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At least 19 recordsLinked to original sources
PubMed1990

Therapeutic efficacy of granulocyte colony-stimulating factor alone and in combination with antibiotics against Pseudomonas aeruginosa infections in mice.

The therapeutic efficacy of granulocyte colony-stimulating factor (G-CSF) against an experimental intramuscular infection induced by Pseudomonas aeruginosa in mice was confirmed. Bacterial growth in the infected thigh muscle was suppressed by G-CSF treatment. The change in the number of peripheral blood polymorphonuclear leukocytes (PMN) after bacterial challenge was investigated. The results showed that G-CSF could stimulate stronger defense mechanisms after stimulation by bacterial challenge. In the G-CSF-treated group, more clusters of matured PMN were observed in the infected thigh muscle 6 h after bacterial challenge. Next, the correlation between the number of PMN in the blood at the time of infection and the therapeutic efficacy of antibiotics was investigated. The therapeutic efficacy of ceftazidime, a beta-lactam antibiotic, was affected by the number of blood PMN at the time of infection. In particular, a decrease of peripheral blood PMN at the time of infection resulted in a dramatic decrease in the efficacy of ceftazidime. The reduction in leukopenia by G-CSF remarkably strengthened the therapeutic effect of antibiotics in mice.

Animals↗
PubMed1991

Mechanism of protective effect of recombinant human granulocyte colony-stimulating factor (rG-CSF) on Pseudomonas infection.

Decrease in resistance to systemic Pseudomonas infection in cyclophosphamide (CPA)-induced neutropenic mice was prevented by injections of recombinant human granulocyte colony-stimulating factor (rG-CSF). In order to explore mechanism of the prevention of CPA-induced decrease in the anti-infectious resistance by rG-CSF, CPA-treated and then rG-CSF-injected mice were inoculated i.p. with P. aeruginosa, and growth of the infecting bacteria and infiltration of leukocytes in the peritoneal cavity were determined. In the mice who had received 4 daily s.c. injections of rG-CSF from the day after CPA-injection, a large number of neutrophils were mobilized into the peritoneal cavity in response to the bacterial inoculation and growth of the infecting Pseudomonas in the cavity was markedly inhibited, whereas in CPA-induced neutropenic mice few neutrophils were mobilized and the infecting bacteria proliferated vigorously in the peritoneal cavity. These results suggest that administration of rG-CSF prevents CPA-induced neutropenia and neutrophils circulating at normal level in the number are normally mobilized into the peritoneal cavity in response to Pseudomonas inoculation, and that the mobilized neutrophils inhibit proliferation of the infecting Pseudomonas.

Animals↗
PubMed1990

Protective effect of recombinant human granulocyte colony-stimulating factor (rG-CSF) against various microbial infections in neutropenic mice.

Protective effect of recombinant human granulocyte colony-stimulating factor (rG-CSF) on microbial infections was studied in cyclophosphamide (CPA)-induced neutropenic mice. The neutropenic mice showed severely decreased resistance against systemic infections of Pseudomonas aeruginosa, Escherichia coli, Serratia marcescens, Staphylococcus aureus, and Candida albicans. When such mice were injected subcutaneously with rG-CSF on four consecutive days beginning the day after CPA injection, the decreased anti-microbial resistance of the mice was restored to the level of that in normal mice. The anti-infective effect of rG-CSF was dose-dependent and the 50% effective doses (ED50) in various microbial infections tested were 1-10 micrograms/kg/day. The results suggest that rG-CSF is useful for protection of neutropenic patients from microbial infections.

Animals↗
PubMed1992

Subgingival temperature (III). Relation to microbial counts.

The present investigation examined the relationship of selected bacterial species and subgingival temperature. 35 subjects were measured at 6 sites per tooth for clinical parameters and subgingival temperature. Measurements were repeated for 21 subjects at 2 month intervals providing a total of 66 subjects visits. At each visit, subgingival plaque samples were taken from the mesial aspect of each tooth and anaerobically dispersed, diluted and plated on non-selective media. After anaerobic incubation, colonies were lifted to nylon filters and specific species detected using digoxigenin-labeled whole chromosomal DNA probes. Species enumerated were; A. actinomycetemcomitans serotypes a and b, B. forsythus, B. gingivalis, B. intermedius I and II, C. ochracea, F. nucleatum ss. vincentii, P. micros, S. intermedius, S. sanguis I and II, V. parvula and W. recta. Total viable counts and counts of Capnocytophaga sp. were determined directly from the primary isolation plates. A total of 1581 samples were evaluated. Subject visits with higher mean subgingival temperatures had significantly higher mean %s of B. intermedius I and P. micros, and lower mean %s of Capnocytophaga sp. Sites with higher subgingival temperatures had elevated proportions of B. intermedius I and II, A. actinomycetemcomitans serotype a and B. gingivalis more frequently than sites with lower temperatures, while Capnocytophaga sp. were elevated more often at cooler sites. 43 of the subject visits had follow up attachment level measurements at 2 months. The 1026 microbial samples and the subgingival temperature measurements from these visits were related to longitudinal attachment change.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMedDate not supplied

Quantifying heterogeneity: flow cytometry of bacterial cultures.

