High Bacterial Load Research Articles

Clinical case report of non-surgical and surgical endodontic treatment (apicoectomy)

Endodontic treatment, both non-surgical and surgical, aims to eliminate the neurovascular bundle and the microbiota present within the root canal system and the extraradicular region. This study reports the clinical management of a 31-year-old female patient with odontalgia in tooth #46. Following clinical and radiographic evaluation, a periapical radiolucent lesion approximately 5 mm in diameter was identified. Initially, conventional endodontic treatment was performed using the Reciproc Blue mechanized system, followed by an apicoectomy due to persistent symptoms associated with a high bacterial load. The therapeutic approach was based on the review of 12 scientific articles to establish an accurate pulp and periapical diagnosis and to select appropriate techniques and materials. Treatment outcomes demonstrated adequate healing and periapical repair, with resolution of clinical symptoms and functional improvement of the treated tooth. It is concluded that the integration of non-surgical and surgical treatments is essential in cases of pulp necrosis and chronic periapical abscess with high bacterial load. This complementary approach optimizes therapeutic outcomes, preserves the tooth, and improves the patient’s quality of life

Microbiological indoor air quality and associated factors in private clinics of Harar Town, Eastern Ethiopia

Background: Indoor air pollution, including airborne microorganisms, can cause allergies, respiratory diseases, and immune-toxic diseases. Sneezing generates millions of airborne microbial infections, and ventilation sources alter microbial communities. Few studies exist in developing countries, including Ethiopia, and Harar Town. The aim is to assess microbial indoor air quality and associated factors among private clinics, Harar town, Eastern Ethiopia. Methodology: A cross-sectional study was conducted on 260 private clinic rooms in Harar town, using a systematic random sampling method and passive air sampling. Data was collected using the settle plate method and an observation checklist. Bivariate and multivariate analysis was performed using binary logistic regression, with a P-value of <0.05 considered statistically significant. Result: The minimum and maximum bacterial loads were 3933 CFU/m3 and 92 CFU/m3 respectively. Based on the pollution degree of the European Commission, the Mean bacterial load (904 CFU/m3) was at higher bacterial load. The highest, lowest, and mean fungal loads were 1967 CFU/m3, 9 CFU/m3 and 401 CFU/m3 respectively. Temperature of <25 °C (AOR = 1.58, p = 0.04, and 95% CI = 1.05, 1.91), >28 °C (AOR = 1.23, P = 0.03, and 95% CI = 1.51, 2.02) were significantly associated with bacterial indoor air quality. Relative humidity of treatment rooms (AOR = 1.87, p = 0.02, and 95% CI = 1.21, 3.09) had an association with bacterial loads. The clinic treatment rooms with a recorded temperature <25 °C (AOR = 6.32, p = 0.01, and 95% CI = 6.10, 8.25) had associated with fungal loads. But the rooms having a temperature of >28 °C (AOR = 0.41, p = 0.04, and 95% CI = 0.31, 0.78) were 59% less likely to comply with the fungal standards compared to rooms having a temperature of 25–28 °C. The clinic rooms with a relative humidity of <30% (AOR = 7.75, p = 0.02, 95% CI = 7.21, 8.39) were 7.75 times more likely to comply with those with a relative humidity of > 60% in the treatment rooms. Conclusion: Private clinics in Harar had a moderate fungal load and a higher indoor air bacterial concentration when compared to different indoor air standards. Temperature, humidity, inadequate ventilation and the presence of unsanitary attached toilets are some variables associated with microbial loads.

Characterization and functional analysis of a novel goose-type lysozyme from teleost Sebastes schlegelii with implications for antibacterial defense and immune cell modulation.

