As a bacterial culture medium, citrated sheep blood agar is a practical alternative to citrated human blood agar in laboratories of developing countries

Microbiological and molecular studies on a multidrug-resistant Pseudomonas aeruginosa from a liver transplant patient with urinary tract infection in Egypt

BACKGROUND

Pseudomonas aeruginosa is an opportunistic pathogen responsible for complicated UTIs and exhibits high antibiotic resistance, leading to increased mortality rates, especially in cases of multidrug-resistant strains. This study aimed to investigate the antibiotic susceptibility patterns and genomic characterization of XDR strains identified in end-stage liver disease patients who underwent liver transplants.

METHODS

In this study, a number of 30 individuals who underwent liver transplants were registered. Ninety urine and 60 wound site swab samples were collected and processed for culturing, identification, and antimicrobial sensitivity. Extensively drug-resistant strain EMARA01 was confirmed through Sanger sequencing and was then processed for whole genome sequencing to characterize the genomic pattern. Sequencing data were processed for de novo assembly using various tools and databases, including genome annotation, serotype identification, virulence factor genes, and antimicrobial resistance gene. Pangenome analysis of randomly selected 147 reference strains and EMAR01 sequenced strain was performed using the Bacterial Pan Genome Analysis (BPGA) software.

RESULTS

Of these total examined samples, nosocomial infection due to P. aeruginosa was detected in twelve patients' samples. AST analysis showed that P. aeruginosa strains exhibit resistance to tobramycin, erythromycin, and gentamicin, followed by piperacillin and ofloxacin, and no strains exhibit resistance to meropenem and imipenem. The CARD database identified 59 AMR genes similar to the EMAR01 strain genome and mostly belong to the family involved in the resistance-nodulation-cell division (RND) antibiotic efflux pump. Five genes; nalC, nalD, MexR, MexA, and MexB, exhibit resistance to 14 classes of antibiotics, while two AMR; CpxR, and OprM, exhibit resistance to 15 classes of drugs. Pangenome analysis revealed that the pan-genome remained open, suggesting the potential for acquiring accessory and unique genes. Notably, the genes predominantly involved in amino acid transport metabolism were identified using the KEGG database.

CONCLUSIONS

This study provides valuable insights into the antimicrobial resistance profile, genetic features, and genomic evolution of P. aeruginosa strains causing UTIs in liver transplant patients. The findings emphasize the significance of comprehending AMR mechanisms and genetic diversity in P. aeruginosa for developing effective treatment strategies and infection control measures.

Evaluation of the feasibility for replacing sheep blood with human blood in culture media used in microbiological diagnostics

The present study aimed to suggest the replacement of animal blood with human blood in culture media, involving alternative methods and ethical considerations, such as animal welfare, in addition to potential laboratory cost reduction. Characteristics of growth and hemolysis development were compared in different culture media, using both sheep blood and human blood. Blood types from the ABO blood group system were tested, and commercially acquired sheep blood agar was used for comparison. Bacteria of the genus Streptococcus spp., Staphylococcus aureus, Enterococcus faecalis, and Escherichia coli were tested. It was observed that growth in media with type A and O positive blood showed closer similarities to those performed in agar with sheep blood. Depending on the bacterial species, the results were either more positive or not, with faster-growing and less demanding bacteria showing better results than, for example, S. pneumoniae, which demonstrated difficulty in the growth process and hemolysis generation in human blood agar. The research suggests that in some situations, sheep blood could be replaced, especially when the goal is growth and isolation, but may not be as suitable when the objective is to analyze hemolysis or when the studied species is demanding.

Microbial Adhesion to Different Thermoplastic Denture Base Materials in Kennedy Class I Partially Edentulous Patients

Introduction Since the polished and fitting surface of the denture base may promote the colonization of microorganisms, it is essential to know how the different types of denture bases prevent or encourage the adhesion of microorganisms. This study aimed to compare the microbial adhesion to the polished and fitting surfaces of thermoplastic nylon, thermoplastic acetal, and thermoplastic acrylic denture bases in Kennedy Class Ⅰ, partially edentulous patients. Materials and methods Thirteen patients were included in the study. The group consisted of eight males (61.54%) and five females (38.46%), with an age range of 41-50 years (mean age 46.1 years). Three types (groups) of removable partial dentures will be made for each patient using different thermoplastic denture base materials: thermoplastic nylon; thermoplastic acetal; and thermoplastic acrylic. The polished and fitting surfaces of the denture bases were swabbed after a one-month follow-up period. Microbial adhesion was evaluated by counting the microorganisms' colony-forming units (CFU) in the collected specimens. The data were collected and statistically analyzed. Results The study revealed no statistically significant difference in microbial adhesion to both polished and fitting surfaces between all types of studied thermoplastic denture base materials. However, the results showed that for the polished surface, the microbial adhesion median of thermoplastic acrylic denture base (40.5 CC x 102/ml) was higher than that of thermoplastic acetal (29.0 CC x 102/ml) and thermoplastic nylon (16.0 CC x 102/ml). Regarding the fitting surface, the microbial adhesion median of thermoplastic acrylic (51.0 CC x 102/ml) is higher than that of thermoplastic acetal (41.0 CC x 102/ml) and thermoplastic nylon (23.0 CC x 102/ml). Conclusion The thermoplastic nylon denture base materials showed less microbial adhesion among the studied thermoplastic materials, so it may be recommended to be used as a denture base material for individuals at high risk of denture stomatitis.

Use of Blood Powder (Ground and Irradiated) for the Manufacture of Chocolate Agar

Chocolate agar (CA) is an enriched medium for the isolation and identification of fastidious bacteria. Defibrinated blood is used to manufacture CA, but this expensive product is not always affordable for companies in developing countries. Blood powder (BP) is potentially a cheaper alternative, although its pre-treatment using autoclaving can impair the quality of the media. Therefore, optimization of BP as a substitute for defibrinated blood for CA manufacture deserves further research. CA was manufactured with irradiated BP (dehydrated bovine blood powder) and its physical and microbiological characteristics were compared with those of conventional CA and CA prepared with autoclaved BP. Each medium was seeded with 20-200 CFU of target bacteria using the spiral pouring method. Finally, another medium was prepared using BP pre-treated by grinding and gamma irradiation and its performance assessed. Compared to conventional CA, the medium containing ground and irradiated BP provided a similar CFU count for both fastidious (Neisseria, Haemophilus, Campylobacter, and Streptococcus) and non-fastidious (Moraxella, Staphylococcus, Enterococcus, Klebsiella, and Pseudomonas) species, unlike the medium prepared with BP subjected only to irradiation, which provided a lower growth of fastidious species. Morphology and characteristics of all bacterial colonies were very similar in conventional CA and the new medium, the number of Pseudomonas CFU being higher in the latter. The medium prepared with ground plus irradiated vs. irradiated BP more closely resembled conventional CA, having a browner background. The new CA medium prepared with ground and gamma irradiation-sterilized BP has comparable productivity properties to conventional CA. Therefore, it could be a more practical and economical methodology to facilitate large-scale CA manufacture.

Low Mortality among Under-5 Children with Severe Community-Acquired Pneumonia: A 5-Year Retrospective Analysis of 588 Admissions in Ibadan, Nigeria

Objective Community-acquired pneumonia (CAP) is the commonest cause of death in under-5 children worldwide. Although the mortality from CAP has decreased over the last decade, it is still unacceptably high in lower-middle-income countries (LMICs). We aimed to determine the case fatality rate (CFR), and factors associated with treatment failure and outcome, using recommended antimicrobials.

Methods A 5-year retrospective review of severe pediatric pneumonia admissions between August 1st, 2014 and July 31st, 2019 at the University College Hospital, Ibadan, Nigeria was conducted. Relevant clinical information including antibiotics use and outcome was analyzed using descriptive statistics, test of association, and logistic regression.

