Third-generation cephalosporins

Optimising intracellular delivery of antibiotic loaded PLGA nanoparticles to macrophages

Bacteria can evade antimicrobial therapy by hiding inside host cells such as macrophages. Here we examine the ability of PLGA nanoparticles to deliver antibiotics to intracellular bacteria, specifically focusing upon the impact of nanoparticle size. Different sized Rhodamine-B conjugated PLGA nanoparticles were synthesized and uptake examined in two macrophage cell lines, as well as different epithelial cells, to determine the optimal properties for macrophage uptake. These studies demonstrate macrophages display a consistent increase in uptake with increased PLGA nanoparticle diameter. In a bacteria-macrophage co-culture model, we then examined the efficacy of different sized antibiotic-loaded PLGA nanoparticles against intracellular infections with K. pneumoniae and S. aureus. Increasing the size of antibiotic-loaded PLGA nanoparticles significantly increased their potency against intracellular K. pneumoniae. However, this was not observed for S. aureus, potentially due to the observation these nanoparticles failed to access the compartment in which S. aureus reside. This work demonstrates for the first time that increasing the size of antibiotic-loaded PLGA nanoparticles can significantly enhance antimicrobial efficacy against K. pneumoniae intracellular macrophage infections. However, our S. aureus studies indicate this is not a 'one size fits all' approach for all intracellular infections.

Physical compatibility of ceftriaxone and cefepime in 0.45% sodium chloride, Ringer's lactate solution, and Plasma-Lyte A

OBJECTIVES

The compatibility of intravenous fluids with medications is of paramount concern to pharmacists and is an imperative component of ensuring patient safety. Data regarding the physical compatibility of medications with intravenous fluids has not been examined, or published with conflicting results or the concentrations studied were not consistent with current practice. Our objective was to determine the physical compatibility of ceftriaxone and cefepime in 0.45% sodium chloride, Ringer's lactate solution, and Plasma-Lyte A.

METHODS

An in vitro analysis of the physical compatibility of ceftriaxone and cefepime at 10 mg/mL, 20 mg/mL, and 40 mg/mL concentrations was conducted in 0.45% sodium chloride, Ringer's lactate solution, and Plasma-Lyte A. Admixtures were evaluated in triplicate at hours 0, 1, 5, 8, and 24. Physical compatibility was assessed by visual inspection, spectrophotometry, and pH analysis.

RESULTS

Ceftriaxone 40 mg/mL was found to be physically incompatible in 0.45% sodium chloride and Ringer's lactate solution beyond 5 hours and in Plasma-Lyte A beyond 8 hours. Cefepime was found to be physically incompatible with all fluids and in all concentrations beyond 1 hour.

CONCLUSIONS

This work contributes to the body of literature dedicated to the evaluation of intravenous drug and fluid physical compatibility by identifying demonstrable changes in admixtures containing 0.45% sodium chloride, Plasma-Lyte A, and Ringer's lactate solution. Ceftriaxone should not be administered with 0.45% sodium chloride, Ringer's lactated solution, or Plasma-Lyte A at selected concentrations and time points and cefepime is not considered to be physically compatible at 10 mg/mL, 20 mg/mL, or 40 mg/mL in any of the studied fluids beyond 1 hour.

Redesigning the kinetics of lysozyme amyloid aggregation by cephalosporin molecules

In lysozyme amyloidosis, fibrillar aggregates of lysozyme are associated with severe renal, hepatic, and gastrointestinal manifestations, with no definite therapy. Current drugs are now being tested in amyloidosis clinical trials as aggregation inhibitors to mitigate disease progression. The tetracycline group among antimicrobials in use is in phase II of clinical trials, whereas some macrolides and cephalosporins have shown neuroprotection. In the present study, two cephalosporins, ceftazidime (CZD) and cefotaxime (CXM), and a glycopeptide, vancomycin (VNC), are evaluated for inhibition of amyloid aggregation of hen egg white lysozyme (HEWL) under two conditions (i) 4 M guanidine hydrochloride (GuHCl) at pH 6.5 and 37° C, (ii) At pH 1.5 and 65 °C. Fluorescence quench titration and molecular docking methods report that CZD, CXM, and VNC interact more strongly with the partially folded intermediates (PFI) in comparison to the protein's natural state (N). However, only CZD and CXM proficiently inhibit the aggregation. Transmission electron microscopy, tinctorial assessments, and aggregation kinetics all support oligomer-level inhibition. Transition structures in CZD-HEWL and CXM-HEWL aggregation are shown by circular dichroism (CD). On the other hand, kinetic variables and soluble fraction assays point to a localized association of monomers. Intrinsic fluorescence (IF),1-Anilino 8-naphthalene sulphonic acid, and CD demonstrate structural and conformational modifications redesigning the PFI. GuHCl-induced unfolding and differential scanning fluorimetry suggested that the PFI monomers bound to CZD and CXM exhibited partial stability. Our results present two mechanisms that function in both solution conditions, creating a novel avenue for the screening of putative inhibitors for drug repurposing. We extend our proposed mechanisms in the designing of physical inhibitors of amyloid aggregation considering shorter time frames and foolproof methods.Communicated by Ramaswamy H. Sarma.

A Saudi Woman with Ceftriaxone Induced Fixed Drug Eruption

Background

A fixed drug eruption (FDE) is an immunological cutaneous adverse reaction, classified as a cutaneous adverse drug reaction (CADR) and characterized by well-defined lichenoid lesions that occur at the same site each time. Ceftriaxone is a third-generation antibiotic of cephalosporin antibiotics of the beta-lactam antibiotic family, which has typical in vitro activity against many Gram-negative aerobic bacteria. This is the first clinical case from Saudi Arabia and the fifth in the world to document a woman's experience with recurrent FDE after repeated ceftriaxone use. Case Report. A 25-year-old Saudi woman with a known case of sickle cell anemia (SCA) with a history of avascular necrosis of the right hip after replacement was hospitalized with a pain crisis triggered by an upper respiratory tract infection. The patient denied having a history of allergy previously. Due to fever, leukocytosis, and active follicular tonsillitis, ceftriaxone was started. However, a few hours later she developed lip edema and a fixed drug eruption measuring 7 × 11 cm on the left side of her back. The lesion reformed over a hyperpigmented lesion (4 × 8 cm) that the patient did not report upon initial examination. It turned out that this was due to the intravenous administration of ceftriaxone, a year ago in another hospital. An allergy to ceftriaxone was considered, and steroids and antihistamines were started. The case was labeled as ceftriaxone induced FDE.

Conclusion

Ceftriaxone induced FDE is an uncommon type of allergic reaction that has been reported infrequently. Understanding this condition and the mechanism by which FDE becomes recurrent with the same previous fixed lesion is of great importance for both academic and future research purposes.

Ceftriaxone 1 g versus 2 g per day, for the treatment of community-acquired pneumonia: a retrospective cohort study

Guidelines recommend intravenous (IV) ceftriaxone at a dose of 1-2 g/d as empirical treatment in adults hospitalized with community acquired pneumonia (CAP), with the addition of macrolide. We examined whether 1 g/d of IV ceftriaxone is associated with similar clinical outcomes to those of 2 g/d. This is a single-center, retrospective, cohort study of all adult patients hospitalized at Rabin Medical Center between 2015 and 2018 with CAP. The primary outcome was 30-day all-cause mortality. Risk factors for 30-day all-cause mortality were identified by univariable and multivariable analyses, using logistic regression analysis. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated. A total of 2045 patients were treated with IV ceftriaxone 1 g/d and were and compared to 1944 patients who were treated with 2 g/d. The groups were comparable in their baseline characteristics and their clinical presentation. The 30-day all-cause mortality rate was similar between the groups (301/2045 (14.7%) for 1 g/d vs. 312/1944 (16.0%) for 2 g/d, p = 0.24). The rate of C. difficile infection (CDI) was significantly decreased with 1 g/d compared to 2 g/d (4/2045 (0.2%) vs. 12/1944 (0.6%), p = 0.03) and the length of stay was significantly shorter (median 4 days interquartile range (IQR) 3-7 vs. 5 days IQR 3-8, p = 0.02). None of the blood isolates of Streptococcus pneumoniae were penicillin or ceftriaxone resistant. For hospitalized patients with CAP, IV ceftriaxone 1 g/d was associated with similar mortality rates as IV ceftriaxone 2 g/d, with a decreased rate of CDI and shorter length of stay. Ceftriaxone 1 g/d may be sufficient to treat patients with CAP in countries with low prevalence of drug resistant Streptococcus pneumoniae.

