Preventive effects of a major component of green tea, epigallocathechin-3-gallate, on hepatitis-B virus DNA replication

BACKGROUND

Hepatitis B virus infection is one of the major world health problems. Epigallocatechin-3 gallate is the major component of the polyphenolic fraction of green tea and it has an anti-viral, anti-mutagenic, anti- tumorigenic, anti-angiogenic, anti-proliferative, and/or pro-apoptotic effects on mammalian cells. In this study, our aim was to investigate the inhibition of HBV replication by epigallocatechin-3 gallate in the Hep3B2.1-7 hepatocellular carcinoma cell line.

MATERIALS AND METHODS

HBV-replicating Hep3B2.1-7 cells were used to investigate the preventive effects of epigallocatechin-3 gallate on HBV DNA replication. The expression levels of HBsAg and HBeAg were determined using ELISA. Quantitative real-time-PCR was applied for the determination of the expression level of HBV DNA.

RESULTS

Cytotoxicity of epigallocathechin-3-gallate was not observed in the hepatic carcinoma cell line when the dose was lower than 100 μM. The ELISA method demonstrated that epigallocatechin-3 gallate have strong effects on HBsAg and HBeAg levels. Also it was detected by real-time PCR that epigallocatechin-3 gallate could prevent HBV DNA replication.

CONCLUSIONS

The obtained data pointed out that although the exact mechanism of HBV DNA replication and related diseases remains unclear, epigallocatechin-3 gallate has a potential as an effective anti-HBV agent with low toxicity.

Comparison of surface swab and quantitative biopsy cultures dependent on isolated microorganisms from burn wounds

OBJECTIVE

Infections are one of the most important and potentially serious complications of burn wounds. Quantitative biopsy cultures are useful for showing that a burn wound infection is not present, but these cultures are not useful for showing that an infection is present. Swab cultures are used to diagnosis surface colonization and may not accurately reflect the organism(s) causing the wound infection.

MATERIALS AND METHODS

To perform a comparison of surface swab and biopsy cultures for isolated microorganisms from burn wounds, 160 biopsy/surface swab pairs were collected from 160 patients.

RESULTS

Seventy-seven patients (48.1%) showed positive micro-organism cultures from the burn wounds; 19.3 percent had both positive surface cultures and significant bacterial counts from the biopsy cultures, whereas 28.8 percent of the patients had only positive surface cultures. There was moderate agreement (41%) between the results of surface swab and quantitative biopsy cultures used to diagnose burn wound infections. Pseudomonas aeruginosa (45.5%) was the most predominantly isolated bacteria from the wounds, and there was good concordance between the results of the surface swab and quantitative biopsy culture samples (78%). Coagulase-negative Staphylococci (CNS) and Escherichia coli strains were only isolated from the surface swab samples because they are colonizing bacteria. The univariate analysis revealed that there were significant associations between the results of the positive biopsy cultures and the total surface body area, open flame burns, prolonged hospitalization and female gender (p<0.05).

CONCLUSION

Surface swab and quantitative biopsy cultures have a high rate of concordance in predicting P. aeruginosa invasion and the colonization of E. coli and CNS strains in burn wounds.

Persistence of nosocomial pathogens on various fabrics

OBJECTIVE

Fabrics can become contaminated with high numbers of microorganisms that may be pathogenic to patients in a hospital setting and can play an important role in the chain of infection. The aim of this study was to investigate the survival of several clinical bacterial and fungal isolates on several fabrics commonly used in hospitals.

MATERIALS AND METHODS

Bacterial and fungal survival was tested on the following materials, each of which are commonly used in our hospital: 100% smooth cotton, 60% cotton-40% polyester, 100% wool and 100% silk. One isolate each of Candida albicans, Candida tropicalis, Candida krusei, Candida glabrata, Candida parapsilosis, Geotrichum candidum, Aspergillus fumigatus, Cryptococcus neoformans, vancomycin resistant Enterococcus faecium (VRE, methicillin-resistant Staphylococcus aureus (MRSA), extended-spectrum beta-lactamase (ESBL) positive Escherichia coli, inducible beta-lactamase (IBL) positive Pseudomonas aeruginosa, IBL-positive Acinetobacter baumannii and Stenotrophomonas maltophilia were used to contaminate fabrics. The survival of these microorganisms was studied by testing the fabric swatches for microbial growth.

