Acinetobacter Haemolyticus Research Articles

The ability of Acinetobacter haemolyticus isolated from soil removes heavy elements (Cd, Pb, Zn, Ni)

The current study for the period (March 2019 - February 2020) was carried out on three different land-based ecosystems in three Iraqi governorates (Sulaymaniyah, Kirkuk, and Anbar). Soil samples were collected at nine stations close to pollution sources (Bazian cement plant, North Oil concentration area). , Haditha Desert) is located between longitude and latitude (45.062554 _ 35.577087) (44.217077 _ 34.406426) (42.269622 _ 34.8764) respectively. The relative humidity values ranged from (0.20%–39.57%) (the third station (desert) - the second station, cultivated land), while the results of bacterial numbers were recorded (75 × 310–295.66 × 510) cfu. G1-dry soil at (the third station, desert) Haditha and at the first station - Al-Wadi). 16 bacterial isolates were isolated from Acinetobacter haemolyticus. Removal was carried out under conditions of 37 °C and pH = 7, with a 24-hour incubation time. Varying concentrations of heavy elements were recorded after biological treatment with Acinetobacter haemolyticus using low concentrations (0.5, 1, 2) mg / L. The elements, cadmium (Cd), and lead (Pb) were removed. Zn, Zn, and Ni, and it was found that the total removal of lead Pb and Ni is 100% from the concentrations of low elements individually and in combination with varying values of the other elements, while there is a relative difference for the concentrations of heavy elements at high concentrations.

Demography and Impact of Initiation of Definitive Treatment in Osteoarticular Infections of Infants and Neonates

Background: Osteoarticular infections in infants, such as osteomyelitis and septic arthritis, are a growing problem with a potential for not only systemic after-effects but also irreversible joint damage and limb deformity. Therefore, early treatment is necessary to reduce permanent damage/deformity. The purpose of this study is to find out the demography and impact of early initiation of definitive institutional management in osteoarticular infections. Materials and Methods: This study was conducted after approval by the institutional review board. All neonates and infants admitted between June 2019 and May 2021 with a clinical and laboratory diagnosis of osteoarticular infection were included in this study. Data for each patient were collected using the Hosp Gestor program. Patients having a history of pain, redness, swelling in joints associated with fever, and discharging sinus from bone were studied for unknown risk factors and atypical presentations. The impact of definitive management and sequelae were noted in all patients. Results: In this study, males were affected more than females. Osteoarticular infection of septic arthritis (53%) is the most common followed by osteomyelitis (43%) affecting predominantly the hip joint. In the majority of the cases, atypical risk factors like congenital talipes equinovarus and preterm delivery were noted. The most common organism isolated was Staphylococcus aureus (35%); however, atypical organism was Acinetobacter haemolyticus (2.5%). Among treatment methods, surgical cleaning, arthrotomy, and drainage was the most common procedure. The greater the delay in institutional visit, the more severe was the complications. Worst outcomes and sequelae are seen when the delay is >3 months, namely epiphyseal growth arrest, varus deformity, and destroyed head of the femur; good outcomes are seen when a delay is for a few days. Conclusion: Early detection and institutional visit resulted in good outcomes. This study proves the truth behind the fact that delay in diagnosis and initiation of definitive treatment causes more complications and sequelae. This study also serves as a clinical guide to identify risk factors, awareness about early detection, and effective institutional treatment of osteoarticular infections in infants and neonates.

Effect of Antimicrobial Contact Lenses on Corneal Infiltrative Events: A Randomized Clinical Trial.

