ResearchPad - microbial-control https://www.researchpad.co Default RSS Feed en-us © 2020 Newgen KnowledgeWorks <![CDATA[A prospective study of bloodstream infections among febrile adolescents and adults attending Yangon General Hospital, Yangon, Myanmar]]> https://www.researchpad.co/article/elastic_article_13833 Bloodstream infection (BSI) is common among persons seeking healthcare for severe febrile illness in low-and middle-income countries. Data on community-onset BSI are few for some countries in Asia, including Myanmar. Such data are needed to inform empiric antimicrobial treatment of patients and to monitor and control antimicrobial resistance. We performed a one year, prospective study collecting information and blood cultures from patients presenting with fever at a tertiary referral hospital in Yangon, Myanmar. We found that almost 10% of participants had a bloodstream infection, and that Salmonella enterica serovars Typhi and Paratyphi A were the most common pathogens. Typhoidal Salmonella were universally resistant to ciprofloxacin. More than half of Escherichia coli and Klebsiella pneumoniae were resistant to extended-spectrum cephalosporins and resistance to carbapenems was also identified in some isolates. We show that typhoid and paratyphoid fever are common, and fluoroquinolone resistance is widespread. Extended-spectrum cephalosporin resistance is common in E. coli and K. pneumoniae and carbapenem resistance is present. Our findings inform empiric antimicrobial management of severe febrile illness, underscore the value of routine use of blood cultures, indicate that measures to prevent and control enteric fever are warranted, and suggest a need to monitor and mitigate antimicrobial resistance among community-acquired pathogens.

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<![CDATA[A screening of the MMV Pathogen Box® reveals new potential antifungal drugs against the etiologic agents of chromoblastomycosis]]> https://www.researchpad.co/article/elastic_article_13863 Chromoblastomycosis (CBM) is a chronic subcutaneous mycosis caused by traumatic implantation of many species of black fungi. Due to the refractoriness of some cases and common recurrence of CBM, a more effective and less time-consuming treatment is mandatory. The aim of this study was to identify compounds with in vitro antifungal activity in the Pathogen Box® compound collection against different CBM agents. Synergism of these compounds with drugs currently used to treat CBM was also assessed. An initial screening of the drugs present in this collection at 1 μM was performed with a Fonsecaea pedrosoi clinical strain according to the EUCAST protocol. The compounds with activity against this fungus were also tested against other seven etiologic agents of CBM (Cladophialophora carrionii, Phialophora verrucosa, Exophiala jeanselmei, Exophiala dermatitidis, Fonsecaea monophora, Fonsecaea nubica, and Rhinocladiella similis) at concentrations ranging from 0.039 to 10 μM. The analysis of potential synergism of these compounds with itraconazole and terbinafine was performed by the checkerboard method. Eight compounds inhibited more than 60% of the F. pedrosoi growth: difenoconazole, bitertanol, iodoquinol, azoxystrobin, MMV688179, MMV021013, trifloxystrobin, and auranofin. Iodoquinol produced the lowest MIC values (1.25–2.5 μM) and MMV688179 showed MICs that were higher than all compounds tested (5 - >10 μM). When auranofin and itraconazole were tested in combination, a synergistic interaction (FICI = 0.37) was observed against the C. carrionii isolate. Toxicity analysis revealed that MMV021013 showed high selectivity indices (SI ≥ 10) against the fungi tested. In summary, auranofin, iodoquinol, and MMV021013 were identified as promising compounds to be tested in CBM models of infection.

