Molecular characterization of selected multidrug resistant Pseudomonas from water distribution systems in southwestern Nigeria.
BACKGROUND
Persistence of antibiotic resistant bacteria, including multidrug resistant (MDR) pseudomonads, is an important environmental health problem associated with drinking water distribution systems (DWDS) worldwide. There is paucity of data on the molecular characteristics of antibiotic resistance genes and their mode of transfer among pseudomonads from DWDS located in resource-challenged areas such as southwestern Nigeria.


METHODS
MDR pseudomonads (n = 22) were selected from a panel of 296 different strains that were isolated from treated and untreated water in six DWDS located across southwest Nigeria. Primarily, the isolated pseudomonads strains were identified by 16S rDNA sequencing and antibiotic-resistance testing was completed using agar breakpoints assays. The final panel of strains of resistant to more than three classes of antibiotics (i.e. MDR), were further characterized by PCR genotyping, Sanger sequencing, and plasmid profiling.


RESULTS
Pseudomonad resistance to gentamicin and streptomycin ranged from 22.7 to 54.6 % while resistance to tetracycline, ceftiofur and sulphamethoxazole ranged from 40.9 to 77.3 %. The most commonly detected antibiotic resistance genes were tet(A) (31.8 % of isolates), sul1 (31.8 %), bla TEM (40.9 %) and aph(3″) (c) (36.4 %). Class 1 integron sequences were evident in 27.3 % of isolates and they harbored genes encoding resistance to aminoglycosides (aadA2, aadA1), trimethoprim (dfrA15, dfr7) and sulphonamide (sul1) while the plasmid ranged between 22 and 130 kb.


CONCLUSIONS
Pseudomonas spp, isolated from these DWDS possess resistance genes and factors that are of public and environmental health significance. Therefore, has the potential of contributing to the global scourge of resistance genes transfer in human, animals and environments, thereby, useful in the epidemiology of antimicrobial resistance.
Department of Biological Sciences, Federal University Dutsin-Ma, Dutsin-Ma, Katsina State, Nigeria. timmyayus2002@yahoo.com.
Ayodele T
AT
Adesoji
Department of Microbiology, University of Ibadan, Ibadan, Nigeria. aaogunjobi@hotmail.com.
Adeniyi A
AA
Ogunjobi
Department of Veterinary Public Health and Preventive Medicine, University of Ibadan, Ibadan, Oyo State, Nigeria. olatoyevet@yahoo.com.|Paul G. Allen School for Global Animal Health, Washington State University, Pullman, WA, USA. olatoyevet@yahoo.com.
Isaac O
IO
Olatoye
D000900:Anti-Bacterial Agents / Q000494:pharmacology; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D060766:Drinking Water / Q000382:microbiology*; D024901:Drug Resistance, Multiple, Bacterial; D005798:Genes, Bacterial; D060005:Genotyping Techniques; D006801:Humans; D032023:Integrons; D008826:Microbial Sensitivity Tests; D009549:Nigeria; D010957:Plasmids; D011549:Pseudomonas / Q000187:drug effects* / Q000235:genetics* / Q000302:isolation & purification; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA
D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D060766:Drinking Water; D012336:RNA, Ribosomal, 16S