Impact Of Antibiotic Resistance Research Articles

Infection with Helicobacter pylori: Prevalence, research and impact of antibiotic resistance

Infection with Helicobacter pylori: Prevalence, research and impact of antibiotic resistance

Impact of antibiotic resistance in the management of ocular infections: the role of current and future antibiotics

This article reviews the effects of the increase in bacterial resistance on the treatment of ocular infections. Interpretive assessment. Literature review and interpretation. Ocular bacterial infections include conjunctivitis, keratitis, endophthalmitis, blepharitis, orbital cellulitis, and dacryocystitis. Treatment for most ocular bacterial infections is primarily empiric with broad-spectrum antibiotics, which are effective against the most common bacteria associated with these ocular infections. However, the widespread use of broad-spectrum systemic antibiotics has resulted in a global increase in resistance among both Gram-positive and Gram-negative bacteria to a number of the older antibiotics as well as some of the newer fluoroquinolones used to treat ophthalmic infections. Strategies for the prevention of the increase in ocular pathogen resistance should be developed and implemented. In addition, new antimicrobial agents with optimized pharmacokinetic and pharmacodynamic properties that have low toxicity, high efficacy, and reduced potential for the development of resistance are needed. New antimicrobial agents that treat ocular infections effectively and have a low potential for the development of resistance could be a part of strategies to prevent the global increase in ocular pathogen resistance.

An economic model for the prevention of MRSA infections after surgery: non-glycopeptide or glycopeptide antibiotic prophylaxis?

Surgical site infection is commonly caused by Staphylococcus aureus. The multiresistant strains (MRSA) are resistant to most antibiotic prophylaxis regimens. Our aim was to explore whether there is a threshold of MRSA prevalence at which switching to routine glycopeptide-based antibiotic prophylaxis becomes cost-effective. An indicative model was designed to explore the cost-effectiveness of vancomycin, cephalosporin or a combination, in patients undergoing primary hip arthroplasty. If the MRSA infection rate is equal to or above 0.25% and the rate of other infections with cephalosporin prophylaxis is equal to or above 0.2%, use of the combination antibiotic prophylaxis is optimal. Modelling the cost-effectiveness of interventions for MRSA prevention is complex due to uncertainty around resistance and effectiveness of glycopeptides. The indicative model provides a framework for evaluation. More work is needed to understand the impact of antibiotic resistance over time in these currently effective antibiotics.

Staphylococcus aureus Bacteraemia in a Tropical Setting: Patient Outcome and Impact of Antibiotic Resistance

BackgroundMost information on invasive Staphylococcus aureus infections comes from temperate countries. There are considerable knowledge gaps in epidemiology, treatment, drug resistance and outcome of invasive S. aureus infection in the tropics.MethodsA prospective, observational study of S. aureus bacteraemia was conducted in a 1000-bed regional hospital in northeast Thailand over 1 year. Detailed clinical data were collected and final outcomes determined at 12 weeks, and correlated with antimicrobial susceptibility profiles of infecting isolates.Principal FindingsNinety-eight patients with S. aureus bacteraemia were recruited. The range of clinical manifestations was similar to that reported from temperate countries. The prevalence of endocarditis was 14%. The disease burden was highest at both extremes of age, whilst mortality increased with age. The all-cause mortality rate was 52%, with a mortality attributable to S. aureus of 44%. Methicillin-resistant S. aureus (MRSA) was responsible for 28% of infections, all of which were healthcare-associated. Mortality rates for MRSA and methicillin-susceptible S. aureus (MSSA) were 67% (18/27) and 46% (33/71), respectively (p = 0.11). MRSA isolates were multidrug resistant. Only vancomycin or fusidic acid would be suitable as empirical treatment options for suspected MRSA infection.Conclusions S. aureus is a significant pathogen in northeast Thailand, with comparable clinical manifestations and a similar endocarditis prevalence but higher mortality than industrialised countries. S. aureus bacteraemia is frequently associated with exposure to healthcare settings with MRSA causing a considerable burden of disease. Further studies are required to define setting-specific strategies to reduce mortality from S. aureus bacteraemia, prevent MRSA transmission, and to define the burden of S. aureus disease and emergence of drug resistance throughout the developing world.

