Burden of Serious Bacterial Infections and Multidrug-Resistant Organisms in an Adult Population of Nepal: A Comparative Analysis of Minimally Invasive Tissue Sampling Informed Mortality Surveillance of Community and Hospital Deaths

Multiplex detection of bacterial pathogens by PCR/SERS assay

Bacterial infections are a leading cause of death globally. The detection of DNA sequences correlated to the causative pathogen has become a vital tool in medical diagnostics. In practice, PCR-based assays for the simultaneous detection of multiple pathogens currently rely on probe-based quantitative strategies that require expensive equipment but have limited sensitivity or multiplexing capabilities. Hence, novel approaches to address the limitations of the current gold standard methods are still in high demand. In this study, we propose a simple multiplex PCR/SERS assay for the simultaneous detection of four bacterial pathogens, namely P. aeruginosa, S. aureus, S. epidermidis, and M. smegmatis. Wherein, specific primers for amplifying each target gDNA were applied, followed by applying SERS nanotags functionalized with complementary DNA probes and Raman reporters for specific identification of the target bacterial pathogens. The PCR/SERS assay showed high specificity and sensitivity for genotyping bacterial pathogen gDNA, whereby as few as 100 copies of the target gDNA could be detected. With high sensitivity and the convenience of standard PCR amplification, the proposed assay shows great potential for the sensitive detection of multiple pathogen infections to aid clinical decision-making.

MAIT cells in bacterial infectious diseases: heroes, villains, or both?

Due to the aggravation of bacterial drug resistance and the lag in the development of new antibiotics, it is crucial to develop novel therapeutic regimens for bacterial infectious diseases. Currently, immunotherapy is a promising regimen for the treatment of infectious diseases. Mucosal-associated invariant T (MAIT) cells, a subpopulation of innate-like T cells, are abundant in humans and can mount a rapid immune response to pathogens, thus becoming a potential target of immunotherapy for infectious diseases. At the site of infection, activated MAIT cells perform complex biological functions by secreting a variety of cytokines and cytotoxic substances. Many studies have shown that MAIT cells have immunoprotective effects because they can bridge innate and adaptive immune responses, leading to bacterial clearance, tissue repair, and homeostasis maintenance. MAIT cells also participate in cytokine storm generation, tissue fibrosis, and cancer progression, indicating that they play a role in immunopathology. In this article, we review recent studies of MAIT cells, discuss their dual roles in bacterial infectious diseases and provide some promising MAIT cell-targeting strategies for the treatment of bacterial infectious diseases.

Bioprospecting of unexplored halophilic actinobacteria against human infectious pathogens

Human pathogenic diseases received much attention recently due to their uncontrolled spread of antimicrobial resistance (AMR) which causes several threads every year. Effective alternate antimicrobials are urgently required to combat those disease causing infectious microbes. Halophilic actinobacteria revealed huge potentials and unexplored cultivable/non-cultivable actinobacterial species producing enormous antimicrobials have been proved in several genomics approaches. Potential gene clusters, PKS and NRPKS from Nocardia, Salinospora, Rhodococcus, and Streptomyces have wide range coding genes of secondary metabolites. Biosynthetic pathways identification via various approaches like genome mining, In silico, OSMAC (one strain many compound) analysis provides better identification of knowing the active metabolites using several databases like AMP, APD and CRAMPR, etc. Genome constellations of actinobacteria particularly the prediction of BGCs (Biosynthetic Gene Clusters) to mine the bioactive molecules such as pigments, biosurfactants and few enzymes have been reported for antimicrobial activity. Saltpan, saltlake, lagoon and haloalkali environment exploring potential actinobacterial strains Micromonospora, Kocuria, Pseudonocardia, and Nocardiopsis revealed several acids and ester derivatives with antimicrobial potential. Marine sediments and marine macro organisms have been found as significant population holders of potential actinobacterial strains. Deadly infectious diseases (IDs) including tuberculosis, ventilator-associated pneumonia and Candidiasis, have been targeted by halo-actinobacterial metabolites with promising results. Methicillin resistant Staphylococus aureus and virus like Encephalitic alphaviruses were potentially targeted by halophilic actinobacterial metabolites by the compound Homoseongomycin from sponge associated antinobacterium. In this review, we discuss the potential antimicrobial properties of various biomolecules extracted from the unexplored halophilic actinobacterial strains specifically against human infectious pathogens along with prospective genomic constellations.

