Immune responses of selected phagotopes from monoclonal antibodies of Burkholderia pseudomallei.

Random peptide libraries displayed by bacteriophage T7 and M13 were employed to identify mimotopes from 4 monoclonal antibodies (MAbs) specific to Burkholderia pseudomallei. Insert DNA sequences of bound phages selected from four rounds of panning with each MAb revealed peptide sequences corresponding to B. pseudomallei K96243 hypothetical protein BPSL2046, hypothetical protein BpseP_02000035, B. pseudomallei K96243 hypothetical protein BPSS0784, B. pseudomallei 1710b hypothetical protein BURPS1710b_1104, and B. cenocepacia H12424 TonB-dependent siderophore receptor, all located at the outer membrane. The immune responses from all selected phagotopes were significantly higher than that of lipopolysaccharide. The study demonstrates the feasibility of identifying mimotopes through screening of phage-displayed random peptide libraries with B. pseudomallei MAbs.

Safety and efficacy of hyptis suaveolens extract for therapy of influenza in healthy adults.

Objective: To determine the safety and efficacy of H.suaveolens extract for therapy of influenza in healthy adults. Methods: The study was randomized double blind placebo controlled study conducted in 15 community and general hospitals from May to August 2006. The study subjects were healthy adults who had influenza-like symptoms and positive preliminary diagnostic test for influenza A or B from respiratory secretions. They were randomized to receive H.suaveolens extract 500 mg 3 times daily or the placebo 3 times daily for 7 days. The subjects were evaluated for the severity of symptoms related to influenza, adverse effects of the medications and the presence of influenza viruses from respiratory secretions at entry, day 4 and day 7 after treatment. Results: There were 39 subjects in the placebo group and 46 in the H.suaveolens group. There was a significant improvement in symptoms of the patients in both groups on day 4 and day 7 when compared with that at entry. However, the average duration of fever of the patients in both groups was not significantly different (3.1 days in the placebo group vs. 3 days in the H.suaveolens group, p=0.749). The recovery rates of influenza A and influenza B viruses from respiratory secretions of the subjects on day 4 and day 7 after treatment in both groups were not significantly different. A trend of less positive culture for influenza A virus in the patients receiving H.suaveolens extract (32.5%) compared with those receiving a placebo (47.1%) was observed. The compliance to medications was satisfactory. No serious adverse effects due to study medications were observed. Conclusion: H.suaveolens extract 1.5 grams per day for 7 days is safe but it is not effective in relieving influenza-related symptoms in adults with influenza. The lack of efficacy of H.suaveolens extract might be due to an insufficient dosage of the extract.

In vitro activity of ceftobiprole against hospital-acquired bacteria commonly causing infections in hospitalized patients at Siriraj Hospital.

Objective: To determine the in vitro activity of ceftobiprole against resistant bacteria commonly causing infections in hospitalized patients at Siriraj Hospital. Methods: The studied organisms were MRSA (32 isolates), Enterococcus sp. (30 isolates), ESBL-producing E.coli (20 isolates), ESBL-producing K.pneumoniae (20 isolates), MDR P.aeruginosa (30 isolates) and MDR A.baumannii (30 isolates). The susceptibility of ceftobiprole was determined by the disk diffusion test for all 162 isolates and the MIC was determined by the E-test method for 5 isolates of each organism. Results: All isolates of MRSA and 77% of Enterococcus sp. isolates were susceptible to ceftobiprole. All isolates of ESBL-producing E.coli and MDR A.baumannii were not susceptible to ceftobiprole. Only 10% to 20% of ESBL-producing K.pneumoniae and P.aeruginosa were susceptible to ceftobiprole. The MICs of ceftobiprole against all tested organisms were correlated with the inhibition zone diameters. Conclusion: Ceftobiprole is very active against MRSA and is moderately active against Enterococcus sp. Ceftobiprole is considered inactive or less active against ESBL-producing gram negatives, MDR P.aeruginosa and MDR A.baumannii.

Pyridoxine (vitamin B6) usage in tuberculosis patients at Siriraj Hospital.

