Impact of iron chelators on growth and expression of iron-related genes of Cryptococcus species.

INTRODUCTION: Iron chelator has previously demonstrated fungicidal effects. This study aimed to investigate the antifungal activity of the iron chelators deferoxamine (DFO) and deferasirox (DSX) against Cryptococcus. MATERIALS AND METHODS: Cryptococcus neoformans and Cryptococcus gattii were used to determine the minimal inhibitory concentrations (MICs) of DFO and DSX, and the fractional inhibitory concentration index (FICI) of DFO and DSX when combined with amphotericin B (AMB). Expression of cryptococcal CFT1, CFT2, and CIR1 genes was determined using real-time polymerase chain reaction (PCR). RESULTS: Neither DFO nor DSX alone showed antifungal activity against Cryptococcus strains. When combined with AMB, the MICs of DFO and DSX decreased from>200µg/mL to 6.25 or 12.5µg/mL. The MIC of AMB decreased one-fold dilution in most strains when combined with iron chelators. The FICI of DFO+AMB and DSX+AMB was 0.5 and 1, respectively. C. neoformans showed significant growth retardation when incubated with a combination of sub-MIC concentrations of AMB and DFO; whereas, C. gattii demonstrated lesser growth retardation in DFO+AMB. No cryptococcal growth retardation was observed when DSX was combined with AMB. When C. neoformans was grown in DFO, the CFT1, CFT2, and CIR1 proteins were expressed 1.7, 2.0, and 0.9 times, respectively. When C. neoformans was grown in DSX, the CFT1, CFT2, and CIR1 genes were expressed 0.5, 0.6, and 0.3 times, respectively. CONCLUSION: Synergistic antifungal activity of combination DFO and AMB was observed in Cryptococcus. Relatively increased CFT1 and CFT2 expression may be associated with the effect of DFO that inhibits the growth of fungi.

Prospective multinational serosurveillance study of Bordetella pertussis infection among 10- to 18-year-old Asian children and adolescents.

OBJECTIVES: Bordetella pertussis continues to cause outbreaks worldwide. To assess the role of children and adolescent in transmission of pertussis in Asia, we performed a multinational serosurveillance study. METHODS: From July 2013 to June 2016, individuals aged 10 to 18 years who had not received any pertussis-containing vaccine within the prior year were recruited in 10 centres in Asia. Serum anti-pertussis toxin (PT) IgG was measured by ELISA. Demographic data and medical histories were obtained. In the absence of pertussis immunization, anti-PT IgG ≥62.5 IU/mL was interpreted as B. pertussis infection within 12 months prior, among them levels ≥125 IU/mL were further identified as infection within 6 months. RESULTS: A total of 1802 individuals were enrolled. Anti-PT IgG geometric mean concentration was 4.5, and 87 (4.8%) individuals had levels ≥62.5 IU/mL; among them, 73 (83.9%) had received three or more doses of pertussis vaccine before age 6 years. Of 30 participants with persistent cough during the past 6 months, one (3.3%) had level ≥125 IU/mL. There was no significant difference in proportions with anti-PT IgG ≥62.5 IU/mL among age groups (13-15 vs. 10-12 years, 16-18 vs. 10-12 years), between types of diphtheria, pertussis and tetanus (DTP; whole cell vs. acellular), number of doses before age 6 years within the DTP whole-cell pertussis vaccine (five vs. four doses) or acellular pertussis vaccine (five vs. four doses) and history of persistent cough during the past 6 months (yes vs. no). CONCLUSIONS: There is significant circulation of B. pertussis amongst Asian children and adolescents, with one in 20 having serologic evidence of recent infection regardless of vaccination background.

Developing core elements and checklist items for global hospital antimicrobial stewardship programmes: a consensus approach.

