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ABSTRACT blaNDM, the most prevalent carbapenemase among carbapenem-resistant Enterobacteriaceae, is thought to have emerged in India, as its initial detection in 2008 was linked to this country, and subsequent retrospective surveys had so far established the earliest blaNDM-positive strains to be isolated in India in 2005. Molecular dating and analyses suggest blaNDM emerged within Acinetobacter species decades prior to 2005 on a Tn125 transposon. Despite early reports of elevated rates of carbapenem-resistant Acinetobacter species in Israel starting in the 1990s, limited molecular data are available from this location. We searched for blaNDM among Acinetobacter species isolated in Israel between 2001 and 2006. One A. junii strain, Ajun-H1-3, isolated in January 2004, carried blaNDM-1 within a Tn125-like transposon on a 49-kb plasmid, pNDM-Ajun-H1-3, making Ajun-H1-3 the earliest NDM-positive isolate observed to date. The pNDM-Ajun-H1-3 plasmid matched numerous BJ01-like NDM-positive plasmids identified from 2005 onward in Acinetobacter species as well as Enterobacterales. These results indicate the need for further retrospective work on global strain archives to shed light on the conditions favoring the emergence as well as subsequent evolution and spread of blaNDM.IMPORTANCEThis study presents the earliest observation of blaNDM-1, isolated in a geographical region distant from where it is believed to have originated. In doing so, this study provides novel insights into the emergence and spread of blaNDM, the most prevalent carbapenemase among carbapenem-resistant Enterobacteriaceae, and its associated mobile genetic elements. It also sheds light on the conditions that foster the evolution of antimicrobial resistance, one of the greatest public health challenges we face.

Acinetobacter are Gram-negative coccobacilli comprising of Acinetobacter baumannii and Acinetobacter lwoffii as commonly isolated species of the genus Acinetobacter from clinical specimens. The other species of the genus Acinetobacter are rarely isolated from clinical specimens and usually considered as environmental contaminants. Acinetobacter junii has rarely been reported globally causing opportunistic infections in immunocompromised individuals. We reported a series of four clinical cases due to Acinetobacter junii infection in a tertiary care teaching institute from Uttar Pradesh, India. Among these reported cases first case was peritonitis, second and third cases were catheter associated urinary tract infection and fourth case was ventilator associated pneumonia. All these cases were reported among immunocompromised individuals and Acinetobacter junii was identified by VITEK-2 Compact automated system which was further reconfirmed by conventional biochemical tests. These isolates were found to be susceptible against most of the antimicrobials.

ABSTRACT Acinetobacter junii is an opportunistic human and animal pathogen severely understudied. Here, we conducted the largest genomic epidemiological study on this pathogen to date. Our data show that this bacterium has spread globally. Also, we found that some human and non-human isolates are not well differentiated from one another, implying transmission between clinical and non-clinical, non-human settings. Remarkably, human but also some non-human isolates have clinically important antibiotic resistance genes, and some of these genes are located in plasmids. Given these results, we put forward that A. junii should be considered an emerging One Health problem. In this regard, future molecular epidemiological studies about this species will go beyond human isolates and will consider animal-, plant-, and water-associated environments.IMPORTANCEAcinetobacter baumannii is the most well-known species from the genus Acinetobacter. However, other much less studied Acinetobacter species could be important opportunistic pathogens of animals, plants and humans. Here, we conducted the largest genomic epidemiological study of A. junii, which has been described as a source not only of human but also of animal infections. Our analyses show that this bacterium has spread globally and that, in some instances, human and non-human isolates are not well differentiated. Remarkably, some non-human isolates have important antibiotic resistance genes against important antibiotics used in human medicine. Based on our results, we propose that this pathogen must be considered an issue not only for humans but also for veterinary medicine.

ABSTRACTTigecycline is an antibiotic of last resort for infections with carbapenem-resistant Acinetobacter baumannii. Plasmids harboring variants of the tetracycline destructase gene tetX promote rising tigecycline resistance rates. We report the earliest observation of tet(X3) in a clinical strain predating tigecycline’s commercialization, suggesting selective pressures other than tigecycline contributed to its emergence.IMPORTANCEWe present the earliest observation of a tet(X3)-positive bacterial strain, predating by many years the earliest reports of this gene so far. This finding is significant as tigecycline is an antibiotic of last resort for carbapenem-resistant Acinetobacter baumannii (CRAB), which the World Health Organization ranks as one of its top three critical priority pathogens, and tet(X3) variants have become the most prevalent genes responsible for enabling CRAB to become tigecycline resistant. Moreover, the tet(X3)-positive strain we report is the first and only to be found that predates the commercialization of tigecycline, an antibiotic that was thought to have contributed to the emergence of this resistance gene. Understanding the factors contributing to the origin and spread of novel antibiotic resistance genes is crucial to addressing the major global public health issue, which is antimicrobial resistance.

Acinetobacter are Gram-negative coccobacilli comprising of Acinetobacter baumannii and Acinetobacter lwoffii as commonly isolated species of the genus Acinetobacter from clinical specimens. The other species of the genus Acinetobacter are rarely isolated from clinical specimens and usually considered as environmental contaminants. Acinetobacter junii has rarely been reported globally causing opportunistic infections in immunocompromised individuals. We reported a series of four clinical cases due to Acinetobacter junii infection in a tertiary care teaching institute from Uttar Pradesh, India. Among these reported cases first case was peritonitis, second and third cases were catheter associated urinary tract infection and fourth case was ventilator associated pneumonia. All these cases were reported among immunocompromised individuals and Acinetobacter junii was identified by VITEK-2 Compact automated system which was further reconfirmed by conventional biochemical tests. These isolates were found to be susceptible against most of the antimicrobials. [ABSTRACT FROM AUTHOR]

