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A review of the virulence factors of pathogenic fungi

C. Iyalla

 

Abstract

Fungal infections are becoming more prevalent especially with increase in immunodeficiency disorders, immunosuppression following transplantation, cancers and cancer treatment. They are ubiquitous and cause infections which may be trivial or more deep seated and severe infections associated with mortality. The ability of some fungal species to cause disease is due to various virulence factors which help with fungal survival and persistence in the host resulting in tissue damage and disease. This review discusses these virulence factors. These factors include an ability to adhere to hosts’ tissues, production of enzymes that cause tissue damage and direct interference with host defences. Pathogenic fungi produce catalases and Mannitol which protect against reactive oxygen species (ROS). Some fungi notably, dimorphic fungi and C. albicans have the ability to switch from one form to another. Thermotolerance, at least to 370C, is critical for survival in mammalian host and contributes to dissemination. Melanin is produced by a number of pathogenic fungi, and protects against harsh conditions such as UV radiation, increased temperature and ROS. The ability to obtain Iron (Fe) from the storage or transport forms in the host is also a virulence factor and calcineurin acts as a sensor for pathogenic fungi.

Keywords: Fungi, virulence, pathogenic, infections, dimorphism, thermotolerance

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A review of the virulence factors of pathogenic fungi

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Trends in profiles of bacteria causing neonatal sepsis in Central Nigeria Hospital

N. Medugu, K.C. Iregbu

 

Abstract

Developing countries suffer from a huge burden of neonatal sepsis. Neonatal  mortality and long term sequelae or morbidity portends huge costs for the poor Nigerian economy. We identified trends in bacterial agents implicated in neonatal sepsis and their antibiotic susceptibility profiles at the National Hospital Abuja over two periods of three years each a decade apart. A retrospective study of bacterial agents of sepsis from 2013-2015 was carried out and this was compared to an already published study from the same hospital ten years earlier(2002-2004) to determine changing trends using standard statistical methods. We identified a significant shift to predominance of gram positive organisms especially Staphylococcus aureus (59% vs 40%) as against the predominance of gram negative organisms especially Klebsiella pneumoniae (11% vs 44%) in the previous decade. Almost all antibiotics tested (92%) had reduced susceptibility in the later review compared to the former. Surveillance of bacterial agents of neonatal sepsis is vital for the detection of trends in causative organisms and their susceptibilities. This is important to direct empiric therapy and also to encourage implementation and monitoring of antibiotic stewardship programs.
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Comparing antibody responses to Onchocerca volvulus and non-parasite antigens in placebo-controlled and ivermectin-treated onchocerciasis patients

H.O Osue, F.N.C Enwezor, B.T. Idowu, A. Cassel-Brown, B. Jones, A. Abiose, F Engelbrecht, H. Edeghere

 

Abstract

Serum antibodies to parasite-specific and non-parasite antigens were evaluated  using enzyme-linked immunosorbent assay (ELISA). Out of the 470 sera collected, 409 were from residents of an onchocerciasis hyper-endemic area, 55 non-endemic and 6 European normal sera served as control. The patients’ age, sex, skin  microfilaria densities, dermal and ocular clinical manifestations (colour of optic disc) have been well characterised. The study population had participated in a  placebocontrolled (n=191) trial of ivermectin (Mectizan®) treatment (n=218). The parasite antigens are phosphate buffered saline crude extract of adult worms of Onchocerca volvulus, a recombinant antigen (Ov1.9) and a monoclonal antibody purified antigen (Cam 1). The non-parasite antigens are deoxycholate citrate extract of optic nerve (nerve-DOC) and commercially available IgA, IgM and IgG were used to assay for rheumatoid factor (Rh-F) auto-antibodies. Generally, antibodies to parasite antigens in onchocerciasis patients were remarkably higher than control group (p<0.05) using exact F-test. There was no significant difference (p>0.05) in antibodies to nerve-DOC and Rh-F in patients compared to control. Antibodies increased with increasing skin snip microfilaria load from 0.69±0.28 with 0mf/mg (n=54) as against 0.80±0.26 for those with 4-20mf/mg. Observed slight negative correlation in IgG antibody levels and severity of disc colour with mean OD values of 0.26±0.22 in those graded as having no optic nerve disease (OND) (disc 1, n=86) and 0.17±0.19 for those with severe changes (disc 3, n=49) was not statistically significant (P>0.05). An age dependent significant decrease (P<0.05) in antibodies were observed with 0.64±0.34 for 15-30yr old (n=48) compared to 0.48±0.35 for those 50yr (n=50) for PBS with a similar trend for IgG to Ov1.9 and Cam1. In conclusion, serum parasite-specific and non-parasite antibodies may not be responsible for the pathology of optic nerve disease. Onchocerciasis patients were apparently not at higher risk of developing rheumatoid arthritis than the control.

Keywords: Onchocerciasis; Antibodies; Antigens; Immune responses; Ivermectin.

