Browsing by Author "Tada, T"
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Publication Co-existence of aminoglycosides and β-lactam-resistant Escherichia coli phenotypes in a Tertiary care center of Nepal(Institute of Medicine, 2015) Shrestha, B; Tada, T; Shrestha, S; Katte, HPl; Ohara, H; Kirikae, T; Rijal, BP; Sherchand, JB; Pokhrel, BMAbstract Introduction: Multidrug-resistant Escherichia coli isolates conferring simultaneous resistance to both aminoglycosides and β-lactam drugs have serious implications for clinicians worldwide. This study was designed to evaluate the co-existence of various β-lactamases in aminoglycoside- resistant Escherichia coli amongst hospitalized subjects in a tertiary care center of Kathmandu, Nepal, between December 2013 and December 2014. Methods: Standard microbiological techniques were used for isolation and identification of the isolates. The antimicrobial susceptibility of bacterial isolates was determined following Clinical and Laboratory Standard Institute recommended Kirby-Bauer Disc Diffusion method. The defining criterion in this study for an isolate to be MDR, resistance to at least one agent in three or more than three different structural classes was taken. Results: Among 302 MDR E. coli isolates, 174 (58.0 %) were resistance to gentamicin and 138 (46.0 %) were resistance to amikacin. Maximum aminoglycoside-resistant 9/11(82.0%) strains were isolated from body fluids followed by 7/10 (70.0%) from bile, 6/9 (67.0%) from blood and 2/3 (67.0%) from tissue. Out of 174 aminoglycosides-resistant E. coli isolates, the simultaneous occurrence of Extended-spectrum- b- lactamase (ESBL) and AmpC β–lactamaseswas noted in 13.0 % isolates and Metallo-β-lactamase (MBL) and AmpC β–lactamasesin 8.0 % isolates. None E. coli isolates were positive for all 3 types of β–lactamases in combinations. In amikacin- resistant isolates, ESBL+ AmpC observed in 12% and MBL+AmpC seen in 10% isolates. Conclusion: Our results show a high frequency of aminoglycoside- resistance phenotypes. Strict application for appropriate use of antimicrobials in medical settings should be essential to minimize the emergence of multidrug-resistance among E. coli in hospitalized patients. Keywords: Aminoglycoside-resistant E. coli, Amp C β–lactamases, Metallo-β-lactamase, MDR E.coliPublication Phenotypic characterization of multidrug-resistant Acinetobacter baumannii with special reference to metallo-β-lactamase production from the hospitalized patients in a tertiary care hospital in Nepal(Institute of Medicine, 2015) Shrestha, S; Tada, T; Shrestha, B; Ohara, H; Kirikae, T; Rijal, BP; Pokhrel, BM; Sherchand, JBAbstract Introduction: Acinetobacter baumanniiis an important cause of nosocomial infection and has been associated with a wide variety of illnesses in hospitalized patients, especially patients in the intensive care units. The emergence of carbapenem-resistant clones of A. baumannii has been the most serious problem worldwide. After the carbapenem resistant clones have emerged, leaving the hope of treatment of A. baumannii infection is by the last resort of antibiotics such as tigecycline, polymyxin-B and colistin. The purpose of this study is to determine the antibiotic resistance patterns of A. baumannil isolates, prevalence of multidrug resistance, extended spectrum beta lactamase production and metallo-beta lactamase production. Methods: This is a prospective study conducted at the department of Clinical Microbiology. Tribhuvan University Teaching Hospital, from December 2013 to September 2014. Ethical approval was taken from the Institutional Review Board of Institute of Medicine. Two hundred and forty six Acinetobacterisolates were identified by standard microbiological testing. Antimicrobial susceptibility testing was performed by Kirby Bauer method as per the CLSI guidelines. Multidrug resistance was determined. ESBL production was detected by combination disc method and confirmed by Clinical and Laboratory Standerd Institute confirmatory test. MBL production was detected by using imipenem and imipenem/EDTA disc. Result: All 122 Multidrug-resistant A. baumannii isolateswere resistant to majority of the drugs used. All the isolates were completely sensitive to polymyxin B, colistin and tigecycline only. Fifteen (12.29%) isolates of A. baumannii were extended spectrum beta-lactamase producers and 50 (40.98%) were metallo-beta-lactamase producers. Multidrug resistance was common in A. baumannii Conclusion: Multidrug resistance in A. baumannii is becoming more common ESBL and MBL production should be promptly detected and reported to control the spread of resistant phenotypes to other individuals. Keywords: Acinetobacter baumannii, ESBL, MBL, multidrug-resistance