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Aljahani A, Alarjani K, Hassan Z, Elkhadragy M, Ismail E, Al-Masoud A, Yehia H. Molecular detection of methicillin heat-resistant Staphylococcus aureus strains in pasteurized camel milk in Saudi Arabia. Biosci Rep 2020; 40:BSR20193470. [PMID: 32202302 PMCID: PMC7167254 DOI: 10.1042/bsr20193470] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Revised: 03/12/2020] [Accepted: 03/19/2020] [Indexed: 11/17/2022] Open
Abstract
Antibiotic- and heat-resistant bacteria in camel milk is a potential public health problem. Staphylococcus aureus (S. aureus) is an opportunistic pathogen in humans, dairy cattle and camels. We characterized the phenotype and genotype of methicillin-resistant staphylococcal strains recovered from pasteurized and raw camel milk (as control) distributed in the retail markets of Saudi Arabia. Of the 100 samples assessed between March and May 2016, 20 S. aureus isolates were recovered from pasteurized milk, 10 of which were resistant to cefoxitin, and as such, were methicillin-resistant. However, raw camel milk did not contain methicillin-resistant S. aureus (MRSA). Antimicrobial susceptibility tests showed that the resistance ratio for other antibiotics was 60%. We performed a polymerase chain reaction (PCR) assay using primers for the methicillin-resistant gene mecA and nucleotide sequencing to detect and verify the methicillin-resistant strains. Basic local alignment search tool (BLAST) analysis of the gene sequences showed a 96-100% similarity between the resistant isolates and the S. aureus CS100 strain's mecA gene. Ten of the methicillin-resistant isolates were heat-resistant and were stable at temperatures up to 85°C for 60 s, and three of these were resistant at 90°C for 60 or 90 s. The mean decimal reduction time (D85-value) was 111 s for the ten isolates. Sodium dodecyl sulfate (SDS)/polyacrylamide gel electrophoresis (PAGE) showed that there was no difference in the total protein profiles for the ten methicillin heat-resistant S. aureus (MHRSA) isolates and for S. aureus ATCC 29737. In conclusion, a relatively high percentage of the tested pasteurized camel milk samples contained S. aureus (20%) and MHRSA (10%).
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Affiliation(s)
- Amani H. Aljahani
- Department of Physical Sport Science, Nutrition and Food Science, Princess Nourah Bint Abdulrahman University, Saudi Arabia
| | - Khaloud M. Alarjani
- Department of Botany and Microbiology, College of Science, King Saud University, Saudi Arabia
| | - Zeinab K. Hassan
- Cancer Biology Department, Virology and Immunolgy Unit, National Cancer Institute, Cairo University, Egypt
| | - Manal F. Elkhadragy
- Biology Department, Faculty of Science, Princess Nourah bint Abdulrahman University, Riyadh 11671, Saudi Arabia
- Zoology Department, Faculty of Science, Helwan University, Cairo 11790, Egypt
| | - Elsayed A. Ismail
- Department of Dairy Science, Faculty of Agriculture, Benha University, Benha 13518, Egypt
| | - Abdulrahman H. Al-Masoud
- Food Science and Nutrition Department, College of Food and Agricultural Sciences, King Saud University, Riyadh, Saudi Arabia
| | - Hany M. Yehia
- Food Science and Nutrition Department, College of Food and Agricultural Sciences, King Saud University, Riyadh, Saudi Arabia
- Food Science and Nutrition Department, Faculty of Home Economics, Helwan University, Cairo, Egypt
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Cleverley RM, Rutter ZJ, Rismondo J, Corona F, Tsui HCT, Alatawi FA, Daniel RA, Halbedel S, Massidda O, Winkler ME, Lewis RJ. The cell cycle regulator GpsB functions as cytosolic adaptor for multiple cell wall enzymes. Nat Commun 2019; 10:261. [PMID: 30651563 PMCID: PMC6335420 DOI: 10.1038/s41467-018-08056-2] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Accepted: 12/07/2018] [Indexed: 01/01/2023] Open
Abstract
Bacterial growth and cell division requires precise spatiotemporal regulation of the synthesis and remodelling of the peptidoglycan layer that surrounds the cytoplasmic membrane. GpsB is a cytosolic protein that affects cell wall synthesis by binding cytoplasmic mini-domains of peptidoglycan synthases to ensure their correct subcellular localisation. Here, we describe critical structural features for the interaction of GpsB with peptidoglycan synthases from three bacterial species (Bacillus subtilis, Listeria monocytogenes and Streptococcus pneumoniae) and suggest their importance for cell wall growth and viability in L. monocytogenes and S. pneumoniae. We use these structural motifs to identify novel partners of GpsB in B. subtilis and extend the members of the GpsB interactome in all three bacterial species. Our results support that GpsB functions as an adaptor protein that mediates the interaction between membrane proteins, scaffolding proteins, signalling proteins and enzymes to generate larger protein complexes at specific sites in a bacterial cell cycle-dependent manner.
