Assessment of antimicrobial resistance laboratory-based surveillance capacity of hospitals in Zambia: findings and implications for system strengthening.

BACKGROUND: A well-established antimicrobial resistance (AMR) laboratory-based surveillance (LBS) is of utmost importance in a country like Zambia which bears a significant proportion of the world's communicable disease burden. This study assessed the capacity of laboratories in selected hospitals to conduct AMR surveillance in Zambia. METHODS: This cross-sectional exploratory study was conducted among eight purposively selected hospitals in Zambia between August 2023 and December 2023. Data were collected using the self-scoring Laboratory Assessment of Antibiotic Resistance Testing Capacity (LAARC) tool. FINDINGS: Of the assessed facilities, none had full capacity to conduct AMR surveillance with varying capacities ranging from moderate (63% (5/8)) to low (38% (3/8)). Some of the barriers of AMR-LBS were the lack of an electronic laboratory information system (63% (5/8)) and the lack of locally generated antibiograms (75% (6/8)). Quality control for antimicrobial susceptibility testing (AST), pathogen identification and media preparation had the lowest overall score among all of the facilities with a score of 14%, 20% and 44%, respectively. The highest overall scores were in specimen processing (79%), data management (78%), specimen collection, transport and management (71%), and safety (70%). Most facilities had standard operating procedures in place but lacked specimen-specific standard operating procedures. CONCLUSION: The absence of laboratories with full capacity to conduct AMR surveillance hinders efforts to combat AMR and further complicates the treatment outcomes of infectious diseases. Establishing and strengthening LBS systems are essential in quantifying the burden of AMR and supporting the development of local antibiograms and treatment guidelines.

Aetiology and prognosis of community-acquired pneumonia at the Adult University Teaching Hospital in Zambia.

BACKGROUND: Community-acquired pneumonia (CAP) is a frequent cause of death worldwide, and in sub-Saharan Africa particularly. Human immunodeficiency virus infection (HIV) and tuberculosis (TB) influence pathogen distribution in patients with CAP. Previous studies in sub-Saharan Africa have shown different frequencies of respiratory pathogens and antibiotic susceptibility compared to studies outside Africa. This study aimed to investigate the aetiology, presentation, and treatment outcomes of community-acquired pneumonia in adults at the University Teaching Hospital in Lusaka, Zambia. MATERIALS AND METHODS: Three-hundred-and-twenty-seven patients were enrolled at the University Teaching Hospital in Lusaka between March 2018 and December 2018. Clinical characteristics and laboratory data were collected. Sputum samples were tested by microscopy, other TB diagnostics, and bacterial cultures. RESULTS: The commonest presenting complaint was cough (96%), followed by chest pain (60.6%), fever (59.3%), and breathlessness (58.4%). The most common finding on auscultation of the lungs was chest crackles (51.7%). Seventy percent of the study participants had complaints lasting at least a week before enrolment. The prevalence of HIV was 71%. Sputum samples were tested for 286 patients. The diagnostic yield was 59%. The most common isolate was Mycobacterium tuberculosis (20%), followed by Candida species (18%), Klebsiella pneumoniae (12%), and Pseudomonas aeruginosa (7%). Streptococcus pneumoniae was isolated in only four patients. There were no statistically significant differences between the rates of specific pathogens identified in HIV-infected patients compared with the HIV-uninfected. Thirty-day mortality was 30%. Patients with TB had higher 30-day mortality than patients without TB (p = 0.047). CONCLUSION: Mycobacterium tuberculosis was the most common cause of CAP isolated in adults at the University Teaching Hospital in Lusaka, Zambia. Gram-negative organisms were frequently isolated. A high mortality rate was observed, as 30% of the followed-up study population had died after 30 days.

Potential of di-aldehyde cellulose for sustained release of oxytetracycline: A pharmacokinetic study.