QSAR analysis of five generations of cephalosporins to establish the structural basis of activity against methicillin-resistant and methicillin-sensitive Staphylococcus aureus

Solving the worldwide problem of growing bacterial drug resistance will require a short-run and medium-term strategy. Structure-activity relationship (SAR) and quantitative SAR (QSAR) analyses have recently been utilized to reveal the molecular basis of the antibacterial activity and antibacterial spectrum of penicillins, the use of which is no longer solely empirical. Likewise, a more rational drug design can be achieved with cephalosporins, the largest group of β-lactam antibiotics. The current contribution aimed to establish the molecular and physicochemical basis of the antibacterial activity of five generations of cephalosporins on methicillin-sensitive (MSSA) and methicillin-resistant Staphylococcus aureus (MRSA). With SAR and QSAR analyses, the molecular portions that provide essential and additional antibacterial activity were identified. The substitutions with greater volume and polarity on the R2 side chain of the cephem nucleus increase potency on MSSA. The best effect is produced by substitutions with polar nitrogen atoms at the alpha-carbon (Cα). Substitutions with greater volume and polarity on the R1 side chain further enhance antibacterial activity. In contrast, the effect against MRSA seems to be independent of any substitution on R2 or at the Cα, while depending on the accessory portions with greater volume and polarity on R1.

Extended-spectrum β-lactamase-producing E. coli from retail meat and workers: genetic diversity, virulotyping, pathotyping and the antimicrobial effect of silver nanoparticles

BACKGROUND

The spread of extended-spectrum β-lactamases (ESBL) producing E. coli from food animals and the environment to humans has become a significant public health concern. The objectives of this study were to determine the occurrence, pathotypes, virulotypes, genotypes, and antimicrobial resistance patterns of ESBL-producing E. coli in retail meat samples and workers in retail meat shops in Egypt and to evaluate the bactericidal efficacy of silver nanoparticles (AgNPs-H2O2) against multidrug resistant (MDR) ESBL-producing E. coli.

RESULTS

A total of 250 retail meat samples and 100 human worker samples (hand swabs and stool) were examined for the presence of ESBL- producing E. coli. Duck meat and workers' hand swabs were the highest proportion of ESBL- producing E. coli isolates (81.1%), followed by camel meat (61.5%). Pathotyping revealed that the isolates belonged to groups A and B1. Virulotyping showed that the most prevalent virulence gene was Shiga toxin 2 (stx2) associated gene (36.9%), while none of the isolates harbored stx1 gene. Genotyping of the identified isolates from human and meat sources by REP-PCR showed 100% similarity within the same cluster between human and meat isolates. All isolates were classified as MDR with an average multiple antibiotic resistance (MAR) index of 0.7. AgNPs-H2O2 at concentrations of 0.625, 1.25, 2.5 and 5 μg/mL showed complete bacterial growth inhibition.

CONCLUSIONS

Virulent MDR ESBL-producing E. coli were identified in retail meat products in Egypt, posing significant public health threats. Regular monitoring of ESBL-producing E. coli frequency and antimicrobial resistance profile in retail meat products is crucial to enhance their safety. AgNPs-H2O2 is a promising alternative for treating MDR ESBL-producing E. coli infections and reducing antimicrobial resistance risks.

The CREPE Score: A Predictive Tool for Third-Generation Cephalosporin-Resistant Enterobacterales Pneumonia in Community Settings

Purpose

To evaluate risk factors and develop a prediction score for community-acquired pneumonia caused by third-generation cephalosporin-resistant Enterobacterales (3GCR EB-CAP).

Patients and Methods

A retrospective study was conducted by reviewing the medical records of patients hospitalized with community-acquired pneumonia caused by Enterobacterales (EB-CAP) between January 2015 and August 2021 at Srinagarind Hospital, Khon Kaen University, Thailand. Logistic regression was used to analyze clinical parameters associated with 3GCR EB-CAP. The coefficients of significant parameters were simplified to the nearest whole number for a prediction score, called the CREPE (third-generation Cephalosporin Resistant Enterobacterales community-acquired Pneumonia Evaluation).

Results

A total of 245 patients with microbiologically confirmed EB-CAP (100 in the 3GCR EB group) were analyzed. Independent risk factors for 3GCR EB-CAP included in the CREPE score were (1) recent hospitalization within the past month (1 point), (2) multidrug-resistant EB colonization (1 point), and (3) recent intravenous antibiotic use (2 points for within the past month or 1.5 points for between one and twelve months). The CREPE score had an area under the receiver operating characteristic curve (ROC) of 0.88 (95% CI 0.84-0.93). Using a cut-off point of 1.75, the score had a sensitivity and specificity of 73.5% and 84.6%, respectively.

Conclusion

In areas with high prevalence of EB-CAP, the CREPE score can assist clinicians in selecting appropriate empirical therapy and reducing overuse of broad-spectrum antibiotics.

Attitudes and Practices of the Use of Third-Generation Cephalosporins among Medical Doctors Practicing in Cameroon

BACKGROUND

Third-generation cephalosporins (3GC) are among the most prescribed antibiotics worldwide. Antibiotic resistance, usually due to misuse and overuse, is a feared complication of public health concern. However, there are limited data in Cameroon concerning the knowledge and use of 3GC in our health services. The aim of this study was to assess the knowledge and use of 3GC among medical doctors in Cameroon and to generate baseline information for a wider scale research and policy implementation.

METHODS

This study was a cross-sectional study conducted among medical doctors practicing in Cameroon in general. Convenience sampling was used and the data were collected from both the online questionnaire and the review of files of patients admitted and discharged within the month of April 2021 and analysed with the use of IBM SPSS v25. Results and Discussion. A total of 52 respondents from the online questionnaire and 31 reviewed files were retained. Of the respondents, 27% were female and 73% were male. The mean age and years of experience were 29.6 ± 2.9 and 3.6 ± 2.1 years, respectively. Only 32.7% had correct knowledge of the number of generations of cephalosporins, and 48.1% had knowledge of the antimicrobial target. All medical doctors (MD) identified ceftriaxone as a 3GC, and it was the most commonly prescribed 3GC (71%). Most of the MD considered 3GC to be an efficient antibiotic. Just over half (54.7%) knew the correct posology of ceftriaxone. Only 17% and 9.4% knew the right posology for cefotaxime and ceftazidime, respectively, for the management of early-onset neonatal infection (EONNI). The misuse of 3GC was mostly attributed to nurses, MD, and poor institutional policies.

CONCLUSION

There is average knowledge on 3GC among MD, with ceftriaxone being the most widely known and prescribed. Misuse is common among nurses and doctors. Poor institutional policies and limited laboratory capacities are to be blamed.

Broad vs Narrow Spectrum Antibiotics in Common Bile Duct Stones: A Post Hoc Analysis of an Eastern Association for the Surgery of Trauma Multicenter Study

BACKGROUND

Antimicrobial guidance for common bile duct stones during the perioperative period is limited. We sought to examine the effect of broad-spectrum (BS) vs narrow-spectrum (NS) antibiotics on surgical site infections (SSIs) in patients with common bile duct stones undergoing same-admission cholecystectomy.

STUDY DESIGN

We performed a post hoc analysis of a prospective, observational, multicenter study of patients undergoing same-admission cholecystectomy for choledocholithiasis and/or acute biliary pancreatitis between 2016 and 2019. We excluded patients with cholangitis, perforated cholecystitis, and nonbiliary infections on admission. Patients were divided based on receipt of BS or NS antibiotics. Our primary outcome was the incidence of SSIs, and secondary outcomes included hospital length of stay, acute kidney injury (AKI), and 30-day readmission for SSI.

RESULTS

The cohort had 891 patients: 51.7% (n= 461) received BS antibiotics and 48.3% (n = 430) received NS antibiotics. Overall antibiotic duration was longer in the BS group than in the NS group (6 vs 4 d, p = 0.01); however, there was no difference in rates of SSI (0.9% vs 0.5%, p = 0.7) or 30-day readmission for SSI (1.1% vs 1.2%, p = 1.0). Hospital length of stay was significantly longer in the BS group (p < 0.001) as were rates of AKI (5% vs 1.4%, p = 0.001). On multivariable regression, BS antibiotic use was a risk factor for AKI (adjusted odds ratio 2.8, 95% CI 1.16 to 7.82, p = 0.02).

CONCLUSION

The incidence of SSI and 30-day readmission for SSI was similar between antibiotic groups. However, BS antibiotic use was associated with a longer hospitalization and greater likelihood of AKI.

