IN VITRO EFFECT OF NEW ANTIBIOTICS AGAINST CLINICAL ISOLATES OF SALMONELLA PARATYPHI A
New Antibiotics Against Clinical Isolates of Salmonella Paratyphi A
Objective: The objective of this study was to determine in vitro MIC patterns of various therapeutic alternatives for the treatment of Salmonella Paratyphi A.
Study Design: Cross-sectional study.
Place and Duration of Study: Armed Forces Institute of Pathology Rawalpindi, from Jun 2012 to May 2014.
Material and Methods: Clinical samples were collected from suspected cases of salmonella infections. Culture was applied on Bactec 9050 special and/or standard media. Suspected Salmonella Paratyphi colonies were tested by API 20E and confirmed by serology. The isolates were also tested for resistance to ampicillin, cotrimoxazole, ciprofloxacin, ceftriaxone, doripenem, imipenem, ertapenem, aztreonam, moxifloxacin,cefpirome, cefepime,gatifloxacin, and chloramphenicol by Kirby-Bauer disc diffusion method. MIC (Minimum Inhibitory concentration)was done on MDR and ciprofloxacin intermediate or resistant cases by E-strips.
Results: One hundred and eleven isolates of Salmonella Paratyphi were recovered from 2230 specimens.
Resistance by disk diffusion technique noted in Salmonella Paratyphi A was ampicillin 60%, chloramphenicol
40%, cotrimoxazole 38%, ceftriaxone 7.9%, ciprofloxacin 8%, cefpodoxime 7.9%, imipenem and ertapenem 2.6%,aztreonam 1.3%, moxifloxacin 6.6%, and gatifloxacin 1.3%. No resistance was noted for doripenem and cefepime.MIC50 was 0.094 for Cefpirome, 0.125 Aztreonam, 0.25 imipenem and tigecycline, 2 cefpodoxime and 8 for azithromycin.
Conclusion: Azithromycin, Aztreonam, Imipenem, tygecycline, cefpodoxime and cefpirome are potential
therapeutic agents for resistant Salmonella Paratyphi A infections.
Keywords: Antibiotics, Resistance, Salmonella Paratyphi A.