The history and evolution of outpatient parenteral antibiotic therapy (OPAT).

Outpatient parenteral antibiotic therapy (OPAT) is now a widely accepted and safe therapeutic option for carefully selected patients. Benefits include cost savings and improved patient satisfaction; risks include failure to adhere to care, unexpected changes in the underlying infection, and adverse drug and intravenous access events. We report on our 40-year experience with OPAT in a single healthcare system in the USA and highlight OPAT developments in several countries. We compared data on patients treated in our programme over two time periods: Period 1 from 1978 to 1990; and Period 2, calendar year 2014. In Period 2 paediatric patients were excluded. Between Periods 1 and 2, changes included an almost three-fold increase in the number of patients treated per year (80 vs. 229), treatment of more patients with severe orthopaedic-related infections (20% vs. 38%), a marked increase in the use of peripherally inserted central catheters to administer antibiotics (20% vs. 98%), a shorter duration of inpatient stay and a longer duration of OPAT (13 days vs. 24 days). Other changes in Period 2 included treatment of 20% of patients without antecedent hospitalisation, and use of carbapenems rather than cephalosporins as the most frequently administered agents. OPAT was safe, with rehospitalisation rates of 6% and 1% in Periods 1 and 2, respectively. We recommend increased access to structured OPAT teams and the development of standard definitions and criteria for important outcome measures (e.g. clinical 'cure' and unplanned hospital re-admissions). These steps are critical for patient safety and financial stewardship of resources.

Predictors of antimicrobial-resistant Escherichia coli in the feces of vegetarians and newly hospitalized adults in Minnesota and Wisconsin.

To determine whether poultry contact/consumption predicts colonization with antimicrobial-resistant Escherichia coli, 567 newly hospitalized patients and 100 vegetarians were assessed microbiologically and epidemiologically. Multivariable analysis showed that poultry contact/consumption, other dietary habits, and antimicrobial use did not significantly predict resistance. In contrast, foreign travel significantly predicted both trimethoprim-sulfamethoxazole resistance (prevalence ratio, 2.7 [95% confidence interval, 1.3-5.6]) and "any resistance" (total population), whereas intensive-care-unit exposure predicted any resistance (hospital patients). Thus, most of the individual-level exposures-including poultry contact/consumption-that had been expected to be significant risk factors for infection with antimicrobial-resistant E. coli did not prove to be such. Other exposures, including household-, community-, and population-level effects, may be more important.

Antimicrobial drug-resistant Escherichia coli from humans and poultry products, Minnesota and Wisconsin, 2002-2004.

The food supply, including poultry products, may transmit antimicrobial drug-resistant Escherichia coli to humans. To assess this hypothesis, 931 geographically and temporally matched E. coli isolates from human volunteers (hospital inpatients and healthy vegetarians) and commercial poultry products (conventionally raised or raised without antimicrobial drugs) were tested by PCR for phylogenetic group (A, B1, B2, D) and 60 virulence genes associated with extraintestinal pathogenic E. coli. Isolates resistant to trimethoprim-sulfamethoxazole, quinolones, and extended spectrum cephalosporins (n = 331) were compared with drug-susceptible isolates (n = 600) stratified by source. Phylogenetic and virulence markers of drug-susceptible human isolates differed considerably from those of human and poultry isolates. In contrast, drug-resistant human isolates were similar to poultry isolates, and drug-susceptible and drug-resistant poultry isolates were largely indistinguishable. Many drug-resistant human fecal E. coli isolates may originate from poultry, whereas drug-resistant poultry source E. coli isolates likely originate from susceptible poultry-source precursors.

Virulence factor profiles and phylogenetic background of Escherichia coli isolates from veterans with bacteremia and uninfected control subjects.

BACKGROUND: Escherichia coli is the most common cause of gram-negative bloodstream infections, causing an estimated 40,000 deaths from sepsis each year in the United States. The present study sought to determine specifically which virulence factors (VFs) and phylogenetic groups of E. coli are epidemiologically associated with bacteremia. METHODS: E. coli isolates from 63 veterans with bacteremia and rectal isolates from 71 matched uninfected control subjects were compared both for phylogenetic group and for the presence of VFs and O antigens. RESULTS: Bacteremia isolates exhibited a significantly greater prevalence of most VFs studied. In multivariate logistic regression analysis, ompT (outer membrane protein T) was the strongest VF predictor of bacteremia (P<.001). Despite the concentration of most individual VFs within group B2, bacteremia and rectal isolates differed little by phylogenetic distribution, a finding explained by the greater prevalence of VFs among bacteremia isolates than rectal isolates within groups B2 and D. CONCLUSIONS: Although phylogenetic group partially corresponds with virulence potential in E. coli bacteremia, VFs are more-powerful predictors of pathogenic potential. Bacteremia isolates exhibit an arsenal of VFs that distinguishes them from rectal isolates from uninfected hosts, which makes these differences attractive potential targets in vaccine or drug development.

Geographical distribution of antimicrobial resistance among Escherichia coli causing acute uncomplicated pyelonephritis in the United States.

The susceptibility to 12 antimicrobial agents of 165 Escherichia coli isolates from women with acute uncomplicated pyelonephritis of mild to moderate severity was analyzed by geographic region in the US. Ampicillin, trimethoprim, and trimethoprim/sulfamethoxazole resistance exhibited a descending prevalence gradient from west to east. Composite antimicrobial resistance phenotypes also exhibited significant regional differences, with a greater prevalence of most combined resistance profiles seen in the Pacific region of the US, but with significant north-south variation for combined ampicillin/sulfisoxazole resistance. These findings suggest geographical segregation of resistant clones and/or resistance elements among uropathogenic E. coli within the US, which is relevant both to clinical practice and to understanding the basis for the current epidemic of antimicrobial resistance in E. coli.

Antimicrobial resistance of Escherichia coli strains isolated from urine of women with cystitis or pyelonephritis and feces of dogs and healthy humans.

OBJECTIVE: To assess the prevalence and patterns of antimicrobial resistance among Escherichia coli strains isolated from the urine of women with cystitis or pyelonephritis and from fecal samples from dogs and healthy humans. DESIGN: Cross-sectional survey. SAMPLE POPULATION: Escherichia coli isolates from 82 women with cystitis, 170 women with pyelonephritis, 45 dogs, and 76 healthy human volunteers. PROCEDURE: Susceptibility to 12 antimicrobial agents was determined by means of disk diffusion testing as specified by the NCCLS. RESULTS: Overall, the 4 most common antimicrobial resistance patterns were resistance to ampicillin, sulfisoxazole, trimethoprim, and trimethoprim-sulfamethoxazole (n = 45 [12% of all isolates]); ampicillin alone (33 [9%]); ampicillin and sulfisoxazole (29 [8%]); and sulfisoxazole alone (14 [4%]). None of the isolates were resistant to ceftazidime, ciprofloxacin, nitrofurantoin, or piperacillin-tazobactam. Resistance was significantly more common and extensive among isolates from women with cystitis or pyelonephritis than among isolates from healthy humans or dogs. Resistance was least common among isolates from dogs. The only resistance phenotype that was more common among canine isolates than human isolates was resistance to sulfisoxazole alone. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that dogs are unlikely to be an important external reservoir of antimicrobial-resistant E. coli strains causing infections in humans. On the contrary the data suggest that dogs conceivably could acquire resistant E. coli strains from humans.