Classification of cephalosporins

Biochemical and Haematological Predictors of Reduced Neutrophil Granulocyte Count associated with Intravenous Ceftriaxone Treatment

Background:

Intravenous treatment with ceftriaxone, a commonly used third-generation cephalosporin, is associated with a risk of the potentially fatal side-effect of neutropenia.

Objective:

The first systematic study to determine whether six to 12 days’ intravenous ceftriaxone treat-ment is associated with a reduction in the neutrophil count and the extent to which biochemical and/or haematological parameters routinely measured at baseline predict such a fall.

Method:

Baseline and follow-up haematological and biochemical blood indices were measured in 86 pa-tients (mean age 39.4 years; 55 female) receiving 2 g intravenous ceftriaxone daily.

Results:

At follow-up, the mean (standard error) neutrophil count had fallen from 3.93 × 109 (0.16 × 109) L-1 to 3.15 × 109 (0.15 × 109) L-1 (p < 0.000001). This reduction was predictable according to the following multifactor linear regression model: (baseline neutrophil count (× 109 L-1)) – (follow-up neu-trophil count (× 109 L-1)) = 76 + 159.2(baseline haematocrit) – 14.5(baseline red blood cell count (× 1012 L-1)) – 0.724(baseline mean corpuscular volume (fL)) + 0.474(baseline neutrophil count (× 109 L-1)) + 0.0448(baseline total iron binding capacity (μM)) + 7.15(baseline calcium ion concentration (mM)) – 13.2(baseline corrected calcium ion concentration (mM)) + 0.0166(baseline alkaline phosphatase (IU L-1)). The residuals were normally distributed and model testing by random partition of the original data into two parts, with training of the model using the first part and model testing with the second part, gave highly satisfactory results.

Conclusion:

Intravenous ceftriaxone treatment is associated with a fall in neutrophils, which can be pre-dicted by routine baseline blood indices

Drug utilization review of cephalosporins in a secondary care hospital in United Arab Emirates

Background Cephalosporins are one of the most commonly used antibiotics in United Arab Emirates (UAE). Few studies have been carried out to evaluate the antibiotic utilization pattern in UAE in spite of the obvious increase in cephalosporins resistance during the past decade. Objective To assess the prescriptions pattern of cephalosporins among physicians at a secondary care hospital in Ras Al Khaimah, UAE. Method This observational prospective study was carried out during October 2013 to April 2014. The data of in patients were documented in the predesigned patient profile form and was analyzed for patient's, drug's and drug's therapy related parameters. Results The 3rd generation cephalosporins constituted 83.6 % of the prescriptions, with ceftriaxone being the most commonly used one (81.1 %). They were mainly prescribed for the treatment of the lower respiratory tract infections (60.2 %). Seven (3.5 %) different ADRs linked to cephalosporin use were observed ranging from oral thrush to clostridium difficile infection. A total of 1039 antimicrobial and nonantimicrobial medications were prescribed concomitantly with cephalosporins. Conclusion The 3rd generation cephalosporins were commonly prescribed by parenteral route. Thus, there is a strong need for rationalizing their use to preserve their efficacy and prevent the development of resistance in the region.

Pharmacokinetics of cephalosporins in the neonate: a review

The aim of this work was to review the published data on the pharmacokinetics of cephalosporins in neonates to provide a critical analysis of the literature as a useful tool for physicians. The bibliographic search was performed for articles published up to December 3, 2010, using PubMed. In addition, the book Neofax: A Manual of Drugs Used in Neonatal Care by Young and Mangum was consulted. The cephalosporins are mainly eliminated by the kidneys, and their elimination rates are reduced at birth. As a consequence, clearance is reduced and t1/2 is more prolonged in the neonate than in more mature infants. The neonate's substantial body water content creates a large volume of distribution (Vd) of cephalosporins, as these drugs are fairly water soluble. Postnatal development is an important factor in the maturation of the neonate, and as postnatal age proceeds, the clearance of cephalosporins increases. The maturation of the kidney governs the pharmacokinetics of cephalosporins in the infant. Clearance and t1/2 are influenced by development, and this must be taken into consideration when planning a cephalosporin dosage regimen for the neonate.

Ceftaroline fosamil: a novel broad-spectrum cephalosporin with expanded anti-Gram-positive activity

