Concomitant Pathogens Research Articles

Bacterial and Viral Co-Infections in COVID-19 Patients: Etiology and Clinical Impact.

Mixed infections can worsen disease symptoms. This study investigated the impact of mixed infections with viral and bacterial pathogens in patients positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Using the in-house multiplex PCR method, we tested 337 SARS-CoV-2 positive samples for co-infections with three bacterial and 14 other viral pathogens. Between August 2021 and May 2022, 8% of 337 SARS-CoV-2-positive patients had bacterial co-infections, 5.6% had viral co-infections, and 1.4% had triple mixed infections. The most common causes of mixed infections were Haemophilus influenzae (5.93%) and respiratory syncytial virus (RSV) (1.18%). Children < 5 years old had more frequent co-infections than adults < 65 years old (20.8% vs. 16.4%), while adults showed a more severe clinical picture with a higher C-reactive protein (CRP) level (78.1 vs.16.2 mg/L; p = 0.033), a lower oxygen saturation (SpO2) (89.5 vs. 93.2%), and a longer hospital stay (8.1 vs. 3.1 days; p = 0.025) (mean levels). The risk of a fatal outcome was 41% in unvaccinated patients (p = 0.713), which increased by 2.66% with co-infection with two pathogens (p = 0.342) and by 26% with three pathogens (p = 0.005). Additionally, 50% of intensive care unit (ICU) patients had a triple infection, compared with only 1.3% in the inpatient unit (p = 0.0029). The risk of death and/or ICU admission was 12 times higher (p = 0.042) with an additional pathogen and increased by 95% (p = 0.003) with a third concomitant pathogen. Regular multiplex testing is important for prompt treatment and targeted antibiotic use.

Enteroaggregative Escherichia coli in mid-Norway: A prospective, case control study.

The use of molecular methods has led to increased detection of Enteroaggregative Escherichia coli (EAEC) in faecal samples. Studies have yielded conflicting results regarding the clinical relevance of this finding. The objective of this study was to investigate the prevalence of EAEC in faecal samples from patients with diarrhoea and healthy controls and describe characteristics of EAEC positive persons. From March 1st, 2017 to February 28th, 2019, we investigated all consecutive faecal samples from patients with diarrhoea received at the laboratory and collected faecal samples from randomly invited healthy controls from mid-Norway. Real-time multiplex PCR was used for detection of bacterial, viral, and parasitic pathogens. We registered sex, age, urban versus non-urban residency, and travel history for all participants. Statistical analyses were performed with Pearson chi-squared test, Kruskal-Wallis test, and Mann-Whitney U test. We identified EAEC in 440 of 9487 (4.6%) patients with diarrhoea and 8 of 375 (2.2%) healthy controls. The EAEC prevalence was 19.1% among those with diarrhoea and recent foreign travel and 2.2% in those without travel history independent of diarrhoea. Concomitant pathogens were detected in 64.3% of EAEC-positive patients with diarrhoea. The median age was 28.5 in those with EAEC-positive diarrhoea and 38 in those with EAEC-negative diarrhoea (p <0.01). In patients with diarrhoea, travel was reported in 72% of those with EAEC and concomitant pathogens, and 54% and 12% in those with only EAEC and no EAEC, respectively (p <0.01). EAEC was a common detection, particularly in patients with diarrhoea and recent international travel, and was found together with other intestinal pathogens in the majority of cases. Our results suggest that domestically acquired EAEC is not associated with diarrhoea. Patients with EAEC-positive diarrhoea and concomitant pathogens were young and often reported recent travel history compared to other patients with diarrhoea.

Combination with Annual Deworming Treatments Does Not Enhance the Effects of PCV2 Vaccination on the Development of TB in Wild Boar Populations.

Vaccination against PCV2 has been proven to be an effective measure to reduce the severity of TB in wild boar. The combination of this measure with strategies focused on treating other key concomitant pathogens, such as nematodes, could be a useful strategy. This study assesses whether a combination of deworming treatments and PCV2 vaccination may reduce the prevalence and severity of TB in wild boar. The study was conducted on five game estates in mid-western Spain where four groups of wild boar were produced: control, vaccinated, dewormed and vaccinated-dewormed. Wild boars from all groups were hunted between 2017 and 2020, and all of them received a TB diagnosis based on pathological and microbiological tests. Generalised linear models were used to explore the effect of deworming and PCV2 vaccination on TB prevalence and severity. PCV2-vaccinated animals showed lower probabilities of suffering severe TB lesions. However, no differences regarding TB severity were found between dewormed and non-dewormed wild boar. PCV2 vaccination reduces TB severity in wild boar. However, annual deworming does not produce a long-term parasitological reduction that can influence the development of TB in wild boar, nor does it improve the effect of PCV2 vaccination on TB.

