Intensive Care Med (2007) 33:143–147 DOI 10.1007/s00134-006-0435-8 BRIEF REPORT Celia García Estibaliz Ugalde Idoia Monteagudo Ana Saez Jesús Agüero Luis Martinez-Martinez Eduardo Miñambres Isolation of Mycoplasma hominis in critically ill patients with pulmonary infections: clinical and microbiological analysis in an intensive care unit Received: 2 June 2006 Accepted: 22 September 2006 Published online: 8 November 2006 © Springer-Verlag 2006 C. García · E. Ugalde · I. Monteagudo · A. Saez · J. Agüero · L. Martinez-Martinez University Hospital Marqués de Valdecilla, Microbiology Service, Santander, Spain J. Agüero · L. Martinez-Martinez University of Cantabria, Department of Molecular Biology, Santander, Spain E. Miñambres (✉) Hospital Universitario Marqués de Valdecilla, Intensive Care Service, Avda Valdecillas/n, 39008 Santander, Spain e-mail: eminambres@yahoo.es Tel.: +34-942-203304 Fax: +34-942-203543 Abstract Objective: Mycoplasma hominis is a well recognized extra- genital pathogen. However, it is an uncommon cause of respiratory infec- tions in critically ill patients admitted to the intensive care unit (ICU). De- sign and setting: Prospective clinical investigation in a 21-bed ICU in a university hospital. Patients: Seven patients requiring intensive care who developed a ICU-acquired pneumonia in which M. hominis was recovered from bronchoalveolar lavage and pleural fluid cultures. Interventions: M. hominis was isolated in all patients by use of conventional bacteriological cultures. All strains were identified by 16S rRNA gene sequencing analysis. Patients’ charts were reviewed for each case of infection. Results: Seven strains of M. hominis were isolated during a 4-year period. All of these isolates were recovered from adult men admitted to the ICU and all had clinical signs of pneumonia. In three patients treatment for M. hominis with quinolones was asso- ciated with a good clinical response. Conclusion: Suspicion of M. homi- nis pneumonia must be heightened particularly in critically ill patients. Therefore an understanding of the microbiology of this organism is essential to successfully treat patients with these infections that are not ordinarily covered with standard antibiotic therapy. Keywords Mycoplasma hominis · Pneumonia · Intensive care unit Introduction Patients admitted into intensive care units (ICUs) are at a great risk for acquiring nosocomial infections due to their critical conditions and weakened immune sys- tem [1]. Ventilator-associated pneumonia (VAP) is the most frequent nosocomial infection in the ICU and occurs in roughly 25% of patients requiring mechanical ventilation (MV) for more than 48 h [2, 3]. Mycoplasma hominis is a commensal inhabitant of the lower urogenital tract in many sexually active adult men and women [4]. However, it may also cause localized extragenital disease. Host predisposing factors such as immunosuppression, malignancy, trauma, and complications related to uro- genital manipulations or surgery are considered to be associated with extragenital mycoplasma infections [5]. The recognition of infections by Mycoplasma species in critically ill patients is important because β-lactam and aminoglycoside antibiotics, which are usually used in empirical antibiotic therapy, are not effective against these organisms. Pneumonia caused by M. hominis is very rare, but since the true incidence of infections caused by this pathogen is unknown, its real importance may be underestimated. Recognition of the morphological characteristics of mycoplasmas on bacteriological culture media may increase the recovery of these organisms in atypical clinical settings [6]. Here we describe the clinical and microbiological features of seven isolates of M. hominis in critically ill patients who acquired pneumonia during their hospitalization to the ICU. The case of one of these patients has been previously reported [7].