Delayed cerebrospinal fluid sterilization in infants with Hemophilus influenzae type b meningitis

Cerebrospinal fluid (CSF) sterilization after greater than 24 h of intravenous antibiotic therapy (delayed CSF sterilization) was noted in two infants treated with ceftizoxime and ceftazidime for bacterial meningitis. A case-control study was conducted of children between 6 w and 6 y of age treated between 1975 and 1985 at one institution for bacterial meningitis to determine risk factors for delayed CSF sterilization. Hemophilus influenzae type b was isolated from all children (n = 5) with delayed CSF sterilization, compared with only 78% of all children in the study (n = 83). In children with H. influenzae type b disease, children less than 6 mo of age were at higher risk than older children for delayed CSF sterilization (odds ratio = 7.5, 95% confidence limits = 1.4, 40.0). Factors not associated with delayed CSF sterilization included time of follow-up lumbar puncture, CSF total or differential white blood cell count, and CSF protein and glucose concentrations. Despite the in vitro antimicrobial susceptibility of H. influenzae type b to ceftizoxime and ceftazidime, delayed CSF sterilization may occur in infants receiving these antibiotics for bacterial meningitis.

Deposition of carbenicillin aerosols in cystic fibrosis: effects of nebuliser system and breathing pattern

Antibiotic aerosol treatment is successful in treating Pseudomonas infection in some patients with cystic fibrosis, but the amount of drug reaching the lungs is unknown. The deposition patterns of carbenicillin aerosols delivered from two commercially available nebuliser systems (the Turret nebuliser plus Maxi compressor and the Inspiron nebuliser plus Traveller compressor) have been compared in six patients with cystic fibrosis during tidal breathing. The aerosol mass median diameters were 3.2 and 7.3 microns. In addition, the aerosol from the Turret-Maxi nebuliser system was inhaled by a combination of tidal and deep breathing. After two minutes' breathing via a mouthpiece the mean (SEM) deposition in the lungs was 15.60 (1.5) mg carbenicillin with the Turret nebuliser plus Maxi compressor, but only 6.54 (1.09) mg with the Inspiron nebuliser plus Traveller compressor; the distribution pattern within the lung was significantly more peripheral with the former nebuliser system. These differences may be ascribed partly to the smaller droplet size from the Turret system and partly to the higher nebulisation rate from the more powerful Maxi compressor. Tidal plus deep breathing produced a further small but non-significant increase in lung aerosol deposition. A seventh patient, who failed to complete the trial, had little aerosol deposited in his lungs because he inhaled through his nose. These results emphasise the importance of correct selection of nebuliser equipment for antibiotic aerosol treatment.

Ceftazidime with or without vancomycin vs. cephalothin, carbenicillin and gentamicin as the initial therapy of the febrile neutropenic pediatric cancer patient

In a 28-month randomized trial we compared ceftazidime (CAZ), an extended spectrum cephalosporin, with cephalothin, carbenicillin and gentamicin (KCG) as empiric therapy for febrile neutropenic pediatric cancer patients. Because of the occurrence of ceftazidime-resistant Gram-positive primary infections, vancomycin was added to CAZ after the first year of study. Of 206 evaluable episodes 76 (37%) were documented infections including 20 bacteremias; 130 (63%) episodes were caused by fever of unknown origin. The number of complete responses to initial therapy in patients with documented infections did not differ among regimens: 26 of 43 (61%) for KCG, 9 of 16 (56%) for ceftazidime and 8 of 16 (50%) for CAZ + vancomycin (not significant). In patients with fever of unknown origin, response without modification of the initial regimen was 52 of 62 (84%) in the KCG arm, 32 of 40 (80%) on CAZ and 23 of 29 (80%) in patients treated with CAZ + vancomycin (not significant). Modifications of the regimen were similar among all three groups and were due primarily to the use of empiric antifungal or antiviral therapy and to empiric treatment of interstitial pneumonia. Hypokalemia occurred in 25 of 105 patients treated with KCG and in 4 of 101 treated with CAZ or CAZ + vancomycin (P less than 0.001). No differences between the efficacy of KCG, CAZ and CAZ + vancomycin as initial empiric therapy were demonstrated.

