Cefdinir: a review of its use in the management of mild-to-moderate bacterial infections

Nanomaterial-assisted molecularly imprinted polymer strategies for highly sensitive and selective determination of cefdinir and its validation using computational approach

In this study, the first nanomaterial-supported molecularly imprinted polymer (MIP)-based electrochemical approach was proposed to achieve the successful detection of cefdinir (CFD). Here, p-amino benzoic acid (p-ABA) was used as the monomer and the photopolymerization method was chosen to form MIP on a glassy carbon electrode (GCE). ZnO nanoparticles (ZnO NPs) were added to the MIP sensor to increase sensitivity and create high porosity. Through the use of cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), characterization investigations confirmed the alterations at each stage of the MIP production process. Electrochemical (cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS)) and scanning electron microscopy (SEM) methods were used for study the characterization studies of the MIP-based nanocomposite sensor. The measurement of MIP parameters, such as the addition of nanoparticles, the removal procedure, the rebinding period, the monomer ratio, etc., was done using the differential pulse voltammetry (DPV). The findings showed that when ZnO NPs were added, the signal was three times higher than when MIPs were used alone. Under the optimized conditions, CFD/4-ABA@ZnONPs/MIP/GCE showed a linear response in the concentration range between 7.5 pM and 100 pM with LOD and LOQ values of 2.06 pM and 6.86 pM, respectively. Anions, cations, and substances including uric acid, ascorbic acid, paracetamol, and dopamine were all used in the selectivity test. In addition, the imprinting factor (IF) study was carried out using compounds such as cefuroxime, cefazolin, cefixime, ceftazidime, and ceftriaxone, which have structural similarities with CFD, as well as impurities such as thiazolylacetyl glycine oxime (IMP-A), thiazolylacetyl glycine oxime acetal (IMP-B), and cefdinir lactone (IMP-E). The results showed that the proposed sensor was selective for CFD, as evidenced by the relative IF values of these impurities. The recovery studies of CFD were successfully applied to tablet dosage form samples, and the developed sensor demonstrated significant sensitivity and selectivity for rapid detection of CFD in tablet dosage form.

In vitro effects of the new oral β-lactamase inhibitor xeruborbactam in combination with oral β-lactams against clinical Mycobacterium abscessus isolates

Non-tuberculosis mycobacteria (NTM), particularly Mycobacterium abscessus subsp. abscessus (M. abscessus), are increasingly being recognized as etiological agents of NTM pulmonary disease. However, treatment options for M. abscessus are limited owing to their natural resistance to most antibiotics, including β-lactams. M. abscessus produces a class A β-lactamase, whose activity is inhibited by cyclic boronic acid β-lactamase inhibitors. We aimed to evaluate the in vitro effects of xeruborbactam, a cyclic boronic acid β-lactamase inhibitor, against M. abscessus when combined with five β-lactams (amoxicillin, tebipenem, cefdinir, cefuroxime, and cefoxitin). The drug susceptibilities of 43 M. abscessus clinical isolates obtained from 43 patients between August 2005 and May 2014 were tested. The MIC results for each β-lactam with or without 4 µg/mL xeruborbactam were examined. Xeruborbactam lowered the MIC90 values of tebipenem, amoxicillin, cefuroxime, and cefdinir by 5, ≥4, 3, and 3 dilutions, respectively. The MIC90 values of cefoxitin without xeruborbactam were 32 µg/mL and did not change upon the addition of xeruborbactam. The lowest MIC90 value was obtained for tebipenem with xeruborbactam. Almost all isolates had an MIC of 4 µg/mL; one isolate had an MIC of 2 µg/mL. With respect to the susceptibility to the same family drug, the number of susceptible isolates increased from 1/43 (2%) to 43/43 (100%) for tebipenem with xeruborbactam. Combining tebipenem and xeruborbactam could be considered an effective all-oral regimen that benefits outpatient treatment of M. abscessus pulmonary disease.

IMPORTANCE

Mycobacterium abscessus subsp. abscessus (M. abscessus) disease is treated in two phases; injectable drugs for initial followed by others for continuation. There is a need to develop all-oral treatment methods for M. abscessus infection, especially in the continuation phase. However, treatment options for M. abscessus are limited owing to their natural resistance to most antibiotics. This is the first report to evaluate the in vitro effects of xeruborbactam, a cyclic boronic acid β-lactamase inhibitor capable of inhibiting the class A β-lactamase produced by M. abscessus, against 43 M. abscessus clinical isolates when combined with five β-lactam antibiotics. Xeruborbactam lowered the MIC90 values of tebipenem by five dilutions, and the number of susceptible isolates increased from 1/43 (2%) to 43/43 (100%). We showed that the tebipenem-xeruborbactam combination might be of interest to explore further as a potentially effective oral regimen for outpatient treatment of M. abscessus pulmonary disease.

Synergistic bactericidal activity of a novel dual β-lactam combination against methicillin-resistant Staphylococcus aureus

OBJECTIVES

MRSA is a major cause of hospital-acquired and community-acquired infections. Treatment options for MRSA are limited because of the rapid development of β-lactam resistance. Combining antibiotics offers an affordable, time-saving, viable and efficient approach for developing novel antimicrobial therapies. Both amoxicillin and cefdinir are oral β-lactams with indications for a wide range of bacterial infections and mild side effects. This study aimed to investigate the in vitro and in vivo efficacy of combining these two β-lactams against MRSA strains.

METHODS

Fourteen representative prevalent MRSA strains with diverse sequence types (STs) were tested with a combination of amoxicillin and cefdinir, using chequerboard and time-kill assays. The Galleria mellonella larvae infection model was used to evaluate the in vivo efficacy of this dual combination against the community-acquired MRSA (CA-MRSA) strain USA300 and the hospital-acquired MRSA (HA-MRSA) strain COL.