Small-Dose Trimethoprim-Sulfamethoxazole Prevents Pneumocystis Jiroveci Pneumonia in B-Cell Lymphoma Patients Receiving Chemotherapy: Analysis of a Randomized Controlled Clinical Trial

B-cell lymphoma is the most common non-Hodgkin lymphoma and is usually treated with the R-CHOP regimen. However, some patients might develop interstitial pneumonitis (IP), which has led to death in some patients. With advances in detection techniques, infections are now considered to be an important etiologic factor in IP, particularly the common opportunistic causative agent Pneumocystis jiroveci. A retrospective cohort analysis at our center has tentatively elucidated that TMP-SMX can achieve effective IP prevention. There are no prospective studies to confirm the preventive effect of TMP-SMX and its mechanism. A single-arm, single-center, randomized controlled clinical trial of TMP-SMX for the prevention of interstitial pneumonitis was conducted at our center. Prophylactic treatment with TMP-SMX in patients in the treatment group was turned on immediately after starting chemotherapy and continued until one month after the end of chemotherapy. The dose of prophylactic treatment was 0.16 g of TMP/0.8 g of SMX once daily. From April 26, 2022, to July 25, 2023, a total of 198 patients with the diagnosis of B-cell lymphoma met the criteria for enrollment and were randomly assigned to the control and treatment groups. Eleven were lost to follow-up before completing 4 courses of chemotherapy, 19 did not complete 4 courses of chemotherapy as of July 25, 2023, and 3 were excluded from the evaluation when they were switched to chemotherapy with other regimens not based on R-CHOP because of poor efficacy after 1 course of chemotherapy, among other reasons. 80 patients in the treatment group and 85 in the control group were finally included in the assessment (Figure 1, Figure 2). There were no statistical differences between patients in the control and treatment group in terms of baseline clinical characteristics such as gender, age, smoking history, lung disease, type of pathology, Ann Arbor stage, LDH level, ECOG score, IPI score, chemotherapy regimen, and group B symptoms. Observation of the primary outcome events in this study showed a significant reduction in the incidence of IP (5.0% vs 47.1%, P&amp;lt;0.001) and PJP (0.0% vs 28.2%, P&amp;lt;0.001) in the patients in the treatment group (Figure 2). IP occurred in 4 (5.0%) in the treatment group, and retrospective patient characteristics revealed that all were COVID-19, in addition to no patients developing IP. Forty (47.1%) in the control group developed IP, 16 were COVID-19, and 24 patients had a complete bronchoscopy with alveolar lavage sent for NGS, all of which revealed PJs or concomitant other pathogens. As of July 25, 2023, 1 patient discontinued TMP-SMX because of the development of renal insufficiency. There have been no deaths due to PJP in patients enrolled in this clinical trial at our center. The results of the subgroup analyses showed that TMP-SMX prophylaxis in any subgroup significantly reduced the risk of IP and there was no interaction. Of the 44 patients who developed IP, 24 underwent bronchoscopy, and PJ was detected by alveolar lavage NGS in all of them, and other pathogens such as Streptococcus pneumoniae, human herpesvirus, Catamoeba, and Candida albicans were detected in some patients. The median number of chemotherapy cycles in which IP occurred was 4 (Figure 1). In the control group, between patients who developed IP and those who did not, there were statistically significant differences in LDH levels (IP 237.0 (194.5, 398.0) vs Non-IP 198.0 (161.0, 278.0), P=0.032), R-CDOP chemotherapy regimen (IP 67.5% vs Non-IP 42.2%, P=0.004) difference, and the rest of the factors did not differ between the two groups. Binary logistic regression analysis of risk factors for the development of IP in the control group showed that patients on the R-CDOP chemotherapy regimen had a significantly increased risk of IP (OR=2.72, 95% CI 1.09-6.80, P=0.033), whereas there was no significant difference between age and LDH. As the chemotherapy cycle progressed, the patients' CD4 + T-cell counts gradually decreased, with the same trend in the control group as in the treatment group. In patients receiving chemotherapy with R-CHOP/R-CDOP-based regimens, the majority of IP that occurs is PJP and prevention with TMP-SMX is safe and effective. Patients treated with PLD have a higher risk of IP occurrence.

First report of powdery mildew caused by Erysiphe corylacearum on hazelnut in Bulgaria.

