Acinetobacter Lwoffii Research Articles

Ecological Structure of the Public Transportation Microbiocoenosis

The microbiological patterns of the passenger cabins of urban public transportation by the example of 41 buses from 16 routes was described for the first time. According to orographic features of the city of Nizhny Novgorod, all the bus routes were divided into three model groups designated as “High-bank,” “Low-bank,” and “Interdistrict.” The abundance of microorganisms and the species composition were estimated using an Autoflex MALDI mass spectrometer (Bruker Daltonics, Germany) and the BioTyper software. In the samples collected, 85 microbial species were detected, identified, and assigned to one of the following three groups according to their degree of pathogenicity: (1) opportunistic pathogens often causing infectious diseases; (2) opportunistic pathogens rarely causing infectious diseases, and (3) nonpathogenic microorganisms. To characterize the ecological structure of the microbial community of urban public transport, two similarity indices for the microbiocoenoses studied, the Sorensen binary index and the multidimensional Koch biotic dispersion index, were calculated. The species composition was analyzed at two hierarchical levels of the bus route groups (the intragroup and intergroup ones). At the intragroup level, a small number (1–3) of common species represented by Staphylococcus epidermidis, S. haemolyticus, and Acinetobacter lwoffii were found in each route group, which corresponds to a low Koch index value (0.1). At the intergroup level, 15 common species of microorganisms were found, which corresponds to the value of the Koch index calculated for the three route groups (0.26), i.e., 26% of species were common for the three route groups analyzed. Species of three groups of microorganisms were most comprehensively represented in the “Interdistrict” group: 45% species of Group 1, 53.8% species of Group 2, and 58.1% species of Group 3. Community structure analysis carried out using ecological indices (Shannon species diversity index, Simpson index of dominance, Margalef species richness index, and Pielou species evenness index) showed that an increase in the species diversity of microbial communities was accompanied by a regular decrease in dominance and an increase in evenness. Analysis of the group of dominant species identified in the buses of the three route groups revealed that the species similarity of the dominant species, estimated by the value of the Koch index, was only 0.14, which could be explained by the presence of only one common species (Acinetobacter lwoffii). Studies of the microbial community of urban transportation present a perspective for solving the sanitary, hygienic, and environmental aspects of the integrated problem of ensuring the ecological safety of the urban environment.

Clinical Evaluation a New Treatment for Infection After Ventriculoperitoneal Shunt.

To explore a new surgical treatment for infection and obstruction of ventriculoperitoneal shunt in hydrocephalus. Two cases of post-operative infection of ventriculoperitoneal shunt were analyzed retrospectively. One case was cryptococcal infection, the other case was Acinetobacter lwoffii. The number of cerebrospinal fluid cells was high, the infection of ventriculoperitoneal shunt was generally complicated with abdominal obstruction, and the hydrocephalus was aggravated again, The authors try to pull out the drainage tube at the end of abdominal cavity for external drainage, combined with intravenous antibiotics, completely control of infection, and then use the original shunt device for intraventricular jugular shunt. The authors explore that this method is simple, safe and effective, and it is an effective and feasible method for the treatment of infection after ventriculoperitoneal shunt.

Acinetobacter Plasmids: Diversity and Development of Classification Strategies.

Bacteria of the genus Acinetobacter, with their numerous species common in various habitats, play a significant role as pathogens. Their ability to adapt to different living conditions is largely due to the presence of numerous plasmids containing the necessary adaptive genes. At the same time the diversity of Acinetobacter plasmids and their evolutionary dynamics have not been sufficiently studied. Here, we characterized 44 plasmids isolated from five permafrost Acinetobacter lwoffii strains, examined their relationship with plasmids of modern Acinetobacter strains and identified groups of related plasmids. For this purpose, we have developed a combined approach for classifying all known Acinetobacter plasmids. The classification took into account the size of plasmids, the presence and structure of the rep and mob genes, as well as the structure of their backbone and accessory regions. Based on the analysis, 19 major groups (lineages) of plasmids were identified, of which more than half were small plasmids. The plasmids of each group have common features of the organization of the backbone region with a DNA identity level of at least 80%. In addition, plasmids of the same group have similarities in the organization of accessory regions. We also described a number of plasmids with a unique structure. The presence of plasmids in clinical strains that are closely related to those of environmental permafrost strains provides evidence of the origin of the former from the latter.

