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PubMed2000

Novel online infusate-assisted dialysis system performs microbiologically safely.

Administration of adequate amounts of commercial infusion fluids renders modern convective dialysis modalities, such as hemodiafiltration, labor-intensive and costly. Preparation of infusate by cold sterilization of dialysis fluid, which is abundantly available, and its immediate (online) use, in contrast, enables a large volume fluid exchange in a cost-effective manner. Recent developments aimed at more hygienic and user-friendly online systems with increased operational flexibility. As a result the novel ONLINEplus system does not only provide online prepared infusate for convective dialysis therapy, but also for priming and rinsing of the extracorporeal blood circuit, for intradialytic bolus administration, and for re-infusion of patients' blood as well. Production of infusate from potentially impure dialysis fluid containing endotoxins and other pyrogens raises severe concerns of affecting the patients' well-being. To assess its safety, the online system was challenged with microbially contaminated dialysis fluid. Despite high levels of microbial counts (7.5 x 104 +/- 105 CFU/ml), endotoxin concentration (14.1 +/- 7.7 IU/ml and 9.265 +/- 3.000 IU/ml, as measured turbidimetrically and chromogenically, respectively) and cytokine-inducing activity (20,827 +/- 3,082 pg IL-1Ra/Mio WBC), we failed to detect contaminants in the final infusate during a 5 week laboratory testing period. In addition, infusate samples complied consistently with the European Pharmacopeia test for sterility. The present online system is comprehensive, operates user-friendly, and provides microbiologically safe infusate in large quantities. In this way, both patients and dialysis staff will benefit from improved dialysis therapy and reduced treatment-related labor burden, respectively. Moreover, convective dialysis modalities will become less expensive.

Analysis of Variance↗
PubMed2003

Distribution of selected bacterial species on intraoral surfaces.

BACKGROUND/AIM: To examine the proportions of 40 bacterial species in samples from 8 oral soft tissue surfaces and saliva in systemically healthy adult subjects and to compare these microbiotas with those of supra- and subgingival plaque. METHODS: Microbial samples were taken from 8 oral soft tissue surfaces of 225 systemically healthy subjects using a "buccal brush". Saliva was taken by expectoration. Forty-four of these subjects provided additional supra- and subgingival plaque samples. Samples were individually evaluated for their content of 40 bacterial species using checkerboard DNA-DNA hybridization. The percentage of total DNA probe count was determined for each species, at each sample location and averaged across subjects. The significance of differences among the proportions of the 40 test species at different sample locations was sought in the 225 and 44 subjects separately using the Quade test and adjusted for multiple comparisons. Cluster analysis was performed using the proportions of the 40 species at the different sample locations using the minimum similarity coefficient and an average unweighted linkage sort. The proportions of each species were averaged across subjects in the resulting cluster groups and the significance of differences was tested using the t-test and ANOVA. RESULTS: Microbial profiles differed markedly among sample locations in the 225 subjects, with 34 of 40 species differing significantly. Proportions of Veillonella parvula and Prevotella melaninogenica were higher in saliva and on the lateral and dorsal surfaces of the tongue, while Streptococcus mitis and S. oralis were in significantly lower proportions in saliva and on the tongue dorsum. Cluster analysis resulted in the formation of 2 clusters with >85% similarity. Cluster 1 comprised saliva, lateral and dorsal tongue surfaces, while Cluster 2 comprised the remaining soft tissue locations. V. parvula, P. melaninogenica, Eikenella corrodens, Neisseria mucosa, Actinomyces odontolyticus, Fusobacterium periodonticum, F. nucleatum ss vincentii and Porphyromonas gingivalis were in significantly higher proportions in Cluster 1 and S. mitis, S. oralis and S. noxia were significantly higher in Cluster 2. These findings were confirmed using data from the 44 subjects providing plaque samples. The microbial profiles of supra- and subgingival plaque differed from the other sample locations, particularly in the increased proportions of the Actinomyces species. Species of different genera exhibited different proportions on the various intraoral surfaces, but even within the genus Streptococcus, there were differences in colonization patterns. S. oralis, S. mitis and S. constellatus colonized the soft tissues and saliva in higher proportions than the samples from the teeth, while the other 4 streptococcal species examined colonized the dental surfaces in proportions comparable to the soft tissue locations and saliva. CONCLUSIONS: Proportions of bacterial species differed markedly on different intraoral surfaces. The microbiota of saliva was most similar to that of the dorsal and lateral surfaces of the tongue. The microbiotas of the soft tissues resembled each other more than the microbiotas that colonized the teeth both above and below the gingival margin.