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<![CDATA[Placental transfer of Letermovir &amp; Maribavir in the <i>ex vivo</i> human cotyledon perfusion model. New perspectives for <i>in utero</i> treatment of congenital cytomegalovirus infection]]> https://www.researchpad.co/article/elastic_article_11236 Congenital cytomegalovirus infection can lead to severe sequelae. When fetal infection is confirmed, we hypothesize that fetal treatment could improve the outcome. Maternal oral administration of an effective drug crossing the placenta could allow fetal treatment. Letermovir (LMV) and Maribavir (MBV) are new CMV antivirals, and potential candidates for fetal treatment.MethodsThe objective was to investigate the placental transfer of LMV and MBV in the ex vivo method of the human perfused cotyledon. Term placentas were perfused, in an open-circuit model, with LMV or MBV at concentrations in the range of clinical peak plasma concentrations. Concentrations were measured using ultraperformance liquid chromatography coupled with tandem mass spectrometry. Mean fetal transfer rate (FTR) (fetal (FC) /maternal concentration), clearance index (CLI), accumulation index (AI) (retention of each drug in the cotyledon tissue) were measured. Mean FC were compared with half maximal effective concentrations of the drugs (EC50(LMV) and EC50(MBV)).ResultsFor LMV, the mean FC was (± standard deviation) 1.1 ± 0.2 mg/L, 1,000-fold above the EC50(LMV). Mean FTR, CLI and AI were 9 ± 1%, 35 ± 6% and 4 ± 2% respectively. For MBV, the mean FC was 1.4 ± 0.2 mg/L, 28-fold above the EC50(MBV). Mean FTR, CLI and AI were 10 ± 1%, 50 ± 7% and 2 ± 1% respectively.ConclusionsDrugs’ concentrations in the fetal side should be in the range for in utero treatment of fetuses infected with CMV as the mean FC was superior to the EC50 for both molecules. ]]> <![CDATA[Substantial improvement of tetraene macrolide production in <i>Streptomyces diastatochromogenes</i> by cumulative drug resistance mutations]]> https://www.researchpad.co/article/elastic_article_7861 Tetraene macrolides remain one of the most reliable fungicidal agents as resistance of fungal pathogens to these antibiotics is relatively rare. The modes of action and biosynthesis of polyene macrolides had been the focus of research over the past few years. However, few studies have been carried out on the overproduction of polyene macrolides. In the present study, cumulative drug-resistance mutation was used to obtain a quintuple mutant G5-59 with huge tetraene macrolide overproduction from the starting strain Streptomyces diastatochromogenes 1628. Through DNA sequence analysis, the mutation points in the genes of rsmG, rpsL and rpoB were identified. Additionally, the growth characteristic and expression level of tetrRI gene (belonging to the large ATP binding regulator of LuxR family) involved in the biosynthesis of tetraene macrolides were analyzed. As examined with 5L fermentor, the quintuple mutant G5-59 grew very well and the maximum productivity of tetramycin A, tetramycin P and tetrin B was as high as 1735, 2811 and 1500 mg/L, which was 8.7-, 16- and 25-fold higher than that of the wild-type strain 1628, respectively. The quintuple mutant G5-59 could be useful for further improvement of tetraene macrolides production at industrial level.

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<![CDATA[Abrogation of pathogenic attributes in drug resistant <i>Candida auris</i> strains by farnesol]]> https://www.researchpad.co/article/elastic_article_7651 Candida auris, a decade old Candida species, has been identified globally as a significant nosocomial multidrug resistant (MDR) pathogen responsible for causing invasive outbreaks. Biofilms and overexpression of efflux pumps such as Major Facilitator Superfamily and ATP Binding Cassette are known to cause multidrug resistance in Candida species, including C. auris. Therefore, targeting these factors may prove an effective approach to combat MDR in C. auris. In this study, 25 clinical isolates of C. auris from different hospitals of South Africa were used. All the isolates were found capable enough to form biofilms on 96-well flat bottom microtiter plate that was further confirmed by MTT reduction assay. In addition, these strains have active drug efflux mechanism which was supported by rhodamine-6-G extracellular efflux and intracellular accumulation assays. Antifungal susceptibility profile of all the isolates against commonly used drugs was determined following CLSI recommended guidelines. We further studied the role of farnesol, an endogenous quorum sensing molecule, in modulating development of biofilms and drug efflux in C. auris. The MIC for planktonic cells ranged from 62.5–125 mM, and for sessile cells was 125 mM (4h biofilm) and 500 mM (12h and 24h biofilm). Furthermore, farnesol (125 mM) also suppresses adherence and biofilm formation by C. auris. Farnesol inhibited biofilm formation, blocked efflux pumps and downregulated biofilm- and efflux pump- associated genes. Modulation of C. auris biofilm formation and efflux pump activity by farnesol represent a promising approach for controlling life threatening infections caused by this pathogen.

