Efficacy of piperacillin-tazobactam and cefotaxime against Escherichia coli hyperproducing TEM-1 in a mouse peritonitis infection model.

OBJECTIVES: Piperacillin-tazobactam (TZP) is a frequently prescribed antibiotic in hospital settings. Reports suggest in vivo efficacy of TZP, despite in vitro resistance of isolates susceptible to cephalosporins. Escherichia coli (E. coli) isolates hyperproducing TEM-1 ß-lactamase possess this phenotype. This study investigated the influence of tazobactam (TAZ) concentration on piperacillin (PIP) inhibition of such isolates and compared the in vivo efficacy of TZP with cefotaxime (CTX) in an infection model. METHODS: The PIP MICs for E. coli isolates, either hyperproducing TEM-1 because of promoter substitutions (n = 4) or because of gene amplification (n = 2) or producing an inhibitor-resistant TEM-35 (IRT) (n = 1), were determined using increasing concentrations of TAZ in a checkerboard setup. Furthermore, the efficacy of TZP and CTX against the isolates was investigated in a mouse peritonitis model using antibiotic exposures mimicking human conditions. Isolates producing either OXA-48 or CTX-M-15 ß-lactamases were included as controls. RESULTS: Using TAZ concentrations ≤ 64 mg/L, one isolate hyperproducing TEM-1 had a PIP MIC of 8 at TAZ 16 mg/L and two additional isolates at TAZ 64 mg/L. In the mouse peritonitis infection model, reduction of bacterial load in the peritoneum was larger for TZP than CTX only for the CTX-M-15-producing isolate. Larger reductions in bacterial load were observed after CTX treatment than TZP treatment for seven of the eight remaining test isolates. CONCLUSIONS: Piperacillin-tazobactam treatment of E. coli isolates hyperproducing TEM-1 was less effective than CTX treatment and may, for some isolates, be comparable with TZP treatment of isolates producing established resistance markers as IRT or OXA-48.

Pharmacokinetics and Pharmacodynamics of High-Dose Piperacillin-Tazobactam in Obese Patients.

BACKGROUND AND OBJECTIVE: Standard piperacillin-tazobactam (P-T) dosing may be suboptimal in obesity, but high-dose regimens have not been studied. We prospectively evaluated the pharmacokinetics and pharmacodynamics of standard- and high-dose P-T in obese adult inpatients. METHODS: Those receiving standard-dose P-T with BMI ≥ 30 kg/m2 weighing 105-139 kg or ≥ 140 kg were given up to 6.75 g or 9 g every 6 h, respectively. Patients were monitored closely for safety. Elimination phase blood samples were drawn for 28 patients on standard and high doses to calculate the pharmacokinetic values using a one-compartment model. The likelihood of pharmacodynamic target attainment (100% fT > 16/4 mg/L) on various P-T regimens was calculated using each patient's own pharmacokinetic values. RESULTS: Piperacillin and tazobactam half-lives ranged from 0.5-10.6 to 0.9-15.0 h, while volumes of distribution ranged from 13.6-54.8 to 11.5-60.1 L, respectively. Predicted dose requirements for target attainment ranged from 2.25 g every 6 h in hemodialysis patients to a 27 g/24-h continuous infusion in a patient with a short P-T half-life. An amount of 4.5 g every 6 h would have met the target for only 1/12 (8%) patients with creatinine clearance ≥ 80 mL/min and 13/28 (46%) for all enrolled patients. One patient (3%) experienced an adverse event deemed probably related to high-dose P-T. CONCLUSION: Some patients required high P-T doses for target attainment, but dosing requirements were highly variable. Doses up to 6.75 g or 9 g every 6 h may be tolerable; however, studies are needed to see if high dosing, prolonged infusions, or real-time therapeutic drug monitoring improves outcomes in obese patients. CLINICAL TRIAL REGISTRATION (CLINICALTRIALS.GOV): NCT01923363.

Prospective evaluating the appropriate use of piperacillin /tazobactam in cardiac center of a tertiary care hospital.

