Comparative in vitro activities of ABT-773 against 362 clinical isolates of anaerobic bacteria

The activity of ABT-773, a novel ketolide antibiotic, against clinical isolates of anaerobic bacteria was determined and compared to the activities of other antimicrobial agents. MICs at which 90% of isolates were inhibited (MIC(90)s) were </=0.06 microg/ml for Actinomyces spp., Clostridium perfringens, Peptostreptococcus spp., Propionibacterium spp., and Porphyromonas spp. The MIC(50)s and MIC(90)s were </=0.06 and >32 microg/ml, respectively, for Eubacterium spp., Lactobacillus spp., Clostridium difficile, and Clostridium ramosum. The MIC(90) for Bilophila wadsworthia, Bacteroides ureolyticus, and Campylobacter gracilis was 1 microg/ml, and that for Prevotella bivia and other Prevotella spp. was 0.5 microg/ml. The MIC(90) for Fusobacterium nucleatum was 8 microg/ml, and that for Fusobacterium mortiferum and Fusobacterium varium was >32 microg/ml. The MIC(90)s for the Bacteroides fragilis group were as follows: for B. fragilis, 8 microg/ml; for Bacteroides thetaiotaomicron, Bacteroides ovatus, Bacteroides distasonis, and Bacteroides uniformis, >32 microg/ml; and for Bacteroides vulgatus, 4 microg/ml. Telithromycin MICs for the B. fragilis group were usually 1 to 2 dilutions higher than ABT-773 MICs. For all strains, ABT-773 was more active than erythromycin by 4 or more dilutions, and for some strains this drug was more active than clindamycin.

Unusual respiratory bacterial flora in cystic fibrosis: microbiologic and clinical features

Pulmonary infections continue to be a significant source of morbidity and mortality among patients with cystic fibrosis. Although our understanding of the pathogenesis and clinical consequences of pulmonary infections with Pseudomonas aeruginosa has increased greatly in recent years, very little is known about potentially emerging pathogens such as Burkholderia cepacia complex, Stenotrophomonas maltophilia, Alcaligenes xylosoxidans, and methicillin-resistant Staphylococcus aureus. In this review, the authors discuss methods for appropriate identification of these "unusual" organisms and their epidemiologic and clinical features. Multicenter surveillance studies are needed to more clearly establish the pathogenicity of these organisms.

In vitro activities of nontraditional antimicrobials against multiresistant Acinetobacter baumannii strains isolated in an intensive care unit outbreak

Fifteen multiresistant Acinetobacter baumannii isolates from patients in intensive care units and 14 nonoutbreak strains were tested to determine in vitro activities of nontraditional antimicrobials, including cefepime, meropenem, netilmicin, azithromycin, doxycycline, rifampin, sulbactam, and trovafloxacin. The latter five drugs were further tested against four of the strains for bactericidal or bacteriostatic activity by performing kill-curve studies at 0.5, 1, 2, and 4 times their MICs. In addition, novel combinations of drugs with sulbactam were examined for synergistic interactions by using a checkerboard configuration. MICs at which 90% of the isolates tested were inhibited for antimicrobials showing activity against the multiresistant A. baumannii strains were as follows (in parentheses): doxycycline (1 microg/ml), azithromycin (4 microg/ml), netilmicin (1 microg/ml), rifampin (8 microg/ml), polymyxin (0.8 U/ml), meropenem (4 microg/ml), trovafloxacin (4 microg/ml), and sulbactam (8 microg/ml). In the kill-curve studies, azithromycin and rifampin were rapidly bactericidal while sulbactam was more slowly bactericidal. Trovafloxacin and doxycycline were bacteriostatic. None of the antimicrobials tested were bactericidal against all strains tested. The synergy studies demonstrated that the combinations of sulbactam with azithromycin, rifampin, doxycycline, or trovafloxacin were generally additive or indifferent.

Novel bacterium isolated from a lung transplant patient with cystic fibrosis

The major clinical problem for patients with cystic fibrosis (CF) is progressive loss of pulmonary function, usually due to chronic bacterial infections. A patient with CF and a lung transplant was severely infected with a previously unidentified gram-negative bacterium. We isolated this organism (strain DS15158) from the patient and characterized it by phylogenetic analysis of the small-subunit rRNA and biochemically by the BIOLOG GN MicroPlate assay, fatty acid analysis, and various standard laboratory tests. No close match to any other organism could be found. Isolate DS15158 represents a new genus-level divergence within the bacterial subdivision alpha-Proteobacteria on the basis of the 16S rRNA gene analysis.

Coccidioides immitis presenting as a hyphal form in cerebrospinal fluid

This article reports a case of Coccidioides immitis that presented as a hyphal form in a 38-year-old patient. The organism was observed growing exclusively as hyphae in the cerebrospinal fluid by microscopic examination. Coccidioides immitis was the only organism cultured. The identification of C immitis was confirmed by both standard culture methods and DNA probe studies.

Comparative in vitro activities of trovafloxacin (CP-99,219) against 221 aerobic and 217 anaerobic bacteria isolated from patients with intra-abdominal infections

Four hundred thirty-eight bacteria cultured from specimens of patients with serious intra-abdominal infections were tested by agar dilution against trovafloxacin and other quinolones and antimicrobial agents. Trovafloxacin inhibited 435 strains (99.3%) at < or =2 microg/ml. All the quinolones had similar activities against Enterobacteriaceae and Pseudomonas sp., but trovafloxacin showed superior activities against streptococci, enterococci, and anaerobic organisms. Because of its excellent in vitro activities against diverse bacteria, trovafloxacin has potential use as a single agent for polymicrobial infections.

Specific antibodies to Trypanosoma cruzi among blood donors in Los Angeles, California

BACKGROUND

Trypanosoma cruzi, the cause of Chagas' disease, is often transmitted by transfusion in Latin America. Previous studies showed that at least 1 in 1000 eligible blood donors at the Los Angeles County+University of Southern California (LAC+USC) Medical Center Blood Bank had specific antibodies to T. cruzi. In June 1993, serologic screening of prospective allogeneic donors at epidemiologic risk for T. cruzi infection was begun voluntarily.

STUDY DESIGN AND METHODS

The risk of T. cruzi infection in all eligible donors was assessed by questionnaire. At-risk donors were screened serologically for antibodies to T. cruzi with an enzyme immunoassay, and confirmatory testing was done with a radioimmunoprecipitation assay.