Decolorization, degradation and detoxification of carcinogenic sulfonated azo dye methyl orange by newly developed biofilm consortia.

Metabolites of azo dyes are often carcinogenic, teratogenic, mutagenic and recalcitrant in nature. In this study, four biofilm consortia such as C1 (Vitreoscilla sp. ENSG301, Acinetobacter lwoffii ENSG302, Klebsiella pneumoniae ENSG303 and Pseudomonas fluorescens ENSG304), C2 (Escherichia coli ENSD101, Enterobacter asburiae ENSD102 and E. ludwigii ENSH201), C3 (E. asburiae ENSD102, Vitreoscilla sp. ENSG301 and Bacillus thuringiensis ENSW401), and C4 (E. coli ENSD101, E. ludwigii ENSH201 and B. thuringiensis ENSW401) were applied to degrade and detoxify methyl orange (MO), a carcinogenic, sulfonated mono azo dye, used in textile dyeing industry worldwide. The consortia of C1, C2, C3 and C4 showed 97.30, 98.75, 99.51 and 99.29% decolorization, respectively in yeast extract peptone (YEP) broth containing 200 mg L−1 MO within 60 h of incubation in static condition. The optimum pH and temperature for decolorization was 7.0 and 28 °C, respectively. Some divalent metal ions including Mg2+, Ca2+, Zn2+ and Mn2+ could stimulate MO decolorization. UV–Vis spectral analysis showed that the absorption peak at 465 nm originated from the azo (N Created by potrace 1.16, written by Peter Selinger 2001-2019 ]]> N) bond was completely disappeared within 60 h of incubation. Fourier transform infrared spectroscopy (FTIR) results also revealed that several major peaks including azo bond peak at 1602.6 cm−1 are completely or partly vanished, deformed or shifted. Activities of azoreductase, NADH-DCIP reductase and laccase were significantly increased in the bacterial cells within 60 h of incubation in comparison to that of control (0 h). The chemical oxygen demand was incredibly reduced by 85.37 to 91.44% by these consortia. Accordingly, plant (wheat seed germination) and microbial (growth of the plant probiotic bacteria such as Pseudomonas cedrina ESR12 and Bacillus cereus ESD3 on biodegraded products) toxicity studies showed that biodegraded products of MO are non-toxic. Thus, all these consortia can be utilized in bioremediation of MO from wastewater for safe disposal into environment. To our knowledge, this is the first report on degradation and detoxification of MO from wastewater by bacterial biofilm consortia.

Evaluation of bacterial contamination and mutagenic potential of treated wastewater from Al-Samra wastewater treatment plant in Jordan.

Jordan is one of the lowest countries in the world in terms of water resources. The reuse of treated wastewater is an important alternative to supply agricultural demands for water. In Jordan, Kherbet Al-Samra wastewater treatment plant (KSWWTP) is the largest and its effluent is mainly used for irrigation purposes. In this study, bacterial contamination and mutagenic potential were evaluated in six sites, beginning with KSWWTP and ending with King Tallal Dam. The results showed high contamination with many pathogenic bacteria and coliforms. The isolated pathogenic bacteria were Salmonella sp., Shigella sp., Bacillus cereus and Staphylococcus aureus. The isolated opportunistic pathogenic bacteria were Acinetobacter lwoffii, Elizabethkingia meningosepticum, Pseudomonas fluorescens and Bacillus licheniformis. These bacteria were found in all sampling sites without a specific prevalence pattern. Differences in temperature between seasons affect total coliform and other bacterial count. All water samples showed positive mutagenic activity and high bacterial pollution. Improving the disinfection efficiency in the wastewater treatment plant is important to minimize potential toxicity and exposure of public health to pathogenic bacteria, reduce water resources' contamination and environmental pollution. Increasing effluent sampling frequency from KSWWTP is required to monitor bacterial contamination and toxicity/mutagenicity level for water safety and public health risk assessments.

Gut Fecal Microbiota Transplant in a Mouse Model of Orthotopic Rectal Cancer.

