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PubMed1978

Disk agar diffusion susceptibility testing of yeasts.

A disk agar diffusion method was developed for testing the susceptibility of rapidly growing yeasts in vitro. A totally defined, completely synthetic agar culture medium (synthetic amino acid medium, fungal) and clinical isolates of Candida spp. and Torulopsis glabrata were used. Turbidimetric adjustment of cell suspensions resulted in standard, reproducible inocula, which gave sharp, clear zones of inhibition when applied by an agar overlay method. Optimal disk loads were determined for amphotericin B, amphotericin B methyl ester, 5-fluorocytosine, clotrimazole, and miconazole. Disk potencies were stable over a 2-month period when stored in a vacuum desiccator at -30 degrees C. Using an error ratebounded classification, the zones of inhibition were correlated with both broth dilution and agar dilution minimum inhibitory concentrations (MICs). With amphotericin B and amphotericin B methyl ester, all isolates were susceptible, yielding zone diameters which clustered within 5 mm. Overall correlations between zone diameters and broth dilution MICs with 5-fluorocytosine, miconazole, and clotrimazole were 97, 96, and 82% (excluding T. glabrata), respectively; correlations of zone diameters with agar dilution MICs were 96, 92, and 88%, respectively. Disk diffusion susceptibility testing of yeasts appears to be generally applicable. However, when results are equivocal, quantitative test methods should be used.

Amphotericin B↗

PubMed1998

Sanitation characteristics of some food processing industries.

The present investigation was carried out to evaluate the sanitary conditions surrounding the food throughout the production stages in some food plants. Observation of the sanitary measures of the studied plants revealed that only 3 out of the 7 plants (42.9%) have acceptable sanitation that complies with the sanitary requirements specified by WHO. Personal hygiene and storage conditions were the most critical problems found in the studied plants. Laboratory examination of nasal and throat swabs and stool samples of workers was carried out to uncover the chronic carriers. Among the food handlers examined 46.3% were positive for intestinal parasites. Bacteriological examination of stool specimens revealed that 4.3% of carriers of Salmonella paratyphi and none were carriers of Vibreo species. Nasal swabs were also positive for Staph. aureus in 29.8% of all the examined swabs. Analysis of the main products of the studied plants revealed generally that the bacterial load of the products of plants having acceptable sanitary conditions was lower than that of the products of the other plants. The frozen vegetable products had a total aerobic mesophilic plate count ranging from 8.1 x 10(4) cfu/g in okra and 3.7 x 10(5) cfu/g in mixed vegetables. The total aerobic plate count of the ice cream (1 x 10(3) cfu/g) complies with specified Egyptian standards. However, the coliform count (9 x 10(1) MPN) was higher than the recommended limit. Lead and cadmium levels were also investigated in all products. The maximum detected level of lead was that of cream wafer (0.94 ppm) followed by banana wafer (0.82 ppm). The two detected levels were higher than Egyptian standards. The lead level in ice cream (0.19 ppm) was also higher than the specified standards. The relatively high levels of lead in cream wafer and ice cream may be attributed to more than one factor; the added color and the old machinery used in some production steps are the most accursed factors. On the other hand, the observed level of cadmium ranged between 0.046 ppm in raw mil and 0.3 ppm in soft cheese.

Colony Count, Microbial↗

PubMed2005

Water quality assessment and modeling of an effluent-dominated stream, the Notwane River, Botswana.

