piperacillin-susceptible bacteria including Escherichia coli, Klebsiella pneumoniae and Staphylococcus aureus in two dosing regimes (4.5g every 8 hours and 3.375g every 8 hours). The evidence for this was obtained through Monte Carlo experiments procured by a special program (OPTAMA), where for several different scenarios (e.g. hospital acquired infections, secondary peritonitis, skin or soft tissue infections), the probability of attaining those figures were in the ranges of 85 - 95% and 90 - 89% respectively for the two regimes. In addition, two similar dosing regimes (3.375g and 4.5g every 6 hours) both had lower chances of reaching the 90% T>MIC threshold compared to the 50% threshold against hospital acquired pneumonia pathogens. The optimization of piperacillin-tazobactam drug efficiency has been covered by various studies, limiting the focus down to two types of infusions; continuous and intermittent. A comparison using the two administration methods under the same dosage regime of 13.5g per day highlighted no major differences when treating complex intra-abdominal infections. Furthermore, a follow-up analyzation of this trial deduced that both methods of administration lead to higher concentrations compared to the MIC of the pathogens that were used. Similar results are found in a study where a select number of β-lactam susceptible pathogens consisting of Enterococcus faecalis, Klebsiella pneumoniae and Citrobacter freundii were used to test a ~10g every 24 hour dosing interval for continuous infusion. Organisms with a piperacillin-tazobactam MIC values equal to 32 or less than 16ml/I lead to 50% T>MIC when extended-interval intermittent administrations under two different dosing intervals (8.1g and 6.75g every 12 hours) were used against them. The pharmacodynamic target attainments corresponding to pathogens with MIC values of 16 mg/I are found to reach 92% when a more traditional 4 hour dosing regime is utilized to administer at irregular intervals. One study using the Monte Carlo simulation produced contradicting results to the previous studies, deducing that inadequate pharmacodynamic targets were achieved (T>MIC > 50%) for similar ESBL-producing bacteria, applying to both continuous and high dosage intermittent infusion. Chemistry Derived from “the addition of a hydrophilic heterocyclic group to the α-amino group of ampicillin”, the structure consists of a thiazolidine ring conjoined to a β-lactam ring contained within several ring compounds. The addition of this substituent increases the compound's affinity to penicillin-binding protein PBP-3, improving activity against Gram-negative bacteria, and thus broadening its spectrum of activity. Susceptible β-lactamase producing bacteria such as Staphylococcus spp. or Haemophilus influenzae, the