A Surveillance Bacteriological Study of Acute Bacterial Rhinosinusitis in Thailand and the Clinical Responses to the Culture-directed Antibiotics.

OBJECTIVE: To examine: 1) types of bacteria and antimicrobial sensitivity of commonly used antibiotics for acute bacterial rhinosinusitis (ABRS) in Thailand, 2) the effectiveness of using antibiotics according to antimicrobial sensitivity, and 3) the effectiveness of using antibiotics according to the Thai clinical practice guidelines (CPG) of ABRS. MATERIAL AND METHOD: Descriptive & experimental studies were conducted in seven tertiary hospitals in Thailand. The specimens from maxillary sinuses were taken for bacterial cultures either by maxillary sinus tap or endoscopically directed middle meatus swabs in patients with clinically diagnosed ABRS. Antimicrobial sensitivity was performed and antibiotics were prescribed according to the results of antimicrobial sensitivity or the Thai CPG of ABRS. RESULTS: A total of 113 patients were enrolled between August 2006 and April 2007, 104 cases of which were performed for bacteriological study. The incidence of bacterial growth was 60.6% (95% CI 51.0-69.4%). The most common bacteria was H. influenzae (25.0%, 95% CI 16.9-35.3%), followed by S. pneumoniae (14.3%, 95% CI 8.2-23.5%) and S. aureus (9.5%, 95% CI 4.7-17.9%), respectively, whilst M. catarrhalis was found only in 2.4% (95% CI 0.5-7.3%). Eight in 12 S. pneumoniae isolates were tested for the minimal inhibitory concentration of penicillin and found to be penicillin resistant strain in five specimens. Beta-lactamase producing H. influenzae was found in eight out of 20 isolates. H. influenzae had a tendency to be sensitive to amoxicillin/clavulanate, cefuroxime, cefpodoxime, azithromycin, clarithromycin, ofloxacin, levofloxacin and gatifloxacin, whilst S. pneumoniae had a tendency to be sensitive to amoxicillin/clavulanate, cefaclor ampicillin/sulbactam, cefuroxime, ofloxacin, levofloxacin, gatifloxacin, cefpodoxime, cefixime and cefdinir. The effectiveness of antibiotics prescription according to the Thai CPG of ABRS and antimicrobial sensitivity were comparable, 88.5% (95% CI 69.8-97.6%) and 82.2% (95% CI 67.9-92%), respectively. CONCLUSION: H. influenzae is found to be the most common bacteria in Thai ABRS, followed by S. pneumoniae and S. aureus. There is a high incidence of beta-lactamase producing H. influenzae and penicillin non-susceptible S. pneumoniae.

Bactericidal efficacy of alcohol solution in community hospital and health centers.

OBJECTIVE: To evaluate bactericidal efficacy of alcohol solution during actual use and typical storage conditions in community hospital and health centers. MATERIAL AND METHOD: The alcohol samples were collected immediately after the first bottle-opening (day 0) and on day 3, 7, 14, 21 and 30 from 10 stations in hospital and community health centers in Pone-na-kaew district, Sakon Nakhon province, Thailand, during May-July 2011. Bactericidal efficacy of these samples against Staphylococcus epidermidis, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Klebsiella pneumoniae was evaluated. Ethanol concentration was quantified by a gas chromatography method. RESULTS: Bactericidal efficacy of the alcohol samples still remained on day 30 with ethanol concentration range of 60.91-65.99% v/v. CONCLUSION: This finding should be considered as a cost-benefit model for using alcohol solution in community hospital and health centers.

Emergence of NDM-1- and IMP-14a-producing Enterobacteriaceae in Thailand.