Results There were 588 children aged 2 to 59 months, male:female ratio was 1.5:1. About two-thirds were aged ≤12 months. The majority were fully immunized for age (87.2%), about 34% were malnourished and 68% were hypoxemic at presentation. Only 71% of children were commenced on the recommended first-line antibiotics following the Pediatric Association of Nigeria (PAN) antibiotic guidelines. Initial antibiotics were changed in 22.3% of the patients. The need to change intravenous (iv) amoxicillin plus iv gentamicin was necessary in 23.80% compared with 18.1% for iv cefuroxime plus iv gentamicin. Severe acute malnutrition (odds ratio [OR]: 2.8 [95% confidence interval [CI]: 1.1–7.3]) and hypoxemia (OR:2.3 [95%CI: 1.0–5.6]) were independently associated with antibiotics change. The CFR was 1.36%.

Conclusion The low CFR suggests a better outcome compared with other previous studies in LMICs. However, the high rate of antibiotics changes (22.3%) was possibly due to failure of first line antibiotics; especially among malnourished and hypoxemic children. Randomized controlled trial of iv cefuroxime plus gentamicin versus iv amoxicillin plus gentamicin is recommended.

Molecular study of Enterobacteriaceae bacterium isolated from dishwashers

The Enterobacteriaceae family is considered one of the medically essential families in which there is a continuous change in classification, and new species are added to it. In this study, we obtained a novel strain registered in the NCBI under Enterobacteriaceae bacterium strain PRL 4-2, with the accession number MW540823, and the isolate considered unclassified Enterobacteriaceae. The isolate was obtained from dishwashers, which is a mine for many new species and strains due to the unique environmental conditions of this habitat, fluctuation in temperature, use of high temperatures, utilization of cleaning materials as well as humidity and the presence of organic materials, especially in case of neglect of cleaning. The isolate was characterized by its slow growth on culture media and its ability to form biofilms and possess some virulence factors. Its resistance to antibiotics was also studied, as it showed resistance to the antibiotics used in this study. The oddness for this strain is that it showed a different diagnosis when using VITEK (The VITEK 2 system has everything healthcare laboratories need for fast, accurate microbial identification and antibiotic susceptibility testing.) compared to diagnosis using 16S rRNA. As for the taxonomic tree, the closest species was Enterobacter sp. Strain 188. This study supplements a few other studies of this novel species, isolated from different environments. These researches can be integrated to give an itinerary for other studies on the new species and their different capabilities. Keywords. Enterobacteriaceae bacterium, dishwasher, Enterobacteriaceae bacterium PRL-2, Enterobacter sp., biofilm.

Prevalence of Bacterial Burden on Macroscopic Contaminants of Orthopaedic Surgical Instruments Following Sterilization

BACKGROUND

Macroscopic contamination of orthopaedic instruments with particulates, including cortical bone and polymethyl methacrylate (PMMA) cement, having previously undergone preoperative sterilization, is frequently encountered peri- or intraoperatively, calling into question the sterility of such instruments.

AIM

The purpose of this study is to determine if macroscopic contaminants of orthopaedic surgical instrumentation maintain a bacterial burden following sterile processing. Additionally, this manuscript looks to determine the most commonly contaminated instruments and what the most common contaminants are.

METHODS

At a single tertiary referral centre, we prospectively collected available macroscopic contaminants in orthopaedic instrument trays over a six month period from August 2021 to May 2022. When identified, these specimens were swabbed and plated on sheep blood agar. All specimens were incubated at 37°C for 14 days, and visually inspected for colony formation. When bacterial colony formation was identified, samples were sent for species identification.

RESULTS

A total of 33 contaminants were tested, with only one contaminant growing bacterial colonies which was found to be Corynebacterium. The items most commonly found to have macroscopic contamination were surgical trays (9) and cannulated drills. The identifiable contaminants were bone (10), PMMA bone cement (4), and hair (4). There were 11 macroscopic contaminants that were not identifiable.

CONCLUSION

This study found that 97% of macroscopic orthopaedic surgical instrument contaminants that underwent sterile processing did not possess a bacterial burden. Contaminants discovered during a procedure are likely to be sterile and do not pose a substantially increased risk of infection to a patient.

Genetic background of Cambodian pneumococcal carriage isolates following pneumococcal conjugate vaccine 13

Streptococcus pneumoniae (the pneumococcus) is a leading cause of childhood mortality globally and in Cambodia. It is commensal in the human nasopharynx, occasionally resulting in invasive disease. Monitoring population genetic shifts, characterized by lineage and serotype expansions, as well as antimicrobial-resistance (AMR) patterns is crucial for assessing and predicting the impact of vaccination campaigns. We sought to elucidate the genetic background (global pneumococcal sequence clusters; GPSCs) of pneumococci carried by Cambodian children following perturbation by pneumococcal conjugate vaccine (PCV) 13. We sequenced pre-PCV13 (01/2013-12/2015, N=258) and post-PCV13 carriage isolates (01/2016-02/2017, N=428) and used PopPUNK and SeroBA to determine lineage prevalence and serotype composition. Following PCV13 implementation in Cambodia, we saw expansions of non-vaccine type (NVT) serotypes 23A (GPSC626), 34 (GPSC45) and 6D (GPSC16). We predicted antimicrobial susceptibility using the CDC-AMR pipeline and determined concordance with phenotypic data. The CDC-AMR pipeline had >90 % concordance with the phenotypic antimicrobial-susceptibility testing. We detected a high prevalence of AMR in both expanding non-vaccine serotypes and residual vaccine serotype 6B. Persistently high levels of AMR, specifically persisting multidrug-resistant lineages, warrant concern. The implementation of PCV13 in Cambodia has resulted in NVT serotype expansion reflected in the carriage population and driven by specific genetic backgrounds. Continued monitoring of these GPSCs during the ongoing collection of additional carriage isolates in this population is necessary.

Considerations in evaluating equipment-free blood culture bottles: A short protocol for use in low-resource settings

Use of equipment-free, “manual” blood cultures is still widespread in low-resource settings, as requirements for implementation of automated systems are often not met. Quality of manual blood culture bottles currently on the market, however, is usually unknown. An acceptable quality in terms of yield and speed of growth can be ensured by evaluating the bottles using simulated blood cultures. In these experiments, bottles from different systems are inoculated in parallel with blood and a known quantity of bacteria. Based on literature review and personal experiences, we propose a short and practical protocol for an efficient evaluation of manual blood culture bottles, aimed at research or reference laboratories in low-resource settings. Recommendations include: (1) practical equivalence of horse blood and human blood; (2) a diverse selection of 10 to 20 micro-organisms to be tested (both slow- and fast-growing reference organisms); (3) evaluation of both adult and pediatric bottle formulations and blood volumes; (4) a minimum sample size of 120 bottles per bottle type; (5) a formal assessment of usability. Different testing scenarios for increasing levels of reliability are provided, along with practical tools such as worksheets and surveys that can be used by laboratories wishing to evaluate manual blood culture bottles.

Preservation of Streptococcus pneumoniae quality control strains using chocolate agar blocks in glycerol at minus 70 degrees celsius

We present a method for storage of the quality control strain of S. pneumoniae that could be used in low resource settings. Small blocks of chocolate agar with growth were placed in glycerol (60%V/V) and stored at minus 70 °C. Viability and cultural characteristics were maintained for the testing period of 10 months. The wide availability of both chocolate agar and glycerol make this a suitable alternative to other specialized formulations usually used to maintain stocks of S. pneumoniae ATCC 49619 strain required for quality control of susceptibility testing.

Detection of food fraud of meat products from the different brands by application of histological methods

In Sohag City, 400 samples were collected from different food markets of different meat products from two companies with high and low prices (e.g., minced meat, kofta sausage, beef burger, and luncheon meat) for determining food fraud. Light, fluorescence, and scanning electron microscopy (SEM) were used to examine the samples. "Special histochemical stains" permit the microscopic examination of different cell types, structures, and/or microorganisms. Histological examination revealed variant tissue types, besides skeletal muscles. Nuchal ligaments, bones, hyaline cartilages, white fibrocartilages, large and medium arteries, cardiac muscles, tendons, and collagenous connective tissues comprised the capsule of a parenchymatous organ. Additionally, a crystal of food additives was recognized using light microscopy and SEM. SEM allows the visualization of bacterial contamination. Using different microscopic anatomy techniques is an efficient methodology for qualitative evaluations of various meat products. No difference in quality was observed between low- and high-priced meat products.

