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PubMed2005

Fungal infections of fresh-cut fruit can be detected by the gas chromatography-mass spectrometric identification of microbial volatile organic compounds.

There is a large and rapidly growing market for fresh-cut fruit. Microbial volatile organic compounds indicate the presence of fungal or bacterial contamination in fruit. In order to determine whether microbial volatile organic compounds can be used to detect contamination before fruit becomes unmarketable, pieces of cantaloupe, apple, pineapple, and orange were inoculated with a variety of fungal species, incubated at 25 degrees C, then sealed in glass vials. The volatiles were extracted by headspace solid-phase microextraction and analyzed by gas chromatography-mass spectrometry. Forty-five compounds were identified that might serve as unique identifiers of fungal contamination. Fungal contamination can be detected as early as 24 h after inoculation.

Consumer Product Safety↗

PubMed2007

Detection of in situ derivatized peptides in microbial biofilms by laser desorption 7.87 eV postionizaton mass spectrometry.

A novel analytical method based on laser desorption postionization mass spectrometry (LDPI-MS) was developed to investigate the competence and sporulation factor-a pentapeptide of amino acid sequence ERGMT-within intact Bacillus subtilis biofilms. Derivatization of the neat ERGMT peptide with quinoline- and anthracene-based tags was separately used to lower the peptide ionization potential and permit direct ionization by 7.87-eV vacuum ultraviolet radiation. The techniques of mass shifting and selective ionization of the derivatized peptide were combined here to permit detection of ERGMT peptide within intact biofilms by LDPI-MS, without any prior extraction or chromatographic separation. Finally, imaging MS specific to the derivatized peptide was demonstrated on an intact biofilm using LDPI-MS. The presence of ERGMT in the biofilms was verified by bulk extraction/LC-MS. However, MALDI imaging MS analyses were unable to detect ERGMT within intact biofilms.

Amino Acid Sequence↗

PubMed1989

Application of non-radioactive BACTEC system to sterility testing and hygiene.

The applicability of the non-radioactive BACTEC NR 660 system for the detection of low viable counts of aerobic and anaerobic bacteria (including non-fermenters and aerobic spore-forming bacteria) and fungi was investigated. The BACTEC system together with the usual BACTEC NR 6A and NR 7A media was able to detect most of the organisms without supplementation of the media; for growth of lactobacilli and other acidophilic organisms, sterile orange juice was used as a supplement. Microbial growth was detected from pure cultures and also from artificially contaminated beverages and ointment bases. Detection times varied according to the types of metabolism of the respective strains and their initial viable counts, but usually they were detected after 20 to 42 h of incubation. The BACTEC NR 660 system seems to be applicable not only for blood cultures in medical microbiology but also in pharmaceutical and food industry.

Bacteria↗

PubMed2003

Metabolism of dietary procyanidins in rats.

Procyanidins are major dietary polyphenols made of elementary flavan-3-ol (epi)catechin units. They have antioxidant properties and may contribute to health benefits in humans, but little is known about their metabolic fate. We compared here the metabolism of procyanidin dimer B3, trimer C2, and polymer isolated from willow tree catkins to that of catechin monomer in rats. These compounds were administered in the rat diet (0.1%, w/w) for 5 d and their metabolites estimated in 24 h urine. In rats fed procyanidins, neither parent compound nor catechin derivatives could be detected in contrast to animals fed catechin monomer, which excreted large amounts of catechin and its 3'-O-methylated form (25.7 +/- 0.6%). On the other hand, 16 metabolites of microbial origin were detected and identified as phenylvaleric, phenylpropionic, phenylacetic, and benzoic acid derivatives. Their total yields significantly decreased from the catechin monomer (10.6 +/- 1.1%) to the procyanidin dimer (6.5 +/- 0.2%), trimer (0.7 +/- 0.1%), and polymer (0.5 +/- 0.1%). Therefore, the degree of procyanidin polymerization has a major impact on their fate in the body characterized by a poor absorption through the gut barrier and a limited metabolism by the intestinal microflora as compared to catechin. This will have to be considered to explain the health effects of procyanidins. The contribution of their microbial metabolites should also be further investigated.

Animals↗

PubMed1994

Haemolytic anaemia in association with Escherichia coli O157 infection in two sisters.

