The discovery of quorum sensing in Proteobacteria and its function in regulating virulence determinants makes it an attractive alternative towards attenuation of bacterial pathogens. In this study, crude extracts of Phyllanthus amarus Schumach. & Thonn, a traditional Chinese herb, were screened for their anti-quorum sensing properties through a series of bioassays. Only the methanolic extract of P. amarus exhibited anti-quorum sensing activity, whereby it interrupted the ability of Chromobacterium violaceum CVO26 to response towards exogenously supplied N-hexanoylhomoserine lactone and the extract reduced bioluminescence in E. coli [pSB401] and E. coli [pSB1075]. In addition to this, methanolic extract of P. amarus significantly inhibited selected quorum sensing-regulated virulence determinants of Pseudomonas aeruginosa PA01. Increasing concentrations of the methanolic extracts of P. amarus reduced swarming motility, pyocyanin production and P. aeruginosa PA01 lecA::lux expression. Our data suggest that P. amarus could be useful for attenuating pathogens and hence, more local traditional herbs should be screened for its anti-quorum sensing properties as their active compounds may serve as promising anti-pathogenic drugs.
Enteroendocrine cells are the largest population of hormone-producing cells in the body and play important roles in many aspects of body functions. The enteroendocrine cell population is divided into different subpopulations that secrete different hormones and peptides. Characterization of each subpopulation is particularly useful for analyzing the cellular mechanisms responsible for specific cell types. Therefore, the necessity of a pure cell line for a specific study purpose was the important motivation for the separation of cell lines for each subpopulation of enteroendocrine cells. The present research introduces a method for the isolation of L-cells, one of the important subpopulations of enteroendocrine cells. The antibiotic selection method was conducted in order to isolate the L-cells from a heterogonous population of intestinal cell line. In this method, a neomycin resistance gene (as selected marker) was expressed under the control of a specific promoter of L-cells. After transfection of manipulated plasmid, only the cells which determine the specific promoter and express neomycin resistance protein would be able to survive under Geneticin antibiotic treatment condition. In order to confirm that the isolated cells were L-cells, reverse transcriptase polymerase chain reaction (PCR) and quantitative PCR assays were performed. Based on the results, the isolated cells were pure L-cells that could be able to express specific mRNA of L-cells efficiently. This technique provides a unique method for the isolation and purification of any cell line. The purified isolated L-cells by this method can be used for future studies and for analyzing cellular mechanisms that involve L-cells' functions.
Seven sulfonamides, trimethoprim, five macrolides, lincomycin and three tetracyclines were measured in 150 water samples of sewage, livestock and aquaculture wastewater, and river and coastal waters, in five tropical Asian countries. The sum of the concentrations of the target antibiotics in sewage and heavily sewage-impacted waters were at sub- to low-ppb levels. The most abundant antibiotic was sulfamethoxazole (SMX), followed by lincomycin and sulfathiazole. The average concentration of SMX in sewage or heavily sewage-impacted waters was 1720 ng/L in Vietnam (Hanoi, Ho Chi Minh, Can Tho; n=15), 802ng/L in the Philippines (Manila; n=4), 538 ng/L in India (Kolkata; n=4), 282 ng/L in Indonesia (Jakarta; n=10), and 76 ng/L in Malaysia (Kuala Lumpur; n=6). These concentrations were higher than those in Japan, China, Europe, the US and Canada. A predominance of sulfonamides, especially SMX, is notable in these tropical countries. The higher average concentrations, and the predominance of SMX, can be ascribed to the lower cost of the antibiotics. Both the concentration and composition of antibiotics in livestock and aquaculture wastewater varied widely. In many cases, sulfamethazine (SMT), oxytetracycline (OTC), lincomycin, and SMX were predominant in livestock and aquaculture wastewater. Both human and animal antibiotics were widely distributed in the respective receiving waters (i.e., the Mekong River and Manila Bay). SMT/SMX ratios indicate a significant contribution from livestock wastewater to the Mekong River and nearby canals, with an estimated ~10% of river water SMX derived from such wastewater. Mass flow calculations estimate that 12 tons of SMX is discharged annually from the Mekong River into the South China Sea. Riverine inputs of antibiotics may significantly increase the concentration of such antibiotics in the coastal waters.
