Empiric Therapy of Infections in Hematologic Malignancies: A Prospective, Randomized Trial

Patients with hematologic malignancies were randomly assigned to receive cefuroxime (group A) or tobramycin plus ampicillin (Group B) during 86 febrile episodes. In both regimens carbenicillin was added during neutropenia (71% of all episodes: groups C and D). The most common type of infection was pneumonia (48% alone; 72% with other sites involved), which accounted for a high fatality rate (15%); the highest rate occurred during septicemia with pneumonia (50%). The overall response rate to initial therapy was 63% without significant differences among the four regimens. The worst prognosis was observed in neutropenic patients without granulocyte recovery. When initial and cross-over trials were combined, there were favorable outcomes in 90% of all cases. Cefuroxime alone seems to be as effective as tobramycin plus ampicillin in the treatment of infections in hematologic malignancies. No side effects could be attributed to the cefuroxime-containing regimens.

[Gastrointestinal carriage of Pseudomonas aeruginosa in children residing in chronic care institutes in Jerusalem: high prevalence and high rates of antibiotic resistance]

BACKGROUND

Pseudomonas aeruginosa carriage in the gastrointestinal tract is uncommon in healthy children. Children living in chronic care institutions are often carriers of P. aeruginosa in the respiratory tract, but data is lacking regarding gastrointestinal carriage in these children.

AIMS

To examine the carriage rate of P. aeruginosa in children living in chronic care institutions in Jerusalem and to assess resistance rates of the bacteria to different classes of antibiotics.

METHODS

Rectal swabs were taken from all children residing in two chronic care institutions in Jerusalem: "St. Vincent" and "Aleh". The swabs were examined for presence of Pseudomonas aeruginosa. The authors used disk diffusion technique and E Test to assess resistance for different antibiotics.

RESULTS

Gastrointestinal carriage of P. aeruginosa was detected in 37 out of 125 of the children (30%); 16% of the P. aeruginosa isolates were resistant to carbapenems; 16% were resistant to aminoglycosides, 14% to ureidopenicillins and 11% to quinolones. All isolates were sensitive to ceftazidime and colistin. In 84% of the isolates, the minimal inhibitory concentration (MIC) for meropenem was significantly lower than the MIC for imipenem.

SUMMARY

P. aeruginosa is a common colonizer of the gastrointestinal tract of children living in chronic care institutions. Empiric antibiotic treatment against P. aeruginosa should be considered when treating children with acute gastrointestinal pathologies. Antibiotic resistance, and particularly carbapenem resistance, is common in this population. There is a significant difference between the MICs for imipenem and meropenem. Future studies are needed to understand the clinical significance of this finding.

A case of meningoencephalitis associated with G1P[8] rotavirus infection in a Japanese child

We report the case of a 2-y, 11-month-old boy with G1P[8] rotavirus infection accompanied by acute meningoencephalitis. Substitutions in both the VP4 and VP7 genes were found in the identified strain. A commonly circulating G1P[8] rotavirus with such mutations might be associated with the pathogenesis of CNS complications, including meningoencephalitis.

Latamoxef versus carbenicillin plus gentamicin or carbenicillin plus mecillinam in leukopenic, febrile patients with solid tumors

Sixty-six febrile episodes associated with leukopenia were observed in 56 patients with solid tumors, WBC less than 1.5 X 10(9)/l and temperature greater than or equal to 38.5 degrees C. Stratification to antibiotic treatment regimen was made with regard to prior cis-dichlorodiamineplatinum (cis-platinum) treatment or not. Patients who had received no cis-platinum were randomized between carbenicillin 10 g every 8 h plus gentamicin 80 mg every 8 h or latamoxef 2 g every 8 h (group I). Patients having received cis-platinum were treated with carbenicillin 10 g every 8 h plus mecillinam 800 mg every 8 h or latamoxef 2 g every 8 h (group II). The first dose of latamoxef was preceded by 10 mg of vitamin K i.v. In group I, clinical response was observed in 10 of 19 febrile episodes (52.6%) treated with carbenicillin plus gentamicin and in 10 of 14 (71.4%) treated with latamoxef (p greater than 0.05). In group II, 6 of 14 febrile episodes treated with carbenicillin plus mecillinam responded (42.9%) while 11 of 19 (57.9%) responded to latamoxef (p greater than 0.05). No bleeding due to antibiotic treatment was observed. No statistical difference between standard antibiotic therapy and latamoxef was seen in this subset of patients.

