Single-dose pharmacokinetics of temocillin in plasma and soft tissues of healthy volunteers after intravenous and subcutaneous administration: a randomized crossover microdialysis trial.

BACKGROUND: The antibiotic temocillin has recently been rediscovered as a promising therapeutic option against MDR Gram-negative bacteria. However, some aspects of the pharmacokinetic (PK) profile of the drug are still to be elucidated: subcutaneous administration of temocillin might be of interest as an alternative to the intravenous route in selected patients. Similarly, information on the penetration of temocillin into human soft tissues is lacking. OBJECTIVES: To investigate the feasibility and plasma PK of subcutaneous dosing as well as soft tissue PK of temocillin after intravenous administration to healthy volunteers. METHODS: Eight healthy volunteers received 2 g of temocillin both as intravenous and subcutaneous infusion in a randomized two-period crossover study. Concentration-time profiles of total temocillin in plasma (after both routes) and of unbound temocillin in plasma, muscle and subcutis (only after intravenous dosing) were determined up to 12 h post-dose. RESULTS: Subcutaneous dosing caused some infusion site discomfort but resulted in sustained drug concentrations over time with only slightly decreased overall exposure compared with intravenous dosing. Plasma protein binding of temocillin showed concentration-dependent behaviour and was higher than previously reported. Still, unbound drug concentrations in muscle and subcutis determined by microdialysis markedly exceeded those in plasma, suggesting good tissue penetration of temocillin. CONCLUSIONS: The subcutaneous administration of temocillin is a valid and feasible alternative to intravenous dosing. With the description of plasma protein binding and soft tissue PK of temocillin in healthy volunteers, this study provides important information that adds to the ongoing characterization of the PK profile of temocillin and might serve as input for PK/PD considerations.

Activity of temocillin and comparators against urinary Escherichia coli and Klebsiella pneumoniae from Iran.

To evaluate the ground susceptibility of urinary Escherichia coli and Klebsiella pneumoniae to temocillin, the susceptibility of temocillin and comparators against 500 clinical isolates (231 E. coli and 269 K. pneumoniae) was tested. Temocillin was either found as the most active antibiotic (susceptibility rate of 92%) or the fourth most active antibiotic (65%), as per its urinary and systemic breakpoint, respectively. No difference of activity was observed in isolates expressing ESBL/AmpC enzymes. Considering the percentage of isolates expressing beta-lactamases and the need to spare broad-spectrum antibiotics, temocillin seems promising for treating urinary tract infections.

Activity of temocillin against ESBL-, AmpC-, and/or KPC-producing Enterobacterales isolated in Poland.

We evaluated the in vitro effectiveness of temocillin and several commonly used antimicrobials against Enterobacterales bacteria in isolates from Polish patients. We tested 400 isolates: 260 extended-spectrum ß-lactamase (ESBL)- and/or ampC ß-lactamase (AmpC)-producing isolates; 40 Klebsiella pneumoniae carbapenemase (KPC)-producing isolates; and 100 ESBL-, AmpC-, and KPC-negative isolates. The minimal inhibitory concentrations (MICs) of temocillin and 16 other antimicrobials were determined by reference microdilution. We also determined the activities of fosfomycin and ceftazidime/avibactam in KPC-producing isolates. The antibiotic sensitivities were interpreted according to EUCAST, BSAC, and CLSI criteria. Overall, 91% of the isolates were susceptible to temocillin using the urinary tract infection breakpoint (≤ 32 mg/L), and 61.8% were susceptible using the systemic infection breakpoint (≤ 8 mg/L). Meropenem and imipenem were the most active drugs (MIC50 values of 0.06 and 0.5 mg/L, respectively). Colistin and ertapenem (both MIC50 = 0.12 mg/L) were less active than meropenem or imipenem, but some strains were 77% susceptible to each of them. Among the KPC-producing isolates, 42.5% had MIC values of ≤ 32 mg/L (urinary tract infection breakpoint), but 100% were resistant to temocillin (systemic infection breakpoint). Ceftazidime/avibactam was active against 100% of the KPC-producing isolates, and fosfomycin was active against 40%. The empirical susceptibility rate observed among the urinary isolates suggests that temocillin may be considered as an alternative to carbapenems in the absence of KPC-producing bacteria. With regard to isolates from other sources, temocillin might be useful as a documented therapy agent or an empirical treatment in hospitals with a low prevalence of ESBL/AmpC-producing strains.