Flow cytometry is a technique which permits the characterisation of individual cells in populations, in terms of distributions in their properties such as DNA content, protein content, viability, enzyme activities and so on. We review the technique, and some of its recent applications to microbiological problems. It is concluded that cellular heterogeneity, in both batch and continuous axenic cultures, is far greater than is normally assumed. This has important implications for the quantitative analysis of microbial processes.

Bacteria↗
PubMed1991

Performance and ruminal function development of young calves fed diets with Aspergillus oryzae fermentation extract.

Neonatal Holstein heifer (n = 72) and bull (n = 40) calves were used to study the effects of Aspergillus oryzae fermentation extract (Amaferm) on their performance and on rumen development. The starter diets were formulated to achieve Amaferm consumption of 0, .5, 1, or 3 g per calf daily. Calves were fed milk daily and allowed to consume starter and a mixture of alfalfa and bromegrass hay ad libitum. Weaning was when calves consumed 550 g of starter on 2 consecutive d. Weight gain and feed consumption were recorded weekly. Forty of the heifer calves, 10 from each treatment, were selected randomly to study the effects of Amaferm on ruminal fermentative development. Ruminal fluid samples were collected for pH, ruminal fermentation products, and for bacterial enumerations. Overall, Amaferm-supplemented calves were weaned 1 wk earlier than unsupplemented calves. They had higher total VFA, propionate, and acetate concentrations in the rumen than unsupplemented calves. Total anaerobic, hemicellulolytic, and pectinolytic bacterial counts were higher; cellulolytic bacterial counts tended to be higher for the Amaferm-supplemented calves than for controls. In general, Amaferm-supplemented calves had greater ruminal microbial activity than those not fed Amaferm.

Animal Feed↗
PubMed1991

Bacteriological safety of cook-chill food at the Royal Free Hospital, with particular reference to Listeria.

Cook-chill food prepared by the Catering Department of the Royal Free Hospital was examined over an 8-month period commencing October 1989. Total aerobic viable counts (TAVCs) were performed on 200 food specimens which were also examined for Listeria using selective enrichment culture. Ten of 200 food samples tested had TAVCs greater than 10(5) colony forming units (cfu) g-1, and nine of these were from non-vegetarian (meat) dishes. Although most of the food prepared by cook-chill had microbial loads within the limits recommended by current Department of Health guidelines (i.e. less than 10(5) cfu g-1), our findings for the non-vegetarian dishes suggest that extra caution is required when preparing such food. Listeria were not isolated from any food sample. In a survey of listeria faecal carriage, Listeria monocytogenes was isolated from only two of 100 faeces specimens obtained from patients.

Colony Count, Microbial↗
PubMed1992

Luminometric measurement of population activity of genetically modified Pseudomonas fluorescens in the soil.

Genetically modified cells of Pseudomonas fluorescens, chromosomally marked with genes for bioluminescence, were inoculated into sterile soil microcosms. During incubation for 90 days, viable cell concentration did not change significantly but light output, measured by luminometry, decreased, indicating reduced metabolic activity due to lack of substrates. Amendment with nutrients resulted in parallel increases in both luminescence and dehydrogenase activity. Luminometry therefore enables rapid monitoring of the activity of populations of luminescence-marked microbial inocula in the soil, with greater sensitivity and selectivity than traditional techniques.

Bacteriological Techniques↗
PubMed2025

The efficacy of a filtered handheld far-ultraviolet disinfection device for decontamination of high-touch surfaces in healthcare settings: a genomic bacterial analysis.

