We report here the genome sequence of a multidrug-resistant Klebsiella pneumoniae strain, which caused an outbreak in a neonatal ward in 2011. The genome consists of a single chromosome (5,278 kb) and three plasmids (362 kb, 5 kb, and 4 kb). Copyright © 2015 Becker et al.
Among the Enterobacteriacea Klebsiella pneumoniae is for the most part obtained from clinical samples and most probable cause of a typical form of primary pneumonia. It can also responsible for a variety of extrapulmonary infections, counting enteritis and meningitis in infants, urinary tract infections in children and adults and septicaemia in all age groups. Like wise these pathogens are significant cause of hospital acquired infections right through the world. The remarkable increase in the prevalence of antibiotic resistance in bacteria noticed in recent years represents a considerable challenge to public health microbiology worldwide. Klebsiellae have a tendency to possess antibiotic resistant plasmids; as a result, infections with multiple antibiotic-resistant strains can be likely. Only some degree of studies had been accounted in this regard from Nepal. The study was performed from January 1999 to March 2001. To come upon the existing dated antibiotic resistance pattern of Klebsiella pneumoniae. The study was carried out at TUTH laboratory with the objectives to ascertain the prevalence of Klebsiella pneumoniae in conjunction with to calculate the significance antibiotic resistance correlation between various antibiotics. By which the later 15 years analysis of antibiotic resistance was evaluated with comparison to this study.In this scrutiny the result was established that the numbers of total isolates including both klebsiella pneumoniae and other Kebsiella species were 62 from urine samples, 78 from pus samples and 96 from sputum samples and 34 from other miscellaneous samples. In this study positive culture for Klebsiella pneumoniae was 32.83% for sputum samples, 23.62.% for urine samples and 24.57% for pus samples. Majority of the strains isolated were sensitive to ß- lactamases, Floroquinolones, Aminoglycosides, Tetracycline and Cotrimoxazole, combined antibiotics. The current review study from 1999 to 2014 discloses the frequency of infections due to klebsiella pneumoniae strains in the hospitalized patients and their tendency towards antibiotic resistance was on the increase. Large quantity of antibiotics exploited for human therapy has resulted in the selection of pathogenic bacteria resistant to multiple antimicrobial drugs. This has become a vital clinical and infection control challenge, particularly in resource-limited settings with far above the ground a raising rate of antimicrobial resistance.
Streptomyces leeuwenhoekii, isolated from the hyperarid Atacama Desert, produces the new ansamycin-like compounds chaxamycins A to D, which possess potent antibacterial activity and moderate antiproliferative activity. We report the development of genetic tools to manipulate S. leeuwenhoekii and the identification and partial characterization of the 80.2-kb chaxamycin biosynthesis gene cluster, which was achieved by both mutational analysis in the natural producer and heterologous expression in Streptomyces coelicolor A3(2) strain M1152. Restoration of chaxamycin production in a nonproducing ?cxmK mutant (cxmK encodes 3-amino-5-hydroxybenzoic acid [AHBA] synthase) was achieved by supplementing the growth medium with AHBA, suggesting that mutasynthesis may be a viable approach for the generation of novel chaxamycin derivatives. Copyright © 2015, American Society for Microbiology. All Rights Reserved.
The first complete genome sequences of Staphylococcus aureus subsp. aureus Rosenbach 1884 strain DSM 20231(T), the type strain of the bacterium causing staphylococcal disease, were determined using PacBio RS II. The sequences represent the chromosome (2,755,072 bp long; G+C content, 32.86%) and a plasmid (27,490 bp long; G+C content, 30.69%). Copyright © 2015 Shiroma et al.
Multidrug resistance, strong side effects, and compliance problems in TB chemotherapy mandate new ways to kill Mycobacterium tuberculosis (Mtb). Here we show that deletion of the gene encoding homoserine transacetylase (metA) inactivates methionine and S-adenosylmethionine (SAM) biosynthesis in Mtb and renders this pathogen exquisitely sensitive to killing in immunocompetent or immunocompromised mice, leading to rapid clearance from host tissues. Mtb ?metA is unable to proliferate in primary human macrophages, and in vitro starvation leads to extraordinarily rapid killing with no appearance of suppressor mutants. Cell death of Mtb ?metA is faster than that of other auxotrophic mutants (i.e., tryptophan, pantothenate, leucine, biotin), suggesting a particularly potent mechanism of killing. Time-course metabolomics showed complete depletion of intracellular methionine and SAM. SAM depletion was consistent with a significant decrease in methylation at the DNA level (measured by single-molecule real-time sequencing) and with the induction of several essential methyltransferases involved in biotin and menaquinone biosynthesis, both of which are vital biological processes and validated targets of antimycobacterial drugs. Mtb ?metA could be partially rescued by biotin supplementation, confirming a multitarget cell death mechanism. The work presented here uncovers a previously unidentified vulnerability of Mtb-the incapacity to scavenge intermediates of SAM and methionine biosynthesis from the host. This vulnerability unveils an entirely new drug target space with the promise of rapid killing of the tubercle bacillus by a new mechanism of action.