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Affiliation(s)
- Robert M Cleverley
- Institute for Cell and Molecular Biosciences, University of Newcastle, Newcastle upon Tyne, NE2 4HH, UK
| | - Zoe J Rutter
- Institute for Cell and Molecular Biosciences, University of Newcastle, Newcastle upon Tyne, NE2 4HH, UK
| | - Jeanine Rismondo
- FG11 Division of Enteropathogenic Bacteria and Legionella, Robert Koch Institute, Burgstrasse 37, 38855, Wernigerode, Germany
- Section of Microbiology and MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, SW7 2DD, UK
| | - Federico Corona
- Dipartimento di Scienze Chirurgiche, Università di Cagliari, Cagliari, 09100, Italy
- Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, University of Newcastle, Newcastle upon Tyne, NE2 4AX, UK
| | | | - Fuad A Alatawi
- Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, University of Newcastle, Newcastle upon Tyne, NE2 4AX, UK
| | - Richard A Daniel
- Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, University of Newcastle, Newcastle upon Tyne, NE2 4AX, UK
| | - Sven Halbedel
- FG11 Division of Enteropathogenic Bacteria and Legionella, Robert Koch Institute, Burgstrasse 37, 38855, Wernigerode, Germany
| | - Orietta Massidda
- Dipartimento di Scienze Chirurgiche, Università di Cagliari, Cagliari, 09100, Italy
- Department CIBIO, University of Trento, via Sommarive 9, 38123, Povo, Italy
| | - Malcolm E Winkler
- Department of Biology, Indiana University Bloomington, Bloomington, IN, 47405, USA
| | - Richard J Lewis
- Institute for Cell and Molecular Biosciences, University of Newcastle, Newcastle upon Tyne, NE2 4HH, UK.
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Siddiqui T, Muhammad IN, Khan MN, Fatima S, Alam N, Masood R, Saeed R, Naqvi GR, Naqvi T. Prevalence of mecA: Genotyping screening of community acquired-MRSA isolates in Karachi, Pakistan. Pak J Pharm Sci 2018; 31:2091-2094. [PMID: 30393217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Among resistant nosocomial and community pathogens, MRSA has become the most serious pathogen, causing life threatening infections worldwide. In S.aureus, quick and exact recognition of methicillin (cefoxitin) resistance has become essential. The benchmark for MRSA identification among S.aureus is the detection of the mecA gene that causes the expression of protein (PBP2a) culpable for classic β-lactam resistance. However, the utter reliance on amplification of mecA gene as a hallmark in confirmation of methicillin (cefoxitin) resistant S. aureus is the matter of distrust by some investigators. The current investigation designed to analyse the prevalence of mecA gene among phenotypically positive MRSA isolates using molecular method and to correlate its prevalence to conventional techniques. Furthermore, antimicrobial sensitivity of mecA positive staphylococci was determined by Kirby Baeuer method. For this purpose, 201 clinical staphylococcal specimens were recovered from various diagnostic laboratories in Karachi City, Pakistan. Phenotypic existence of methicillin resistance in S. aureus was observed to be 51.7%. In contrast, when organisms were subjected for amplification of mecA gene by PCR, mecA positive isolates were 36/104 (35%) MRSA isolates. Current work raise question towards the usefulness of molecular identification of mecA gene in confirmation of methicillin resistance without correlating with conventional methods. Therefore, it is essential to consider the other possible resistance mechanisms for β-lactams that may interact with mecA gene in the development of methicillin resistance mechanism in Staphylococcus.