PurposeTo determine whether Mel4-coated antimicrobial contact lenses (MACLs) can reduce the incidence of corneal infiltrative events (CIEs) during extended wear.MethodsA prospective, randomized, double-masked, single-center, contralateral, extended contact lens wear clinical trial was conducted with 176 subjects. Each participant was randomly assigned to wear a MACL in one eye and an uncoated control contact lens in the contralateral eye or an extended-wear biweekly disposable modality for 3 months. The main outcome measures were the incidence of CIEs per 100 eye-months, identification of the microbial types colonizing the contact lenses or eyes at the time of the CIEs, and their susceptibility to Mel4.ResultsNine participants (5.1%) experienced unilateral CIEs; six participants had contact lens acute red eye, and three participants had infiltrative keratitis. The incidence rate for CIEs (0.4 events per 100 participant months; 1.7%) in the Mel4-coated lenses (test) was 69% less than that of the control lenses (1.3 events per 100 participant months; 3.4%; P = 0.29). All Gram-negative bacteria isolated from lenses and lids of participants with CIEs (Citrobacter diversus, Acinetobacter haemolyticus, and Acinetobacter lwoffii) were susceptible to Mel4 peptide; minimum inhibitory concentrations ranged from 15.6 to 62.5 µg/mL. Reduction of adhesion of these bacteria by Mel4-coated lenses ranged from 2.1 to 2.2 log10 colony-forming units/lens.ConclusionsMACLs had the capacity to reduce CIEs by at least 50% compared with uncoated control lenses during extended wear over 3 months; however, due to the relatively low rates of CIEs, the reduction was not statistically different compared with control lenses.Translational RelevanceThis study provides evidence that antimicrobial contact lenses have the potential to reduce the incidence of corneal infiltrative events during extended wear.

A crucial review on polycyclic aromatic Hydrocarbons - Environmental occurrence and strategies for microbial degradation

Over the last century, contamination of polycyclic aromatic hydrocarbons (PAHs) has risen tremendously due to the intensified industrial activities like petrochemical, pharmaceutical, insecticides and fertilizers applications. PAHs are a group of organic pollutants with adverse effects on both humans and the environment. These PAHs are widely distributed in various ecosystems including air, soil, marine water and sediments. Degradation of PAHs generally occurs through processes like photolysis, adsorption, volatilization, chemical degradation and microbial degradation. Microbial degradation of PAHs is done by the utilization of diverse microorganisms like algae, bacteria, fungi which are readily compatible with biodegrading/bio transforming PAHs into H2O, CO2 under aerobic, or CH4 under anaerobic environment. The rate of PAHs degradation using microbes is mainly governed by various cultivation conditions like temperature, pH, nutrients availability, microbial population, chemical nature of PAHs, oxygen and degree of acclimation. Several microbial species including Selenastrum capricornutum, Ralstonia basilensis, Acinetobacter haemolyticus, Pseudomonas migulae, Sphingomonas yanoikuyae and Chlorella sorokiniana are known to degrade PAHs via biosorption and enzyme-mediated degradation. Numerous bacterial mediated PAHs degradation methods are studied globally. Among them, PAHs degradation by bacterial species like Pseudomonas fluorescence, Pseudomonas aeruginosa, Rhodococcus spp., Paenibacillus spp., Mycobacterium spp., and Haemophilus spp., by various degradation modes like biosurfactant, bioaugmentation, biostimulation and biofilms mediated are also investigated. In contrarily, PAHs degradation by fungal species such as Pleurotus ostreatus, Polyporus sulphureus, Fusarium oxysporum occurs using the activity of its ligninolytic enzymes such as lignin peroxidase, laccase, and manganese peroxidase. The present review highlighted on the PAHs degradation activity by the algal, fungal, bacterial species and also focused on their mode of degradation.

Molecular Characterization and Genetic Diversity of Haplogroup E Human Lice in Guinea, West Africa.

Pediculus humanus capitis, the head louse, is an obligate blood-sucking ectoparasite that occurs in six divergent mitochondrial clades (A, D, B, F, C and E). Several studies reported the presence of different pathogenic agents in head lice specimens collected worldwide. These findings suggest that head louse could be a dangerous vector and a serious public health problem. Herein, we aimed to study the mitochondrial genetic diversity, the PHUM540560 gene polymorphisms profile of head lice collected in Guinea, as well as to screen for their associated pathogens. In 2018, a total of 155 head lice were collected from 49 individuals at the Medicals Centers of rural (Maférinyah village) and urban (Kindia city) areas, in Guinea. Specimens were subjected to a genetic analysis and pathogens screening using molecular tools. Results showed that all head lice belonged to eight haplotypes in the E haplogroup, with six newly identified for the first time. The study of the PHUM540560 gene polymorphisms of our clade E-head lice revealed that 82.5% exhibited the same polymorphism profile as the previously reported clade A-body lice. Screening for targeted pathogens revealed the presence of Acinetobacter spp., while sequencing highlighted the presence of several species, including Acinetobacter baumannii, Acinetobacter nosocomialis, Acinetobacter variabilis, Acinetobacter towneri and for the first time Acinetobacter haemolyticus. Our study is the first to report the existence of the Guinean haplogroup E, the PHUM540560 gene polymorphism profile as well as the presence of Acinetobacter species in head lice collected from Guinea.