Infections with Acinetobacter baumannii, one of the most troublesome and least studied multidrug-resistant superbugs, are increasing at alarming rates. A. baumannii encodes a type VI secretion system (T6SS), an antibacterial apparatus of Gram-negative bacteria used to kill competitors. Expression of the T6SS varies among different strains of A. baumannii, for which the regulatory mechanisms are unknown. Here, we show that several multidrug-resistant strains of A. baumannii harbor a large, self-transmissible resistance plasmid that carries the negative regulators for T6SS. T6SS activity is silenced in plasmid-containing, antibiotic-resistant cells, while part of the population undergoes frequent plasmid loss and activation of the T6SS. This activation results in T6SS-mediated killing of competing bacteria but renders A. baumannii susceptible to antibiotics. Our data show that a plasmid that has evolved to harbor antibiotic resistance genes plays a role in the differentiation of cells specialized in the elimination of competing bacteria.
Rhipicephalus microplus, the cattle fever tick, is a global economic problem to the cattle industry due to direct infestation of cattle and pathogens transmitted during feeding. Cattle fever tick outbreaks continue to occur along the Mexico-US border even though the tick has been eradicated from the USA. The organophosphate (OP) coumaphos targets acetylcholinesterase (AChE) and is the approved acaricide for eradicating cattle fever tick outbreaks. There is evidence for coumaphos resistance developing in cattle ticks in Mexico, and OP-resistant R. microplus ticks were discovered in outbreak populations of Texas in 2005. The molecular basis of coumaphos resistance is not known, and our study was established to gather further information on whether AChE1 is involved in the resistance mechanism. We also sought information on allele diversity in tick populations with different levels of coumaphos resistance. The overarching project goal was to define OP resistance-associated gene mutations such that a DNA-based diagnostic assay could be developed to assist the management of resistance. Three different AChE transcripts have been reported in R. microplus, and supporting genomic and transcriptomic data are available at CattleTickBase. Here, we report the complete R. microplus AChE1 gene ascertained by sequencing a bacterial artificial chromosome clone containing the entire coding region and the flanking 5′ and 3′ regions. We also report AChE1 sequences of larval ticks from R. microplus strains having different sensitivities to OP. To accomplish this, we sequenced a 669-bp region of the AChE1 gene corresponding to a 223 amino acid region of exon 2 to assess alleles in seven strains of R. microplus with varying OP resistance phenotypes. We identified 72 AChE1 sequence variants, 2 of which are strongly associated with OP-resistant phenotypes. Esterase-like sequences from the R. microplus transcriptome RmiTr Version 1.0 were compared to the available sequence databases to identify other transcripts with similarity to AChE1.
Carbapenemases are a major concern for the treatment of infectious diseases caused by Gram-negative bacteria. Although plasmids are responsible for the spread of resistance genes among these pathogens, there is limited information on the nature of the mobile genetic elements carrying carbapenemases in Pseudomonas aeruginosa.We combined data from two different next-generation sequencing platforms, Illumina HiSeq2000 and PacBio RSII, to obtain the complete nucleotide sequences of two blaVIM-1-carrying plasmids (pAMBL1 and pAMBL2) isolated from P. aeruginosa clinical isolates.Plasmid pAMBL1 has 26?440 bp and carries a RepA_C family replication protein. pAMBL1 is similar to plasmids pNOR-2000 and pKLC102 from P. aeruginosa and pAX22 from Achromobacter xylosoxidans, which also carry VIM-type carbapenemases. pAMBL2 is a 24?133 bp plasmid with a replication protein that belongs to the Rep_3 family. It shows a high degree of homology with a fragment of the blaVIM-1-bearing plasmid pPC9 from Pseudomonas putida. Plasmid pAMBL2 carries three copies of the blaVIM-1 cassette in an In70 class 1 integron conferring, unlike pAMBL1, high-level resistance to carbapenems.We present two new plasmids coding for VIM-1 carbapenemase from P. aeruginosa and report that the presence of three copies of blaVIM-1 in pAMBL2 produces high-level resistance to carbapenems.© The Author 2015. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.