This study focused on the in-vivo sustained release of oxytetracycline (OTC) loaded on di-aldehyde cellulose (DAC). The periodate oxidation method was used for the synthesis of DAC. The prepared DAC-OTC material was characterized by different techniques such as Scanning electron microscopy (SEM), Fourier transforms infrared spectroscopy (FT-IR), X-ray diffraction (XRD), Transmission electron microscopy (TEM) and particle size analyzer. The pharmacokinetic studies were performed on DAC-OTC composite system and commercial tablet (COTA). The results of pharmacokinetic studies demonstrated that DAC-OTC exhibited higher area under the curve (AUC) (482.8 µghmL-1) as compared to COTA (90.72 µghmL-1). DAC-OTC composite system has double compartment pattern with improvement in mean residing time (MRT) and area under moment curve (AUMC0-∞) than the commercial tablet (2.8 and 15.13 folds higher, respectively). Swelling index of DAC-OTC at different pH and pKa of OTC release imply that controlled in-vivo release in DAC-OTC composite system could be due to the simultaneous occurrence of the covalent and hydrogen bond between OTC and di-aldehyde cellulose. These results indicate that di-aldehyde cellulose may improve the in-vivo bioavailability of OTC.

Exosomes in immunoregulation of chronic lung diseases.

Exosomes are nano-sized, membrane-bound vesicles released from cells that transport cargo including DNA, RNA, and proteins, between cells as a form of intercellular communication. In addition to their role in intercellular communication, exosomes are beginning to be appreciated as agents of immunoregulation that can modulate antigen presentation, immune activation, suppression, and surveillance. This article summarizes how these multifaceted functions of exosomes may promote development and/or progression of chronic inflammatory lung diseases including asthma, chronic obstructive pulmonary disease, and pulmonary fibrosis. The potential of exosomes as a novel therapeutic is also discussed.

Distribution of Class II integrons and their contribution to antibiotic resistance within Enterobacteriaceae family in India.

BACKGROUND: Integrons are the main contributors to the development of multidrug resistance (MDR) among Gram-negative bacilli. There is a lack of knowledge about the molecular relation between gene cassettes and antibiotic resistance in India. OBJECTIVE: In this study, we have investigated the occurrence of Class II integron and their cassette array among Enterobacteriaceae. MATERIALS AND METHODS: A total of 268 MDR non-duplicate strains of Enterobacteriaceae were collected from Silchar Medical College and Hospital, Silchar, Assam, India, during June 2012 to May 2013. Polymerase chain reaction was performed for detection of the integrase genes and gene cassettes within the Class II integron which were further analysed by sequencing. RESULTS: Class II integron was observed in 47 isolates. Four different gene cassette arrangements were detected: dfrA1-sat2-aadA1; dfrA1-sat2-aadA1-orfX-ybeA-ybfA-ybfB-ybgA; dfrA12-sat2-aadA1; and dfrA1-linF-aadA1. The most prevalent cassette combination was dfrA1-sat2-aadA1. This study has also identified a set of gene cassette associated with linF gene instead of sat2 gene. CONCLUSION: Further investigation is required to determine the current situation and important reservoir of Class II integron for the transmission of drug resistance among Enterobacteriaceae and their contribution to antimicrobial resistance in hospital environment .

Contribution of efflux pumps in fluroquinolone resistance in multi-drug resistant nosocomial isolates of Pseudomanas aeruginosa from a tertiary referral hospital in north east India.

