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Perlindungan biokakisan keluli karbon akibat bakteria penurun sulfat yang dipencil daripada minyak mentah tropika

Mohd Nazri Idris, Abdul Razak Daud, Nurakma Mahat, Norinsan Kamil Othman, Fathul Karim Sahrani

Sains Malaysiana, 2016;45:1835-1841.

Ancaman biokakisan akibat aktiviti bakteria penurun sulfat (SRB) pada saluran paip keluli karbon dalam industri petroleum boleh menjejaskan kelancaran aliran pengangkutan minyak mentah dan meningkatkan kos pengoperasian. Usaha bagi melindungi keluli karbon serta pengawalan SRB masih memerlukan kajian yang berterusan. Dalam kajian ini, keberkesanan tetrametilamonium bromida (TMB), karboksimetil trimetilamonium (BTN) dan benzalkonium klorida (BKC) bagi melindungi keluli karbon di dalam persekitaran yang mengandungi SRB diuji melalui kaedah pengutuban elektrokimia dinamik (PED) dan morfologi keluli karbon dianalisis menggunakan mikroskop elektron imbasan. Analisis PED mendapati penggunaan TMB, BTN dan BKC masing-masing berupaya mengurangkan kadar kakisan sehingga 0.13, 0.56 dan 0.17 mm/thn berbanding 8.91 mm/thn pada larutan kawalan yang mengandungi SRB. Morfologi permukaan biofilem mengesahkan kadar pertumbuhan SRB serta hasilan metabolisme bakteria ini turut mengalami penyusutan. Kajian ini menunjukkan dua mekanisme kawalan kakisan didapati berlaku iaitu mekanisme perencatan kakisan melalui penjerapan sebatian amonium kuaterner pada permukaan keluli karbon serta berlakunya proses tindak balas mitigasi sebatian ini dengan bakteria SRB. Kesimpulannya, TMB, BTN dan BKC didapati berupaya melindungi keluli karbon daripada mengalami kakisan akibat aktiviti SRB.

Matched MeSH terms: Benzalkonium Compounds
Fulltext Novel Mangosteen-Leaves-Based Marker Ink: Color Lightness, Viscosity, Optimized Composition, and Microstructural Analysis

Mohd Basri MS, Liew Min Ren B, A Talib R, Zakaria R, Kamarudin SH

Polymers (Basel), 2021 May 14;13(10).
PMID: 34069259 DOI: 10.3390/polym13101581

Dry mangosteen leaves are one of the raw materials used to produce marker ink. However, research using this free and abundant resource is rather limited. The less efficient one-factor-at-a-time (OFAT) approach was mostly used in past studies on plant-based marker ink. The use of statistical analysis and the regression coefficient model (mathematical model) was considered essential in predicting the best combination of factors in formulating mangosteen leaf-based marker ink. Ideally, ink should have maximum color lightness, minimum viscosity, and fast-drying speed. The objective of this study to study the effect of glycerol and carboxymethyl cellulose (CMC) on the color lightness and viscosity of mangosteen-leaves-based marker ink. The viscosity, color lightness, and drying properties of the ink were tested, the significant effect of glycerol and CMC (responses) on ink properties was identified and the prediction model on the optimum value of the responses was developed by using response surface methodology (RSM). The microstructure of mangosteen leaves was analyzed to study the surface morphology and cell structure during dye extraction. A low amount of glycerol used was found to increase the value of color lightness. A decrease in CMC amounts resulted in low viscosity of marker ink. The optimum formulation for the ink can be achieved when the weight percents of glycerol, benzalkonium chloride, ferrous sulphate, and CMC are set at 5, 5, 1, and 3, respectively. SEM micrographs showed the greatest amount of cell wall structure collapse on samples boiled with the lowest amount of glycerol.

Matched MeSH terms: Benzalkonium Compounds
Fulltext Biocide susceptibilities and biofilm-forming capacities of Acinetobacter baumannii clinical isolates from Malaysia

Nor A'shimi MH, Alattraqchi AG, Mohd Rani F, A Rahman NI, Ismail S, Abdullah FH, et al.

J Infect Dev Ctries, 2019 07 31;13(7):626-633.
PMID: 32065820 DOI: 10.3855/jidc.11455

INTRODUCTION: Acinetobacter baumannii is a Gram-negative nosocomial pathogen that has the capacity to develop resistance to all classes of antimicrobial compounds. However, very little is known regarding its susceptibility to biocides (antiseptics and disinfectants) and capacity to form biofilms, particularly for Malaysian isolates.
AIM: To determine the susceptibility of A. baumannii isolates to commonly-used biocides, investigate their biofilm-forming capacities and the prevalence of biocide resistance and biofilm-associated genes.
METHODOLOGY: . The minimum inhibitory concentration (MIC) values of 100 A. baumannii hospital isolates from Terengganu, Malaysia, towards the biocides benzalkonium chloride (BZK), benzethonium chloride (BZT) and chlorhexidine digluconate (CLX), were determined by broth microdilution. The isolates were also examined for their ability to form biofilms in 96-well microplates. The prevalence of biocide resistance genes qacA, qacE and qacDE1 and the biofilm-associated genes bap and abaI were determined by polymerase chain reaction (PCR).
RESULTS: Majority of the A. baumannii isolates (43%) showed higher MIC values (> 50 µg/mL) for CLX than for BZK (5% for MIC > 50 µg/mL) and BZT (9% for MIC > 50 µg/mL). The qacDE1 gene was predominant (63%) followed by qacE (28%) whereas no isolate was found harbouring qacA. All isolates were positive for the bap and abaI genes although the biofilm-forming capacity varied among the isolates.
CONCLUSION: The Terengganu A. baumannii isolates showed higher prevalence of qacDE1 compared to qacE although no correlation was found with the biocides' MIC values. No correlation was also observed between the isolates' biofilm-forming capacity and the MIC values for the biocides.

