Publication: Antimicrobial susceptibility and molecular profiles of acinetobacter baumannii in Makkah hospitals, and the potential use of bacteriophage as a treatment option
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Date
2022-12
Authors
Raees, Fahad
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Abstract
Acinetobacter baumannii is an opportunistic Gram-negative pathogen that
frequently causes infections especially in intensive care settings worldwide including
Saudi Arabia. This organism is known to acquire resistant to almost all clinically available
antimicrobial agents. To understand the magnitude of A. baumannii acquisition in local
settings, 895 isolates were collected from King Abdullah Medical City Makkah, Al Noor
Hospital and Al Zahir Hospital of Makkah from 2013-2019. Vitek2® system was used for
identification of the organism and antimicrobial susceptibility test. Thirty MDR A.
baumannii isolates from King Abdullah Medical City Makkah and seven from Al Noor
Hospital were selected for whole genome sequencing. To study the role of bacteriophage,
sewage water from King Abdullah Medical City Makkah and Al Noor Hospital were
screened for clinical isolates A. baumannii lytic phenomenon. A few bacteriophage
candidates were found, but the subsequent lytic tests were negative. This phenomenon
was studied by reviewing the bacteriophage genomes integrated in the bacterial nucleic
acids. In this study, 70-80% of A. baumannii isolated from Makkah hospitals were found
to be resistant to commonly used antibiotics in intensive care units. There are increasing
trends of resistance to agents that been reserved to treat carbapenem-resistant A.
baumannii i.e. tigecycline and colistin. The sequence type (ST)-195 was the predominant
sequence type, contributed to 48.6% of A. baumannii isolations in Makkah hospitals.
There were three novel sequence types that associated with 18.9% of infections that need
further characterization. Among the β-lactamase resistant mutations, this study found blaADC-25 and blaOXA-66 were the most common with 86.5% and 83.8% respectively,
followed by blaOXA-23 and blaTEM-1D, both at 37.8%. This study also found 75.7% and
73.0% of the tested MDR A. baumannii isolated from Makkah hospitals acquired mph(E)
and msr(E) macrolides resistant genes respectively. The aminoglycosides resistance was
encoded mainly by aminoglycoside phosphor-transferase gene, aph(3′′)-Ib at 83.8% and
aminoglycoside O-phosphotransferase aph(6)-Id at 70.3%. Besides, these MDR isolates
were also acquired of sulphonamide resistant genes of sul1 (32.4%) and sul2 (18.9%). Part
of the core of this project was to find the potential bacteriophage that has capability to
infect and lyse A. baumannii cells. After extensive searching for bacteriophage from
sewage water of two tertiary care hospitals in Makkah, several bacteriophage candidates
were shortlisted, however these bacteriophages failed to perform lytic phenomenon
consistently. Almost one-fourth of MDR A. baumannii were found to acquire intact
bacteriophage genomes, indicated prophages condition. The whole genome sequence of
two MDR A. baumannii isolates (AB417 and AB552) were studied before and after
bacteriophage treatment indicated additional intact bacteriophage genomes were added in
isolate AB552. Three genomes of non-Acinetobacter bacteriophages was found to be
integrated in these MDR Acinetobacter series. In conclusion, this study found the resistant
rate of A. baumannii were more than 80% in Makkah hospitals which may lead to
treatment failure in clinical practice. Searching for a non-pharmacological approach by
means of using bacteriophage therapy showed inconsistent outcomes. With few treatment
options available, robust infection control strategies and antibiotic stewardship programs
are critical for preventing the spread of these resistant strains. Further research is very
critical to find alternative agents to treat MDR A. baumannii.
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Keywords
Acinetobacter baumannii