Mitochondrial Side Effects of Surgical Prophylactic Antibiotics Ceftriaxone and Rifaximin Lead to Bowel Mucosal Damage

Despite their clinical effectiveness, a growing body of evidence has shown that many classes of antibiotics lead to mitochondrial dysfunction. Ceftriaxone and Rifaximin are first choice perioperative antibiotics in gastrointestinal surgery targeting fundamental processes of intestinal bacteria; however, may also have negative consequences for the host cells. In this study, we investigated their direct effect on mitochondrial functions in vitro, together with their impact on ileum, colon and liver tissue. Additionally, their impact on the gastrointestinal microbiome was studied in vivo, in a rat model. Rifaximin significantly impaired the oxidative phosphorylation capacity (OxPhos) and leak respiration in the ileal mucosa, in line with increased oxidative tissue damage and histological changes following treatment. Ceftriaxone prophylaxis led to similar changes in the colon mucosa. The composition and diversity of bacterial communities differed extensively in response to antibiotic pre-treatment. However, the relative abundances of the toxin producing species were not increased. We have confirmed the harmful effects of prophylactic doses of Rifaximin and Ceftriaxone on the intestinal mucosa and that these effects were related to the mitochondrial dysfunction. These experiments raise awareness of mitochondrial side effects of these antibiotics that may be of clinical importance when evaluating their adverse effects on bowel mucosa.

Anti-Salmonella and Antibiofilm Potency of Salvia officinalis L. Essential Oil against Antibiotic-Resistant Salmonella enterica

Raw milk is a significant vehicle for the transmission of different infections. In the present study, we focused on Salmonella enterica from raw milk and its resistance to various antibacterial drugs. Furthermore, we have investigated the antimicrobial and antibiofilm effects of essential oil (EO) obtained from Salvia officinalis L. leaves that were collected from the Aljouf region, Saudi Arabia, against S. enterica. One-dozen strains of S. enterica were found in a batch of a hundred milk samples, and those S. enterica strains were shown to be resistant to several antibiotics, particularly the β-lactam group of antimicrobial drugs. Against multidrug-resistant S. enterica, the inhibitory zones for EO from S. officinalis leaves were found to be 21 mm in diameter. S. officinalis EO at 5% concentration showed a remarkable in vitro inhibitory activity toward the biofilm growth of different S. enterica isolates. Analysis of EO by GC-MS identified 21 distinct components, accounting for 89.94% of the total oil component. The most prominent compounds were 1,8-cineole (39.18%), β-caryophyllene (12.8%), and α--terpineol (10.3%). Taken together, our results unequivocally confirm that the S. officinalis EOs exert numerous bioactivities. Thus, the well-deserved attention on S. officinalis EO usage as a food preservative and adjunctive remedy for bacterial food-borne diseases is justified.

Importance and Reality of TDM for Antibiotics Not Covered by Insurance in Japan

Under the Japanese health insurance system, medicines undergoing therapeutic drug monitoring (TDM) can be billed for medical fees if they meet the specified requirements. In Japan, TDM of vancomycin, teicoplanin, aminoglycosides, and voriconazole, which are used for the treatment of infectious diseases, is common practice. This means the levels of antibiotics are measured in-house using chromatography or other methods. In some facilities, the blood and/or tissue concentrations of other non-TDM drugs are measured by HPLC and are applied to treatment, which is necessary for personalized medicine. This review describes personalized medicine based on the use of chromatography as a result of the current situation in Japan.

Antibiotic-resistance in medically important bacteria isolated from commercial herbal medicines in Africa from 2000 to 2021: a systematic review and meta-analysis

Background

Antimicrobial resistance is swiftly increasing all over the world. In Africa, it manifests more in pathogenic bacteria in form of antibiotic resistance (ABR). On this continent, bacterial contamination of commonly used herbal medicine (HM) is on the increase, but information about antimicrobial resistance in these contaminants is limited due to fragmented studies. Here, we analyzed research that characterized ABR in pathogenic bacteria isolated from HM in Africa since 2000; to generate a comprehensive understanding of the drug-resistant bacterial contamination burden in this region.

Methods

The study was conducted according to standards of the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA). We searched for articles from 12 databases. These were: PubMed, Science Direct, Scifinder scholar, Google scholar, HerbMed, Medline, EMBASE, Cochrane Library, International Pharmaceutical Abstracts, Commonwealth Agricultural Bureau Abstracts, African Journal Online, and Biological Abstracts. Prevalence and ABR traits of bacterial isolates, Cochran’s Q test, and the I² statistic for heterogeneity were evaluated using MedCalcs software. A random-effects model was used to determine the pooled prevalence of ABR traits. The potential sources of heterogeneity were examined through sensitivity analysis, subgroup analysis, and meta-regression at a 95% level of significance.

Findings

Eighteen studies met our inclusion criteria. The pooled prevalence of bacterial resistance to at least one conventional drug was 86.51% (95% CI = 61.247–99.357%). The studies were highly heterogeneous (I² = 99.17%; p < 0.0001), with no evidence of publication bias. The most prevalent multidrug-resistant species was Escherichia coli (24.0%). The most highly resisted drug was Ceftazidime with a pooled prevalence of 95.10% (95% CI = 78.51–99.87%), while the drug-class was 3^rd generation cephalosporins; 91.64% (95% CI = 78.64–96.73%). None of the eligible studies tested isolates for Carbapenem resistance. Extended Spectrum β-lactamase genes were detected in 89 (37.2%) isolates, mostly Salmonella spp., Proteus vulgaris, and K. pneumonia. Resistance plasmids were found in 6 (5.8%) isolates; the heaviest plasmid weighed 23,130 Kilobases, and Proteus vulgaris harbored the majority (n = 5; 83.3%).

Conclusions

Herbal medicines in Africa harbor bacterial contaminants which are highly resistant to conventional medicines. This points to a potential treatment failure when these contaminants are involved in diseases causation. More research on this subject is recommended, to fill the evidence gaps and support the formation of collaborative quality control mechanisms for the herbal medicine industry in Africa.

Cationic Antimicrobial Peptides Are Leading the Way to Combat Oropathogenic Infections

Oral dental infections are one of the most common diseases affecting humans, with caries and periodontal disease having the highest incidence. Caries and periodontal disease arise from infections caused by oral bacterial pathogens. Current misuse and overuse of antibiotic treatments have led to the development of antimicrobial resistance. However, recent studies have shown that cationic antimicrobial peptides are a promising family of antibacterial agents that are active against oral pathogenic bacteria and also possess less propensity for development of antimicrobial resistance. This timely Review has a focus on two primary subjects: (i) the oral bacterial pathogens associated with dental infections and (ii) the current development of antimicrobial peptides targeting oral pathogens.

Antimicrobial-associated anaphylaxis at a tertiary care medical city

BACKGROUND

Antimicrobial-associated anaphylaxis occurs at different rates and can lead to worsening infection-related outcomes, we sought to describe the incidence and complications of such episodes at a tertiary care hospital.

METHOD

A retrospective cohort study was conducted between January 2016 and December 2019. Cases of antimicrobial-associated anaphylaxis were identifiedusing the hospital's electronic healthcare records. Outcomes included: mortality related to anaphylaxis, infection-related mortality, hospitalization and impact on antimicrobial prescribing.

RESULTS

The estimated rate of antimicrobial-associated anaphylaxis was 18.6 (95% CI: 11.8-29.5) cases per 100,000 exposures, which required hospitalization in 23.8% of the cases and ICU admission in 19% of the cases.

CONCLUSION

Implications from antimicrobial-associated anaphylaxis is beyond the episode itself, and can be associated with poor clinical outcomes such as infection-related mortality and hospitalization.

Isolation of third generation cephalosporin resistant Enterobacteriaceae from retail meats and detection of extended spectrum beta-lactamase activity

Various methods have been described to isolate third generation cephalosporin (3GC) resistant Enterobacteriaceae from foods, but it is not known how comparable they are between studies. Here, the performance of five enrichment broths and two selective agars are compared for their ability to isolate 3GC resistant Enterobacteriaceae from retail chicken, beef, pork, and veal samples. The results showed equivalence between Enterobacteriaceae enrichment broth (EE), lauryl sulfate broth (LST), and modified typtone soy broth (mTSB). Lower isolation rates were observed when LST and mTSB were supplemented with the 3GC antibiotic cefotaxime. The overall performance of MacConkey agar supplemented with cefotaxime and a proprietary selective agar (ESBL CHROMagar) was equivalent, although differences linked to the microbiota of specific meat commodities were noted. Regardless of the isolation method, further screening was required to confirm the taxonomy and resistance of the presumptive positive strains. Approximately 40% of confirmed 3GC resistant foodborne Enterobacteriaceae strains tested positive for extended spectrum beta-lactamase (ESBL) activity. Strains that were resistant to ceftriaxone and susceptible to cefoxitin were more likely to test positive for ESBL activity, as were strains that possessed either of two ESBL genes (bla_SHV or bla_TEM). Based on our results, we recommend using an antibiotic-free enrichment broth, two selective agars, and an isolate screening strategy to isolate 3GC resistant Enterobacteriaceae from retail meats. Antibiotic susceptibility testing and/or PCR screening for bla_SHV or bla_TEM can then be used to identify ESBL producing strains among the 3GC resistant meat isolates. The adoption of this approach by the research community will enable more effective monitoring of antibiotic resistance rates and trends among foodborne Enterobacteriaceae over time and across jurisdictions.

