Feature Papers in Medical Microbiology in 2024

Traditional methods of detecting foodborne pathogens take several days to produce the required results. Furthermore, various molecular techniques (e.g., PCR) that also produce reliable results in the detection of pathogenic bacteria have been introduced, but the cost–time ratio required does not allow them to be considered a substantial solution to this specific problem. Three-dimensional (3D) printing technology provides the ability to design and manufacture microfluidic analytical devices using conventional 3D printers, which, in combination with colorimetric loop-mediated isothermal amplification (LAMP), may further simplify the process. The overall reduction in time and cost may provide the opportunity to upscale this diagnostic modality. Moreover, unlike most microfluidic analytical devices, this technique is simpler and more user-friendly, as it does not require any expertise or additional equipment apart from a conventional oven. A 3D-printed microfluidic analytical device in combination with LAMP was developed and tested for the simultaneous detection of foodborne pathogens in food samples. A total of 150 commercial food specimens (50 milk, 50 chicken, 50 lettuce samples) were analyzed for possible contamination with Salmonella typhimurium, Listeria monocytogenes and Escherichia coli. The 3D-printed microfluidic device was 100% precise for both negative (80 samples) and positive samples (7 samples were positive for S. typhimurium, 28 for L. monocytogenes, and 35 for E. coli) for all pathogens. Overall, the amount of data analyzed led to a high level of confidence in the precision of this device. As such, this new 3D device in combination with LAMP provides a precise detection method for food pathogens with a low detection limit. Full article

Retroviral and hepatitis B infections can be potential threats to foetomaternal health through inducing distortions of the architecture and structure of the placenta. Improved insights into the effects of these infections on placental morphology would be integral to our understanding of maternal and neonatal health. Aim: To histomorphologically and stereologically investigate selected placental structures in virus-infected (HIV [human immunodeficiency virus] and hepatitis B virus [HBV]) and uninfected women at term. Method: This cross-sectional study involved the screening of 237 placentae collected at term (38 ± 2 weeks) from the maternity delivery units and surgical theatres of the LEKMA and Weija/Gbawe Municipal Hospitals in Accra. Venous blood samples from the umbilical vein and placenta basal plate blood were screened for HIV, HBV, and hepatitis C virus (HCV) using serological test kits (RDT). A total of 34 placentae were selected, comprising 20 cases and 14 controls that were gestational age-matched. Using stereology and a systematic random sampling technique with test point and intersection counting of photomicrographs, the mean volume densities of syncytial knots, syncytial denudations, foetal capillaries, and intervillous spaces of the placentae were estimated on a total of 2720 photomicrographs. Results: On stereological assessment, there was a statistically significant difference in the mean volume densities of syncytial knots (HIV-infected = 0.562 ± 0.115, HBV-infected = 0.516 ± 0.090, control group = 0.171 ± 0.018, p = 0.001), syncytial denudations (HIV-infected = 0.121 ± 0.022, HBV-infected = 0.111 ± 0.016, control group = 0.051 ± 0.00, p = 0.004), and foetal capillaries (HIV-infected = 0.725 ± 0.152, HBV-infected = 0.902 ± 0.078, control group = 0.451 ± 0.064, p = 0.006) among the different groups of placentae (control) at term. A statistically significant decrease in intervillous space (p = 0.022) was recorded in HBV-infected placentae compared to the control (from 15.450 ± 1.075 to 11.32 ± 0.952). Conclusion: Placental viral infections might lead to significant increases in syncytial knots, foetal capillaries, and syncytial denuded areas of the chorionic villi and a significant decrease in intervillous spaces. This finding could signify evidence of advanced gestation, placental malperfusion, hypermaturity of the placenta, and a possible vertical transmission of the viral antigen to the foetus, which may be crucial in understanding perinatal outcomes. Full article

Biofilms exert a profound impact on various facets of human life. Positive instances of biofilm usage involve their capacity to immobilize pollutants such as heavy metals, while adverse cases result in infections like urinary tract infections. Therefore, the study of biofilm engineering emerges as crucial. Employing a bibliographic research approach, this paper delves into biofilm engineering, identifying key species like Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus, among others. The investigation also unveils major research subjects and corresponding institutions dedicated to biofilm research. A comprehensive understanding of biofilm engineering holds profound implications for advancing knowledge in this domain. Full article

