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Detection of AmpC-β-lactamases producing isolates among carbapenem resistant P. aeruginosa isolated from burn patient.

Mirsalehian A, Kalantar-Neyestanaki D, Nourijelyani K, Asadollahi K, Taherikalani M, Emaneini M, Jabalameli F - Iran J Microbiol (2014)

Bottom Line: One isolate was identified as AmpC producer using three methods.Three isolates produced AmpC as detected by both AmpC disk test and combined disk methods and 19 isolates were found as AmpC producer using both AmpC disk test and minimum inhibitory concentration methods.According to the results of this study, AmpC- β-lactamase looks to be the main mechanism of resistance of Pseudomonas aeruginosa to cephalosporins and carbapenems in the study hospital.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbiology, School of Medicine, Tehran University of Medical Sciences. Tehran, Iran.

ABSTRACT

Background and objectives: Pseudomonas aeruginosa is responsible for devastating nosocomial infections among severely burn patients. Class C of cephalosporinase (AmpC-β-lactamases) is important cause of multiple β-lactam resistance in P. aeruginosa. The aim of this study was to detect the AmpC-β-lactamases producing isolates among carbapenem resistant P. aeruginosa isolated from burn patient.

Material and methods: a total of 100 isolates of carbapenem resistant P. aeruginosa isolates from different burn patients were investigated. Three phenotypic methods were selected for identification of the AmpC-β-lactamases producing isolates.

Results: Fifty four isolates were AmpC producer as detected by AmpC disk test. Seventeen isolates were identified as AmpC producer using combined disk method. Fifty two isolates showed a twofold or threefold dilution difference between the minimum inhibitory concentration of imipenem or ceftazidime and the minimum inhibitory concentration of imipenem or ceftazidime plus cloxacillin. One isolate was identified as AmpC producer using three methods. Three isolates produced AmpC as detected by both AmpC disk test and combined disk methods and 19 isolates were found as AmpC producer using both AmpC disk test and minimum inhibitory concentration methods. Six isolates were AmpC producer as shown by the MICs of both imipenem and ceftazidime.

Conclusion: According to the results of this study, AmpC- β-lactamase looks to be the main mechanism of resistance of Pseudomonas aeruginosa to cephalosporins and carbapenems in the study hospital.

No MeSH data available.


Related in: MedlinePlus

AmpC-β-lactamase producing isolate:A;Cefepime,B; Cefepime + Phenylboronic acid(BA),C; Ceftazidime,D; Ceftazidime + BA.
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Figure 2: AmpC-β-lactamase producing isolate:A;Cefepime,B; Cefepime + Phenylboronic acid(BA),C; Ceftazidime,D; Ceftazidime + BA.

Mentions: During the study, a total of 100 clinical isolates of P. aeruginosa resistance to carbapenems (imipenem, meropenem or ertapenem) were collected from different burn patients who were admitted at Shahid Motahari Hospital of Tehran University of Medical Sciences. Susceptibility results and MICs are shown in Table 1. Seventy carbapenem-resistant P. aeruginosa with MICs ≥32μg/ml for IMI were isolated from different patients. The MICs of CAZ against 70 isolates were ≥ 1024 μg/ml. Fifty two isolates showed a twofold or threefold dilution difference between the MICs of IMI or CAZ and the MICs of IMI or CAZ plus COL. MICs to imipenem and ceftazidime in AmpC overproduction isolates of P. aeruginosa with/without cloxacillin are shown in Table 2. The prevalence of AmpC-β-lactamases producers by three phenotypic methods is shown in Table 3. Fifty four isolates were recognized as AmpC producers in AmpC disk test (Fig. 1). Seventeen isolates showed AmpC-β-lactamases activity in combined disk method (Fig. 2). One isolate was identified as AmpC-β-lactamases producer using three methods. Three isolates were AmpC producer as shown by both AmpC disk test and combined disk methods and 19 isolates demostrated AmpC activity by both AmpC disk test and MIC methods. Six isolates were proved to be AmpC producer as determined by MICs of IMI and CAZ.


