- Volume 74, Issue 1, 2025

Ulcerative colitis (UC) is a chronic inflammatory bowel disease (IBD) that presents significant challenges in terms of treatment owing to a pronounced likelihood of recurrence and an elevated risk of cancer development, thereby imposing substantial risks on affected individuals. The gut microbiota of Firmicutes and Bacteroidetes (F/B) can affect diseases associated with IBD, which is also a risk factor for breast cancer. This review discusses the hazards associated with UC, highlights the existing disparities in UC-associated gut microbiome research, explores the concept of the F/B ratio and scrutinizes its correlation with UC. Moreover, the differences in the F/B ratios between healthy individuals and those with UC were thoroughly examined. These findings suggest that an elevated F/B ratio may promote the occurrence and progression of UC. Consequently, the F/B ratio may play a significant role in UC by influencing gut microbiota composition and inflammatory responses, suggesting that future research should focus on this ratio as a potential biomarker for disease progression and therapeutic targets in managing UC.

Introduction. The rise in antimicrobial resistance poses a significant threat to global health, particularly among diabetic patients who are prone to urinary tract infections (UTIs).

Hypothesis. Pathogens that cause UTI among diabetic patients exhibit significant multidrug resistance (MDR) patterns, necessitating more precise empirical treatment strategies.

Aim. This study aimed to determine the prevalence of UTI among diabetic patients and study the antimicrobial susceptibility profiles of uropathogens, detected and identified the potential differences in age groups and between genders, focusing on MDR and gender-based variations, causing a global concern in deciding empirical treatment.

Methodology. A prospective study was conducted from August 2021 to December 2023 in Gujarat, India. During the period, 1023 diabetic patients with symptoms of UTI were diagnosed by urine culture and 280 individuals tested positive for UTIs. Antibiotic susceptibility testing was carried out on these 280 micro-organism isolates.

Results. Among the 280 UTI-positive patients, 166 (59.29%) were females and 114 (40.71%) were males, with the prevalence of UTI in diabetic females being 27.34% (166/607) and males being 27.40% (114/416). Among the isolated uropathogens, Escherichia coli (56.78%) was the predominant organism followed by Pseudomonas aeruginosa (13.57%) and Klebsiella (13.21%). High resistance was noted to various antibiotics in Gram-negative bacteria including both genders. In E. coli, resistance was predominantly high against the penicillin sub-class of the beta-lactam group (70.23%, 69.58%), cephalosporins (66.23%, 76.52%) and least against nitrofurans (30.10%, 40%) in males and females, respectively. Klebsiella has shown higher resistance to cephalosporins (66.23%, 76.52%) and aminoglycosides (60.92%, 62.66%) and least resistance to carbapenem (41.67%) and phosphonic (33.33%) in males and females, respectively. A high proportion of isolates, ~82.5%, exhibited MDR. Among these MDR isolates, those from female patients accounted for a higher percentage (58.44%) compared with males (41.55%). The highest prevalence of MDR was observed in the 41–60-year age group. This pattern highlights notable differences in MDR prevalence across gender and age groups.

Conclusion. The high prevalence of UTI caused by MDR organisms based on gender and age group highlights the need for clinicians to choose antibiotics more judiciously for empirical treatment, thereby reducing misuse and overuse in the community. For diabetic UTI patients in this region, nitrofurantoin may be recommended for uncomplicated cases due to low resistance in E. coli, while fosfomycin could be a viable alternative for Klebsiella-related infections. Carbapenems may be reserved for severe cases with MDR pathogens, and combination therapy could be considered for complicated infections, particularly in high-risk age groups.

Introduction. Ocular fungal infections are pathologies of slow progression, occurring mainly in the cornea, but can also affect the entire structure of the eyeball. The main aetiological agents are species of the genera Candida and Fusarium. Both diagnosis and treatment require speed and effectiveness. However, the currently available therapy basically consists of the use of azoles and polyenes, known for their low penetration into the ocular tissue and the associated toxicity.

Hypothesis. Thus, new strategies to combat these infections are needed, such as the development of new antifungals or the use of associations.

Aim. Thus, the compound PH151, derived from a promising class of 8-hydroxyquinolines, and natamycin, amphotericin B (AMB) and voriconazole (VRC), the main antifungals used in ocular antifungal therapy, were considered against Candida spp. and Fusarium spp.

