Habsah Hasan

Review on Zinc Oxide Nanoparticles: Antibacterial Activity and Toxicity Mechanism

Antibacterial activity of zinc oxide nanoparticles (ZnO-NPs) has received significant interest worldwide particularly by the implementation of nanotechnology to synthesize particles in the nanometer region. Many microorganisms exist in the range from hundreds of nanometers to tens of micrometers. ZnO-NPs exhibit attractive antibacterial properties due to increased specific surface area as the reduced particle size leading to enhanced particle surface reactivity. ZnO is a bio-safe material that possesses photo-oxidizing and photocatalysis impacts on chemical and biological species. This review covered ZnO-NPs antibacterial activity including testing methods, impact of UV illumination, ZnO particle properties (size, concentration, morphology, and defects), particle surface modification, and minimum inhibitory concentration. Particular emphasize was given to bactericidal and bacteriostatic mechanisms with focus on generation of reactive oxygen species (ROS) including hydrogen peroxide (H2O2), OH− (hydroxyl radicals), and O2−2 (peroxide). ROS has been a major factor for several mechanisms including cell wall damage due to ZnO-localized interaction, enhanced membrane permeability, internalization of NPs due to loss of proton motive force and uptake of toxic dissolved zinc ions. These have led to mitochondria weakness, intracellular outflow, and release in gene expression of oxidative stress which caused eventual cell growth inhibition and cell death. In some cases, enhanced antibacterial activity can be attributed to surface defects on ZnO abrasive surface texture. One functional application of the ZnO antibacterial bioactivity was discussed in food packaging industry where ZnO-NPs are used as an antibacterial agent toward foodborne diseases. Proper incorporation of ZnO-NPs into packaging materials can cause interaction with foodborne pathogens, thereby releasing NPs onto food surface where they come in contact with bad bacteria and cause the bacterial death and/or inhibition.

The prevalence of acute respiratory symptoms and role of protective measures among Malaysian hajj pilgrims.

BACKGROUND Respiratory symptoms including cough, runny nose, sore throat, and fever are the most common clinical manifestations faced by hajj pilgrims in Mecca. The aim of the study was to determine the prevalence of respiratory symptoms among Malaysian hajj pilgrims and the effect of a few protective measures taken by hajj pilgrims to reduce respiratory symptoms. METHODS A cross-sectional study was conducted by distributing survey forms to Malaysian hajj pilgrims at transit center before flying back to Malaysia. The recruitment of respondents to the survey was on a voluntary basis. RESULTS A total of 387 survey forms were available for analysis. The mean age was 50.4 +/- 11.0 years. The common respiratory symptoms among Malaysian hajj pilgrims were: cough 91.5%, runny nose 79.3%, fever 59.2%, and sore throat 57.1%. The prevalence of hajj pilgrims with triad of cough, subjective fever, and sore throat were 40.1%. The symptoms lasted less than 2 weeks in the majority of cases. Only 3.6% did not suffer from any of these symptoms. Seventy-two percent of hajj pilgrims received influenza vaccination before departure and 72.9% wore facemasks. Influenza vaccination was not associated with any of respiratory symptoms but it was significantly associated with longer duration of sore throat. Wearing masks was significantly associated with sore throat and longer duration of sore throat and fever. CONCLUSIONS The prevalence of respiratory symptoms was high among Malaysian hajj pilgrims and the current protective measures seemed inadequate to reduce it. Beside standardization of the term used in hajj studies, more collaborative effort should be taken to reduce respiratory symptoms. The hajj authority should prepare for the challenge of pandemic influenza by providing more healthcare facilities and implementation of more strict measures to reduce the transmission of pandemic influenza strain among hajj pilgrims.

Color thresholding method for image segmentation algorithm of Ziehl-Neelsen sputum slide images

Most of the thresholding procedures involved setting of boundaries based on grey values or intensities of image pixels. In this paper, the thresholding is to be done based on color values in images of Ziehl-Neelsen sputum slides. The color thresholding technique is being carried out based on the adaptation and slight modification of the grey level thresholding algorithm. Multilevel thresholding has been conducted to the RGB color information of the bacterium to extract it from the sputum and other objects. Five types of different images have been used in the study of color information. The results showed that by using the selected threshold values, the image segmentation technique has been able to separate the sputum from the mycobacterium.

