Wide distribution of carbapenem resistant Acinetobacter baumannii in burns patients in Iran

Abstract

Antimicrobial resistance in carbapenem non-susceptible Acinetobacter baumannii (CNSAb) is a major public health concern globally. This study determined the antibiotic resistance and molecular epidemiology of CNSAb isolates from a referral burn center in Tehran, Iran. Sixty-nine CNSAb isolates were tested for susceptibility to antimicrobial agents using the E test methodology. Multiple locus variable number tandem repeat analysis (MLVA), Multilocus sequence typing (MLST) and multiplex PCR were performed. PCR assays tested for ambler classes A, B, and D β-lactamases. Detection of ISAba1, characterization of integrons, and biofilm formation were investigated. Fifty-three (77%) isolates revealed XDR phenotypes. High prevalence of blaOXA-23-like (88%) and blaPER-1 (54%) were detected. ISAba1 was detected upstream of blaADC, blaOXA-23-like and blaOXA51-like genes in, 97, 42, and 26% of isolates, respectively. Thirty-one (45%) isolates were assigned to international clone (IC) variants. MLVA identified 56 distinct types with six clusters and 53 singleton genotypes. Forty previously known MLST sequence types forming 5 clonal complexes were identified. The Class 1 integron (class 1 integrons) gene was identified in 84% of the isolates. The most prevalent (33%) cassette combination was aacA4-catB8-aadA1. The IC variants were predominant in the A. baumannii lineage with the ability to form strong biofilms. The XDR-CNSAb from burned patients in Iran is resistant to various antimicrobials, including tigecycline. This study shows wide genetic diversity in CNSAb. Integrating the new Iranian A. baumannii IC variants into the epidemiologic clonal and susceptibility profile databases can help effective global control measures against the XDR-CNSAb pandemic.

Significant spread of extensively drug-resistant Acinetobacter baumannii genotypes of clonal complex 92 among intensive care unit patients in a university hospital in southern Iran

“…The high degree of mobility that characterizes the class 1 integrons is illustrated by our finding that indistinguishable PFGE types varied in their integron content. In short, we found a high prevalence of class I integrons and low prevalence of class 2 integrons in XDR phenotypes, which agrees with data obtained in other investigations [6,28,35].…”

“…Our findings showed a high prevalence of A. baumannii isolates that were XRD, which agrees with other investigations conducted in Iran [14,28]. Resistance to carbapenems was common, and indeed 92 % of the isolates were resistant to all three of the tested carbapenems.…”

“…CC92 is highly prevalent throughout Asia, and it is the CC with the widest global distribution [11]. Overall, our findings corroborate previous surveys conducted in Europe, where the majority of outbreaks have been associated with CRAB producing oxacillinase OXA-23 and belonging to ICL2 [12] Similarly, in a recent study performed at a referral burns centre in Tehran, the majority of CRAB isolates assessed belonged to CC92 and carried class I integrons and OXA-23-like carbapenemase [16]. The most prevalent STs in the present investigation (ST848, ST451, ST195) have not been observed in previous studies at Iranian hospitals [28], whereas other STs belonging to CC92 (e.g.…”

“…Such information is also essential to enable infection control professionals to develop and balance control strategies aimed at reducing the spread and disease burden of multidrug-resistant (MDR) A. baumannii in the hospital setting. Several valuable techniques have been utilized and have contributed to our understanding of the genotypic characterization of A. baumannii isolates in the healthcare setting: PFGE [9,12,13], multilocus sequence typing (MLST) [12,14,15] and multilocus variable-number tandem-repeat (VNTR) analysis (MLVA) [13,16].…”

“…According to studies conducted in several European countries, the majority of CRAB outbreaks in that region have been associated with ICL2 isolates harbouring the oxacillinase bla OXA-23 -like carbapenemase gene [2,12]. Epidemiological investigations have described dissemination of A. baumannii isolates belonging to clonal complex 92 (CC92), corresponding to ICL2, in two hospitals in northern Iran [14,16]. However, there is no available information indicating such spread in the hospital setting in southern Iran (i.e.…”