Approach to the management of fever and granulocytopenia

In recent years, advances in chemotherapy for malignant disease have resulted in a greater population of patients with granulocytopenia whose course in often complicated by fever. We reviewed the current medical literature in an attempt to identify the most appropriate management of this special patient population. Our findings suggest that patients with fever and granulocytopenia and without a diagnosis of infectious disease who improve on empiric antimicrobial therapy should continue to receive empiric therapy until their granulocytes recover. Patients in this same category who remain febrile probably do not have an infectious cause of their fever, and discontinuation of empiric antibiotics should be considered if they appear clinically stable. A guideline to the management of these patients is presented.

Penicillin-aminoglycoside inactivation: another possible mechanism of interaction

A case of a carbenicillin-tobramycin interaction resulting in laboratory test reports of subtherapeutic serum tobramycin levels in a 71-year-old man with renal failure is reported. The patient's Pseudomonas aeruginosa infection was treated with carbenicillin, 2 g every eight hours, and tobramycin, 80 mg after daily hemodialysis. The serum antibiotic levels were monitored using a microbiologic assay and a radioimmunoassay technique. At 30 minutes and five hours after the tobramycin was administered, microbiologic assay of serum levels indicated negligible tobramycin concentrations (2 micrograms/ml). Radioimmunoassay of tobramycin levels showed markedly higher concentrations (4.1 micrograms/ml at 30 minutes after infusion). The difference in assay results was attributed to greater inactivation occurring with the microbiologic assay, which was the less rapid technique. In vitro and in vivo factors influencing the occurrence and extent of the carbenicillin-tobramycin interaction are reviewed. When using an aminoglycoside-penicillin combination in patients with renal failure, it is important to use a rapid assay technique or one that inactivates one of the antibiotics before bioassay, and to be aware of the patient-related factors that can alter assay results.

Allergological examination of cystic fibrosis patients with skin reactions during carbenicillin treatment

Sixteen of 84 cystic fibrosis patients developed skin manifestations during intensive carbenicillin therapy. The possibility of allergic drug reactions was examined. None of the patients showed any significant levels of antibodies of IgE, IgG or IgM classes against carbenicillin and different penicilloyl determinants as recorded with RAST, sandwich-radioimmunoassay and double antibody assay. The leukocytes of the patients did not release histamine on in vitro provocation with carbenicillin. Furthermore, none of the patients responded to prick test or to peroral penicillin provocation. The negative findings indicated that the recorded reactions were most probably not due to antibody-mediated allergy of type I or type III.

Experimental osteomyelitis caused by Pseudomonas aeruginosa

An experimental model of chronic osteomyelitis caused by Pseudomonas aeruginosa was established with use of techniques identical to those employed previously with Staphylococcus. Infection of bone was consistently produced, but the disease was less severe than that seen with Staphylococcus. There were lower mortality, decreased severity of infection as demonstrated by X ray, and less evidence of sequestrum formation with P. aeruginosa than with Staphylococcus. Carbenicillin was used alone and in combination with sisomicin in the treatment of experimental pseudomonas osteomyelitis. The combination, when administered for four weeks, was significantly more effective than either agent alone.

Levels of carbenicillin in serum and prostatic tissue after intravenous administration in patients with benign prostatic hyperplasia

Carbenicillin (CB-PC) was administered intravenously (5 gm over one-half hour) to 25 patients suffering form benign prostatic hyperplasia. Prostatic biopsies and sera were obtained one, two, three, four, and five hours later for histology and biochemical analyses of the serum and prostatic tissue levels of CB-PC. The serum and prostatic tissue levels of carbenicillin attained were sufficient to eradicate gram-negative bacteria within the five time intervals studied. The ratio of prostatic tissue level of CB-PC to the serum level of this agent increased in proportion to the grading of round cell infiltration of the prostatic tissue. The results of this study point to the clinical usefulness of CB-PC in the treatment of chronic and acute prostatitis.

Multiple of isolates of Pseudomonas aeruginosa with differing antimicrobial susceptibility patterns from patients with cystic fibrosis

Clinical isolates of Pseudomonas aeruginosa from patients with cystic fibrosis were studied in an effort to determine the unique characteristics of the infecting strains and to elucidate the pattern of colonization. Of 413 patients studied, 81% were chronically infected with P. aeruginosa. Patients from whom P. aeruginosa was never or only occasionally isolated were in better clinical condition than the chronically infected patients. Isolates were classified into six morphologic varieties: classic, rough, mucoid, gelatinous, dwarf, and enterobacter. Most patients had two or more of these varieties. Such multiple varieties from the same individual were of the same serotype but often differed in antibiotic susceptibility as determined by both the disk and the minimal inhibitory concentration methods. These differences were apparent when mucoid strains were compared with nonmucoid strains and when nonmucoid strains were compared with one another. Studies of antibiotic susceptibility should be performed on each morphologically different type of P. aeruginosa obtained from patients with cystic fibrosis.