OBJECTIVES: To detect carbapenemases in clinical isolates of Enterobacteriaceae collected from patients in a university hospital in Thailand between October 2010 and August 2011. METHODS: A total of 4818 Enterobacteriaceae isolates were screened for the presence of carbapenemases by ertapenem and imipenem disc diffusion tests. All positive screening isolates were subjected to modified Hodge test, phenylboronic acid- and EDTA-carbapenem combined disc tests and two multiplex PCRs of bla(IMP), bla(VIM), bla(SPM), bla(SIM) and bla(GIM), and of bla(KPC), bla(NDM) and bla(OXA-48). Carbapenemase-producing isolates were typed by PFGE and then characterized by antimicrobial susceptibility tests. Conjugation was performed using a broth culture mating method. RESULTS: Two isolates each of Escherichia coli, Klebsiella pneumoniae and Citrobacter freundii produced NDM-1, whereas two other isolates of K. pneumoniae produced IMP-14a. DNA fingerprints revealed that the metallo-ß-lactamase (MBL)-producing isolates were of different strains except for clonal strains of C. freundii. In vitro transfer of carbapenem resistance was successful for the eight MBL-producing isolates. All MBL producers were susceptible to colistin and tigecycline. The six NDM-producing isolates were recovered from the urine of three patients, who had no history of travel outside Thailand. Interestingly, one patient had chronic urinary tract infections caused by a K. pneumoniae strain and two strains of E. coli producing NDM-1. CONCLUSIONS: Surveillance of carbapenemases, particularly NDM-1, in Enterobacteriaceae is urgently needed to control and prevent the spread of these resistance determinants in our country.

Extensive characterizations of bacteria isolated from catheterized urine and stone matrices in patients with nephrolithiasis.

BACKGROUND: Urinary tract infections are generally known to be associated with nephrolithiasis, particularly struvite stone, in which the most common microbe found is urea-splitting bacterium, i.e. Proteus mirabilis. However, our observation indicated that it might not be the case of stone formers in Thailand. We therefore extensively characterized microorganisms associated with all types of kidney stones. METHODS: A total of 100 kidney stone formers (59 males and 41 females) admitted for elective percutaneous nephrolithotomy were recruited and microorganisms isolated from catheterized urine and cortex and nidus of their stones were analyzed. RESULTS: From 100 stone formers recruited, 36 cases had a total of 45 bacterial isolates cultivated from their catheterized urine and/or stone matrices. Among these 36 cases, chemical analysis by Fourier-transformed infrared spectroscopy revealed that 8 had the previously classified 'infection-induced stones', whereas the other 28 cases had the previously classified 'metabolic stones'. Calcium oxalate (in either pure or mixed form) was the most common and found in 64 and 75% of the stone formers with and without bacterial isolates, respectively. Escherichia coli was the most common bacterium (approximately one-third of all bacterial isolates) found in urine and stone matrices (both nidus and periphery). Linear regression analysis showed significant correlation (r = 0.860, P < 0.001) between bacterial types in urine and stone matrices. Multidrug resistance was frequently found in these isolated bacteria. Moreover, urea test revealed that only 31% were urea-splitting bacteria, whereas the majority (69%) had negative urea test. CONCLUSIONS: Our data indicate that microorganisms are associated with almost all chemical types of kidney stones and urea-splitting bacteria are not the major causative microorganisms found in urine and stone matrices of the stone formers in Thailand. These data may lead to rethinking and a new roadmap for future research regarding the role of microorganisms in kidney stone formation.

Preliminary report of SCCmec-types and antimicrobial susceptibilities of methicillin-resistant Staphylococcus aureus isolates from a university hospital in Thailand.

Methicillin-resistant Staphylococcus aureus (MRSA) has spread worldwide. It is a major cause of hospital-acquired infections in most hospitals for nearly half century. The present study was conducted to examine the antimicrobial susceptibilities and staphylococcal cassette chromosome mec (SCCmec)-type for MRSA isolates from 237 patients treated at Srinagarind Hospital between September 2002 and August 2003. Antimicrobial susceptibility testing for all isolates was performed using an agar dilution method and SCCmec-types of 81 representatives from 237 isolates were determined using multiplex PCR. The minimum inhibitory concentration (MIC) ranges for the MRSA isolates were as follows: cefazolin 8 to > or =64; erythromycin < or = 0.5 to > or =64; gentamicin < or = 0.5 to > or =64; imipenem < or = 0.5 to >16; ofloxacin < or = 0.5 to > or =64; oxacillin 16 to > or =64; tetracycline 2 to > or =64 and vancomycin < or = 0.5 to 2 microg/ml. All MRSA isolates were susceptible to vancomycin, but only 0.4% to 8.9% was susceptible to the remaining antimicrobial agents. Of the 81 isolates tested, 2 types of SCCmec were found (76 with type III and 2 with type II) and no mecA gene was detected in 3 isolates. Sixty-seven of the 78 isolates carried the mercury-resistant operon. The multilocus sequence type in isolates with type III SCCmec was ST239 and in isolates with type II SCCmec was ST5.