The increasing number of multidrug-resistant Gram-negative bacteria presents a serious threat to global health. However, colistin-resistant Acinetobacter junii has rarely been reported. We identified a colistin-resistant A. junii clinical isolate, AJ6079, in blood. The colony of AJ6079 presented a dry phenotype, and it was difficult to form a bacterial suspension, whilst transmission electron microscopy revealed that AJ6079 possessed a thick outer membrane. The phenotypic and genomic comparisons were conducted with one colistin-susceptible A. junii, which had the same antibiotic susceptibility profile except for colistin, and had the same KL25 capsule biosynthesis locus. The AJ6079 exhibited a slower growth rate, indicating that colistin-resistant A. junii possesses a higher fitness cost. The genome of AJ6079 had a G+C content of 38.7% and contained one 3,362,966 bp circular chromosome with no plasmid or mobile colistin resistance (mcr) gene. Comparative genomic analysis revealed that the AJ6079 contained several previously unreported point mutations in colistin-resistance-related genes involving amino acid substitutions in PmrB (N5K, G147C), LpxA (I107F, H131Y), and LpxD (F20I, K263R), which might be correlated with colistin resistance in A. junii. Further research is needed for verification as the genetic background was not exactly the same between the two isolates. [ABSTRACT FROM AUTHOR]

Water is an excellent source of essential nutrients which plays a significant role not only in the digestion and absorption of food but also in the elimination of waste products through urine. Most of the aquatic systems are inhabited by fungi and bacteria as their natural environments. A wide variety of bacterial species maintains, develops and exchanges genetic elements that represent a risk to human and ecological health. The presence of different types of bacteria in drinking water indicates contamination and associated health risk. Herein, a total of 11 water samples were collected in the sterile containers from different drinking stations of an educational institution of Mullana; followed by physicochemical and bacteriological analyses using standard methods. Water samples were cultured on selective agar media. Serial dilutions were performed and CFUs were calculated by the spread plate count method. Molecular identification and characterization of the bacterial isolates was performed using MALDI-TOF MS while the antibiotic susceptibility testing was performed for all the positive cultures using Kirby-Bauer disk diffusion assay and VITEK system. The results showed that Acinetobacter junii and Enterobacter cloacae, Pseudomonas aeruginosa were most prevalently detected pathogenic bacteria in the drinking water samples with high CFU ml−1 counts. The primary purpose of this study was to make people aware about the existence of bacterial load in drinking water. The present investigation indicates the dominance of Acinetobacter species in the samples of drinking water examined under the conditions employed. [ABSTRACT FROM AUTHOR]

Abstract Purpose The study aims to search for potent cellulase producer from the gut of Gryllotalpa africana as well as to characterize and determine the effect of the purified enzyme on the cellulosic waste materials. Methods The potent cellulolytic strain was identified through morphological, biochemical, physiological, and molecular characterization like 16S rRNA and fatty acid methyl ester profile. After the optimization of cellulase production, the enzyme was purified through DEAE-Sepharose column chromatographic separation. The molecular weight of the purified enzyme was determined by SDS-PAGE analysis. The purified enzyme was characterized in terms of its activity and its effect on cotton fiber, and sawdust was also studied. Result The selected potent strain GAC 16.2 was identified as Acinetobacter junii that was capable to produce enhanced cellulase (112.38 ± 0.87 U/ml) at standardized optimum fermentation conditions. The molecular weight of the purified enzyme was determined as 55 kDa. The utmost activity of the purified enzyme was detected pH 7.0, temperature 50 °C, and in the presence of metal ions like Mg2+ and Mn2+. The substantive degradation of cotton fiber and sawdust has been observed in a reasonably short period. Conclusion Purified cellulase from the selected isolate A. junii GAC16.2, a gut isolate of G. africana, has the potentiality to degrade cellulosic substances. This property can make the isolate a potent candidature for industrial application, as well as an effective biotechnological tool for environmental monitoring through cellulosic waste management.

ABSTRACT Carbapenem resistance is increasing among Gram-negative bacteria, including the genus Acinetobacter. This study aimed to characterize, for the first time, the development of carbapenem resistance in clinical isolates of Acinetobacter junii and Acinetobacter nosocomialis conferred by the acquisition of a plasmid-borne blaOXA-24/40 gene and also to characterize the dissemination of this gene between species of Acinetobacter. Carbapenem-resistant A. nosocomialis HUAV-AN66 and A. junii HUAV-AJ77 strains were isolated in the Arnau de Vilanova Hospital (Spain). The genomes were sequenced, and in silico analysis were performed to characterize the genetic environment and the OXA-24/40 transmission mechanism. Antibiotic MICs were determined, and horizontal transfer assays were conducted to evaluate interspecies transmission of OXA-24/40. Carbapenems MICs obtained were ≥64 mg/L for HUAV-AN66 and HUAV-AJ77. Genome analysis revealed the presence in both strains of a new plasmid, designated pHUAV/OXA-24/40, harboring the carbapenem-resistance gene blaOXA-24/40 and flanked by sequences XerC/XerD. pHUAV/OXA-24/40 was successfully transferred from A. nosocomialis and A. junii to a carbapenem-susceptible A. baumannii strain, thus conferring carbapenem resistance. A second plasmid (pHUAV/AMG-R) was identified in both clinical isolates for the successful horizontal transfer of pHUAV/OXA-24/40. blaOXA-24/40-carrying plasmids of the GR12 group and showing high identity with pHUAV/OXA-24/40 were identified in at least 8 Acinetobacter species. In conclusion the carbapenemase OXA-24/40 is described for the first time in A. nosocomialis and A. junii. In both isolates the blaOXA-24/40 gene was located in the GR12 pHUAV/OXA-24/40 plasmid. GR12 plasmids are implicated in the dissemination and spread of carbapenem resistance among Acinetobacter species. IMPORTANCE Acinetobacter baumannii is one of the most relevant pathogens in terms of antibiotic resistance. The main resistance mechanisms are the carbapenem-hydrolyzing class D β-lactamases (CHDLs), especially OXA-23 and OXA-24/40. In addition to A. baumannii, there are other species within the genus Acinetobacter, which in general exhibit much lower resistance rates. In this work we characterize for the first time two clinical isolates of Acinetobacter nosocomialis and Acinetobacter junii, isolated in the same hospital, carrying the carbapenemase OXA-24/40 and displaying high resistance rates to carbapenems. By means of bioinformatics analysis we have also been able to characterize the mechanism by which this carbapenemase is horizontally transferred interspecies of Acinetobacter spp. The dissemination of carbapenemase OXA-24/40 between non-baumannii Acinetobacter species is concerning since it prevents the use of most β-lactam antibiotics in the fight against these resistant isolates.

