Clinical resistance encountered in the respiratory surveillance program (RESP) study: a review of the implications for the treatment of community-acquired respiratory tract infections

What is the role of antimicrobial stewardship in improving outcomes of patients with CAP?

Community-acquired pneumonia (CAP) is one of the most common infectious diagnoses encountered in clinical practice and one of the leading causes of death in the United States. Adherence to antibiotic treatment guidelines is inconsistent and the erroneous diagnosis of CAP and misuse of antibiotics is prevalent in both inpatients and outpatients. This review summarizes interventions that may be promoted by antimicrobial stewardship programs to improve outcomes for patients with CAP.

Tigecycline

New antimicrobial agents are urgently needed for clinical use due to the increasing prevalence and spread of multidrug-resistant bacteria that are commonly responsible for serious and life-threatening diseases. The need to develop new agents that effectively overcome existing mechanisms of resistance displayed by bacteria resistant to currently available drugs has become paramount. Tigecycline, the first in a new class of antimicrobials, the glycylcyclines, is an analogue of minocycline with additional properties that negate most mechanisms mediating resistance to the tetracyclines. In vitro testing has revealed that tigecycline has activity against vancomycin-resistant enterococci, methicillin-resistant Staphylococcus aureus, penicillin-resistant Streptococcus pneumoniae and many species of multidrug-resistant Gram-negative bacteria, although resistance to tigecycline by Pseudomonas aeruginosa and reduced susceptibility among Proteus species do occur. Tigecycline is being evaluated in multicentre Phase III clinical trials for therapy of many serious and life-threatening infections in which multidrug-resistant bacterial organisms may be found. Tigecycline appears to hold promise as a novel expanded spectrum antibiotic.

In vitro activity of gemifloxacin and contemporary oral antimicrobial agents against 27,247 Gram-positive and Gram-negative aerobic isolates: a global surveillance study

This study was a multi-centre, multi-country surveillance of 27247 Gram-positive and Gram-negative isolates collected from 131 study centres in 44 countries from 1997 to 2000. MICs of gemifloxacin were compared with penicillin, amoxicillin-clavulanic acid, cefuroxime, azithromycin, clarithromycin, trimethoprim-sulphamethoxazole, ciprofloxacin, grepafloxacin and levofloxacin by broth microdilution. Penicillin resistance in Streptococcus pneumoniae was extremely high in the Middle East (65.6%), Africa (64.0%) and Asia (60.4%) and lower in North America (40.3%), Europe (36.9%) and the South Pacific (31.8%). Macrolide resistance in S. pneumoniae was highest in Asia (51.7%) but varied widely between laboratories in Europe (26.0%), North America (21.6%), the Middle East (13.7%), the South Pacific (10.6%) and Africa (10.0%). All the study quinolones were highly active against penicillin-resistant and macrolide-resistant S. pneumoniae. Overall, gemifloxacin had the lowest MIC(90) at 0.06 mg/l with MICs 4-64-fold lower than ciprofloxacin, levofloxacin and grepafloxacin against S. pneumoniae. Gemifloxacin MICs were more potent than grepafloxacin > levoflaxacin > ciproflaxin against the Gram-positive aerobes and shared comparable Gram-negative activity with ciprofloxacin and levofloxacin.

Antibacterials: are the new entries enough to deal with the emerging resistance problems?

Fifty years of making analogs based on less than ten antibacterial scaffolds has resulted in the development and marketing of over 100 antibacterial agents but, with the exception of the oxazolidinone core, no new scaffolds have emerged in the past 30 years to address emerging resistance problems. As the support for antibacterial research shifts away from large pharmaceutical companies, a wave of biotechnology companies have pursued a diverse choice of targets resulting in several novel classes of agent in late-stage development. Although critical for certain resistance niche needs, these agents are unlikely to provide the solution to the requirement for a major novel scaffold class of antibacterials.

