The antimicrobial resistance is a global problem, probably due to the indiscriminate and irrational use of antibiotics, prescriptions for incorrect medicines or incorrect determinations of dose, route and/or duration. Another consideration is the uncertainty of patients receiving antibiotics about whether the quality of a generic medicine is equal to, greater than or less than its equivalent brand-name drug. The antibiotics behaviors must be evaluated in vitro and in vivo in order to confirm their suitability for therapeutic use.

Background: One of the most critical problems about antimicrobial therapy is the increasing resistance to antibiotics. Previous studies have shown that there is a direct relation between erroneous prescription, dosage, route, duration of the therapy and the antibiotics resistance. Other important point is the uncertainty about the quality of the prescribed medicines. Some physicians believe that generic drugs are not as effective as innovator ones, so it is very important to have evidence that shows that all commercialized drugs are suitable for therapeutic use. Methods: Microbial assays were used to establish the potency, the Minimal Inhibitory Concentrations (MICs), the Minimal Bactericidal Concentration (MBCs), the critical concentrations, and the production of spontaneous mutants that are resistant to vancomycin. Results: The microbial assay was validated in order to determine the Vancomycin potency of the tasted samples. All the products showed that have potency values between 90 - 115% (USP requirement). The products behave similarly because the MICs, The MBCs, the critical concentrations, the critical concentrations ratios between standard and samples, and the production of spontaneous mutants don't have significant differences. Conclusions: All products analyzed by microbiological tests, show that both trademarks and generics do not have statistical variability and the answer of antimicrobial activity Show also that they are pharmaceutical equivalents.

Resistance mechanisms occur in almost all clinical bacterial isolates and represent one of the most worrisome health problems worldwide. Bacteria can form biofilms and communicate through quorum sensing (QS), which allow them to develop resistance against conventional antibiotics. Thus, new therapeutic candidates are sought. We focus on alkylglycerols (AKGs) because of their recently discovered quorum sensing inhibition (QSI) ability and antibiofilm potential. Fifteen natural enantiopure AKGs were tested to determine their effect on the biofilm formation of other clinical bacterial isolates, two reference strains and their QSI was determined using Chromobacterium violaceum ATCC 12472. The highest biofilm inhibition rates (%) and minimum QS inhibitory concentration were determined by a microtiter plate assay and ciprofloxacin was used as the standard antibiotic. At subinhibitory concentrations, each AKG reduced biofilm formation in a concentration-dependent manner against seven bacterial isolates, with values up to 97.2%. Each AKG displayed QSI at different levels of ability without affecting the growth of C. violaceum. AKG (2S)-3-O-(cis-13’-docosenyl)-1,2-propanediol was the best QS inhibitor (20 μM), while (2S)-3-O-(cis-9’-hexadecenyl)-1,2-propanediol was the least effective (795 μM). The results showed for the first time the QSI activity of this natural AKG series and suggest that AKGs could be promising candidates for further studies on preventing antimicrobial resistance.

Introduction: Patients with febrile neutropenia (FN) exhibit changes in extracellular fluid that may alter the plasma concentrations of beta-lactams and result in therapeutic failure or toxicity. We evaluated the pharmacokinetics of piperacillin/tazobactam in patients with hematological malignancies and FN after receiving chemotherapy at a primary public cancer center. Methods: This was an open, nonrandomized, observational, descriptive, and prospective study. Samples from 15 patients with hematological malignancies and FN were evaluated after the administration of chemotherapy. Five blood samples were taken from each patient when the antibiotic level was at steady-state 10, 60, 120, 180, and 350 min after each dose. Antibiotic concentrations were measured using gel diffusion with Bacillus subtilis. All study participants provided written informed consent. Results: We investigated the pharmacokinetics of piperacillin in 14 patients between the ages of 18 years and 59 years and with a mean absolute neutrophil count of 208 cells per mm³ (standard deviation (SD) ± 603.2). The following pharmacokinetic measurements were obtained: maximum concentration, 94.1–1133 mg/L; minimum concentration, 0.47–37.65 mg/L; volume of distribution, 0.08–0.65 L/kg (mean, 0.34 L/kg); drug clearance (CL), 4.42–27.25 L/h (mean, 9.93 L/h); half-life (t_1/2), 0.55–2.65 h (mean, 1.38 h); and area under the curve, 115.12–827.16 mg · h/L. Conclusion: Patients with FN after receiving chemotherapy exhibited significant variations in the pharmacokinetic parameters of piperacillin compared with healthy individuals; specifically, FN patients demonstrated an increase in t_1/2 and decreased CL.

Patients with chemotherapy-induced febrile neutropenia (CIFN) may have changes in the pharmacokinetics (PK) compared to patients without malignancies or neutropenia. Those changes in antibiotic PK could lead to negative outcomes for patients if the therapy is not adequately adjusted to this. In this, open-label, non-randomized, prospective, observational, and descriptive study, a PK model of cefepime was developed for patients with hematological neoplasms and post-chemotherapy febrile neutropenia. This study was conducted at a cancer referral center, and study participants were receiving 2 g IV doses of cefepime every 8 h as 30-min infusions. Cefepime PK was well described by a two compartment model with a clearance dependent on a serum creatinine level. Using Monte Carlo simulations, it was shown that continuous infusions of 6g q24h could have a good achievement of PK/PD targets for MIC levels below the resistance cut-off point of Enterobacteriaceae. According to the simulations, it is unnecessary to increase the daily dose of cefepime (above 6 g daily) to increase the probability of target attainment (PTA). Cumulative fraction of response (CFR) using interment dosing was suboptimal for empirical therapy regimens against K. pneumoniae and P. aeruginosa, and continuous infusions could be used in this setting to maximize exposure. Patients with high serum creatinine levels were more likely to achieve predefined PK/PD targets than patients with low levels.

Previous research has determined that the required doses for treating febrile neutropenia with vancomycin are higher than the doses used conventionally. These recommendations have been made considering pharmacotherapeutic goals based on minimum concentration (${\mathrm{C}}_{\min }$) between 15–20 $\mathrm{mg}/\mathrm{L}$. This study was developed to evaluate dose recommendations based on the achievement of a target consisting of ratio of area under the curve over minimum inhibitory concentration (${\mathrm{AUC}}_{24\mathrm{h}}/\mathrm{MIC}$) $\ge 400$ in this population of individuals. This study was conducted in a referral hospital for cancer treatment, study participants received vancomycin doses of $1\mathrm{g}$ every 12 h in 2-4-h infusions. Vancomycin was described by a two-compartment pharmacokinetic model with clearance dependent on the estimated glomerular filtration rate. Simulations were performed taking into account a reduced version of the model to establish the influence of controllable and non-controllable variables on the probability of achieving several PK-PD targets. A dose of $2.5\mathrm{g}/\mathrm{day}$ in patients with estimated glomerular filtration rate ($\mathrm{eGFR}$) between 80 and $122\mathrm{mL}/\min /1.73{\mathrm{m}}^2$ was adequate to achieve the pharmacotherapeutic target. A discrepancy was found between $\mathrm{AUC}$-based and ${\mathrm{C}}_{\min }$-based PK/PD indices, the former being affected by the dose and creatinine clearance while the latter highly influenced by the interval between doses.