Oral β-lactams applied to uncomplicated infections of skin and skin structures

Prescribed drugs containing nitrogen heterocycles: an overview

Heteroatoms as well as heterocyclic scaffolds are frequently present as the common cores in a plethora of active pharmaceuticals natural products. Statistically, more than 85% of all biologically active compounds are heterocycles or comprise a heterocycle and most frequently, nitrogen heterocycles as a backbone in their complex structures. These facts disclose and emphasize the vital role of heterocycles in modern drug design and drug discovery. In this review, we try to present a comprehensive overview of top prescribed drugs containing nitrogen heterocycles, describing their pharmacological properties, medical applications and their selected synthetic pathways. It is worth mentioning that the reported examples are actually limited to current top selling drugs, being or containing N-heterocycles and their synthetic information has been extracted from both scientific journals and the wider patent literature.

The effects of the time of intranasal splinting on bacterial colonization, postoperative complications, and patient discomfort after septoplasty operations

Introduction

The main reason for nasal tampon placement after septoplasty is to prevent postoperative hemorrhage, while the secondary purpose is internal stabilization after operations involving the cartilaginous-bony skeleton of the nose. Silicone intranasal splints are as successful as other materials in controlling postoperative hemorrhages of septal origin. The possibility of leaving the splints intranasally for extended periods helps stabilize the septum in the midline. However, there is nothing in the literature about how long these splints can be retained inside the nasal cavity without increasing the risk of infection, postoperative complications, and patient discomfort.

Objective

The current study aimed to evaluate the association between the duration of intranasal splinting and bacterial colonization, postoperative complications, and patient discomfort.

Methods

Patients who had undergone septoplasty were divided into three groups according to the day of removal of the silicone splints. The splints were removed on the fifth, seventh, and tenth postoperative days. The removed splints were microbiologically cultured. Early and late complications were assessed, including local and systemic infections, tissue necrosis, granuloma formation, mucosal crusting, synechia, and septal perforation. Postoperative patient discomfort was evaluated by scoring the levels of pain and nasal obstruction.

Results

No significant difference was found in the rate of bacterial colonization among the different groups. Decreased mucosal crusting and synechia were detected with longer usage intervals of intranasal silicone splints. Postoperative pain and nasal obstruction were also diminished by the third postoperative day.

Conclusions

Silicone splints were well tolerated by the patients and any negative effects on postoperative patient comfort were limited. In fact, prolonged splint usage intervals reduced late complications. Long-term silicone nasal splint usage is a reliable, effective, and comfortable method in patients with excessive mucosal damage and in whom long-term stabilization of the bony and cartilaginous septum is essential.

Iontophoresis of amoxicillin and cefuroxime: rapid therapeutic concentrations in skin

CONTEXT

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSION

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

Treatment outcomes of secondarily impetiginized pediatric atopic dermatitis lesions and the role of oral antibiotics

Patients with atopic dermatitis (AD) are predisposed to infection with Staphylococcus aureus, which worsens their skin disease; it has been postulated that the lack of antimicrobial peptides due to aberrant allergic inflammation in skin with AD could mediate this enhanced bacterial susceptibility. We sought to characterize the amounts of S. aureus and biological products found in infected AD lesions and whether treatment with topical corticosteroids and oral cephalexin as the only antimicrobial improved outcomes. Fifty-nine children with clinically and S. aureus-positive impetiginized lesions of AD were enrolled in this study. A lesion was graded clinically using the Eczema Area and Severity Index, and wash fluid was obtained from the lesion for quantitative bacterial culture and antibiotic sensitivities and measurement of bacterial products and cytokines. Subjects were re-evaluated 2 weeks after treatment. Improvement in the clinical and inflammatory characteristics of impetiginized lesions were noted, even in the 15% of lesions infected with Methicillin-resistant S. aureus (MRSA). In a subgroup of subjects whose lesions did not contain S. aureus 2 weeks after initiating treatment, beta-defensin levels were higher at both visits than in normal skin. Treatment of uncomplicated impetiginized pediatric AD with topical corticosteroids and cephalexin results in significant clinical improvement, even in subjects infected with MRSA. We propose that the inhibition of abnormal inflammation by the treatment regimen, resulting in the high levels of defensins, is involved in the improvement of AD and that systemic antibiotics do not appear to be necessary in secondary impetiginized AD.

