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Advancements in microbial identification occur increasingly faster as more laboratories explore, refine and extend the use of mass spectrometry in the field of microbiology. Areas covered: This review covers the latest knowledge found in the literature for quick identification of various classes of bacterial pathogens known to cause human infection by the use of MALDI-TOF MS technology. Except for identification of bacterial strains, more researchers try to 'battle time' in favor of the patient. These novel approaches to identify bacteria directly from clinical samples and even determine antibiotic resistance are extensively revised and discussed. Expert commentary: Mass spectrometry is the future of bacterial identification and creates a new era in modern microbiology. Its incorporation in routine practice seems to be not too far, providing a valuable alternative, especially in terms of time, to conventional techniques. If the technology further advances, quick bacterial identification and probable identification of common antibiotic resistance might guide patient decision-making regarding bacterial infectious diseases in the near future.

Coxiella burnetii is a Gram-negative, gamma-proteobacteria with nearly worldwide distribution, and it is the pathogenic agent of Q-fever in man. It is an obligate intracellular parasite that is highly adapted to reside within the eukaryotic phagolysosome. In fact, it is the only known intracellular bacterium that manages to survive and replicate within a fully formed, acidic phagolysosome. C. burnetti possesses a functional Type 4 Secretion System (T4SS), similar to the Dot/Icm system of Legionella pneumophila. Up to date there have been no reports for the effector molecules secreted by Coxiella's T4SS. These are speculated to have quite different roles than the effectors of other intracellular pathogens, since there is no need for phagosomal arrest or escape in the case of Coxiella. In this study, we have investigated the cytoplasm of Vero cells infected with C. burnetti strain Nine Mile Phase II. We have identified by mass spectrometry (ESI-MS/MS) several C. burnetti proteins that bear typical characteristics of effector molecules. Most of the identified proteins were also very alkaline, something which is supportive for a protective strategy that has evolved in this bizarre pathogen against acidic environments.

The present article is a study of the in vitro susceptibility of eight Greek Coxiella burnetii isolates, derived from patients with acute Q fever, and two reference strains of Coxiella burnetii to tigecycline. The bacteriostatic activity of tigecycline was compared with those of six other antibiotics using a shell vial assay. The MICs of the examined antibiotics were as follows: tigecycline ranged from 0.25 to 0.5 g/ml; doxycycline, trovafloxacin, and ofloxacin ranged from 1 to 2 g/ml; linezolid and clarithromycin ranged from 2 to 4 g/ml; and ciprofloxacin ranged from 4 to 8 g/ml. Tigecycline was effective in inhibiting the infection of Vero cells by C. burnetii. No bactericidal activity was observed against C. burnetii at 4 g/ml.