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PubMedDate not supplied

[Effect of in-home boiling and refrigeration on bacterial load of pasteurized milk]

OBJECTIVES: To assess the efficacy of in-home boiling of pasteurized milk in reducing the bacterial load and the ability of the refrigeration in preserving the milk after boiling.METHODS: Thirty samples of pasteurized milk bought in São Paulo, Brazil, were submitted to in-home boiling procedure at the laboratory. Portions of samples were taken before and after boiling, and after 2, 4, 6 and 24 hours under refrigeration for microbiological analyses. Methods used were mesophilic bacteria count, and coliforms and Escherichia coli (E.coli) enumeration.RESULTS: No sample presented mesophilic bacteria count above the Brazilian standard for pasteurized milk. E.coli was not recovered from any sample. Ten samples (33%) had coliform bacteria; of these, 3 samples (10%) were above the standard. Mesophilic bacteria count after boiling was significantly lower than before boiling. After 24 hours under refrigeration, mesophilic bacteria count was significantly higher than after boiling. No significant differences were found between the intervals of 2, 4, 6 and 24 hours under refrigeration. Samples before boiling presented significantly higher coliform bacteria. No coliform bacteria were recovered at any time after boiling.CONCLUSIONS: In-home boiling of milk reduced bacterial load, while refrigeration kept bacteria under low counts.

Journal Article↗
PubMed2001

High bacterial load in asymptomatic diabetic patients with neurotrophic ulcers retards wound healing after application of Dermagraft.

Diabetic neuropathic foot ulcers are a major healthcare burden. These chronic wounds always have a bacterial load, and although normal flora is not harmful, increased tissue burden may impede healing before clinical signs of infection are evident. In this study, chronic noninfected diabetic neuropathic foot ulcers (those with adequate blood supply and pressure offloading) were assessed for bacterial burden immediately before the application of a skin substitute. Eight patients with diabetic neuropathic foot ulcers greater than 1 cm2 and free of necrotic tissue had 3-mm tissue biopsies taken from the ulcer base for quantitative bacteriology. Five of the eight patients (75%) had greater or equal to 10(5) colony forming units/gram organisms present despite the absence of clinical signs of infection. Wound healing rates were linked to bacterial load as determined from quantitative biopsy--no growth was associated with a wound healing rate of 0.2 cm per week, 10(5) to 10(6) colony forming units/gram was associated with a healing rate of 0.15 cm per week, and greater than 10(6) colony forming units/gram was associated with 0.05 cm/per week healing rate. High bacterial burden impeded healing both before and after the application of the skin substitute. The authors will change their clinical practice to assess all diabetic neuropathic foot ulcers using quantitative skin biopsies before applying skin substitutes. All patients will be treated with combination antibiotics and repeat biopsies obtained with decreased bacterial burden (< 10(6) colony forming units/gram) prior to using any bioengineered skin substitute or growth factor treatment.

Aged↗
PubMed2000

Bacterial load in tissues and its predictive value for infection in open fractures.

The role of quantitative bacteriology is considered controversial for the prediction of infection in open fractures. A study was done in 20 patients with open fractures. Post debridement pieces of skin, muscle and periosteal tissue were obtained for quantitative bacterial counts. Among a total of 50 samples from all of the tissues, 29 showed positive bacterial counts (16 of 20 skin, 11 of 20 muscle and 2 of 10 periosteum samples). By quantitative estimation, the bacterial load was >10(5) per gram in 10 skin and 3 muscle tissue samples. Infection developed in 9 of the 20 cases within one month, and eight of these patients had contamination of >10(5) per gram in 8 of the skin but only 3 muscle samples. It was concluded that with tissue specific bacterial load estimation, prediction of subsequent infection can be made if skin tissue contains >10(5) per gram, or if muscle tissue carries any level of bacterial presence.

Journal Article↗
PubMed1997

Murine CD4 T-cell response to Helicobacter infection: TH1 cells enhance gastritis and TH2 cells reduce bacterial load.