Objective: To determine the prevalence and factors associated with pyridoxine usage in tuberculosis patients who received isoniazid at Siriraj Hospital. Methods: The medical records of 254 patients with tuberculosis who received isoniazid at Siriraj Hospital during January 2006 to February 2007 were analyzed. Results: Of 254 patients, 132 (52%) were males and the mean age was 44.5 years. The common underlying diseases were HIV infections, diabetes mellitus and cancers. Pulmonary tuberculosis was the most common type of tuberculosis (67.7%). Pyridoxine was given to 213 patients (83.9%) who received isoniazid. Pyridoxine was usually prescribed to the patients with HIV infections or diabetes mellitus. Peripheral neuropathy was observed in a patient who received antituberculous drugs along with pyridoxine, stavudine, lamivudine and nevirapine. His peripheral neuropathy improved after stavudine was switched to zidovudine. Conclusion: Pyridoxine is usually given to tuberculosis patients who receive isoniazid despite of lacking any solid evidence on effectiveness of pyridoxine in preventing peripheral neuropathy.

Prevalence of antibiotic-resistant bacteria colonized in neutropenic patients at Siriraj Hospital.

Objective: To determine prevalence of antibiotic-resistant bacteria colonized in throat and gastrointestinal tract of neutropenic patients at Siriraj Hospital. Methods: Adult patients who had recent neutropenia (absolute neutrophils <500) without any evidence of infections were recruited from January 2006 to March 2007 at Hematology Clinic and Department of Medicine, Siriraj Hospital. The throat swabs and stool samples or peri-anal swabs collected from the patients were sent for bacterial culture and antibiotic susceptibility testing. Results: There were 140 patients. 75 (53.6%) were females. The mean age was 49.3 years. The major underlying diseases were leukemia (53.6%) and lymphoma (33.3%). The main causes of neutropenia were chemotherapy-induced (84.3%) and the underlying diseases (15.7%). The bacteria commonly recovered from the stools or throat swabs of the patients were E.coli (77.9%), Klebsiella pneumoniae (46.4%), Enterobacter sp (20%) and Enterococcus sp. (45.7%). ESBL-producing gram negatives, Pseudomonas aeruginosa, Acinetobacter sp. and MRSA were found in 13.6%, 8.6%, 5% and 1.4% respectively. The susceptibility rate of E.coli, Klebsiella pneumoniae and Enterobacter sp. to co-trimoxazole, co-amoxiclav and ciprofloxacin was 51.5%, 73.2% and 74.8% respectively. Less than 50% of ESBL-producing gram negatives, Pseudomonas aeruginosa and Acinetobacter sp. were susceptible to the aforementioned oral antibiotics. Conclusion: Ciprofloxacin or co-amoxiclav seems to be a suitable oral antibiotic for preventing gram negative bacterial infection in ambulatory neutropenic patients in Thailand. However, the patients receiving such antibiotics still have more than 25% risk of carrying gram negatives resistant to both antibiotics.

Development of appropriate procedures for inflation of endotracheal tube cuff in intubated patients.

BACKGROUND: Hyperinflation of endotracheal tube cuff causes tracheal mucosal damage and underinflation increases the risk of pneumonia. The current practice on inflation of endotracheal tube cuff in the intubated patients hospitalized at Siriraj Hospital uses the estimation method. The authors determined appropriateness of such current practice and developed an appropriate procedure for inflation of endotracheal tube cuff in intubated patients. MATERIAL AND METHOD: The endotracheal tube cuff pressures of 34 intubated patients in Siriraj Hospital were measured by manometer once daily. Inflation of the endotracheal tube cuffs of 20 patients was done and the volume of air required to optimize the intracuff pressure of 25 cmH2O was recorded. The intracuff pressure was measured every one hour for eight consecutive hours in the patients who had initial intracuff pressure of 25 cmH2O and 30 cmH2O. The nurses in the experimental wards used a manometer as a guide to inflate endotracheal tube cuff until the intracuff pressure was 30 cmH2O every eight hours, whereas the control wards used conventional procedures to inflate the endotracheal tube cuff. The endotracheal tube cuff pressures of the patients in both groups were measured twice daily. RESULTS: Only 34% of intracuff pressure measurements were 20-30 cmH2O. The mean volume of inflated air required to achieve an intracuff pressure of 25 cmH2O was 7.1 ml. An initial intracuff pressure of 30 cmH2O decreased to 20 cmH2O at 7 to 9 hours after inflation. The rate of optimum endotracheal tube cuff pressure was 90.5% in the group guided by manometer and 31.8% in the conventional procedure group (p < 0.001, RR 2.85, 95% CI 2.44-3.32). CONCLUSION: Inflation of endotracheal tube cuff should be guided by manometer to achieve a pressure of 30 cmH2O every eight hours.

Stenotrophomonas maltophilia infections in hospitalized patients at Siriraj Hospital.