BACKGROUND: Pseudomonas aeruginosa is one of the leading opportunistic pathogen and its ability to acquire resistance against series of antimicrobial agents confine treatment option for nosocomial infections. Increasing resistance to fluroquinolone (FQ) agents has further worsened the scenario. The major mechanism of resistance to FQs includes mutation in FQs target genes in bacteria (DNA gyrase and/or topoisomerases) and overexpression of antibiotic efflux pumps. OBJECTIVE: We have investigated the role of efflux pump mediated FQ resistance in nosocomial isolates of P. aeruginosa from a tertiary referral hospital in north eastern part of India. MATERIALS AND METHODS: A total of 234 non-duplicate, consecutive clinical isolates of P. aeruginosa were obtained from a tertiary referral hospital of north-east India. An efflux pump inhibitor (EPI), carbonyl cyanide m-chlorophenylhydrazone (CCCP) based method was used for determination of efflux pump activity and multiplex polymerase chain reaction (PCR) was performed for molecular characterisation of efflux pump. Minimum inhibitory concentration (MIC) reduction assay was also performed for all the isolates. RESULTS AND CONCLUSION: A total number of 56 (23%) have shown efflux mediated FQ resistance. MexAB-OprM efflux system was predominant type. This is the first report of efflux pump mediated FQ resistance from this part of the world and the continued emergence of these mutants with such high MIC range from this part of the world demands serious awareness, diagnostic intervention, and proper therapeutic option.

Synthesis of combretastatin A4 analogues on steroidal framework and their anti-breast cancer activity.

Combretastatin A4 analogues were synthesized on steroidal framework from gallic acid with a possibility of anti-breast cancer agents. Twenty two analogues were synthesized and evaluated for cytotoxicity against human breast cancer cell lines (MCF-7 & MDA-MB 231). The best analogue 22 showed potent antitubulin effect. Docking experiments also supported strong binding affinity of 22 to microtubule polymerase. In cell cycle analysis, 22 induced apoptosis in MCF-7 cells significantly. It was found to be non-toxic up to 300 mg/kg dose in Swiss albino mice in acute oral toxicity. This article is part of a Special Issue entitled "Synthesis and biological testing of steroid derivatives as inhibitors".

Metformin ameliorates IL-6-induced hepatic insulin resistance via induction of orphan nuclear receptor small heterodimer partner (SHP) in mouse models.

AIMS/HYPOTHESIS: IL-6 is a proinflammatory cytokine associated with the pathogenesis of hepatic diseases. Metformin is an anti-diabetic drug used for the treatment of type 2 diabetes, and orphan nuclear receptor small heterodimer partner (SHP, also known as NR0B2), a transcriptional co-repressor, plays an important role in maintaining metabolic homeostasis. Here, we demonstrate that metformin-mediated activation of AMP-activated protein kinase (AMPK) increases SHP protein production and regulates IL-6-induced hepatic insulin resistance. METHODS: We investigated metformin-mediated SHP production improved insulin resistance through the regulation of an IL-6-dependent pathway (involving signal transducer and activator of transcription 3 [STAT3] and suppressor of cytokine signalling 3 [SOCS3]) in both Shp knockdown and Shp null mice. RESULTS: IL-6-induced STAT3 transactivation and SOCS3 production were significantly repressed by metformin, adenoviral constitutively active AMPK (Ad-CA-AMPK), and adenoviral SHP (Ad-SHP), but not in Shp knockdown, or with the adenoviral dominant negative form of AMPK (Ad-DN-AMPK). Chromatin immunoprecipitation (ChIP), co-immunoprecipitation (Co-IP) and protein localisation studies showed that SHP inhibits DNA binding of STAT3 on the Socs3 gene promoter via interaction and colocalisation within the nucleus. Upregulation of inflammatory genes and downregulation of hepatic insulin signalling by acute IL-6 treatment were observed in wild-type mice but not in Shp null mice. Finally, chronic IL-6 exposure caused hepatic insulin resistance, leading to impaired insulin tolerance and elevated gluconeogenesis, and these phenomena were aggravated in Shp null mice. CONCLUSIONS/INTERPRETATION: Our results demonstrate that SHP upregulation by metformin may prevent hepatic disorders by regulating the IL-6-dependent pathway, and that this pathway can help to ameliorate the pathogenesis of cytokine-mediated metabolic dysfunction.

Development of QSAR model for immunomodulatory activity of natural coumarinolignoids.