BACKGROUND AND OBJECTIVES: Enhanced environmental disinfection is linked to reduced hospital-acquired infection rates. In this study, we aimed to evaluate the efficacy of an emerging disinfection technology, a filtered far-UV-C handheld (FFUHH) device, for reducing bacterial loads on high-touch surfaces in shared clinical workrooms, and to isolate, identify and characterize clinically significant environmental pathogens. METHODS: We compared samples from high-touch items (dictation device, mouse, armchair, desk, and keyboard) before and after FFUHH treatment. Samples were collected weekly: contact plates for colony counts and swabs before and after intervention on standardized adjacent areas for each surface, respectively. The swabs were enriched and cultured on selective media to isolate pathogens. Environmental samples, as well as clinical samples collected from patients during the study period, were validated using MALDI-TOF and whole genome sequencing. RESULTS: Among the 440 collected plates (220 before and 220 after treatment), the highest mean colony count pre-treatment was detected from armchairs, and the lowest from keyboards. The mean reduction of colony-forming units ranged 53% and 83% and was statistically significant (P < 0.05) across all surfaces except for the keyboard. We characterized multidrug-resistant Staphylococcus epidermidis ST5 and ST16 strains, a carbapenem-resistant Acinetobacter baumannii, and a Klebsiella pneumoniae genetically related to a clinical isolate with a rare sequence type not previously detected in our institution. CONCLUSION: The FFUHH effectively reduced the microbial burden on high-touch surfaces. It can offer an advantage for surface disinfection and an alternative to routinely used biocides.

Humans↗
PubMed1992

Efficacy of preprocedural rinsing with an antiseptic in reducing viable bacteria in dental aerosols.

This double-blind, controlled, cross-over, clinical study evaluated the effect of preprocedural rinsing with an antiseptic mouthrinse on the level of recoverable viable bacteria in an aerosol generated during a typical dental procedure. Eighteen subjects participated. Following 24 hours of abstention from all oral hygiene procedures, subjects received a 10-minute ultrasonic scaling of a randomly selected one-half of their mouth which served as the unrinsed control. They were then randomly assigned either antiseptic mouthwash or a control rinse and rinsed with 20 ml for 30 seconds, after which the remaining half mouth (experimental side) was scaled ultrasonically for 10 minutes. During each 10-minute scaling period aerosolized bacteria were collected on a sterile filter using a modified vacuum air-sampling device. Microbes captured on the sterile filter were quantitated by overlaying the filters onto trypticase soy agar, incubating the filters aerobically at 37 degrees C for 24 to 72 hours, and counting the resulting colony forming units (CFU). Preliminary experiments had confirmed that neither the collection method nor residual antiseptic mouthwash in the aerosol adversely affected the number of viable bacteria recovered from the filter. Rinsing with the antiseptic mouthwash produced a 94.1% reduction in recoverable CFUs compared to the non-rinsed control, while the control rinse produced a 33.9% reduction. The difference between the mouthwash and control was statistically significant (P < .001). This study indicates that preprocedural rinsing with an antiseptic mouthwash can significantly reduce the microbial content of aerosols generated during ultrasonic scaling and may have potential in-office use as part of an infection control regimen.

Adult↗
PubMed1992

Electron-microscopic description of accretions occurring on tips of infected and non-infected central venous catheters.

OBJECTIVE: The purpose of the study was do describe the architecture of accretions occurring on the tips of central venous catheters (CVC). DESIGN: A conservative procedure was used followed by two different techniques of electron microscopy. SETTING AND PATIENTS: the study included 19 catheters which have been used on intensive cared adults, and which were chosen among those of parallel 300 CVC study. MEASUREMENTS AND RESULTS: CVC were considered sterile, contaminated, colonized or infected according to microbiological and clinical criteria. CVC were found to remain much cleaner than in past descriptions. When present, accretions were located on the olive-shaped end, and displayed stratified structures with three types of material: amorphous material, thrombus components and inflammatory cells. Bacteria were not seen, even on culture positive CVC. Candida albicans was found on one CVC in the cytoplasm of granulocytes, and made no direct contact with the plastic surface. CONCLUSION: This technique should contribute to the understanding of the pathobiology of CVC infection and provide information proving or precluding the involvement of microbial adherence to polymers in vivo.

Anti-Bacterial Agents↗
PubMed1992

Day-long reduction of oral malodor by a two-phase oil:water mouthrinse as compared to chlorhexidine and placebo rinses.

Few scientific investigations have addressed the ability of mouthrinses to reduce oral malodor for periods longer than 3 hours. In the present report, we have employed simple, recently described techniques to assess the day-long reduction in oral malodor of a novel 2-phase oil:water mouthrinse (TPM), as compared to a corresponding placebo rinse, and to a commercial 0.2% chlorhexidine mouthrinse. Sixty dental students were divided randomly into 3 groups, and instructed to use one of the rinses prior to bedtime and the following morning. Measurements carried out in the late afternoon, about 8 to 10 hours following rinsing, were compared with baseline measurements carried out in the late afternoon of the previous day. Volatile sulphide levels were measured using a portable industrial sulphide monitor. Microbial levels were estimated using a simple rinsing technique employing sterilized milk. These quantitative techniques were corroborated by organoleptic (hedonic) ratings of a single odor judge. Both TPM and chlorhexidine brought about significant decreases in volatile sulphides (P less than 0.05) as compared to the placebo group. These results were corroborated by the organoleptic data. Similarly, both chlorhexidine and TPM were highly effective in reducing microbial levels as measured by the rinsing technique, in comparison to the placebo group. Chlorhexidine appeared to be more effective than TPM in all measurement categories, although only in the case of microbial activity was there a significant (P less than 0.05) difference between the two groups.