BACKGROUND: The appropriate use of Piperacillin/Tazobactam (Pip/Taz), including the correct dose, escalating and or de-escalation according to the microbiological culture is essential to reduce the antibiotic resistance. Resistant to antimicrobials in a major global problem and contributes significantly to morbidity, mortality and cost of care. Guidelines exists to ensure appropriate use of Pip/Taz. Antibiotics Stewardship guidelines (https://apps.who.int/iris/bitstream/handle/10665/329404/9789241515481-eng.pdf) provides a detailed recommendation with regards to initiation, monitoring and escalation and de-escalation based on final culture results. Appling such guidelines ensures a more proper utilization of the empiric uses of antibiotics used in the hospital-based setting. Use of Pip/Taz in cases of suspected infection postoperatively is common practice in the cardiac surgery ward where this study was conducted. METHODS: This was a prospective cohort study involving all patients who were admitted to the cardiac surgery unit of a tertiary care center. All patient prescribed at least 1 day of Pip/Taz as an empirical therapy were included and prospectively observed. We aimed to evaluate the use of Pip/Taz and its appropriateness based on Antibiotics Stewardship guidelines (ASG). Any deviation from the guidelines in initiation, escalation, de-escalation based on culture and sensitivity results was considered inappropriate use. Four patients died (1.3%) early as result of complications for surgery but included in the analysis. The study was conducted from October 2017 to October 2018. RESULTS: Of the 300 patients who received Pip/Taz Cultures were done in 250 patients (83%). The overall appropriate use of Pip/Taz was seen in 166 patients (55.3%). CONCLUSION: The empirical use of Pip/Taz in the surgical cardiac unit was largely inappropriate and not entirely driven by the culture test results. Interventions are needed to optimize the use of Pip/Taz including appropriate culture and sensitivity driven use and timely de-escalation or de-escalation when indicated. This will prevent emergence of resistance and reduce the patient toxicity and financial costs.

Antimicrobial utilization and antimicrobial resistance in patients with haematological malignancies in Japan: a multi-centre cross-sectional study.

BACKGROUND: Infection is a major complication for patients with haematological malignancies. It is important to better understand the use of antimicrobial agents and antibiotic resistance for appropriate treatment and prevention of drug resistance. However, very few multi-centre analyses have focused on the use of antimicrobial agents and antibiotic resistance have been carried out in Japan. This study aimed to describe the characteristics of the use of antimicrobial agents and antibiotic resistance in patients with haematological malignancies. METHODS: We conducted a cross-sectional study using administrative claims data and antimicrobial susceptibility data in Japan. We included patients diagnosed with haematological malignancies, who were hospitalized in a haematology ward between 1 April 2015 and 30 September 2017 in 37 hospitals. Descriptive statistics were used to summarize patient characteristics, antimicrobial utilization, bacterial infections, and antibiotic resistance. RESULTS: In total, 8064 patients were included. Non-Hodgkin lymphoma (50.0%) was the most common malignancy. The broad-spectrum antibiotics displayed a following antimicrobial use density (AUD): cefepime (156.7), carbapenems (104.8), and piperacillin/tazobactam (28.4). In particular, patients with lymphoid leukaemia, myeloid leukaemia, or myelodysplastic syndromes presented a higher AUD than those with Hodgkin lymphoma, non-Hodgkin lymphoma, or multiple myeloma. The most frequent bacterial species in our study cohort was Escherichia coli (9.4%), and this trend was also observed in blood specimens. Fluoroquinolone-resistant E. coli (3.6%) was the most frequently observed antibiotic-resistant strain, while other antibiotic-resistant strains were rare. CONCLUSIONS: Broad-spectrum antibiotics were common in patients with haematological malignancies in Japan; however, antibiotic-resistant bacteria including carbapenem-resistant or multidrug-resistant bacteria were infrequent. Our results provide nationwide, cross-sectional insight into the use of antimicrobial agents, prevalence of bacteria, and antibiotic resistance, demonstrating differences in antimicrobial utilization among different haematological diseases.

Evaluation of pharmacokinetic/pharmacodynamic and clinical outcomes with 6-hourly empiric piperacillin-tazobactam dosing in hematological malignancy patients with febrile neutropenia.