The current study evaluates the impact of high saturated fat feeding in rat model of experimental nephrotoxicity induced by gentamicin. Sprague-Dawley rats weighing 200 g were randomized into four groups; the first one received the standard rodents chow for 8 weeks and was treated as control, the second group (HFD)received an experimental high fat diet rich in palm kernel oil (40% of Calories as fat) for the same period. The third group (HFDG) was given 80 mg/kg (body weight)/day gentamicin sulphate intraperitoneally during the last 24 days of the feeding period while the fourth group was given gentamicin as above along with the standard rodents chow. Renal function was assessed through measuring serum creatinine, creatinine clearance and absolute and fractional excretion of both sodium and potassium. At the end, rats underwent a surgical procedure for blood pressure measurement. Renal function study showed a stronger nephrotoxicity for HFDG group. Hypertension was observed in HFD group while the pressure declined after gentamicin co-administration. Overall, changing the feeding behavior toward using more SAFFAs for rats injected with gentamicin promotes the progression of renal failure.
A cross-sectional study was conducted to explore clincians' baseline knowledge, practice beliefs and acceptance of intravenous (IV)-to-oral antibiotic switching practice in Hospital Pulau Pinang. The factors most highly rated for antibiotic conversion were the ability to maintain oral intake (85.6%) and microbiology etiology (85.0%). Majority of the clinicians (76%) agreed with the traditional clinical rule that "patient should be afebrile for 24 hours before IV-to-oral switch". Specialists and consultants had the highest knowledge score among the clinicians. However, they were generally less positive about a guideline being integrated into practice.
Methicillin-resistant Staphylococcus aureus (MRSA) is well known for its epidemicity, with the emergence of new clones on a daily basis. Diversity in the clonal types of MRSA challenges the success of treatment, as different clones respond to different sets of antibiotics. However, the antibiotic susceptibility among the isolates within the same clones is largely unexplored. In a previous study on MRSA epidemiology in Malaysia, we identified six major clonal complexes (ST-239-CC8, ST-1-CC1, ST-188-CC1, ST-22-CC22, ST-7-CC7 and ST-1283-CC8). In the present study, we investigated the antibiotic susceptibility patterns of isolates of different clones. Three hundred and eighty-nine MRSA isolates were subjected to the disc diffusion test, oxacillin minimum inhibitory concentration (MIC) determination and assessment of the distribution of macrolide, lincosamide and streptogramin B (MLS(B)) resistance genes. Thirty-six different antibiotic profiles were observed: 30 (83.3 %) among ST-239, 2 (5.6 %) among ST-1283 and 1 (2.8 %) each for ST-1, ST-7, ST-22 and ST-188. All ST-239 (362, 9 %) isolates were multiple drug-resistant (MDR; resistant to more than three classes of antibiotics) and had oxacillin MICs >256 mg/l. Among the 385 clindamycin-resistant isolates, 375 (96.4 %) illustrated inducible resistance (D-zone-positive), while 10 (2.6 %) showed constitutive resistance. The vast majority of the macrolide-resistant isolates carried the ermA gene (95.1 %), followed by ermC (12.9 %). Diversity in the antibiotic susceptibilities of isolates within the clones emphasises the need for continuous surveillance of MDR strains to prescribe the correct antibiotic rather than empirical treatment. This will likely reduce the emergence of new endemic or epidemic resistant MRSA clones.
Carbapenems are the primary choice of treatment for severe Pseudomonas aeruginosa infection. However, the emergence of carbapenem resistance due to the production of metallo-β-lactamases (MBLs) is of global concern. In this study, 90 imipenem- (IPM- or IP-) resistant P. aeruginosa (IRPA) isolates, including 32 previously tested positive and genotyped for MBL genes by PCR, were subjected to double-disk synergy test (DDST), combined disk test (CDT), and imipenem/imipenem-inhibitor (IP/IPI) E-test to evaluate their MBLs detection capability. All three methods were shown to have a sensitivity of 100%. However, DDST was the most specific of the three (96.6%), followed by IP/IPI E-test interpreted based on the single criteria of IP/IPI ≥8 as positive (62.1%), and CDT was the least specific (43.1%). Based on the data from this evaluation, we propose that only IRPA with IP MIC >16 μg/mL and IP/IPI ≥8 by IP/IPI E-test should be taken as positive for MBL activity. With the new dual interpretation criteria, the MBL IP/IPI E-test was shown to achieve 100% sensitivity as well as specificity for the IRPA in this study. Therefore, the IP/IPI E-test is a viable alternative phenotypic assay to detect MBL production in IRPA in our population in circumstances where PCR detection is not a feasible option.