Adult↗
PubMed1992

Influence of pefloxacin on microbial colonization resistance in healthy volunteers.

The influence of pefloxacin, 400 mg twice daily for ten days, on microbial colonization resistance was investigated in six healthy volunteers. In three volunteers impairment of colonization resistance was indicated by a significant increase in the faecal concentration of yeasts. In two of them, impairment of colonization resistance was confirmed by facilitation of colonization by a challenge strain of Klebsiella pneumoniae in the early post-treatment period. It is concluded that pefloxacin impairs colonization resistance in some volunteers. However, during pefloxacin therapy, overgrowth by aerobic bacteria is prevented by the very high antimicrobial concentration in faeces, and after therapy it is prevented by rapid restoration of colonization resistance.

Colony Count, Microbial↗
PubMed2005

Dynamics of indigenous yeast populations during spontaneous fermentation of wines from Mendoza, Argentina.

Fermentation of wine is a complex microbial reaction, which involves the sequential development of various species of yeasts and lactic acid bacteria. Of these, yeasts are the main group responsible for alcoholic fermentation. The aim of this work was to study, under industrial conditions, the evolution of yeast populations and to describe the individual evolution of the most important yeasts during three spontaneous fermentations of Malbec musts from Argentina. This work shows the significant participation of non-Saccharomyces yeasts during spontaneous fermentation of musts, with the ubiquitous presence of three main species: Kloeckera apiculata, Candida stellata and Metschnikowia pulcherrima.

Colony Count, Microbial↗
PubMed2002

Street foods in Accra, Ghana: how safe are they?

OBJECTIVE: To investigate the microbial quality of foods sold on streets of Accra and factors predisposing to their contamination. METHODS: Structured questionnaires were used to collect data from 117 street vendors on their vital statistics, personal hygiene, food hygiene and knowledge of foodborne illness. Standard methods were used for the enumeration, isolation, and identification of bacteria. FINDINGS: Most vendors were educated and exhibited good hygiene behaviour. Diarrhoea was defined as the passage of > or =3 stools per day) by 110 vendors (94.0%), but none associated diarrhoea with bloody stools; only 21 (17.9%) associated diarrhoea with germs. The surroundings of the vending sites were clean, but four sites (3.4%) were classified as very dirty. The cooking of food well in advance of consumption, exposure of food to flies, and working with food at ground level and by hand were likely risk factors for contamination. Examinations were made of 511 menu items, classified as breakfast/snack foods, main dishes, soups and sauces, and cold dishes. Mesophilic bacteria were detected in 356 foods (69.7%): 28 contained Bacillus cereus (5.5%), 163 contained Staphylococcus aureus (31.9%) and 172 contained Enterobacteriaceae (33.7%). The microbial quality of most of the foods was within the acceptable limits but samples of salads, macaroni, fufu, omo tuo and red pepper had unacceptable levels of contamination. Shigella sonnei and enteroaggregative Escherichia coli were isolated from macaroni, rice, and tomato stew, and Salmonella arizonae from light soup. CONCLUSION: Street foods can be sources of enteropathogens. Vendors should therefore receive education in food hygiene. Special attention should be given to the causes of diarrhoea, the transmission of diarrhoeal pathogens, the handling of equipment and cooked food, hand-washing practices and environmental hygiene.

