In vitro activity of BRL 36650, a new semisynthetic penicillin

Pseudomonas aeruginosa infection in cancer patients

Pseudomonas aeruginosa is an important cause of infection in immunosuppressed patients, particularly those with cancer. However, it is being recognized with greater frequency in patients who appear to be immunocompetent. Changes in modern lifestyles have led to the appearance of some new manifestations of pseudomonas infection including corneal ulceration and keratitis associated with contact lenses, and hot-tub- or whirlpool-associated folliculitis. These represent additional hazards to patients with cancer. Many studies, both in animals and humans, have contributed to our knowledge of the pathogenesis, immunology, treatment, and prevention of pseudomonas infections. Although the aminoglycosides represented a significant step forward in the treatment of these infections, of greater importance was the discovery of the antipseudomonal penicillins. These antibiotics are more effective than the aminoglycosides in neutropenic patients, who are especially susceptible to pseudomonal infections. The older antipseudomonal penicillins (carbenicillin, tircarcillin) have largely been replaced by newer ones (mezlocillin, azlocillin, pipercillin) which are more potent in vitro against P. aeruginosa. Although the accepted therapeutic practice has been to utilize a penicillin in combination with an aminoglycoside, the introduction of newer beta lactam agents and fluoroquinolones with antipseudomonal properties offers the possibility of other approaches to combination therapy. These include the combination of a penicillin or a cephalosporin or the combination of a quinolone with an aminoglycoside or a betalactam antibiotic. However, the development of newer antimicrobial agents is not likely to be a lasting solution to the problem of pseudomonas infections. Since pseudomonas infection often progresses rapidly, optimal results will always depend upon the prompt initiation of appropriate therapy in febrile patients, particularly those who are at high risk. The use of granulocyte transfusions has proved to be of limited benefit. Early data with the use of monoclonal antibodies is promising, and the results of large-scale trials are eagerly awaited. It is hoped that continuing investigation of pseudomonas vaccines will lead to the discovery of effective prophylaxis for highly susceptible patients. It is also hoped that with the availability of GM-CSF it will become possible to reduce the period of risk for serious infections. Finally, a reduction in the frequency of microbiologically proven P. aeruginosa infections in cancer patients should not lead to the assumption that these organisms do not constitute a problem in such patients anymore. The use of prophylactic antibiotics and prompt empiric antibiotic coverage for therapy has resulted in this decline. Cultures are therefore unlikely to be positive with the same frequency as they were before antimicrobial prophylaxis and empiric antibiotic therapy became standard practice.(ABSTRACT TRUNCATED AT 400 WORDS)

Antibiotics in acute pancreatitis. Current status and future directions

Infectious complications currently account for 80 percent of deaths from acute pancreatitis. The adjunctive role of antibiotics in the prevention and treatment of secondary pancreatic infections has received insufficient attention. Randomized clinical studies of effective antibiotics for prophylaxis or empiric therapy of pancreatic infections do not currently exist. In their absence, it is not known whether prophylactic antibiotics are useful in patients with acute pancreatitis. Until such studies are available, if antibiotics are to be used, their choice must be based upon indirect criteria: the ability of the antibiotic to effectively penetrate pancreatic tissue and juice, knowledge of the most common pancreatic pathogens, and the ability of the antibiotic to exceed the in vitro concentration (MIC-90) in pancreatic juice for the common pathogens. Recognition of the limited state of knowledge regarding antibiotics in acute pancreatitis may stimulate future investigations.

In vitro susceptibility of Citrobacter species to various antimicrobial agents

The in vitro activities of 16 antimicrobial agents against 14 clinical isolates of Citrobacter diversus and 27 isolates of Citrobacter freundii were studied. C. freundii isolates were more resistant, being susceptible only to amikacin, netilmicin, gentamicin, imipenem, ciprofloxacin, and enoxacin. C. diversus isolates were susceptible to many more of the agents tested.

In vitro evaluation of S-25930 and S-25932, two new quinolones, against aerobic gram-negative isolates from cancer patients

The in vitro activity of S-25930 and S-25932, two new 4-quinolones, against 450 aerobic gram-negative organisms isolated from cancer patients was evaluated and compared with the activity of ciprofloxacin, enoxacin, difloxacin (A-56619), and A-56620. Both agents inhibited most members of the family Enterobacteriaceae at concentrations of less than or equal to 2.0 micrograms/ml, but their activity against Pseudomonas aeruginosa was inferior to that of other quinolones. Although considerably less active than ciprofloxacin and A-56620, S-25930 was frequently two- to eightfold more active than S-25932 and was comparable to difloxacin and enoxacin against most isolates.

In vitro susceptibility of Acinetobacter species to various antimicrobial agents

The in vitro activity of 18 antimicrobial agents against 40 clinical isolates each of Acinetobacter calcoaceticus subsp. anitratum and Acinetobacter lwoffi was studied. Most of the newer 4-quinolone derivatives were extremely active against these organisms. Newer beta-lactam agents, such as cefpirome, BMY 28142, and BRL 36650, were also extremely active, inhibiting all strains at clinically achievable levels. Most agents were two- to fourfold more active against A. lwoffi.