The gut microbiota is reported to play an important role in carcinogenesis and the treatment of CRC. SW480 and SW620 colon cancer cells integrated with infrared fluorescent proteins were injected into the rectal submucosa of nude mice. In the subsequent 30 days, we observed tumor growth weekly using an in vivo imaging system. The bacterial solution was infused anally into the mice to perform bacterial transplant. Phosphate-buffered saline, Acinetobacter lwoffii, and Bifidobacterium longum solutions were infused individually. The 16S ribosomal DNA (rDNA) and polymerase chain reaction of murine feces were investigated to confirm the colonization of target bacteria. In the SW620 orthotopic xenograft rectal cancer model, 4 of 5 mice developed rectal cancer by 30 days after submucosal injection. In the SW480 orthotopic xenograft rectal cancer model, 2 of 6 mice developed rectal cancer by 30 days after submucosal injection. For the 16S rDNA analysis, the mice receiving the bacterial solution infusion demonstrated positive findings for A. lwoffii and B. longum. With the successful establishment of a mouse model of orthotopic rectal cancer and transplant of target bacteria, we can further explore the relationship between gut microbiota and CRC. The role of fecal microbiota transplant in the treatment and alleviation of adverse events of chemotherapy in CRC could be clarified in subsequent studies.

Comparison of Bacterial Microbiota in Raw Mare's Milk and Koumiss Using PacBio Single Molecule Real-Time Sequencing Technology.

Koumiss is a traditional fermented raw mare’s milk product. It contains high nutritional value and is well-known for its health-promoting effect as an alimentary supplement. This study aimed to investigate the bacterial diversity, especially lactic acid bacteria (LAB), in koumiss and raw mare’s milk. Forty-two samples, including koumiss and raw mare’s milk, were collected from the pastoral area in Yili, Kazakh Autonomous Prefecture, Xinjiang Uygur Autonomous Region in China. This work applied PacBio single-molecule real-time (SMRT) sequencing to profile full-length 16S rRNA genes, which was a powerful technology enabling bacterial taxonomic assignment to the species precision. The SMRT sequencing identified 12 phyla, 124 genera, and 227 species across 29 koumiss samples. Eighteen phyla, 286 genera, and 491 species were found across 13 raw mare’s milk samples. The bacterial microbiota diversity of the raw mare’s milk was more complex and diverse than the koumiss. Raw mare’s milk was rich in LAB, such as Lactobacillus (L.) helveticus, L. plantarum, Lactococcus (Lc.) lactis, and L. kefiranofaciens. In addition, raw mare’s milk also contained sequences representing pathogenic bacteria, such as Staphylococcus succinus, Acinetobacter lwoffii, Klebsiella (K.) oxytoca, and K. pneumoniae. The koumiss microbiota mainly comprised LAB, and sequences representing pathogenic bacteria were not detected. Meanwhile, the koumiss was enriched with secondary metabolic pathways that were potentially beneficial for health. Using a Random Forest model, the two kinds of samples could be distinguished with a high accuracy 95.2% [area under the curve (AUC) = 0.98] based on 42 species and functions. Comprehensive depiction of the microbiota in raw mare’s milk and koumiss might help elucidate evolutionary and functional relationships among the bacterial communities in these dairy products. The current work suffered from the limitation of a low sample size, so further work would be required to verify our findings.

Novel bacterial biofilm consortia that degrade and detoxify the carcinogenic diazo dye Congo red.