[Anti-Pseudomonas aerosol therapy in cystic fibrosis: improvement with tobramycin]

Aerosol delivery of antibiotics offers the potential to achieve high antibiotic concentrations at the site of infection while reducing the risk of systemic untoward effects because of minimal resorption into the bloodstream. We reviewed knowledge acquired in this field over the two latter decades. While the earliest data were obtained with gentamycin, the most conclusive evidence presently regards aminoglycosides and colistin. Aerosol delivery of tobramycin was recently improved with the development of a new formulation for inhalation. Coupled with an adequate nebulization system, intermittent treatment with tobramycin for inhalation has been evaluated in randomized placebo-controlled studies. These studies have demonstrated a significant improvement of respiratory function.

Pseudomonas aeruginosa ventilator-associated pneumonia: comparison of episodes due to piperacillin-resistant versus piperacillin-susceptible organisms

We sought to determine the epidemiological characteristics of patients in an intensive care unit (ICU) who developed ventilator-associated pneumonia (VAP) caused by piperacillin-resistant Pseudomonas aeruginosa (PRPA; n=34) or piperacillin-susceptible P. aeruginosa (PSPA; n=101). According to univariate analysis, the factors associated with the development of PRPA VAP were presence of an underlying fatal medical condition, immunocompromised status, longer previous hospital stay, less-severe illness at the time of ICU admission, duration of mechanical ventilation before onset of VAP, number of classes of antibiotic received, and previous exposure to imipenem or fluoroquinolone. Multivariate logistic regression analysis identified the following significant independent factors: presence of an underlying fatal medical condition (odds ratio [OR], 5.6), previous fluoroquinolone use (OR, 4.6), and initial disease severity (OR, 0.8). We concluded that the clinical characteristics of patients who develop PRPA VAP differ from those of patients who develop PSPA VAP. Restricted fluoroquinolone use is the sole independent risk factor for PRPA VAP that is open to medical intervention.

Empirical antimicrobial therapy in pediatric patients with neutropenia and fever. Risk factors for treatment failure

BACKGROUND

The use of combinations of antibiotics has been the cornerstone of therapy for febrile patients with cancer and severe neutropenia. Each empirical regimen should be selected according to the epidemiology and susceptibility patterns in each center. We describe here the experience with empirical antimicrobial treatments in pediatric patients with cancer, fever and severe neutropenia, and identify the risk factors associated with treatment failure.

METHODS

This is a prospective study including 145 patients with cancer, and 171 episodes of neutropenia and fever. Blood cultures were taken before initiating empirical treatment: a) carbenicillin (400 mg/kg/day) plus amikacin (21 mg/kg/day) (Cb/ak), and b) ceftazidime (100 mg/kg/day), plus amikacin at the same dosage (Cz/ak).

RESULTS

The overall response rate was 54.9% and 56.3% for Cb/ak and Cz/ak, respectively. Fifty-seven episodes (33.3%) were microbiologically documented, gram-positive isolated in 38% and gram-negative in 49%. Risk factors associated significantly with treatment failure were acute myelocytic leukemia (AML) (RR 2.59, CI 95% 1.42-4.7, p = 0.003); bacteriological identification (RR = 4.41, CI 95% 2.21-8.8, p < 0.001), and the presence of two or more sites of infection (RR = 2.89, CI 95% 1.03-8.11, p = 0.03).

CONCLUSIONS

The rates of response are similar to the combinations used in the hospital (Cb/ak, Cz/ak). The risk factors associated with treatment failure were AML diagnosis, bacteriological identification, and the presence of two or more sites of infection.

