The Occurrence of Resistomes, Virulence Factors and Clonal Diversity of Escherichia coli and Staphylococci Isolated from the Semen of Men Attending Infertility Clinic in Lagos

Abstract

Abstract Male factor infertility accounts for 40–60% of global couples suffering from infertility. Multiple antibacterial resistances have constituted a serious impediment against the effective eradication of non-specific bacteria etiology of male infertility; resistant genes are spread within and across bacterial species; producing progeny that are difficult to treat. This study, analyzed resistance genes, virulence factors, and clonal characteristics of E. coli and Staphylococci recovered from the semen of infertile men attending urology clinics in Lagos. A total of 16 E. coli and 48 Staphylococci isolated from 226 infertile men were found to be MDR and were suspected of harboring resistomes. Escherichia coli specific oligonucleotide primers were designed according to TEM, SHV, CTX-M-type and OXA β-lactamase, TEcoli (tuf), and bac DNA sequences, and Staphylococci Mec A, Fem A, ermA and others genes deposited in the GenBank were identified using PCR method. Clonal characteristics and biodiversity were determined by RAPD using oligonucleotides S30 5׳- GTGATCGCAG that had non-palindromic sequences. The DNA fingerprints of the isolates were compared for biodiversity by visual inspection of the band profiles. The gel images were digitalized and stored as TIFF. These files were converted, normalised, and analysed with GelWorks 1D software (version 3.00, UV products, England). DNA fingerprints detected by computer were carefully verified by visual examination to correct unsatisfactory detections. Genetic relationships were established by scoring the presence (1) or absence (0) of each RAPD polymorphic band. The percent of similarity between the strains was estimated by using the coefficient of Dice. Cluster analysis of similarity matrices was performed by UPGMA tool. The data were submitted to the computer programme to transform the polymorphic bands of the oligonucleotide into a dendrogram. Escherichia coli had a 25% prevalence of blaCTx-M gene and Staphylococci had 22.6% MecA and 12.9% FemA genes. Phylogenetically, E. coli had a narrow diversity of 2 main groups and 3 clusters from a single genetic origin, with > 50% similarity. Group 1 had a different genetic identity and required further sequencing as a local strain from Lagos. Staphylococci were more diverse as there were 6 main groups and 11 clusters with 10–90% similarity. Group 4 had a different genetic origin and requires further sequencing as a local strain. This study concludes the relatively high occurrence of the blaCTx-M gene among E. coli and MecA genes among Staphylococci and these calls for concern. The presence of non-typeable genotypes is novel and underscores the need for a national programme for bacterial typing.