Cheston B. Cunha

Middle East respiratory syndrome (MERS): a new zoonotic viral pneumonia.

Coronaviruses have traditionally been associated with mild upper respiratory tract infections throughout the world. In the fall of 2002, a new coronavirus emerged in in Asia causing severe viral pneumonia, i.e., severe acute respiratory syndrome (SARS). Nearly a decade following the SARS epidemic, a new coronavirus causing severe viral pneumonia has emerged, i.e., middle east respiratory syndrome (MERS). Since the initial case of MERS-CoV occurred in June of 2012 in Saudi Arabia there have been 688 confirmed cases and 282 deaths in 20 countries. Although both SARS and MERS are caused by coronaviruses, SARS was characterized by efficient human transmission and relatively low mortality rate. In contrast, MERS is relatively inefficiently transmitted to humans but has a high mortality rate. Given the potential overlap in presentation and manifestation, it is important to understand the clinical and epidemiologic differences between MERS, SARS and influenza.

Distinguishing characteristics between pandemic 2009-2010 influenza A (H1N1) and other viruses in patients hospitalized with respiratory illness.

Background Differences in clinical presentation and outcomes among patients infected with pandemic 2009 influenza A H1N1 (pH1N1) compared to other respiratory viruses have not been fully elucidated. Methodology/Principal Findings A retrospective study was performed of all hospitalized patients at the peak of the pH1N1 season in whom a single respiratory virus was detected by a molecular assay targeting 18 viruses/subtypes (RVP, Luminex xTAG). Fifty-two percent (615/1192) of patients from October, 2009 to December, 2009 had a single respiratory virus (291 pH1N1; 207 rhinovirus; 45 RSV A/B; 37 parainfluenza; 27 adenovirus; 6 coronavirus; and 2 metapneumovirus). No seasonal influenza A or B was detected. Individuals with pH1N1, compared to other viruses, were more likely to present with fever (92% & 70%), cough (92% & 86%), sore throat (32% & 16%), nausea (31% & 8%), vomiting (39% & 30%), abdominal pain (14% & 7%), and a lower white blood count (8,500/L & 13,600/L, all p-values<0.05). In patients with cough and gastrointestinal complaints, the presence of subjective fever/chills independently raised the likelihood of pH1N1 (OR 10). Fifty-five percent (336/615) of our cohort received antibacterial agents, 63% (385/615) received oseltamivir, and 41% (252/615) received steroids. The mortality rate of our cohort was 1% (7/615) and was higher in individuals with pH1N1 compared to other viruses (2.1% & 0.3%, respectively; p = 0.04). Conclusions/Significance During the peak pandemic 2009–2010 influenza season in Rhode Island, nearly half of patients admitted with influenza-like symptoms had respiratory viruses other than influenza A. A high proportion of patients were treated with antibiotics and pH1N1 infection had higher mortality compared to other respiratory viruses.

Antimicrobial stewardship programs (ASPs): the devil is in the details.

Infectious disease clinicians traditionally have had the leadership role in recommending appropriate and optimal antibiotic use of antibiotics in hospitals. This judicious and optimized use of antimicrobial agents is the central principle of antimicrobial stewardship. In addition to increased awareness among infectious disease experts, antimicrobial stewardship has become a national priority. Recently, the US Food and Drug Administration (FDA) promoted antimicrobial stewardship by creating incentives to encourage new anti-infective research. The Infectious Diseases of Society of America (IDSA) launched the campaign “Bad Bugs, No Drugs” to plead for the development of new systemic antibiotics.1 While efforts at stewardship are important in their own right, the relative paucity of new agents and the spread of multi-drug resistant organisms have further emphasized the need for antimicrobial stewardship programs (ASPs) in order to preserve the antimicrobial agents that are currently available.