Methodology. The MICs of compound PH151 ranged from 1.0 to 16.0 µg ml−1, according to CLSI protocols.

Results. The association of PH151 with AMB and VRC showed a synergistic effect for more than 50% of the strains tested.

Conclusion. Both the compound alone and its association (VRC-AMB-PH151) demonstrated promising potential as an antifungal agent in ocular infections, since the evaluated ocular toxicity profile was positive and the compounds presented low toxicity.

Introduction. Bloodstream infections (BSIs) are one of the most serious infections investigated by microbiologists. However, the time to detect a BSI fails to meet the rapidity required to inform clinical decisions in real time.

Gap Statement. Blood culture (BC) is considered the gold standard for diagnosing bloodstream infections. However, the time to blood culture positivity can be lengthy. Underpinning this is the reliance on bacteria replicating to a high concentration, which is necessary for the detection using routine blood culture systems. To improve the diagnosis and management of patients with BSIs, more sensitive detection methods are required.

Aim. The study aimed to answer key questions addressing the delay in BSI detection and whether the time to BSI detection could be expedited using a Scattered Light Integrated Collection (SLIC) device.

Methodology. A proof-of-concept study was conducted to compare the time to positivity (TTP) of Gram-negative BCs flagging positive on BacT/ALERT with an SLIC device. An SLIC device was utilized to compare the TTP of the most prevalent BSI pathogens derived from nutrient broth and BC, the influence of bacterial load on TTP and the TTP directly from whole blood. Additionally, the overall turnaround time (TAT) of SLIC was compared with that of a standard hospital workflow.

Results. Most pathogens tested took significantly longer to replicate when derived from BC than from nutrient medium. The median TTP of Gram-negative BC on BacT/ALERT was 13.56 h with a median bacterial load of 6.4×109 c.f.u. ml−1. All pathogens (7/7) derived from BC at a concentration of 105 c.f.u. ml−1 were detectable in under 70 min on SLIC. Decreasing Escherichia coli BC concentration from 105 to 102 c.f.u. ml−1 increased the TTP of SLIC from 15 to 85 min. Direct BSI detection from whole blood on SLIC demonstrated a 76% reduction in TAT when compared with the standard hospital workflow.

Conclusion. An SLIC device significantly reduced the TTP of common BSI pathogens. The application of this technology could have a major impact on the detection and management of BSI.

Introduction. Shiga toxin-producing Escherichia coli (STEC) infections are of public health concern as STEC can cause large national foodborne outbreaks of severe gastrointestinal disease, particularly in the young and elderly. In recent years, the implementation of PCR by diagnostic microbiology laboratories has improved the detection of STEC, and there has been an increase in notifications of cases of non-O157 STEC. However, the extent this increase in caseload can be attributed to the improved detection by PCR, or a true increase in non-O157 STEC infections, is unknown.

Gap Statement. Epidemiological and microbiological data and analyses describing the trends in non-O157 STEC in England since the implementation of PCR are limited.

Aim. Demographic, microbiological and clinical characteristics of non-O157 STEC from 8 years (2016–2023) of laboratory surveillance data were analysed to understand the recent trends in non-O157 serotypes and the incidence of disease in England.

Methodology. All human isolates of STEC non-O157 detected between 2016 and 2023 were extracted from the laboratory surveillance system. Microbiological data were analysed and linked to clinical outcomes.

Results. There was an almost 10-fold increase in diagnoses of non-O157 STEC from 2016 (n=297) to 2023 (n=2341). A total of 9378 isolates of non-O157 STEC were detected, comprising 338 different serotypes, and were linked to 9311 individuals. A higher proportion of non-O157 STEC cases were female (56%) and aged between 20 and 39 years (27%). The most common non-O157 serotypes were O26:H11 (16%), O146:H21 (12%), O91:H14 (11%), O128:H2 (6%), O145:H28 (5%) and O103:H2 (4%). STEC O26:H11 was more frequently reported in under 5s than any other age group (38%), whereas the other common serotypes were more frequently isolated from adults. Stx2a, which has been associated with greater disease severity, was detected in 18% of cases. Where clinical details were available, 27% of non-O157 cases were admitted to the hospital and 6% developed HUS. Cases of STEC O145:H28 reported a higher rate of hospitalisation than other non-O157 STEC cases. The serotypes most likely to be associated with progression to HUS were O26:H11 (9%) and O145:H28 (7%). STEC harbouring stx2f (19%), stx2a (11%) and stx2d (11%) were most frequently isolated from cases with HUS.

