Assessment of the bactericidal activity of sparfloxacin, ofloxacin, levofloxacin, and other fluoroquinolones compared with selected agents of proven efficacy against Listeria monocytogenes.

The search for alternative therapeutic agents for listeriosis includes the quinolone group. Accordingly, the bactericidal activity of ciprofloxacin, levofloxacin, lomefloxacin, ofloxacin, sparfloxacin, and temofloxacin, in comparison with that of ampicillin and sulfamethoxazole-trimethoprim, was evaluated against Listeria monocytogenes at 24 and 48 h of incubation using time-kill kinetic methodology. The inhibitory concentrations for each agent fell into a narrow range comparable with ampicillin.

A case of Trichosporon beigelii endocarditis 8 years after aortic valve replacement.

We report a case of Trichosporon beigelii endocarditis in a 77-year-old diabetic man who presented with an embolic stroke 8 years ago after a porcine aortic valve replacement. He was treated successfully with amphotericin, rifampin, and replacement of the original porcine valve; however, he died suddenly 8 months later from unknown causes. Blood cultures 2 months prior to death were negative.

Multiply resistant Klebsiella pneumoniae strains from two Chicago hospitals: identification of the extended-spectrum TEM-12 and TEM-10 ceftazidime-hydrolyzing beta-lactamases in a single isolate.

Ceftazidime-resistant Klebsiella pneumoniae strains began to appear when ceftazidime usage was increased in two unrelated Chicago hospitals. These strains produced a beta-lactamase with an isoelectric point of 5.6 (RP-5.

The medical complications of drug addiction and the medical assessment of the intravenous drug user: 25 years later.

Purpose: To review changes in the medical complications of drug abuse that have occurred since the authors reviewed them 25 years ago.

Data Source: Manual search of the internal medicine and subspecialty literature of the past three decades that was selected by the authors.

Study Selection: Selected studies were of three types--baseline studies for the period ending in 1968, studies after 1968 that emphasized changes from baseline, and studies after 1968 that emphasized change (or the absence of change) and the manner in which clinicians conceptualized problems.

Comparative susceptibility of the Bacteroides fragilis group species and other anaerobic bacteria to meropenem, imipenem, piperacillin, cefoxitin, ampicillin/sulbactam, clindamycin and metronidazole.

The in-vitro activity of meropenem, imipenem, piperacillin, cefoxitin, ampicillin/sulbactam, clindamycin and metronidazole was determined against 395 strains of strict and facultative anaerobes, including Gardnerella vaginalis, Lactobacillus spp. and Mobiluncus spp. The activities of meropenem and imipenem were within one dilution of their MIC50 and MIC90 values.

Retroperitoneal abscess caused by Mycobacterium chelonae and treatment.

Objective: To report a case of retroperitoneal abscess caused by Mycobacterium chelonae and treatment.

Design: Case report.

Setting: Private community teaching hospital.

A comparison of antimicrobial activity of ofloxacin, L-ofloxacin, and other oral agents for respiratory pathogens.

The attainable inhibitory ratios (AR) for oral antibiotics were calculated by using literature reports of concentrations attained in respiratory secretions for amoxicillin-clavulanic acid (AMX/CA), ofloxacin (OFL), L-ofloxacin (L-OFL), cefuroxime (CEFU), ciprofloxacin (CIP), and enoxacin (ENO), and using microdilution minimum inhibitory concentration data of these antimicrobials against the common bacterial respiratory pathogens. AR of each antibiotic against the pathogens was expressed as multiples of the MICs achieved at the respiratory site. Bacteria tested included Staphylococcus aureus, group-A and group-B streptococci, Viridans streptococci, Streptococcus pneumoniae, Brahamella catarrhalis, Klebsiella pneumoniae, Eikenella corrodens, Haemophilus influenzae, H.

Pleurocerebral Nocardia in a patient with human immunodeficiency virus.

Objective: To report a case of Nocardia asteroides pneumonia and subsequent brain abscess in an immunocompromised host.

Setting: Private, community, teaching hospital.

Patient: A man readmitted to the hospital for a third time with a fatal brain abscess, after responding to (misdirected) therapy in previous admissions.

Escherichia coli resistant to ampicillin/sulbactam.

Escherichia coli strains resistant to ampicillin/sulbactam from hospitals in 4 different geographic locations were examined with respect to type and amount of beta-lactamase produced. A total of 5 strains was examined from each region. The isoelectric points of all of the involved beta-lactamases were 5.

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.

Comparison of the inoculum effect of cefoxitin and other cephalosporins and of beta-lactamase inhibitors and their penicillin-derived components on the Bacteroides fragilis group.

We compared the inoculum effects for 109 recent clinical isolates of the Bacteroides fragilis group of cefoxitin, cefotetan, ceftizoxime, ceftriaxone, and three beta-lactamase inhibitors (clavulanic acid, sulbactam, and tazobactam) and their penicillin-derived components. Bactericidal activity was assayed and morphologic changes were monitored for selected strains exhibiting a large inoculum effect. Ceftizoxime demonstrated the largest inoculum effect, followed by cefotetan and ceftriaxone.

Bactericidal effects of antibiotics on slowly growing and nongrowing bacteria.

Antimicrobial agents are most often tested against bacteria in the log phase of multiplication to produce the maximum bactericidal effect. In an infection, bacteria may multiply less optimally. We examined the effects of several classes of antimicrobial agents to determine their actions on gram-positive and gram-negative bacteria during nongrowing and slowly growing phases.

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.

An in-vitro and in-vivo comparison of the activity of beta-lactamase inhibitor combinations with imipenem and cephalosporins against Escherichia coli producing TEM-1 or TEM-2 beta-lactamase.

Reference strains of Escherichia coli (ampicillin-susceptible and -resistant ATCC strains, and known TEM-1 and TEM-2 beta-lactamase producers) were tested in vitro and in the in-vivo mouse thigh infection model against four beta-lactamase inhibitor compounds (BICs: amoxycillin/clavulanic acid, ampicillin/sulbactam, ticarcillin/clavulanic acid, and piperacillin/tazobactam), selected cephalosporins, and imipenem. The ATCC strains (ampicillin-susceptible and -resistant) were susceptible to the BICs in disc and MIC tests. Three or more logs of killing were observed at the NCCLS breakpoint concentrations.

Comparison of the inoculum effects of members of the family Enterobacteriaceae on cefoxitin and other cephalosporins, beta-lactamase inhibitor combinations, and the penicillin-derived components of these combinations.

We compared the inoculum effects of 105 recent clinical isolates of the family Enterobacteriaceae on cefoxitin, other cephalosporins, aztreonam, and three beta-lactamase inhibitors (clavulanic acid, sulbactam, and tazobactam) and their penicillin-derived components. Piperacillin and aztreonam showed the largest inoculum effect, and cefoxitin showed the smallest. The other cephalosporins tested (cefotetan, ceftizoxime, and ceftriaxone) showed an intermediate inoculum effect.

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.

Evaluation of two methods for overcoming the antibiotic carry-over effect.

The antibiotic carry-over effect occurs when antibiotic transferred onto the agar plate with the subcultured aliquot is sufficient to inhibit the growth of viable bacteria, and results in a falsely low MBC. This phenomenon was eliminated by widely streaking the transferred aliquot over at least one half of a 100 mm agar plate or by centrifugation and resuspension of the organisms in non-antibiotic-containing media prior to plating. Both methods require more effort than the current method of MBC determination, but can be performed in clinical laboratories and are thus highly recommended in the testing of organisms from endocarditis and meningitis patients.