BACKGROUND & AIMS: Previous findings suggest that TH1 cellular immune responses contribute to Helicobacter-associated gastritis. To further investigate this issue, interleukin 4 gene targeted mice were infected with Helicobacter felis, and a series of adoptive transfer experiments was performed to evaluate the role of both TH1 and TH2 cells. METHODS: Antigen-specific spleen cells from immunized/challenged or nonimmunized/infected mice or CD4+ T-cell lines were transferred adoptively into naive recipients before live bacterial challenge. RESULTS: Transfer of cells from both groups of donors as well as TH1 or TH2 cell lines exacerbated gastric inflammation in the recipients. No effect on bacterial load was observed in recipients of bulk spleen cells from infected mice or recipients of TH1 cell lines. In contrast, when either a TH2 cell line or bulk cells from immunized challenged mice were transferred adoptively, recipients showed a dramatic reduction in bacterial load. Increased numbers of bacteria were also noted in interleukin 4-deficient mice. CONCLUSIONS: These data suggest a differential contribution of TH1 and TH2 cell-mediated immune responses in Helicobacter infection: one associated with the pathogenesis of disease (TH1 phenotype) and the other associated with protection from or control of infection (TH2 phenotype).

Adoptive Transfer↗
PubMed2004

Correlation of virulence, lung pathology, bacterial load and delayed type hypersensitivity responses after infection with different Mycobacterium tuberculosis genotypes in a BALB/c mouse model.

One of the most intriguing aspects of tuberculosis is that the outcome of an infection with M. tuberculosis (TB) is highly variable between individuals. The possibility of differences in virulence between M. tuberculosis strains or genotypes has only recently been studied. There is evidence of multifactorial genetic predisposition in humans that influences the susceptibility to tuberculosis. A better understanding of differences in virulence between M. tuberculosis genotypes could be important with regard to the efforts at TB control and the development of improved antituberculosis vaccines. Survival, lung pathology, bacterial load and delayed type hypersensitivity (DTH) responses of BALB/c mice after intratracheal infection with any of 19 different M. tuberculosis complex strains of 11 major genotype families were studied. The results indicate that among genetically different M. tuberculosis strains a very broad response was present with respect to virulence, pathology, bacterial load and DTH. 'Low'-responders were the H37Rv, Canetti, Beijing-1 strains, while Beijing-2,3, Africa-2 and Somalia-2 strains were 'high'-responders. A severe pathological response correlates with a high mortality and a high CFU counts in lungs, but poorly with the degree of the DTH response.

Animals↗
PubMed2005

Pulmonary damage and bacterial load in assessment of the efficacy of simulated human treatment-like amoxicillin (2,000 milligrams) therapy of experimental pneumococcal pneumonia caused by strains for which amoxicillin MICs differ.

An experimental rat pneumonia model using two amoxicillin-susceptible (MICs, < or =0.015 and 2 microg/ml) and two non-amoxicillin-susceptible (MIC, 4 microg/ml) Streptococcus pneumoniae strains was developed for testing the efficacy of amoxicillin administered to simulate human serum kinetics after treatment with amoxicillin-clavulanate (2,000 and 125 mg, respectively, twice a day, for 2.5 days). The end points for efficacy were reductions in bacterial loads in the lungs and reductions in levels of pulmonary damage. For the amoxicillin-susceptible strains (serotypes 23F and 14), a decrease greater than 4.5 log(10) CFU/pair of lungs was obtained, and the time for which the serum antibiotic concentration (SAC) was higher than the MIC (T(S)(A)(C)(>)(MIC)) was greater than 60% of the dosing interval. For non-amoxicillin-susceptible strains, the decrease in bacterial load was 1.34 to 1.75 log(10) CFU/pair of lungs, with a T(S)(A)(C)(>)(MIC) of 46.7% of the dosing interval. An in vitro study showed that serotype 9V non-amoxicillin-susceptible strains behaved as tolerant-like to concentrations similar to those in the in vivo model. The high and maintained SACs (T(S)(A)(C)(>)(MIC), >46% for all strains) significantly diminished lung injury (affected area of the lung and lung weight), compared to that in controls, by all strains, regardless of the MIC, bactericidal behavior in in vitro killing curves, or the serotype of the infecting strain. These results show the importance of host therapeutic end points in the evaluation of antibiotic efficacy. The antibiotic was more efficacious, for one nonsusceptible strain tested, when the treatment was started early (1 h postinoculation [p.i.]) than when treatment was delayed (24 h p.i.).