Population pharmacokinetics of ceftriaxone administered as continuous or intermittent infusion in critically ill patients

OBJECTIVES

To describe the population pharmacokinetics and protein-binding characteristics of unbound ceftriaxone administered as continuous or intermittent infusion. Additionally, to determine the optimal dosing regimen in critically ill patients.

METHODS

A pharmacokinetic study was performed in the ICU of a tertiary teaching hospital. Patients were treated with ceftriaxone as continuous or intermittent infusion. A population pharmacokinetic model was developed with non-linear mixed-effects analysis. Subsequently, the PTA of a 100% T>MIC was assessed for influential patient characteristics using Monte Carlo simulation.

RESULTS

Fifty-five patients were included. The pharmacokinetics of ceftriaxone was best described by a one-compartment model with non-linear saturable protein binding including the following covariates: body weight, estimated CLCR, serum albumin concentration and mode of administration. For pathogens with an MIC of 1 mg/L, the simulation demonstrated that intermittent infusion of 2 g/24 h only resulted in a ≥90% PTA in patients with a reduced CLCR (0-60 mL/min). Intermittent infusion of 2 g/12 h led to sufficient exposure if CLCR was 0-90 mL/min and continuous infusion of 2 g/24 h led to a ≥90% PTA in all simulations (CLCR 0-180 mL/min).

CONCLUSIONS

In the critically ill, the clearance of unbound ceftriaxone is closely related to CLCR. Furthermore, ceftriaxone protein binding is saturable, variable and dependent on serum albumin concentration. Intermittent dosing of 2 g/24 h ceftriaxone leads to subtherapeutic exposure in patients with a normal or increased CLCR. Treating these patients with continuous infusion of 2 g/24 h is more effective than an intermittent dosing regimen of 2 g/12 h.

Utilization of a complex arrangement approach for spectroscopic examination with Eosin Y of various cephalosporins in their pure or pharmaceutical dosage forms, and in human plasma

Approved, basic, effective and successful spectroscopic strategies (spectrophotometric and spectrofluorimetric) were created to measure seven cephalosporins: cefpiramide (I), cefuroxime (II), cefoxitin (III), ceftazidime (IV), cefpirome (V), ceftobiprole (VI), and ceftriaxone (VII). These strategies used a two-fold complex arrangement response for the drug amino groups with Eosin Y (EY). The examined drugs were determined spectrophotometrically at 542-550 nm in acetic acid derivative buffer. The examined drugs were determined spectrofluorimetrically by measuring their quenching effect on EY local fluorescence at 545 nm after excitation at 305 nm. The absorbance-intensity plots were rectilinear over the ranges 20-100, 10-130, 20-220, 30-230, 10-210, 20-180 and 10-130 μg ml^-1 for I, II, III, IV, V, VI, and VII samples, respectively. The fluorescence-intensity plots were rectilinear over the ranges 0.5-1.5, 0.1-0.9, 0.3-1.5, 0.5-2.5, 0.1-0.9, 0.5-2.5 and 0.1-1.0 μg ml^-1 for I, II, III, IV, V, VI, and VII samples, respectively. The recommended materials were certified as adhering to International Council for Harmonisation (ICH) guidelines and were used to examine the tested drugs in different dosage forms and in human plasma tests. The approved materials matched the reference materials.

Risk comparison of beta-lactam-induced anaphylaxis: Therapeutic stratification analysis in a Vietnamese pharmacovigilance database

WHAT IS KNOWN AND OBJECTIVE

There is limited data on the specific risks of anaphylaxis induced by beta-lactam drugs. The aim of this study was to compare the risks of reporting beta-lactam-induced anaphylaxis using the national pharmacovigilance database of Vietnam (NPDV).

METHODS

The multivariate generalised linear regression model was applied for signal generation and comparison of beta-lactams.

RESULTS

Between 2010 and 2016, there were 2,921 reports of anaphylaxis (19.93%) from 14,655 spontaneous reports of beta-lactam use in the NDPV. Anaphylaxis signal generation was also found for the subgroup J01D (cephalosporins and carbapenems) (ROR = 1.27 [1.16-1.39]) and beta-lactamase-sensitive penicillins (ROR = 1.74 [1.27-2.35]). In the third generation cephalosporin subgroup, different risks were identified for the following combinations of beta-lactams: 1) cefotaxime with cefoperazone+sulbactam; 2) cefixime/cefpodoxime/cefdinir with cefoperazone+sulbactam or ceftizoxime/cefoperazone/ceftazidime/ceftriaxone/cefotaxime. For the second generation cephalosporin subgroup, different risks were found for cefotiam compared to cefmetazole, cefaclor, cefamandole and cefuroxime.

WHAT IS NEW AND CONCLUSION

These findings identified and highlighted the different anaphylactic risks caused by various beta-lactams in the main subgroups.

Antimicrobial susceptibility patterns for aerobic bacteria isolated from reptilian samples submitted to a veterinary diagnostic laboratory: 129 cases (2005-2016)

OBJECTIVE

To identify antimicrobial susceptibility patterns for aerobic bacteria isolated from reptilian samples and, from those patterns, identify antimicrobials that could be considered for empirical treatment of reptiles with suspected bacterial infections.

SAMPLES

129 bacterial isolates from 61 of 127 samples from 96 reptiles.

PROCEDURES

Medical records of reptiles (chelonian, crocodilian, lizard, and snake) presented to the zoological medical service of a veterinary teaching hospital between January 2005 and December 2016 were reviewed for submissions of patient samples for aerobic bacterial culture and susceptibility testing. Sample type, presence or absence of bacterial growth, and antimicrobial susceptibilities of isolated bacteria were recorded. The isolation frequency and the antimicrobial susceptibilities of bacterial genera and species were tabulated.

RESULTS

Pseudomonas spp and Enterococcus spp were the most frequently isolated gram-negative and gram-positive bacteria, respectively. Isolates of gram-negative bacteria frequently had susceptibility to amikacin (86%), gentamicin (95%), tobramycin (92%), and trimethoprim-sulfamethoxazole (83%), and gram-positive bacteria frequently had susceptibility to ampicillin (83%), chloramphenicol (92%), doxycycline (100%), and gentamicin (100%). Isolates of gram-positive bacteria were consistently resistant to ceftazidime.

CONCLUSIONS AND CLINICAL RELEVANCE

Aerobic bacterial culture and antimicrobial susceptibility results for reptilian samples in this population indicated that aminoglycosides and trimethoprim-sulfamethoxazole or ampicillin and doxycycline could be considered as options for the empirical treatment of reptiles with infections caused by gram-negative or gram-positive bacteria, respectively.

Computational design of new enzymes for hydrolysis and synthesis of third-generation cephalosporin antibiotics

Engineering active sites in inert scaffolds to catalyze chemical transformations with unnatural substrates is still a great challenge for enzyme catalysis. In this research, a p-nitrobenzyl esterase from Bacillus subtilis was identified from the structural database, and a double mutant E115A/E188A was designed to afford catalytic activities toward the hydrolysis of ceftizoxime. A quadruple mutant E115A/E188A/L362S/I270A with enhanced catalytic efficiency was created to catalyze the condensation reaction of ethyl-2-methoxy-amino-2-(2-aminothiazole-4-yl) acetate with 7-amino-3-nor-cephalosporanic acid to produce ceftizoxime in a fully aqueous medium. The catalytic efficiencies of the computationally designed mutants E115A/E188A/L362S/I270A and E115A/Y118 K/E188 V/I270A/L362S can be taken as starting points to further improve their properties towards the practical application in designing more ecology-friendly production of third-generation cephalosporins.

