Stable carbapenem susceptibility rates among multidrug-resistant Acinetobacter spp. strains in a setting of high prevalence of carbapenem-resistant Pseudomonas aeruginosa

Zavascki, Alexandre Prehn; Soares, Fabiana; Superti, Silvana; Silbert, Suzane; Silva, Fernanda M.; Barth, Afonso Luís

doi:10.1016/j.ijantimicag.2007.03.001

Cited by 6 publications

(4 citation statements)

References 7 publications

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“…The proportion of carbapenem resistance in Acinetobacter spp. from the ICU increased from 29 Table 3. Mortality rates of the 24 patients who received appropriate therapy compared to the 42 who did not receive appropriate therapy are shown in Figure 1.…”

Section: Resultsmentioning

confidence: 98%

“…Another limitation of our study, which did not affect our main findings, is that not all isolates had their genetic basis of resistance determined and not all were submitted to molecular typing. The outbreak in the institution of this study occurred in parallel with a large city-wide outbreak after a long period of stable carbapenem susceptibility rates [26, 29], and although the great majority of the isolates recovered from distinct institutions of our city were also OXA-23 producers, in a few isolates no carbapenemase was detected [26]. Thus, it is possible that another resistance mechanism might be responsible for the carbapenem-resistant phenotype of the remaining isolates, considering the characteristic of the isolates recovered from other institutions in our city.…”

Section: Discussionmentioning

confidence: 99%

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Risk factors for 30-day mortality in patients with carbapenem-resistantAcinetobacter baumanniiduring an outbreak in an intensive care unit

et al. 2010

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This study assessed risk factors for 30-day mortality in 66 patients with carbapenem-resistant Acinetobacter baumannii (CRAB) infection or colonization during an outbreak in an intensive-care unit. Clinical and demographic characteristics were evaluated. The overall 30-day mortality was 47·0%. In the multivariate Cox regression model, septic shock [adjusted hazard ratio (aHR) 5·01, 95% confidence interval (CI) 2·32-10·01] and APACHE II score at onset of infection (aHR 1·11, 95% CI 1·04-1·18) were significantly associated with 30-day mortality. Administration of appropriate therapy was a protective factor, but it was not statistically significant (aHR 0·48, 95% CI 0·21-1·12). A sample of isolates tested (n=27) carried the blaOXA-23 gene. Severity of baseline condition and severity of infection presentation were major risk factors for mortality during the outbreak. Patients who received appropriate therapy tended to have lower mortality rates, although therapy was started late and dosage was suboptimal in most cases.

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Section: Resultsmentioning

confidence: 98%

Section: Discussionmentioning

confidence: 99%

Risk factors for 30-day mortality in patients with carbapenem-resistantAcinetobacter baumanniiduring an outbreak in an intensive care unit

et al. 2010

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“…In March 2006, a first A. baumannii resistant to both imipenem and meropenem was identified in our institution 12 . Two isolates were recovered from an intra-abdominal abscess secretion and from the blood of a 67-year-old female patient at ICU, respectively.…”

Section: Case Reportmentioning

confidence: 99%

Indications of carbapenem resistance evolution through heteroresistance as an intermediate stage in Acinetobacter baumannii after carbapenem administration

Superti

Martins

Caierão

et al. 2009

Rev. Inst. Med. trop. S. Paulo

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SUMMARYWe describe an in vivo evolution of an antimicrobial profile from susceptibility to full-resistance to carbapenems, with heteroresistance as an intermediate stage, in an Acinetobacter baumannii strain. Heteroresistance was characterized by the growth of sub-populations within the susceptibility halo in both disk-diffusion and Etest. PCRs for the main A. baumannii carbapenemases were negative. The exact resistance mechanism, diagnostic methods and clinical relevance of heteroresistance in A. baumannii warrant further investigations. This is the first description of such phenomenon in vivo and the second report of heteroresistance to carbapenems in A. baumannii.

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“…has been found at the fourth rank in hospitalized patients with pneumonia in Latin America [6] and at the second one in patients with nosocomial pneumonia in Argentina [7], with carbapenem resistance increasing dramatically [4], especially in Argentina [4,7] and in Colombia [4,8]. This kind of resistance has also been reported at modest rates in Chile [4] and Brazil [4,9], albeit it seems to remain stable in some regions of this late country [10]. As a result, old antibiotics, such as colistin and ampicillinsulbactam, have emerged as the obligate alternative for treating serious infections associated with A. baumannii [11].…”

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confidence: 97%

Pharmacodynamic assessment of Amoxicillin-Sulbactam against Acinetobacter baumannii: searching the optimal dose and infusion time through a human ex-vivo model

Bantar¹,

Canigia²,

Berger³

et al. 2009

Braz J Infect Dis

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Amoxicillin-sulbactam (AMX-SUL) is an aminopenicillin/ß-lactamase inhibitor combination currently available in 29 countries and may be a suitable option for treating infections caused by Acinetobacter spp. Thus, we sought to search the optimal dosing strategy for this formulation through an ex vivo pharmacodynamic human model against Acinetobacter baumanniii. Four volunteers were randomized to receive alternatively a single dose AMX-SUL infused both either over 30 min or 3h at the following ratios (g/g): 1/0.5; 1/1, and 0/2. Time-kill studies were performed with the 0-, 0.5-, 2-, 4-, 6-and 8-h sera after dose against a clinical isolate of A. baumannii (sulbactam MIC, 4µg/mL). Bactericidal activity (i.e. a mean decrease ≥3 log 10 CFU/mL in the viable cell counts from the initial inoculum) was displayed by the 0.5-and the 2-h sera after dose for all formulations. The 4-h sera proved inhibitory with the AMX-SUL 1g/1g formulation, albeit a trend to regrowth was observed after 24-h incubation. With the AMX-SUL 0g/2g dose, the 4-h sera proved almost bactericidal activity (i.e. a mean decrease of 2.4 log 10 CFU/mL in the viable cell counts from the initial inoculum), whereas the 6-h sera was inhibitory, with a trend to regrowth after 24-h incubation. When infused over 3h, AMX-SUL 1g/0.5g and 1g/1g, bactericidal activity was displayed by the 0.5-, 2-and the 4-h sera after dose and the 6-h sera proved inhibitory with the AMX-SUL 1g/1g formulation. The present study, albeit preliminary, might give a rationale for the dosing strategy to treat infections caused by A. baumannii with sulbactam, either alone or combined with amoxicillin. A 2-g sulbactam dose seems to be optimal to be infused over 30 min with a 6-h dosing interval. When infused over 3h, AMX-SUL 1g/1g given every 6h or 8h seems a suitable dosing schedule.

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Stable carbapenem susceptibility rates among multidrug-resistant Acinetobacter spp. strains in a setting of high prevalence of carbapenem-resistant Pseudomonas aeruginosa

Cited by 6 publications

References 7 publications

Risk factors for 30-day mortality in patients with carbapenem-resistantAcinetobacter baumanniiduring an outbreak in an intensive care unit

Risk factors for 30-day mortality in patients with carbapenem-resistantAcinetobacter baumanniiduring an outbreak in an intensive care unit

Indications of carbapenem resistance evolution through heteroresistance as an intermediate stage in Acinetobacter baumannii after carbapenem administration

Pharmacodynamic assessment of Amoxicillin-Sulbactam against Acinetobacter baumannii: searching the optimal dose and infusion time through a human ex-vivo model

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