Paraspinal abscess and spondylodiscitis due to Citrobacter koseri is a very rare condition. We report a remarkable case of Citrobacter koseri bacteraemia complicated by paraspinal abscess and spondylodiscitis in a patient who has successfully been treated in our hospital. Our patient demonstrates one of the common challenges in the practice of infectious disease medicine, wherein an innocuous presentation may and often underlie a serious infection. This case report elucidates to us that the diagnosis of a paraspinal abscess and spondylodiscitis requires a high index of suspicion in at risk patient presenting with compatible signs and symptoms.
Matched MeSH terms: Anti-Bacterial Agents/therapeutic use
This study was conducted to detect the presence of heterogenous vancomycin-intermediate Staphylococcus aureus (heteroVISA) among MRSA isolates in a major hospital. Forty-three MRSA isolates with vancomycin MIC 2 microg/ml collected in 2009 was screened for heteroVISA using Etest Glycopeptide Resistance Detection (GRD) and confirmed by population analysis profile-area under curve method. The genetic relatedness of heteroVISA strains with other MRSA was examined by pulsed-field gel electrophoresis (PFGE) method. Two isolates were shown to be heteroVISA and derived from the same clone. This showed that heteroVISA strains were already present among our local strains since 2009 and were genetically related to other susceptible strains.
Intrahospital variations in antimicrobial profiles may be related to many factors. This study compared causative agents of nosocomial bloodstream infections between a neonatal intensive care unit (NICU) that adopted a ward-tailored antibiotic policy and adult intensive care units (ICUs). Data on organisms from blood cultures obtained from the respective wards between 2005 and 2009 were analyzed. Compared with the adult ICUs, the NICU had a higher frequency of Enterobacteriacae and lower frequencies of typical hospital-acquired pathogens (eg, Klebsiella pneumoniae, 17.4% vs 10.0% [P < .001]; Acinetobacter baumannii, 3.9% vs 11.6% [P < .001]). Antibiotic resistance of gram-negative organisms was also significantly lower in the NICU, including resistance to imipenem (5.7% vs 32.1%; P < .001), amikacin (8.8% vs 30.3%), and ceftriaxone (36.1% vs 74.6%; P < .001). This could possibly be due to the ward-tailored antibiotic policy adopted by the NICU but not by the other ICUs.
The In vitro susceptibility of clinical and environmental isolates of Acinetobacter baumannii to tigecycline and other antibiotics was determined by disk diffusion method. The E-test was used to determine the minimum inhibitory concentration (MIC). The growth curves of tigecycline treated environmental and clinical strains were established. Fifty-seven percent and 75% of the clinical and environmental isolates were MDR strains, respectively. Ninety-five percent of the clinical isolates were susceptible to tigecycline and 5% showed intermediate resistance with MIC ranging between 0.032 and 3 mg/l. Tigecycline susceptible and intermediate resistance among the environmental isolates were 40% and 60%, respectively, with a significantly lower MIC range of 0.5-4 mg/l. The bacterial growth curves demonstrated the higher ability of the environmental strains to tolerate the antibiotic effects than the clinical strains. The relatively high resistance profile among the environmental isolate suggests an insidious emergence of tigecycline resistance amongst A. baumannii. Strict infection control procedures are imperative to prevent the dissemination of tigecycline-resistant A. baumannii strains in the hospital environment.
A 10 year-old Iban girl presented with severe odynophagia for 4 days and subcutaneous emphysema. Clinically, her neck was tender with crepitus. Lateral neck radiograph showed multiple linear radiolucent shadows at retropharyngeal space. Flexible nasopharyngolaryngoscope revealed a tunnel behind upper oesophagus with slough and there was pooling of saliva at pyriform sinus. Feeding via nasogastric tube was started and empirical treatment for fungal and bacterial infection was commenced. Subsequent computed tomography of neck and thorax showed a 15-long blind tract at subglottic region posterior to oesophagus (prevertebral region), extending to superior mediastinum just before carina at T3/T4 level, represent abscess. Hourly suctioning of the remaining abscess in the blind tract with 10ml-syringe was done.
