Isolasi bakteri resisten merkuri pada urin pasien dengan tumpatan amalgam di Puskesmas Tikala Baru

Mercury, a heavy metal, can be toxic to human body if it is exposed in high concentration. This metal has been used as dental amalgam fillings in dentistry since 150 years ago to reconstruct decayed teeth. Due to continuous exposure of mercury, bacteria inside human body have evolved mechanism of resistance toward higher form of mercury, due to the mer operon that has been charactherized in the plasmid. This study was aimed to find out whether there were mercury-resistant bacteria isolated from the urine of patients with dental amalgam fillings at Puskesmas (Primary health care) Tikala Baru, and identify the mercury-resistant bacteria. This was a descriptive exploratory study. Samples were mercury-resistant bacterial strains in the urine of patients with dental amalgam fillings who visited Puskesmas Tikala Baru. The results of mercury-resistant test showed that there were mercury-resistant bacteria in every concentrations. The morphological, physiological, and biochemical tests obtained 7 mercury-resistant bacterial genus, as follows: Streptococcus, Staphylococcus, Hafnia, Klebsiella, Enterobacter, Escherichia, and Bacillus. Conclusion: There were 7 genus of mercury-resistant bacteria which identified from urine of patient with dental amalgam fillings. Keywords: amalgam, mercury resistant bacteria. Abstrak: Merkuri merupakan suatu logam berat yang dapat bersifat toksik bila terpapar dengan tubuh manusia dalam konsentrasi tinggi. Penggunaan merkuri dalam amalgam telah digunakan dalam bidang kedokteran gigi selama hampir 150 tahun untuk merekonstruksi gigi berlubang. Akibat adanya paparan merkuri secara terus menerus, bakteri dalam tubuh manusia telah mengevolusi mekanisme resisten terhadap bentuk merkuri yang lebih tinggi di lingkungan, disebabkan oleh mer operon yang terkandung dalam plasmid. Penelitian ini bertujuan untuk mengetahui apakah terdapat bakteri resisten merkuri yang diisolasi dari urin pasien dengan tambalan merkuri di Puskesmas Tikala Baru, serta mengidentifikasi jenis dari bakteri resisten merkuri tersebut. Jenis penelitian ialah deskriptif eksploratif. Sampel yang digunakan ialah koloni bakteri yang resisten terhadap merkuri, yang terdapat dalam urin pasien dengan amalgam yang berkunjung ke Puskesmas Tikala Baru. Dari hasil uji resistensi merkuri, terdapat bakteri resisten merkuri pada setiap konsentrasi. Setelah dilakukan uji morfologi, fisiologi, dan biokimia didapatkan 7 genus bakteri yang resisten terhadap merkuri, yaitu Streptococcus, Staphylococcus, Hafnia, Klebsiella, Enterobacter, Escherichia, dan Bacillus. Simpulan: Terdapat 7 genus bakteri resisten merkuri yang teridentifikasi dalam urin pasien dengan tumpatan amalgam di Puskesmas Tikala Baru. Kata kunci: amalgam, bakteri resisten merkuri

UJI RESISTENSI BAKTERI BACILLUS SP YANG DIISOLASI DARI PLAK GIGI TERHADAP MERKURI DAN ERITROMISIN

Mercury is a toxic heavy metal that is used for dental fillings in the form of amalgam. To reduce the toxic effects produced by mercury, mercury resistant bacteria can be used. Bacillus sp is a gram-positive bacteria that is resistant to mercury. Besides having the mer operon genes that can transform Hg2+ to Hg0 that is less toxic, Bacillus sp bacteria also produce esterase that cause these bacteria resistant to erythromycin antibiotic. Erythromycin is a macrolide class of antibiotic used for the treatment of diseases caused by Gram-positive bacteria, especially Staphylococcus and Diphtheroids. To determine the resistance of Bacillus sp bacteria against mercury and erythromycin antibiotic. This study used a descriptive exploratory method with samples of bacteria and mercury are already available in the Laboratory of Pharmaceutical Microbiology. Based on the research that has been conducted, showed that the Bacillus sp bacteria is resistant to mercury and erythromycin.Keywords: bacteria, bacillus sp, resistant, mercury, erythromycinAbstrak: Merkuri merupakan logam berat bersifat toksik yang digunakan untuk penambalan gigi dalam bentuk amalgam. Untuk mengurangi efek toksik yang dihasilkan oleh merkuri, dapat digunakan bakteri resisten merkuri. Bakteri Bacillus sp merupakan bakteri gram positif yang resisten terhadap merkuri. Selain memiliki gen mer operon yang dapat mengubah Hg2+ menjadi Hg0 yang kurang toksik, bakteri Bacillus sp juga membentuk esterase yang menyebabkan terjadinya resisten bakteri ini terhadap antibiotik eritromisin. Eritromisin adalah antibiotik golongan makrolid yang digunakan untuk pengobatan penyakit akibat bakteri Gram positif khususnya Staphylococcus dan Diphtheroids. Untuk mengetahui resistensi bakteri Bacillus sp terhadap merkuri dan antibiotik eritromisin. Penelitian ini menggunakan metode deskriptif eksploratif dengan sampel bakteri dan merkuri yang sudah tersedia di Laboratorium Mikrobiologi Farmasi. Berdasarkan hasil penelitian yang telah dilakukan, diperoleh bahwa bakteri Bacillus sp resisten terhadap merkuri dan eritromisin.Kata Kunci: bakteri, bacillus sp, resisten, merkuri, eritromisin

The organomercurial lyase Merb possesses unique metal-binding properties

Select bacterial strains survive in mercury-contaminated environments due to acquisition of a transferable genetic element known as the mer operon. The mer operon typically encodes for a series of proteins that includes two enzymes, MerA and MerB. The organomercurial lyase (MerB) cleaves carbon-mercury bonds of organomercurial compounds yielding ionic mercury Hg (II) and a reduced-carbon compound. The Hg (II) ion product remains bounds until it is shuttled directly to the mercuric ion reductase (MerA) to be reduced. Based on NMR spectroscopy and X-ray crystallography studies1, we have determined that Cys96, Asp99 and Cys159 of E. Coli MerB form a catalytic triad required for cleavage of the carbon-Hg bond and binding of the Hg (II) ion product. The three catalytic residues are conserved in 61 of 65 known variants of MerB and the four remaining variants retain both cysteine residues, but contain a serine in place of Asp99. Given its unique activity, we have examined the role of serine as a catalytic residue and the ability of MerB to cleave other organometals such as organotin (known substrates or inhibitors) and organolead compounds. Soaking MerB crystals with either dimethyltindibromide or trimethylleadchloride compound indicates that MerB crystals have the capacity to cleave both carbon-Sn and carbon-Pb bonds, and we have determined crystal structures of a MerB-Sn and a MerB-Pb complex. Furthermore, substitution of Ser for Asp99 (MerB D99S) in E. coli MerB alters the metal-binding specificity, as MerB D99S chelated an unknown metal during its purification. X-ray crystallography, ICP-MS and electron paramagnetic resonance (EPR) studies were performed to identify the unknown metal and the results of these studies will be presented. Given that mercury contaminated sites are often contaminated with other heavy metals, these studies indicate that other heavy metals may have important implications when using MerA and MerB in bioremediation of organomercurial compounds.