Mastitis is a widespread disease in dairy cattle occurring throughout the world. The increased use of antibiotics brings about the development of antibiotic-resistant microbes. The application of antibiotics in dairy farming led to increased antibiotic resistance and represents a major obstacle for the treatment of mastitis. Recent advancements in nanotechnology led to the development of nanocolloids to overcome disadvantages posed by conventional antimicrobial agents. Hence, a novel, environmentally friendly, cost-effective, biocompatible, and long-term antibacterial represents a promising solution for medicine and farming. Hence, polyherbal nanocolloids (PHNc) was formulated by using the extracts of Syzygium aromaticum, Cinnamomum verum, Emblica officinalis, Terminalia belerica, Terminalia chebula, and Cymbopogon citratus and physicochemically characterized. From mastitis milk samples, microorganisms were isolated including Acinetobacter junii, Klebsiella pneumoniae, Pseudomonas stutzeri, and Acinetobacter baumannii and screened for antibiotic susceptibility. All the isolated strains were tested with PHNc and compared with antibiotics. Minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and biofilm assays were performed at different concentrations, and antibacterial effects were quantified. In our results, PHNc showed potent bacteriostatic, bactericidal, and antibiofilm activity against all the strains. Our results indicated that PHNc can reduce the virulence factors responsible for infection by different bacterial strains. This study confirmed that PHNc had the potential to inhibit the growth of pathogenic Gram-negative and Gram-positive strains and could be utilized as an alternative to antibiotics to inhibit multidrug-resistant microbial pathogens in cattle. [ABSTRACT FROM AUTHOR]

We present an extremely rare case of Acinetobacter species isolated from a urine sample of45-year-old male. Acinetobacter junii is the newly emerging non-Acinetobacter baumanii rarely reported as a human pathogen. In addition, few cases had been reported in the literature with variable presentation and underlying pathology. We report a unique case of Acinetobacter junii in a patient with no underlying risk factors identified. Our case illustrates an unusual scenario where Acenitobacter junii spp isolates have been grown in urine culture with no underlying renal pathology or any long-term use of antimicrobial drugs or malignancy. [ABSTRACT FROM AUTHOR]

The increasing number of multidrug-resistant Gram-negative bacteria presents a serious threat to global health. However, colistin-resistant Acinetobacter junii has rarely been reported. We identified a colistin-resistant A. junii clinical isolate, AJ6079, in blood. The colony of AJ6079 presented a dry phenotype, and it was difficult to form a bacterial suspension, whilst transmission electron microscopy revealed that AJ6079 possessed a thick outer membrane. The phenotypic and genomic comparisons were conducted with one colistin-susceptible A. junii, which had the same antibiotic susceptibility profile except for colistin, and had the same KL25 capsule biosynthesis locus. The AJ6079 exhibited a slower growth rate, indicating that colistin-resistant A. junii possesses a higher fitness cost. The genome of AJ6079 had a G+C content of 38.7% and contained one 3,362,966 bp circular chromosome with no plasmid or mobile colistin resistance (mcr) gene. Comparative genomic analysis revealed that the AJ6079 contained several previously unreported point mutations in colistin-resistance-related genes involving amino acid substitutions in PmrB (N5K, G147C), LpxA (I107F, H131Y), and LpxD (F20I, K263R), which might be correlated with colistin resistance in A. junii. Further research is needed for verification as the genetic background was not exactly the same between the two isolates.

Lipopeptide biosurfactants (LPBs) display unique properties with widespread therapeutic applications. Recently, the wound healing activity of LPBs has received more attention. However, few investigations have focused on the healing mechanisms of these compounds, particularly those that are associated with the angiogenic pathways. Therefore, the current study aimed at investigating the effect of a natural LPB produced by Acinetobacter. junii B6 on the angiogenic potential of human umbilical vein endothelial cells (HUVECs). The proliferation, migration, and three-dimensional tube forming potential of HUVECs were examined after treatment with LPB. By using western blotting, the expression of angiogenic-related genes such as hypoxia-inducible factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF) were also measured. LPB demonstrated no significant proliferative or cytotoxic effect on HUVECs at the concentrations lower than 600 µg/mL. Moreover, LPB at a concentration of 300 µg/mL caused a significant increase in the rates of migration and tube formation of HUVECs. LPB also enhanced the protein expression levels of HIF-1α and VEGF in HUVECs in a dose-dependent manner. The present results suggest that LPB might be considered a potential wound healing agent by modifying some angiogenic factors. [ABSTRACT FROM AUTHOR]

Acinetobacter junii is one of more than 50 different species belonging to the genus Acinetobacter. This bacterium is rarely reported to cause human infections. Here we described a rare case of Acinetobacter junii, which grew in urine culture approximately one month after the patient was discharged from the hospital with antibiotics for a urinary tract infection, which caused left obstructing renal calculi requiring nephrostomy tube placement.

The disease outbreaks in aquaculture system of wetlands are the major cause of fish mortality. Among various bacterial septicaemic diseases, fish mortality caused by Acinetobacter spp. is recently reported in different fish species. Fish disease outbreak was investigated in a wetland of West Bengal, India to identify the aetiological factors involved. The moribund fish were examined and subjected to bacterial isolation. Two bacterial causative agents were identified as Acinetobacter junii and Acinetobacter pittii by biochemical characterization and 16S rRNA gene amplification. Both the isolates were oxidase‐negative, nitrate‐negative, catalase‐positive and indole‐negative. The molecular identification using 16S rRNA gene sequencing and phylogenetic tree analysis further confirmed the two Acinetobacter spp. with 97%–99% similarity. The antibiotic resistance patterns of these two bacteria revealed that both of them were resistant to β‐lactam, cefalexin, cephalothin, amoxyclav, cefuroxime, cefadroxil, clindamycin, vancomycin and penicillin. In addition, A. pittii was also resistant to other antibiotics of cephams group such as ceftazidime and cefotaxime. In the challenge experiment, both A. junii and A. pittii were found to be pathogenic with LD50 of 1.24 × 105 and 1.88 × 107 cfu/fish respectively. Histopathological examination of gill, liver and kidney revealed prominent changes supporting bacterial septicaemia. The investigation reports for the first time on concurrent infection by A. junii and multidrug‐resistant (MDR)‐A. pittii as emerging fish pathogens to cause severe mortality in Labeo catla and Hypophthalmichthys molitrix in a freshwater wetland. [ABSTRACT FROM AUTHOR]

