Microbiol. Res., Volume 3, Issue 2 (July 2012) – 11 articles

We report here a case of a 32-year old female with a history of minor trauma presented with total corneal ulcer and hypopyon in the left eye. Microbiological examination of corneal scraping showed refractile hyphae with asepted branching filaments and black pigmented colonies in multiple solid agar medium. Identification of the organism was made from culture using D1/D2 region of Large Sub Unit (28S rDNA) based molecular technique. Polymerase chain reaction amplified a band with a sequence that was 100% homologous with Lasiodiplodia theobromae. The organism was sensitive to amphotericin B and voriconazole, and demonstrated resistance to itraconazole and fluconazole. Therapeutic keratoplasty was performed followed by recurrence in graft controlled with topical voriconazole and intracameral amphotericin B. Graft failure was reported after three months. Full article

Water used for domestic purposes is ideally required to be free from contaminants. Various contaminants have frequently affected the quality of such water. Water samples were obtained from 150 sources including 72 wells, 60 streams, 17 taps, and one borehole, randomly selected from five residential areas in Jos, Nigeria. Structured questionnaires and one-to-one interview was used to obtain information on features of location and use of facilities in each area. Eighty (53.3%) water sources were contaminated, predominantly wells (70.8%). The locations (identified in code) with the highest number of contaminated sources were AGO (60.0%), GBU (56.7%) and FGD (56.7%). AGD and FGD also had the highest ratio of households to one water source (25:1). Eighty-two fungi were isolated, predominantly Candida tropicalis (23.2%), Candida lipolytica (10.9%) and Rhodotorula sp (9.7%). Candida lipolytica was the highest (42.9%) contaminant in tap water. Rhodotorula sp was found in all types of water sources sampled. Type of water source had a significant effect (P < 0.05) on the presence of some fungi in the water. The residential area (Location) had a significant effect on contamination of water sources by some yeasts. Water sources for domestic use in Jos are contaminated by yeasts and yeast-like fungi. Frequency of use, exposure of the facility to dirt, and contaminations of surroundings contribute to the occurrence of fungi in water sources and, by implication, the prevalence of fungal infections. Full article

The influence of sodium chloride (NaCl) treatment on the antifungal activity of the bacterium Pseudomonas aurantiaca, a producer of biopesticide for vegetable plants, was investigated. It was shown that an increase in the NaCl concentration in incubation solutions from 1 M to 3 M led to a significant increase in the antifungal activity of this bacterium. Antifungal activity continued to increase with prolonged treatment of bacteria in fresh nutrient medium from 72 h to 96 h. These findings could be very important for the further development of biotechnological processes directed not only to the production of new active biopesticides but also of other valuable resources. Full article

The genus Staphylococcus contains many pathogenic strains that are difficult to differentiate. Given the absence of a specific immunological test to identify autochthonous species, we have characterized soluble antigens (SAgs) using hyperimmune sera from BABL/c mice. Ten samples were taken from the farmers’ hands and cattle udders on three different farms. The isolated species were identified using the API kit (Staph) and their ability to form biofilms was determined. The species most commonly found in the isolates (90%) corresponded to the coagulase-negative bacteria and Staphylococcus sciuri (S. sciuri), which presented the ability of biofilm formation, representing the majority (60%) in this group. We produced SAgs from those Staphylococcus species present in a higher frequency, such as S. sciuri, S. aureus, and the reference strain, S. aureus ATCC 6835. Polyclonal antibodies (PAb) from mice allowed SAgs characterization by enzyme-linked immunoassay (ELISA) and immunoblotting. The humoral response obtained with the PAb by indirect ELISA tests indicated that our hyperimmune sera have a high recognition for all SAgs produced. We also evaluated the hyperimmune sera cross-reactivity between different SAgs by indirect ELISA and immunoblotting assays. The ELISA experiments showed a significant statistical difference in the recognition of S. sciuri when compared to SAgs from S. aureus. These results showed a high antigenicity and specificity from S. sciuri SAgs in immune tests. We identified a specific immunodominant polypeptide of ~31 kDa (p31) from S. sciuri SAg, which do not presented cross-reactivity between different SAgs. We concluded that the p31 polypeptide from S. sciuri SAg could be used as antigen in a differential diagnosis test for different staphylococcal species. Full article