Matched MeSH terms: Anti-Bacterial Agents/therapeutic use
We report for the first time on the prevalence, antibiotic resistance and RAPD types of Campylobacter species in ducks and duck related environmental samples in Malaysia. Samples were examined by enrichment in Bolton Broth followed by plating onto modified Charcoal Cefoperazone Deoxycholate agar (mCCDA) and/or plating directly onto mCCDA. A total of 643 samples were screened, and the prevalence of Campylobacter spp. in samples from different sources ranged from 0% to 85%. The method of isolation had a significant (P<0.05) effect on the isolation rate. One hundred and sixteen Campylobacter isolates, comprising of 94 Campylobacter jejuni, 19 Campylobacter coli and three Campylobacter lari, were examined for their sensitivity to 13 antibiotics. Majority of the C. jejuni isolates were resistant to cephalothin (99%), tetracycline (96%), suphamethoxazole/trimethoprim (96%), and very few were resistant to gentamicin (5%), chloramphenicol (7%) and erythromycin (1%). All C. coli isolates were resistant to cephalothin, nalidixic acid, norfloxacin and tetracycline but susceptible to chloramphenicol, erythromycin and gentamicin. The three C. lari isolates were resistant to all the antibiotics tested except chloramphenicol and gentamicin (1/3 and 2/3 susceptible, respectively). Genetic diversity of Campylobacter isolates were determined using random amplification of polymorphic DNA (RAPD). C. jejuni and C. coli isolates belong to fifty-eight and twelve RAPD types, respectively.
BACKGROUND: Based on the `European Position Paper on Rhinosinusitis and Nasal polyps (EP3OS 2007)`, this study aimed to investigate general practitioners (GPs) and other specialists` understanding when managing patients with acute rhinosinusitis (ARS) in Asia.
METHODOLOGY: Among a total of 2662 questionnaires completed, 2524 (94.8%) were valid for analysis. There were 1308 GPs (51.8%), 989 otolaryngologists (39.2%) and 227 paediatricians (9%) from Mainland China, Hong Kong, Indonesia, India, Malaysia, Pakistan, Philippines, Singapore, Thailand and Taiwan.
RESULTS: ARS is affecting an estimated 6 - 10% of patients seen in a daily out-patient practice. The EP3OS criteria are well supported by Asian physicians (94.1%). Most physicians (62.7%) agreed that radiological investigation is not needed to diagnose ARS. However, even for mild ARS (common cold), medical treatments were still recommended by 87% of GPs, 83.9% of otolaryngologists, and 70% of paediatricians. The top three first-line treatments prescribed were antihistamines (39.2%), nasal decongestants (33.6%), and antibiotics (29.5%). Antibiotics usage increased as the first line treatment of moderate (45.9%) and severe (60.3%) ARS.
CONCLUSION: ARS is commonly managed by GPs, otolaryngologists, and paediatricians in Asia. However, understanding of the management of ARS needs further improvement to minimize unnecessary use of radiological investigations, overuse of antibiotics, and under use of nasal corticosteroids.
Matched MeSH terms: Anti-Bacterial Agents/therapeutic use
Salmonella infections remain a major public health problem in developing countries. The occurrence of infections caused by antimicrobial-resistant Salmonella has been on the rise complicating the available therapeutic options. The study aimed to determine the antibiograms and genotypes of prevalent Salmonella serotypes.
INTRODUCTION: Public knowledge and attitudes towards antibiotics play a vital role in the success of the treatment process. This study aimed to assess public knowledge and attitudes toward antibiotic usage which could serve as baseline data for future studies within a government hospital setting in Malaysia.
METHODOLOGY: A self-administered cross-sectional survey involving 408 respondents was conducted using a validated questionnaire at an outpatient pharmacy department in Penang Hospital, Malaysia, from February to March 2009.