Impact of Antibiotic Resistance in Gram‐Negative Bacilli on Empirical and Definitive Antibiotic Therapy

Serious infections with gram-negative pathogens continue to be associated with considerable mortality. Increasing antibiotic resistance in organisms such as Pseudomonas aeruginosa, Acinetobacter baumannii, and Klebsiella pneumoniae is contributing to difficulties with choosing antibiotics to prescribe for these infections. Optimization of therapy against these organisms starts with the initial empirical antibiotic choice. Surveillance data and hospital or unit antibiograms may inform this decision, although individualization of the initial regimen on the basis of prior antibiotic use and prior isolation of resistant pathogens may be more important. Combinations of antibiotics are often required empirically, and "combination antibiograms" may need to be developed for this purpose. Preliminary data suggest that extending the time over which a dose of antipseudomonal beta-lactam antibiotics is infused may improve clinical outcomes; however, this idea remains to be confirmed in randomized trials. The role of direct susceptibility testing in aiding more-rapid initiation of appropriate antibiotic therapy is also being studied. When identification and susceptibility testing is complete, the antibiotic regimen for infections due to gram-negative pathogens can be "fine tuned." On some occasions, this fine tuning necessitates the introduction of "salvage" antibiotics, such as colistin or tigecycline; on others, it necessitates de-escalation and early termination of therapy. The lack of new antibiotic options against gram-negative pathogens underscores the need for optimization of current therapies and prevention of the spread of these organisms.

Impact of the More-Potent Antibiotics Quinupristin-Dalfopristin and Linezolid on Outcome Measure of Patients with Vancomycin-Resistant Enterococcus Bacteremia

The impact of antibiotic resistance on the clinical outcome of patients with vancomycin-resistant Enterococcus (VRE) bacteremia remains unclear. There are limited data comparing patient outcomes during the early era of vancomycin resistance with the period of more-potent antibiotic availability. A retrospective review was conducted of 113 patients with VRE bacteremia at a single institution from August 1993 to September 2005. Patients were assigned to a group on the basis of initial antibiotic choice for treatment of VRE (linezolid, quinupristin-dalfopristin, or combinations of other agents, before newer options were available). Outcome measurements were examined for the initial episode of VRE bacteremia, and multiple logistic regression analysis was performed to compare group outcomes. Overall mortality was 37.2% (42 of 113 patients). VRE bacteremia caused or significantly contributed to death in 29 (69%) of 42 patients. Seventy-one patients were initially treated with linezolid, 20 with quinupristin-dalfopristin, and 22 with combinations of other agents. Univariate analysis indicated significantly more deaths in the quinupristin-dalfopristin group (odds ratio, 5.45; 95% confidence interval, 1.89-15.9) and in the other-agents group (odds ratio, 2.94; 95% confidence interval, 1.09-7.94) than in the linezolid group. However, after adjustment for severity of illness, treatment group was not a significant independent factor. Despite the development of antimicrobial agents with greater potency against VRE, a significant change in clinical outcome was not observed. This suggests that vancomycin resistance does not significantly influence mortality and points to the continued need for prospective, randomized clinical trials.

Comment on: Impact of antibiotic resistance and of adequate empirical antibiotic treatment in the prognosis of patients with Escherichia coli bacteraemia

Comment on: Impact of antibiotic resistance and of adequate empirical antibiotic treatment in the prognosis of patients with Escherichia coli bacteraemia

Impact of antibiotic resistance and of adequate empirical antibiotic treatment in the prognosis of patients with Escherichia coli bacteraemia