In an effort to assess current and future water quality of the only perennial river in southeastern Botswana, this study presents water quality monitoring and modeling results for the effluent-dependent Notwane River. The water quality along the Notwane River, pre- and post-implementation of secondary wastewater treatment, was compared and results demonstrated that water quality improved after the new wastewater treatment plant (WWTP) went online. However, stream standards for chemical oxygen demand, total dissolved phosphorous, and fecal coliform were exceeded in most locations and the critical dissolved oxygen (DO) reached concentrations of less than 4 mg L(-1). High dissolved P concentrations and intense macrophyte growth at the impounding ponds and at sites within 30 km of the effluent waste stream confluence suggest that eutrophication was a function of P release from the ponds. Results of DO modeling demonstrated that an unpolluted inflow at approximately 10 km downstream of the confluence was responsible for raising DO concentrations by 2.3 mg L(-1), while SOD was responsible for a decline in DO concentrations of 1.4 mg L(-1) at 6 km downstream of the confluence. Simulations also showed higher DO concentrations during winter months, when water temperatures were lower. Simulations, in which the distributed biochemical oxygen demand (BOD) loading from cattle excrement was decreased, produced nominal increases in DO concentrations. An increase in WWTP BOD loadings to projected 2020 values resulted in a 1.3 mg L(-1) decrease in the critical DO concentration. Furthermore, a decrease in treatment plant efficiency, from 94% to 70% BOD removal, produced critical DO concentrations and anoxia along much of the modeled reach. This has significant implications for Gaborone, especially if decreased WWTP efficiency occurs as a result of the expected future increase in pollutant loadings.

Ammonia↗

PubMed1996

Microbiological analysis of 'black pudding', a Trinidadian delicacy and health risk to consumers.

The prevalences of Salmonella, Escherichia coli and Staphylococcus aureus in black pudding which originated from local vendors and supermarkets in Trinidad were determined. The enterotoxigenicity of S. aureus strains and occurrence of O157:H7 strains amongst E. coli isolates were also investigated. For the 100 black puddings each sampled from supermarkets and vendors, the mean total aerobic plate count (TAPC) per g was 1.8 x 10(7) +/- 1.5 x 10(7) and 1.5 x 10(8) +/- 2.3 x 10(8), respectively. E. coli was isolated from 56 (56.0%) black pudding samples from supermarkets with a mean count per g of 9.2 x 10(6) +/- 7.9 x 10(6) compared to a prevalence of 79% (79 of 100) and mean count per g of 3.2 x 10(7) +/- 4.7 x 10(7) for samples from local vendors. The difference between prevalences was statistically significant (P < or = 0.001; chi 2). Only 1 (2.2%) of 45 strains of E. coli from supermarket-purchased pudding tested, was an 0157:H7 strain compared to 9 (13.6%) of 66 strains of E. coli from vendor-sold black pudding. The difference was not statistically significant (P > or = 0.05; chi 2). Five (5.0%) of 100 black pudding samples from supermarkets yielded Salmonella, with S. ohio being the predominant serotype. For vendor-sold black pudding however, 11 (11.0%) samples were positive for Salmonella with a new serotype, S. unnamed (4,12:d-) being responsible for 50% (6 of 12) of isolates from this source. Forty samples each of black pudding from supermarkets and vendors were all (100.0%) positive for S. aureus with mean counts per g being 3.1 x 10(5) +/- 8.8 x 10(5) and 3.3 x 10(6) +/- 7.7 x 10(6), respectively. Overall, 27 (33.8%) of 80 strains of S. aureus tested were enterotoxigenic producing staphylococcal enterotoxins A(SEA), SEB, SEC, SED or a combination. It was concluded that black pudding poses a high risk to consumers based on the prevalence, microbial load and toxigenicity of the pathogens detected.

Culture Media↗

PubMed2006

[Guideline for the treatment of Hansen's disease in Japan (Second edition)].

ad hoc committee of Japanese Leprosy Association recommends revised standard treatment protocol of leprosy in Japan, which is a modification of World Health Organization's multidrug therapy (WHO/MDT, 1997). For paucibacillary (PB) leprosy, 6 months treatment by rifampicin and dapsone (MDT/PB) is enough. However, for high bacterial load multibacillary (MB) leprosy, 12 months treatment seems insufficient. Thus, (A) For MB with bacterial index (BI) > or = 3 before treatment, 2 years treatment by rifampicin, dapsone and clofazimine (MDT/MB) is necessary. When BI become negative and active lesion is lost within 2 years, no maintenance therapy is necessary. When BI is still positive, one year of MDT/MB is added (3 years in total), followed by maintenance therapy by dapsone and clofazimine until BI negativity and loss of active lesions. (B) For MB with BI < 3 or fresh MB (less than 6 months after the onset of the disease) with BI > or = 3, 1 year treatment by MDT/MB is necessary. When BI become negative and active lesion is lost within one year, no maintenance therapy is necessary. When BI is still positive or active lesion is remaining, additional therapy with MDT/MB for one more year is recommended. This is a simplification of first version in 2000. Brief summary of diagnosis, purpose of therapy, character of drugs, and prevention of deformity is also described.