Activity of temocillin and 15 other agents, including fosfomycin and colistin, against Enterobacteriaceae in Hong Kong.

Limited data are available on temocillin susceptibilities in Enterobacteriaceae from Asian countries where antimicrobial resistance is prevalent. The in vitro activities of temocillin and 15 commonly used antimicrobials against 613 non-duplicate blood (n = 310) and urine (with clinically significant bacteriuria; n = 303) isolates of Enterobacteriaceae from patients who attended 3 out of 7 clusters of public hospitals of the Hospital Authority, Hong Kong, during 2015/2016 were tested. Minimum inhibitory concentrations (MICs) were determined by Clinical and Laboratory Standards Institute (CLSI) microbroth dilution (agar dilution with fosfomycin). For temocillin, MICs were also obtained using the British Society of Antimicrobial Chemotherapy (BSAC) microbroth dilution method and interpreted using the BSAC breakpoints. Overall, 93.0% (570) isolates were susceptible to temocillin using BSAC systemic breakpoint (≤8 mg/L) and all except 2 isolates were susceptible using the urinary breakpoint (≤32 mg/L). The extended spectrum beta-lactamase (ESBL) positivity rate was 23.2% (118 out of 508 E. coli, Klebsiella spp., Proteus spp.). Temocillin resistance rate to ESBL-positive isolates was 16.1% using the systemic breakpoint of ≤8 mg/L (MIC50 and MIC90 were 8 mg/L and 16 mg/L respectively). Two isolates (1 E. coli, temocillin MIC 64 mg/L, 1 Klebsiella sp., MIC 32 mg/mL) were resistant to meropenem and possessed the NDM-5 and KPC-2 genes respectively. Other susceptibility rates were: amoxicillin/clavulanate (59.1%), trimethoprim/sulfamethoxazole (62.5%), ciprofloxacin (71.5%), ceftriaxone (75.4%), nitrofurantoin (76.4%), gentamicin (78.3%), cefepime (81.1%), ceftazidime (83.5%), piperacillin/tazobactam (86%), colistin (88.8%), tigecycline (89.4%), fosfomycin (92.8%), ertapenem (99.0%), amikacin (99.2%) and meropenem (99.7%). Temocillin may be a useful alternative for the treatment of infections caused by ESBL and multi-drug-resistant Enterobacteriaceae in Hong Kong, particularly as resistance rates to ciprofloxacin, nitrofurantoin and piperacillin/tazobactam are high.

Temocillin (6 g daily) in critically ill patients: continuous infusion versus three times daily administration.

OBJECTIVES: The growing incidence of infections caused by Enterobacteriaceae producing ESBLs has led to increased use of carbapenems. Temocillin, which resists most ß-lactamases, may be a useful alternative. The aim of this study was to assess the pharmacokinetics and target attainment rates of 6 g of temocillin daily divided into three administrations every 8 h (three times daily) or administered by continuous infusion in critically ill patients. PATIENTS AND METHODS: This was a prospective, two-centre, randomized, controlled study in patients with intra-abdominal or lower respiratory tract infections caused by Enterobacteriaceae. RESULTS: Thirty-two patients were included and analysed for clinical efficacy, and pharmacokinetics were measured in 29 of them. Four patients undergoing continuous veno-venous haemofiltration (CVVH) were analysed separately. Mean, median and range of percentages of the dosing interval during which the free drug concentration remained >16 mg/L were 76.4, 98 and 18.7-98.9 in patients treated three times daily and 98.9, 89.7 and 36.4-99.9 in patients with continuous infusion, respectively. Clinical cure rates were 79% and 93% in each of these groups, respectively (not significant). Patients with CVVH received a daily dose of 750 mg given by continuous infusion and had a mean free drug concentration of only 13.8 ±â€Š1.9 mg/L. No adverse event attributable to temocillin was observed. CONCLUSIONS: Temocillin (6 g daily) given by continuous infusion allows a larger proportion of critically ill patients to have free drug serum concentrations covering infections caused by Enterobacteriaceae with an MIC of 16 mg/L compared with administration three times daily. Clinical efficacy compared with carbapenems in documented severe infections needs to be further studied.

Empirical use of temocillin in hospitalized patients: results from a retrospective audit.