Escherichia coli is the most frequent Gram-negative organism causing bacteraemia. There are few data about prognostic factors of bloodstream infections due to E. coli. In particular, the consequences of antibiotic resistance and of adequate empirical antibiotic treatment on outcome remain broadly unknown. We conducted a retrospective cohort study of patients with E. coli bacteraemia between January 1997 and June 2005 to identify any association between antibiotic resistance, adequacy of empirical antibiotic therapy and mortality. Of 663 patients with E. coli bacteraemia, 36 (5.4%) died. Patients with multidrug-resistant (MDR) E. coli bacteraemia had a significantly lower frequency of correct empirical antibiotic treatment than patients with non-MDR E. coli bacteraemia [relative risk (RR) 0.53; 95% confidence interval (CI) 0.48-0.67], and also had a significantly higher mortality (RR 3.31; 95% CI 1.72-6.36). An association between the number of antibiotics to which E. coli was resistant with adequacy of empirical antibiotic (P < 0.001) and with mortality (P < 0.001) was detected. After adjustment for other significant risk factors and confounders, the inadequacy of empirical antibiotic treatment was associated with an increased mortality (adjusted OR 2.98; 95% CI 1.25-7.11). When the adequacy of empirical treatment was excluded from the model, the presence of MDR E. coli in blood cultures was also associated with the prognosis (adjusted OR 3.11; 95% CI 1.3-7.44). In multivariate analysis, other variables associated with the outcome were age, the presence of severe sepsis or shock, Charlson index score and a non-urinary origin of the bacteraemia. Adequacy of empirical antibiotic treatment is an independent risk factor for mortality in patients with E. coli bacteraemia. MDR E. coli bacteraemia had a worse prognosis due, at least in part, to a lower frequency of correct empirical treatment.

Meeting report: Fourth Forum on Respiratory Tract Infections, Sitges, Spain, 8–11 February 2007

Over 420 delegates participated in this, the fourth of a biennial series of scientific meetings, drawing from 30 or more nations and encompassing the specialties of infectious diseases, clinical microbiology, pulmonary and general medicine and Industry inter alia. The 2007 Forum was chaired by Professors Antoni Torres Marti, Giuliana Gialdroni Grassi and Dr Peter Ball and received academic endorsement from the British Society for Antimicrobial Chemotherapy (BSAC), Italian Society for Chemotherapy, Spanish Pulmonology Society, Paul Ehrlich Society and the Société de Pneumologie de Langue Français. The Scientific Programme was scientifically and financially supported by the BSAC and a consortium of pharmaceutical companies. Discussion focused on key contemporary issues in respiratory tract infection (RTI), including the impact of antibiotic resistance on clinical outcomes and the continuing need for antibiotic conservation via evolving guidelines, the challenges of avian influenza, nosocomial RTIs and the emergence of new pathogens, e.g. community-acquired methicillin-resistant Staphylococcus aureus, novel antimicrobial agents, disease definitions (e.g. healthcare-associated pneumonia) and therapeutic assessment criteria, such as patient-reported outcome measures, in improving RTI management. The entire meeting was granted CME recognition (18 sessions) by the European Accreditation Council for continuing medical education.

Rising to the challenge of resistance: a case study-based discussion

Physicians treating patients with lower respiratory tract infections face numerous challenges and treatment decisions. For example, when treating a patient with acute exacerbations of chronic obstructive pulmonary disease (AECOPD), a physician must determine: (1) whether the patient should be hospitalised; (2) the cause of the exacerbation; (3) whether bacterial infection is present; and (4) which antibacterial agent should be used (if antibacterial treatment is required). In this article, the key challenges faced by physicians treating patients with AECOPD are described and illustrated using a case study. The impact of antibiotic resistance and other factors influencing a physician's treatment decisions are discussed, and current evidence and guidelines which should inform these decisions are reviewed.

