E. García Sánchez

Antibiotic susceptibility profile of Xanthomonas maltophilia in vitro activity of β-lactam/β-lactamase inhibitor combinations

Abstract The susceptibility of 42 strains of Xanthomonas (Pseudomonas) maltophilia to 37 antibiotics (mainly β-lactams, aminoglycosides, and fluorinated quinolones) was tested. Xanthomonas maltophilia was resistant to most β-lactams, with ceftazidime, moxalactam, and ICI-194008 being the most active ones. Aminoglycosides had a very modest activity, with quinolones showing only moderate activity against this species. Trimethoprim/sufamethoxazole was effective against all strains tested. We also tested the synergy of several β-lactam/β-lactamase inhibitors against X. maltophilia . Only aztreonam/clavulanic acid at 3:1, 1:1 and, mainly, 2:1 combinations had synergistic activity, decreasing the rate of resistance from 92.8% for aztreonam alone to 32.4% for aztreonam-clavulanic acid at 1:1 and 0% for aztreonam-clavulanic acid at 2:1.

In vitro activity of 79 antimicrobial agents against Corynebacterium group D2.

Corynebacterium group D2 (CGD2) is involved in urinary tract infections in patients with underlying predisposing factors. This microorganism is highly resistant to a number of antimicrobial agents. We tested the activities of 79 antimicrobial agents against CGD2. beta-Lactams, aminoglycosides, and macrolides were ineffective. Fluorinated quinolones showed irregular activities, ofloxacin being the most active one. Doxycycline, rifampin, and mainly glycopeptides (vancomycin and teicoplanin) were the most active antibiotics against CGD2.

In vitro activities of new oral beta-lactams and macrolides against Campylobacter pylori.

The in vitro activities of amoxicillin, cefuroxime, ceftetrame, cefetamet, cefixime, tigemonam, erythromycin, roxithromycin, and dirithromycin against 30 clinical isolates of Campylobacter pylori were determined by an agar dilution technique. Roxithromycin and amoxicillin (MICs for 90% of isolates tested, 0.01 and 0.06 micrograms/ml, respectively) were the most active antibiotics tested, but all strains were susceptible to all antimicrobial agents tested.

Susceptibilities of Brucella melitensis isolates to clinafloxacin and four other new fluoroquinolones.

The susceptibilities of 120 clinical isolates of Brucella melitensis and 3 reference strains of the same species to six fluoroquinolones (clinafloxacin, PD 117596, PD 131628, PD 138312, PD 140248, and ciprofloxacin) were examined by agar dilution MIC methodology. Clinafloxacin was the most active compound tested (MIC at which 50% of strains tested were inhibited [MIC50] and MIC90 of 0.06 micrograms/ml). Its level of activity was slightly higher than that of PD 117596 (MIC50 and MIC90 of 0.12 micrograms/ml). PD 131628 and ciprofloxacin were less active than clinafloxacin, with MIC50s ranging from 0.12 to 0.25 micrograms/ml and MIC90s of between 0.25 and 0.5 micrograms/ml for the two compounds. The activity levels of PD 138312 and PD 140248, with MIC50s ranging from 1 to 2 micrograms/ml and MIC90s of 4 to 8 micrograms/ml, were lower than those of the other fluoroquinolones tested.

In- Vitro Activity of Meropenem, a New Carbapenem, Against Imipenem-Resistant Pseudomonas aeruginosa and Xanthomonas maltophilia

The activity of meropenem, a new carbapenem, as well as imipenem, ceftazidime, aztreonam, tobramycin, amikacin and ciprofloxacin against 18 strains of Xanthomonas maltophilia and 23 strains of Pseudomonas aeruginosa resistant to imipenem was tested. All strains of X. maltophilia were resistant to both penems. Ceftazidime, tobramycin and ciprofloxacin were the most active antimicrobial agents against this specie. 17% of imipenem-resistant strains of P. aeruginosa were sensitive to meropenem. Ciprofloxacin, amikacin and aztreonam were the most effective agents against these strains.

Efficacy of 2 Regimens of Local Ciprofloxacin in the Treatment of Ear Infections

Oral ciprofloxacin is very active against the microorganisms usually isolated from ear infections, and it has been shown to provide effective therapy for acute ear infections. However, chronic ear infections show lower response rates with oral ciprofloxacin, and some studies have demonstrated the usefulness of local ciprofloxacin in these infections (Esposito et ai. 1990). We studied the efficacy of 2 regimens of local ciprofloxacin in the treatment of ear infections in adults.

A Mathematical Model to Study the Meningococcal Meningitis

Abstract The main goal of this work is to introduce a novel mathematical model to study the spreading of meningococcal meningitis. Specifically, it is a discrete mathematical model based on cellular automata where the population is divided in five classes: sus- ceptible, asymptomatic infected, infected with symptoms, carriers, recovered and died. It catches the individual characteristics of people in order to give a prediction of both the individual behavior, and whole evolution of population.

CA-Based Model for Hantavirus Disease between Host Rodents

A new mathematical model to simulate the hantavirus disease between a population of rodents is introduced. It is based on the use of a two-dimensional cellular automaton where the cells stand for uniform portions of the terrain and the state of each cell can be either empty (without any rodent), susceptible (there is only one susceptible rodent placed in it) or infected (there is one infected rodent in the cell). Simulations about the evolution of the different classes of cells and the number of susceptible and infected rodents are obtained and analyzed.