Inhaled ceftazidime compared with gentamicin and carbenicillin in older patients with cystic fibrosis infected with Pseudomonas aeruginosa

A randomized cross-over study was undertaken to compare nebulized (1) ceftazidime with (2) a combination of gentamicin and carbenicillin, and (3) saline, each given for 4 months, in patients with cystic fibrosis infected with Pseudomonas aeruginosa. Mean peak expiratory flow on ceftazidime, 299 litres/min, and on gentamicin and carbenicillin, 297 litres/min, were greater than on saline, 278 litres/min (P less than 0.02 and P less than 0.05 respectively). Similarly mean forced expiratory volume in 1 second on ceftazidime, 1.70 litres, and on gentamicin and carbenicillin, 1.70 litres, were greater than on saline, 1.48 litres (P less than 0.02 and P less than 0.01 respectively). Mean forced vital capacity on gentamicin and carbenicillin, 2.93 litres, was also greater than on saline (P less than 0.05). We were unable to demonstrate any difference in efficacy between the antibiotic regimens. The patients were admitted to hospital less frequently during the study year compared with the previous year (P less than 0.05). Sixty-nine per cent of patients had a clinically significant (20%) increase in forced expiratory volume in 1 second on an antibiotic regimen compared with that on entry to study, but a minority of patients appear not to respond to this form of treatment.

In vitro models for the study of combination antibiotic therapy in neutropenic patients

Neutropenic patients are at risk of serious infection caused by gram-negative bacilli and staphylococci. The mortality rate associated with gram-negative bacteremia in these patients is extremely high, especially in those with persistent and profound granulocytopenia. In these latter patients, the best results have been obtained by administering combinations of antibiotics in which both agents are active and/or show in vitro synergism against the infecting organism. Most combinations include an aminoglycoside such as amikacin and a broad-spectrum beta-lactam antibiotic, such as azlocillin, mezlocillin, piperacillin, or ceftazidime. The International Antimicrobial Therapy Project Group of the European Organization for Research and Treatment of Cancer has completed several studies evaluating various antibiotic combinations in the empiric treatment of febrile neutropenic patients. These trials have evaluated cephalothin plus gentamicin, carbenicillin plus gentamicin, and cephalothin plus carbenicillin; carbenicillin plus amikacin and carbenicillin plus amikacin plus cefazolin; azlocillin plus amikacin, ticarcillin plus amikacin, and cefotaxime plus amikacin; and azlocillin plus amikacin versus ceftazidime plus long- or short-course amikacin. The preclinical evaluation of antibiotic combinations usually involves the in vitro testing of antibiotics alone and in combination by the checkerboard method or with the use of time-kill curves. However, these methods expose the bacterial culture to a static or constant concentration of the drugs. During the in vivo treatment of infections, bacteria are exposed to changing concentrations of antibiotics, which are contingent on the individual pharmacokinetics of these drugs. We have designed a two-compartment in vitro pharmacokinetic model that allows the simultaneous study of the activity of two antibiotics with similar or different half-lives against a number of bacteria. Amikacin and azlocillin have been studied alone and in combination in this model against Pseudomonas aeruginosa, a frequent cause of bacteremia in neutropenic patients. In pharmacologically relevant doses, amikacin alone produced rapid bacterial killing, followed by regrowth of resistant subpopulations. Azlocillin alone produced a more gradual reduction of the bacterial inoculum, with ultimate bacteriostasis. Amikacin plus azlocillin produced rapid and complete eradication of the organism. In vitro pharmacokinetic models may prove to be more predictive of clinical outcome than are traditional static in vitro methods used to study antibiotic combinations.

Use of carbenicillin in two species of tortoise (Testudo graeca and T hermanni)

A preliminary investigation of the blood levels of carbenicillin, after the administration of a single intramuscular injection, suggests that the tortoise's bladder may act as a reservoir of antibiotic that is available for resorption. This phenomenon could confound the establishment of a safe, effective dose regime for antibiotics, in tortoises, which are excreted in an unchanged active form in urine.

Prophylactic antibiotics in transurethral resection of bladder tumors: are they necessary?

In a double-blind study, 30 patients having transurethral surgery for bladder tumors were randomly assigned to receive prophylactic carbenicillin indanyl sodium or a placebo perioperatively. Only one patient in the carbenicillin group had a postoperative urinary infection due to carbenicillin-resistant Klebsiella oxytoca organisms. Thus, no advantage from the prophylactic use of antibiotics was evident in this uninfected group of patients.

