Comparative review of imipenem/cilastatin versus meropenem

Drug resistance phenotypes of clinical Klebsiella pneumoniae isolates in the past 20 years in China: a systematic review and meta-analysis

OBJECTIVES

Monitoring the drug resistance phenotypes of Klebsiella pneumoniae is crucial in clinical practice. This study aims to evaluate the prevalence of drug-resistant of clinical K. pneumoniae isolates in China over the past two decades using a systematic review and meta-analysis.

METHODS

We systematically searched five databases for relevant articles published between January 1, 2003 and November 21, 2023. We assessed resistance of clinical K. pneumoniae strains isolated in China over the past 20 years to 15 antibiotics, which were divided into three subgroups.

RESULTS

A total of 177 studies derived from 160 articles were eligible for meta-analysis. The pooled antibiotic resistance rate ranged from 5.01% (for imipenem) to 96.03% (for ampicillin). The pooled rate of resistance to the carbapenem antibiotics imipenem and meropenem was relatively low, and subgroup analyses showed that these rates increased over time. The antibiotic resistance rate showed a geographic trend, being highest in central China and lowest in northwest China. The drug resistance rate was highest in strains isolated in specimens from patients with urinary tract infections.

CONCLUSION

This meta-analysis provides reliable data on the rate of antibiotic resistance of K. pneumoniae grouped according to isolation region, time, and source, which may be helpful for selection of antibiotics for clinical treatment. Areas requiring specific attention include management of the use of carbapenem, improving the prevention and treatment of K. pneumoniae in patients with urinary tract infections, and control of transmission of strains from one region to another.

PBPK modelling for the evaluation of drug-drug interaction between meropenem and valproic acid

AIMS

The present study aimed to quantitatively investigate the potential drug-drug interaction (DDI) mechanism between meropenem (MEPM) and valproic acid (VPA).

METHODS

In the present study, we firstly developed a physiologically based pharmacokinetic (PBPK) model of MEPM and VPA. The verified PBPK model was then used to quantitatively investigate the potential DDI between MEPM and VPA. The effect of genetic polymorphisms of acylpeptide hydrolase (APEH) on DDI was also evaluated.

RESULTS

In our simulation, the plasma concentration of hydrolysate of VPAG decreased to 63% when combined with MEPM. Total plasma concentration of VPA before carbapenem use was 53.61 mg/L, whereas it was 45.42 mg/L during carbapenem use. The inhibition of hydrolysis of VPAG by MEPM alone could not result in a rapid and substantial decrease in the plasma concentration of VPA. Parameter sensitivity analysis showed that the changes of absorption played an important role in the maximum plasma concentration (Cmax) of VPA, whereas area under the plasma concentration-time profile (AUC) was more susceptible to elimination changes. In addition, a decrease in APEH activity had little impact on the plasma pharmacokinetics of VPA.

CONCLUSIONS

The DDI between MEPM and VPA might be a comprehensive result of multiple factors. On the basis of our simulation, interval medication of MEPM injection and VPA immediate release tablet at 4-6 h timed interval was recommended, or intravenous administration of VPA solution was preferred when combination regimen was necessary in a clinical setting.