Background: Following a global shortage of piperacillin/tazobactam in 2017, a formulary decision was taken at a large District General Hospital in the East of England to partly replace piperacillin/tazobactam with either temocillin as monotherapy or as part of a combination regimen. A retrospective audit was then conducted to assess the clinical effectiveness of temocillin therapy. Methods: Data from patients admitted to Watford General Hospital between May and August 2017 and treated with temocillin were reviewed retrospectively. Clinical characteristics of patients, data related to the episode of infection, clinical success, tolerance and mortality were analysed. Results: Temocillin was used in 126 patients with median age of 73 years. Infection episodes mostly originated from the abdomen (n = 46), the lung (n = 40) and the urinary tract (n = 21). Seventy-seven patients received temocillin as first-line therapy and 106 received it empirically, with temocillin prescribed in combination with another antibiotic in 82% of the empirically treated cases. Clinical success was observed in 88.9% of cases with no difference between patients treated empirically and others (89.6% versus 85%) or in efficacy among abdominal (91%), pulmonary (87.5%) and urinary (81%) infections. One case of Clostridioides difficile infection was reported in a patient treated with four different antibiotics. During the shortage period, the hospital's standardized mortality ratio was significantly lower when compared with the same period of the preceding year (85 versus 96). Conclusions: Using temocillin as part of an empirical strategy is feasible and safe as long as appropriate antibiotic combination is recommended based upon the indication and the likely bacterial pathogen.

Temocillin use in England: clinical and microbiological efficacies in infections caused by extended-spectrum and/or derepressed AmpC ß-lactamase-producing Enterobacteriaceae.

BACKGROUND: Temocillin, a ß-lactam stable against most ß-lactamases [including extended-spectrum ß-lactamases (ESBLs) and derepressed AmpC cephalosporinases (dAmpC)], has been suggested as an alternative to carbapenems when Pseudomonas can be excluded. Aims To assess temocillin clinical and microbiological cure rates (CCR and MCR) in infection caused by ESBL/dAmpC-producing Enterobacteriaceae and the effects of different dosage regimens. METHODS: Data were collected retrospectively from patients treated for at least 3 days with temocillin for urinary tract infection (n = 42), bloodstream infection (n = 42) or hospital-acquired pneumonia (n = 8) in six centres in the UK. RESULTS: Data on 92 infection episodes were collected. Overall CCR and MCR were 86% and 84% respectively; ESBL/dAmpC status had no effect. Significantly higher CCR and MCR occurred in patients treated with temocillin at optimal dosage [2 g twice daily or renally adjusted equivalent (ORAE)] compared with those treated with a suboptimal dosage (<2 g twice daily ORAE) (CCR 91% and MCR 92% versus CCR 73% and MCR 63%). This difference was more pronounced in the ESBL/dAmpC-positive subset (CCR 97% and MCR 97% versus CCR 67% and MCR 50%). CONCLUSIONS: Clinical and microbiological efficacies of temocillin are unaffected by ESBL/dAmpC production, confirming its potential application as a carbapenem-sparing agent. Both CCR and MCR are optimized by a regimen of 2 g twice daily ORAE in ESBL/dAmpC-positive infection.

Isolation and 2-D-DIGE proteomic analysis of intracellular and extracellular forms of Listeria monocytogenes.

The pathogenicity of Listeria monocytogenes is related to its ability of invading and multiplying in eukaryotic cells. Its main virulence factors are now well characterized, but limited proteomic data is available concerning its adaptation to the intracellular environment. In this study, L. monocytogenes EGD (serotype 1/2a) grown in human THP-1 monocytes (24 h) were successfully separated from host organelles and cytosolic proteins by differential and isopycnic centrifugation. For control, we used cell homogenates spiked with bacteria grown in broth. Proteomes from both forms of bacteria were compared using a 2-D-DIGE approach followed by MALDI-TOF analysis to identify proteins. From 1684 distinct spots, 448 were identified corresponding to 245 distinct proteins with no apparent contamination of host proteins. Amongst them, 61 show underexpression (stress defense; transport systems, carbon metabolism, pyrimidines synthesis, D-Ala-D-Ala ligase) and 22 an overexpression (enzymes involved in the synthesis of cell envelope lipids, glyceraldehyde-3-phosphate, pyruvate and fatty acids). Our proteomic analysis of intracellular L. monocytogenes (i) suggests that bacteria thrive in a more favorable environment than extracellularly, (ii) supports the concept of metabolic adaptation of bacteria to intracellular environment and (iii) may be at the basis of improved anti-Listeria therapy.