RESULTS: Nearly 55% of the respondents had a moderate level of knowledge. Three quarters of the respondents (76.7%) could correctly identify that antibiotics are indicated for the treatment of bacterial infections. However, 67.2% incorrectly thought that antibiotics are also used to treat viral infections. About 59.1% of the respondents were aware of antibiotic resistance phenomena in relation to overuse of antibiotics. With regard to attitudes, 38% believed that taking antibiotics when having cold symptoms could help them to recover faster, while 47.3% expected antibiotics to be prescribed for common cold symptoms. Age, race and educational level were among the demographic characteristics significantly associated with knowledge and attitudes toward antibiotic use. Poor level of knowledge was found in less than one-third of the respondents whereas more than one-third of the respondents wrongly self-medicate themselves with antibiotics once they have a cold.
CONCLUSION: Educational interventions are needed to promote prudent use of antibiotics among the public.
Study site: outpatient pharmacy, Hospital Pulau Pinang, Malaysia
From January 2008 to December 2009, 433 Streptococcus pneumoniae strains were examined to determine the serotype distribution and susceptibility to selected antibiotics. About 50% of them were invasive isolates. The strains were isolated from patients of all age groups and 33.55% were isolated from children below 5 years. The majority was isolated from blood (48.53%) and other sterile specimens (6.30%). Community acquired pneumonia (41.70%) is the most common diagnosis followed by sepsis (9.54%). Serotyping was done using Pneumotest Plus-Kit and antibiotic susceptibility pattern was determined by modified Kirby-Bauer disk diffusion method and measurement of minimum inhibitory concentration (MIC) using E-test strip. Ten most common serotypes were 19F (15.02%), 6B (10.62%), 19A (6.93%), 14 (6.70%), 1 (5.08%), 6A (5.08%), 23F (4.85%), 18C (3.93%), 3 (2.08%) and 5 (1.85%). Penicillin MIC ranged between ≤ 0.012-4 μg/ml with MIC₉₀ of 1 μg/ml. Penicillin resistant rate is 31.78%. The majority of penicillin less-susceptible strains belonged to serotype 19F followed by 19A and 6B. Based on the serotypes distribution 22 (44.00%), 28 (56.00%) and 39 (78.00%) of the invasive isolates from children ≤ 2 years were belonged to serotypes included in the PCV7, PCV10 and PCV13, respectively.
OBJECTIVE: Bacterial resistance to antibiotics is the single most important determinant of treatment success. The objective of this study was to determine the prevalence of Helicobacter pylori resistance to clarithromycin, amoxicillin, metronidazole, tetracycline, levofloxacin, rifabutin, and furazolidone in our local bacterial strains.
METHODS: Samples from consecutive ninety patients were obtained for culture and sensitivity testing. Resistance to individual antibiotics were tested using the E-test and MIC(90) read from the strips. Resistance to rifampicin and nitrofurantoin were used as a surrogate for rifabutin and furazolidine.
RESULTS: There was a high prevalence of resistance to metronidazole 68/90 (75.5%). No male (34/45 (75.5%) versus female (35/45 (77.7%) difference in frequency of metronidazole resistance was noted (p = 1.000). There was zero resistance (0) to clarithromycin, levofloxacin, amoxicillin, and nitrofurantoin/furazolidone. Resistance to rifampicin/rifabutin was for breakpoints of 1 and 4 μg/mL of 14.4 and 2.2% respectively.
CONCLUSIONS: Although there was high bacterial resistance to metronidazole, the absence of resistance particularly to the key antibiotics used in H. pylori eradication therapy: clarithromycin and levofloxacin is reassuring to note. Continued monitoring of antibiotic resistance should be carried out.
The antibacterial activity of Vernonia cinerea (L.) extract was investigated using the broth dilution method. The extract showed a favorable antimicrobial activity against Pseudomonas aeruginosa with a minimum inhibition concentration (MIC) value of 3.13 mg/mL. V. cinerea extract at (1/2), 1, or 2 times the MIC significantly inhibited bacterial growth with a noticeable drop in optical density (OD) of the bacterial culture, thus confirming the antibacterial activity of the extract on P. aeruginosa. Imaging using scanning (SEM) and transmission (TEM) electron microscopy was done to determine the major alterations in the microstructure of the extract-treated P. aeruginosa. The main abnormalities noted via SEM and TEM studies were the alteration in morphology of the bacterial cells. The main reason for this destruction was the severe alterations of the cell wall with the formation of holes, invaginations, and morphological disorganization caused by the extract. The authors conclude that the extract may be used as a candidate for the development of antimicrobial agents.