Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Colony Count, Microbial”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,135 records · Page 63Linked to original sources
PubMed2005

Microbiologic determinants of exacerbation in chronic obstructive pulmonary disease.

BACKGROUND: The culture of bronchial secretions from the lower airway has been reported to be positive for potentially pathogenic microorganisms (PPMs) in patients with stable chronic obstructive pulmonary disease (COPD), but the determinants and effects of this bacterial load in the airway are not established. METHODS: To determine the bronchial microbial pattern in COPD and its relationship with exacerbation, we pooled analysis of crude data from studies that used protected specimen brush sampling, with age, sex, smoking, lung function, and microbiologic features of the lower airway as independent variables and exacerbation as the outcome, using logistic regression modeling. RESULTS: Of 337 study participants, 70 were healthy, 181 had stable COPD, and 86 had exacerbated COPD. Differences in the microbial characteristics in the participating laboratories were not statistically significant. A cutoff point of 10(2) colony-forming units (CFU) per milliliter or greater for the identification of abnormal positive culture results for PPMs was defined using the 95th percentile in the pooled analysis of healthy individuals. Bronchial colonization of 10(2) CFU/mL or greater by PPMs was found in 53 patients with stable COPD (29%) and in 46 patients with exacerbated COPD (54%) (P<.001, chi(2) test), with a predominance of Haemophilus influenzae and Pseudomonas aeruginosa. Higher microbial loads were associated with exacerbation and showed a statistically significant dose-response relationship after adjustment for covariates (odds ratio, 3.62; 95% confidence interval, 1.47-8.90), but P aeruginosa persisted as a statistically significant risk factor after adjustment for microbial load (odds ratio, 11.12; 95% confidence interval, 1.17-105.82). CONCLUSIONS: One quarter of the patients with COPD are colonized by PPMs during their stable periods. Exacerbation is associated with the overgrowth of PPMs and with the appearance of P aeruginosa in the lower airway, which is associated with exacerbation symptoms independent of load.

Aged↗
PubMed1989

A survey on the microbiological quality of various cheeses in Turkey.

A survey was made at the retail level in the Erzurum, Erzincan and Van markets to study the microbial characteristics of pickled white cheese, Erzincan (Savak) Tulum cheese and Van herby cheese, the most typical cheeses of Turkey. Significant variation was found in their microbiological quality. Microbiological analysis revealed the presence of extremely high numbers of total bacteria, faecal streptococci, other microorganisms including coliforms, Staphylococcus aureus, yeast and mould, lipolytic and proteolytic microorganisms and lactic acid bacteria. A statistical relationship between the number of microorganisms and variety of cheese type was investigated.

Bacteria↗
PubMed2006

Behaviour of Brochothrix thermosphacta in presence of other meat spoilage microbial groups.

The microbial flora of fresh meat stored aerobically at 5 degrees C up to spoilage was enumerated and collected in order to have mixed spoilage bacterial groups to be used in competition tests against Brochothrix thermosphacta. The bacterial groups collected as bulk colonies were identified by PCR-DGGE followed by partial 16S rDNA sequencing. The predominant bacteria associated with the spoilage of the refrigerated beef were B. thermosphacta, Pseudomonas spp, Enterobacteriaceae and lactic acid bacteria (LAB). The interactions between B. thermosphacta and the other spoilage microbial groups were studied in vitro at 5 degrees C. The results showed that a decrease of the growth of B. thermosphacta was evidenced in presence of LAB at 5 degrees C while the bacterium is the dominant organism when inoculated with mixtures of Pseudomonas spp., LAB and Enterobacteriaceae. A better understanding of bacterial meat spoilage interactions may lead to improved quality of fresh meat stored in refrigerated conditions.

Antibiosis↗
PubMed1997

Microbial colonization of closed-system suction catheters used in liver transplant patients.

The microbial colonization and the associated risk of respiratory infection during the application of a multiple-use closed-system suction catheter (CSSC) and a single-use open-system suction catheter (OSSC) on liver transplant patients was evaluated in this preliminary study. The cost differential for the two systems was also compared. Twenty post-orthotopic liver transplant (OLTx) patients who were mechanically ventilated via an endotracheal (ET) tube were studied. Ten subjects were randomly allocated ET suction by the CSSC and 10 with OSSC. Both groups were similar according to age, sex, clinical severity, presence of a naso-gastric tube, use of H2 antagonists and antibiotics used. Standard protocols were followed to intubate and suction the patients and to change ventilatory equipment. Suctioning performed with the CSSC did not significantly increase the risk of microbial colonization of the respiratory tract. Similarly there was no apparent difference in the incidence of nosocomial pneumonia between the two suction systems, based on the microbiological and clinical data. The mean daily cost of using the CSSC compared to the OSSC was 11.6 times higher. This may be balanced by a reduction in nursing time and reduced risk of spread of infection associated with the CSSC.

