Impaired phagocytosis of capsular serotypes K1 or K2 Klebsiella pneumoniae in type 2 diabetes mellitus patients with poor glycemic control.
BACKGROUND
Diabetes mellitus (DM) and capsular serotypes K1 and K2 Klebsiella pneumoniae have been identified as risk factors for liver abscess and complicated endophthalmitis.


OBJECTIVE
The objective of this study was to determine whether poor glycemic control contributes to the development of capsular serotype K1 or K2 K. pneumoniae liver abscess.


METHODS
Neutrophil phagocytosis in patients with type 2 DM and nondiabetic controls was compared with isolates from liver abscess. Phagocytic rates of 18 K1/K2 and nine non-K1/K2 K. pneumoniae strains were evaluated by flow cytometry and electron microscopy. PATIENTS OR STUDY PARTICIPANTS: Forty patients with type 2 diabetes, 14 with good glycemic control, 26 with poor glycemic control, and 13 age-matched healthy normal subjects, were studied.


METHODS
Phagocytic rate of K. pneumoniae was measured.


RESULTS
Phagocytosis of serotype K1/K2 isolates by neutrophils from diabetics was significantly less than normal controls (P < 0.01). Further analysis revealed that, in type 2 DM patients with poor glycemic control, phagocytosis of K1/K2 was remarkably impaired at 10 min (25.2 +/- 1.7 vs. 42.4 +/- 1.8%) and persisted until 60 min (51 +/- 1.2 vs. 59.4 +/- 1.4%; P < 0.01), but in type 2 DM patients with good glycemic control were similar at 10 min (38.2 +/- 1.7% vs. 42.4 +/- 1.8%) and at 60 min (57 +/- 0.3% vs. 59.4 +/- 1.4%; P = 0.2). No significant difference in the phagocytosis of non-K1/K2 K. pneumoniae among all subjects was observed.


CONCLUSIONS
Poor glycemic control plays a role in impairing neutrophil phagocytosis of K1/K2 K. pneumoniae, but does not significantly affect the phagocytosis of non-K1/K2 K. pneumoniae. This study identifies poor glycemic control as a risk factor for susceptibility to serotype K1/K2 K. pneumoniae liver abscess and complicated endophthalmitis.
Lin
Jung-Chung
JC
Department of Internal Medicine, Tri-Service General Hospital, #325 Section 2 Cheng-Kung Road, Neihu, Taipei 114, Taiwan, Republic of China.
Siu
L K
LK
Fung
Chang-Phone
CP
Tsou
Hsiao-Hui
HH
Wang
Jaang-Jiun
JJ
Chen
Chiung-Tong
CT
Wang
Shu-Chuan
SC
Chang
Feng-Yee
FY
D000328:Adult; D000368:Aged; D016667:Bacterial Capsules / Q000276:immunology*; D001786:Blood Glucose / Q000032:analysis*; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000276:immunology*; D005260:Female; D006801:Humans; D007711:Klebsiella pneumoniae / Q000145:classification* / Q000276:immunology*; D008297:Male; D046529:Microscopy, Electron, Transmission; D008875:Middle Aged; D009504:Neutrophils / Q000276:immunology / Q000648:ultrastructure; D010587:Phagocytosis / Q000276:immunology*; D012703:Serotyping; D013997:Time Factors
D001786:Blood Glucose