A new bioremediation method for removal of wastewater containing oils with high oleic acid composition: Acinetobacter haemolyticus lipase immobilized on eggshell membrane with improved stabilities

As a result of the increasing demand for edible oils, which are an important part of human nutrition, in recent years, serious environmental problems may arise both during the production and after consumption of these oils.

Antibiotics Resistant Genes and Plasmid curing of Multidrug Resistant Clinical Bacterial Isolates from the Three Geographical Regions of Ondo State, Nigeria

This study shows the characteristics of multidrug resistant clinical isolates analyzed for their antibiotic resistant genes in laboratory. Genomic DNA was then extracted from each sample using Column-pure Bacteria Genomic DNA Isolation kit. Similarly, plasmid profile, plasmid curing and the antibiotic susceptibility profile of thirty two (32) cultured multidrug resistant clinical isolates were analyzed for their antibiotic resistant genes. The bacterial species tested are Acinetobacter haemolyticus, Budricia aquatic, Burkhoderia cepacia, Citrobacter gilleric, Enterobacter gergoriac,Enterobacter agglomerane, Escherichia coli, Escherichia hermamii, Klebsiella oxytoca, Klebsiella ornithinolytica, Klebsiella terrigena, Pseudomonas aeruginosa, Pseudomonas fluorescens, Staphylococcus spp., Staphylococcus aureus and coagulase –ve, Staphylococcus spp. Nutrient agar and Mueller Hinton Agar were used routinely during the study. The genomic test done on the thirty two (32) multidrug resistant strains did not show any resistant gene. But, the molecular plasmid profile conducted shows that all the isolates possess plasmid. Plasmid curing done reduces the antibiotics resistance nature of the isolates. This shows that the resistance of the isolates were plasmid mediated. The re-assessment of the antibiotic susceptibility profile of the clinical bacterial isolates tested confirmed this. It was also clarified in this study that most of the selected resistant bacterial strains isolated from hospitals were susceptible to medicinal plants such as Moringa oleifera and Andrographis peniculata tested on them. This implies that the use of appropriate medicinal plants can be optimized for pharmaceutical purpose to overcome infections caused by these aetiologic agents.

The Profile of Ciprofloxacin-Resistant Bacteria in the Rectum of Patients Undergoing Transrectal Ultrasound-Guided Prostate Biopsy, Its Relation to Post-Biopsy Infection and Alternative Prophylactic Antibiotics

Background: Fluoroquinolone has been routinely given as a prophylactic antibiotic to patients undergoing transrectal ultrasound (TRUS)-guided prostate biopsy. Currently, there is no data on the profile of fluoroquinolone-resistant bacteria, its association with post-biopsy sepsis, and alternative prophylactic antibiotics.Methods: A cross-sectional study was conducted in patients undergoing TRUS-guided prostate biopsy at Urology Clinic, Cipto Mangunkusumo National Central General Hospital between August and December 2015. Specimens were taken from rectal swabs prior to biopsy. Gramnegative bacilli and Gram-positive cocci were characterized on the Vitek®2 using GN and GP cards (BioMérieux, USA). Antimicrobial susceptibility testing was done by Kirby Bauer disc diffusion method. Post-biopsy infection was monitored within one week after biopsy by telephone call and diagnosed by clinical examination.Results: A total of 52 patients aged 52-80 years were enrolled. Sixty-six isolates grew from 52 swabs; 14 swabs among them grew 2 isolates. The commonest pathogen was Escherichia coli (78.8%), followed by Klebsiella pneumoniae (13.6%), Enterococcus faecium (3.0%), Acinetobacter haemolyticus, Morganella morganii subsp. morganii, and Enterococcus faecalis (1.5%), respectively. Ciprofloxacin-resistant bacteria were found in 33 (50.0%) isolates which were predominated by E. coli. Meanwhile, 90.4% and 96.2% of isolates were sensitive to amoxicillinclavulanate and ampicillin-sulbactam, respectively. Post-biopsy infection was established in 7 patients requiring no hospitalization.Conclusions: The proportion of ciprofloxacin-resistant bacteria in the rectum among patients undergoing prostate biopsy was 50.0%. Escherichia coli is the commonest resistant pathogen to fluoroquinolone. The recommended alternatives for prophylactic antibiotics are amoxicillinclavulanate and ampicillin-sulbactam. Routine pre-biopsy rectal swab cultures should also be encouraged.