Adult↗
PubMed2003

The influence of antimicrobial peptides and mucolytics on the integrity of biofilms consisting of bacteria and yeasts as affecting voice prosthetic air flow resistances.

The integrity of biofilms on voice prostheses used to rehabilitate speech in laryngectomized patients causes unwanted increases in airflow resistance, impeding speech. Biofilm integrity is ensured by extracellular polymeric substances (EPS). This study aimed to determine whether synthetic salivary peptides or mucolytics, including N-acetylcysteine and ascorbic acid, influence the integrity of voice prosthetic biofilms. Biofilms were grown on voice prostheses in an artificial throat model and exposed to synthetic salivary peptides, mucolytics and two different antiseptics (chlorhexidine and Triclosan). Synthetic salivary peptides did not reduce the air flow resistance of voice prostheses afterm biofilm formation. Although both chlorhexidine and Triclosan reduced microbial numbers on the prostheses, only the Triclosan-containing positive control reduced the air flow resistance. Unlike ascorbic acid, the mucolytic N-acetylcysteine removed most EPS from the biofilms and induced a decrease in air flow resistance.

Acetylcysteine↗
PubMed2003

Microbial aerosol contamination of dental healthcare workers' faces and other surfaces in dental practice.

The purpose of this study was to focus attention on the need to adopt infection control procedures in dentistry. The quantitative and qualitative bacterial contamination of dental healthcare workers' faces and other surfaces in dental practice was determined. Oral fluids become aerosolized during dentistry and oral microbes have been used as the markers of their spread that may carry blood-borne pathogens.

Air Microbiology↗
PubMed1999

Impedance microbiology: quantification of bacterial content in milk by means of capacitance growth curves.

The impedancimetric method is a technique for the rapid evaluation of milk bacterial content and also of its subproducts. Several authors have made use of culture conductance changes during bacterial growth for quantitative and qualitative assessments of microbial growth. However, interface capacitance curves, Ci, have not been used. In this paper, we quantify bacteria in cow raw milk by following their growth as the above-mentioned capacitance change time course event. With it, bigger growth variations, shorter detection times and a better coefficient of correlation with the plate count method were obtained than those yielded by conductance curves. Calibration was performed by plotting initial known concentrations, IC (CFU/ml), as a function of the time detection theshold (TDT).

Animals↗
PubMed1993

Evaluation of bacterial contamination at separate processing stages in emulsion sausage production.

The contamination with spoilage bacteria at separate production steps during the production of emulsion sausages was evaluated using a special sampling and evaluation method. Heat processed and chilled sausages were aseptically transferred directly to cold storage, cutting down or packing. Upon completion of the particular production step the sausages were vacuum-packed and stored at 8 degrees C. During storage, the microbial growth of the sausages was followed and the area under the plot of aerobic count versus storage time was calculated. No correlation was found between the total aerobic count of unstored samples and bacterial growth during storage, defined as area under growth curves. Furthermore, the count of lactic acid bacteria on unstored sausages was often below the detection limit. However, the area reflected the extent of contamination during processing with bacteria able to grow on cold-stored vacuum-packed sausages. Storage in a cold storage room was identified as a critical point with respect to bacterial recontamination and shelf-life.

Bacteria, Aerobic↗
PubMed2005

Viable count estimates of lag time responses for Salmonella typhimurium M48 subjected to abrupt osmotic shifts.

Generally, relative lag times (RLT; lag time divided by generation time) become extended as conditions become less favourable for growth. Mellefont et al. (2003, 2004) [Mellefont, L.A., McMeekin, T.A., Ross, T., 2003. The effect of abrupt osmotic shifts on the lag phase duration of foodborne bacteria. Int. J. Food Microbiol. 83(3), 281-293; Mellefont, L.A., McMeekin, T.A., Ross, T., 2004. The effect of abrupt osmotic shifts on the lag phase duration of physiologically distinct populations of Salmonella typhimurium. Int. J. Food Microbiol. 92, 111-120] reported that abrupt osmotic shifts of Salmonella typhimurium M48 from optimal to low aw led to unexpectedly small RLTs at low aw. In this study, RLTs resulting from similar osmotic shifts were estimated by viable count (VC) and compared to turbidimetric estimates to test the hypothesis that the 'downturn' in RLT is an artefact of the turbidimetric technique used. No 'downturn' in RLT was observed with VC data and RLTs increased with increasing magnitude of osmotic shift. Anomalous turbidimetric estimates of lag time at low aw were confirmed as the likely source of the 'downturn' in RLT. The abrupt osmotic shifts resulted in a complex pattern of microbial population behaviour. Immediately after transfer from optimal aw to low aw, inactivation of a portion of the population occurred for all the conditions tested. The degree of inactivation became progressively larger with larger shifts in aw. The initial decline in population was followed by a period during which no change in numbers occurred, followed by growth that appeared, in most cases, to be exponential. At the lowest aws tested (< or =0.954), the growth response after the initial decline was at a rate slower than that of exponential phase growth. Due to the use of non-selective media containing pyruvate (to eliminate oxygen radicals), the observed patterns of inactivation, lag and regrowth at most aw conditions are unlikely to result from a temporary loss of culturability, but may represent inactivation of a portion of the population.

