aDepartment of Microbiology, Medical Faculty of Jenderal Soedirman University, Dr. Gumbreg, Medical Street, Mersi, Purwokerto, Central Java, Indonesia bDepartment of Microbiology, Medical Faculty of Gadjah Mada University, Farmako Street Sekip Utara, Sleman, Daerah Istimewa Yogyakarta, Indonesia cDepartement of Surgery, Medical Faculty of Diponegoro University-RSUP Dr.Kariadi, Dr Sutomo Street, No. 16, Semarang, Central Java, Indonesia