RESULTS

The chequerboard assay revealed a synergistic activity of the dual amoxicillin/cefdinir combination against all tested MRSA strains, with fractional inhibitory concentration index (FICI) values below 0.5 and at least a 4-fold reduction in the MICs of both antibiotics. Time-kill assays demonstrated synergistic bactericidal activity of this dual combination against the MRSA strain USA300 and strain COL. Moreover, in vivo studies showed that the administration of amoxicillin/cefdinir combination to G. mellonella larvae infected with MRSA strains significantly improved the survival rate up to 82%, which was comparable to the efficacy of vancomycin.

CONCLUSIONS

In vitro and in vivo studies indicate that the dual combination of amoxicillin/cefdinir demonstrates a synergistic bactericidal efficacy against MRSA strains of various STs. Further research is needed to explore its potential as a treatment option for MRSA infections.

Salmonella Grumpensis Causing Diarrhea in Children - Shanghai Municipality, China, 2023

What is already known about this topic?

Foodborne diseases are a growing public health concern with a notable disease burden in China.

What is added by this report?

Two children with diarrhea visited a healthcare facility within 24 hours on August 1 and 2, 2023. Salmonella Grumpensis was detected in their stool samples by the public health laboratory. Whole genome sequencing (WGS) analysis revealed characteristics typical of outbreak strains. Although the origin of the outbreak was unknown, the possibility of a hidden shared infection was deemed feasible.

What are the implications for public health practice?

It underscores the importance of thorough genomic surveillance to promptly detect emerging pathogens. Public health laboratories play a crucial role by utilizing advanced genomic technologies for accurate pathogen identification and timely warning systems.

Pharmacokinetic and Bioequivalence Evaluation of Two Cefprozil Dispersible Tablets in Healthy Chinese Volunteers

This study aimed to assess the bioequivalence of 2 cefprozil dispersible tablet formulations (250 mg) in healthy Chinese volunteers under fasting and fed conditions and to determine the pharmacokinetics of cefprozil. A randomized, single-dose, open-label, 2-formulation, 2-period study was conducted. The elimination period for this study was 7 days. Forty-eight healthy volunteers received 250-mg cefprozil dispersible tablets in each study period under both test and reference conditions. The test and the reference cefprozil were bioequivalent in healthy Chinese volunteers, and there was no significant food effect in individuals receiving either formulation. No serious adverse event was recorded, and no volunteers withdrew from the study.

Are Prophylactic Systemic Antibiotics Required in Patients with Cataract Surgery at Local Anesthesia?

The reduced use of antimicrobial drugs has been recommended worldwide, according to the global action for antimicrobial resistance published in 2015 by the World Health Organization. In this study, we retrospectively reviewed the incidence of surgical site infection in consecutive patients with cataract surgeries at a single hospital in the 6-year process when prophylactic systemic antibiotics were reduced in a step-by-step manner. The entire study period from 2016 to 2022 was divided into five stages, based on the use of systemic antibiotics. In stage 1 with 649 cataract surgeries, an intravenous drip infusion of cefazolin 1 g was given at surgery, followed by oral cefdinir 100 mg in the evening on surgery day and three times for two postoperative days. In stage 2 with 541 cataract surgeries, oral cefdinir 100 mg was given in the late morning before surgery, in the evening, and three times (300 mg in total) for two postoperative days. In stage 3 with 103 cataract surgeries, oral levofloxacin 500 mg was given in the late morning before surgery and once in the morning for two postoperative days. In stage 4 with 545 cataract surgeries, oral levofloxacin 500 mg was given only in the late morning before surgery. In stage 5 with 311 cataract surgeries, no systemic antibiotics were given. As common procedures in all stages, moxifloxacin eye drops were given four times daily as topical antibiotics in the 3 days before surgery and about 2 weeks after surgery. At surgery, the ocular surface was frequently irrigated with saline-diluted povidone iodine at 0.5% working concentration. No postoperative infection was recorded in any stage. This study showed neither harm nor risk in reduced use and, consequently, no use of prophylactic systemic antibiotics in cataract surgery as far as local precautionary measures were secured.

Solid-Phase Extraction (SPE) Technique to Quantify Cefdinir in Human Plasma Using Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)

A biosensitive analysis method development and validation was performed for accurate and rapid quantification of cefdinir (CDR) in human plasma by a liquid chromatography-tandem mass spectrometry technique coupled with electrospray ionization. Analysis was carried out using a C18 column with a flow rate of 1.0 mL/min and operating temperature of 30.0 ± 1°C. The drug was eluted by optimizing the m/z ratios of 396.20 → 227.20 and 428.17 → 241.10, for cefdinir and IS (internal standard), respectively. The intraday precision (%CV) for Cefdinir ranged from 2.8% and 6.7% as lower limit of quantification of quality control (LLOQ QC) and higher level of quantification of quality control (HQC QC), respectively, whereas these value were found to be as 3.0% and 5.6% for LLOQ and HQC, respectively after interday precision. Moreover, accuracy ranged from 107.70% (HQC QC) to 95.5% (LLOQ QC). The extraction mean recovery was found to be 83.91 ± 6.0% for cefdinir and 76.7 ± 6.23% for IS. The drug was stable throughout the analysis period. It was possible to analyze several plasma samples every day since each sample took <2.5 min to run. The method demonstrated successful quantification of CDR in human plasma, followed by pharmacokinetic profiles that were simple, accurate, sensitive and cost-effective.

Predicting Oral Beta-lactam susceptibilities against Streptococcus pneumoniae

BACKGROUND

Oral beta-lactam antimicrobials are not routinely tested against Streptococcus pneumoniae due to presumed susceptibility based upon penicillin minimum inhibitory concentration (MIC) testing. Currently, Clinical and Laboratory Standards Institute provides comments to use penicillin MIC ≤0.06 to predict oral cephalosporin susceptibility. However, no guidance is provided when cefotaxime MIC is known, leading to uncertainty with interpretation. The purpose of this study was to evaluate cefotaxime and penicillin MICs and their respective correlation to oral beta-lactam categorical susceptibility patterns.