Colony Count, Microbial↗
PubMed2003

Listeria monocytogenes: low levels equal low risk.

Because of the public health significance of L. monocytogenes, U.S. regulatory agencies established a policy whereby ready-to-eat foods contaminated with the organism at a detectable level are deemed adulterated. This "zero tolerance" policy, however, makes no distinction between foods contaminated at high and low levels. We have reported elsewhere that a survey of over 31,000 ready-to-eat retail food samples, representing eight product categories, showed an overall prevalence rate of 1.82% for these foods. In this study, we used the food survey data in combination with concurrent data regarding illness in the population consuming the foods, together with other variable factors, to derive a dose-response model. The confidence interval for prevalence was 1.68 to 1.97%. L. monocytogenes levels, which ranged from -2 to 6 log CFU/g, were adequately described by the distribution beta (0.29, 2.68, -1.69, 6.1). An exponential dose-response model was obtained, with an R value (essentially the probability of a single cell causing illness) of 1.76 x 10(-10) for the population at the highest risk. A microbial risk assessment based on the model shows that an alternative to the zero tolerance strategy has a greater risk reduction potential and suggests that a management strategy focusing on the concentration of L. monocytogenes rather than its presence alone may have a greater impact on the improvement of public health by facilitating the development of control measures to limit the maximum levels of L. monocytogenes in foods.

Colony Count, Microbial↗
PubMed2004

Analysis of published sprout seed sanitization studies shows treatments are highly variable.

Consumption of raw sprouts has caused many foodborne illness outbreaks in the last decade, and most outbreaks have been linked to contaminated seeds. Many seed sanitization treatments have been studied as a means to reduce the risk of illness associated with sprouts. Published data on seed sanitization were analyzed collectively to identify factors that influenced the efficacy of seed sanitization and to determine the variability associated with various sanitization processes. Temperature and duration of the sanitization treatment were found to produce a negligible effect on log microbial reductions. Salmonella, Escherichia coli O157:H7, and total aerobic microorganisms were all inactivated at similar rates. Data were fit to triangular or uniform distributions for 16 different chemical treatments. Among the most effective treatments were 8% hydrogen peroxide (uniform distribution [2.5, 4.5]), 20,000 ppm of chlorine (triangular distribution [1, 2.5, 6.5]), and 1% Ca(OH)2 (triangular distribution [0.5, 4, 5]). Chemical treatments where more published data were available showed more variability.

Colony Count, Microbial↗
PubMed2003

Effectiveness of trisodium phosphate against Listeria monocytogenes on excised and nonexcised chicken skin.

The influence of sample type (i.e., excised versus nonexcised chicken skin) on the efficiency of trisodium phosphate (TSP) solutions in reducing Listeria monocytogenes populations and inhibiting their growth during refrigerated storage was studied. Whole chicken legs and excised chicken leg skin fragments inoculated with 10(8) CFU of L. monocytogenes per ml were dipped for 15 min in sterile tap water (control) or in a solution containing 8, 10, or 12% TSP. L. monocytogenes counts were determined after 0, 1, 3, and 5 days of refrigerated storage (2 degrees C). The decontamination effect of TSP was greater for excised skin than for whole legs. Microbial differences between control and TSP-treated samples were significantly larger for excised skin than for whole legs for 9 (75%) of 12 tested combinations of TSP concentrations and storage times. These differences varied from 1.05 +/- 0.26 log10 cycles (day 1) to 3.30 +/- 0.14 log10 cycles (day 5) for nonexcised-skin samples (whole legs) and from 1.54 +/- 0.48 log10 cycles (day 1) to 4.28 +/- 0.86 log10 cycles (day 5) for excised-skin samples. Significantly larger reductions were observed from the third day of refrigerated storage onward. The TSP concentration was a significant factor in the reduction of L. monocytogenes populations. These results suggest that bacteria are more readily accessible to TSP in excised than in nonexcised chicken skin and that the type of sample used to ascertain the efficacy of antimicrobial surface treatments may influence the findings of this type of study.

