viable counting led to an underestimation of the PAE (9,13,15). This study extends these observations of some members of the family Enterobacteriaceae by using an impedance technique (3) in conjunction with a bioluminescence assay of bacterial ATP (6) and compa...

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Section: Resultsmentioning

confidence: 53%

mentioning

confidence: 99%

Postantibiotic effect of meropenem on members of the family Enterobacteriaceae determined by five methods

Mackenzie

Gould

Chapman

et al. 1994

Antimicrob Agents Chemother

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show abstract

“…Today most bacteria counts are still determined by standard plate count (SPC) or psychrotrophic bacteria count (PBC) [2], which are labor and time intensive. Microbiological impedance devices [3][4][5][6][7][8] provide a less labor intensive way to estimate bacteria count in a biological medium. Microbiological impedance devices measure the permittivity and/or impedance spectra of the biological medium by immersing two or three electrodes into the medium and measuring the voltage at a constant current.…”

Section: Introductionmentioning

confidence: 99%

Remote Query Resonant-Circuit Sensors for Monitoring of Bacteria Growth: Application to Food Quality Control

Ong

Bitler

Grimes

et al. 2002

Sensors

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This paper presents a technique for in-situ remote query monitoring of bacteria growth utilizing a printed thin or thick-film sensor comprised of an inductor-capacitor (LC) resonant circuit. The sensor, which is placed within the biological medium of interest and remotely detected using a loop antenna, measures the complex permittivity of the medium. Since bacteria growth increases the complex permittivity of a biological medium the LC sensor can be used to determine bacteria concentration. This paper presents results on monitoring of three different bacteria strains, Bacillus subtilis, Escherichia coli JM109, and Pseudomonas putida, demonstrating application of the sensor for monitoring bacteria growth in milk, meat, and beer. Due to its low unit cost and remote query detection, the sensor is potentially useful for commercial scale monitoring of food quality.

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“…These metabolites are responsible for the decrease in the impedance of the medium [2,[12][13][14]. After the important work of Torry Research Station [15] in 1978 and Eden and Eden [16] in 1984, and Owens et al [17] in 1989 reporting the principle of indirect impedance, several efforts have been made on the detection of Salmonella by impedance-based technology in food samples [9,12,13,[18][19][20][21][22][23].…”

Section: Implications Of Electrical Impedance-based Microbiological Tmentioning

confidence: 99%

Implications of Electrical Impedance-Based Microbiological Technology in Pork Meat Processing Industry for the Rapid Detection and Quantification of Salmonella Spp.

Pablos¹,

Marugán²,

Cristóbal³

et al. 2017

JFSE

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Abstract:The absence of efficient tools for preventing bacterial contamination in the meat processing industry as well as for detecting Salmonella positive samples in real time is a matter of concern. Impedance technology has proved its effectiveness as a bacterial quantification tool for research purposes instead of laborious standard plate count, and as a detection tool to substitute tedious current horizontal method ISO 6579:2002. Calibration curves were carried out for S. enteritidis and S. typhimurium in raw pork matrix (R 2 > 0.90). Calibrations of mixtures of both strains at different ratio were prepared, showing a high efficiency to differentiate bacterial metabolism. Impediometry was also validated against standard plate count in raw pork samples treated by UV-C illumination to inactivate Salmonella. Even, damaged but still viable bacteria were recorded. Detection of Salmonella by impediometry led to a decrease in false positives, obtaining results within 30 h compared to 72 h in case of conventional method.

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Electronic measurement of bacterial growth

Cited by 113 publications

References 8 publications

Postantibiotic effect of meropenem on members of the family Enterobacteriaceae determined by five methods

Postantibiotic effect of meropenem on members of the family Enterobacteriaceae determined by five methods

Remote Query Resonant-Circuit Sensors for Monitoring of Bacteria Growth: Application to Food Quality Control

Implications of Electrical Impedance-Based Microbiological Technology in Pork Meat Processing Industry for the Rapid Detection and Quantification of Salmonella Spp.

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