METHODS

249 S. pneumoniae isolates were identified by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-ToF) and then tested by broth microdilution method to penicillin, cefotaxime, amoxicillin, cefdinir, cefpodoxime, and cefuroxime.

RESULTS

Using Clinical and Laboratory Standards Institute (CLSI) non-meningitis breakpoints for cefotaxime, 240/249 isolates were classified as susceptible. Of the cefotaxime susceptible isolates, 23% of the isolates are misrepresented as cefdinir susceptible. Amoxicillin correlated well with penicillin MIC breakpoints with only 1 discordant isolate out of 249.

CONCLUSION

The correlation between amoxicillin and penicillin creates a very reliable predictor to determine categorical susceptibility. However oral cephalosporins were not well predicted by either penicillin or cefotaxime leading to the possible risk of treatment failures. Caution should be used when transitioning to oral cephalosporins in cefotaxime susceptible isolates, especially with higher cefotaxime MICs.

Cefdinir and β-Lactamase Inhibitor Independent Efficacy Against Mycobacterium tuberculosis

Background: There is renewed interest in repurposing β-lactam antibiotics for treatment of tuberculosis (TB). We investigated efficacy of cefdinir, that withstand the β-lactamase enzyme present in many bacteria, against drug-susceptible and multi-drug resistant (MDR) Mycobacterium tuberculosis (Mtb).

Methods: Minimum inhibitory concentration (MIC) experiments were performed with Mtb H37Ra, eight drug-susceptible, and 12 MDR-TB clinical isolates with and without the β-lactamase inhibitor, avibactam at 15 mg/L final concentration. Next, we performed dose-response study with Mtb H37Ra in test-tubes followed by a sterilizing activity study in the pre-clinical hollow fiber model of tuberculosis (HFS-TB) study using an MDR-TB clinical strain. Inhibitory sigmoid E_max model was used to describe the relationship between the drug exposure and bacterial burden.

Results: Cefdinir MIC for Mtb H37Ra was 4 and 2 mg/L with or without avibactam, respectively. The MIC of the clinical strains ranged between 0.5 and 16 mg/L. In the test-tube experiments, cefdinir killed 4.93 + 0.07 log₁₀ CFU/ml Mtb H37Ra in 7 days. In the HFS-TB studies, cefdinir showed dose-dependent killing of MDR-TB, without combination of avibactam. The cefdinir PK/PD index linked to the Mtb sterilizing efficacy was identified as the ratio of area under the concentration-time curve to MIC (AUC_0–24/MIC) and optimal exposure was calculated as AUC_0–24/MIC of 578.86. There was no resistance emergence to cefdinir in the HFS-TB.

Conclusion: In the HFS-TB model, cefdinir showed efficacy against both drug susceptible and MDR-TB without combination of β-lactamase inhibitor. However, clinical validation of these findings remains to be determined.

Drug utilization pattern and cost-effectiveness analysis of five most common antibiotics used in Saudi Arabia

Objectives

Inappropriate use of antibiotics is a matter of concern worldwide as that may lead to antimicrobial drug resistance. The objective of current study was to assess drug utilization pattern and cost-effectiveness. Studies are conducted to analyze the pattern of antibiotics prescribing their adherence to standard guidelines and economic impact on the patients in order to promote their rational use.

Methods

The study was designed as a single-centred, cross-sectional retrospective pharmacy database study of prescribing patterns and cost-utility analysis of five most common antibiotics used in Saudi Arabia. Data for the period from 1 January 2019 to 31 December 2019 were used in the study. Demographic characteristics were demonstrated as frequencies and percentages (with Wilson 95% confidence intervals for proportions). The chi-square test (for P-value calculation) was used to compare the adherence of National Antimicrobial Guidelines for prescribing antibiotics in Saudi Arabia.

Key findings

The maximum number of patients was recorded from the age group of 18–35 years (35.97%) and minimum from 72 to 88 years (1.82%). The number of units prescribed was highest for amoxicillin, clavulanic acid (22487) to 42.93% of patients and was lowest for ciprofloxacin (4215) with 8.04%. The longest duration of therapy was for Cefdenir (7.23 days) and lowest for azithromycin (3.58 days). The cost was highest for Cefdenir 38.66SR (10.31USD), and lowest cost was estimated for Cefuroxime 12.43SR (3.31USD).

Conclusions

Our study declared that (amoxicillin with clavulanic acid) was used the most as first-line agents in treating bacterial infections due to their broad coverage against different microbes. Conducting laboratory tests to identify the type of microbe before prescribing could prevent the development of drug resistance and save the antibiotic for future. The cost-to-benefit analysis studies of antibiotics must be conducted for each indication that may promote their rational use.

Pharmacokinetics and Bioequivalence of Cefprozil for Suspension and Granule Formulation in Healthy Chinese Volunteers: Two Single-Dose Crossover Studies

INTRODUCTION

Cefprozil, an oral second-generation semi-synthetic cephalosporin, possesses a broad spectrum of antimicrobial activity. A granule formulation has been developed to improve medication adherence of the patients. This study was conducted to assess the bioequivalence of the granule formulation to a dry suspension in healthy Chinese volunteers and estimate the pharmacokinetic (PK) profiles of cefprozil.

METHODS

An open-label, randomized, single-dose, two-period, two-group, crossover study was conducted in 60 healthy Chinese volunteers under fasted or fed conditions (30 volunteers for each condition) to assess the bioequivalence between two formulations of cefprozil. Blood samples were collected at specified time intervals, and the plasma concentrations of cis- and trans-cefprozil were determined by a validated liquid chromatography-tandem mass spectrometry (LC-MS/MS) method. PK and bioavailability parameters were estimated via non-compartmental methods. Adverse events (AEs) were also recorded.

