Archive for March 22, 2013

Legionella: macrolides or quinolones?

Clin Microbiol Infect. 2006 May;12 Suppl 3:25-30.

Pedro-Botet L, Yu VL.


Infectious Diseases Unit, Hospital Universitari Germans Trias i Pujol, Universitat Autonoma de Barcelona, Barcelona, Spain.


Following the first outbreaks of legionnaire’s disease, erythromycin emerged as the treatment of choice without the foundation of rigorous clinical trials. The number of therapeutic failures with erythromycin, as well as the side-effects and drug interactions, led to the consideration of other drugs such as the new macrolides and quinolones for the treatment of legionnaire’s disease in the 1990s. In this article, 19 studies in in-vitro intracellular models and seven animal studies that compared macrolides to quinolones were reviewed. Quinolones were found to have greater activity in intracellular models and improved efficacy in animal models compared with macrolides. No randomised trials comparing the clinical efficacy of the new macrolides and new quinolones have ever been performed. Three observational studies totalling 458 patients with legionnaire’s disease have compared the clinical efficacy of macrolides (not including azithromycin) and quinolones (mainly levofloxacin). The results suggested that quinolones may produce a superior clinical response compared with the macrolides (erythromycin and clarithromycin) with regard to defervescence, complications, and length of hospital stay. Little data exist for direct comparison of quinolones and azithromycin.


March 22, 2013 at 8:32 am

Diagnostic tests for agents of community-acquired pneumonia.

Clin Infect Dis. 2011 May;52 Suppl 4:S296-304.

Bartlett JG.


School of Medicine, JohnsHopkinsUniversity, Baltimore, Maryland21205, USA.


Lower respiratory infections are the major cause of death due to infectious disease in the United States and worldwide. Most forms of community-acquired pneumonia (CAP) are treatable, and there is consensus that the selection of antimicrobial agents is notably simplified if the pathogen is defined. The rich history of CAP studies in the prepenicillin era showed that an etiologic diagnosis was established in >90% of cases, but the 2009 data from Medicare indicate that a probable pathogen is now detected in <10% according to a review of the records of >17,000 patients hospitalized with CAP. This review addresses the issue of the state of the art of microbiological studies of CAP in terms of the realities of current-day practice. Unfortunately, the desire for better data to achieve pathogen-directed treatment clashes with a multitude of harsh realities, including cost, Centers for Medicare and Medicaid Services (CMS) requirements for antibiotics to be administered within 6 h of disease onset, guidelines that discourage any microbiological studies in most cases, belief in empiricism that is well supported by at least 1 prospective study, the decline of microbiological analysis standards in most laboratories, and the devastating impact of the Clinical Laboratory Improvement Amendments (CLIA) regulations that led to the demise of “the house staff laboratory” and the distancing of microbiological analysis from the site of care. Microbiological principles are reviewed, with emphasis on specimen source, pathogenic potential of isolates, concentrations, impact of antecedent antibiotics, and the “Washington criteria” for expectorated sputum. The recommendation is that the high-quality microbiological analysis that is still achieved in some places should be retained but that to advance the field on the basis of the contemporary realities, two goals should be adopted: First is the broad use of antigen tests for Streptococcus pneumoniae and Legionella pneumophila with interpretation by clinical staff under the CLIA waiver for low-complexity tests. The second and more ambitious recommendation is the adoption of molecular techniques, with particular emphasis on nucleic acid detection, which is rapid and sensitive and has already been developed for virtually all recognized pulmonary pathogens. This may be the ultimate solution for many laboratories, and it is likely to have selected use.


March 22, 2013 at 8:27 am

Infectious Diseases Society of America/American Thoracic Society consensus guidelines on the management of community-acquired pneumonia in adults. 2007

Clin Infect Dis. 2007 Mar 1;44 Suppl 2:S27-72.

Mandell LA, Wunderink RG, Anzueto A, Bartlett JG, Campbell GD, Dean NC, Dowell SF, File TM Jr, Musher DM, Niederman MS, Torres A, Whitney CG; Infectious Diseases Society of America; American Thoracic Society.


McMasterUniversityMedicalSchool, Hamilton, Ontario, Canada.


March 22, 2013 at 8:23 am


N Engl J Med. 1997 Sep 4;337(10):682-7.

Stout JE, Yu VL.


VeteransAffairsMedicalCenter and the University of Pittsburgh, PA15240, USA.

Legionnaires’ disease was first recognized during an outbreak of pneumonia involving delegates to the 1976 American Legion convention at a Philadelphia hotel. Full appreciation of its role other than as an exotic pathogen has only come in the past several years. As diagnostic methods have improved and epidemiologic understanding of its reservoir has been exploited, legionella has been found to be a common cause of community-acquired and nosocomial pneumonia. Many excellent reviews have been published,1-4 so this review will focus on newer findings….


March 22, 2013 at 8:20 am

An unprecedented outbreak investigation for nosocomial and community-acquired legionellosis in Hong Kong.

Chin Med J (Engl). 2012 Dec;125(23):4283-90.

Cheng VC, Wong SS, Chen JH, Chan JF, To KK, Poon RW, Wong SC, Chan KH, Tai JW, Ho PL, Tsang TH, Yuen KY.


Department of Microbiology, Queen Mary Hospital, Hong Kong, China.



The environmental sources associated with community-acquired or nosocomial legionellosis were not always detectable in the mainland of China and Hong Kong, China. The objective of this study was to illustrate the control measures implemented for nosocomial and community outbreaks of legionellosis, and to understand the environmental distribution of legionella in the water system in Hong Kong, China.


We investigated the environmental sources of two cases of legionellosis acquired in the hospital and the community by extensive outbreak investigation and sampling of the potable water system using culture and genetic testing at the respective premises.


The diagnosis of nosocomial legionellosis was suspected in a patient presenting with nosocomial pneumonia not responsive to multiple beta-lactam antibiotics with subsequent confirmation by Legionella pneumophila serogroup 1 antigenuria. High counts of Legionella pneumophila were detected in the potable water supply of the 70-year-old hospital building. Another patient on continuous ambulatory peritoneal dialysis presenting with acute community-acquired pneumonia and severe diarrhoea was positive for Legionella pneumophila serogroup 1 by polymerase chain reaction (PCR) testing on both sputum and nasopharyngeal aspirate despite negative antigenuria. Paradoxically the source of the second case was traced to the water system of a newly commissioned office building complex. No further cases were detected after shock hyperchlorination with or without superheating of the water systems. Subsequent legionella counts were drastically reduced. Point-of-care infection control by off-boiled or sterile water for mouth care and installation of water filter for showers in the hospital wards for immunocompromised patients was instituted. Territory wide investigation of the community potable water supply showed that 22.1% of the household water supply was positive at a mean legionella count of 108.56 CFU/ml (range 0.10 to 639.30 CFU/ml).


Potable water systems are open systems which are inevitably colonized by bacterial biofilms containing Legionella species. High bacterial counts related to human cases may occur with stagnation of flow in both old or newly commissioned buildings. Vigilance against legionellosis is important in healthcare settings with dense population of highly susceptible hosts.


March 22, 2013 at 8:12 am


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