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<![CDATA[Managing possible serious bacterial infection of young infants where referral is not possible: Lessons from the early implementation experience in Kushtia District learning laboratory, Bangladesh]]> https://www.researchpad.co/article/elastic_article_7649 Serious infections account for 25% of global newborn deaths annually, most in low-resource settings where hospital-based treatment is not accessible or feasible. In Bangladesh, one-third of neonatal deaths are attributable to serious infection; in 2014, the government adopted new policy for outpatient management of danger signs indicating possible serious bacterial infections (PSBI) when referral was not possible. We conducted implementation research to understand what it takes for a district health team to implement quality outpatient PSBI management per national guidelines.MethodsPSBI management was introduced as part of the Comprehensive Newborn Care Package in 2015. The study piloted this package through government health systems with limited partner support to inform scale-up efforts. Data collection included facility register reviews for cases seen at primary level facilities; facility readiness and provider knowledge and skills assessments; household surveys capturing caregiver knowledge of newborn danger signs and care-seeking for newborn illness; and follow-up case tracking, capturing treatment adherence and outcomes. Analysis consisted of descriptive statistics.ResultsOver the 15-month implementation period, 1432 young infants received care, of which 649 (45%) were classified as PSBI. Estimated coverage of care-seeking increased from 22% to 42% during the implementation period. Although facility readiness and providers’ skills increased, providers’ adherence to guidelines was not optimal. Among locally managed PSBI cases, 75% completed the oral antibiotic course and 15% received the fourth day follow-up. Care-seeking remained high among private providers (95%), predominantly village health doctors (over 80%).ConclusionsFacility readiness, including health care provider knowledge and skills were strengthened; future efforts should focus on improving provider adherence to guidelines. Social and behavior change strategies targeting families and communities should explore shifting care-seeking from private, possibly less-qualified providers. Strategies to improve private sector management of PSBI cases and improved linkages between private and public sector providers could be explored. ]]> <![CDATA[Virulence factors and antibiograms of <i>Escherichia coli</i> isolated from diarrheic calves of Egyptian cattle and water buffaloes]]> https://www.researchpad.co/article/elastic_article_8462 Diarrhea caused by Escherichia coli in calves is an important problem in terms of survivability, productivity and treatment costs. In this study, 88 of 150 diarrheic animals tested positive for E. coli. Of these, 54 samples had mixed infection with other bacterial and/or parasitic agents. There are several diarrheagenic E. coli pathotypes including enteropathogenic E. coli (EPEC), Shiga-toxin producing E. coli (STEC), enterotoxigenic E. coli (ETEC) and necrotoxigenic E. coli (NTEC). Molecular detection of virulence factors Stx2, Cdt3, Eae, CNF2, F5, Hly, Stx1, and ST revealed their presence at 39.7, 27.2, 19.3, 15.9, 13.6, 9.0, 3.4, and 3.4 percent, respectively. As many as 13.6% of the isolates lacked virulence genes and none of the isolate had LT or CNF1 toxin gene. The odds of isolating ETEC from male calves was 3.6 times (95% CI: 1.1, 12.4; P value = 0.042) that of female calves, whereas the odds of isolating NTEC from male calves was 72.9% lower (95% CI: 91.3% lower, 15.7% lower; P value = 0.024) than that in females. The odds of isolating STEC in winter was 3.3 times (95% CI: 1.1, 10.3; P value = 0.037) that of spring. Antibiograms showed 48 (54.5%) of the isolates to be multi-drug resistant. The percent resistance to tetracycline, streptomycin, ampicillin, and trimethoprim-sulfamethoxazole was 79.5, 67.0, 54.5, and 43.0, respectively. Ceftazidime (14.8%), amoxicillin-clavulanic acid (13.6%) and aztreonam (11.3%) showed the lowest resistance, and none of the isolates was resistant to imipenem. The results of this study can help improve our understanding of the epidemiological aspects of E. coli infection and to devise strategies for protection against it. The prevalence of E. coli pathotypes can help potential buyers of calves to avoid infected premises. The antibiograms in this study emphasizes the risks associated with the random use of antibiotics.