Carbapenem-Resistant E. coli Adherence to Magnetic Nanoparticles

Carbapenem-resistant Enterobacterales (CRE) is an emerging global concern. Specifically, carbapenemase-producing (CP) E. coli strains in CRE have recently been found in clinical, environmental, and food samples worldwide, causing many hospitalizations and deaths. Their rapid identification and characterization are paramount in control, management options, and treatment choices. Thus, this study aimed to characterize the cell surface properties of carbapenem-resistant (R) E. coli isolates and their interaction with glycan-coated magnetic nanoparticles (gMNPs) compared with carbapenem-susceptible (S) E coli. This study used two groups of bacteria: The first group included E. coli (R) isolates harboring carbapenemases and had no antibiotic exposure. Their initial gMNP-cell binding capacity, with cell surface characteristics, was assessed. In the second group, one of the E. coli (R) isolates and E. coli (S) had long-term serial antibiotic exposure, which we used to observe their cell surface characteristics and gMNP interactions. Initially, cell surface characteristics (cell morphology and cell surface charge) of the E. coli isolates were evaluated using confocal laser scanning microscope (LSCM) and a Zetasizer, respectively. The interaction of gMNPs with the E. coli isolates was assessed through LSCM and transmission electron microscope (TEM). Further, the gMNP-cell attachment was quantified as a concentration factor (CF) through the standard plating method. The results showed that the CF values of all E. coli (R) were significantly different from those of E. coli (S), which could be due to the differences in cell characteristics. The E. coli (R) isolates displayed heterogeneous cell shapes (rod and round cells) and lower negative zeta potential (cell surface charge) values compared to E. coli (S). Further, this research identified the differences in the cell surface characteristics of E. coli (S) under carbapenem exposure, compared to unexposed E. coli (S) that impact their attachment capacity. The gMNPs captured more E. coli (S) cells compared to carbapenem-exposed E. coli (S) and all E. coli (R) isolates. This study clearly found that differences in cell surface characteristics impact their interaction with magnetic nanoparticles. The gained insights aid in further understanding adhesion mechanisms to develop or improve bacterial isolation techniques and diagnostic and treatment methods for CRE.

Mechanism of imipenem-induced mental disorder: A meta-analysis

BACKGROUND

Imipenem is a highly effective carbapenem antibiotic, which is widely used in the treatment of many serious bacterial infections. At the same time, it can also cause some adverse reactions, mental abnormalities are the most concerned central nervous system adverse reactions. Different patients respond differently to imipenem, and the effect of imipenem on psychiatric disorders is unclear. Therefore, meta-analysis summarizing the results of multiple previous studies can provide stronger evidence support for clinical guidelines to guide clinical rational use of imipenem to minimize risks.

AIM

To systematically review the effects of imipenem on mental-health disorders.

METHODS

Method in Cochrane Library, Web of science, PubMed, ProQuest, and China’s biomedical literature databases Wanfang, Weipu and China HowNet, the related literatures about the controlled trials of imipenem-induced mental disorders from the establishment of the database to May 2024 were searched; the included literatures were analyzed using RevMan 5.4 software; and the heterogeneity among the studies was also discussed.

RESULTS

After reviewing the literature published between 2003 and 2017, seven controlled trials with a total of 550 patients were included, with 273 and 277 patients in the control and experimental groups, respectively. The sample size of the study ranged from a minimum of 30 cases to a maximum of 61 cases. Patients in the experimental group were treated with imipenem while the control group was treated with conventional drugs. Meta-analysis showed that the incidence of mental disorders in the experimental group was higher than that in the control group (odds ratio = 3.66, 95% confidence interval: 1.11-12.11, P = 0.030); however, there was no significant difference in the incidence of adverse reactions between the two groups (odds ratio = 0.05, 95% confidence interval: 0.00 to 0.10, P = 0.060). Funnel diagrams showed that the scattered points of each study were symmetrical and distributed in an inverted funnel shape; therefore, there was no publication bias.

CONCLUSION

Imipenem can cause mental disorders in patients. However, the low quality of the included literature may have affected the final results. Therefore, it is necessary to conduct a high-quality randomized controlled study with multiple samples to further confirm the mechanism of imipenem-induced mental disorders and provide effective guidance for clinical treatment.