The impact of 10-valent pneumococcal vaccine introduction on invasive disease in Fiji

BACKGROUND

In 2012, Fiji introduced the 10-valent pneumococcal conjugate vaccine (PCV10). We assessed the impact of PCV10 on invasive pneumococcal disease (IPD), probable bacterial or pneumococcal meningitis (PBPM), meningitis and sepsis 3-5 years post-introduction.

METHODS

Laboratory-confirmed IPD and PBPM cases were extracted from national laboratory records. ICD-10-AM coded all-cause meningitis and sepsis cases were extracted from national hospitalisation records. Incidence rate ratios were used to compare outcomes pre/post-PCV10, stratified by age groups: 1-23m, 2-4y, 5-9y, 10-19y, 20-54y, ≥55y. To account for different detection and serotyping methods in the pre-and post-PCV10 period, a Bayesian inference model estimated serotype-specific changes in IPD, using pneumococcal carriage and surveillance data.

FINDINGS

There were 423 IPD, 1,029 PBPM, 1,391 all-cause meningitis and 7,611 all-cause sepsis cases. Five years post-PCV10 introduction, IPD declined by 60% (95%CI: 37%, 76%) in children 1-23m months old, and in age groups 2-4y, 5-9y, 10-19y although confidence intervals spanned zero. PBPM declined by 36% (95%CI: 21%, 48%) among children 1-23 months old, and in all other age groups, although some confidence intervals spanned zero. Among children <5y of age, PCV10-type IPD declined by 83% (95%CI; 70%, 90%) and with no evidence of change in non-PCV10-type IPD (9%, 95%CI; -69, 43%). There was no change in all-cause meningitis or sepsis. Post-PCV10, the most common serotypes in vaccine age-eligible and non-age eligible people were serotypes 8 and 23B, and 3 and 7F, respectively.

INTERPRETATIONS

Our study demonstrates the effectiveness of PCV10 against IPD in a country in the Asia-Pacific of which there is a paucity of data.

FUNDING

This study was support by the Department of Foreign Affairs and Trade of the Australian Government and Fiji Health Sector Support Program (FHSSP). FHSSP is implemented by Abt JTA on behalf of the Australian Government.

Differential Root Exudation and Architecture for Improved Growth of Wheat Mediated by Phosphate Solubilizing Bacteria

Phosphorous (P) deficiency is a major challenge faced by global agriculture. Phosphate-solubilizing bacteria (PSB) provide a sustainable approach to supply available phosphates to plants with improved crop productivity through synergistic interaction with plant roots. The present study demonstrates an insight into this synergistic P-solubilizing mechanism of PSB isolated from rhizosphere soils of major wheat-growing agro-ecological zones of Pakistan. Seven isolates were the efficient P solubilizers based on in vitro P-solubilizing activity (233-365 μg ml-1) with a concomitant decrease in pH (up to 3.5) by the production of organic acids, predominantly acetic acid (∼182 μg ml-1) and gluconic acid (∼117 μg ml-1). Amplification and phylogenetic analysis of gcd, pqqE, and phy genes of Enterobacter sp. ZW32, Ochrobactrum sp. SSR, and Pantoea sp. S1 showed the potential of these PSB to release orthophosphate from recalcitrant forms of phosphorus. Principal component analysis indicates the inoculation response of PSB consortia on the differential composition of root exudation (amino acids, sugars, and organic acids) with subsequently modified root architecture of three wheat varieties grown hydroponically. Rhizoscanning showed a significant increase in root parameters, i.e., root tips, diameter, and surface area of PSB-inoculated plants as compared to uninoculated controls. Efficiency of PSB consortia was validated by significant increase in plant P and oxidative stress management under P-deficient conditions. Reactive oxygen species (ROS)-induced oxidative damages mainly indicated by elevated levels of malondialdehyde (MDA) and H2O2 contents were significantly reduced in inoculated plants by the production of antioxidant enzymes, i.e., superoxide dismutase, catalase, and peroxidase. Furthermore, the inoculation response of these PSB on respective wheat varieties grown in native soils under greenhouse conditions was positively correlated with improved plant growth and soil P contents. Additionally, grain yield (8%) and seed P (14%) were significantly increased in inoculated wheat plants with 20% reduced application of diammonium phosphate (DAP) fertilizer under net house conditions. Thus, PSB capable of such synergistic strategies can confer P biofortification in wheat by modulating root morphophysiology and root exudation and can alleviate oxidative stress under P deficit conditions.

Staquorsin: A Novel Staphylococcus aureus Agr-Mediated Quorum Sensing Inhibitor Impairing Virulence in vivo Without Notable Resistance Development

The emergence of microbial resistance to the available antibiotics is a major public health concern, especially with the limited rate of developing new antibiotics. The utilization of anti-virulence agents is a non-conventional approach that can be used to combat microbial infection. In Staphylococcus aureus, many virulence factors are regulated by the Agr-mediated quorum sensing (QS). We developed a chemical compound that acts a potential Agr-inhibitor without reducing bacterial viability. The compound was designated staquorsin for Staphylococcus aureus QS inhibitor. In silico analyses confirmed the binding of staquorsin to the AgrA active site with an absolute binding score comparable to savirin, a previously described AgrA inhibitor. However, staquorsin turned out to be superior over savarin in not affecting the S. aureus viability in concentrations up to 600 μM. On the other hand, savirin inhibited S. aureus growth in concentrations as low as 25 μM. Moreover, staquorsin proved to be a potent inhibitor of the Agr system by inhibiting hemolysins, lipase production, and affecting biofilms formation and detachment. On the molecular level it significantly inhibited the effector transcript RNA III. In vivo testing, using the murine skin abscess model, confirmed the ability of staquorsin to modulate S. aureus virulence by effectively controlling the infection. Twenty passages of S. aureus in the presence of 40 μM staquorsin have not resulted in loss of activity as evidenced by maintaining its ability to reduce hemolysin production and RNA III transcript levels. In conclusion, we hereby describe a novel anti-virulence compound inhibiting the S. aureus Agr-system and its associated virulence factors. It is active both in vitro and in vivo, and its frequent use does not lead to the development of resistance. These findings model staquorsin as a promising drug candidate to join the fierce battle against the formidable pathogen S. aureus.

Culture media for clinical bacteriology in low- and middle-income countries: challenges, best practices for preparation and recommendations for improved access

BACKGROUND

Culture media are fundamental in clinical microbiology. In laboratories in low- and middle-income countries (LMICs), they are mostly prepared in-house, which is challenging.

OBJECTIVES

This narrative review describes challenges related to culture media in LMICs, compiles best practices for in-house media preparation, gives recommendations to improve access to quality-assured culture media products in LMICs and formulates outstanding questions for further research.

SOURCES

Scientific literature was searched using PubMed and predefined MeSH terms. In addition, grey literature was screened, including manufacturer's websites and manuals as well as microbiology textbooks.

CONTENT

Bacteriology laboratories in LMICs often face challenges at multiple levels: lack of clean water and uninterrupted power supply, high environmental temperatures and humidity, dust, inexperienced and poorly trained staff, and a variable supply of consumables (often of poor quality). To deal with this at a base level, one should be very careful in selecting culture media. It is recommended to look for products supported by the national reference laboratory that are being distributed by an in-country supplier. Correct storage is key, as is appropriate preparation and waste management. Centralized media acquisition has been advocated for LMICs, a role that can be taken up by the national reference laboratories, next to guidance and support of the local laboratories. In addition, there is an important role in tropicalization and customization of culture media formulations for private in vitro diagnostic manufacturers, who are often still unfamiliar with the LMIC market and the plethora of bacteriology products.

IMPLICATION

The present narrative review will assist clinical microbiology laboratories in LMICs to establish best practices for handling culture media by defining quality, regulatory and research paths.