Ceftaroline fosamil is a novel cephalosporin with broad-spectrum activity against Gram-positive pathogens, including methicillin-resistant Staphylococcus aureus (MRSA) and multidrug-resistant Streptococcus pneumoniae, and common Gram-negative organisms. The activity of ceftaroline against MRSA is attributed to its ability to bind to penicillin-binding protein (PBP) 2a with high affinity and inhibit the biochemical activity of PBP 2a more efficiently than other presently available β-lactams. The activity of ceftaroline against MRSA and the β-haemolytic streptococci makes it an attractive monotherapy agent for the treatment of complicated skin and skin structure infections (cSSSIs). Recent profiling and surveillance studies have shown that ceftaroline is active against contemporary skin pathogens collected from US and European medical centres in 2008. The mean free drug %T  >  MIC (percentage of time the drug concentration remains above the MIC) needed for stasis ranged from 26% for S. aureus to 39% for S. pneumoniae in the murine thigh infection model. Pharmacokinetic and pharmacodynamic target attainment predictions for 600 mg of ceftaroline fosamil every 12 h showed that the mean %T  >  MICs for which plasma free-drug concentrations exceeded an MIC of 1 and 2 mg/L were 71% and 51% of the dosing interval, respectively. For a 40% T  >  MIC target, the predicted attainments for infections due to pathogens for which ceftaroline MICs were 1 or 2 mg/L were 100% and 90%, respectively. Clinical and microbiological successes of ceftaroline fosamil in treating cSSSIs were demonstrated in two Phase III clinical studies, in which 96.8% of all baseline cSSSI isolates from the microbiologically evaluable population were inhibited by ceftaroline at ≤ 2 mg/L. Ceftaroline fosamil is a promising broad-spectrum agent for the treatment of cSSSIs.

Oral cephalosporins: current perspectives

Oral cephalosporins had been, for years, a small group of compounds belonging to the first or second-generation cephalosporins, with a limited antimicrobial spectrum. New oral first-generation cephalosporins include cefprozil and loracarbef, similar to cefadroxil and cefaclor, respectively, with activity similar to cefaclor but with pharmacokinetic improvements. Second-generation oral cephalosporins are esters of already available cephalosporins, and third-generation oral cephalosporins include a number of drugs whose activity is similar to available parenteral drugs, showing pharmacokinetic advantages and, some of them, better resistance to hydrolysis mediated by extended wide-spectrum beta-lactamases. They may be a good alternative against mild to moderate ENT infections, UTIs, STDs, lower respiratory tract and skin and soft tissue infections, mainly in the outpatient setting.

Cephalosporin chemical reactivity and its immunological implications

PURPOSE OF REVIEW

The aim of this article is to analyze the chemical reactivity of cephalosporins resulting in the epitope responsible for recognition by IgE antibodies and to establish the basis of the allergenicity.

RECENT FINDINGS

Increasing evidence supports the role of cephalosporins in IgE hypersensitivity reactions. Third and fourth generation cephalosporins appear to be more involved in specific IgE reactions and often no cross-reactivity with traditional benzyl penicillin determinants exists. In some instances selective responses to unique cephalosporins occur and in others common side-chain similarities exist.

SUMMARY

Lack of knowledge of the exact chemical structure of cephalosporin antigenic determinants has hindered clinical interpretation of allergic reactions to these drugs and hampered understanding of the specific recognition by IgE molecules of these determinants. Data indicate that R2 is not present in the final conjugate and that recognition by IgE antibodies is mainly directed to the R1 acyl side chain and to the beta-lactam fragment that remains linked to the carrier protein in the cephalosporin conjugation process.

Comparison of several methods used for the determination of cephalosporins. Analysis of cephalexin in pharmaceutical samples

The precision of UV absorbance of intact and acid degraded cephalosporins, ninhydrin, high performance liquid chromatography and iodometric methods used for analysis of cefoxitin, cefotaxime, cephazolin and cephalexin were compared. To obtain the calibration graphs the analytical signal used were: absorbance, first derivative absorbance, second derivative absorbance and H-point Standard Additions Method by using absorbance values at two selected wavelengths as analytical signal. These methods and calibration graphs were also used for the determination of cephalexin in pharmaceutical samples.

Improved outcomes following a change in the cephalosporin policy in an acute hospital

This paper evaluates the effect of a policy change on the use of cephalosporins in an acute hospital. The main outcome measures (timeliness and appropriateness of administration of antibiotics, infection rates, length of hospital stay and readmission rate) showed significant improvements. The change of policy from three doses a day to a once-a-day dose improved the prescribing, preparation and administration of all cephalosporins in the short term and resulted in a shorter length of hospital stay, lower readmission rates and a reduction in bacteriologically confirmed infections. This pilot study could be used as the basis for further research.

Determination of third-generation cephalosporins by high-performance liquid chromatography in connection with pharmacokinetic studies

The third-generation cephalosporins are semisynthetic beta-lactam antibiotics, including several oral and parental agents with extended activity against Gram-negative pathogens. They are generally determined either by microbiological techniques or by high-performance liquid chromatography (HPLC). The major drawback or bioassays is the lack of specificity, especially when a biotransformation of the cephalosporin molecule leads to active metabolites, or when the antibacterial therapy is based on association with drugs. Thus, for many years, numerous reversed-phase HPLC procedures have been proposed to overcome these difficulties. This review presents different HPLC methods proposed for the quantification in biological fluids of fourteen third-generation cephalosporins, ranged between parenteral and oral compounds. The sensitivity and specificity of these chromatographic procedures are discussed with regard to the pharmacokinetic properties of the antibiotics studied.