RESULTS

Under fasted conditions, the mean Cmax was (3534.70 ± 634.67) ng/ml, Tmax was (0.98 ± 0.25) h, t1/2 was (1.37 ± 0.13) h and AUC0-t was (9302.86 ± 1618.39) ng·h/ml, respectively, after a single dose of 125 mg cefprozil for suspension. Under fed conditions, the mean Cmax was (2438.80 ± 493.78) ng/ml, Tmax was (1.66 ± 0.76) h, t1/2 was (1.36 ± 0.24) h and AUC0-t was (9332.36 ± 1373.61) ng·h/ml, respectively. The PK parameters of the granule formulation of cefprozil were similar to those of the suspension. The 90% CI values of the GMRs of Cmax, AUC0-t and AUC0-∞ under both fasted and fed conditions were within the prespecified bioequivalence range (80.00-125.00%).

CONCLUSIONS

According to the criteria for bioequivalence, the test granule formulations of cefprozil and "Cefprozil for Suspension®" were determined to be bioequivalent whether under fasted or fed conditions by measurement of cis-, trans- and total cefprozil.

TRIAL REGISTRATION

ClinicalTrials.gov identifier, NCT04414254.

A network medicine approach to investigation and population-based validation of disease manifestations and drug repurposing for COVID-19

The global coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has led to unprecedented social and economic consequences. The risk of morbidity and mortality due to COVID-19 increases dramatically in the presence of coexisting medical conditions, while the underlying mechanisms remain unclear. Furthermore, there are no approved therapies for COVID-19. This study aims to identify SARS-CoV-2 pathogenesis, disease manifestations, and COVID-19 therapies using network medicine methodologies along with clinical and multi-omics observations. We incorporate SARS-CoV-2 virus-host protein-protein interactions, transcriptomics, and proteomics into the human interactome. Network proximity measurement revealed underlying pathogenesis for broad COVID-19-associated disease manifestations. Analyses of single-cell RNA sequencing data show that co-expression of ACE2 and TMPRSS2 is elevated in absorptive enterocytes from the inflamed ileal tissues of Crohn disease patients compared to uninflamed tissues, revealing shared pathobiology between COVID-19 and inflammatory bowel disease. Integrative analyses of metabolomics and transcriptomics (bulk and single-cell) data from asthma patients indicate that COVID-19 shares an intermediate inflammatory molecular profile with asthma (including IRAK3 and ADRB2). To prioritize potential treatments, we combined network-based prediction and a propensity score (PS) matching observational study of 26,779 individuals from a COVID-19 registry. We identified that melatonin usage (odds ratio [OR] = 0.72, 95% CI 0.56-0.91) is significantly associated with a 28% reduced likelihood of a positive laboratory test result for SARS-CoV-2 confirmed by reverse transcription-polymerase chain reaction assay. Using a PS matching user active comparator design, we determined that melatonin usage was associated with a reduced likelihood of SARS-CoV-2 positive test result compared to use of angiotensin II receptor blockers (OR = 0.70, 95% CI 0.54-0.92) or angiotensin-converting enzyme inhibitors (OR = 0.69, 95% CI 0.52-0.90). Importantly, melatonin usage (OR = 0.48, 95% CI 0.31-0.75) is associated with a 52% reduced likelihood of a positive laboratory test result for SARS-CoV-2 in African Americans after adjusting for age, sex, race, smoking history, and various disease comorbidities using PS matching. In summary, this study presents an integrative network medicine platform for predicting disease manifestations associated with COVID-19 and identifying melatonin for potential prevention and treatment of COVID-19.

Collaboration with an infection control team promoted appropriate antibiotic use for third molar extraction at a Japanese hospital

Oral antibiotic therapy is routinely administered when a third molar (M3) is extracted to prevent infectious complications after surgery. Oral third-generation cephalosporins are frequently used after M3 extraction in Japan but at the expense of an increased risk of antimicrobial resistance. Therefore, the infection control team (ICT) at our institution recommended a reduction in use of these agents after M3 extraction. In this study, we compared the types of antibiotic agents prescribed for patients undergoing M3 extraction before and after this recommendation. We investigated the relationship between type of antibiotic used and the likelihood of infectious complications as well as cost savings in patients who underwent M3 extraction in the 6 months before and after the ICT recommendation in July 2018. There was a marked reduction in use of oral third-generation cephalosporins after M3 extraction (P < 0.0001) and increased use of oral penicillins and first-generation cephalosporins after the ICT recommendation. Moreover, surgical site infection (SSIs) were significantly less common after the ICT recommendation (P = 0.0099); however, the SSI rate was higher in patients who received a third-generation cephalosporin than in those who received penicillin (8.8% vs 0.5%). There was also a significant saving in per-patient antibiotic costs after the ICT recommendation (269.5 ± 282.0 JPY vs 454.7 ± 376.6 JPY; P < 0.0001). These findings suggest that collaboration with an ICT promotes appropriate antibiotic use, decreases the risk of an SSI, and improves the cost-benefit ratio in patients undergoing M3 extraction.

Cefdinir Solid Dispersion Composed of Hydrophilic Polymers with Enhanced Solubility, Dissolution, and Bioavailability in Rats

The aim of this work was to develop cefdinir solid dispersions (CSDs) prepared using hydrophilic polymers with enhanced dissolution/solubility and in vivo oral bioavailability. CSDs were prepared with hydrophilic polymers such as hydroxypropyl-methylcellulose (HPMC; CSD1), carboxymethylcellulose-Na (CMC-Na; CSD2), polyvinyl pyrrolidone K30 (PVP K30; CSD3) at the weight ratio of 1:1 (drug:polymer) using a spray-drying method. The prepared CSDs were characterized by aqueous solubility, differential scanning calorimetry (DSC), powder X-ray diffraction (p-XRD), scanning electron microscopy (SEM), aqueous viscosity, and dissolution test in various media. The oral bioavailability of CSDs was also evaluated in rats and compared with cefdinir powder suspension. The cefdinir in CSDs was amorphous form, as confirmed in the DSC and p-XRD measurements. The developed CSDs commonly resulted in about 9.0-fold higher solubility of cefdinir and a significantly improved dissolution profile in water and at pH 1.2, compared with cefdinir crystalline powder. Importantly, the in vivo oral absorption (represented as AUC_inf) was markedly increased by 4.30-, 6.77- and 3.01-fold for CSD1, CSD2, and CSD3, respectively, compared with cefdinir suspension in rats. The CSD2 prepared with CMC-Na would provide a promising vehicle to enhance dissolution and bioavailability of cefdinir in vivo.