RESULTS

During the 29-month study period 1311 (39.5%) of 3320 donors were judged to be at risk for T. cruzi infection. Seven donors (1/475) were reactive by an enzyme immunoassay, and six of these seven (1/ 553) were positive in a radioimmunoprecipitation assay. All radioimmunoprecipitation assay-positive donors had been born in countries in which Chagas' disease is endemic. One person in this group had received a transfusion in his homeland.

CONCLUSION

These results demonstrate that a substantive proportion of eligible blood donors at our institution have antibodies specific for T. cruzi and that a commercially available assay can be used to detect these antibodies. Our data suggest that the risk of transmission of T. cruzi by transfusion could be eliminated by serologic testing limited to persons born in or transfused in countries in which Chagas' disease is endemic.

Meropenem versus tobramycin with clindamycin in the antibiotic management of patients with advanced appendicitis

BACKGROUND

Meropenem (MP), a new carbapenem antibiotic, has excellent antimicrobial activity against the enteric flora commonly encountered in acute appendicitis. Although similar to imipenem, it may have clinical advantages.

STUDY DESIGN

We compared patients with advanced appendicitis (gangrenous or perforated) treated with 1,000 mg MP every eight hours with those given the combination of tobramycin 5 mg/kg/day at eight hour intervals and clindamycin 900 mg every eight hours. Both treatments were given intravenously. Patients were randomized to either group of the double-blind study.

RESULTS

Of 129 evaluable cases, 63 received MP and 66 received both tobramycin and clindamycin (T/C). The two groups were similar in age, sex, and severity of disease. The mean number of days of postoperative fever (MP = 3.1 +/- 1.7 SD compared to T/C = 4.4 +/- 2.2 SD, p < or = 0.01), days of antibiotic therapy (MP = 6.1 +/- 1.6 SD compared to T/C = 7.3 +/- 2.2 SD, p = 0.01), and therefore hospital stay (MP = 8.0 +/- 3.5 SD compared to T/C = 9.4 +/- 2.6 SD, p < 0.01) were significantly better for patients treated with MP. No difference was found between the numbers of failures in each group (MP = 5 compared to T/C = 6).

CONCLUSIONS

This study demonstrates a small but significant reduction (approximately one day) in post-operative fever, duration of antibiotic treatment, and hospital stay for patients treated with MP compared to those treated with T/C.

Pharmacoeconomics of piperacillin/tazobactam and imipenem/cilastatin in the treatment of patients with intra-abdominal infections

Costs involved in using piperacillin 4 g/tazobactam 500 mg, given as intermittent intravenous infusions every 8 hours, were compared with those for imipenem/cilastatin 500 mg, given as intermittent intravenous infusions every 6 hours, for the treatment of patients with gangrenous or perforated appendicitis. A total of 88 patients were included in our cost analyses: 42 patients in the piperacillin/tazobactam group and 46 patients in the imipenem/cilastatin group. Durations (mean +/- SD) of antibiotic therapies were 7.8 +/- 3.3 days and 7.1 +/- 2.6 days for the piperacillin/tazobactam and imipenem/cilastatin groups, respectively. No statistical significance was found for the difference in duration of therapy (P = 0.376). Total drug treatment costs were $538.83 +/- $385.33 for the piperacillin/tazobactam group and $687.66 +/- $345.37 for the imipenem/cilastatin group. This difference in treatment cost was statistically significant (P = 0.0001). The need for laboratory tests and the use of other medications were not different between the two groups. Total hospital-days charges were higher for the piperacillin/tazobactam group ($18,339.76 +/- $6090.38) compared with the imipenem/cilastatin group ($16,150.00 +/- $5088.60) (P = 0.052). These findings suggest that length of hospital stay should be the economic focus of antibiotic therapy.

A randomized study of cefepime versus the combination of gentamicin and mezlocillin as an adjunct to surgical treatment in patients with acute cholecystitis

In patients with acute cholecystitis, antibiotics are used as an adjunct to cholecystectomy to reduce the incidence of postoperative septic complications thought to be related to bactibilia. Combinations of penicillins, or cephalosporins or aminoglycosides, or both, are often used. Cefepime is a fourth-generation cephalosporin with excellent activity against gram-positive and gram-negative bacteria, including Pseudomonas species. It has a prolonged serum half-life, allowing twice-daily dosing, and is not nephrotoxic. This study was undertaken to determine whether or not cefepime was as effective as the combination of gentamicin and mezlocillin in patients with acute cholecystitis. One hundred and forty-nine patients were randomized, two to one, to receive cefepime or gentamicin and mezlocillin. Cefepime was given intravenously at 2 grams every 12 hours; gentamicin, 1.0 to 1.5 milligrams per kilograms every eight hours, and mezlocillin, 3 to 4 grams every four to six hours. All patients underwent cholecystectomy. Bile cultures were obtained, and concentrations of cefepime in blood, bile, peritoneal fluid and gallbladder were determined in a subset of patients. There were 56 evaluable cefepime-treated and 34 evaluable gentamicin and mezlocillin-treated patients. Bactibilia was present in 17 of 56 cefepime-treated patients (30.4 percent) and ten of 34 gentamicin and mezlocillin-treated patients (29.4 percent). Enterococci were recovered in six cefepime-treated patients. Clinical and bacteriologic responses were similar for the cefepime-treated and gentamicin and mezlocillin-treated groups, with one failure in each group, a wound infection in a patient receiving cefepime and a subhepatic abscess in a patients receiving gentamicin and mezlocillin. Other measures of outcome, such as the number of days of fever, days nothing by mouth, days of hospitalization and days of antibiotic therapy were similar in both groups. Cefepime, with every 12 hour dosing, achieved extremely high concentrations in all tissues assayed at the time of the operation, a mean of eight hours after administration. Adverse clinical events were similar in both treatment groups. Cefepime is as effective as gentamicin and mezlocillin in preventing septic complications after cholecystectomy for acute cholecystitis. Cefepime requires fewer doses, does not require drug monitoring, is not associated with nephrotoxicity and may therefore prove to be a cost-effective alternative to combination therapy that uses an aminoglycoside.

