Prevalence of extended-spectrum beta-lactamase and class 1 integron integrase gene intl1 in Escherichia coli from Thai patients and healthy adults.

Among 120 Escherichia coli isolates from Thai patients, 37 and 9 isolates were extended-spectrum beta-lactamase (ESBL) and suspected ESBL producers respectively while 5 E. coli isolates from 120 Thai healthy adults were suspected ESBL producers. Integrase (intl1) gene was detected in 99% of the clinical and 87% of the non-clinical isolates. Among 37 ESBL producers, percent recovery of bla(TEM), bla(CTX-M), bla(SHV) and bla(VEB) was 78%, 78%, 8% and 8%, respectively. Twenty-five isolates of ESBL producers carried both bla(TEM) and bla(CTX-M), 2 isolates carried 3 genes (bla(TEM), blac(CTX-M), and bla(SHV)) and 3 showed no detectable bla gene. Among the 14 suspected ESBL producers, intl1 and bla(TEM) were detected in 13 isolates. ESBL producers from clinical samples were resistant to most of the tested antimicrobial agents compared to non-ESBL producers and isolates from healthy adults with about half of the latter susceptible to all tested antimicrobial agents. Only one clinical isolate was resistant to imipenem. Susceptibility to trimethoprim/sulfamethoxazole among the clinical isolates in ESBL producer group (27%) and non-producer group (33%) were comparable, whereas the percent susceptibility of the non-clinical isolates was about twice that of the clinical isolates.

Antimicrobial susceptibility of Streptococcus pneumoniae isolated from patients with respiratory tract infections in Thailand.

A total of 400 clinical Streptococcus pneumoniae strains from patients with respiratory diseases were collected from January 2002 to December 2005. In this study, an increased prevalence of penicillin-nonsusceptible S. pneumoniae (PNSP) from 63% in 2002-2003 to 69% in 2004-2005 was found. During 2004-2005, 56% were erythromycin-nonsusceptible S. pneumoniae (ENSP) and 54% were both PNSP and ENSP. The PNSP, ENSP and PNSP+ENSP groups showed similar trends, ie, sensitive to amoxicillin/clavulanate (range 97.2-98.5%), levofloxacin (range 90.7-92.4%), ceftriaxone (range 87.1-89.4%), and ofloxacin (range 64.8-66.1%). Lower levels of susceptibility were detected for azithromycin, clarithromycin, cefdinir, cefprozil, clindamycin, co-trimoxazole, chloramphenicol and tetracycline in penicillin and erythromycin-nonsusceptible strains. Of the macrolide-resistant S. pneumoniae, 55% of strains exhibited the M phenotype and 45% the constitutive MLS(B) phenotype. No pneumococci with the inducible MLS(B) phenotype were detected in Thailand.

Preliminary study of randomly-amplified polymorphic DNA analysis for typing extended-spectrum beta-lactamase (ESBL)-producing Klebsiella pneumoniae.

Objective: Extended-spectrum beta-lactamases (ESBLs) are most prevalent in Klebsiella pneumoniae. This organism is frequently isolated from clinical specimens and can cause septicemia, pneumonia or urinary tract infection. There were occasionally suspicious outbreaks of ESBL-producing K. pneumoniae in patients' wards. The objective is to determine whether the randomly amplified polymorphic DNA (RAPD), which is a polymerase chain reaction (PCR)-based typing technique, can be used as a typing method for studying the molecular epidemiology of ESBL-producing K. pneumoniae. MATERIAL AND METHOD: The present study was carried out by using 30 ESBL-producing K. pneumoniae isolates obtained from different patients admitted to Siriraj Hospital between January and February 2004. RAPD was evaluated for three primers. All isolates were re-examined by using Southern blot hybridization. RESULTS: It was found that 29 DNA band patterns were generated individually by either AP4 or HLWL74 and R108 primers (30 patterns) for RAPD analysis and 30 patterns for Southern blot hybridization with class 1 integron (intI1) probe. Different patterns indicated that these 30 isolates could not be the cause of an outbreak in Siriraj Hospital. CONCLUSION: The RAPD typing is good and can be used as a screening, rapid and inexpensive'test for ESBL-producing K. pneumoniae during investigation of outbreaks.

Bartonella henselae: first reported isolate in a human in Thailand.

This is the first reported case of bacillary angiomatosis associated with Bartonella henselae in Thailand. The clinical, pathological, and microbiological findings are presented. The bacterium was isolated from a biopsy of skin lesions obtained on admission and identified by cellular morphology, characteristics of colonies on chocolate agar, extensive biochemical tests and 16S ribosomal DNA sequencing.

