highly significantP < 0.001
Relative risk analysis of non-susceptibility to piperacillin/tazobactam across isolates from the three study sites revealed a highly significant association for OXA-1 ( P < 0.001), whereas no significant associations were observed for TEM-1 ( P = 0.424) or the combination of OXA-1 and TEM-1 ( P = 0.082).