Integrative population pharmacokinetic/pharmacodynamic analysis of nemonoxacin capsule in Chinese patients with community-acquired pneumonia.

Introduction: Nemonoxacin is an innovative quinolone antibiotic for treatment of community-acquired pneumonia (CAP). As more data are available from clinical studies, it is necessary to perform an integrative pharmacokinetic/pharmacodynamic (PK/PD) analysis to support and justify the optimal dosing regimen of nemonoxacin in clinical practice. Methods and Results: We developed a population PK model using non-linear mixed effect model based on the data of 195 Chinese subjects receiving nemonoxacin in phase I to III clinical trials. The base model was a standard two-compartment PK model defined by clearance (12 L/h) and central volume of distribution (86 L). Covariates included creatinine clearance (CLcr), body weight (BW), sex, disease status and food. Compared to the subject with BW 60 kg, Cmax and A U C 0 - 24 , ss reduced by 24% and 19% in the subject with BW 80 kg, respectively. Compared to the subject with CLcr 150 ml/min, A U C 0 - 24 , ss and T1/2 increased by 28% and 24%, respectively in the subject with CLcr 30 ml/min. Compared to the fasted status, Tmax of nemonoxacin increased by 1.2 h in the subject with fed status. Effects of sex and disease status on PK parameters were small (change of PK parameters ≤19%). AUC0-24/MIC and %T > MIC were identified as the optimal PK/PD indices for predicting clinical efficacy. The AUC0-24/MIC target was 63.3, 97.8, and 115.7 against Streptococcus pneumoniae, Staphylococcus aureus, and Haemophilus influenzae, respectively. The %T > MIC target was 7.96% against Klebsiella pneumoniae. Monte Carlo simulation showed that treatment with nemonoxacin 500 mg q24 h could attain a PK/PD cutoff value higher than the MIC90 against S. pneumoniae and S. aureus. The corresponding cumulative fraction of response (CFR) was greater than 93%, while nemonoxacin 750 mg q24 h would provide higher PK/PD cutoff value against Haemophilus parainfluenzae, and higher CFR (83%) than 500 mg q24 h. Conclusion: Integrative PK/PD analysis justifies the reliable clinical and microbiological efficacy of nemonoxacin 500 mg q24 h in treating CAP caused by S. pneumoniae, S. aureus, and K. pneumoniae, irrespective of patient sex, mild renal impairment, empty stomach or not. However, nemonoxacin 750 mg q24 h would provide better efficacy than 500 mg q24 h for the CAP caused by H. parainfluenzae in terms of CFR.

Safety of oral nemonoxacin: A systematic review of clinical trials and postmarketing surveillance.

Background: Postmarketing safety analysis is an effective supplement for new drugs in clinical practice. Therefore, we aimed to systematically assess the safety of oral nemonoxacin malate, the first approved C-8-methoxy non-fluorinated quinolone, in clinical studies and via postmarketing safety surveillance. Methods: We electronically and manually searched and screened safety data (including premarketing and postmarketing data) of oral nemonoxacin from clinical registries. We standardized and summarized the reported adverse events according to the Medical Dictionary for Regulatory Activities System Organ Class and Preferred Terms. We summarized and reported the number and frequency (%) of the AEs and serious AEs in patients with community-acquired pneumonia and in specific patients. Results: Three Phase II/III comparator studies (n = 670, nemonoxacin), one Phase IV study (n = 461), two special population pharmacokinetic studies (n = 40), four observational studies (n = 1,852), and one 5-year postmarketing surveillance project (n = 257,420) were included in this study. The Phase II/III studies showed that the commonly reported drug-related AEs were similar for oral 500 mg nemonoxacin and levofloxacin treatments, which mainly included increased alanine aminotransferase levels (4.4% vs. 2.5%), neutropenia (2.5% vs. 4.4%), nausea (2.5% vs. 1.6%), and leukopenia (2.3% vs. 3.2%). No drug-related deaths were reported. Postmarketing safety surveillance revealed that known adverse drug reaction characteristics were generally unchanged. Pharmacokinetic data suggested that dose adjustment was not necessary in elderly patients, which was confirmed by a Phase IV study in an elderly population, in patients with renal impairment with CLcr ≥50 ml/min, and in those with mild-to-moderate hepatic impairment. Conclusion: Clinical trial data of approximately 1,450 patients and postmarketing data of >257,420 patients suggest that nemonoxacin is generally well tolerated and can be a suitable alternative to fluoroquinolones for patients with CAP.

