Acinetobacter spp. as nosocomial pathogens: microbiological, clinical, and epidemiological features.

INTRODUCTION .......................................................................................................................................................149 TAXONOMY ...............................................................................................................................................................149 Historical Features .................................................................................................................................................149 Current Taxonomic Status ....................................................................................................................................149 Delineation of Species ............................................................................................................................................149 Species of Clinical Importance .............................................................................................................................150 LABORATORY IDENTIFICATION.........................................................................................................................150 Isolation from Clinical Specimens .......................................................................................................................150 Morphological, Cultural, and Metabolic Characteristics .................................................................................151 Species Identification .............................................................................................................................................151 NOSOCOMIAL INFECTIONS CAUSED BY ACINETOBACTER SPP. .............................................................152 Overview ...................................................................................................................................................................152 Respiratory Infection..............................................................................................................................................152 Bacteremia ...............................................................................................................................................................153 Meningitis ................................................................................................................................................................153 Urinary Tract Infection..........................................................................................................................................154 Other Miscellaneous Infections ............................................................................................................................154 PATHOGENESIS OF ACINETOBACTER INFECTIONS.....................................................................................154 Predisposing Factors ..............................................................................................................................................154 Virulence of Acinetobacter spp. ..............................................................................................................................154 EPIDEMIOLOGY.......................................................................................................................................................155 Human Carriage .....................................................................................................................................................155 Persistence in the Hospital Environment............................................................................................................155 TYPING SYSTEMS....................................................................................................................................................156 Biotyping ..................................................................................................................................................................156 Antibiograms ...........................................................................................................................................................156 Serotyping ................................................................................................................................................................156 Phage Typing ...........................................................................................................................................................157 Bacteriocin Typing..................................................................................................................................................157 Protein Profiles .......................................................................................................................................................157 Multilocus Enzyme Electrophoretic Typing ........................................................................................................157 Plasmid Profiles ......................................................................................................................................................157 Analysis by Pulsed-Field Gel Electrophoresis ....................................................................................................157 Ribotyping................................................................................................................................................................157 PCR-Based Methods...............................................................................................................................................158 CLINICAL ANTIBIOTIC RESISTANCE................................................................................................................158 BIOCHEMICAL AND GENETIC MECHANISMS OF ANTIBIOTIC RESISTANCE.....................................158 Genetics of Resistance............................................................................................................................................158 b-Lactams ................................................................................................................................................................159 Aminoglycosides ......................................................................................................................................................159 Quinolones ...............................................................................................................................................................160 Other Antibiotics.....................................................................................................................................................160 THERAPY OF ACINETOBACTER INFECTIONS .................................................................................................160 CONCLUSIONS .........................................................................................................................................................160 ACKNOWLEDGMENTS ...........................................................................................................................................161 REFERENCES ............................................................................................................................................................161