BACKGROUND: Piperacillin-tazobactam is commonly used in neutropenic sepsis at standard doses that do not account for inter-individual differences in age, bodyweight and renal function. This study was designed to assess the rate of attainment of pharmacokinetic/pharmacodynamic (PK/PD) targets in patients receiving piperacillin/tazobactam therapy and to evaluate the effect on clinical outcomes. METHODS: Patients undergoing intensive chemotherapy for aggressive hematological malignancies were enrolled and treated with piperacillin/tazobactam 4 g/0.5 g every 6 h as initial antimicrobial therapy for first fever. Plasma drug concentrations were assayed at 50% and 100% of the dosing interval and compared with target MIC breakpoint of 16 mg/L to calculate the primary endpoints of 50% and 100% time above MIC (fT > MIC), respectively. Secondary endpoints included time to clinical cure, length of hospital stay, duration of antibiotics, and clinical treatment success. RESULTS: Fifty-eight percent (14/24) of patients achieved 50% fT > MIC while only 4% (1/24) achieved 100% fT > MIC. Higher creatinine clearance was significantly associated with lower trough drug concentration and appeared to be the dominant reason for the poor PK/PD target attainment. Median time to clinical cure, duration of antibiotic therapy, and hospital length of stay was 3, 13 and 21 days, respectively. There were no statistically significant differences in these outcomes between patients who did and did not achieve 100% fT > MIC. CONCLUSIONS: A significant majority of febrile neutropenic patients fail to achieve PK/PD targets with 6-hourly piperacillin dosing, although the clinical implications of this finding are unclear. Larger studies are needed to assess any impact on morbidity and mortality. This trial is registered on the ANZCTR (ACTRN12618000110280).

Phylogenetic analysis of resistance to ceftazidime/avibactam, ceftolozane/tazobactam and carbapenems in piperacillin/tazobactam-resistant Pseudomonas aeruginosa from cystic fibrosis patients.

Pseudomonas aeruginosa is one of the most important pathogens in cystic fibrosis. This study was conducted to analyse the genetic basis and phylogenetic profile of resistance to ceftazidime/avibactam, ceftolozane/tazobactam and carbapenems in cystic fibrosis P. aeruginosa isolates. Whole genome sequence analysis was conducted of isolates resistant to piperacillin/tazobactam collected from seven hospitals in Scotland since the introduction of these two cephalosporin/ß-lactamase inhibitor combinations. Ceftazidime resistance was primarily related to AmpC induction, as tested by cloxacillin inhibition assays, while high-level ceftazidime resistance not reversed by cloxacillin was associated with amino acid variations in AmpC. Only isolates resistant to both ceftazidime/avibactam and ceftolozane/tazobactam carried AmpD mutations, likely resulting in ampC overexpression. All isolates resistant to ceftazidime/avibactam and/or ceftolozane/tazobactam were resistant to carbapenems and showed inactivating mutations in the chromosomal oprD gene. None of the isolates bore class A, B, D plasmid-encoded carbapenemases. This study showed that mutational resistance emerged in phylogenetically distant lineages, which indicates the mutations occur independently without conferring a selective advantage to any phylogenetic lineage. These findings confirm the strong contribution of mutation-driven evolution to the population structure of P. aeruginosa.

Evaluation of a Carbapenem-Saving Strategy Using Empirical Combination Regimen of Piperacillin-Tazobactam and Amikacin in Hemato-Oncology Patients.

We implemented a carbapenem-saving strategy in hemato-oncology patients from 2013, using an empirical combination of piperacillin-tazobactam and amikacin for high-risk hemato-oncology patients with febrile neutropenia, who remain hemodynamically unstable > 72 hours despite initial cefepime treatment. All-cause mortality was not different between the two periods (6.54 and 6.57 deaths per 1,000 person-day, P = 0.926). Group 2 carbapenem use significantly decreased after strategy implementation (78.43 vs. 67.43 monthly days of therapy, P = 0.018), while carbapenem-resistant gram-negative bacilli did not show meaningful changes during the study period. Our carbapenem-saving strategy could effectively suppress carbapenem use without an increase of overall mortality.

Higher third-generation cephalosporin prescription proportion is associated with lower probability of reducing carbapenem use: a nationwide retrospective study.