Evaluation of MicroScan Bacterial Identification Panels for Low-Resource Settings

Bacterial identification is challenging in low-resource settings (LRS). We evaluated the MicroScan identification panels (Beckman Coulter, Brea, CA, USA) as part of Médecins Sans Frontières' Mini-lab Project. The MicroScan Dried Overnight Positive ID Type 3 (PID3) panels for Gram-positive organisms and Dried Overnight Negative ID Type 2 (NID2) panels for Gram-negative organisms were assessed with 367 clinical isolates from LRS. Robustness was studied by inoculating Gram-negative species on the Gram-positive panel and vice versa. The ease of use of the panels and readability of the instructions for use (IFU) were evaluated. Of species represented in the MicroScan database, 94.6% (185/195) of Gram-negative and 85.9% (110/128) of Gram-positive isolates were correctly identified up to species level. Of species not represented in the database (e.g., Streptococcus suis and Bacillus spp.), 53.1% out of 49 isolates were incorrectly identified as non-related bacterial species. Testing of Gram-positive isolates on Gram-negative panels and vice versa (n = 144) resulted in incorrect identifications for 38.2% of tested isolates. The readability level of the IFU was considered too high for LRS. Inoculation of the panels was favorably evaluated, whereas the visual reading of the panels was considered error-prone. In conclusion, the accuracy of the MicroScan identification panels was excellent for Gram-negative species and good for Gram-positive species. Improvements in stability, robustness, and ease of use have been identified to assure adaptation to LRS constraints.

Genome sequencing and analysis of plant growth-promoting attributes from Leclercia adecarboxylata

Plant growth-promoting bacteria are ecological alternatives for fertilization, mainly for gramineous. Since plant x bacteria interaction is genotype and strain dependent, searching for new strains may contribute to the development of new biofertilizers. We aim to characterize plant growth-promoting capacity of Leclercia adecarboxylata strain Palotina, formerly isolated by our group in corn. A single isolated colony was taken and its genome was sequenced using Illumina technology. The whole genome was compared to other Leclercia adecarboxylata strains, and their biological and growth-promoting traits, such as P solubilization and auxin production, were tested. Following that, a 4.8 Mb genome of L. adecarboxylata strain Palotina was assembled and the functional annotation was carried out. This paper is the first to report the genes associated with plant growth promotion demonstrating in vitro indole acid production by this strain. These results project the endophyte as a potential biofertilizer for further commercial exploitation.

Seed biopriming with P- and K-solubilizing Enterobacter hormaechei sp. improves the early vegetative growth and the P and K uptake of okra (Abelmoschus esculentus) seedling

Limited information is available that seed biopriming with plant growth-promoting Enterobacter spp. play a prominent role to enhance vegetative growth of plants. Contrary to Enterobacter cloacae, Enterobacter hormaechei is a less-studied counterpart despite its vast potential in plant growth-promotion mainly through the inorganic phosphorus (P) and potassium (K) solubilization abilities. To this end, 18 locally isolated bacterial pure cultures were screened and three strains showed high P- and K-solubilizing capabilities. Light microscopy, biochemical tests and 16S rRNA gene sequencing revealed that strains 15a1 and 40a were closely related to Enterobacter hormaechei while strain 38 was closely related to Enterobacter cloacae (Accession number: MN294583; MN294585; MN294584). All Enterobacter spp. shared common plant growth-promoting traits, namely nitrogen (N₂) fixation, indole-3-acetic acid production and siderophore production. The strains 38 and 40a were able to produce gibberellic acid, while only strain 38 was able to secrete exopolysaccharide on agar. Under in vitro germination assay of okra (Abelmoschus esculentus) seeds, Enterobacter spp. significantly improved overall germination parameters and vigor index (19.6%) of seedlings. The efficacy of root colonization of Enterobacter spp. on the pre-treated seedling root tips was confirmed using Scanning Electron Microscopy (SEM). The pot experiment of bioprimed seeds of okra seedling showed significant improvement of the plant growth (> 28%) which corresponded to the increase of P and K uptakes (> 89%) as compared to the uninoculated control plants. The leaf surface area and the SPAD chlorophyll index of bioprimed plants were increased by up to 29% and 9% respectively. This report revealed that the under-explored species of P- and K-solubilizing Enterobacter hormaechei sp. with multiple plant beneficial traits presents a great potential sustainable approach for enhancement of soil fertility and P and K uptakes of plants.

Seed biopriming with P- and K-solubilizing Enterobacter hormaechei sp. improves the early vegetative growth and the P and K uptake of okra (Abelmoschus esculentus) seedling

Limited information is available that seed biopriming with plant growth-promoting Enterobacter spp. play a prominent role to enhance vegetative growth of plants. Contrary to Enterobacter cloacae, Enterobacter hormaechei is a less-studied counterpart despite its vast potential in plant growth-promotion mainly through the inorganic phosphorus (P) and potassium (K) solubilization abilities. To this end, 18 locally isolated bacterial pure cultures were screened and three strains showed high P- and K-solubilizing capabilities. Light microscopy, biochemical tests and 16S rRNA gene sequencing revealed that strains 15a1 and 40a were closely related to Enterobacter hormaechei while strain 38 was closely related to Enterobacter cloacae (Accession number: MN294583; MN294585; MN294584). All Enterobacter spp. shared common plant growth-promoting traits, namely nitrogen (N2) fixation, indole-3-acetic acid production and siderophore production. The strains 38 and 40a were able to produce gibberellic acid, while only strain 38 was able to secrete exopolysaccharide on agar. Under in vitro germination assay of okra (Abelmoschus esculentus) seeds, Enterobacter spp. significantly improved overall germination parameters and vigor index (19.6%) of seedlings. The efficacy of root colonization of Enterobacter spp. on the pre-treated seedling root tips was confirmed using Scanning Electron Microscopy (SEM). The pot experiment of bioprimed seeds of okra seedling showed significant improvement of the plant growth (> 28%) which corresponded to the increase of P and K uptakes (> 89%) as compared to the uninoculated control plants. The leaf surface area and the SPAD chlorophyll index of bioprimed plants were increased by up to 29% and 9% respectively. This report revealed that the under-explored species of P- and K-solubilizing Enterobacter hormaechei sp. with multiple plant beneficial traits presents a great potential sustainable approach for enhancement of soil fertility and P and K uptakes of plants.

Buffalo dung-inhabiting bacteria enhance the nutrient enrichment of soil and proximate contents of Foeniculum vulgare Mill

The present study was aimed to study the effect of bacteria inhabiting in buffalo dung on nutritional properties of soil and plant. Three beneficial bacteria Proteus mirabilis, Pseudomonas aeruginosa, and Enterobacter xiangfangensis were isolated from buffalo dung to evaluate for their effects individually as well as in consortium. The combined effect of P. mirabilis and P. aeruginosa showed a significant enhancement in different biological parameters of Foeniculum vulgare such as primary branch (99.32%), secondary branch (98.32%), number of umbels (87.62%), number of umbellets (99.85%), number of seeds (104.94%), grain yield (62.38%), biological yield (35.99%), and harvest index (19.48%). Consortium of these potent bacteria also enhanced proximate constituents such as total ash (49.79%), ether extract (63.06%), crude fibre (48.91%), moisture content (33.40%), dry matter (31.45%), acid insoluble ash (33.20%), and crude protein (40.73%). A highly significant correlation (p ≤ 0.01) was found between nitrogen (r = 0.97), phosphorous (r = 0.95), and potassium (r = 0.97) contents of soil. This research enhances the knowledge of the effect of plant growth-promoting bacteria on nutrient properties of soil and fennel which deliver a new index for healthier use in organic agricultural practices.

