Molecular-Based Identification of Actinomycetes Species That Synthesize Antibacterial Silver NanoparticlesRead the full article
International Journal of Microbiology publishes papers on microorganisms and their interaction with hosts and the environment. The journal covers all microbes, including bacteria, fungi, viruses, archaea, and protozoa.
Chief Editor, Professor Urakawa, is currently based at Florida Gulf Coast University as Professor of Marine and Ecological Sciences and has a background in Environmental Microbiology and Microbial Ecology.
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Molecular Typing of Klebsiella pneumoniae Clinical Isolates by Enterobacterial Repetitive Intergenic Consensus Polymerase Chain Reaction
Aim. Klebsiella pneumoniae is one of the most important causes of nosocomial infections, including pneumonia, sepsis, and urinary tract infection. Enterobacterial repetitive intergenic consensus polymerase chain reaction (ERIC-PCR) technique is a quick, reliable, and cost-effective method for molecular typing of Enterobacteriaceae family members. This study aimed to detect genetic relatedness among K. pneumoniae isolates from hospitals in Hamadan city, using ERIC-PCR technique. Materials and Methods. A total of 72 K. pneumoniae isolates were collected from patients admitted to Besat and Sina hospitals. After detection and confirmation of K. pneumonia isolates by chemical and conventional microbiological methods, DNAs were extracted after 24 hours of incubation at 37°C, using the boiling method. ERIC-PCR technique was carried out, and the ERIC patterns were analyzed by online data analysis service (inslico.ehu.es). ERIC profiles were compared using Dice method and clustered by UPGMA (unweighted pair group method with arithmetic mean) program. Also, the samples were evaluated by PCR method for the detection of aerobactin gene within their genome. Finding. The genetic relatedness among K. pneumoniae isolates was studied, and results established the genetic diversity of the clinical isolates by detecting 25 different ERIC types, including 14 common types and 11 unique types. Also, none of the isolates had aerobactin gene. Discussion. The results of this study showed high genetic diversity among K. pneumoniae strains, indicating the polyclonal distribution of K. pneumoniae isolates in Hamadan hospitals. This diversity causes problems for the treatment of infections due to the circulation of diverse K. pneumoniae clones, which possibly have different antimicrobial susceptibility patterns.
Prevalence of Intestinal Parasites and Gastrointestinal Carriage of Pathogenic Gram Negative Enteric Bacteria among Apparently Healthy Food Handlers of Public Hospitals, Addis Ababa, Ethiopia
Background. Foodborne diseases are major public health problems in developing countries like Ethiopia. Food handlers with poor personal hygiene working in hospitals could be infected with different intestinal parasites and pathogenic enteric bacteria. Therefore, they could pose a potential risk of foodborne infection to patients and the community. Methods. An institutional based cross-sectional study conducted from March to June 2017. Besides, sociodemographic data were collected using a structured questionnaire, freshly passed stool specimens for direct wet mount smear examination, and formalin ether concentration techniques performed for the detection of parasites. For bacterial identification culture, biochemical tests and antimicrobial sensitivity (Kirby-Baure disk diffusion method) have been performed. Finally, validated data were analyzed using statistical package for social science version 20 (SPSS). Results. From 368 food handlers who participated in the study, 81% were females. 119 (32.34%) were positive for at least one intestinal parasite. The most prevalent parasite was Entamoeba histolytica/dispar 48 (13%), followed by Giardia lamblia 36 (9.78%), Taenia Species 21 (5.7%), Ascaris lumbricoide 8 (2.2%), Trichuris trichiura 5 (1.4%), and Hook worm 1 (0.3%). Regarding the prevalence of enteric bacteria 17(4.6%), food handlers were positive for Salmonella 14 (3.8%) and Shigella flexneri 3 (0.8%). No E. coli O157 : H7 was isolated. All 100% (n = 14) Salmonella isolates were resistant to ampicillin (10 µg) and erythromycin (15 µg). Similarly, 100% (n = 3) of Shigella flexneri isolates were resistant to ampicillin (10 µg) and tetracycline (30 µg). 14.3% (n = 2) Salmonella and 66.7% (n = 2) Shigella flexneri isolates were MDR. Conclusion. The study showed significant carriage of pathogenic microorganisms among food handlers. Therefore, hospital administrators and other stake holders should put measures in place to break chain of transmission routes from silent carrier to other peoples particularly patients at hospital and the community at large.
Chemical Composition and Microbial Contaminants of Poha Beer: A Local Nonalcoholic Beverage in the Bolgatanga Municipality, Ghana
Microbial and physicochemical analysis was performed on randomly sampled Poha Beer manufactured and vended in the Bolgatanga Municipality, Ghana. Poha Beer as it is referred to in Dagbani, is a Tamarindus indica fruit extract, a local nonalcoholic beverage originally processed and sold by rural women of the Dagomba ethnic descend. Morphological examination of bacterial cultures, Gram staining, and biochemical confirmatory tests were used to detect the presence of microbial pathogens in 45 samples of Poha Beer. A refractometer, a flame photometer and an atomic absorption spectrometer were used for the elemental analysis. All Poha Beer samples obtained from the Bolgatanga Municipality were positive for yeast, E. coli, Enterobacter sp. and Bacillus cereus. Pb was not detected in any of the samples. Chemical components detected include Zn2+ (average, 0.154 mg/L), Cd2+ (0.056 mg/L), Na+ (1.723 mg/L), Ca2+ (2.262 mg/L) and K+ (3.96 mg/L). All samples were acidic with an average pH value of 3.55. The Brix value of samples, however, was between 9.0 and 11.4 % per 40 mL of Poha Beer. Therefore, Poha Beer processed and sold in the Bolgatanga Municipality is acidic and contains detrimental amounts of Cd2+ and bacterial pathogens which may render it unwholesome for human consumption.
