title: Phenotypic and genetic characterization of multidrug-resistant Staphylococcus aureus in the tropics of Southeast Asia.
abstract: Antibiotic resistance has become a major public health problem throughout the world. The presence of antibiotic-resistant bacteria such as Staphylococcus aureus and antibiotic resistance genes (ARGs) in hospital wastewater is a cause for great concern today. In this study, 276 Staph. aureus isolates were recovered from hospital wastewater samples in Malaysia. All of the isolates were screened for susceptibility to nine different classes of antibiotics: ampicillin, ciprofloxacin, gentamicin, kanamycin, erythromycin, vancomycin, trimethoprim and sulfamethoxazole, chloramphenicol, tetracycline and nalidixic acid. Screening tests showed that 100 % of Staph.aureus isolates exhibited resistance against kanamycin, vancomycin, trimethoprim and sulfamethoxazole and nalidixic acid. Additionally, 91, 87, 50, 43, 11 and 8.7 % of isolates showed resistance against erythromycin, gentamicin, ciprofloxacin, ampicillin, chloramphenicol and tetracycline, respectively. Based on these results, 100 % of isolates demonstrated multidrug-resistant (MDR) characteristics, displaying resistance against more than three classes of antibiotics. Of 276 isolates, nine exhibited resistance to more than nine classes of tested antibiotics; these were selected for antibiotic susceptibility testing and examined for the presence of conserved ARGs. Interestingly, a high percentage of the selected MDR Staph.aureus isolates did not contain conserved ARGs. These results indicate that non-conserved MDR gene elements may have already spread into the environment in the tropics of Southeast Asia, and unique resistance mechanisms against several antibiotics may have evolved due to stable, moderate temperatures that support growth of bacteria throughout the year.
authors.affiliation: Department of Environmental Engineering and Green Technology, Malaysia-Japan International Institute of Technology, Universiti Teknologi Malaysia, Jalan Sultan Yahya Petra, 54100 Kuala Lumpur, Malaysia.
authors.forename: Siti Norayuni Mohd
authors.initials: SNM
authors.lastname: Zulkeflle
authors.affiliation: Department of Environmental Engineering and Green Technology, Malaysia-Japan International Institute of Technology, Universiti Teknologi Malaysia, Jalan Sultan Yahya Petra, 54100 Kuala Lumpur, Malaysia.
authors.forename: Yus Amira
authors.initials: YA
authors.lastname: Yusaimi
authors.affiliation: Department of Environmental Engineering and Green Technology, Malaysia-Japan International Institute of Technology, Universiti Teknologi Malaysia, Jalan Sultan Yahya Petra, 54100 Kuala Lumpur, Malaysia.|Graduate School of Life and Environmental Science, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan.
authors.forename: Norio
authors.initials: N
authors.lastname: Sugiura
authors.affiliation: Department of Environmental Engineering and Green Technology, Malaysia-Japan International Institute of Technology, Universiti Teknologi Malaysia, Jalan Sultan Yahya Petra, 54100 Kuala Lumpur, Malaysia.|Graduate School of Life and Environmental Science, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Iwamoto
authors.affiliation: Department of Environmental Engineering and Green Technology, Malaysia-Japan International Institute of Technology, Universiti Teknologi Malaysia, Jalan Sultan Yahya Petra, 54100 Kuala Lumpur, Malaysia.
authors.forename: Masafumi
authors.initials: M
authors.lastname: Goto
authors.affiliation: Graduate School of Life and Environmental Science, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan.
authors.forename: Motoo
authors.initials: M
authors.lastname: Utsumi
authors.affiliation: Department of Mechanical Precision Engineering, Malaysia-Japan International Institute of Technology, Universiti Teknologi Malaysia, Jalan Sultan Yahya Petra, 54100 Kuala Lumpur, Malaysia.
authors.forename: Nor'azizi Bin
authors.initials: NB
authors.lastname: Othman
authors.affiliation: Department of Environmental Engineering and Green Technology, Malaysia-Japan International Institute of Technology, Universiti Teknologi Malaysia, Jalan Sultan Yahya Petra, 54100 Kuala Lumpur, Malaysia.
authors.forename: Zuriati
authors.initials: Z
authors.lastname: Zakaria
authors.affiliation: Department of Environmental Engineering and Green Technology, Malaysia-Japan International Institute of Technology, Universiti Teknologi Malaysia, Jalan Sultan Yahya Petra, 54100 Kuala Lumpur, Malaysia.
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Hara
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001210:Asia, Southeastern; D002939:Ciprofloxacin / Q000494:pharmacology; D024901:Drug Resistance, Multiple, Bacterial; D005838:Genotype; D005839:Gentamicins / Q000494:pharmacology; D006761:Hospitals; D008826:Microbial Sensitivity Tests; D010641:Phenotype; D013211:Staphylococcus aureus / Q000145:classification / Q000187:drug effects* / Q000235:genetics* / Q000302:isolation & purification; D014640:Vancomycin / Q000494:pharmacology; D062065:Wastewater / Q000382:microbiology*
chemical_list: D000900:Anti-Bacterial Agents; D002939:Ciprofloxacin; D005839:Gentamicins; D014640:Vancomycin; D062065:Wastewater