Free-living planktonic single bacterial strain can decolorize Congo red (CR) but often produces the carcinogenic, mutagenic and genotoxic aromatic amines. Planktonic single and bacterial consortia are more susceptible to toxic pollutants than their biofilm counterparts. In the present study, four biofilm consortia (C1 = Vitreoscilla sp. ENSG301, Acinetobacter lwoffii ENSG302, Klebsiella pneumoniae ENSG303 and Pseudomonas fluorescens ENSG304, C2 = Escherichia coli ENSD101, Enterobacter asburiae ENSD102 and E. ludwigii ENSH201, C3 = E. asburiae ENSD102, Vitreoscilla sp. ENSG301 and Bacillus thuringiensis ENSW401, and C4 = E. coli ENSD101, E. ludwigii ENSH201 and B. thuringiensis ENSW401) were prepared and assessed for bioremediation of CR. All these biofilm consortia remarkably decolorized (96.9 to 99.5%) the CR (100mg/L) in static condition within 72h incubation at 28°C. These consortia also synthesized significantly more intracellular azoreductase and laccase enzyme than extracellular of these enzymes. UV-Vis spectral analysis revealed that the major peak at 478nm wavelength of CR was completely disappeared. FTIR analysis showed several major peaks along with azo bonds are completely or partly disappeared, deformed or widened. Chemical oxygen demand was reduced by 86.4, 85.5, 87.0 and 86.2% by C1, C2, C3 and C4, respectively. Accordingly, biodegraded metabolites of CR by different biofilm consortia did not inhibit the germination of wheat seeds and bacterial growth. Thus, these biofilm consortia can be applied in bioremediation of wastewater containing CR for safe disposal into the environment. To our knowledge, this is the first report on degradation and detoxification of aqueous solution containing CR by bacterial biofilm consortia.

Multifunctional potential of endophytic bacteria from Anacardium othonianum Rizzini in promoting in vitro and ex vitro plant growth

Anacardium othonianum Rizzini, a cashew tree native to the Brazilian Cerrado, is economically important due to its applications in the food, chemical and pharmaceutical industries. However, A. othonianum yields a crop with low productivity due to a number of factors, such as nutritionally poor soils, drought and losses due to pests and diseases. Brazil is one of the nine largest cashew nut producers worldwide, and sustainable technologies are needed to increase the productivity of this crop. In this context, the use of endophytic microorganisms could promote plant growth and provide protection against phytopathogens. In this study, the isolation of the root endophytic community of A. othonianum led to the characterization of 22 distinct bacterial strains with multifunctional traits for plant growth promotion. The results of in vitro assays to assess auxin synthesis, phosphate solubilization, phosphatase and siderophore production and biocontrol against Fusarium oxysporum led to the selection of Acinetobacter lwoffii Bac109 and Pantoea agglomerans Bac131 as the most promising strains. The reinoculation of the Bac109 and Bac131 strains onto A. othonianum seeds showed that the treatment containing a mixture of these strains was the most effective in promoting increases in the biometric parameters of early plant growth. Thus, this study highlights the biotechnological potential of a consortium of A. lwoffii Bac109 and P. agglomerans Bac131 for future applications in sustainable cashew cultivation.

Antibiotic resistance mechanisms in Acinetobacter spp. strains isolated from patients in a paediatric hospital in Mexico

ObjectivesThe aim of this study was to identify Acinetobacter spp. strains from paediatric patients, to determine their genetic relationship, to detect antibiotic resistance genes and to evaluate the role of efflux pumps in antibiotic resistance. MethodsA total of 54 non-duplicate, non-consecutive Acinetobacter spp. isolates were collected from paediatric patients. Their genetic relationship, antibiotic resistance profile, efflux pump activity, antibiotic resistance genes and plasmid profile were determined. ResultsThe isolates were identified as 24 Acinetobacter haemolyticus, 24 Acinetobacter calcoaceticus–baumannii (Acb) complex and 1 strain each of Acinetobacter junii, Acinetobacter radioresistens, Acinetobacter indicus, Acinetobacter lwoffii, Acinetobacter ursingii and Acinetobacter venetianus. The 24 A. haemolyticus were considered genetically unrelated. One strain was resistant to carbapenems, two to cephalosporins, two to ciprofloxacin and sixteen to aminoglycosides. The antibiotic resistance genes blaOXA-214 (29%), blaOXA-215 (4%), blaOXA-264 (8%), blaOXA-265 (29%), blaNDM-1 (4%), aac(6ʹ)-Ig (38%) and the novel variants blaOXA-575 (13%), blaTEM-229 (75%), aac(6ʹ)-Iga (4%), aac(6ʹ)-Igb (13%) and aac(6ʹ)-Igc (42%) were detected. Among 24 Acb complex, 5 were multidrug-resistant, carbapenem-resistant strains carrying blaOXA-51 and blaOXA-23; they were genetically related and had the same plasmid profile. Other species were susceptible. In some strains of A. haemolyticus and Acb complex, the role of RND efflux pumps was evidenced by a decrease in the MICs for cefotaxime, amikacin and ciprofloxacin in the presence of an efflux pump inhibitor. ConclusionsThis study identified isolates of A. haemolyticus carrying new β-lactamase variants and shows for the first time the contribution of efflux pumps to antibiotic resistance in this species.