Contrasting effects of human THP-1 cell differentiation on levofloxacin and moxifloxacin intracellular accumulation and activity against Staphylococcus aureus and Listeria monocytogenes.

BACKGROUND AND AIMS: Listeria monocytogenes and Staphylococcus aureus invade and multiply in THP-1 monocytes. Fluoroquinolones accumulate in these cells, but are less active against intracellular than extracellular forms of L. monocytogenes and S. aureus. We examined whether differentiation of THP-1 monocytes into adherent, macrophage-like cells increases fluoroquinolone uptake and activity. METHODS: THP-1 monocytes were differentiated with phorbol myristate acetate (PMA) and compared with unstimulated cells for: (i) moxifloxacin and levofloxacin accumulation; and (ii) activity against phagocytosed L. monocytogenes and S. aureus (5 h contact). RESULTS: The differentiation of THP-1 monocytes caused: (i) a 3- to 4-fold increase in moxifloxacin uptake and a significant increase in its activity against intracellular L. monocytogenes (from 1.3 log(10) to 2.1 log(10) cfu decrease compared with the post-phagocytosis inoculum), but not against S. aureus (1.0-1.2 log(10) cfu decrease throughout); and (ii) no change in levofloxacin accumulation and intracellular activity against either L. monocytogenes or S. aureus. CONCLUSIONS: Although differentiation of monocytes enhances the uptake and activity of moxifloxacin against L. monocytogenes, this cannot be extended to other intracellular bacteria and to levofloxacin. These results further demonstrate that antibiotic intracellular accumulation and activity are not necessarily linked and suggest that intracellular drug and pathogen combinations must be studied individually.

Penicillin-binding proteins (PBP) and Lmo0441 (a PBP-like protein) play a role in Beta-lactam sensitivity of Listeria monocytogenes.

While seven penicillin-binding proteins (PBPs) or PBP-like proteins have been identified either by radiolabelled penicillin binding studies or genomic analysis, only PBP3 has been considered of interest for Beta-lactams activity against Listeria monocytogenes. Herein we reveal that both PBP4 and Lmo0441 (a PBP-like protein) play a direct role in cephalosporin activity in L. monocytogenes while PBP4 additionally has a protective affect against both penicillin and carbapenem.

Impairment of growth of Listeria monocytogenes in THP-1 macrophages by granulocyte macrophage colony-stimulating factor: release of tumor necrosis factor-alpha and nitric oxide.

BACKGROUND: Listeria monocytogenes tends to survive in phagocytes. Granulocyte macrophage colony-stimulating factor (GM-CSF) protects mice against L. monocytogenes infection, and mice knocked out for the GM-CSF gene are more susceptible to these infections. METHODS: THP-1 cells were used to characterize the GM-CSF receptor (binding isotherms; STAT5 phosphorylation), measure the intracellular growth of L. monocytogenes (5 h after phagocytosis), examine the influence of a 24-h incubation with GM-CSF before infection, measure the production of tumor necrosis factor (TNF)-alpha and the expression of nitric oxide synthase (iNOS), and evaluate the influence of anti-GM-CSF receptor (GM-CSFR alpha ) and anti-TNF-alpha antibodies and the addition of N(omega)-nitro-L-arginine methyl ester (L-NAME) and catalase. RESULTS: THP-1 cells display functional GM-CSFR alpha. GM-CSF impairs the intracellular growth of L. monocytogenes to approximately 65% of its value in unstimulated cells. This effect is abolished by anti-GM-CSFR alpha, anti-TNF-alpha antibodies, and catalase (and, to a lesser extent, by L-NAME). GM-CSF stimulates the release of TNF-alpha and the expression of iNOS. TNF-alpha added to unstimulated cells (even in large amounts) does not fully reproduce the impairment in the growth of L. monocytogenes caused by GM-CSF. CONCLUSIONS: GM-CSF impairs the intracellular growth of L. monocytogenes by a synergistic action of the GM-CSF-triggered release of autocrine TNF-alpha and hydrogen peroxide and the production of NO (associated with the stimulation of the expression of iNOS).