A clinical comparison of cefepime and metronidazole versus gentamicin and clindamycin in the antibiotic management of surgically treated advanced appendicitis

Many antibiotics and antibiotic combinations are used for the treatment of peritonitis because of advanced (gangrenous or perforated) appendicitis. An aminoglycoside combined with an antianaerobe antibiotic is one standard treatment, but there is concern about the potential nephrotoxicity of the aminoglycoside and the necessity for monitoring aminoglycoside blood levels. Cefepime, a new broad-spectrum cephalosporin with a prolonged serum half-life, has excellent activity against gram-positive and gram-negative bacteria, including Pseudomonas aeruginosa. Its spectrum of activity is similar to the aminoglycosides, but it has less potential for inducing renal injury. A double-blind, randomized study compared cefepime, 2 grams every 12 hours IVPB plus metronidazole 0.5 grams every eight hours IVPB (C/M) with gentamicin 1.5 milligrams per kilograms of IVPB plus clindamycin 0.9 grams q eight hours IVPB (G/C), administered up to 14 days, in 96 surgically treated patients with gangrenous or perforated appendicitis. Fifty patients had advanced appendicitis (nine gangrenous and 41 perforated) in the C/M group and 46 patients (six gangrenous and 40 perforated) in the G/C group. The mean number of days of postoperative fever (C/M, 4.4 +/- 2.7 versus G/C, 5.0 +/- 2.2), postoperative hospitalization (C/M, 2.0 +/- 1.9 versus G/C, 2.0 +/- 2.1) and antibiotic therapy (C/M, 6.3 +/- 1.9 versus G/C, 6.9 +/- 1.9) was similar in the two treatment groups. There were 11 treatment failures (C/M, three; G/C, eight; p = 0.13), six of which were probably a result of enterococci. No deaths occurred. Our study results show that the efficacy of cefepime plus metronidazole is equivalent to that of clindamycin plus gentamicin.

Pharmacokinetics of meropenem in patients with intra-abdominal infections

Noncompartmental and compartmental analyses of meropenem disposition in patients receiving 1-g intravenous intermittent infusions every 8 h were performed. Twelve patients (one woman and 11 men) participated in the meropenem pharmacokinetic analysis. Operative findings included perforated appendicitis (five patients), gangrenous appendicitis (five patients), peri-appendical abscess (one patient), and gunshot wound to the abdomen (one patient). The most common associated adverse drug reactions to meropenem were diarrhea and increased liver enzymes. The estimated noncompartmental pharmacokinetic parameters, mean +/- standard deviation, are as follows: maximum drug concentration in plasma, 47.58 +/- 17.59 micrograms/ml; half-life, 1.04 +/- 0.19 h; elimination rate constant, 0.68 +/- 0.12 h-1; area under the concentration-time curve from 0 h to infinity, 57.5 +/- 20.12 micrograms x ml/h; total plasma clearance, 315.40 +/- 71.94 ml/min; renal clearance, 136.7 +/- 89.20 ml/min; volume of distribution at steady state, 26.68 +/- 6.88 liters; and mean residence time, 1.47 +/- 0.28 h. The two-compartment model best described meropenem disposition in our patients. Our findings differed from estimates for healthy volunteers possibly because of the physiologic changes as a result of surgery. Our findings suggest that meropenem (1,000 mg) administered intravenously every 8 h provides adequate concentrations for most intra-abdominal infections.

Prospective randomized study of two different doses of clindamycin admixed with gentamicin in the management of perforated appendicitis

Septic complications after surgery for enterogenous peritonitis are minimized by adjuvant antibiotics effective against aerobes and anaerobes. Historically, "gold standard" therapy included an aminoglycoside plus clindamycin, the latter given at 600 mg intravenous piggyback (IVPB), every 6 hours. Clindamycin pharmacokinetics suggests that it can be given q8h and admixed with gentamicin, thereby markedly reducing the cost of administration. Although this is now common practice, there is no prospective study comparing the efficacy of the two dose schedules in peritonitis. This study was designed to test the hypothesis regarding the clinical efficacy of the two regimens. One hundred twenty-six patients with gangrenous (n = 34) or perforated appendicitis (n = 91) were randomized (2:1) to receive gentamicin admixed with clindamycin 900 mg IVPB every 8 hours (Group I n = 80) or gentamicin IVPB q8h plus clindamycin 600 mg IVPB every 6 hours (Group II n = 46). Appendectomy was performed, and aerobic and anaerobic cultures were obtained. Twenty-one patients had simultaneous determinations of clindamycin levels in plasma, peritoneal fluid, and appendix. Outcome analysis revealed no significant differences in postoperative days of fever, days non per os, antibiotic therapy, or hospitalization. There were 6 failures (4 abscesses and 2 wound infections) in Group I and 4 failures (1 abscess and 3 wound infections) in Group II. Both antibiotic regimens provided clinically equivalent results in mixed infections due to aerobic and anaerobic bacteria. The admixed clindamycin, administered every 8 hours, results in at least 20% reduction in costs. This is an important consideration.

Use of a questionnaire to identify potential blood donors at risk for infection with Trypanosoma cruzi

Trypanosoma cruzi is the protozoan parasite that causes American trypanosomiasis (Chagas' disease). Chagas' disease is endemic in Latin America. The infection is usually seen in poor people who live in rural areas in substandard housing, where they are bitten by infected reduviid bugs. Transmission also can occur by blood transfusion. Infected individuals who immigrate to the United States might donate blood if they are asymptomatic and unaware of their infection. This study evaluated the usefulness of a questionnaire for identifying T. cruzi-infected individuals among prospective blood donors who met all American Association of Blood Banks, Food and Drug Administration, and State of California criteria for donor eligibility. Seventy-two of 3492 otherwise eligible donors were disqualified because of their answers on the questionnaire. Forty-five of these 72 agreed to be tested serologically, and 2 were positive for T. cruzi antibodies. One of six autologous blood donors tested also was positive for T. cruzi antibodies. We conclude that the questionnaire selected a subgroup of Latin Americans at high risk for T. cruzi infection. The deferral of these high-risk individuals clearly reduced the risk of transmission of T. cruzi by transfusion, without intolerably decreasing the supply of donated blood.