In June 2020, during an observation of fruit-bearing hazelnut trees (Corylus avelana L., cv. Tonda Gentile), grown in a small private home garden in the region of Kavarna (North-Eastern Black Sea coast of Bulgaria), symptoms of powdery mildew were observed on each of the 15 trees. Compared to the widely spread in Bulgaria powdery mildew caused by Phyllactinia guttata and known with its powdery patches and differing chasmothecia exclusively formed on the abaxial leaf surface, the newly observed disease was characterized by the presence of concomitant pathogen's structures on both the abaxial and adaxial surfaces of the leaves, varying from single pustules to 90% severity on certain leaves, as well as on the husks which were 100% affected. Among the white mycelium, cylindrical conidiophores and singly produced conidia (22-34 x 16-22 µm; n = 50) were found. Scattered or in groups, black spherical chasmothecia (diameter of 85-115 µm; n = 30), possessing 8 to 12 appendages with dichotomous branched apices, were also observed in the autumn. Chasmothecia contained 3 to 5 subglobose asci (45-60 x 34-62 µm; n = 30), each ascus containing 8 hyaline and ellipsoid ascospores (15-22 x 9-16 µm; n = 50). From one field powdery mildew sample DNA was extracted using the Nucleospin Plant II kit (Macherey-Nagel, Germany) and the rDNA ITS region was amplified using primers PMITS1 and PMITS2 (Cunnington, J.H. et al., 2003). The amplicon was sequenced (Macrogen Europe, The Netherlands) and used in a BLAST analysis. This resulted in 100% homology with the ITS sequence of Erysiphe corylacearum. The obtained sequence was different from the ones of Erysiphe pseudocorylacearum (99.20% homology) and Erysiphe coryli-americanae (96.52% homology). The targeted sequence was submitted to GenBank (accession number OQ860748). Based on the symptoms, morphological characteristics and molecular identification, the pathogen was identified as Erysiphe corylacearum. Pathogenicity of the fungus was confirmed under lab conditions (natural day/light regime, 23-25°C) by shaking down conidia from naturally infected leaves on both sides of healthy leaves (2-years plantlets, cv. Tonda Gentile, 3 replicates) and incubation in a moist chamber (plastic bags) for the first 24 hours. First small fluffy white pustules appeared 6-7 days after inoculation, subsequently, the disease was progressing and the pathogen's conidiophores and conidia were morphologically identical to that first observed under natural infections in the private garden. The non-inoculated control plantlets (grown under the same conditions in a separate room) remained symptomless during the entire three weeks testing period. To our knowledge, this is the first report of Erysiphe corylacearum on hazelnut in Bulgaria. In October 2021, the same disease was also found in a hazelnut orchard (1.2 ha) located in the region of Pazardzhik (Central Southern part of the country). Globally, this report indicates the disease's expansion in the Black Sea region since its first observation in Turkey in 2013 (Sezer, A., et al. 2017; Heluta, V.P., et al. 2019; Meparishvili, G., et al. 2019; Rosati, M., et al. 2021) and elsewhere in Europe as well (Beenken, L., et al. 2020; Mezzalama, M., et al. 2021; Voglmayr, H., et al. 2021).

Prevalence of Intestinal Protozoa in Pigs of Northern Black Sea Region, Ukraine

Intestinal protozoan parasites threaten the health and welfare of pigs and impair the sustainability of pig farms, resulting in monetary losses. The present study aimed to determine the distribution of protozoa in large white pigs in the farms of Odesa, Mykolaiv, and Kherson regions in Ukraine. The parasitological surveys were conducted from March 2020 to March 2022 on three types of farms, including four large farms (&gt; 100 sows), six medium farms (25-100 sows), and eight small farms (&lt; 25 sows). A total of 3938 fecal samples from pigs of various age groups, namely 0-2-month piglets, 2-4-month piglets, pigs on fattening, and sows, were examined. Eimeria and isospores were determined using McMaster’s method in Raynaud’s modification, cryptosporidia by staining smears, blastocysts by the method of ethyl acetate-formalin concentration, and direct microscopy. The recorded protozoa were species Eimeria spp., Cystoisospora suis (syn. Isospora suis), Balantidium coli, Cryptosporidium spp., Blastocystis spp. These species of protozoa were observed in 31.1%, 49.0%, and 58.8% of pigs in large, medium-sized, and small farms, respectively. The findings indicated that Isospora suis and Eimeria spp. were most commonly present in piglets aged 0-2 months in large (29.7% and 23.0%, respectively), medium (32.3%, 29.4%), and small farms (30.0%, 13.5%). Balantidium coli was not registered in pigs from large farms, and in piglets 2-4 months old from small farms, the prevalence of infestation was 17.2%. Cryptosporidium spp. and Blastocystis spp. were mostly recorded in piglets 2-4 months old from small farms (16.2%, 7.1%). In large and medium-sized farms of the Northern Black Sea region, mono infestations were recorded the most (73.6%, 72.0%), while mixed two-component infestation dominated (52.5%) small farms. Intestinal protozoa should be considered in the differential diagnosis of intestinal disorders as major factors or concomitant intestinal pathogens.

Risk factors associated with Streptococcus suis cases on pig farms in Spain.

Streptococcus suis can cause meningitis, polyarthritis and acute death in piglets. However, the risk factors associated with S. suis infection remain incompletely understood. Therefore, a longitudinal study was carried out, in which six batches from two Spanish pig farms with S. suis problems were repeatedly examined to determine possible risk factors. A prospective case-control study was conducted, and potential risk factors were evaluated using mixed-effects logistic regression models. The explanatory variables included: (a) concomitant pathogens; (b) biomarkers associated with stress, inflammation and oxidative status; (c) farm environmental factors; and (d) parity and S. suis presence in sows. Three models were built to study the effect of these variables, including two to assess the risk factors involved in the subsequent development of disease. Risk factors for S. suis-associated disease included porcine reproductive and respiratory syndrome virus co-infection at weaning (odds ratio [OR] = 6.69), sow parity (OR = 0.71), haptoglobin level before weaning (OR = 1.01), relative humidity (OR = 1.11) and temperature (OR = 0.13). Laboratory diagnosis was done at the batch level, with individual diagnosis based on clinical signs only. This study confirms the multifactorial nature of S. suis-associated disease, with both environmental factors and factors related to the host involved in disease development. Controlling these factors may, therefore, help prevent the appearance of disease.