Unveiling the volatile compounds and antibacterial mechanisms of action of Cupressus sempervirens L., against Bacillus subtilis and Pseudomonas aeruginosa

Cupressus sempervirens is a known traditional plant used to manage various ailments, including cancer, inflammatory and infectious diseases. In this investigation, we aimed to explore the chemical profile of Cupressus sempervirens essential oil (CSEO) as well as their antibacterial mode of action. The volatile components were characterized using gas chromatography coupled to a mass spectrometer (GC-MS). The results revealed remarkable antibacterial properties of EO derived from C. sempervirens. GC-MS analysis indicated that C. sempervirens EO characterized by δ-3-carene (47.72%), D-limonene (5.44%), β-pinene (4.36%), β-myrcene (4.02%). The oil exhibited significant inhibitory effects against a range of bacteria, including Staphylococcus aureus ATCC 29213, Bacillus subtilis ATCC 13048, Bacillus cereus (Clinical isolate), Pseudomonas aeruginosa ATCC 27853, and Escherichia coli ATCC 25922. These inhibitory effects surpassed those of conventional antibiotics. Furthermore, the EO demonstrated low minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs), indicating its bactericidal nature (MBC/MIC < 4.0). Time-kill kinetics analysis showed that CSEO was particularly effective at 2 × MIC doses, rapidly reduced viable count of B. subtilis and P. aeruginosa within 8 h. This suggests that the oil acts quickly and efficiently. The cell membrane permeability test further demonstrated the impact of CSEO on the relative conductivity of B. subtilis and P. aeruginosa, both at 2 × MIC concentrations. These observations suggest that EO disrupts the bacterial membrane, thereby influencing their growth and viability. Additionally, the cell membrane integrity test indicated that the addition of CSEO to bacterial cultures resulted in the significant release of proteins from the bacterial cells. This suggests that EO affects the structural integrity of the bacterial cells. Furthermore, the anti-biofilm assay confirmed the efficacy of CSEO as a potent anti-biofilm agent. It demonstrated the oil's ability to inhibit quorum sensing, a crucial mechanism for biofilm formation, and its competitive performance compared to the tested antibiotics.

Effect of antibiotic medicines availability on adherence to standard treatment guidelines among hospitalized adult patients in southern Malawi

BACKGROUND

Antibiotic resistance is a global public health problem. High and inappropriate use of antibiotic therapy exacerbate the risk of antibiotic resistance. We assessed the effect of availability of antibiotic medicines on adherence to standard treatment guidelines among hospitalized adult patients in Southern Malawi.

METHODS

A cross-sectional study was done to assess the availability of 16 antibiotics among the first-line recommended treatments for common bacterial infections in Malawi. Data for up to six-month duration was extracted from stock card records in Machinga and Nsanje District Hospitals and Zomba Central Hospital. This was complemented by a retrospective review of 322 patient management files from medical wards to assess adherence to the Malawi Standard Treatment Guidelines (MSTG). Investigators abstracted data such as patient demographics, diagnoses, and prescribed therapy using a data collection form that resulted in analyzing 304 patient files. Data was entered into Microsoft excel and analyzed using STATA 14.1. Point availability, stock-out duration and adherence to treatment guidelines were presented in terms of frequencies and percentages. Chi-square test or Fisher's exact test was applied to assess the association between variables and adherence to treatment guidelines.

RESULTS

Point availability of antibiotics was 81.5%, 87.7%, and 42.8% for Zomba Central, Machinga and Nsanje District Hospitals respectively. Over a period of six months, 12.5% of antibiotic medicines were stocked out for at least one day at Zomba (Median stock out days = 0, (IQR 0-0 days), while 64.3% were stocked out at Machinga (Median stock out days = 21, IQR 0-31 days) and 85.7% were stocked out at Nsanje District Hospital (Median stock out days = 66.5, IQR 18-113 days). Overall, adherence to MSTG was 79.6%, (95% CI, 73.3-84.9%). By facilities, adherence to guidelines at Zomba Central Hospital was 95.9% (95% CI, 89.7-98.9%) while at Nsanje and Machinga District Hospitals was 73.2% (95% CI, 59.7-84.2%) and 54.2% (95% CI, 39.2-68.6%) respectively. Adherence to treatment guidelines was associated with health facility, presence of laboratory test results, antibiotic spectrum, and WHO-AWaRe category of the medicine, p<0.005. Adherence was lower for antibiotics that were stocked out than antibiotics that were not stocked out during the study period (63.8%, 95% CI 48.5-77.3% vs 84.4%, 95% CI 77.7-89.8%), p< 0.002.