Adult↗
PubMed2004

PCR method based on the ogdH gene for the detection of Salmonella spp. from chicken meat samples.

In a previous paper, the ogdH gene that encodes 2-oxoglutarate dehydrogenase was isolated from Salmonella typhimurium. The catalytic N-terminal region in the enzyme was found to be very specific for the Salmonella species. Therefore, the aim of the present study was to detect S. typhimurium in food sources using primers designed for OGDH-1 and OGDH-2 which were based on the salmonella-specific region of the ogdH gene. A simple polymerase chain reaction (PCR) detection method was developed to detect low numbers of S. typhimurium in a chicken meat microbial consortium. Using the ogdH-specific primers under stringent amplification conditions and for gene probe analysis, fewer than 100 colony-forming units (CFUs) were detectable when pure cultures were employed. When the PCR assay was run on S. typhimurium-contaminated meat contents, only the positive meat samples containing as few as 200 CFUs reacted to the assay. The method employed for sample processing is simple and it was determined to provide a sensitive means of detecting trace amounts of S. typhimurium-specific sequences in the presence of mixed meat microbial populations. When compared with six representative intestinal gram-negative bacterial strains in foods, including Vibrio parahaemolyticus, V. vulnificus, Enterobacter cloacae, E. coli O157:H7, Pseudomonas aeruginosa, and Proteus sp., S. typhimurium had a unique and distinct PCR product (796 bp). In conclusion, the two OGDH primers were found to be rapid and sensitive detectors of Salmonella spp for the PCR method.

Animals↗
PubMed1988

Bacterial colonization of the tracheobronchial tree.

Bacterial colonization of the tracheobronchial tree is a significant problem in hospitalized and chronically ill individuals. Colonization occurs because of both microbial and host factors, with the foremost mechanism being adherence of pathogenic gram-negative bacteria to mucosal epithelial cells. In the pathogenesis of nosocomial pneumonia, colonization appears to be an essential first step. In the diagnostic approach to hospital-acquired pneumonia, a distinction must be made between colonization and true lower respiratory tract infection. Future approaches to the major problem of colonization with gram-negative bacteria will require a better understanding of pathogenesis and employ strategies that not only focus upon limiting the bacterial pathogens but also attempt to improve upon pulmonary defense mechanisms.

Bronchopneumonia↗
PubMed2005

Effect of gamma irradiation on the microbiological quality of minimally processed vegetables.

The initial microflora of minimally processed celery and cabbage packaged under a modified atmosphere was determined. The samples came from the same producer and were sold in a supermarket chain of Santiago, Chile. Although neither E. coli nor Salmonella spp. were detected, initial total plate and Enterobacteriaceae counts were high (= 10(5) cfu/g), not meeting in most cases the specifications of the Chilean legislation. The D10 value for two strains of E. coli (ATCC 8739 and a wild type) inoculated as indicator microorganisms was determined. After irradiating with 5 D10 doses (1kGy), the variation of the microbial population and sensory quality during a 7 days storage period at 5 degrees C was studied. In irradiated celery, a reduction of 4.7 and 3.8 logs for total plate and Enterobacteriaceae counts respectively was observed. There was a decrease of 3.8 and 3.6 logs in cabbage for total plate and Enterobacteriaceae counts respectively. In both irradiated and non-irradiated vegetables, neither E. coli nor Salmonella spp. were detected. An increase of 1.6 - 1.7 logs in both microbiological parameters in non-irradiated samples was observed during storage. In irradiated products, only celery showed an increase of 1.2 log in total plate count. Both Enterobacteriaceae count in the two vegetables and Total plate count in cabbage presented essentially no variation in time. No significant differences (p = 0.05) were detected in sensory total quality between the control and the irradiated vegetable and between days of storage.

Apium↗
PubMed1992

Effect of an experimental antiplaque preparation on salivary microbial counts in military academy cadets refraining from mechanical cleaning of the teeth.

