Matrix-assisted Laser Desorption Ionisation Time-of-flight Mass Spectrometry Rapid Detection of Carbapenamase Activity in Acinetobacter baumannii Isolates

Clinical significance of rapid detection and diagnosis of Listeria infection in blood with mass spectrometry

OBJECTIVE

Listeriosis is caused by the bacterium, Listeria monocytogenes, and is a significant health concern because of high hospitalization and mortality rates. This study reports seven cases of pregnancy-associated listeriosis diagnosed with matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry performed on infection-positive blood culture.

METHODS

Blood culture-positive samples of seven patients whose pregnancy was complicated by Listeria infection and treated at Xuanwu Hospital of Capital Medical University between January 2016 and December 2021 were analyzed retrospectively. Strains identified by MALDI-TOF mass spectrometry were compared with colony identification results. Identification accuracy and consistency were assessed.

RESULTS

A total of seven strains of Listeria were collected from seven pregnant women presented with fever (37.6-39.9°C). Clinical abnormalities included abnormal liver function, emaciation, hypoalbuminemia, hypocalcemia, hypokalemia, hyponatremia, ketosis, mild to moderate anemia, leukopenia, and thrombocytopenia. Compared with the traditional culture method, MALDI-TOF mass spectrometry led to much earlier identification (4-6 h vs. 3-4 days) with 100% identification accuracy. Of the seven pregnancies complicated by Listeria, only two led to live births. Of the five fetal deaths, three occurred in the second trimester.

CONCLUSION

In this series of pregnancy-associated listeriosis cases, the fetal mortality rate was 71%. MALDI-TOF mass spectrometry is a valuable method that can identify Listeria from blood culture rapidly and accurately.

Multidrug-Resistant Acinetobacter baumannii Infections in the United Kingdom versus Egypt: Trends and Potential Natural Products Solutions

Acinetobacter baumannii is a problematic pathogen of global concern. It causes multiple types of infection, especially among immunocompromised individuals in intensive care units. One of the most serious concerns related to this pathogen is its ability to become resistant to almost all the available antibiotics used in clinical practice. Moreover, it has a great tendency to spread this resistance at a very high rate, crossing borders and affecting healthcare settings across multiple economic levels. In this review, we trace back the reported incidences in the PubMed and the Web of Science databases of A. baumannii infections in both the United Kingdom and Egypt as two representative examples for countries of two different economic levels: high and low-middle income countries. Additionally, we compare the efforts made by researchers from both countries to find solutions to the lack of available treatments by looking into natural products reservoirs. A total of 113 studies reporting infection incidence were included, with most of them being conducted in Egypt, especially the recent ones. On the one hand, this pathogen was detected in the UK many years before it was reported in Egypt; on the other hand, the contribution of Egyptian researchers to identifying a solution using natural products is more notable than that of researchers in the UK. Tracing the prevalence of A. baumannii infections over the years showed that the infections are on the rise, especially in Egypt vs. the UK. Further concerns are linked to the spread of antibiotic resistance among the isolates collected from Egypt reaching very alarming levels. Studies conducted in the UK showed earlier inclusion of high-throughput technologies in the tracking and detection of A. baumannii and its resistance than those conducted in Egypt. Possible explanations for these variations are analyzed and discussed.

Evaluation of salivary parameters and Streptococcus' Mutans count in children with cerebral palsy in Egypt: a case control study

BACKGROUND

Children with cerebral palsy (CP) are at high risk for dental caries. Alteration of some salivary properties encountered among them compared to healthy children, could play a role in this elevated risk.

OBJECTIVES

The aim of the present study was to assess salivary physicochemical properties; including total antioxidant (TAC), flow rate, viscosity, pH and buffering capacity, as well as Streptococcus mutans level among children with CP, also to correlate these variables to their caries experience.

MATERIALS AND METHODS

This case control study included 80 children with CP, study group (SG) and matched number of healthy children for control group (CG). Interview-based questionnaire, clinical examination, salivary biochemical and microbiological investigations using MALDI-TOF were done.

RESULTS

In SG, the caries experience in primary teeth dmft and S. mutans log value were significantly higher than CG (P = 0.039, P = 0.002) while unstimulated salivary flow rate, buffering capacity and salivary TAC were significantly lower (P < 0.0001). Multivariate linear regression showed that the presence of CP was significantly associated with the greatest variation in caries experience in the primary teeth and permanent teeth. Higher unstimulated salivary flow rate, or an increase in buffering capacity by 1 ml of acid/ml of saliva were associated with lower number of the affected primary and permanent teeth. On the other hand, One-unit increase in S. mutans log count and higher salivary TAC were associated with higher caries experience.

CONCLUSION

Children with CP have higher caries experience (dmf) due to lower salivary protective factors and higher S. mutans counts.

Aspergillus derived mycotoxins in food and the environment: Prevalence, detection, and toxicity

Aspergillus species are the paramount ubiquitous fungi that contaminate various food substrates and produce biochemicals known as mycotoxins. Aflatoxins (AFTs), ochratoxin A (OTA), patulin (PAT), citrinin (CIT), aflatrem (AT), secalonic acids (SA), cyclopiazonic acid (CPA), terrein (TR), sterigmatocystin (ST) and gliotoxin (GT), and other toxins produced by species of Aspergillus plays a major role in food and human health. Mycotoxins exhibited wide range of toxicity to the humans and animal models even at nanomolar (nM) concentration. Consumption of detrimental mycotoxins adulterated foodstuffs affects human and animal health even trace amounts. Bioaerosols consisting of spores and hyphal fragments are active elicitors of bronchial irritation and allergy, and challenging to the public health. Aspergillus is the furthermost predominant environmental contaminant unswervingly defile lives with a 40-90 % mortality risk in patients with conceded immunity. Genomics, proteomics, transcriptomics, and metabolomics approaches useful for mycotoxins' detection which are expensive. Antibody based detection of toxins chemotypes may result in cross-reactivity and uncertainty. Aptamers (APT) are single stranded DNA (ssDNA/RNA), are specifically binds to the target molecules can be generated by systematic evolution of ligands through exponential enrichment (SELEX). APT are fast, sensitive, simple, in-expensive, and field-deployable rapid point of care (POC) detection of toxins, and a better alternative to antibodies.

Detection of carbapenemase producers by matrix-assisted laser desorption-ionization time-of-flight mass spectrometry (MALDI-TOF MS)

Matrix-assisted laser desorption-ionization time-of-flight mass spectrometry (MALDI-TOF MS) has been recently applied in detection of carbapenemase-producing Gram-negative isolates. In the present study, we review the latest developments in this field.