Ninety-seven strains of Stenotrophomonas maltophilia isolated from 62 patients hospitalized at Siriraj Hospital from September 2005 to February 2006 were studied. Ninety-two strains (94.8%) were isolated from respiratory secretions and five strains (5.2%) were from blood. Only 39.3% of the patients who had S. maltophilia isolated from their clinical specimens had infections. All S. maltophilia infections were hospital acquired and the infected patients had underlying diseases, multiple medical devices and received multiple antibiotics prior to S. maltophilia infections. Pneumonia was the most common site of infections. S. maltophilia was susceptible to co-trimoxazole in 68.8% of the isolates. The overall mortality of the patients with S. maltophilia infections was 45.5%.

Efficacy and safety of cinnamon stomachic mixture for patients with functional dyspepsia.

Health care personnel at a community hospital have used cinnamon stomachic mixture for treatment of patients with functional dyspepsia for many years and they claimed that cinnamon stomachic mixture was effective without any supportive evidence. Objective: To determine the efficacy, safety, patients’ compliance and satisfaction with the treatment of cinnamon stomachic mixture. Methods: This was a randomized controlled study in 318 adults with functional dyspepsia presenting to 6 community hospitals. The patients were randomized to receive 105 mg of simethicone three times a day or 30 ml of cinnamon stomachic mixture three times a day for 7 to 14 days. The patients were evaluated for improvement of symptoms, compliance to medication and patients’ satisfaction with the treatment. The data were analysed by descriptive statistics, chi-square statistics, student t test, analysis of variance and non-parametric tests where appropriate. Results: One hundred and fifty patients received simethicone and 168 patients received cinnamon stomachic mixture. The baseline characteristics of the patients in both groups were not significantly different. The patients’ compliance to simethicone and cinnamon stomachic mixture was 82% and 89.3% respectively (p=0.09). The severity of the symptoms after treatment and the response rates were not significantly different between both groups. Side effects were observed in 9.3% and 9.5% in the simethicone group and the cinnamon stomachic mixture group respectively. Most of the patients in both groups were satisfied with the treatments they received. The cost of a 14-day course of cinnamon stomachic mixture was 36 baht compared with 84 baht for that of simethicone. Conclusion: Cinnamon stomachic mixture is effective and safe for the treatment of the patients with functional dyspepsia similar to simethicone.

Epidemiology of Staphylococcus aureus infections and the prevalence of infection caused by community-acquired methicillin-resistant Staphylococcus aureus in hospitalized patients at Siriraj Hospital.

BACKGROUND: The CA-MRSA infections have emerged in many parts of the world over the past decade. To our knowledge, the prevalence of CA-MRSA infections in Thai patients is unknown. OBJECTIVE: To determine an epidemiology of Staphylococcus aureus (S. aureus) infections in hospitalized patients in Siriraj Hospital and the prevalence of infections caused by community-acquired methicillin-resistant S. aureus (CA-MRSA). MATERIAL AND METHOD: The study was carried out at Siriraj Hospital from January to May 2005. The eligible patients were hospitalized patients whom S. aureus were isolated from their clinical specimens submitted to Department of Microbiology. S. aureus isolate was classified into infection or colonization. S. aureus infections were further classified into methicillin-resistant S. aureus (MRSA) or methicillin-sensitive S. aureus (MSSA) infections, and hospital-acquired (HA) or community-acquired (CA) infections. CA-MRSA infection is defined as infection caused by MRSA isolated from the patient within 72-hour of hospitalization and has no features of HA MRSA infections. RESULTS: There were 669 S. aureus isolates from 448 patients. Two hundred and sixty two patients (58.5%) were MSSA whereas 186 (41.5%) were MRSA infections. CA-MRSA was found in three isolates (0.9% of total MRSA) from two patients. CONCLUSION: The prevalence of CA-MRSA infections in hospitalized patients in Siriraj Hospital was uncommon and these patients could probably be HA MRSA infections.

Cost-effectiveness analysis of chlorhexidine gluconate compared with povidone-iodine solution for catheter-site care in Siriraj Hospital, Thailand.

