Archive for January 10, 2017

Are laboratory-based antibiograms reliable to guide the selection of empirical antimicrobial treatment in patients with hospital-acquired infections?

J Antimicrob Chemother. 2007 Jan;59(1):140-3. Epub 2006 Oct 31.

Bantar C1, Alcazar G, Franco D, Salamone F, Vesco E, Stieben T, Obaid F, Fiorillo A, Izaguirre M, Oliva ME.

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1Department of Infection Control, Hospital San Martín, Perón 450 (3100) Paraná, Entre Ríos, Argentina.



Antibiograms are often taken into account to define a rational selection of an empirical antimicrobial therapy for treating patients with hospital-acquired infections. In this study, we performed a paired comparison between the antibiogram constructed with laboratory-based data and that formed with data subjected to prior clinical validation.


Between 2003 and 2005, the laboratory of microbiology printed in duplicate every individual susceptibility report corresponding to hospitalized patients and the copy was sent to the department of infection control. Every individual report was assessed in real time at the bedside of the patient by a multidisciplinary team for clinical significance and appropriateness of the specimen, as well as for the type, source and origin of the infection. Cumulative resistance rates were estimated in parallel at the laboratory with the whole data, and at the infection control department with data subjected to prior clinical validation. These rates were designated as ‘laboratory-based’ and ‘clinically based’, respectively.


A total of 2305 individual susceptibility reports were assessed. Only 1429 (62.0%) were considered as clinically significant by the multidisciplinary team. Escherichia coli, Enterobacter cloacae, Citrobacter freundii group, Klebsiella species and Proteus mirabilis resistant to broad-spectrum cephalosporins, as well as methicillin-resistant Staphylococcus aureus, were significantly more frequent in the clinically based rates (P < or = 0.03).


Laboratory-based data underestimate the frequency of several major resistant organisms in patients with hospital-acquired infection. Previous clinical validation of the individual susceptibility reports seems to be a suitable strategy to get more reliable data.



January 10, 2017 at 8:51 am

Does a reduction in antibiotic consumption always represent a favorable outcome from an intervention program on prescribing practice?

Int J Infect Dis. 2006 May;10(3):231-5. Epub 2006 Feb 9.

Bantar C1, Franco D, Heft C, Vesco E, Arango C, Izaguirre M, Oliva ME.

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1Services of Infection Control, Hospital San Martín, Paraná, Entre Ríos, Argentina.



In our hospital, a continuous intervention program aimed at optimizing the quality of antibiotic use was introduced by late 1999 and antibiotic consumption was a major outcome for assessment.

However, healthcare conditions have been subject to change over the last five years, and a pronounced economic crisis in 2002 affected the availability of antibiotics.

Therefore, we hypothesized that the consumption of these drugs could be a suitable indirect marker of the crisis.


We performed segmented regression analysis between different periods. Variations in antibiotic consumption during periods corresponding to the four-phase intervention program (from 1999 to the first six months of 2001) were assumed to be ‘intervention-induced’, while those observed during the crisis period were considered as ‘situation-enforced’.


Whereas the intervention-induced (desirable) decrease of total antibiotic and carbapenem consumption proved to correlate with a decreased crude mortality rate during the control period prior to the crisis (R2, 0.82 and 0.91, respectively), the crisis-induced (undesirable) decrease in total antibiotic and carbapenem consumption correlated with an increased mortality during this phase (R2, 0.80 and 0.75, respectively).


Our results illustrate that a reduction in antibiotic consumption does not always represent a favorable outcome from an intervention program on prescribing practice. Moreover, it may be a sensitive indirect marker of a deficient healthcare condition leading to an increase in in-hospital mortality.


January 10, 2017 at 8:50 am

Replacement of broad-spectrum cephalosporins by piperacillin-tazobactam: impact on sustained high rates of bacterial resistance.

Antimicrob Agents Chemother. 2004 Feb;48(2):392-5.

Bantar C1, Vesco E, Heft C, Salamone F, Krayeski M, Gomez H, Coassolo MA, Fiorillo A, Franco D, Arango C, Duret F, Oliva ME.

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1Committee for Prevention and Control of Nosocomial Infection, Hospital San Martín, Paraná, Entre Ríos, Argentina.


We have previously observed a significant reduction of ceftriaxone resistance in Proteus mirabilis associated with an increase in the use of cefepime, along with a decrease in the consumption of broad-spectrum cephalosporins (CEP).

However, we did not observe such a reduction with Klebsiella pneumoniae. Therefore, we sought to determine whether replacement of CEP by piperacillin-tazobactam might be useful in reducing sustained high rates of CEP resistance by this organism.

We used a 6-month “before and after model”; during the second (intervention) period, most prescriptions of CEP were changed to piperacillin-tazobactam at the pharmacy. No additional barrier precautions were undertaken.

During intervention, consumption of ceftazidime decreased from 17.73 to 1.14 defined daily doses (DDD) per 1,000 patient-days (P < 0.0001), whereas that of piperacillin-tazobactam increased from 0 to 30.57 DDD per 1,000 patient-days (P < 0.0001).

The levels of resistance to CEP by K. pneumoniae and P. mirabilis decreased from 68.4 and 57.9% to 37.5 and 29.4%, respectively (P < 0.05).

We conclude that replacement of ceftazidime by piperacillin-tazobactam might be a suitable strategy to decrease endemic CEP resistance by K. pneumoniae and P. mirabilis, even where there are high bacterial resistance rates and irrespective of any additional precautions for controlling nosocomial infection.


January 10, 2017 at 8:48 am


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