The clinical significance of pyogenic liver abscess after transarterial chemoembolization or microwave ablation on malignant liver tumors: A retrospective study

Pyogenic liver abscess (PLA) is a rare but severe complication of interventional therapy that has been little studied. We aimed to find the risk factors for PLA after transarterial chemoembolization (TACE) or microwave ablation (MWA), further explore its clinical significance and summarize our experience with its treatment. Twenty-two patients with PLA and 118 randomly selected patients without PLA after TACE/MWA were enrolled. Logistic regression was used to analyze risk factors, a nonparametric test was used to compare recovery duration, the log-rank test was used to compare progression-free survival, and Spearman correlation coefficient was calculated between the time from fever to drainage and the total duration of fever. The disease process and treatment were summarized. Sphincter of Oddi manipulation increased the risk of PLA by 70.781-fold. The PLA group took longer to recover (36.56 ± 16.42 days) than the control group (5.54 ± 4.33 days), and had a shorter progression-free survival. Escherichia coli was the major pathogenic bacterium, and multidrug resistance was found in 8 patients with E coli or Enterococcus faecium. The time from fever to drainage was 15.89 ± 13.78 days, which was positively correlated with the total duration of fever (24.29 ± 18.24 days). Overall, 18 patients recovered, and 4 patients died of PLA, for a mortality rate of 18.18%. The fever of 10 patients (45.45%) was controlled by cefoperazone sodium and sulbactam sodium or piperacillin sodium and tazobactam sodium; the fever of 7 patients (31.81%) was controlled by imipenem and cilastatin sodium; and the fever of 3 patients (13.63%) was controlled by tigecycline. Sphincter of Oddi manipulation is a high-risk factor for PLA after TACE or MWA. PLA can accelerate cancer progression and even lead to death. E coli was the major pathogenic bacterium, and multidrug resistance was most common in E coli and E faecium. Timely drainage and appropriate antibiotics are the key primary measures for treating PLA. Cefoperazone sodium and sulbactam sodium or piperacillin sodium and tazobactam sodium is a good choice for the first treatment of PLA, especially before pathogenic bacteria are identified. With the emergence of drug resistance, imipenem and cilastatin sodium, and tigecycline can be used for posterior treatment.

Pharmacokinetic/pharmacodynamic analysis of vancomycin in patients with Enterococcus faecium bacteraemia: a retrospective cohort study

OBJECTIVES

The trough concentration of vancomycin and the area under the concentration-time curve (AUC)/minimum inhibitory concentration (MIC) ratio are crucial in determining vancomycin efficacy against methicillin-resistant Staphylococcus aureus. However, the use of similar pharmacokinetic principles in determining antibiotic efficacy against other gram-positive cocci is lacking. We performed a pharmacokinetic/pharmacodynamic analysis (association of target trough concentration values and AUC/MIC with therapeutic outcome) of vancomycin in patients with Enterococcus faecium bacteraemia.

METHODS

Between January 2014 and December 2021 we performed a retrospective cohort study of patients with E. faecium bacteraemia treated with vancomycin. Patients who received renal replacement therapy or had chronic kidney disease were excluded. Clinical failure, the primary outcome, was defined as a composite of 30-day all-cause mortality, vancomycin-susceptible infection requiring change of treatment, and/or recurrence. AUC24 was estimated using a Bayesian estimation approach based on an individual vancomycin trough concentration. The MIC for vancomycin was determined using a standardised agar dilution method. Additionally, classification was used to identify the vancomycin AUC24/MIC ratio associated with clinical failure.

RESULTS

Of the 151 patients identified, 69 were enrolled. All MICs of vancomycin for E. faecium were ≤1.0 µg/mL. The AUC24 and AUC24/MIC ratio were not significantly different between the clinical failure group and the clinical success group (432±123 µg/mL/hour vs 488±92 µg/mL/hour; p=0.075). However, 7 of 12 patients (58.3%) in the clinical failure group and 49 of 57 patients (86.0%) in the clinical success group had a vancomycin AUC24/MIC ratio ≥389 (p=0.041). No significant association between trough concentration or AUC24 ≥600 µg/mL×hour and acute kidney injury was observed (p=0.365 and p=0.487, respectively).

CONCLUSION

The AUC24/MIC ratio is associated with the clinical outcome of vancomycin administration in E. faecium bacteraemia. In Japan, where vancomycin-resistant enterococcal infection is rare, empirical therapy with a target AUC24 ≥389 should be recommended.