OBJECTIVES: With increasing global interest in hospital antimicrobial stewardship (AMS) programmes, there is a strong demand for core elements of AMS to be clearly defined on the basis of principles of effectiveness and affordability. To date, efforts to identify such core elements have been limited to Europe, Australia, and North America. The aim of this study was to develop a set of core elements and their related checklist items for AMS programmes that should be present in all hospitals worldwide, regardless of resource availability. METHODS: A literature review was performed by searching Medline and relevant websites to retrieve a list of core elements and items that could have global relevance. These core elements and items were evaluated by an international group of AMS experts using a structured modified Delphi consensus procedure, using two-phased online in-depth questionnaires. RESULTS: The literature review identified seven core elements and their related 29 checklist items from 48 references. Fifteen experts from 13 countries in six continents participated in the consensus procedure. Ultimately, all seven core elements were retained, as well as 28 of the initial checklist items plus one that was newly suggested, all with ≥80% agreement; 20 elements and items were rephrased. CONCLUSIONS: This consensus on core elements for hospital AMS programmes is relevant to both high- and low-to-middle-income countries and could facilitate the development of national AMS stewardship guidelines and adoption by healthcare settings worldwide.

Collateral damage of using colistin in hospitalized patients on emergence of colistin-resistant Escherichia coli and Klebsiella pneumoniae colonization and infection.

Background: Colistin has been used for therapy of carbapenem-resistant Gram-negative infections in Thailand, especially carbapenem-resistant A. baumannii and P. aeruginosa, for more than 10 years. However, the prevalence of colistin-resistant A. baumannii or P. aeruginosa is still less than 5%. Colistin-resistant Enterobacteriaceae has been increasingly reported globally over the past few years and the use of colistin in food animals might be associated with an emergence of colistin resistance in Enterobacteriaceae. This study aimed to determine the effect of colistin exposure in hospitalized patients who received colistin on development of colistin-resistant (CoR) Escherichia coli (EC) or Klebsiella pneumoniae (KP) colonization and infection. Methods: A prospective observational study was performed in adult hospitalized patients at Siriraj Hospital who received colistin for treatment of infections during December 2016 and November 2017. The surveillance culture samples were collected from the stool and the site of infection of each patient who received colistin at the study enrollment, days 3 and 7 after the study enrollment, and once a week thereafter for determination of CoR EC and CoR KP. CoR EC and CoR KP were also tested for a presence of mcr-1 gene. Results: One hundred thirty-nine patients were included. Overall prevalence of CoR EC or CoR KP colonization was 47.5% among 139 subjects. Prevalence of CoR EC or CoR KP colonization was 17.3% of subjects at study enrollment, and 30.2% after study enrollment. Use of fluoroquinolones, aminoglycosides, and colistin was found to be significantly associated with CoR EC or CoR KP colonization. The mcr-1 gene was detected in 13.0% of CoR EC or CoR KP isolates, and in 27.3% of subjects with CoR EC or CoR KP colonization. CoR EC or CoR KP colonization persisted in 65.2% of the subjects at the end of the study. Five patients with CoR KP infections received combination antibiotics and they were alive at hospital discharge. Conclusions: Prevalence of CoR EC or CoR KP colonization in hospitalized patients receiving colistin was high and it was associated with the use of colistin. Therefore, patients who receive colistin are at risk of developing CoR EC or CoR KP colonization and infection.

Proposed primary endpoints for use in clinical trials that compare treatment options for bloodstream infection in adults: a consensus definition.

OBJECTIVES: To define standardized endpoints to aid the design of trials that compare antibiotic therapies for bloodstream infections (BSI). METHODS: Prospective studies, randomized trials or registered protocols comparing antibiotic therapies for BSI, published from 2005 to 2016, were reviewed. Consensus endpoints for BSI studies were defined using a modified Delphi process. RESULTS: Different primary and secondary endpoints were defined for pilot (small-scale studies designed to evaluate protocol design, feasibility and implementation) and definitive trials (larger-scale studies designed to test hypotheses and influence clinical practice), as well as for Staphylococcus aureus and Gram-negative BSI. For pilot studies of S. aureus BSI, a primary outcome of success at day 7 was defined by: survival, resolution of fever, stable/improved Sequential Organ Failure Assessment (SOFA) score and clearance of blood cultures, with no microbiologically confirmed failure up to 90 days. For definitive S. aureus BSI studies, a primary outcome of success at 90 days was defined by survival and no microbiologically confirmed failure. For pilot studies of Gram-negative BSI, a primary outcome of success at day 7 was defined by: survival, resolution of fever and symptoms related to BSI source, stable or improved SOFA score and negative blood cultures. For definitive Gram-negative BSI studies, a primary outcome of survival at 90 days supported by a secondary outcome of success at day 7 (as previously defined) was agreed. CONCLUSIONS: These endpoints provide a framework to aid future trial design. Further work will be required to validate these endpoints with respect to patient-centred clinical outcomes.