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Comparing antibody responses to Onchocerca volvulus and non-parasite antigens in placebo-controlled and ivermectin-treated onchocerciasis patients

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Public health practices at meat pie retail points in Makurdi, Benue State and its potential effect on consumer’s health

G.A. Obande, E.U. Umeh, E.T. Azua, C. Aleruchi, P. Adikwu

 

Abstract

Observance of public health best practices at point of sales by meat pie retailers in Makurdi, Benue State was evaluated by studying three (3) retail sources namely eateries, supermarkets and street hawkers. Observations were carried out ninety (90) times between March to July 2013. The neatness of the vendor, sales  environment, and state of the product storage containers were assessed.  Microbiological analysis revealed the presence of Staphylococcus aureus, Escherichia coli, Staphylococcus spp, Enterobacter spp, Proteus spp, Pseudomonas spp, Citrobacter spp, Edwardsiella spp, Bacillus spp, Klebsiella spp and Shigella spp. There was a positive relationship between multiple bacterial contamination and the constituents of the meat pie fillings. A total of 64 (35.6%) fillings had between 3 – 7 bacterial contaminants, 57 (31.7%) had at least 2 bacterial contaminants, 58 (32.2%) had at least 1 contaminant while only 1 (0.6%) was without any bacterial contaminant. Only 5(5.6 %) of the vendors and 10(11.1%) of the sales environment were very neat, while 23(25.6%) and 22(24.4%) of the storage containers were observed to be partially accessible to air/dust and insects respectively. None of the vendors (90:100%) used hand gloves, none (90:100%) used an apron, 89 (98.9%) used no cutlery and 89 (98%) had uncovered hair while serving the product. The paper submits that the health of consumers is endangered by this negligence. Hence, the need for regulatory authorities to create awareness on, as well as enforce the observance of established point of sales practices for the sake of the public health.

Keywords: Public, health, meat pie, fillings, negligence, contamination.

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Public health practices at meat pie retail points in Makurdi, Benue State and its potential effect on consumer’s health

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Pattern of bacterial pathogens of acute Otitis media in a tertiary hospital, South Western Nigeria

S.A. Fayemiwo, R.A. Ayoade, Y.O. Adesiji, S.S. Taiwo

 

Abstract

Introduction: Otitis media was reasonably prevalent prior to the use of antibiotics for treatment. In Nigeria, hospital incidence reports indicate that chronic suppurative Otitis media is the commonest. Complications that usually arise as a result of untreated Otitis media are meningitis, brain abscess, keratoma, otosclerosis, and hearing loss. The study aimed at providing information on the pattern of bacterial pathogens of acute Otitis media in LAUTECH Teaching hospital, Osogbo, Nigeria.

Methods: It was a cross-sectional study involving patients with acute Otitis media attending ENT clinic at LAUTECH Teaching Hospital, Osogbo, Nigeria. Ear swabs were collected from the patients after informed consent. The samples were inoculated on general and selective laboratory media. Bacterial pathogens were isolated and identified. Antibiotic susceptibility testing was performed on each of the bacterial isolates using modified Kirby Bauer disk diffusion.

Results: There were 115 isolates from 98 patients with acute Otitis media. Gram negative bacteria constituted 66.7% of the isolates. The most common organism was Pseudomonas aeruginosa (34.8%). Others were Staphylococcus aureus (30.4%), Proteus spp (15.7%), Klebsiella spp (11.3%), Escherichia coli (2.6%) and few Fungi (4.1%). Antibiotics sensitivity results of the isolates showed high resistance against most readily available antibiotics. The cumulative resistance of all the bacteria isolates to Augmentin was 89%, gentamicin 80%, ciprofloxacin 34% and ceftazidime 10%. About 88% of the Gram positive bacteria were resistant to penicillin G, amoxicillin, cotrimoxazole, and erythromycin. While 100% of the Gram negative bacteria were resistant to cotrimoxazole, tetracycline, and chloramphenicol. However, commonly isolated organisms were highly susceptible to few 3rd-generation cephalosporins especially ceftriaxone and ceftazidime.

Conclusion: Based on the result of this study, it is suggested that knowledge of antibiotic profile of etiological agents in Otitis media would be of great advantage in reducing the morbidity and mortality associated with Otitis media.

Keywords: Otitis media, Bacterial agents, Antibiotic resistance

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Pattern of bacterial pathogens of acute Otitis media in a tertiary hospital, South Western Nigeria

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The etiology and antimicrobial susceptibility patterns of urinary tract infections at a private Nigerian teaching hospital in South West Nigeria

C.J. Elikwu, E.O. Shobowale, O.Y. Oluyemi, D.O. Afolabi, D.A. Aderinto, K.I. Onyedibe, A.U. Solarin

 

Abstract

Background: Urinary tract infections (UTI’s) are among the commonest bacterial infectious disease in clinical practice with a wide range of etiologic agents. It frequently occurs in both the hospital and the community.

Aims/Objectives: To determine the etiology of UTI at BUTH and obtain data on their susceptibility and resistance patterns.