SARS-CoV-2 infection in children: A 24 months experience with focus on risk factors in a pediatric tertiary care hospital in Milan, Italy.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in children is characterized by a wide variety of expressions ranging from asymptomatic to, rarely, critical illness. The basis of this variability is not yet fully understood. The aim of this study was to identify clinical and genetic risk factors predisposing to disease susceptibility and progression in children. We enrolled 181 consecutive children aged less than 18 years hospitalized with or for SARS-CoV-2 infection during a period of 24 months. Demographic, clinical, laboratory, and microbiological data were collected. The development of coronavirus disease 2019 (COVID-19)-related complications and their specific therapies were assessed. In a subset of 79 children, a genetic analysis was carried out to evaluate the role of common COVID-19 genetic risk factors (chromosome 3 cluster; ABO-blood group system; FUT2, IFNAR2, OAS1/2/3, and DPP9 loci). The mean age of hospitalized children was 5.7 years, 30.9% of them being under 1 year of age. The majority of children (63%) were hospitalized for reasons different than COVID-19 and incidentally tested positive for SARS-CoV-2, while 37% were admitted for SARS-CoV-2 infection. Chronic underlying diseases were reported in 29.8% of children. The majority of children were asymptomatic or mildly symptomatic; only 12.7% developed a moderate to critical disease. A concomitant pathogen, mainly respiratory viruses, was isolated in 53.3%. Complications were reported in 7% of children admitted for other reasons and in 28.3% of those hospitalized for COVID-19. The respiratory system was most frequently involved, and the C-reactive protein was the laboratory test most related to the development of critical clinical complications. The main risk factors for complication development were prematurity [relative risk (RR) 3.8, 95% confidence interval (CI) 2.4-6.1], comorbidities (RR 4.5, 95% CI 3.3-5.6), and the presence of coinfections (RR 2.5, 95% CI 1.1-5.75). The OAS1/2/3 risk variant was the main genetic risk factor for pneumonia development [Odds ratio (OR) 3.28, 95% CI 1-10.7; p value 0.049]. Our study confirmed that COVID-19 is generally less severe in children, although complications can develop, especially in those with comorbidities (chronic diseases or prematurity) and coinfections. Variation at the OAS1/2/3 genes cluster is the main genetic risk factor predisposing to COVID-19 pneumonia in children.

Emerging Prevalence and Clinical Features of Elizabethkingia meningoseptica Infection in Southwest China: A 9-Year Retrospective Study and Systematic Review.

Elizabethkingia meningoseptica infections have gradually emerged as life-threatening nosocomial infections worldwide, accompanied by increasing incidence, multidrug resistance and poor outcomes. However, the epidemiology and clinical features of E. meningoseptica infection are still limited in mainland China. Patients with E. meningoseptica infections from 2011 to 2019 in southwestern China were retrospectively analyzed. The clinical features, infection patterns and outcomes were extracted from medical records and analyzed. A comprehensive systematic review was performed in accordance with PRISMA guidelines from conception to August 23, 2021. Ninety-two patients were ultimately included, with the prevalence rapidly rising from 0 in 2011 to 0.19 per 1000 inpatients in 2019. A total of 93.48% of E. meningoseptica isolates were multidrug resistant, including 100% resistance to carbapenem. Furthermore, 75% of E. meningoseptica infections were concomitant with other pathogens. The mortality of our cohort was 36.96%, with risk factors for mechanical ventilation (OR=9.51, P=0.004), male sex (OR=0.27, P=0.031) and more concomitant pathogens. After propensity score matching, central venous catheters, exposure to carbapenem and antifungal drugs, and underlying tumors were associated with E. meningoseptica infection. Sixteen articles were also summarized, with reported mortality rates ranging from 11.0% to 66.6%. Blood and respiratory tract were the common sources. Piperacillin/tazobactam, trimethoprim/sulfamethoxazole, fluoroquinolone and minocycline were the most sensitive antibiotics. Inappropriate antibiotic treatment was the most commonly reported risk factor for mortality. Nosocomial infection with E. meningoseptica has become an emerging problem with high mortality in southwestern China. Inappropriate antibiotic treatment and central venous catheters are risk factors for infection and death and should receive adequate attention.