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<![CDATA[Adherence to antiretroviral therapy and associated factors among Human immunodeficiency virus positive patients accessing treatment at Nekemte referral hospital, west Ethiopia, 2019]]> https://www.researchpad.co/article/elastic_article_7637 Antiretroviral therapy has a remarkable clinical effect in reducing the progress of Acquired Immune Deficiency Syndrome. The clinical outcome of Anti-Retroviral therapy depends on strict adherence. Poor adherence reduces the effectiveness of antiretroviral therapy and increases viral replication. With changes in service delivery over time and differences in socio-demographic status from region to region, it is essential to measure adherence. Therefore, this study aimed to assess adherence to antiretroviral therapy and its associated factors among HIV/AIDS patients accessing treatment at Nekemte referral hospital, West Ethiopia.MethodsInstitutional based cross-sectional study was conducted on 311 HIV/AIDS patients from March 01 to March 30, 2019. The study participants were selected by a simple random sampling method and interviewed using structured questionnaires. Bivariable logistic regression was conducted to find an association between each independent variable and adherence to antiretroviral medication. Multivariable logistic regression was used to find the independent variables which best predict adherence. The statistical significance was measured using odds ratio at a 95% confidence interval with a p-value of less than 0.05.ResultsOut of a total of 311 patients sampled, 305 were participated in the study, making a response rate of 98.07%. From these 305 study participants,73.1% (95% CI = 68.2, 78.0) were adherent to their medication. Having knowledge about HIV and its treatment (AOR = 8.24, 95% CI: 3.10, 21.92), having strong family/social support (AOR = 6.21, 95% CI: 1.39, 27.62), absence of adverse drug reaction (AOR = 5.33, 95% CI: 1.95, 14.57), absence of comorbidity of other chronic diseases (AOR = 5.72, 95% CI: 1.91, 17.16) and disclosing HIV status to the family (AOR = 5.08, 95% CI: 2.09, 12.34) were significantly associated with an increased likelihood of adherence to antiretroviral medication.ConclusionThe level of adherence to antiretroviral therapy was found low compared to WHO recommendation. The clinician should emphasize reducing adverse drug reaction, detecting and treating co-morbidities early, improving knowledge through health education, and encouraging the patients to disclose their HIV status to their families. ]]> <![CDATA[Chitosan-propolis nanoparticle formulation demonstrates anti-bacterial activity against Enterococcus faecalis biofilms]]> https://www.researchpad.co/article/5989db50ab0ee8fa60bdc122

Propolis obtained from bee hives is a natural substance with antimicrobial properties. It is limited by its insolubility in aqueous solutions; hence ethanol and ethyl acetate extracts of Malaysian propolis were prepared. Both the extracts displayed antimicrobial and anti-biofilm properties against Enterococcus faecalis, a common bacterium associated with hospital-acquired infections. High performance liquid chromatography (HPLC) analysis of propolis revealed the presence of flavonoids like kaempferol and pinocembrin. This study investigated the role of propolis developed into nanoparticles with chitosan for its antimicrobial and anti-biofilm properties against E. faecalis. Bacteria that grow in a slimy layer of biofilm are resistant to penetration by antibacterial agents. The use of nanoparticles in medicine has received attention recently due to better bioavailability, enhanced penetrative capacity and improved efficacy. A chitosan-propolis nanoformulation was chosen based on ideal physicochemical properties such as particle size, zeta potential, polydispersity index, encapsulation efficiency and the rate of release of the active ingredients. This formulation inhibited E. faecalis biofilm formation and reduced the number of bacteria in the biofilm by ~90% at 200 μg/ml concentration. When tested on pre-formed biofilms, the formulation reduced bacterial number in the biofilm by ~40% and ~75% at 200 and 300 μg/ml, respectively. The formulation not only reduced bacterial numbers, but also physically disrupted the biofilm structure as observed by scanning electron microscopy. Treatment of biofilms with chitosan-propolis nanoparticles altered the expression of biofilm-associated genes in E. faecalis. The results of this study revealed that chitosan-propolis nanoformulation can be deemed as a potential anti-biofilm agent in resisting infections involving biofilm formation like chronic wounds and surgical site infections.

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<![CDATA[Streptococcal H2O2 inhibits IgE-triggered degranulation of RBL-2H3 mast cell/basophil cell line by inducing cell death]]> https://www.researchpad.co/article/Nadf2e0c3-9608-4100-a6fa-f03310d30959

Mast cells and basophils are central players in allergic reactions triggered by immunoglobulin E (IgE). They have intracellular granules containing allergic mediators (e.g., histamine, serotonin, inflammatory cytokines, proteases and β-hexosaminidase), and stimulation by IgE-allergen complex leads to the release of such allergic mediators from the granules, that is, degranulation. Mast cells are residents of mucosal surfaces, including those of nasal and oral cavities, and play an important role in the innate defense system. Members of the mitis group streptococci such as Streptococcus oralis, are primary colonizers of the human oral cavity. They produce hydrogen peroxide (H2O2) as a by-product of sugar metabolism. In this study, we investigated the effects of streptococcal infection on RBL-2H3 mast cell/basophil cell line. Infection by oral streptococci did not induce degranulation of the cells. Stimulation of the RBL-2H3 cells with anti-dinitrophenol (DNP) IgE and DNP-conjugated human serum albumin triggers degranulation with the release of β-hexosaminidase. We found that S. oralis and other mitis group streptococci inhibited the IgE-triggered degranulation of RBL-2H3 cells. Since mitis group streptococci produce H2O2, we examined the effect of S. oralis mutant strain deficient in producing H2O2, and found that they lost the ability to suppress the degranulation. Moreover, H2O2 alone inhibited the IgE-induced degranulation. Subsequent analysis suggested that the inhibition of degranulation was related to the cytotoxicity of streptococcal H2O2. Activated RBL-2H3 cells produce interleukin-4 (IL-4); however, IL-4 production was not induced by streptococcal H2O2. Furthermore, an in vivo study using the murine pollen-induced allergic rhinitis model suggested that the streptococcal H2O2 reduces nasal allergic reaction. These findings reveal that H2O2 produced by oral mitis group streptococci inhibits IgE-stimulated degranulation by inducing cell death. Consequently, streptococcal H2O2 can be considered to modulate the allergic reaction in mucosal surfaces.