Immunomodulation is the process of alteration in immune response due to foreign intrusion of molecules inside the body. Along with the available drugs, a large number of herbal drugs are promoted in traditional Indian treatments, for their immunomodulating activity. Natural coumarinolignoids isolated from the seeds of Cleome viscose have been recognized as having hepatoprotective action and have recently been tested preclinically for their immunomodulatory activity affecting both cell-mediated and humoral immune response. To explore the immunomodulatory compound from derivatives of coumarinolignoids, a quantitative structure activity relationship (QSAR) and molecular docking studies were performed. Theoretical results are in accord with the in vivo experimental data studied on Swiss albino mice. Immunostimulatory activity was predicted through QSAR model, developed by forward feed multiple linear regression method with leave-one-out approach. Relationship correlating measure of QSAR model was 99% (R(2) = 0.99) and predictive accuracy was 96% (RCV(2) = 0.96). QSAR studies indicate that dipole moment, steric energy, amide group count, lambda max (UV-visible), and molar refractivity correlates well with biological activity, while decrease in dipole moment, steric energy, and molar refractivity has negative correlation. Docking studies also showed strong binding affinity to immunomodulatory receptors.

Hepatoprotective Effects and Safety Evaluation of Coumarinolignoids Isolated from Cleome viscosa Seeds.

The aim of the present work was to investigate the in vivo hepatoprotective potential of coumarinolignoids (cleomiscosins A, B, and C) isolated from the seeds of C. viscosa. The study was performed against CCl(4)-induced hepatotoxicity in albino rats. Rats were divided into four groups. The animals of group I served as normal and was given only vehicle. Group II served as toxin control and administered with CCl(4) (50% solution liquid paraffin, 2 ml/kg intraperitoneally). The animals of group III received coumarinolignoids (50 mg/kg) for six days orally as well as CCl(4) (2 ml/kg) on 4(th) day i.p. Similarly animals of group IV received silymarin (50 mg/kg) for six days orally as well as CCl(4) on 4(th) day i.p. On 7(th) day various parameters viz. serum glutamyl oxaloacetic transaminase, serum glutamyl pyruvate transaminase, serum alkaline phosphatase, serum bilirubin, liver glycogen were estimated and histopathology was performed. Additionally, acute oral toxicity of the said coumarinolignoids was carried out in swiss albino mice. The coumarinolignoids were found to be effective as hepatoprotective against CCl(4)-induced hepatotoxicity as evidenced by in vivo and histopathological studies in small animals. Safety evaluation studies also exhibit that coumarinolignoids are well tolerated by small animals in acute oral toxicity study except minor changes in red blood cell count and hepatic protein content at 5000 mg/kg body weight as a single oral dose. Coumarinolignoids which is the mixture of three compounds (cleomiscosin A, B and C) is showing the significant protective effects against CCl(4)-induced hepatotoxicity in small animals and also coumarinolignoids are well tolerated by small animals in acute oral study.

Outcomes of respiratory diphtheria in a tertiary referral infectious disease hospital.

BACKGROUND: Diphtheria is a fatal disease and may cause serious complications if not recognized early and treated properly. OBJECTIVES: To study the epidemiology, clinical features, complications, and outcomes in respiratory diphtheria. MATERIALS AND METHODS: Diphtheria cases admitted in the infectious disease hospital, Beliaghata, Kolkata, India between January 2009 to January 2011 were evaluated in respect to demographic profile, immunization status, clinical features, complications, and outcomes. RESULTS: 200 diphtheria cases were studied. 150 (75%) patients had history of an adequate immunization, and 100 (50%) patients were from lower socio-economic groups. Common clinical features observed were throat pain in 148 (74%) cases and fever in 112 (56%) cases. Complications observed were myocarditis in 136 (68%) cases, neuropathy in 30 (15%) cases, and respiratory compromise in 14 (7%) cases. Death occurred in 5 (2.5%) patients. CONCLUSIONS: diphtheria is still a public health problem in many developing countries. Strict public health measures like an increased immunization coverage, improvement of socio-economic status, easy availability of anti-diphtheritic serum (ADS), early recognition and effective treatment-all may reduce the incidence and mortality.