Antibiotic use in Hispanic households, New York city

Trained interviewers visited 631 inner city households to determine community prevalence and predictors of antibiotic use. Infectious disease symptoms were reported in 911 (33.2%) of 2,743 household members in the previous 30 days: medical attention was sought by 441 (48.4%) of 911 persons, and 354 (38.9%) of 911 took antibiotics for symptoms. Reported symptoms were respiratory (68.9%), gastrointestinal (15.3%), fever (12.8%), and skin infection (2.8%). Medical attention was sought significantly more often among those with chronic illness, those born in the United States, and those with fever, runny nose, or skin infections (all p<0.05). Antibiotics were taken significantly more often among those with poor health, those who spent more time at home, and those with fever and respiratory symptoms. Interventions to promote judicious use of antibiotics must include clinicians and the public, and for the Hispanic population such interventions must also be culturally relevant and provided in Spanish.

Acute respiratory infections control in the context of the IMCI strategy in the Americas

Acute respiratory infections (ARI) are an important cause of morbidiyty and mortality in children all over the World, particularly in developing countries. Contrasts in mortality can be observed among the countries in America, and also within the countries. Contrasts are also observed in morbidity, associated with differences in nutritional status, absence of breast-feeding and characteristics of care given for ill chidren. Parents perception of disease, patterns and habits of care administered to child during the illness, level of concern about decision to seek assistence, manner in wich care is sought and extent to wich recommendations are followed have great influence in the course and outcome of the disease. Bacterial resistance to antibiotics is an increasing problem in America, with an average of 26,1% resistance of Streptococcus pneumonia to penicilin. Antibiotics are frequently used in irrational way, and up to 70% of ARI receive antibiotics unnecessarily. Controlling IRA has become a priority. Preventive interventions with vaccines, specially current conjugate vaccines against Haemophilus influenzae and Streptococcus pneumoniae, and standardized case management, as proposed by Integrated Management of Childhood Ilness (IMCI) seems to be the most important steps for this public health problem.

Gatifloxacin phase IV surveillance trial (TeqCES study) utilizing 5000 primary care physician practices: report of pathogens isolated and susceptibility patterns in community-acquired respiratory tract infections

Recently FDA-approved fluoroquinolones like gatifloxacin possess enhanced activity against Gram-positive pathogens such as Streptococcus pneumoniae. However, experience with adverse events among previously used fluoroquinolones has led to expanded post-marketing investigations of clinical efficacy and safety. An open-label gatifloxacin trial was initiated in early 2000, using 2795 (>15000 enrolled cases) primary care providers for treatment of community-acquired respiratory tract infections (CARTI) such as community-acquired pneumonia (CAP), acute bacterial exacerbation of chronic bronchitis (ABECB), acute sinusitis. Microbiology specimens and sputum slides were referred to a reference laboratory, pathogens identified and reference antimicrobial susceptibility tests performed. Results were classified by infection site, geographic census region and patient profile/demographics. The most frequent pathogens were: for CAP (n = 384)-S. pneumoniae (37%) > Hemophilus influenzae (31%) > Moraxella catarrhalis (13%); for ABECB (528)-H. influenzae (37%) > M. catarrhalis (26%) > S. pneumoniae (17%); and for sinusitis (2691)-M. catarrhalis (29%) > H. influenzae (24%) > S. pneumoniae (17%). H. parainfluenzae (ABECB) and S. aureus (sinusitis) were also commonly isolated. CAP S. pneumoniae isolates had significantly less high-level resistance (5% at > or =2 micro g/ml) than those isolates from ABECB or sinusitis (13-15%). United States census zone differences in S. pneumoniae resistance were identified (greatest in West or East South Central, South Atlantic). S. pneumoniae macrolide resistance was high (23-33%) and H. influenzae clarithromycin susceptibility was only 56-62%. beta-lactamase rates in H. influenzae and M. catarrhalis were 21-29% and 88-92%, respectively. Only one S. pneumoniae was not susceptible to gatifloxacin, and this new fluoroquinolone was fourfold more potent than levofloxacin (MIC(50,) 0.25 vs. 1 micro g/ml). This Phase IV surveillance trial (TeqCES) confirmed the clinical importance of S. pneumoniae, H. influenzae and M. catarrhalis in CARTI, and high fluoroquinolone potency/spectrum (>97% susceptible). beta-lactams and macrolides continue to be compromised by increasing resistances in pathogens isolated in these monitored primary care settings.