Roseomonas gilardii subsp rosea, a pink bacterium associated with bacteremia: the first case in Thailand.

Roseomonas is a pink-pigmented, non-fermentative, gram-negative coccobacillus bacterium. Human infections caused by Roseomonas are very rare. We report the first case of bacteremia associated with Roseomonas gilardii subsp rosea in Thailand. The bacterium was isolated from blood culture and identified by cellular morphology, characteristics of colonies on blood agar, extensive biochemical tests and 16S ribosomal DNA sequencing.

Five-year study of antimicrobial susceptibility and beta-lactamase production in Haemophilus influenzae.

We evaluated 582 Haemophilus influenzae isolates from patients between January 2000 and December 2004. Overall, 433 isolates were obtained from sputum and bronchial washings, 124 isolates were from pus, 19 isolates were from blood and 6 isolates form cerebrospinal fluid. H. influenzae was sensitive to amoxicillin/clavulanate, ampicillin/sulbactam, gentamicin, cefuroxime, ceftriaxone, cefotaxime, ciprofloxacin, ofloxacin, imipenem, meropenem (range 97-100%), chloramphenicol (75%), ampicillin/amoxicillin (52%), but resistant to trimethoprim-sulphamethoxazole. As for beta-lactamase production, 48.4% of the isolates tested were positive.

Serotypes and antimicrobial susceptibilities of Streptococcus pneumoniae isolated from hospitalized patients in Thailand.

Two hundred seven Streptococcus pneumoniae isolates were obtained from patients admitted to Siriraj Hospital. One hundred two, and 105 isolates were from sterile sites and non-sterile sites, respectively. They were serotyped by Quellung reaction with specific antisera from Statens Serum Institut; 81.6% of these pneumococci were typeable. These serotypes were included in the 23-valent pneumococcal polysaccharide vaccine. The five most common serotypes were serotype 6 (22.5%), followed by serotype 23 (18.9%), serotype 19 (16.6%), serotype 3 (7.7%) and serotype 11 (5.3%). Among typeable pneumococci (169 isolates), 52.7% were from sterile sites and 47.3% were from non-sterile sites. Serotypes 6, 23 and 19 were the predominant serotypes isolated from sterile sites. Of the 9 drugs tested, pneumococcal isolates were sensitive to ofloxacin (99%), ciprofloxacin (81.5%), meropenem (80%), imipenem (66.5%), ceftriaxone (65%), cefotaxime (63%), erythromycin (58%), penicillin (48%), and trimethoprim-sulfamethoxazole (34.5%).

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.

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.

Discriminatory powers of molecular typing techniques for methicillin-resistant Staphylococcus aureus in a university hospital, Thailand.

Discriminatory powers of various molecular techniques were evaluated for typing of methicillin-resistant Staphylococcus aureus (MRSA) isolated in Siriraj Hospital, Bangkok, Thailand. Thirty MRSA isolates were randomly selected in this study. They were characterized by pulsed-field gel electrophoresis, Clal-mecA and Clal-Tn554 polymorphisms, ribotyping, and PCR-based methods including SCCmec typing, spa and coa gene polymorphism, and repeat units in hypervariable region downstream of mecA. Individual molecular typing technique distinguished those MRSA isolates into 2 to 5 types. Eleven genetic backgrounds of MRSA isolates were elucidated by combination of typing methods with trimethoprim/sulfamethoxazole (TMP/SXT) susceptibility. Combination of all typing methods including TMP/SXT susceptibility yielded a discriminatory index of 0.94. Combination of PCR-based methods and TMP/SXT susceptibility, with the discriminatory index of 0.89, is a practical typing approach suitable for rapid epidemiological investigation of MRSA isolates in a hospital setting.

Comparison of outcomes and efficiency between drawing two blood samples and three blood samples for culture.

Objective: Since the Department of Microbiology, Faculty of Medicine Siriraj Hospital recommends that three blood samples or at least two blood samples should be sent to the laboratory for culture, the study is designed to determine the outcomes and efficiency between drawing two blood samples and three blood samples for culture. Methods: The results of all blood samples sent to the microbiology laboratory for culture from March 2002 to February 2003 were analyzed. Results: 782 blood cultures had three blood samples, and 10,264 had two blood samples. The overall positive culture rates of the two blood samples and three blood samples were 14.1% and 18.5%, respectively (p<0.001). The positive culture rates for pathogenic organisms of the two blood samples and three blood samples were 10.4% and 15%, respectively (p<0.001). The types of organisms recovered from both groups were similar. Drawing three blood samples was not relatively more efficient due to its higher cost with minimal significant benefit. Conclusion: For general patients suspected of having bacteremia, drawing two blood samples should be sufficient for culture, and it is more efficient than drawing three blood samples.