Tissue concentrations of cefepime in acute cholecystitis patients

Cefepime is a new broad-spectrum cephalosporin with activity against Staphylococcus, Streptococcus, Pseudomonas, and the Enterobacteriaceae. The purpose of this study was to measure cefepime concentrations in plasma, peritoneal fluid, bile fluid and appendix tissue in patients undergoing elective cholecystectomy. Patients were randomly assigned to receive either cefepime, 2 g intravenously in phosphate buffer (IVPB) q 12 h or gentamicin 1.5 mg/kg IVPB q 8 h plus mezlocillin 4 g IVPB q 6 h. During surgery, gall bladder tissue, plasma, peritoneal fluid, and bile fluid samples were obtained at approximately the same time. Thirty-three patients had data acceptable for analysis. Values are given as mean +/- standard deviation. The mean delta time (defined as the time between the administration of cefepime and the time the samples were obtained) was 8.58 +/- 3.53 h. The values for plasma, peritoneal fluid, bile fluid, and gall bladder tissue concentrations were 7.63 +/- 14.17 micrograms/ml, 5.66 +/- 6.80 micrograms/ml, 15.51 +/- 16.94 micrograms/ml, and 5.36 +/- 6.57 micrograms/gm, respectively. The peritoneal fluid/plasma ratio was 2.10 +/- 2.33, the bile fluid/plasma ratio was 14.44 +/- 31.99, and the gall bladder tissue/plasma ratio was 1.44 +/- 1.82. There was a significant correlation between peritoneal fluid and plasma concentration (r = 0.91, p less than 0.0005), and gall bladder tissue and plasma concentration (r = 0.90, p less than 0.0005). There was no correlation between bile fluid and plasma cefepime concentrations. The minimum inhibitory concentration (MIC) data from previous in vitro studies indicate that cefepime concentrations achieved in this patient population would be adequate against typical biliary tract pathogens.(ABSTRACT TRUNCATED AT 250 WORDS)

Epidemiological spectrum and current treatment of listeriosis

To reassess the epidemiology and treatment of listeriosis in the United States, we reviewed greater than 120 cases of listeriosis from four medical centers in three geographically separated cities: Los Angeles County-University of Southern California Medical Center (LAC-USCMC); Rush-Presbyterian-St. Luke's Hospital, Chicago; the University of Illinois Hospital, Chicago; and Vanderbilt University Hospital, Nashville, Tennessee. The epidemiological pattern at LAC-USCMC was relatively narrow; more than two-thirds of the cases occurred during the perinatal period. Cases at Vanderbilt University Hospital represented the opposite end of the spectrum; the majority of these occurred in nonpregnant, older adults who had received organ transplants. An intermediate pattern of cases was observed at the two medical centers in Chicago. Potential risk factors included pregnancy, neonatal status, organ transplantation, renal failure, malignancy, systemic lupus erythematosus, steroid therapy, and AIDS (two cases). Antimicrobial agents noted to be effective were, as expected, penicillin and ampicillin; the cephalosporins were ineffective. The mortality associated with listeriosis occurred mainly among premature infants and stillbirths delivered from infected pregnant women and was markedly less among neonates and adults.

Susceptibility testing of Listeria monocytogenes. A reassessment of bactericidal activity as a predictor for clinical outcome

In vitro susceptibility testing of Listeria monocytogenes most often reveals both ampicillin and penicillin as inhibitory as opposed to bactericidal with activity comparable to chloramphenicol and tetracycline. Yet, the former two penicillins are more effective for Listeria meningitis than are the latter agents. Accordingly, we reassessed the bactericidal activity of agents used in listeriosis in order to determine in vitro methodology that would be more predictive of clinical outcome. We found that bactericidal activity for greater than 48 hr by either minimum inhibitory-minimum bactericidal concentration (MIC-MBC) testing or time-kill kinetic studies was the best predictor of clinical efficacy. This correlation may be due to Listeria being a slow-growing microorganism. In addition to ampicillin and penicillin, we found trimethoprim-sulfamethoxazole, vancomycin, and imipenem to exhibit bactericidal activity for 48 hr. For the first two agents, this is in agreement with the results of clinical experience.

Intramuscular imipenem as adjuvant therapy for acute cholecystitis and perforated or gangrenous appendicitis

An open-label prospective study was performed employing intramuscularly administered imipenem as an adjunct to surgery in 20 patients with acute cholecystitis and 24 patients with perforated or gangrenous appendicitis. Three (12.5%) septic failures occurred in appendicitis patients and 2 (10%) failures in cholecystitis patients. There were no deaths. Adverse effects were minor, and there was no toxicity. Although failures were not associated with in vitro resistance, Pseudomonas spp. were recovered from 2 of 3 appendicitis failures. Intramuscular imipenem appeared to be an effective single-drug antimicrobial when used as an adjunct to surgery in patients with acute cholecystitis or perforated appendicitis. It should be a more cost-effective alternative to the current multiple-drug therapy frequently employed in patients with intra-abdominal sepsis.

Epidemiology, antimicrobial susceptibility, pathogenicity, and significance of Bacteroides fragilis group organisms isolated at Los Angeles County-University of Southern California Medical Center

The epidemiology of species of the Bacteroides fragilis groups isolated at Los Angeles County-University of Southern California Medical Center was examined. In addition, frequency of resistance to six beta-lactam antibiotics (cefmetazole, cefotetan, ceftizoxime, imipenem, penicillin, and cefoxitin) and to clindamycin, chloramphenicol, and metronidazole was determined for each species. While B. fragilis was most commonly isolated, the other species of the B. fragilis group accounted for half of the isolates. Seven percent of 1,128 patients with infections due to species of the B. fragilis group were bacteremic. A review of bacteremic cases indicated that non-fragilis species were highly pathogenic. Resistance to clindamycin ranged from 8% to 22% among species and was most common among isolates of Bacteroides distasonis and Bacteroides thetaiotaomicron. Significant differences in antimicrobial activity were noted among the agents tested. Only imipenem, chloramphenicol, and metronidazole were predictably effective against non-fragilis species of the B. fragilis group. Prompt identification of species and susceptibility testing of clinical isolates of this group are needed if a newer beta-lactam agent or clindamycin is to be used for initial therapy.

Transmission of parasitic and bacterial infections through blood transfusion within the U.S

The American public has become aware that viral infections can be transmitted by blood transfusions; however, less attention has been paid to nonviral agents that are similarly transmitted. Although donors are tested routinely for serologic evidence of Treponema pallidum infection (syphilis), there are no other bacterial infections for which donors are routinely tested, and no testing is done routinely to detect parasitic infections. Although current preventive strategies appear effective in preventing the transmission of nonviral agents by transfusion, changing population demographics, increased travel and immigration, and increased occurrence of certain asymptomatic bacterial infections in blood donors may require new policies to maintain the safety of the U.S. blood supply. This review focuses on the parasitic and bacterial infections that might pose a risk to transfusion recipients in the U.S.