Lysozymes are crucial enzymes involved in the innate immune response against bacterial pathogens. In this study, we identified and characterized a goose-type lysozyme gene (SsLyG) from the black rockfish Sebastes schlegelii, an economically important aquaculture species. The deduced amino acid sequence of SsLyG contains 495 residues, which inculded a signal peptide, an immunoglobulin domain, and a goose egg-white lysozyme (GEWL) domain. Tissue expression analysis revealed the highest SsLyG levels in blood, and its transcription was significantly upregulated in the spleen and kidney upon bacterial and polyI:C challenges. Recombinant SsLyGE (rSsLyGE) exhibited lytic activity against Micrococcus lysodeikticus and concentration-dependent binding ability to Staphylococcus aureus and Micrococcus luteus. Furthermore, rSsLyGE promoted peripheral blood lymphocyte proliferation, enhanced macrophage respiratory burst activity, and increased reactive oxygen species production. RNA interference-mediated knockdown of SsLyG resulted in higher bacterial loads in the liver and spleen after Listonella anguillarum challenge, suggesting its role in early antibacterial defense. Collectively, these findings provide insights into the immune function of SsLyG and its potential application in developing antimicrobial strategies for aquaculture.

Approaching the sterile womb theory in dogs and cats: A multi-technique investigation

The study investigated whether bacterial seeding occurs in utero in dogs and cats using a multi-technique approach, including 16S rRNA gene sequencing, culture, and fluorescence in situ hybridization (FISH). Healthy pregnant bitches and queens (n = 8) undergoing ovariohysterectomy between 30 and 45 days of gestation were included. Placenta and amniotic fluid samples from two foetuses per dam, along with multiple controls (uterine serosa, sampling table, and surgeon's gloves), were collected and analysed.Bacterial sequences were detected in all foetal samples, with no significant differences in intra- and inter-sample diversity (i.e., alpha and beta diversities, respectively) based on sample type or species. However, the surgeon's gloves showed species-specific differences in bacterial composition. After removing control sequences, significant differences based on foeto-maternal units emerged. Moraxella spp. was cultured from the canine placenta with the highest bacterial load, and Burkholderia cepacia was isolated from two feline placentae. FISH showed low bacterial presence in 50 % of placentae without histological signs of inflammation. No bacterial growth was observed in amniotic fluid or control samples.A multi-technique approach, including multiple controls, is essential in studies involving low-biomass samples, as the results of the present study indicated that contamination could mask real bacterial composition of foetal samples. After decontamination, differences were observed based on the foeto-maternal unit.This study confirmed the presence of bacterial DNA in placental and amniotic fluid samples during mid-term, healthy pregnancies in dogs and cats. Bacterial DNA is not equivalent to living bacteria, hence bacterial DNA fragments in the uterus probably originate from the dam but are unlikely to indicate the presence of a resident foetal microbiome.

Bacterial contamination of autologous blood salvaged during deceased donor liver transplantation: a prospective observational study.

Decompensated cirrhotic patients experience severely increased intestinal permeability and bacterial translocation. Thus, autologous blood salvaged during deceased donor liver transplantation (DDLT) may be contaminated with enteric bacteria. We aimed to evaluate bacterial contamination of autologous blood salvaged during DDLT and its association with post-transplant bacteremia. In 30 patients undergoing DDLT, bacterial culture was performed in salvaged autologous blood samples: one before graft reperfusion (non-leukoreduced) and two after graft reperfusion (non-leukoreduced and leukoreduced). The primary outcome was bacterial contamination of salvaged autologous blood. Seven of 30 patients (23.3%) were positive for bacteria (3 enteric/4 non-enteric) before graft reperfusion while 11 patients (36.7%) were positive (5 enteric/6 non-enteric) after graft reperfusion. Six of 7 patients who were positive for bacteria before graft reperfusion were positive after graft reperfusion with the same bacteria. Only 4 of 11 contaminated blood samples were converted to negative after leukoreduction. Post-transplant bacteremia risk was insignificantly greater in patients who received autologous blood with bacteria than in patients without bacteria (30.0% vs. 5.0%, P = 0.06). We found contamination of salvaged autologous blood with enteric bacteria throughout DDLT and incomplete performance of leukoreduction, indicating high bacterial load. The potential association between contaminated autotransfusion and post-transplant bacteremia warrants further validation in a larger prospective study.Clinical trial notation: This study was registered at the Clinical Research Information Service (CRiS; https://cris.nih.go.kr ; No. KCT0007223; principal registration investigator: Sangbin Han, date of registration: April 25, 2022).

Addressing underestimation of waterborne disease risks due to fecal indicator bacteria bound in aggregates.