The Role of T Helper 17 (Th17) and Regulatory T Cells (Treg) in the Pathogenesis of Vulvovaginal Candidiasis among HIV-Infected Women
Background. The study sought to describe relationships between 20 cytokines and chemokines (IL-1β, IL-2, IL-4, IL-5, IL-6, IL-7, IL-8, IL-10, IL-12, IL-13, IL-17, G-CSF, GM-CSF, IFN-γ, MCP-1, MIP-1β, TNF-α, TGF-β1, TGF-β2, and TGF-β3) and the presence of vulvovaginal candidiasis (VVC) in women, stratified by HIV status. Methods. Plasma and genital samples were obtained from 51 clinic attendees in KwaZulu-Natal between June 2011 and December 2011. Cytokine and chemokine concentrations were measured by Luminex® multiplex immunoassays. Multiple comparisons of means of cytokine/chemokine levels displaying significant differences in univariate analyses across the study groups were performed using post hoc Bonferroni pairwise tests considering a type I error rate of 0.05. A discriminant analysis (DA) was carried out to identify linear combinations of variates that would maximally discriminate group memberships. Results. Of the 51 participants, 16/26 HIV-infected and 15/25 HIV-uninfected women were diagnosed with VVC. DA identified 2 variables (MIP-1β and TGF-β3) in plasma (Box’s M (5.49), (0.57) > α (0.001); Wilks’ lambda = 0.116, ) and 1 variable (IL-13) in vaginal secretions (Box’s M (2.063), (0.37) > α (0.001); Wilks’ lambda = .677, ) as able to discriminate the HIV + VVC + group, whilst TGF-β1 in plasma discriminated the HIV + VVC − group. Mean concentrations of genital IL-6, IL-8, IL-10, IL-17, and TGF-β3 were significantly higher in HIV infected women coinfected with VVC. Conclusions. In HIV-infected women, VVC might be explained by a decline of Th17 cells, hence a decrease of Th17/Treg ratio.
Purification, Characterization, and Biocatalytic and Antibiofilm Activity of a Novel Dextranase from Talaromyces sp.
Dextranase is a useful enzyme that catalyzes the degradation of dextran to low-molecular-weight fractions, which have many critical commercial and clinical applications. Endophytic fungi represent a source of both high heat-stable and pH-stable enzymes. In this study, from Delonix regia bark by plate assay, out of 12 isolated fungal strains, hyaline zones were detected in only one strain. By using the standard ITS rDNA sequencing analysis, the isolated strain was identified as Talaromyces sp. In the case of carbon source, in a medium containing 1% dextran T2000 as the sole carbon source, the maximum dextranase activity reached approximately 120 U/ml after incubation of 2 days where the optimum pH was 7.4. Peptone addition to the production medium as a sole nitrogen source was accompanied by a significant increase in the dextranase production. Similarly, some metal ions, such as Fe2+ and Zn2+, increased significantly enzyme production. However, there was no significant difference resulting from the addition of Cu2+. The crude dextranase was purified by ammonium sulfate fractionation, followed by Sephadex G100 chromatography with 28-fold purification. The produced dextranase was 45 kDa with an optimum activity at 37°C and a pH of 7. Moreover, the presence of MgSO4, FeSO4, and NH4SO4 increased the purified dextranase activity; however, SDS and EDTA decreased it. Interestingly, the produced dextranase expressed remarkable pH stability, temperature stability, and biofilm inhibition activity, reducing old-established biofilm by 86% and biofilm formation by 6%.
Microbiological Assessment of the Different Hand Drying Methods and Washroom Environment Cross-Contamination
Proper hand drying is a fundamental part of the hand hygiene process looking at optimizing the elimination of potentially pathogenic microbes. This research compared the effectiveness of three different hand drying methods—paper towels, the use of warm air dryers in stationary hands position, and the use of air drying while hand rubbing—and their potential for cross-contamination of other users and the surrounding environment. One hundred sixty samples were collected from finger pads and palms, before and after drying. The outlet of the air dryers, air current emitted from the air dryers, and washroom environment air were also tested. The study reported that paper towels were more successful in eliminating bacteria and lead to less contamination to the washroom environment compared to the air dryers. The average number of bacteria obtained from volunteers using hand air dryer while hand rubbing was significantly higher than drying with air dryer while holding hands stationary. Plates exposed to the turned-off dryer for 5 minutes gave an average of only 25 colonies/plate, while plates exposed to the air outlet of the turned-on warm air dryers provided 292 colonies/plate. Placing Petri dishes at least one meter away from the dryer in the washroom for 30 minutes gave 72.5 colonies/plate. The current research also documented frequent contamination of public washroom environments and showed dissemination of potential pathogens, including Escherichia coli (E. coli), Klebsiella species, Bacillus cereus (B. cereus), Staphylococcus aureus (S. aureus), and coagulase-negative Staphylococci. Over 70.0% of Staphylococci were resistant to at least three antibiotics and 50.0% revealed coresistance to at least four antibiotics including penicillin, erythromycin, clindamycin, and co-trimoxazole. The method of hand drying may serve as a risk factor of cross-contamination from users to the environment and subsequent users and as reservoirs of drug-resistant bacteria in public washrooms.