Levofloxacin for the treatment of community-acquired pneumonia

Patterns of fluoroquinolone utilization and resistance in a tertiary care hospital: a retrospective cross-sectional analysis study from a developing country

BACKGROUND

Fluoroquinolones are the most commonly prescribed antibiotics. Because of their known tendency to drive antimicrobial resistance, their prescribing patterns need to be more restricted. This study aimed to describe the clinical practice of fluoroquinolone prescription, dose adjustments for renal impairment patients and bacterial resistance profiles, eventually providing evidence-based recommendations to optimize antibiotic prescribing practices in the local population.

METHODS

This retrospective, cross-sectional study was conducted at An-Najah National University Hospital in Palestine. The data were collected from admitted patients who were given ciprofloxacin or levofloxacin from July 2021 to June 2023. Data from 692 inpatients across various hospital departments were examined (409 for levofloxacin and 283 for ciprofloxacin). Statistical analysis was performed via IBM SPSS version 23.0 to summarize the demographic, clinical, and epidemiological data.

RESULTS

The sociodemographic profile revealed diverse age distributions, with 25.4% and 39% older than 50 years for ciprofloxacin and levofloxacin, respectively. Ciprofloxacin was predominantly used in the oncology department (28.2%), with surgical prophylaxis (22.6%) and febrile or afebrile neutropenia (21.1%) being the most common indications. Levofloxacin was predominantly used in the medical ward (45.7%), mainly for lower respiratory tract infection (58.8%) and prophylaxis for bone marrow transplantation (16.5%). Enterococcus and methicillin-resistant Staphylococcus aureus were the most commonly isolated pathogens, with 62.5% of the isolates demonstrating resistance to ciprofloxacin. Moreover, extended-spectrum beta-lactamase-producing Enterobacterales were the most common pathogen isolated, with 33.3% being resistant to levofloxacin. Statistical analysis revealed a significant association between the choice of antibiotic and the approach to therapy. Levofloxacin was significantly more likely than ciprofloxacin to be used as empiric therapy (p < 0.001), whereas ciprofloxacin was more likely to be used as targeted therapy (p < 0.001).

CONCLUSIONS

This study investigated prescribing practices and resistance to levofloxacin and ciprofloxacin in a large hospital in a developing country. According to the bacterial resistance profiles, we conclude that there is a need for hospital departments to exercise greater restraint on the use of these antibiotics. To this end, further studies addressing the clinical efficacy of fluoroquinolones against the current treatment guidelines to evaluate their appropriateness should be carried out.

Global evolutionary dynamics and resistome analysis of Clostridioides difficile ribotype 017

Clostridioides difficile PCR ribotype (RT) 017 ranks among the most successful strains of C. difficile in the world. In the past three decades, it has caused outbreaks on four continents, more than other ‘epidemic’ strains, but our understanding of the genomic epidemiology underpinning the spread of C. difficile RT 017 is limited. Here, we performed high-resolution phylogenomic and Bayesian evolutionary analyses on an updated and more representative dataset of 282 non-clonal C. difficile RT 017 isolates collected worldwide between 1981 and 2019. These analyses place an estimated time of global dissemination between 1953 and 1983 and identified the acquisition of the ermB-positive transposon Tn6194 as a key factor behind global emergence. This coincided with the introduction of clindamycin, a key inciter of C. difficile infection, into clinical practice in the 1960s. Based on the genomic data alone, the origin of C. difficile RT 017 could not be determined; however, geographical data and records of population movement suggest that C. difficile RT 017 had been moving between Asia and Europe since the Middle Ages and was later transported to North America around 1860 (95 % confidence interval: 1622–1954). A focused epidemiological study of 45 clinical C. difficile RT 017 genomes from a cluster in a tertiary hospital in Thailand revealed that the population consisted of two groups of multidrug-resistant (MDR) C. difficile RT 017 and a group of early, non-MDR C. difficile RT 017. The significant genomic diversity within each MDR group suggests that although they were all isolated from hospitalized patients, there was probably a reservoir of C. difficile RT 017 in the community that contributed to the spread of this pathogen.

Which Analysis Approach Is Adequate to Leverage Clinical Microdialysis Data? A Quantitative Comparison to Investigate Exposure and Reponse Exemplified by Levofloxacin

Purpose

Systematic comparison of analysis methods of clinical microdialysis data for impact on target-site drug exposure and response.

Methods

39 individuals received a 500 mg levofloxacin short-term infusion followed by 24-h dense sampling in plasma and microdialysate collection in interstitial space fluid (ISF). ISF concentrations were leveraged using non-compartmental (NCA) and compartmental analysis (CA) via (ii) relative recovery correction at midpoint of the collection interval (midpoint-NCA, midpoint-CA) and (ii) dialysate-based integrals of time (integral-CA). Exposure and adequacy of community-acquired pneumonia (CAP) therapy via pharmacokinetic/pharmacodynamic target-attainment (PTA) analysis were compared between approaches.

Results

Individual AUC_ISF estimates strongly varied for midpoint-NCA and midpoint-CA (≥52.3%CV) versus integral-CA (≤32.9%CV) owing to separation of variability in PK parameters (midpoint-CA = 46.5%–143%CV_PK, integral-CA = 26.4%–72.6%CV_PK) from recovery-related variability only in integral-CA (41.0%–50.3%CV_recovery). This also led to increased variability of AUC_plasma for midpoint-CA (56.0%CV) versus midpoint-NCA and integral-CA (≤33.0%CV), and inaccuracy of predictive model performance of midpoint-CA in plasma (visual predictive check). PTA analysis translated into 33% of evaluated patient cases being at risk of incorrectly rejecting recommended dosing regimens at CAP-related epidemiological cut-off values.