The fabrication of an MoS2 QD-AuNP modified screen-printed electrode for the improved electrochemical detection of cefixime

Herein, we report a voltammetric method for the nanomolar detection of cefixime, a third-generation antibiotic. The determination of cefixime is validated on a glassy carbon electrode (GCE) as well as on a screen-printed carbon electrode (SPCE). In the present study, we have reported a facile "one step simple hydrothermal synthesis" of MoS2 quantum dots and with the oxidation of aurochloric acid for the further formation of an MoS2 QD-AuNP composite. The as-synthesized nanocomposite was characterized via UV-Vis spectroscopy, FTIR spectroscopy, XRD, TEM and EDX techniques, and further applied in the modification of working electrodes, showing excellent electroactivity. The sensing of cefixime was done via cyclic and differential pulse voltammetry techniques. The presence of the only anodic peak in the voltammogram reveals the irreversible oxidation of cefixime in the potential range of about 1.3 ± 0.1 V vs. Ag/AgCl. The study was also performed at different scan rates, which indicate a diffusion-controlled mechanism. The proposed cefixime sensor showed a linear response in the concentration range of 0.33-90.82 μM (at S/N = 3) with a limit of detection (LOD) of 3.9-4.5 nm. The electrochemical sensitivity is calculated as 8.63 μA μM-1 cm-2 and 7.07 μA μM-1 cm-2 in buffer and pharmaceutical formulation (commercially available cefixime tablet), respectively. The effects of several interferents were also investigated. The proposed sensor is effectively used for estimating cefixime in phosphate buffer and the commercially available cefixime tablets with no cross-reactivity or matrix effects and shows a promising prospect for real applications.

Association between treatment with oral third-generation cephalosporin antibiotics and mortality outcomes in Ebola virus disease: a multinational retrospective cohort study

OBJECTIVE

To evaluate the association between oral third-generation cephalosporin antibiotic treatment and mortality in Ebola virus disease (EVD).

METHODS

This retrospective cohort studied EVD-infected patients admitted to five Ebola Treatment Units in Sierra Leone and Liberia during 2014-15. Empiric treatment with cefixime 400 mg once daily for five days was the clinical protocol; however, due to resource variability, only a subset of patients received treatment. Data on sociodemographics, clinical characteristics, malaria status and Ebola viral loads were collected. The primary outcome was mortality compared between cases treated with cefixime within 48 h of admission to those not treated within 48 h. Propensity scores were derived using clinical covariates. Mortality between treated and untreated cases was compared using propensity-matched conditional logistic regression and bootstrapped log-linear regression analyses to calculate an odds ratio (OR) and relative risk (RR), respectively, with associated 95% confidence intervals (CI).

RESULTS

Of 424 cases analysed, 360 (84.9%) met the cefixime treatment definition. The mean age was 30.5 years and 40.3% were male. Median cefixime treatment duration was 4 days (IQR: 3, 5). Among cefixime-treated patients, mortality was 54.7% (95% CI: 49.6-59.8%) vs. 73.4% (95% CI: 61.5-82.7%) in untreated patients. In conditional logistic regression, mortality likelihood was significantly lower among cases receiving cefixime (OR = 0.48, 95% CI: 0.32-0.71; P = 0.01). In the bootstrap analysis, a non-significant risk reduction was found with cefixime treatment (RR = 0.82, 95% CI: 0.64-1.16, P = 0.11).

CONCLUSION

Early oral cefixime may be associated with reduced mortality in EVD and warrants further investigation.

Synergy Pattern of Short Cationic Antimicrobial Peptides Against Multidrug-Resistant Pseudomonas aeruginosa

With the rise of various multidrug-resistant (MDR) pathogenic bacteria, worldwide health care is under pressure to respond. Conventional antibiotics are failing and the development of novel classes and alternative strategies is a major priority. Antimicrobial peptides (AMPs) cannot only kill MDR bacteria, but also can be used synergistically with conventional antibiotics. We selected 30 short AMPs from different origins and measured their synergy in combination with polymyxin B, piperacillin, ceftazidime, cefepime, meropenem, imipenem, tetracycline, erythromycin, kanamycin, tobramycin, amikacin, gentamycin, and ciprofloxacin. In total, 403 unique combinations were tested against an MDR Pseudomonas aeruginosa isolate (PA910). As a measure of the synergistic effects, fractional inhibitory concentrations (FICs) were determined using microdilution assays with FICs ranges between 0.25 and 2. A high number of combinations between peptides and polymyxin B, erythromycin, and tetracycline were found to be synergistic. Novel variants of indolicidin also showed a high frequency in synergist interaction. Single amino acid substitutions within the peptides can have a very strong effect on the ability to synergize, making it possible to optimize future drugs toward synergistic interaction.

Ceftiofur-resistant Salmonella enterica serovar Heidelberg of poultry origin - a risk profile using the Codex framework

Codex published the 'Guidelines for Risk Analysis of Foodborne Antimicrobial Resistance' to standardise the approach for evaluating risk posed by foodborne antimicrobial-resistant bacteria. One of the first steps in the guidelines is to compile a risk profile, which provides the current state of knowledge regarding a food safety issue, describes risk management options and recommends next steps. In Canada, ceftiofur/ceftriaxone-resistant Salmonella enterica subsp. enterica serovar Heidelberg from poultry was identified as an antimicrobial resistance (AMR) food safety issue. The first objective of this article was to contextualise this food safety issue, using the risk profile format of the Codex Guidelines. A second objective was to evaluate the applicability of the Codex Guidelines. This risk profile indicated that ceftiofur/ceftriaxone-resistant S. Heidelberg (CSH) was commonly isolated from poultry and was associated with severe disease in humans. Ceftiofur use in poultry hatcheries temporally mirrored the prevalence of CSH from poultry meat at retail and from people with salmonellosis. The evidence was sufficient to indicate the need for risk management options, such as restricting the use of ceftiofur in poultry. The Codex Guidelines provided a useful approach to summarise data for decision-makers to evaluate an AMR food safety issue.

Antibiotic Resistance in Community-Acquired Intra-Abdominal Infections: Diabetes Mellitus as a Risk Factor

Background: Antimicrobial drug resistance in community-acquired (CA) infections is a growing problem. Knowing the local epidemiology is essential to design empirical antibiotic therapy. Therefore, we conducted this study to evaluate the resistance patterns of microorganisms isolated from surgical samples of community-acquired intra-abdominal infections (IAIs) and to determine the factors associated with resistance. Methods: We analyzed retrospectively the records of patients treated from January 2015 to June 2017 who had IAIs with positives aerobic cultures performed in the first 72 hours after admission. Surgical site infections, abdominal wall procedures, peritoneal dialysis catheters, and patients with admissions in the prior month were excluded. To identify the factors associated with resistance, we considered the resistance to the regimen recommended at our institution, ampicillin/sulbactam (AMS) plus ciprofloxacin (CIP). Results: There were 119 patients with 133 isolates, 59% women, and mean age 54 years. The main sources of infection were appendicitis (38%) and cholecystitis (20%), with 64 patients presenting a complicated IAI (cIAI), defined by the presence of peritonitis (55%). Resistance in Enterobacteriaceae was AMS 32% (6.4% intermediate resistance), CIP 31%, cefotaxime 9%, piperacillin/tazobactam (PTZ) 3%, trimethoprim/sulfamethoxazole 32%, gentamicin 9.5%, and amikacin 2%. Considering all patients, resistance to AMS + CIP was 16.8%. Factors associated with resistant to this regimen was, by univariable and multivariable analysis, the presence of diabetes mellitus (odds ratio [OR] 3.6; 95% confidence interval [CI] 1.1-11.6; p = 0.03). Female gender (OR 2.7; CI 0.9-8.4; p = 0.08) and complicated IAI (OR 2.0; CI 0.7-5.4; p = 0.17) were associated with resistance but did not reach statistical significance. Conclusion: High resistance to CIP and AMS was observed. Although the combination of AMS + CIP offers coverage for 84% of patients, PTZ should be considered as an option for patients with severe infections or diabetes mellitus. Finding factors associated with antibiotic resistance could help to select empirical therapy for CA IAIs better.

Determination of ceftriaxone concentration in human cerebrospinal fluid by high-performance liquid chromatography with UV detection

Determination of ceftriaxone (CTRX) concentration in human cerebrospinal fluid (CSF) is required to clarify whether a high concentration of CTRX in CSF is associated with CTRX-induced encephalopathy (CIE). In our study, in order to perform an accurate analysis of CSF sample from CIE patient, we proposed HPLC with UV detection (HPLC-UV) using an octadecylsilica (ODS) column, a methanol and 10 mM phosphoric acid (25:75, v/v) mixture solution as a mobile phase, and a detection wavelength at 280 nm. The linear range was from 0.1 to 100 μg/mL (r = 0.999) in the present HPLC-UV. In the recovery tests using blank samples of human CSF and control serum spiked with CTRX, the recoveries of CTRX were >95.3%, and the RSD (n = 3) was <5.8%. We applied the proposed HPLC-UV system to determine CTRX in the CSF and serum samples obtained from a patient diagnosed as having CIE, and it was revealed that the CTRX concentrations in the CSF sample and the serum were 2.61 and 37.35 μg/mL, respectively. To the best of our knowledge, this is the first report describing the determination of CTRX concentration in a CSF sample obtained from a peritoneal dialysis patient diagnosed as having CIE.