Hypoglycemia after antimicrobial drug prescription for older patients using sulfonylureas

IMPORTANCE

Certain antimicrobial drugs interact with sulfonylureas to increase the risk of hypoglycemia.

OBJECTIVE

To determine the risk of hypoglycemia and associated costs in older patients prescribed glipizide or glyburide who fill a prescription for an antimicrobial drug.

DESIGN, SETTING, AND PARTICIPANTS

This was a retrospective cohort study of Texas Medicare claims from 2006 to 2009 for patients 66 years or older who were prescribed glipizide or glyburide and who also filled a prescription for 1 of the 16 antimicrobials most commonly prescribed for this population.

METHODS

We assessed hypoglycemia events and associated Medicare costs in patients prescribed 1 of 7 antimicrobial agents thought to interact with sulfonylureas, using noninteracting antimicrobials as a comparison. We used a repeated measure logistic regression, controlling for age, sex, ethnicity, Medicaid eligibility, comorbidity, prior emergency department visits for hypoglycemia, prior hospitalizations for any cause, nursing home residence, and indication for the antimicrobial. We estimated odds of hypoglycemia, number needed to harm, deaths during hospitalization for hypoglycemia, and Medicare costs for hypoglycemia treatment.

MAIN OUTCOMES AND MEASURES

Any hospitalization or emergency department visit owing to hypoglycemia within 14 days of antimicrobial exposure.

RESULTS

In multivariable analyses controlling for patient characteristics and indication for antimicrobial drug use, clarithromycin (odds ratio [OR], 3.96 [95% CI, 2.42-6.49]), levofloxacin (OR, 2.60 [95% CI, 2.18-3.10]), sulfamethoxazole-trimethoprim (OR, 2.56 [95% CI, 2.12-3.10]), metronidazole (OR, 2.11 [95% CI, 1.28-3.47]), and ciprofloxacin (OR, 1.62 [95% CI, 1.33-1.97]) were associated with higher rates of hypoglycemia compared with a panel of noninteracting antimicrobials. The number needed to harm ranged from 71 for clarithromycin to 334 for ciprofloxacin. Patient factors associated with hypoglycemia included older age, female sex, black or Hispanic race/ethnicity, higher comorbidity, and prior hypoglycemic episode. In 2009, 28.3% of patients prescribed a sulfonylurea filled a prescription for 1 of these 5 antimicrobials, which were associated with 13.2% of all hypoglycemia events in patients taking sulfonylureas. The treatment of subsequent hypoglycemia adds $30.54 in additional Medicare costs to each prescription of 1 of those 5 antimicrobials given to patients taking sulfonylureas.

CONCLUSIONS AND RELEVANCE

Prescription of interacting antimicrobial drugs to patients on sulfonylureas is very common, and is associated with substantial morbidity and increased costs.

Impact of targeted specific antibiotic delivery for gut microbiota modulation on high-fructose-fed rats

The objective of present investigation was to study the effect of gut microbiota alteration by oral administration of targeted delivery of pH sensitive cefdinir microspheres to high-fructose-fed (HFD) rats. Rats were fed with a high-fructose diet with or without cefdinir microsphere administration for 30 days. The fecal microbiota community, oral glucose tolerance, the markers of liver injury, plasma and hepatic lipids profile, and histological evaluation were investigated. The levels of blood glucose, liver injury markers, lipid profile in plasma and liver, and fat tissue were significantly increased in high-fructose-fed rats. However, after pH-sensitive cefdinir microsphere administration, the elevation of these parameters was significantly suppressed. Cef EL significantly lowered the increased AST (p < 0.05) and ALT (p < 0.001) levels in HFD group. There is a significant lower (p < 0.01) AUCglucose level in Cef EL group than HFD group The histological changes in the liver and the small and large intestines were more profound in HFD group as compared to cefdinir-treated HFD and control groups. Feeding of cefdinir microsphere sustained lactobacilli and bifidobacteria and significantly decreased (p < 0.05) the number of Enterobacteriaceae induced by HFD. Experimental evidences demonstrated that the effectiveness of pH-specific cefdinir microsphere on reducing insulin resistance and development of metabolic changes in high-fructose-fed rats and suggested that it may be a promising therapeutic agent in treating type 2 diabetes. Intestinal-targeted antibiotic delivery needs to be further explored for its therapeutic applications.

Cefdinir: an oral cephalosporin for the treatment of respiratory tract infections and skin and skin structure infections

Cefdinir is an oral third-generation cephalosporin (also known as an advanced-spectrum or generation cephem) with good in vitro activity against the pathogens responsible for community-acquired respiratory tract infections and uncomplicated skin and skin structure infections. The drug distributes very well in respiratory tract tissues and fluids, as well as skin blisters and ear fluids; its pharmacokinetic profile allows once- or twice-daily administration. Oral cefdinir 300 mg twice daily or 600 mg once daily in adults and adolescents, or 14 mg/kg/day in one or two daily doses in pediatric patients, administered for 5 or 10 days, has shown good clinical and bacteriological efficacy, at least equivalent to that of other oral agents in randomized controlled trials conducted in patients with community-acquired pneumonia, acute bacterial exacerbation of chronic bronchitis, sinusitis, acute otitis media, pharyngitis and uncomplicated skin and skin structure infections. Cefdinir is well tolerated and the oral suspension has shown superior taste or palatability over other comparator oral antimicrobial agents. Thus, cefdinir continues to represent an important cephalosporin option for the treatment of adult, adolescent and pediatric patients with mild or moderate respiratory tract or cutaneous infections, especially in areas with elevated rates of beta-lactamase production in Haemophilus influenzae and where resistance to other commonly used agents has emerged (e.g., macrolides, penicillins, tetracyclines, fluoroquinolones and trimethoprim-sulfamethoxazole).