Two sisters, 2 and 5 years of age, suffered from acute haemolytic anaemia occurring after gastroenteritis with Escherichia coli O157. One patient developed clinical signs of severe and acute intravascular haemolysis and sepsis. She received transfusion and antibiotic therapy. The second patient presented with mild to moderate haemolytic symptoms only. None of them developed renal impairment. In serum of both children, elevated titres of short-lived agglutinins were demonstrated in the indirect haemagglutination assay consisting of sheep erythrocytes coated with lipopolysaccharide from E. coli O157. By immunoblot analysis IgM antibodies against the O157 lipopolysaccharide were demonstrated in the acute phase sera but not in follow up sera taken 2 months after disease. On erythrocyte membranes, adsorption of microbial antigens was detected by use of a pool-immunoglobulin fluorescence test. The immunological status of both patients was normal. Complete recovery from haemolytic disease was observed without further therapy. Microbial antigens attached to the cell surface were assumed to be the pathophysiological cause of E. coli O157 associated haemolytic anaemia in two siblings.

Acute-Phase Reaction↗

PubMed2003

Use of a similarity index based on microbial fatty acid (MFA) analysis to monitor biological wastewater treatment systems.

Estimating the stability of microbial community structures may be useful in advanced biological wastewater treatment system design and operation. In this research, a monitoring method using fatty acid profiles was evaluated for detecting changes in microbial community structures. For the evaluation, the operating parameters such as pH, organic loading, and chlorine addition were varied in two identical laboratory scale conventional activated sludge systems. A similarity index based on microbial fatty acid analysis was used to express the stability of microbial community structures in the systems. Experiments using a model microbial community showed that microbial compositions changed daily even under constant operating conditions and that the rate of change increased under dynamic operating conditions. Substrate changes brought about a relatively large change in a microbial community structure, eventually resulting in a very different microbial community. After only 7 days following a substrate change in a lab-scale bioreactor, the biomass exhibited only 45% similarity to the original structure. The analysis of microbial fatty acids conveys additional information, in that it could be used for the calculation of biomass concentrations in a wastewater treatment system if microbial fatty acid analyses are executed on a routine basis as a monitoring tool for biological wastewater treatment systems. The total fatty acid concentrations were about 0.61% of the biomass concentration as mixed liquor volatile suspended solid concentrations in this research.

Bacteria↗

PubMed1993

Detection of Legionella pneumophila in biofilms containing a complex microbial consortium by gas chromatography-mass spectrometry analysis of genus-specific hydroxy fatty acids.

A gas chromatographic-mass spectrometric method was used to detect Legionella pneumophila in biofilms in potable water containing a complex microbial consortium. The unique 3-hydroxy and 2,3-dihydroxy fatty acids of the L. pneumophila lipopolysaccharides (LPS) were detected in both the planktonic phase of the continuous culture model and in the biofilms forming on both copper and polyethylene substrata. The technique confirmed that lower numbers of Legionella colonised and grew on copper in comparison to polyethylene and offers promise for routine detection of Legionella in biofilms in the environment.

Fatty Acids↗

PubMed1990

Role of bacterial debris in inflammatory diseases of the joint and eye.

Several distinct rheumatic conditions (including Lyme arthritis, Reiter's syndrome and rheumatic fever) as well as certain forms of the blinding disease, uveitis, may share a common etiology. In each instance specific bacterial pathogens may infect a distant site, which on interaction with the immune system, leads to a sterile inflammation in the joint or eye. These "reactive" conditions may result, in some cases, from prior localization of non-viable bacterial remnants (including the cell wall or peptidoglycan) or alternatively "dormant" fastidious bacteria in the affected joint or eye where they act as persisting antigens. Classical culture techniques, would not detect the presence of these putative microbial antigens. Alternative approaches for detection of ubiquitous components of bacteria in the host (using appropriate chemical, molecular and immunological techniques) are discussed.

Acetylmuramyl-Alanyl-Isoglutamine↗

PubMed2000

[Thermal trauma in a combination with respiratory tract burn].