Serotype IV group B Streptococcus (GBS) is emerging in Canada and the United States with rates as high as 5% of the total burden of adult invasive GBS disease. To understand this emergence, we studied the population structure and assessed the antimicrobial susceptibility of serotype IV isolates causing adult invasive infection in Manitoba and Saskatchewan, Canada, between 2010 and 2014. Whole-genome sequencing was used to determine multilocus sequence typing information and identify genes encoding antimicrobial resistance in 85 invasive serotype IV GBS strains. Antimicrobial susceptibility testing was performed by standard methods. Strain divergence was assessed using genome-wide single-nucleotide polymorphism analysis. Serotype IV strains were responsible for 16.9% of adult invasive GBS infections in Manitoba and Saskatchewan during the period. The majority of serotype IV isolates (89%) were clonally related, tetracycline-, erythromycin-, and clindamycin-resistant sequence type 459 (ST459) strains that possessed genes tetM and ermTR. Genome comparisons between ST459 and serotype V ST1 GBS identified several areas of recombination in an overall similar genomic background. Serotype IV ST459 GBS strains are expanding and causing a substantial percentage of adult invasive GBS disease. This emergence may be linked to the acquisition of resistance to tetracycline, macrolides, and lincosamides. Copyright © 2015, American Society for Microbiology. All Rights Reserved.
The first complete genome sequence of the type strain Pseudomonas aeruginosa (Schroeter 1872) Migula 1900 (DSM 50071(T)) was determined in a single contig by PacBio RS II. The genome (6,317,050 bp, G+C content of 66.52%) contained 10 sets of >1,000-bp identical sequence pairs and 183 tandem repeats. Copyright © 2015 Nakano et al.
Acinetobacter baumannii is an emerging Gram-negative pathogen responsible for health care-associated infections. In this study, we determined the genome of a motility-positive clinical strain, B8342, isolated from a hospital in southern India. The B8342 genome, which is 3.94 Mbp, was generated by de novo assembly of PacBio long-read sequencing data. Copyright © 2015 Vijaykumar et al.
Bacillus strains have been widely used as the companion strain of Ketogulonigenium vulgare in the process of vitamin C fermentation. Different Bacillus strains generate different effects on the growth of K. vulgare and ultimately influence the productivity. First, we identified that Bacillus endophyticus Hbe603 was an appropriate strain to cooperate with K. vulgare and the product conversion rate exceeded 90% in industrial vitamin C fermentation. Here, we report the genome sequencing of the B. endophyticus Hbe603 industrial companion strain and speculate its possible advantage in the consortium. The circular chromosome of B. endophyticus Hbe603 has a size of 4.87 Mb with GC content of 36.64% and has the highest similarity with that of Bacillus megaterium among all the bacteria with complete genomes. By comparing the distribution of COGs with that of Bacillus thuringiensis, Bacillus cereus and B. megaterium, B. endophyticus has less genes related to cell envelope biogenesis and signal transduction mechanisms, and more genes related to carbohydrate transport and metabolism, energy production and conversion, as well as lipid transport and metabolism. Genome-based functional studies revealed the specific capability of B. endophyticus in sporulation, transcription regulation, environmental resistance, membrane transportation, extracellular proteins and nutrients synthesis, which would be beneficial for K. vulgare. In particular, B. endophyticus lacks the Rap-Phr signal cascade system and, in part, spore coat related proteins. In addition, it has specific pathways for vitamin B12 synthesis and sorbitol metabolism. The genome analysis of the industrial B. endophyticus will help us understand its cooperative mechanism in the K. vulgare-Bacillus strain consortium to improve the fermentation of vitamin C.
Neisseria gonorrhoeae, the etiological agent that causes the sexually transmitted infection gonorrhea, is a significant public health concern due to the emergence of antimicrobial resistance. We report the complete genome sequences of three reference isolates with varied antimicrobial susceptibility that will aid in elucidating the genetic mechanisms that confer resistance. Copyright © 2015 Abrams et al.
Acinetobacter baumannii is an emerging nosocomial pathogen causing infections worldwide. In this study, we determined the genome sequences of two multidrug-resistant A. baumannii clinical strains isolated from a hospital in southern India. Genome analyses indicate that both the strains harbor numerous horizontally transferred genetic elements and antibiotic resistance cassettes. Copyright © 2015 Balaji et al.
Staphylococcus schleiferi, a Gram-positive and coagulase-variable organism, is an opportunistic human pathogen and a major cause of skin and soft tissue infections in dogs. Here, we report the first S. schleiferi genome sequence and methylome from four canine clinical isolates. Copyright © 2015 Misic et al.
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