Authors:Bosede Titilope Bamigboye, Olugbenga Adekunle Olowe, and Samuel Sunday Taiwo
The use of vancomycin for treatment of serious infections caused by MRSA strains has resulted in emergence of vancomycin-resistant Staphylococcus aureus (VRSA) in clinical settings. Following our previous report of phenotypic VRSA in Nigeria, the current study attempts to determine the genetic basis underlying this resistance. Over a period of 6 months, non-duplicate clinical S. aureus isolates from 73 consecutive patients with infective conditions at Ladoke Akintola University of Technology Teaching Hospital, Osogbo were tested against a panel of eight selected antibiotics by disk diffusion test. The Epsilom test strip was used to determine vancomycin minimum inhibitory concentration (MIC) and polymerase chain reaction (PCR) assay to amplify nuc, mecA, vanA, and vanB genes. Of 73 isolates, 61 (83.6%) had MIC of ≤2 μg/ml, 11 (15.1%) had 4–8 μg/ml and 1 (1.4%) had 16 μg/ml. The mecA gene was detected in 5 (6.8%) isolates but none contained vanA or vanB genes. Both vancomycin-susceptible and intermediate isolates were resistant to multiple antibiotics, while the only vancomycin resistant isolate was resistant to all eight antibiotics. The result confirms the occurrence of phenotypic vancomycin intermediate-resistant S. aureus (VISA) and VRSA infections in Nigeria, but the molecular basis will require further investigation.
Authors:Miriam Hilbert, Isabella Csadek, Ulrike Auer, and Friederike Hilbert
In the past, the horizontal transfer of antimicrobial resistance genes was mainly associated with conjugative plasmids or transposons, whereas transduction by bacteriophages was thought to be a rare event. In order to analyze the likelihood of transduction of antimicrobial resistance in the field of clinical veterinary medicine, we isolated phages from Escherichia coli from a surgery suite of an equine clinic. In a pilot study, the surgery suite of a horse clinic was sampled directly after surgery and subsequently sampled after cleaning and disinfection following a sampling plan based on hygiene, surgery, and anesthesia. In total, 31 surface sampling sites were defined and sampled. At 24 of these 31 surface sampling sites, coliphages were isolated. At 12 sites, coliphages were found after cleaning and disinfection. Randomly selected phages were tested for their ability of antimicrobial resistance transduction. Ten of 31 phages were detected to transfer antimicrobial resistance. These phages most often transduced resistance to streptomycin, encoded by the addA1 gene (n = 9), followed by resistance to chloramphenicol by cmlA (n = 3) and ampicillin (n = 1). This is, to the best of our knowledge, the first report on antimicrobial resistance-transferring bacteriophages that have been isolated at equine veterinary clinics.
Authors:A. M. Abd El-Gawad, M. Zotti, T. C. Sarker, S. Mazzoleni, and G. Bonanomi
Unlike vagile organisms, plants perform a wide range of phenotypic responses to cope with environmental stresses. A special case of interaction with external factors is the ability of plants to recognize genetic relatedness of neighbour plants, actually well known as kin recognition. The present work aimed to provide a valuable contribution to the field of kin recognition in plants through a common garden experiment. To avoid bias involved in pot experiments, we perform an experiment in unconstrained root growth conditions comparing the development of coupled kin, non-kin and solitary plants of Xanthium italicum. Biometrics of plants with different genetic relatedness were measured, then architecture and competitive interaction were assessed using the relative interaction index (RII) for above and belowground portions of plants. X. italicum showed different allocation depending on the neighbourhood. Root biomass was declined in plants growing with kin compared to non-kin coupled plants, while plants coupled with kin allocated more shoot than roots compared to solitary plants. RII explains phenotypic response of decreased competition in roots rather than in shoots. Despite high values of RII for the aboveground portion, the architectural analysis of shoot, number, angle and length of branches and roots reveals dramatic but indistinctive change in the structure of plants growing near kin or non kin compared to a solitary plant. These results confirm phenotypic responses of kin recognition in unconstrained environment.
Authors:Sachin K. Garg, Kyle Lu, John Duncan, Lance R. Peterson, and Oliver Liesenfeld
Clostridium difficile infection is a significant health burden, and innovative solutions are needed to shorten time to diagnosis and improve infection control. We evaluated the performance of the cobas® Cdiff test for use on the cobas® Liat® System (cobas® Liat® Cdiff), a single-sample, on-demand, and automated molecular solution with a 20-min turnaround time. The limit of detection was 45–90 colony-forming units (CFUs)/swab for toxigenic strains that covered the most prevalent toxinotypes, including the hypervirulent epidemic 027/BI/NAP1 strain. Using 442 prospectively collected clinical stool specimens, we compared the performance of the cobas® Liat® Cdiff to direct culture and to the cobas® Cdiff test on the cobas® 4800 System (cobas® 4800 Cdiff) – a mediumthroughput molecular platform. The sensitivity and specificity of the cobas® Liat® Cdiff compared to direct culture were 93.1% and 95.1%, respectively, and this performance did not statistically differ from the cobas® 4800 Cdiff (P > 0.05). Direct correlation of the cobas® Liat® and cobas® 4800 Cdiff tests yielded overall percent agreement of 98.6%. The test performance, automation, and turnaround time of the cobas® Liat® Cdiff enable its use for on-demand and out-of-hours testing as a complement to existing batch testing solutions like the cobas® 4800 Cdiff.
