Isolation and identification of acinetobacter baumannii clinical isolates using novel methods

Abstract EN

Acinetobacter baumannii has emerged over the last decade as a significant opportunistic pathogen.

Although it is generally associated with benign colonization of hospitalized patients.

The purpose of this study was undertaken to isolate and identify of A.

baumannii from clinical infections using different laboratory methods.

A total of 520 clinical samples (wound pus, urine, respiratory secretion, blood) were collected from February to June, 2011.

A.

baumannii isolates were preliminary identified according to the morphological characteristics and traditional biochemical test.

Then confirmed by using API 20E and API 20 NE multi-test system.

Isolates were further identified on molecular level using 16S rRNA specific gene by polymerase chain reaction (PCR).

All PCR positive isolates were examined to grow on CHROMagar Acinetobacter / MDR medium and their antibiotics susceptibility.

A total of 335 Gram negative bacilli isolates were obtained according to the morphological characteristics and traditional biochemical test.

Only 23(6.8 %) were identified as suspected A.

baumannii.

Ten (43.4 %) isolates revealed very good identification level by API 20E system.

While, API 20 multi-test system for non enteric bacteria identified only 12(52.1 %) isolates belonged to A.

baumannii.

The same isolates harbored positive bands in PCR experiments with specific primers for16S rRNA gene.

A.

baumannii isolates were distributed as 6(50 %) recovered from urine, 4(33.3 %) from lower respiratory secretion and only two (25 %) were obtained from wound pus, no A.

baumannii isolates were isolated from blood samples in this study.

Hence, 6 (50 %) of isolates were gave overnight pure growth on CHROMagar Acinetobacter / MDR medium with resistant to representatives of three or more classes of antibiotics.

The present findings suggest that the PCR using16S rRNA gene CHROMagar were gold standard method for detection of multi-drug resistant A.

baumannii isolates among patients in Najaf hospitals.