CONCLUSION

We found unstable availability of antibiotic medicines in hospitals which might contribute to the sub-optimal adherence to standard treatment guidelines. This is a setback to efforts aimed at curbing antibiotic resistance in Malawi.

Determination of causes of adult deaths using minimally invasive tissue sampling in Gandaki province of Nepal: a multicenter hospital-based study

BACKGROUND

Minimally Invasive Tissue Sampling (MITS) has been successfully used to establish the cause of death in low- and middle-income countries, mostly in stillbirths and neonates. The objective of this study was to determine the causes of death among adults using MITS in the Gandaki province of Nepal and to find out the contribution of MITS to identify the causes of death.

METHODS

A multicentric hospital-based pilot study was conducted to enroll 100 cases of adult deaths. The specimens of cerebrospinal fluid, blood, brain, lungs, and liver tissue were collected utilizing MITS. These specimens underwent standard histopathological, serological, and microbiological analyses. The findings from MITS, and if available, clinical records and forensic autopsy findings were compiled and the cause of death panel identified the causes of death. The final cause of death allocated to each case was based on the WHO International Medical Certificate of Death.

RESULTS

Among a total of 100 cases enrolled during the study period, infectious cause attributed to the immediate cause of death in 77 (77%), cardiovascular in 10 (10%), neurological in 8 (8%), malignancy in two (2%), and gastrointestinal and hepatobiliary cause in one (1%) case. The mean age of the cases was 50.8 ± 15.9 years and 76 (76%) were males. MITS established the cause of death in the causal chain of events in 81(81%) cases and identified the cause of death significantly more with infectious than non-infectious causes (p < 0.001).

CONCLUSIONS

MITS was useful in establishing the cause of death in the majority of adult deaths and the most common cause was infectious disease. Our findings suggest that MITS can be a valuable and alternative tool for mortality surveillance in low-resource settings, where complete diagnostic autopsies are less accepted or less prioritized.

Isoniazid Mono-Resistant Tuberculosis Presenting as Empyema Thoracis With Citrobacter koseri and Morganella morganii Infections: The World's First Reported Case of Its Type

Drug resistance is very common in developing countries. Isolated cases of concomitant infection with Mycobacterium tuberculosis, Citrobacter koseri, and Morganella morganii are rare. Furthermore, there is no report available in the literature of concurrent infection of Citrobacter koseri and Morganella morganii in an isoniazid mono-resistant tuberculosis patient. In this case, we present a concomitant infection with drug-resistant strains of Mycobacterium tuberculosis, Citrobacter koseri, and Morganella morganii in a 40-year-old Indian male who presented with fever, dry cough, and chest pain. He was initiated on an isoniazid mono regimen and a broad-spectrum antibiotic, following the national guidelines.

Bridge-DNA synthesis triggered by an allosteric aptamer for the colorimetric detection of pathogenic bacteria

Rapid and sensitive quantification of pathogenic bacteria is highly desired for environmental health supervision and food safety control. Yet, the amplification and detection of bacteria with a concentration lower than 10² cfu mL^-1 remains a great challenge. Here, we combined an allosteric aptamer (AAP) with a gold nanoparticle (AuNP) for assembling a bridge-DNA synthesis system (named as AuNP-BDS) to amplify the bacterial signals. The AAP and its paired primer (PP) were covalently linked to two different AuNPs, respectively: one named as AAP-AuNP and the other PP-AuNP. Upon recognition of the antigen from the pathogenic bacteria, AAP alters its conformation to initiate DNA synthesis on the AuNP surface. The DNA products from AAP-AuNP and PP-AuNP form bridges to each other through base pairing, resulting in the aggregation and colorimetric response of the AuNPs. By using E. coli O157:H7 as an example, the AuNP-BDS could quantify pathogenic bacteria in water with a concentration as low as 10 cfu mL^-1 within 60 min and without any enrichment. The colorimetric response values of AuNP-BDS were found to be linearly related to the bacterial concentrations in the range of 10 to 10³ cfu mL^-1. Good practicability of the AuNP-BDS in quantifying E. coli O157:H7 from tap water, juices, and milks was demonstrated. The AuNP-BDS could be exploited to facilitate the rapid and sensitive quantification of pathogenic bacteria for food safety control.