Conclusions

Integral-CA proved most appropriate to characterise clinical pharmacokinetics- and microdialysis-related variability. Employing this knowledge will improve the understanding of drug target-site PK for therapeutic decision-making.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11095-021-02994-1.

Pharmacokinetics and pharmacodynamics of levofloxacin in bronchial mucosa and lung tissue of patients undergoing pulmonary operation

Levofloxacin is a major antimicrobial agent that is used for the treatment of community-acquired lower respiratory tract infections (LRTIs). The present study was designed to investigate the pharmacokinetics (PK) and pharmacodynamics (PD) of levofloxacin in bronchial mucosa and lung tissue. A total of 32 patients undergoing pulmonary surgery were randomly assigned to one of four groups (8 subjects/group). All patients received a single dose of 500 mg levofloxacin orally prior to the operation. Blood, lung tissue and bronchial mucosa samples were collected prior to treatment and at 1.5, 4, 8, 12 and 24 h following treatment. The drug concentration was determined and PK and PD profiles were calculated using MATLAB software. The peak concentration of levofloxacin was 7.0±1.2 µg/g in lung tissues and 9.4±2.1 µg/g in bronchial mucosa. The corresponding area under the curve between 0 and 24 h (AUC0-24) was 85.7±8.5 and 137.3±19.4 µg h/g. The mean permeability of levofloxacin (ratio of concentration in tissue to that in plasma) was 2.4 in lung tissue and 4.4 in the bronchial mucosa. The PK profiles of levofloxacin in the plasma, lung and bronchial mucosa were described using an integrated one-compartment model. The probability of fAUC0-24/minimal inhibitory concentration (MIC) target attainment of levofloxacin against Streptococcus pneumoniae in the lung and bronchial mucosa was maintained at 100% when MIC ≤1 mg/l, while the cumulative fraction of fAUC0-24/MIC in the corresponding tissues was 94.4 and 98.1%, respectively. The present study demonstrated the high permeability of levofloxacin in the lung and bronchial mucosa of patients undergoing pulmonary surgery. In conclusion, treatment using 500 mg levofloxacin exhibits good clinical and microbiological efficacy for use in LRTIs that are caused by S. pneumoniae. This trial was registered retrospectively in the Chinese Clinical Trial Registry on January 13, 2020 (registration no. ChiCTR2000029096).

In vitro Activities of Nemonoxacin and Other Antimicrobial Agents Against Human Mycoplasma and Ureaplasmas Isolates and Their Defined Resistance Mechanisms

Nemonoxacin, a newly developed non-fluorinated quinolone (NFQ), selectively inhibits bacterial DNA topoisomerase activity. However, its activities against Mycoplasmas have rarely been studied to date. Herein, the activities of nemonoxacin were evaluated against clinical isolates of 50 Mycoplasma pneumoniae, 20 Mycoplasma hominis, and 77 Ureaplasma spp., and they were compared to fluoroquinolones, tetracyclines, and macrolides. Nemonoxacin MICs (μg/ml) ranged from 0.03 to 0.25 for M. pneumoniae, 0.25 to 8 for M. hominis, and 0.06 to >16 for Ureaplasma spp., and all of the ranges are similar to those of fluoroquinolones. The activity of nemonoxacin against Mycoplasmas was not affected by resistance to macrolides in the strains tested, but it seems to have the same resistant mechanism as fluoroquinolones. In addition, minimum bactericidal concentrations (MBC) of nemonoxacin to M. pneumoniae were within two dilutions of the MIC values, indicating a bactericidal effect on M. pneumoniae. Nemonoxacin merits further study for treating infections caused by these organisms.

Pharmacokinetics and pharmacodynamics of levofloxacin injection in healthy Chinese volunteers and dosing regimen optimization

WHAT IS KNOWN AND OBJECTIVE

The pharmacokinetics (PK) and pharmacodynamics (PD) of levofloxacin were investigated following administration of levofloxacin injection in healthy Chinese volunteers for optimizing dosing regimen.

METHODS

The PK study included single-dose (750 mg/150 mL) and multiple-dose (750 mg/150 mL once daily for 7 days) phases. The concentration of levofloxacin in blood and urine was determined using HPLC method. Both non-compartmental and compartmental analyses were performed to estimate PK parameters. Taking fC(max) /MIC ≥5 and fAUC(24 h) /MIC ≥30 as a target, the cumulative fraction of response (CFR) of levofloxacin 750 mg for treatment of community-acquired pneumonia (CAP) was calculated using Monte Carlo simulation. The probability of target attainment (PTA) of levofloxacin at various minimal inhibitory concentrations (MICs) was also evaluated.

RESULTS AND DISCUSSION

The results of PK study showed that the C(max) and AUC(0-∞) of levofloxacin were 14·94 μg/mL and 80·14 μg h/mL following single-dose infusion of levofloxacin. The half-life and average cumulative urine excretion ratio within 72 h post-dosing were 7·75 h and 86·95%, respectively. The mean C(ss,max), C(ss,min) and AUC(0-τ) of levofloxacin at steady state following multiple doses were 13·31 μg/mL, 0·031 μg/mL and 103·7 μg h/mL, respectively. The accumulation coefficient was 1·22. PK/PD analysis revealed that the CFR value of levofloxacin 750-mg regimen against Streptococcus pneumoniae was 96·2% and 95·4%, respectively, in terms of fC(max) /MIC and fAUC/MIC targets.

WHAT IS NEW AND CONCLUSION

The regimen of 750-mg levofloxacin once daily provides a satisfactory PK/PD profile against the main pathogenic bacteria of CAP, which implies promising clinical and bacteriological efficacy for patients with CAP. A large-scale clinical study is warranted to confirm these results.