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Affiliation(s)
- Tuba Siddiqui
- Department of Pharmaceutics, Faculty of Pharmacy & Pharmaceutical Sciences, University of Karachi, Karachi, Pakistan
| | - Iyad Naeem Muhammad
- Department of Pharmaceutics, Faculty of Pharmacy & Pharmaceutical Sciences, University of Karachi, Karachi, Pakistan
| | | | - Sakina Fatima
- Department of Pharmaceutics, Faculty of Pharmacy, Jinnah University for Women, Karachi, Pakistan
| | - Nausheen Alam
- Department of Pharmaceutics, Faculty of Pharmacy, Federal Urdu University, Karachi, Pakistan
| | - Rida Masood
- Department of Pharmaceutics, Faculty of Pharmacy & Pharmaceutical Sciences, University of Karachi, Karachi, Pakistan
| | - Rehana Saeed
- Department of Pharmaceutics, Faculty of Pharmacy & Pharmaceutical Sciences, University of Karachi, Karachi, Pakistan
| | - Ghazala Raza Naqvi
- Department of Pharmaceutics, Faculty of Pharmacy, Federal Urdu University, Karachi, Pakistan
| | - Talat Naqvi
- Department of Pharmaceutics, Faculty of Pharmacy & Pharmaceutical Sciences, University of Karachi, Karachi, Pakistan
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Shah DA, Wasim S, Abdullah FE. Comparison of Oxacillin and Cefoxitin for the Detection of mecAGene to Determine Methicillin Resistance in Coagulase Negative Staphylococci(CoNs). J Coll Physicians Surg Pak 2017; 27:520-522. [PMID: 28903850] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Accepted: 08/17/2017] [Indexed: 06/07/2023]
Abstract
The aim of the study was to compare the effectiveness of Cefoxitin with that of Methicillin/Oxacillin in the determination of mecAgene in Methicillin resistant Coagulase-negative staphylococci(CoNS). We assessed 57 CoNS isolates for mecA gene via PCR, which were subsequently subjected to Methicillin/Oxacillin and Cefoxitin disc diffusion test. These methods are simple, inexpensive and easily available compared to PCR despite less specificity. Out of 41 mecApositive species, 33 (80.5%) were resistant to Methicillin/Oxacillin. Cefoxitin-resistance was seen in all 41 (100%) mecApositive samples. Two (12.5%) mecAnegative isolates of S.saprophyticuswere Methicillin/Oxacillin resistant, but were Cefoxitin sensitive. Four (9.7%) isolates of S.saprophyticus, three (7.3%) of S.epidermidisspecies, and one (2.4%) S.haemolyticusthat were mecApositive were sensitive to Methicillin/Oxacillin but resistant to Cefoxitin. Cefoxitin resistance provides a more accurate picture of mecAgene positivity as compared to Methicillin and Oxacillin.
