From the Authors

Comparative Genomic Analysis and Phenotypic Characterization of Bronchoscope-Associated Klebsiella aerogenes

Bronchoscopes have been linked to outbreaks of nosocomial infections. The phenotypic and genomic profiles of bronchoscope-associated Klebsiella aerogenes isolates are largely unknown. In this work, a total of 358 isolates and 13 isolates were recovered from samples after clinical procedures and samples after decontamination procedures, respectively, over the five months. Antimicrobial susceptibility testing found seven K. aerogenes isolates exhibiting a low-level resistance to antimicrobial agents. Among seven K. aerogenes isolates, we found five sequence types (STs) clustered into three main clades. Collectively, this study described for the first time the phenotypic and genomic characteristics of bronchoscope-associated K. aerogenes.

Does Rigid Bronchoscopy Induce Bacterial Translocation?

BACKGROUND

Although some reports suggest that bronchoscopy induces bacterial translocation (BT), the mechanisms of BT remain unclear.

OBJECTIVE

We aimed to assess whether bronchoscopy or hypoxemia during bronchoscopy is responsible for BT.

METHODS

We evaluated 24 rats divided into three subgroups: the control group (group 1, n = 8); the rigid bronchoscopy group (group 2, n = 8), and the group receiving bronchoscopy + mechanical ventilation (group 3, n = 8). Oxygen saturation (SaO(2)) was measured during the bronchoscopic procedure. Blood and tissue cultures from mesenteric lymph nodes (MLNs), liver, spleen and cecal contents were obtained 24 h following bronchoscopy.

RESULTS

In group 2, SaO(2) was significantly lower than in groups 1 and 3 (p < 0.01). In group 2, BT significantly increased (6/8, 75%; p < 0.01 vs. group 1, and p < 0.05 vs. group 3). The main site of translocation was MLNs (6/8, 75%) in group 2, while BT was detected in only 1 rat in group 3 (1/8, 12.5%).

CONCLUSION

Hypoxemia during rigid bronchoscopy resulted in intestinal mucosal damage in a rat model. Hypoxemia may have been the trigger for BT from the intestine following bronchoscopy.