This study aims to identify and address significant limitations in current culture-based regulatory methods used for monitoring microbiological water quality. Specifically, these methods' inability to distinguish between planktonic forms and aggregates containing higher bacterial loads and associated pathogens may lead to a severe underestimation of exposure risks, with critical public health implications. We employed a novel methodology combining size fractionation with ALERT, an automated rapid method for comprehensive quantification of culturable fecal indicator bacteria (FIB). Our findings reveal a substantial and widespread presence of aggregate-bound indicator bacteria across various water matrices and geographical locations. Comprehensive bacterial counts consistently exceeded those obtained by traditional methods by significant multiples, such as an average of 3.4×at the Seine River 2024 Olympic venue, and occasionally up to 100×in irrigation canals and wastewater plant effluent. These results, supported by microscopic and molecular analyses, underscore a systematic bias in global water safety regulatory frameworks. Our research demonstrates the inadequacy of traditional culture-based techniques in assessing microbiological risks posed by aggregate-bound FIB and associated pathogens, particularly in water matrices affected by FIB-rich fecal particles from recent sewer overflows or sediment, which can carry higher infectious risks. Incorporating comprehensive FIB analysis techniques, including molecular methods and rapid culture-based approaches as shown in this study, offers a promising and effective solution to these risk assessment limitations.

Refining the gut colonization Zophobas morio larvae model using an oral administration of multidrug-resistant Escherichia coli

BackgroundThe darkling beetle Zophobas morio can be implemented as an alternative in vivo model to study different intestinal colonization aspects. Recently, we showed that its larvae can be colonized by multidrug-resistant Escherichia coli strains administered via contaminated food (for 7 d) for a total experimental duration of 28 d. MethodIn the present work, we aimed to shorten the model to 14 d (T14) by administering the previously used CTX-M-15 extended-spectrum β-lactamase-producing ST131 E. coli strain Ec-4901.28 via a single oral administration (5 µL dose of 108 CFU/mL), using a blunt 26s-gauge needle connected to a 250 μL gastight syringe. Force-feeding was performed either without or with (larvae placed on ice for 10 min before injection) anaesthesia. In addition, phage-treated larvae were orally injected with 10 µL of INTESTI bacteriophage cocktail (∼105–6 PFU/mL) on d 4 (T4) and 7 (T7). ResultsGrowth curve analyses showed that, while larvae rapidly became colonized with Ec-4901.28 (T1, ∼106–7 CFU/mL), only those anaesthetized maintained a high bacterial load (∼102–3 vs. ∼105–6 CFU/mL) and survival rate (76% vs. 99%; P < 0.001) by T14. Moreover, bacteriophage administration to anaesthetized larvae significantly reduced the bacterial count of INTESTI-susceptible Ec-4901.28 at T14 (5.17 × 105 vs. 2.26 × 104, for non-treated and phage-treated larvae, respectively; P = 0.04). ConclusionsThe methodological refinements applied to establish the intestinal colonization model simplify the use of Z. morio larvae, facilitate prompt evaluation of novel decolonization approaches and reduce experiments involving vertebrate animals in accordance with the Replacement, Reduction and Refinement principles.

Integrated omics analysis reveals the effect of feeding scarcity on the lipid metabolism and apoptosis in Nibea coibor

Food scarcity was a crucial challenge to fish in natural waters, necessitating a complex adaptive process for them to cope with. This study estimated the effects of four different feeding strategies (daytime feeding, DF; intermittent fasting, IF; continuous fasting, CF; nighttime feeding, NF) on the growth, metabolism, and health of Nibea coibor. The lowest weight gain rate and steatosis degree occurred in the CF group, which had the highest bacterial load in the liver and the lowest survival rate after Vibrio harveyi infection. The IF group had the highest serum GLU, LAC, and COR levels and the lowest hepatic bacterial loads post V. harveyi challenge. The NF group had higher serum GLU level (P < 0.05) and lower survival rate compared to DF. Notably, the integrated analysis of transcriptome and metabolome screened out significantly differential genes (dgke, pla2g12b, axin2) and metabolite (Glycerophosphocholine), which were all involved in lipid metabolism and downregulated in CF (P < 0.05). The correlation analysis of phenotypic indicators with the transcriptome and metabolome showed that gadd45 and l-carnitine were positively and negatively correlated with bacterial infection resistance, respectively. In general, this study suggested fasting influenced weight gain and bacterial infection resistance of N. coibor, through regulating genes and metabolites related to lipid metabolism and apoptosis, providing valuable reference significance on the impact of feeding rhythm on fish.