Elongation factor Tu on Escherichia coli isolated from urine of kidney stone patients promotes calcium oxalate crystal growth and aggregation.

Escherichia coli is the most common bacterium isolated from urine and stone matrix of calcium oxalate (CaOx) stone formers. Whether it has pathogenic role(s) in kidney stone formation or is only entrapped inside the stone remains unclear. We thus evaluated differences between E. coli isolated from urine of patients with kidney stone (EUK) and that from patients with urinary tract infection (UTI) without stone (EUU). From 100 stone formers and 200 UTI patients, only four pairs of EUK/EUU isolates had identical antimicrobial susceptibility patterns. Proteomic analysis revealed nine common differentially expressed proteins. Among these, the greater level of elongation factor Tu (EF-Tu) in EUK was validated by Western blotting. Outer membrane vesicles (OMVs) derived from EUK had greater promoting activities on CaOx crystallization, crystal growth and aggregation as compared to those derived from EUU. Neutralizing the OMVs of EUK with monoclonal anti-EF-Tu antibody, not with an isotype antibody, significantly reduced all these OMVs-induced promoting effects. Moreover, immunofluorescence staining of EF-Tu on bacterial cell surface confirmed the greater expression of surface EF-Tu on EUK (vs. EUU). Our data indicate that surface EF-Tu and OMVs play significant roles in promoting activities of E. coli on CaOx crystallization, crystal growth and aggregation.

Detection of heterogeneous, intermediate-vancomycin-resistant Staphylococcus aureus (hVISA) using low-concentration vancomycin disks.

Heterogeneous, intermediate-vancomycin-resistant Staphylococcus aureus (hVISA) represents a threat of an incurable infection since the first report in 1997. The method used to detect hVISA isolates is a population analysis profile (PAP); however, it is impractical for routine laboratory analysis. We therefore tested a simple, reliable and inexpensive method for the detection of hVISA. Eighteen isolates of hVISA and 22 of vancomycin-sensitive S. aureus (VSSA) were included. The organisms were tested by the disk diffusion method, using 15-microg vancomycin disks on four different media: Mueller-Hinton agar (MHA), MHA plus 2% NaCI (MHAS), Brain Heart Infusion agar (BHA), and BHA plus 2% NaCl (BHAS). In addition, two different inoculum sizes, bacterial suspensions adjusted to 0.5 and 2.0 McFarland, were tested. The inhibition zone was read independently by three medical technologists after incubation at 37 degrees C for 24 and 48 hours. The use of MHAS with an inoculum size of 2.0 McFarland and 48-hour incubation period yielded the highest sensitivity (94.4%), specificity (81.8%), positive predictive value (80.9%), and negative predictive value (94.7%). The disk diffusion test with 15-microg vancomycin disk is simple and may be used as a screening method for the detection of hVISA.

SCCmec IX in meticillin-resistant Staphylococcus aureus and meticillin-resistant coagulase-negative staphylococci from pigs and workers at pig farms in Khon Kaen, Thailand.