Antitubercular potential of some semisynthetic analogues of phytol.

Phytol, a diterpene alcohol was modified to several semisynthetic analogues. Some of the modifications were done logically to enhance lipophilicity of the molecule. Analogues 14, 16 and 18 exhibited antitubercular activity (MIC 15.6-50microg/mL) better than phytol (100microg/mL). The most potent analogue 18 was evaluated for in vivo toxicity in Swiss albino mice and was well tolerated by the experimental animals up to 300mg/kg body weight as a single oral acute dose.

Fluorescence properties of donor acceptor chromophores on newly synthesized pyridine-3-carbonitriles.

A convenient route was successfully developed for the synthesis of novel heterocycles such as pyridine-3-carbonitriles 4 from chalcone 3 in good yields. The pyridine-3-carbonitrile derivatives synthesized were further studied for their photophysical properties and observed that absorption and emission was changed, due to the chromospheres at C4-position in phenyl ring and C2-position in pyridine-3-carbonitrile derivatives.

Cancer gene therapy using mesenchymal stem cells expressing interferon-beta in a mouse prostate cancer lung metastasis model.

Cell-based therapy for cancer is a promising new field. Among cell types that can be used for this purpose, mesenchymal stem cells (MSCs) appear to hold great advantage for reasons including easier propagation in culture, possible genetic modification to express therapeutic proteins and preferential homing to sites of cancer growth upon in vivo transfer. The present study evaluated the potential of genetically modified MSC, constitutively expressing interferon (IFN)-beta, in an immunocompetent mouse model of prostate cancer lung metastasis. A recombinant adeno-associated virus (rAAV) encoding mouse IFN-beta was constructed and initially tested in vitro for high-level expression and bioactivity of the transgenic protein. MSCs were transduced by the rAAV-IFN-beta or green fluorescent protein ex vivo and used as cellular vehicles to target lung metastasis of TRAMP-C2 prostate cancer cells in a therapy model. Cohorts of mice were killed on days 30 and 75 to determine the effect of therapy by measurement of tumor volume, histology, immunohistochemistry, enzyme-linked immunosorbent assay and flow cytometry. Results indicated a significant reduction in tumor volume in lungs following IFN-beta-expressing MSC therapy. Immunohistochemistry of the lung demonstrated increased tumor cell apoptosis and decreased tumor cell proliferation and blood vessel counts. A significant increase in the natural kill cell activity was observed following IFN-beta therapy correlating the antitumor effect. Systemic level of IFN-beta was not significantly elevated from this targeted cell therapy. These data demonstrate the potential of MSC-based IFN-beta therapy for prostate cancer lung metastasis.

Therapeutic potential of genetically modified mesenchymal stem cells.

Bone marrow-derived mesenchymal stem cells (MSC) are multipotent adult stem cells of mesodermal origin localized within the bone marrow compartment. MSC possess multilineage property making them useful for a number of potential therapeutic applications. MSC can be isolated from the bone marrow, expanded in culture and genetically modified to serve as cell carriers for local or systemic therapy. Despite their ability to differentiate into osteoblasts, chondrocytes, adipocytes, myocytes and neuronal cells under appropriate stimuli, distinct molecular signals that guide migration of MSC to specific targets largely remain unknown. The pluripotent nature of MSC makes them ideal resources for regenerative medicine, graft-versus-host disease and autoimmune diseases. Despite their therapeutic potential in a variety of diseases, certain issues need to be critically addressed both in in vitro expansion of these cells without losing their stem cell properties, and the long-term fate of the transplanted MSC in vivo following ex vivo modifications. Finally, understanding of complex, multistep and multifactorial differentiation pathways from pluripotent stem cells to functional tissues will allow us to manipulate MSC for the formation of competent composite tissues in situ. The present article will provide comprehensive account of the characteristics of MSC, their isolation and culturing, multilineage properties and potential therapeutic applications.

