Quorum sensing enables bacteria to control the gene expression in response to the cell density. It regulates a variety of bacterial physiological functions such as biofilm formation, bioluminescence, virulence factors and swarming which has been shown contribute to bacterial pathogenesis. The use of quorum sensing inhibitor would be of particular interest in treating bacterial pathogenicity and infections. In this work, we have tested caffeine as quorum sensing inhibitor by using Chromobacterium violaceum CV026 as a biosensor. We verified that caffeine did not degrade the N-acyl homoserine lactones tested. In this work, it is shown that caffeine could inhibit N-acyl homoserine lactone production and swarming of a human opportunistic pathogen, namely Pseudomonas aeruginosa PA01. To the best of our knowledge, this is the first documentation providing evidence on the presence of anti-quorum sensing activity in caffeine. Our work will allow caffeine to be explored as anti-infective drugs.
In this study we investigated the relationship between several selected commercially available essential oils and beta-lactam antibiotics on their antibacterial effect against multidrug resistant bacteria. The antibacterial activity of essential oils and antibiotics was assessed using broth microdilution. The combined effects between essential oils of cinnamon bark, lavender, marjoram, tea tree, peppermint and ampicillin, piperacillin, cefazolin, cefuroxime, carbenicillin, ceftazidime, meropenem, were evaluated by means of the checkerboard method against beta-lactamase-producing Escherichia coli. In the latter assays, fractional inhibitory concentration (FIC) values were calculated to characterize interaction between the combinations. Substantial susceptibility of the bacteria toward natural antibiotics and a considerable reduction in the minimum inhibitory concentrations (MIC) of the antibiotics were noted in some paired combinations of antibiotics and essential oils. Out of 35 antibiotic-essential oil pairs tested, four of them showed synergistic effect (FIC≤0.5) and 31 pairs showed no interaction (FIC>0.5-4.0). The preliminary results obtained highlighted the occurrence of a pronounced synergistic relationship between piperacillin/cinnamon bark oil, piperacillin/lavender oil, piperacillin/peppermint oil as well as meropenem/peppermint oil against two of the three bacteria under study with a FIC index in the range 0.26-0.5. The finding highlighted the potential of peppermint, cinnamon bark and lavender essential oils being as antibiotic resistance modifying agent. Reduced usage of antibiotics could be employed as a treatment strategy to decrease the adverse effects and possibly to reverse the beta-lactam antibiotic resistance.
The in vitro antibacterial and antibiofilm activity of chlorogenic acid against clinical isolates of Stenotrophomonas maltophilia was investigated through disk diffusion, minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), time-kill and biofilm assays. A total of 9 clinical S. maltophilia isolates including one isolate resistant to trimethoprim/sulfamethoxazole (TMP/SMX) were tested. The inhibition zone sizes for the isolates ranged from 17 to 29 mm, while the MIC and MBC values ranged from 8 to 16 μg mL(-1) and 16 to 32 μg mL(-1). Chlorogenic acid appeared to be strongly bactericidal at 4x MIC, with a 2-log reduction in viable bacteria at 10 h. In vitro antibiofilm testing showed a 4-fold reduction in biofilm viability at 4x MIC compared to 1x MIC values (0.085 < 0.397 A 490 nm) of chlorogenic acid. The data from this study support the notion that the chlorogenic acid has promising in vitro antibacterial and antibiofilm activities against S. maltophilia.
A simple and selective RP-HPLC-UV method with SPE was developed and validated for the quantification of cefotaxime in all-in-one total parenteral nutrition (AIO-TPN) admixtures. Chromatographic separation was achieved on a 5 pm particle size C18 DB column (250 x 4.6 mm id) using the mobile phase ammonium acetate (25 mM, pH 4.0)-50% acetonitrile in methanol (80 + 20, v/v). The flow rate was 0.9 mL/min and the detection wavelength was 254 nm. The analyte was extracted from AIO-TPN admixtures by means of an SPE method. The cefotaxime calibration curve was linear over a concentration range of 100-1400 microg/mL with a correlation coefficient of > or = 0.9994. The intraday accuracy and precision for cefotaxime were < or = -3.15 and < or = 3.08%, respectively, whereas the interday accuracy and precision were < or = -2.48 and < or = 2.25%, respectively. The method was successfully applied to stability studies of cefotaxime in the presence of micronutrients together with low and high concentrations of macronutrients in AIO-TPN admixtures. Cefotaxime was degraded by 13.00 and 26.05% at room temperature (25 +/- 2 degrees C) after 72 h in low and high macronutrient concentration formulations of AIO-TPN admixtures, respectively. The values of cefotaxime degradation rates for low and high macronutrient concentration formulations of AIO-TPN admixtures were -0.164 and -0.353, respectively. These results indicated that there was a higher rate of degradation in the AIO-TPN admixture formulations containing high concentrations of macronutrients.