Intraoperative concentrations of ofloxacin in serum, bile fluid, and gallbladder wall tissue

To evaluate concentrations of ofloxacin in serum, bile fluid, and gallbladder wall tissue after intravenous administration, patients greater than or equal to 16 years old diagnosed with acute cholecystitis were randomly assigned to receive ofloxacin (400 mg) intravenously every 12 h or ceftazidime (2 g) intravenously every 8 h. Doses of each regimen were given preoperatively. Serum, bile fluid, and gallbladder wall tissue samples of consecutive patients in the ofloxacin group were obtained intraoperatively. The samples were frozen at -70 degrees C until analyzed by high-pressure liquid chromatography. Twenty-three patients (6 males and 17 females) were evaluated. The mean (+/- the standard deviation) ofloxacin concentrations in serum, bile fluid, and gallbladder wall tissue were 2.9 +/- 2.4 and 6.0 +/- 7.9 micrograms/ml and 3.1 +/- 2.9 micrograms/g, respectively. The mean number of doses each patient received before surgery was 5.3 +/- 3.0, and the mean delta time (time elapsed between last antibiotic administration and when intraoperative samples were obtained) was 9.6 +/- 7.5 h. The mean tissue-to-serum ratio was 1.2 +/- 0.5, and the mean bile-to-serum ratio was 2.3 +/- 1.4. The mean serum ofloxacin concentrations were not statistically different from the concentrations in bile (P = 0.1) and tissue (P = 0.7) at the mean delta time. The study revealed that concentrations of ofloxacin in serum, bile fluid, and gallbladder tissue after intravenous dosing were adequate against susceptible organisms found in the biliary tract.

Ceftazidime/clindamycin versus tobramycin/clindamycin in the treatment of intra-abdominal infections

In order to assess the efficacy and toxicity of ceftazidime as a substitute for aminoglycosides in the treatment of intra-abdominal sepsis, a prospective randomized trial was conducted. Ninety-four patients (49% trauma) were randomized to receive ceftazidime/clindamycin (CAZ/C) (n = 47) or tobramycin/clindamycin (T/C) (n = 47). CAZ (2.0 gm) and C (0.9 gm) were administered intravenously every 8 hours while T dosage was adjusted to maintain peak (5-8 mg/L) and trough (less than 2 mg/L) concentrations. Age, sex, baseline serum creatinine, and etiology of infection were comparable in the two groups. Clinical cure was similar in culture-positive and culture-negative patients who received CAZ/C (94% vs 88%). The clinical cure rate however was significantly lower in the T/C culture positive (73%) than in the culture negative patients (100%) (P = 0.016). Pathogenic organisms were eradicated in 100% (30/30) and 76% (13/17) of CAZ/C and T/C patients, respectively (P = 0.0006). Nephrotoxicity Nephrotoxicity or ototoxicity was observed in none of the CAZ/C patients and in one and two T/C patients, respectively. CAZ/C more effectively eradicated the bacteria isolated from these patients and no significant difference in clinical response was observed in culture-positive patients. These findings plus the lack of toxicity suggest that CAZ/C is an effective alternative for treatment of IAI.

Treatment of intra-abdominal infections: cost comparison of ampicillin/sulbactam and clindamycin/gentamicin

The cost of 2 g ampicillin/1 g sulbactam given IV piggyback qid was compared with 900 mg clindamycin admixed with 1.5 mg/kg gentamicin given IV piggyback tid for the treatment of perforated or gangrenous appendicitis in 116 patients. Fifty-eight ampicillin/sulbactam-receiving patients incurred greater costs for IV supplies (+104.6/patient vs +67.9/patient) and nursing administration costs (+16.5/patient vs +10.7/patient). On the other hand, pharmacist and technician preparation costs were greater for the 58 clindamycin/gentamicin-receiving patients (+15.4/patient vs +13.3/patient). The clindamycin/gentamicin-receiving patients also incurred additional changes for laboratory fees and pharmacokinetic monitoring--+18.7/patient and +36.1/patient, respectively. When incorporating all cost parameters, there were no statistically significant differences in mean total drug therapy costs between the two treatment regimens--+433.3 +/- +58.5/patient for ampicillin/sulbactam and +373.8 +/- +86.2/patient for clindamycin/gentamicin.

Controlled comparison of cefmetazole with cefoxitin for prophylaxis in elective cholecystectomy

Prophylactic antibiotics are given routinely to patients undergoing surgical treatment of the biliary tract to prevent postoperative infection if risk factors for postoperative sepsis are present. Cefmetazole (CM) is a new broad spectrum parenteral cephamycin antibiotic. This drug possesses a spectrum of activity against a wide range of gram-negative and gram-positive bacteria that is similar to cefoxitin (CX), an antibiotic widely used for prophylaxis with operations upon the abdomen. In this study, there was a random selection of two patients to receive CM to every one patient to receive CX. The dose of CM was 1 gram given intravenously every eight hours for three doses beginning 30 minutes before the operation; three doses of CX were given intravenously, 2 grams every six hours. Fifty-two evaluable patients comprised the CM group and 26, the CX group. The risk factors for postoperative infection were acute cholecystitis (CM, seven patients; CX, one patient), evidence from imaging procedure suggesting need for exploration of the common duct (CM, six; CX, one), hyperbilirubinemia (CM, eight; CX, four), hyperamylasemia (CM, 17; CX, seven); age of 60 years or more (CM, six; CX, one), obesity (CM, 36; CX, 14) and diabetes mellitus (CM, four; CX, five). Operative bactibilia and the organisms were comparable in both groups. Postoperative days of fever greater than or equal to 38 degrees C. (oral) (CM, 0.83 +/- 1.20; CX, 0.58 +/- 0.96) and hospitalization (CM, 6.59 +/- 2.20; CX, 5.04 +/- 1.26) were similar. Postoperative septic complications at the operative site occurred in two patients in the CM group (4 per cent) and in none of the patients in the CX group (p = 0.4; N.S., Fischer exact test). These two antibiotics had similar efficiency in preventing postoperative infections.

