Pneumonia due to Pandoraea Apista after evacuation of traumatic intracranial hematomas:a case report and literature review

An efflux pump in genomic island GI-M202a mediates the transfer of polymyxin B resistance in Pandoraea pnomenusa M202

BACKGROUND

Polymyxin B is considered a last-line therapeutic option against multidrug-resistant gram-negative bacteria, especially in COVID-19 coinfections or other serious infections. However, the risk of antimicrobial resistance and its spread to the environment should be brought to the forefront.

METHODS

Pandoraea pnomenusa M202 was isolated under selection with 8 mg/L polymyxin B from hospital sewage and then was sequenced by the PacBio RS II and Illumina HiSeq 4000 platforms. Mating experiments were performed to evaluate the transfer of the major facilitator superfamily (MFS) transporter in genomic islands (GIs) to Escherichia coli 25DN. The recombinant E. coli strain Mrc-3 harboring MFS transporter encoding gene FKQ53_RS21695 was also constructed. The influence of efflux pump inhibitors (EPIs) on MICs was determined. The mechanism of polymyxin B excretion mediated by FKQ53_RS21695 was investigated by Discovery Studio 2.0 based on homology modeling.

RESULTS

The MIC of polymyxin B for the multidrug-resistant bacterial strain P. pnomenusa M202, isolated from hospital sewage, was 96 mg/L. GI-M202a, harboring an MFS transporter-encoding gene and conjugative transfer protein-encoding genes of the type IV secretion system, was identified in P. pnomenusa M202. The mating experiment between M202 and E. coli 25DN reflected the transferability of polymyxin B resistance via GI-M202a. EPI and heterogeneous expression assays also suggested that the MFS transporter gene FKQ53_RS21695 in GI-M202a was responsible for polymyxin B resistance. Molecular docking revealed that the polymyxin B fatty acyl group inserts into the hydrophobic region of the transmembrane core with Pi-alkyl and unfavorable bump interactions, and then polymyxin B rotates around Tyr43 to externally display the peptide group during the efflux process, accompanied by an inward-to-outward conformational change in the MFS transporter. Additionally, verapamil and CCCP exhibited significant inhibition via competition for binding sites.

CONCLUSIONS

These findings demonstrated that GI-M202a along with the MFS transporter FKQ53_RS21695 in P. pnomenusa M202 could mediate the transmission of polymyxin B resistance.

Outbreak of Pandoraea commovens Infections among Non-Cystic Fibrosis Intensive Care Patients, Germany, 2019-2021

Pandoraea spp. are gram-negative, nonfermenting rods mainly known to infect patients with cystic fibrosis (CF). Outbreaks have been reported from several CF centers. We report a Pandoraea spp. outbreak comprising 24 non-CF patients at a large university hospital and a neighboring heart center in Germany during July 2019-December 2021. Common features in the patients were critical illness, invasive ventilation, antimicrobial pretreatment, and preceding surgery. Complicated and relapsing clinical courses were observed in cases with intraabdominal infections but not those with lower respiratory tract infections. Genomic analysis of 15 isolates identified Pandoraea commovens as the genetically most similar species and confirmed the clonality of the outbreak strain, designated P. commovens strain LB-19-202-79. The strain exhibited resistance to most antimicrobial drugs except ampicillin/sulbactam, imipenem, and trimethoprim/sulfamethoxazole. Our findings suggest Pandoraea spp. can spread among non-CF patients and underscore that clinicians and microbiologists should be vigilant in detecting and assessing unusual pathogens.

Clinical and microbiological features of obstructive cholangitis with bloodstream infection caused by Pandoraea apista identified by MALDI-TOF mass spectrometry and ribosomal RNA sequencing in a cancer patient

Background

Pandoraea species are multidrug-resistant glucose-nonfermenting gram-negative bacilli that are usually isolated from patients with cystic fibrosis (CF) and from water and soil. Reports of diseases, including bloodstream infections, caused by Pandoraea spp. in non-CF patients are rare, and the clinical and microbiological characteristics are unclear. The identification of Pandorea spp. is limited by conventional microbiological methods and may be misidentified as other species owing to overlapping biochemical profiles. Here, we report the first case of obstructive cholangitis with bacteremia caused by Pandoraea apista in a patient with advanced colorectal cancer.

A 61-year-old man with advanced colorectal cancer who underwent right nephrectomy for renal cell carcinoma 4 years earlier with well-controlled diabetes mellitus was admitted to our hospital with fever for 2 days. The last chemotherapy (regorafenib) was administered approximately 3 weeks ago, and an endoscopic ultrasound-guided hepaticogastrostomy was performed 2 weeks ago under hospitalization for obstructive jaundice. Two days prior, he presented with fever with chills. He was treated with piperacillin-tazobactam for obstructive cholangitis and showed improvement but subsequently presented with exacerbation. Bacterial isolates from the blood and bile samples were identified as P. apista using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and 16S ribosomal RNA sequencing. Based on the susceptibility results of the isolates, he was successfully treated with oral trimethoprim-sulfamethoxazole 160 mg/800 mg/day for 14 days for P. apista infection.