Amoxicillin↗
PubMed1999

Treatment of H. pylori infected mice with antioxidant astaxanthin reduces gastric inflammation, bacterial load and modulates cytokine release by splenocytes.

Helicobacter pylori is a gram-negative bacterium affecting about half of the world population, causing chronic gastritis type B dominated by activated phagocytes. In some patients the disease evolves into gastric ulcer, duodenal ulcer, gastric cancer or MALT lymphoma. The pathogenesis is in part caused by the immunological response. In mouse models and in human disease, the mucosal immune response is characterized by activated phagocytes. Mucosal T-lymphocytes are producing IFN-gamma thus increasing mucosal inflammation and mucosal damage. A low dietary intake of antioxidants such as carotenoids and vitamin C may be an important factor for acquisition of H. pylori by humans. Dietary antioxidants may also affect both acquisition of the infection and the bacterial load of H. pylori infected mice. Antioxidants, including carotenoids, have anti-inflammatory effects. The aim of the present study was to investigate whether dietary antoxidant induced modulation of H. pylori in mice affected the cytokines produced by H. pylori specific T-cells. We found that treatment of H. pylori infected mice with an algal cell extract containing the antioxidant astaxanthin reduces bacterial load and gastric inflammation. These changes are associated with a shift of the T-lymphocyte response from a predominant Th1-response dominated by IFN-gamma to a Th1/Th2-response with IFN-gamma and IL-4. To our knowledge, a switch from a Th1-response to a mixed Th1/Th2-response during an ongoing infection has not been reported previously.

Animals↗
PubMed1999

NOS2-derived nitric oxide regulates the size, quantity and quality of granuloma formation in Mycobacterium avium-infected mice without affecting bacterial loads.

Granuloma formation in response to mycobacterial infections is associated with increased expression of inducible nitric oxide synthase (NOS2) within granuloma macrophages and increased levels of nitrate/nitrite in the sera of infected mice. Continuous treatment with 5 mm or 10 mm l-N6-(1-imino-ethyl)-lysine (L-NIL), a selective NOS2-inhibitor, in acidified drinking water for up to 7 weeks consistently reduced infection-induced nitrate/nitrite to background levels in mycobacteria-infected BALB/c mice. Oral treatment with 5 mm L-NIL initiated at the time of infection significantly exacerbated growth of Mycobacterium tuberculosis, but had no effect on Mycobacterium avium colony-forming unit development in the liver, spleen and lungs of intravenously infected mice. In order to examine the role of nitric oxide in mycobacteria-induced granulomatous inflammation in the absence of any effect on the bacterial load, M. avium-infected mice were treated with 5 mm L-NIL from day 1 through 38 and the development of granulomatous lesions in the liver was assessed by histology, immunohistology and reverse-transcription-polymerase chain reaction (RT-PCR). Computer- and video-assisted morphometry performed at 4 and 7 weeks post-infection showed that treatment with L-NIL led to markedly increased number, cellularity and size of granulomatous lesions in infected mice regardless of the virulence of the M. avium isolate used for infection. Immunohistology of the liver revealed that in mice treated with L-NIL, the numbers of CD3+ T cells, CD21/35+ B cells, CD11b+ macrophages and RB6-8C5+ granulocytes associated with granulomatous lesions was increased. RT-PCR of the liver showed that in L-NIL-treated mice infected with M. avium, mRNA levels of tumour necrosis factor, interleukin-12p40, interferon-gamma, interleukin-10 and interferon-gamma-inducible protein-10 (IP-10) were up-regulated, while mRNA levels of interleukin-4, monocyte chemotactic protein-1 (MCP-1) and MCP-5 were similar to those in untreated control infected mice. When M. avium-infected mice were treated with 5 mm L-NIL between the 5th and 12th weeks of infection, similar changes in granuloma number and size were found in the absence of any effect on the bacterial load. These findings demonstrate that nitric oxide regulates the number, size and cellular composition of M. avium-induced granulomas independently of antibacterial effects by modulating the cytokine profile within infected tissues.