Prevalence of Helicobacter pylori infection and histologic gastritis in asymptomatic persons

We estimated the prevalences of Helicobacter pylori (formerly called Campylobacter pylori) infection and histologic gastritis in 113 asymptomatic persons, using endoscopic biopsy of the gastric antrum and corpus. Unsuspected lesions, mainly mucosal erosions, were revealed at endoscopy in 16 subjects (14 percent). Gastritis was found in 42 subjects (37 percent), of whom 36 (32 percent of the total) were found to be infected with H. pylori on the basis of hematoxylin-eosin staining. H. pylori was not found in any of the 71 subjects with normal histologic features. Gastritis and H. pylori were noted in both the antrum and corpus in 75 percent of those infected (n = 27). The prevalence of H. pylori infection increased from 10 percent (2 of 20 subjects) in those between the ages of 18 and 29, to 47 percent (7 of 15) in those between the ages of 60 and 69, but the effect of age did not reach statistical significance. The prevalence of gastritis increased significantly with advancing age. Stepwise logistic regression analysis revealed that the relative risk for H. pylori infection associated with recent (within six months) antibiotic use was 5.8 (95 percent confidence interval, 1.5 to 22.1), whereas the relative risk was 6.5 (95 percent confidence interval, 1.4 to 29.2) for those who had never used bismuth compounds. We conclude that histologic gastritis and H. pylori infection commonly occur in the stomach of apparently normal persons and increase in prevalence with advancing age. All the subjects with H. pylori infection had gastritis, suggesting a possible etiologic role for the bacterium in the histologic lesion.

Cost analysis of two clindamycin dosing regimens

A clinical trial of clindamycin 900 mg q8h admixed with gentamicin 1.5 mg/kg (eight-hourly group) versus clindamycin 600 mg q6h with gentamicin 1.5 mg/kg given separately (six-hourly group) was analyzed for relative cost containment. Acquisition costs were significantly higher for the six-hourly group for intravenous supplies ($181.5 +/- 47.8) when compared with the eight-hourly group ($67.6 +/- 21.6) (p less than 0.05). Nursing administration costs were greater for the six-hourly group ($28.6 +/- 7.5) compared with ($10.7 +/- 3.4) for the eight-hourly group (p less than 0.05). Also, significantly higher cost (p less than 0.05) was noted for pharmacist and technician manufacturing cost for the six-hourly group ($15.4 +/- 4.0) compared with the eight-hourly group ($13.3 +/- 4.3). Incorporating all appropriate costs, the mean total drug therapy costs were significantly greater (p less than 0.05) for clindamycin 600 mg q6h ($527.4 +/- 143.0) compared with clindamycin 900 mg q8h ($433.3 +/- 99.2). The dosing of clindamycin 900 mg q8h admixed with gentamicin 1.5 mg/kg is a more cost-effective method of drug delivery with similar efficacy and safety when compared with clindamycin 600 mg q6h with gentamicin given separately.

A cost comparison of intramuscular versus intravenous imipenem

Previously reported clinical trials of imipenem-cilastatin 500 mg given intravenously every 6 hours (intravenous group) and imipenem-cilastatin 750 mg given intramuscularly every 12 hours (intramuscular group) were analyzed for relative cost savings. Acquisition costs were significantly higher for the intravenous group for intravenous supplies (30.6 +/- 7.9 dollars) when compared to the intramuscular group (0.98 +/- 0.03 dollars) (p less than 0.05). Also, significantly higher cost (p less than 0.05) was noted for salaries of pharmacists and technicians for manufacturing in the intravenous group (5.8 +/- 1.5 dollars) as compared to the intramuscular group (2.4 +/- 0.7 dollars). Nursing administration costs were greater for the intramuscular group (15.6 +/- 4.8 dollars) when compared to the intravenous group (11.7 +/- 3.0 dollars). Incorporating all appropriate costs, the mean total drug therapy costs (TRX$) were significantly greater (p less than 0.01) for the intravenous group (458.17 +/- 175.17 dollars) as compared to the intramuscular group (298.0 +/- 114.76 dollars). Thus, the dosing of imipenem-cilastatin 750 mg intramuscularly every 12 hours is a more cost effective method of drug delivery with equal efficacy and safety when compared to imipenem-cilastatin 500 mg given intravenously every 6 hours.

Detection of cytomegalovirus DNA in peripheral blood of patients infected with human immunodeficiency virus

Detection of cytomegalovirus (CMV) DNA can be facilitated by the polymerase chain reaction (PCR), an in vitro gene amplification technique. Twenty-eight CMV tissue culture isolates were examined by amplification of two separate CMV genes. All were found to contain CMV, although two of the isolates were positive for only one of the two genes. No detectable amplification occurred with human genomic or other viral DNA controls. The amplification products from as few as one CMV plaque-forming unit could be detected after the PCR. CMV DNA was detected in the blood of 14 of 27 patients with AIDS and one of six patients who were infected with human immunodeficiency virus but who did not have AIDS. Normal CMV-seropositive or -seronegative individuals did not have CMV DNA detected in their blood. The CMV PCR was more sensitive than the standard culture assay, can be completed in one to two days, uses only 20 microL of blood, and may be useful for rapidly detecting CMV in clinical specimens.

Prevalence of gastric metaplasia, inflammation, and Campylobacter pylori in the duodenum of members of a normal population

Mucosal biopsies were obtained from 116 asymptomatic volunteers (50% were male; mean age, 46 years; age range, 19-91 years) to study the prevalence of duodenal gastric metaplasia (GM) and its association with inflammation and Campylobacter pylori in a normal population. GM was identified in 25 subjects (22%). Eighty-three subjects (72%) had histologic duodenitis, but in only 10 did the infiltrate include neutrophils (grade 2 duodenitis). C. pylori was found in the stomach in 36 subjects (31%), all of whom had gastritis, but was not identified histologically in the duodenum. There were no significant differences between the overall frequency of duodenitis and either GM or antral C. pylori. Although the frequency of severe (grade 2) duodenitis was not significantly different between those with and those without GM, grade 2 duodenitis was found in 9 of 36 subjects with antral C. pylori but in only 1 of 80 without antral C. pylori (P less than 0.001). These findings suggest that gastric metaplasia is a common finding in the normal population and that grade 1 duodenitis is most likely clinically unimportant, whereas grade 2 duodenitis is usually associated with antral C. pylori.