Antibiotic resistance in bacterial urinary tract infections, 1991 to 1997

This study assessed changing patterns of antibiotic resistance in Escherichia coli urinary tract infections at a university student health center during three periods: the first 6 months each of 1991, 1994, and 1997. Urine culture and sensitivity results were taken from available medical records of female patients having urine cultures during the three periods (1991, n = 739; 1994, n = 938; 1997, n = 863); age and ethnicity were also noted. In E. coli isolates (the majority of positive cultures), resistance to four antibiotics changed significantly: ampicillin (30% to 45% to 39%), carbenicillin (29% to 42% to 39%), tetracycline (29% to 40% to 23%), and trimethoprim/sulfamethoxazole (15% to 32% to 15%). The results raise questions regarding the future clinical reliability of several commonly used antibiotics in the treatment of urinary tract infection.

Randomized trial comparing oral ciprofloxacin plus penicillin V with amikacin plus carbenicillin or ceftazidime for empirical treatment of febrile neutropenic cancer patients

Aminoglycoside-containing combination therapy has been the standard empirical approach for febrile neutropenic cancer patients. With the advent of the broad-spectrum oral fluoroquinolones, it is now possible to evaluate an initial empirical alternative therapy. A prospective randomized study was conducted comparing oral ciprofloxacin plus penicillin V (group A) with amikacin plus carbenicillin or ceftazidime (group B). Main criteria for eligibility were febrile patients with solid tumor or nonlymphoblastic lymphoma, a Zubrod PS equal to 1 or 2, no diarrhea, mucositis, or long-term central venous catheter. A total of 108 consecutive neutropenic febrile episodes were randomized (5 exclusions); 55 episodes were assigned to group A and 48 to group B. Most febrile episodes were of unknown origin. There were 10 microbiologically documented episodes with two cases of bacteremia. Both regimens were well tolerated. Oral regimen was substantially cheaper than parenteral regimen. Treatment success without regimen modification was 94.5% for group A and 93.8% for group B (p = .86; CI -0.08-0.10). Oral therapy with ciprofloxacin and penicillin V is a safe alternative to standard parenteral therapy in this low-risk group of neutropenic patients, with unquestionable cost containment.

The treatment of acute myeloid leukemia in Brazil: progress and obstacles

BACKGROUND

Substantial progress has been made in the treatment of acute myeloid leukemia in the last two decades. We wanted to evaluate the outcome of intensive chemotherapy and the influence of recent therapy changes in underprivileged patients treated in a large urban public university hospital.

METHODS

The records of all patients treated for acute myeloid leukemia from 1980 to 1993 were analyzed.

RESULTS

109 patients were identified; 41 did not receive any treatment for the leukemia because of infectious and/or hemorrhagic complications of advanced disease. Median survival in this group was 4 days. The other 68 patients received one of two induction protocols: TAD from 1980 to 1985 (n = 23) and ara-C plus daunorubicin from 1985 to 1992 (n = 45). The complete remission rate was 56%, disease-free survival 24% and overall survival 15% at 13 years. Overall survival was better for patients treated with ara-C plus daunorubicin than with TAD (19% versus 8%, p = 0.01). This is attributed to a reduction in infection mortality after ceftazidime and amikacin replaced cephalotin, carbenicillin and amikacin as the antibiotic regimen.

CONCLUSIONS

The most effective intervention in our population would probably be an improvement in the primary health care system, so that earlier diagnosis could allow the treatment of a larger fraction of patients.

Management of an infected urachal cyst during pregnancy

An infected urachal cyst complicating a pregnancy is extremely rare, but is considered to present a high risk to both the mother and the fetus. We treated a patient with an infected urachal cyst diagnosed at 29 weeks of gestation. A healthy infant was delivered by cesarean section at 37 weeks of gestation. The patient underwent excision of the unruptured cyst 37 days later. This is the first reported case of an infected urachal cyst complicating a pregnancy, that was diagnosed before rupture and was managed without serious sequelae for either the mother or the fetus. The diagnosis and management of the infected urachal cyst complicating the pregnancy is discussed.

