New Delhi Metallo-Β-Lactamase-Producing Carbapenem-Resistant Enterobacteriacae Isolated From Bronchial Washings.

Dear Editor,
The prevalence of Carbapenem resistance among Enterobacteriacae species is increasing and poses a potential major public health risk. In recent years, several new carbapenemases have been identified, including New Delhi metallo-β-lactamase (NDM). A 78-year-old non-smoking female with prior medical history of type 2 diabetes mellitus, gastroesophageal reflux disease (GERD) and prior coronary artery bypass grafting was referred to our respiratory outpatient service for evaluation of a chronic cough and dyspnoea in 2013. Clinical examination revealed bibasal pulmonary crepitations but was otherwise unremarkable. Computed tomography of the chest demonstrated atelectasis of the lingula and right middle lobe. She underwent bronchoscopy, which demonstrated laryngeal mucosa inflammation, consistent with her GERD. There was no growth on bacterial, fungal or mycobacterial bronchial washings cultures.

She represented to our service two years later with self-limiting small volume hemoptysis, attributed to acute bronchitis. This was treated in the community with Moxifloxacin (documented as allergic to penicillin). Microbiologial cultures from a repeat bronchoscopy isolated an Escherichia Coli spp, which was resistant to co-amoxiclav but sensitive to Ciprofloxacin. The following year a further bronchoscopy was performed to investigate recurrent hemoptysis with associated new right basal consolidation on chest radiograph. On this occasion, a carbapenem resistant Klebsiella pneumoniae spp was isolated from bronchial washings cultures. Further analysis identified an NDM-producing carbapenem resistant Enterobacteriaciae (CRE), sensitive only to Gentamicin, Amikacin, Fosfomycin (MIC 16 ul/ml), Colistin (MIC =1.0) and Tigecycline (MIC 0.75 ug/ml). At subsequent clinic review the patient was clinically well. No obvious risk factors for this multidrug resistant coloniser were identified. A stool sample also demonstrated gastrointestinal carriage of the NDM-producing CRE. No evidence of CRE contamination was found in microbiological testing our bronchoscopy equipment and there has been no subsequent case associated with the unit.

Carbapenems were developed in the late 1970s as a derivative of thienamycin, in order to combat the emergence of β-lactamase producing bacteria. The emergence of carbapenem resistance among Enterobacteriaciae spp was recognized in the mid-1990s1. Known carbapenemase enzymes include the NDM, which was first described in 2009 in a Swedish patient hospitalized in India with a Klebsiella Pneumoniae urinary infection2. To date, this carbapenemase has been identified in multiple species of Enterbacteriaceae and has a global geographical distribution3. The first Irish outbreak of NDM CRE occurred in 2014 and was reported in 2016. Clinical samples affected included rectal swab, mid-stream urine and skin biopsy. There were no respiratory cases involved4. Given the limited treatment options and high mortality rates for clinically significant CRE infections, accurate and timely CRE identification and infection prevention and control measures are key to management. To the best of our knowledge ours is the first documented case of NDM CRE isolated from culture of bronchial washings in Ireland and serves to highlight the threat posed by multidrug resistant Enterobacteriacae spp.

Cullivan S1, Brady DM2, O’Callaghan DS1.

Departments of 1Respiratory Medicine and 2Clinical Microbiology, Mater Misericordiae University Hospital.

Sarah Cullivan, Department of Respiratory Medicine, Mater Misericordiae University Hospital.
Email: [email protected]


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