Matched MeSH terms: Benzalkonium Compounds/pharmacology
Ocular Surface Disease in Glaucoma: Effect of Polypharmacy and Preservatives

Ramli N, Supramaniam G, Samsudin A, Juana A, Zahari M, Choo MM

Optom Vis Sci, 2015 Sep;92(9):e222-6.
PMID: 25730335 DOI: 10.1097/OPX.0000000000000542

PURPOSE: To evaluate the prevalence of ocular surface disease (OSD) in glaucoma and nonglaucoma subjects using different clinical tests and to determine the effect of number of antiglaucoma medications and preservatives on OSD.
METHODS: This is a cross-sectional, case-comparison study at the Eye Clinic of the University of Malaya Medical Centre, Malaysia, between June 2012 and January 2013. Glaucoma subjects (n = 105) using topical antiglaucoma medications were compared with control subjects (n = 102) who were not on any topical medications. The presence of OSD was assessed using the tear film breakup time (TBUT) test, corneal staining, Schirmer test, and Ocular Surface Disease Index (OSDI) questionnaire grading.
RESULTS: The prevalence of OSD varied from 37 to 91% in the glaucoma group, depending on the type of clinical test. More subjects in the glaucoma group had corneal staining (63% vs. 36%, p = 0.004), abnormal Schirmer tests (39% vs. 25%, p = 0.049), and moderate OSDI symptoms (17% vs. 7%, p = 0.028). The percentage with abnormal TBUT increased with higher numbers of topical medications and was high with both benzalkonium chloride-containing and preservative-free eye drops (90% and 94%, respectively, both p < 0.001). Benzalkonium chloride was associated with a nearly three times higher odds ratio of showing abnormal OSDI.
CONCLUSIONS: Ocular surface disease is common in those using topical antiglaucoma medications. Abnormal TBUT is associated with increasing number of eye drops and benzalkonium chloride-containing eye drops, although this also occurs with the use of preservative-free eye drops.
Study site: Eye Clinic, University of Malaya Medical Centre (UMMC), Kuala Lumpur, Malaysia,

Matched MeSH terms: Benzalkonium Compounds/adverse effects*
Methicillin-susceptible and -resistant Staphylococcus aureus with high-level antiseptic and low-level mupirocin resistance in Malaysia

Ghasemzadeh-Moghaddam H, van Belkum A, Hamat RA, van Wamel W, Neela V

Microb Drug Resist, 2014 Oct;20(5):472-7.
PMID: 24841796 DOI: 10.1089/mdr.2013.0222

The prevalence and spread of mupirocin and antiseptic resistance among colonizing and infectious Staphylococcus aureus were determined. S. aureus isolated from anterior nares and infection sites of patients hospitalized in the largest tertiary care referral hospital in Malaysia was investigated for mupirocin and antiseptic susceptibility testing, and for PCR detection of mupA, qacA/B, and smr genes. Twelve isolates showed resistance to mupirocin by disk diffusion, of which 10 (3.8%) harbored the mupA gene. Minimum inhibitory concentrations (MICs) ranged from 64 to 768 μg/ml for mupA positive and below 46 μg/ml for negative isolates. The mupA was more common among ST239 isolates (70%). The qacA/B was carried in 67 out of 95 methicillin-resistant Staphylococcus aureus (MRSA) (70.5%) and 3 out of 164 methicillin-susceptible Staphylococcus aureus (MSSA) (1.8%), while smr was carried in 6 out of 95 MRSA (6.3%) strains. MICs ranged from 3.9 to 15.6 μg/ml for benzethonium chloride (BTC) and benzalkonium chloride (BKC), and from 10.3 to 20.7 μg/ml for chlorhexidine digluconate (CHG). Isolates with qacA/B and smr or qacA/B alone showed higher MIC (20.7 μg/ml for CHG and 15.6 μg/ml for BTC and BKC) than the isolates that lacked antiseptic resistance genes (10.3 μg/ml for CHG and 3.9 μg/ml for BTC and BKC). In 16 cases, ST239 was isolated from the infection site and the nares simultaneously, and shared identical resistance patterns (qacAB or qacAB+smr), suggesting possible endogenous infection. Spread of low-level mupirocin resistance expressing ST239 MRSA and high-level resistance expressing emerging ST1, co-existing with antiseptic-resistant genes showing elevated MICs, should be monitored for effective infection control.

Matched MeSH terms: Benzalkonium Compounds/pharmacology
High prevalence of qacA/B carriage among clinical isolates of meticillin-resistant Staphylococcus aureus in Malaysia

Shamsudin MN, Alreshidi MA, Hamat RA, Alshrari AS, Atshan SS, Neela V

J Hosp Infect, 2012 Jul;81(3):206-8.
PMID: 22633074 DOI: 10.1016/j.jhin.2012.04.015

The minimum inhibitory concentrations (MICs) of 60 meticillin-resistant Staphylococcus aureus (MRSA) isolates from Malaysia to three antiseptic agents - benzalkonium chloride (BZT), benzethonium chloride (BAC) and chlorhexidine digluconate (CHG) - were determined. All isolates had MICs ranging from 0.5 to 2 mg/L. Antiseptic resistance genes qacA/B and smr were detected in 83.3% and 1.6% of the isolates, respectively. Carriage of qacA/B correlated with reduced susceptibility to CHG and BAC. This is the first report of the prevalence of qacA/B and smr gene carriage in Malaysian MRSA isolates, with a high frequency of qacA/B carriage. The presence of these antiseptic resistance genes and associated reduced susceptibility to antiseptic agents may have clinical implications.

Matched MeSH terms: Benzalkonium Compounds/pharmacology