Characterization of Ligninolytic Bacteria and Analysis of Alkali-Lignin Biodegradation Products.

Ligninolytic bacteria degrading lignin were isolates and identified, and their biodegradation mechanism of alkaline-lignin was investigated. Four strains with lignin degradation capability were screened and identified from the soil, straw, and silage based on their decolorizing capacity of aniline blue and colony size on alkaline-lignin medium. The degradation ratio of Bacillus aryabhattai BY5, Acinetobacter johnsonii LN2, Acinetobacter lwoffii LN4, and Micrococcus yunnanensis CL32 have been assayed using alkaline-lignin as the unique carbon source. Further, the Lip (lignin peroxidase) and Mnp (manganese peroxidase) activities of strains were investigated. Lip activity of A. lwoffii LN4 was highest after 72 h of incubation and reached 7151.7 U · l–1. Mnp activity of M. yunnanensis CL32 was highest after 48 h and reached 12533 U · l–1. The analysis of alkaline-lignin degradation products by GC-MS revealed that the strains screened could utilize aromatic esters compounds such as dibutyl phthalate (DBP), and decomposite monocyclic aromatic compounds through the DBP aerobic metabolic pathway. The results indicate that B. aryabhattai BY5, A. johnsonii LN2, A. lwoffii LN4, and M. yunnanensis CL32 have high potential to degrade alkaline-lignin, and might utilize aromatic compounds by DBP aerobic metabolic pathway in the process of lignin degradation.

A Novel Plasmid pALWVS1.4 from Acinetobacter lwoffii Strain VS15, Carrying the Chloramphenicol Resistance Gene

Sequencing and analysis of the genome of the chloramphenicol-resistant strain Acinetobacter lwoffii VS15, isolated from permafrost, revealed a circular plasmid 11 964 bp in length, designated pAL-WVS1.4. Apart from the genes supporting the plasmid maintenance and mobilization, pALWVS1.4 contains the cflA gene encoding the membrane protein of the MFS transporter family. Close homologues of cflA were found in bacteria of the genus Psychrobacter, but were absent in the Acinetobacter genomes. The cflA gene is flanked by two copies of IS elements of the IS4 family, indicating that it was acquired by A. lwoffii VS15 via horizontal transfer within this putative composite transposon. A recombinant Escherichia coli strain expressing CflA was obtained and it was shown that under conditions of induced expression, the strain was resistant to chloramphenicol.

Bacterial contamination of protective lead garments in an operating room setting.

Protective lead garments (PLG) worn in the operating room are a potential source for bacterial colonisation and thus may increase the risk of intraoperative infection. The clinical significance of such bacterial contamination has yet been established. Although disinfection protocols have been employed, their effectiveness is also unknown. We sought to describe and compare the bacterial profile of PLGs with a focus on common pathogens involved in surgical site infections (SSI) and prosthetic joint infections (PJI). We studied body aprons and neck-thyroid protective shields. We sampled 20 body aprons and 21 neck PLGs, swabbing the inside and outside of the PLGs. Swabs were cultured on different media and the results were assessed and compared. Of PLGs, 87.8% were contaminated. The neck-thyroid shield PLGs was generally more contaminated than body apron PLGs and exhibited significantly higher loads of Staphylococcus epidermidis (P = 0.048). Other pathogen cultured were Micrococcus spp., Acinetobacter lwoffii (A. lwoffii), Bacillus species (Bacillus spp.), Moraxella osloensis (M. osloensis) and Pseudomonas stutzeri (P. stutzeri). No other common pathogens associated with SSI or PJI were detected. PLGs are heavily contaminated despite regular cleaning protocols. Neck PLGs are highly contaminated with potentially infectious agents. As neck PLGs are often directly exposed above the surgical sterile gown and the surgical field, measures should be undertaken to reduce their exposure and bacterial load, perhaps by suggesting users consider avoiding the use of intraoperative fluoroscopy when possible or alternatively supporting the use of body exhaust suits when PLGs are needed.