Skin and Soft Tissue Infections due to Aeromonas spp.: An Emerging Pathogen

Introduction: Aeromonas spp., the emerging human pathogens, can cause various diseases like gastrointestinal infections, Skin and Soft-Tissue Infections (SSTIs), respiratory tract infections, urinary tract infection, hepatobiliary tract infection, blood stream infections etc. Aeromonas consists of important pathogenic species like Aeromonas hydrophila being the most common one followed by A.sobria, A.veroni, A.caviae and A.salmonicida. SSTIs due to Aeromonads are most often associated with preexisting ulcer, traumatic wound and exposure to water. Aim: The present study was carried out to analyse socioepidemiological factors, clinical features, risk factors and antibiotic resistance potential of Aeromonas spp., SSTIs. Materials and Methods: In this prospective study, all Gramnegative fermenting motile isolates which are positive for oxidase, H2 S production, indole reaction, lysine decarboxylase were further identified by Vitek 2 compact system (Biomerieux, France). The study period was 2 years. Results: A total of 39 patients with Aeromonas spp., SSTIs were identified during the period from 2020 to 2022. Majority of patients hailed from urban areas, were in middle age group and were farmers. A.hydrophila (n=24, 62%) was the predominant isolate. Majority of the infections were superinfection of wound (n=16, 41%) and chronic non healing ulcer (n=13, 33.3%). A total of 33.3% of infections were polymicrobial, common concomitant pathogens being, Pseudomonas aeruginosa and Methicillin Resistant Staphylococcus aureus (MRSA). Trauma and water exposure were main risk factors with co-morbidities like diabetes, hypertension and liver cirrhosis. A 20.5% of patients were immunocompromised. There was one case of Necrotising Fasciitis (NF) which resulted in patient’s death. Cotrimoxazole, 3rd and 4th generation cephalosporins. Aztreonam and Tigecycline were the most effective antibiotics while eight of the isolates were Multidrug Resistant (MDR). Thirty-three patients recovered completely and three patients died of complications. Conclusion: Aeromonas hydrophila must be regarded as an emerging pathogen of SSTIs mainly in patients with preexisting ulcers and can be MDR. Such infections have a good prognosis if prompt medical, surgical and supportive treatment is given.

Clinical and Microbiological Profile of Elizabethkingia meningoseptica Bacteraemia: A Cross-sectional Study from a Tertiary Care Centre in Northern India

Introduction: Elizabethkingia meningoseptica (E. meningoseptica) is an emerging pathogen that causes bloodstream infections, especially among immunocompromised or critically ill patients. Due to its multidrug resistance, limited antibiotic treatments are available. Therefore, correct identification with a proper susceptibility report is compulsory to reduce mortality and morbidity caused by this rare pathogen. Aim: To analyse the clinical features, underlying comorbidity, outcomes, and antibiotic resistance potential of E. meningoseptica causing bacteraemia. Materials and Methods: This cross-sectional study was conducted in Department of Microbiology, Rajshree Medical Research Institute (RMRI), Bareilly, Uttar Pradesh, India. The study spanned three years from August 2020 to July 2023. All patients with E. meningoseptica bacteraemia were identified from blood culture reports and included in the study. As it was a duration-based study, all consecutive patients identified with E. meningoseptica bacteraemia were enrolled. The total sample size was 43. Blood samples growing gram negative, non fermenting, non motile isolates that were positive for the oxidase reaction were further identified using the Vitek 2 compact system (Biomerieux, France). All relevant data regarding demographic and clinical characteristics, underlying diseases, and antibiotic treatments were collected from the hospital information system. Patient demographics were presented as mean ± standard deviation. Clinical characteristics and co-morbid conditions were presented as frequency and percentages. Results: The majority of patients were elderly males admitted to the Intensive Care Unit (ICU). The most common underlying co-morbidity was malignancy in 12 (27.9%), and pneumonia in 12 (48.8%) was the major diagnosis among these bacteraemic patients. A total of 10 (23.25%) infections were polymicrobial, with common concomitant pathogens being Pseudomonas aeruginosa and Methicillin-Resistant Staphylococcus aureus (MRSA). Co-trimoxazole, fluoroquinolones, and Piperacillin/ Tazobactam were the most effective antibiotics. Thirty-nine (90.7%) patients recovered completely, while four patients (9.3%) died of complications. Conclusion: Improper antimicrobial therapy increases resistance and mortality among patients with E. meningoseptica infections. It is imperative that clinicians remain vigilant about this rare pathogen and advise antimicrobial susceptibility testing for appropriate treatment, leading to favourable outcomes.

A Novel Approach to Vaccine Development: Concomitant Pathogen Inactivation and Host Immune Stimulation by Peroxynitrite.