Population pharmacokinetics of meropenem in critically ill patients

Objective

The pharmacokinetics of meropenem are significantly altered in critically ill patients. A population pharmacokinetic study was designed to estimate typical values of meropenem clearance in critically ill patients and evaluate potential factors of influence.

Methods

After meropenem reached a steady state in each patient, two blood samples were taken within the dose interval. The one-compartment pharmacokinetic model based on the data from 101 intensive care unit patients was built using NONMEM software.

Results

Typical values of meropenem clearance and volume of distribution were 3.80 L/h and 3.52 L, respectively. In the final model, meropenem clearance was influenced by serum concentrations of creatinine (CRE), leukocyte count (WBC), hypertension (HTA), and concomitant use of vancomycin (VAN) or colistimethate (COL): CL (L/h) = 5.29 × CRE ^ 0.000001 × WBCs ^ (-0.165) + 0.000001 × HTA + 0.825 × VAN + 1.28 × COL.

Conclusion

In order to achieve effective plasma concentrations of meropenem in critically ill patients, the meropenem dosing regimen should be adjusted according to individual values of drug clearance.

Virulence determinants and antibiotic resistance in staphylococci isolated from the skin of captive bred reptiles

Knowledge of the composition and properties of skin microbiota in healthy reptiles is essential for preservation strategies and thus the prevention of skin dysbiosis leading to dermatological diseases. Despite the greatly increasing popularity of reptiles as pets, only a few studies have dealt with this topic. Therefore, the aim of this work was to analyse species composition of bacteria isolated from skin swabs of 40 reptiles (17 species) using MALDI-TOF spectrometry and to characterise the virulence properties of identified staphylococci (n = 51). The most common species were Staphylococcus xylosus and S. sciuri. Bacilli, enterococci, Escherichia coli, Salmonella sp. and Acinetobacter sp. were also common. The most frequent antimicrobial resistance in staphylococcal isolates was observed for ampicillin (100.0%) and cefoxitin (98.0%) with the blaZ gene being most prevalent (58.8%). In contrast, all staphylococci were susceptible to gentamicin, kanamycin and imipenem. Slime and biofilm production was observed in 86.3% and 76.5% of isolates, respectively. Gelatinase, DNase, protease and lipase activity was found more rarely (41.2%; 25.5%; 27.5% and 21.6%). Since reptiles are a reservoir of bacteria for their owners, common multi-drug resistance (84.3%, MAR index average 0.29 ± 0.09) and biofilm formation must be kept in mind, especially in the case of injury when handling reptiles.

Ceftazidime-Avibactam resistance in clinical isolates of carbapenem-resistant Klebsiella pneumoniae: A phenotypic and genotypic analysis

OBJECTIVE

To find the prevalence of Ceftazidime-Avibactam (CAZ-AVI) resistant Klebsiella pneumoniae in clinical isolates and to determine the genes responsible for Ceftazidime-Avibactam resistance using PCR.

METHODS

A total of 89 carbapenem resistant Klebsiella pneumoniae from various clinical samples were included in the study. CAZ-AVI resistance was tested using E-test. CAZ-AVI resistant strains were subjected to conventional PCR for detection of carbapenamase genes blaNDM- 1, blaOXA-48, blaVIM, blaIMP, blaKPC.

RESULTS

Of the 89 isolates screened for CAZ-AVI resistance, 45(50.5%) isolates were found to be resistant. 42 isolates were subjected to PCR for detection of β lactamase genes.34 isolates were positive for blaNDM-1 and all 42 isolates were positive for blaOXA-48. Co-expression of NDM-1 and OXA-48 was seen in 34 isolates. Sensitivity of mCIM test to identify a carbapenamse compared to PCR was 61.9%. Sensitivity of eCIM test to identify NDM-1 was 80%.