The detection rate of microbial contamination of burn wounds after flame burn was studied in dynamics to 3 weeks in 56 patients forming 2 similar groups: basic--with thermo-inhalation lesions (TIL) and control--without TIL. General area of skin burns in all the patients was less than 50% of the body surface, on average it was 40%, the area of deep burns was 23%. Cytological and bacteriologic methods were used for study microphlora in the sputum and in bronchoalveolar lavage. There were 186 cases of wound microbial contamination (gram-negative microorganisms--64.4% cases, gram-positive--34%, pathogenic fungi--1.6%). In 80% cases the microphlora of the wounds was polymicrobial, in 47% cases the microphlora were detected on the second week. Microphlora was detected 2 times more often in the basic group than in the control, corresponded to skin burn area; the greatest exceeding of critical level of wound contamination was revealed on the first 2 weeks. In TIL besides wound contamination, polymicrobial microphlora revealed in tracheobronchial tree, presented on the first 2 weeks with association of gram-positive and gram-negative microorganisms, combining on week 3 with fungal phlora. Early leukocytosis, not reducing during first 3 weeks of the study, due to intoxication by burn products, occurred in TIL. Early lymphopenia in TIL was the sign of resistant immunodeficiency.

Adolescent↗

PubMed2006

Direct molecular approach to monitoring bacterial colonization on vacuum-packaged beef.

Denaturing gradient gel electrophoresis allowed us to monitor total bacterial communities and to establish a pattern of succession between species in vacuum-packaged beef stored at 2 and 8 degrees C for 9 weeks and 14 days. Species-specific PCR was used to confirm the presence of Lactobacillus sakei and Lactobacillus curvatus. Multiplex PCRs using 16S rRNA-specific primers allowed differentiation between Leuconostoc species. These methods provided the desired information about microbial diversity by detecting the main microorganisms capable of colonizing this ecological niche.

Animals↗

PubMed1995

Controlled evaluation of BacT/alert standard anaerobic and FAN anaerobic blood culture bottles for the detection of bacteremia and fungemia.

FAN medium was formulated to improve microbial recovery, particularly for fastidious microorganisms and for microorganisms causing sepsis in patients receiving antimicrobial therapy. In a controlled clinical evaluation performed at four university-affiliated hospitals, FAN anaerobic bottles were compared with standard anaerobic bottles for yield, speed of detection of microbial growth, and detection of septic episodes. A total of 10,431 blood culture sets were received; both anaerobic bottles of 7,694 blood culture sets were adequately filled with blood. Altogether, 925 isolates were recovered: 557 that were the cause of sepsis, 99 that were indeterminate as the cause of sepsis, and 269 contaminants. More Staphylococcus aureus (P < 0.001), coagulase-negative staphylococci (P < 0.001), Escherichia coli (P < 0.02), and all microorganisms combined (P < 0.005) were recovered from FAN bottles; more nonfermentative gram-negative bacilli (P < 0.05), Torulopsis glabrata (P < 0.001), and other yeasts (P < 0.01) were recovered from standard bottles. Growth of S. aureus (P < 0.001), coagulase-negative staphylococci (P < 0.001), Enterococcus faecalis (P < 0.025), streptococci other than Streptococcus pneumoniae (P < 0.01), and all microorganisms combined (P < 0.001) was detected earlier in standard bottles; growth of more isolates of E. coli (P < 0.05) and anaerobic bacteria (P < 0.01) was detected earlier in FAN bottles. The mean times to detection were 14.2 and 16.1 h for standard and FAN bottles, respectively. More septic episodes caused by S. aureus (P < 0.001), coagulase-negative staphylococci (P < 0.005), members of the family Enterobacteriaceae (P < 0.02), and all microorganisms combined (P < 0.02) were detected in FAN bottles; more septic episodes caused by nonfermentative gram-negative bacilli (P < 0.025) and yeasts (P < 0.005) were detected in standard bottles. In summary, more isolates (except for strict aerobes) were recovered from FAN bottles than from standard anaerobic bottles. Similarly, significant more septic episodes (except for those caused by strict aerobes) were detected with FAN bottles than with standard anaerobic bottles. With the exception of E. coli and anaerobic bacteria, growth of more isolates was detected earlier in standard anaerobic bottles.

Aerobiosis↗

PubMed1991

Soil and groundwater transport of microorganisms.