Aeromonas species in septicemia: laboratory characteristics and clinical observations

We retrospectively analyzed clinical and epidemiological data on and laboratory characteristics of 53 cases of aeromonas septicemia. Only four Aeromonas genomospecies (species defined by DNA relatedness) were associated with the 53 cases, with Aeromonas hydrophila (sensu stricto) predominating (47%). Nearly 60% of all Aeromonas isolates from blood fell into one of four somatic groups: serogroups O:11, O:16, O:18, and O:34. Unlike Aeromonas-associated gastroenteritis, septicemia did not peak in frequency during the warmer months but rather was most common in January through March, when approximately 40% of cases occurred. In vitro tests of the pathogenicity of 20 selected blood isolates of Aeromonas indicated that resistance to complement-mediated lysis, elevated levels of protease and hemolysin activity, and the ability to elaborate siderophores correlated with higher virulence. Species and serogroup designations also correlated with the degree of virulence. Susceptibility studies of 50 strains indicated that A. hydrophila was the most drug-resistant species and that Aeromonas veronii was the most susceptible. Susceptibility to first- and second-generation cephalosporins and carbenicillin was species-associated.

[Sensitivity of pathogens of post-ventilation pneumonia in newborns to antibacterial drugs]

The majority of the enteric bacteria and aerobic and anaerobic cocci causing postventilation pneumonia in newborns were susceptible to gentamicin, carbenicillin, ampicillin and cephalosporins. The strains of Pseudomonas aeruginosa were mainly susceptible to gentamicin and carbenicillin. Bacteroides were susceptible to metronidazole, ceftazidime and lincomycin. 70.8 per cent of the causative agents of the pneumonia were polyresistant to at least 6 antibiotics.

[The characteristics of lysozyme and carbenicillin action on the clinico-immunological status of patients with chronic bronchitis]

Clinical, laboratory and immunological methods used to study 68 patients with chronic bronchitis revealed a normalizing effect of intratracheal administration of lyzozyme and its combinations with carbenicillin on the indices of cellular and humoral links of immunity. Treatment tactics is discussed.

Randomised comparison of oral ofloxacin alone with combination of parenteral antibiotics in neutropenic febrile patients

Prompt treatment with empirical antibiotics in neutropenic febrile patients reduces morbidity and mortality. Most patients have been treated with parenteral combination antibiotics, but newer antibiotics with broad-spectrum bactericidal activity have made monotherapy feasible. Ofloxacin, a broad-spectrum fluoroquinolone, has the additional advantage that bactericidal concentrations can be achieved with oral administration. We have compared ofloxacin as an oral single agent with standard parenteral combination antibiotics for the management of neutropenic febrile patients in a prospective, randomised trial. Patients with severe neutropenia (absolute neutrophil count less than or equal to 0.5 x 10(9)/l), fever above 38 degrees C, and ability to take drugs by mouth were eligible for the study. After initial investigations, 60 patients were randomly assigned to oral ofloxacin 400 mg twice daily and 62 to parenteral combination antibiotic therapy (amikacin 15 mg/kg daily, plus, at various times in the trial, carbenicillin, cloxacillin, or piperacillin). Patients were examined 72 h and 7 days after the start of treatment and when neutropenia resolved. 24 (40%) ofloxacin-treated and 26 (42%) combination-treated patients had pyrexia of unknown origin (PUO). In both treatment groups, the treatment success rate was higher for such patients than for those with clinically or microbiologically documented infections (92% vs 67% [p less than 0.05] for ofloxacin; 85% vs 64% for combination). There were no significant differences in success rates of ofloxacin and combination treatment for these subgroups or overall (77% vs 73%). Patients with neutropenia for less than 1 week had better responses to both treatments than patients with longer-lasting neutropenia. There were 4 (7%) deaths in the ofloxacin group and 6 (10%) in the combination group. Both regimens were well tolerated. We conclude that oral single-agent ofloxacin is as effective as parenteral combination antibiotic therapy in neutropenic febrile patients, especially those expected to have short durations of neutropenia.