Prevalence of Campylobacter pylori and association with antral mucosal histology in subjects with and without upper gastrointestinal symptoms

To determine the incidence and significance of Campylobacter pylori in patients undergoing routine endoscopic evaluation at this hospital, biopsies of the antrum were obtained from 132 patients and from 15 asymptomatic volunteers. Specimens were cultured and silver stained for the presence of C. pylori and were examined histologically. C. pylori was detected in 67 (51%) patients and two (13%) volunteers (P = 0.006). In patients, C. pylori was found significantly more often when the mucosa was inflamed (67%) than when the mucosa was normal (13%), and both volunteers with C. pylori had chronic gastritis on histological examination. When compared to the volunteers, patients with upper gastrointestinal symptoms had a significantly increased prevalence of antral inflammation, even if the endoscopic examination was normal. C. pylori is infrequently found in young asymptomatic adults but is found in both asymptomatic volunteers and patients in association with all forms of histological antral gastritis which is prevalent in patients with both normal endoscopic findings and peptic ulcer disease.

Potential of topical norfloxacin therapy. Comparative in vitro activity against clinical ocular bacterial isolates

Norfloxacin, a new fluoroquinolone antibiotic related to nalidixic acid, was evaluated as a topical agent for clinical efficacy in bacterial eye infections. This study reports on the comparative in vitro activity of norfloxacin and ten topical antibiotics (nalidixic acid, polymyxin B, colistin, bacitracin, chloramphenicol, sulfamethoxazole, tetracycline, erythromycin, gentamicin, and tobramycin) against 203 pathogenic eye isolates of 17 genera (37 species). In general, norfloxacin had the greatest potency and broadest spectrum of activity of the agents tested. It was active against Staphylococcus aureus (minimal inhibitory concentration against 90% [MIC90], less than or equal to 1.0 microgram/mL), coagulase-negative staphylococci (MIC90, less than or equal to 1.0 microgram/mL), Pseudomonas aeruginosa (MIC90, less than or equal to 1.0 microgram/mL), and Haemophilus organisms (MIC90, less than or equal to 1.0 microgram/mL).

Surgically treated gangrenous or perforated appendicitis. A comparison of aztreonam and clindamycin versus gentamicin and clindamycin

A randomized, double-blinded, controlled clinical study of 84 patients with surgically treated gangrenous or perforated appendicitis was done to compare the efficacy of the combination of aztreonam, the first monobactam antibiotic, with gentamicin when either was combined with clindamycin. Fifty-six patients who were treated with aztreonam and clindamycin (A/C) and 28 patients who were treated with gentamicin and clindamycin (G/C) fulfilled criteria for evaluation. A matched historic control group of 56 G/C patients was also included for comparison. All measures of outcome, including days of fever, hospitalization, antibiotic therapy, and the incidence of antibiotic failures, were similar. It was concluded that aztreonam was as effective as gentamicin in this study and may offer some advantages with regard to toxicity and serum drug level monitoring.

Matched case-control study of adjusted versus nonadjusted gentamicin dosing in perforated and gangrenous appendicitis

A matched case-control study of the efficacy of gentamicin dosage adjustment through the use of pharmacokinetic analysis of serum drug concentrations in patients treated by appendectomy for perforated or gangrenous appendicitis was performed. Two groups of patients were compared. In one group gentamicin was initiated preoperatively at 1.5 mg/kg Intravenous Piggy Back (IVPB) every 8 h. Postoperatively, serum levels were obtained to maintain peak concentrations within a range of 6-8 micrograms/ml. The comparison group was given gentamicin without measurement of drug levels. Both groups received clindamycin 600 mg IVPB every six h. Matched cases and control subjects were compared, controlling for pathologic state of the appendicitis, age, and sex. The patients were predominantly young men with normal renal function. More patients in the nonadjusted group had infectious complications than in the dose-adjusted group. There were seven failures (11.3%) in the nonadjusted group compared with only one failure (1.6%) in the dose-adjusted group, a significant difference (p = 0.03). Among the nonadjusted group, the complications were four abdominal abscesses, two wound infections, and one persistent high fever. There was no evidence of nephrotoxicity in either group. Our recommendations are that patients who are to undergo appendectomy for perforated/gangrenous appendicitis should be treated with clindamycin and gentamicin at a dose of 1.5 mg/kg. With normal renal function, an interval of 8 h is appropriate. Serum gentamicin levels should be obtained and the dose adjusted to maintain peak concentrations of 6-8 micrograms/ml.

In vitro contamination of "piggyback/heparin lock" assemblies: prevention of contamination with a closed, positive locking device (Click-Lock)

Direct contact and airborne transmission are established modes of microbial contamination of standard intravenous (iv) assemblies such as piggyback and heparin lock. In this study, 60% of the standard iv assemblies inoculated with Staphylococcus aureus (S. aureus) at the barrel of their exposed needle grew these organisms when cultured in a Soy Casein Digest Broth (SCDB). Also, 40 closed, positive locking iv assemblies (Click-Lock) were inoculated at possible contamination sites, and none of these assemblies grew S. aureus in a SCDB. These in vitro studies suggest that a closed, positive locking iv assembly such as the Click-Lock device may substantially reduce, and potentially prevent contamination of iv systems.

A case of melioidosis originating in North America

A case of melioidosis is described in a patient from Mexico. The cases that have been previously reported to originate in the western hemisphere are critically reviewed. The clinician must be aware of this rare disease because its treatment is quite different from that of other gram-negative infections.

The efficacy of cefoxitin vs. clindamycin/gentamicin in surgically treated stab wounds of the bowel

A randomized, double-blind study of cefoxitin (CX) or clindamycin/gentamicin (CG) as adjuncts to the surgical management of peritonitis is reported. Groups with similar infection risks were evaluated by including only patients with abdominal stab wounds, enteric injury, and spillage of the gastrointestinal contents. One hundred ninety-five patients were entered of whom 75 were evaluable. Comparisons of the ages, sex, diagnoses, and measures of outcome were not significantly different. Fifteen per cent (5/34) of CX treated patients had postoperative complications (three infections) vs. 10% (4/41) of patients treated with CG (three infections). Intraperitoneal bacteria were cultured from 62% of CX and 59% of CG patients. Antibiotic resistance, seen in three patients of each group, was not associated with failure. Two moderately sensitive Bacteroides distasonis were each associated with a failure in the CX and CG groups. We deduce that both regimens are effective and that cefoxitin may represent less costly single-agent therapy.