Evaluation of high-dose tobramycin-carbenicillin therapy in pseudomonal infections in cystic fibrosis

Fourteen episodes of acute pseudomonal pulmonary exacerbations of cystic fibrosis were treated with high-dose tobramycin (10.1-17.1 mg/kg/d) and carbenicillin (600 mg/kg/d). The Sawchuck-Zaske method of dosing tobramycin was used and resulted in good agreement between the desired and measured peak (8.1 +/- 0.5 vs. 8.2 +/- 1.5 micrograms/ml) and trough (0.5 +/- 0.2 vs. 1.0 +/- 0.4 micrograms/ml) concentrations. Ninety-three percent of cases improved clinically. Forced expiratory volume in one second and forced vital capacity increased significantly (39.3 +/- 24.8, p less than 0.001 and 24.1 +/- 22.8 percent, p less than 0.05, respectively) after treatment. Pseudomonas aeruginosa was eradicated from the sputa of 69 percent of the cases, with recolonization occurring within three months. Significant nephrotoxicity and ototoxicity were not seen. Liver enzymes, however, were elevated in 29 percent of those treated. Combination high-dose carbenicillin and tobramycin satisfies the treatment goals of bacteriological and clinical cure with a minimal degree of toxicity.

Comparison of cefamandole and carbenicillin in preventing sepsis following penetrating abdominal trauma

One hundred and five patients with penetrating abdominal injuries were treated with single-antibiotic regimens. Forty-seven patients were treated with intravenous (IV) cefamandole and for comparison 58 patients were treated with IV carbenicillin previously shown to be effective against postoperative infections associated with abdominal trauma. The overall incidence of deep infection on a single antibiotic therapy was 8.6 per cent, including two patients on cefamandole alone (4.3%) and seven (12.1%) on carbenicillin alone. One in each antibiotic group died of sepsis with a total mortality of 1.9 per cent. The authors concluded that cefamandole when used alone was found to be safe and more effective than carbenicillin alone in preventing sepsis in patients with abdominal trauma.

[Laboratory methods of controlling the effectiveness of antibacterial therapy]

The serum antibacterial activity (SAA) against causative agent isolated after the use of antibiotics was studied in 68 patients with pyoseptic diseases. The SAA ranged from 1:2 to 1:512 and depended on the antibiotic sensitivity of the causative agents. Antibiotic therapy was effective, when the SAA was equal to 1:8-1:512. With the use of monotherapy the adequacy of the regimens was controlled by the relation between the maximal blood level of the antibiotic and its MIC for the causative agent. The favourable clinical effect of the treatment with aminoglycosides and beta-lactams corresponded to the SAA exceeding 4.

Ceftazidime compared with gentamicin and carbenicillin in patients with cystic fibrosis, pulmonary pseudomonas infection, and an exacerbation of respiratory symptoms. British Thoracic Society Research Committee

An open randomised comparison of a new intravenous cephalosporin, ceftazidime, with the established regimen of gentamicin and carbenicillin was carried out in patients with cystic fibrosis who had persisting pulmonary infection with Pseudomonas species and who developed acute exacerbations of respiratory symptoms. Fifty patients received ceftazidime and 32 gentamicin and carbenicillin. The ceftazidime and gentamicin were given every eight hours and the carbenicillin every six hours. The mean total daily doses were 151 mg/kg for ceftazidime, 6.3 mg/kg for gentamicin and 450 mg/kg for carbenicillin. The mean duration of treatment was 10 days in patients receiving gentamicin and carbenicillin and 12 days in those receiving ceftazidime. Of the patients with pseudomonas in the initial sputum specimen in whom sputum was cultured after treatment, six (26%) of 23 receiving gentamicin and carbenicillin and seven (18%) of 39 receiving ceftazidime had sputum free from pseudomonas at the end of treatment, but recolonisation occurred subsequently. In those receiving ceftazidime all 10 coexisting organisms were eliminated, whereas only four of seven coexisting organisms in patients receiving gentamicin and carbenicillin were eliminated. Overall clinical improvement occurred in 25 (78%) of 32 patients treated with gentamicin and carbenicillin and 48 (96%) of 50 patients treated with ceftazidime. Nineteen (59%) of the patients receiving gentamicin and carbenicillin but only 15 (30%) of those receiving ceftazidime required admission to hospital or intravenous antibiotics, or both, or died during the three months after treatment. Side effects in both groups were similar, mild, and infrequent. Thrombophlebitis occurred in four patients treated with gentamicin and carbenicillin but in no patients treated with ceftazidime.

Adverse reactions to piperacillin in adults with cystic fibrosis

Nine adult patients with cystic fibrosis, nearly a quarter of the 38 patients with this disease who were treated with piperacillin (59 courses in all) during 1981-3 at the Brompton Hospital, developed a swinging pyrexia after a mean of 13.5 days' treatment with this antibiotic. The fever resolved shortly after the piperacillin treatment was stopped, as did the widespread rashes in the two patients who developed them. Three of four patients who had probable reactions to azlocillin may have been sensitised by piperacillin. As piperacillin does not appear to be any more effective than other antipseudomonal penicillins in cystic fibrosis, it is no longer used at the hospital for treating bronchopulmonary exacerbations in such patients.