Association of levofloxacin resistance with mortality in adult patients with invasive pneumococcal diseases: a post hoc analysis of a prospective cohort.

OBJECTIVE: This study was conducted to identify risk factors for mortality and to evaluate the impact of antimicrobial resistance on outcome in adult patients with invasive pneumococcal disease (IPD). METHODS: A post hoc analysis of an observational cohort study on community-acquired pneumococcal infections was conducted and a total of 136 adult patients with IPD were analyzed in this study. RESULTS: Pneumonia was the most common type of infection (n = 84, 61.8 %), followed by primary bacteremia (n = 15, 11.0 %) and meningitis (n = 15, 11.0 %). One hundred and three patients (75.7 %) had concomitant pneumococcal bacteremia. The overall 30-day mortality rate was 26.5 % (36/136), and factors associated with 30-day mortality were corticosteroid use, presentation with septic shock, and development of acute respiratory distress syndrome (ARDS) (all P < 0.05). While penicillin and erythromycin resistance were associated with a lower mortality, an association between levofloxacin resistance and increased mortality was found in the univariate analysis; however, statistical significance was not reached (P = 0.083). Multivariable analysis showed that presentation with septic shock, corticosteroid use, development of ARDS, and levofloxacin resistance were independent factors associated with 30-day mortality. Of the five patients with IPD caused by levofloxacin-resistant Streptococcus pneumoniae, three (60 %) died within 30 days of diagnosis. CONCLUSION: Levofloxacin resistance was associated with increased mortality, along with septic shock, prior use of corticosteroids, and development of ARDS, in adult patients with IPD. Our data suggest that the emergence of levofloxacin resistance among invasive pneumococcal isolates is now becoming a challenge for clinicians managing community-acquired bacterial infections.

Population pharmacokinetics of colistin methanesulfonate and formed colistin in critically ill patients from a multicenter study provide dosing suggestions for various categories of patients.

With increasing clinical emergence of multidrug-resistant Gram-negative pathogens and the paucity of new agents to combat these infections, colistin (administered as its inactive prodrug colistin methanesulfonate [CMS]) has reemerged as a treatment option, especially for critically ill patients. There has been a dearth of pharmacokinetic (PK) data available to guide dosing in critically ill patients, including those on renal replacement therapy. In an ongoing study to develop a population PK model for CMS and colistin, 105 patients have been studied to date; these included 12 patients on hemodialysis and 4 on continuous renal replacement therapy. For patients not on renal replacement, there was a wide variance in creatinine clearance, ranging from 3 to 169 ml/min/1.73 m(2). Each patient was treated with a physician-selected CMS dosage regimen, and 8 blood samples for PK analysis were collected across a dosage interval on day 3 or 4 of therapy. A linear PK model with two compartments for CMS and one compartment for formed colistin best described the data. Covariates included creatinine clearance on the total clearance of CMS and colistin, as well as body weight on the central volume of CMS. Model-fitted parameter estimates were used to derive suggested loading and maintenance dosing regimens for various categories of patients, including those on hemodialysis and continuous renal replacement. Based on our current understanding of colistin PK and pharmacodynamic relationships, colistin may best be used as part of a highly active combination, especially for patients with moderate to good renal function and/or for organisms with MICs of ≥ 1.0 mg/liter.

Body composition: gender-specific risk factor of reduced quantitative ultrasound measures in older people.

