Antimicrobial Resistance Profiles and Clonal Relatedness of Pseudomonas aeruginosa Strains Recovered from Wounds Infections of Patients Presenting in Tigoni District Hospital, Kenya

Abstract

Pseudomonas aeruginosa is a leading cause of hospital infections and is intrinsically resistant to most antimicrobials. Emergence of multidrug resistant Pseudomonas aeruginosa has been reported and poses a great challenge in the management of the resultant infections. While a sizable amount of research has been done on these infections in developed countries, little is known about the susceptibility profiles and molecular diversity of strains recovered from wounds in Kenya. This cross-sectional study conducted in Tigoni District Hospital in rural Kenya sought to determine susceptibility profiles, molecular diversity of strains and risk factors associated with carriage of the organism in wound infections. This being a rural area, residents are presumed to be more likely to get wounds due to the manual nature of their work. Wound swabs were collected from 299 patients, and transported to the NMRL. Isolation was done on SBA and MacConkey with salt then drug susceptibility testing for Pseudomonas aeruginosa isolates using gentamicin, amikacin, ciprofloxacin ,piperacillin-tazobactam, ceftazidine, cefepime and meropenem. PCR was performed testing for β lactamase genes bla NDM-1, blaSHV and blaTEM. Fingerprinting analysis was done using the (GTG)5 primer to determine the phylogeny of recovered isolates. Statistical analysis of age and sex in relation to Pseudomonas aeruginosa carriage and recorded antimicrobial resistance patterns was done using IBM SPSS version 20 software (SPSS, Inc. Chicago, IL). Chi-square test was used to calculate P-value for risk factors associated carriage of Pseudomonas aeruginosa in wound infections. Binary logistic regression analysis was done to generate the adjusted odds ratio with 95% confidence interval, an alpha of less than 0.05 (P < 0.05) was considered statistically significant. Of the 299 patients 85 (28%) had positive wound carriage of Pseudomonas aeruginosa. This was highest among adults (94%) compared to children (6%)(P: 0.001, C.I:2.1-14.0, O.R:3.4). Wounds in females were more likely to be colonised (67%) compared to those in males at (33%) (P: 0.19, C.I:0.84-2.4, O.R: 1.42). Patients sourcing medication from a community chemist were more likely to have bacteria carriage compared to those who sourced from a hospital pharmacy (P: 0.001, C.1:3.01-8.86, O.R:5.17). Those who acquired antimicrobials without a doctor’s prescription were more likely to be colonized compared to those to those had (P: 0.001, C.I:3.01-8.86, O.R:5.17). Patients who did not complete dosage had a higher carriage (50.6%) compared to those that completed (49.4%). Highest antimicrobial resistance was recorded towards Ceftazidime (64%), Cefepime (52%) while Piperacillin-tazobactam was least resisted (20%). The isolates were more resistant towards Gentamicin (45%) and Amikacin (40%) compared to Ciprofloxacin (25%). Notable is the high resistance towards Meropenem (40%). Carriage of blaTEM, blaSHV and blaNDM was most common among strains showing resistance towards third generation cephalosporins, in addition to Amikacin and Meropenem for bla NDM-1Tight clustering was noted in isolates from diverse patients with a similarity of ≥ 80% was noted in 9 clusters based on isolates banding patterns. This appearance of blaNDM-1 linked to pervasive misuse of carbapenem is worrying. Strengthening antimicrobial stewardship is recommended