A study on the application of pasteurization of medical equipment.

OBJECTIVES: To study the need of pasteurization of medical equipment and the possibility of production of pasteurizer in Thailand. MATERIAL AND METHOD: The need of pasteurization of medical equipment was studied by a set of questionnaires to heads of the central sterile supply department (CSSD) and head ward nurses in 29 hospitals across Thailand. Efficacy of pasteurization was demonstrated by disinfection with an imported pasteurizer. A pasteurizer was later produced by the researchers and had it tested for efficacy in disinfection. RESULTS: There were 26 items of medical equipment that could be disinfected by pasteurization. The number of the equipment was 6.2 pieces per bed per week. Disinfection of the equipment was done in C.S.S.D. as well as in patient's wards. The imported pasteurizer was efficacious in disinfection. The pasteurizer made by researchers was convenient for use, not expensive to manufacture and the operating cost for disinfection was 2 to 6 folds less than that done by ethylene oxide gas. CONCLUSION: Pasteurization is effective in disinfection and is applicable to certain heat labile medical equipments. A pasteurizer is not difficult to produce, cheap and the operating cost is low. Pasteurization should be more widely applied in Thailand

Reduction of the incidence of pressure sores by an education program on nursing care.

OBJECTIVES: To determine whether an education and campaign program would reduce the incidence of pressure sores. MATERIAL AND METHOD: The study was performed in a 1,400-bed teaching hospital in Thailand with a total number of 697patients from 47 wards for a point prevalence study; 1,201 and 1,268 patients from 12 wards to determine whether reduction of pressure sore occurrence would be obtained by an education program. RESULTS: The point prevalence of pressure sores was 10.8%. The significant risk factors were age older than 60 years, fecal incontinence, and history of diarrhea. The occurrence of pressure sores was significantly reduced after the educational program from 9.91% to 5. 76%. The education on patient care aiming at reduction of the occurrence of pressure sores could be adopted nation-wide in order to reduce the morbidity, mortality and expenses. CONCLUSION: The education program was effective in reducing the incidence of pressure sores.

Endemic Serratia marcescens in a neonatal intensive care unit.

OBJECTIVE: To study the endemicity of Serratia marcescens in a neonatal intensive care unit (N.I.C.U). MATERIAL AND METHOD: During the first 4 months of 2001, neonates in the N.I.C.U. in a teaching hospital were screened for S. marcescens by serial throat swabs and collections of other appropriate clinical specimens. Environmental cultures were also done in the same period. Isolated S. marcescens were tested for antimicrobial susceptibility and for genotyping by pulsed field gel electrophoresis. RESULTS: During the period, 104 neonates were studied. S. marcescens were isolated in 34.6% of the cases. Environmental cultures were positive for S. marcescens in 1.4%. There were 10 patterns of antibiogram of the 190 strains isolated. All strains belonged to pulsotype A. CONCLUSION: The study confirmed that S. marcescens was endemic in the N.I.C.U. and belonged to one genotype.

Persistence of antimicrobial effect of antiseptics in surgical hand hygiene regimens.

OBJECTIVES: To determine the persistence of antimicrobial effect of antiseptic solutions used in surgical hand hygiene procedure, and the in-house preparation was compared to the commercial solution for its efficacy. MATERIAL AND METHOD: The present study was performed in a 150-bed hospital involving 19 staff from general, orthopedics, KUB, and OB-GYN surgical teams in 48 operations. The antimicrobial effects from 4 different solutions were determined and compared. RESULTS: The study showed that the commercial alcohol-based antiseptic solution was equally or more effective than long-time accepted povidone-iodine or chlorhexidine gluconate solutions and had better persistent effect. The in-house preparation was effective comparable to the commercial solution. CONCLUSION: The commercial alcohol-based antiseptic solution had better persistence of antimicrobial effects compared to the in-house alcohol-based hand rub, povidone iodine and chlorhexidine gluconate.

Cost-effectiveness and safety of reusable tracheal suction tubes.

OBJECTIVES: To evaluate whether the repetitive use of disposable tracheal suction tubes is cost-effective and safe over the single use. MATERIAL AND METHOD: The cost intrinsic to the washing, cleaning, re-sterilization by ethylene oxide gas, and processing was determined and compared to the cost generated by disposable tubes. The reused disposable suction tubes were also determined for their properties in physical characters and probable contamination and damages. RESULTS: The evaluation showed that cost from single-use disposable suction tubes (8.66 baht) was cheaper than expenses generated from processing steps for recycling of disposable tubes (9.92 baht). The use of a disposable tube only once should minimize the risks posed by the use of the potentially unsafe reused disposable tubes both to the patients and health care workers. CONCLUSION: Recycling of tracheal suction tubes was neither cost-effective nor safe.