RESULTS

The median survival times for all the tested bacteria and fungi were as follows: 26 days on cotton, 26.5 days on cotton-polyester, 28 days on silk, and 30 days on wool. Among the bacterial species tested, E. faecium had the longest survival time on cotton-polyester fabrics. For the fungal isolates, it was observed that C. tropicalis and C. krusei survived for the shortest amount of time on cotton fabrics in the present study.

CONCLUSION

This survival data indicate that pathogenic microorganisms can survive from days to months on commonly used hospital fabrics. These findings indicate that current recommendations for the proper disinfection or sterilization of fabrics used in hospitals should be followed to minimize cross-contamination and prevent nosocomial infections.

Incidence and risk factors of the secondary skin infections in patients with radiodermatitis

OBJECTIVE

The aim of this prospective study was to investigate the incidence and risk factors of secondary infected radiodermatitis in patients receiving radiotherapy and to determine isolated microorganisms' resistance profiles to different antimicrobial agents.

MATERIALS AND METHODS

The study comprised 62 patients admitted to the Regional Training and Research Hospital from January 2009 to January 2010. Radiodermatitis was graded according to the National Cancer Institute's Common Toxicity Criteria version 3.0. Potential risk factors for secondary infection were recorded and evaluated by univariate and multivariate analyses.

RESULTS

In 62 patients, grade 1, 2, 3 and 4 radiodermatitis were observed in 33 (53.2%), 11 (17.7%), 8 (12.9%) and 10 (16.2%) patients, respectively. Skin infection secondary to radiodermatitis occurred in 14 patients (infected patients), 21.4%, 21.4% and 57.2% of whom had grade 2, 3 and 4 radiodermatitis, respectively. Forty-eight patients were found to be colonized with micoorganisms (colonized patients). In the univariate analysis, concurrent endocrine therapy and radiodermatitis grade differed significantly between infected and colonized patients (p<0.05). Multivariate analyses showed that the radiodermatitis grade was an independent risk factor for the acquisition of infection (p<0.05). The microbial pathogens isolated from patients with skin infection were seven methicillin-resistant coagulase-negative Staphylococcus (MRCNS) strains, three methicillin-resistant Staphylococcus aureus (MRSA) strains, two Candida sp., one methicillin-sensitive coagulase-negative Staphylococcus (MSCNS) strain and one methicillin-sensitive S. aureus (MSSA) strain. Staphylococci strains were more resistant to beta-lactam antibiotics. No glycopeptide resistance was found.

CONCLUSION

The results of this study indicate that high-grade radiodermatitis leads to an increased risk for secondary infection of the skin with pathogens.

Prevalence of metallo-β-lactamase among Pseudomonas aeruginosa and Acinetobacter baumannii isolated from burn wounds and in vitro activities of antibiotic combinations against these isolates

The prevalence of metallo-beta-lactamases (MBLs) produced by isolates of Pseudomonas aeruginosa and Acinetobacter baumannii and the activities of various antmicrobial combinations against MBL producer strains were investigated. During the period from June 2003 till July 2004, 120 P. aeruginosa and 9 A. baumannii nonduplicate isolates were obtained from burn wounds. Forty strains (37 P. aeruginosa, 3 A. baumannii) were selected because of resistance to carbapenems. Screening for MBL production was performed in the latter isolates by the combined disk method which depends on comparing the zones given by disks containing imipenem with and without ethylenediaminetetraacetic acid (EDTA). Of imipenem resistant P. aeruginosa strains, 21 and 1 of A. baumannii were found metallo-beta-lactamase producers. Disk approximation studies were then performed to test for in vitro activities of various antimicrobial combinations. For a total of 21 P. aeruginosa strains, synergy was demonstrated predominantly by ciprofloxacin in combination with ceftazidime and imipenem, by ofloxacin in combination with astreonam. Against MBL producer A. baumannii strain, synergy was detected only with imipenem-ofloxacin combination. None of the combinations were antagonistic. These results suggest that MBL producing P. aeruginosa and A. baumanni strains have been introduced into burn centers, and to prevent the further spread of MBL producers, it is essential for carbapenem resistant isolates to be screened for MBLs.

