Comparative effectiveness, safety and tolerance of mezlocillin and ticarcillin: a prospective randomized trail

Interventions for cellulitis and erysipelas

BACKGROUND

Cellulitis and erysipelas are now usually considered manifestations of the same condition, a skin infection associated with severe pain and systemic symptoms. A range of antibiotic treatments are suggested in guidelines.

OBJECTIVES

To assess the efficacy and safety of interventions for non-surgically-acquired cellulitis.

SEARCH STRATEGY

In May 2010 we searched for randomised controlled trials in the Cochrane Skin Group Specialised Register, the Cochrane Central Register of Controlled Trials in The Cochrane Library, MEDLINE, EMBASE, and the ongoing trials databases.

SELECTION CRITERIA

We selected randomised controlled trials comparing two or more different interventions for cellulitis.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data.

MAIN RESULTS

We included 25 studies with a total of 2488 participants. Our primary outcome 'symptoms rated by participant or medical practitioner or proportion symptom-free' was commonly reported. No two trials examined the same drugs, therefore we grouped similar types of drugs together.Macrolides/streptogramins were found to be more effective than penicillin antibiotics (Risk ratio (RR) 0.84, 95% CI 0.73 to 0.97). In 3 trials involving 419 people, 2 of these studies used oral macrolide against intravenous (iv) penicillin demonstrating that oral therapies can be more effective than iv therapies (RR 0.85, 95% CI 0.73 to 0.98).Three studies with a total of 88 people comparing a penicillin with a cephalosporin showed no difference in treatment effect (RR 0.99, 95% CI 0.68 to 1.43).Six trials which included 538 people that compared different generations of cephalosporin, showed no difference in treatment effect (RR 1.00, 95% CI 0.94 to1.06).We found only small single studies for duration of antibiotic treatment, intramuscular versus intravenous route, the addition of corticosteroid to antibiotic treatment compared with antibiotic alone, and vibration therapy, so there was insufficient evidence to form conclusions. Only two studies investigated treatments for severe cellulitis and these selected different antibiotics for their comparisons, so we cannot make firm conclusions.

AUTHORS' CONCLUSIONS

We cannot define the best treatment for cellulitis and most recommendations are made on single trials. There is a need for trials to evaluate the efficacy of oral antibiotics against intravenous antibiotics in the community setting as there are service implications for cost and comfort.

Penicillins. A current review of their clinical pharmacology and therapeutic use

The penicillins are a large group of bicyclic ring compounds which contain a 4-membered beta-lactam ring (penams) fused to a 5-membered thiazolidine ring. Benzylpenicillin (penicillin G) was the first natural penicillin with potent activity against all Gram-positive pathogens, Gram-negative cocci and some spirochaetes and actinomycetes. For the last 50 years benzylpenicillin has been the mainstay of therapy for serious pneumococcal, streptococcal, meningococcal and gonococcal infections. However, the past decade has seen the emergence of resistance in certain parts of the world, initially among the gonococci, and more recently among the pneumococci and meningococci. Discovery of the 6-aminopenicillinamic acid nucleus has led to considerable manipulation of the basic ring structure, resulting initially in the synthesis of ampicillin, and subsequently the other aminopenicillins, analogues, esters and prodrugs. These drugs have the advantages of improved oral bioavailability and superior activity against Haemophilus influenzae, certain Gram-negative bacilli, salmonellae, enterococci and Listeria monocytogenes, making these agents popular in the treatment of upper and lower respiratory tract infections and urinary tract infections. The increasing spread of bacterial resistance, particularly among Enterobacteriaceae and H. influenzae, has curtailed the usefulness of these drugs in these clinical settings. To counteract this problem, a number of agents combining a penicillin and a beta-lactamase inhibitor (e.g. clavulanic acid, tazobactam and sulbactam) have been developed. These inhibitors have no intrinsic antibacterial activity, but combining them with a penicillin (e.g. amoxicillin/clavulanic acid) confers greater stability to beta-lactamases and hence a broader spectrum of activity. The emergence of penicillinase-producing staphylococci that rendered benzylpenicillin ineffective also stimulated the search for penicillinase-resistant penicillins--methicillin and nafcillin, followed by the acid-stable isoxazolyl penicillins. These agents are now the principle antistaphylococcal treatment. Methicillin-resistant coagulase-negative staphylococci are currently a major cause of hospital sepsis, and are resistant to these latter agents. Enteric Gram-negative bacilli have been the predominant cause of serious hospital infections during the last 30 years. Further manipulation of the penicillin structure has resulted in compounds with broader activity against Gram-negative bacilli, particularly Pseudomonas aeruginosa, while retaining activity against Gram-positive pathogens. The carboxypenicillins were the first step in this direction, but have been largely superseded by the ureidopenicillins. These agents have better activity against P. aeruginosa, and are still effective against Gram-negative and Gram-positive bacteria, including enterococci and anaerobic organisms.(ABSTRACT TRUNCATED AT 400 WORDS)