The present study served to gain further insight into the bactericidal effects of ellagitannins from Acalypha wilkesiana var. macafeana hort. against pathogenic bacteria. Ellagitannins from the aerial parts of A. wilkesiana var. macafeana hort. (EAW) inhibited the growth of Bacillus cereus (ATCC 11778), Bacillus subtilis (ATCC 6633), Staphylococcus aureus (ATCC 11632) and Methicillin-resistant Staphylococcus aureus (MRSA) clinical strain with inhibition zones equal to 11.01 ± 1.53 mm, 16.63 ± 0.11 mm, 11.40 ± 1.10 mm and 8.22 ± 0.19 mm, respectively. The minimal inhibition concentration and the minimal bactericidal concentration of ellagitannins from A. wilkesiana var. macafeana hort. (EAW) against MRSA were 750 µg/mL and 3000 µg/mL, respectively. We then examined the synergistic effect of EAW with three antibiotics, i.e. ampicillin, streptomycin and tetracycline, via the checkerboard assay and time-kill assay and observed that EAW is synergistic with ampicillin against S. aureus (ATCC 11632). Environmental electron scanning microscopy analysis showed cell lysis against S. aureus (ATCC 11632) upon treatment with the ellagitannin fraction. The ellagitannin fraction from A. wilkesiana var. macafeana hort. is bactericidal against gram-positive bacteria tested and works synergistically with ampicillin against S. aureus. Morphology analysis of the cell suggests that the bactericidal property of the ellagitannin fraction mechanism involves lysis of the cell wall. In summary, our studies demonstrate that A. wilkesiana var. macafeana hort. produces bactericidal ellagitannins of clinical and/or cosmetological value.
Lemierre syndrome is an uncommon disease which commonly arise from acute bacterial oropharyngeal infection. This disease was first described in 1900 by Courmont and Cade Lemierre. It is commonly caused by Fusobacterium necrophorum. Lemierre syndrome has been reported to be serious and potentially fatal in the preantibiotic era. It is characterized by an oropharyngeal infection leading to secondary septic thrombophlebitis of the internal jugular vein with embolization to the lungs and other organs. The incidence has become relatively rare at present and is usually only diagnosed when unsuspected culture results are available. We report a case of Lemierre syndrome which was recently diagnosed in our centre.
This study evaluated in vitro activity of 9 flavonoids in combination with vancomycin or oxacillin against vancomycin-intermediate Staphylococcus aureus (VISA) ATCC 700699 by employing the checkerboard method to obtain Minimal inhibitory concentration (MIC) and fractional inhibitory concentration (FIC) index. Six flavonoids namely hesperitin, rutin, naringenin, flavones, naringin and 3, 7-dihyroxyflavone which exhibited notable inhibitory activity (MIC values < 3200 μg/ml) were further evaluated for combination assay with antibiotics. The combinations of vancomycin+flavone and oxacillin+flavone were found synergistic with the FIC index value 0.094 and 0.126, respectively. Other combinations showed an additive interaction (FIC index = 1.063) but no antagonistic reaction (FIC index > 4) were observed. In time kill studies, oxacillin-flavone combination at synergistic concentration demonstrated bactericidal effect at 24 h period with concentration-dependent manner on the VISA strain. Following 1 h exposure, the combination also produced persistent effect on the bacteria growth for 2.9 hrs at 1x sub-MIC and more than 24 h at 5x of sub-MIC and there was a significant difference between both concentrations (p<0.05). Vancomycin-flavone combination, however, showed no concentration-dependent effect and lower PAE values (1.159 h and 2.322 h at 1x and 5x sub-MIC, respectively) on the VISA strain. In conclusion, flavone markedly intensifies the susceptibility of oxacillin against VISA and the combination can be implicated for further interaction studies at molecular level.
The prevalence of antibiotic resistance varies in geographic areas. The information on the antibiotic susceptibility patterns of Helicobacter pylori (H. pylori) in our local setting is therefore relevant as a guide for the treatment options.