Determination of cefdinir levels in rat plasma and urine by high-performance liquid chromatography-tandem mass spectrometry: application to pharmacokinetics after oral and intravenous administration of cefdinir

A selective and sensitive liquid chromatography tandem mass spectrometry method (LC-MS/MS) was developed and validated for the determination of cefdinir in rat plasma and urine. Following a simple protein precipitation using methanol, chromatographic separation was achieved with a run time of 10 min using a Synergi 4 µ polar-RP 80A column (150 × 2.0 mm, 4 µm) with a mobile phase consisting of 0.1% formic acid in water and methanol (65:35, v/v) at a flow rate of 0.2 mL/min. The protonated precursor and product ion transitions for cefdinir (m/z 396.1 → 227.2) and cefadroxil, an internal standard (m/z 364.2 → 208.0) were monitored in the multiple reaction monitoring in positive ion mode. The calibration curves for plasma and urine were linear over the concentration range 10-10,000 ng/mL. The lower limit of quantification was 10 ng/mL. All accuracy values were between 95.1 and 113.0% and the intra- and inter-day precisions were <13.0% relative standard deviation. The stability under various conditions in rat plasma and urine was also found to be acceptable at three concentrations. The developed method was applied successfully to the pharmacokinetic study of cefdinir after oral and intravenous administration.

Iontophoresis of amoxicillin and cefuroxime: rapid therapeutic concentrations in skin

CONTEXT

Amoxicillin (AMX) and cefuroxime (CFX) are antibiotics used often to treat skin bacterial infections. Typically, high oral doses are required to achieve minimum inhibitory concentration (MIC) at the site of infection that may affect only a very small area of skin.

OBJECTIVES

To lower side effects and increase therapeutic effectiveness, the percutaneous absorption and retention of AMX and CFX administered by iontophoresis was investigated in a rabbit model by measuring dermis concentrations via microdialysis.

METHODS

Iontophoresis was performed using a stainless steel electrode and a non-woven polypropylene pad. The cartridge pad was soaked with a solution of AMX in glycerin or of CFX in glycerin/water (60:40). Constant current density of 0, 100, 200 or 300 µA/cm(2) was applied for 60 min.

RESULTS

For AMX, therapeutically effective skin concentrations were detected immediately after the application of electrical current for any of the current density tested and remained above it for at least 2 h from the end of iontophoresis. For CFX, skin concentrations rose above MIC only at the higher current densities and fell below the MIC by the end of the experiment.

CONCLUSION

Iontophoresis is a promising method to obtain a fast and sustained concentration of AMX and CFX in skin.

Preparation and evaluation of mucoadhesive cefdinir microcapsules

The mucoadhesive microcapsules were prepared by using various concentrations of three different mucoadhesive polymers, namely, chitosan, Carbopol 934P, and methyl cellulose as wall materials and cefdinir as the core material employing orificeionic gelation method. The prepared microcapsules were characterized by scanning electron microscope (SEM) and Fourier transform infrared spectrometry (FT-IR). The prepared microcapsules were found to be spherical with particle size ranging from 765±20 to 985±10 μm and encapsulation efficiencies in the range of 55%-92%. The formulation containing Carbopol 934P as mucoadhesive polymer was found to be best with particle size 946±10 μm. The ex vivo wash-off test showed that the mucoadhesion after 1 h was 80% and the in vitro drug release was extended for more than 12 h. FT-IR spectra indicate that there was no interaction between drug and the polymers used in the formulation. Cefdinir is better absorbed from the upper part of the gastrointestinal tract, it suffers from low oral bioavailability (20-30%), shorter biological half-life (1-2 h), and less transit time. Thus, it can be concluded that microcapsules prepared using Carbopol 934P have promising properties for use as mucoadhesive carrier to increase the residence time of cefdinir.

Cefdinir-induced hepatotoxicity: potential hazards of inappropriate antibiotic use

Drug-induced hepatotoxicity is well recognized but can cause some diagnostic problems, particularly if not previously reported. The present case involves a 22-year-old male who presented with jaundice and elevated liver enzymes after a course of cefdinir (Omnicef) for streptococcal pharyngitis. A diagnosis of drug-induced liver injury was suspected but a liver biopsy was required after his jaundice worsened despite cessation of the presumed offending agent. A short course of steroids was initiated and eventually the jaundice resolved. This case highlights the need to suspect medication-induced liver injury in cases of jaundice, even if not previously reported. In addition, it illustrates the potential for adverse outcomes in situations where antibiotics are used inappropriately or where first line antibiotics are not used for routine infections. We report a case of a young male who developed jaundice associated with cefdinir use with pathological confirmation of moderate cholestasis with portal and lobular mixed inflammation and focal bile duct injury consistent with drug-induced liver injury.

