Extended-spectrum β-lactamase/AmpC-producing uropathogenic Escherichia coli from HIV patients: do they have a low virulence score?

Abstract

Extended-spectrum b-lactamase (ESBL) production and quinolone resistance are often associated in enterobacteria. Prior exposure to 3G cephalosporins/quinolones accelerates the risk of resistance to both these groups of antibiotics. Hence, information on the antimicrobial resistance pattern of uropathogenic Escherichia coli (UPEC) isolates is important to better formulate the guidelines for the empirical therapy of urinary tract infection in the context of HIV/ AIDS. The aim of this study was to determine the incidence of ESBL/AmpC and fluoroquinolone (FQ) resistance among urinary E. coli isolates and to establish the association of extraintestinal virulence and phylogenetic distribution with antibiotic resistance and host immunocompromisation. Accordingly, 118 urinary Escherichia coli isolates from HIV (n576) and non-HIV antenatal patients (n542) from Chennai, South India, were analysed for the presence of five virulence-associated genes (VAGs): pap, sfa/foc, afa/dra, iutA and kpsMII. Compared with the susceptible HIV isolates, the majority of the ESBL + AmpC + FQ R isolates harboured iutA (66.7 %) and pap (40 %). The FQ-resistant HIV isolates were significantly enriched for iutA (67.8 %) and kpsMII (47.5 %) and qualified as UPEC (54.2 %), while a majority of the FQ-susceptible isolates from the non-HIV patients were found to harbour pap (48.4 %), sfa/foc (41.9 %) and kpsMII (48.4 %) and were classified as UPEC (40.5 %). We conclude that antibiotic-resistant (ESBL + AmpC + and/or FQ R ) phylogroup D isolates with limited virulence are competent enough to establish infections in HIV patients, while among non-HIV patients, an array of virulence factors is essential for E. coli to overcome host defences irrespective of antibiotic resistance. INTRODUCTIONThe liberal use of quinolones and b-lactams has triggered bacterial resistance worldwide. Urinary Escherichia coli are increasingly reported to exhibit resistance to the conventional front-line antibiotic ciprofloxacin (Lüthje & Brauner, 2010). The recent EAU (European Association of Urology) guidelines (2011; see http://www.uroweb.org/guidelines/ online-guidelines/) recommend the use of Group 3a/b cephalosporins (cefotaxime, ceftazidime, cefoperazone) for the treatment of complicated urinary tract infections and urosepsis (Grabe et al., 2011). However, emergence of b-lactam resistance mediated by extended-spectrum blactamases (ESBLs) and group 1 AmpC cephalosporinases (especially plasmid-mediated AmpC b-lactamasesPMACBLs) is a major global problem (Winokur et al., 2001;Lampri et al., 2012). ESBL/AmpC-producing organisms are of paramount concern as they limit therapeutic options, cause treatment failures and increase the cost/ duration of hospitalization (Odeh et al., 2002). Emerging resistance in E. coli is frequently due to the irrational use of antibiotics and is associated with high mortality rates. Hence, rapid detection of such strains is a prerequisite to limit their dissemination and for the selection of appropriate antimicrobial therapy, which is frequentl...

Characterization of bacterial antimicrobial peptides active against Campylobacter jejuni

“…85,86 The mass of the peptide expressed in yeast was consistent with the predicted mass based on the amino acid sequence, and not with the reported mass of 3340 Da. While E 50-52 produced in yeast was antimicrobially active against Gram-positive bacteria such as L. monocytogenes, it was not active against Gramnegative bacteria including C. jejuni.…”

“…85 E 50-52 expressed as a fusion protein in E. coli was reported to be active, following cleavage, against the Gram-negative E. coli as well as Gram-positive S. aureus and L. monocytogenes. 86 However, no testing against C. jejuni was reported. Whether or not this indicates that similar post-translational modifications may occur in E. coli and E. faecium is unclear.…”

Antibiotic-Resistant Infections and Treatment Challenges in the Immunocompromised Host

“…One study found that HIV-infected individuals with uropathogenic E coli were more likely to have ESBL and AmpC coproducers than non-HIV-infected individuals (71.1% vs 35.7%), although ESBL producers (without AmpC) were more common among non-HIV-infected individuals (16.7% vs 3.9%). 116 In a South African study, 13 of 25 HIVinfected children with Enterobacteriaceae causing bacteremia were found to be infected with ESBL isolates. 103 In the same study, nasopharyngeal colonization was investigated and found that of the 32 children with nasal colonization by Enterobacteriaceae, 16 (50%) were ESBL isolates.…”

“…Another study investigating ESBL uropathogens found that fluoroquinolone resistance occurred in 77.6% of isolates from HIV-infected individuals versus 26.2% non-HIVinfected individuals. 116 Data on ESBL pathogens among HIV-infected individuals is also sparse, but the limited data do show ESBL pathogens to be common in this population. One study found that HIV-infected individuals with uropathogenic E coli were more likely to have ESBL and AmpC coproducers than non-HIV-infected individuals (71.1% vs 35.7%), although ESBL producers (without AmpC) were more common among non-HIV-infected individuals (16.7% vs 3.9%).…”

Resistance Patterns of Escherichia coli in Women with Uncomplicated Urinary Tract Infection Do Not Correlate with Emergency Department Antibiogram

“…At our institution, patients # 18 years of age are treated in the pediatric ED. The following patients were excluded: those who had a known urologic abnormality or comorbidity, those with an indwelling Foley catheter or who had a catheter removed within the previous 14 days, anyone with a history of kidney stones, those with diabetes mellitus, those who did not speak English, those who had received TMP-SMX prophylaxis within the previous 6 months, anyone with the human immunodeficiency virus (HIV) with no CD4 count on file or a CD4 count < 350 cells/mm 3 , those who had been transferred from another health care facility, and those who were pregnant (8). Pregnant women were excluded, as these patients are considered to have complicated infections according to the IDSA guidelines (1) .…”