Clofazimine↗

PubMed1977

Intrasplenic autotransplantation of canine pancreatic tissues. Maintenance of normoglycaemia after total pancreatectomy.

In mongrel dogs, the horizontal part of the pancreas was infiltrated with collagenase, cut in pieces, incubated with collagenase, rinsed twice by centrifugation or sedimentation, and implanted into the spleen of the same animal. The operations were terminated by the removal of the rest of the pancreas. Of 26 operated dogs, one died because of a duodenal perforation, five developed severe hyperglycaemia without remission, and 20 were long-term normoglycaemic survivors followed for up to 10 weeks. These 20 animals became spontaneously normoglycaemic in the course of the first 10 postoperative days. Later, during glucose loading tests, the pattern of blood sugar values was the same in the transplanted animals as in those of a group of non-operated dogs, but the insulin release, although immediate, attained half the control values. The plasma insulin in the splenic vein was more than seven times higher than in the peripheral circulation. Splenectomies performed in seven animals were followed by severe hyperglycaemia and death. Light and electron microscopy demonstrated the presence of the intact endocrine and exocrine pancreatic tissues in the spleens of all animals investigated. It is concluded that laborious separations of endocrine from exocrine tissue are not mandatory for ulterior endocrine function, and that in an animal larger than rodents it is possible to obtain a diabetes-preventing function after the transplantation of only a part of the gland.

Animals↗

PubMed2003

Low-cost antibiotic loaded systems for developing countries.

Treatment of osteomyelitis with local antibiotic delivery systems has become a common practice in orthopaedic surgery. This study attempted to show that locally produced pure or bioglass reinforced plaster of Paris, hydroxyapatite and sodium alginate are promising biomaterials and mainly because of economical reasons and availability, may be an alternative in clinical practice, especially for developing countries. A total of 32 rabbits were divided into four groups (n:8). In group A, sodium alginate + cephazoline; in group B, plaster of Paris + bioglass + cephazoline; in group C, plaster of Paris + hydroxyapatite + cephazoline and in group D, plaster of Paris + cephazoline were used. The blood serum cephazoline concentrations were analyzed by high performance liquid chromatography on days 1 to 10 everyday and then at days 13, 17, 18, 24, 25 and 30. The mean values +/- standard deviations and median values of blood serum antibiotic concentrations for groups A, B, C and D were 1.45 +/- 0.40 (1.42) mcg/ml, 1.53 +/- 0.64 (1.31) mcg/ml, 1.92 +/- 0.39 mcg/ml (1.90) and 1.41 +/- 0.65 (1.25) mcg/ml, respectively. The detected antibiotic level was constantly over the minimum inhibitory concentration for Staphylococcus aureus. In conclusion, it can be stated that these materials are promising as a antibiotic delivery system even with simple production methods.

Alginates↗

PubMed2007

Performance and microbial analysis of defined and non-defined inocula for the removal of dimethyl sulfide in a biotrickling filter.

The performance and microbial communities of three differently inoculated biotrickling filters removing dimethyl sulfide (DMS) were compared. The biotrickling filters were inoculated with Thiobacillus thioparus TK-m (THIO), sludge (HANDS) and sludge + T. thioparus TK-m + Hyphomicrobium VS (HANDS++), respectively. The criteria investigated were length of the start-up period, the maximum elimination capacity, and the effects of intermittent loading rates, low pH, peak loading and very low loading rate on the DMS removal efficiency. The HANDS++ reactor exhibited the best performance considering all treatments. HANDS performed almost equally well as HANDS++, except during the determination of the EC(max), while THIO was generally the least efficient. During stable DMS loading at concentrations of 20 ppmv or lower, all reactors exhibited similar and high removal efficiencies (>99%). Denaturing gradient gel electrophoresis (DGGE) analysis showed the establishment of T. thioparus in the biofilm of all reactors, but not of Hyphomicrobium VS. Quantitative monitoring of the introduced bacterial strains was performed with a newly developed real-time PCR protocol. Initially, the inoculated strains were exclusively found in the reactors in which they were added. Afterwards, however, both strains developed in the biofilm of all three reactors, although T. thioparus attained higher cell densities than Hyphomicrobium. The presence of T. thioparus in THIO was related with the DMS loading rates that were applied, in the sense that intermittent DMS loading and very low DMS loading rates (0.5 ppmv) induced a decrease in gene copy numbers. Real-time PCR and DGGE both gave consistent results regarding the presence of Hyphomicrobium VS and Thiobacillus thioparus TK-m in the reactors. Only real-time PCR could be used to detect bacteria comprising of less than 1.4% of the total bacterial community ( approximately 10(5) copies ring(-1)).

