Clinical efficacy of cefotaxime in serious infections

Cefotaxime in the treatment of staphylococcal infections. Comparison of in vitro and in vivo studies

Staphylococcus aureus strains are well-established pathogens that may cause mild to serious life-threatening disease. Coagulase-negative staphylococci, particularly Staphylococcus epidermidis, also have a pathogenic role in humans and cause infections primarily associated with prosthetic devices and indwelling catheters, whereas Staphylococcus saprophyticus usually causes urinary tract infections. Cefotaxime is a "third-generation" cephalosporin that is stable to the staphylococcal beta-lactamases. In vitro studies over the last 15 years have shown that this parenteral cephalosporin has remained highly active (MIC90 ranges of < or = 2-8 micrograms/ml) against oxacillin-susceptible staphylococci. Cefotaxime therapy of staphylococcal infections has resulted in clinical cure/improvement rates ranging from 78%-100% and bacteriologic eradication rates ranging from 85%-100% in a wide variety of infections. Contrary to contemporary dogma, this "third-generation" cephalosporin appears to be efficacious against staphylococcal infections from a review of 15 years of clinical experience.

Comparative study of three different dosing regimens of cefotaxime for treatment of gram-negative bacteremia

Thirty-one patients with Gram-negative bacteremia with organisms susceptible to cefotaxime (CTX) (MIC of 1 microgram/ml or less) were randomized to receive 2 g of CTX every 6, 8, or 12 hr. Five-hour susceptibility studies were performed on a bacterial pellet obtained from the patient's positive blood culture vial. Thus, patients were enrolled within hours after Gram-negative organisms were demonstrated in their blood cultures. All bacteremias were cleared although two patients had unsatisfactory responses to therapy. Trough serum bactericidal levels were 1:2 or greater in all patients. This study supports that CTX can be used at an 8- or 12-hr intervals in selected patients with Gram-negative bacteremia.

Development of resistance during antibiotic therapy

The frequency of development of resistance during antibiotic therapy was evaluated by reviewing the literature according to prescribed criteria. Mean resistance rates were calculated to be 9.2% for broad spectrum penicillins, 8.6% for second and third generation cephalosporins, 10.0% for latamoxef, 4.7% for imipenem, 11.8% for ciprofloxacin and 13.4% for aminoglycosides. Emergence of resistance of the infecting organism was associated with therapeutic failure in about half of the cases with the exception of patients treated with aminoglycosides in whom development of resistance resulted in treatment failure in 85% of the cases. The possible benefit of combination therapy in terms of resistance development is discussed.

Outbreak of cephalosporin resistant Enterobacter cloacae infection in a neonatal intensive care unit

Enterobacter cloacae resistant to third generation cephalosporins emerged rapidly during an outbreak of serious infections due to this organism in a neonatal intensive care unit where ampicillin and gentamicin were used as first line antibiotic treatment. Organisms resistant to cephalosporins were isolated from 12 infants, six of whom developed systemic infection. Two infants died. Isolates of E. cloacae from four of five infants treated with cefotaxime showed a loss of sensitivity to this antibiotic during treatment, but in the three infants who survived sensitive organisms were again isolated after treatment had stopped. Stopping treatment with the cephalosporins, closure of the unit to new admissions, and strict cohorting of colonised infants resulted in a prompt end to the outbreak. This outbreak suggests that the routine use of third generation cephalosporins for suspected sepsis may be inappropriate in the presence of a large reservoir of organisms with the potential for rapidly developing resistance. Routine bacteriological surveillance, however, might permit their use on a rotational basis.

Cephalosporins in gram-positive infections

Infections caused by Gram-positive bacteria are an important and common cause of morbidity and mortality. Staphylococci and streptococci are the most frequent infecting organisms in skin and soft tissue infections, pneumonia, bone and joint infections, and endocarditis. Anaerobic Gram-positive bacteria such as Clostridia spp. cause infections that can rapidly produce tissue necrosis and death. The cephalosporins are indicated for the treatment of infections caused by Gram-positive bacteria in certain circumstances. These include selected patients with endocarditis, osteomyelitis, septic arthritis and cellulitis. They are also used as alternatives to the penicillins in penicillin-allergic patients and for 'mixed' infections caused by Gram-positive and Gram-negative organisms. This article discusses the indications for the cephalosporin group of antibiotics in patients suffering from infections caused by Gram-positive bacteria.