The design of efficient vaccines for long-term protective immunity against pathogens represents an objective of utmost public health priority. In general, live attenuated vaccines are considered to be more effective than inactivated pathogens, yet potentially more reactogenic. Accordingly, inactivation protocols which do not compromise the pathogen’s ability to elicit protective immunity are highly beneficial. One of the sentinel mechanisms of the host innate immune system relies on the production of reactive nitrogen intermediates (RNI), which efficiently inactivate pathogens. Peroxynitrite (PN) is a prevalent RNI, assembled spontaneously upon the interaction of nitric oxide (NO) with superoxide. PN exerts its bactericidal effect by via the efficient oxidation of a broad range of biological molecules. Furthermore, the interaction of PN with proteins results in structural/chemical modifications, such as the oxidation of tryptophan, tyrosine, and cysteine residues, as well as the formation of carbonyl, dityrosine, and nitrotyrosine (NT). In addition to their role in innate immunity, these PN-mediated modifications of pathogen components may also augment the antigenicity of pathogen peptides and proteins, hence contributing to specific humoral responses. In the study reported here, a novel approach for vaccine development, consisting of pathogen inactivation by PN, combined with increased immunity of NT-containing peptides, is implemented as a proof-of-concept for vaccination against the intracellular pathogen Francisella tularensis (F. tularensis). In vivo experiments in a murine model of tularemia confirm that PN-inactivated F. tularensis formulations may rapidly stimulate innate and adaptive immune cells, conferring efficient protection against a lethal challenge, superior to that elicited by bacteria inactivated by the widely used formalin treatment.

Detection of Clostridioides difficile toxin B gene: benefits of identifying gastrointestinal pathogens by mPCR assay in the diagnosis of diarrhea in pediatric patients

BackgroundIn the pediatric population, severe Clostridioides difficile infection (CDI) sometimes occurs, but most cases are asymptomatic. The asymptomatic carriage rate in pediatric populations is reportedly higher than in the adult population. It is difficult to diagnose CDI, even if C. difficile is detected in children with diarrhea. This study aimed to evaluate the positivity rate of toxigenic C. difficile in the pediatric population with diarrhea.MethodsWe collected and retrospectively analyzed gastrointestinal pathogen multiplex PCR results of 960 patients to estimate the positivity rate of toxigenic C. difficile in pediatric populations aged between 0 and 18 years.ResultsThe overall rate of C. difficile toxin B positivity was 10.1% in the stool samples. The positivity rate peaked in 1-year-old infants (29/153, 19.0%) and continually decreased thereafter. The positivity rate we observed was lower than the rates described in the literature. Remarkably, no C. difficile was detected in neonates. Antibiotic usage was inversely related to the positivity rate, especially in infants < 2 years of age. The odds ratio of antibiotics was 0.44 (95% confidence interval (CI) 0.28–0.68; P < 0.001). The presence of concomitant gastrointestinal pathogens was not associated with toxigenic C. difficile positivity.ConclusionsEven though toxigenic C. difficile infection is neither an important nor a common cause of pediatric diarrhea, children can spread it to adults at risk of developing CDI. The pediatric population can act as hidden reservoirs for pathogenic strains in the community.

Evaluation of antibacterial activity of Citrus aurantium L. leaf extracts on bacteria isolated from blood of Hepatitis B positive individuals in Ondo State, Nigeria

Background: Concomitant bacterial pathogens associated with Hepatitis B infection could further increase the stress on the liver of infected individuals thereby complicating the infection. Objective: This necessitates the need to evaluate the antibacterial activity of Citrus aurantium L. leaf extracts on bacteria isolated from blood of Hepatitis B positive individuals in Ondo State, Nigeria. Method: The leaf extracts of Citrus aurantium (aqueous, ethanol and N-hexane) were assessed for possible antibacterial activities against some isolated bacteria from blood samples of HBV positive individuals were conducted using agar well diffusion technique. Results: Proteus mirabilis, S. typhi, S. aureus, Kl. pneumoniae, Ps. aeruginosa, E. coli, S. pneumoniae and Ch. Violaceum were isolated. The most frequently encountered bacterial species was S. aureus (52%). The ethanol leaf extract exerted the highest growth inhibitory activity on S. aureus, Kl. pneumoniae, Ps. auruginosa and E. coli. The aqueous leaf extract exerted the highest inhibitory on Ch. violaceum while the N- hexane extract exerted the highest growth inhibitory activity on P. mirabilis and Ps. aeruginosa. The extracts compared favorably well with conventional antibiotic (Ciprofloxacin) which is the positive control. The MIC of all the extracts ranged from 12.5 to 50.0 mg/ml while the MBC ranged from 25 to 100mg/ml. The analysis of the phytochemicals revealed the presence of tannins, flavonoids, terpenoids, steroids, cardiac glycoside and saponin in all the leaf extracts except for the absence of saponins in N-hexane extract. Conclusion: This study showed that these extracts could be exploited to treat infection caused by these bacterial pathogens

Mycobacterium bovis meningitis together with systemic brucellosis

M. bovis and Brucella spp. are zoonotic bacteria that can infect humans. These pathogens are usually seen in people who are primarily engaged in animal husbandry and consume infected animal products separately. Although our country is endemic for tuberculosis and brucellosis, it is rare to detect these two pathogens concomitantly. Thus, the case is instructive and unusual in terms of the coexistence of two concomitant zoonotic pathogens. Keywords: M. bovis; meningitis; brucellosis; concomitant.