Clinical impact of antibiotic resistance in respiratory tract infections

Streptococcus pneumoniae is the most common causative pathogen of community-acquired respiratory tract infections. In vitro evidence indicates that S. pneumoniae is increasingly resistant to commonly prescribed antimicrobial agents including the macrolides. The clinical relevance of resistance, however, has not been clearly established. This article reviews the risk factors influencing selection of resistant pneumococci, discusses endpoints used to assess the impact of resistance on clinical outcome, and proposes strategies to minimise the impact of resistance. Evidence demonstrating treatment failures due to macrolide-resistant S. pneumoniae is also reviewed. Increasing rates of resistance among S. pneumoniae present numerous clinical challenges, and require carefully selected treatment strategies to preserve antibacterial efficacy. Antibiotics with a low propensity for stimulating resistance should be chosen wherever possible.

Impact of piperacillin resistance on the outcome of Pseudomonas ventilator-associated pneumonia

The impact of antibiotic resistance on the outcome of infections due to Gram-negative bacilli, especially Pseudomonas, remains highly controversial. STUDY OBJECTIVE, DESIGN, AND PATIENTS: We evaluated the impact of piperacillin resistance on the outcomes of Pseudomonas aeruginosa ventilator-associated pneumonia (VAP) for patients who had received appropriate empiric antibiotics before enrollment in the PNEUMA trial, a multicenter randomized study comparing 8 vs 15 days of antibiotics. Despite similar characteristics at intensive care unit (ICU) admission, patients infected with piperacillin-resistant Pseudomonas strains were more acutely ill at VAP onset and had a higher 28-day mortality rate (37 vs 19%; P = 0.04) than those with piperacillin-susceptible Pseudomonas VAP. Factors associated with 28-day mortality retained by multivariable analysis were: age (OR: 1.07; 95% CI: 1.03-1.12); female gender (OR: 4.00; 95% CI: 1.41-11.11); severe underlying comorbidities (OR: 2.73; 95% CI: 1.02-7.33); and SOFA score (OR: 1.17; 95% CI: 1.03-1.32), but piperacillin resistance did not reach statistical significance (OR: 2.00; 95% CI: 0.72-5.61). The VAP recurrence rates, either superinfection or relapse, and durations of mechanical ventilation and ICU stay did not differ as a function of Pseudomonas-resistance status. For patients with Pseudomonas VAP benefiting from appropriate empiric antibiotics, piperacillin resistance was associated with increased disease severity at VAP onset and higher 28-day crude mortality; however, after controlling for confounders, piperacillin-resistance was no longer significantly associated with 28-day mortality. The VAP recurrence rates and durations of ICU stay and mechanical ventilation did not differ for susceptible and resistant strains.

Impact of Antibiotic Resistance in Hospital Infections

Impact of Antibiotic Resistance in Hospital Infections

Prophylactic antibiotics in surgery

Abstract In the UK, it is estimated that 1 in 10 patients admitted to hospital will develop a health care- associated infection; costing the NHS an estimated £1 billion per annum. Included in these figures are approximately 4% of surgical patients who develop a surgical-site infection, adding an average of 6.5 days to their hospital stay. Prophylactic antibiotics can reduce the risk of surgical-site infections. This contribution discusses the theory behind the use of prophylaxis, including adjuncts to standard intravenous regimens and the impact of antibiotic resistance.

Coagulase-Negative Staphylococcal Sepsis in Neonates

Coagulase-negative staphylococci (CoNS) are the most prevalent pathogens causing late onset sepsis in neonates. They are often multiresistant to antibiotics, and the ability to form biofilm is considered their main virulence determinant. During a 12-year period, we identified 150 neonates having 164 suspected septic episodes with growth of CoNS in blood culture. We examined the relationship between antibiotic resistance, phenotypic biofilm production and genetic determinants for biofilm formation in different CoNS species and their correlation with neonatal inflammatory response. Eighty-five episodes were classified as true sepsis, and 79 episodes of CoNS growth in blood culture were considered contaminations. Sixty-one percent of Staphylococcus epidermidis isolates produced biofilm compared with 26% of CoNS non-epidermidis (P < 0.001). We observed no difference in phenotypic biofilm production or genetic determinants for biofilm formation between invasive isolates and contaminants. C-reactive protein levels as a marker of inflammatory response were higher in CoNS sepsis caused by methicillin and aminoglycoside resistant versus susceptible isolates (P = 0.031). In contrast, there was a significant association between a lower C-reactive protein response and biofilm-positive isolates (P = 0.018). Antibiotic resistance was significantly correlated with biofilm production in S. epidermidis, but not in other CoNS species. CoNS sepsis with biofilm-forming strains was associated with a decreased host inflammatory response, potentially limiting the immune system to counteract the infection. The impact of antibiotic resistance and virulence determinants on clinical outcome of neonatal CoNS sepsis warrants additional clinical studies.

