Genotypic Characterization of Aminoglycoside Resistance Genes from Bacteria Isolates in Selected Municipal Drinking Water Distribution Sources in Southwestern Nigeria

Abstract

BACKGROUND: Multi-drug Resistant (MDR) bacteria could leadto treatment failure of infectious diseases and could be transferredby non-potable water. Few studies have investigated occurrence ofAntibiotic Resistance Genes (ARGs) among bacteria includingAminoglycoside Modifying Genes (AMGs) from Drinking WaterDistribution Systems (DWDS) in Nigeria. Here, we aimed atcharacterization of AMGs from DWDS from selected states insouthwestern Nigeria.

METHODS: One hundred and eighty one (181) MDR bacteria thathad been previously characterized using 16S rDNA and showedresistance to at least one aminoglycoside antibiotic were selectedfrom treated and untreated six water distribution systems insouthwestern Nigeria. MDR bacteria were PCR genotyped for threeAMGs:aph (3 ́ ́) c , ant (3 ́ ́) b and aph(6)-1d d .

RESULTS: Out of 181 MDR bacteria genotyped, 69(38.12%) testedpositive for at least one of the genotyped AMGs. Highest (50,27.62%) detected gene was ant (3”) c followed by aph (3") c (33,18.23%). Combination of aph(3") c and ant (3") b in a single bacteriawas observed as the highest (14, 7.73%) among the detected genecombination. Alcaligenes sp showed the highest (10/20) occurrenceof ant (3") b while aph(3") c was the highest detected among Proteussp (11/22). Other bacteria that showed the presence of AMGsinclude: Acinetobacter, Aeromonas, Bordetella, Brevundimonas,Chromobacterium, Klebsiella, Leucobacter, Morganella, Pantoae,Proteus, Providencia, Psychrobacter and Serratia.

CONCLUSIONS: High occurrence of ant (3”) c and aph (3”) c amongthese bacteria call for urgent attention among public healthworkers, because these genes can be easily disseminated toconsumers of these water samples if present on mobile geneticelements like plasmids, integrons and transposons.