Conclusion. The implementation of widespread PCR testing in England has facilitated better surveillance of STEC non-O157, with respect to establishing the true incidence and burden of disease of non-O157 STEC and monitoring the emergence of highly virulent strains.

Introduction. Apolipoprotein E (ApoE), especially the ApoE4 isotype, is suggested to influence the severity of respiratory viral infections; however, this association is still unclear.

Hypothesis. The presence of allele ε4 impacts the development of flu-like syndromes.

Aim. This study aimed to evaluate the impact of the Apo E4 isoform on the severity and duration of flu-like syndromes, including the coronavirus disease COVID-19.

Methodology. This study comprised 280 individuals presenting flu-like symptoms, all genotyped for ApoE isoforms. Data were collected on clinical course, comorbidities, nutritional status, biochemical and inflammatory markers, SARS-CoV-2 reverse transcription PCR results and disease severity (mild, moderate or severe) according to the World Health Organization criteria. The individuals were analysed as a whole and within subgroups based on the SARS-CoV-2-positive (COVID-19 group) or SARS-CoV-2-negative (flu-like syndrome group) test.

Results. The frequency of the ε4 allele was similar across the whole population and in both the COVID-19 and flu-like syndrome subgroups (17 and 18%, respectively). No differences were seen in sex, age range, self-reported skin colour, body mass index (BMI), number of comorbidities, vaccination status, biochemical, cytokine and lipid profiles (except for total cholesterol) in the flu-like group when ε4 allele carriers and non-carriers were compared. In the COVID-19 group, the ε4 allele did not correlate with disease severity or duration, number of comorbidities or inflammatory biomarkers. While gender distribution was equal in the overall COVID-19 population, male gender strongly correlated with COVID-19 severity. Multivariate analysis showed that older individuals, male gender, higher BMI and the presence of comorbidities were linked to increased chances of developing moderate and severe disease. IL-4 was the only factor found to reduce the risk of severe COVID-19.

Conclusion. The presence of one ɛ4 allele showed no association with the duration and severity of flu-like syndromes, including COVID-19. Nonetheless, SARS-CoV-2-positive individuals tend to be older men with a higher BMI and a tendency to be overweight or with obesity. Regarding COVID-19 severity, BMI, male sex and the number of associated comorbidities were the factors that increased the chance of developing a more severe form of COVID-19.

Introduction. Immediate identification of travellers’ diarrhoea-causing pathogens may not be possible in remote settings, but samples can be stored for epidemiological and related research. We collected pilot data to evaluate the utility of three different preservation media for testing stored faecal samples compared to immediate testing of fresh samples using the BioFire® FilmArray® multiplex PCR gastrointestinal panel (bioMérieux).

Gap statement. No previous studies have demonstrated the utility of testing faecal samples directly by PCR BioFire® FilmArray® following prolonged storage and transportation in OMNIgene®, DNA™ shield and FTA™ cards.

Aims. To evaluate the reliability of OMNIgene®, DNA shield™ and FTA™ card faecal storage and transport media in parallel, compared to initial testing of fresh faeces obtained from the same individuals at the time of presentation with diarrhoea in the field compare the results of faecal samples stored and transported at ambient temperature in OMNIgene®, DNA shield™ and FTA™ cards then tested using PCR BioFire® FilmArray® 6–18 months later with those obtained from fresh faecal samples during a diarrhoea outbreak.

Methodology. Fresh faecal samples were obtained from British military personnel who developed diarrhoea during deployment to Kenya between February-April 2022. Unpreserved fresh samples were tested onsite using PCR BioFire® FilmArray® and corresponding samples were stored at ambient temperature in OMNIgene®200 (DNAgenotek®), DNA/RNA shield DX™ (Zymo Research) and Whatman FTA™ Elute cards (GE Healthcare) then repatriated to the UK for direct testing by PCR BioFire® FilmArray®, 6-18 months later. The most common enteropathogens evaluated were: Cryptosporidium spp., Enteroaggregative Escherichia coli (E. coli; EAEC), Enteropathogenic E. coli (EPEC), Shiga toxin-producing E. coli (STEC) and Campylobacter spp. Test results for the three storage modalities were compared to the fresh sample tests as a reference standard.