Comparison of antibiotic regimens for treatment of experimental pneumonia due to Pseudomonas

The high mortality associated with pneumonia due to Pseudomonas aeruginosa prompted a comparative trial of several currently available antibiotic regimens for this infection in a guinea pig model. Normal guinea pigs receiving an intratracheal challenge of 10(8) colony-forming units of Pseudomonas routinely died within 3-48 hr when treated with saline injections. Treatment with carbenicillin or ticarcillin did not affect this uniformly fatal outcome. Groups of animals treated with gentamicin or tobramycin had survival rates of 39% and 67%, respectively. The addition of either carbenicillin or ticarcillin to an aminoglycoside failed to enhance further the survival rates or durations of survival after infection. These survival data were supported by studies showing superior clearance of viable Pseudomonas from lung tissues in aminoglycoside-treated animals chosen at random for sacrifice 3 hr after infection. Thus, in animals experimentally challenged with P. aeruginosa to cause pneumonia and in which only a single isolate of Pseudomonas was evaluated, protection from pulmonary infection was best provided by an aminoglycoside rather than by a beta-lactam antibiotic.

Treatment of Pseudomonas endophthalmitis associated with prosthetic intraocular lens implantation

Eight patients were treated for Pseudomonas endophthalmitis associated with the implantation of contaminated intraocular lenses. All patients showed clinical signs of infection (loss of red reflex, diminished visual acuity, and intraocular lens coagulum) and P. aeruginosa was isolated from vitreous aspirates and unused lenses of the same lot. Antibiotic treatment was initiated with systemic penicillin G, cephalothin, and chloramphenicol as well as subtenon-injected gentamicin. After identification of the organism, treatment was continued with systemic carbenicillin and gentamicin and subtenon-injected gentamicin. The intraocular lens was left in place for the first 48 hours of treatment in all eight patients. Five patients were successfully treated without removal of the intraocular lens and attained visual acuity of 6/6 (20/20) to 6/15 (20/50). Three patients (the two most seriously infected and one in whom antibiotics were discontinued) eventually lost their infected eye. Vitreous concentrations of gentamicin were good in one patient (1.7 micrograms/ml) and undetectable in another. Carbenicillin concentrations in vitreous (96 and 140 micrograms/ml) were high in two patients sampled. Endophthalmitis in the presence of a prosthetic intraocular lens can be successfully treated in some patients without removal of the prosthesis.

A randomized study of carbenicillin plus cefamandole or tobramycin in the treatment of febrile episodes in cancer patients

Patients were randomly assigned to receive carbenicillin plus tobramycin by continuous infusion (C+T), carbenicillin plus cefamandole by continuous infusion (C+CC) or carbenicillin plus cefamandole by intermittent infusion (C+IC) during 490 febrile episodes. Carbenicillin was administered over 2 hours every 4 hours. The per cent of cures achieved during the 235 documented infections was 65 per cent for C+CC, 57 per cent for C+IC and 54 per cent for C+T. Among those infections caused by single gram-negative bacilli, C+CC produced a higher cure rate than C+IC or C+T(74 per cent versus 59 per cent versus 50 per cent). C+CC was significantly more effective than C+IC among patients with persistent severe neutropenia of less than 100 neutrophils/mm3 (65 per cent versus 21 per cent, p = 0.03). If the infecting organism was sensitive to both antibiotics, the cure rate which occurred during 12 per cent to 13 per cent of the febrile episodes, regardless of antibiotic regimen. However, it occurred significantly more often during documented infections than during fevers of unknown etiology (20 per cent versus 6 per cent, p less than 0.001). C+CC appears to be the most effective of the three regimens for the treatment of infections in patients with persistent severe neutropenia.

Chemotherapy of chronic infections with mucoid Pseudomonas aeruginosa in lower airways of patients with cystic fibrosis

The bacteriological effect of chemotherapy against Pseudomonas aeruginosa (Ps.ae.) in lungs of patients with cystic fibrosis is reviewed. During a 5-year period 49 children and adults were treated with 190 courses of different antibiotics. The mucoid strains of Ps.ae. disappeared in 72.0% of the courses in which a combination of tobramycin and carbenicillin was employed. Tobramycin given alone had only bacteriological effect in 26.6% of the courses. Colimycin alone or in combination with carbenicillin had no effect. In 18 patients who received subsequent courses of tobramycin and combination of tobramycin and carbenicillin a significant difference in favour of the combination therapy was found, also in cases with many precipitins against Ps.ae. in serum. In 74.5% of the initially successful courses the patients were recolonized with Ps.ae. within 1 month. No nephrotoxic or ototoxic side effects were demonstrated in spite of the high doses of tobramycin (10 mg/kg/24 h) emmployed and the repeated courses.

