Antimicrobial susceptibility of Aeromonas species isolated from patients with diarrhea

The MICs of various beta-lactams for 182 isolates of Aeromonas species, i.e., A. hydrophila (n = 101), A. sobria (n = 69), and A. caviae (n = 12), from clinical and environmental sources were determined by an agar dilution technique. All strains were resistant to ampicillin and susceptible to aztreonam. A. sobria and A. caviae demonstrated lower resistance rates than A. hydrophila. Penicillin-hydrolyzing beta-lactamases were detected in all strains.

“…resistant to 3-lactams are resistant to penicillins (16). However, some interspecies differences in susceptibility were observed with cephalosporins (9,15).…”

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confidence: 99%

“…The role of antibiotic therapy in the management ofAeromonas infections has not yet been defined (14,15), although the antibiotic resistance in motile Aeromonas spp. is an important problem for therapy directed to these organisms.…”

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confidence: 99%

beta-Lactam resistance of motile Aeromonas isolates from clinical and environmental sources

Morita

Watanabe

Kurata

et al. 1994

“…Inducible 1-lactamase activity has been associated with resistance to penicillin and many of the early cephalosporins in clinical isolates ofAeromonas spp. (10,23,30,33). We recently reported the existence of two apparently distinct inducible ,B-lactamases in Aeromonas sobria and A. hydrophila (1).…”

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confidence: 99%

“…as enteric pathogens in humans has increased in recent years, in part because of better methods and isolation techniques. These bacteria are implicated in a wide spectrum of enteric diseases ranging in clinical severity from mild diarrhea to acute gastroenteritis in both pediatric and adult populations (9,14,17,20,30,35). Furthermore, various Aeromonas species can be isolated from individuals with wound infections (17,18), and recovery of these organisms from severe infections, like septicemia, often involves patients with other underlying illnesses (3,18,19).…”

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confidence: 99%

Purification and characterization of inducible beta-lactamases in Aeromonas spp

Iaconis

Sanders

1990

13-Lactamases from Aeromonas hydrophila and A. sobria were purified and characterized. Both species produced 1-lactamases that were inducible by either cefoxitin or imipenem. These species were resistant to ampicillin and cephalothin but not imipenem. Isoelectric focusing of sonic extracts revealed one band at pl 8.0 and a second band at pl 7.0 for A. hydrophia. Likewise, A. sobria produced two bands, one at pI 8.4 and the other at pl 7.0. Two enzymes from each species were separated by flatbed electrofocusing gel and purified to homogeneity. The molecular weight of the pI 7.0 enzyme (Al) from both species was estimated to be 42,500, whereas the pI 8.0 (A2h) and 8.4 (A2s) enzymes ofA. hydrophila and A. sobria had molecular weights of 31,500 and 35,000, respectively, on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The relative Vm,.values for cephalothin, penicillin, and imipenem for these enzymes indicated that Al was primarily a cephalosporinase while A2h and A2s were penicillinases highly active against carbapenems. Al was susceptible to inhibition by cloxacillin, while the A2 enzymes were inhibited by clavulanic acid and EDTA and required zinc for activity. Thus, there appear to be two distinct inducible 1-lactamases in A. hydrophila and A. sobria that play an important role in the 13-lactam resistance of these species.

“…Vibrio alginolyticus (10) Aerononas caviae (12) Aeromonas hydrophila (12) Aeromonas sobnia (12) Plesiomonas shigelloides (12) Yersinia enterocolitica (9) Yersinia pseudotuberculosis (3) (6) 4 (6) .0.03 (6) 0.06, 0.12, 0.25 (2), 0.5 (2) . .0.03-0.12 [4][5][6][7][8][9][10][11][12][13][14][15][16] .0.03-0.12 c Toxin negative (n = 5); enterotoxinogenic E. coli: heat labile (n = 3), heat stable and heat labile (n = 3).…”

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confidence: 99%

In vitro activities of Ro 40-6890 against 164 predominantly intestinal members of the families Enterobacteriaceae and Vibrionaceae

Hohl

Zollinger-Iten

Graevenitz

1992

The in vitro activities of Ro Ro 40-6890 is the active moiety of a novel cephalosporin ester, Ro 41-3399 (7). It is inhibitory against a broad spectrum of aerobic gram-positive and gram-negative organisms (1). In the present study, we tested its in vitro potencies against predominantly intestinal bacteria of the families Enterobacteriaceae and Vibrionaceae (Vibrio spp.,Aeromonas spp., and Plesiomonas shigelloides). Test strains were single-patient isolates. They were identified by published methods (2) but were not bio-or serogrouped to strengthen their respective pathogenic links to enteropathogenicity (2, 14). We included cefotaxime, cefadroxil, and the amoxicillin-clavulanic acid combination in our testing.A total of 164 clinical isolates (at least 16 species; Salmonella spp. were counted as only one species pending redefinition of the concept of species within the genus) from the culture collection of the Department of Medical Microbiology at the University of Zurich were chosen for the study.The MICs of Ro 40-6890 and the comparative drugs were evaluated by the agar dilution method recommended by the National Committee for Clinical Laboratory Standards (10) with non-cation-adjusted Mueller-Hinton agar. The MICs were read with the naked eye and defined as the lowest concentration of antibacterial agent that inhibited clearly discernible bacterial growth. The growth of five or fewer colonies per plate was disregarded.Ro 40-6890 laboratory powder (lot no. 6069128; potency, 917 jig/mg; courtesy of C. Hubschwerlen) was synthesized at F. Hoffmann-La Roche Ltd., Basel, Switzerland, adjusted for potency deviation, and constituted in sterile water. Cefotaxime, cefadroxil, and amoxicillin were obtained from commercial sources; clavulanic acid was a gift from SmithKline Beecham, Beckenworth, United Kingdom. For the evaluation of the combination amoxicillin-clavulanic acid, a fixed concentration of 2 ,ug of clavulanic acid per ml was used in conjunction with twofold serial dilutions of amoxi-* Corresponding author. The results of our trial demonstrated that the predominantly intestinal members of the families Enterobacteriaceae and Vibrionaceae (Vibno spp., Aeromonas spp., and P. shigelloides) were uniformly very susceptible to (MIC range, c0.03 to 2 p,g/ml; MIC for 50% of isolates [MIC501, 0.06 p,g/ml; MIC90, 0.12 ,g/ml) and cefotaxime, a widely prescribed parenteral aminothiazolyl cephalosporin (MIC range, cO.03 to 2 ,g/ml; MIC50, c0.03 p,g/ml; MIC90, 0.12 p,g/ml) ( Table 1). For 9 of the 16 species, results were superimposable, whereas for the 7 remaining species, the MICs of Ro 40-6890 were 1 to 2 dilution steps lower than those of cefotaxime. The only isolates for which the Ro 40-6890 MIC was 20.25 ,g/ml were limited to the following species (MIC [in micrograms per milliliter], number of isolates): Aeromonas caviae (0.25, 1; 0