Air Pollutants↗

PubMed2006

Treatment of head and neck dermatitis with ciclopiroxolamine cream--results of a double-blind, placebo-controlled study.

In atopic dermatitis, microbial allergens may be pathogenetically significant. Apart from Staphylococcus aureus, these are primarily lipophilic Malassezia yeasts. They are particularly involved in the pathogenesis of head and neck dermatitis (HND), a special form of atopic dermatitis, which is often difficult to treat. Fifty patients (21 men, 29 women) with moderate to severe HND of at least 6 months' duration were included in a prospective double-blind study. All of them showed at least 10% involvement of the head-neck region. The severity of disease was evaluated by Investigator Global Assessment (IGA), Eczema Area and Severity Index (EASI) for the head-neck region and a pruritus score. IgE antibodies to Malassezia sympodialis and/or Malassezia furfur (at least CAP class 1) were a prerequisite for study enrollment. Either 1% ciclopiroxolamine cream (Batrafen; Aventis Pharma, Bad Soden, Germany) or the corresponding base cream were thinly applied to the affected areas twice daily for 28 days. Sixteen patients in the ciclopiroxolamine group and 13 patients in the placebo group completed the study. To assess the change in severity of atopic eczema, IGA differences between the individual measuring points were determined for all patients. There were significant differences in the IGA score change between the ciclopiroxolamine group and the placebo group, from t3 to t4, and over the total period. Similar, but not significant, changes were observed with the EASI score, in terms of affected skin area and itching. The present study is the first to examine the effect of antifungal single-drug therapy with a cream containing ciclopiroxolamine on the course of HND. The study medication was found to be significantly effective. To optimize this effect, suitable patients selected in terms of fungal load, specific IgE, prick test and particularly atopy patch test for Malassezia antigens could receive combined treatment with antimycotic-containing shampoos and/or short-term systemic antimycotic therapy in severe cases.

Adolescent↗

PubMed2000

Importance of protease inhibitor plasma levels in HIV-infected patients treated with genotypic-guided therapy: pharmacological data from the Viradapt Study.

OBJECTIVE: In a prospective randomized study, the impact of plasma protease inhibitor (PI) trough levels on changes in HIV RNA were assessed in patients treated with genotypic-guided therapy. METHODS: Patients failing combination therapy (HIV-1 RNA > 10,000 copies/ml, and at least 6 months of therapy with nucleoside analogues and 3 months with PI) were randomly assigned into two arms: control group (C) in which the treatment was modified according to the standard of care; genotypic group (G) in which the treatment was modified according to resistance mutation profiles. Serial PI plasma levels were performed in patients throughout the 12 month study. PI levels were determined by high performance liquid chromatography. 'Suboptimal' concentration (SOC) was defined as at least two PI plasma levels below 2 x IC95. Others were defined as 'optimal' concentration (OC). Patients were categorized into four groups: G1 (SOC/control); G2 (OC/control); G3 (SOC/genotype); G4 (OC/genotype). An intent-to-treat analysis was performed with viral load as the primary endpoint. RESULTS: A total of 81 patients [mean age 39.7 +/- 8 years, 59 men, 52.7% Centers for Disease Control and Prevention (CDC) stage C] were included in the pharmacological substudy. The two groups according to randomization arms were comparable in terms of risk factor, age, sex, previous treatments, baseline CD4 cell count, HIV-1 RNA and mean PI plasma concentrations. Linear regression analysis showed a significant relationship between PI concentration and HIV RNA in the plasma. OC and SOC were found in 67.9% (55/81) and 32.1% (26/81) of patients, respectively. Mean changes in HIV RNA from baseline at month 6 were: -0.23 +/- 0.29 log10 copies/ml (G1); -0.97 +/- 0.28 (G2); -0.68 +/- 0.37 (G3); -1.38 +/- 0.20 (G4). Multivariate analysis showed PI plasma concentrations to be an independent predictor of HIV-RNA evolution (P = 0.017). CONCLUSION: Multiple parameters determine the response to antiretroviral therapy and causes other than the development of drug resistance should be considered in the setting of therapeutic failure. Suboptimal concentrations of PI limit the response to antiretroviral therapy. Therapeutic drug monitoring of the PI plasma concentration may therefore prove useful in optimizing antiretroviral therapy.

