In vitro sensitivity at 18 antibiotics of 192 strains of Pseudomonas aeruginosa isolated at Garches Hospital

The in vitro activity of 18 antibiotic (beta-lactam agents, quinolones and aminoglycoside has been evaluated against 192 clinical isolates of Pseudomonas aeruginosa. Minimal inhibitor concentrations (MICs) were determined by the agar dilution technique. The 50% and 90% MICs were respectively: ticarcillin (32/greater than 1 024), azlocillin (16/512), piperacillin (8/512), cefsulodin (4/128), ceftazidime (2/8), aztreonam (4/16), imipenem (2/4), nalidixic acid (128/256), pefloxacin (1/8), norfloxacin (1/8), ofloxacin (2/8), ciprofloxacin (0.25/2), gentamicin (8/256), sisomicin (4/256), tobramycin (2/128) dibekacin (4/256), netilmicin (16/256), amikacin (8/16). The sensitivity to beta-lactam agents and to quinolones was usual. Resistance to aminoglycosides was frequently observed (59%): 35.7% of the resistant isolates were resistant to gentamicin-sisomicin-tobramycin-dibekacin-netilmicin, 30% to netilmicin alone, 17.8% to gentamicin-sisomicin-tobramycin-dibekacin-netilmicin-amikacin, 7% to gentamicin-netilmicin, 5.3% to gentamicin-sisomicin-tobramycin-dibekacin; we did not find any P. aeruginosa resistant only to gentamicin or gentamicin-sisomicin.     

In vitro sensitivity to antibiotics of genital mycoplasmas isolated in Toulouse. Study of new molecules (macrolides and quinolones)]

The minimal metabolism-inhibiting concentrations (MMC) of 11 antibiotics were determined for 40 strains each of M. hominis and U. urealyticum using a terminal color change broth method. All strains were recovered in 1990. Resistance to tetracycline (MMC greater than 8 mg/l) was found for 12.5% of strains of M. hominis and U. urealyticum, as compared with 5% in 1985. Rokitamycin was the most active macrolide against M. hominis (MMC 90: 0.06 mg/l). U. urealyticum strains were susceptible to all the macrolides tested, with the greatest activities being seen for rokitamycin and clarithromycin (MMC 90: 0.06 mg/l and 0.12 mg/l respectively). Sparfloxacin was the most active quinolone against both species. Human clinical trials designed to evaluate these new molecules for the treatment of mycoplasmal and ureaplasmal genital infections are warranted.     

In vitro sensitivity of Chlamydiae to antibiotics

The in vitro activity of 11 antibiotics against 16 Chlamydia trachomatis strains isolated from genital tract and 2 Chlamydia psittaci strains isolated from pulmonary tract. The CMI determination (the lowest dilution of the drug which inhibited the inclusion development when untreated control give 10(3) IFC) was assessed by growth in cycloheximide treated McCoy cells-antibiotics were added after incubation for 2 hours at 37 degrees C. The CMI values for Chlamydia trachomatis and Chlamydia psittaci are similar. The activity of antibiotics by comparison between CMI90 and serial levels. The CMI90 (mg/l) were: doxycycline = 0.2, minocycline = 0.2, roxythromycine = 0.12, érythromycine = 0.5, spiramycine = 4, rifampicine = 0.016, ofloxacine = 4, ciprofloxacine = 4, pefloxacine = 8, lomefloxacine = 8, fleroxacine = 8. For Chlamydia trachomatis species all the strains have the same sensibility, no resistance was detected.     

In vitro sensitivity of Mycobacterium xenopi to five antibiotics

We tested 20 strains of Mycobacterium xenopi (M. xenopi) in order to evaluate their in vitro sensitivity to amikacine, clarithromycine, ethambutol, ofloxacine and rifampicin, by establishing minimal inhibitory concentration (MIC) on agar medium. MICs of amikacine, clarithromycine and ofloxacine are low, so that these antibiotics can be used in the treatment of M. xenopi infections. MICs of ethambutol are higher than seric concentrations. Though, its therapeutic use is due to its in vivo ability to enhance penetration of other antibiotics in mycobacteria. Strain sensitivity to rifampicin seems heterogeneous but the small number of tested strains does not entitle the exclusion of rifampicin from the treatment of M. xenopi infections.     

"In vitro" sensitivity of bacterial strains isolated from urine cultures in the period 1995/96

Urinary tract infections represent a very frequent pathology. An epidemiologic survey on 6632 urine samples has been performed in the years 1995/96 to verify the bacterial incidence and susceptibility to antimicrobial drugs in this period, and variations in the resistance patterns with respect to a previous study. The results suggest the importance of a constant epidemiological surveillance in the community setting.     

In vitro activity of tigecycline against strains isolated from diabetic foot ulcers

Purpose of the studyThe aim of this study was to evaluate the in vitro activity of tigecycline and other comparator agents against bacterial strains isolated from diabetic foot infections (DFI).Patients and methodsAll diabetic patients hospitalized for a first episode of DFI (stage 2 to 4, according to the International Working Group of Diabetic Foot classification) were selected in Nîmes University hospital between January 2005 and June 2006. MICs were determined using custom broth microdilution panels against bacterial strains isolated from foot samples.ResultsThree hundred fifteen strains were studied. Tigecycline was active against 83.7% of all the strains especially Gram-positive cocci (97.3%) in particular methicillin-resistant Staphylococcus aureus (96%), Enterobacteriaceae (88.5%) and anaerobes (100%). Exclusively Pseudomonas aeruginosa and Proteae were not covered by this antibiotic.ConclusionsTigecycline, a new broad spectrum antimicrobial agent, is qualified to belong to the therapeutic arsenal package of complicated skin and soft tissue infections in diabetic patients after microbial documentation.     