Detection of blaIMP4 and blaNDM1 harboring Klebsiella pneumoniae isolates in a university hospital in Malaysia

Background Antibiotic resistance among Enterobacteriaceae posts a great challenge to the health care service. The emergence of carbapenem-resistant Klebsiella pneumoniae (CRKP) is attracting significant attention due to its rapid and global dissemination. The infection is associated with significant morbidity and mortality, thus creating challenges for infection control and managing teams to curb the infection. In Southeast Asia, there have been limited reports and subsequent research regarding CRKP infections. Thus, the study was conducted to characterize CRKP that has been isolated in our setting. Methods A total of 321 K. pneumoniae were included in the study. Each isolate went through an identification process using an automated identification system. Phenotypic characterization was determined using disk diffusion, modified Hodge test, Epsilometer test, and inhibitor combined disk test. Further detection of carbapenemase genes was carried out using polymerase chain reaction and confirmed by gene sequence analysis. Results All together, 13 isolates (4.05%) were CRKP and the majority of them were resistant to tested antibiotics except colistin and tigercycline. Among seven different carbapenemase genes studied (bla KPC, bla IMP, bla SME, bla NDM, bla IMI, bla VIM, and bla OXA), only two, bla IMP4 (1.87%) and bla NDM1 (2.18%), were detected in our setting. Conclusion Evidence suggests that the prevalence of CRKP in our setting is low, and knowledge of Carbapenem-resistant Enterobacteriaceae and CRKP has improved and become available among clinicians.

Comparison of antimicrobial resistance in neonatal and adult intensive care units in a tertiary teaching hospital

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.

Methicillin-resistant Staphylococcus aureus nosocomial infection trends in Hospital Universiti Sains Malaysia during 2002-2007.

Background and Objectives: Methicillin-resistant Staphylococcus aureus (MRSA) is a major nosocomial pathogen that causes severe morbidity and mortality in many hospitals worldwide. The aim of the present study was to assess the burden of MRSA nosocomial infection, its association with factors of interest, and its antimicrobial susceptibility. Methods: This was a retrospective analysis of a database of all S aureus that were cultured from patients admitted to the different wards of Hospital Universiti Sains Malaysia (HUSM) over a period of 6 years. Results: The MRSA infections rate was 10.0 per 1000 hospital admissions. The incidence density rate of MRSA infections during the study period was 1.8 per 1000 patient-days, with annual rates ranging from 0.95 to 3.47 per 1000 patient-days. Duration of hospitalization, previous antibiotic use, and bedside invasive procedures were significantly higher among MRSA than methicillin-sensitive S aureus patients (P>.05). The highest number of MRSA infections were found in orthopedic wards (25.3%), followed by surgical wards (18.2%) and intensive care units (ICUs) (16.4%). All MRSA isolates were resistant to erythromycin (98.0%), co-trimoxazole (94.0%) and gentamicin (92.0%). Clindamycin was the best antibiotic with only 6% resistance. All MRSA isolates were sensitive to vancomycin. Conclusion: The rate of nosocomial MRSA infection per 1000 admissions was higher than that in other studies. The three factors associated most significantly with acquired MRSA infections included duration of hospitalization, antibiotic use, and bedside invasive procedures. This study confirmed that vancomycin-resistant S aureus has not yet been established in HUSM.

The prevalence and preventive measures of the respiratory illness among Malaysian pilgrims in 2013 hajj season

Abstract Background. Respiratory illness continues to exert a burden on hajj pilgrims in Makkah. The purpose of this study is to determine the prevalence of respiratory illness and its associated factors among Malaysian hajj pilgrims in 2013 and to describe its preventive measures. Methods. A cross-sectional study was conducted in Makkah and Malaysia during the 2013 hajj season. A self-administered proforma on social demographics, previous experience of hajj or umrah, smoking habits, co-morbid illness and practices of preventive measures against respiratory illness were obtained. Results. A total of 468 proforma were analysed. The prevalence of the respiratory illness was 93.4% with a subset of 78.2% fulfilled the criteria for influenza-like illness (ILI). Most of them (77.8%) had a respiratory illness of <2 weeks duration. Approximately 61.8% were administered antibiotics but only 2.1% of them had been hospitalized. Most of them acquired the infection after a brief stay at Arafat (81.2%). Vaccination coverages for influenza virus and pneumococcal disease were quite high, 65.2% and 59.4%, respectively. For other preventive measures practices, only 31.8% of them practiced good hand hygiene, ∼82.9% of pilgrims used surgical face masks, N95 face masks, dry towels, wet towels or veils as their face masks. Nearly one-half of the respondents (44.4%) took vitamins as their food supplement. Malaysian hajj pilgrims with previous experience of hajj (OR 0.24; 95% CI 0.10–0.56) or umrah (OR 0.19; 95% CI 0.07–0.52) and those who have practiced good hand hygiene (OR 0.35; 95% CI 0.16–0.79) were found to be significantly associated with lower risk of having respiratory illness. Otherwise, pilgrims who had contact with those with respiratory illness (OR 2.61; 95% CI 1.12–6.09) was associated with higher risk. Conclusions. The prevalence of respiratory illness remains high among Malaysian hajj pilgrims despite having some practices of preventive measures. All preventive measures which include hand hygiene, wearing face masks and influenza vaccination must be practiced together as bundle of care to reduce respiratory illness effectively.