Adult↗

PubMed1990

Microbial aggregates in anaerobic wastewater treatment.

The phenomenon aggregation of anaerobic bacteria gives an opportunity to speed up the digestion rate during methanogenesis. The aggregates are mainly composed of methanogenic bacteria which convert acetate and H2/CO2 into methane. Other bacteria are also included in the aggregates but their concentration is rather small. The aggregates may also be formed during acetogenesis or even hydrolysis but such aggregates are not stable and disrupt quickly when not fed. A two stage process seems to be suitable when high concentrated solid waste must be treated. Special conditions are necessary to promote aggregate formation from methanogenic bacteria but aggregates once formed are stable without feeding even for a few years. The structure, texture and activity of bacterial aggregates depend on several parameters: (1)--temperature and pH, (2)--wastewater composition and (3)--hydrodynamic conditions within the reactor. The common influence of all these parameters is still rather unknown but some recommendations may be given. Temperature and pH should be maintained in the range which is optimal for methanogenic bacteria e.g. a temperature between 32 and 50 degrees C and a value pH between 6.5 and 7.5. Wastewaters should contain soluble wastes and the specific loading rate should be around one kgCOD(kgVSS)-1 d-1. The concentration of the elements influences aggregate composition and probably structure and texture. At high calcium concentration a change in the colour of the granules has been observed. Research is necessary to investigate the influence of other elements and organic toxicants on maintenance of the aggregates. Hydrodynamic conditions seem to influence the stability of the granules over long time periods. At low liquid stream rates, aggregates may starve and lysis within the aggregates is possible which results in hollowing of aggregates and their floating. At high liquid stream rates the aggregates may be disrupted and washed out of the reactor as a flocculent sludge. Methanogenic bacterial aggregates have been successfully applied in many full scale installations, especially for sugar beet, potato, pulp and paper mill, and other soluble wastes. The UASB reactors used for these treatments are simple in construction and handling which result in rather low total costs. A further and wider application of UASB reactors and methanogenic aggregates for various industrial wastewaters is expected.

Bacteria, Anaerobic↗

PubMed2004

The relationship between disease pattern and disease burden by chest radiography, M. tuberculosis Load, and HIV status in patients with pulmonary tuberculosis in Addis Ababa.

BACKGROUND: We evaluated the impact of HIV coinfection on the chest radiographic pattern and extent of disease and its relation to the load of Mycobacterium tuberculosis in Ethiopian out-patients with pulmonary tuberculosis. PATIENTS AND METHODS: A total of 168 patients with cultureverified pulmonary tuberculosis had their chest X-rays (CXR) reviewed for the site, pattern, and extent of disease and the findings were correlated to (a) the mycobacterial culture count and bacillus load after sputum concentration and (b) the HIV status of the patients. RESULTS: HIV-positive patients were less likely to have cavitary disease (p < 0.001) and more likely to have pleural effusion (p = 0.08), miliary (p < 0.05), and interstitial (p < 0.01) patterns. A total of 15 (9.2%) patients had normal chest X-rays. HIV-infected patients had a CXR classified as normal or with minimal involvement (p = 0.059) and a reduced mycobacterial colony count (p = 0.002) compared to HIV-negative patients. Middle and lower lung involvement were more common in HIV-positive patients. CONCLUSION: CXR findings in the setting of an underlying HIV infection tend to be more atypical and could present as either normal or with minimal involvement. In general, HIV-positive patients had lower colony count of M. tuberculosis than HIV-negative patients. Of particular interest is the finding of a large number of normal chest X-rays in HIV-infected patients. With the rising incidence of both tuberculosis and HIV infection in Ethiopia, the finding of a normal chest X-ray and a negative smear poses a challenge for the diagnosis of pulmonary tuberculosis.