Nitrate removal performances of a new aerobic denitrifier, Acinetobacter haemolyticus ZYL, isolated from domestic wastewater.

A new aerobic denitrifying bacterium ZYL was isolated from domestic wastewater sludge and identified as Acinetobacter haemolyticus (similarity 99%) by the 16S rDNA sequencing analysis. The strain could use nitrate, nitrite and ammonium as the sole N-source for growth with a final product of N2, demonstrating its good abilities for aerobic denitrification and heterotrophic nitrification. Single-factor experiment results showed that the effective removal of nitrate by strain ZYL occurred with carbon source sodium succinate, C/N 16-24, pH 5-9, temperature 20-40°C, DO ≥ 4.84mg/L. Ammonium was preferentially used by strain ZYL with nitrate and ammonium as the mixed nitrogen sources. According to nitrogen utilization, nitrogen balance analysis, enzyme assay and denitrifying gene amplification, nitrate was assimilated directly by the isolate for cell synthesis and also converted into N2 through aerobic denitrification. All these make strain ZYL an ideal choice for treating nitrogen-containing wastewater.

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.

Analysis of the impact of Colour of Storage Container and Storage Conditions on Bacteria flora Water

The consequence of storage and colour of buckets on the bacteriological quality of borehole water was investigated. Water samples drawn from the borehole were collected into covered tap-fitted buckets of different colours. A set of buckets were stored outdoor while duplicates were stored indoor. The physicochemical and bacteriological parameters were analyzed. There was a gradual increase in the pH of the samples during storage. Suspended solid content, bacterial count and coliform count declined with storage. There was reduction in the total bacteria count by 94.84%; 98.72%, 91.03%; 96.15%, 92.30; 96.15 and 93.60; 97.44 from an initial 78 x 10² CFU/ml for indoor and outdoor storage in the colourless, black, green and blue buckets respectively. There was also reduction in total coliform count by 95.24%; 100.00%, 90.48%; 95.24%, 90.48%; 97.62%, 92.86%; 97.62 from an initial 42 x 10² CFU/ml for indoor and outdoor storage in the colourless, black, green and blue buckets respectively. Eleven bacteria including Bacillus subtilis and Acinetobacter haemolyticus were isolated. Proteus vulgaris and Pseudomonas aeruginosa survived till the last day of storage. Decrease in bacterial counts was prominent in the colourless and blue buckets stored outdoor making them the colour of choice for use in water storage tanks.

Chromosome Architecture and Gene Content of the Emergent Pathogen Acinetobacter haemolyticus.

Acinetobacter haemolyticus is a Gammaproteobacterium that has been involved in serious diseases frequently linked to the nosocomial environment. Most of the strains causing such infections are sensitive to a wide variety of antibiotics, but recent reports indicate that this pathogen is acquiring very efficiently carbapenem-resistance determinants like the blaNDM-1 gene, all over the world. With this work we contribute with a collection set of 31 newly sequenced nosocomial A. haemolyticus isolates. Genome analysis of these sequences and others collected from RefSeq indicates that their chromosomes are organized in 12 syntenic blocks that contain most of the core genome genes. These blocks are separated by hypervariable regions that are rich in unique gene families, but also have signals of horizontal gene transfer. Genes involved in virulence or encoding different secretion systems are located inside syntenic regions and have recombination signals. The relative order of the synthetic blocks along the A. haemolyticus chromosome can change, indicating that they have been subject to several kinds of inversions. Genomes of this microorganism show large differences in gene content even if they are in the same clade. Here we also show that A. haemolyticus has an open pan-genome.