Isolation and Characterization of a New Endophytic Actinobacterium Streptomyces californicus Strain ADR1 as a Promising Source of Anti-Bacterial, Anti-Biofilm and Antioxidant Metabolites

In view of the fast depleting armamentarium of drugs against significant pathogens, like methicillin-resistant Staphylococcus aureus (MRSA) and others due to rapidly emerging drug-resistance, the discovery and development of new drugs need urgent action. In this endeavor, a new strain of endophytic actinobacterium was isolated from the plant Datura metel, which produced secondary metabolites with potent anti-infective activities. The isolate was identified as Streptomyces californicus strain ADR1 based on 16S rRNA gene sequence analysis. Metabolites produced by the isolate had been investigated for their antibacterial attributes against important pathogens: S. aureus, MRSA, S. epidermis, Enterococcus faecium and E. faecalis. Minimum inhibitory concentration (MIC₉₀) values against these pathogens varied from 0.23 ± 0.01 to 5.68 ± 0.20 μg/mL. The metabolites inhibited biofilm formation by the strains of S. aureus and MRSA (Biofilm inhibitory concentration [BIC₉₀] values: 0.74 ± 0.08–4.92 ± 0.49 μg/mL). The BIC₉₀ values increased in the case of pre-formed biofilms. Additionally, the metabolites possessed good antioxidant properties, with an inhibitory concentration (IC₉₀) value of 217.24 ± 6.77 µg/mL for 1, 1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging. An insight into different classes of compounds produced by the strain ADR1 was obtained by chemical profiling and GC-MS analysis, wherein several therapeutic classes, for example, alkaloids, phenolics, terpenes, terpenoids and glycosides, were discovered.

Zinc solubilizing bacteria (Bacillus megaterium) with multifarious plant growth promoting activities alleviates growth in Capsicum annuum L

The present study was designed to isolate an array of zinc solubilizing bacteria (ZSB) and to characterize them for plant growth promotion (PGP) attributes with respect to Capsicum annuum L. For this purpose, seventy bacteria were procured from cow dung and screened for zinc solubilization (ZnO and ZnCO₃). Where, isolate CDK25 was found to be the most potent owing to its maximum zinc solubilization (ZnO) ability (5.0 cm). For quantitative assay, atomic absorption spectroscopy (AAS) was used, where CDK25 showed markedly higher solubilization of ZnO (20.33 ppm). It was investigated that CDK25 also endowed with multiple PGP attributes viz., Phosphate solubilization, Phytase production, Indole acetic acid (IAA) and Siderophore production. Quantitative study revealed isolate CDK25 to solubilize and produce maximum quantity of phosphate (281.59 μg/ml) and IAA (13.8 μg/ml) respectively. ZSB was applied in different treatments under pot culture assay, where T3 (seeds + CDK25) showed significant impact on plant growth parameters, besides showing maximum zinc content in fruit (0.25 mg/100 g). Hence, isolate CDK25 expresses highest potential throughout the experiments; as zinc solubilizer, PGP strain, and based on 16S rRNA gene sequencing identified as Bacillus megaterium. Therefore, meticulous use of this bacterium could aid in providing adequate amount of soluble zinc along with enhanced plants growth, nutrient uptake and yield in sustainable manner.

Evaluation of the total adenylate (ATP + ADP + AMP) test for cleaning verification in healthcare settings

Introduction

Evaluation of cleaning methods is the first step in the prevention of healthcare-associated infections. ATP hygiene monitoring tests are widely used for assessing the effectiveness of cleaning procedures. The test is easy to use and gives immediate results, however, ATP can be metabolized and degraded to ADP and AMP. Recently, a total adenylate [ATP + ADP + AMP(A3)] monitoring test has been developed. Our objective was to evaluate the usefulness of the A3 test for cleaning verification in healthcare settings.

Methods

The detection sensitivities of the ATP and the A3 tests were compared using blood, and debris derived from gloved-hand method and endoscopes immediately after endoscopic examination. The performance of the A3 test in monitoring cleanliness of high touch surfaces in the hospital and endoscopes at each cleaning step was also evaluated.

Results

For the hemolysate, the measurement values of the A3 test were stable, although ATP was promptly degraded. In debris from hands, the amount of A3 was 20 times higher than that of ATP. The detection sensitivities of the A3 test on residues derived from gastroscopes and colonoscopes were 3 and 8 times higher, respectively, than those from the ATP test. A field study indicated that a large number of microorganisms tend to show high A3 values on high touch surfaces in the hospital and on endoscopes.

Conclusions

The A3 test showed higher detection sensitivities than the conventional ATP test for organic debris associated with healthcare settings.

Optimal Conditions for Streptococcus pneumoniae Culture: In Solid and Liquid Media

Control of Streptococcus pneumoniae is mainly achieved by the use of existing vaccines. Capsular polysaccharides are the major antigenic component and are also the main virulence factor.Capsular polysaccharides must fulfill requirements of purity, uniformity, and an accurate molecular weight to be used as vaccine antigens. Vaccine production largely relies on cultivation of the pathogen in appropriate conditions.Here we describe widely used techniques to culture S. pneumoniae based on solid or complex liquid media, which are successfully applied in the diagnosis of the pathogen and in development and production of S. pneumoniae vaccines. Furthermore, we present a new chemically defined medium that can be used at lab scale.

Phosphate solubilizing bacteria with glucose dehydrogenase gene for phosphorus uptake and beneficial effects on wheat

The aim of this study was to isolate, characterize and use phosphate solubilizing bacteria to enhance the bioavailability of insoluble Ca-phosphate for wheat plants. For this purpose, 15 phosphorus solubilizing bacteria (PSB) were isolated from wheat rhizospheric soils of Peshawar and southern Punjab region, Pakistan. These isolates were identified using light microscopy and 16S rRNA gene. Among the isolated bacteria, two strains (Pseudomonas sp. MS16 and Enterobacter sp. MS32) were the efficient P solubilizers based on their P solubilization activity determined qualitatively (solubilization index 3.2-5.8) as well as quantitatively (136-280 μg mL-1). These two strains produced indole-3-acetic acid (25.6-28.1 μg mL-1), gibberellic acid (2.5-11.8), solubilized zinc compounds (SI 2.8-3.3) and showed nitrogenase and 1-Aminocyclopropane-1-carboxylic acid deaminase activity in vitro. Phosphate solubilization activity of Pseudomonas sp. MS16 was further validated by amplification, sequencing and phylogenetic analysis of glucose dehydrogenase (gcd) gene (LT908484) responsible for P solubilization. Response Surface Methodology for large-scale production was used to find optimal conditions (Temperature 22.5°C, pH 7) for P solubilization. Glucose was found to support higher P solubilization in vitro. In an in vitro experiment, PSB treated wheat seedlings improved germination and seedling vigor (11% increases) as compared to un-inoculated control. Rhizoscanning of these seedlings showed an increase in various root growth parameters. Wheat inoculation with selected strain MS16 showed pronounced effect on grain yield in pot (38.5% increase) and field (17-18% increase) experiments compared to non-inoculated control. Root colonization by PSB through Florescent in situ Hybridization and Confocal Laser Scanning Microscopy confirmed their rhizosphere competence in soil. BOX-PCR confirmed the re-isolated colonies of Pseudomonas sp. MS16. The results indicated that gluconic acid producing Pseudomonas sp. MS16 from un-explored soils may be cost effective and environment friendly candidate to improve plant growth and phosphorous uptake by wheat plants.

Microbial Degradation of Forensic Samples of Biological Origin: Potential Threat to Human DNA Typing

Forensic biology is a sub-discipline of biological science with an amalgam of other branches of science used in the criminal justice system. Any nucleated cell/tissue harbouring DNA, either live or dead, can be used as forensic exhibits, a source of investigation through DNA typing. These biological materials of human origin are rich source of proteins, carbohydrates, lipids, trace elements as well as water and, thus, provide a virtuous milieu for the growth of microbes. The obstinate microbial growth augments the degradation process and is amplified with the passage of time and improper storage of the biological materials. Degradation of these biological materials carriages a huge challenge in the downstream processes of forensic DNA typing technique, such as short tandem repeats (STR) DNA typing. Microbial degradation yields improper or no PCR amplification, heterozygous peak imbalance, DNA contamination from non-human sources, degradation of DNA by microbial by-products, etc. Consequently, the most precise STR DNA typing technique is nullified and definite opinion can be hardly given with degraded forensic exhibits. Thus, suitable precautionary measures should be taken for proper storage and processing of the biological exhibits to minimize their decaying process by micro-organisms.

