ACTA Microbiologica Hellenica (Volume 67, Issue 4)

COVID-19 infection and cold antibody autoimmune hemolytic anemia

Maria Kehagia, Rea Chatzikyriakou
Hematology Laboratory of General Hospital of Athens “Sismanoglio-Amalia Flemig” – “Sismanoglio” Hospital Unit

Several case reports have implicated an association between COVID-19 infection and autoimmune hemolytic anemia, a known hematologic sequel of various infections. Given the complexity of the pathophysiologic relationship between SARS-CoV-2 infection and autoimmune hemolysis, the underlying mechanisms proposed so far have not yet been fully elucidated. Despite the still sparse case reports and possible underreporting, cold antibody hemolytic anemia in the setting of COVID-19 is of particular interest, with the number of its cases growing since the start of the pandemic.

Keywords: COVID-19, infections, autoimmune hemolytic anemia, cold antibodies

Pathophysiology of severe COVID-19 infection: predisposing factors and evolution

Ioannis Chonianakis1, Eleutheria Giachanou1, Maria Anna Kyriazidi2, Sotiris Varlamis1, Asimoula Kavvada2, Christos Tenis1, Maria Chatzidimitriou1
1 International Hellenic University, 2 Aristotle University of Thessaloniki

An extremely contagious virus SARS-CoV-2 emerged two years ago causing COVID-19 infection and resulting to the current pandemic, the most challenging public health crisis we have ever faced. The virus is transmitted through the respiratory tract, mostly by inhalation of aerosols, and although its virulence was initially focused mainly on the lower respiratory system, now through evolutionary mechanisms and mutations of the viral genome, it has been confined to the upper respiratory system. The COVID-19 disease presents a very wide spectrum of severity, ranging from subclinical infection (asymptomatic), mild symptoms, to critical cases, not rarely fatal. The severity of the disease depends on the immune response of the host. Ιn critical cases, hyperinflammation and hyperreaction processes of the innate and adaptive immune systems are observed, ultimately resulting in Cytokine Storm Syndrome and cases of hypercoagulation. Severely ill patients may develop acute lymphopenia, eosinopenia and neutrophilia, and/or rapidly increased levels of D-dimers. Characteristic complications of the disease are pneumonia and Acute Respiratory Distress Syndrome (ARDS), which represent severe and life-threatening conditions. This review will explain the precise mechanisms concerning the pathophysiology of the severe COVID-19 infection. Firstly, we will analyze the excessive immune response and the extensive inflammation that follows during the emergent condition known as Cytokine Storm Syndrome. Furthermore, we will research complications related to hypercoagulation and thrombus formation, with particular reference to the development of pulmonary embolism and the aggressive activation of the complement system. In addition, references will be made to predisposing factors, such as genetic mutations and blood groups, which have been associated with the aggravated symptomatology of the infection, as well as to mechanisms of inhibition of the immune response disposed to SARS-CoV-2, data that need further clarification. Finally, the evolutionary course of the virus from the beginning of the pandemic until today will be explained by grouping the strains of variants of concern (VOC) and mentioning the differences between them, both at the genetic level and the properties that each emerging mutation provides.

Key words: COVID-19, SARS-CoV-2, ARDS, Cytokine Storm, hypercoagulation, mutations

Vaborbactam: perspective of a new β-lactamase inhibitor in the antimicrobial chemotherapy

Eirini Amargianitaki, Vasiliki Koumaki, Athanassios Tsakris, Joseph Papaparaskevas
Department of Microbiology, Medical School, National and Kapodistrian University of Athens

