Microbiological analysis of tracheostomy tube biofilms and antibiotic resistance profiles of potentially pathogenic microorganisms

<b>Introduction:</b> In hospitalized patients, tracheostomy tubes (TTs) are susceptible to colonization by biofilm- producing potentially pathogenic microorganisms (PPMs). Contact with TTs, which are situated in a critical region of the body with enormous microbial exposure, may lead to the emer-gence of resistant respiratory infections.</br></br> <b>Objective:</b> Our study aimed to isolate and identify Gram-positive and Gram-negative PPMs, mark their antibiotic resistance and determine the bacteriological pattern of the biofilm colonizing the TTs. </br></br> <b>Methods:</b> The study was conducted on 45 tracheostomy tubes obtained from 45 hospitalized adult patients with tracheostomy with intubation periods ranging from 1 to 28 days. Tracheal aspirates (TA) obtained from polyvinyl chloride (PVC) TTs were used for the analysis. Bacteria in biofilms were identified by standard microbiological techniques, tested for antibiotic resistance and phenotypic resistance according to the EUCAST guidelines and visualized by SEM.</br></br> <b>Results:</b> Out of 45 TTs, 100% were found to be positive in bacterial cultures with 58 PPM isolates (10 spe-cies) correlating well with the SEM findings. Overall, 72% of isolates were Gram-negative bacilli, followed by Gram-positive cocci (28%). Staphylococcus aureus was the predominant bacterium (identified in 35.5% of patients), followed by Klebsiella pneumoniae (identified in 23.8%). Among the Gram-negative PPMs, 50% of isolates were identified as multidrug-resistant (MDR), 8.6% as extremely drug-resistant (XDR) and 5.2% were pandrug-resistant (PDR).</br></br><b>Conclusions:</b> Our study showed a rapid colonization of the TT surface by biofilm- producing PPMs. Patients with tracheosto- mies, also those with non-infectious conditions, were mainly colonized with highly re-sistant bacteria.

Systemic inflammation and the effects of short-term antibiotic treatment for PPM positive patients with stable COPD

Objective

To evaluate patients with stable COPD for the presence of potentially pathogenic microorganisms (PPM), systemic inflammation and the effects of short-term antibiotic therapy in PPM positive patients.

Methods

From January 2016 to June 2017, we enrolled 96 stable COPD patients. Bacterial cultures from sputum collections were quantitated, along with markers for systemic inflammation including serum C-reactive protein (CRP), interleukin-8 (IL-8) and plasma fibrinogen (FIB) in all patients. All enrolled patients were followed for 12 months. Forty patients were identified as PPM positive and were randomly divided into an antibiotic group and a control group. The antibiotic group was treated with moxifloxacin orally for 6 days. Lung function and markers for systemic inflammation were repeatedly measured at 30 days and 6 months in PPM positive subjects.

Results

Binary logistic regression analysis showed that risk factors for PPM positive are bronchiectasis (OR 4.18, 95% CI 1.20-14.59; P=0.025), COPD assessment test (CAT) ≥20 (OR 17.55, 95% CI 2.82-109.18; P=0.002), spontaneous sputum (OR 15.09, 95% CI 1.36-168.02; P=0.027) and sputum purulence (OR 38.43, 95% CI 5.39-274.21; P=0.000). CRP and IL-8 were higher in PPM positive group than those in PPM negative group (P=0.001, P=0.007, respectively), but there were no differences of FIB between the two groups (P=0.086). Compared to the PPM negative group, the rate of acute exacerbation of COPD was higher (P=0.029) and time to next acute exacerbation was shorter (P=0.030) in PPM positive group. There were no differences in lung function and systemic inflammatory markers either in the control group or the antibiotic group at different time points of follow-up.

Conclusion

PPM exists in stable COPD patients and can cause systemic inflammation and is associated with acute exacerbation of COPD. Short-term antibiotic therapy had no effect on systemic inflammation nor on acute exacerbation of COPD.China Clinical Trials Registry: ChiCTR-IOR-15006769.