Dissemination and Genetic Relatedness of Multidrug-Resistant and Extensively Drug-Resistant Acinetobacter baumannii Isolates from a Burn Hospital in Iraq

Abstract

Acinetobacter baumannii is an aggressive opportunistic bacterial pathogen that causes severe nosocomial infections, especially among burn patients. An increasing number of hospitals-acquired infections have been reported all over the world. However, little attention has been paid to the relatedness between A. baumannii isolates from different hospital environments and patients. In this study, 27 isolates were collected from the Burn and Plastic Surgery Hospital of Al Sulaymaniyah City, Iraq, from January through December 2019 (11 from patients and 16 from the wards environment), identified to species level as A. baumannii using Vitek 2 system and molecular detection of 16S rRNA gene, and then confirmed by targeting the blaOXA-51 gene. Moreover, the isolates were characterized by means of automated antimicrobial susceptibility assay, antimicrobial-resistant patterns, a phenotypic method using a combined disk test, and molecular methods for the detection of class A and C β -lactamase genes, and finally, the genetic relatedness was classified. Antimicrobial susceptibility testing showed that 63% (17/27) of the retrieved A. baumannii isolates were extensively drug-resistant to 8/9 antimicrobial classes. Furthermore, 37% (10/27) of the isolates were classified as multidrug-resistant; 8 isolates exhibited similar resistant patterns and the other two isolates showed 2 different patterns, while resistance was greater in isolates from patients than from the ward environment. Combined disk test showed that two isolates contained extended-spectrum β -lactamase. All isolates carried blaTEM-1, and two copies of the blaCTX-1 gene were indicated in one isolate, while blaSHV was absent in all isolates. Twenty-four isolates carried the blaAmpC gene; among them, 3 isolates harbored the insertion sequence ISAba-1 upstream to the gene. Using Enterobacterial Repetitive Intergenic Consensus PCR, the isolates were clustered into 6 distinct types; among them, two clusters, each of four strains, were classified to contain isolates from both patients and environments. The clusters of similar genotypes were found in inpatients as well as the environments of different wards during time periods, suggesting transmission within the hospital. Identification of possible infection sources and controlling the transmission of these aggressive resistance strains should be strictly conducted.

Molecular Detection of Plasmid-Mediated AmpC in Gram Negative Bacteria Isolated from Intensive Care Unit Patients in Wasit Province, Iraq

“…It was reported in another study by Milton et al (21) . Result AmpC β-lactamases in the current study was cefoxitin (100%) of Acinetobacter baumannii are similar with the study performed by Shali et al (22) which was the result (100%).…”

Carbapenem Resistance Mechanisms in Acinetobacter baumannii: Spotlight on OXA Genes

“…Ceftazidime displayed a resistance rate of 88.1%, which was consistent with the findings of [13,23,27]. Cefepime exhibited a resistance rate of 100%, similar to [27], but differing from [24,28]. Cefotaxime demonstrated a resistance rate of 98.3%, consistent with [13,25,27], but differing from [24].…”

“…Resistance rates for beta-lactam combinations varied as well. Ampicillinsulbactam exhibited a resistance rate of 57.6%, contradicting the findings of [23] but closely resembled the result of [24]. For pipracillin-tazobactam, the resistance rate was 93.2%, which was consistent with the findings of [23].…”

“…These resistance patterns are consistent with previous studies [21][22][23]reporting similar findings for ampicillin. However, there were discrepancies in the resistance rates for pipracillin compared to studies conducted by [21,[24][25][26]. Resistance rates for beta-lactam combinations varied as well.…”

Phenotypic and Genotypic Investigation of Carbapenem-Resistant Acinetobacter baumannii in Maharaj Nakhon Si Thammarat Hospital, Thailand

“…The stained dye of the adhering cells was dissolved with absolute ethanol. The solution’s optical density was measured at 580 nm [ 63 ]. This absorbance value of the solution indicated the biofilm-forming capacity of the isolate.…”