Adolescent↗

PubMed2003

Controlled clinical trials evaluating the homeopathic treatment of people with human immunodeficiency virus or acquired immune deficiency syndrome.

CONTEXT: Homeopathic medicine developed significant popularity in the nineteenth century in the United States and Europe as a result of its successes treating the infectious disease epidemics during that era. Homeopathic medicine is a medical system that is specifically oriented to using nanopharmacologic and ultramolecular doses of medicines to strengthen a person's immune and defense system rather than directly attacking the microbial agents. OBJECTIVES: To review the literature referenced in MEDLINE and in nonindexed homeopathic journals for placebo-controlled clinical trials using homeopathic medicines to treat people with AIDS or who are human immunodeficiency virus (HIV)-positive and to consider a different theoretical and methodological approach to treating people with the viral infection. FINDINGS: A total of five controlled clinical trials were identified. A double-blinded, placebo-controlled study was conducted on 50 asymptomatic HIV-positive subjects (stage II) and 50 subjects with persistent generalized lymphadenopathy (stage III) in whom individualized single-remedy homeopathic treatment was provided. A separate body of preliminary research was conducted using homeopathic doses of growth factors. Two randomized double-blinded, placebo-controlled studies were conducted with a total of 77 people with AIDS who used only natural therapies over a 8-16-week period. Two other studies were conducted over a 2.5-year period with 27 subjects in an open-label format. SETTINGS: The first study was conducted by the Regional Research Institute for Homeopathy in Mumbai, India, under the Central Council for Research in Homeopathy, with the approval of the Ministry of Health and Family Welfare, Government of India. The second body of studies was conducted in clinic settings in California, Oregon, Arizona, Hawaii, New York, and Washington. RESULTS: The first study found no statistically significant improvement in CD4 T-lymphocytes, but did find statistically significant pretest and post-test results in subjects with stage III AIDS, in CD4 (p = 0.008) and in CD8 (p = 0.04) counts. The second group of studies found specific physical, immunologic, neurologic, metabolic, and quality-of-life benefits, including improvements in lymphocyte counts and functions and reductions in HIV viral loads. CONCLUSIONS: As a result of the growing number of people with drug-resistant HIV infection taking structured treatment interruptions, homeopathic medicine may play a useful role as an adjunctive and/or alternative therapy.

Acquired Immunodeficiency Syndrome↗

PubMed2001

Lamivudine-zidovudine combination for prevention of maternal-infant transmission of HIV-1.

CONTEXT: Zidovudine reduces maternal-infant transmission of human immunodeficiency virus 1 (HIV-1) infection by two thirds. Combination antiretroviral therapies are potentially more effective prevention. OBJECTIVES: To assess the safety of perinatal lamivudine-zidovudine therapy, especially in children, and its effects on viral load, acquisition of drug resistance, and maternal-infant transmission of HIV-1 in a nonbreastfeeding population. DESIGN AND SETTING: The Agence Nationale de Recherches sur le SIDA (ANRS) 075 Study, an open-label, nonrandomized intervention trial conducted in the context of an ongoing observational cohort study in 48 sites in France. PATIENTS: A total of 445 HIV-1-infected pregnant women were enrolled as the study cohort from February 1997 to September 1998; controls consisted of 899 pregnant women who had received zidovudine monotherapy in May 1994 to February 1997 as standard care. INTERVENTION: The study cohort received lamivudine in addition to the standard Pediatric AIDS Clinical Trial Group 076 Study zidovudine prophylaxis regimen. Lamivudine was initiated in women at 32 weeks' gestation through delivery at 150 mg twice per day orally; children received lamivudine, 2 mg/kg twice per day for 6 weeks. MAIN OUTCOME MEASURES: HIV-1 infection status and tolerance of therapy in children through age 18 months; maternal plasma HIV-1 RNA levels through 6 weeks after delivery. RESULTS: The transmission rate in the study group was 1.6% (7/437; 95% confidence interval [CI], 0.7%-3.3%). In a multivariable analysis, transmission in the study group was 5-fold lower than in controls. In the study group, maternal plasma HIV-1 RNA level was less than 500 copies/mL at delivery in 74%; the median decrease was 1.24 (range, -1.63 to 3.40) log(10) copies/mL. The M184V lamivudine resistance mutation was detected at 6 weeks after delivery in specimens from 52 of 132 women. The most frequent serious adverse events in children were neutropenia and anemia, requiring blood transfusion in 9 children and premature treatment discontinuation in 19. Two uninfected children died at age 1 year from neurologic complications related to mitochondrial dysfunction. CONCLUSIONS: Lamivudine-zidovudine may be effective in preventing maternal-infant HIV transmission. However, severe adverse effects and emergence of resistance to lamivudine occurred. Thus, the role of this combination therapy in this setting is as yet unclear, and further research involving a variety of strategies is needed to definitively ascertain its utility for preventing maternal-infant HIV transmission.