The aim of the study was to determine the effective pH of calcium hydroxide Ca(OH)₂ against Enterococcus faecalis, the most frequently isolated bacterial species in endodontic failure. Solutions of Ca(OH)₂ with different pH values of 9, 11 and 12.5 were prepared by dissolving 1 mg of Ca(OH)₂ in distilled water. The test solutions were grouped as follows: Group I, vials containing phosphate buffered saline pH of 7.2 as control; Group II, aqueous calcium hydroxide with pH of 9; Group III, aqueous calcium hydroxide with pH of 11; Group IV, aqueous calcium hydroxide of pH 12.5.Forty sterile paper points were transferred to Trypticase Soy Agar broth containing Enterococcus faecalis for a period of 10 min, then transferred to vials containing 1 mL of the test solutions and incubated for 1 h at 37 °C. The paper points were then transferred to neutralizing broth with glass beads to resuspend the microorganisms. Ten-fold serial dilutions were performed using aliquots of 250 μL from the broth and the same amount was plated onto blood agar plates. The plates were incubated anaerobically at 37 °C for 24 h. The number of colony forming units for each dilution was counted using the colony counter. The inhibitory effects of different pH groups on the bacteria were as follows: Group IV > Group III > Group II > Group I in an ascending order. This study revealed that Ca(OH)₂ at a pH 12.5 was effective in complete elimination of Enterococcus faecalis. Full article

Neurotoxin complex (NTC) genes are arranged in two known hemagglutinin (HA) and open reading frame X (ORFX) clusters. NTC genes have been analyzed in four serotypes A, B, E and F of Clostridium botulinum causing human botulism. Analysis of amino acid sequences of NT genes demonstrated significant differences among subtypes and four serotypes. Phylogram tree of NT genes reveals that serotypes A1 and B1 are much closer compared to serotype E1 and F1. However, non-toxic non-hemagglutinin (NTNH) gene is highly conserved among four serotypes. Analysis of phylogram tree of NTNH gene reveals that serotypes A and F are more closely related compared to serotype B and E. Additionally, sequences of HAs and ORFX genes are very divergent but these genes are specific in subtypes and serotypes of Clostridium botulinum. Information derived from sequence analyses of NTC has direct implication in development of detection tools and therapeutic countermeasures for botulism. Full article

Over the last four decades, methicillin-resistant Staphylococcus aureus (MRSA) has spread throughout the world and become highly endemic in many geographical areas. This pathogen causes severe morbidity and mortality in hospitals worldwide. MRSA is also considered a major community acquired pathogen throughout the world. MRSA is implicated in serious clinical conditions such as bacteremia, pneumonia, and intra-abdominal infection. The objective of this study was to determine the prevalence of MRSA in Accra, Ghana, and also to determine its antibiotic susceptibility profile. Two hundred and fifty Staphylococcus aureus isolates from routine microbiological specimens were collected from five hospitals in Accra. MRSA screening assay was used to screen for MRSA. Disc diffusion method (Kirby-Bauer) was used to determine the susceptibility of the MRSA. The MRSA screening assay, which is very close to the polymerase chain reaction in terms of specificity and sensitivity, showed that 84 of the 250 isolates were MRSA, giving a prevalence rate of 33.6%. MRSA strains were susceptible to erythromycin; 63 out of the 84 MRSA isolates were susceptible representing 75%. This was followed by gentamicin 46 (54.7%), cotrimoxazole 35 (49%), cefuroxime 33 (38%), flucloxacillin 24 (28.6%), and ampicillin 13 (15.5%). Penicillin 4 (4.8%) and tetracycline 6 (7.1%) were the least susceptible. The findings from this study emphasize the need for continual surveillance of MRSA and of antibiotic resistance in general. Full article

Streptomyces roseoflavus Men-myco-93-63 was isolated from potato scab (S. scabies) decline soil as an antagonistic strain, which can effectively inhibit several phytopathogenic fungi and control important related plant diseases. In this study, cosynthesis and different expression protein analysis between seven antibiotic synthesized-blocked mutants of Men-myco-93-63 were carried out. Two-dimensional gel electrophoresis was used to compare proteins of cosynthesis and non-cosynthesis mutants. By matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, two different protein spots were isolated and identified to be homologous proteins of ectoine hydroxylase and transcriptional regulator (DeoR family protein), which could be related to the biosynthesis of antibiotics of S. roseoflavus Men-myco-93-63. Full article

