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PubMed2005

Influence of age and duration of infection on bacterial load and immune responses to Helicobacter pylori infection in a murine model.

Using a murine model, we previously showed that Helicobacter pylori infects and colonizes offspring via maternal transmission during the nursing period. The aim of this study was to investigate the influence of age and duration of infection on inflammatory and immune responses to H. pylori in infant and adult mice. During the breast-feeding period, the number of bacteria was significantly suppressed in 1-week-old mice infected with H. pylori at an early stage of nursing, compared with adult mice, suggesting that breast-milk induces such low colonization. In addition, these mice had weaker gastric inflammation, especially Th1 cytokine and humoral responses than in mice infected with H. pylori after weaning in spite of elevated levels of Th1 cytokines. Although infant mice showed low inflammatory responses against H. pylori, they produced H. pylori-specific antibodies following vaccination with oral or parenteral adjuvant. Our results suggest the importance of age at the time of primary infection on bacterial load, gastric inflammation and humoral responses in a murine model of H. pylori infection.

Aging↗
PubMed1989

Antibody response to phenolic glycolipid I and Mycobacterium w antigens and its relation to bacterial load in M. leprae-infected mice and leprosy patients.

Twenty-six inbred BALB/cBy mice were infected with live Mycobacterium leprae by injecting 6 x 10(3) bacilli in the hind footpad. Bleeds were collected at monthly intervals. After 6 months, acid-fast bacilli (AFB) were harvested monthly from the footpad of mice. The sera were analysed in enzyme immunoassay for antibodies against phenolic glycolipid I (PGL-I) of M. leprae and antigens of Mycobacterium w (M. w); 21 out of 26 (80.7%) mice demonstrated the presence of antibodies against PGL-I and M. w . Anti-M. w antibodies appeared slightly earlier than did anti-PGL-I antibodies. The titre of anti-M. w antibodies was higher than that of anti-PGL-I antibodies. The mice giving a positive antibody response had more than 7 x 10(5) AFB/footpad. The coefficient of correlation (r) between the number of AFB and antibody titres at the time of harvest was 0.566 for PGL-I and 0.628 for M. w. The value of r for bacterial index and antibody titres in 188 leprosy patients was 0.510 for PGL-I and 0.418 for M. w; these values were statistically significant (P < 0.001). The decrease in bacterial index and antibody titres in treated lepromatous leprosy patients correlated with increase in the duration of chemotherapy. The measurement of anti-PGL-I antibodies of IgM class may serve as an adjunct to skin biopsy and skin-slit smear for serial monitoring of the bacterial load in the course of chemotherapy in leprosy control programmes.

Animals↗
PubMed2004

Attenuation of the bacterial load in blood by pretreatment with granulocyte-colony-stimulating factor protects rats from fatal outcome and brain damage during Streptococcus pneumoniae meningitis.

A model of pneumococcal meningitis in young adult rats receiving antibiotics once the infection was established was developed. The intent was to mimic clinical and histopathological features of pneumococcal meningitis in humans. The primary aim of the present study was to evaluate whether medical boosting of the peripheral neutrophil count affected the outcome of the meningitis. The risk of terminal illness over the first 7 days after infection was significantly reduced for rats who had elevated peripheral white blood cell counts after receiving granulocyte-colony-stimulating factor (G-CSF) prior to the infection compared to that for untreated rats (P = 0.039 by the log rank test). The improved outcome was associated with reduced signs of cerebral cortical damage (P = 0.008). Furthermore, the beneficial effects of G-CSF were associated with reduced bacterial loads in the cerebrospinal fluid (median, 1.1 x 10(5) versus 2.9 x 10(5) CFU/ml; P = 0.023) and in blood (median, 2.9 x 10(2) versus 6.3 x 10(2) CFU/ml; P = 0.024), as well as attenuated pleocytosis (median, 800 x 10(6) versus 1,231 x 10(6) cells/liter; P = 0.025), 24 h after the infection. Conversely, initiation of G-CSF therapy 28 h postinfection did not alter the clinical or histological outcome relative to that for non-G-CSF-treated rats. The magnitude of bacteremia and pretreatment with G-CSF were found to be prognostic factors for both outcome and brain damage. In summary, elevated neutrophil levels prior to the development of meningitis result in reduced risks of death and brain damage. This beneficial effect is most likely achieved through improved control of the systemic disease.