Molecular resistance of Ethambutol in clinical samples obtained from patients admitted to the health center in Ardabil province using MAS-PCR

Background. Global stop TB is a critical strategy which aims at reducing the incidence of tuberculosis to less than one case per one million people by 2050. To achieve this goal, it is necessary to establish a timely diagnosis of the disease, provide an effective treatment, and identify the drug-resistant strains. Therefore, this study aimed to identify the resistance to ethambutol in patients referred to Ardabil Health Center. Methods. In this descriptive cross-sectional study, 71 clinical samples were collected from the patients referred to Ardabil Health Center between 2017-2020. The samples were first examined adopting microscopic method, and then DNA was extracted using the boiling method. Specific primers and MAS-PCR technique were employed for identification of ethambutol resistance strains. Results. Out of 71 collected specimens, six samples were NTM (8.45%). Out of all the examined samples, 36 samples (50.7%) had embB306 gene mutation, of which three samples were NTM (total NTM resistance was 50%). Out of the samples identified as resistant to ethambutol, six samples had a low bacterial load as +1 (16.67%), eight samples had a moderate bacterial load as +2 (22.22%), and the rest had a high bacterial load as +3 (61.11%). Conclusion. In sum, the frequency of resistance to ethambutol was 50.7%, which was higher than that reported by previous similar studies. Furthermore, it was determined that the MAS-PCR method was a fast, cheap, and reliable method for identifying resistance to the first-line tuberculosis drugs such as ethambutol. Therefore, this method may have facilitated evaluating the resistance to other first-line drugs at the same time and preventing the spread of resistant strains in the community through early detection of the antibiotic resistance. Practical Implications. Our study results may have been useful in increasing the awareness among the physician and health care workers of the ethambutol resistance level in indigenous strains in Ardabil province.

Mycobacterium marinum MMAR_0267-regulated copper utilization facilitates bacterial escape from phagolysosome

The host limits Mycobacterium tuberculosis (Mtb) by enriching copper in high concentrations. This research investigates how Mtb escapes copper stress. The membrane protein encoded by Mtb Rv0102, when its homolog in M. smegmatis (MSMEG_4702) was knocked out, resulted in a fourfold decrease in intracellular copper levels and enhanced tolerance to elevated extracellular copper concentrations. Similarly, knockout mutants of its homolog in M. marinum (MMAR_0267) showed increased virulence in zebrafish and higher bacterial load within macrophages. In THP-1 cells infected with MMAR_0267 deletion mutants, the intracellular survival of these mutants increased, along with reduced THP-1 cell apoptosis. Deficiency in copper down-regulated the transcriptional level of the virulence factor CFP-10 in M. marinum, suppressed cytosolic signaling via the macrophage STING pathway, leading to decreased production of IFN-β and reduced cell apoptosis. In conclusion, these findings highlight the significant impact of copper on the survival and reproduction of mycobacteria, underscoring the importance of studying mycobacterial adaptation mechanisms in copper-rich environments.

Occurrence and antimicrobial resistance of Campylobacter jejuni isolated from poultry and hospitalized diarrheal patients in Pakistan

The leading human enteropathogen Campylobacter jejuni (C. jejuni) is recognized as a major public-health concern, due to emerging multidrug resistant (MDR) strains, and associated post-infectious complications. Therefore, the present study determined the occurrence of C. jejuni in diarrheal cases and poultry, in Khyber Pakhtunkhwa Province, Pakistan, and associated antimicrobial resistance patterns. In total, 840 samples were collected from clinical and different poultry sources between May 2019 to April 2020, to determine the occurrence, seasonal variations, bacterial loads in diverse poultry samples, age-related variations in human infections as well as associated antimicrobial resistance patterns of C. jejuni, highlighting its “One Health significance” at the human-food interface. Clinical samples (n = 240) from five age-groups of hospitalized diarrhoea patients, showed occurrence rate of 39 %, which peaked in the summer and was highest in children under 5. In poultry samples, 57 % (342/600) were positive for C. jejuni, varied from 45 % (109/240) in chicken meat to 65 % (233/360) in farm samples. Except frozen meat, C. jejuni-positive poultry samples showed seasonal contamination levels, with summer having the highest bacterial loads. In chicken meat, 2 % of positive samples (2/109) had bacterial loads <1 logCFU/g, while 20 % (22/109) exceeding 3log CFU/g. Grocery store samples showed lower bacterial contamination. All human and poultry isolates (n = 436) were resistant to nalidixic acid (100 %) and none to amikacin (0 %). Of these, 66 % showed multidrug resistance, with 9 % (38/436) resistant to panel of seven out of eight antibiotics tested. This study highlights the high occurrence of and concerns about MDR C. jejuni in Khyber Pakhtunkhwa, Pakistan, particularly in young children.