A combination of at least three hemagglutination-inhibition-positive (HAI) and virus-specific (Hs) monoclonal antibodies (MAbs) to glycoprotein E (gpE) of Japanese encephalitis virus (JEV) fully protected (100%) mice against JEV strain 733913 infections (group 1). However, these representative epitopes are reported to have been lost on JEV group II strains. In the present study, therefore, the protective effect of various combinations of anti-gpE MAbs representing antigenic epitopes other than Hs was studied on mice infections with JEV group II strains: JEV strains 641686 and 691004. MAbs used in the protective experiments were characterized as HAI-negative virus-specific (NHs) and HAI-positive flavivirus cross-reactive (Hx). Additionally, one of the Hs MAbs (MAb Hs-3) was included in the experiments. Mice were first administered single MAbs or their combinations intraperitoneally and 24 h later, infected with the virus intracerebrally. Protection rates of 70–75% were obtained with a combination of four MAbs: MAbs NHs-1, Hx-1, Hx-3 and Hs-3. However, protection rates of only 20–40% were obtained with three MAbs but none was observed with single or two MAbs. There was, however, a substantial increase in mice survival. The protective effect of several combinations of anti-gpE MAbs representing different antigenic epitopes might be due to the enhancement of binding within the same group and also between different MAb groups. The present results indicate that NHs and Hx epitopes should be incorporated with three Hs epitopes in a JEV vaccine that would have an added advantage, particularly in the flaviviral endemic areas with JEV strain variations. Full article

An epidemiological survey and evaluation of the anti-bacterial growth effect of the aqueous leaf extract of the traditional medicinal plant Rhazya stricta were undertaken for extended-spectrum β-lactamase’s producing bacteria isolates collected from the King Abdulaziz Hospital and Oncology Center. Results showed high rates of extended-spectrum β-lactamase (ESBL) isolates (49.2%) compared to non-ESBL isolates (50.8%). The surgical intensive care unit was the hospital site showing the highest rate (15.1%) of infection, followed by the women's medical ward (11.2%). Urine samples were the highest source of infection (40%). Prevalence among Saudis was 66.67% as compared to non-Saudis (33.33%). Prevalence according to gender was 51.94% females and 48.06% males. Age groups 51-60 years, 21-30 years, and 61 years and over showed the highest rates (20.93%, 20.54% and 20.16%, respectively) compared with other age groups. E. coli resistance rates were 94.5% for ceftazidime, 98.18% for cefotaxime, 92.73% for cefepime and 93.75% for aztreonam. On the other hand, in cases of K. pneumoniae resistance, rates were 100% for ceftazidime, 100% for cefotaxime, 98.68% for cefepime and 97.29% for aztreonam. Genetic analysis showed 8 genotypes, 4 of them were for E. coli and 4 for K. pneumoniae. Analysis also showed genetic diversities between the ESBL and the non-ESBL types in their genomic DNA. There was no antimicrobial effect of the plant extract against all study isolates, although the antimicrobial growth had an effect upon some of the control strains. Full article

The role of chronic infections in causing coronary artery disease (CAD) has been investigated for the past several years. Among them, the role of Helicobacter pylori has stimulated keen interest. Though initial results were conflicting, there are growing data to support the role of H. pylori in CAD. The main mechanism of endothelial damage is hypothesized to be through molecular mimicry involving heat shock proteins. This study was designed to determine the prevalence of H. pylori and cytotoxin associated gene A (cagA) positive H. pylori infection in patients undergoing coronary artery bypass grafting (CABG) and the potential role of anti-H. pylori specific heat shock protein-60 (Hp-HSP-60) antibody response in these patients, for cardiac events. One hundred patients undergoing CABG and 100 controls were studied. The H. pylori infection and cagA status were determined serologically by enzyme-linked immunosorbent assay (ELISA). Hp-HSP-60 Immunoglobulin G (IgG) antibodies were estimated by using an in house ELISA. Although there was no difference in the prevalence of H. pylori infection in patients and controls (74% vs 70%), 58% of patients were infected with cagA positive H. pylori compared to 36% of controls (P = 0.002). Mean systemic levels of Hp-HSP-60 IgG were also higher in patients than in controls (27.9 vs 18.7, P = 0.0001). These antibody levels were also significantly higher in H. pylori positive patients (P = 0.0001). There was a strong correlation between Hp-HSP-60 antibody levels and occurrence of myocardial infarction (P = 0.003). CagA positive H. pylori infection may be associated with the development of CAD. High levels of Hp-HSP-60 antibodies may constitute a marker and/or concomitant pathogenic factor of the disease. Full article