Effectiveness and microbial contamination of an in-house alcohol-based hand rub.

OBJECTIVES: To evaluate the effectiveness and contamination of an in-house alcohol-based hand rub in a real clinical setting and to compare its effectiveness in bacterial reduction with that of a commercial product. MATERIAL AND METHOD: Effectiveness of the hand rub in bacterial reduction was compared to a commercial product using the modified antiseptic/disinfectant testing method of European Standard (EN 1500) in 12 volunteers. In-house alcohol-based hand rub in 50 clinical wards were serially collected and cultured to determine contamination. RESULTS: The bacterial reduction factor of the hand rub was comparable to that of the commercial product. There was no organisms grown from serial cultures of the in-house alcohol-based hand rub in use for 28 days. CONCLUSION: The in-house alcohol-based hand rub was effective and there was no contamination up to 28 days in use.

Epidemiology of extended-spectrum beta-lactamase producing gram-negative bacilli at Siriraj Hospital, Thailand, 2003.

A cross-sectional study was conducted from August to September, 2003 to determine the prevalence and risk factors in acquiring extended-spectrum beta-lactamase (ESBL) producing gram-negative bacilli (GNB) in patients admitted to Siriraj Hospital and the outcomes of these infections. Of 346 isolates of gram-negative bacteria in 249 patients, 102 isolates from 87 patients were colonization only, but 244 isolates from 162 patients were infections. The common GNB were Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Acinetobacter baumannii and Enterobacter cloacae. The overall prevalence of ESBL producers was 30.1%. K. pneumoniae had a very high prevalence of ESBL producers (56.9%). The urinary tract was the most common site for ESBL- producing GNB infections. Nosocomial infections, duration from admission to infection, peripheral line, urinary catheterization, nasogastric tube insertion and previous use of beta-lactams, cephalosporins and fluoroquinolones were associated with acquiring ESBL-producing GNB infections. ESBL-producing GNB were significantly more resistant to antimicrobial agents. More than 80% of ESBL-producing GNB were susceptible to carbapenems. Mortality in patients infected with ESBL-producing GNB (41.3%) was significantly higher than those infected with non- ESBL-producing GNB (19.8%).

Pneumococci: drug susceptibilities and preliminary epidemiological studies by penicillin binding protein genotyping.

A collection of 307 pneumococcal isolates form 84 children and 223 adults admitted to Siriraj Hospital were separated into two groups, penicillin-susceptible (PSSP) and penicillin-nonsusceptible (PNSP). Each group was tested for susceptibilities to 12 drugs (cefuroxime, amoxicillin, chloramphenicol, tetracycline, cefotaxime, ceftriaxone, imipenem, meropenem, ciprofloxacin, ofloxacin, erythromycin and co-trimoxazole). PSSP were susceptible to cefuroxime (87.5%), amoxicillin (100%), chloramphenicol (84.7%), tetracycline (45.8%), cefotaxime (99%), ceftriaxone (99%), imipenem (99%), meropenem (100%), ciprofloxacin (76%), ofloxacin (99%), erythromycin (94.8%) and co-trimoxazole (61.5%). PNSP were resistant to most drugs, except for amoxicillin (99%), ofloxacin (99%) and ciprofloxacin (86.3%). Twenty-two pneumococcal isolates belonging to the three most common serotypes (6, 19, 23) were randomly selected for studies of the pbp2b gene with RFLP. There were 7 distinct pbp2b RFLP patterns. RFLP pattern 1 was the most predominant resistant pattern. The RFLP pattern 2 was found only in PSSP.

Bacterial study of autopsy specimens.

Autopsy reports were reviewed for the detection of infectious diseases at autopsy and to determine what extent an infectious process was involved in the patient's death. The present study was performed to analyze bacterial data of autopsy specimens in Siriraj Hospital during 1992-1999. Various autopsy specimens were cultured including heart blood, bronchus, lung, brain, cerebro-spinal fluid, pleural fluid, ascitic fluid, peritoneal fluid, liver, kidney, pericardial fluid, spleen and gall bladder From 781 autopsy specimens 502 (64.28%) were positive for bacterial pathogens. The five most common bacterial pathogens isolated from the present study were nonfermentative gram-negative rods followed by Klebsiella pneumoniae, Salmonella serogroup E, Escerichia coli and Acinetobacter anitratus, respectively. The ante mortem diagnosis by clinicians was correct 56% regarding to retrospectively analysis of septicemia/septic shock versus autopsy culture from heart blood