CONCLUSION

CAZ-AVI was effective in vitro in 49.4% of the isolates. Indicating that CAZ-AVI is a promising addition to antibiotics against CRE as well as a carbapenem sparing drug in ESBL producing organisms. β-Lactamase-related mutations are the main mechanism leading to CAZ-AVI resistance.

Preferential meropenem absorption activated by 1α,25-dihydroxyvitamin D3 and shared with foscarnet, a phosphate transporter substrate, in the rat ileum

Meropenem (MEPM) is used for the treatment of serious infectious diseases solely as. INJECTABLE: Therefore, the development of an oral formulation would expand its clinical utility. To this end, an exact understanding of the absorption characteristics of MEPM is essential. In this study, MEPM absorption in the rat small intestine was investigated using an in situ loop technique and an in vitro diffusion chamber method. The disappearance ratios of MEPM (0.1 mM) were in the order of ileum > duodenum > jejunum. The extensive MEPM disappearance in the ileum was significantly reduced in the presence of foscarnet, a Na+-dependent phosphate transporter (NaPi-T) substrate, whereas glycylsarcosine, thiamine, taurocholic acid, and biapenem had no effects. The mucosal-to-serosal (M-to-S) permeation of MEPM across the rat ileal segments was very small under normal experimental conditions. However, on addition of 1α,25-dihydroxyvitamin D3 (1,25(OH)2D3) to the experimental medium, the M-to-S permeation of MEPM markedly increased, showing a more than 7-fold greater apparent permeation coefficient. The present results suggest that MEPM is preferentially absorbed in the rat ileum, sharing with foscarnet, and that 1,25(OH)2D3 potentially activates the absorption of MEPM there. A likely candidate for involvement in MEPM absorption was NaPi-T or a related transporter.

KPC-2-producing Pseudomonas aeruginosa isolated from wild animals in Brazil

Pseudomonas aeruginosa an opportunistic pathogen that causes infections in hospitals and has high morbidity and mortality rates. In addition, it is a widely distributed environmental bacterium that can colonise a variety of habitats. Although wild animals do not have access to antibiotics, antibacterial resistance in these animals has increasingly been reported worldwide. Although the presence of Klebsiella pneumoniae carbapenemase (KPC) is uncommon in P. aeruginosa, it has been increasingly reported. This study examined KPC-2-producing P. aeruginosa in wild animals. A total of 27 P. aeruginosa isolates were obtained from clinical cases treated at the Microbiology Laboratory of the Veterinary Hospital of UFMT, Brazil. P. aeruginosa and blaKPC-2 carbapenemase resistance genes were identified using PCR. Antimicrobial susceptibility of KPC-producing P. aeruginosa was evaluated using the disk diffusion method. The blaKPC-2 gene was detected in 40.7% of the isolates (11/27). The rates of antimicrobial resistance and intermediate sensitivity were as follows: piperacillin/tazobactam (44.4%), imipenem (29.6%), meropenem (51.8%), amikacin (77.8%), cefepime (85.2%), and ciprofloxacin (70.4%). Twelve isolates were classified as Multidrug-resistant (MDR). This study presents the first report of P. aeruginosa with the blaKPC-2 gene in wild animals in Brazil, highlighting the importance of molecular research on resistance genes in P. aeruginosa from a One-Health perspective.

Ceftazidime/Avibactam and Meropenem/Vaborbactam for the Management of Enterobacterales Infections: A Narrative Review, Clinical Considerations, and Expert Opinion

This comprehensive review examines the unique attributes, distinctions, and clinical implications of ceftazidime-avibactam (CAZ-AVI) and meropenem-vaborbactam (MEM-VAB) against difficult-to-treat Enterobacterales infections. Our manuscript explores these antibiotics' pharmacokinetic and pharmacodynamic properties, antimicrobial activities, in vitro susceptibility testing, and clinical data. Moreover, it includes a meticulous examination of comparative clinical and microbiological studies, assessed and presented to provide clarity in making informed treatment choices for clinicians. Finally, we propose an expert opinion from a microbiological and a clinical point of view about their use in appropriate clinical settings. This is the first review aiming to provide healthcare professionals with valuable insights for making informed treatment decisions when combating carbapenem-resistant pathogens.

