TITLE:
Effect of Antibiotic Consumption on Resistance of Pseudomonas aeruginosa Isolated from Lebanese Patients with Emphasis on MBL Production
AUTHORS:
Rima Mouawad, Claude Afif, Eid Azar, Elias Dahdouh, Khalil Masri, Jihad Irani, Ziad Daoud
KEYWORDS:
Pseudomonas aeruginosa; MBL; Antibiotic Consumption; Bacterial Resistance
JOURNAL NAME:
Advances in Microbiology,
Vol.3 No.4,
August
6,
2013
ABSTRACT: The relationship between antibiotic
consumption and resistance has been widely evaluated. Pseudomonas aeruginosa is
one of the most important opportunistic pathogens in the nosocomial setting,
and its resistance to antibiotics is increaseing. Production of metallo-β-lactamases (MBLs) is currently the
most fearful resistance mechanism due to the potential of dissemination. This
study aimed to evaluate the correlation between antibiotic consumption (expressed
in DDD/100 bed days) and resistance (expressed in % of isolates and patients)
in different time periods for P. aeruginosa between 2006 and 2009 at Saint
George Hospital University Medical Center (SGH-UMC), Beirut. Pearson
correlation coefficients (r) were calculated and linear regression was
performed. Detection of MBL-producing Imipenem resistant P. aeruginosa (IRPA)
isolates between 2008 and 2009 was performed using three MBL screening methods:
MBL Etest?, Imipenem/EDTA combined disk test and EDTA disk potentiation with
four cephalosporins. The modified Hodge test was also performed. From 2006 till
2009, there was a trend of increasing resistance of P. aeruginosa to all
antibiotics, and the highest % of resistance was for Ofloxacin. Concerning
resistance expressed by isolates, high correlation coefficients resulted among Imipenem,
Ciprofloxacin and Tazobactam consumption and resistance to these agents in the
same year correlation; Ceftazidime and Ofloxacin consumption and resistance in
the next year correlation; Gentamicin and Ofloxacin consumption and the change
in resistance (ΔR). Concerning resistance expressed by patients, results were
similar except for Ceftazidime and Ofloxacin correlation in the next year
correlation. In MBL screening, three isolates gave accordance among 4
methods which showed a positive result. The correlation between antibiotic
consumption and resistance is highly dependent on the kind of antibiotic, the
organism and the time of correlation. Various MBL screening phenotypic methods
on one isolate can increase accuracy and eliminate false positive and negative
results.