Dental emergencies in the army are mostly due to infections of the teeth, caused by dental plaque micro-organisms. Because practicing normal oral hygiene is restricted during terrain maneuvers, for example, we developed a new antiseptic tablet preparation which can be used to make an antiplaque solution or even chewed and thus mixed with saliva to rinse the mouth. The preparation contains chlorhexidine, fluoride, and xylitol (XYLIHEX) and can be added to the soldier's kit. The efficiency of the preparation on selected oral micro-organisms was tested against mouthwash solutions containing plain chlorhexidine (CHX) and sodium fluoride (F) in 45 military cadets who volunteered to participate in this double-blind cross-over study. The results showed a significant decrease in salivary mutants streptococci after rinsing periods with XYLIHEX and CHX when compared with F (p less than 0.001). Lactobacilli and yeast counts were not affected. The new preparation appeared promising as a new means for improving soldiers' oral hygiene.

Adult↗
PubMed2005

Correlation between faecal microbial community structure and cholesterol-to-coprostanol conversion in the human gut.

Intensity of the cholesterol-to-coprostanol conversion in the intestine, as assessed by the coprostanol-to-cholesterol ratio in faeces, was found highly variable among 15 human volunteers, ranging from absent to almost complete cholesterol conversion. The number of coprostanoligenic bacteria in the same faecal samples, as estimated by the most probable number method, was found to be less than 10(6) cellsg-1 of fresh stools in the low-to-inefficient converters and at least 10(8) cellsg-1 of fresh stools in the highest converters, indicating that the population level of cultivable faecal coprostanoligenic bacteria correlated with the intensity of cholesterol-to-coprostanol conversion in the human gut. Microbial communities of the samples were profiled by temporal temperature gradient gel electrophoresis (TTGE) of bacterial 16S rRNA gene amplicons. Dendrogram analysis of the TTGE profiles using the Pearson product moment correlation coefficient and a unweighted pair group method with arithmetic averages (UPGMA) algorithm clearly separated banding patterns from low-to-inefficient and high converters in two different clusters suggesting a relationship between TTGE profiles and coprostanoligenic activity. Principal components analysis further demonstrated that a large subset of bands rather than some individual bands contributed to this clustering.

Adult↗
PubMed2006

Biological implications from an autonomous version of Baranyi and Roberts growth model.

An autonomous version of Baranyi and Roberts model (Int. J. Food Microbiology, 23, 1994, pp. 277-294) is developed and analyzed to reveal some subtle points, which are difficult to observe accurately from its equivalent non-autonomous form. In particular we are able to provide a meaningful interpretation to the "physiological state of the cells at inoculation", a parameter introduced by Baranyi and Roberts [Baranyi, J., Roberts, T. A., 1994. A dynamic approach to predicting bacterial growth in food. International Journal of Food Microbiology 23, 277-294] that has a profound impact on microbial growth but is not a direct measurable quantity. In addition, the analysis shows that the transient growth depends on the initial cell concentration and the initial growth rate, but is independent of "the history of the cells" and depends only indirectly (via the initial growth rate) on the previous (pre-inoculation) environment. The stationary solution is independent of the initial conditions. A new, more natural, and biologically meaningful formulation of LAG duration is being suggested in terms of initial conditions being in the neighborhood of one of the unstable stationary points revealed by this autonomous version of the model.

Bacteria↗
PubMed1992

DNA probe and enzyme analysis in periodontal diagnostics.

Recent research in periodontology has indicated that a finite number of bacterial species are associated with periodontal disease. This has generated the hypothesis that periodontal disease is essentially an infection due to one or more of the putative periodontopathogens; i.e., the specific plaque hypothesis (SPH). This microbial specificity paradigm has already changed the way researchers and some clinicians view periodontal disease. The clinician must heed several cautions signs, however, if he is to use the SPH to provide treatment options that could enhance the delivery of care. There are several diagnostic technologies that can be used to detect and semi-quantitate those bacterial species that have been identified as periodontopathogens. This paper discusses diagnostic tests based upon the detection in plaque of DNA segments or enzyme activity(ies) that are unique for one or more of the suspected periodontopathogens.