Assessment of the impact of intravenous antibiotics treatment on gut microbiota in patients: Clinical data from pre-and post-cardiac surgery

Background and aims

Surgical site infection is a common complication after surgery. Periprocedural antibiotics are necessary to prescribe for preventing or treating infections. The present study aimed to explore the effect of intravenous antibiotics on gut microbiota and menaquinone biosynthesis in patients, especially in elderly patients undergoing cardiac surgery.

Methods

A total of 388 fecal samples were collected from 154 cardiac surgery patients. The V3-V4 hypervariable region of the bacterial 16S rRNA gene was amplified and sequenced on a MiSeq PE300. The gut microbiota diversity of samples was analyzed in terms of α- and β-diversity at the OTU level. The different groups were classified according to antibiotics in combinations and single antibiotics. PICRUSt2 was used for preliminary prediction of the gut microbiota function for menaquinone biosynthesis.

Results

The intravenously administered antibiotics which are excreted via bile represents the main antibiotics that could disturb the gut microbiota's composition in cardiac surgery patients, especially for elderly patients. The effect of antibiotics on gut microbiota is produced after antibiotics treatments over one week. The recovery of gut microbiota to the state of pre-antibiotics may require over two weeks of antibiotics withdrawal. Sex factor doesn't represent as an influencer in gut microbiota composition. Long-term use of cefoperazone-sulbactam may affect coagulation function.

Conclusions

The composition of the gut microbiota had a significant change post-intravenous antibiotics treatment in cardiac surgery patients. The richness and diversity of gut microbiota are increased in elderly patients.

Cerebrospinal fluid concentrations of fluoroquinolones and carbapenems in tuberculosis meningitis

Background: Tuberculosis meningitis (TBM) is the most lethal form of TB. It is difficult to treat in part due to poor or uncertain drug penetration into the central nervous system (CNS). To help fill this knowledge gap, we evaluated the cerebrospinal fluid (CSF) concentrations of fluoroquinolones and carbapenems in patients being treated for TBM. Methods: Serial serum and CSF samples were collected from hospitalized patients being treated for TBM. CSF was collected from routine lumbar punctures between alternating timepoints of 2 and 6 h after drug administration to capture early and late CSF penetration. Rich serum sampling was collected after drug administration on day 28 for non-compartmental analysis. Results: Among 22 patients treated for TBM (8 with confirmed disease), there was high use of fluoroquinolones (levofloxacin, 21; moxifloxacin, 10; ofloxacin, 6) and carbapenems (imipenem, 11; meropenem, 6). Median CSF total concentrations of levofloxacin at 2 and 6 h were 1.34 mg/L and 3.36 mg/L with adjusted CSF/serum ratios of 0.41 and 0.63, respectively. For moxifloxacin, the median CSF total concentrations at 2 and 6 h were 0.78 mg/L and 1.02 mg/L with adjusted CSF/serum ratios of 0.44 and 0.62. Serum and CSF concentrations of moxifloxacin were not affected by rifampin use. Among the 76 CSF samples measured for carbapenem concentrations, 79% were undetectable or below the limit of detection. Conclusion: Fluoroquinolones demonstrated high CSF penetration indicating their potential usefulness for the treatment of TBM. Carbapenems had lower than expected CSF concentrations.

