Pseudomonas aeruginosa isolates of distinct sub-genotypes exhibit similar potential of antimicrobial resistance by drugs exposure.

Pseudomonas aeruginosa, a wide-spread opportunistic pathogen, often complicates clinical treatments due to its resistance to a large variety of antimicrobials, especially in immune compromised patients, occasionally leading to death. However, the resistance to antimicrobials varies greatly among the P. aeruginosa isolates, which raises a question on whether some sub-lineages of P. aeruginosa might have greater potential to develop antimicrobial resistance than others. To explore this question, we divided 160 P. aeruginosa isolates collected from cities of USA and China into distinct genotypes using I-CeuI, a special endonuclease that had previously been proven to reveal phylogenetic relationships among bacteria reliably due to the highly conserved 26-bp recognition sequence. We resolved 10 genotypes by I-CeuI analysis and further divided them into 82 sub-genotypes by endonuclease cleavage with SpeI. Eight of the 10 genotypes contained both multi-drug resistant (MDR) and less resistant isolates based on comparisons of their antimicrobial resistance profiles (ARPs). When the less resistant or susceptible isolates from different genotypes were exposed to eight individual antimicrobials, they showed similar potential to become resistant with minor exceptions. This is to our knowledge the first report to examine correlations between phylogenetic sub-lineages of P. aeruginosa and their potential to become resistant to antimicrobials. This study further alerts the importance and urgency of antimicrobial abuse control.