Clonal Transmission of Gram-Negative Bacteria with Carbapenemases NDM-1, VIM-1, and OXA-23/72 in a Bulgarian Hospital

Abstract

We characterized 72 isolates with reduced susceptibility to carbapenems (50 Acinetobacter spp., 13 Proteus mirabilis, five Escherichia coli, one Morganella morganii, one Enterobacter cloacae, one Providencia rettgeri, and one Pseudomonas aeruginosa) from a hospital in Sofia, Bulgaria. Different β-lactamase genes were identified by polymerase chain reaction and sequencing. Bacterial strain typing was performed by enzymatic macrorestriction and pulsed-field gel electrophoresis (PFGE) typing as well as multilocus sequence typing for selected isolates. The majority of Acinetobacter baumannii (46/50) and one Acinetobacter pittii isolate harbored carbapenemase genes bla or bla; two A. baumannii contained both genes. PFGE typing of all A. baumannii showed the presence of nine different clones belonging to eight sequence types ST350, ST208, ST436, ST437, ST449, ST231, ST502, and ST579. Molecular characterization of the remaining isolates confirmed the presence of one NDM-1-producing E. coli-ST101 clone (five isolates) and one P. mirabilis clone (13 isolates) with VIM-1 and CMY-99. Furthermore, NDM-1 was identified in P. rettgeri and M. morganii and VIM-2 in the P. aeruginosa isolate. The permanent introduction of OXA-23/72 carbapenemase-producing A. baumannii clones into the hospital and the repeated occurrence of one VIM-1-producing P. mirabilis and one NDM-1-producing E. coli-ST101 clone over a period of more than 1 year is of concern and requires intensified investigations.

Clonal relatedness and resistance characteristics of OXA‐24 and ‐58 producing carbapenem‐resistantAcinetobacter baumanniiisolates in Tehran, Iran

“…While carbapenems have the most extended spectrum of antibacterial activity of all the beta‐lactams, the carbapenem resistance rate in A. baumannii has reached more than 50% worldwide in the past decade as reported in previous studies (Chagas et al ; Wang et al ; Ning et al ; Pfeifer et al ; Rieber et al ). Overall, CRAB isolates are resistant to multiple drugs which forcefully contribute to further outbreaks due to the limited treatment alternatives (Migliavacca et al ; Ning et al ; Rieber et al ).…”

“…Due to poor supervision in the control of infections and screening in the healthcare setting, horizontal and clonal transfer of carbapenemase genes occurs frequently in A. baumannii isolates. Accordingly, the transmission of CRAB isolates in hospital‐acquired or community‐acquired outbreaks must be tracked and monitored (Pfeifer et al ). Accordingly, pulsed field gel electrophoresis (PFGE) has been considered as the gold standard technique for tracking the source of infections (Johnson et al ).…”

Whole-Genome-Sequence-Based Characterization of Extensively Drug-Resistant Acinetobacter baumannii Hospital Outbreak

“…This is the first report of ST-502 and ST-2059 A. baumannii in Lebanon. Carbapenem-resistant ST-502 isolates have been reported previously in Brazil (33), Bulgaria (34), and South Africa (35). bla OXA-72 was first identified in 2004 in A. baumannii isolated from Taiwan, and since then it was detected in a few other countries, including Brazil, France, and the United States (36).…”

Genetics of Acquired Antibiotic Resistance Genes in Proteus spp.

“…The presence of bla NDM in Proteus spp. clinical isolates is still episodic in New Zealand (Williamson et al, 2012), in China (bla NDM−5 ) (Zhang et al, 2016), in Bulgaria (P. rettgeri) in 2016 (Pfeifer et al, 2017), in Vietnam (Tran et al, 2015). However, the bla NDM−1 gene was the first carbapenemase gene identified on a genomic island (PGI-1, PGI1-PmPEL) together with the bla VEB−6 gene in P. mirabilis isolate recovered from the urine of an hospitalized patient in France in 2012 (Girlich et al, 2015) (Figures 1, 3).…”