840 - First Report of Pseudomonas aeruginosa Isolates Harboring the CTX-M2 and PER genes in Algeria.

Background: Despite significant improvements in burn care, multidrug-resistant (MDR) Pseudomonas aeruginosa (PA) remains one of the most common causes of life-threatening infections in patients suffering from thermal injuries. The objective of this study is to investigate the prevalence of MDR PA producing Extended-Spectrum Beta-lactamases (ESBLs) and metallo-beta-lactamases (MBLs) in burn patients in Algeria.

Methods: Between April 2016 and October 2019, 47 non-redundant isolates of PA were collected from 47 burn patients admitted to the Department of Burns at the Military Hospital of Algiers in Algeria. Antibiotic susceptibility testing was performed by agar diffusion and the Phoenix automated method. Resistance genes were identified by PCR, and molecular typing of isolates was carried out by enterobacterial repetitive intergenic consensus (ERIC) sequences-polymerase chain reaction  (PCR).

Results: Among the 47 non-redundant MDR PA strains isolated, 59.57% were phenotypically ESBLs-positive, and 100% were phenotypically MBL-positive. The ESBL-positive isolates were subsequently screened for five groups of bla genes encoding ESBL-type enzymes, namely CTX-M2, PER, TEM, SHV, VEB, and GES. Out of the 28 ESBL-producing strains, 23 (82.14%)  were CTX-M2 positive; 18 (38.29%) were PER positive, and 16 (34.04%) were TEM positive, while 5 (17.9%) were co-harboring CTX-M2, TEM, and PER genes. The SHV, VEB, and GES genes were not detected in any of the ESBL positive isolates. Since all isolates were MBL-positive, all 47 strains were screened for the NDM-1, IMP, VIM genes that produce MBLs; however, none of these genes were detected. Additional screening for the OprD gene demonstrated that 45 (95.74%) of the isolates were positive for this gene. Finally, ERIC PCR revealed 6 distinct PA clones among the CTX-M2 positive strains.Table 1: Occurrence of beta-lactamase genes in relation to the antimicrobial susceptibility profiles of the PA isolates.


Conclusion: This is the first report of CTX-M2-producing PA in the North Africa region and the first to detect CTX-M2-positive and PER-positive PA clinical isolates in Algeria, therefore demonstrating the spread of such MDR strains in this part of the world. Identification of genotypic alterations that confer antibiotic resistance is critical in determining effective antimicrobial strategies. Hence, these findings could potentially guide antibiotic choice decisions.World map with countries where PER- and CTX-M2-postive Pseudomonas aeruginosa isolates have been reported.