Prevalence of Antibiotic Use and Disposal at Household Level in Informal Settlements of Kisumu, Kenya

The use and abuse of antibiotics are directly related to the development of drug resistance, a global public health problem. Whereas the majority of research focus is on the use and misuse of antibiotics in drug resistance development, little is known about improper disposal, as a source of contamination in the environment that includes groundwater, especially in informal settlements. This study sought to determine antibiotic use and disposal in informal settlements in Kisumu, Kenya. A random cross-sectional sample of 447 households in selected informal settlements of Kisumu, Kenya was studied. A structured questionnaire was issued to persons heading households. The prevalence of antibiotic use was 43% (n = 193). Among these people, 74% (n = 144) had consulted a health worker in a healthcare facility for a prescription. Respondents did not always complete doses but kept the remainder for the next time they would become ill (54%). About 32% disposed of the remainder of the antibiotics in pit latrines and compost pits (10%) while 4% disposed through burning. Antibiotic use was fairly high despite a low level of awareness of the health effects of consuming water contaminated with antibiotics (35%) (n = 156); p = 0.03. Misuse and inappropriate disposal of antibiotics as identified may lead to a higher risk of antibiotic resistance, increasing the disease burden in the informal settlements.

Social determinants of health and the double burden of disease in Nepal: a secondary analysis

Background

As the global burden of disease evolves, lower-resource countries like Nepal face a double burden of non-communicable and infectious disease. Rapid adaptation is required for Nepal’s health system to provide life-long, person-centred care while simultaneously improving quality of infectious disease services. Social determinants of health be key in addressing health disparities and could direct policy decisions to promote health and manage the disease burden. Thus, we explore the association of social determinants with the double burden of disease in Nepal.

Methods

This is a retrospective, ecological, cross-sectional analysis of infectious and non-communicable disease outcome data (2017 to 2019) and data on social determinants of health (2011 to 2013) for 753 municipalities in Nepal. Multinomial logistic regression was conducted to evaluate the associations between social determinants and disease burden.

Results

The ‘high-burden’ combined double burden (non-communicable and infectious disease) outcome was associated with more accessible municipalities, (adjOR3.94[95%CI2.94–5.28]), municipalities with higher proportions of vaccine coverage (adjOR12.49[95%CI3.05–51.09]) and malnutrition (adjOR9.19E103[95%CI19.68E42-8.72E164]), lower average number of people per household (adjOR0.32[95%CI0.22–0.47]) and lower indigenous population (adjOR0.20[95%CI0.06–0.65]) compared to the ‘low-burden’ category on multivariable analysis. ‘High-burden’ of non-communicable disease was associated with more accessible municipalities (adjOR1.93[95%CI1.45–2.57]), higher female proportion within the municipality (adjOR1.69E8[95%CI3227.74–8.82E12]), nutritional deficiency (adjOR1.39E17[95%CI11799.83–1.64E30]) and malnutrition (adjOR2.17E131[95%CI4.41E79-1.07E183]) and lower proportions of population under five years (adjOR1.05E-10[95%CI9.95E-18–0.001]), indigenous population (adjOR0.32[95%CI0.11–0.91]), average people per household (adjOR0.44[95%CI0.26–0.73]) and households with no piped water (adjOR0.21[95%CI0.09–0.49]), compared to the ‘low-burden’ category on adjusted analysis. ‘High burden’ of infectious disease was also associated with more accessible municipalities (adjOR4.29[95%CI3.05–6.05]), higher proportions of population under five years (adjOR3.78E9[95%CI9418.25–1.51E15]), vaccine coverage (adjOR25.42[95%CI7.85–82.29]) and malnutrition (adjOR4.29E41[95%CI12408.29–1.48E79]) and lower proportions of households using firewood as fuel (adjOR0.39[95%CI0.20–0.79]) (‘moderate-burden’ category only) compared to ‘low-burden’.

Conclusions

While this study produced imprecise estimates and cannot be interpreted for individual risk, more accessible municipalities were consistently associated with higher disease burden than remote areas. Female sex, lower average number per household, non-indigenous population and poor nutrition were also associated with higher burden of disease and offer targets to direct interventions to reduce the burden of infectious and non-communicable disease and manage the double burden of disease in Nepal.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-022-13905-3.