Results. Samples from 60 individuals [80% male; median (interquartile range) age 24 (22–28) years] were analysed. Test sensitivity for Campylobacter spp. and EAEC was high across all three storage modalities (86.4–100%). OMNIgene®200 and DNA/RNA shield™ showed significant concordance with the reference standard test for other pathogens, but FTA™ Elute card tests had low sensitivity for STEC and poor specificity for Campylobacter spp. Agreement between FTA™ Elute cards and the reference standard test was low-moderate (kappa coefficient ≤0–0.49) for all enteropathogens.

Conclusions. This study demonstrates successful PCR BioFire® FilmArray® utility in testing samples stored in different media and is the first to compare the use of OMNIgene®200, DNA/RNA shield™ and FTA™ Elute cards simultaneously with the results of clinical samples. Stored samples were tested up to 18 months later with significant concordance observed in OMNIgene®200 and DNA/RNA shield™ compared to reference standard testing. The distorted performance of FTA™ Elute card testing requires further optimisation. Testing of samples stored in these media is suitable for research studies, but their applicability with other molecular diagnostic platforms, or clinical diagnostics, requires confirmation.

Introduction. Fungal infections caused by yeast have increased in recent decades, becoming a major threat to public health.

Hypothesis/Gap Statement. Antifungal therapy represents a challenging problem because, in addition to presenting many side effects, fungal resistance has been increasing in recent years. As a result, the search for new therapeutic agents has advanced with the use of new technologies such as nanoparticles (NPs).

Aim. Synthesize, characterize and evaluate the antifungal potential of naringenin (NAR)-stabilized silver NPs.

Methodology. The biosynthesis of NPs was stabilized using the NAR molecule and an aqueous solution of silver nitrate. The characterization of silver nanoparticles (AgNPs) was performed using different methods, which include UV-visible spectroscopy, powder X-ray diffraction (XRD), transmission electron microscopy, zeta potential measurements and Fourier transform infrared (FTIR) spectroscopy. Antifungal activity was evaluated against clinical isolates of Candida albicans by determining the MIC and the minimum fungicidal concentration (MFC).

Results. The AgNP NAR showed a colloidal appearance with an average size of 14.71 nm and zeta potential measured at −33.3 mV, indicating a highly stable suspension. XRD analysis confirmed the crystal structure. FTIR spectra showed the presence of several functional groups of plant compounds, which play an important role in the coating and bioreduction processes. The antifungal activity against C. albicans showed an MIC of 3.55 µg ml−1 and an MFC of 7.1 µg ml−1. According to the growth kinetic assay in 12 h, there was a reduction of ~50% (<3 log10). Furthermore, AgNP NAR did not show mutagenic potential.

Conclusion. The AgNP NAR obtained presented ideal characteristics for biomedical applications, good stability and promising antimicrobial activity.

Introduction. Diarrhoeagenic Escherichia coli (DEC) pathotypes are defined by genes located on mobile genetic elements, and more than one definitive pathogenicity gene may be present in the same strain. In August 2022, UK Health Security Agency (UKHSA) surveillance systems detected an outbreak of hybrid Shiga toxin-producing E. coli/enterotoxigenic E. coli (STEC–ETEC) serotype O101:H33 harbouring both Shiga toxin (stx) and heat-stable toxin (st).

Gap statement. These hybrid strains of DEC are a public health concern, as they are often associated with enhanced pathogenicity. However, little is known about their epidemiology, clinical significance and associated public health burden.

Aim. The aim of this study was to describe the microbiology, epidemiology and genomic analysis of this novel hybrid serotype in the context of the STEC–ETEC strains in the UKHSA archive.

Methodology. From 2014 to 2023, STEC isolated from faecal specimens testing positive for STEC by PCR were sequenced on the NextSeq 1000 short read platform and a subset were selected for long read nanopore sequencing. Genomes were analysed to determine serotype, stx subtype, DEC pathogenicity genes and antimicrobial resistance determinants.