Analysis of Variance↗
PubMedDate not supplied

Heavy bacterial loads of H. pylori may precipitate duodenal ulcer bleeding but not bleeding severity.

BACKGROUND/AIMS: To determine whether severity of Helicobacter pylori (H. pylori) infection is aggravated during acute duodenal ulcer bleeding and related to bleeding severity. METHODOLOGY: One hundred and thirty-eight patients with H. pylori-infected bleeding duodenal ulcer and 112 non-bleeding cases were included in the study. A comparison was made of the anti-H. pylori IgG titer, endoscopic finding, density of H. pylori (range: 1-5) in the antrum, and severity of antral gastritis (score: 0-3) between bleeding and non-bleeding cases. The role of H. pylori in bleeding cases was further analyzed to survey its relationship to the severity of bleeding judged by clinical parameters. The H. pylori status of patients with rebleeding within the first week was compared to that of the non-rebleeding cases as well. RESULTS: The anti-H. pylori IgG titer and H. pylori density of the non-bleeding group were lower than those of the bleeding group (0.466+/-0.288 vs. 0.912+/-0.559, p<0.001; 2.13+/-1.02 vs. 3.34+/-1.32, p<0.001). The percentages of bleeding ulcers in the study cases increased in a trend as the density of H. pylori increased (density: 1-5; 32.7%, 33.8%, 57.4%, 81.3%, 91.4%, p<0.001). Although the severity of gastritis and density of H. pylori disclosed an upward trend as bleeding severity increased, only ulcer size was significantly associated with bleeding severity (p<0.05). The 10 cases with recurrent bleeding had higher bacterial density and serological titer than the 128 non-rebleeding cases (p<0.005). CONCLUSIONS: Heavy bacterial loads of H. pylori infection may precipitate bleeding episodes of duodenal ulcer. However, in bleeding duodenal ulcer, the status of H. pylori infection is not strongly associated with initial bleeding severity before therapeutic endoscopy. With the aim of enhancing hemostasis and preventing rebleeding, further studies could focus on diminishing the bacterial load of H. pylori during bleeding episodes.

Adult↗
PubMed2006

Pilot study to evaluate 3 hygiene protocols on the reduction of bacterial load on the hands of veterinary staff performing routine equine physical examinations.

Reduction factors (RFs) for bacterial counts on examiners' hands were compared when performing a standardized equine physical examination, followed by the use of one of 3 hand-hygiene protocols (washing with soap, ethanol gel application, and chlorohexidine-ethanol application). The mean RFs were 1.29 log10 and 1.44 log10 at 2 study sites for the alcohol-gel (62% ethyl alcohol active ingredient) protocols and 1.47 log10 and 1.94 log10 at 2 study sites for the chlorhexidine-alcohol (61% ethyl alcohol plus 1% chlorhexidine active ingredients) protocols, respectively. The RFs were significantly different (P < 0.0001) between the hand-washing group and the other 2 treatment groups (the alcohol-gel and the chlorhexidine-alcohol lotion). The use of alcohol-based gels or chlorhexidine-alcohol hand hygiene protocols must still be proven effective in equine practice settings, but in this study, these protocols were equivalent or superior to hand washing for reduction in bacterial load on the hands of people after they perform routine physical examinations.

Animals↗
PubMed1998

Bacterial load and protein deposits on 15-day versus 1-day disposable hydrophilic contact lenses.