The Use of Vacuum Dressings for Dead Space Management in Deep Surgical Site Infections Allows Implant and Bone Graft Retention

STUDY DESIGN

Retrospective, descriptive study.

OBJECTIVES

Managing early surgical site infection following elective lumbar spine surgery remains a challenge with controversy regarding retention of instrumentation and bone graft. Wound closure may also pose considerable challenges. We aim to report on our method of managing deep surgical site infections complicating elective spine surgery with surgeon assembled deep vacuum dressings. Identification of causative organisms with their sensitivities was a secondary objective.

METHODS

Patients were identified from a prospectively maintained, single-surgeon database from 2003-2015. Patients who had an infective or trauma related diagnosis, cervical procedures, and were younger than 18 years were excluded. Records were reviewed to identify bacteriology, laboratory tests performed, antibiotics administered, and type and frequency of surgical management. One thousand two hundred twenty patients qualified for inclusion, with 19 identified as having developed acute wound sepsis.

RESULTS

All patients had surgical debridement on the day of presentation and the majority of wounds were managed with a vacuum dressing. In all but 1 patient was instrumentation retained. Specimens for culture were taken at each debridement and antibiotics changed accordingly. Patients received a minimum 6 weeks of antibiotics.

CONCLUSIONS

The management of deep surgical site infection is labor intensive and frustrating for both surgeon and patient due to the unexpected prolonged admission. Management goals are identification and eradication of the causative organism with subsequent healing of the surgical wound. This process is enhanced with the use of negative-suction dressings made from theatre stock replaced at regular intervals and allows retention of bone graft and instrumentation in the majority of cases.

Beta-Hemolytic Bacteria Selectively Trigger Liposome Lysis, Enabling Rapid and Accurate Pathogen Detection

For more than a century, blood agar plates have been the only test for beta-hemolysis. Although blood agar cultures are highly predictive for bacterial pathogens, they are too slow to yield actionable information. Here, we show that beta-hemolytic pathogens are able to lyse and release fluorophores encapsulated in sterically stabilized liposomes whereas alpha and gamma-hemolytic bacteria have no effect. By analyzing fluorescence kinetics, beta-hemolytic colonies cultured on agar could be distinguished in real time with 100% accuracy within 6 h. Additionally, end point analysis based on fluorescence intensity and machine-extracted textural features could discriminate between beta-hemolytic and cocultured control colonies with 99% accuracy. In broth cultures, beta-hemolytic bacteria were detectable in under an hour while control bacteria remained negative even the next day. This strategy, called beta-hemolysis triggered-release assay (BETA) has the potential to enable the same-day detection of beta-hemolysis with single-cell sensitivity and high accuracy.

Reclassification of Phycicola gilvus (Lee et al. 2008) and Leifsonia pindariensis (Reddy et al. 2008) as Microterricola gilva comb. nov. and Microterricola pindariensis comb. nov. and emended description of the genus Microterricola

The taxonomic positions of Microterricola viridarii JCM 15926T, Phycicola gilvus DSM 18319T and Leifsonia pindariensis JCM 15132T were re-examined. Phylogenetic analysis and 16S rRNA gene sequence similarities revealed that all three strains are closely related with each other and form a monophyletic cluster with high sequence similarity (99.2 -99.9 %). A dendrogram constructed based on the protein spectra generated by matrix-assisted laser desorption/ionization time-of-flight mass spectroscopy also displayed close clustering of these three strains. The fatty acid profiles of three strains were very similar to each other and contained branched fatty acids (anteiso-C15 : 0, anteiso-C17 : 0 and iso-C16 : 0) as the predominant cellular fatty acids. The polar lipid profiles of the three stains were similar and consisted of diphosphatidylglycerol, phosphatidylglycerol and phosphatidylcholine as major polar lipids and an unknown lipid. Comparisons of morphological, chemotaxonomic and physiological data of Microterricola viridarii JCM 15926T, Leifsonia pindariensis JCM 15132T and Phycicola gilvus DSM 18319T are in agreement with the features of a common genus. DNA-DNA hybridization data generated during this study showed less than 70 % reassociation value with each other indicating that they are different at species level. Based on the present study, we conclude that Phycicola gilvus DSM 18319T and Leifsonia pindariensis JCM 15132T should be reclassified under the genus Microterricola, since this genus has the nomenclatural priority, and reclassified as Microterricolagilva comb. nov. (type strain SSWW-21T=DSM 18319T=KCTC 19185T=JCM 30550T) and Microterricolapindariensis comb. nov. (type strain PON10T=LMG 24222T=JCM 15132T=MTCC9128T). An emended description of the genus Microterricola is also presented.

Invasive Pneumococcal Disease in Children in Tonga

In Tonga, pneumococcal conjugate vaccine is not a scheduled immunization. We identified all children in Tonga with invasive pneumococcal disease from 2010 to 2013. The average annual invasive pneumococcal disease incidence rate was 113/100,000 (<2 years), 50/100,000 (<5 years) and 25/100,000 (<15 years). The case fatality rate (<5 years) was 25%. The incidence rate and high case fatality rate indicate the need for pneumococcal conjugate vaccine.

Real-time qPCR improves meningitis pathogen detection in invasive bacterial-vaccine preventable disease surveillance in Fiji

As part of the World Health Organization Invasive Bacterial-Vaccine Preventable Diseases (IB-VPD) surveillance in Suva, Fiji, cerebrospinal fluid (CSF) samples from suspected meningitis patients of all ages were examined by traditional methods (culture, Gram stain, and latex agglutination for bacterial antigen) and qPCR for Streptococcus pneumoniae, Neisseria meningitidis, and Haemophilus influenzae. Of 266 samples tested, pathogens were identified in 47 (17.7%). S. pneumoniae was the most common pathogen detected (n = 17) followed by N. meningitidis (n = 13). The use of qPCR significantly increased detection of IB-VPD pathogens (P = 0.0001): of 35 samples that were qPCR positive for S. pneumoniae, N. meningitidis, and H. influenzae, only 10 were culture positive. This was particularly relevant for N. meningitidis, as only 1/13 cases was culture positive. Molecular serotyping by microarray was used to determine pneumococcal serotypes from 9 of 16 (56%) of samples using DNA directly extracted from CSF specimens. Results indicate that qPCR significantly increases detection of S. pneumoniae, N. meningitidis, and H. influenzae in CSF, and that application of molecular diagnostics is a feasible way to enhance local and global surveillance for IB-VPD.

Elevated salivary IgA, decreased anxiety, and an altered oral microbiota are associated with active participation on an undergraduate athletic team

BACKGROUND

Previous reports indicate that regular, but not excessive, exercise can moderate the response to anxiety and alter the immune response, therefore we hypothesized that college student athletes who were actively participating on an NCAA Division III athletics team ("in-season") would have lower levels of anxiety and higher salivary IgA levels than similar college athletes who were in their "off-season". NCAA Division III athletes participate in athletics at a level of intensity that is more moderate compared to other NCAA divisions. Alterations in the microbiome have been associated with alterations in psychosocial well-being and with exercise. Therefore, we also proposed that the oral microbiota would be different in "in-season" versus "off-season" athletes.

METHOD

In this pilot study, nineteen female students participating on a NCAA Division III athletic team (hockey="in-season"; soccer="off-season") were compared for level of fitness (modified Balke test of VO₂ max), salivary IgA levels by immunoassay, anxiety (using a GAD-7 survey), salivary cortisol levels by immunoassay, and numbers of culturable bacteria by growth of CFU/ml on blood agar, mitis salivarius agar and Staphylococcus 110 agar.