Antagonistic bacteria for biospace control of roselle spot (Corynespora cassiicola) of Hibiscus sabdariffa

En años recientes, el manchado de la jamaica inducido por <em>Corynespora</em> <em>cassiicola</em> amenaza la producción de cálices. El objetivo fue determinar si algunas cepas bacterianas inhiben el desarrollo de <em>C. cassiicola in vitro</em> y bajo condiciones de bioespacio. La inhibición del desarrollo fue por confrontación dual de las bacterias: alimentos (20), piel de anfibios (41), jales mineros (22), aire (siete) y rizosfera (10) contra el hongo. Se sembraron plantas de jamaica variedad “criolla” y se inocularon artificialmente con <em>C. cassiicola</em>, a partir del inicio de síntomas de la enfermedad se inocularon las cepas bacterianas seleccionadas con mayor porcentaje de inhibición. Se evaluó la ABCPE. Solo siete cepas inhibieron del 62.7 al 100% el desarrollo del hongo <em>in vitro</em>: <em>Klebsiella pneumoniae</em> (M10-1 y M10-10), <em>Acinetobacter lwoffii</em> (A5), <em>Sphingomonas</em> <em>paucimobilis</em> (NF21), <em>Serratia marcescens</em> (M13ACD), <em>S. liquefaciens</em> (M8ACD) y <em>Acinetobacter</em> sp. (5H2). En relación a la severidad en hojas las cepas M10-1 y M10-10 redujeron el ABCPE en un 9.5 y 12.6%, respectivamente, seguido de NF21 (14.5 de ABCPE), el control registró los mayores niveles (45.7 de ABCPE). Para la severidad en cálices, los análisis del ABCPE de todas las cepas ejercieron control al reducir niveles de severidad (17.1-8.6 ABCPE).

Multidrug Resistant Acinetobacter Isolates Release Resistance Determinants Through Contact-Dependent Killing and Bacteriophage Lysis.

Antimicrobial resistance is an ancient bacterial defense mechanism that has rapidly spread due to the frequent use of antibiotics for disease treatment and livestock growth promotion. We are becoming increasingly aware that pathogens, such as members of the genus Acinetobacter, are precipitously evolving drug resistances through multiple mechanisms, including the acquisition of antibiotic resistance genes. In this study, we isolated three multidrug resistant Acinetobacter species from birds on a free-range farm. Acinetobacter radioresistens, Acinetobacter lwoffii, and Acinetobacter johnsonii were isolated from hens, turkeys and ducks and were resistant to 14 clinically relevant antibiotics, including several listed by the World Health Organization as essential medicines. Co-culturing any of the three Acinetobacter species with Acinetobacter baumannii resulted in contact-dependent release of intact resistance determinants. We also isolated several lytic bacteriophages and selected two of these phages to be included in this study based on differences in plaquing characteristics, nucleic acid content and viral morphology. Both phages released host DNA, including antibiotic resistance genes during cell lysis and we demonstrated that these resistance determinants were transferable to a naïve strain of Escherichia coli. This study demonstrates that contact-dependent competition between bacterial species can readily contribute to DNA release into the environment, including antibiotic resistance determinants. We also highlight that the constant lysis and turnover of bacterial populations during the natural lifecycle of a lytic bacteriophage is an underappreciated mechanism for the liberation of DNA and subsequent genetic exchange.