A retrospective study to identify concomitant pathogens in Mycoplasma gallisepticum positive commercial turkeys and the development of a predictive model of Mycoplasma gallisepticum serologic status in California (2008–2019)

Mycoplasma gallisepticum ( MG ) is an economically significant pathogen of poultry which results in severe disease especially when complicated by other respiratory pathogens. The objectives of this study, were to establish preliminary baseline data on the respiratory pathogens in MG positive commercial turkey flocks in California and to identify key predictor variables of MG serologic status. The retrospective study analyzed a total of 54 flocks in which MG was confirmed in central California from 2008 to 2019 by California Animal Health and Food Safety laboratories ( CAHFS ). Of the 54 flocks that were confirmed positive by quantitative polymerase chain reaction ( qPCR ), 34 (63%) had positive MG ELISA titers and 20 (37%) were negative . Escherichia coli was the most common pathogen isolated in 13 (24.1%) flocks followed by Bordetella avium, Mycoplasma synoviae , and Ornithobacterium rhinotracheale in 10 (18.5%), 8 (14.8%), and 7 (13%), respectively. The mean age at which flocks were submitted for necropsy to the CAHFS laboratories and confirmed as MG qPCR positive was approximately 15 wk. To assess the main effects on MG serologic status, a stepwise logistic regression model was developed. Of the 6 independent variables examined (age of flock, season, farm size, company, number of concurrent pathogens and year), only age of flock (odds ratio = 1.7, P = 0.002) was determined to be a significant factor in the final model. This study provides preliminary baseline data on the concurrent infectious pathogens in qPCR MG positive commercial turkeys. It also identified potentially critical information as well as the age of detection, which may aid in the implementation of targeted control and prevention strategies.

Threats to soil and water resources in South Africa

South Africa has always been subject to an arid climate, receiving only slightly more than half of the world's average precipitation. This precarious situation is further exacerbated by very high potential evapotranspiration and an extremely rapid population growth. This paper aims to evaluate the threats to the soil and water resources of South Africa. These resources are vital in ensuring sustainable food production. Physically, wind and water erosion, structural decay, subsoil compaction and soil surface crusting are of great concern. Chemically, acidification, salinization, and pollution are the main concerns; with acidification mainly limited to the humid eastern parts and salinization to the arid western parts of South Africa. Biological degradation is mainly driven by organic matter decline, reducing the already low soil organic carbon content of South African soils. The extent of organism decline and the concomitant pathogen increase is not that well-known. Water resources in South Africa are very limited and of variable certainty. Water use efficiency, especially in agriculture and forestry, should receive urgent attention, since these are the main consumers of this valuable resource. Sedimentation, salinization, and pollution constitute the main impacts on water quality. Water pollution arises mainly from point sources such as municipal effluent, with smaller impacts from industry and feedlots. Given the varied nature of institutions and role-players involved in soil and water degradation, it is vital that one or more national institutions take responsibility to monitor and at least attempt to rectify and/or manage the degradation of South Africa's soil and water resources. In this regard substantial financial support from the private sector would also be imperative.

Infectious Coryza: Persistence, Genotyping, and Vaccine Testing.

The reemergence of infectious coryza (IC) caused by Avibacterium paragallinarum (AP) as an acute and occasionally chronic respiratory disease in domestic poultry has caused severe losses in several U.S. states. The disease is also associated with decreased egg production in layers and increased condemnations from air sac infections in broilers. A series of applied experiments were performed to elucidate the persistence of AP in infected broiler flocks, to genotype AP strains isolated from field cases, and to evaluate commercial and autogenous vaccine protection in commercial and specific-pathogen-free (SPF) chickens. Experimental evaluation of environmental persistence suggests that AP did not persist more than 12 hr in a hypothetically contaminated environment. Additionally, other detected potential pathogens such as Gallibacterium anatis and infectious bronchitis virus caused mild respiratory signs in the exposed birds. The HMTp210 and HagA genes of four IC field strains were sequenced and compared with published sequences of HMTp210 and HagA. The HMTp210 phylogeny showed a marginally imperfect clustering of the sequences in genogroups A, B, and C. Although not definitive, this phylogeny provided evidence that the four field strains aligned with previously characterized serovar C strains. Moreover, the base pair homology of the four strains was 100% identical to serovar C reference strains (H-18 and Modesto). HagA phylogeny was unclear, but interestingly, the IC field strains were 100% homologous to C-1 strains reported from Mexico and Ecuador. Finally, vaccine protection studies in commercial hens indicate that clinical signs are induced by a combination of IC and other concomitant pathogens infecting commercial birds. Additionally, vaccine protection experiments performed in SPF hens indicated that protection provided by the two commercial vaccines tested provided a reduction in clinical signs and bacterial shedding after two applications.

