Soltan Dallal Mm, Azarsa M, Shirazi Mh, Rastegar Lari A, Owlia P, Fallah Mehrabadi J, Sabbaghi A, Molla Aghamirzaei H, Shamkani F, Avadis Yans S, Mobasseri G, Bakhtiari R, Sharifi Yazdi Mk,
Volume 69, Issue 5 (8-2011)
Abstract
Background: Numerous use of Beta Lactame in treatment of bacterial infections resulted in increments of drug resistance of such bacteria. One of difficulties in treatment of hospital infections is Extended Spectrum Beta Lactamase (ESBL) among isolated clinical strains of E.coli. Since some of ESBL strains shows double reaction in drug sensitivity test at in vitro and in vivo condition, therefore it makes difficulties in selection of right treatment. In the last years, CTX-M enzymes have become the most prevalent ESBLs in worldwide. The prevalence of ESBL types largely remains unknown in many parts of the Iran. This study was made to find the prevalence of ESBL-producing E.coli and molecular detection of CTX-M-1 in Tabriz.
Methods: In the present study, 400 urine samples collected between November 2009 and April 2010, from Tabriz Hospitals were studied. Out of the 400 samples, 188 E.coli isolates were detected by standard biochemical tests. Susceptibility to antimicrobial agents was tested to 10 antibiotics by the disk agar diffusion (DAD) method. ESBL production was screened by phenotypic test that included both separate and combined disk agar diffusion techniques. The screened isolates were investigated by PCR assay to detect CTX-M-1 gene.
Results: From the total 188 E.coli isolates, 82 (43.6%) were shown to produce ESBLs by phenotypic test. During the PCR method on the 82 isolates, 69 (84.1%) were confirmed as CTX-M-1 producing group.
Conclusion: The present study showed that CTX-M-producing isolates were increasing among E.coli strains and indicated the need for adequate susceptibility tests in laboratories for choosing the appropriate antibiotics for treatment.
Rahbar Mohammad, Azimi Leila, Mohammad-Zadeh Monaaranak, Alinejad Faranak, Soleymanzadeh Somayeh, Sattarzadeh Mahboobeh, Rastegar Lari Abdolaziz,
Volume 70, Issue 3 (6-2012)
Abstract
Background: The increasing use of β-lactam antibiotics in clinics for the treatment of different bacterial infections since early 1980s has led to increased rates of resistant bacteria isolated from patients. One of the problems in the treatment of nosocomial infections is related to resistant bacteria such as Enterobacter cloacae due to cross resistance through extended-spectrum beta-lactamase production. The aim of this study was to determine the prevalence of extended-spectrum beta-lactamase producing E. cloacae from different clinical specimens collected from hospitalized patients.
Methods: In the present study, 101 E. cloacae confirmed by standard specific microbiologic tests were collected from different specimens in Milad and Motahri hospitals in Tehran, Iran during February 2010 and September 2011. Antibiotic susceptibility tests were conducted according to the process recommended by the Clinical and Laboratory Standards Institute for 13 antibiotics of choice. Extended-spectrum beta-lactamase producing strains were screened for by combined disk method as a phenotypic diagnostic test.
Results: From a total of 101 E. cloacae, 33 (33%) were shown to produce extended-spectrum beta-lactamase by phenotypic tests 5% of the bacteria were resistant to imipenem too.
Conclusion: This study clearly showed the high prevalence of resistance to broad-spectrum beta-lactam antibiotics in the isolated E. cloacae among which 5% were multi drug resistant. All the isolated E. cloacae were susceptible to Colistin. These results can be alarming for physicians treating resistant E. cloacae infections, especially extended-spectrum beta-lactamase producing species.