Animals↗
PubMed2003

Evidence for localized bacterial loading as the cause of chronic beach closings in a freshwater marina.

We conducted a comprehensive regional spatial assessment of bacterial water quality in order to determine the points of entry of fecal pollution into a swimming beach area on Lake Michigan that historically has had numerous water quality advisories for elevated levels of Escherichia coli (E. coli). Intensive, consecutive-day water samples were collected during dry and rainy conditions across multiple shoreline and offshore sites, and E. coli levels were enumerated from these samples. For both dry and rainy days, shoreline sites demonstrated significantly higher E. coli levels than offshore regions. We found that offshore (10-150m from shore) E. coli levels did not exceed 235CFU/100ml in more than 5% of the samples collected for 19 surveys (n=209). In contrast, samples taken at the beach area exceeded 235CFU/100ml in 66% of the samples collected for 43 shoreline surveys (n=675). Locally high E. coli levels coincided with bird presence and stormwater at the swimming beach located within the marina, and were unrelated to E. coli levels in connecting harbor waters. We conclude that beach water quality may be impacted by local, persistent contamination, which may confound routine beach monitoring and prevent the detection of regional pollution from other sources.

Animals↗
PubMed2005

DNA-loaded bacterial ghosts efficiently mediate reporter gene transfer and expression in macrophages.

There is a demand for efficient and safe DNA delivery vehicles mediating gene transfer and expression. We present bacterial ghosts as a novel platform technology for DNA delivery and targeting of macrophages. Bacterial ghosts are cell envelopes of gram-negative bacteria that are devoid of the cytoplasmic content. Escherichia coli ghosts were loaded with plasmid DNA and linear double-stranded DNA. Confocal laser scanning microscopy and flow cytometry confirmed that the DNA localized to the inner lumen of bacterial ghosts and was not associated with the outer surface of the bacteria. Up to approximately 6000 plasmids could be loaded per single ghost and the amount of loaded DNA correlated with the DNA concentration used for loading. E. coli ghosts loaded with plasmids encoding the enhanced green fluorescent protein (EGFP) targeted efficiently murine macrophages (RAW264.7) and mediated effective gene transfer. The EGFP was expressed by more than 60% of the macrophages as measured by flow cytometry detecting the green fluorescence and immunocytochemical staining with antibodies specific for EGFP.

Animals↗
PubMed2002

The effect of drying dental unit waterline biofilms on the bacterial load of dental unit water.

AIM: To evaluate drying of the dental unit waterlines (DUWL) as a new method of controlling the bacterial biofilm therein and thereby to reduce the number of living bacteria in dental unit water. SETTING: 18 dental units were incorporated into the study. Six units constituted the experimental units, which were emptied for stagnant water in the DUWL every night; six units were chlorinated every night (positive controls), and six units were left untreated (negative controls). OUTCOME MEASURE: Water samples from the ultrasonic scaler were examined microbiologically according to the guidelines from the Danish Standard Association and the number of colony forming units (cfu) per ml of water was determined. RESULT: Drying of DUWL did not reduce the number of cfu per ml in dental unit water below the levels found in DUWL left untreated. CONCLUSION: The drying of the waterlines for about 16 hours per day during a 19-day period did not result in reduced counts of bacteria in water samples from the experimental units.

Bacteria↗
PubMed1972

Steam versus hot-water scalding in reducing bacterial loads on the skin of commercially processed poultry.

A comparison of two types of scalders was conducted to determine their effectiveness in reducing bacterial contamination of poultry carcasses. A conventional hot-water scalder and a prototype model of a steam scalder were tested under commercial conditions. Total plate counts from steam-scalded birds were significantly lower than the counts of water-scalded birds immediately after scalding and again after picking. No differences in the two methods could be found after chilling. Coliform counts from steam-scalded birds were significantly lower than the counts from water-scalded birds immediately after scalding. No significant differences in coliform counts were detected when the two scald methods were compared after defeathering and chilling.

Bacteria↗
PubMed2006

Evaluation of the efficacy of a peroxygen disinfectant-filled footmat for reduction of bacterial load on footwear in a large animal hospital setting.

