A Narrative Review on the Approach to Antimicrobial Use in Ventilated Patients with Multidrug Resistant Organisms in Respiratory Samples—To Treat or Not to Treat? That Is the Question

Abstract

Multidrug resistant organisms (MDRO) are commonly isolated in respiratory specimens taken from mechanically ventilated patients. The purpose of this narrative review is to discuss the approach to antimicrobial prescription in ventilated patients who have grown a new MDRO isolate in their respiratory specimen. A MEDLINE and PubMed literature search using keywords “multidrug resistant organisms”, “ventilator-associated pneumonia” and “decision making”, “treatment” or “strategy” was used to identify 329 references as background for this review. Lack of universally accepted diagnostic criteria for ventilator-associated pneumonia, or ventilator-associated tracheobronchitis complicates treatment decisions. Consideration of the clinical context including signs of respiratory infection or deterioration in respiratory or other organ function is essential. The higher the quality of respiratory specimens or the presence of bacteremia would suggest the MDRO is a true pathogen, rather than colonization, and warrants antimicrobial therapy. A patient with higher severity of illness has lower safety margins and may require initiation of antimicrobial therapy until an alternative diagnosis is established. A structured approach to the decision to treat with antimicrobial therapy is proposed.

The impact of quantitative and semi-quantitative culture of respiratory tract secretions on clinical decisions in a patient with suspected pneumonia – case study

“…This material provides many important microbiological clues indicating the etiology of LRTI, which determine further treatment (9 ,10). It is believed that samples obtained during bronchoscopy are more representative of the presence of true pathogens in the lungs (11,12) . Using a protected specimen brush in the diagnosis of pneumonia has a great advantage.…”

“…It is important to always be aware of the phenomenon of colonization, especially since the endotracheal tube and airway are colonized quickly after intubation (12) . By definition, colonization is the presence of a microorganism on a body surface that does not cause disease in an organism (16,17) .…”

“…By definition, colonization is the presence of a microorganism on a body surface that does not cause disease in an organism (16,17) . Distinguishing colonization from infection is an important factor in making a correct diagnosis, so the use of a quantitative cut-off for the number of CFU is recommended (12,18) . Qualitative and semi-quantitative cultures are considered to have poorer diagnostic value than quantitative cultures (10,12,16).…”

Pathogen Burden Among ICU Patients in a Tertiary Care Hospital in Hail Saudi Arabia with Particular Reference to β-Lactamases Profile

“…7 Still, there is no gold-standard method for diagnosing pneumonia, and the claim used to define this has the least sensitivity and specificity to establish such a diagnosis. 5,8 Hence the support provided by microbiological data to refine diagnostic accuracy is very important. 9 The present study identified and characterized clinical isolates while considering their antibiotic susceptibility.…”