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<![CDATA[Baloxavir treatment of ferrets infected with influenza A(H1N1)pdm09 virus reduces onward transmission]]> https://www.researchpad.co/article/Nca8f7add-a1d9-4373-9c77-344aec55ea94

Influenza viruses cause seasonal outbreaks and pose a continuous pandemic threat. Although vaccines are available for influenza control, their efficacy varies each season and a vaccine for a novel pandemic virus manufactured using current technology will not be available fast enough to mitigate the effect of the first pandemic wave. Antivirals can be effective against many different influenza viruses but have not thus far been used extensively for outbreak control. Baloxavir, a recently licensed antiviral drug that targets the influenza virus endonuclease, has been shown to reduce virus shedding more effectively than oseltamivir, a widely used neuraminidase inhibitor drug. Thus it is possible that treatment with baloxavir might also interrupt onward virus transmission. To test this, we utilized the ferret model, which is the most commonly used animal model to study influenza virus transmission. We established a subcutaneous baloxavir administration method in ferrets which achieved similar pharmacokinetics to the approved human oral dose. Transmission studies were then conducted in two different locations with different experimental setups to compare the onward transmission of A(H1N1)pdm09 virus from infected ferrets treated with baloxavir, oseltamivir or placebo to naïve sentinel ferrets exposed either indirectly in adjacent cages or directly by co-housing. We found that baloxavir treatment reduced infectious viral shedding in the upper respiratory tract of ferrets compared to placebo, and reduced the frequency of transmission amongst sentinels in both experimental setups, even when treatment was delayed until 2 days post-infection. In contrast, oseltamivir treatment did not substantially affect viral shedding or transmission compared to placebo. We did not detect the emergence of baloxavir-resistant variants in treated animals or in untreated sentinels. Our results support the concept that antivirals which decrease viral shedding could also reduce influenza transmission in the community.

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<![CDATA[Nosocomial transmission of extensively drug resistant Acinetobacter baumannii strains in a tertiary level hospital]]> https://www.researchpad.co/article/N9f3b656c-39ce-49ef-bced-db8369f1110d

Acinetobacter baumannii is an opportunistic infectious agent that affects primarily immunocompromised individuals. A. baumannii is highly prevalent in hospital settings being commonly associated with nosocomial transmission and drug resistance. Here, we report the identification and genetic characterization of A. baumannii strains among patients in a tertiary level hospital in Mexico. Whole genome sequencing analysis was performed to establish their genetic relationship and drug resistance mutations profile. Ten genetically different, extensively drug resistant strains were identified circulating among seven wards. The genetic profiles showed resistance primarily against aminoglycosides and beta-lactam antibiotics. Importantly, no mutants conferring resistance to colistin were observed. The results highlight the importance of implementing robust classification schemes for advanced genetic characterization of A. baumannii clinical isolates and simultaneous detection of drug resistance markers for adequate patient’s management in clinical settings.

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<![CDATA[Antibiotic use for Australian Aboriginal children in three remote Northern Territory communities]]> https://www.researchpad.co/article/N999fa4e6-a15c-456a-862e-2e1ce88316a9

Objective

To describe antibiotic prescription rates for Australian Aboriginal children aged <2 years living in three remote Northern Territory communities.

Design

A retrospective cohort study using electronic health records.

Setting

Three primary health care centres located in the Katherine East region.

Participants

Consent was obtained from 149 mothers to extract data from 196 child records. There were 124 children born between January 2010 and July 2014 who resided in one of the three chosen communities and had electronic health records for their first two years of life.

Main outcome measures

Antibiotic prescription rates, factors associated with antibiotic prescription and factors associated with appropriate antibiotic prescription.