INTRODUCTION: Body composition has been reported as a significant determinant of bone mineral density. However, data regarding the relationship between the body composition and quantitative ultrasound (QUS) are scarce. METHODS: This cross-sectional study examined risk factors of reduced QUS measures in older men and women. A total of 699 subjects aged 60 years old and over-458 women and 241 men-who lived in rural communities of Thailand were randomly recruited. RESULTS: By using broadband ultrasound attenuation at the cutoff point of mean -1.0 SD based on young Thai people, the independent factors associated with reduced QUS measures in men were: poor activity of daily living, older age, and low fat mass. As for older women, the independent factors were the number of years since menopause, lack of regular exercise, lower height, and low fat mass. When using the stiffness index at the cutoff point of mean -1.6 SD based on young Thai people, the independent factors associated with reduced QUS measures in men were older age and low fat mass. Meanwhile, the number of years since menopause and low lean body mass were independent risk factors in women. CONCLUSIONS: Poor activity of daily living in men or lack of regular exercise in women was found to be a modifiable risk factor of reduced QUS measures. Years since menopause and low lean body mass were significant factors determining reduced QUS measures in women. Fat mass was an independent factor associated with reduced QUS measures both in men and women.

Ribotyping of Burkholderia pseudomallei from clinical and soil isolates in Thailand.

Burkholderia pseudomallei is a soil saprophyte that causes melioidosis in humans and animals. Restriction fragment length polymorphism of the ribosomal DNA regions (ribotyping) were analyzed in 577 isolates comprising 371 clinical and 206 soil isolates collected throughout Thailand in 1997. A total of 77 distinct ribotype patterns consisting of 2-9 bands with sizes ranging from 2.8 to >23 kb were found. Twelve major ribotypes were identified of which types 3, 8 and 23 were commonly found (278/577, 48.2%) in both clinical (217/371, 58.5%) and environmental isolates (61/206, 29.6%). Three unique environmental types were found whereas a unique clinical type was not observed. Even though ribotypes show high heterogeneity in the rDNA region, the unique environmental patterns were clearly different from the clinical patterns as clearly seen by UPGMA dendrogram. Moreover, the three major types (types 3, 8 and 23) were discovered in nearly half of B. pseudomallei isolates. Subtyping of these major ribotypes in correlation with clinical profiles may help researchers to identify the virulence factor of the organism.

Bacterial infections in hospitalized patients in Thailand in 1997 and 2000.

Two surveys to determine the patterns of bacterial infections and trends in resistance to antibiotics of bacteria causing infections in patients admitted to hospitals in Thailand were conducted in 36 and 37 hospitals throughout Thailand in June 1997 and February 2000. Approximately 50 per cent of infections in hospitalized patients in Thailand were hospital-acquired infections. Urinary tract and lower respiratory tract were the most common sites of infections. Eighty per cent of infections were caused by gram negative bacteria. Gram negative bacteria causing infections in 2000 were more resistant to most commonly used antibiotics when compared with those in 1997. The prevalence of gram positive bacteria causing hospital-acquired infections significantly increased during this period. The trend of increase in resistance in most gram positive bacteria in 2000 was not clearly observed.

Microbial killing activity of peracetic acid.

In vitro killing activity of peracetic acid (Perasafe) at a concentration of 0.26 per cent w/v was tested against Escherichia coli, Enterobacter cloacae, Klebsiella pneumoniae, Pseudomonas aeruginosa, Salmonella typhi, Salmonella paratyphi A, Acinetobacter baumannii, Sternotrophomonas maltophilia, Enterococcus faecium, Enterococcus faecalis, methicillin-resistant Staphylococcus aureus (MRSA), Bacillus subtilis spore, Mycobacterium tuberculosis and human immuno-deficiency virus type I. Exposure to Peracetic acid (0.26% w/v) for 10 minutes resulted in massive killing of all the aforementioned organisms and spore.

Genotype analysis of Burkholderia pseudomallei using randomly amplified polymorphic DNA (RAPD): indicative of genetic differences amongst environmental and clinical isolates.

