Abstract:
Introduction: Acinetobacter baumannii is an
opportunistic pathogen, which can acquire new
resistance genes. Infections by carbapenem-re-
sistant A. baumannii (CRAB) in cancer patients
cause high mortality.
Methods: CRAB isolates from cancer patients
were screened for carbapenemase-encoding
genes that belong to Ambler classes (A), (B), and
(D), followed by genotypic characterization by
enterobacterial-repetitive-Intergenic-
consensus–polymerase chain reaction
(ERIC–PCR) and multilocus-sequence-typing
(MLST).
Results: A total of 94.1% of CRAB isolates co-
harbored more than one carbapenemase-en-
coding gene. The genes blaNDM, blaOXA-23-like,
and blaKPC showed the highest prevalence, with
rates of 23 (67.7%), 19 (55.9%), and 17 (50%),
respectively. ERIC-PCR revealed 19 patterns
(grouped into 9 clusters). MLST analysis identi-
fied different sequence types (STs) (ST-268, ST-
195, ST-1114, and ST-1632) that belong to the
highly resistant easily spreadable International
clone II (IC II). Genotype diversity indicated
the dissemination of carbapenem-hydrolyzing,
b-lactamase-encoding genes among genetically
unrelated isolates. We observed a high preva-
lence of metallo-b-lactamase (MBL)-encoding
genes (including the highly-resistant blaNDM
gene that is capable of horizontal gene transfer)
and of isolates harboring multiple carbapene-
mase-encoding genes from different classes.
Conclusion: The findings are alarming and call
for measures to prevent and control the spread
of MBL-encoding genes among bacteria causing
infections in cancer patients and other
immunocompromised patient populations.