BACKGROUND: Catheter-related bloodstream infections (CRBSI) are an important cause of patient morbidity, mortality, and increased health care costs. Use of an antiseptic solution for skin disinfection at the catheter insertion site helps prevent catheter-related infections. In Thailand, povidone-iodine solution is the most commonly used agent for this purpose. However, the results of several studies including a meta-analysis indicated that the use of chlorhexidine gluconate is more effective than the use of povidone-iodine as an antiseptic for preventing CRBSI. This study evaluated the cost-effectiveness of chlorhexidine gluconate versus povidone-iodine for catheter-site care using the Siriraj Hospital perspective. MATERIAL AND METHOD: We used a decision analytic modeling for estimating the cost-effectiveness of antiseptic solutions. The CRBSI rate was obtained from the Center for Nosocomial Infection Control at Siriraj Hospital, while the efficacy of cholorhexidine compared to povidone-idone was based on a meta-analysis. The cost of managing infections was derived from the Thai Drug Related Group (DRG). A series of sensitivity analyses were performed. Since the time horizon of the analysis was less than 1 year, there was no need for discounting. RESULTS: We found that the use of chlorhexidine, rather than povidone iodine, for central catheter site care resulted in a 1.61% decrease in the incidence of CRBSI, a 0.32 % decrease in the incidence of death, and savings of 304 baht per catheter used. For peripheral catheter site care, the results were similar although the differences were smaller. CONCLUSION: Use of chlorhexidine gluconate in place of the current standard solution for vascular catheter site care is a cost-effective method of improving patient safety in Siriraj Hospital.

In vitro activity of tigecycline against clinical isolates of multidrug-resistant Acinetobacter baumannii in Siriraj Hospital, Thailand.

In vitro activity of tigecycline against 148 strains of Acinetobacter baumannii isolated from different patients hospitalized at Siriraj Hospital, Bangkok, Thailand during 2002 to 2005 was conducted. These isolates were resistant to beta-lactams, aminoglycosides and fluoroquinolones. In vitro susceptibilities were determined by Kirby-Bauer disk diffusion, E-test and broth microdilution methods. The MIC50 and MIC90 values of tigecycline against A. baumannii determined by the broth microdilution method were 0.5 and 1 mg/L respectively. The MICs of tigecycline determined by E-test were 4-fold higher than those from the broth microdilution method. An inhibition zone of > or = 13 mm was well correlated with a tigecycline MIC of < or = 2 mg/L and had a sensitivity of 99% and a specificity of 100%. The study results indicated that 97.3% of MDR A. baumannii strains isolated from the patients hospitalized at Siriraj Hospital were susceptible to tigecycline. Tigecycline may prove to be an important antibiotic for treatment of multidrug-resistant A. baumannii infections in Thailand in the near future.

Implementation of clinical practice policy on the continuous intravenous administration of amphotericin B deoxycholate.

BACKGROUND: Systemic fungal infections have significantly increased. The mainstay of treatment is amphotericin B deoxycholate. A limitation of using amphotericin B includes infusion-related reactions and nephrotoxicity. A continuous infusion of amphotericin B was found to reduce nephrotoxicity and infusion-related reactions. OBJECTIVE: To implement clinical practice policy on the continuous intravenous administration of amphotericin B in the patients hospitalized in general medical wards at Siriraj Hospital. METHOD: A one-page evidence-based clinical practice policy on continuous intravenous administration of amphotericin B was prepared and disseminated to all general medical wards in Siriraj Hospital. The information on the patients who received amphotericin B treatment between March 2004 and March 2006 was collected. The data were analyzed using descriptive statistics, univariate analysis and multivariate analysis as appropriate. A p-value of < 0. 05 was considered statistically significant. RESULTS: Of 166 courses of amphotericin B treatment in 148 patients, 102 courses (61.4%) were given continuous intravenous administration of amphotericin B (CI group) and 64 courses (38.6%) were given conventional 4-to 6-hour intravenous administration (RI group). The mean age of the patients in the CI group was significantly greater than that in the RI group. The CI group had more patients with neutropenia with persistent fever whereas the RI group had more patients with HIV/AIDS and cryptococcal meningitis. The incidence of amphotericin B-related nephrotoxicity was 27.5% in the CI group compared with 39.1% in the RI group (p = 0.164). Chills were observed in 6.9% of the patients in the CI group compared with 26.6% in the RI group (p = 0. 001). Overall mortality at the end of therapy was significantly higher in the CI group. However, most of the deaths in the CI group were unrelated to fungal infections or amphotericin administration. CONCLUSION: Continuous infusion of amphotericin B was associated with a decrease in infusion-related reactions and tended to have less nephrotoxicity than those in the 4-to 6-hour infusion group.

Utilization of calculated low density lipoprotein cholesterol and measured low density lipoprotein cholesterol in Siriraj Hospital.