The risk factors for acquisition of imipenem-resistant Pseudomonas aeruginosa in the burn unit

OBJECTIVE

This study was conducted to determine the risk factors for acquisition of imipenem-resistant Pseudomonas aeruginosa (IRPA) in the burn unit.

METHODS

Patients hospitalized in the burn unit from July 2003 to November 2004 were included in this study. The features of patients with isolated IRPA were compared with those of patients with isolated imipenem-susceptible P. aeruginosa (ISPA). Demographic features, total burn surface area (TBSA), burn depth, antimicrobials used in 15-day period before isolation, and presence of IRPA in the unit at the same period were included in the risk factors analysis.

RESULTS

P. aeruginosa was recovered from 133 patients in this period, 93 were IRPA and 40 were ISPA. There was no significant difference between patients with ISPA and patients with IRPA in terms of age, TBSA, and burn depth. In multivariate logistic regression analysis, hospital stay before isolation (odds ratio (OR): 3.6), carbapenem usage (OR: 7.4), broad-spectra antibiotic usage (OR: 6.5), previous presence of ISPA in the patient (OR: 1.7) and presence of IRPA in the unit at the same period (OR: 2.6) were independent risk factors for acquisition of IRPA.

CONCLUSION

Long hospitalization time, previous imipenem/meropenem use, previous broad-spectra antibiotic use, previous presence of ISPA in a patient and presence of IRPA in a unit at the same period were associated with acquisition of IRPA in the burn unit. In order to decrease the incidence of IRPA isolation, the usage of broad-spectra antibiotics, especially carbapenem, should be restricted, hospitalization time should be shortened if possible, and universal isolation precautions should be strictly applied to prevention cross-contamination.

Maternal carriage and neonatal colonisation of group B streptococcus in eastern Turkey: prevalence, risk factors and antimicrobial resistance

Our object is to determine the prevalence of group B streptococcus (GBS) carriage among pregnant women, the neonatal colonisation rate and the antimicrobial susceptibility to formulate a policy for treatment and prevention regarding perinatal GBS diseases in eastern Turkey. A total of 150 pregnant women were screened for GBS colonisation. Samples were collected from the vagina and the rectum of pregnant women, and the ear canal, throat and umbilicus of the neonates of colonised mothers. Antimicrobial susceptibility of the isolates was also investigated. GBS was isolated in at least one specimen from the 150 women in 48 cases; it was estimated that, overall, about 32% of the pregnant women and 17.3% of overall newborns were colonised with GBS. The overall rate of GBS vertical transmission was 54.2% in this study. Maternal colonisation rate was significantly higher in younger ages (p < 0.01) when maternal age of 20 years was taken as a cut-off point. All isolates were found to be sensitive to penicillin, ampicillin, cefazolin and vancomycin. Resistance to erythromycin and clindamycin were found to be 13.5 and 2.7%, respectively.

Slime factor positivity in coagulase negative staphylococci isolated from nasal samples of haemodialysis patients

Polysaccharide slime seems to be the most important factor by which coagulase negative staphylococci (CNS) strains adheres and colonises catheters. The aim of this study was to determine the prevalence of slime-producing CNS strains isolated from nasal samples of patients on haemodialysis and of healthy persons as a control. Nasal cultures were performed for 131 haemodialysis patients and 56 healthy persons. CNS strains were isolated from 86 of 131 patients (72.9%), and 46 of 56 healthy persons (82.1%). Twenty-four (27.9%) of the 86 CNS strains tested in the patient group and four (8.7%) of the 46 CNS strains in the control group were slime factor positive. There was a significant difference (p<0.01) in slime production between CNS strains isolated from haemodialysis patients and from control group. The detection of slime-producing coagulase-negative staphylococcus carriage in haemodialysis patients may prevent dialysis catheter-related coagulase-negative staphylococcal infections.

