Molecular Epidemiology and Clinical Impact of Acinetobacter calcoaceticus-baumannii Complex in a Belgian Burn Wound Center

Abstract

Multidrug resistant Acinetobacter baumannii and its closely related species A. pittii and A. nosocomialis, all members of the Acinetobacter calcoaceticus-baumannii (Acb) complex, are a major cause of hospital acquired infection. In the burn wound center of the Queen Astrid military hospital in Brussels, 48 patients were colonized or infected with Acb complex over a 52-month period. We report the molecular epidemiology of these organisms, their clinical impact and infection control measures taken. A representative set of 157 Acb complex isolates was analyzed using repetitive sequence-based PCR (rep-PCR) (DiversiLab) and a multiplex PCR targeting OXA-51-like and OXA-23-like genes. We identified 31 rep-PCR genotypes (strains). Representatives of each rep-type were identified to species by rpoB sequence analysis: 13 types to A. baumannii, 10 to A. pittii, and 3 to A. nosocomialis. It was assumed that isolates that belonged to the same rep-type also belonged to the same species. Thus, 83.4% of all isolates were identified to A. baumannii, 9.6% to A. pittii and 4.5% to A. nosocomialis. We observed 12 extensively drug resistant Acb strains (10 A. baumannii and 2 A. nosocomialis), all carbapenem-non-susceptible/colistin-susceptible and imported into the burn wound center through patients injured in North Africa. The two most prevalent rep-types 12 and 13 harbored an OXA-23-like gene. Multilocus sequence typing allocated them to clonal complex 1 corresponding to EU (international) clone I. Both strains caused consecutive outbreaks, interspersed with periods of apparent eradication. Patients infected with carbapenem resistant A. baumannii were successfully treated with colistin/rifampicin. Extensive infection control measures were required to eradicate the organisms. Acinetobacter infection and colonization was not associated with increased attributable mortality.

Predicting and managing sepsis in burn patients: current perspectives

“… 104 , 116 , 117 Colistin, an old antibiotic discontinued because of its nephrotoxicity, has re-emerged as an useful agent in the treatment of infections caused by MDRO. 118 , 119 However, due to the use of colistin, the appearance of colistin-resistant organisms is worrisome, as available therapeutic options seem scarce; some studies have reported the usefulness of combination therapy (eg, colistin, amikacin, tigecycline) in the treatment of colistin-resistant infections. 120 , 121 Early consultation of infectious diseases specialists is advocated in challenging cases.…”

Stability of bacteriophages in burn wound care products

“…Due to their capacity for long-term survival in the hospital environment, combined with a formidable inherent and acquired antibiotic resistance, some A . baumannii strains have emerged as important nosocomial pathogens, especially in critically ill patients, as found in intensive care units and burn wound centers [ 3 ]. Multidrug resistant strains of A .…”

Triclosan Alters Microbial Communities in Freshwater Microcosms

“…Although it is possible that the different Acinetobacter ASVs that were found in this study resulted from different 16S rRNA sequences being present in a single organism, Acinetobacter is not known to contain different 16S-or we would observe the same results at all concentrations where the genus is present. Such findings are especially important, since the genus is highly recombinogenic [35] and contains various antibiotic-resistant species pathogenic to humans or other organisms, even though we cannot confirm the pathogenicity of the bacterium while using current methodologies [44,45].…”