Current and emerging pharmacotherapy for the treatment of bacterial peritonitis

INTRODUCTION

Spontaneous bacterial peritonitis (SBP) is the quintessential model of bacterial infection in cirrhotic patients. In these particularly frail subjects, infections clearly worsen prognosis increasing substantially mortality. Furthermore, treatment of SBP has become more challenging because of the growing impact of multidrug-resistant (MDR) bacteria.

AREAS COVERED

This review addresses the reasons behind the change in therapeutic recommendations for SBP that have occurred in the past few years, by focusing on the following aspects: the importance of an early appropriate empirical treatment, the difference between nosocomial and non-nosocomial forms and the overall microbiological shift (rise of Gram-positive bacteria and MDR strains) that have affected SBP.

EXPERT OPINION

Until recently, third-generation cephalosporins have represented the cornerstone of SBP treatment, a safe choice covering the most important causative agents, namely Enterobacteriaceae. Unfortunately, massive exposure to health systems makes cirrhotic patients prone to MDR infections, which poses significant challenges, all the while not forgetting to strike a balance between effective antimicrobial activity and the risk of toxicity in these fragile subjects. Moreover, there is sparse information about new antibiotics in cirrhotic patients and about drugs levels in ascitic fluid. Therefore, further research is needed to optimize the treatment of SBP.

Role of oral antibiotics for prophylaxis against surgical site infections after elective colorectal surgery

Over the past few decades, surgeons have made many attempts to reduce the incidence of surgical site infections (SSI) after elective colorectal surgery. Routine faecal diversion is no longer practiced in elective colonic surgery and mechanical bowel preparation is on the verge of being eliminated altogether. Intravenous antibiotics have become the standard of care as prophylaxis against SSI for elective colorectal operations. However, the role of oral antibiotics is still being debated. We review the available data evaluating the role of oral antibiotics as prophylaxis for SSI in colorectal surgery.

Antimicrobial resistance and genetic diversity in ceftazidime non-susceptible bacterial pathogens from ready-to-eat street foods in three Taiwanese cities

Bacterial contamination of ready-to-eat (RTE) street foods is a major concern worldwide. Dissemination of antibiotic resistant pathogens from food is an emerging public-health threat. To investigate the prevalence of antibiotic resistance genes and ceftazidime resistance-associated efflux pumps in foodborne pathogens, 270 RTE street foods samples were collected in three densely populated Taiwanese cities. Among 70 ceftazidime non-susceptible isolates, 21 Stenotrophomonas maltophilia, 12 Pseudomonas spp., 22 Acinetobacter spp., and 15 Enterobacteriaceae isolates were identified. Phylogenetic analyses revealed high levels of genetic diversity between all of the different strains. Multi-drug resistance was observed in 86.4% (19/22) of Acinetobacter spp., 100% (12/12) of Pseudomonas spp., 71.4% (15/21) of S. maltophilia, and 93.3% (14/15) of Enterobacteriaceae. Of 70 ceftazidime non-susceptible isolates, 13 contained ESBLs or plasmid-mediated ampC genes and 23 contained ceftazidime resistance-associated efflux pumps, with Acinetobacter spp. identified as predominant isolate (69.6%; 16/23). AdeIJK pump RNA expression in Acinetobacter isolates was 1.9- to 2-fold higher in active efflux strains. Nine clinically resistant genes were detected: catIII and cmlA (chloramphenicol); aacC1, aacC2, aacC3, and aacC4 (gentamicin); tet(A), tet(C), and tet(D) (tetracycline). The scope and abundance of multidrug-resistant bacteria described in this report underscores the need for ongoing and/or expanded RTE monitoring and control measures.

Cefoperazone Induced Gastrointestinal Bleeding

Cefoperazone is a beta-lactam antibiotic which is frequently used in treating a variety of gram positive and gram negative infections. The chemical structure of cefoperazone contains a side chain of N-methylthiotetrazole which can inhibit vitamin K metabolism resulting in hypoprothombinemia. We report a case of cefoperazone induced coagulopathy manifesting as gastrointestinal bleeding. A Naranjo assessment score of 5 was obtained, indicating a probable relationship between the patient's coagulation function disorder and her use of the suspect drug.

In Vitro Susceptibility of Global Surveillance Isolates of Pseudomonas aeruginosa to Ceftazidime-Avibactam (INFORM 2012 to 2014)

Broth microdilution antimicrobial susceptibility testing was performed for ceftazidime-avibactam and comparator agents against 7,062 clinical isolates of Pseudomonas aeruginosa collected from 2012 to 2014 in four geographic regions (Europe, Asia/South Pacific, Latin America, Middle East/Africa) as part of the International Network for Optimal Resistance Monitoring (INFORM) global surveillance program. The majority of isolates were susceptible to ceftazidime-avibactam, with the proportions susceptible differing marginally across the four regions (MIC90, 8 to 16 μg/ml; 88.7 to 93.2% susceptible), in contrast to lower susceptibilities to the following comparator β-lactam agents: ceftazidime (MIC90, 32 to 64 μg/ml; 71.5 to 80.8% susceptible), meropenem (MIC90, >8 μg/ml; 64.9 to 77.4% susceptible), and piperacillin-tazobactam (MIC90, >128 μg/ml; 62.3 to 71.3% susceptible). Compared to the overall population, susceptibility to ceftazidime-avibactam of isolates that were nonsusceptible to ceftazidime (n = 1,627) was reduced to between 56.8% (Middle East/Africa; MIC90, 64 μg/ml) and 68.9% (Asia/South Pacific; MIC90, 128 μg/ml), but these percentages were higher than susceptibilities to other β-lactam agents (0 to 44% susceptible, depending on region and agent; meropenem MIC90, >8 μg/ml; 26.5 to 43.9% susceptible). For this subset of isolates, susceptibilities to amikacin (MIC90, >32 μg/ml; 53.2 to 80.0% susceptible) and colistin (MIC90, 1 μg/ml; 98.5 to 99.5% susceptible) were comparable to or higher than that of ceftazidime-avibactam. A similar observation was made with isolates that were nonsusceptible to meropenem (n = 1,926), with susceptibility to ceftazidime-avibactam between 67.8% (Middle East/Africa; MIC90, 64 μg/ml) and 74.2% (Europe; MIC90, 32 μg/ml) but again with reduced susceptibility to comparators except for amikacin (MIC90, >32 μg/ml; 56.8 to 78.7% susceptible) and colistin (MIC90, 1 μg/ml; 98.9 to 99.3% susceptible). Of the 8% of isolates not susceptible to ceftazidime-avibactam, the nonsusceptibility of half could be explained by their possession of genes encoding metallo-β-lactamases. The data reported here are consistent with results from other country-specific and regional surveillance studies and show that ceftazidime-avibactam demonstrates in vitro activity against globally collected clinical isolates of P. aeruginosa, including isolates that are resistant to ceftazidime and meropenem.

Assessment of Treatment of Community Acquired Severe Pneumonia by Two Different Antibiotics

INTRODUCTION

Pneumonia is common presentation in the emergency room and is still a cause of morbidity and mortality. The rationale of this study was to test the trend of paediatricians to achieve rapid response facing severe pneumonia, the lack of agreed on plan for the management of community acquired pneumonia (CAP) and the few experiences regarding injectable form of β-lactam antimicrobial.

MATERIALS AND METHODS

This is a prospective case control study, purposive randomized sampling, three patients were excluded since their information was incomplete, 132 patients were randomly divided into groups, one group named control group (penicillin according to the guidelines of WHO 2013), 33 patients; second group treated by β-lactam inhibitors (Augmentin IV) 50 patients; and third group treated by 3(rd) generation cephalosporin (ceftriaxone) 49 patients. The study was conducted at the main tertiary care and paediatrics teaching hospital in Khartoum capital of Sudan. The study was completed within the duration from 2010 to 2011.

RESULTS

Both group showed more or less similar results regarding response, as well as the failure rate however, the Augmentin and ceftriaxone groups showed a little bit better survival than the control group.