Prevalence and risk factors of trimethoprim/sulfamethoxazole-related acute kidney injury in pediatric patients: an observational study from a public database.

Background: Trimethoprim/sulfamethoxazole (TMP/SMZ) is widely used in various clinical settings. Studies have revealed that it may cause acute kidney injury (AKI) in adults. However, the correlation between the use of TMP/SMZ and renal injury in pediatric patients is still unclear. This study aimed to identify the impact of TMP/SMZ on the occurrence of AKI in children. Methods: A retrospective observational study was conducted using data of patients treated with TMP/SMZ from the Paediatric Intensive Care clinical database. A newly developed criterion was used for the diagnosis of AKI, and univariate and multiple logistic regression analyses were performed to identify the risk factors of TMP/SMZ-related renal injury. Results: A total of 113 patients were included. The prevalence of AKI was 21.2% (24/113). Univariate analysis indicated that the AKI group showed significantly higher baseline serum creatinine level (46.00 vs. 37.00 µmol/L; P=0.034) and in-hospital mortality rate [29.2% (7/24) vs. 9.0% (8/89); P=0.01] than that of the non-AKI group. Multivariate analysis revealed that the occurrence of AKI was significantly associated with increased baseline serum creatinine level [odds ratio (OR) =1.029; 95% CI: 1.006-1.053; P=0.014] and concurrent use of vancomycin (OR =5.349; 95% CI: 1.381-20.714; P=0.015). A proportion of 79.2% of patients (19/24) developed AKI within the first 10 days of TMP/SMZ use. Conclusions: Elevated baseline serum creatinine level (≥40.25 µmol/L) and concurrent use of vancomycin were associated with the development of AKI in young patients. Further large multi-center prospective studies are necessary to confirm these relationships and validate their clinical significance.

Simultaneous Detection of Pathogens and Tumors in Patients With Suspected Infections by Next-Generation Sequencing.

Background: Differential diagnosis of patients with suspected infections is particularly difficult, but necessary for prompt diagnosis and rational use of antibiotics. A substantial proportion of these patients have non-infectious diseases that include malignant tumors. This study aimed to explore the clinical value of metagenomic next-generation sequencing (mNGS) for tumor detection in patients with suspected infections. Methods: A multicenter, prospective case study involving patients diagnosed with suspected infections was conducted in four hospitals in Shanghai, China between July 2019 and January 2020. Based upon mNGS technologies and chromosomal copy number variation (CNV) analysis on abundant human genome, a new procedure named Onco-mNGS was established to simultaneously detect pathogens and malignant tumors in all of the collected samples from patients. Results: Of 140 patients screened by Onco-mNGS testing, 115 patients were diagnosed with infections; 17 had obvious abnormal CNV signals indicating malignant tumors that were confirmed clinically. The positive percent agreement and negative percent agreement of mNGS testing compared to clinical diagnosis was 53.0% (61/115) and 60% (15/25), vs. 20.9% (24/115) and 96.0% (24/25), respectively, for conventional microbiological testing (both P <0.01). Klebsiella pneumoniae (14.8%, 9/61) was the most common pathogen detected by mNGS, followed by Escherichia coli (11.5%, 7/61) and viruses (11.5%, 7/61). The chromosomal abnormalities of the 17 cases included genome-wide variations and local variations of a certain chromosome. Five of 17 patients had a final confirmed with malignant tumors, including three lung adenocarcinomas and two hematological tumors; one patient was highly suspected to have lymphoma; and 11 patients had a prior history of malignant tumor. Conclusion: This preliminary study demonstrates the feasibility and clinical value of using Onco-mNGS to simultaneously search for potential pathogens and malignant tumors in patients with suspected infections.

