Molecular characterization of Listeria monocytogenes strains isolated from clinical samples in Urmia patients

Abstract

Abstract Background The foodborne bacterium Listeria monocytogenes is common in many settings, especially hospitals. The bacterium poses a significant threat to the healthcare system. Thus, work has been conducted to learn more about their serovars, pathogenicity, and antibiotic resistance patterns. Methods A total of 221 clinical samples were collected. All specimens were analyzed using the standard double enrichment procedure defined in ISO 11290:1. Gram staining and biochemical features were employed to identify L. monocytogenes. The disc diffusion assay was used to test the sensitivity of all L. monocytogenes strains to 13 antibiotics. Multiplex PCR was used to identify the presence of virulence genes and serogroups (1/2a, 1/2b, 1/2c, and 4b). ERIC-, REP-, and RAPD-PCR were used to perform genomic fingerprinting. Results 22 out of 221 samples contained L. monocytogenes on average (9.95%). 11 (12.79%) of the 86 stool samples tested positive for L. monocytogenes, with serotypes 1/2a, 1/2b, and 4b showing frequencies of 18.18%, 27.27%, and 654.55% respectively. Among these serotypes, 4b showed the highest distribution (57.14%). Trimethoprim/sulfamethoxazole (100%), and Tetracycline (90.91%), were the two antibiotics to which L. monocytogenes showed the highest levels of resistance, respectively. All 22 (100%) isolates were positive for the genes mpl, inlB, plcB, and prfA. The hlyA, actA, and iap genes were found in 95.45% of the isolates. The distribution of virulence genes llsX, ptsA, inlA was 8 (36.36%), 12 (54.55%) and 16 (72.43%), respectively. The genomic DNA from L. monocytogenes isolates in the samples was used in the ERIC-PCR to generate four fingerprint profiles. These profiles have a base range of 240 to 1500 and 6 to 14 bands overall. The REP- and RAPD-PCR of genomic DNA from L. monocytogenes from samples revealed amplification of numerous DNA fragments 100 to 3000 base (REP-PCR), 280 to 3000 base (RAPD-PCR) and were made up of 6 to 12 bands (REP-PCR) and 3 to 4 bands (RAPD-PCR). in Comparing the data from the dendrograms that were examined, which employed the Rep-type, RAPD-type, and ERIC-type techniques to count the bands, it was 12 − 6, 3–4, and 14 − 6, respectively, while the similarity for Rep-Type, RAPD-Type, and ERIC-Type was 100 − 53.80%, 96-54.30%, and 100 − 52.50%, respectively. Conclusions The findings, which strongly suggest that MDR L. monocytogenes 1/2a and 4b may be present among Iranian patients, should be viewed as having important public health ramifications.