Use of ceftazidime in the treatment of nosocomial lower respiratory infections

Patients with hospital-acquired lower respiratory infections pose both diagnostic and therapeutic challenges. Such infections are commonly seen in critically ill patients. When nosocomial pneumonia is suspected, treatment is generally initiated with broad-spectrum antibiotics before culture results become available. The usual therapeutic regimen includes an aminoglycoside with or without a beta-lactam agent. In a clinical efficacy study of a single agent, ceftazidime, in the treatment of 20 adults with hospital-acquired lower respiratory infection, 18 patients showed clinical improvement with ceftazidime therapy and pathogens were eradicated in 11. Therapeutic failures occurred in two patients who received empiric therapy prior to the isolation of pathogens resistant to ceftazidime. The median minimal inhibitory concentration of ceftazidime for the isolated pathogens was 0.78 micrograms/ml. Of the 15 patients infected with Pseudomonas aeruginosa, 14 showed a favorable clinical response. Therapy-limiting side effects occurred in two patients and bacillary resistance developed in one patient. The efficacy and safety of ceftazidime in the treatment of hospital-acquired pneumonias were comparable to results previously demonstrated for amikacin, cefotaxime, and imipenem in studies conducted at our institution. In studies reported in the literature, 44 of 51 patients (86 percent) with nosocomial pneumonia who were treated with ceftazidime had a favorable clinical response to therapy. The patients included in these studies were neither neutropenic nor commonly bacteremic, and none had cystic fibrosis. Ceftazidime appears to be a useful agent in the treatment of selected patients with nosocomial pneumonias, including those due to P. aeruginosa.

Cefotaxime: efficacy and tolerance in lower respiratory tract infections caused by gram-positive cocci

Cefotaxime is an effective antibiotic in lower respiratory tract infection caused by streptococci and staphylococci. There is a limited tendency to superinfections with Pseudomonas aeruginosa (1.5%) and there is a low incidence of side-effects. It is questionable whether there is really an urgent need for cefotaxime in gram-positive lower respiratory tract infections.

Gram-positive superinfections following beta-lactam chemotherapy: the significance of the enterococcus

The recent literature was reviewed with regard to the risks of superinfection following beta-lactam chemotherapy. The summary publications for the pseudomonas-active penicillins (azlocillin, carbenicillin, mezlocillin, piperacillin and ticarcillin), cefoperazone, cefotaxime, ceftazidime, imipenem and moxalactam show marked variations. Moxalactam was most likely to produce both gram-negative (5-38%) and enterococcal (2.2-12%) superinfections. Ceftazidime or moxalactam therapy was more often associated with anaerobic superinfections, usually by Clostridium spp., than the other beta-lactams. Comparable and lower incidences of superinfections were cited for cefoperazone, ceftazidime, mezlocillin and imipenem. The most common pathogens for the above drugs were the fungi (Candida spp.), Pseudomonas spp. and some beta-lactamase-producing Enterobacteriaceae. Staphylococcal, Escherichia coli and Klebsiella spp. secondary infections were more common in patients receiving the newer penicillins. Cefotaxime had a very low incidence of superinfections (1.1%), especially caused by gram-positive organisms such as enterococci. The reasons for this favorable feature seem to be: excellent inhibitory activity and beta-lactamase stability against a wide variety of bacterial pathogens, synergistic interactions of cefotaxime and its desacetyl metabolite, enhanced anti-enterococcal activity of cefotaxime in the presence of a human serum factor and interactions of cefotaxime and desacetyl cefotaxime to suppress the development of antimicrobial resistance. The most common superinfections following cefotaxime treatment were with Pseudomonas spp., Enterobacter spp. and fungi. Cefotaxime appears to possess physical-chemical characteristics that react favorably with bacteria and the host to minimize gram-positive superinfections, especially with most enteric Streptococcus spp. (Streptococcus faecalis and Streptococcus faecium).