Animals↗
PubMed2000

Diode laser radiation and its bactericidal effect in root canal wall dentin.

OBJECTIVES: The aim of this study was to investigate the antibacterial effect of a diode laser in deep root canal dentin. BACKGROUND DATA: The microbial colonization of root canal dentin can lead to failures in conventional endodontic treatment if an inadequate bacterial reduction only is achieved through canal treatment and chemical disinfection. METHODS: 100 microm, 300 microm and 500 microm bovine dentin slices obtained by longitudinal sections were sterilized and inoculated on one side with an Enterococcus faecalis suspension. Laser radiation was performed on the opposite side with the diode laser (810 nm) at a setting of 3 W in continuous mode (CW). Radiation was performed using a 400-microm tapered fiber tip at an angle of approximately 5 degrees to the surface over a period of 30 seconds. The output power at the distal end of the tip was 0.6 W. The bacteria were then eluted through vibration and cultured on blood agar plates. The colony count reflected the antibacterial effect of laser radiation as a function of the layer thickness. RESULTS: A mean bacterial reduction of 74% was achieved even with a 500-microm thick slice. CONCLUSION: This investigation indicates that the diode laser radiation reduces the number of bacteria in deep layers of infected root canal wall dentin.

Animals↗
PubMed1998

Efficacy of sterilisation methods and their effect on enamel demineralisation.

The aim of this project was to determine the effectiveness of sterilisation methods for dental enamel for use in intra-oral cariogenicity tests, and their possible effect on the degree of demineralisation of enamel. Bovine incisors were cut vertically into five portions and each assigned to one of five groups. Group 1 was used as a control while the other four groups were subjected, respectively, to gamma irradiation ( congruent with 25kGy), steam autoclaving (121 degrees C for 15 min), sodium hypochlorite (12% w/v for 24h) and povidone-iodine (7.5% w/v for 24h). Total viable counts of microorganisms remaining following sterilisation of the specimens were performed following incubation of the specimens for 24h at 37 degrees C. Caries-like lesions were produced in each specimen using an acidic buffer solution (pH4.5). Sections were cut from each specimen, ground to 80-microgram thickness, and microradiographed. Mineral loss and lesion depth were quantified using transverse microradiography. Statistical analysis was by ANOVA. Dunnett's and Tukey's tests. Microbial growth (Staphylococcus aureus and bacilli) was observed only in control specimens in both brain heart infusion broth and on blood agar plates. The sterilisation methods affected the enamel surface as follows: gamma irradiation (cream discolouration), NaOCl (bleaching), and povidone-iodine (white spot-like lesion). Compared with the control, there was no significant difference in mineral loss and lesion depth with any of the groups, but the numerical values of mineral loss and lesion depth in groups can be ranked as follows: gamma irradiation <povidone-iodine <control <autoclave <NaOCl. In conclusion, the four sterilisation methods were all effective to sterilise enamel, but gamma irradiation proved the most acceptable method for enamel to be used in cariogenicity tests having the least adverse effect.

Acids↗
PubMed1993

Microbial contamination of hydrophilic contact lenses: quantitation and identification of microorganisms associated with contact lenses while on the eye.

Previous studies have demonstrated the presence of microorganisms on hydrogel contact lenses under various usage conditions. We conducted this study to quantify and identify viable bacteria and fungi associated with hydrogel contact lenses while on the eye. We removed the lenses from patients' eyes using aseptic techniques and cultured them to identify loosely adherent, as well as lens bound, microorganisms. Lenses were vortexed in a transfer medium (thereafter called the lens extract) and the lenses were then incubated in an agar sandwich separately from the transfer medium. We cultured 108 lenses (82 daily wear and 26 extended wear) from 49 patients. Bacteria were cultured from 38% (41) of the lenses; for 31 of these 41 lenses bacteria were isolated only from the lens extracts (made by vortexing lenses in a transfer medium), suggesting a transient association with the lenses. No fungi were isolated. Counts of less than 10 colony forming units (CFU)/lens were observed on 89% of the lenses. Staphylococcus epidermidis were the most frequently isolated bacteria. A statistically significant relation was observed between increased CFU/lens and increased lens age for extended wear lenses (p = 0.028).

Adult↗
PubMed1991

Relation of baseline microbial parameters to future periodontal attachment loss.