By conducting three different methods, we report on the isolation of five novel strains of non-symbiotic bacteria from crushed infective juveniles (IJs) of four species of entomopathogenic nematodes (EPN) including Heterorhabditis bacteriophora, Steinernema carpocapsae, Steinernema feltiae, and Steinernema glaseri and five bacterial species from hemolymph of insect larvae infected with EPNs. Samples of hemolymph of infected Galleria mellonella L. larvae by EPNs and crushed surface sterilized IJs were bulk streaked onto both MacConkey and NBTA agar. To further ensure diagnoses, extracted DNA from IJs bulk was subjected to PCR by 16S-rRNA bacterial universal primers. Bacteria were identified using biochemical and phylogenetic analysis. Based on 16S-rRNA gene sequence, maximum parsimony, maximum likelihood and neighbour joining phylogenetic analyses were conducted, as well as comparisons of predicted RNA secondary structures. Four species of bacteria were identified including: Stenotrophomonas maltophilia strain IR11 from S. feltiae; S. pavanii strain IR20 from S. glaseri; Acinetobacter junii strain IR8 from S. carpocapsae; and Alcaligenes faecalis strains IR1 & IR15 from S. feltiae and H. bacteriophora respectively as non-symbiotic bacteria from IJs and five species probably originated from G. mellonella intestine including Citrobacter gillenii isolate S3, Enterobacter asburiae isolate S4, Klebsiella oxytoca isolate S5, Morganella morganii isolate S6 and Serratia marcescens isolate S6.

A new approach is described to increasing the numbers of viable cells in long-term stored populations (cultures) of the hydrocarbon-oxidizing bacterium Acinetobacter junii, which involves application of humic substances (HSs). HSs are produced due to condensation and oxidation of phenolic compounds, including alkylresorcinols, factors of intercellular microbial communication with stress-potentiating and antioxidant activity. HS addition to the stationary-phase bacterial culture was shown to result in 10- to 15-fold increase in cell viability for bacterial preparations stored for 1 to 4 months under provocative conditions (free air supply, growth medium, and temperatures of 20–25°C). Analysis of death curves for experimental and control A. junii cultures revealed two phases, with the initial stage of rapid death (0.167 log CFU/mL day), usual for autolysis of the regular stationary cells, and the stage of slower death (log 0.015 CFU/mL day), typical of persister cells. This was previously shown to be the feature determining this type of phenotypic heterogeneity in the populations of opportunistic bacteria. The concentration dependence of HSs effect on persisters formation was determined. While treatment of A. junii stationary cultures with hydrogen peroxide (0.03–0.3%) as a stress factor also resulted in enhanced persisters formation (fourfold), unlike the HS-treated variants they survived for not more than 1.5 to 2 months. Plating of the control and experimental variants (with HSs or H2O2) after long-term storage (2–4 months) revealed their phase variation spectrum to change due to replacement of the dominant colony morphology phenotype by the minor ones (40% and more), which is one of the features of the dormant cystlike bacterial forms. The ratios of the variants in the control and experiments (with HSs) were different. Comparison of the chemical composition of HS preparations indicated that the most oxidized hydrophilic HSs affected formation of persister cells, while less oxidized humates with higher antioxidant activity were responsible for the viability prolongation. Thus, the effect of HSs on bacterial populations includes induction of persister cell formation (their increased number), prolongation of the colony-forming capacity in the cells surviving under provocative storage conditions, and alteration of the phase variant spectrum of the stored populations. Formation of stress-induced persister cells developing into mature dormant forms supporting survival of the population (species) was established for saprotrophic bacteria (in the case of A. junii). In practical terms, HS-induced formation of persister cells may be recommended for development of diverse bacterial preparations. [ABSTRACT FROM AUTHOR]

Purpose: The study aims to search for potent cellulase producer from the gut of Gryllotalpa africana as well as to characterize and determine the effect of the purified enzyme on the cellulosic waste materials. Methods: The potent cellulolytic strain was identified through morphological, biochemical, physiological, and molecular characterization like 16S rRNA and fatty acid methyl ester profile. After the optimization of cellulase production, the enzyme was purified through DEAE-Sepharose column chromatographic separation. The molecular weight of the purified enzyme was determined by SDS-PAGE analysis. The purified enzyme was characterized in terms of its activity and its effect on cotton fiber, and sawdust was also studied. Result: The selected potent strain GAC 16.2 was identified as Acinetobacter junii that was capable to produce enhanced cellulase (112.38 ± 0.87 U/ml) at standardized optimum fermentation conditions. The molecular weight of the purified enzyme was determined as 55 kDa. The utmost activity of the purified enzyme was detected pH 7.0, temperature 50 °C, and in the presence of metal ions like Mg2+ and Mn2+. The substantive degradation of cotton fiber and sawdust has been observed in a reasonably short period. Conclusion: Purified cellulase from the selected isolate A. junii GAC16.2, a gut isolate of G. africana, has the potentiality to degrade cellulosic substances. This property can make the isolate a potent candidature for industrial application, as well as an effective biotechnological tool for environmental monitoring through cellulosic waste management. [ABSTRACT FROM AUTHOR]

Antibiotic resistance has led to the search for more effective antimicrobial agents among plant materials that can serve as source and template for the synthesis of new antimicrobial drugs. The current study aims to analyses the oil, extracted from the leaves of Crotalaria pallida for its physicochemical and antimicrobial properties. Leaf oil was extracted by petroleum ether (40–60 °C) and its fatty acid constituents were isolated as a mixture after saponification. Mixture of fatty acid was purified by TLC and characterized by IR, GC and GC–MS analysis by converting them into their FAME. MIC of the oil against the Gram positive and Gram negative bacteria was determined by agar diffusion method. Nineteen fatty acids were identified by gas-liquid chromatography followed by GC–MS. It was found that unsaturated fatty acids were present in greater amounts than saturated fatty acids. Most predominating unsaturated and saturated fatty acids were linolenic acid (34.06 ± 0.23%) and palmitic acid (24.47 ± 0.22%) respectively. The acid value (19.63 ± 0.22) and saponification value (109.08 ± 2.87) were also estimated to evaluate the quality of the oil. The oil showed good antimicrobial activities against Gram-positive bacteria, Bacillus subtilis as well as Gram-negative bacteria, Escherichia coli and Acinetobacter junii.