Releases of GEMs into the environment are expected to increase in the next few years, with the most dramatic increases resulting from the application of pest-control agents in agriculture and forestry. Of major significance in assessing the environmental risk impact of GEMs is an understanding of their survival and transport in soil and subsurface environments. While information on the transport and survival of microorganisms through soil is available, it is neither abundant nor extensive in terms of microbial types tested or soils examined. Though the transport of microorganisms from an application site depends primarily upon passive mechanisms, broad generalizations pertaining to the transportability of a specific microorganism within a particular soil environment may not be possible. Indeed, to extrapolate from information about one microbe to another, or from one geographical location to another, may not be appropriate. What is clear, however, is that the broader the data base, the more powerful the argument for making reasoned judgement, and consequently the more satisfactory the results of the predictive process. Several inherent difficulties exist in studying the transport behavior of GEMs in soil and subsurface environments. Detection of low microbial numbers or of stressed microbial populations is exceedingly difficult with traditional technology. In an effort to improve detection sensitivity, many improved methods of monitoring GEMs in the soil and subsurface are currently under development (Chaudhry et al. 1989). Beyond the difficulties of making accurate measurements of microorganisms to determine their spatial and temporal situation in the soil and subsurface environment, lies the need to ascertain the dynamic relationships between indigenous populations of microorganisms and how they may interact with a released GEM. Also, research strategies have not adequately addressed methods to predict the potential interactions between GEMs and natural microorganisms. These issues must be addressed if environmental risk assessment is to be valuable. There is clearly a need for focused research on the survival and transport of GEMs in these environments.

Bacteria↗

PubMedDate not supplied

[Effect of various methods of immobilization on stability of a microbial biosensor based on Pseudomonas rathonis T during detection of surfactants].

The operating and storage stability of a receptor element of an amperometric biosensor based on the Pseudomonas rathonis strain T capable of degrading surfactants was tested. Microbial cells were immobilized by incorporation in gels (agar, agarose, and calcium-alginate), polyvinyl alcohol membrane, adhesion to the chromatographic paper GF/A, or by the cross-linking induced by glutaric aldehyde. Incorporation of microbial cells in agar gel provides the long-standing conservation of their activity and viability during measurements of high concentrations of surfactants and allows the receptory element of the biosensor to be rapidly recovered after the measurements.

Biosensing Techniques↗

PubMed1981

Immunodiagnosis of invasive pulmonary aspergillosis in rabbits. Fungal antigen detected by radioimmunoassay in bronchoalveolar lavage fluid.

To improve antemortem diagnosis of invasive pulmonary aspergillosis, we used a radioimmunoassay to detect an Aspergillus fumigatus antigen in bronchoalveolar lavage fluid (BALF) and evaluated this technique in a model of disseminated aspergillosis. Antigen was detected in 91% of BALF samples obtained from 11 rabbits with major pulmonary aspergillosis. In an additional 10 rabbits with only minor pulmonary involvement, antigen was detected in 40% of concentrated lavage samples. In contrast, antigenlike activity was found in only 1 of 17 BALF samples from control animals with systemic candidiasis, in none of 9 control animals with staphylococcal pneumonia and in none of 10 normal control animals. Although antigen was present in the serum of 76% of animals infected with Aspergillus, 27% of those with major pulmonary involvement had antigen detected in BALF alone. We found that an extracellular microbial antigen can be detected in BALF and that this technique in the disseminated aspergillosis model is both sensitive and specific for invasive pulmonary disease.

Animals↗

PubMed1995

A comparison of the microbial flora in carious dentine of clinically detectable and undetectable occlusal lesions.

It is not known whether the aetiology of occlusal hidden caries lesions (HCL) is identical to that of small visible lesions (SVL). Previous studies of the microflora of HCL suggest that relatively few species can be isolated. The aim of the present study was to compare the bacterial composition of dentine from 10 HCL and 17 SVL in a population of children aged 8-18 years. The following bacteria were identified: Actinomyces spp., mutans streptococci, Streptococcus sanguis, Streptococcus oralis, Streptococcus gordonii. Streptococcus mitis, and Lactobacillus spp. Streptococcus mutans was found more often in the HCL group (p = 0.03), while Streptococcus sobrinus was found more often in the SVL group (p = 0.05). However, proportions of both species were lower in the SVL group as compared with the HCL group (S. mutans p = 0.07; S. sobrinus p = 0.03). Lactobacilli and Actinomyces spp. were found at similar levels in both groups. A more diverse range of streptococcal species and Veillonella was found in the SVL group (p = 0.001). These results show a less complex microflora in HCL as compared with SVL, indicating that the aetiology of hidden caries might be different from that of open caries.