Mass Reproduction of Polygraphus proximus Blandford in Fir Forests of Siberia Infected with Root and Stem Pathogens: Monitoring, Patterns, and Biological Control

Conifer decline (Abies sibirica Ledeb. stands) as a result of complex biotic effects on the territory of Krasnoyarsk krai by 2018 reached an area of 541 400 ha; the potential area of further death of A. sibirica is up to 10 million ha. The main reason is the phytopathogenic fungi Armillaria mellea s.l. and Heterobasidion annosum s.l. combined with bark beetle Polygraphus proximus. Trees affected by root pathogens are centers of forest dieback, from which pathological outbreaks spread, including the effects of P. proximus and its phytopathogenic mycoassociates. Neonectria fuckeliana (C. Booth) Castl & Rossman is among the concomitant pathogens in the scale of the lesion, which causes a resin flow that is similar to the effects of P. proximus attack. The phytopathogenicity of pure cultures of the dominant root pathogens of Armillaria borealis Marxm. & Korhonen and Heterobasidion annosum (Fr.) Bref., as well as the stem pathogen of N. fuckeliana, has been confirmed by a series of experiments in vitro. Promising natural agents for the regulation of P. proximus abundance are highly virulent aboriginal strains of Beauveria bassiana (Bals.–Criv.) Vuill., resulting in maximum insect death (up to 100%) for 7–11 days and retaining activity in the temperature range of 16–24 ± 1°C.

English

INTRODUCTION : Infections caused by the yeasts of the genus candida are common in clinical practice. They may involve the mucous membranes and / or skin or spread internally to produce systemic infections. Superficial infections of the mucous membranes and skin are numerically most important but more serious involvement of the internal organs as in septicemia, endocarditis, meningitis, can also occur. Candida albicans is an oval yeast 2-6 x 3-9 μm in size, which can produce budding cells, pseudohyphae and true hyphae. The ability to simultaneously display several morphological forms is known as polymorphism. Although hyphae are likely to be produced during the process of tissue invasion, yeasts without hyphae may also occur in invasive disease, particularly in infections caused by non-albicans candida species. AIM AND OBJECTIVE OF THE STUDY : The term immunocompromised host is used to define a patient with impaired host defences who is at the risk of developing an opportunistic infection. This includes patients with immunodeficiency because of the disease perse such as patients with ‘Acquired Immune Deficiency Syndrome’ (AIDS) or induced iatrogenically as a result of chemotherapy. Susceptibility to infection is increased when normal host defence mechanisms are compromised by underlying disease states, therapeutic interventions or iatrogenic manipulations. Frequently all the three factors play a role in creating an immunocompromised state, in which infection is likely. Candida species are the most common cause of systemic fungal infections in the immunocompromised patients (Hawkins, 1984). This study has been designed, 1. To isolate, culture and subculture thereby identify the subspecies of candida from the mucosal lesions of immunocompromised individuals. 2. To study the age and sex distribution of immunosuppressed patients suffering from candidiasis. 3. To study the morphological pattern of lesions in the background of immunosuppression. 4. To identify the subspecies of candida causing various types of lesions in immunosuppressed patients. 5. To study the dose and duration of the immunosuppressive therapy that predisposed to candidasis. CONCLUSIONS : * Candidiasis is the commonest mycosis in patients on systemic immunosuppressive therapy and immunosuppressive status like HIV infection. * Majority of the affected victims of candidiasis, were in the age group between 31-50 years. Incidence of candidiasis was found to be more in male patients than female patients. (Males → 62%). (Females → 38%). However the age and sex distribution is also related to the patients screened. * Acute pseudomembranous glossitis was the commonest morphological type of the lesion encountered in this study (35%), to be followed by, chronic erythematous candidiasis (22%), Angular cheilitis (21%), acute erythematous glossitis (19%), balanoposthitis (2%) & Median rhomboid glossitis (1%). * Among the various immunosuppressive drugs taken into account for this study, Tab.Prednisolone was the commonest drug predisposing to candidiasis (28%) followed by Inj. Dexamethasone (22%). Thus systemic steroids accounted for 50% of drugs predisposing to candidosis, remaining 50% being contributed by cytotoxic drugs like methotrexate, cyclophosphamide, azathioprine etc; * Of all the various bullous dermatoses screened, pemphigus vulgaris was the commonest bullous disorder predisposing to candidosis (40%) followed by bullous pemphigoid (16.6%), Pemphigus foliaceus (8.3%), Dermatitis Herpetiformis (1.6%) and Pemphigus vegetans (5%). * Candida albicans was the commonest species isolated (52%). Other species isolated include, Candida tropicalis (22%), Candida glabrata (21%), Candida krusei (3%) and Candida dubliniensis (2%). * Patients with O+ve Blood group are considered to have high carriage of candidia species. * Even in HIV infected individuals, candida albicans was the commonest species isolated, in our study; candida dubliniensis is said to be exclusively common in the oral lesions of HIV patients, which however accounted only for (2%) in our study. Probably the sample size had still been larger. * The minimum time duration of systemic immunosuppressive therapy required for predisposition to oral candidosis was found to be 10 (Ten) days in our study in Non-HIV infected individuals, which was found to be still shorter in known cases of HIV infection (around 1 week); probably due to CD4 cell count depletion, and other associated opportunistic infections. * Inspite of heroic measures to avoid contaminants, and adhering to very strict aseptic protocols, it was found in our study that the maximum keeping time of primary candida culture in SDA with chloramphenicol and subcultures in Himedia CHROMagar was just 72 hours, after which saprophytic bacteria and various moulds and concomitant pathogens spoil the culture media.