Methods: This was a prospective analysis of data on patients with UTI obtained from in and outpatients over a six month period. Samples had been obtained by clean catch mid-stream urine or suprapubic aspiration. The organisms had been
identified by biochemical methods with susceptibility and resistance testing performed. Data analysis was with EPI-INFO version 3.5.1

Results: There were a total of 200 urine samples that had positive growth. Prevalent organisms were Escherichia coli (48%) and Klebsiella spp (24%), followed by Staphylococcus aureus (10%) and Coagulase Negative Staphylococci (6.5%). The risk factors for UTI were female gender (p = 0.00), Diabetes mellitus (p = 0.03) and genitourinary surgery (p = 0.04). Effective antibiotics in-vitro to Escherichia coli were Nitrofurantoin and Cefepime at 84.8% and 92.3% respectively; while Cotrimoxazole performed poorly (32.5% susceptibility).

Conclusion: Urinary tract infections are an important cause of morbidity in our environment and inaccuracies in diagnosis will prolong morbidity and may lead to costly and unsafe treatments.The prevalent pathogens in our environment are the Gram negative bacilli, Escherichia coli andKlebsiella pneumoneae. Nitrofurantoin retains efficacy to both urinary pathogens.

Keywords: Urinary Tract Infection, Catheterization, Escherichia coli, Risk factors, Nitrofurantoin

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The etiology and antimicrobial susceptibility patterns of urinary tract infections at a private Nigerian teaching hospital in South West Nigeria

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Epidemiologic characteristics of Klebsiella pneumoniae isolates in ventilator-associated pneumonia in intensive care units

A.A. El Sharkawy, M.A. Mansour, H.M. Helmy, D.M. Abd El Azeem

 

Abstract

Klebsiella pneumoniae is a common pathogen that causes ventilator associated pneumonia (VAP) in intensive care units (ICUs). Strain typing is a useful tool in tracking the spread of these infections. Primary objective was to study different strains causing VAP in Anesthesia ICUs. Secondary objective was to determine role of health-care workers (HCWs) and ICU environment in the transmission of these strains. Endotracheal aspirates of 60 VAP patients, surveillance samples from the HCWs (18 )and the ICU environment (193)were collected. Antibiogram typing and enterobacterial repetitive intergenic consensus-polymerase chain reaction (ERIC-PCR) were used for comparison of the isolates from VAP patients and surveillance samples. Antibiogram showed 5 antibiotic susceptibility patterns that were designated A1-A5. ERIC-PCR yielded 1 to 5 amplification bands. All the isolates were typable by ERIC-PCR. Eight ERIC patterns were obtained ERIC(I)-ERIC(VIII). ERIC-PCR typing method gave higher discriminatory index (D) (0.7557) than antibiogram (0.6035). There was sharing of certain ERIC patterns among patient and HCWs or environmental sources. In Conclusion: K.pneumoniae is the most dominant pathogen in anesthesia ICUs. Throats and hands of HCWs are possible sources of pathogen transmission to patients. Surfaces with hand contact of the medical staff are often contaminated and may serve as vectors for cross transmission.

Keywords: Ventilator-associated pneumonia, ICU environment, health-care workers, Klebsiella pneumoniae, antibiogram typing, ERIC-PCR

Epidemiologic characteristics of Klebsiella pneumoniae isolates in ventilator-associated pneumonia in intensive care units

 

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In vitro and in vivo antimicrobial activity of partially purified enterocin produced by Enterococcus faecalis and its application in wound healing

O.M. David, M.O. Alese, D.M. Komolafe, I.J. Adejare, O.O. Alese, A.E. Omonisi

 

Abstract

Background: The recent global upsurge in antibiotic resistance among bacteria associated with wounds has contributed to high treatment failures in wound management. Enterocin are produced by enterococci and has been reported to inhibit the growth of many bacteria including those associated with wound infections.

Objectives: In this study, antibacterial and physico-chemical properties of partially purified enterocin (PPE) from Enterococcus faecalis was determined. Also, the possible application of the enterocin in wound management was evaluated.

Materials and Methods: Eight different enterocin were tested and that with highest antibacterial (E3) was partially purified using standard methods. The molecular weight of the PPE was determined by sodium dodecyl sulphate polyacrylamide gel electrophoresis after which the in vitro anti-Staphylococcus aureus potential of the PPE was determined.

Results: Enterocin (E3) was effective against Staphylococcus aureus, Klebsiella pneumoniae, Enterobacter cloaca, Listeria monocytogenes and Proteus vulgaris. The activity of the E3 was very prominent at pH of 4 and 8. The molecular size of the isolated enterocin was 5.5 KDa. The photomicrograph of the skin tissue of the skin treated with partially purified enterocin for day 7showed epidermis covered by atrophic stratified squamous epithelium. A synergistic interaction was noticed when Eusol was used with the enterocin.

Conclusions: From this study, enterocin from E. faecalis has a low molecular weight and inhibited bacteria isolates from wound and also aids physiological healing of wound.The antibacterial potency of this bacteriocin indicates that it is an alternative therapeutic agent that can be employed in wound care and management.

Keywords: Enterocin, Enterococcus faecalis, wounds, bacteriocin, Staphylococcus aureus, skin

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In vitro and in vivo antimicrobial activity of partially purified enterocin produced by Enterococcus faecalis and its application in wound healing