In the present study the produced biosurfactant of Acinetobacter junii B6 (recently isolated from Iranian oil excavation site) were partially purified and identified by high performance thin layer chromatography (HPTLC), Fourier transform infrared spectroscopy (FTIR), and proton nuclear magnetic resonance ( 1 H NMR). Elemental analysis of the biosurfactant by energy dispersive X-ray spectroscopy (EDS) revealed that the biosurfactant was anionic in nature. The physiochemical properties of the lipopeptide biosurfactant were evaluated by determination of its critical micelle concentration (CMC) and hydrophile-lipophile balance (HLB). The produced biosurfactant decreased the surface tension of water to 36 mN m −1 with the CMC of approximately 300 mg/l. Furthermore, the solubility properties of the biosurfactant (dissolved in phosphate-buffer saline solution, pH 7.4) were investigated by turbidity examination, dynamic light scattering (DLS) measurements, and transmission electron microscopy (TEM) inspection. It could be concluded that the biosurfactant showed the spherical-shaped vesicles at a concentration higher than its CMC and the circular dichroism (CD) spectra showed that the secondary structure of the biosurfactant vesicles is dominated by the β sheet. [ABSTRACT FROM AUTHOR]

A lead-resistant bacterial strain was isolated from coal mine dump and identified as Acinetobacter junii Pb1 on basis of 16S rRNA (ribosomal ribonucleic acid) gene sequencing. The minimum inhibitory concentration of lead for the strain was 16,000 mg l and it showed antibiotic and multi metal resistance. In aqueous culture, at an initial lead (Pb(II)) concentration of 100 and 500 mg l, lead adsorption and accumulation by the isolate was 100 and 60%, at pH 7 at 30 °C after 48 and 120 h, respectively. The two fractions of exopolysaccharide (EPS), loosely associated EPS (laEPS) and bound EPS (bEPS), and whole cells (devoid of EPS) showed high binding affinity towards Pb(II). The binding affinity of laEPS towards Pb(II) (1071 mg Pb g) was three times higher than that of bEPS (321.5 mg Pb g) and 6.5 times higher than that of whole cells (165 mg Pb g). The binding affinity of EPS and whole cells with Pb(II), reported in the current study, is considerably higher as compared to that reported in the literature, till date. SEM analysis, showed an increase in thickness of cells on exposure to Pb(II) and TEM analysis, revealed its accumulation (interior of cell) and its adsorption (with the external cell surface). The isolate was also found to be positive for indole acetic acid (IAA) and 1-aminocyclopropane-1-carboxylate (ACC) deaminase production which helps in promoting plant growth. Thus, this study provides a new understanding towards Pb(II) uptake by A. junii Pb1, highlighting its potential on the restoration of Pb(II) contaminated repositories. [ABSTRACT FROM AUTHOR]

Biosurfactant producers are crucial for incremental oil production in microbial enhanced oil recovery (MEOR) processes. The isolation of biosurfactant-producing bacteria from oil reservoirs is important because they are considered suitable for the extreme conditions of the reservoir. In this work, a novel biosurfactant-producing strain Acinetobacter junii BD was isolated from a reservoir to reduce surface tension and emulsify crude oil. The biosurfactants produced by the strain were purified and then identified via electrospray ionization-Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR-MS). The biosurfactants generated by the strain were concluded to be rhamnolipids, the dominant rhamnolipids were C26H48O9, C28H52O9 and C32H58O13. The optimal carbon source and nitrogen source for biomass and biosurfactant production were NaNO3 and soybean oil. The results showed that the content of acid components increased with the progress of crude oil biodegradation. A glass micromodel test demonstrated that the strain significantly increased oil recovery through interfacial tension reduction, wettability alteration and the mobility of microorganisms. In summary, the findings of this study indicate that the newly developed BD strain and its metabolites have great potential in MEOR.

Rhizoremediation is considered as an environmentally friendly technique to deal with the contamination of petroleum hydrocarbons. The current study was aimed at checking the potential of indigenous micro-organisms isolated from rhizosphere soil being irrigated by the wastewater of petroleum refinery to degrade benzene efficiently. For this study, soil samples were taken from the discharge point of oil refinery located in Rawalpindi, Pakistan, by brushing off the soil from roots ofCannabis sativa. The soil was processed for isolation of indigenous microbial strains. Sixteen bacterial strains isolated from the soil were screened for their potential to grow using benzene as sole carbon sourcein vitro. These were exposed initially to 250 mg L−1followed by 500 and 750 mg L−1of benzene, where only seven strains were able to survive with optical density (OD600) of ≥1.1. Three better performing strains with OD600 > 1.6 were further subjected to degrade 1,000 mg L−1benzene (sole carbon source) using M9 media. The community diversity analysis for the best performing strains was carried out using 16S ribosomal RNA.Pseudomonas aeruginosa(SAR-1) was the best degrader with 85% benzene degradation in 72 hours followed byBacillus cereus(SAR-2) andAcinetobacter junii(SAR-3) with 83 and 70% efficiency, respectively. To the best of our knowledge,A. junii(SAR-3) is being reported as a benzene degrader for the first time. [ABSTRACT FROM PUBLISHER]