Detection of AmpC-β-lactamases producing isolates among carbapenem resistant P. aeruginosa isolated from burn patient.

Mirsalehian A, Kalantar-Neyestanaki D, Nourijelyani K, Asadollahi K, Taherikalani M, Emaneini M, Jabalameli F - Iran J Microbiol (2014)

AmpC-β-lactamase producing isolate:A;Cefepime,B; Cefepime + Phenylboronic acid(BA),C; Ceftazidime,D; Ceftazidime + BA.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4385569&req=5

Figure 2: AmpC-β-lactamase producing isolate:A;Cefepime,B; Cefepime + Phenylboronic acid(BA),C; Ceftazidime,D; Ceftazidime + BA.
Mentions: During the study, a total of 100 clinical isolates of P. aeruginosa resistance to carbapenems (imipenem, meropenem or ertapenem) were collected from different burn patients who were admitted at Shahid Motahari Hospital of Tehran University of Medical Sciences. Susceptibility results and MICs are shown in Table 1. Seventy carbapenem-resistant P. aeruginosa with MICs ≥32μg/ml for IMI were isolated from different patients. The MICs of CAZ against 70 isolates were ≥ 1024 μg/ml. Fifty two isolates showed a twofold or threefold dilution difference between the MICs of IMI or CAZ and the MICs of IMI or CAZ plus COL. MICs to imipenem and ceftazidime in AmpC overproduction isolates of P. aeruginosa with/without cloxacillin are shown in Table 2. The prevalence of AmpC-β-lactamases producers by three phenotypic methods is shown in Table 3. Fifty four isolates were recognized as AmpC producers in AmpC disk test (Fig. 1). Seventeen isolates showed AmpC-β-lactamases activity in combined disk method (Fig. 2). One isolate was identified as AmpC-β-lactamases producer using three methods. Three isolates were AmpC producer as shown by both AmpC disk test and combined disk methods and 19 isolates demostrated AmpC activity by both AmpC disk test and MIC methods. Six isolates were proved to be AmpC producer as determined by MICs of IMI and CAZ.

Bottom Line: One isolate was identified as AmpC producer using three methods.Three isolates produced AmpC as detected by both AmpC disk test and combined disk methods and 19 isolates were found as AmpC producer using both AmpC disk test and minimum inhibitory concentration methods.According to the results of this study, AmpC- β-lactamase looks to be the main mechanism of resistance of Pseudomonas aeruginosa to cephalosporins and carbapenems in the study hospital.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbiology, School of Medicine, Tehran University of Medical Sciences. Tehran, Iran.

ABSTRACT

Background and objectives: Pseudomonas aeruginosa is responsible for devastating nosocomial infections among severely burn patients. Class C of cephalosporinase (AmpC-β-lactamases) is important cause of multiple β-lactam resistance in P. aeruginosa. The aim of this study was to detect the AmpC-β-lactamases producing isolates among carbapenem resistant P. aeruginosa isolated from burn patient.

Material and methods: a total of 100 isolates of carbapenem resistant P. aeruginosa isolates from different burn patients were investigated. Three phenotypic methods were selected for identification of the AmpC-β-lactamases producing isolates.

Results: Fifty four isolates were AmpC producer as detected by AmpC disk test. Seventeen isolates were identified as AmpC producer using combined disk method. Fifty two isolates showed a twofold or threefold dilution difference between the minimum inhibitory concentration of imipenem or ceftazidime and the minimum inhibitory concentration of imipenem or ceftazidime plus cloxacillin. One isolate was identified as AmpC producer using three methods. Three isolates produced AmpC as detected by both AmpC disk test and combined disk methods and 19 isolates were found as AmpC producer using both AmpC disk test and minimum inhibitory concentration methods. Six isolates were AmpC producer as shown by the MICs of both imipenem and ceftazidime.

Conclusion: According to the results of this study, AmpC- β-lactamase looks to be the main mechanism of resistance of Pseudomonas aeruginosa to cephalosporins and carbapenems in the study hospital.

No MeSH data available.


Related in: MedlinePlus