Background: The ongoing extended spectrum ß-lactamase-producing Enterobacteriaceae (ESBL-PE) pandemic has led to an increasing carbapenem use, requiring release of guidelines for carbapenem usage in France in late 2010. We sought to determine factors associated with changes in carbapenem use in intensive care units (ICUs), medical and surgical wards between 2009 and 2013. Methods: This ward-level multicentre retrospective study was based on data from French antibiotic and multidrug-resistant bacteria surveillance networks in healthcare facilities. Antibiotic use was expressed in defined daily doses per 1000 patient-days. Factors associated with the reduction in carbapenem use (yes/no) over the study period were determined from random-effects logistic regression model (493 wards nested within 259 healthcare facilities): ward characteristics (type, size…), ward antibiotic use (initial antibiotic use [i.e., consumption of a given antibiotic in 2009], initial antibiotic prescribing profile [i.e., proportion of a given antibiotic in the overall antibiotic consumption in 2009] and reduction in the use of a given antibiotic between 2009 and 2013) and regional ESBL-PE incidence rate in acute care settings in 2011. Results: Over the study period, carbapenem consumption in ICUs (n = 85), medical (n = 227) and surgical wards (n = 181) was equal to 73.4, 6.2 and 5.4 defined daily doses per 1000 patient-days, respectively. Release of guidelines was followed by a significant decrease in carbapenem use within ICUs and medical wards, and a slowdown in use within surgical wards. The following factors were independently associated with a higher probability of reducing carbapenem use: location in Eastern France, higher initial carbapenem prescribing profile and reductions in consumption of fluoroquinolones, glycopeptides and piperacillin/tazobactam. In parallel, factors independently associated with a lower probability of reducing carbapenem use were ICUs, ward size increase, wards of cancer centres, higher initial third-generation cephalosporin (3GC) prescribing profile and location in high-risk regions for ESBL-PE. Conclusions: Our study suggests that a decrease in 3GCs in the overall antibiotic use and the continuation of reduction in fluoroquinolone use, could allow reducing carbapenem use, given the well-demonstrated role of 3GCs and fluoroquinolones in the occurrence of ESBL-PE. Thus, antibiotic stewardship programs should target wards with higher 3GC prescription proportions to reduce them.

Ocular Permeation of Topical Tazocin and Its Effectiveness in the Treatment of Pseudomonas aeruginosa Induced Keratitis in Rabbits.

PURPOSE: Pseudomonas aeruginosa is the most common causative organism for contact lens-associated corneal ulcer and is commonly treated with fluoroquinolones. With the emergence of resistant strains, it is important to investigate alternative therapies. Despite well-established efficacy of tazocin against systemic Pseudomonas infections, its topical use for the treatment of Pseudomonas keratitis has not been described, hence this study was aimed to find the ocular permeation of Tazocin and its efficacy in treating keratitis in rabbit eyes. METHODS: We investigated the ocular permeation of topical tazocin after single drop application in normal rabbit eyes by estimating piperacillin and tazobactam concentrations in cornea, aqueous, and vitreous using a validated LC-MS/MS method. Furthermore, we determined the efficacy of repeated dose administration of tazocin against experimentally induced P. aeruginosa keratitis in rabbits in comparison to moxifloxacin. To determine the efficacy, clinical examination, histopathological examination, and estimation of bacterial load and inflammatory cytokines in cornea were done. RESULTS: Significant corneal concentration of piperacillin and tazobactam was detected in normal rabbit corneas after single dose treatment with tazocin. In rabbits with Pseudomonas-induced keratitis, topical tazocin caused significant clinical and histopathological improvement. This improvement was associated with reduction in corneal bacterial load and inflammatory cytokines. Compared to moxifloxacin 0.5%, tazocin treated group showed greater clinical response which was associated with higher interleukin (IL)-1ß, lower tumor necrosis factor (TNF)-α, a comparable level of IL-8, greater reduction in corneal bacterial load, and lesser inflammatory cell infiltration. CONCLUSION: Tazocin showed good ocular penetration and was effective in treatment of Pseudomonas induced keratitis in rabbits.