Pharmacokinetics of intravenously and intramuscularly administered cefepime in infants and children

The pharmacokinetic characteristics of cefepime were determined after first dose (n = 35) and again under steady-state conditions (n = 31) with a group of 37 infants and children. In eight subjects, a cefepime dose given by intramuscular injection was substituted for an intravenous dose, and disposition characteristics were studied again. Study subjects ranged in age from 2.1 months to 16.4 years, and all had normal renal function. Each patient received 50 mg of cefepime/kg of body weight intravenously every 8 h, up to a total maximum individual dose of 2 g. With the exception of one study patient who received a single cefepime dose for surgical prophylaxis, the patients received cefepime for 2 to 13 days. Elimination half-life (t1/2), steady-state volume of distribution, total body clearance, and renal clearance after first dose administration averaged 1.7 h, 0.35 liter/kg, and 3.1 and 1.9 ml/min/kg, respectively. Although cefepime t1/2 and mean residence time (MRT) were slightly longer for subjects <6 months of age than for older subjects, no differences in cefepime disposition characteristics between first dose and steady-state evaluations were observed. t1/2 (1.8 versus 1.9 h) and MRT (2.3 versus 3.2 h) were slightly prolonged after intramuscular administration, reflecting the influence of absorption from the intramuscular injection site on cefepime elimination. Bioavailability after intramuscular administration averaged 82% (range, 61 to 124%). Fifty-seven percent of the first dose and 88.9% of the last dose were recovered as unchanged drug in urine over the 8- and 24-h sampling periods, respectively. These pharmacokinetic data support a single cefepime dosing strategy for patients > or =2 months of age. The integration of the cefepime pharmacokinetic data generated in our study with the MICs for important pathogens responsible for infections in infants and children supports the administration of a dose of 50 mg of cefepime/kg every 12 h for patients > or =2 months of age to treat infections caused by pathogens for which cefepime MICs are < or =8 mg/liter.

beta-Lactamases in laboratory and clinical resistance

beta-Lactamases are the commonest single cause of bacterial resistance to beta-lactam antibiotics. Numerous chromosomal and plasmid-mediated types are known and may be classified by their sequences or phenotypic properties. The ability of a beta-lactamase to cause resistance varies with its activity, quantity, and cellular location and, for gram-negative organisms, the permeability of the producer strain. beta-Lactamases sometimes cause obvious resistance to substrate drugs in routine tests; often, however, these enzymes reduce susceptibility without causing resistance at current, pharmacologically chosen breakpoints. This review considers the ability of the prevalent beta-lactamases to cause resistance to widely used beta-lactams, whether resistance is accurately reflected in routine tests, and the extent to which the antibiogram for an organism can be used to predict the type of beta-lactamase that it produces.

Cephalosporins--cefotaxime 10 years later, a major drug with continued use

Cefotaxime has in the past decade proved to be a most useful agent. It has established the efficacy and safety suggested in the early in vitro, pharmacological and clinical papers. It remains an excellent agent to treat many community and hospital-acquired respiratory infections, urinary tract infections, meningitis, particularly in pediatrics, spontaneous bacterial peritonitis and selected abdominal and gynecological infections.

Pathophysiologic basis for the use of third-generation cephalosporins

After 10 years of use, the third-generation cephalosporins remain excellent antibiotics. They have superior activity against selected streptococcal species compared with other cephalosporins, and superior activity against Haemophilus, Neisseria, Branhamella, and other less common oral gram-negative aerobic species. Despite a very broad spectrum of activity, the third-generation cephalosporins, like all other cephalosporins, have only poor activity against enterococci, Listeria, Corynebacterium jekeium, and methicillin-resistant staphylococci. Over the past 10 years, the activity of the third-generation cephalosporins against Escherichia coli, Klebsiella, Proteus, Providencia, Serratia, Haemophilus, and Neisseria has remained excellent. Equally as important, though perhaps less well recognized, is the activity of some of these agents against mouth anaerobic species and the anaerobic Bacteroides and Clostridium spp. of the pelvic area. At present, there are two main threats to the continued use of the third-generation cephalosporins. These are the increasing number of infections due to Enterobacter spp., which constitutively produce large amounts of a beta-lactamase that hydrolyzes cephalosporins, and the recent appearance of Klebsiella spp. in many parts of the world that possess new plasmid-mediated beta-lactamases that destroy cefotaxime, ceftazidime, and related third-generation parenteral cephalosporins. Correlation of pharmacologic properties with in vitro activity provides information as to reasonable dosage regimens for the third-generation cephalosporins. For most serious infections cefotaxime, ceftizoxime, and ceftazidime should be given three times a day provided that the patient has relatively normal renal function. Ceftriaxone can be administered once daily in less severe infections. The use of lower doses or less frequent dosing with cefotaxime, ceftizoxime, or ceftazidime is recommended in aged patients whose renal function is impaired. The unique interaction of cefotaxime with its active metabolite, desacetylcefotaxime, allows cefotaxime to be administered less frequently than three times a day in selected anaerobic infections. Correlation of the antibacterial activity and pharmacology of cephalosporins will help us to tailor their use more appropriately, so that the third-generation cephalosporins will remain useful antimicrobial agents for a further decade.