The relationship between the level of subgingival species at baseline and subsequent attachment loss in a subject was examined. 38 subjects (14-71 years) with prior evidence of periodontal destruction were monitored 2x for pocket depth and attachment level at 6 sites per tooth at baseline and 2 months. A subject was considered to exhibit new attachment loss if 1 or more sites increased 3 mm or more in attachment level in 2 months. Subgingival plaque samples were taken at the baseline visit from the mesial aspect of each tooth (28 sites) using Gracey curettes. Samples were dispersed, diluted and plated on Trypticase soy agar supplemented with 5% sheep blood. After 7 days of anaerobic incubation, the colonies were lifted onto nylon filters, lysed and the DNA fixed to the filters. Digoxygenin-labeled DNA probes were used to enumerate 14 subgingival species. 17 of 38 subjects (44.7%) exhibited new attachment loss in 2 months. The % of the total viable count of each species was averaged for each subject. The species enumerated and the mean % of the total cultivable microbiota averaged across the active and inactive subjects were as follows; B gingivalis 2.3, 1.2; W. recta 1.3, 0.6; B. intermedius I 2.5, 2.0; B. forsythus 1.5, 1.2; A. actinomycetemcomitans serotype a 1.1, 0.8; F. nucleatum ss vincentii 1.1, 1.0; S. intermedius 2.0, 1.9; P. micros 1.5, 1.5; B. intermedius II 1.6, 1.7; A. actinomycetemcomitans serotype b 0.4, 0.6; S. sanguis I 1.8, 2.1; S. sanguis II 2.7, 3.0; V. parvula 3.9, 4.2; C. ochracea 0.9, 1.8.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed2005

In vitro method to assess the antimicrobial activity and potential efficacy of novel types of wound dressings.

AIMS: To develop a simple, reproducible in vitro static diffusion method using cellulose disks and defined species to test antimicrobial efficacy of wound dressings. METHODS AND RESULTS: Cellulose disks were inoculated by immersion in cell suspensions of target species Staphylococcus epidermidis, Candida albicans and Fusobacterium nucleatum. Test and control wound dressings were cut into equal sized squares (25 x 25 mm) and applied to the surface of 10-mm thick tryptone yeast extract agar on test beds. Following a 2-h equilibration period, inoculated cellulose disks were inserted (one per dressing) at the interface between dressing and agar surface and a small weight applied over each square. At various sampling times, disks were removed and surviving cells enumerated by viable counts. Disk to disk variation for microbial loading was assessed using S. epidermidis for both initial (n = 16) and standard treatment (n = 16) conditions. The coefficient of variation was low (<5%) indicating good reproducibility for cell loading and treatment position on the test bed. Replicate assays (n = 6) using S. epidermidis and oxyzyme gels produced similar kill rates with low scatter (R2 > 0.9) indicating good reproducibility between assays. Significant differences (P < 0.05) in kill rates were observed for different target species, types of dressing and test bed conditions (+/-blood and nutrients). CONCLUSIONS: The method is reproducible and useful in tracking the death kinetics of test species, enabling the comparison of different types of dressing. SIGNIFICANCE AND IMPACT OF THE STUDY: The reported method has significant advantages over established test procedures; it can be applied equally across a wide range of target species (including anaerobes and yeasts), a wide range of conditions, and different types of surface dressings, including those relying upon oxygen diffusion.

Anti-Infective Agents, Local↗
PubMed2001

Differences in the microflora of scarified and unscarified seeds of Karwinskia humboldtiana (Rhamnaceae).

Seeds of Karwinskia humboldtiana obtained from a 1997 collection in the locality of Villa de Gracía Nuevo (León, Mexico) were contaminated with spores of filamentous fungi, bacteria and yeasts. The concentration of microorganisms in unscarified seeds ranged from 3.0 x 10(3) to 7.5 x 10(3) CFU/g. Predominant were bacterial isolates of the genera Aeromonas sp., Bacillus, and Pseudomonas; from filamentous fungi were identified Alternaria, Aspergillus niger, Cladosporium sp., Fusarium sp., Mucor sp., Penicillium commune, Trichothecium sp.; from yeasts Rhodotorula sp. and Saccharomyces cerevisiae. Seed scarification significantly reduced the microbial contamination. Of the original fungal isolates, only two were identified on scarified seeds, viz. Cladosporium sp. and Saccharomyces cerevisiae; although a relatively high incidence of a unidentifiable of Penicillium sp. was found, the bacterial spectrum was not altered. Treatment of scarified seeds with Vitavax 200 WP and Pomarsol Forte 80 WP (3 mg/g seeds) augmented germination by 10-19% compared to treated unscarified seeds, and by 16-31% compared to untreated unscarified seeds.

Bacteria↗