Prophylactic antibiotics in surgery

In the UK, it is estimated that 1 in 10 patients admitted to hospital will develop a health care- associated infection; costing the NHS an estimated £1 billion per annum. Included in these figures are approximately 4% of surgical patients who develop a surgical-site infection, adding an average of 6.5 days to their hospital stay. Prophylactic antibiotics can reduce the risk of surgical-site infections. This contribution discusses the theory behind the use of prophylaxis, including adjuncts to standard intravenous regimens and the impact of antibiotic resistance.

Impact of Antibiotic Resistance on the Treatment of Sepsis

Antibiotics are essential to the treatment of bacterial sepsis as they reduce the bacterial burden. The impact of bacterial resistance has recently been studied and found to be important in a range of conditions. Resistance to antibiotics can be defined genotypically, phenotypically and clinically through pharmacokinetic/pharmacodynamic studies and their correlations with clinical outcomes. Although the kinetics of antibiotics has been shown to be favourably altered in sepsis, a range of studies in sepsis has revealed that for most pathogens resistance contributes to significant increases in mortality. This has been clearly demonstrated in bacteraemia, including community- and hospital-acquired infection, and with bacteraemia caused by vancomycin-resistant enterococci, methicillin-resistant staphylococci and extended-spectrum producing Gram-negative bacteria. Significant mortality increases have also been seen with ventilator-associated pneumonia and serious infections requiring admission to intensive care. Gentotypic and phenotypic resistance in coagulase-negative staphylococci causing bacteraemia, and in invasive pneumococcal disease has not shown differences in mortality. In the latter case, dosage regimens have to date been adequate to overcome laboratory-defined resistance. Early indications are that de-escalating therapy from broad-spectrum initial coverage after results of cultures and susceptibility tests become available does not jeopardize outcomes, and further prospective studies are warranted. There is now convincing evidence that broad-spectrum initial therapy to cover the likely pathogens and their resistances pending culture results is mandatory in sepsis to minimize adverse outcomes.

Update on community-acquired pneumonia: impact of antibiotic resistance on clinical outcomes

Update on community-acquired pneumonia: impact of antibiotic resistance on clinical outcomes

Update on community-acquired pneumonia: impact of antibiotic resistance on clinical outcomes.

In contrast to the rapid expansion in the number of published studies reporting the increasing rate of antimicrobial drug resistance among common respiratory pathogens, there remain few controlled studies examining the impact of these trends on clinical outcomes. Those studies that are published are hampered by small sample sizes, biases inherent in observational designs, and the relative infrequency of isolates showing high-level resistance, particularly high-level beta-lactam resistance among clinical isolates of Streptococcus pneumoniae. This update summarizes recent published studies addressing the impact of drug resistance on outcomes for lower respiratory tract infections. The majority of these studies are retrospective cohort studies, focusing on the impact of beta-lactam-resistant pneumococcal infections in patients with community-acquired pneumonia. These studies support the conclusion that current levels of pneumococcal drug resistance do not result in clinical treatment failures for patients with community-acquired pneumonia. However, as patterns of drug resistance evolve, future studies will be needed to address the continued appropriateness of current empirical treatment guidelines for these patients.

Management of Antimicrobials in Infectious Diseases: Impact of Antibiotic Resistance

Management of Antimicrobials in Infectious Diseases: Impact of Antibiotic Resistance