Results

There were 5,675 Primary Health Care (PHC) encounters for 124 children (median 41, IQR 25.5, 64). Of the 5,675 PHC encounters, 1,542 (27%) recorded at least one infection (total 1,777) and 1,330 (23%) had at least one antibiotic prescription recorded (total 1,468). Children had a median five (IQR 2, 9) prescriptions in both their first and second year of life, with a prescription rate of 5.99/person year (95% CI 5.35, 6.63). Acute otitis media was the most common infection (683 records, 38%) and Amoxycillin was the most commonly prescribed antibiotic (797 prescriptions, 54%). Of the 1,468 recorded prescriptions, 398 (27%) had no infection recorded and 116 (8%) with an infection recorded were not aligned with local treatment guidelines.

Conclusion

Prescription rates for Australian Aboriginal children in these communities are significantly higher than that reported nationally for non-Aboriginal Australians. Prescriptions predominantly aligned with treatment guidelines in this setting where there is a high burden of infectious disease.

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<![CDATA[Potential combinations of endocannabinoid/endocannabinoid-like compounds and antibiotics against methicillin-resistant Staphylococcus aureus]]> https://www.researchpad.co/article/Ne8a72c2e-13c7-43d3-9f49-0ed6410d9d0b

Infections caused by antibiotic-resistant strains of Staphylococcus aureus have reached epidemic proportions globally. Our previous study showed antimicrobial effects of anandamide (AEA) and arachidonoyl serine (AraS) against methicillin (MET)-resistant S. aureus (MRSA) strains, proposing the therapeutic potential of these endocannabinoid/endocannabinoid-like (EC/EC-like) agents for the treatment of MRSA. Here, we investigated the potential synergism of combinations of AEA and AraS with different types of antibiotics against MRSA grown under planktonic growth or biofilm formation. The most effective combinations under planktonic conditions were mixtures of AEA and ampicillin (AMP), and of AraS and gentamicin (GEN). The combination with the highest synergy in the biofilm formation against all tested bacterial strains was AEA and MET. Moreover, the combination of AraS and MET synergistically caused default of biofilm formation. Slime production of MRSA was also dramatically impaired by AEA or AraS combined with MET. Our data suggest the novel potential activity of combinations of EC/EC-like agents and antibiotics in the prevention of MRSA biofilm formation.

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<![CDATA[Towards understanding the antagonistic activity of phytic acid against common foodborne bacterial pathogens using a general linear model]]> https://www.researchpad.co/article/Nee28f4e6-a119-4233-a9a2-0c085b39343b

The increasing challenge of antibiotic resistance requires not only the discovery of new antibiotics, but also the development of new alternative approaches. Therefore, in the present study, we investigated for the first time the antibacterial potential of phytic acid (myo-inositol hexakisphosphate, IP6), a natural molecule that is ‘generally recognized as safe’ (FDA classification), against the proliferation of common foodborne bacterial pathogens such as Listeria monocytogenes, Staphylococcus aureus and Salmonella Typhimurium. Interestingly, compared to citric acid, IP6 was found to exhibit significantly greater inhibitory activity (P<0.05) against these pathogenic bacteria. The minimum inhibitory concentration of IP6 varied from 0.488 to 0.97 mg/ml for the Gram-positive bacteria that were tested, and was 0.244 mg/ml for the Gram-negative bacteria. Linear and general models were used to further explore the antibacterial effects of IP6. The developed models were validated using experimental growth data for L. monocytogenes, S. aureus and S. Typhimurium. Overall, the models were able to accurately predict the growth of L. monocytogenes, S. aureus, and S. Typhimuriumin Polymyxin acriflavine lithium chloride ceftazidime aesculin mannitol (PALCAM), Chapman broth, and xylose lysine xeoxycholate (XLD) broth, respectively. Remarkably, the early logarithmic growth phase of S. Typhimurium showed a rapid and severe decrease in a period of less than one hour, illustrating the bactericidal effect of IP6. These results suggest that IP6 is an efficient antibacterial agent and can be used to control the proliferation of foodborne pathogens. It has promising potential for environmentally friendly applications in the food industry, such as for food preservation, food safety, and for prolonging shelf life.

