Proof of bacteria and the activity of chemical and natural antibiotics by headspace gas chromatography

Abstract

An efficient technique was developed to monitor the emission of hydrogen and carbon dioxide from bacteria cultures by headspace gas chromatography and to investigate the efficacy of chemical antibiotics and of natural compounds with antimicrobial properties. Facultative anaerobes emit hydrogen and carbon dioxide from cultures in the closed headspace vials and obligate anaerobes too, if the air above the cultures in the vials is replaced by nitrogen. Antibiotics added to the sample cultures are apparently effective if the emission of hydrogen and carbon dioxide is suppressed. If not, either they are ineffective or the related bacteria are even resistant. The headspace technique can detect bacterial contamination in various samples, and examples are presented for food purchased from supermarkets and for medical specimens, including recognition of antibiotic resistance. However, the described technique cannot identify the related bacteria at a species or genus level, but is well suited for example for screening the bulk of food in supermarkets for microbe contamination or for the search of natural antibiotics. The samples are incubated with the proper nutrient medium in closed septum vials which remain closed during the whole process. The personnel in the lab never come into contact with pathogens, and thus, safety regulations are warranted. The described technique can be carried out with all commercially available gas chromatographs, even including simple low-cost instruments, equipped with a standard packed column and a thermal conductivity detector, up to expensive and fully automated instruments, such as used for forensic blood alcohol analysis.

Monitoring of Hydrogen Emission from Bacteria in Food, Animals and in the Blood of Humans Suffering from Lyme Disease by A Specific Hydrogen Sensor

“…The charged vials were then cultured at 35 °C but the necessary time depends on the reproduction rate of the relevant bacteria. In general, after 12 h a measurable H 2 peak can be obtained [ 6 ]. Some bacteria, e.g., spirochetes, were cultured for three days due to their slow reproduction rate.…”

“…We have investigated a limited number of natural antibiotics, such as seed of cress, teasel, propolis, tree resin and also some essential oils, but with varying and not unambiguous success, depending on the sample type, the relevant bacteria and some other parameters. From these compounds, only garlic ( Allium sativum ) and oil of cloves ( Eugenia caryophyllus ) have emerged as universally applicable natural antibiotics [ 6 , 7 ] and two such examples are presented here. The addition of the oil of cloves to the contaminated meat of cockerel ( Figure 3 a) in the cultured samples eliminated the bacterial contamination contrary to penicillin.…”

“…The other antibiotic favorite was garlic, administered as capsules for this study, which are more convenient and above all less unpleasant than rough garlic [ 6 ]. Garlic was applied against Borrelia + in infected ticks and in the blood of patients suffering from tick-borne Lyme disease.…”

“…The proof of emitted H 2 , therefore, was taken in this work to recognize bacterial contamination in food and medical specimens and can be applied particularly to screening applications without the ambition to identify the relevant bacteria which may then be performed subsequently with proven methods. Such an application by HS-GC for proving bacterial contamination in vegetables, animal food and medical specimens has been described [ 6 ]. In addition, the contamination of ticks by Borrelia and their transfer to humans causing Lyme disease [ 7 ] has been investigated.…”

Non-destructive Electromagnetic Wave Sensor for Hazardous Biological Materials

“…However, the existing technologies mostly are analytical instruments which require highly skilled and trained workers and are costly to manufacture and maintain in a laboratory [1]. Examples include fluorescence spectroscopy [2], mass spectrometry [3] , gas chromatography and matrix-assisted laser desorption ionization (MALDI) [4]. A number of investigators have described biosensors capable of analysis of [5,6].…”