PURPOSE: This study quantified the bacterial load and protein deposits on 1- and 15-day disposable contact lenses after use in normal wearers. METHODS: Sixteen patients were randomly assigned to a 1-day contact lens (1-Day Acuvue) in one eye and to a 15-day contact lens (Acuvue) in the contralateral eye. Only one specified solution was allowed for the care of 15-day lenses. All patients were evaluated every month for 6 months (at times T1, T2, T3, T4, T5, T6). At times T1, T3, and T5, the lenses were removed in a sterile fashion and sent for laboratory quantification of Staphylococcus aureus and Pseudomonas aeruginosa. At T2, T4, and T6, quantification of protein deposits was determined, and at T0 and T6, impression cytology of the conjunctiva was performed. RESULTS: P. aeruginosa was not identified on any lens. At T1, T3, and T5, S. aureus was significantly greater on the 1-day versus 15-day lenses (p < 0.001). In contrast, protein deposits were significantly greater on the 15-day lenses at all time points (T2, T6: p < 0.01; T4: p < 0.05). Impression cytology of the 15-day lens eyes revealed a worsening trend compared to the 1-day lens; however, no statistically significant differences were found between the two groups (p = 0.29). CONCLUSION: Results of this study suggest that the use of cleaning and preservative solutions can alter the ocular surface bacterial environment of the contact lens wearer and that these changes are not a direct consequence of contact lens wear. The bactericidal activity of these solutions could, with time, also affect ocular surface cells, leading to contact lens intolerance and ocular surface disease.

Adult↗
PubMed2006

Effect of vaginal douching and different semen extenders on bacterial load and fertility in turkeys.

1. A study on artificial insemination of Beltsville Small White turkeys investigated the effect on bacterial load and fertility of vaginal douching with diluents containing Gentamicin 400 microg/ml and different semen extenders. 2. Irrespective of the extenders used, vaginal douching with Gentamicin reduced the microbial load of the vagina with resultant improvement in fertility and hatchability and corresponding reduction in embryonic mortality. 3. Eggs from hens inseminated with semen extended with Beltsville Poultry Semen Extender (BPSE) diluent along with vaginal douching showed a trend towards higher per cent fertility and per cent hatchability of total and fertile eggs set compared to other extenders, though this was non-significant.

Animals↗
PubMed1975

Reduction of skin bacterial load with use of the therapeutic whirlpool.

Effects of immersion time, water temperature, and three whirlpool treatment techniques on the reduction of bacterial load on the plantar surface of feet were examined. When cultures were taken before and after treatment, water temperature was found not to be a significant factor when removal of bacteria is the primary objective in a vascularly uncompromised limb. Maximum reduction of bacterial count in water at 37.7 degrees Celsius appeared to be obtained after immersion about twenty minutes. Although agitation of the water was significantly better than either spraying or soaking the foot, agitation followed by spraying was significantly better than any single technique in removing bacteria.

Baths↗
PubMedDate not supplied

A semi quantitative analysis of bacterial load in different cell types in leprous nerves using transmission electron microscope.

Thirty lepromatous (BL-LL) and 25 tuberculoid (TT-BT) nerve lesions obtained from untreated cases of leprosy were scanned using transmission electron microscope for assessing the bacterial load in different cell types. Major bulk of infection was seen in the Schwann cells of nonmyelinated fibres, in both early lepromatous and tuberculoid nerve lesions, suggesting that M. leprae spread mainly via the Schwann cells within the nerve.

Colony Count, Microbial↗
PubMedDate not supplied

Immunological status of ENL (erythema nodosum leprosum) patients: its relationship to bacterial load and levels of circulating IL-2R.

