The relationship between bacterial sources and genotype to the antimicrobial resistance pattern of Burkholderia pseudomallei

Abstract

Background:Melioidosis is a fatal emerging infectious disease of both man and animal caused by bacteria Burkholderia pseudomallei. Variations were suggested to have existed among the different B. pseudomallei clinical strains/genotypes which may implicate bacterial susceptibility and resistance toward antibiotics.Aim:This study was designed to determine whether the phenotypic antibiotic resistance pattern of B. pseudomallei is associated with the source of isolates and the genotype.Materials and Methods:A collection of 111 B. pseudomallei isolates from veterinary cases of melioidosis and the environments (soil and water) were obtained from stock cultures of previous studies and were phylogenetically characterized by multilocus sequence typing (ST). The susceptibility to five antibiotics, namely meropenem (MEM), imipenem, ceftazidime (CAZ), cotrimoxazole (SXT), and co-amoxiclav (AMC), recommended in both acute and eradication phases of melioidosis treatment were tested using minimum inhibitory concentration antibiotics susceptibility test.Results:Majority of isolates were susceptible to all antibiotics tested while few resistant strains to MEM, SXT, CAZ, and AMC were observed. Statistically significant association was found between resistance to MEM and the veterinary clinical isolates (p<0.05). The likelihood of resistance to MEM was significantly higher among the novel ST 1130 isolates found in veterinary cases as compared to others.Conclusion:The resistance to MEM and SXT appeared to be higher among veterinary isolates, and the novel ST 1130 was more likely to be resistant to MEM as compared to others.

Diversity of Colony Morphotypes, Biochemical Characteristics, and Drug Susceptibility Patterns of Burkholderia pseudomallei Isolated from Humans, Animals, and Environmental Sources in Thailand

“…Although, meropenem and imipenem are used as an alternative to ceftazidime [26], meropenem and imipenem showed 100 % susceptibility, except for meropenem for human isolates (98.9 %) and imipenem for soil sources (90.9 %). The susceptibility rate for meropenem and imipenem in our study was higher than previous studies, which reported 100% susceptibility for imipenem [25]. Ciprofloxacin, a member of fluoroquinolones, was used individually or combined with doxycycline to treat acute melioidosis [27].…”

“…There were many patterns of antimicrobial drug resistance of B. pseudomallei in our study as shown in Table 4. Monitoring of antimicrobial resistance of B. pseudomallei isolates, not only in clinical specimens but also in animal and environmental isolates, needs to be conducted regularly to guide empiric therapy for human melioidosis, as it causes high mortality [25]. We found that mono-resistance to ceftazidime, the first drug of choice in the acute phase for melioidosis treatment, was 3.0 % of B. pseudomallei from soil sources.…”

“…Our results were consistent with Sadiq et al study (2018) that reported B. pseudomallei ceftazidime resistance in soil isolates but not in animal and water isolates. They proposed that the different rates of antimicrobial drug resistance were associated with different genotypes of the isolates [25].…”