However, results using these arbitrary breakpoints can poorly be associated with genetic confirmation, called genetic BLNAR (gBLNAR). BLNAR identification by gradient tests using ampicillin minimum inhibitory concentration (MIC) breakpoints 12 is called phenotypic BLNAR. 11 Disk diffusion and gradient tests are routinely used to evaluate the antibiotic sensitivity. This is termed β-lactamase-negative ampicillin resistance (BLNAR). Non-enzyme-mediated resistance occurs through mutations in penicillin-binding protein 3 (PBP3), with ftsI gene mutations identified as a cause of decreased β-lactam-binding affinity. influenzae resistance to β-lactams is either enzyme (β-lactamase) or non-enzyme mediated.
![pbp3 ampicillin pbp3 ampicillin](https://www.researchgate.net/publication/333990626/figure/fig4/AS:773505264128001@1561429434371/Expression-of-an-inactivated-PBP3-during-stationary-phase-inhibits-persister-formation.png)
6 There are reports of antibiotic resistance trends in COPD patients, 6, 9, 10 with geographic variations in the types of bacteria in the lungs and antibiotic resistance patterns. Frequent antibiotic treatment predisposes to the development of antibiotic-resistant pathogens, 7 which can occur by mutation. They may also be administered in the stable state to clear infection from colonizing bacteria. 5, 8Īntibiotics are often used to treat COPD exacerbations. influenzae both in the stable state and during exacerbations may also occur. 5 Simultaneous colonization with multiple strains of H. influenzae strains, 5, 6 with antigenic variation 5, 7 allowing evasion of the host immune response. 2, 4 COPD exacerbations may be caused by either new or persisting H. influenzae ( NTHi) is frequently isolated from COPD patients both in the stable state and during exacerbations.
![pbp3 ampicillin pbp3 ampicillin](https://microbiologyjournal.org/wp-content/uploads/2020/09/fg01-12-324x160.jpg)
2, 4 It can be capsulated or noncapsulated based on the presence or absence of a polysaccharide capsule. Haemophilus influenzae is one of the most commonly isolated bacterial pathogens from COPD patients. Bacterial infection increases the levels of airway inflammation. 2 COPD patients appear to have reduced ability to clear bacteria from the airways, 3 predisposing to bacterial colonization both in the stable state and at exacerbation.
![pbp3 ampicillin pbp3 ampicillin](https://www.dovepress.com/cr_data/article_fulltext/s135000/135338/img/COPD-135338-TS03.png)
1 Many COPD patients suffer with exacerbations, defined as an acute deterioration in symptoms greater than the usual day-to-day variation 1 These events are often caused by bacterial infection. COPD is characterized by airflow limitation and the presence of airway inflammation.