Recent data suggest that the clinical course of reactional states in leprosy is closely related to the cytokine profile released locally or systemically by the patients. In the present study, patients with erythema nodosum leprosum (ENL) were grouped according to the intensity of their clinical symptoms. Clinical and immunological aspects of ENL and the impact of these parameters on bacterial load were assessed in conjunction with patients' in vitro immune response to mycobacterial antigens. In 10 out of the 17 patients tested, BI (bacterial index) was reduced by at least 1 log from leprosy diagnosis to the onset of their first reactional episode (ENL), as compared to an expected 0.3 log reduction in the unreactional group for the same MDT (multidrug therapy) period. However, no difference in the rate of BI reduction was noted at the end of MDT among ENL and unreactional lepromatous patients. Accordingly, although TNF-alpha (tumor necrosis factor) levels were enhanced in the sera of 70.6% of the ENL patients tested, no relationship was noted between circulating TNF-alpha levels and the decrease in BI detected at the onset of the reactional episode. Evaluation of bacterial viability of M. leprae isolated from the reactional lesions showed no growth in the mouse footpads. Only 20% of the patients demonstrated specific immune response to M. leprae during ENL. Moreover, high levels of soluble IL-2R (interleukin-2 receptor) were present in 78% of the patients. Circulating anti-neural (anti-ceramide and anti-galactocerebroside antibodies) and anti-mycobacterial antibodies were detected in ENL patients' sera as well, which were not related to the clinical course of disease. Our data suggest that bacterial killing is enhanced during reactions. Emergence of specific immune response to M. leprae and the effective role of TNF-alpha in mediating fragmentation of bacteria still need to be clarified.

Adolescent↗
PubMed1999

Reduction of the bacterial load by the silver-coated endotracheal tube (SCET), a laboratory investigation.

Microaspiration enabled by high-volume-low-pressure cuffed endotracheal tubes is the most likely explanation for ventilator-associated pneumonia. To decontaminate the secretion at the proximal end of the cuff we developed a silver-coated endotracheal tube (SCET). In an in vitro model we investigated the efficacy of SCET to lower the bacterial load of secretion and aspirate. We developed a continuously contaminated and mechanically ventilated oropharynx-larynx-lung model to investigate the reduction of the bacterial count by SCET compared to controls. The model was continuously contaminated via the oropharynx-larynx with Pseudomonas aeruginosa ATCC 27853. During the investigation period of 50 hours the bacterial count of oropharynx-larynx and lung was measured as colony-forming-units/ml. In addition, the characteristic curve of silver ion release of SCET was determined. SCET significantly reduced the bacterial count in oropharynx-larynx at all timepoints (p < 0.05). In lung the bacterial count was significantly lower beginning with the 36th hour of recording (p < 0.05). A reduction of greater than 2 log was found from 28 hours on in oropharynx-larynx and from 50 hours on in lung. The release of silver ions was very rapid and was described by a mono-exponential function with a time-constant tau of about 60 minutes and a saturation concentration of 200 +/- 80 microg/l. SCET showed a significant inhibition of growth of P. aeruginosa in the continuously contaminated and mechanically ventilated oropharynx-larynx-lung model. SCET by thus might be helpful in reducing ventilator-associated pneumonia.

Bacterial Infections↗
PubMed1995

Intestinal B-cell isotype response in relation to local bacterial load: evidence for immunoglobulin A subclass adaptation.

BACKGROUND & AIMS: In experimental animals, the indigenous microbiota modulates mucosal immunity. In humans, such direct evidence is scarce. The aim of this study was to examine the effect of intestinal bacteria on the local immunoglobulin (Ig) response. METHODS: The numbers of IgA-, IgM-, and IgG-producing immunocytes per defined mucosal length unit were determined, and the local IgA subclass response was studied using immunohistochemistry in jejunal segments from adults with bacterial overgrowth and in sterile ileal urinary conduits from children. RESULTS: The ileal bladder mucosa showed atrophy, but the number of immunocytes only tended to be decreased. The jejunal segments with bacterial overgrowth showed minor histological changes; the numbers of IgA and IgG immunocytes were fairly normal, whereas the number of IgM immunocytes was significantly reduced (P < 0.05) (12 cells/U) compared with control mucosa (24 cells/U). The number of IgA2 immunocytes was significantly decreased (P < 0.01) in ileal conduits (7 cells/U or 30% of total IgA) but increased (P < 0.05) in jejunal segments with bacterial overgrowth (42 cells/U or 43% of total IgA) compared with normal ileum (15 cells/U or 40% of total IgA) and jejunum (24 cells/U or 23% of total IgA). CONCLUSIONS: An association exists between bacterial load and IgA subclass production. An increase in IgA2 may enhance mucosal protection and probably reflects immunomodulation caused by lipopolysaccharides.

Adolescent↗