Actinomyces↗

PubMed2001

Sampling and detection of Legionella pneumophila aerosols generated from an industrial cooling tower.

Cooling tower water has frequently been cited as a source of infection in outbreaks of Legionnaires' disease. However, there have been few reports on the presence of legionellae in aerosols from cooling towers. This paper describes our use of an impinger or a six-stage microbial impactor for detecting legionellae in air around a cooling tower contaminated with L. pneumophila (1.2+/-0.3x10(5) CFU/100 ml). Phosphate-buffered saline, Page's saline, 2% yeast extract solution and buffered yeast extract (BYE) broth were tested to evaluate their collection efficiency. These solutions were compared in laboratory experiments using an aerosol of L. pneumophila serogroup (SG) 1. Because BYE broth was the most efficient and storable collecting fluid among them, it was used for outdoor air sampling. In the outdoor air sampling, aerosolized L. pneumophila SG 6 was detected in the air around the cooling tower by the impinger (0.09 CFU/l. air). No legionellae were detected by the impactor with Legionella-selective agar plates (WYOalpha) because the plates were overgrown with fungi. Repetitive element PCR (rep-PCR) and arbitrarily primed PCR (AP-PCR) were employed to assess the epidemiological relationship among Legionella isolates from the air sample and the cooling tower water samples. L. pneumophila SG 6 isolated from the aerosols produced rep-PCR and AP-PCR fingerprints identical to those of L. pneumophila SG 6 strains from the cooling tower water, suggesting that the bacterium was aerosolized from the cooling tower.

Aerosols↗

PubMed2006

Molecular microbial diversity of a soil sample and detection of ammonia oxidizers from Cape Evans, Mcmurdo Dry Valley, Antarctica.

The aim of our study was to estimate the uncultured eubacterial diversity of a soil sample collected below a dead seal, Cape Evans, McMurdo, Antarctica by an SSU rDNA gene library approach. Our study by sequencing of clones from SSU rDNA gene library approach revealed high diversity in the soil sample from Antarctica. More than 50% of clones showed homology to Cytophaga-Flavobacterium-Bacteroides group; sequences also belonged to alpha, beta, gamma proteobacteria, Thermus-Deinococcus and high GC gram-positive group; Phylogenetic analysis of the SSU rDNA clones showed the presence of species belonging to Cytophaga spp., Vitellibacter vladivostokensis, Aequorivita lipolytica, Aequorivita crocea, Flavobacterium spp., Flexibacter sp., Subsaxibacter broadyi, Bacteroidetes, Roseobacter sp., Sphingomonas baekryungensis, Nitrosospira sp., Nitrosomonas cryotolerans, Psychrobacter spp., Chromohalobacter sp., Psychrobacter okhotskensis, Psychrobacter fozii, Psychrobacter urativorans, Rubrobacter radiotolerans, Marinobacter sp., Rubrobacteridae, Desulfotomaculum aeronauticum and Deinococcus sp. The presence of ammonia oxidizing bacteria in Antarctica soil was confirmed by the presence of the amoA gene. Phylogenetic analysis revealed grouping of clones with their respective groups.

Ammonia↗

PubMed2000

Will genome detection replace serology in blood screening for microbial agents?

The residual risk of transfusion-transmitted viral infection in developed countries is considered minimal or negligible. However, zero risk remains a strong political objective. Genomic screening for HCV, HIV and HBV represents a major advance, eliminating infectious blood donations collected during the pre-seroconversion window period, rare cases of immunosilent infections and, possibly, a large spectrum of viral variants. In Western countries, HCV RNA genomic screening started on pools of 16-400 plasma samples from individual donations. Pooling may produce false-positive and false-negative results. Individual donation testing is more suitable to blood screening but requires multiplexing, automation, and affordable cost. Because donations from individuals who are HBV DNA-negative/serologically positive, or those apparently recovered from HCV infection, may remain infectious, it is unlikely that HBsAg, anti-HCV, and anti-HIV will be discontinued when genomic screening is extended to all three viruses. HIV-1 p24 antigen may prove redundant with HIV RNA screening. Anti-HTLV-I and HTLV-II will remain more effective than genomic testing.

Antibodies, Viral↗