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Affiliation(s)
| | - Shehnaz Wasim
- Medical Student, Ziauddin University, Clifton, Karachi
| | - Farhan Essa Abdullah
- Department of Microbiology, Dr. Essa Laboratory and Diagnostic Centre, North Nazimabad, Karachi
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Duran N, Yildirim Y, Duran GG, Pasa O, Kilinc C, Yildirim I, Eryilmaz N, Bayraktar S. Virulence Factors in Staphylococci Isolated From Nasal Cavities of Footballers. Am J Med Sci 2016; 351:279-85. [PMID: 26992257 DOI: 10.1016/j.amjms.2015.12.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Accepted: 11/05/2015] [Indexed: 11/17/2022]
Abstract
AIM This study aimed to investigate the rate of Panton-Valentine Leukocidin producing Staphylococcus aureus and methicillin (mecA) and slime (icaA/icaD) genes in staphylococcal strains isolated from nasal cavities of footballers. MATERIALS AND METHODS Nasal swab samples were taken from each footballers and a healthy control group for the isolation of staphylococcal strains. The polymerase chain reaction technique was used to determine Panton-Valentine Leukocidin, mecA and icaA/icaD genes in staphylococcal isolates. RESULTS Among 91 S. aureus strains, the presence of mecA gene was detected as 9.9%. This ratio was 17.9% (27 of 151) among the coagulase-negative staphylococci. A significant difference was found between coagulase-negative staphylococci and S. aureus isolates regarding the presence of mecA gene (P < 0.001). As for the genes of the slime, icaA/icaD genes were detected in 198 of 242 (81.8%) strains. The occurrence of slime genes was 91.2% and 89.4% among the S. aureus coagulase and negative staphylococci, respectively (P > 0.05). There was a statistically significant difference between the frequency of the mecA and slime genes when compared with the healthy control group and the football players (P < 0.01). Of 91 isolates, 22 were found to be methicillin resistant by the oxacillin disc diffusion method, whereas the remaining (220) were methicillin susceptible. Methicillin resistance was detected as 14.9% by the polymerase chain reaction method, whereas it was found as 9.1% by phenotypic methods. CONCLUSIONS Early and accurate diagnosis of virulent staphylococcal strains is crucial because the virulent coagulase-negative and coagulase-positive staphylococcal strains in the nasal floras of footballers may be major potential sources of superficial and deep tissue infections.
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Affiliation(s)
- Nizami Duran
- Department of Medical Microbiology, Mustafa Kemal University, İskenderun, Hatay, Türkiye.
| | - Yunus Yildirim
- Physical Education and Sport High School, Mustafa Kemal University, Antakya, Hatay, Türkiye
| | - Gulay Gulbol Duran
- Department of Medical Biology and Genetics, Health College, Mustafa Kemal University, Antakya, Hatay, Türkiye
| | - Ozgur Pasa
- Department of Medical Microbiology, Mustafa Kemal University, İskenderun, Hatay, Türkiye
| | - Cetin Kilinc
- Department of Medical Microbiology, Mustafa Kemal University, İskenderun, Hatay, Türkiye
| | - Irfan Yildirim
- Physical Education and Sport High School, Afyon Kocatepe University, Afyon, Türkiye
| | - Naciye Eryilmaz
- Department of Medical Microbiology, Mustafa Kemal University, İskenderun, Hatay, Türkiye
| | - Suphi Bayraktar
- Department of Medical Microbiology, Mustafa Kemal University, İskenderun, Hatay, Türkiye
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An YD, Du QZ, Tong LY, Yu ZW, Gong XW. Cloning, expression and purification of penicillin-binding protein 3 from Pseudomonas aeruginosa CMCC 10104. Protein Expr Purif 2014; 110:37-42. [PMID: 25514204 DOI: 10.1016/j.pep.2014.12.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2014] [Revised: 12/05/2014] [Accepted: 12/07/2014] [Indexed: 11/18/2022]
Abstract
Penicillin-binding protein 3 (PBP3) of Pseudomonas aeruginosa is the primary target of β-lactams used to treat pseudomonas infections. Meanwhile, structure change and overproduction of PBP3 play important roles in the drug resistance of P. aeruginosa. Therefore, studies on the gene and structure of PBP3 are urgently needed. P. aeruginosa CMCC 10104 is a type culture strain common used in China. However, there is no report on its genomic and proteomic profiles. In this study, based on ftsI of P. aeruginosa PAO1, the gene encoding PBP3 was cloned from CMCC 10104. A truncated version of the ftsI gene, omitting the bases encoding the hydrophobic leader peptide (amino acids 1-34), was amplified by PCR. The cloned DNA shared 99.76% identity with ftsI from PAO1. Only four bases were different (66 C-A, 1020 T-C, 1233 T-C, and 1527 T-C). However, there were no differences between their deduced amino acid sequences. The recombinant PBP3 (rPBP3), containing a 6-histidine tag, was expressed in Escherichia coli BL21 (DE3). Immobilized metal affinity chromatography (IMAC) with Ni(2+)-NTA agarose was used for its purification. The purified rPBP3 was identified by SDS-PAGE and western blot analysis, and showed a single band at about 60kDa with purity higher than 95%. The penicillin-binding assay indicated that the obtained rPBP3 was functional and not hindered by the presence of the C-terminal His-tag. The protocol described in this study offers a method for obtaining purified recombinant PBP3 from P. aeruginosa CMCC 10104.