Current vaccination strategy against Piscirickettsia salmonis in Chile based only on the EM-90 genogroup shows incomplete cross-protection for the LF-89 genogroup

Piscirickettsia salmonis, the primary bacterial disease in Chilean salmon farming, necessitates a constant refinement of control strategies. This study hypothesized that the current vaccination strategy for SRS control in the Chilean Atlantic salmon aquaculture industry, which has been in place since 2017 (ALPHA JECT® 5.1 plus LiVac®), solely relies on vaccines formulated with the EM-90 genogroup of P. salmonis (PS-EM-90), triggering a partial cross-immunity response in fish infected with the LF-89 genogroup (PS-LF-89). Relative Percent Survival (RPS) and cell-mediated immune (CMI) response were evaluated in Atlantic salmon post-smolts vaccinated with the standard vaccination strategy but challenged with both PS-EM-90 and PS-LF-89, in addition to other vaccination strategies considering primo vaccination and booster with other commercial vaccines and the possible enhancing effects of the combination with a natural immunomodulator (PAQ-Xtract®) administered orally. The intraperitoneal (I.P.) challenge was performed after 2395°-days (DD) after the start of the immunostimulant delivery, 1905 DD after the primo vaccination, and 1455 DD after the booster vaccination. Unvaccinated fish showed 73.6 and 41.7 % mortality when challenged with PS-EM-90 and PS-LF-89, respectively. Fish infected with PS-LF-89 died significantly faster (21 days post-infection, dpi) than fish challenged with PS-EM-90 (28 dpi) (p = 0.0043) and had a higher probability of death (0.4626) than fish challenged with PS-EM-90. RPS had a significant positive correlation with the PS-EM-90 load of the P. salmonis genogroup (r = 0.540, p < 0.01) but not with the PS-LF-89 load (r = 0.155, p > 0.05). This demonstrated that the immunization strategies were more effective in lowering PS-EM-90 loads, resulting in higher survival rates in fish challenged with PS-EM-90. The current industry vaccination strategy recorded a 100 % RPS when fish were challenged with PS-EM-90, but the RPS dropped significantly to 77 % when fish were challenged with PS-LF-89, meaning that the strategy did not show complete cross-protection. But after adding PAQ-Xtract®, the RPS improved from 77 % to 92 % in fish that were vaccinated with the standard method but then challenged with PS-LF-89. The most effective vaccination strategy was based on LiVac® as primo vaccination and ALPHA JECT® 5.1 plus LiVac® as booster vaccination, with or without PAQ-Xtract®, in both PS-EM-90 (100 %) and PS-LF-89 (96 %) challenged fish. The serum concentration of anti-P. salmonis IgM did not show a correlation with the protection of immunization strategies expressed in survival. Low serum IL-12 and high serum IFNγ concentrations showed a correlation with higher bacterial loads and lower survival. Aggregate analysis showed a significant correlation between higher numbers of CD8+ cells in the head-kidney, higher fish survival, and a lower bacterial load. The immunization strategies were safe for fish and induced only mild microscopic lesions in the gut. Taken together, our results help to better understand the biological interaction between P. salmonis and post-smolt vaccinated Atlantic salmon to deepen the knowledge on vaccine-induced protection, CMI immune response, and cross-immunity applied to improve the current immunization strategy for SRS control in the Chilean salmon industry.

Enhance the Antimycobacterial Activity of Streptomycin with Ebselen as an Antibiotic Adjuvant Through Disrupting Redox Homeostasis.

