Case Series Study of Melioidosis, Colombia

Imaging manifestations of pulmonary melioidosis: A case series

Melioidosis is an endemic disease in Southeast Asia and Oceania caused by the gram-negative bacillus Burkholderia pseudomallei. We studied 15 adult patients from Colombia with microbiologically diagnosed pulmonary melioidosis. We reviewed 15 chest X-rays and 10 chest computed tomography (CT) studies. Of the 15 patients, 87% met the criteria for acute infection and 13% met the criteria for chronic infection. The most common findings on chest X-rays were consolidation (86%), nodules (26%), and cavitation (20%). On CT studies, consolidation and nodules were observed in 90% of cases; the areas of consolidation were predominantly located in the basal and central zones in 60%. Areas of cavitation were observed in 50%, pleural effusion in 60%, and mediastinal lymph nodes in 30%. In patients with acute pulmonary melioidosis (n=8), the findings observed were nodules (100%), mixed pattern with nodules and consolidation (87%), pleural effusion (88%), and mediastinal lymph nodes (25%). The two patients with chronic pulmonary melioidosis both had cavitation. Acute lung infection with B. Pseudomallei has radiologic manifestations similar to those of pneumonia due to other causes. In areas where the disease is endemic, it is essential to include acute melioidosis in the differential diagnosis of pulmonary nodules and chronic melioidosis in the differential diagnosis of cavitated chronic lung lesions.

The Menace of Candida auris Epidemic Amidst the COVID-19 Pandemic: A Systematic Review

Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2), the causative agent for the Coronavirus Disease 2019 (COVID-19) pandemic, has sparked a medical emergency worldwide. With the rise in COVID-19 infections and an eventual increase in hospitalized critically ill patients, a trend of bacterial, fungal, and viral superinfection has been noted. One important agent of co-infection identified is Candida auris. Due to its multidrug-resistant nature and easy transmissibility, C. auris is difficult to manage in COVID-positive patients. Patients with comorbidities, immunosuppressive states, intubated and on ventilators are more likely to contract the fungal infection. Therefore, it is essential to the first screen, diagnose, and isolate patients with C. auris infection and manage and treat them while preventing the spread of the disease. Failure to recognize and prevent its spread may lead to an eventual epidemic or even a pandemic during the current COVID-pandemic, which the exhausted healthcare system can most definitely not handle. This systematic review investigates the prevalence of C. auris, its pathophysiology, diagnosis, prevention, and treatment during the COVID-19 pandemic.

Antimicrobial Susceptibility of Western Hemisphere Isolates of Burkholderia pseudomallei: Phenotypic and Genomic Analyses

Current antimicrobial treatment recommendations for melioidosis, the disease caused by Burkholderia pseudomallei, are largely based on studies of strains isolated from the Eastern Hemisphere (EH), where most human cases are identified and reported. In this study, we evaluated the antimicrobial susceptibility of 26 strains in the CDC (Centers for Diseases Control and Prevention) collection from the Western Hemisphere (WH) isolated from 1960 to 2015. Minimal inhibitory concentration (MIC) values were measured by standard broth microdilution for 16 antimicrobials following Clinical and Laboratory Standards Institute (CLSI) guidelines. Twenty-four of the 26 WH strains were susceptible to the six antimicrobials with CLSI-defined MIC susceptibility interpretive criteria for B. pseudomallei: amoxicillin/clavulanate, ceftazidime, imipenem, doxycycline, tetracycline, and trimethoprim/sulfamethoxazole. One WH strain demonstrated intermediate amoxicillin/clavulanate resistance and another strain had intermediate resistance to tetracycline. For all antimicrobials tested, the susceptibility profiles of WH isolates were comparable with previously reported MIC results of EH strains. The overall similarities suggest that the same antimicrobials are useful for melioidosis treatment in both the WH and EH. Using in silico analyses of WH genomes, we identified a novel amino acid substitution P258S in the beta-lactamase PenA, which may contribute to decreased susceptibility to amoxicillin/clavulanate in B. pseudomallei.