A capillary electrophoretic method for the separation of the enantiomers of both ofloxacin and ornidazole is described. Several parameters affecting the separation were studied, including the type and concentration of chiral selector, buffer pH, voltage and temperature. Good chiral separation of the racemic mixtures was achieved in less than 16 min with resolution factors Rs=5.45 and 6.28 for ofloxacin and ornidazole enantiomers, respectively. Separation was conducted using a bare fused-silica capillary and a background electrolyte (BGE) of 50 mM H(3)PO(4)-1 M tris solution; pH 1.85; containing 30 mg mL(-1) of sulfated-beta-cyclodextrin (S-beta-CD). The separation was carried out in reversed polarity mode at 25 degrees C, 18 kV, detection wavelength at 230 nm and using hydrodynamic injection for 15 s. Acceptable validation criteria for selectivity, linearity, precision, and accuracy were studied. The limits of detection (LOD) and limits of quantitation (LOQ) of the enantiomers (ofloxacin enantiomer 1 (OF-E1), ofloxacin enantiomer 2 (OF-E2), ornidazole enantiomer 1 (OR-E1) and ornidazole enantiomer 2 (OR-E2)) were (0.52, 0.46, 0.54, 0.89) and (1.59, 1.40, 3.07, 2.70) microg mL(-1), respectively. The proposed method was successfully applied to the assay of enantiomers of both ofloxacin and ornidazole in pharmaceutical formulations. The computational calculations for the enantiomeric inclusion complexes rationalized the reasons for the different migration times between the ofloxacin and ornidazole enantiomers.
Acute sinusitis is most often a mild self-limiting disease. However, it may progress into severe and life threatening complications. One of the commonest being orbital complication of which visual loss is a direct consequence. In this 10 year retrospective study, the nature of orbital complication, clinical presentation and treatment modalities and outcome seen in children with acute sinusitis in a tertiary referral institute were reviewed. Of six patients, there was a case of preseptal cellulitis, 4 cases of subperiosteal abscess and one case of orbital abscess. Periorbital swelling was a common presenting feature. In 5 cases this was associated with proptosis with one case of impending optic nerve compression. The value of computed tomography and opthalmological examination as a component in the management plan is highlighted. All patients were treated with intravenous antibiotics but evidence of abscess collection warranted urgent surgical drainage in 5 patients, 3 being endoscopic drainage while external approach was done for the remaining 2 patients. Thus a child exhibiting orbital complication of acute sinusitis, prompt diagnosis and treatment is essential in obtaining the best outcome for the child.
Matched MeSH terms: Anti-Bacterial Agents/therapeutic use
Acute exacerbations of chronic obstructive pulmonary disease (COPD) are important events in COPD patients and place a large burden on healthcare resources. COPD patients with frequent exacerbations have accelerated decline in lung function, poorer health status and are at higher risk of mortality. The mainstay of treatment includes increasing short acting bronchodilator therapy and systemic glucocorticosteroids with or without antibiotics. Non invasive ventilation is indicated in those with respiratory failure with acidosis or hypercapnia. Preventive strategies to reduce exacerbations include smoking cessation, immunisation against influenza and S. pneumonia, chronic maintenance inhaled pharmacotherapy, pulmonary rehabilitation and self management education.
Matched MeSH terms: Anti-Bacterial Agents/therapeutic use
Endophytes, which are receiving increasing attention, have been found to be potential sources of bioactive metabolites following the discovery of paclitaxel producing endophytic fungi. In the present study, a total of 348 endophytes were isolated from different parts of 24 Malaysian medicinal plants. Three selected endophytes (HAB10R12, HAB11R3 and HAB21F25) were investigated for their antimicrobial and cytotoxic activities. For antimicrobial activity, HAB10R12 and HAB11R3 were found to be most active against bacteria and fungi, respectively. Their antimicrobial effects were comparable to, if not better than, a number of current commercial antibacterial and antifungal agents. Both HAB10R12 and HAB21F25 were found to be potential anticancer drug candidates, having potent activity against MCF-7 and HCT116 cell lines and warrant further investigation.
A simple, rapid and validated capillary electrophoretic method has been developed for the separation and determination of ofloxacin and ornidazole in pharmaceutical formulations with detection at 230 nm. Optimal conditions for the quantitative separations were investigated. Analysis times shorter than 4 min were obtained using a background electrolyte solution consisting of 25 mmol/L phosphoric acid adjusted with 1 M Tris buffer to pH 8.5, with hydrodynamic injection of 5 s and 20 kV separation voltage. The validation criteria for accuracy, precision, linearity and limits of detection and quantitation were examined and discussed. An excellent linearity was obtained in concentration range 25-250 microg/mL. The detection limits for ofloxacin and ornidazole were 1.03 +/- 0.11 and 1.80 +/- 0.06 microg/mL, respectively. The proposed method has been applied for the analysis of ofloxacin and ornidazole both individually and in a combined dosage tablet formulation. The proposed validated method showed recoveries between 96.16 and 105.23% of the nominal contents.