In vitro activities of eight antibiotics against methicillin-resistant S. aureus and S. epidermidis strains isolated in Korea

Staphylococcus aureus and Staphylococcus epidermidis strains isolated at eight large medical centers in Korea were examined for methicillin resistance and resistance to eight other antibiotics; cefazolin, cefamandole, cefuroxime, cefoxitin, cefotaxime, moxalactam, penicillin G and vancomycin. Methicillin resistance was found in 296 of 1225 strains (24.2%) of S. aureus and 126 of 348 strains (36.2%) of S. epidermidis. Methicillinresistant strains were isolated from all sources with the frequency of isolation ranging from 11% to 60%. From pleural effusion, throat swab and blood, methicillin-resistant strains of S. aureus were more frequently isolated with statistical significance (Chi-squared test, 95% confidence). Almost all of Methicillin-resistant S. aureus (MRSA) and S. epidermidis (MRSE) strains were multiply resistant to one or more tested eight antibiotics. However only 7(2.4%) of 296 MRSA strains and 2(1.6%) of 126 MRSE strains were resistant to vancomycin. Vancomycin was the most effective antibiotic against staphylococcal isolates as well as MRSA and MRSE.     

In vitro activity of antibiotics againstUreaplasma urealyticum andChlamydia trachomatis strains from patients with nongonococcal urethritis

The activity of minocycline, doxycycline, tetracycline, erythromycin, mepartricin and lincomycin against 35 freshly isolated Ureaplasma urealyticum strains was tested. Doxycycline was the most active. Twelve strains were resistant to minocycline and four of these were sensitive to erythromycin. Mepartricin showed no activity against the organisms at a concentration of 10 micrograms/ml. The susceptibility of 30 low-laboratory-passage Chlamydia trachomatis strains against tetracycline and erythromycin was tested. A variable degree of sensitivity to tetracycline and erythromycin was found, the median MIC values being 0.13 micrograms/ml and 0.025 micrograms/ml respectively. No resistant Chlamydia trachomatis strain was found.     

Resistance to antibiotics of vibrio cholerae strains isolated in Angola]

Among 87 strains of Vibrio choleare (78 Ogawa serotype and 9 Inaba serotype strains) isolated in Angola in 1987-1990, 86% exhibited multiple resistance to antimicrobials. Eighty-four to 86% of strains were resistant to ampicillin with beta-lactamase production (MIC greater than or equal to 512 mg/l), streptomycin (MIC greater than or equal to 64 mg/l), spectinomycin (MIC greater than or equal to 1,024 mg/l), and trimethoprime-sulfisoxazole (MIC greater than 1,024 mg/l). Seventy-four per cent of strains were resistant to kanamycin (MIC = 512 mg/l), 26% to chloramphenicol (MIC = 32 mg/l), 10% to tetracycline (MIC = 16 mg/l), and 10% to gentamycin (MIC greater than or equal to 32 mg/l). Transfer to E. coli K12 was associated with a substantial increase in expression of resistance to tetracycline and chloramphenicol (CAT type I), with MICs in the 128-512 mg/l range. Transfer rates to E. coli K12 of plasmids for the various resistance phenotypes were 10(-6)/10(-8). The size of the isolated plasmids was 100 Md in diameter and belonged to the incompatibility group inc 6-C.     

Pathogenicity for chickens of six strains of mycoplasma gallisepticum isolated from various birds

Pathogenicity of the type strain and five field strains of Mycoplasma gallisepticum isolated from various avian hosts was evaluated by chicken inoculation. Only two field strains isolated from chickens were highly pathogenic for the chicken respiratory tract.     

In vitro activity of Septivon-Lavril toward mycoplasma pathogenic to humans

Septivon-Lavril is bactericidal in vitro towards species of mycoplasmas responsible for vaginal infections and their complications (U. urealyticum and M. hominis) and for the Stevens-Johnson syndrome (M. pneumoniae). As the active doses are inferior to those recommended for external use, this product, Trichlorocarbanilide, presents a clinical interest.     

Multicenter study of the sensitivity to beta-lactam antibiotics of 1,707 strains of Pseudomonas aeruginosa isolated at a general hospital

1,707 non replicate clinical strains of Pseudomonas aeruginosa from non teaching hospitals were investigated. Beta-lactam antibiotics were tested by agar disk diffusion method. Variance analysis revealed a significant interaction between strains and experimental laboratories. The bacterial population was grouped according to the diameters of inhibition zones of antibiogram, into five phenotypes. Pseudomonas aeruginosa is frequently isolated from urines and pulmonary sampling, rarely from blood cultures. Resistance to beta-lactams increased significantly with the duration of hospitalisation, and age of patients. Clinical strains are significantly more resistant in blood cultures, and for strains isolated from reanimation. 84% of strains are susceptible to ticarcillin.