Clinical characteristics of tertiary hospital patients from whom Acinetobacter calcoaceticus-Acinetobacter baumannii complex strains were isolated.
OBJECTIVE
Acinetobacter baumannii is a worldwide nosocomial pathogen that has become increasingly common over the past few decades, and strains of multidrug-resistant A. baumannii have been increasing. The aim of this study was to assess the clinical characteristics of A. calcoaceticus-A. baumannii complex (Acb complex) strains and to determine the risk factors of this infection.


METHODS
The medical records of 121 patients at Nagasaki University Hospital from whom Acb complex had been isolated between January 2007 and December 2009 were retrospectively reviewed. Patient backgrounds, sensitivity to antibiotics, risk factors for infection, and prognosis were evaluated.


RESULTS
Lower respiratory isolates accounted for 73% (147 strains) of all 201 isolates. Most of the isolates were sensitive to carbapenems. Of the 121 patients (74 males and 47 females; mean age: 62.1 years), 48 (39.7%) had malignancy and 75 (62.0%) were treated with antibiotics prior to isolation. Thirty-seven of the patients in this study (30.6%) were infected by Acb complex and the most frequent clinical manifestation was pneumonia (18 cases; 48.6%). Approximately 60% of infected patients were treated with β-lactam agent in combination with β-lactamase inhibitors or carbapenems. The mortality rate of infected patients was significantly higher than that of colonized patients (infected: 24.3%, colonized: 6.0%, p<0.05). Risk factors for Acb complex infection include being over 60 years of age, chronic liver disease, and the use of first-generation cephalosporins prior to isolation.


CONCLUSIONS
Acb complex was relatively sensitive to antibiotics. The appropriate usage of antibiotics should be continued for the prevention of drug resistance in Acb complex.
Department of Laboratory Medicine, Nagasaki University Graduate School of Biomedical Sciences, Japan.
Koichi
K
Yamada
Katsunori
K
Yanagihara
Nobuko
N
Araki
Yosuke
Y
Harada
Yoshitomo
Y
Morinaga
Norihiko
N
Akamatsu
Junichi
J
Matsuda
Koichi
K
Izumikawa
Hiroshi
H
Kakeya
Yoshihiro
Y
Yamamoto
Hiroo
H
Hasegawa
Shigeru
S
Kohno
Shimeru
S
Kamihira
D000151:Acinetobacter Infections / Q000188:drug therapy / Q000209:etiology* / Q000382:microbiology / Q000401:mortality; D040981:Acinetobacter baumannii / Q000302:isolation & purification; D016954:Acinetobacter calcoaceticus / Q000302:isolation & purification; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003428:Cross Infection / Q000188:drug therapy / Q000209:etiology* / Q000382:microbiology / Q000401:mortality; D005260:Female; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012189:Retrospective Studies; D012307:Risk Factors