Genomic Diversity of Burkholderia pseudomallei Isolates, Colombia

We report an analysis of the genomic diversity of isolates of Burkholderia pseudomallei, the cause of melioidosis, recovered in Colombia from routine surveillance during 2016–2017. B. pseudomallei appears genetically diverse, suggesting it is well established and has spread across the region.

Case Report: Gestational Melioidosis through Perinatal Transmission

Burkholderia pseudomallei is an emerging pathogen in the Americas. Cases of mother-to-child transmission of B. pseudomallei are rare and probably occur by placental or perinatal infection. We report the first case of native gestational and neonatal melioidosis in the Western hemisphere. The isolated strains in the mother and newborn were confirmed by whole-genome sequencing and identified as a novel sequence type ST1748. The comparison of both genomes revealed a nucleotide similarity of 100%. Melioidosis should be considered within the differential diagnosis of febrile illness or pneumonia in pregnant women and newborns from endemic areas of the Americas.

Melioidosis DS rapid test: A standardized serological dipstick assay with increased sensitivity and reliability due to multiplex detection

Background

Melioidosis, caused by Burkholderia pseudomallei, is a severe infectious disease with high mortality rates, but is under-recognized worldwide. In endemic areas, there is a great need for simple, low-cost and rapid diagnostic tools. In a previous study we showed, that a protein multiplex array with 20 B. pseudomallei-specific antigens detects antibodies in melioidosis patients with high sensitivity and specificity. In a subsequent study the high potential of anti-B. pseudomallei antibody detection was confirmed using a rapid Hcp1 single protein-based assay. Our protein array also showed that the antibody profile varies between patients, possibly due to a combination of host factors but also antigen variations in the infecting B. pseudomallei strains. The aim of this study was to develop a rapid test, combining Hcp1 and the best performing antigens BPSL2096, BPSL2697 and BPSS0477 from our previous study, to take advantage of simultaneous antibody detection.

Methods and principal findings

The 4-plex dipstick was validated with sera from 75 patients on admission plus control groups, achieving 92% sensitivity and 97–100% specificity. We then re-evaluated melioidosis sera with the 4-plex assay that were previously misclassified by the monoplex Hcp1 rapid test. 12 out of 55 (21.8%) false-negative samples were positive in our new dipstick assay. Among those, 4 sera (7.3%) were Hcp1 positive, whereas 8 (14.5%) sera remained Hcp1 negative but gave a positive reaction with our additional antigens.

Conclusions

Our dipstick rapid test represents an inexpensive, standardized and simple diagnostic tool with an improved serodiagnostic performance due to multiplex detection. Each additional band on the test strip makes a false-positive result more unlikely, contributing to its reliability. Future prospective studies will seek to validate the gain in sensitivity and specificity of our multiplex rapid test approach in different melioidosis patient cohorts.

The Gram-negative environmental pathogen Burkholderia pseudomallei, causes the severe disease melioidosis. It is highly endemic in southeast Asia and northern Australia, but recent studies suggest that it is also present in many other parts of the world where it is severely underreported. The latter results from the extremely variable and non-specific clinical manifestations of the disease, lack of clinical recognition, and the global scarcity of good quality laboratories to allow diagnosis from microbiological culture. This is even more unfortunate, as early diagnosis of the disease is indispensable for an effective therapy, since B. pseudomallei is intrinsically resistant to many antibiotics used for empirical treatment in endemic areas. Therefore, the development of new, standardized and sensitive tools is of high importance for both diagnostics and epidemiology. We focused on the development of a dipstick assay, which is based on the detection of serum antibodies against four B. pseudomallei specific protein antigens. Here we present a cost effective, simple and rapid melioidosis assay with improved sensitivity that does not depend on sophisticated laboratory equipment and therefore addresses most of the before mentioned obstacles and is easy to manufacture in large scales.