OBJECTIVE-To compare the efficacy of a peroxygenbased disinfectant used in footbaths with the efficacy of the same disinfectant used in footmats for reducing bacterial contamination of footwear in a large animal hospital. DESIGN-Prospective study. SAMPLE POPULATION-Bacteria recovered from the soles of rubber boots after experimental microbial contamination and exposure to disinfectant solutions or water (water-treated control boots) or no treatment (untreated control boots). PROCEDURES-Investigators contaminated boots by walking through soiled animal bedding. Swab samples were collected from the sole of 1 untreated boot (right or left); the other boot was treated as investigators stepped through a disinfectant-filled footbath, a disinfectant-filled footmat, or water-filled footmat. Samples were collected 10 minutes after each treatment. Differences in numbers of bacteria recovered from treated and untreated boots were analyzed. RESULTS-Mean bacterial counts from peroxygentreated boots were 1.3 to 1.4 log(10) lower (95.4% to 99.8%) than the counts from untreated boots. Results were similar for footmat- and footbath-treated boots. In contrast, there were no statistically detectable differences in mean bacterial counts in samples collected from water-treated or untreated boots. CONCLUSIONS AND CLINICAL RELEVANCE-Results suggest that footmats and footbaths containing peroxygenbased disinfectant are effective in reducing bacterial contamination on the soles of boots when used in conditions representative of large animal hospitals. Similar results were achieved with use of either footmats or footbaths. The use of footbaths and footmats containing effective disinfectants may help decrease the risk for spread of nosocomial infection but should not be expected to sterilize footwear.

Animals↗
PubMed1997

Clinical assessment of the bacterial load of Helicobacter pylori on gastric mucosa by a new multi-scaled rapid urease test.

The present study tests the efficacy of the multi-scaled urease test (MUT) in detecting Helicobacter pylori infection and determines whether the MUT can predict the bacterial density on histology. A total of 111 sets of gastric specimens were obtained from patients with dyspepsia but without recent bleeding. Two biopsies were taken as closely as possible in each set. One sample was used for the MUT (Hp fast; GI Supply, Camp Hill, PA, USA), while the other was used to determine the histological density of H. pylori by modified Giemsa stain (grade 0-5). The results of MUT were interpreted as negative if the colour was yellow or bright green (reaction score 0) and positive if the colour was green, light blue, or blue (reaction score 1, 2 and 3, respectively). The reaction scores of MUT were recorded sequentially at 15 and 30 min and 1, 4 and 24 h. On the basis of histological confirmation, MUT had a sensitivity of 89.6%, a specificity of 88.2%, a positive predictive value of 94.5% and a negative predictive value of 78.9%. Focusing on specimens with the presence of bacteria under histology, 77 specimens were divided into five subgroups by grades of density of H. pylori (HPD1-5). The reaction scores had become sequentially elevated from 30 min through to 24 h in each subgroup. For subgroups HPD4 and 5, the positive rates of MUT were 70.6 and 66.6%, respectively, as early as 30 min and progressed to 100% within 4 h. In contrast, the positive rate for the HPD1 subgroup was 16.6% at 4 h and increased to only 62.5% at 24 h. In subgroups HPD 2 and 3, the positive rates were less than 30% at 30 min, but became more than 66.6% at 4 h and were 100% at 24 h. The early (i.e. mean value of reaction scores before 4 h) and late (24 h) mean reaction scores disclosed two elevated trends as the density of H. pylori increased (early: 0.2, 0.7, 0.8, 1.5, 1.2; late: 1.4, 2.3, 2.6, 3.0, 3.0; P < 0.05). In conclusion, MUT is a reliable method for the diagnosis of H. pylori infection. It can also indirectly predict the density of H. pylori on histology.

Biopsy↗
PubMed2002

Biogenic amines in chicken meat products in relation to bacterial load, pH value and sodium chloride content.