RESULTS

The proportion of subjects reporting "severe anxiety" on an anxiety scale (GAD-7) were significantly greater in the "off-season" group compared to the "in-season" group (p=0.047, Chi-squared test). "In-season" athletes had significantly higher salivary IgA/total protein levels than "off-season" athletes (one-sided Student's t-test; p=0.03). Cortisol levels were not significantly different in the two groups. The total culturable bacteria counts were higher among "in-season" athletes (p=0.0455, Wilcoxon Rank Sum test), as measured by CFUs on blood agar plates, an estimate of total culturable bacteria, including pathogenic and non-pathogenic bacteria. In contrast, there was a decrease in the growth of bacteria from the oral cavity of the "in-season" athletes, when the growth of bacteria on mitis salivarius agar (primarily oral streptococcus) was measured (p=0.0006, Wilcoxon Rank Sum test). There was a negative correlation (Spearman Rank correlation coefficient=-0.651, p=0.0018 one-sided) between high IgA levels and the growth of bacteria on mitis salivarius agar in the combined group of "in-season" and "off-season" athletes, suggesting a protective response of high IgA levels to the typical oral pathogenic bacteria. Anxiety levels (GAD-7) in the "in-season" group were positively correlated with growth of oral bacteria on blood agar (Spearman Rank correlation coefficient of 0.622 for "in-season", p value=0.033 one-sided) and mitis salivarius agar (Spearman Rank correlation coefficient=0.671 for "in-season, p value=0.021 one-sided), and negatively correlated in "off-season" athletes on blood agar (-0.689 for "off-season", p value=0.028 one-sided), supporting the hypothesis that the microbiota are distinct in "in-season" and "off-season" athletes and may be associated with anxiety levels.

CONCLUSION

These findings are supportive of the hypothesis that participation in college level athletics has a positive effect on student-athlete health, specifically enhanced protective oral immunity, reduced anxiety, and alterations in oral microbial populations.

Throat culture positivity rate and antibiotic susceptibility pattern of beta-hemolytic streptococci in children on secondary prophylaxis for rheumatic heart disease

Background

Among children diagnosed to have chronic rheumatic valvular heart disease (RHD) in Ethiopia, many have been observed to develop recurrence of rheumatic fever (RF) despite secondary prophylaxis. This study determined the throat culture positivity rate and drug susceptibility pattern of beta hemolytic streptococci (BHS) isolated from children attending a specialized cardiac clinic in Ethiopia.

Methods

Throat swabs were collected from 233 children receiving benzathine penicillin injection as secondary prophylaxis for RHD and cultured. The bacterial isolates were characterized using Matrix Assisted Laser Desorption/Ionization-Time of Flight (MALDI-TOF) mass spectrometry. Drug susceptibility was tested with the Kirby Bauer disc diffusion method. Anti-streptolysin O (ASO) titers were determined using ASO latex reagents.

Results

The throat culture positivity rate for BHS was 24 % (56/233). Among the BHS bacterial strains isolated, four were characterized as S. pyogenes and another four as S. dysgalactiae subsp. equisimilis (Lancefield group A, C and G). All BHS were susceptible to penicillin except one isolate of S. agalactiae. Among 233 children enrolled, 46(19.7 %) showed increased ASO titer. Children who received antibiotic prophylaxis within 2-weeks of last injection had significantly lower BHS throat culture positivity rate than those injected every 4-weeks (p = 0.02). Children who missed at least one prophylaxis within the last 6 months had a higher BHS culture positivity rate than those who did not miss any (p = 0.0003).

Conclusions

The presence of groups A, C and G streptococci in the throat of children under secondary prophylaxis for RHD and increased ASO titer suggests failure of the regimen. This calls for further investigation into the causes of inadequate prophylaxis (including bioavailability of drugs used, optimal duration and patient compliance) and intervention.

Study of the impact of cranberry extract on the virulence factors and biofilm formation by Enterococcus faecalis strains isolated from urinary tract infections

Drinking of cranberry fruit juice and application of commercial preparations containing the cranberry extracts are recommended in the prevention and treatment of urinary tract infections (UTIs), especially in women with recurrent UTIs. Many studies focus on the activity of cranberries against uropathogenic Escherichia coli (E. coli) strains. However, the knowledge of the cranberry effect on Gram-positive Enterococcus faecalis (E. faecalis) is limited. Therefore, the aim of our study was to establish the activity of commercial concentrated cranberry extract on the growth, virulence factors and biofilm formation of E. faecalis strains isolated from urine. Minimal inhibitory concentrations (MICs) of cranberry extract were determined by the broth microdilution method. Disc diffusion method was used to determine antimicrobial susceptibility. The impact of cranberry extract on bacterial survival, hydrophobicity, synthesis of lipase, lecithinase, DNase, hemolysin, gelatinase and biofilm mass was determined. Results show that cranberry extract inhibits the growth, enzymatic activities of bacteria and limits biofilm formation. The antibacterial activities of the studied cranberry extract confirm that it could be successfully used in prevention of UTIs caused by E. faecalis.

Pneumococcal infection among hospitalized Egyptian children

AIM

We aimed to describe the detection rate spectrum of clinical manifestations, and outcome of pneumococcal disease in children younger than 5 years admitted to the largest referral pediatric hospital in Egypt.

MATERIALS AND METHODS

This was a hospital-based study to detect laboratory-confirmed Streptococcus pneumoniae cases among children younger than 5 years. Data on demographic characteristics, clinical diagnosis, comorbidities, diagnostic tests, antibiotic resistance, and clinical outcome were collected during the study years from 2008 to 2011.

RESULTS

During the 4-year study period, 22 018 cases younger than 5 years had cultures performed at Cairo University Pediatric Hospital microbiology laboratory. We estimated the annual detection rate of total Streptococcus pneumonia infection to be 54.5/100 000. The incidence of invasive pneumococcal disease (IPD) was half the incidence of non-IPD (18.2 and 36.4/100 000, respectively). Infants of 1 year or younger were statistically more vulnerable to Streptococcus pneumonia infection compared with children between 1 and 5 years of age (annual rate: 110.5/100 000 and 21.6/100 000, respectively). The overall pneumococcal annual case fatality was 33.3% and was higher in IPD (75%) than in non-IPD (12.5%) cases. There was an obviously increasing trend of the pneumococcal detection rate throughout the 4 years of the study (P<0.0001).

CONCLUSION AND RECOMMENDATIONS

Our results confirm the substantial and increasing pneumococcal infection, the emerging of multidrug resistant isolates, and the vulnerability of the younger age group and high-risk population, which calls for a national surveillance to inform policy and decision-making before national wide vaccine introduction.

Involvement of soil bacteria in ABO blood mistyping

The current study investigated whether ABO blood mistyping of human biological samples is induced by soil bacteria. A total of 380 bacterial strains were isolated from 50 discrete soil samples using human blood agar, and glycosidase activity evaluated for all strains using 4-nitropheny glycosides (4-nitrophenyl n-acetyl-α-D-galactosaminide, 4-nitrophenyl-α-D-galactopyranoside, 4-nitrophenyl-α-L-fucopyranoside) as substrates. Thirteen strains possessed α-galactosidase activity, and 16S rRNA sequence analysis revealed a close relatedness to the genus Bacillus. An indirect competitive enzyme-linked immunosorbent assay confirmed seven strains exhibited type B antigen degradation activity. These results demonstrated that 1.8% of the bacteria isolated from soil, were Bacillus sp., possessed galactosidase activity, and had the potential to cause ABO blood mistyping.

Standard method for detecting upper respiratory carriage of Streptococcus pneumoniae: updated recommendations from the World Health Organization Pneumococcal Carriage Working Group

In 2003 the World Health Organization (WHO) convened a working group and published a set of standard methods for studies measuring nasopharyngeal carriage of Streptococcus pneumoniae (the pneumococcus). The working group recently reconvened under the auspices of the WHO and updated the consensus standard methods. These methods describe the collection, transport and storage of nasopharyngeal samples, as well as provide recommendations for the identification and serotyping of pneumococci using culture and non-culture based approaches. We outline the consensus position of the working group, the evidence supporting this position, areas worthy of future research, and the epidemiological role of carriage studies. Adherence to these methods will reduce variability in the conduct of pneumococcal carriage studies undertaken in the context of pneumococcal vaccine trials, implementation studies, and epidemiology studies more generally so variability in methodology does not confound the interpretation of study findings.