Importance of Selected Acinetobacter AAC(6′)‐Ig Active Site Residues on Escherichia coli Susceptibility to Aminoglycosides

Aminoglycosides are broad‐spectrum antibiotics commonly used to treat infections caused by Gram‐negative pathogens. However, bacteria become resistant to these antibiotics by acquiring or utilizing innate aminoglycoside acetyltransferases (AACs) that modify the drug. For instance, Acinetobacter haemolyticus has acquired the AAC(6′)‐Ig enzyme and is resistant to multiple aminoglycosides. However, our current understanding of the key residues of the active site that are critical for enzymatic activity of this enzyme is limited. Therefore, we selected two residues in the active site of the protein that formed either H‐bonds or exhibited pi‐pi stacking with tobramycin in the 3D structure of the enzyme and mutated them to bulky or charged amino acids. Next, we examined the susceptibility of Escherichia coli in the presence and absence of these over‐expressed Acinetobacter proteins toward four aminoglycosides. We found the identity of the residue substituted at these positions altered their susceptibility to these antibiotics, which provides insight into how this enzyme recognizes and modifies its diverse substrates.Support or Funding InformationResearch reported in this work was supported by the National Institute of General Medical Sciences of the National Institutes of Health under Award Number R35GM133506 (to MLK).

Small Changes of Active Site Residues of an Acinetobacter Aminoglycoside Acetyltransferase Affect Antibiotic Susceptibility

Antibiotics are drugs used to treat bacterial infections by inhibiting growth and proliferation of microorganisms. Commonly prescribed broad‐spectrum antibiotics include aminoglycosides, but many bacteria have developed resistance to these drugs by acquiring enzymes that acetylate them. We previously reported the structural and kinetic characterization of two of these enzymes from Acinetobacter. However, several outstanding questions regarding the role of specific residues in the active site of these proteins remain. In particular, we observed an active site residue that was different between these two enzymes and appeared to alter the aminoglycoside binding pocket. It has been previously shown that active site mutations within aminoglycoside acetyltransferase enzymes can adjust their ability to modify aminoglycosides and therefore their susceptibility. Since we cannot predict which point mutations will ultimately enhance their activity and therefore resistance to aminoglycosides, we performed saturation mutagenesis of this residue in the Acinetobacter haemolyticus AAC(6′)‐Ig enzyme and tested the antibiotic susceptibility of Escherichia coli to four different aminoglycosides when these mutants were overexpressed. We found the identity of the amino acid at this position was critical for altering the susceptibility of E. coli to these antibiotics. Additionally, these mutants exhibited different susceptibility patterns depending upon the identity of aminoglycoside tested. Our results show how small changes of active site residues of aminoglycoside acetyltransferase can drastically affect bacterial susceptibility to aminoglycosides, and may provide insight to which antibiotics could be effective for treating Acinetobacter infections.Support or Funding InformationResearch reported in this work was supported by the National Institute of General Medical Sciences of the National Institutes of Health under Award Number R35GM133506 (to MLK).

Molecular docking and molecular dynamics simulations of a mutant Acinetobacter haemolyticus alkaline-stable lipase against tributyrin