Chronic prostatitis: comments on infectious etiologies and antimicrobial treatment

Twenty-three males with the clinical diagnosis of chronic prostatitis were evaluated for a bacterial etiology by the Stamey and Meares method. In addition, 16 patients, regardless of culture results, were placed on either cefadroxil or oral carbenicillin antimicrobial therapy. Culture results identified only four (17%) of 23 patients with bacterial prostatitis: coagulase-negative Staphylococcus (2), Enterobacter agglomerans (1), and Haemophilus parainfluenzae, and coagulase-negative Staphylococcus (1). Four of seven patients who received oral carbenicillin and three of nine patients who received cefadroxil reported symptomatic relief. This study did not identify a common etiology for chronic prostatitis or a consistently effective antimicrobial treatment. Rather, we observed that the etiologic agent in most cases of chronic prostatitis (83%) could not be identified by routine bacteriologic culture. Future research efforts in chronic prostatitis must address not only treatment regimens but expand the search for etiologic agents.

New pulmonary infiltrates in granulocytopenic cancer patients being treated with antibiotics

During a 5 1/2-year period, 34 of 829 episodes of granulocytopenia during which broad spectrum antibiotics were being administered for fever and/or infections were complicated by the development of new pulmonary infiltrates. In 12 patients the infiltrates were due to fungal pneumonia, while in 6 patients the infiltrates were due to a variety of other causes. In the remaining 16 cases the etiology of the infiltrates was not determined. Time to development of infiltrate, radiographic appearance of the infiltrate, patient temperature and absolute granulocyte count failed to predict the etiology of the infiltrate. Conversely, development of the infiltrate or its radiographic progression in the absence of bone marrow recovery correlated significantly with the diagnosis of fungal pneumonia. While empiric alterations of antibiotics at the time that the infiltrate appeared were not associated with improved survival, the early use of amphotericin B was associated with a significant decrease in fatal fungal pneumonia. We suggest that the diagnostic and therapeutic approach to the febrile, granulocytopenic patient who develops a new pulmonary infiltrate while receiving broad spectrum antibiotic therapy may be guided by the state of marrow recovery at the time of infiltrate appearance. Patients developing an infiltrate coincident with granulocyte recovery may be managed conservatively while patients whose infiltrate develops or progresses in the absence of granulocyte recovery should be considered to be at high risk for fungal pneumonia and if possible undergo a diagnostic lung biopsy and/or empiric antifungal therapy.

Corneal ulcer due to Achromobacter xylosoxidans

We report a case of corneal ulcer caused by the opportunistic organism Achromobacter xylosoxidans which developed during chronic topical steroid treatment of an eye with neovascular glaucoma. A. xylosoxidans has probably been underreported as a cause of ocular infection because of confusion between this organism and other Gram-negative organisms, particularly pseudomonas. A. xylosoxidans is resistant to aminoglycosides and some cephalosporins but not carbenicillin. This difference in antibiotic sensitivity patterns between A. xylosoxidans and pseudomonas makes an accurate differentiation between the 2 organisms important. This case was successfully treated after substituting topical carbenicillin for topical gentamicin and amikacin.

A preliminary study on the use of carbenicillin in snakes

The results of a 10 year survey on the in vitro antibiotic resistance patterns of Pseudomonas spp. isolated from clinically ill reptiles, showed a high degree of sensitivity to carbenicillin. On the basis of sensitivity testing, carbenicillin was used to treat nine snakes of four different species, with confirmed Pseudomonas infections. Plasma carbenicillin levels were assayed, by a microbiological agar diffusion technique, at intervals of time after a single intramuscular injection at a dose rate of 400 mg/kg. Peak plasma levels of 177 and 270 micrograms/ml were reached 1 h after the initial injection and therapeutic levels persisted for at least 12 h. This initial study indicated that a suggested dose regime in snakes, derived by extrapolation from mammalian dosages, of 100-125 mg/kg daily was insufficient to produce plasma levels of sufficient magnitude and duration to effectively treat Pseudomonas infections in snakes.

Evaluation of antibiotic therapy and surgical techniques in cases of homicidal wounds of the colon

Infectious morbidity associated with colonic trauma was evaluated with respect to the specific site of the colonic injury, the surgical method used, and the antibiotic treatment prescribed. Septic complications were more frequent among patients who had left-sided colon injuries (P = less than 0.01) and among those who received antibiotics known to be ineffective against anaerobic bacteria (P = less than 0.01). A statistical analysis of the different surgical methods used, i.e., primary repair of the colon, primary repair with loop exteriorization, or colostomy, was indeterminable.