Community acquired bacteremia in young children from central Nigeria--a pilot study

BACKGROUND

Reports of the etiology of bacteremia in children from Nigeria are sparse and have been confounded by wide spread non-prescription antibiotic use and suboptimal laboratory culture techniques. We aimed to determine causative agents and underlying predisposing conditions of bacteremia in Nigerian children using data arising during the introduction of an automated blood culture system accessed by 7 hospitals and clinics in the Abuja area.

METHODS

Between September 2008 and November 2009, we enrolled children with clinically suspected bacteremia at rural and urban clinical facilities in Abuja or within the Federal Capital Territory of Nigeria. Blood was cultured using an automated system with antibiotic removing device. We documented clinical features in all children and tested for prior antibiotic use in a random sample of sera from children from each site.

RESULTS

969 children aged 2 months-5 years were evaluated. Mean age was 21±15.2 months. All children were not systematically screened but there were 59 (6%) children with established diagnosis of sickle cell disease and 42 (4.3%) with HIV infection. Overall, 212 (20.7%) had a positive blood culture but in only 105 (10.8%) were these considered to be clinically significant. Three agents, Staphylococcus aureus (20.9%), Salmonella typhi (20.9%) and Acinetobacter (12.3%) accounted for over half of the positive cultures. Streptococcus pneumoniae and non-typhi Salmonellae each accounted for 7.6%. Although not the leading cause of bacteremia, Streptococcus pneumoniae was the single leading cause of all deaths that occurred during hospitalization and after hospital discharge.

CONCLUSION

S. typhi is a significant cause of vaccine-preventable morbidity while S. pneumoniae may be a leading cause of mortality in this setting. This observation contrasts with reports from most other African countries where non-typhi Salmonellae are predominant in young children. Expanded surveillance is required to confirm the preliminary observations from this pilot study to inform implementation of appropriate public health control measures.

Analysis of beta-hemolysis in human blood agars by Streptococcus pyogenes

The aim of the study was to assess the reliability of human blood agar media (HuBA) in identifying Streptococcus pyogenes by hemolysis analysis. We analyze several factors that might affect the accuracy of HuBA media for microbial analysis, including incubation time, blood group, Rh factor and presence of antistreptolysin-o.

Pneumococcal nasopharyngeal carriage following reduced doses of a 7-valent pneumococcal conjugate vaccine and a 23-valent pneumococcal polysaccharide vaccine booster

This study was conducted to evaluate the effect of a reduced-dose 7-valent pneumococcal conjugate vaccine (PCV) primary series followed by a 23-valent pneumococcal polysaccharide vaccine (23vPPS) booster on nasopharyngeal (NP) pneumococcal carriage. For this purpose, Fijian infants aged 6 weeks were randomized to receive 0, 1, 2, or 3 PCV doses. Within each group, half received 23vPPS at 12 months. NP swabs were taken at 6, 9, 12, and 17 months and were cultured for Streptococcus pneumoniae. Isolates were serotyped by multiplex PCR and a reverse line blot assay. There were no significant differences in PCV vaccine type (VT) carriage between the 3- and 2-dose groups at 12 months. NP VT carriage was significantly higher (P, <0.01) in the unvaccinated group than in the 3-dose group at the age of 9 months. There appeared to be a PCV dose effect in the cumulative proportion of infants carrying the VT, with less VT carriage occurring with more doses of PCV. Non-PCV serotype (NVT) carriage rates were similar for all PCV groups. When groups were pooled by receipt or nonreceipt of 23vPPS at 12 months, there were no differences in pneumococcal, VT, or NVT carriage rates between the 2 groups at the age of 17 months. In conclusion, there appeared to be a PCV dose effect on VT carriage, with less VT carriage occurring with more doses of PCV. By the age of 17 months, NVT carriage rates were similar for all groups. 23vPPS had no impact on carriage, despite the substantial boosts in antibody levels.

Comparison of citrated human blood, citrated sheep blood, and defibrinated sheep blood Mueller-Hinton agar preparations for antimicrobial susceptibility testing of Streptococcus pneumoniae isolates

The use of Mueller-Hinton agar supplemented with citrated human or citrated sheep blood was compared with the use of routinely used Mueller-Hinton agar supplemented with defibrinated sheep blood for antimicrobial susceptibility testing of Streptococcus pneumoniae. The alternate supplements were found to be unsatisfactory, particularly for testing resistant isolates, and therefore are not recommended.

Hair sheep blood, citrated or defibrinated, fulfills all requirements of blood agar for diagnostic microbiology laboratory tests

BACKGROUND

Blood agar is used for the identification and antibiotic susceptibility testing of many bacterial pathogens. In the developing world, microbiologists use human blood agar because of the high cost and inhospitable conditions for raising wool sheep or horses to supply blood. Many pathogens either fail to grow entirely or exhibit morphologies and hemolytic patterns on human blood agar that confound colony recognition. Furthermore, human blood can be hazardous to handle due to HIV and hepatitis. This study investigated whether blood from hair sheep, a hardy, low-maintenance variety of sheep adapted for hot climates, was suitable for routine clinical microbiology studies.

METHODS AND FINDINGS

Hair sheep blood obtained by jugular venipuncture was anticoagulated by either manual defibrination or collection in human blood bank bags containing citrate-phosphate-dextrose. Trypticase soy 5% blood agar was made from both forms of hair sheep blood and commercial defibrinated wool sheep blood. Growth characteristics, colony morphologies, and hemolytic patterns of selected human pathogens, including several streptococcal species, were evaluated. Specialized identification tests, including CAMP test, reverse CAMP test, and satellite colony formation with Haemophilus influenzae and Abiotrophia defectiva were also performed. Mueller-Hinton blood agar plates prepared from the three blood types were compared in antibiotic susceptibility tests by disk diffusion and E-test.

CONCLUSIONS

The results of all studies showed that blood agar prepared from citrated hair sheep blood is suitable for microbiological tests used in routine identification and susceptibility profiling of human pathogens. The validation of citrated hair sheep blood eliminates the labor-intensive and equipment-requiring process of manual defibrination. Use of hair sheep blood, in lieu of human blood currently used by many developing world laboratories and as an alternative to cost-prohibitive commercial sheep blood, offers the opportunity to dramatically improve the safety and accuracy of laboratory diagnosis of pathogenic bacteria in resource-poor countries.

Burden of acute sore throat and group A streptococcal pharyngitis in school-aged children and their families in Australia

OBJECTIVE

The objective of this study was to determine the incidence, transmission, carriage, and risk factors for group A streptococcal pharyngitis in school-aged children and their families.

METHODS

A 16-month, prospective, family-based cohort study was undertaken from August 2001 through December 2002 in Melbourne, Australia. A total of 202 families (853 people) with at least 1 child aged 3 to 12 years were randomly selected from 3 primary care practices across suburban Melbourne to collect surveillance data for acute group A streptococcal pharyngitis, including serology for index and secondary cases and intermittent carriage data. Cohort retention was 97% for 16 months.

RESULTS

The incidence of acute sore throat, group A streptococcal swab-positive pharyngitis, and serologically confirmed group A streptococcal pharyngitis was 33, 13, and 8 per 100 child-years, respectively, for school-aged children (5-12 years) and 60, 20, and 15 per 100 family-years, respectively. Sore throat was less common in adults than children, but adults with sore throat were as likely as children to have group A streptococcal culture-positive or serologically proven pharyngitis. In families who had a primary case, 43% had at least 1 secondary case, and in family members who were at risk, 13% contracted a secondary case. The spring, summer, and winter carriage rates for children were 13%, 8%, and 16%, respectively, and for adults the rate was 2% across all seasons.

CONCLUSIONS

Group A streptococcal pharyngitis is still common, and the peak incidence occurs in school-aged children. However, the incidence in adults is higher than expected, and the number of secondary cases in families may be an important factor when considering the potential benefits of treatment.