Incidence of methicillin-resistant Staphylococcus aureus in postpartum breast abscesses

OBJECTIVE

The study objective is to determine the incidence of methicillin-resistant Staphylococcus aureus (MRSA) in postpartum breast abscesses in two Houston, TX, area hospitals.

STUDY DESIGN AND METHODS

This is a retrospective chart review of women hospitalized for postpartum breast abscesses at Woman's Hospital of Texas and Memorial Hermann Hospital between January 1, 2000 and December 31, 2006. Patients were identified by searching admission records for ICD-9 codes related to breast abscesses. Demographic characteristics, medical history, culture results, and pertinent procedures were recorded. Statistical analyses included the Fisher exact test for categorical data and Student's test for continuous variables.

RESULTS

Thirty-three postpartum abscesses were identified: 19 from Memorial Hermann Hospital and 14 from Woman's Hospital. MRSA and S. aureus were the only causative bacteria identified. Twelve of the 19 abscesses from Hermann Hospital were MRSA positive (63%), and nine of the 14 from Woman's Hospital were MRSA positive (64%). There were no statistically significant differences among women with MRSA abscesses versus those with S. aureus abscesses in terms of ethnicity, age, time to presentation, parity, insurance, or mode of delivery. Susceptibility patterns were consistent with community-acquired MRSA.

CONCLUSIONS

MRSA is a significant pathogen in postpartum breast abscesses in our population, and a high level of suspicion is warranted. Local susceptibility patterns should guide treatment. Empirical treatment of breast abscesses without first obtaining cultures should be discouraged.

Empiric antimicrobial therapy for pediatric skin and soft-tissue infections in the era of methicillin-resistant Staphylococcus aureus

OBJECTIVE

The goal was to compare the clinical effectiveness of monotherapy with beta-lactams, clindamycin, or trimethoprim-sulfamethoxazole in the outpatient management of nondrained noncultured skin and soft-tissue infections (SSTIs), in a methicillin-resistant Staphylococcus aureus (MRSA)-endemic region.

METHODS

A retrospective, nested, case-control trial was conducted with a cohort of patients from 5 urban pediatric practices in a community-acquired MRSA-endemic region. All subjects were treated as outpatients with oral monotherapy for nondrained noncultured SSTIs between January 2004 and March 2007. The primary outcome was treatment failure, defined as a drainage procedure, hospitalization, change in antibiotic, or second antibiotic prescription within 28 days.

RESULTS

Of 2096 children with nondrained noncultured SSTIs, 104 (5.0%) were identified as experiencing treatment failure and were matched to 480 control subjects. Compared with beta-lactam therapy, clindamycin was equally effective but trimethoprim-sulfamethoxazole was associated with an increased risk of failure. Other factors independently associated with failure included initial treatment in the emergency department, presence or history of fever, and presence of either induration or a small abscess.

CONCLUSIONS

Compared with beta-lactams, clindamycin monotherapy conferred no benefit, whereas trimethoprim-sulfamethoxazole was associated with an increased risk of treatment failure in a cohort of children with nondrained noncultured SSTIs who were treated as outpatients. Even in regions with endemic community-acquired MRSA, beta-lactams may still be appropriate, first-line, empiric therapy for children presenting with these infections.

