RESUMO
Objectives: To determine the in vitro susceptibility of Enterobacterales (nâ=â5457) and Pseudomonas aeruginosa (nâ=â1949) isolated from hospitalized patients in Africa (three countries) and the Middle East (five countries) in 2018-20 to a panel of 11 antimicrobials and to identify ß-lactamase/carbapenemase genes in isolates with meropenem-non-susceptible and/or ceftazidime/avibactam-resistant phenotypes. Methods: CLSI broth microdilution testing generated MICs that were interpreted using CLSI (2021) breakpoints. ß-Lactamase/carbapenemase genes were identified using multiplex PCR assays. Results: Enterobacterales isolates were highly susceptible to amikacin (96.7%), ceftazidime/avibactam (96.6%) and tigecycline (96.0%), and slightly less susceptible to meropenem (94.3%). In total, 337 Enterobacterales isolates (6.2% of all Enterobacterales isolates) carried one or more carbapenemase genes: 188 isolates carried a serine carbapenemase (178 OXA, 10 KPC) and 167 isolates carried an MBL (18 isolates carried both an MBL and an OXA). NDM-1 was the most common MBL identified (64.1% of NDM enzymes; 59.9% of all MBLs). OXA-48 (47.8%) and OXA-181 (38.8%) were the most common OXAs detected. P. aeruginosa isolates were most susceptible to ceftazidime/avibactam (89.1%) and amikacin (88.9%). Only 73.1% of P. aeruginosa isolates were meropenem susceptible. The majority (68.1%) of P. aeruginosa isolates tested for carbapenemase/ß-lactamase genes were negative. In total, 88 isolates (4.5% of all P. aeruginosa isolates) carried one or more carbapenemase genes: 81 isolates carried an MBL and 8 carried a GES carbapenemase (1 isolate carried genes for both). Conclusions: Carbapenemase detection was closely associated with meropenem-non-susceptible phenotypes for Enterobacterales (89.1%) but not for P. aeruginosa (24.2%). Wide geographic variation in carbapenemase type and frequency of detection was observed.
RESUMO
OBJECTIVES: To assess the in vitro activity of ceftazidime/avibactam against a recent, 2015-18, collection of clinical isolates of Gram-negative bacilli from Middle Eastern and African countries with a focus on isolates from ICUs and with MDR and difficult-to-treat resistance (DTR) phenotypes. METHODS: Antimicrobial susceptibility testing of 4608 isolates of Enterobacterales (997 isolates from ICU patients) and 1358 isolates of Pseudomonas aeruginosa (374 isolates from ICU patients) was performed by CLSI broth microdilution methodology in a central laboratory. MICs were interpreted using both CLSI (2020) and EUCAST (2020) MIC breakpoints. RESULTS: Most isolates of Enterobacterales (Middle East: ICU, 99.1% susceptible, non-ICU, 99.1%; Africa: ICU, 96.9% susceptible, non-ICU, 98.3%) and P. aeruginosa (Middle East: ICU, 93.4%, non-ICU, 92.1%; Africa: ICU, 89.8%; non-ICU, 94.1%) were susceptible to ceftazidime/avibactam. Applying CLSI and EUCAST breakpoints, MDR rates were similar for Enterobacterales (27.8%-36.0% of isolates) and P. aeruginosa (25.0%-36.4%) while DTR rates were lower for Enterobacterales (1.6%-1.8%) than for P. aeruginosa (5.2%-7.4%). Percentage susceptible rates for ceftazidime/avibactam for MDR Enterobacterales were 96.8%-97.5% (Middle East) and 92.5%-94.3% (Africa) while rates for P. aeruginosa were 70.1%-80.0% (Middle East) and 69.5%-78.2% (Africa). 60.5%-65.8% (Middle East) and 38.9%-52.2% (Africa) of isolates of Enterobacterales with DTR phenotypes were ceftazidime/avibactam susceptible as were 29.2%-31.1% (Middle East) and 28.2%-35.8% (Africa) of DTR P. aeruginosa. CONCLUSIONS: Overall, the isolates of Enterobacterales and P. aeruginosa tested from Middle Eastern and African countries were highly susceptible to ceftazidime/avibactam. Most MDR and many DTR isolates of Enterobacterales and P. aeruginosa were susceptible to ceftazidime/avibactam.