Adverse reactions to prolonged treatment with high doses of carbenicillin and ureidopenicillins

Charts were reviewed for 63 patients whose chronic pseudomonas osteomyelitis was treated with high doses of extended-spectrum penicillins for prolonged periods. The incidence of untoward drug reactions was significantly higher than expected. Carbenicillin evoked adverse reactions in 22.8% of patients. However, most of these reactions were mild, and a change of drug was required in only 5.7% of cases. No adverse drug reactions were observed with cumulative doses of less than 750 g. In contrast to carbenicillin, the ureidopenicillins were associated with adverse reactions in 67.7% of patients; most reactions were moderate to severe in intensity; a cumulative dose of greater than 250 g produced adverse reactions; and discontinuation or change of therapy was required in 51.6% of cases. The main adverse reactions to both carbenicillin and the ureidopenicillins included rash, drug fever, leukopenia, eosinophilia, thrombocytopenia, and hepatic damage.

The efficacy of norfloxacin in the treatment of chronic bacterial prostatitis refractory to trimethoprim-sulfamethoxazole and/or carbenicillin

We treated 15 men who had chronic bacterial prostatitis refractory to trimethoprim-sulfamethoxazole and/or carbenicillin with 400 mg. norfloxacin twice daily for 28 days. All pathogens were susceptible to norfloxacin and absent in prostatic fluid cultures obtained during therapy. One patient had negative post-therapy prostatic fluid cultures but was lost to followup at 1 month. Of the 14 patients followed for at least 6 months 9 (64%) were cured of the original infection, including 6 who have remained uninfected and have had negative prostatic secretion and urine cultures for at least 2 years (1), 1 year (2) or 6 months (3). In 3 patients urinary tract infections recurred with new pathogens at 6, 560 and 820 days after post-therapy negative prostatic fluid cultures. Bacterial prostatitis with the original pathogen recurred in 5 patients within 2 months of completing therapy. The bacteria remained susceptible to norfloxacin but could not be eradicated with 30 to 90 days of additional norfloxacin therapy. Cures were achieved in 9 of 12 patients with Escherichia coli, none of 2 with Pseudomonas prostatitis and 3 of 5 with prostatic calculi. No patient experienced significant adverse effects. The data suggest that norfloxacin is effective and safe for the treatment of refractory chronic bacterial prostatitis.

Ofloxacin in the management of complicated urinary tract infections, including prostatitis

Studies of ofloxacin pharmacokinetics and pathogen susceptibilities suggested that this new fluoroquinolone might be particularly well suited to the treatment of urinary tract infections and prostatitis. Compared with carbenicillin and trimethoprim/sulfamethoxazole in separate studies of complicated urinary tract infection, ofloxacin achieved a significantly higher rate (p = 0.048) of microbiologic cures and more clinical cures than carbenicillin, while essentially matching the efficacy of the trimethoprim/sulfamethoxazole combination. Most common organisms were Pseudomonas aeruginosa in the first study and Escherichia coli in the second. In preliminary data from the prostatitis study comparing ofloxacin 300 mg given twice daily with carbenicillin 764 mg given every six hours, microbiologic cure rates were 100 percent with both medications. However, clinical cure rates were significantly higher (p = 0.048) with ofloxacin. Throughout these trials, ofloxacin has shown excellent safety and tolerability, with a lower incidence of nausea and diarrhea than with carbenicillin, and less nausea and rash than with trimethoprim/sulfamethoxazole. In all treatment groups, clinically significant laboratory abnormalities were uncommon and unrelated to the medications. Overall, these studies indicate that in complicated urinary tract infection the efficacy of ofloxacin is comparable with that of trimethoprim/sulfamethoxazole and superior to that of carbenicillin. In chronic bacterial prostatitis, results to date suggest that ofloxacin may be more effective clinically and as effective microbiologically as carbenicillin.

Achromobacter xylosoxidans corneal ulcer in a therapeutic soft contact lens wearer

Achromobacter xylosoxidans is an opportunistic organism that is usually seen in immunocompromised or immunosuppressed patients. It is an aerobic gram-negative rod, often confused with other more commonly seen gram-negative bacteria such as Pseudomonas aeruginosa. The organism is usually sensitive to extended spectrum penicillins such as carbenicillin and usually resistant to aminoglycosides and first generation cephalosporins. We wish to describe a corneal ulcer from A. xylosoxidans that developed in a patient wearing a therapeutic soft contact lens. The patient did not have a preexisting microbial keratitis and was not receiving corticosteroid therapy.

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.