Plethora of Antibiotics Usage and Evaluation of Carbapenem Prescribing Pattern in Intensive Care Units: A Single-Center Experience of Malaysian Academic Hospital

Excessive antibiotic consumption is still common among critically ill patients admitted to intensive care units (ICU), especially during the coronavirus disease 2019 (COVID-19) period. Moreover, information regarding antimicrobial consumption among ICUs in South-East Asia remains scarce and limited. This study aims to determine antibiotics utilization in ICUs by measuring antibiotics consumption over the past six years (2016−2021) and specifically evaluating carbapenems prescribed in a COVID-19 ICU and a general intensive care unit (GICU) during the second year of the COVID-19 pandemic. (2) Methods: This is a retrospective cross-sectional observational analysis of antibiotics consumption and carbapenems prescriptions. Antibiotic utilization data were estimated using the WHO Defined Daily Doses (DDD). Carbapenems prescription information was extracted from the audits conducted by ward pharmacists. Patients who were prescribed carbapenems during their admission to COVID-19 ICU and GICU were included. Patients who passed away before being reviewed by the pharmacists were excluded. (3) Results: In general, antibiotics consumption increased markedly in the year 2021 when compared to previous years. Majority of carbapenems were prescribed empirically (86.8%). Comparing COVID-19 ICU and GICU, the reasons for empirical carbapenems therapy in COVID-19 ICU was predominantly for therapy escalation (64.7% COVID-19 ICU vs. 34% GICU, p < 0.001), whereas empirical prescription in GICU was for coverage of extended-spectrum beta-lactamases (ESBL) gram-negative bacteria (GNB) (45.3% GICU vs. 22.4% COVID-19 ICU, p = 0.005). Despite microbiological evidence, the empirical carbapenems were continued for a median (interquartile range (IQR)) of seven (5−8) days. This implies the need for a rapid diagnostic assay on direct specimens, together with comprehensive antimicrobial stewardship (AMS) discourse with intensivists to address this issue.

Interactions between meropenem and renal drug transporters

BACKGROUND

Meropenem is a carbapenem antibiotic and commonly used with other antibiotics for the treatment of bacterial infections. It is primarily eliminated renally by glomerular filtration and renal tubular secretion.

OBJECTIVE

To evaluate the roles of renal uptake and efflux transporters in the excretion of meropenem and potential drug interactions mediated by renal drug transporters.

METHOD

Uptake and inhibition studies were conducted in human embryonic kidney 293 cells stably transfected with organic anion transporter (OAT) 1, OAT3, multidrug and toxin extrusion protein (MATE) 1 and MATE2K, as well as membrane vesicles containing breast cancer resistance-related protein (BCRP), multidrug resistance protein 1 (MDR1) and multidrug resistance-associated protein 2 (MRP2). Probenecid and piperacillin were used to assess potential drug interactions with meropenem in rats.

RESULTS

We observed that meropenem was a low-affinity substrate of OAT1/3 and had a weak inhibitory effect on OAT1/3 and MATE2K. BCRP, MDR1, MRP2, MATE1 and MATE2K could not mediate renal excretion of meropenem. Moreover, meropenem was not an inhibitor of BCRP, MDR1, MRP2 or MATE1. Among five tested antibiotics, moderate inhibition on OAT3-mediated meropenem uptake was observed for linezolid (IC50 value was 69.2 μM), weak inhibition was observed for piperacillin, benzylpenicillin and tazobactam (IC50 values were 282.2, 308.0 and 668.1 μM, respectively), and no inhibition was observed for sulbactam. Although piperacillin had a relatively high drug-drug interaction index (ratio of maximal unbound plasma concentration to IC50 was 1.42) in vitro, it had no meaningful impact on the pharmacokinetics of meropenem in rats.

CONCLUSION

Our results indicate that clinically significant interactions between meropenem and these five antibiotics are low.

