Antimicrobial Susceptibility and Mechanisms of Resistance to Quinolones and β-Lactams in Acinetobacter Genospecies 3

100

121

A clinical strain of Acinetobacter calcoaceticus resistant to carbapenems was isolated from a blood culture sample from an inpatient in a hospital in Madrid (Spain) during a large outbreak of infection (affecting more than 300 inpatients), caused by a multidrug-resistant Acinetobacter baumannii clone. The carbapenem resistance in both the A. calcoaceticus and A. baumannii clones was due to a bla OXA-24 gene harbored in different plasmids. The plasmids were fully sequenced, revealing the presence of site-specific recombination binding sites putatively involved in mobilization of the bla OXA-24 gene. Comparison of plasmids contained in the two strains revealed possible horizontal transmission of resistance genes between the Acinetobacter species.

mentioning

confidence: 99%

OXA-24 Carbapenemase Gene Flanked by XerC/XerD-Like Recombination Sites in Different Plasmids from Different Acinetobacter Species Isolated during a Nosocomial Outbreak

Merino

Acosta²,

Poza

et al. 2010

100

121

“…baumannii complex. With the exception of genospecies 1, the other members of this complex have been involved in nosocomial infections and have the ability to spread in hospitals (3,9,19,23,25,26). Treatment of these nosocomial infections is becoming a problem because increasing resistance to antibiotics, especially in the case of A. baumannii.…”

mentioning

confidence: 99%

Characterization of the Carbapenem-Hydrolyzing Oxacillinase Oxa-58 in an Acinetobacter Genospecies 3 Clinical Isolate

Martí

Sánchez‐Céspedes

Blasco

et al. 2008

“…A wide range of molecular mechanisms, such as the presence of ␤-lactamases, dihydrofolate reductase, Chl acetyltransferase (CAT) enzymes and many others (7,10,11,22,27), have been described. However, few studies have investigated molecular mechanisms of antimicrobial resistance among isolates from sub-Saharan Africa, due mainly to the limited number of laboratories and research facilities with an adequate infrastructure available on the continent (10,21).…”

mentioning

confidence: 99%

Antimicrobial Susceptibility and Mechanisms of Resistance in Shigella and Salmonella Isolates from Children under Five Years of Age with Diarrhea in Rural Mozambique

Mandomando

Jaintilal

Pons

et al. 2009

The antimicrobial susceptibility and mechanisms of resistance of 109 Shigella and 40 Salmonella isolates from children with diarrhea in southern Mozambique were assessed. The susceptibility to seven antimicrobial agents was tested by disk diffusion, and mechanisms of resistance were searched by PCR or colorimetric method. A high proportion of Shigella isolates were resistant to chloramphenicol (Chl) (52%), ampicillin (Amp) (56%), tetracycline (Tet) (66%), and trimethoprim-sulfamethoxazole (Sxt) (84%). Sixty-five percent of the isolates were multidrug resistant. Shigella flexneri isolates were more resistant than those of Shigella sonnei to Amp (66% versus 0.0%, P < 0.001) and Chl (61% versus 0.0%, P < 0.001), whereas S. sonnei isolates presented higher resistance to Tet than S. flexneri isolates (93% versus 64%, P ‫؍‬ 0.02). Resistance among Salmonella isolates was as follows: Tet and Chl, 15% each; Sxt, 18%; and Amp, 25%. Only 3% of Salmonella isolates were resistant to nalidixic acid (Nal), and none to ciprofloxacin or ceftriaxone (Cro). Among Salmonella isolates, multiresistance was found in 23%. Among Shigella isolates, antibiotic resistance was related mainly to the presence of oxa-1-like ␤-lactamases for Amp, dfrA1 genes for Sxt, tetB genes for Tet, and Chl acetyltransferase (CAT) activity for Chl. Among Salmonella isolates, resistance was conferred by tem-like ␤-lactamases for Amp, floR genes and CAT activity for Chl, tetA genes for Tet, and dfrA1 genes for Sxt. Our data show that Shigella isolates are resistant mostly to the most available, inexpensive antibiotics by various molecular mechanisms but remain susceptible to ciprofloxacin, Cro, and Nal, which is the first line for empirical treatment of shigellosis in the country.