Conclusions

Pandoraea species are often misidentified. Therefore, multiple approaches should be used to identify them, and decisions regarding antimicrobial treatment should be based on actual in vitro susceptibility. Only seven cases of Pandoraea spp. bloodstream infections have been reported, and we report the first case of cholangitis with bacteremia.

Meropenem-Resistant Pandoraea Pneumonia in a Critically Ill Patient With COVID-19

Among patients infected with respiratory viruses, primary coinfection or secondary bacterial pneumonia is common in the severely ill. Pandoraea are multi-drug resistant gram-negative bacilli that have been newly classified in the past 20 years. We present the first reported case of Pandoraea co-infection with SARS-CoV-2 infection. A critically ill gentleman with COVID-19 in acute respiratory distress syndrome (ARDS) requiring mechanical ventilation developed ventilator-associated bacterial pneumonia (VAP). Initial sputum cultures grew Pandoraea species, with subsequent cultures growing P. aeruginosa, and K. pneumoniae as well. The patient failed to improve despite several antibiotic regimens including meropenem. Send-out reference laboratory testing of the Pandoraea species showed susceptibility to amikacin, ciprofloxacin, levofloxacin, imipenem, and minocycline, but resistance to aztreonam, cefepime, ceftazidime, and meropenem. The patient had deteriorated to multi-organ failure by the time minocycline was initiated, and his family had transitioned him into hospice care. Carbapenems are vital agents in the treatment of VAP. Pandoraea species are often resistant to meropenem but often retain in-vitro sensitivity to imipenem-cilastin. Although mainly isolated from respiratory specimens of patients with cystic fibrosis, cases of infection in non-cystic fibrosis patients have been increasingly recognized. The presentation of this case aims to increase awareness of the high drug resistance of this rising species and reduce delays in treatment, especially in COVID-19 coinfection.

Skull base osteomyelitis by Pandoraea apista: An unusual pathogen at unusual location - A case report

Background:

Pandoraea apista is predominantly recovered from the respiratory tract of patients with cystic fibrosis (CF). Authors report first case of central nervous system infection by P. apista in the form of skull base osteomyelitis.

Case Description:

A 67-year-old male presented with complaints of earache and hearing deficit for few months. The radiology was suggestive of skull base osteomyelitis and polypoidal soft tissue extending from the middle cranial fossa to the infratemporal fossa. The sample from the targeted area revealed P. apista on matrix-assisted laser desorption ionization-time-of-flight mass spectrometry. With adequate antibiotic therapy, there was clinicoradiologic improvement. P. apista is an infection exclusively seen in pulmonary infection in patients with CF. We identified its intracranial involvement in a patient for the 1^st time in the literature. The serendipitous diagnosis needs evaluation on specific PCR and matrix-assisted laser desorption spectrometry. The treatment with antibiotics provides a definite cure.

Conclusion:

We report a rare opportunistic infection with central nervous system involvement which can be cured by accurate diagnosis and appropriate antibiotic treatment.

Hepato and nephroprotective activity of methanol extract of Hygrophila spinosa and its antibacterial potential against multidrug resistant Pandoraea sputorum

This research was aimed to evaluate the phytochemical profile, bactericidal activity of Hygrophila spinosa against multidrug resistant Pandoraea sputorum and assess their antioxidant competence against various radicals and studied their hepatoprotective and nephroprotective activity on HepG2 and HEK 293 cell line. The results showed that the methanol extract has various phytochemical components with reasonable quantity. Fortunately, the multidrug-resistant P. sputorum was sensitive (22.8 ± 0.2 mm of the zone of inhibition) at 15 mg mL^-1 concentration of methanol extract. The higher concentration of phenolic and other phytochemical components, showed significant antioxidant activity against ferric, DPPH, hydroxyl, and ABTS radicals, with IC₅₀ values of 71.09, 64.333, 91.157, and 104.931 g mL^-1, respectively. Surprisingly, the methanol extract possesses hepato and nephroprotective activity against CCl₄ and cisplatin-induced cytotoxicity on HepG2 and HEK 293 cell lines, respectively. It maintains the cell viability as up to 90.48% and 90.35% of HepG2 and EK 293 cell line at the concentration of 20 μg mL^-1. The FTIR analysis states that the methanol extract possesses a significant functional group responsible for these multi-potential activities. These results suggest that, the methanol extract of H. spinosa might contain the most significant bioactive components with outstanding medicinal properties.

Complete Genome Sequences of Clinical Pandoraea fibrosis Isolates

Pandoraea fibrosis is a newly identified Gram-negative bacterial species that was isolated from the respiratory tract of an Australian cystic fibrosis patient. The complete assembled genome sequences of two consecutive isolates (second isolate collected 11 months after antibiotic treatment) from the same individual are presented here.