The COVID-19 pandemic has led to an unprecedented surge in respiratory illness cases worldwide. Although uncommon, pulmonary cavitation has been reported as a potential complication of COVID-19. This case series report describes four cases of COVID-19 patients with lung cavities, highlighting the various causes and clinical manifestations of this complication, and a review of the literature on the presence of lung cavities in COVID-19 patients. In two cases, the cavities were most likely due to secondary bacterial superinfections, with one case being complicated by multi-drug-resistant bacteria. Another case developed cavities secondary to a fungal infection, while the third case was directly caused by SARS-CoV-2 invasion in the lungs. The presence of cavities with or without air-fluid level or pneumothorax in COVID-19 patients should be considered as a potential complication of this infection, especially in those with respiratory symptoms. Physicians should remain vigilant for the development of pulmonary cavitation in COVID-19 patients, particularly those receiving high doses of steroids. Additionally, spontaneous pneumothorax should be considered an alarming sign in COVID-19 patients. Full article

Urinary tract infections (UTIs) cause a significant infectious burden in the community and demand a coordinated approach from all first-line health professionals. Uncomplicated UTIs refer to infections in non-pregnant females without any underlying localized or generalized pathology, diagnosed through history by the presence of specific local symptoms and in the absence of systemic ones like fever. Uncomplicated UTIs are usually caused by Escherichia coli species; thus, empirical antibiotic treatment can be immediately initiated. A percentage of patients can experience a resolution of symptoms without therapy; however, this “wait and observe” approach is supported only by the relevant British guidelines. There are limited quality studies in the literature on adjuvant treatment options; these can include BNO 145, a phytotherapeutic medicine, and XHP, a medical technology product. Despite being licensed by the European Medicines Agency on the basis of traditional use, there is inadequate support in the medical literature for the use of cranberry extracts and Arctostaphylos uva-ursi extracts. The use of antibiotics is associated with higher response rates and urine culture sterilization as well as lower recurrence/relapse rates; on the other hand, side effect rates are also higher. In choosing the proper empirical antibiotic therapy, one has to take into account individual patient characteristics and community resistance patterns as well as the antimicrobial resistance pressure exerted by the wide use of a specific antibiotic. There is a need for a common framework through which all frontline health practitioners should operate when faced with a case of uncomplicated UTI. In Greece, there are three different guidelines for UTI treatment, developed by the Ministry of Health, the National Organization for Medicines, and the Hellenic Society for Infectious Diseases. The authors of the present study aim at synthesizing these guidelines as well as relevant guidelines from international scientific or other national regulatory organizations while taking into account local resistance patterns. The authors propose the first-line use of either fosfomycin, nitrofurantoin, or pivmecillinam. The use of trimethoprim/sulfamethoxazole is discouraged due to increased resistance of Greek community E. coli isolates. Fluoroquinolone use should be avoided due to high E. coli community resistance (exceeding 20% for Greece), along with their unfavorable benefit/side effect balance in uncomplicated UTIs, as well as the overall community resistance pressure exerted by their use. A 5-day regimen remains superior to a 3-day one; the latter may be suitable for certain, not yet adequately characterized, patients. Full article

The endometrial cavity was considered sterile until the second half of the 20th century. Through modern technological advances and the sequencing of the bacterial 16S rRNA gene, it was proven that the area possesses its own unique microbiome, which can be categorised into two types, Lactobacillus-dominant (LD, with a Lactobacillus spp. abundance percentage greater than 90%) and non-Lactobacillus-dominant (non-LD, with a Lactobacillus spp. abundance percentage smaller than 90%), with other species like Bifidobacterium, Gardnerella, Prevotella, and Streptococcus also being prominent. The aim of this study was to investigate the possible correlation of the endometrial microbiome to female infertility, through the identification and appraisal of studies published in the databases PubMed, Web of Science, and Scopus. Moreover, 12 studies met the research criteria, including the analysis of endometrial fluid or tissue samples from infertile women through PCR, culturomics-based, or NGS methods. According to most of these studies, a eubiotic LD-type microbiome seems to be best for maximising endometrial receptivity and pregnancy chances, whereas a dysbiotic non-LD-type microbiome, with increased α-diversity and a higher number of pathogens, has a harmful effect. There were few studies that presented contradictory results without, however, a satisfactory explanation. Thus, more time and a greater number of studies are required to clarify contradictions and achieve more certain results. Full article