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<![CDATA[Evaluation of liposomal ciprofloxacin formulations in a murine model of anthrax]]> https://www.researchpad.co/article/Ne17111d7-5152-4c88-81b1-0e84a1b58e42

The in vivo efficacy of liposomal encapsulated ciprofloxacin in two formulations, lipoquin and apulmiq, were evaluated against the causative agent of anthrax, Bacillus anthracis. Liposomal encapsulated ciprofloxacin is attractive as a therapy since it allows for once daily dosing and achieves higher concentrations of the antibiotic at the site of initial mucosal entry but lower systemic drug concentrations. The in vivo efficacy of lipoquin and apulmiq delivered by intranasal instillation was studied at different doses and schedules in both a post exposure prophylaxis (PEP) therapy model and in a delayed treatment model of murine inhalational anthrax. In the mouse model of infection, the survival curves for all treatment cohorts differed significantly from the vehicle control. Ciprofloxacin, lipoquin and apulmiq provided a high level of protection (87–90%) after 7 days of therapy when administered within 24 hours of exposure. Reducing therapy to only three days still provided protection of 60–87%, if therapy was provided within 24 hours of exposure. If treatment was initiated 48 hours after exposure the survival rate was reduced to 46–65%. These studies suggest that lipoquin and apulmiq may be attractive therapies as PEP and as part of a treatment cocktail for B. anthracis.

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<![CDATA[The evolution and genetic diversity of avian influenza A(H9N2) viruses in Cambodia, 2015 – 2016]]> https://www.researchpad.co/article/Ncf402c92-86f9-4684-b431-03c7c64bd7da

Low pathogenic A(H9N2) subtype avian influenza viruses (AIVs) were originally detected in Cambodian poultry in 2013, and now circulate endemically. We sequenced and characterised 64 A(H9N2) AIVs detected in Cambodian poultry (chickens and ducks) from January 2015 to May 2016. All A(H9) viruses collected in 2015 and 2016 belonged to a new BJ/94-like h9-4.2.5 sub-lineage that emerged in the region during or after 2013, and was distinct to previously detected Cambodian viruses. Overall, there was a reduction of genetic diversity of H9N2 since 2013, however two genotypes were detected in circulation, P and V, with extensive reassortment between the viruses. Phylogenetic analysis showed a close relationship between A(H9N2) AIVs detected in Cambodian and Vietnamese poultry, highlighting cross-border trade/movement of live, domestic poultry between the countries. Wild birds may also play a role in A(H9N2) transmission in the region. Some genes of the Cambodian isolates frequently clustered with zoonotic A(H7N9), A(H9N2) and A(H10N8) viruses, suggesting a common ecology. Molecular analysis showed 100% of viruses contained the hemagglutinin (HA) Q226L substitution, which favours mammalian receptor type binding. All viruses were susceptible to the neuraminidase inhibitor antivirals; however, 41% contained the matrix (M2) S31N substitution associated with resistance to adamantanes. Overall, Cambodian A(H9N2) viruses possessed factors known to increase zoonotic potential, and therefore their evolution should be continually monitored.

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<![CDATA[Quantitative dynamics of Salmonella and E. coli in feces of feedlot cattle treated with ceftiofur and chlortetracycline]]> https://www.researchpad.co/article/Nd45d35d0-8623-4716-b387-5e4fac70c4ad

Antibiotic use in beef cattle is a risk factor for the expansion of antimicrobial-resistant Salmonella populations. However, actual changes in the quantity of Salmonella in cattle feces following antibiotic use have not been investigated. Previously, we observed an overall reduction in Salmonella prevalence in cattle feces associated with both ceftiofur crystalline-free acid (CCFA) and chlortetracycline (CTC) use; however, during the same time frame the prevalence of multidrug-resistant Salmonella increased. The purpose of this analysis was to quantify the dynamics of Salmonella using colony counting (via a spiral-plating method) and hydrolysis probe-based qPCR (TaqMan® qPCR). Additionally, we quantified antibiotic-resistant Salmonella by plating to agar containing antibiotics at Clinical & Laboratory Standards Institute breakpoint concentrations. Cattle were randomly assigned to 4 treatment groups across 16 pens in 2 replicates consisting of 88 cattle each. Fecal samples from Days 0, 4, 8, 14, 20, and 26 were subjected to quantification assays. Duplicate qPCR assays targeting the Salmonella invA gene were performed on total community DNA for 1,040 samples. Diluted fecal samples were spiral plated on plain Brilliant Green Agar (BGA) and BGA with ceftriaxone (4 μg/ml) or tetracycline (16 μg/ml). For comparison purposes, indicator non-type-specific (NTS) E. coli were also quantified by direct spiral plating. Quantity of NTS E. coli and Salmonella significantly decreased immediately following CCFA treatment. CTC treatment further decreased the quantity of Salmonella but not NTS E. coli. Effects of antibiotics on the imputed log10 quantity of Salmonella were analyzed via a multi-level mixed linear regression model. The invA gene copies decreased with CCFA treatment by approximately 2 log10 gene copies/g feces and remained low following additional CTC treatment. The quantities of tetracycline or ceftriaxone-resistant Salmonella were approximately 4 log10 CFU/g feces; however, most of the samples were under the quantification limit. The results of this study demonstrate that antibiotic use decreases the overall quantity of Salmonella in cattle feces in the short term; however, the overall quantities of antimicrobial-resistant NTS E. coli and Salmonella tend to remain at a constant level throughout.