Efficacy and safety of aztreonam-clindamycin versus tobramycin-clindamycin in the treatment of lower respiratory tract infections caused by aerobic gram-negative bacilli

A total of 80 patients were randomized to receive either aztreonam or tobramycin for the treatment of lower respiratory tract infections caused by gram-negative bacilli; all these patients received clindamycin concomitantly. A total of 53 patients were randomized to receive aztreonam-clindamycin; of these, 46 were clinically evaluable and 39 were bacteriologically evaluable. Of the 46 clinically evaluable patients, 41 were considered cured, 3 failed to be cured, and 2 died during the study period of unrelated causes. Of the 39 bacteriologically evaluable patients, 36 were considered cured, and 3 failed to be cured. There were 26 clinically evaluable patients in the group randomized to receive tobramycin-clindamycin. Of them, 22 patients were considered cured, 3 failed to be cured, and 1 died of unrelated causes during the study period. There were 18 bacteriologically evaluable patients in the tobramycin-clindamycin group; 17 were cured, and 1 failed to be cured. The most common pathogens isolated from the patients were Klebsiella pneumoniae, Escherichia coli, and Pseudomonas aeruginosa. All of the isolated organisms were susceptible to both tested antibiotics, except for a strain of Pseudomonas cepacia resistant to both tested antimicrobial agents and a strain of Enterobacter aerogenes and one of P. aeruginosa that were resistant to aztreonam. Very few adverse reactions related to the antibiotics were seen. These effects, when present, were transient and comparable in both studied groups, except for renal-function tests, which were altered in 7.7% of the patients randomized to receive tobramycin-clindamycin and in none of the patients randomized to receive aztreonam-clindamycin. Aztreonam-clindamycin is safe and effective for the treatment of lower respiratory tract infections caused by aerobic gram-negative bacilli when the organisms are susceptible.

Microbiology, pharmacology, and clinical use of mezlocillin sodium

The acylureido penicillin mezlocillin is active against gram-positive, gram-negative, and anaerobic bacteria. It easily penetrates the outer membrane of gram-negative bacteria, and it has a strong affinity for penicillin binding protein 3. Its stability to beta-lactamases is weak. Mezlocillin is synergistic when given in combination with aminoglycoside antibiotics. In pharmacokinetic studies mezlocillin conforms to a two compartment open model; its pharmacokinetic properties are dose-dependent. The half-life of the drug is about 1 hour after intravenous injection and 1.5 hours after intramuscular injection. Protein binding ranges from 16 to 42%, and 55% of a dose is excreted in the urine. Biliary excretion ranges from 0.5 to 25%. Clinical trial cure rates were as follows: bacteremia (78%), respiratory tract (62%), urinary tract (81%), gynecological (86%), bone and joint (55%), intraabdominal (67%) and skin and soft tissue (59%). The frequency of adverse reactions was 7.7%. Interstitial nephritis, CNS toxicity, and bleeding have not been reported.