Anti-HIV Agents↗

PubMed2006

Efficacy and potential for resistance selection of antipseudomonal treatments in a mouse model of lung infection by hypermutable Pseudomonas aeruginosa.

Hypermutable Pseudomonas aeruginosa strains are found with high frequency in the lungs of patients with chronic infections and are associated with high antibiotic resistance rates. The in vivo consequences of hypermutation for treatment in a mouse model of lung infection using strain PAO1 and its hypermutable derivative PAOdeltamutS are investigated. Groups of 30 mice were treated for 3 days with humanized regimens of ciprofloxacin (CIP), tobramycin (TOB), CIP plus TOB, or placebo, and mortality, total lung bacterial load, and 4x- and 16x-MIC mutants were recorded. The rates of mutation and the initial in vivo frequencies of mutants (at the onset of treatment) were also estimated and the in vitro- and in vivo-selected mutants characterized. Since both strains had identical MICs, the same pharmacokinetic/pharmacodynamic (PK/PD) parameters were obtained: area under the 24-h concentration-time curve (fAUC)/MIC = 385 for CIP and maximum concentration of drug in serum (fC(max))/MIC = 19 for TOB. Despite adequate PK/PD parameters, persistence of high bacterial numbers and amplification (50,000-fold) of resistant mutants (MexCD-OprJ hyperexpression) were documented with CIP treatment for PAOdeltamutS, in contrast to complete resistance suppression for PAO1 (P < 0.01), showing that conventional PK/PD parameters may not be applicable to infections by hypermutable strains. On the other hand, the efficacy of TOB monotherapy in terms of mortality reduction and bacterial load was very low regardless of the strain but not due to resistance development, since mutants were not selected for PAO1 and were only modestly amplified for PAOdeltamutS. Finally, the CIP-plus-TOB combination was synergistic, further reducing mortality and bacterial load and completely preventing resistance even for PAOdeltamutS (P < 0.01 compared to monotherapy), showing that it is possible to suppress resistance selection in infections by hypermutable P. aeruginosa using appropriate combined regimens.

Animals↗

PubMed2005

Effect of pulsed ultrasound in combination with gentamicin on bacterial viability in biofilms on bone cements in vivo.

AIMS: The aim of this study is to investigate whether pulsed ultrasound (US) in combination with gentamicin yields a decreased viability of bacteria in biofilms on bone cements in vivo. METHODS AND RESULTS: Bacterial survival on bone cement in the presence and absence of ultrasound was compared in a rabbit model. Two bone cement samples with an Escherichia coli ATCC 10798 biofilm were implanted in a total of nine rabbits. In two groups bone cement discs loaded with gentamicin, freshly prepared and aged were used, and in one group unloaded bone cement discs in combination with systemically administered gentamicin. Pulsed ultrasound with a frequency of 28.48 kHz and a maximum acoustic intensity of 500 mW cm(-2) was applied continuously from 24 h till 72 h postsurgery on one of the two implanted discs. After euthanization and removal of the bacteria from the discs, the number of viable bacteria were quantified and skin samples were analysed for histopathological examination. Application of ultrasound, combined with gentamicin, reduced the viability of the biofilms in all three groups varying between 58 and 69% compared with the negative control. Histopathological examinations showed no skin lesions. CONCLUSIONS: Ultrasound resulted in a tendency of improved efficacy of gentamicin, either applied locally or systemically. Usage of ultrasound in this model proved to be safe. SIGNIFICANCE AND IMPACT OF THE STUDY: This study implies that ultrasound could improve the prevention of infection immediately after surgery, especially because the biomaterials, gentamicin and ultrasound used in this model are all in clinical usage, but not yet combined in clinical practice.