Tuberculosis (TB) remains a major health threat worldwide, and the spread of drug-resistant (DR) TB impedes the reduction of the global disease burden. Ebselen (EbSe) targets bacterial thioredoxin reductase (bTrxR) and causes an imbalance in the redox status of bacteria. Previous work has shown that the synergistic action of bTrxR and sensitization to common antibiotics by EbSe is a promising strategy for the treatment of DR pathogens. Thus, we aimed to evaluate whether EbSe could enhance anti-TB drugs against Mycobacterium marinum (M. marinum) which is genetically related to Mycobacterium tuberculosis (Mtb) and resistant to many antituberculosis drugs. Minimum inhibitory concentrations (MIC) of isoniazid (INH), rifampicin (RFP), and streptomycin (SM) against M. marinum were determined by microdilution. The Bliss Independence Model was used to determine the adjuvant effects of EbSe over the anti-TB drugs. Thioredoxin reductase activity was measured using the DTNB assay, and its effects on bacterial redox homeostasis were verified by the elevation of intracellular ROS levels and intracellular GSH levels. The adjuvant efficacy of EbSe as an anti-TB drug was further evaluated in a mouse model of M. marinum infection. Cytotoxicity was observed in the macrophage cells Raw264.7 and mice model. The results reveal that EbSe acts as an antibiotic adjuvant over SM on M. marinum. EbSe + SM disrupted the intracellular redox microenvironment of M. marinum by inhibiting bTrxR activity, which could rescue mice from the high bacterial load, and accelerated recovery from tail injury with low mammalian toxicity. The above studies suggest that EbSe significantly enhanced the anti-Mtb effect of SM, and its synergistic combination showed low mammalian toxicity in vitro and in vivo. Further efforts are required to study the underlying mechanisms of EbSe as an antibiotic adjuvant in combination with anti-TB drug MS.

Association of Staphylococcus aureus Bacterial Load and Colonization Sites With the Risk of Postoperative S. aureus Infection.

The independent effects of extranasal-only carriage, carriage at multiple bodily sites, or the bacterial load of colonizing Staphylococcus aureus (SA) on the risk of developing SA surgical site infections and postoperative bloodstream infections (SA SSI/BSIs) are unclear. We aimed to quantify these effects in this large prospective cohort study. Surgical patients aged 18 years or older were screened for SA carriage in the nose, throat, or perineum within 30 days before surgery. SA carriers and noncarriers were enrolled in a prospective cohort study in a 2:1 ratio. Weighted multivariable Cox proportional hazard models were used to assess the independent associations between different measures of SA carriage and occurrence of SA SSI/BSI within 90 days after surgery. We enrolled 5004 patients in the study cohort; 3369 (67.3%) were SA carriers. 100 SA SSI/BSI events occurred during follow-up, and 86 (86%) of these events occurred in SA carriers. The number of colonized bodily sites (adjusted hazard ratio [aHR], 3.5-8.5) and an increasing SA bacterial load in the nose (aHR, 1.8-3.4) were associated with increased SA SSI/BSI risk. However, extranasal-only carriage was not independently associated with SA SSI/BSI (aHR, 1.5; 95% CI, 0.9-2.5). Nasal SA carriage was associated with an increased risk of SA SSI/BSI and accounted for the majority of SA infections. Higher bacterial load, as well as SA colonization at multiple bodily sites, further increased this risk.

16S rRNA amplicon sequencing and antimicrobial resistance profile of intensive care units environment in 41 Brazilian hospitals.