Burkholderia pseudomallei is the causative agent of melioidosis, an infectious disease common in the tropics. Melioidosis is most prevalent in the northeastern part of Thailand. The diseases has diverse clinical manifestations ranging from mild localized to fatal septicemic forms. The bacterial genetic factors contributing to the severity of melioidosis have not been completely identified. We have developed a genotyping method based upon randomly amplified polymorphic DNA (RAPD) analysis. Eighteen deca-oligo nucleotide primers with 70% GC content, eight previously published 60%GC RAPD primers, and four random deca oligomers were tested on nine strains of B. pseudomallei isolated from five patients with localized and four with septicemic melioidosis. The RAPD patterns were analyzed by polyacrylamide gel electrophoresis using a laser based automated fragment analyzer, GS2000. Based upon the pattern complexity, seven pairs consisting of eight primers were chosen for further analysis. Six hundred and thirty-two samples, including duplicates/triplicates, of B. pseudomallei isolated from melioidosis patients and the environment were analyzed. Two controls were included in each run of the test samples. All the samples were tested and patterns analyzed by blinded technical staff. Apparently, the method is reproducible. This is indicated by the RAPD patterns of the two controls of between run assay. Interestingly, some RAPD patterns were more prevalent in the clinical isolates than the environmental specimens and vice versa. For example, Q162KKU4-0 and Q162KKU1-0 were found 3. 5 and 3.3 times more often in the clinical specimens (P<0.025). Likewise, Q162KKU1-1 and Q162KKU4-1 were found 18 and 37 times more often in the environment (P<0.0000001). In addition, there was a bias in the distribution of arabinose positive strains and particular RAPD patterns; RAPD patterns of B. pseudomallei that were found frequently in septicemic patients were less likely to be arabinose positive. The data suggest the existence of bacterial genetic differences between the clinical and environmental isolates of B. pseudomallei. Further analysis of the RAPD patterns searching for common polymorphic DNA fragments and systemic comparative genomic analysis of B. pseudomallei in accordance with the clinical data should reveal genetic factors involved in severity and bacterial pathogenesis of B. pseudomallei in melioidosis.

Epidemiology of Burkholderia pseudomallei in Thailand.

The distribution of Burkholderia pseudomallei in soil collected from four regions of Thailand and the frequency of B. pseudomallei infections in patients attending government hospitals throughout Thailand in 1997 were surveyed. A total of 3,585 soil samples collected from 896 sites in four regions of Thailand were cultured for B. pseudomallei using selective enrichment broth and modified Ashdown's agar. The organism was recovered in 4.4%, 6.1%, 20.4%, and 5.9% of the soil samples collected from the northern, central, northeastern, and southern regions, respectively, of Thailand (P < 0.0001). Burkholderia pseudomallei was cultured from 50.1% of the sites in the northeastern region compared with 13.8%, 24.5%, and 18.4% in the northern, central, and southern regions, respectively (P < 0.0001). The infection rate in patients attending government hospitals in the northeastern region (137.9 per 100,000 inpatients) was significantly higher than those in the northern (18 per 100,000 inpatients), central (13.4 per 100,000 inpatients), and southern (14.4 per 100,000 inpatients) regions, respectively (P < 0.0001). It is suggested that melioidosis, which is endemic in Thailand, is associated with the presence of B. pseudomallei in soil.

Epidemiology of arabinose assimilation in burkholderia pseudomallei isolated from patients and soil in Thailand.

Burkholderia pseudomallei is an environmental saprophyte that has been isolated widely from soil in Southeast Asia and the relationship between environmental contamination and clinical melioidosis has been established. It has been shown that the arabinose assimilation property of B. pseudonrallei is probably one of the determinants indicating virulence of this organism. Therefore, the distribution of arabinose assimilation biotypes of B. pseudomallei collected from four geographic regions of Thailand was studied in order to determine an association between arabinose assimilation of B. pseudomallei and the uneven distribution of melioidosis found among these four areas. A total of 830 isolates of B. pseudomallei (412 patient isolates and 418 soil isolates) collected from the patients and soil in four regions of Thailand in 1997 were tested for an ability to grow on a minimal agar medium supplemented with L-arabinose. All patient isolates except one could not utilise arabinose (Ara-). For 418 soil isolates, 232 (55.5%) isolates were identified as Ara type. They comprised 180 (62.5%), 36 (46.8%), 6 (35.3%) and 10 (27.8%) isolates derived from northeastern, southern, northern and central regions respectively. The ratios of Ara- to Ara, were 1.7, 0.9. 0.5 and 0.4 among isolates collected from northeastern, southern, northern and central regions respectively. The prevalence of Ara- in soil isolates in northeast is significantly higher than those in other regions. This observation suggests that in addition to the presence of B. pseudomallei in soil which is one of the factors contributing to a burden of melioidosis in northeastern Thailand, the distribution of more virulent biotype (Ara-) soil isolates is a factor contributing to a high prevalence of melioidosis in northeastern Thailand as well.