Effect of beta-cyclodextrin and hydroxypropyl beta-cyclodextrin complexation on physicochemical properties and antimicrobial activity of cefdinir

The solid-state properties, dissolution profile and antimicrobial activity of inclusion complexes of cefdinir (CEF) with beta-cyclodextrin (betaCD) and hydroxypropyl beta-cyclodextrin (HPbetaCD) were investigated. The phase solubility profiles of cefdinir with betaCD and HPbetaCD were classified as A(L)-type, which indicates the formation of 1:1 stoichiometry inclusion complexes. Stability constants with 1:1 molar ratio obtained from the phase solubility diagrams were 120.38+/-1.07 and 58.60+/-1.20 M(-1) for betaCD and HPbetaCD, respectively. Binary systems of CEF with betaCD and HPbetaCD prepared by kneading method were characterized by Fourier transformation-infrared spectroscopy (FTIR) and X-ray powder diffractometry (XRD). The aqueous solubility of CEF was enhanced by 101% for betaCD and 23.4% for HPbetaCD, respectively. The dissolution profiles of inclusion complexes were determined and compared with those of CEF alone and their physical mixtures. The dissolution rate of CEF was increased by betaCD and HPbetaCD inclusion complexation moderately. However, the antimicrobial activity of CEF was increased significantly (p<0.001) by betaCD and HPbetaCD inclusion complexation against S. aureus and E. coli. In all these studies, HPbetaCD had superior antimicrobial activity than that of betaCD while betaCD had greater effect on solubility enhancement of CEF.

Guidelines on the treatment of ABRS in adults

Acute bacterial rhinosinusitis (ABRS) is a common reason for healthcare visits, and one of the more common reasons for the use of antibiotics. In an effort to improve the diagnosis and appropriate therapy of ABRS, several guidelines have been developed. Current guidelines recommend extended-spectrum cephalosporins as one of the first-line options for the treatment of this condition. In addition, most cephalosporins recommended by recent guidelines (e.g. cefuroxime axetil, cefpodoxime proxetil and cefdinir) are unlikely to be associated with cross-reactivity with penicillins, and may be considered effective alternatives to amoxicillin in adults who are allergic to penicillin.

Role of oral extended-spectrum cephems in the treatment of acute exacerbation of chronic bronchitis

Risk stratification is the recommended approach for treatment of acute exacerbation of chronic bronchitis (AECB) to optimize the chances of clinical success. The suggested oral therapy for "simple or uncomplicated" AECB, which is predominantly a result of infection due to Haemophilus influenzae, Moraxella catarrhalis, and Streptococcus pneumoniae, includes advanced macrolides and 2nd- or 3rd-generation cephalosporins, in addition to the older 1st-line agents (aminopenicillins, doxycycline, trimethoprim/sulfamethoxazole, and erythromycin). In light of increasing resistance of H. influenzae and S. pneumoniae to the older agents, the specific directed structural modification of the cephalosporin nucleus resulted in the development of extended-spectrum 3rd-generation oral cephems with enhanced beta-lactamase stability and improved activity against Gram-positive pathogens (penicillin-susceptible S. pneumoniae and oxacillin-susceptible Staphylococcus aureus). Analysis of results of double-blind randomized clinical trials assessing efficacy of the extended-spectrum oral cephems published since 2000 demonstrates that both cefdinir and cefditoren have similar point estimates of success in comparison to their comparators (cefuroxime, cefprozil, or Locarbacef), when either the clinical cure or the bacteriologic response was analyzed. Thus, oral extended-spectrum 3rd-generation cephems, which retain antimicrobial efficacy against the traditional respiratory pathogens despite changing resistance patterns, offer excellent coverage against the key pathogens involved in simple or uncomplicated AECB.

Review of the spectrum and potency of orally administered cephalosporins and amoxicillin/clavulanate

The antimicrobial spectrum and in vitro potency of the most frequently prescribed orally administered cephalosporins (cefaclor, cefdinir, cefpodoxime, cefprozil, cefuroxime axetil, cephalexin) and amoxicillin/clavulanate are reviewed. These beta-lactam agents have been widely used in the outpatient arena for the treatment of community-acquired respiratory tract and other mild-to-moderate infections. The data presented here were obtained from critical review articles on each of these compounds. Cephalexin and cefaclor were among the least potent and had the narrowest antimicrobial spectrums against the pathogens evaluated. In contrast, cefdinir, cefpodoxime, cefprozil, and cefuroxime were highly active against penicillin-susceptible Streptococcus pneumoniae and retained some activity against penicillin-intermediate strains, whereas amoxicillin/clavulanate was the most active against S. pneumoniae, including most penicillin nonsusceptible strains. Amoxicillin/clavulanate and cefdinir were the most potent compounds against methicillin (oxacillin)-susceptible Staphylococcus aureus, whereas cefpodoxime was the most potent compound against Haemophilus influenzae. Amoxicillin/clavulanate, cefdinir, and cefpodoxime were also active against Moraxella catarrhalis, including beta-lactamase-producing strains. In summary, orally administered "3rd-generation" or extended spectrum cephalosporins exhibited more balanced spectrums of activity against the principal bacterial pathogens responsible for outpatient respiratory tract and other infections when compared with other widely used oral cephalosporins of earlier generations or amoxicillin alone.

Oral beta-lactams in the treatment of acute bacterial rhinosinusitis

Acute bacterial rhinosinusitis (ABRS) is a well-known complication of viral upper respiratory tract infection and is associated with a significant socioeconomic burden. Difficulties in diagnosis, a substantial spontaneous resolution rate, and growing concerns regarding antimicrobial resistance make the proper management of ABRS quite challenging. Treatment guidelines have been developed, taking into account the major bacterial pathogens, rates of antimicrobial resistance, spontaneous resolution rates, and pharmacokinetic and pharmacodynamic considerations. Optimal choices for initial treatment of ABRS in patients without prior antibacterial exposure include the oral beta-lactam agents amoxicillin/clavulanate, cefdinir, cefpodoxime, and cefuroxime. Clinicians are encouraged to consider the local pathogen distribution and rates of antibacterial resistance in selecting therapy for ABRS.

The efficacy of cefdinir in acute bacterial rhinosinusitis

Acute bacterial rhinosinusitis is a common infection resulting in substantial morbidity. Cefdinir, an oral cephalosporin, has extended-spectrum, bactericidal activity against common acute bacterial rhinosinusitis pathogens, including Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis. Cefdinir shows rapid oral absorption and good respiratory tissue penetration, and may be administered once daily. In randomised clinical trials, cefdinir showed efficacy similar to that of other recommended regimens in the treatment of acute bacterial rhinosinusitis, namely amoxicillin/clavulanate and levofloxacin. Cefdinir is well tolerated and has shown a low propensity to suppress the normal commensal flora. Cefdinir oral suspension is rated highly by children in terms of its taste and smell. As the only once-daily beta-lactam currently recommended by acute bacterial rhinosinusitis guidelines (for first-line use in patients with mild acute bacterial rhinosinusitis and no recent antibacterial use), cefdinir offers a convenient and attractive treatment option.