Antibiotic resistance has led to the search for more effective antimicrobial agents among plant materials that can serve as source and template for the synthesis of new antimicrobial drugs. The current study aims to analyses the oil, extracted from the leaves of Crotalaria pallida for its physicochemical and antimicrobial properties. Leaf oil was extracted by petroleum ether (40–60 °C) and its fatty acid constituents were isolated as a mixture after saponification. Mixture of fatty acid was purified by TLC and characterized by IR, GC and GC–MS analysis by converting them into their FAME. MIC of the oil against the Gram positive and Gram negative bacteria was determined by agar diffusion method. Nineteen fatty acids were identified by gas-liquid chromatography followed by GC–MS. It was found that unsaturated fatty acids were present in greater amounts than saturated fatty acids. Most predominating unsaturated and saturated fatty acids were linolenic acid (34.06 ± 0.23%) and palmitic acid (24.47 ± 0.22%) respectively. The acid value (19.63 ± 0.22) and saponification value (109.08 ± 2.87) were also estimated to evaluate the quality of the oil. The oil showed good antimicrobial activities against Gram-positive bacteria, Bacillus subtilis as well as Gram-negative bacteria, Escherichia coli and Acinetobacter junii. [ABSTRACT FROM AUTHOR]

A marine, gram negative, rod shaped bacterium that degrades agar was isolated from the east coast of India and was identified to be Acinetobacter junii PS12B based on 16S rRNA gene sequencing. The effect of different culture conditions, namely pH of the medium, time and temperature of incubation and the agar concentration in the medium, on the agarase production by the strain, was evaluated. The agarase production was significantly ( p <0.05) affected by the culture conditions. The optimum conditions as determined by response surface methodology were found to be a temperature of 35 °C, pH of 7.0 and time of fermentation of 33 h and agar concentration of 0.5%. Under the optimum conditions, the isolate produced 0.17 units of agarase per ml of the medium. Ammonium nitrate and sodium nitrate were the best nitrogen source in the medium for agarase production by the isolate. Supplementing the agar containing minimal media with simple sugars like glucose and galactose was found to enhance agarase production significantly by two fold. The isolate was also able to degrade carrageenan, which indicates its role in utilization of marine polysaccharides for the production of bioactive oligosaccharides. [ABSTRACT FROM AUTHOR]

Aims Despite electrophoretic patterns of ITS PCR amplicons often suggesting only a single ITS sequence variant is present in strains of Acinetobacter junii, sequence data shows differences in ITS copies between and among them. This paper set out to explain why these ITS variants arise, and whether their presence compromises the reliability of the ITS targeted methods currently available for typing Ac. junii strains. Methods and Results ITS sequences from a number of strains of Ac. junii were either downloaded from public databases or generated here by cloning and sequencing ITS PCR amplicons. ITS copies of Ac. junii strain 97338 were all 666 bp long, with identical sequences. In Ac. junii ATCC 17908T/ BCRC 14854T), ITS copies were also all identical in their lengths but now were 706/7 bp long. Two sequence variants of these 707 bp ITS were detected. One was identical in its sequence to the nine ITS copies downloaded from the whole genome sequence of Ac. junii CIP 64·5, and those in several other Ac. junii strains. The other 707 bp ITS variant occurred elsewhere only in Ac. junii strain DSM 14968 of those examined. The six ITS copies from the genome sequence of Ac. junii NIPH 182 were all 685 bp, and with identical sequences. Ac. junii strain 178 also possessed this same 685 bp ITS variant, one of six variants detected there. At least five ITS sequence variants were seen in Ac. junii strain 97380, four in strain DSM 14968 and two in the whole genome of strain 107470. Conclusions As with those of other Acinetobacter species, such ITS variants arise not from intragenomic recombination events but from the presence of different length indels. These arise from horizontal gene transfers involving ITS fragments of other Acinetobacter species. Significance and Impact of the Study The presence of these indels compromises the reliability of the ITS targeted methods available for typing Acinetobacter junii. It also precludes the value of using ITS sequences as phylogenetic markers in members of the genus Acinetobacter, since the outcomes in both cases depends on which copy variant is chosen. [ABSTRACT FROM AUTHOR]

Introduction: Infections caused by Acinetobacter junii are rarely reported. However, some outbreaks of septicemia in neonates and pediatric oncology patients, as well as meningitis, peritonitis, and ocular infection have been described. Since it is highly infrequent to find the molecular characterization of A. junii strains in literature, in this study we described the molecular characterization of A. junii isolates recovered from blood samples of a renal transplant patient. Methodology: The case was defined as a catheter-related bacteremia caused by A. junii. The patient responded favorably after catheter removal and treatment with ciprofloxacin. Results and Conclusion: The complete molecular characterization of the isolate showed that it harbored a class 1 integron and diverse DNA mobile elements. This explains its genomic plasticity for acquiring antimicrobial resistance determinants and for adapting to a nosocomial niche. [ABSTRACT FROM AUTHOR]

Extreme environmental conditions, such as pH fluctuations, high concentrations of toxicants or grazing of protozoa, can potentially be found in wastewater treatment systems. This study was carried out to provide specific evidence on how ‘bioparticles’ can resist these conditions. The term ‘bioparticle’ is used to describe a particle comprising natural zeolitized tuff with a developed biofilm of the phosphate-accumulating bacterial species,Acinetobacter junii, on the surface. The bacteria in the biofilm were protected from the negative influence of extremely low pH, high concentrations of benzalkonium-chloride and grazing byParamecium caudatumandEuplotes affinis, even under conditions that caused complete eradication of planktonic bacteria. During an incubation of 24 h, the biofilms were maintained and bacteria detached from the bioparticles, thus bioaugmenting the wastewater. The bioparticles provided a safe environment for the survival of bacteria in harsh environmental conditions and could be used for successful bioaugmentation in wastewater treatment plants. [ABSTRACT FROM PUBLISHER]

New Delhi metallo-β-lactamase-1 (NDM-1) is a novel type of metallo-β-lactamase (MBL) responsible for bacterial resistance to β-lactam antibiotics. Acinetobacter junii was previously shown to possess a MBL phenotype; however, the genes responsible for this phenotype were not identified. In this study, we reported the identification of NDM-1 gene in a clinical isolate of A. junii from a child patient in China, which was resistant to all β-lactams except aztreonam but sensitive to aminoglycosides and quinolones. The cloned NDM-1 gene contained an open reading frame of 813 bp and had a nucleotide sequence 99.9% identical (812/813) to reported NDM-1 genes carried by Acinetobacter baumannii, Enterococcus faecium, Escherichia coli, and Klebsiella pneumoniae. Recombinant NDM-1 protein was successfully expressed in E. coli BL21, and antibiotic sensitivities of the NDM-1-producing E. coli were largely similar to the A. junii 1454 isolate. The findings of this study raise attention to the emergence and spread of NDM-1-carrying bacteria in China. [ABSTRACT FROM AUTHOR]