Antibiotic Prescribing for Urinary Tract Infections in the Emergency Department Based on Local Antibiotic Resistance Patterns: Implications for Antimicrobial Stewardship

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Fever of Unknown Origin: A Clinical Approach

Fevers of unknown origin remain one of the most difficult diagnostic challenges in medicine. Because fever of unknown origin may be caused by over 200 malignant/neoplastic, infectious, rheumatic/inflammatory, and miscellaneous disorders, clinicians often order non-clue-based imaging and specific testing early in the fever of unknown origin work-up, which may be inefficient/misleading. Unlike most other fever-of-unknown-origin reviews, this article presents a clinical approach. Characteristic history and physical examination findings together with key nonspecific test abnormalities are the basis for a focused clue-directed fever of unknown origin work-up.

Legionnaire’s Disease and its Mimics: A Clinical Perspective

Whenever the cardinal manifestations of a disorder occur in similar disorders, there is potential for a disease mimic. Legionnaires disease has protean manifestations and has the potential to mimic or be mimicked by other community acquired pneumonias (CAPs). In CAPs caused by other than Legionella species, the more characteristic features in common with legionnaires disease the more difficult the diagnostic conundrum. In hospitalized adults with CAP, legionnaires disease may mimic influenza or other viral pneumonias. Of the bacterial causes of CAP, psittacosis and Q fever, but not tularemia, are frequent mimics of legionnaires disease.

The First Atypical Pneumonia: The History of the Discovery of Mycoplasma pneumoniae

The subject of atypical pneumonias is of great medical and historical interest to modern physicians. Although these diseases have no doubt affected humans throughout our history, it is not until the mid-twentieth century that physicians first began to differentiate certain atypical pulmonary infectious processes from typical pneumonia. Physicians at the time were unclear as to the precise etiology of these infections. As time progressed and study of these organisms continued, physicians were better able to identify the causative agent and devise tests with which to detect the disease. This article focuses on the description and ultimate identification of Mycoplasma pneumoniae.

Antimicrobial Therapy for Legionnaire’s Disease: Antibiotic Stewardship Implications

Legionnaires disease is a common cause of community-acquired pneumonia (CAP). Although no single clinical feature is diagnostic, if characteristic extrapulmonary findings are present a presumptive clinical syndromic diagnosis is possible. Depending on geographic location, season, and physician awareness, Legionnaires disease may be included in the differential diagnosis of CAP. Some antibiotics effective against Legionella sp are also effective in treating the typical bacterial causes of CAP. From an antimicrobial stewardship program (ASP) perspective, monotherapy is preferred to double-drug therapy. From an ASP and pharmacoeconomic standpoint, monotherapy with doxycycline or a respiratory quinolone provides optimal cost effective therapy.

Legionnaire's Disease Since Philadelphia: Lessons Learned and Continued Progress

Legionnaires disease has been recognized as a cause of severe community-acquired pneumonia (CAP). Legionnaires disease has characteristic extrapulmonary findings that are the basis for a presumptive clinical diagnosis. The widespread use of Legionella culture, sputum DFA, serology, urinary antigen testing, and polymerase chain reaction have allowed earlier diagnosis of Legionnaires disease. Excluding common source outbreaks, CAP caused by Legionnaires disease is manifested as sporadic cases. In contrast, nosocomial Legionnaires disease occurs in clusters or outbreaks from common Legionella species-contaminated water sources. Improved diagnostic tests have permitted accurate diagnosis. Bacterial coinfections with Legionnaires disease are uncommon, but when present, are most often associated with bacteremia pneumococcal pneumonia.

Legionnaire's Disease: A Clinical Diagnostic Approach

Legionnaires disease is a nonzoonotic atypical pneumonia caused by Legionella sp that occurs sporadically or in outbreaks. Legionnaires disease pneumonia is accompanied by several extrapulmonary clinical and laboratory findings. Rather than testing all pneumonias for Legionnaires disease, the clinical challenge is to recognize the diagnostic significance of Legionnaires diseases. The pretest probability of Legionnaires disease is increased if several characteristic extrapulmonary findings are present. Similarly, if certain key findings are absent, Legionnaires disease may be eliminated from further diagnostic consideration. If characteristic clinical findings are present, then specific tests should be ordered to confirm or rule out Legionnaires disease.