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<![CDATA[Graphene oxide in zinc alginate films: Antibacterial activity, cytotoxicity, zinc release, water sorption/diffusion, wettability and opacity]]> https://www.researchpad.co/article/5c990314d5eed0c484b98c1a

Alginate is considered an exceptional biomaterial due to its hydrophilicity, biocompatibility, biodegradability, nontoxicity and low-cost in comparison with other biopolymers. We have recently demonstrated that the incorporation of 1% graphene oxide (GO) into alginate films crosslinked with Ca2+ cations provides antibacterial activity against Staphylococcus aureus and methicillin-resistant Staphylococcus epidermidis, and no cytotoxicity for human keratinocyte HaCaT cells. However, many other reports in literature have shown controversial results about the toxicity of GO demanding further investigation. Furthermore, the synergic effect of GO with other divalent cations with intrinsic antibacterial and cytotoxic activity such as Zn2+ has not been explored yet. Thus, here, two commercially available sodium alginates were characterised and utilized in the synthesis of zinc alginate films with GO following the same chemical route reported for the calcium alginate/GO composites. The results of this study showed that zinc release, water sorption/diffusion and wettability depended significantly on the type of alginate utilized. Furthermore, Zn2+ and GO produced alginate films with increased water diffusion, wettability and opacity. However, neither the combination of GO with Zn2+ nor the use of different types of sodium alginates modified the antibacterial activity and cytotoxicity of the zinc alginates against these Gram-positive pathogens and human cells respectively.

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<![CDATA[Candida lusitaniae in Kuwait: Prevalence, antifungal susceptibility and role in neonatal fungemia]]> https://www.researchpad.co/article/5c8accced5eed0c484990063

Objectives

Candida lusitaniae is an opportunistic yeast pathogen in certain high-risk patient populations/cohorts. The species exhibits an unusual antifungal susceptibility profile with tendency to acquire rapid resistance. Here, we describe prevalence of C. lusitaniae in clinical specimens in Kuwait, its antifungal susceptibility profile and role in neonatal fungemia.

Methods

Clinical C. lusitaniae isolates recovered from diverse specimens during 2011 to 2017 were retrospectively analyzed. All isolates were identified by germ tube test, growth on CHROMagar Candida and by Vitek 2 yeast identification system. A simple species-specific PCR assay was developed and results were confirmed by PCR-sequencing of ITS region of rDNA. Antifungal susceptibility was determined by Etest. Minimum inhibitory concentrations (MICs) were recorded after 24 h incubation at 35°C.

Results

Of 7068 yeast isolates, 134 (1.89%) were identified as C. lusitaniae including 25 (2.52%) among 990 bloodstream isolates. Species-specific PCR and PCR-sequencing of rDNA confirmed identification. Of 11 cases of neonatal candidemia, 9 occurred in NICU of Hospital A and are described here. Eight of 9 neonates received liposomal amphotericin B, which was followed by fluconazole in 7 and additionally by caspofungin in 2 cases as salvage therapy. Three of 8 (37.5%) patients died. No isolate exhibited reduced susceptibility to amphotericin B, fluconazole, voriconazole, caspopfungin, micafungin and anidulafungin. The MIC ± geometric mean values for amphotericin B, fluconazole, voriconazole, and caspofungin were as follows: 0.072 ± 0.037 μg/ml, 2.32 ± 0.49 μg/ml, 0.09 ± 0.01 μg/ml and 0.16 ± 0.08 μg/ml, respectively. Only two isolates exhibited reduced susceptibility to fluconazole.

Conclusions

This study describes the prevalence and antifungal susceptibility profile of clinical C. lusitaniae isolates in Kuwait. No isolate showed reduced susceptibility to amphotericin B. The study highlights the emerging role of C. lusitaniae as a healthcare-associated pathogen capable of causing fungemia in preterm neonates and causing significant mortality.

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