Cost analysis of antibiotics in the management of perforated or gangrenous appendicitis

Costs associated with treating patients for gangrenous or perforated appendicitis were compared. Patients received single agent therapy with cefoperazone or cefamandole or combination antibiotics consisting of clindamycin and serum level-adjusted gentamicin. Forty-eight patients received cefamandole, 47 received cefoperazone, and 52 received combination clindamycin and gentamicin. Costs to the pharmacy for drugs were greater for the combination therapy; however, the higher failure rate associated with the cephalosporins created greater expenses for the single agent therapy than for combination therapy.

Imipenem therapy for perforated and gangrenous appendicitis

A matched patient control study of imipenem therapy of patients with perforated or gangrenous appendicitis was performed. Thirty-three patients treated with imipenem and cilastatin were compared with 66 control patients treated with clindamycin and gentamicin. Patients were matched for age and surgical pathologic factors. Twenty-five of the 33 imipenem treated patients had perforated (two with abscesses) and nine had gangrenous appendicitis. Anaerobes were recovered from 23 of 32 (72 per cent), anerobes from 31 of 32 (97 per cent) and Pseudomonas from six (26 per cent) of the 23 with perforated appendicitis. Only one isolate, a Fusobacterium species was resistant to imipenem. Enterococci were isolated only from three imipenem treated patients, all were susceptible and were not associated with failures. Frequency of other pathogens isolated was similar for the imipenem and clindamycin and gentamicin patients. One failure occurred in the imipenem treatment group. Failures and adverse reactions were not different for the two groups. The study would have detected as significant (p equals 0.03) a 9 per cent difference in failure rates. Mean days of fever of more than 38 degrees C and days of hospitalization were fewer (p less than 0.05) for imipenem treated patients even when only patients with perforated appendicitis were compared. Days to return of intestinal function were fewer for control patients. Imipenem and cliastatin appeared to be an effective antimicrobial agent used as an adjunct to surgical treatment for peritonitis associated with appendicitis even when caused by Bacteroides fragilis group organisms or Pseudomonas species, or both.

Perinatal mortality associated with intrauterine infection due to pseudomonads

Pseudomonads are common causes of nosocomial infections but are rarely implicated in perinatal disease. In a retrospective autopsy study we found that 9% of all acute congenital bacterial infections were due to Pseudomonas species. Premature rupture of membranes occurred in half the cases and clinical maternal amnionitis in two-thirds. One case was apparently nosocomial in origin. No known risk factors were implicated in any other case. Seven infants were stillborn and two died within a few hours. Congenital pneumonia, funisitis, and chorioamnionitis were found at autopsy. Intrauterine infection due to the pseudomonads poses a serious problem that has not been previously recognized.

The role of Pseudomonas species in patients treated with ampicillin and Sulbactam for gangrenous and perforated appendicitis

A prospective, randomized, double-blinded comparison of Sulbactam and ampicillin and clindamycin and gentamicin is described. The combination of ampicillin and Sulbactam was not as effective in the management of perforated appendicitis and gangrenous appendicitis as was clindamycin and gentamicin. While both combinations of antibiotics had good anaerobic activity and failures were not associated with the recovery of Bacteroides fragilis group organisms, infectious complications were seen in patients from whom Pseudomonas were isolated. These pseudomonads were not nosocomially acquired and were found especially in patients with perforated appendicitis. We concluded that the combination of clindamycin and gentamicin, although less convenient to administer to the patient, remains the adjunctive antibiotic management of choice for perforated or gangrenous appendicitis. The epidemiologic factors of Pseudomonas species as a primary pathogen in peritonitis deserves further attention.

Comparative in vitro activities of norfloxacin (MK-0366) and six commonly used antimicrobial agents against 199 urinary isolates showing various degrees of antibiotic resistance

The in vitro activity of norfloxacin (MK-0366), a new oral antimicrobial agent, was compared to that of ampicillin, tetracycline, cefazolin, nitrofurantoin, nalidixic acid, and trimethoprim against 199 gram-negative urinary isolates. Among these isolates were ampicillin-resistant Escherichia coli and gentamicin-resistant Pseudomonas aeruginosa and Serratia marcescens. Norfloxacin was the most active antimicrobial agent tested against all isolates studied; it was the only agent active against P. aeruginosa and S. marcescens.

Epidemiology and susceptibility of resistant Bacteroides fragilis group organisms to new beta-lactam antibiotics

The epidemiology of the Bacteroides fragilis group and the interspecies frequencies of antibiotic resistance were examined. Susceptibilities were determined for 16 beta-lactam antibiotics, including seven new compounds. Fourteen percent of 287 patients with infection due to organisms of the B. fragilis group presented with bacteremia. Infections were as common among pediatric patients as among patients on the surgical services. Clindamycin resistance varied from 3% to 22% among the species. Resistance to clindamycin and cefoxitin was more likely to be encountered among Bacteroides species other than B. fragilis. These organisms were more commonly recovered from surgical wound specimens. Only N-formimidoylthienamycin showed predictably good activity against Bacteroides resistant to clindamycin or cefoxitin. The other new beta-lactam antibiotics had variable activities against these resistant strains, and significant differences were noted overall among the antimicrobial agents tested. Early speciation and susceptibility testing of clinical isolates of the B. fragilis group are needed, particularly if newer agents with unpredictable activities are used.

Perforated and gangrenous appendicitis: an analysis of antibiotic failures

The relationships between resistant pathogens, serum levels of gentamicin, and the outcomes of gangrenous or perforated appendicitis were analyzed in 147 patients. Failure to cure the infection occurred significantly more frequently among patients treated with cefoperazone or cefamandole than among those treated with clindamycin and gentamicin in combination. The failures were associated with recovery of resistant Bacteroides fragilis from intraoperative cultures. Pseudomonas species were also associated with failures, their in vitro susceptibility not correlating with clinical cure. Patients with gentamicin peak serum levels of less than 6 micrograms/ml in the first three days were not more likely to be associated with failure than were patients with higher levels. These clinical observations indicate that antibiotic therapy of intra-abdominal sepsis should include antibiotics with in vitro activity against B fragilis and that precise adjustments of gentamicin levels may not improve outcome. In addition, Pseudomonas species may play a significant role in some of these infections.