We previously reported on a mutant lipase KV1 (Mut-LipKV1) from Acinetobacter haemolyticus which optimal pH was raised from 8.0 to 11.0 after triple substitutions of surface aspartic acid (Asp) with lysine (Lys). Herein, this study further examined the Mut-LipKV1 by molecular docking, molecular dynamics (MD) simulations and molecular mechanics-Poisson Boltzmann surface area (MM-PBSA) calculations to explore the structural requirements that participated in the effective binding of tributyrin and its catalytic triad (Ser165, Asp259 and His289) and identify detailed changes that occurred post mutation. Mut-LipKV1 bound favorably with tributyrin (−4.1 kcal/mol) and formed a single hydrogen bond with His289, at pH 9.0. Despite the incongruent docking analysis data, results of MD simulations showed configurations of both the tributyrin-Mut-LipKV1 (RMSD 0.3 nm; RMSF 0.05 − 0.3 nm) and the tributyrin-wildtype lipase KV1 (tributyrin-LipKV1) complexes (RMSD 0.35 nm; RMSF 0.05 − 0.4 nm) being comparably stable at pH 8.0. MM-PBSA analysis indicated that van der Waals interactions made the most contribution during the molecular binding process, with the Mut-LipKV1-tributyrin complex (−44.04 kcal/mol) showing relatively lower binding energy than LipKV1-tributyrin (−43.83 kcal/mol), at pH 12.0. All tributyrin-Mut-LipKV1 complexes displayed improved binding free energies over a broader pH range from 8.0 − 12.0, as compared to LipKV1-tributyrin. Future empirical works are thus, important to validate the improved alkaline-stability of Mut-LipKV1. In a nutshell, our research offered a considerable insight for further improving the alkaline tolerance of lipases. Communicated by Ramaswamy H. Sarma

Comparative genomics analysis of Acinetobacter haemolyticus isolates from sputum samples of respiratory patients

Acinetobacter haemolyticus (A. haemolyticus) is a significant Acinetobacter pathogen, and the resistance of A. haemolyticus continues to rise due to abuse of antibiotics and the frequent gene exchange between bacteria in hospital. In this study, we performed complete genome sequencing of two A. haemolyticus strains TJR01 and TJS01 to improve our understanding of pathogenic and resistance of A. haemolyticus. Both TJR01 and TJS01 contain one chromosome and two plasmids. Compared to TJS01, more virulence factors (VFs) associated pathogenicity and resistant genes were predicted in TJR01 due to T4SS and integron associated with combination and transport. Antimicrobial susceptibility results were consistent with sequencing. We suppose TJS01 was a susceptive strain and TJR01 was an acquired multidrug resistance strain due to plasmid-mediated horizontal gene transfer. We hope these findings may be helpful for clinical treatment of A. haemolyticus infection and reduce the risk of potential outbreak infection.

Kurstakin molecules facilitate diesel oil assimilation by Acinetobacter haemolyticus strain 2SA through overexpression of alkane hydroxylase genes

ABSTRACT Biodegradation is a cost-effective process commonly used to eliminate many xenobiotic hydrocarbons such as diesel oils. However, their hydrophobic character reduces the biodegradation efficiency. In order to overcome this hurdle, kurstakins isolated from Bacillus thuringiensis strain 7SA were used as emulsifying agents. The influence of kurstakin molecules on diesel oil degradation by Acinetobacter haemolyticus strain 2SA was evaluated in the presence and absence of the aforementioned lipopeptide. The degradation rates and gene expressions of alkane hydroxylases were evaluated at days 4, 10, 14 and 21. Results showed that kurstakin molecules increased the hydrophobicity of 2SA. Moreover, diesel oil degradation activities were higher in the presence of kurstakin with 29%, 35%, 29% and 23% improvement at 4th, 10th, 14th and 21st day respectively. Statistical analysis indicated that the difference between the degradation rates in the presence and absence of kurstakin was significant with p = 0.03. The detection of three different hydroxylase genes namely alkB, almA and cyp153 in 2SA genome, might have allowed more efficient degradability of alkanes. According to the real-time PCR results, cyp153 was the most induced gene during diesel oil degradation in the presence and absence of kurstakin. Yet, the three genes demonstrated higher levels of expression in the presence of kurstakin when compared to its absence. This study showed that kurstakins enhance the diesel oil biodegradation rate by increasing the hydrophobicity of 2SA. In addition to their anti-fungal activities, kurstakins can be used as biosurfactant to increase biodegradation of diesel oil.

Molecular characterization and antimicrobial susceptibility of bacterial isolates present in tap water of public toilets.