A study to determine the utilization of calculated low density lipoprotein (c-LDL) cholesterol and measured low density lipoprotein (m-LDL) cholesterol was conducted. The test results of total cholesterol, triglyceride, HDL-cholesterol and m-LDL-cholesterol from the same individuals aged > or = 18 years who had the tests done at the Department of Clinical Pathology, Faculty of Medicine Siriraj Hospital during January to December 2004 were retrieved. The c-LDL-cholesterol level was computed using Friedewald formula. There were two data sets i.e. the m-LDL-cholesterol cut-off level derivation data set (784 subjects) and the m-LDL-cholesterol cut-off level validation data set (800 subjects). The study results revealed: 1) 2.6% of the subjects had blood triglyceride > 400 mg/dl hence c-LDL-cholesterol could not be computed, 2) the correlation between c-LDL-cholesterol levels and m-LDL-cholesterol levels from both data sets was very good (r > 0. 95, p < 0. 001), 3) the m-LDL-cholesterol levels were usually higher than c-LDL-cholesterol levels, 4) the m-LDL-cholesterol cut-off level derivation data set showed that m-LDL-cholesterol < 87, > 143, > 188, > 233 and > 254 mg/dl were highly correlated with c-LDL-cholesterol < 100, > or = 100, > or = 130, > or = 160 and > or = 190 mg/dl respectively, 5) an application of m-LDL-cholesterol cut-off levels derived from the m-LDL-cholesterol cut-off level derivation data set to the m-LDL-cholesterol cut-off level validation data set showed that m-LDL-cholesterol < 87, > 143, > 188, > 233 and > 254 mg/dl had accuracy in predicting c-LDL-cholesterol < 100, > or = 100, > or = 130, > or = 160 and > or = 190 mg/dl of 100%, 99. 7%, 100%, 100% and 100% respectively, 6) the use of m-LDL-cholesterol levels as a guide for initiating lipid-lowering agents based on cut-off values of c-LDL-cholesterol levels led to an overuse of lipid-lowering agents in 3.6% to 42.9% of the patients and 7) Nomogram for transforming m-LDL-cholesterol to c-LDL-cholesterol was developed as well as a formula for transforming m-LDL-cholesterol to c-LDL-cholesterol (c-LDL-cholesterol = 0.89 x m-LDL-cholesterol). Therefore, m-LDL-cholesterol assay has a very limited use in managing individuals with suspected or known dyslipidemia. The use of m-LDL-cholesterol level as a guide for management of abnormal LDL-cholesterol conditions leads to an overuse of lipid lowering medications and an enormous expense of m-LDL-cholesterol assay.

Vancomycin overuse in Siriraj Hospital.

OBJECTIVE: An emergence of vancomycin resistant organisms particularly vancomycin-resistant enterococci (VRE) has become a serious public health concern. To prevent and control the spread of vancomycin resistant organisms, the prudent use of vancomycin is strongly recommended by the Hospital Infection Control Practices Advisory Committee (HICPAC). MATERIAL AND METHOD: A 6-week prospective observational study of vancomycin use was conducted in hospitalized patients at Siriraj Hospital from February to March 2005. Indications of initiating and continuing vancomycin were categorized according to HICPAC recommendations. Factors related to the appropriateness of vancomycin use were also evaluated. RESULTS: At initiation, vancomycin was inappropriately and empirically prescribed 19/222 times (8.6%) and 166/222 times (74.8%), respectively. After microbiological results were obtained, the rate of inappropriate prescription continued 132/222 times (59.5%). Furthermore, inappropriate use was significantly correlated with the type of department. There was a higher rate in the Department of Pediatrics, Surgery and Ophthalmology when compared with that of the Department of Medicine (p = 0.001). The inappropriate use also correlated with topical use (p < 0.001), intravenous administration (p = 0.012) and no consultation with an infectious disease specialist (p = 0.001). The overuse did not improve the clinical outcome. CONCLUSION: A substantial rate of inappropriate use of vancomycin was found in Siriraj Hospital. Intervention to improve appropriateness of vancomycin use should be urgently implemented to prevent and control the emergence of vancomycin resistant organisms.

Clinical study of morus alba linn. on glycemic control and blood lipids in patients with type 2 diabetes: A preliminary study.