Infections acquired during healthcare setting stay pose significant public health threats. These infections are known as Healthcare-Associated Infections (HAI), mostly caused by pathogenic bacteria, which exhibit a wide range of antimicrobial resistance. Currently, there is no knowledge about the global cleaning process of hospitals and the bacterial diversity found in ICUs of Brazilian hospitals contributing to HAI. Characterize the microbiome and common antimicrobial resistance genes present in high-touch Intensive Care Unit (ICU) surfaces, and to identify the potential contamination of the sanitizers/processes used to clean hospital surfaces. In this national, multicenter, observational, and prospective cohort, bacterial profiles and several antimicrobial resistance genes from 41 hospitals across 16 Brazilian states were evaluated. Using high-throughput 16S rRNA amplicon sequencing and real-time PCR, the bacterial abundance and resistance genes presence were analyzed in both ICU environments and cleaning products. We identified a wide diversity of microbial populations with a recurring presence of HAI-related bacteria among most of the hospitals. The median bacterial positivity rate in surface samples was high (88.24%), varying from 21.62 to 100% in different hospitals. Hospitals with the highest bacterial load in samples were also the ones with highest HAI-related abundances. Streptococcus spp., Corynebacterium spp., Staphylococcus spp., Bacillus spp., Acinetobacter spp., and bacteria from the Flavobacteriaceae family were the microorganisms most found across all hospitals. Despite each hospital particularities in bacterial composition, clustering profiles were found for surfaces and locations in the ICU. Antimicrobial resistance genes mecA, bla KPC-like, bla NDM-like, and bla OXA-23-like were the most frequently detected in surface samples. A wide variety of sanitizers were collected, with 19 different active principles in-use, and 21% of the solutions collected showed viable bacterial growth with antimicrobial resistance genes detected. This study demonstrated a diverse and spread pattern of bacteria and antimicrobial resistance genes covering a large part of the national territory in ICU surface samples and in sanitizers solutions. This data should contribute to the adoption of surveillance programs to improve HAI control strategies and demonstrate that large-scale epidemiology studies must be performed to further understand the implications of bacterial contamination in hospital surfaces and sanitizer solutions.

Freshwater microalgae Nannochloropsis limnetica for the production of β-galactosidase from whey powder

This study investigated the first-ever reported use of freshwater Nannochloropsis for the bioremediation of dairy processing side streams and co-generation of valuable products, such as β-galactosidase enzyme. In this study, N. limnetica was found to grow rapidly on both autoclaved and non-autoclaved whey-powder media (referred to dairy processing by-product or DPBP) without the need of salinity adjustment or nutrient additions, achieving a biomass concentration of 1.05–1.36 g L−1 after 8 days. The species secreted extracellular β-galactosidase (up to 40.84 ± 0.23 U L−1) in order to hydrolyse lactose in DPBP media into monosaccharides prior to absorption into biomass, demonstrating a mixotrophic pathway for lactose assimilation. The species was highly effective as a bioremediation agent, being able to remove > 80% of total nitrogen and phosphate in the DPBP medium within two days across all cultures. Population analysis using flow cytometry and multi-channel/multi-staining methods revealed that the culture grown on non-autoclaved medium contained a high initial bacterial load, comprising both contaminating bacteria in the medium and phycosphere bacteria associated with the microalgae. In both autoclaved and non-autoclaved DPBP media, Nannochloropsis cells were able to establish a stable microalgae–bacteria interaction, suppressing bacterial takeover and emerging as dominant population (53–80% of total cells) in the cultures. The extent of microalgal dominance, however, was less prominent in the non-autoclaved media. High initial bacterial loads in these cultures had mixed effects on microalgal performance, promoting β-galactosidase synthesis on the one hand while competing for nutrients and retarding microalgal growth on the other. These results alluded to the need of effective pre-treatment step to manage bacterial population in microalgal cultures on DPBP. Overall, N. limnetica cultures displayed competitive β-galactosidase productivity and propensity for efficient nutrient removal on DPBP medium, demonstrating their promising nature for use in the valorisation of dairy side streams.

Assessment of Conservation Status of Petroleuciscus Borysthenicus Celensis From Gurban River, Romania by Identification of Parasites and Bacteria

The present research was conducted within the framework of a broader investigation with the objective of identifying freshwater parasites and bacteria on national territory, with the aim of gaining a deeper understanding of the relationships between parasites, hosts, and the environment, and to assess the potential detrimental effects of parasitic infestation on the conservation status of fish populations. Within this study, it was documented the first recordings of parasites Vorticella globularia and Epistylis sp. in the Romanian Petro-leuciscus borysthenicus celensis fish species. A total of 42 specimens were collected from the Gurban River to study their infestation status, focusing on the skin, gills, and fins. From the samples analyzed, 16 specimens presented signs of infestation with five distinct parasite species (Ichthyophthirius multifiliis, Dactylogyrus vastator, Trichodina acuta, Vorticella globularia and Epistylis sp) and four bacterial strains (Aeromonas veronii, Shewanella putrefaciens, Aeromona hydrophila, and Citrobacter freundii). The results indicate that the skin is the organ most severely impacted by parasites and bacteria, followed by the gills. The fins, on the other hand, are the least susceptible to infection. Furthermore, the significant amount of parasitic infestation coupled with the high bacterial load of Aeromonas veronii indicates a plausible link between the two.