Clinical experience of cefotaxime in infections caused by gram-positive pathogens

We studied the activity of cefotaxime both microbiologically and clinically. 138 blood cultures positive for gram-positive cocci were evaluated (90 strains of Staphylococcus aureus, 25 of Streptococcus faecalis, 13 of Streptococcus alpha and ten of Streptococcus mutans). Cefotaxime showed good activity against all strains with the exception of S. mutans, of which only 30% were sensitive. Ten cases of gram-positive infections were studied clinically: six sepsis cases and one endocarditis case due to S. aureus, two sepsis cases caused by Streptococcus alpha and one Enterococcus endocarditis case. Therapy was successful in nine; the S. aureus endocarditis failed. The local and general tolerance of cefotaxime was good.

A review of the use of cefotaxime in the treatment of skin and skin structure infections, with special reference to gram-positive pathogens

Data compiled from computer-generated summaries of patient records submitted to Hoechst-Roussel Pharmaceuticals were reviewed regarding the efficacy and toxicity of cefotaxime in the therapy of skin and skin structure infections associated with gram-positive pathogens. In addition, published open and comparative trials employing cefotaxime in gram-positive and gram-negative skin infections were evaluated with respect to the pathogens isolated and the nature, severity and bacteriological and clinical outcome of the treated infections. Within the limitations of the data reviewed, cefotaxime appeared to be a safe and effective therapy in greater than 90% of infections including cellulitis, abscesses and necrotizing ulcers of the skin and subcutaneous tissues when associated with the isolation of susceptible gram-negative bacilli, methicillin-susceptible Staphylococcus aureus, or aerobic or anaerobic gram-positive pathogens susceptible to aqueous penicillin G. The data would indicate that cefotaxime is a suitable therapy for patients with presumed polymicrobial, non-crepitant infections of the skin or skin structures pending microbiological studies. However, cefotaxime cannot be recommended for similar infections due to organisms such as methicillin-resistant S. aureus or Pseudomonas aeruginosa that are commonly resistant to cefotaxime in vitro. Data regarding skin and skin structure infections associated with Clostridium spp. and enterococcal group D streptococci are either lacking or inconclusive with respect to the utility of cefotaxime.

Respiratory superinfections after the use of third-generation cephem antibiotics

This paper is a report on our studies on superinfections in respiratory tract infections treated during the years 1981-1984. The isolated strains of Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus faecalis, Streptococcus faecium and glucose non-fermentative gram-negative rods such as Pseudomonas aeruginosa were resistant to third-generation cephem antibiotics. These organisms proved to be widely distributed in hospitals and were frequently isolated from the sputum, excised lung and cardiac blood. The colonization of the sputum by bacteria in respiratory tract infections before, during and after treatment with third-generation cephem antibiotics revealed a tendency for these organisms to appear after treatment. Among the gram-positive cocci, S. faecium was most resistant to these antibiotics, followed by S. faecalis, S. epidermidis and S. aureus in that order. The incidence of resistant isolates in 1984 exceeded that in 1983, suggesting an annual increase in resistant bacteria.

In vitro susceptibilities of 393 recent clinical isolates to WIN 49375, cefotaxime, tobramycin, and piperacillin

The in vitro susceptibilities of 393 recent clinical isolates to WIN 49375, a new quinolone derivative, were determined and concurrently tested with cefotaxime, tobramycin, and piperacillin. In general, members of the family Enterobacteriaceae were not as susceptible to tobramycin and piperacillin as they were to WIN 49375. Methicillin-resistant and -susceptible Staphylococcus aureus were equally susceptible to WIN 49375.

A cephalosporin active in vivo against Nocardia: efficacy of cefotaxime in murine model of acute pulmonary nocardiosis

Cefotaxime, a cephalosporin drug, has been shown to be active in vitro against nocardiae, a finding confirmed in this study. Pharmacokinetic studies were performed in mice to define regimens which provided peak serum levels comparable to that achieved in man with currently used doses. These regimens were shown to be effective with only short courses of therapy of rapidly progressive and highly lethal N. asteroides infection, produced by pulmonary challenge of mice. This suggests the possible utility of this drug in human nocardiosis.