Acinetobacter mesopotamicus sp. nov., Petroleum-degrading Bacterium, Isolated from Petroleum-Contaminated Soil in Diyarbakir, in the Southeast of Turkey

A new petroleum-degrading bacterium, designated strain GC2T, was isolated from Bozkuş 1 petroleum station in Diyarbakir, located in the southeast of Turkey. Cells were Gram-negative staining, aerobic, coccoid-rods, non-motile, non-spore-forming. The bacterium was found to degrade 100% of n-alkanes ranging from C11 to C34 presented in the 1% crude oil after incubation of 7days. The membrane phospholipids were 1,2 diacylglycero-3-phosphorylethanolamine (PEA), phosphatidylglycerol (PG), dipalmitoyl-sn-glycerol 1- phosphocholine (PC1), 1,2 dipalmitoyl-sn-glycero-3-phosphocholine monohydrate (PC3), cardiolipin also called diphosphatidylglycerol (CL) and l-α- phosphatidic acid, dipalmitoyl (AP); predominant respiratory ubiquinone was Q-8 and C16:0, C18:1ω9c and C16:1 were the major cellular fatty acids. The 16S rRNA sequence analysis revealed that the strain GC2T was a member of genus Acinetobacter and was most closely related to Acinetobacter lwoffii DSM 2403T (99.79%), Acinetobacter pseudolwoffii ANC 5318T (98.83%) and Acinetobacter harbinensis HITLi 7T (98.14%). The rpoB and gyrB gene sequence analysis confirmed that the strain GC2T was a member of genus Acinetobacter and that the closest relative was Acinetobacter lwoffii DSM 2403T (99.08% and 100% similarity, respectively). DNA-DNA hybridization values between GC2T and its closest relatives ranged from 65.6% (with A. lwoffii) to 5.1% (with A. venetianus). Thewhole genome sequence of strain GC2T was obtained. The DNA G + C content of this strain was determined to be 42.9mol %. ANI indexes, in silico estimations of DDH values and wet lab DDH values demonstrated that strain GC2T represents an independent genomospecies. On the basis of phenotypic characteristics, chemotaxonomic, phylogenetic data and DNA-DNA hybridization and whole genome analysis, we propose to assign strain GC2T as a new species of the genus Acinetobacter, for which the name Acinetobacter mesopotamicus sp. nov. is proposed. The type strain of this species is GC2T (DSM 26953T = JCM 31073T). The whole genome of strain GC2T has been deposited at DDBJ/ENA/GenBank under the accession JAALFF010000000.

Curcumin, a Natural Antimicrobial Agent with Strain-Specific Activity.

Curcumin, a principal bioactive substance of turmeric (Curcuma longa L.), is reported as a strong antioxidant, anti-inflammatory, antibacterial, antifungal, and antiviral agent. However, its antimicrobial properties require further detailed investigations into clinical and multidrug-resistant (MDR) isolates. In this work, we tested curcumin’s efficacy against over 100 strains of pathogens belonging to 19 species. This activity was determined by the broth microdilution method and by calculating the minimum inhibitory concentration (MIC). Our findings confirmed a much greater sensitivity of Gram-positive than Gram-negative bacteria. This study exhibited a significantly larger variation in the curcumin activity than previous works and suggested that numerous clinical strains of widespread pathogens have a poor sensitivity to curcumin. Similarly, the MICs of the MDR types of Staphylococcus aureus, S. haemolyticus, Escherichia coli, and Proteus mirabilis were high (≥2000 µg/mL). However, curcumin was effective against some species and strains: Streptococcus pyogenes (median MIC = 31.25 µg/mL), methicillin-sensitive S. aureus (250 µg/mL), Acinetobacter lwoffii (250 µg/mL), and individual strains of Enterococcus faecalis and Pseudomonas aeruginosa (62.5 µg/mL). The sensitivity of species was not associated with its affiliation to the genus, and it could differ a lot (e.g., S. pyogenes, S. agalactiae and A. lwoffii, A. baumannii). Hence, curcumin can be considered as a promising antibacterial agent, but with a very selective activity.

Functional expression and purification of tailor-made chimeric endolysin with the broad antibacterial spectrum

Developing chimeric lysins with a wide lytic spectrum is important in fighting against Gram-negative pathogenic bacteria. In the present work, a novel chimerical lysin, LytAmfi, was constructed by fusing the bacteriophage endolysin Lyt μ1/6 with an amphipathic cationic peptide derived from T4 lysozyme. The result showed that the LytAmfi had not only lytic activity similar to parental Streptomyces aureofaciens endolysin Lyt μ1/6 but also broadened lytic activity against Gram-negative strains. Our work demonstrated that generating a novel chimeric lysin with an extended lytic spectrum was workable by fusing an active modular endolysin with an amphipathic cationic peptide that could penetrate the outer membrane of Gram-negative bacteria including Escherichia coli, Pseudomonas agglomerans, Acinetobacter lwoffii, Hafnia alvei, Citrobacter freundii and enable access of the lysin to lyse the bacteria ‘from within’ the host cell without pre-treatment of its outer membrane. Therefore, lysins with an extended spectrum of lytic activity would be of appreciable therapeutic value.