Predictors of mortality in adult patients with methicillin-resistant Staphylococcus aureus bloodstream infection: a meta-analysis and systematic review.

BACKGROUND: Cases of methicillin-resistant Staphylococcus aureus (MRSA) bloodstream infection have been increasing. Patients with MRSA bloodstream infection have a poor prognosis and high mortality rate. Identification of potential risk factors associated with MRSA bloodstream infection-related mortality may help improve patient outcomes. METHODS: Embase, PubMed, and the Cochrane Library databases were searched to identify articles describing predictors of mortality in patients with MRSA bloodstream infections. Two investigators independently assessed articles for inclusion and data extraction. RESULTS: Twenty observational studies were included in the analysis. Factors associated with higher mortality were development of severe sepsis or septic shock [odds ratio (OR): 4.56, 95% CI: 3.37-6.18], congestive heart failure (OR: 1.78, 95% CI: 1.27-2.50), liver cirrhosis (OR: 1.90, 95% CI: 1.27-2.65), malignancy (OR: 1.62, 95% CI: 1.33-1.98), infective endocarditis (OR: 2.05, 95% CI: 1.35-3.11), nosocomial infection (OR: 2.80, 95% CI: 1.41-5.55), intensive care unit admission (OR: 3.08, 95% CI: 1.49-6.36) and inappropriate empirical antimicrobial treatment (OR: 2.25, 95% CI: 1.16-4.36); removal of the eradicable foci was a protective factor (OR: 0.51, 95% CI: 0.40-0.63) The average APACHE II score at the time of diagnosis of MRSA bloodstream infection was considerably higher in patients who did not survive than in those who survived [weighted mean difference (WMD): 5.81, 95% CI: 3.03-8.59]. DISCUSSION: Patient condition, appropriate timing of antimicrobial treatment, surgical intervention and disease severity according to the APACHE II score are the most important risk factors for death in patients with MRSA bloodstream infections.

Safety and efficacy of oral nemonoxacin versus levofloxacin in treatment of community-acquired pneumonia: A phase 3, multicenter, randomized, double-blind, double-dummy, active-controlled, non-inferiority trial.

BACKGROUND/PURPOSE: Nemonoxacin is a novel nonfluorinated quinolone with excellent in vitro activity against most pathogens in community-acquired pneumonia (CAP), especially Gram-positive isolates. The purpose of this study was to assess the efficacy and safety of nemonoxacin compared with levofloxacin in patients with CAP. METHODS: A phase 3, multicenter, randomized (2:1) controlled trial was conducted in adult CAP patients receiving nemonoxacin 500 mg or levofloxacin 500 mg orally once daily for 7-10 days. Clinical, microbiological response and adverse events were assessed. Non-inferiority was determined in terms of clinical cure rate of nemonoxacin compared with that of levofloxacin in a modified intention-to-treat (mITT) population. NCT registration number: NCT01529476. RESULTS: A total of 527 patients were randomized and treated with nemonoxacin (n = 356) or levofloxacin (n = 171). The clinical cure rate at test-of-cure visit was 94.3% (300/318) for nemonoxacin and 93.5% (143/153) for levofloxacin in the mITT population [difference (95% CI), 0.9% (-3.8%, 5.5%)]. The microbiological success rate was 92.1% (105/114) for nemonoxacin and 91.7% (55/60) for levofloxacin in the bacteriological mITT population [difference (95% CI), 0.4% (-8.1%, 9.0%)]. The incidence of adverse events (AEs) was comparable between nemonoxacin (33.1%, 118/356) and levofloxacin (33.3%, 57/171) (P > 0.05). CONCLUSION: Nemonoxacin 500 mg once daily for 7-10 days is as effective and safe as levofloxacin for treating adult CAP patients in terms of clinical cure rates, microbiological success rates, and safety profile. ClinicalTrials.gov identifier: NCT01529476.