Post-therapy profile of serum total cholesterol, retinol and zinc in pediatric acute lymphoblastic leukemia and non-Hodgkin's lymphoma.

OBJECTIVE: To assess serum albumin, total cholesterol, retinol, zinc and hemoglobin in children who had completed treatment for acute lymphoblastic leukemia (ALL) and Non-Hodgkin's lymphoma (NHL). METHODS: The above parameters were analyzed in 105 ALL and NHL and 108 age and sex-matched controls. Serum albumin, serum cholesterol and hemoglobin were estimated by colorimetric methods. Serum retinol was estimated by HPLC and serum zinc was estimated by atomic emission spectrophotometer (ICP-AES). Comparisons were made to stage of treatment (maintenance 6 with post-therapy), type of treatment (chemotherapy and radiation with only chemotherapy) and type of malignancy (ALL with NHL). RESULTS: Only serum albumin in patients included at Maintenance(6) was significantly higher (t = 2.31, p = 0.05) than post-therapy patients. No significant difference in serum values was observed by type of treatment. Only total cholesterol was significantly higher in NHL patients than in ALL patients (t = 1.954, p = 0.05). Patients had comparable serum levels to that of controls. However, in patients and controls more than 75% children had deficient serum retinol levels, (< than 0.6989 micromol/l, or 20 microg/dl). Further, 75% patients and 54.7% controls had serum retinol levels less than 0.3439 micromol/l or 10 microg/dl. CONCLUSION: The results of the present study indicate that cancer and its treatment did not have any long-lasting effect on serum albumin, total cholesterol, retinol, zinc and hemoglobin. Majority of subjects had low serum retinol suggestive of depleted liver reserves. The deficient serum retinol levels (< than 0.6989 micromol/l, or 20 microg/dl) in at least 75% of the patients and controls probably reflect poor dietary intake. A higher percentage of patients with low serum retinol levels may also be attributed to the possibility of urinary losses of retinol that occur during episodes of infection while on immunosuppressive anti-cancer drug therapy.

Pattern of ovarian protein synthesis and secretion during the reproductive cycle of Scotophilus heathi: synthesis of an albumin-like protein.

Ovarian proteins synthesized de novo and secreted in vitro were investigated during different stages of the reproductive cycle of Scotophilus heathi. We found increased ovarian protein synthesis and secretion during the recrudescence and the preovulatory periods, coinciding with two peaks of follicular development and steroidogenesis. The ovaries synthesized protein at a low rate during quiescence and the late phase of delayed ovulation. In vitro analysis using 35 S-methionine incorporation showed increased synthesis of 66 kDa protein during delayed ovulation, but secretion of this protein declined markedly during the preovulatory period. N-terminal sequencing of the 66 kDa protein showed that it shares 70% homology with human serum albumin. Immunocytochemistry indicated that this protein is found primarily in the granulosa cells of the follicles. Whether the increase in albumin production by the ovaries during delayed ovulation is associated with a hyperinsulinemic and hyperandrogenic condition requires further investigation.

Changes in circulating insulin and corticosterone concentrations during different reproductive phases and their relationships to body weight and androstenedione concentration of male Scotophilus heathi.

The aim of the present study was to determine the serum levels of insulin and corticosterone during different reproductive stages in a natural population of the male bat, Scotophilus heathi and their relationship to body weight and androstenedione level. Changes in body weight were marked by weight gain before winter dormancy and weight loss during winter dormancy. Circulating insulin level varied significantly over the season and correlated positively with changes in body weight and androstenedione level. Circulating corticosterone level also varied significantly over the season but correlated negatively with changes in body weight and androstenedione level. High corticosterone level during August coincided with a period of increased feeding activity in this species. The results suggest that insulin may act as an anabolic agent to promote fat deposition and corticosterone exerts a predominantly fat-mobilizing influence. A high insulin level prior to winter dormancy may be an important factor responsible for inducing high androstenedione concentration shown in Scotophilus heathi.