Animals↗

PubMed2003

Bacterial antibiotic resistance levels in Danish farmland as a result of treatment with pig manure slurry.

Resistance to tetracycline, macrolides and streptomycin was measured for a period of 8 months in soil bacteria obtained from farmland treated with pig manure slurry. This was done by spread plating bacteria on selective media (Luria Bertani (LB) medium supplemented with antibiotics). To account for seasonal variations in numbers of soil bacteria, ratios of resistant bacteria divided by total count on nonselective plates were calculated. Soil samples were collected from four different farms and from a control soil on a fifth farm. The control soil was not amended with animal manure. The occurrence of tetracycline-resistant bacteria was elevated after spread of pig manure slurry but declined throughout the sampling period to a level corresponding to the control soil. Higher load of pig manure slurry yielded higher occurrence of tetracycline resistance after spreading; however, the tetracycline resistance declined to normal occurrence defined by the tetracycline resistance occurrence in the control soil. Concentrations of tetracycline in soil and in pig manure slurry were measured using HPLC. No tetracycline exceeding the detection limit was found in soil samples. Manure slurry concentrations of tetracycline for three of the farms were 42, 81 and 698 microg/l, respectively. For streptomycin and macrolides, only minor variations in resistance levels were detected. Results obtained in this study thus indicate that tetracycline resistance levels in soil are temporarily influenced by the addition of pig manure slurry. The results indicate also that increased amount of pig manure slurry amendment may result in increased levels of tetracycline resistance in the soil.

Agriculture↗

PubMed2000

Phenotypic and molecular characterization of conjugative antibiotic resistance plasmids isolated from bacterial communities of activated sludge.

In order to isolate antibiotic resistance plasmids from bacterial communities found in activated sludge, derivatives of the 3-chlorobenzoate-degrading strain Pseudomonas sp. B13, tagged with the green fluorescent protein as an identification marker, were used as recipients in filter crosses. Transconjugants were selected on agar plates containing 3-chlorobenzoate as the sole carbon source and the antibiotic tetracycline, streptomycin or spectinomycin, and were recovered at frequencies in the range of 10(-5) to 10(-8) per recipient. A total of 12 distinct plasmids, designated pB1-pB12, was identified. Their sizes ranged between 41 to 69 kb and they conferred various patterns of antibiotic resistance on their hosts. Two of the plasmids, pB10 and pB11, also mediated resistance to inorganic mercury. Seven of the 12 plasmids were identified as broad-host-range plasmids, displaying extremely high transfer frequencies in filter crosses, ranging from 10(-1) to 10(-2) per recipient cell. Ten of the 12 plasmids belonged to the IncP incompatibility group, based on replicon typing using IncP group-specific PCR primers. DNA sequencing of PCR amplification products further revealed that eight of the 12 plasmids belonged to the IncPbeta subgroup, whereas two plasmids were identified as IncPalpha plasmids. Analysis of the IncP-specific PCR products revealed considerable differences among the IncPbeta plasmids at the DNA sequence level. In order to characterize the gene "load" of the IncP plasmids, restriction fragments were cloned and their DNA sequences established. A remarkable diversity of putative proteins encoded by these fragments was identified. Besides transposases and proteins involved in antibiotic resistance, two putative DNA invertases belonging to the Din family, a methyltransferase of a type I restriction/modification system, a superoxide dismutase, parts of a putative efflux system belonging to the RND family, and proteins of unknown function were identified.

DNA Restriction Enzymes↗