Prevalence of multidrug-resistant Gram-negative bacteria from blood cultures and rapid detection of beta-lactamase-encoding genes by multiplex PCR assay

Introduction This study aimed to determine the prevalence of multidrug-resistant Gram-negative bacteria (GNB) from blood cultures in a tertiary-care hospital and the multiplex PCR assay's ability to detect resistance genes. Methods A total of 388 GNB isolates obtained from hospitalized patients between November 2019 and November 2021 were included in the study. Antimicrobial susceptibility testing was done by VITEK 2 system and broth microdilution method. Beta-lactamase-encoding genes were detected by multiplex PCR assays, BioFire-Blood Culture Identification 2 (BCID2) panel (bioMerieux, France). Extended-spectrum beta-lactamases (ESBLs) were detected phenotypically with VITEK AST-GN71 card (bioMerieux, France). The isolates of GNB were classified into multidrug-resistant, extensively-drug-resistant, and pandrug-resistant categories, and their prevalence and distribution in different wards, including coronavirus diseases 2019 (COVID-19) intensive care units (ICU), were calculated. Results Results revealed that all isolates of Acinetobacter baumannii and Pseudomonas aeruginosa were multidrug-resistant as well as 91.6% of Enterobacter cloacae, 80.6% of Proteus mirabilis, and 76.1% of Klebsiella pneumoniae, respectively. In fermentative bacteria, blaOXA-48-like (58.1%), blaNDM (16.1%), blaKPC (9.7%) and blaVIM (6.5%) genes were detected. More than half of Enterobacter cloacae (58.3%) and Klebsiella pneumoniae (53.7%) produced ESBLs. Among non-fermenters, the blaNDM gene was carried by 55% of Pseudomonas aeruginosa and 19.5% of Acinetobacter baumannii. In the COVID-19 ICU, Acinetobacter baumannii was the most common isolate (86.1%). Conclusions This study revealed high proportions of multidrug-resistant blood isolates and various underlying resistance genes in Gram-negative strains. The BCID2 panel seems to be helpful for the detection of the most prevalent resistance genes of fermentative bacteria.Copyright © GERMS 2022.

Tracheobronchopathia Osteochondro-What? A Rare Disorder of the Airway

Airway abnormalities may be due to a multitude of conditions. Symptoms do not occur until there is very significant narrowing, and therefore these conditions are often incidentally found. It is important to consider a broad differential.This case is a 47 year old woman with history of mild intermittent asthma and chronic sinusitis who presented to the emergency department with four weeks of malaise, shortness of breath, cough, and two days of hemoptysis. On CT imaging she was found to have tracheal wall thickening, calcifications and projections along the trachea, as well as extensive right upper and middle lobe, and lingular ground glass opacities as seen in figure 1. With hindsight, similar tracheal abnormalities were noted on chest x-ray in 2019. During admission, ENT was consulted and she was noted to have saddle nose deformity. Nasal biopsy was performed and revealed evidence of chronic inflammation, but no other abnormalities. Extensive workup was performed including rheumatologic workup with mildly positive ANA, mildly elevated ESR and CRP, negative ANCAs, MPO, PR3, RF. Bronchoscopy was pursued and direct visualization of nodules were noted along the anterior and lateral aspects of the trachea, as well as narrowing of the right upper lobe segmental bronchi, also seen in figure 1. Bronchoalveolar lavage cultures revealed Citrobacter freundii complex, Group G beta hemolytic streptococcus, Providencia rettgeri, Enterococcus avium, Pseudomonas aeruginosa, Klebsiella pneumoniae, in addition to rhinovirus and COVID-19. Biopsy was not performed due to patient intolerance of the procedure and desaturation. Ultimately, the pulmonary infiltrates were felt to be a separate process from the tracheal nodules. She improved clinically, and was discharged on antibiotic therapy with a plan for close outpatient follow up.Tracheobronchopathia osteochondroplastica (TO) is a rare condition. Imaging is often the first clue, as symptoms come late in disease course. The differential diagnosis of imaging findings consistent with TO include relapsing polychondritis, granulomatosis with polyangiitis, amyloidosis, along with a host of others. Diagnosis of TO often requires multidisciplinary involvement to evaluate other etiologies,and ultimately bronchoscopy for direct visualization. (Table Presented).

Pan-drug resistant Providencia rettgeri contributing to a fatal case of COVID-19.

Following prolonged hospitalization that included broad-spectrum antibiotic exposure, a strain of Providencia rettgeri was cultured from the blood of a patient undergoing extracorporeal membrane oxygenation treatment for hypoxic respiratory failure due to COVID-19. The strain was resistant to all antimicrobials tested including the novel siderophore cephalosporin, cefiderocol. Whole genome sequencing detected ten antimicrobial resistance genes, including the metallo-ß-lactamase bla NDM-1, the extended-spectrum ß-lactamase bla PER-1, and the rare 16S methyltransferase rmtB2.