Acinetobacter bacteremia in the tropics.

In this issue of Clinical Infectious Diseases, Siau and colent temperatures, glucose oxidation, and assimilation of various carbon sources as suggested by Bouvet and Grimont [8], still do leagues [1] report on the epidemiology and clinical features of acinetobacter bacteremia observed in a 1,350-bed tertiary care not distinguish A. baumannii from Acinetobacter DNA group 3 and DNA group 13TU. A simple test to distinguish A. baumanteaching hospital during the summer season in Hong Kong. This rather small series includes 16 cases of bacteremia due nii from other Acinetobacter species is urgently needed. What else is remarkable about the study of Siau et al.? In to Acinetobacter baumannii and two cases of bacteremia due to Acinetobacter lwoffii. However, it is one of the few studies other recent reports, primarily from Europe and the United States, A. baumannii bacteremia was observed mainly in the that includes identification of Acinetobacter species according to the current taxonomy [2, 3]. intensive care unit (ICU) and often ran a fulminant course with a crude mortality rate as high as 52% [6, 9, 10]. In the study by It might have been more prudent still if Siau et al. had excluded the two cases of A. lwoffii bacteremia, thus making Siau et al., in contrast, most cases of A. baumannii bacteremia occurred in the general ward, and only four (22%) of 18 cases it easier to compare their findings with the presentation of A. baumannii bacteremia in other recent reports [4–6]. A. bauwere observed in the ICU setting. The investigators did not provide clinical details on the cases of A. baumannii bactermannii is the most important species and usually predominates among clinical Acinetobacter isolates. It has been well estabemia. In particular, the rates of clinical sepsis and end-organ failure were not reported, but it may be concluded from the lished that the epidemiology and clinical features of A. baumannii bacteremia are distinct from those of bacteremia caused by low mortality rate of 5.6% (one of 18 patients died) that the clinical course was generally rather benign. Acinetobacter species other than A. baumannii, such as A. lwoffii and Acinetobacter johnsonii [4–6]. Therefore, it may no Cross-transmission between patients that was demonstrated with modern epidemiological typing methods such as plasmid longer be appropriate to use the broad term acinetobacter bacteremia as one would not use the term staphylococcal bacterprofiling, ribotyping, randomly amplified polymorphic DNA PCR analysis, and pulsed-field gel electrophoresis of genomic emia in a similar context. DNA was a major finding associated with A. baumannii infection in previous studies [4, 11]. Siau and colleagues reported See article by Siau et al. on pages 26–30. that they previously determined that Acinetobacter species are endemic at Queen Mary Hospital in Hong Kong. Unfortunately, The taxonomy of the genus Acinetobacter is still confusing they did not provide any data on the epidemiology of A. bausince there are at least 19 DNA groups identified by DNA mannii in their hospital during the study period, and possible hybridization studies; seven of these groups have been assigned strain relatedness among A. baumannii isolates from blood on bacterial names. Further insight into this complex topic can be the basis of one of the above-mentioned techniques was not obtained from a recent article that includes an in-depth review assessed. No conclusions can therefore be drawn from their of the current taxonomy of the genus [2]. current study with regard to the rate of cross-transmission of The need to properly identify Acinetobacter isolates recovA. baumannii in their patient population. However, in a previered from clinically relevant sources to the species level has ous study of acinetobacter infections in Hong Kong, Siau and been emphasized by several investigators [3, 7]. Precise identico-workers [12] found extensive genotypic variation among fication may help the clinician to evaluate the clinical signifiA. baumannii isolates by arbitrarily primed PCR typing, and cance of the organism and allow broadening of our knowledge contrary to other investigations [6, 10, 11], no obvious epiof the epidemiology, clinical importance, and pathology of the demic strain was observed. different Acinetobacter DNA groups. Siau and colleagues used Another finding that contrasts with the results of other rePCR amplification of the 16S–23S rRNA spacer region for searchers [4, 6, 9, 11] relates to the antimicrobial susceptibility this purpose. Unfortunately, currently available commercial of A. baumannii strains. Whereas multidrug resistance is a identification systems do not permit accurate identification of common feature among A. baumannii in almost any recent Acinetobacter to the species level. More accurate identification study, multidrug resistance (arbitrarily defined as resistance to methods using phenotypic properties, such as growth at differfour or more antibiotics; see table 2 in article by Siau et al.), was only observed in three of 18 strains. Relatedness of Acinetobacter isolates recovered from various sites in individual patients was investigated by Siau et al. with Received 12 August 1998. a PCR-based molecular typing method. With this approach, Reprints or correspondence: Dr. Harald Seifert, Institute of Medical Microbiology and Hygiene, University of Cologne, Goldenfelsstrasse 19-21, 50935 the portal of entry for bacteremia was precisely identified in Cologne, Germany (harald.seifert@uni-koeln.de). one-half of the cases. The finding that most cases represented Clinical Infectious Diseases 1999;28:31–2 catheter-related infections is consistent with previous reports q 1999 by the Infectious Diseases Society of America. All rights reserved. 1058–4838/99/2801–0006$03.00 [6, 10]. The role of a catheter as the portal of entry may