Aggregatibacter actinomycetemcomitans↗
PubMed2004

Microbiological evaluation of commercial probiotic products available in Italy.

Scientific evidence of the prevention and therapy of some intestinal diseases is accumulating in regard to probiotic products. However, sufficient information on the use of probiotics in specific therapies is not yet available and, above all, there is no clear legislation about these products in Europe. In this study, we evaluated five different probiotic products commercially available in Italy for their qualitative and quantitative microbial content after about 12 and 22 months of storage. We also evaluated the stability of lactobacilli to 0.3% bile salts and to pH of 3.58 and 7.98. There were discrepancies between the declared content and our results found after storage for 4 of the tested products. Bile salts and basic pH did not affect the growth of the lactobacilli tested, while for 2 tested products 6 hours at acid pH produced a complete inhibition of bacterial growth. Our results suggest the need for clear legislation and adequate control of the manufacturing of probiotic products.

Colony Count, Microbial↗
PubMed1999

Combined use of acetic acid treatment and modified atmosphere packaging for extending the shelf-life of chilled chicken breast portions.

Samples of chicken breasts with skin were treated with a 1% acetic acid solution or untreated and packaged in a 70% CO2/30% N2 modified atmosphere. Two different types of films were studied to establish their usefulness within the above pre-determined conditions. After 3, 7, 14 and 21 d of storage at 4 degrees C, the samples were evaluated for spoilage microbial growth, odour and slime, as well as the gas composition in the headspace volume in the package. As a result of this, it was found that both films were adequate for using them as barriers. Samples treated with the acetic acid solution smelt slightly acidic and pleasant, while the untreated ones had 'off' odours at the end of the storage periods. However, all samples showed acceptable overall aspect by that time. Acetic acid treatment produced decreases in counts in all genera studied. Results of this study indicate that using modified atmosphere packaging (MAP) on chicken breasts previously decontaminated with acetic acid is a worthwhile technology to extend samples shelf-life.

Acetic Acid↗
PubMed2003

Lethal photosensitization in microbiological treatment of ligature-induced peri-implantitis: a preliminary study in dogs.

This pilot study evaluated, by culture testing, the effectiveness of lethal photosensitization for the microbiological treatment of peri-implantitis in dogs. Experimental peri-implantitis was induced by ligature placement for 2 months. Following ligature removal, plaque control was instituted by scrubbing with 0.12% chlorhexidine daily for 12 months. Subsequently, mucoperiosteal flaps were elevated for scaling the implant surface. Microbial samples were obtained with paper points before and after treatment of implant surfaces by means of 100 microg/ml toluidine blue O (TBO,) and were exposed, for 80 s, to light with a wavelength of 685 nm from a 50 mW GaAlAs diode laser. The mean initial and final bacterial counts were 7.22 +/- 0.20 and 6.84 +/- 0.44 CFU/ml, respectively for TVC (P < 0.0001); 6.19 +/- 0.45 and 3.14 +/- 3.29 CFU/ml for P. intermedia/nigrescens (P = 0.001); 5.98 +/- 0.38 and 1.69 +/- 2.90 CFU/ml for Fusobacterium spp. (P = 0.001); and 6.07 +/- 0.22 to 1.69 +/- 2.94 CFU/ml for beta-hemolytic Streptococcus (P = 0.0039). It may be concluded that lethal photosensitization resulted in a reduction of the bacterial count. Complete elimination of bacteria was achieved in some samples.

Animals↗
PubMed1993

The effect of tetronasin and monensin on fermentation, microbial numbers and the development of ionophore-resistant bacteria in the rumen.