Anaerobic isolates in chronic recurrent suppurative otitis media. Treatment with carbenicillin alone and in combination with gentamicin

Tympanocentesis was performed in 32 pediatric patients with chronic recurrent suppurative otitis media. The aspirate was cultured aerobically and anaerobically. Aerobes were isolated from ten patients (31.2%); anaerobes from one patient; and both aerobes and anaerobes from 21 patients (65.6%). There were 46 aerobic isolates. The aerobes commonly recovered were Pseudomonas aeruginosa (24 isolates) Proteus sp. (5) and Staphylococcus aureus (3). There were 32 anaerobes isolated including anaerobic gram-positive cocci (19 isolates) and Bacteroides sp., the latter of which included Bacteroides fragilis group and Bacteroides melaninogenicus (9). The patients were treated by parenteral carbenicillin 300 to 400 mg per kg per day given in four dosages administered for a period of 12 to 21 days (average 17 days). An aminoglycoside (gentamicin) was added in 15 patients. The clinical response was good in 17 patients and poor in 15. There were no side effects or adverse reactions noted during therapy. The above findings demonstrate the polymicrobial etiology of chronic recurrent suppurative otitis media and suggest that treatment directed against the aerobic and anaerobic isolates is efficacious in more than half of the cases.

Bacteriology and treatment of chronic otitis media

Tympanocentesis was performed in 50 patients with chronic otitis media. Pus was cultured aerobically and anaerobically. Aerobes only were isolated from 21 patients, 3 had only anaerobes (peptococcus sp.) and 26 had both aerobes and anaerobes. There were 68 aerobic isolates. Pseudomonas aeruginosa was recovered in 36 (72%). Other aerobes commonly recovered included proteus sp. and Staphylococcus aureus. There were 48 anaerobes isolated. Anaerobic gram positive cocci were isolated in 24 instances. Sixteen Bacteriodes sp. were recovered, including 7 B. fragilis and 6 B. melaninogenicus. The patients were divided into two groups according to their antimicrobial therapy: 28 received carbenicillin and 22 clindamycin. An aminoglycoside was added when aerobic enteric gram negative rods were present in significantly high numbers in the culture. There was good to excellent response to therapy in more than half of the patients and in 12% there was a remission from symptoms for up to one year. Thirty-six percent of the patients had no response to therapy. There were no statistical differences in response to therapy in the two groups treated. Antimicrobial therapy directed against aerobic and anaerobic isolates from chronic otitis media had a high success rate in complete eradication of the infection.

[Clinical effectiveness of carbenicillin in suppurative inflammatory processes of varying localization]

The study on sensitivity of clinical strains of the causative agents of purulent infections to carbenicillin showed that 34.6% of the staphylococcal strains, 48.1% of the E. coli strains and 40.3% of the Proteus strains were sensitive to the antibiotic. The strains of Ps. aeruginosa were characterized by moderate sensitivity to carbenicillin. The MTC for most of the isolates ranged within 25-128 microgram/ml. High therapeutic efficacy of carbenicillin in treatment of cases with purulent inflammatory processes of various localization was shown. Positive results were obtained in 82.5% of the adults and 76.2% of the premature infants treated with carbenicillin. A satisfactory therapeutic effect was observed in the cases with sepsis, diffuse purulent peritonitis and abscessing pneumonia treated with carbenicillin in combination with gentamicin.

Relative efficacy of carbenicillin indanyl sodium and of trimethoprim/sulfamethoxazole in urinary-tract infections

In a 10-day study, carbenicillin indanyl sodium cured urinary-tract infections in 22 of 30 patients (ages, 24-91). In 3 of the remaining patients the treatment was a failure; in 3 others the drug had to be discontinued because of diarrhea and vomiting; and in 2 instances it induced overgrowth of Candida albicans in the urine. Carbenicillin was lethal to Pseudomonas aeruginosa in all 9 cases, to Proteus mirabilis in all 6 cases, and to enterococcus in all 3 cases. A trimethoprim/sulfamethoxazole combination cured urinary-tract infections in 18 of 30 other patients (ages, 28-91), but failed in 3. In 3 patients it gave rise to a skin rash; in 2 to elevation of blood urea nitrogen and creatinine levels; in 1 to neutropenia; and in 1 to overgrowth of Candida albicans in the urine. Reinfection occurred in 2 patients. Carbenicillin indanyl sodium was more effective than the sulfonamide/trimethoprim combination.