Authors:J. Leszczyńska, Ł. Głowacki, and M. Grzybkowska
The biodiversity and species richness of benthic macroinvertebrate assemblages are under the strong pressure of environmental variables compounded with geographical and historical processes. Numerous studies that have investigated biodiversity and assemblage stability have shown the importance of choosing proper methodologies and paradigms. Consequently, the use of diversity measures and the partitioning of biodiversity at different spatial and temporal scales are of particular significance. Within habitats, only those species whose preferences remain within a tolerable range of the variability of abiotic factors are able to survive. The structure of biocoenosis at the local scale is determined mainly by current velocity/discharge, granulometry of the inorganic bottom substrate, quantity and quality of particulate organic matter, as well as water quality variables. Dispersion plays a key role in shaping regional diversity gradients, which supports the permanent inflow of individuals and their exchange between riverine basins. However, dispersion is also one of the basic aspects of the saturation/non-saturation of local communities with species from the regional species pool; a respective concept tries to determine how, why and to what degree local species richness is dependent on regional species richness.
Authors:Irène Pegha-Moukandja, Roméo-Karl Imboumy-Limoukou, Nina Tchitoula-Makaya, Augustin-Ghislain Mouinga-Ondeme, Jean Claude Biteghe-Bi-Essone, Dieudonne Nkoghe Mba, Jean-Bernard Lekana-Douki, and Fousseyni S. Toure Ndouo
Plasmodium falciparum merozoite antigens (PfMAgs) play an essential role in the development of immunity to malaria. Currently, P. falciparum: protein 113 (Pf 113), apical membrane antigen 1 (AMA1), erythrocyte binding antigens (EBA175), and reticulocyte binding protein homologue 5 (RH5) are among the most PfMAgs studied. A comparative analysis of naturally acquired antibodies against these antigens in children would increase our knowledge about the development of protective immunity.
Analysis of antibodies to Pf113, PfAMA1, PfEBA175, and PfRH5 was conducted in rural population during 2013 and 2014. Both prevalence and levels of total IgG anti-PfAMA1 were higher than that of IgG anti-PfEBA175, anti-PfRH5, and anti-Pf113. Seroconversion to PfAMA1 and PfEBA175 occurred moderately in young children and reached to the maximum in adolescent and in adults. High prevalence of IgG anti-Pf113 was observed in young children of 3 to 6 years old in 2013. The four antigens were recognized by IgG 1, 2, 3, and 4 antibodies from a large proportion of the subjects, and all of them induced high levels of specific IgG1 against PfAMA1, PfEBA175, fewer by Pf113 and PfRH5.
Many asymptomatic children had specific IgG1 recognizing multiple antigens, and these IgG1 antibodies could be associated with a reduced risk of developing malaria symptoms.
Authors:Hagen Frickmann, Andreas Hahn, Norbert Georg Schwarz, Ralf Matthias Hagen, Denise Dekker, Rebecca Hinz, Volker Micheel, Benedikt Hogan, Jürgen May, and Raphael Rakotozandrindrainy
Direct growth on blood and screening agar for methicillin-resistant Staphylococcus aureus (MRSA) at a tropical surveillance site was compared with broth enrichment and subsequent growth on selective MRSA agar after international sample transport.
In Madagascar, 1548 swabs from an MRSA surveillance study were assessed for growth on Columbia blood agar enriched with 5% sheep blood and MRSA screening agar at the surveillance site with subsequent cold storage of the samples and shipment to Germany. In Germany, 1541 shipped samples were analyzed by non-selective broth enrichment with subsequent culture on MRSA selective agar.
A total of 28 MRSA isolates were detected. Of these, 20 strains were isolated from direct culture on blood and MRSA screening agars at the surveillance site, 24 MRSA strains were isolated using the broth enrichment method in Germany, and 16 MRSA strains were identified by both approaches.
In spite of the observed die-off of individual strains due to long-term storage and transport, broth enrichment with subsequent screening on MRSA selective agar after international sample shipment led to comparable sensitivity of MRSA detection like streaking on blood and MRSA agar at the tropical surveillance site.