Effects of Morus alba-leaf extracts on glycemic control and blood lipids were carried out in 27 patients with newly diagnosed type 2 diabetes. Water extracts of Morus alba leaves at a dosage of 700 mg were given to the patients thrice daily for 8 weeks. The patients did not receive any concomitant medications for diabetes or hyperlipidemia. The mean fasting plasma glucose levels at baseline, week 2, week 4, week 6 and week 8 were 155.1, 179, 173.6, 183.9 and 185.8 mg/dl, respectively (p=0.04). The mean glycosylated hemoglobin levels at baseline and week 8 were 7.6% and 8.4%, respectively (p=0.002). The mean blood total cholesterol levels at baseline, week 2, week 4, week 6 and week 8 were 229.6, 211.2, 210.2, 204.5 and 199.4 mg/dl, respectively (p<0.001). The mean blood triglyceride levels at baseline, week 2, week 4, week 6 and week 8 were 235.4, 191.3, 174.5, 183.5 and 168.2 mg/dl, respectively (p=0.001). No patients experienced side effects of the treatment. Laboratory results on CBC, urine, blood electrolytes, renal function and liver function at baseline, week 2, week 4, week 6 and week 8 were not significantly different. Morus alba-leaf extracts have no hypoglycemic effect but they exert lipid lowering effects.

Colonization of nosocomial pathogens on computer keyboards in patient care areas.

Objective: Nosocomial infections are an important cause of morbidity and mortality in hospitalized patients. The role of the hospital environment as a reservoir of nosocomial pathogens is controversial and has not been thoroughly investigated. In the past years at our institution, computers have been widely used in patient care areas, including general wards and intensive care units. There are studies which show that inanimate objects in the hospital environment constitute reservoirs of nosocomial pathogens. Hence, the study is designed to determine whether computer keyboards in the patient care areas in the Department of Medicine, Siriraj Hospital were reservoirs of nosocomial pathogens. Methods: Twenty-six computer keyboards from general medical wards (20) and intensive care units (6) and 26 computer keyboards from secretarial offices were studied from August to September 2003. All the keyboards were cultured for aerobic pathogens by cotton swab technique. Results: The overall colonization rate of pathogens on the keyboards was 96.2% from patient care areas and 92.3% from the offices (p=1). The colonization rates of non-fermentative gram negative bacilli on the keyboards located in the patient care areas and the offices were 11.5% and 0%, respectively (p=0.24). However, if the fungal isolate was considered a potential pathogen, its colonization rate on the keyboard was 4.3% in the patient care areas compared with 1.5 % in the offices (p=0.03). Conclusion: There was a trend in finding potential pathogenic organisms more often from the computer keyboards located in the patient care areas than from those in the offices. The computer keyboards located in the patient care areas should be periodically cleaned.

Epidemiology of acinetobacter baumannii infections in Siriraj Hospital 2002.

A.baumannii is a pathogen causing hospital-acquired infections. A.baumanii infections are difficult to treat because this organism is usually multi-drug resistant. Objective: To determine the epidemiology of A. baumannii infections in Siriraj Hospital in 2002. Methods: From January to December 2002, we prospectively studied hospitalized patients in Siriraj Hospital who had A.baumannii isolated from their clinical specimens. Results: During the study period, A.baumannii was isolated from clinical specimens of 208 cases. Eighty-six patients (41.3%) had A. baumannii infections whereas 122 patients (58.7%) had A. baumannii colonization. Of the 86 patients with A.baumannii infections, 54.7% were males and 45.3% were females. The mean age of patients was 56.1 years. Ninety-eight percent of the infections were hospital-acquired. The patients developed infection after an average of 26 days of hospitalization. Fifty-two percent of the patients were in the general wards, whereas 48% of them were in ICU. The common sites of infection were respiratory tract and skin and soft tissues. Factors associated with A.baumannii infection were identified in 98.8% of the patients. The most common factors were prior use of antibiotics especially ceftazidime and indwelling medical devices. The susceptibility of A.baumannii to carbapenems, aminoglycosides, beta-lactam/ beta-lactamase inhibitors, co-trimoxazole, fluoroquinolone, 4th generation cephalosporins and 3rd generation cephalosporins was 32%, 16%, 12 %, 9%, 7%, 4% and 3%, respectively. Fifty-seven percent of A.baumannii isolates were resistant to all antimicrobials currently available in Thailand. The overall mortality rate of the patients infected with A.baumannii was 54.7%. Conclusion: Most A.baumannii infections in Siriraj were hospital-acquired. The most common site of infection was the respiratory tract. The majority of A.baumannii isolates was multi-drug resistant. The mortality rate of A.baumannii infections was high.