CONCLUSION

Antibiotics decrease the mortality rate among the pneumonia patients provided that it is given early in the disease.

Imaging bacteria with radiolabelled quinolones, cephalosporins and siderophores for imaging infection: a systematic review

Bacterial infections are still one of the main causes of patient morbidity and mortality worldwide. Nowadays, many imaging techniques, like computed tomography or magnetic resonance imaging, are used to identify inflammatory processes, but, although they recognize anatomical modifications, they cannot easily distinguish bacterial infective foci from non bacterial infections. In nuclear medicine, many efforts have been made to develop specific radiopharmaceuticals to discriminate infection from sterile inflammation. Several compounds (antimicrobial peptides, leukocytes, cytokines, antibiotics…) have been radiolabelled and tested in vitro and in vivo, but none proved to be highly specific for bacteria. Indeed factors, including the number and strain of bacteria, the infection site, and the host condition may affect the specificity of tested radiopharmaceuticals. Ciprofloxacin has been proposed and intensively studied because of its easy radiolabelling method, broad spectrum, and low cost, but at the same time it presents some problems such as low stability or the risk of antibiotic resistance. Therefore, in the present review studies with ciprofloxacin and other radiolabelled antibiotics as possible substitutes of ciprofloxacin are reported. Among them we can distinguish different classes, such as cephalosporins, fluoroquinolones, inhibitors of nucleic acid synthesis, inhibitors of bacterial cell wall synthesis and inhibitors of protein synthesis; then also others, like siderophores or maltodextrin-based probes, have been discussed as bacterial infection imaging agents. A systematic analysis was performed to report the main characteristics and differences of each antibiotic to provide an overview about the state of the art of imaging infection with radiolabelled antibiotics.

A fatal adverse effect of cefazolin administration: severe brain edema in a patient with multiple meningiomas

Cefazolin is commonly administered before surgery as a prophylactic antibiotic. Hypersensitivity to cefazolin is not uncommon, and the symptoms mostly include urticaria, skin reaction, diarrhea, vomiting, and transient neutropenia, which are rarely life threatening. We present a rare case of fatal cefazolin hypersensitivity in a female who was diagnosed with multiple meningiomas and scheduled for craniotomy and tumor removal. Immediately after cefazolin IV administration, the patient developed acute hypertensive crisis, which resolved within 10 minutes after the treatment. This was followed by unexplained metabolic acidosis. The patient then developed severe brain edema 100 minutes later. The patient had facial edema when her face was exposed for the next 30 minutes. A computed tomography scan revealed global brain edema with herniation. She was admitted to the intensive care unit for symptomatic treatment and died 10 days after surgery from multiorgan failure. The serum IgE level was very high (734 IU/mL). Single-dose administration of cefazolin for surgical prophylaxis may lead to rare, fatal adverse reaction. The warning signs are sudden, unexplained metabolic acidosis, hypertensive crisis, tachycardia, and facial angioedema predominating with or without cutaneous symptoms like urticaria.

A new antibiotic regimen treats and prevents intra-amniotic inflammation/infection in patients with preterm PROM

OBJECTIVES

To determine whether a new antibiotic regimen could reduce the frequency of intra-amniotic inflammation/infection in patients with preterm PROM.

STUDY DESIGN

This retrospective cohort study was conducted to evaluate the effect of antibiotics on the frequency of intra-amniotic inflammation/infection based on the results of follow-up transabdominal amniocenteses from 89 patients diagnosed with preterm PROM who underwent serial amniocenteses. From 1993-2003, ampicillin and/or cephalosporins or a combination was used ("regimen 1"). A new regimen (ceftriaxone, clarithromycin and metronidazole) was used from 2003-2012 ("regimen 2"). Amniotic fluid was cultured and matrix metalloproteinase-8 (MMP-8) concentrations were measured.

RESULTS

(1) The rates of intra-amniotic inflammation and intra-amniotic inflammation/infection in patients who received regimen 2 decreased during treatment from 68.8% to 52.1% and from 75% to 54.2%, respectively. In contrast, in patients who received regimen 1, the frequency of intra-amniotic inflammation and infection/inflammation increased during treatment (31.7% to 55% and 34.1% to 58.5%, respectively); and (2) intra-amniotic inflammation/infection was eradicated in 33.3% of patients who received regimen 2, but in none who received regimen 1.

CONCLUSION

The administration of ceftriaxone, clarithromycin and metronidazole was associated with a more successful eradication of intra-amniotic inflammation/infection and prevented secondary intra-amniotic inflammation/infection more frequently than an antibiotic regimen which included ampicillin and/or cephalosporins in patients with preterm PROM.

A new anti-microbial combination prolongs the latency period, reduces acute histologic chorioamnionitis as well as funisitis, and improves neonatal outcomes in preterm PROM

OBJECTIVE

Antibiotic administration is a standard practice in preterm premature rupture of membranes (PROM). Specific anti-microbial agents often include ampicillin and/or erythromycin. Anaerobes and genital mycoplasmas are frequently involved in preterm PROM, but are not adequately covered by antibiotics routinely used in clinical practice. Our objective was to compare outcomes of PROM treated with standard antibiotic administration versus a new combination more effective against these bacteria.

STUDY DESIGN

A retrospective study compared perinatal outcomes in 314 patients with PROM <34 weeks receiving anti-microbial regimen 1 (ampicillin and/or cephalosporins; n = 195, 1993-2003) versus regimen 2 (ceftriaxone, clarithromycin and metronidazole; n = 119, 2003-2012). Intra-amniotic infection/inflammation was assessed by positive amniotic fluid culture and/or an elevated amniotic fluid MMP-8 concentration (>23 ng/mL).

RESULTS

(1) Patients treated with regimen 2 had a longer median antibiotic-to-delivery interval than those with regimen 1 [median (interquartile range) 23 d (10-51 d) versus 12 d (5-52 d), p < 0.01]; (2) patients who received regimen 2 had lower rates of acute histologic chorioamnionitis (50.5% versus 66.7%, p < 0.05) and funisitis (13.9% versus 42.9%, p < 0.001) than those who had received regimen 1; (3) the rates of intra-ventricular hemorrhage (IVH) and cerebral palsy (CP) were significantly lower in patients allocated to regimen 2 than regimen 1 (IVH: 2.1% versus 19.0%, p < 0.001 and CP: 0% versus 5.7%, p < 0.05); and (4) subgroup analysis showed that regimen 2 improved perinatal outcomes in pregnancies with intra-amniotic infection/inflammation, but not in those without intra-amniotic infection/inflammation (after adjusting for gestational age and antenatal corticosteroid administration).

CONCLUSION

A new antibiotic combination consisting of ceftriaxone, clarithromycin, and metronidazole prolonged the latency period, reduced acute histologic chorioamnionitis/funisitis, and improved neonatal outcomes in patients with preterm PROM. These findings suggest that the combination of anti-microbial agents (ceftriaxone, clarithromycin, and metronidazole) may improve perinatal outcome in preterm PROM.

Identification and Characterization of Cefazolin-Induced Liver Injury

BACKGROUND & AIMS

Cephalosporin antibiotics are popular because they have a broad spectrum of activity and are generally well tolerated; however, cephalosporin-induced liver injury is considered rare. We describe a new syndrome associated with a single intravenous dose of cefazolin and the clinical features of cephalosporin-induced liver injury.

METHODS

The Drug-Induced Liver Injury (DILI) Network collected detailed clinical data on 1212 patients with DILI between 2004 and 2012. We analyzed data from 41 patients in whom cephalosporins were implicated as primary agents of liver disease; 33 formally were adjudicated as having cephalosporin-induced DILI.

RESULTS

Nineteen patients developed clinically apparent DILI after a single intravenous dose of cefazolin. All patients developed self-limited liver injury 3 to 23 days after receiving cefazolin during surgery-often during a minor outpatient procedure. The latency period was 20 days. Clinical features included itching, jaundice, nausea, fever, and rash. Laboratory abnormalities included a mixed or cholestatic pattern of serum enzyme increases. We identified 14 more patients with DILI attributed to other cephalosporins (5 first-generation, 2 second-generation, 6 third-generation, and 1 fourth-generation agent). Although latency and injury patterns were similar for cefazolin and other cephalosporins, the other cephalosporins were associated with more severe courses of injury, including 2 deaths from liver failure.

CONCLUSIONS

DILI can develop after a single dose of cefazolin. It is characterized by a latency period of 1 to 3 weeks after exposure, a cholestatic biochemical pattern, and a self-limited moderate to severe clinical course. Other cephalosporins can cause a similar but more severe injury.