Clinical and Genomic Analysis of Liver Abscess-Causing Klebsiella pneumoniae Identifies New Liver Abscess-Associated Virulence Genes.

Hypervirulent variants of Klebsiella pneumoniae (hvKp) that cause invasive community-acquired pyogenic liver abscess (PLA) have emerged globally. Little is known about the virulence determinants associated with hvKp, except for the virulence genes rmpA/A2 and siderophores (iroBCD/iucABCD) carried by the pK2044-like large virulence plasmid. Here, we collected most recent clinical isolates of hvKp from PLA samples in China, and performed clinical, molecular, and genomic sequencing analyses. We found that 90.9% (40/44) of the pathogens causing PLA were K. pneumoniae. Among the 40 LA-Kp, K1 (62.5%), and K2 (17.5%) were the dominant serotypes, and ST23 (47.5%) was the major sequence type. S1-PFGE analyses demonstrated that although 77.5% (31/40) of the LA-Kp isolates harbored a single large virulence plasmid varied in size, 5 (12.5%) isolates had no plasmid and 4 (10%) had two or three plasmids. Whole genome sequencing and comparative analysis of 3 LA-Kp and 3 non-LA-Kp identified 133 genes present only in LA-Kp. Further, large scale screening of the 133 genes in 45 LA-Kp and 103 non-LA-Kp genome sequences from public databases identified 30 genes that were highly associated with LA-Kp, including iroBCD, iucABCD and rmpA/A2 and 21 new genes. Then, these 21 new genes were analyzed in 40 LA-Kp and 86 non-LA-Kp clinical isolates collected in this study by PCR, showing that new genes were present 80-100% among LA-Kp isolates while 2-11% in K. pneumoniae isolates from sputum and urine. Several of the 21 genes have been proposed as virulence factors in other bacteria, such as the gene encoding SAM-dependent methyltransferase and pagO which protects bacteria from phagocytosis. Taken together, these genes are likely new virulence factors contributing to the hypervirulence phenotype of hvKp, and may deepen our understanding of virulence mechanism of hvKp.

Prevalence of the oqxAB gene complex in Klebsiella pneumoniae and Escherichia coli clinical isolates.

OBJECTIVES: To investigate the epidemiology and genetic elements of the efflux pump gene, oqxAB, in clinical isolates of Escherichia coli and Klebsiella pneumoniae. METHODS: The prevalence of the oqxAB gene in a total of 308 consecutive clinical isolates of E. coli, K. pneumoniae and other Klebsiella spp. was investigated by PCR amplification. The full-length oqxAB gene was sequenced. Conjugation experiments were carried out in oqxAB-positive E. coli strains. RESULTS: Of 136 E. coli strains, 71.3% and 70.6% were non-susceptible to ciprofloxacin and levofloxacin, respectively, while 66.9% and 50.7% of the 154 K. pneumoniae were non-susceptible to these two quinolones. oqxA and oqxB were present in 6.6% of E. coli and in all K. pneumoniae strains. The oqxA and oqxB sequences of E. coli and randomly selected K. pneumoniae strains showed high similarity to the original oqxAB sequence of pOLA52. One or two amino acid substitutions were detected in the OqxA or OqxB sequences from two E. coli strains and were designated oqxA2, oqxB2 and oqxB3. oqxAB was transferred in seven of nine oqxAB-positive E. coli strains, and transconjugants showed 2- to 256-fold increases in ciprofloxacin and levofloxacin MICs relative to that for the recipient. CONCLUSIONS: Variants of the oqxAB gene, oqxA2, oqxB2 and oqxB3, were identified in two E. coli strains. The oqxAB gene was present in all K. pneumoniae strains studied and is likely located on the chromosome, thus identifying the genome of K. pneumoniae as a possible reservoir of oqxAB.