Topical retapamulin in the management of infected traumatic skin lesions

Retapamulin is a novel semisynthetic pleuromutilin antibiotic specifically designed for use as a topical agent. The unique mode of action by which retapamulin selectively inhibits bacterial protein synthesis differentiates it from other nonpleuromutilin antibacterial agents that target the ribosome or ribosomal factors, minimizing the potential for target-specific cross-resistance with other antibacterial classes in current use. In vitro studies show that retapamulin has high potency against the Gram-positive bacteria (Staphylococcus aureus, Streptococcus pyogenes, and coagulase-negative staphylococci) commonly found in skin and skin-structure infections (SSSIs), including S. aureus strains with resistance to agents such as macrolides, fusidic acid, or mupirocin, and other less common organisms associated with SSSIs, anaerobes, and common respiratory tract pathogens. Clinical studies have shown that twice-daily topical retapamulin for 5 days is comparable to 10 days of oral cephalexin in the treatment of secondarily infected traumatic lesions. A 1% concentration of retapamulin ointment has been approved for clinical use as an easily applied treatment with a short, convenient dosing regimen for impetigo. Given the novel mode of action, low potential for cross-resistance with established antibacterial agents, and high in vitro potency against many bacterial pathogens commonly recovered from SSSIs, retapamulin is a valuable enhancement over existing therapeutic options.

Retapamulin: a review of its use in the management of impetigo and other uncomplicated superficial skin infections

Topical retapamulin (Altabax, Altargo) is the first pleuromutilin antibacterial approved for the treatment of uncomplicated superficial skin infections caused by Staphylococcus aureus (excluding meticillin-resistant S. aureus [MRSA]) and Streptococcus pyogenes in patients aged > or = 9 months. In the EU, retapamulin is indicated for use in patients with impetigo or with infected small lacerations, abrasions or sutured wounds (without abscesses); in the US, it is indicated for use in patients with impetigo. Retapamulin has a novel site of action on bacterial ribosomes. In clinical trials in patients with impetigo, topical retapamulin 1% ointment twice daily for 5 days (the approved regimen) was superior to placebo; treatment with retapamulin was noninferior to that with topical fusidic acid. In patients with secondarily infected traumatic lesions, treatment with retapamulin was noninferior to that with oral cefalexin, although the efficacy of retapamulin was reduced in patients with MRSA infections or superficial abscesses. Retapamulin was well tolerated in both paediatric and adult patients, and the majority of adverse events were of mild to moderate severity. Thus, the introduction of topical retapamulin 1% ointment extends the treatment options available in the management of impetigo and uncomplicated secondarily infected traumatic lesions.

Retapamulin: a semisynthetic pleuromutilin compound for topical treatment of skin infections in adults and children

Retapamulin is a semisynthetic pleuromutilin compound with in vitroactivity against Gram-positive bacteria, no cross-resistance to other classes of antimicrobial agents in current use and a low potential for development of resistance. A 1% ointment formulation has been developed for clinical use, and a placebo-controlled trial of impetigo in 210 patients produced significantly higher rates of clinical and microbiological success compared with placebo - 85.6 versus 52.1% and 91.2 versus 50.9%, respectively. Additional comparative studies in over 1900 patients showed noninferiority to topical fusidic acid and oral cephalexin and a low frequency of adverse events. In 2007, retapamulin was approved in the USA for topical treatment of impetigo caused by Streptococcus pyogenes and methicillin-susceptible Staphylococcus aureus, and in the EU for topical treatment of impetigo and infected wounds caused by S. pyogenes and S. aureus, with approvals including adults and children over 9 months of age.

Combination drugs, an emerging option for antibacterial therapy

The emerging and sustained resistance to antibiotics and the poor pipeline of new antibacterials is creating a major health issue worldwide. Bacterial pathogens are increasingly becoming resistant even to the most recently approved antibiotics. Few antibiotics are being approved by regulatory organizations, which reflects both the difficulty of developing such agents and the fact that antibiotic discovery programs have been terminated at several major pharmaceutical companies in the past decade. As a result, the output of the drug pipelines is simply not well positioned to control the growing army of resistant pathogens, although academic institutions and smaller companies are trying to fill that gap. An emerging option to fight such pathogens is combination therapy. Combinations of two antibiotics or antibiotics with adjuvants are emerging as a promising therapeutic approach. This article provides and discusses clinical and scientific challenges to support the development of combination therapy to treat bacterial infections.

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

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