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.

Adult↗

PubMedDate not supplied

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.

Ampicillin↗

PubMedDate not supplied

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.

Adult↗

PubMedDate not supplied

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.

Adult↗

PubMedDate not supplied

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.

Anti-Bacterial Agents↗

PubMedDate not supplied

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.

Culture Media↗