Abstract: The immobilization of desired bacteria onto material was usually performed in synthetic media. The aim of this study was to test the immobilization of phosphate (P)-accumulating bacteria Acinetobacter junii onto natural zeolitized tuff (NZ) in the raw or sterilized municipal wastewater containing the common bacteria Escherichia coli and Enterococcus faecalis and the performance of immobilized A. junii in the same type of wastewater. In the sterilized wastewater which contained the mixture of A. junii, E. coli and E. faecalis, the A. junii was selectively immobilized onto NZ in significantly higher numbers than E. coli and E. faecalis. The A. junii added in the form of bioparticles to the wastewater containing E. coli and E. faecalis, multiplied and removed P from wastewater. The P removal from wastewater was a function of biomass of P-accumulating bacteria and not the amount of NZ or bioparticles used. The performance of A. junii was significantly better in membrane filtered than in autoclaved wastewater. The experiments that were performed in raw non sterilized wastewater showed that A. junii can be successfully immobilized onto NZ in competition with natively present heterotrophic bacteria, retain its metabolic activity and successfully remove P from such water, which makes this technology feasible from biotechnological aspect. [Copyright &y& Elsevier]

There are many kinds of ketones with antisepsis functions in the Apocynum vernetum L. fiber (ALF), but its enzymatic retting is difficult. In order to select the appropriate ALF enzymatic retting strain, wastewater from ALF retting was analyzed to screen a strain with high pectinase activity. Of the analyzed strains, the maximum pectinase activity measured was of the #2 strain: 103.2 IU/ml at a zymogenic time of 12 hrs at 37°C. The retting experiments verified that this strain was well suited for ALF; the residual gum rate of ALF was 15.26% and its fiber physicochemical properties were similar to those fibers which were chemically retted. The strain was determined to be a new retting strain, Acinetobacter junii, according to a 16S rDNA sequence analysis in combination with morphology, and biophysical and biochemical tests using fermentation, catalase, methyl red and gelatin liquefaction. As a new pectinase-producing strain, Acinetobacter junii could be utilized in industrial enzymatic retting productions after further process optimization and can replace the conventional chemical retting process due to its improved fiber quality and reduced environmental pollution. [ABSTRACT FROM AUTHOR]

Abstract: The genus Acinetobacter is an important causative pathogen of nosocomial infections in the healthcare setting. The objectives of this study were to determine the species of causative pathogens and the sources of Acinetobacter blood stream infections that occurred in 2 immunocompetent pregnant women admitted to an obstetrics ward within a 2-month period. Phenotypic identification of the two isolates from blood stream infections was inconsistent among the ID test, the MicroScan WalkAway and the Vitek2 systems. In addition to the growth profile and detailed biochemical analysis, genotypic identification and phylogenetic tree analysis based on the almost complete 16S rRNA sequence and the partial rpoB gene sequence confirmed the identification of these isolates as A. ursingii. Environmental investigation of the obstetrics ward revealed A. ursingii and different strains of Acinetobacter junii in specimens obtained from the ward shower bath, although the source and route of transmission for the A. ursingii infections were not clarified. Our findings show that A. ursingii can inhabit the hospital environment. [Copyright &y& Elsevier]

Abstract: Hemicellulose, accounting for up to 30% of lignocellulose, could play an important role in producing cellulosic bioenergy. Xylanase is the key enzyme capable of hydrolyzing hemicellulose to form fermentable five-carbon sugars for biofuel production. A cellulolytic bacterial strain isolated from soil in southern Taiwan is able to produce xylanase and cellulase extracellularly with a high efficiency. The xylanase produced by the isolated strain (identified as Acinetobacter junii F6-02) exhibits the highest activity at 60°C and pH 7.0. However, the best condition for producing xylanase by the F6-02 strain was 35°C and pH 7.0 using BHM medium supplemented with CMC (5g/L), xylan (5g/L), and peptone (1g/L). Fermentative production of xylanase was greatly influenced by oxygen supply, reaching the highest level at an aeration rate of 0.3vvm. The highest cumulative xylanase production and xylanase production rate was 317U/ml and 8.06U/ml/h, respectively. The lyophilized cellulolytic enzymes produced from A. junii F6-02 display better enzyme activity than the original crude enzyme extract and are able to perform long-term hydrolysis stably at a temperature of 50°C. [ABSTRACT FROM AUTHOR]

Abstract: Sepiolite in its original (OS) and purified form (PS) was tested as a carrier of the phosphate-accumulating bacteria Acinetobacter junii. The numbers of A. junii immobilized onto sepiolite were 5.57 and 8.12×109 CFUg−1 for OS and PS, respectively. The immobilized bacteria were metabolically active and removed phosphate from synthetic wastewater. Better phosphate removal in reactors with immobilized bacteria when compared to reactors with planktonic bacteria was mainly due to the increased bacterial biomass and at a lower extent due to the increased bacterial phosphate-uptake rates. The bioaugmentation of an activated sludge with A. junii immobilized on OS significantly improved the phosphate removal from synthetic wastewater when compared to a conventional activated sludge. [ABSTRACT FROM AUTHOR]

Abstract: Three different forms of perlite (non-expanded, semi-expanded and expanded) were tested as carriers of phosphate-accumulating bacterium Acinetobacter junii. The highest rate of immobilization of A. junii (12.65×109 CFUg−1) was obtained for expanded perlite, followed by semi-expanded (5.57×109 CFUg−1) and non-expanded (1.68×109 CFUg−1) perlite. The number of immobilized A. junii on expanded perlite was the highest among all carriers of Acinetobacter species reported in the literature so far. The immobilization of A. junii on perlite was dependent on the particle size, but not on the zeta potential of particles. The SSA of the perlite samples influenced immobilization of A. junii but was not recognized as the crucial factor. Immobilized bacteria were metabolically active and successfully removed phosphate from the wastewater when incubated in pure culture or in bioaugmented activated sludge. In the system with activated sludge the best carrier of A. junii was the semi-expanded perlite which was well incorporated in the sludge. The expanded perlite was floating on the surface of the wastewater while raw perlite sunk to the bottom of the reactor, diminishing the exposure and consequently phosphate removal of immobilized bacteria in the wastewater. [ABSTRACT FROM AUTHOR]