Background The present study was carried out to investigate the tap water quality of public toilets in Amritsar, Punjab, India.Methods Water samples from the taps of the public toilets were collected in sterile containers and physicochemical and bacteriological analysis was performed using standard methods. Also, genotypic and phenotypic characterization of the bacterial isolates was performed using different biochemical tests and 16S ribosomal RNA analysis. An antibiotic susceptibility test was performed using antibiotics based on their mode of action. A biofilm assay was performed to assess the adhesion potential of the isolates.Results A total of 25 bacterial isolates were identified from the water samples, including Acinetobacter junii, Acinetobacter pittii, Acinetobacter haemolyticus, Bacillus pumilus, Bacillus megaterium, Bacillus marisflavi, Bacillus flexus, Bacillus oceanisediminis, Pseudomonas otitidis, Pseudomonas sp. RR013, Pseudomonas sp. RR021, Pseudomonas sp. RR022, Escherichia coli and Enterobacter cloacae. The results of the antimicrobial susceptibility test revealed that the antibiotics cefodroxil, aztreonam, nitrofurantoin, cefepime, ceftazidime and amoxyclav were found to be mostly ineffective against various isolates. The biofilm assay revealed the weak, moderate and strong biofilm producers among them.ConclusionsThe tap water in the public toilets was microbially contaminated and needs to be monitored carefully. The antibiotic susceptibility profile showed that of 25 bacterial isolates, 5 were multidrug resistant. Bacterial isolates exhibited strong to weak adhesion potential in the biofilm assay.

In silico mutation on a mutant lipase from Acinetobacter haemolyticus towards enhancing alkaline stability

Alkaline-stable lipases are highly valuable biocatalysts that catalyze reactions under highly basic conditions. Herein, computational predictions of lipase from Acinetobacter haemolyticus and its mutant, Mut-LipKV1 was performed to identify functionally relevant mutations that enhance pH performance under increasing basicity. Mut-LipKV1 was constructed by in silico site directed mutagenesis of several outer loop acidic residues, aspartic acid (Asp) into basic ones, lysine (Lys) at positions 51, 122 and 247, followed by simulation under extreme pH conditions (pH 8.0–pH 12.0). The energy minimized Mut-LipKV1 model exhibited good quality as shown by PROCHECK, ERRAT and Verify3D data that corresponded to 79.2, 88.82 and 89.42% in comparison to 75.2, 86.15, and 95.19% in the wild-type. Electrostatic surface potentials and charge distributions of the Mut-LipKV1 model was more stable and better adapted to conditions of elevated pHs (pH 8.0 − 10.0). Mut-LipKV1 exhibited a mixture of neutral and positive surface charge distribution compared to the predominantly negative charge in the wild-type lipase at pH 8.0. Data of molecular dynamics simulations also supported the increased alkaline-stability of Mut-LipKV1, wherein the lipase was more stable at a higher pH 9.0 (RMSD = ∼0.3 nm, RMSF = ∼0.05–0.2 nm), over the optimal pH 8.0 of the wild-type lipase (RMSD = 0.3 nm, RMSF = 0.05–0.20 nm). Thus, the adaptive strategy of replacing surface aspartic acid to lysine in lipase was successful in yielding a more alkaline-stable Mut-LipKV1 under elevated basic conditions.Communicated by Ramaswamy H. Sarma

Draft genome sequence of a clinical Acinetobacter haemolyticus isolate from South Africa.

Here we describe the draft genome sequence of a clinical Acinetobacter haemolyticus isolate (A109R1B4) from a rectal swab of a hospitalised patient in South Africa. Genomic DNA from the isolate was sequenced using an Illumina MiSeq platform. Generated reads were de novo assembled using Qiagen CLC Genomics Workbench. The assembled contigs were annotated and antimicrobial resistance genes and sequence type were identified. The genome comprised 281 contigs with a total assembly length of 3 371 389bp, a G+C content of 39.9% and an N50 value of 58 196bp, and reference coverage was 93.08 while the coverage was 88.08. A total of 3387 genes, 3292 coding sequences (CDS), 3175 coding genes and 95 RNA genes were detected. The antimicrobial resistance genes blaOXA-264 and aac(6')-Ig were detected. The genome sequence reported will serve as a reference point for molecular epidemiological studies of antibiotic-resistant A. haemolyticus in Africa.