Antimicrobial agents and chemotherapy
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Antimicrob. Agents Chemother. · Oct 2014
Antibiotic pressure is a major risk factor for rectal colonization by multidrug-resistant Pseudomonas aeruginosa in critically ill patients.
The intestinal reservoir is central to the epidemiology of Pseudomonas aeruginosa, but the dynamics of intestinal colonization by different phenotypes have been poorly described. To determine the impact of antimicrobial exposure on intestinal colonization by multidrug-resistant (MDR) and extensively drug-resistant (XDR) P. aeruginosa, we screened intensive care unit (ICU) patients for rectal colonization on admission and at weekly intervals. During an 18-month study period, 414 ICU patients were enrolled, of whom 179 (43%) were colonized; 112 (63%) of these were identified at ICU admission and 67 (37%) during their ICU stay. ⋯ The Cox regression analysis identified MDR P. aeruginosa acquisition as associated with the underlying disease severity (adjusted hazard ratio [aHR], 1.97; 95% confidence interval [CI], 1.22 to 3.18; P = 0.006) and prior use of fluoroquinolones (aHR, 1.02; 95% CI, 1.00 to 1.04; P = 0.039), group 2 carbapenems (aHR, 1.03; 95% CI, 1.00 to 1.07; P = 0.041), and ertapenem (aHR, 1.08; 95% CI, 1.02 to 1.14; P = 0.004). The epidemiology of MDR P. aeruginosa is complex, and different clusters may coexist. Interestingly, ertapenem was found to be associated with the emergence of MDR isolates.
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Antimicrob. Agents Chemother. · Oct 2014
In vivo effect of quaternized chitosan-loaded polymethylmethacrylate bone cement on methicillin-resistant Staphylococcus epidermidis infection of the tibial metaphysis in a rabbit model.
Infection of open tibial fractures with contamination remains a challenge for orthopedic surgeons. Local use of antibiotic-impregnated polymethylmethacrylate (PMMA) beads and blocks is a widely used procedure to reduce the risk of infection. However, the development of antibiotic-resistant organisms make the management of infection more difficult. ⋯ The radiographic scores and gross bone pathological and histopathological scores were significantly lower in the PMMA-H group than in the PMMA, PMMA-G, and PMMA-C groups (P < 0.05). Explant cultures also indicated significantly less bacterial growth in the PMMA-H group than in the PMMA, PMMA-G, and PMMA-C groups (P < 0.01). We concluded that PMMA-H bone cement can inhibit the development of bone infections in this animal model inoculated with antibiotic-resistant bacteria, thereby demonstrating its potential application for treatment of local infections in open fractures.
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Antimicrob. Agents Chemother. · Sep 2014
Epidemiology and predictors of multidrug-resistant community-acquired and health care-associated pneumonia.
There are limited U. S. data describing the risk factors for multidrug-resistant organism (MDRO) isolation in community-acquired pneumonia (CAP) and health care-associated pneumonia (HCAP). However, concern for the presence of these pathogens drives the prescribing of empiric broad-spectrum antibiotics for CAP and HCAP. ⋯ MDROs were uncommon in HCAP and CAP. HCAP did not predict MDRO isolation. Local etiology of community onset pneumonia and specific MDRO risk factors should be integrated into therapeutic decisions to prevent empirical overprescribing of antibiotics for methicillin-resistant Staphylococcus aureus (MRSA) and P. aeruginosa.
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Antimicrob. Agents Chemother. · Sep 2014
First detection of TR46/Y121F/T289A and TR34/L98H alterations in Aspergillus fumigatus isolates from azole-naive patients in Denmark despite negative findings in the environment.
Azole-resistant Aspergillus fumigatus harboring the TR34/L98H or TR46/Y121F/T289A alterations is increasingly found in Europe and Asia. Here, we present the first clinical cases of TR46/Y121/T289A and three cases of TR34/L98H outside the cystic fibrosis (CF) population in Denmark and the results of environmental surveys. Four patients (2012 to 2014) with 11 A. fumigatus and 4 Rhizomucor pusillus isolates and 239 soil samples (spring 2010 and autumn 2013, respectively) with a total of 113 A. fumigatus isolates were examined. ⋯ TR34/L98H and TR46/Y121F/T289A alterations appear to be emerging in the clinical setting in Denmark and now involve azole-naive patients. Two recent soil-sampling surveys in Denmark were unable to indicate any increased prevalence of azole-resistant A. fumigatus in the environment. These findings further support the demand for real-time susceptibility testing of all clinically relevant isolates and for studies investigating the seasonal variation and ecological niches for azole-resistant environmental A. fumigatus.
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Antimicrob. Agents Chemother. · Sep 2014
Efficacy of fosfomycin compared to vancomycin in treatment of implant-associated chronic methicillin-resistant Staphylococcus aureus osteomyelitis in rats.
Fosfomycin monotherapy was compared to therapy with vancomycin for the treatment of implant-associated methicillin-resistant Staphylococcus aureus (MRSA) osteomyelitis in an experimental rat model. The proximal tibiae were inoculated with 15 μl of a suspension containing 1×10(8) to 5×10(8) CFU/ml of a clinical isolate of MRSA with simultaneous insertion of a titanium wire. Four weeks later, treatment was started for 28 days with either 50 mg/kg of body weight vancomycin intraperitoneally twice daily (n=11) or 75 mg/kg fosfomycin intraperitoneally once daily (n=10). ⋯ Based on the bacterial counts from the implants, vancomycin was not superior to the no-drug control (P=0.324), and fosfomycin was superior to the no-drug control and vancomycin (P<0.001). No emergence of resistance was observed. In conclusion, it was demonstrated that fosfomycin monotherapy is highly effective for the treatment of experimental implant-associated MRSA osteomyelitis.