The time-related changes of antimicrobial resistance patterns and predominant bacterial profiles of burn wounds and body flora of burned patients

To examine the bacterial isolates from the burn patients and to compare the antibiograms of the predominant bacteria isolated from 51 patients who were hospitalized at least 3 weeks or more over a period of 7 months, a prospective study was undertaken. Periodic swabs were taken from burn wound, nasal, axillary, inguinal, and umbilical region of the patients on admission and on 7th, 14th, and 21st days of hospitalization. Mean hospital stay was 36.5 days. A total of 1098 microbial isolates were detected during the study period. Coagulase-negative staphylococci (CNS, 63.0%) and Staphylococcus aureus (19.7%) were the most prevalent isolates in admission cultures. During the next weeks, these bacteria were superceded by mainly Pseudomonas aeruginosa. Between admission and 21st day, the rates of methicillin resistance of staphylococci strains increased steadily. There was no vancomycin resistance in any staphylococci strains, although nine of the S. aureus isolates (2.7%) were resistant to teicoplanin. There were no strains producing inducible beta lactamase (IBL) among P. aeruginosa strains. One extended-spectrum beta-lactamase (ESBL)-producing strain was recovered on admission, although strains producing IBL and ESBL were detected at rates of 79.6 and 57.1%, respectively, on the 21st day. The nature of microbial wound colonization, flora changes, and antimicrobial sensitivity profiles should be taken into consideration in using empirical antimicrobial therapy of burned patients.

Changes of microbial flora and wound colonization in burned patients

To determine time related changes of microbial colonization of burn wounds and body flora of burned patients, a prospective study was carried out. Fifty-one patients who were hospitalized at least 3 weeks were enrolled in the study. Periodic swabs were taken from burn wound, nasal, axillary, inguinal, and umbilical regions of the patients on admission and 7th, 14th, and 21st days of hospitalization. The mean body surface area burned was 22.9%. A total of 1098 microbial isolates were detected during the study period. Coagulase-negative staphylococci (CNS, 63.0%) and Staphylococcus aureus (19.7%) were the most prevalent isolates in admission cultures. There was a gradual decrease in the number of isolates of CNS and a marked increase in the numbers of S. aureus and Pseudomonas aeruginosa from admission to 21st day. At the 21st day, the most frequent organisms were S. aureus (37.6%), CNS (34.7%), and P. aeruginosa (16.2%). Methicillin resistance of staphylococci strains were increased constantly in study period. While 35.3% of burn wounds were sterile on admission, microbial colonization reached 86.3% within the first week. Nasal carriage of methicillin resistant S. aureus increased from 3.9% to 62.7% at 21st day. The nature of microbial wound colonization and flora changes should be taken into consideration in empirical antimicrobial therapy of burned patients.

Demonstration of in vitro antagonism between fusidic acid and quinolones

Fusidic acid is an antibiotic active against staphylococci and other bacterial pathogens. It is used in the treatment of staphylococcal infections usually in combination with other antibacterial agents. Reports of the clinical effects of antimicrobial combinations containing fusidic acid have been somewhat inconsistent. The aim of this study was to investigate the in vitro antagonism of fusidic acid and quinolones. Twenty-six staphylococci strains isolated from various clinical samples were tested. After detecting the diameter of the zone of inhibition around fusidic acid, levofloxacin, ciprofloxacin, ofloxacin and moxifloxacin for each strain, in vitro antagonism between fusidic acid and each quinolone was investigated using disk approximation. In all 26 strains, quinolones and fusidic acid were antagonist in vitro. The reason for this antagonistic effect and its clinical implications are not known. However, care should be exercised in prescribing quinolones and fusidic acid in combination.