Results. There were 162 STEC–ETEC strains isolated between 2014 and 2023, of which 117/162 were human clinical isolates and 45 were of food or animal origin. An average of 16 STEC–ETEC strains were identified each year, exhibiting a range of different stx subtypes, the most common profiles being stx2g,st (n=65, 40%) and stx2a,st (n=48, 30%). The most common sequence types were ST329 and ST200 (n=24 each), and the most frequently detected serotype was O187:H28 (n=25). Nine cases of genetically linked STEC–ETEC O101:H33, stx1a,st were detected between 8 August and 21 September 2022. Although the temporal and geographical distribution of the cases was characteristic of a foodborne outbreak, the contaminated vehicle was not identified.

Conclusions. Phylogenetic analysis and long-read sequencing of the outbreak strain provided insight into the stepwise acquisition of st and stx and the evolutionary history of STEC–ETEC pathotypes. The integration of epidemiological data and whole-genome sequencing for routine surveillance of gastrointestinal pathogens is key to understanding the emergence of zoonotic hybrid DEC pathotypes and monitoring foodborne threats to public health.

Staphylococcus epidermidis is frequently isolated during prosthetic joint infections (PJIs). Unlike Staphylococcus aureus, its internalization and persistence within cells are controversial. We aimed to determine whether internalization is involved in the pathophysiology of S. epidermidis PJIs. Adhesion and internalization of S. epidermidis PJI isolates have been studied using an in vitro model. Despite similar adhesion levels to the S. aureus SH1000 reference strain, S. epidermidis isolates had a low internalization in osteoblasts, synoviocytes and endothelial cells. Internalization of S. epidermidis is strain- and cell-type dependent. Our results do not support S. epidermidis internalization as a key factor in PJIs.

Introduction. Cold atmospheric plasma (CAP) has emerged as a promising technology for neutralizing microbes, including multidrug-resistant strains. This study investigates CAP’s potential as an alternative to traditional antimicrobial drugs for microbial inactivation.

Hypothesis/Gap Statement. In the era of increasing antimicrobial resistance, there is a persistent need for alternative antimicrobial strategies. CAP exerts its effects by generating reactive oxygen and nitrogen species (RONS), but its comparative efficacy against antimicrobial drugs requires further exploration.

Aim. To evaluate the antimicrobial efficacy of CAP in inactivating multidrug-resistant Escherichia coli (ATCC BAA-2469), Staphylococcus aureus (MTCC 96) and Candida albicans (MTCC 227) and to compare its effectiveness with standard antimicrobial drugs.

Methodology. CAP, produced by an indigenously developed dielectric barrier discharge (DBD) setup comprising a quartz-glass-covered high-voltage electrode and a grounded stainless steel mesh electrode, was used to treat three pathogenic samples with varying treatment times (0–60 s). The zone of inhibition (ZoI; zone where microbes cannot grow) induced by CAP was compared with the ZoI of selected antimicrobial drugs (5–300 mcg). Scanning electron microscopy (SEM) analysed morphological changes, while optical emission spectroscopy (OES) detected RONS generated during treatment. Growth curve analysis assessed CAP’s impact on microbial growth, and statistical analysis compared CAP-induced ZoI with drug-induced ZoI.

Results. CAP treatment produced substantial ZoI against E. coli, S. aureus and C. albicans, with the largest ZoI (1194±35.35 mm²) in C. albicans after 60 s. DBD–CAP showed equivalent or superior efficacy compared with selected antimicrobial drugs based on ZoI comparisons. SEM revealed extensive cellular damage in all three pathogens, with visible morphological disruption within 60 s. Growth curve analysis showed a significant delay in microbial proliferation with increasing CAP exposure, effectively inhibiting growth over 24 h. OES confirmed the presence of RONS-related molecular bands [N2(C–B), N2 +(B–X) and OH(A–X)] and atomic O lines in the CAP.

Conclusion. CAP treatment exhibits equivalent or superior antimicrobial activity compared to selected antimicrobial drugs. CAP treatment exerts effects by inactivating pathogens, disintegrating cellular morphology and delaying microbial growth. These findings highlight CAP as a promising alternative to prolonged treatments, addressing antimicrobial resistance and advancing clinical strategies.