Exogenous biogenic amines may present food poisoning hazards, especially when coupled with additional risk factors. In recent years, consumption of poultry meat and poultry meat products has increased. Therefore, the goals of this work were to estimate biogenic amines in chicken meat products and to find a correlation to bacterial quality, pH value and/or NaCl content. A total number of 60 random samples of chicken frankfurter, luncheon and keshta were collected from Cairo and Assiut supermarkets and groceries. The samples were analyzed for estimation of histamine, tyramine, cadaverine and puerscine. The results were in low levels and varied in each product. The bacterial quality was evaluated with respect to total colony, Enterobacteriaceae, coliforms, Lactobacillaceae and Pseudomonas aeruginosa counts. These amineproducering bacteria were detected in low amounts. Such findings as well as pH value and NaCl content correlated with amines levels.

Animals↗
PubMed2002

Study of the bacterial load in a gelatine production process focussed on Bacillus and related endosporeforming genera.

Gelatine is an animal protein with many industrial applications. Previous studies pointed out that endosporeforming bacteria, belonging to the genus Bacillus or related genera, might contaminate and survive the production process of gelatine, leading to products of low quality and safety. The aim of this study is to determine the bacterial diversity of contaminants isolated from a gelatine production chain with emphasis on aerobic endosporeforming bacteria. Contaminants were isolated from samples taken at five crucial points along two different production lines of a gelatine production process and from water supplies used for extraction and cooling. Gaschromatographic methyl ester analysis of fatty acids was performed to differentiate isolates at the genus level. Apart from members of the genus Bacillus or related endosporeforming genera, also members of Salmonella, Kluyvera, Staphylococcus, Burkholderia, Enterococcus, Pseudomonas, Yersinia, Streptococcus and Brevundimonas could be detected. Isolates identified as belonging to Bacillus and related endosporeforming genera were further characterised by gelatinase tests, rep-PCR and 16S rDNA sequencing. All these isolates showed the ability to liquefy gelatine. Endosporeforming isolates were assigned to Bacillus licheniformis, B. fumarioli, members of the B. cereus group, B. badius, B. coagulans, B. subtilis, Brevibacillus agri, Alicyclobacillus acidocaldarius and a yet undescribed Paenibacillus species.

Bacillus↗
PubMed1991

Bacterial load and inflammatory reaction in the bowel wall after colonic obstruction. An experimental study in rats.

To quantify the inflammatory reaction to obstruction, alkaline phosphatase and myeloperoxidase activities were measured in specimens of colonic wall from 60 rats. Twenty rats had undergone laparotomy and band obstruction, 20 laparotomy without obstruction and 20 had no operation. The mean activities of both enzymes were increased proximal but not distal to the obstruction, that of alkaline phosphatase significantly so. Despite increase in the number of bacteria, both proximal and distal to the obstruction, no signs of bacterial invasion of the bowel wall were seen either on histological examination or culture. These findings indicate that mechanical factors may be more important than bacteria in causing the increased inflammatory reaction in bowel wall proximal to an obstruction.

Alkaline Phosphatase↗
PubMed1997

Ginseng treatment reduces bacterial load and lung pathology in chronic Pseudomonas aeruginosa pneumonia in rats.

The predominant pathogen in patients with cystic fibrosis (CF) is Pseudomonas aeruginosa, which results in a chronic lung infection associated with progressive pulmonary insufficiency. In a rat model of chronic P. aeruginosa pneumonia mimicking that in patients with CF, we studied whether the inflammation and antibody responses could be changed by treatment with the Chinese herbal medicine ginseng. An aqueous extract of ginseng was injected subcutaneously, and cortisone and saline were used as controls. Two weeks after challenge with P. aeruginosa, the ginseng-treated group showed a significantly improved bacterial clearance from the lungs (P < 0.04), less severe lung pathology (P = 0.05), lower lung abscess incidence (P < 0.01), and fewer mast cell numbers in the lung foci (P < 0.005). Furthermore, lower total immunoglobulin G (IgG) levels (P < 0.01) and higher IgG2a levels (P < 0.025) in serum against P. aeruginosa sonicate and a shift from an acute type to a chronic type of lung inflammation compared to those in the control and cortisone-treated groups were observed. These findings indicate that ginseng treatment of an experimental P. aeruginosa pneumonia in rats promotes a cellular response resembling a TH1-like response. On the basis of these results it is suggested that ginseng may have the potential to be a promising natural medicine, in conjunction with other forms of treatment, for CF patients with chronic P. aeruginosa lung infection.

Animals↗