Livestock-associated meticillin-resistant Staphylococcus aureus, clonal complex (CC) 398, has been reported in Europe, whereas CC9 MRSA has mostly been found in Asia. Therefore, we aimed to detect MRSA on pig farms in north-eastern Thailand. A total of 257 nasal swabs (159 samples from pigs and 98 from pig-farm workers) were collected from three pig farms in north-eastern Thailand from 2010 to 2011. MRSA isolates were confirmed for femA and mecA genes by PCR. The MICs of eight antimicrobials, namely vancomycin (VA), cefazolin (CZ), ofloxacin (OF), tetracycline (TET), erythromycin (ER), oxacillin (OX), cefoxitin (FOX) and gentamicin (GN), were tested by agar dilution method. The virulence genes for Panton-Valentine leukocidin toxin (lukSF-PV), toxic shock syndrome toxin-1 (tst) and α-haemolysin (hla) were detected by PCR. Strain typing was performed by staphylococcal cassette chromosome (SCC) mec, agr, spa and multilocus sequence typing. Four MRSA were isolated: three from workers and one from a pig. All the MRSA isolates were resistant to OX, GN, ER, TET and CZ, and they all carried hla only. Two MRSA from humans carried SCCmec II-sequence type (ST)764-agrII, whereas the two remaining MRSA (one each from a human and a pig) contained SCCmec IX-ST9-agrII. Interestingly, meticillin-resistant coagulase-negative Staphylococcus isolates carrying SCCmec IX were also obtained from five workers and three pigs. This study suggests that the SCCmec IX element is distributed among the Staphylococcus found in pigs and pig-farm workers, and pigs may be a reservoir for MRSA in the community.

Effect of binders on airborne microorganism inactivation using TiO2 photocatalytic fluorescent lamps.

5% Degussa P25 TiO2 was spray-coated onto black-light and white-light fluorescent lamps, using five different binders, namely DURAMAX B-1000, DURAMAX D-3005, silane-69, and two polyethylene glycols with molecular weight 1000 (PEG-1000) and 700 (PEG-700). The coated lamps were tested with Staphylococcus epidermidis, Escherichia coli, spores of Bacillus subtilis and spores of Aspergillus niger. It was found that 0.5% B-1000 and 1% PEG-1000 gave the highest inactivation rates: 93-96% from coated black-light lamps and 85-88% from coated white-light lamps for bacteria. In the case of spores, 70-72% and 55-57% inactivation rates were recorded from coated black-light and coated white-light lamps, respectively. The effects of UVA irradiance and face velocity were also examined. Significant improvement was observed from coated white-light lamps when the UVA irradiance increased. High face velocity adversely affected microorganism inactivation.

Prevalence of ß-lactamase-negative ampicillin-resistant haemophilus influenzae isolated from patients of a teaching hospital in Thailand.

The aim of this study was to investigate the prevalence of ß-lactamase-negative ampicillin-resistant (BLNAR) Haemophilus influenzae isolated from patients of a teaching hospital in Thailand. Eighty-eight isolates of H. influenzae were collected between September 2005 and March 2008. All isolates were identified and characterized for biotypes and capsular types. The ß-lactamase production of these isolates was examined, and their susceptibility to the following 12 antimicrobial agents was determined: ampicillin (AMP), amoxicillin-clavulanate (AMC), cefotaxime (CTX), cefuroxime (CXM), meropenem (MEM), clarithromycin (CLR), telithromycin (TEL), tetracycline (TET), ciprofloxacin (CIP), levofloxacin (LEV), trimethoprim-sulfamethoxazole (SXT), and chloramphenicol (CHL). Of the 88 H. influenzae isolates, 69 (78.4%), 13 (14.8%), 4 (4.5%), and 2 (2.3%) were from the respiratory tract, pus, the genital tract, and blood, respectively. Half of the isolates were biotype II (44 isolates, 50%). The other half comprised biotypes I (23 isolates, 26.1%), III (15 isolates, 17.1%), and IV (6 isolates, 6.8%). All isolates were capsular non-typeable, except for 2 isolates that were type f. Antimicrobial susceptibility showed that all isolates were susceptible to AMC, CTX, MEM, TEL, CIP, and LEV (100%), whereas 96.6%, 94.3%, 80.7%, 68.2%, 50.0%, and 44.3% were susceptible to CXM, CLR, CHL, TET, AMP, and SXT, respectively. The ß-lactamase-production rate of H. influenzae isolates was 40.9%, and the prevalence of BLNAR was 18.2%.

Performance of photocatalytic lamps on reduction of culturable airborne microorganism concentration.

