A National Surveillance of the Antibiotic Susceptibility of Acinetobacter baumannii in Saudi Arabia.

Most surveillance studies in Saudi Arabia have been single-centered or did not use the gold standard broth microdilution (BMD) antimicrobial susceptibility test. This is the first study from Saudi Arabia to evaluate the resistance profiles of Acinetobacter baumannii by using BMD on a national level. Between November 2022 and April 2023, isolates from several infection sites were collected from seven hospitals in seven regions of Saudi Arabia. On testing days, BMD was done following Clinical Laboratory Standards Institute standards. Antibiotic susceptibility percentages and MIC50 and MIC90 were calculated. One hundred A. baumannii isolates were included. The highest susceptibility was to tigecycline (39%) and aminoglycosides (22-25%). The MIC90 of all antibiotics were higher than the resistance breakpoint. All isolates (100%) were multidrug-resistant, of which 52% were classified as extensive-drug-resistant, and 42% were identified as pandrug-resistant. The isolates collected from the ear, peritoneal fluid, and the cerebrospinal fluid were all XDR, while 2/3 of the urine isolates (10/15; 66.7%), more than 1/2 of the skin/soft tissue and respiratory isolates (9/16; 56.3% and 22/43; 51.7%, respectively), and 3/8 (37.5%) of the blood isolates met this definition. Conversely, PDR isolates made up 5/8 of blood isolates (62.5%), 8/15 of body fluid isolates (57.14%), and 19/43 (44.2%) of respiratory isolates. A. baumannii showed a surprisingly high resistance to multiple commonly used antibiotics. Infection control policies and antimicrobial stewardship should be implemented by hospitals throughout the country to improve treatment, track resistance trends with local antibiograms, and prevent the development of resistant strains.