Abstract: Xylan and rice straw were used to produce H2 via a two-stage approach combining feedstock pretreatment/hydrolysis and dark H2 fermentation. Acinetobacter junii F6-02 was used to produce cellulolytic enzymes (mainly xylanase) to hydrolyze xylan and pretreated rice straw. The hydrolysates were converted to H2 by Clostridium butyricum CGS5 via dark fermentation. Investigation of kinetics of xylanase on xylan and NaOH-pretreated rice straw shows ν max values of 8.6 and 3.6g/L/h, and Km values of 10.6 and 26.9g/L, respectively. A maximum hydrogen production rate of 62.5 and 26.8ml/h/L was obtained from hydrolysate of xylan and pretreated rice straw, respectively, while the hydrogen yield was 0.70 and 0.76mol H2/mol xylose, respectively. Simultaneous saccharification and BioH2 fermentation from xylan was also conducted but giving a lower hydrogen production rate (35.3ml/h/L) than that of the two-stage process. [Copyright &y& Elsevier]

A multi-channel thermal activity microcalorimeter was used to determine the pyrene-induced toxic effect on two polycyclic aromatic hydrocarbon (PAH)-degrading bacteria Acinetobacter junii (A. junii) and Bacillus subtilis (B. subtilis). Power-time curves were analyzed and calorimetric parameters including growth rate constant (k), half inhibitory concentration (IC50) and total thermal effect (QT) were obtained. A. junii and B. subtilis were completely inhibited when the concentration of pyrene reached 400 and 160 μ g mL-1, respectively. The relationships between the calorimetric parameters and concentration of pyrene were studied. The growth rate of A. junii decreased with the increase in pyrene concentration at 50-200 μ g mL-1. The growth of biomass for A. junii at various concentrations of pyrene was determined. The count of A. junii after 8 day's incubation reached maximum irrespective of the initial pyrene concentrations ranging from 50 to 200 μ g mL-1 and the smallest stimulative action of pyrene was at 200 μ g mL-1. The variations of biomass during the growth of A. junii were consistent with the microcalorimetric data, indicating that microcalorimetry can be an effective technique to investigate the effect of pyrene on microorganisms. [ABSTRACT FROM AUTHOR]

The survival of two heterotrophic bacteria in conditions of various concentrations of NaCl was tested. Both bacteria can commonly enter marine environments through sewage or wastewater treatment plant effluents; the Escherichia coli is a common enteric bacterium and Acinetobacter junii is a phosphate-accumulating bacterium inhabiting activated sludge. When cultivated in nutrient rich media (COD 8700 mg O2 L-1), both bacteria were multiplying during 72 h at concentrations of NaCl up to 5% for E. coli and 3.5% for A. junii. Total die-off of E. coli was detected at 72 h by NaCl concentration of 20%. Total die-off of A. junii was detected at 72 h by NaCl concentration of 10%. When the same bacteria were cultured in nutrient depleted media (COD 90 mg O2 L-1), the multiplication of E. coli stopped at 3.5% of NaCl and higher, but the cells were able to survive for longer period of time at extreme NaCl concentrations of 20 and 30%. The negative influence of NaCl to A. junii was pronounced in conditions of organic matter shortage and rapid die-off was observed at 3.5% of NaCl and higher. Both bacteria seemed to be osmotolerant when cultured in nutrient-rich media, but not in nutrient-depleted media. [ABSTRACT FROM AUTHOR]

Abstract: The ability of non-flocculating Acinetobacter spp. isolates (A. johnsonii S35 and A. junii S33) to coaggregate with other sludge-constituting bacteria obtained from a sewage sludge sample was assessed by a spectrophotometric assay. A. johnsonii S35 showed significant coaggregation (aggregation index (AI)=70 to 99%) with 7 strains, Bacillus cereus, Blastomonas natatoria, Mycobacterium sp., Thermomonas brevis, and Enterobacteriaceae family, identified by sequencing of 16S rRNA genes. A. junii S33 coaggregated with 4 strains, which were also coaggregating partners of A. johnsonii S35, as indicated by AI values of 59–93%. The microbial adhesion to hydrocarbon (MATH) assay showed that both A. johnsonii S35 and A. junii S33 possess a hydrophobic character as indicated by their relative cell surface hydrophobicity (RCSH), 88 and 61%, respectively. A good correlation was observed between the degree of coaggregation of the Acinetobacter spp. isolates and the RCSH of their partner strains. The cells of an A. johnsonii S35 spontaneous mutant and A. johnsonii IAM1517, which had a hydrophilic cell surface, did not coaggregate with the other examined isolates. These results demonstrated that hydrophobic interaction plays an important role in the intergeneric coaggregation of Acinetobacter spp. isolates with other sludge-constituting bacteria. [Copyright &y& Elsevier]

Acinetobacter junii strain BB1A, a novel metal-tolerant bacterium, produced biofilm in the presence of added ions such as Ni2+, AsO2−, Cd2+ and Hg2+ on surfaces such as glass and polystyrene. Generation of a metal-sensitive and adhesion-deficient mutant by transposition of Tn 5-mob in the A. junii genome has putatively confirmed the association of metal tolerance with the production of biofilm. The requirement of a critical cell density for biofilm formation and presence of acyl-homoserine lactone-like autoinducer molecules in the cell-free supernatant indicated the phenomenon of quorum sensing. Addition of a natural quorum-sensing inhibitor (garlic extract) or synthetic quorum-sensing inhibitor (4-nitro-pyridine oxide) significantly inhibited cell growth and biofilm formation in the presence of metal/metalloid ions. [ABSTRACT FROM AUTHOR]