Reduction of viable airborne Staphylococcus epidermidis and Aspergillus niger spore concentrations using two types of photocatalytic fluorescent lamps under controlled environmental conditions (25 vs. 35°C and 55 vs. 75% relative humidity) were investigated. Visible white-light and UVA black light were in-house spray-coated with TiO(2) and then compared with a commercially coated visible white-light for microbial concentration reduction. The white-light photocatalytic lamps reduced the concentration of culturable S. epidermidis up to 92% independent of temperature or humidity change, while the black light photocatalytic lamps completely inactivated the culturable bacteria at 25°C, 55% relative humidity. Humidity seemed to alleviate UVA damage since better bacteria survival was found. For A. niger spores, rising humidity or temperature could lower their concentration or drop their culturabilities so that a difference between the natural decay and photocatalytic disinfection could not be distinguished. Reductions of total bacteria and total fungi concentrations using these lamps were also examined under uncontrolled environmental conditions in an office and a waste-storage room. It was found that photocatalytic lamps could reduce total culturable bacteria concentration from 9 to 97% and total culturable fungi concentration from 3 to 95% within irradiation time of 30-480 min, respectively. Insignificant difference in concentration reduction among these photocatalytic lamps was pronounced.

CMY-2, CMY-8b, and DHA-1 plasmid-mediated AmpC ß-lactamases among clinical isolates of Escherichia coli and Klebsiella pneumoniae from a university hospital, Thailand.

Between February 2005 and January 2006 in Srinagarind Hospital, Thailand, 44 from 1730 isolates (2.5%) of Escherichia coli and 8 from 982 isolates (0.8%) of Klebsiella pneumoniae were found to produce plasmid-mediated AmpC ß-lactamases (pAmpCs) as detected by a cefoxitin-Hodge test followed by a multiplex polymerase chain reaction (PCR) technique. Fifteen of the 52 pAmpC-producing isolates also produced extended-spectrum ß-lactamases. The ampC genes found in both organisms were bla(CMY-2) (46 isolates), bla(CMY-8b) (4 isolates), and bla(DHA-1) (2 isolates). These genes were present on plasmids. Twenty-five of the 46 CMY-2-producing isolates could transfer cefoxitin resistance to E. coli UB1637 by conjugation. More than 90% of the pAmpC-producing isolates were resistant to cefoxitin, but 80% to 90% of them were susceptible or intermediately susceptible to ceftazidime or cefotaxime. Enterobacterial repetitive intergenic consensus PCR analysis revealed that most isolates were of different strains, indicating the ease of transmission of these resistance determinants. This is the first report of CMY-2, CMY-8b, and DHA-1 ß-lactamases in Thai isolates.

Detection of heterogeneous, intermediate-vancomycin-resistant Staphylococcus aureus (hVISA) using low-concentration vancomycin disks.

Heterogeneous, intermediate-vancomycin-resistant Staphylococcus aureus (hVISA) represents a threat of an incurable infection since the first report in 1997. The method used to detect hVISA isolates is a population analysis profile (PAP); however, it is impractical for routine laboratory analysis. We therefore tested a simple, reliable and inexpensive method for the detection of hVISA. Eighteen isolates of hVISA and 22 of vancomycin-sensitive S. aureus (VSSA) were included. The organisms were tested by the disk diffusion method, using 15-microg vancomycin disks on four different media: Mueller-Hinton agar (MHA), MHA plus 2% NaCI (MHAS), Brain Heart Infusion agar (BHA), and BHA plus 2% NaCl (BHAS). In addition, two different inoculum sizes, bacterial suspensions adjusted to 0.5 and 2.0 McFarland, were tested. The inhibition zone was read independently by three medical technologists after incubation at 37 degrees C for 24 and 48 hours. The use of MHAS with an inoculum size of 2.0 McFarland and 48-hour incubation period yielded the highest sensitivity (94.4%), specificity (81.8%), positive predictive value (80.9%), and negative predictive value (94.7%). The disk diffusion test with 15-microg vancomycin disk is simple and may be used as a screening method for the detection of hVISA.