Pharmacokinetics and penetration of ceftazidime and avibactam into epithelial lining fluid in thigh- and lung-infected mice

Ceftazidime and the β-lactamase inhibitor avibactam constitute a new, potentially highly active combination in the battle against extended-spectrum-β-lactamase (ESBL)-producing bacteria. To determine possible clinical use, it is important to know the pharmacokinetic profiles of the compounds related to each other in plasma and the different compartments of infection in experimentally infected animals and in humans. We used a neutropenic murine thigh infection model and lung infection model to study pharmacokinetics in plasma and epithelial lining fluid (ELF). Mice were infected with ca. 10(6) CFU of Pseudomonas aeruginosa intramuscularly into the thigh or intranasally to cause pneumonia and were given 8 different (single) subcutaneous doses of ceftazidime and avibactam in various combined concentrations, ranging from 1 to 128 mg/kg of body weight in 2-fold increases. Concomitant samples of serum and bronchoalveolar lavage fluid were taken at up to 12 time points until 6 h after administration. Pharmacokinetics of both compounds were linear and dose proportional in plasma and ELF and were independent of the infection type, with estimated half-lives (standard deviations [SD]) in plasma of ceftazidime of 0.28 (0.02) h and of avibactam of 0.24 (0.04) h and volumes of distribution of 0.80 (0.14) and 1.18 (0.34) liters/kg. The ELF-plasma (area under the concentration-time curve [AUC]) ratios (standard errors [SE]) were 0.24 (0.03) for total ceftazidime and 0.27 (0.03) for unbound ceftazidime; for avibactam, the ratios were 0.20 (0.02) and 0.22 (0.02), respectively. No pharmacokinetic interaction between ceftazidime and avibactam was observed. Ceftazidime and avibactam showed linear plasma pharmacokinetics that were independent of the dose combinations used or the infection site in mice. Assuming pharmacokinetic similarity in humans, this indicates that similar dose ratios of ceftazidime and avibactam could be used for different types and sites of infection.

Canine superficial bacterial pyoderma: evaluation of skin surface sampling methods and antimicrobial susceptibility of causal Staphylococcus isolates

OBJECTIVE

To evaluate three easily performed methods of skin surface sampling for bacterial culture of Staphylococcus isolates obtained from dogs with superficial bacterial pyoderma (SBP) presenting to two veterinary teaching hospitals in Sydney, Australia, and to determine the antimicrobial susceptibility of isolates.

DESIGN

Prospective study of 27 dogs with SBP. Cytologically confirmed SBP lesions were sampled for bacterial culture using a dry cotton swab, a saline-moistened cotton swab and a skin surface scraping. Isolates were identified by standard discriminatory phenotypic and biochemical analyses, and confirmed using matrix-assisted laser desorption ionisation time of flight mass spectrometry (MALDI-TOF MS). Susceptibilities to 14 antimicrobials were determined by disk diffusion and by detection of the mecA gene using PCR. Sampling methods were compared according to bacterial yield, antibiograms and bacterial phenotypic analysis. Location of causative bacteria was evaluated via 8-mm punch skin biopsies using haematoxylin and eosin, Gram-Twort and Giemsa staining, and fluorescence in situ hybridisation (FISH).

RESULTS

Staphylococcus sp. were isolated from lesions in all dogs, either S. pseudintermedius (24 dogs) or S. schleiferi (3 dogs). Susceptibility was highest to cephalexin (96%) and amoxycillin clavulanate (96%). Methicillin resistance assessed by mecA real-time PCR and phenotypic oxacillin resistance was found in one dog (4.3%). Routine histology and FISH revealed bacteria within superficial stratum corneum.

CONCLUSION

Staphylococcal isolates from canine SBP demonstrated high susceptibility to common empirical antimicrobials. Histological techniques confirmed presence of bacteria at superficial sites, likely to be accessed by the sampling techniques. The three techniques afforded similar results and may be equally suitable for obtaining samples for culture.

Natural products in medicine: transformational outcome of synthetic chemistry

This review brings to the forefront key synthetic modifications on natural products (NPs) that have yielded successful drugs. The emphasis is placed on the power of targeted chemical transformations in enhancing the therapeutic value of NPs through optimization of pharmacokinetics, stability, potency, and/or selectivity. Multiple classes of NPs such as macrolides, opioids, steroids, and β-lactams used to treat a variety of conditions such as cancers, infections, inflammation are exemplified. Molecular modeling or X-ray structures of NP/protein complexes supporting the observed boost in therapeutic value of the modified NPs are also discussed. Significant advancement in synthetic chemistry, in structure determination, and in the understanding of factors controlling pharmacokinetics can now better position drug discovery teams to undertake NPs as valuable leads. We hope that the beneficial NPs synthetic modifications outlined here will reignite medicinal chemists' interest in NPs and their derivatives.

Avibactam reverts the ceftazidime MIC90 of European Gram-negative bacterial clinical isolates to the epidemiological cut-off value

OBJECTIVES

Ceftazidime-avibactam consists of the beta-lactam ceftazidime and the novel non-beta-lactam beta-lactamase inhibitor avibactam. The effect of avibactam on the ceftazidime MIC frequency distribution of Gram-negative European clinical isolates was observed and compared to European Committee for Antimicrobial Susceptibility Testing (EUCAST) MIC frequency distributions and epidemiological cut-off values (ECOFFs) listed for ceftazidime.

METHODS

Ceftazidime and ceftazidime-avibactam MICs were determined using Clinical and Laboratory Standards Institute (CLSI) reference broth microdilution methods for Pseudomonas aeruginosa, Escherichia coli, Klebsiella spp., Serratia spp., Enterobacter spp., and Proteus mirabilis isolates collected from medical centres in Europe during 2009.

RESULTS

The MIC(90) values for ceftazidime and ceftazidime-avibactam against P. aeruginosa isolates from a 2009 European surveillance programme were >32 and 8 mg/l, respectively. That is, the presence of avibactam reverted the ceftazidime MIC(90) for P. aeruginosa to the ECOFF. Similarly, the MIC(90) values for ceftazidime against E. coli, Klebsiella spp., Serratia spp., and P. mirabilis were also reduced to the ECOFF by the presence of avibactam. Avibactam reduced the ceftazidime MIC(90) value against collected Enterobacter spp. to 1 mg/l (>32-fold reduction). No ECOFF has been defined for Enterobacter spp. however, it is 1 mg/l for Enterobacter aerogenes and Enterobacter cloacae.

CONCLUSIONS

The presence of avibactam reverted the ceftazidime MIC(90) for Gram-negative bacteria to the ECOFF.

Ceftazidime for respiratory infections

INTRODUCTION

Ceftazidime is a third-generation cephalosporin that has activity against Gram-negative bacilli, including Pseudomonas aeruginosa. The increasing prevalence of antimicrobial resistance and the limited number of antimicrobial agents in development have necessitated a review of the current status of treatments involving ceftazidime.

AREAS COVERED

This review focuses on studies examining the in vitro antibacterial activity of ceftazidime against recent clinical isolates and recent randomized controlled trials studying the clinical efficacy of ceftazidime, and discusses strategies for the optimal use of ceftazidime for treating respiratory tract infections, mainly hospital-acquired pneumonia (HAP).

EXPERT OPINION

Although ceftazidime remains an important option for HAP treatment, its role as an effective antimicrobial agent has been compromised by the sharp increase in resistance rates over the last decade, especially in P. aeruginosa and Acinetobacter baumannii. To maintain or improve the clinical use of ceftazidime in patients with severe HAP, it will be essential to gain a thorough understanding of local resistance patterns, reserve ceftazidime use when pathogens are susceptible to other third-generation cephalosporins, optimize ceftazidime therapy using prolonged or continuous infusion, determine the effectiveness of the combination of ceftazidime with inhibitors of broad-spectrum β-lactamases and role of combination therapy for P. aeruginosa infections, and judiciously use antimicrobial agents through individualization of antimicrobial therapy for HAP.

Cefotaxime-induced near-fatal anaphylaxis in a neonate: A case report and review of literature

A case of 7-day-old male neonate with cefotaxime-induced near-fatal anaphylaxis is being reported. Child was started on intravenous cefotaxime on day 3 of life in view of early-onset sepsis with pneumonia, following which there was clinical improvement. Child was then shifted out of intensive care to general ward for completion of antibiotic course. One day prior to the planned discharge, child suddenly developed poor sensorium, flaccidity, apnea, and cyanosis within seconds of receiving intravenous cefotaxime and was found to have bradypnea with bradycardia. Prompt resuscitation was carried out with artificial ventilation, adrenaline, and steroids. Spontaneous breathing reappeared and the clinical condition improved.