Genetic mechanisms of multidrug resistance among Klebsiella pneumoniae isolates from food-producing animals and humans in Lagos, Nigeria

Authors: ADENIPEKUN, EYITAYO - University Of Lagos; Jackson, Charlene; IWALOKUN, BAMIDELE - Nigerian Institute Of Medical Research; Frye, Jonathan; Barrett, John; Hiott, Lari; Woodley, Tiffanie; OLUWADUN, AFOLABI - Olabisi Onabanjo University

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 10/9/2016
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Klebsiella pneumoniae is an opportunistic pathogen that commonly causes hospital and community acquired bacterial infections in humans. The emergence and rapid spread of multi- drug resistant (MDR) K. pneumoniae is causing drug therapy failure amid patients leading to poor antibiotic management globally. This study determined multidrug resistance carriage rate, resistance genes and genetic relatedness of K. pneumoniae isolates from food-producing animals and humans in Lagos State, Nigeria. A cross-sectional study using random sampling was used to obtain samples from the studied communities from December 2012 to June 2013. A total of eleven (11) K. pneumoniae were isolated from fecal samples of healthy chicken (n=9) and cattle (n=2). Fifty (50) K. pneumoniae isolates were also recovered from stool and urine samples of asymptomatic out-patients attending Lagos state hospitals. Antimicrobial susceptibility testing against 22 antimicrobials was performed using broth microdilution with the SensititreTM system. Results were interpreted according to Clinical and Laboratory Standards Institute (CLSI) guidelines when defined. Resistance genes were identified by PCR and all obtained amplicons were sequenced; sequences were compared with those included in the GenBank database in order to identify ß-lactamase-encoding genes. Clonal types were determined by Pulsed-Field Gel Electrophoresis (PFGE). From the analysis of human isolates, 64% were resistant to ampicillin, 75% were resistant to =3 classes of antibiotics, and 4% were resistant to carbapenems (meropenem and ertapenem) and tigecycline (glycylcycline). MDR carriage rate was found to be 50% among human isolates. Animal isolates had 91% MDR carriage rate; 72.8% were resistant to more than 3 classes of antibiotics, but none were resistant to any carbapenems. K. pneumoniae isolates from human samples contained ESBL-encoding genes (blaCTX-M-15, blaTEM, blaSHV and blaOXA) and blaCMY; all MDR isolates contained more than one resistance gene. Animal isolates contained ESBL- encoding genes (blaCTX-M-15, blaSHV and blaTEM) and blaCMY. PFGE analysis determined genetic relatedness of K. pneumoniae isolates from cattle, chickens, pigs (swine) and humans (out-patients). Clusters determined if isolates grouped according to PFGE pattern, antimicrobial resistance phenotype and source. Isolates grouped into five clusters with a sub-cluster (A, A1-E) having >82% similarity. Overall, the clusters contained isolates that had slightly diversified phenotypic and genotypic characteristics; however, source appeared to be a dominant character for a few clusters. Cluster A1 contained only one isolate with =60% similarity to cluster A isolates. The genetic mechanisms of the MDR, ß-lactamase resistant K. pneumoniae in the community were blaCTX-15, blaTEM, blaSHV, blaOXA, and blaCMY. Moderate diversity among isolates suggested genetic relatedness among out–patients and food-producing animals. Direct contact with food animals and person-to-person contact are possible sources of out-patient infections in the community. Education of the community on antibiotic usage and subsequent restrictive usage of antibiotics in animal husbandry and among the community should be imposed.