Multidrug-resistant tuberculosis and risk factors associated with its development: a retrospective study

INTRODUCTION Multidrug-resistant tuberculosis (MDR-TB) has emerged as a major clinical public health threat and challenges the national TB control program in Malaysia. Data that elaborates on the risk factors associated with the development of MDR-TB is highly limited in this country. This study was aimed to determine the risk factors associated with the development of MDR-TB patients in peninsular Malaysia. METHODOLOGY This was a case control study; the data were collected from medical records of all the registered MDR-TB patients at five referral TB hospitals in peninsular Malaysia from January 2010 to April 2014. The 105 cases were all confirmed by a positive sputum culture of Mycobacterium tuberculosis for MDR-TB and extensively drug-resistant (XDR)-TB. As a comparison, a total of 209 non-MDR-TB cases were randomly selected as controls. RESULTS A total of 105 MDR-TB and 209 non MDR-TB patients were studied. The risk factors associated with MDR-TB within the multivariate analysis were previous tuberculosis treatment, HIV infection, being an immigrant, and high load of positive for acid-fast bacillus (AFB) smear. CONCLUSIONS The findings of this study revealed that patients who had received previous treatment for tuberculosis, were infected with HIV, were immigrants, and had a high burden of positive testing for AFB smear were more likely to have MDR-TB. An enhanced understanding of the risk factors associated with MDR-TB strains is imperative in the development of a national policy for public health interventions.

Rapid detection of methicillin-resistant Staphylococcus aureus by a newly developed dry reagent-based polymerase chain reaction assay

BACKGROUND/PURPOSE Methicillin-resistant Staphylococcus aureus (MRSA) is a major pathogen responsible for significant numbers of nosocomial and community-acquired infections worldwide. Molecular diagnosis for MRSA nasal carriers is increasingly important for rapid detection and screening of MRSA colonization because the conventional methods are time consuming and labor intensive. However, conventional polymerase chain reaction (PCR) tests still require cold-chain storage as well as trained personnel, which makes them unsuitable for rapid high-throughput analysis. The aim of this study was to develop a thermostabilized PCR assay for MRSA in a ready-to-use form that requires no cold chain. METHODS The thermostabilized PCR assay detects the following targets simultaneously: (1) 16S rRNA of the Staphylococcus genus; (2) femA gene specific for S. aureus; (3) mecA gene conferring methicillin resistance; and (4) lukS gene, which encodes the virulent toxin. The thermostabilized PCR incorporates an internal amplification control that helps to verify the presence of PCR inhibitors in samples. PCR reagents and specific primers were lyophilized into a pellet form with an enzyme stabilizer. RESULTS The PCR was validated with 235 nasal swabs specimens and was found to be 100% sensitive and specific. The stability of the thermostabilized PCR was evaluated using the Q10 method and it was found to be stable for approximately 6 months at 24 °C. The limit of detection of thermostabilized PCR assay was determined by probit regression (95% confidence interval) was 10(6) colony forming units at the bacterial cell level and 10 ng of DNA at the genomic DNA level, which is comparable with conventional PCR methods. CONCLUSION A rapid thermostabilized PCR assay that requires minimal pipetting steps and is cold chain-free was developed for detecting MRSA nasal carriers.

Evaluation of the Atlas Helicobacter pylori Stool Antigen Test for Diagnosis of Infection in Adult Patients

BACKGROUND Helicobacter pylori (H. pylori) is one of the most important causes of dyspepsia and gastric cancer and diagnosis can be made by invasive or non-invasive methods. The Atlas Helicobacter pylori antigen test is a new rapid non-invasive method which is simple to conduct. The aim of this study was to determine its sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy. MATERIALS AND METHODS This prospective study was conducted between July 2012 and December 2013. Stool samples of 59 dyspeptic patients who underwent upper endoscopy were evaluated for H. pylori stool antigen. RESULTS From the 59 patients who participated in this study, there were 36 (61%) males and 23 (39%) females. H. pylori was diagnosed in 24 (40.7%) gastric biopsies, 22 (91.7 %) of these being positive for the Atlas H. pylori antigen test. The sensitivity, specificity, PPV, NPV and accuracy were 91.7%, 100%, 100%, 94.6% and 96.6% respectively. CONCLUSIONS The Atlas H. pylori antigen test is a new non-invasive method which is simple to perform and avails reliable results in a few minutes. Thus it can be the best option for the diagnosis of H. pylori infection due to its high sensitivity and specificity.