A 64-year old patient, who had bacteraemia, did not respond to vancomycin despite the MRSA isolate being sensitive to the antibiotic at MIC 2 microg/mL. Electron microscopy of the MRSA isolate showed thickening of the cell wall, which was not observed in MRSA with lower vancomycin MIC.
Group B streptococcus (GBS) is a leading cause of neonatal sepsis and is usually acquired via the woman's birth canal. GBS serotypes isolated from 200 pregnant women were determined. Serotypes V (19%) and VI (17%) were the most frequent followed by serotypes III (12%), Ia (11.5%) and IV (10%); 17% of the strains were non-typable. All isolates were susceptible to penicillin, 96% to erythromycin and 97.5% to clindamycin. The emergence of new GBS serotypes has important implications for vaccine prevention strategies.
The clinical outcome of bacteraemic patients is influenced by many factors. It is vital to know one's own local hospital epidemiological data so as to provide optimal care to the affected patients. This was a prospective, observational study carried out in the said patient population over a period of four months in the year 2005. One hundred and ninety one patients presented with bacteraemia over the study period. Fifty-two (27%) of the patients died. Mechanical ventilation, inappropriate empirical antibiotic usage, Chinese ethnicity and low serum albumin levels independently affected prognosis. These factors should alert physicians to those patients who require more intensive monitoring and care.
KEY WORDS:
Bacteraemia, Blood Culture Positive, Outcome, Risk factors, Kuala Lumpur, Malaysia
Matched MeSH terms: Anti-Bacterial Agents/therapeutic use
BACKGROUND: Mastitis can be caused by ineffective positioning of the baby at the breast or restricted feeding. Infective mastitis is commonly caused by Staphylococcus Aureus. Incidence of mastitis in breastfeeding women may reach 33%. Effective milk removal, pain medication and antibiotic therapy have been the mainstays of treatment.
OBJECTIVES: This review aims to examine the effectiveness of antibiotic therapies in relieving symptoms for breastfeeding women with mastitis with or without laboratory investigation.
SEARCH STRATEGY: We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (December 2007), the Cochrane Central Register of Clinical Trials (The Cochrane Library 2007, Issue 4), MEDLINE (1996 to 2007) and EMBASE (January 1985 to 2007). We contacted investigators and other content experts known to us for unpublished trials and scanned the reference lists of retrieved articles
SELECTION CRITERIA: Randomized and quasi-randomized clinical trials comparing the effectiveness of various types of antibiotic therapies or antibiotic therapy versus alternative therapies for the treatment of mastitis were selected.
DATA COLLECTION AND ANALYSIS: Two authors independently assessed trial quality and extracted data. When in dispute, we consulted a third author.
MAIN RESULTS: Two trials met the inclusion criteria. One small trial (n = 25) compared amoxicillin with cephradine and found no significant difference between the two antibiotics in terms of symptom relief and abscess formation. Another, older study compared breast emptying alone as "supportive therapy" versus antibiotic therapy plus supportive therapy, and no therapy. The findings of the latter study suggested faster clearance of symptoms for women using antibiotics, although the study design was problematic.
AUTHORS' CONCLUSIONS: There is insufficient evidence to confirm or refute the effectiveness of antibiotic therapy for the treatment of lactational mastitis. There is an urgent need to conduct high-quality, double-blinded randomized clinical trials to determine whether antibiotics should be used in this common postpartum condition.
Invasive Neisseria meningitidis infection is rare but carries a high mortality rate. The carriage rate in the normal population is around 10% and can be higher in confined populations. A study on the prevalence of carriage of N. meningitidis was conducted among 3195 army recruits after 2 months of intensive training in an army camp. N. meningitidis was isolated from 37.0% of these recruits. Two hundred and ten of N. meningitidis isolates were subjected to serogrouping and 100 to antibiotic sensitivity testing by the disc diffusion method and E-test for penicillin. Ten (4.8%) of 210 Neisseria meningitidis serogrouped belonged to serogroup W135, 3.33% serogroup A and 81.4% belonged to either serogroup X, Y or Z. With the agar disc diffusion method, all the N. meningitidis showed susceptiblity to chloramphenicol, rifampicin, cefotaxime and levofloxacin; 85% of the strains were resistant to cotrimoxazole and 12.5% resistant to penicillin. However, based on minimum inhibitory concentration, none of the Neisseria meningitidis tested was resistant to penicillin.