Biodegradation of n-alkanes in crude oil by three identified bacterial strains

In this study, aerobic biodegradation of crude oil was simulated using Pseudomonas aeruginosa XJ16, Bacillus cereus XJ20, and Acinetobacter lwoffii XJ19 bacteria for 90 days, for semi-quantitative calculation of concentration, demonstrating that n-alkanes (C14–C35) were biodegraded by the three strains at different ratios and rates. P. aeruginosa XJ16 showed the highest biodegradative potential for n-alkanes, with total biodegradation ratio of 98.2% in 10 days. In comparison, the total biodegradation ratio by B. cereus XJ20 increased gradually and achieved 98.8% after 90 days; whereas that by A. lwoffii XJ19 was much lower even after 90 days (29.3%). In addition, P. aeruginosa XJ16 and B. cereus XJ20 exhibited stronger biodegradation efficiencies for C18–C32n-alkanes (95.4%–99.7%) than A. lwoffii XJ19 (9.05%–73.0%). However, all three bacterial strains exhibited comparably good biodegradation efficiencies for C33–C35n-alkanes (60.2%–86.4%). Moreover, the biodegradation rate constants and biodegradation rates were of the decreasing order: P. aeruginosa XJ16 > B. cereus XJ20 > A. lwoffii XJ19. P. aeruginosa XJ16 and B. cereus XJ20 biodegrade n-alkanes with relatively low carbon numbers more easily than those with high carbon numbers. However, A. lwoffii XJ19 is more likely to biodegrade n-alkanes with relatively high carbon numbers. On day 10, surface tension (mN·m−1) declined from 70.6 to 35.9 by treatment with P. aeruginosa XJ16, to 31.3 with B. cereus XJ20, and to 34.1 with A. lwoffii XJ19. As biosurfactant-producing and hydrocarbon-degrading bacteria, these three strains have the potential to be used for bioremediation of hydrocarbon pollutants.

A novel comprehensive efficacy test for textiles intended for use in the healthcare setting

Soft surfaces, including textiles are found throughout healthcare settings. Pathogens can survive for long periods of time on textiles, and can be transferred to and from the skin. Antimicrobial fabrics are used as an engineering control to prevent infection. Efficacy testing standards have limitations, including single microorganism challenges, multiple fabric plies tested, and lengthy contact times. We developed a novel method that better models in-use conditions through testing standardized mixtures of pathogens and normal skin microorganisms, artificial soils, and a 15-min contact time. Reproducible growth of all microorganisms from frozen stocks was achieved using this method. A novel rechargeable, monitorable N-halamine cotton cellulose fabric, containing 5885 ± 98 ppm of active chlorine, was evaluated with the new method using PBS, artificial sweat, and artificial sweat plus 5% serum as soil. Pathogens tested included Acinetobacter baumannii, Candida albicans, Escherichia coli, vancomycin-resistant Enterococcus faecalis, methicillin-resistant Staphylococcus aureus, methicillin-susceptible Staphylococcus aureus, and Pseudomonas aeruginosa. Each was tested singly and in the presence of a representative normal skin flora mixture, including: Acinetobacter lwoffii, Corynebacterium striatum, Micrococcus luteus, and Staphylococcus epidermidis. When tested singly, all microorganisms were reduced by 3.00 log10 or greater, regardless of artificial soil. In mixture, 4.00 log10 or greater reductions were achieved for all microorganisms. These results suggest that the novel testing method can be used to provide more comprehensive and realistic efficacy information for antimicrobial textiles intended for use in healthcare. Furthermore, the N-halamine fabric demonstrated efficacy against multiple pathogens, singly and in mixtures, regardless of the presence of artificial soils.