Antimicrobial Susceptibility of Bacterial Isolates from Donkey Uterine Infections, 2018–2021

Background: Endometritis is a common reproductive disease in equine animals. No investigation about the bacterial characteristics and antimicrobial susceptibility pattern of donkeys with endometritis has thus far been reported. Objectives: To determine the common uterine bacterial isolates from donkeys with endometritis and to evaluate their susceptibility to antimicrobials used for the treatment thereof. Study design: Retrospective case-series. Methods: Medical records at an equine clinical diagnostic center were retrospectively reviewed to identify submissions from donkeys with bacterial endometritis between 2018 and 2021. Data were extracted and analyzed descriptively in terms of the frequency of bacterial species, susceptibility to antimicrobials and multidrug resistance. Results: A total of 73 isolates were identified from 30 donkeys, of which 92% of the isolates were Gram-negative bacteria. Mixed cultures were found in 90% of the donkeys. The most common isolates were Escherichiacoli (31.5%) and Acinetobacter spp. (21.9%). Susceptibility testing revealed that amikacin (98%), cefoxitin (95%), trimethoprim-sulfamethoxazole (78%) and gentamicin (74%) were the most efficient agents for donkeys. Multidrug resistance (MDR) was found in 20% of all bacterial isolates, of which all Pseudomonas aeruginosa isolates showed a multidrug resistance profile. Main limitations: The sample size was relatively small, which means a bias of selection may exist. The antimicrobial resistance and MDR of agents without break points were not calculated, which means the relative results may be underestimated in our study. Conclusions: Severe infections were detected in donkeys with endometritis. Antimicrobial resistance and MDR bacteria are not rare in our study. This study demonstrated that bacteria identification and antimicrobial susceptibility testing are highly recommended before the treatment of uterine infections in donkeys. Further studies, including the epidemiological investigation of bacterial endometritis of donkeys, should be conducted to provide a better understanding of this critical problem.

A comparison of the antimicrobial resistance of fecal Bacteroides isolates and assessment of the composition of the intestinal microbiotas of carbapenem-treated and non-treated persons from Belgium and Hungary

The antimicrobial susceptibilities of Bacteroides strains isolated from the feces of imipenem-treated patients from Belgium and Hungary were compared with those isolated from the normal microbiota from these two and five other European countries and assessed. Of the 10 antibiotics tested, highly significant differences were found with cefoxitin (decrease for Belgium and for this two and the five countries from the previous study), clindamycin (decrease for Belgium and for this two and the five countries from the previous study) and moxifloxacin (increase for Belgium and for this two and the five countries from the previous study) relative to normal microbiota strains reported earlier. Imipenem treatment brought about modest, but notable differences in the compositions of the microbiomes where there was less diversity in the treated group relative to the non-treated group.

Role of organic anion transporter 3 in the renal excretion of biapenem and potential drug-drug interactions

Biapenem is a carbapenem antibiotic. It is excreted predominantly through the kidney as unchanged forms. However, the molecular mechanism of renal excretion of biapenem and potential drug-drug interactions (DDIs) were still unknown. In the present study, the role of organic anion transporters (OAT) 1/3 and organic cation transporters (OCT) 2 in the renal excretion of biapenem, and the potential DDIs between biapenem and six clinical commonly prescribed antibiotics and antiviral drugs that acted as substrates or inhibitors of OAT3 were evaluated in vitro. Further, the effect of probenecid on the pharmacokinetics of biapenem was explored in the rats. We observed that biapenem could not inhibit the transport activities of OAT1 or OCT2, while mildly inhibited OAT3 (IC₅₀ >500 μM). Among the tested antibiotics and antiviral drugs, the relatively high DDI index values (maximal unbound plasma concentration over IC₅₀, I_max,u/IC₅₀) were found for piperacillin, linezolid and benzylpenicillin, which were 2.84, 1.7 and 0.62, respectively. Although probenecid had the highest DDI index (27.1) in vitro, no significant impact of it on the pharmacokinetics of biapenem was observed in the rats. Our results indicated that biapenem was primarily eliminated by the glomerular filtration, while OAT3-mediated renal tubular secretion was a minor route. Biapenem is not a clinically relevant substrate or inhibitor because of its low affinity to OAT3. According to current results, it would be safe to use biapenem with other antibiotics and antiviral drugs that acted as substrates or inhibitors of OAT3.