Mechanisms by which antibiotics promote dissemination of resistant pneumococci in human populations

Mechanisms by which antimicrobials contribute to dissemination of pneumococcal resistance are incompletely characterized. A serial cross-sectional study of nasopharyngeal pneumococcal carriage in healthy, home-living children <or=6 years of age was conducted in four rural communities-two in Utah (1998-2003) and two in Idaho (2002-2003). Prevalence odds ratios for carriage of resistant pneumococci (OR(res)) and of susceptible pneumococci (OR(sus)) were estimated. Dynamic transmission models were developed to facilitate a mechanistic interpretation of OR(res) and OR(sus) and to compare the population impact of distinct antimicrobial classes. A total of 5,667 cultures were obtained; 25% of the cultures were positive, and 29% of isolates exhibited reduced susceptibility to penicillin. The adjusted OR(res) for recent individual and sibling cephalosporin use was 2.2 (95% confidence interval: 1.4, 3.4) and 1.8 (95% confidence interval: 1.0, 3.3), respectively. Neither individual nor sibling penicillin use was associated with increased OR(res). Rather, recent use of penicillins was associated with decreased carriage of susceptible pneumococci (OR(sus) = 0.2, 95% confidence interval: 0.1, 0.3). In simulations, both types of effects promoted dissemination of resistant pneumococci at the population level. Findings show that oral cephalosporins enhance the risk of acquiring resistant pneumococci. Penicillins accelerate clearance of susceptible strains. The effect of penicillins in increasing resistance is shared equally by treated and untreated members of the population.

Cefdinir versus levofloxacin in patients with acute rhinosinusitis of presumed bacterial etiology: a multicenter, randomized, double-blind study

BACKGROUND

Treatment guidelines for acute bacterial rhinosinusitis (ABRS) recommend 10 to 14 days of therapy with high-dose amoxicillin, amoxicillin/clavulanate, cefdinir, cefpodoxime, cefuroxime, a macrolide, or a newer fluoroquinolone, among other agents.

OBJECTIVE

This study compared the clinical efficacy and tolerability of cefdinir and levofloxacin in patients with a diagnosis of acute rhinosinusitis of presumed bacterial origin.

METHODS

In this multicenter, double-blind, noninferiority study, ambulatory adult patients who had signs and symptoms for >7 to 21 days before the screening visit and radiographic findings consistent with acute rhinosinusitis were randomized to receive cefdinir 600 mg or levofloxacin 500 mg, each once daily for 10 days. Clinical and radiologic response rates were determined at the test-of-cure (TOC) visit, which took place 9 to 14 days after the completion of treatment.

RESULTS

Two hundred seventy-one patients (138 cefdinir, 133 levofloxacin) were enrolled and randomized to treatment at 27 study centers in the United States and Poland between November 2003 and March 2004. Of these, 241 (123 cefdinir, 118 levofloxacin) were clinically evaluable. The cefdinir group consisted of 75 women and 48 men, of whom 117 were white and 6 black; their mean (SD) age was 42.5 (14.3) years. The levofloxacin group consisted of 71 women and 47 men, of whom 111 were white and 7 black; their mean age was 40.4 (13.6) years. The 2 groups were similar in terms of presenting signs and symptoms and baseline radiographic findings. The most common presenting symptoms were sinus pain, sinus pressure, and purulent nasal discharge, each of which was reported by > or =89% of patients. Clinical cure rates at the TOC visit in the cefdinir and levofloxacin groups were 83% (102/123) and 86% (101/118), respectively (95% Cl for the difference in cure rates, -12.3 to 7.0). Cefdinir and levofloxacin were comparable in the treatment of infections classified as moderate to severe. The incidence of drug-related adverse events was generally comparable in the 2 treatment groups, although there were significant differences between cefdinir and levofloxacin in the incidence of vaginal moniliasis in women (11% vs 0%, respectively; P = 0.003), drug-related diarrhea (8% vs 1%; P = 0.005), and insomnia (0% vs 4%; P = 0.027). Only 2% of patients discontinued therapy prematurely as a result of a drug-related adverse event.

CONCLUSION

In this population of patients with ABRS, the extended-spectrum cephalosporin cefdinir was as efficacious as the fluoroquinolone levofloxacin, suggesting that cefdinir may be a suitable alternative to the currently recommended fluoroquinolones.

Cefditoren pivoxil: a review of its use in the treatment of bacterial infections

Cefditoren pivoxil (Spectracef, Meiact) is a third-generation oral cephalosporin with a broad spectrum of activity against pathogens, including both Gram-positive and -negative bacteria, and is stable to hydrolysis by many common beta-lactamases. Cefditoren pivoxil is approved for use in the treatment of acute exacerbations of chronic bronchitis (AECB), mild-to-moderate community-acquired pneumonia (CAP), acute maxillary sinusitis, acute pharyngitis/tonsillitis and uncomplicated skin and skin structure infections (indications may differ between countries). In clinical trials in adults and adolescents, cefditoren pivoxil demonstrated good clinical and bacteriological efficacy in AECB, CAP, acute maxillary sinusitis, acute pharyngitis/tonsillitis and uncomplicated skin and skin structure infections and was generally well tolerated. Thus, cefditoren pivoxil is a good option for the treatment of adult and adolescent patients with specific respiratory tract or skin infections, particularly if there is concern about Streptococcus pneumoniae with decreased susceptibility to penicillin, or beta-lactamase-mediated resistance among the common community-acquired pathogens.