Surveillance of close contacts of patients with infectious tuberculosis: a prospective cohort study

BackgroundA long-term follow-up of close contacts to monitor their infection status is essential to formulate a promising screening strategy. The study aimed to assess the dynamics of tuberculosis (TB) infection using Interferon-γ release assay (IGRA) and determine risk factors associated with TB infection.MethodsDefinite TB patients were interviewed and their household contacts were screened for TB infection by IGRA during 12-month longitudinal investigation.ResultsWe included in our analyses 184 household contacts of 92 index TB patients. 87 individuals (47.3%) in contact group progressed to TB infection, of whom 86 developed into IGRA positive within 24 weeks. Close contacts with a higher age and comorbidities are easier to exhibit TB infection. Analysis showed that risk factors for becoming IGRA-positive individuals included residence, older age, comorbidities, BCG scar and high bacterial load. Contacts with BCG scar had a lower IGRA-positive rate.ConclusionIGRA conversion generally occurs within 24 weeks after exposure. The TB transmission happens since subclinical TB stage and the presence of BCG scar is an independent protective factor reducing risk of TB infection among close contacts. Repeated IGRA tests are sensible to conducted among close contacts at 24 weeks after exposure to identify the IGRA-positive individuals.

A blood-based 3-gene signature score for therapeutic monitoring in patients with pulmonary tuberculosis

ObjectiveTo assess the validity of Xpert Tuberculosis Fingerstick score for monitoring treatment response and analyze factors influencing its performance. Methods122 adults with pulmonary tuberculosis were recruited and stratified into three cohorts: Diabetic-drug-susceptible-TB (DM-TB), Non-diabetic-drug-susceptible-TB (NDM-TB) and Non-diabetic Multidrug-resistant TB (MDR-TB). Fingerstick blood specimens were tested at treatment initiation (M0) and the end of the first (M1), second (M2), and sixth month (M6) to generate a TB-score. ResultsThe TB-score in all participants yielded an AUC of 0.707 (95% CI: 0.579–0.834) at M2 when its performance was evaluated against sputum culture conversion. In all non-diabetes patients, the AUC reached 0.88 (95% CI: 0.756–1.000) with an optimal cut-off value of 1.95 at which sensitivity was 90.0% (95% CI: 59.6–98.2%) and specificity was 81.3% (95% CI: 70.0–88.9%). The mean TB score was higher in patients with low bacterial loads (n = 31) than those with high bacterial loads (n = 91) at M0, M1, M2, and M6, and was higher in non-cavitary patients (n = 71) than those with cavitary lesions (n = 51) at M0, M1, and M2. ConclusionXpert TB-score shows promising predictive value for culture conversion in non-diabetic TB patients. Sputum bacterial load and lung cavitation status have an influence on the value of TB score.

Bacteriological Analyses of Fish Mucus from Fish Market with Reference to Consumer’s Health

A study was conducted to evaluate the bacteria load present in fish mucus collected from Nanpura wholesale fish market during the period from 30th December 2022 to 20th February 2023. Total 20 fish mucus samples were determined by Total Plate Count (TPC) and identification of bacteria. High bacterial load with pathogens such as Escherichia coli (Gram negative bacteria) and Staphylococcus aureus (Gram positive bacteria) were found in all fresh and marine fish samples from study area. These pathogens can survive and multiply in fish, transferred into consumer by way of food and main source of fish poisoning, diarrhoea, meningitis and septicemia which cause health risk to consumer. The fishes were contaminated with pathogenic bacteria indicated poor handling of fishes, lack of preservation facility and unhygienic condition of study area. Thus, it is strongly recommended to improve the quality control and quality assurance systems of the study area to minimize the prevalence of pathogenic bacteria.