ESβL and MβL Production in Gram-Negative Bacteria Isolated From HIV Seropositive Individuals

Background: Extended-spectrum β-lactamase (ESβL) or metallo-β-lactamase (MβL) production by gramnegative bacteria in immunocompromised patients poses a serious therapeutic challenge for infection control and is associated with infections with a higher morbidity/mortality, especially in developing countries. This study aimed to phenotypically evaluate the production of ESβL as well as MβL in ۷۵ gramnegative bacterial isolates from clinical samples of the human immunodeficiency virus (HIV) positive individuals. Methods: Bacterial identification was by chromogenic media, analytical profile index ۲۰ E, and ۲۰ NE kits, and ESβL production was tested by double-disc synergy test (DDST) and combination disc method, while MβL production was screened with imipenem ethylene diamine tetra-acetic acid (EDTA) combined disc and EDTA-disc potentiation with ceftazidime. Results: Altogether, ۵۷ isolates (۷۶.۰%) produced ESβL either with DDST (۶), combination disc method (۴۹), or both (۲). DDST detected the ESβL enzyme in ۱۰.۷% of the tested isolates which were all Pseudomonas aeruginosa. None of the bacterial isolates revealed MβL production with the imipenem/imipenem-EDTA method, whereas ۲۶.۷% of tested isolates produced MβL with EDTA-disc potentiation using ceftazidime out of which ۶۵.۰% were P. aeruginosa. Moreover, ESβL/MβL co-production was evident in ۲۲.۷% of the tested bacterial isolates with P. aeruginosa constituting ۶۴.۷%. Conclusion: ESβL and MβL co-production among the studied isolates indicates a heightened resistance to β-lactam antibiotics, suggesting grave health consequences, especially in immunocompromised individuals with already limiting therapeutic options in the region. The study revealed higher ESβL production compared to MβL production in isolates, with the predominating producing specie being P. aeruginosa, and higher ESβL and MβL detection by the combination disc method and EDTA-disc potentiation using ceftazidime, respectively.

Keywords:

HIV , Extended-spectrum β-lactamase , Metallo-β-lactamase , Double-disc synergy test , Gramnegative bacteria