Prevalence of bla 𝐶𝑇𝑋 - 𝑀 , bla 𝑇𝐸𝑀 , and bla 𝑆𝐻𝑉 Genes among Extended-spectrum β -lactamases-producing Clinical Isolates of Enterobacteriaceae in Different Regions of Sudan

Abstract

Background: This study aimed to characterize bla 𝐶𝑇𝑋 - 𝑀 , bla 𝑇𝐸𝑀 , and bla 𝑆𝐻𝑉 genes among extended-spectrum beta-lactamases (ESBLs)-producing Enterobacteriaceae species in different regions of Sudan. Methods: In this cross-sectional study, different clinical samples (n = 985) were collected randomly from symptomatic patients from four geographical regions of Sudan and cultured on chromogenic media. Following bacterial identification, phenotypic screening of ESBLs was done according to CLSI guidelines using cefotaxime (30 μg), ceftazidime (30 μg), and cefepime (30 μg) discs with and without clavulanic acid. The DNA was extracted by guanidine hydrochloride protocol, and then conventional PCR was used to detect bla 𝐶𝑇𝑋 - 𝑀 , bla 𝑇𝐸𝑀 , and bla 𝑆𝐻𝑉 genes. The presence of genes' subtypes was characterized by DNA Sanger sequencing for selected samples. Results: Enterobacteriaceae represented 31% (305/985) of all isolates, 42 (128/305) of which were ESBLs producer, confirmed by phenotypic confirmatory test (75% [96/128] of them were positive for bla 𝐶𝑇𝑋 - 𝑀 genes, 61% [78/128] for bla 𝑇𝐸𝑀 genes, and 38% [48/128] for bla 𝑆𝐻𝑉 genes). Fourteen isolates (11%) were negative for all genes. Forty-eight percent (63/75) of Escherichia coli isolates were positive for bla 𝐶𝑇𝑋 - 𝑀 , while in Klebsiella pneumoniae, the dominant gene was bla 𝑇𝐸𝑀 (82%) and had a low amount of bla 𝑆𝐻𝑉 (59%). There was a significant association (P-value = 0.001 for all except for chloramphenicol, P = 0.014, and amikacin, P = 0.017) between resistance to third-generation cephalosporins and ciprofloxacin, nalidixic acid, meropenem, chloramphenicol, and amikacin. Forty-two percent (40/96) of CTX-M-positive isolates were in Gizera State, 33% (32.96) in Sinnar, 24% (23/96) in Khartoum, and 1% (1/96) in White Nile. Conclusion: We conclude that bla 𝐶𝑇𝑋 - 𝑀 genes are the most dominant genes in ESBLs-producing isolates and are more prevalent in big cities than in rural areas.

Keywords

• phenotypic, bla𝐶𝑇𝑋-𝑀, bla𝑇𝐸𝑀, and bla𝑆𝐻𝑉 esbls genes, enterobacteriaceae, sudan