Infections due to carbapenem-resistant Enterobacterales, Pseudomonas aeruginosa, and Acinetobacter baumannii constitute a global public health threat and are associated with high morbidity and mortality rates. Resistance is mainly due to the production of various types of carbapenemases. Vaborbactam is a novel boronic acid-based β-lactamase inhibitor with high potency against class A carbapenemases, including KPC variants. Combined with meropenem, it almost fully restores its activity against KPC carbapenemase-producing Enterobacterales. However, it has limited activity against carbapenem-resistant Pseudomonas aeruginosa and Acinetobacter baumannii. Clinical efficacy and safety of the combination were evaluated in two clinical trials, TANGO I and II: it was proved to be non-inferior compared to other therapeutic options. It was also found safe, having few serious adverse effects, especially in terms of nephrotoxicity. Based on available in vitro and in vivo data it appears to retain a low propensity for resistance selection. Vaborbactam exhibits pharmacokinetic properties similar to those of meropenem. Meropenem-vaborbactam has been approved for use in adults with complicated urinary tract and intrabdominal infections, hospital-acquired and ventilator-associated pneumonia, as well as infections due to aerobic Gram-negative organisms in adults with limited treatment options. Studies regarding its use in real-life settings show promising clinical cure rates and lower rates of adverse effects, even when it comes to cases of very fragile patients.

Keywords: carbapenem resistant organisms, Klebsiella pneumoniae carbapenemase, vaborbactam, meropenem-vaborbactam

A comprehensive review of monkeypox (mpox) on the occasion of the ongoing multicountry outbreak of the disease

Panagiotis Toumasis1, Vasileios Paparizos2, Georgia Vrioni1
1 Department of Microbiology, Medical School, National and Kapodistrian University of Athens, Athens, Greece.
2 Sexually Transmitted Infections Unit, 1st Department of Dermatology and Venereology, Andreas Syggros
University Hospital of Athens, Athens, Greece.

The ongoing recent outbreak of mpox, extending to both endemic and non endemic regions, has emerged as a growing international public health threat. The purpose of this review is to highlight the basics of the disease. Mpox is a zoonotic infectious disease, caused by MPV, a DNA virus in the genus Orthopoxvirus. There are two possible means of mpox transmission: animal-to-human and human-to-human transmission. In this epidemic, mpox is predominantly affecting men who have sex with men. The early symptoms and signs of mpox are nonspecific but the subsequent evolution of the skin lesions is characteristic. The preferred diagnostic method for mpox is Polymerase Chain Reaction (PCR) testing of samples from skin lesions. The management of mpox includes supportive care and pain relief medication. There is no treatment approved specifically for mpox. However, there is evidence that antiviral agents that are effective against variola virus are also effective against MPV. There are several simple precautions in order to avoid mpox, including vaccination.

Keywords: mpox, outbreak, epidemic

Multi-locus sequence typing (MLST) of clinical isolates of methicillin-resistant Staphylococcus aureus (MRSA) from systemic infections in two hospitals in Quito-Ecuador

Doménica Andrade1, Tatiana Lara2, Marcelo Grijalva1-2
1 Grupo de Investigación en Sanidad Humana y Animal – GISAH, Departamento de Ciencias de la Vida y la Agricultura, Universidad de las Fuerzas Armadas ESPE, Sangolquí,Ecuador.
2 Centro de Nanociencia y Nanotecnología, Universidad de las Fuerzas Armadas ESPE, Sangolquí, Ecuador.

Methicillin-resistant Staphylococcus aureus (MRSA) infections are currently a serious clinical and epidemiological problem. This opportunistic pathogen has been commonly associated with hospital infections. However, community variants of high infectivity have recently appeared and have raised concerns due to their virulence. In this research, twenty-six clinical isolates from blood cultures belonging to patients from two reference hospitals in Ecuador, were analyzed using Multilocus Sequence Typing (MLST). PCR assays were standardized and optimized for the housekeeping MLST genes (arcC, aroE, glpF, gmk, pta, tpiA, and yqiL) and for the cyclic sequencing reaction required in the Sanger sequencing method, along with necessary purification procedures. The isolates’ allelic variants and their sequence types (ST) were analyzed using the PubMLST database. Eight previously undetermined sequence types (UST) were obtained, along with two alleles with point mutations. The analysis of these data using Maximum Parsimony Trees and Minimum SpanningTrees (MSTree) showed no closer phylogenetic associations for the isolates studied and the most commonly reported clones, demonstrating the emergence of new variants in Ecuador, presumably community-type ones. The present study may contribute to timely clinical and epidemiological surveillance of MRSA infections at a local level.

Keywords: Staphylococcus aureus, Antibiotic resistance, Multilocus sequence typing