Authors:Hagen Frickmann, Kerstin Köller, Irina Veil, Mirjam Weise, Alicja Ludyga, Norbert Georg Schwarz, Philipp Warnke, and Andreas Podbielski
This study assesses the clinical relevance of vancomycin-susceptible enterococci in bacteremic patients and compares it with bacteremia due to Staphylococcus aureus and Escherichia coli.
During a 5-year-study interval, clinical and diagnostic features of patients with enterococcal bacteremia were compared to those of patients with E. coli or S. aureus bacteremia. Each patient was only counted once per hospital stay.
During the 5-year study interval, data from 267 patients with enterococcal bacteremia and from 661 patients with bacteremia due to E. coli or S. aureus were evaluated. In spite of a comparable risk of death, patients with enterococci more frequently needed catecholamines and invasive ventilation. Furthermore, enterococci were more frequently associated with a mixed bacterial flora in bloodstream infections. While fatal sepsis due to E. coli and S. aureus was associated with typical shock symptoms, this association was not confirmed for enterococci.
Although enterococcal bacteremia is associated with a risk of dying comparable to that with bacteremia due to E. coli and S. aureus, a lower pathogenic potential of enterococci in bloodstream has to be acknowledged. Enterococci in the bloodstream are more likely to be an epiphenomenon of impending death than its major cause.
Authors:Ali Asghar Ayatollahi, Abolfazl Amini, Somayeh Rahimi, Saeid Rahbar Takrami, Reza Kazemi Darsanaki, and Muhammad Sadeqi Nezhad
Nosocomial infections are one of the most common causes of death in hospitals. This study aimed to determine the prevalence of gram-negative bacilli isolated from the equipment in hospital wards of the Golestan province, in the year 2015. In this crosssectional study in 2015, 1980 samples from medical and nonmedical equipment and surfaces were collected from the wards of 13 teaching hospitals, in the Golestan province. Samples were inoculated into eosin methylene blue agar and blood agar culture media and isolated colonies were identified by standard biochemical tests. The obtained results were then analyzed using SPSS 22 software and χ2 test. Among 1980 isolated samples, 601 samples (30.35%) were infected with gram-negative bacilli while Enterobacter aerogenes (37.27%) was responsible for most of the contaminations. The highest rate of infection was observed in the intensive care unit (33.1%), and the highest level of contamination in the medical equipment was associated with laryngoscope and its blade (10.48%), as well as ECG sensor and its monitoring connector (6.65%). Meanwhile, phone (6.32%) and patients’ beds and linen (5.15%) had the highest level of contamination in the nonmedical equipment. Considering the high rates of gram-negative bacilli contamination in the hospital wards of the Golestan province, thorough hand washing as the main action for disinfection and sterilizing the equipment, as well as performing periodic cultivation alongside the use of standard guidelines for prevention and control of nosocomial infections, are recommended to reduce the level of contamination.
Authors:Dora Romero-Salas, Cosme Alvarado-Esquivel, Gladys Domínguez-Aguilar, Anabel Cruz-Romero, Nelly Ibarra-Priego, Carolina Barrientos-Salcedo, Mariel Aguilar-Domínguez, Rodolfo Canseco-Sedano, Luz Teresa Espín-Iturbe, Luis Francisco Sánchez-Anguiano, Jesús Hernández-Tinoco, and Adalberto A. Pérez de León
We aimed to determine the seroprevalence of infection with Neospora caninum, Leptospira, and bovine herpesvirus type 1 and risk factors associated with these infections in water buffaloes in Veracruz State, Mexico. Through a cross-sectional study, 144 water buffaloes (Bubalus bubalis) raised in 5 ranches of Veracruz were examined for anti-N. caninum and anti-bovine herpesvirus type 1 antibodies by enzyme immunoassays, and anti-Leptospira interrogans antibodies by microscopic agglutination test.
Of the 144 buffaloes studied, 35 (24.3%) were positive for N. caninum, 50 (34.7%) for Leptospira, and 83 (57.6%) for bovine herpes virus. The frequencies of leptospiral serovars in buffaloes were as follows: 18.7% for Muenchen (n = 27), 10.4% for Hardjo LT (n = 15), 9.0% for Pyrogenes (n = 13), and 4.8% for Icterohaemorrhagiae (n = 7). Seropositive buffaloes were found in all 5 ranches studied. Logistic regression showed that cohabitation of buffaloes with cows was associated with infection with Leptospira (odds ratio [OR], 2.2; 95% confidence interval [CI], 1.04–4.5; P = 0.03) and bovine herpesvirus (OR, 12.0; 95% CI, 4.0–36.2; P >; 0.01).
This is the first study that provides serological evidence of N. caninum, Leptospira, and bovine herpesvirus type 1 infections in water buffaloes in Mexico. Our findings could be used to enhance preventive measures against these infections.