The Gram-negative rumen bacteria Fibrobacter succinogenes S85, Prevotella ruminicola M384 and Veillonella parvula L59 were grown in media containing successively increasing concentrations of the ionophores, monensin and tetronasin. All three species became more resistant to the ionophore with which they were grown. Increased resistance to one ionophore caused increased resistance to the other, and cross-resistance to another ionophore--lasalocid--and an antibiotic--avoparcin. Recovery of tetronasin-resistant bacteria from the rumen of monensin-fed sheep increased and vice versa, indicating that similar cross-resistance occurred in vivo.

Animals↗
PubMed2005

Series quartz crystal sensor for remote bacteria population monitoring in raw milk via the Internet.

A remote monitoring system based on a piezoelectric quartz crystal (SPQC) sensor was developed for the determination of the bacteria population in raw milk. The system employs the Windows XP server operating system, and its programs for data acquisition, display and transmission were developed using the LabVIEW 7.1 programming language. The circuit design consists of a circuit with a piezoelectric quartz crystal (SPQC) and a pair of electrodes. This system can provide dynamic data monitoring on a web-page via the Internet. Immersion of the electrodes in a cell culture with bacteria inoculums resulted in a change of frequency caused by the impedance change due to microbial metabolism and the adherence of bacteria on the surface of the electrodes. The calibration curve of detection times against density of bacteria showed a linear correlation coefficient (R(2) = 0.9165) over the range of 70-10(6) CFU ml(-1). The sensor could acquire sufficient data rapidly (within 4 h) and thus enabled real-time monitoring of bacteria growth via the Internet. This system has potential application in the detection of bacteria concentration of milk at dairy farms.

Animals↗
PubMed2005

Investigation for possible source(s) of contamination of ready-to-eat meat products with Listeria spp. and other pathogens in a meat processing plant in Trinidad.

In 2003, there was a recall of three processed (chicken franks, spice ham and turkey ham ready-to-eat (RTE) meat products by a large processing plant in Trinidad as a result of contamination by Listeria monocytogenes. The study was conducted to investigate the possible source(s) of Listeria contamination of recalled RTE meat products and to determine the prevalence of Listeria spp., Salmonella spp., Escherichia coli and Campylobacter spp. in the products and air within the plant. Raw and processed meat products, as well as food contact surfaces were also tested for Salmonella spp., Listeria spp. and Campylobacter spp. initially after thorough clean-up and close-down of the plant. Faecal and effluent samples from the piggery, in close proximity to the plant, were tested for the presence of Salmonella spp., Listeria spp. and Campylobacter spp. Air samples and food contact surfaces were negative for the tested organisms. Ten (58.8%) of the 17 effluent samples and 4 (11.8%) of the 34 faecal samples were positive for Campylobacter coli. Of the 11 raw meat products tested, 10 (90.9%) were positive for E. coli and Listeria spp. either singly or in combination. Of the 32 processed RTE products tested, 11 (34.4%) were positive for E. coli, Salmonella spp., Listeria spp. and Campylobacter spp. in combination or singly. Eleven (61.1%) of 18 processed products contained unacceptable levels of aerobic bacteria using international standards. Four months later, following the implementation of recommended cleaning, sanitizing and hygienic practices at the plant, pre- and post-processed products were sampled and Listeria spp. were identified in 4 (80.0%) of the 5 raw products and in 1 of the 5 (20.0%) finished products. Two (40.0%) of the finished products contained unacceptable microbial levels. It was concluded that the close proximity of the piggery to the processing plant was not the probable source of Listeria contamination of the recalled meat products. The data suggested that improved sanitary practices on food contact surfaces and during handling of products, reduced the risk of Listeria spp. and other pathogens studied. The problem at the plant can therefore, be inferred to be due to lapses in good sanitary practices, inadequate heat treatments or the presence of pathogens particularly Listeria in biofilms on different surfaces continuously or occasionally contaminating finished products.

Air Microbiology↗