Bacteria↗
PubMed1992

A novel electrical method for the prevention of microbial colonization of intravascular cannulae.

An electrical device designed to prevent microbial attachment to plastic intravascular cannulae is described. The device produced an electrical current (10 microA) in both carbon-impregnated and 'Hydrocath' cannulae. In-vitro models were utilized to demonstrate that the current can block several mechanisms by which microorganisms gain initial access to intravascular devices, including extra- and intra-luminal routes. The electrical system prevented organisms from traversing along both the external and internal surfaces of the cannulae. Effective prevention of cannula colonization was demonstrated subsequent to challenge with Staphylococcus epidermidis, Staphylococcus aureus, Enterococcus faecalis, Proteus mirabilis, Pseudomonas aeruginosa and Candida albicans. The findings suggest that the electrical device may offer in-vivo cannula protection from microbial attachment and colonization, thereby reducing the potential for infection.

Bacterial Adhesion↗
PubMed1992

Microbial colonization and sperm--mucus interaction: results in 1000 infertile couples.

After screening a large series of infertile patients (n = 1000 couples), potentially pathogenic microorganisms were identified in genital secretions of the majority of couples. None of the patients displayed signs or symptoms of infection of the lower genital tract. In semen specimens and cervical swabs, mycoplasmas were found in 18 and 12%, potentially pathogenic aerobic bacteria in 50 and 31%, additionally commensal aerobes in 38% and 25%, respectively. The microbial pattern showed great variability with polymicrobial growth most common. The rate of cultures positive for potentially pathogenic anaerobes was markedly influenced by the transport conditions. In endocervical material, Herpes simplex virus (HSV) was identified in 4.5%. Yeasts were found in the posterior vaginal fornix in 10%. Concerning both partners, there were only 10 couples (1%) from whom microorganisms in genital secretions could not be isolated, not including lactobacilli in females. This high prevalence of microbes and the low number of leukocytes indicate colonization rather than infection. When the microbial findings from both partners were analysed with regard to the outcome of sperm-cervical mucus penetration testing in vitro, which was performed simultaneously, no significant correlation was found. Furthermore, microbial prevalence did not differ between couples with 'explained' and 'unexplained' infertility. The results of this study demonstrate that in patients without symptoms of genital tract infection, microbial colonization is of minor importance for sperm--mucus interaction and that extensive microbial screening should be preferentially performed in cases of poor sperm and/or mucus function.

Adult↗
PubMed1992

Comparative study on the antimicrobial effects of Hexomedine and Betadine on the human skin flora.

Studies were carried out to detect the modifications, if any, on the peri-umbilical flora of six healthy volunteers after two or three daily applications of Hexomedine solution (HEX) and Betadine solution (PVI) repeated for five consecutive days. A standardized scrubbing method was used for bacterial sampling. Surviving bacteria were selected with both selective and non-selective media, and then identified by gas chromatographic fatty acid analysis. Both antiseptics were highly effective, showing both immediate and residual antimicrobial activities. The use of HEX led to a slight increase in Gram-positive cocci and a small decrease in coryneforms, but PVI produced a marked increase in Gram-positive cocci and a sharp decrease in coryneforms. The two antiseptics, however, caused no major alteration in the cutaneous microbial population. Indeed, neither the overgrowth of Gram-negative bacilli nor the emergence of resistant species was observed.

Adult↗
PubMed1992

Microbial contamination of brushes used for preoperative shaving.

Microbial contamination of brushes used for preoperative shaving was investigated. Of the 24 brushed examined, 18 were contaminated with 10(6)-10(9) colony forming units (cfu) per brush. Non-fermentative Gram-negative bacilli such as Pseudomonas aeruginosa and Xanthomonas maltophilia, and yeast-like fungi such as Candida parapsilosis were the primary contaminants. The mean bacterial count on the skin after the use of contaminated brushes (having a mean bacterial count 2.2 x 10(8) cfu) in 14 subjects was 4.6 x 10(5) cfu 25 cm-2, which was about 100 times (p less than 0.001) the control level. Contaminated brushes could not be disinfected with 80% ethyl alcohol, 0.1% sodium hypochlorite or 0.5% chlorhexidine. These findings suggest that the use of brushes should be avoided for preoperative shaving with a razor, and that sterile gauze and shaving foam should be used instead of a brush and soap.

Candida↗