Prevalence of tetracycline resistance genes among multi-drug resistant bacteria from selected water distribution systems in southwestern Nigeria. Issue 1 (December 2015)

• Record Type: Journal Article
• Authors: Adesoji, Ayodele.; Ogunjobi, Adeniyi.; Olatoye, Isaac.; Douglas, Douglas.
• Is Part Of: Annals of clinical microbiology and antimicrobials. Volume 14:Issue 1(2015)
• Page Start: 1
• Page End: 8
• Publication Date: 2015-12
• Subjects: Tetracycline resistance -- Multidrug resistance -- Water treatment -- 16S rDNA library; Medical microbiology -- Periodicals; Anti-infective agents -- Periodicals; 616.9041
• DOI: 10.1186/s12941-015-0093-1
• Languages: English
• ISSNs: 1476-0711

Abstract

Abstract Background Antibiotic resistance genes [ARGs] in aquatic systems have drawn increasing attention they could be transferred horizontally to pathogenic bacteria. Water treatment plants (WTPs) are intended to provide quality and widely available water to the local populace they serve. However, WTPs in developing countries may not be dependable for clean water and they could serve as points of dissemination for antibiotic resistant bacteria. Only a few studies have investigated the occurrence of ARGs among these bacteria including tetracycline resistance genes in water distribution systems in Nigeria. Methodology Multi-drug resistant (MDR) bacteria, including resistance to tetracycline, were isolated from treated and untreated water distribution systems in southwest Nigeria. MDR bacteria were resistant to >3 classes of antibiotics based on break-point assays. Isolates were characterized using partial 16S rDNA sequencing and PCR assays for six tetracycline-resistance genes. Plasmid conjugation was evaluated usingE. coli strain DH5α as the recipient strain. Results Out of the 105 bacteria, 85 (81 %) and 20 (19 %) were Gram- negative or Gram- positive, respectively. Twenty-nine isolates carried at least one of the targeted tetracycline resistance genes including strains ofAeromonas, Alcaligenes, Bacillus, Klebsiella, Leucobacter, Morganella, Proteus and a sequence matching a previously uncultured bacteria.Tet (A) was the most prevalent (16/29) followed bytet (E) (4/29) andtet30 (2/29).Tet (O) was not detected in any of the isolates.Tet (A) was mostly found withAlcaligenes strains (9/10) and a combination of more than one resistance gene was observed only amongstAlcaligenes strains [tet (A) + tet30 (2/10), tet (A) + tet (E) (3/10), tet (E) + tet (M) (1/10), tet (E) + tet30 (1/10)].Tet (A) was transferred by conjugation for fiveAlcaligenes and twoE. coli isolates. Conclusions This study found a high prevalence of plasmid-encodedtet (A) amongAlcaligenes isolates, raising the possibility that this strain could shuttle resistance plasmids to pathogenic bacteria.