Association between Antibiotic Resistance and the Expression of Dr Adhesin among Uropathogenic <i>Escherichia coli</i>

Abstract

Background: Urinary tract infections (UTIs) are a significant health problem and Escherichia coli has been exported to be the primary pathogen in approximately 80% of cases. E. coli express structures called adhesins, fimbriae or pili that help them bind to specific tissue receptors. One such adhesin is Dr, which binds to the complement decay-accelerating factor (CD55) on the host cell. The purpose of the present study was to review the epidemiology and antimicrobial sensitivity spectrum of Dr adhesin-bearing E. coli isolates in women with UTI. Methods and Results: A total of 337 uropathogenic E. coli isolates were collected, and mannose-resistant hemagglutination was observed in 43%, while 12.4% expressed Dr adhesin. All 337 uropathogenic E. coli isolates were found to be resistant to penicillin, oxacillin, bactericin and cloxacillin. None of the isolates was resistant to quinolones. The resistance to sulfamethoxazole was most common (90%), followed by nalidixic acid (51%) and ampicillin (41%). Interestingly, uropathogenic E. coli expressing Dr adhesin had a high incidence of ampicillin resistance (83%), and only 17% of the Dr-bearing isolates were found to be resistant to an ampicillin/sulbactum combination. Conclusion: These results indicate that UTIs may be successfully treated with ampicillin in combination with a β-lactamase inhibitor, so that selective colonization by Dr adhesin-bearing uropathogenic E. coli is prevented, which is probably promoted by treating these patients with ampicillin alone.

Association of Antibiotic Resistance in Agricultural Escherichia coli Isolates with Attachment to Quartz

“…This work was motivated by the fact that antibiotic resistance and attachment factors can be encoded together on mobile genetic elements (23), leading to the proposition of a significant relationship between the attachment phenotype and antibiotic resistance. This relationship has previously been observed with clinical isolates (2,24,25); the work presented here is the first investigation of agricultural isolates. We found that resistance to 6 of the 13 tested antibiotics is significantly and positively associated with quartz attachment (Fig.…”

“…For example, Liverell's study showed that antibiotic-resistant bacteria have increased adherence to human intestinal cells relative to antibiotic-sensitive strains (28). Ampicillin resistance has been associated specifically with P pili and Dr-type attachment factors (2,24,25), and tobramycin resistance has been associated with afimbrial adhesion, S fimbriae, and P pili (2). This relationship is not surprising when one considers that mobile genetic elements carrying both attachment and resistance-associated genes have been found in E. coli (29,39).…”

Decreased Prevalence of Virulence Factors among Ciprofloxacin-Resistant Uropathogenic Escherichia coli Isolates

“…This binding event prevents bacterial washout, breaks the mucosal barrier, and initiates the host immune response (2). We realize that there are a variety of other adhesins and virulence factors that are involved in uropathogenesis, and a subset of urinary tract infection isolates carry the Dr/Afa adhesins (3,10). This study focuses on P fimbriae because (i) they may be the primary adherence factor isolated from uropathogenic isolates of E. coli (4,28); (ii) they trigger the host immune response (2); and (iii) they fulfil Koch-Henle molecular postulates by conferring on an avirulent nonfimbriated strain the ability to induce a host response in the human urinary tract (30).…”

Relationship between virulence and antimicrobial resistance in bacteria

“…On the contrary, some studies have reported that sub-MICs of ciprofloxacin increase their adhesiveness, and hence the risk of colonization by UPEC strains expressing mannose-resistant adhesins different from type P [38]. Kachroo [39] found an association between antimicrobial resistance and the expression of Dr adhesin among UPEC. They analysed 337 UPEC strains and found that only 12.4% expressed this adhesin.…”