Impact of an educational program on antibiotic use in a tertiary care hospital in a developing country.

A multi-cross-sectional study was conducted in a 2000-bed tertiary care university hospital in Bangkok, Thailand, from September 1993 to May 1994 to assess the effectiveness of an educational program on the use of antibiotics. Data on the study covered antibiotic usage both in-patients and out-patients. Data were collected for a 24-hour period every 2 weeks for 7 days for each 3-month period. The target population were residents, general practitioners, and sixth-year medical students. The educational program provided information derived from the data of inappropriate use of antibiotics during the pre-intervention period and guidelines on the use of antibiotics which were agreed to by a consensus among the faculty in all clinical departments. The study revealed: (1) the prevalence of antibiotic use and the cost of antibiotics during post-intervention period was significantly decreased by 20%; (2) the use of antibiotic prophylaxis for obstetrics patients and patients undergoing cataract surgery decreased significantly; (3) there was a shift from second or third generation cephalosporins to cefazolin for surgical prophylaxis; (4) the duration of perioperative antibiotic prophylaxis was reduced to under 2 days; (5) there was a shift from netilmicin or amikacin to gentamicin for the treatment of community acquired infection; and (6) the mortality, median length of hospital stay, and nosocomial infection rate among the patients who received antibiotics during the post-intervention period were not significantly different from those during the pre-intervention period. These results suggest that this educational program comprising information feedback and antibiotic usage guidelines was effective in improving antibiotic use at this tertiary care university hospital in Thailand.

Universal precautions: costs for protective equipment.

BACKGROUND: The amount and costs of protective equipment used to implement universal precautions in Thailand have not previously been studied. METHODS: A cross-sectional study was done to determine the frequency of clinical and laboratory procedures requiring universal precautions and the amount of protective equipment needed for each. RESULTS: The study was performed in 24 government hospitals in Thailand in December 1993. Totaling 6549 beds, these hospitals had provided service to 357,391 inpatients and 3,411,122 outpatients during the previous year. The annual number of procedures performed in these hospitals was estimated at 17.5 million, with expenditures for protective equipment of $2.4 million (U.S.) per year. The average overall cost for protective equipment was U.S. $5.37 for one inpatient stay and U.S. $0.15 for one outpatient visit. The projected national expense for these barriers was U.S. $41.5 million per annum. The cost for these barriers after the implementation of universal precautions was 2.5 times the cost before implementation. CONCLUSIONS: Overuse of sterile and examination gloves and gowns and underuse of heavy-duty gloves, masks, aprons, goggles, and boots were discovered during the study. Appropriate use of disposable and reusable universal precautions equipment would free health care dollars for other purposes.

Non-typhoidal Salmonella bacteraemia: clinical features and risk factors.

A case control study was conducted to determine the risk factors of non-typhoidal Salmonella bacteraemia. Eighty adult patients with non-typhoidal Salmonella bacteraemia admitted to Siriraj Hospital from January to December 1993 served as the cases. The controls comprised 3 groups: group 1, 80 adult in-patients with Escherichia coli bacteraemia; group 2, 80 adult in-patients who did not have bacteraemia and had been admitted to the hospital during the same period as the cases; group 3, 80 in-patients who did not have Salmonella bacteraemia and matched the cases in terms of gender, age, hospital services and admission date. AIDS and corticosteroid use were the major risk factors for acquiring non-typhoidal Salmonella bacteraemia with an odds ratio of 7.27 to 12.31 (95% confidence interval of 3.39 to 29.40). Almost all patients with non-typhoidal Salmonella bacteraemia presented with a fever for a median duration of 7 days. AIDS patients usually had concomitant opportunistic infections. Salmonella group D was the most common serogroup. Most patients were treated with co-trimoxazole, quinolones, ceftriaxone and ampicillin. Localized suppurative complications were observed in 14% of the patients; the overall mortality rate was 36.3%, 12% of whom died prior to receiving appropriate antibiotics for Salmonella.