Serum bactericidal activity of ceftazidime and cefoperazone alone or in combination with amikacin against Pseudomonas aeruginosa and Klebsiella pneumoniae

Sera of volunteers receiving ceftazidime (2 g) or amikacin (500 mg), alone or in combination, or cefoperazone (2, 4, or 6 g) or cefoperazone (2 g) with amikacin (500 mg) were evaluated for bactericidal activity against Klebsiella pneumoniae and Pseudomonas aeruginosa. Serum bactericidal activities were similar for ceftazidime and ceftazidime plus amikacin, but were definitely lower for amikacin alone. Against P. aeruginosa, a 6-g dose of cefoperazone resulted in a higher frequency of peak serum bactericidal activities greater than or equal to 1:8 than a 2-g dose of cefoperazone plus amikacin. Killing studies, performed in 1:8 diluted serum, demonstrated a higher killing rate for cefoperazone plus amikacin than for a 6-g dose of cefoperazone, the more resistant P. aeruginosa excepted. Emergence of resistance was found with a 2-g dose of cefoperazone for K. pneumoniae and with a 6-g dose of cefoperazone for P. aeruginosa, but not with cefoperazone plus amikacin.

Cefotaxime. A review of its antibacterial activity, pharmacological properties and therapeutic use

SYNOPSIS

Cefotaxime is a new 'third generation' semisynthetic cephalosporin administered intravenously or intramuscularly. It has a broad spectrum of activity against Gram-positive and Gram-negative aerobic and anaerobic bacteria, and is generally more active against Gram-negative bacteria than the 'first' and 'second generation' cephalosporins. Although cefotaxime has some activity against Pseudomonas aeruginosa, on the basis of present evidence it cannot be recommended as sole antibiotic therapy for pseudomonal infections. However, cefotaxime has been effective in treating infections due to other 'difficult' organisms, such as multidrug-resistant Enterobacteriaceae. Like other cephalosporins, cefotaxime is effective in treating patients with complicated urinary tract and lower respiratory tract infections, particularly pneumonia caused by Gram-negative bacilli. High response rates have also been achieved in patients with Gram-negative bacteraemia. Although favourable clinical results have been obtained in patients with infections caused by mixed aerobic/anaerobic organisms (such as peritonitis or soft tissue infections), the relatively low in vitro activity of cefotaxime against Bacteroides fragilis may restrict its usage in situations where this organism is the suspected or proven pathogen. In preliminary studies, males and females treated with a single intramuscular dose of cefotaxime for uncomplicated gonorrhoea caused by penicillinase-producing strains of Neisseria gonorrhoeae responded very favourably. Encouraging results have also been reported in open studies in children including neonates, treated with cefotaxime for meningitis and various other serious infections. In some situations, cefotaxime has been given in combination with another antibiotic such as an aminoglycoside, but the merits of such a combination have not been clearly established. Whether cefotaxime alone is appropriate therapy for conditions previously treated with aminoglycosides (other than pseudomonal infections) also needs additional clarification, but if established as equally effective in such conditions cefotaxime offers potentially important clinical and practical advantages in its apparent lack of serious adverse effects and freedom from the need to undertake drug plasma concentration monitoring.

Emergence of resistance to beta-lactam and aminoglycoside antibiotics during moxalactam therapy of Pseudomonas aeruginosa infections

In four patients with Pseudomonas aeruginosa infections, the infecting strain developed resistance to moxalactam during therapy with this drug. In addition, P. aeruginosa isolates from two of these four patients showed increased resistance to aminoglycosides. Isolates from a third patient acquired cross-resistance to other antipseudomonal beta-lactams. In three of the cases, disk susceptibility tests failed to detect the resistance that was demonstrated in broth dilution assays. Isolate identities were confirmed by serotyping. No new plasmids were found by agarose gel electrophoresis. The mechanisms for this resistance did not involve enzymatic antibiotic degradation. These findings suggest that currently available expanded-spectrum cephalosporin derivatives should probably not be used alone for most serious infections due to P. aeruginosa. They also suggest that strains with multiple antibiotic resistance may become more prevalent in hospitals if these drugs are used extensively.