In-vitro activity of piperacillin/tazobactam relative to other antibiotics against blood culture isolates

M Cormican, G Corbett-Feeney, S Kelly, D Hughes, J Flynn, R N Jones
Irish Journal of Medical Science 1998, 167 (3): 155-9
Resistance of bacteria to antibiotics is an increasing problem in many countries. Accurate locally relevant information is essential for detection and control of emerging resistance and to facilitate choice of empirical antibiotic therapy in the immediate management of seriously ill patients. We have determined the minimum inhibitory concentration of piperacillin/tazobactam for 97 strains of bacteria (55 Enterobacteriaceae, 13 non-fermentative Gram-negative bacilli, 22 Staphylococcus aureus, 6 Enterococcus faecalis and 1 Bacillus cereus) isolated from blood cultures and compared its activity to that of amoxycillin, co-amoxiclav, cephalothin, cefotaxime, ceftazidime, ciprofloxacin, gentamicin, piperacillin, cefotaxime. The strains were consecutive non-fastidious isolates with the following qualifications: coagulase negative staphylococci and diphtheroids were excluded and the number of Staphylococcus aureus isolates was limited to 12 methicillin-resistant and 10 methicillin-sensitive strains. Multiple isolates of the same species from individual patients were not included. The minimum inhibition concentrations of methicillin, penicillin, teichoplanin and vancomycin were also determined for specific groups of organisms. MICs were determined by the Etest method (AB Biodisk, Solna, Sweden) on Mueller Hinton agar. The MICs of appropriate American Type Culture Collection control strains were determined. Based on the interpretative criteria of the National Committee for Clinical Laboratory Standards (USA), 87 per cent of Gram-negative bacilli were susceptible to piperacillin/tazobactam compared with amoxycillin 26 per cent, cephalothin 35 per cent, co-amoxiclav 54 per cent, piperacillin 56 per cent, cefotaxime 69 per cent, ceftazidime 84 per cent, gentamicin 85 per cent and ciprofloxacin 91 per cent. Of all isolates 75 per cent were sensitive to piperacillin/tazobactam, compared with amoxycillin 22 per cent, cephalothin 35 per cent, piperacillin 41 per cent, co-amoxiclav 52 per cent, cefotaxime 59 per cent, ceftazidime 60 per cent, gentamicin 74 per cent and ciprofloxacin 77 per cent. Two isolates (1 E. coli and 1 Klebsiella pneumoniae) with antibiograms consistent with the relatively new resistance phenomenon of extended spectrum beta-lactamase production were identified. The spectrum of activity of piperacillin-tazobactam for empirical antibiotic therapy is significantly greater than that of piperacillin alone and is similar to that of ciprofloxacin and gentamicin.

Full Text Links

Find Full Text Links for this Article


You are not logged in. Sign Up or Log In to join the discussion.

Trending Papers

Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"