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Affiliation(s)
- Yan Dong An
- College of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou 310018, China
| | - Qi Zhen Du
- Zhejiang A&F University, Hangzhou 311300, China
| | - Li Yan Tong
- College of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou 310018, China
| | - Zhao Wu Yu
- College of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou 310018, China
| | - Xing Wen Gong
- College of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou 310018, China.
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Sauvage E, Derouaux A, Fraipont C, Joris M, Herman R, Rocaboy M, Schloesser M, Dumas J, Kerff F, Nguyen-Distèche M, Charlier P. Crystal structure of penicillin-binding protein 3 (PBP3) from Escherichia coli. PLoS One 2014; 9:e98042. [PMID: 24875494 PMCID: PMC4038516 DOI: 10.1371/journal.pone.0098042] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Accepted: 04/28/2014] [Indexed: 11/24/2022] Open
Abstract
In Escherichia coli, penicillin-binding protein 3 (PBP3), also known as FtsI, is a central component of the divisome, catalyzing cross-linking of the cell wall peptidoglycan during cell division. PBP3 is mainly periplasmic, with a 23 residues cytoplasmic tail and a single transmembrane helix. We have solved the crystal structure of a soluble form of PBP3 (PBP357–577) at 2.5 Å revealing the two modules of high molecular weight class B PBPs, a carboxy terminal module exhibiting transpeptidase activity and an amino terminal module of unknown function. To gain additional insight, the PBP3 Val88-Ser165 subdomain (PBP388–165), for which the electron density is poorly defined in the PBP3 crystal, was produced and its structure solved by SAD phasing at 2.1 Å. The structure shows a three dimensional domain swapping with a β-strand of one molecule inserted between two strands of the paired molecule, suggesting a possible role in PBP357–577 dimerization.
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Affiliation(s)
- Eric Sauvage
- Centre d’Ingénierie des Protéines, Université de Liège, Institut de Physique B5a et Institut de Chimie B6a, Sart Tilman, Liège, Belgium
- * E-mail:
| | - Adeline Derouaux
- Centre d’Ingénierie des Protéines, Université de Liège, Institut de Physique B5a et Institut de Chimie B6a, Sart Tilman, Liège, Belgium
| | - Claudine Fraipont
- Centre d’Ingénierie des Protéines, Université de Liège, Institut de Physique B5a et Institut de Chimie B6a, Sart Tilman, Liège, Belgium
| | - Marine Joris
- Centre d’Ingénierie des Protéines, Université de Liège, Institut de Physique B5a et Institut de Chimie B6a, Sart Tilman, Liège, Belgium
| | - Raphaël Herman
- Centre d’Ingénierie des Protéines, Université de Liège, Institut de Physique B5a et Institut de Chimie B6a, Sart Tilman, Liège, Belgium
| | - Mathieu Rocaboy
- Centre d’Ingénierie des Protéines, Université de Liège, Institut de Physique B5a et Institut de Chimie B6a, Sart Tilman, Liège, Belgium
| | - Marie Schloesser
- Centre d’Ingénierie des Protéines, Université de Liège, Institut de Physique B5a et Institut de Chimie B6a, Sart Tilman, Liège, Belgium
| | - Jacques Dumas
- Sanofi R&D, protein production, 13 quai Jules Guesde, 94403 Vitry sur Seine, France
| | - Frédéric Kerff
- Centre d’Ingénierie des Protéines, Université de Liège, Institut de Physique B5a et Institut de Chimie B6a, Sart Tilman, Liège, Belgium
| | - Martine Nguyen-Distèche
- Centre d’Ingénierie des Protéines, Université de Liège, Institut de Physique B5a et Institut de Chimie B6a, Sart Tilman, Liège, Belgium
| | - Paulette Charlier
- Centre d’Ingénierie des Protéines, Université de Liège, Institut de Physique B5a et Institut de Chimie B6a, Sart Tilman, Liège, Belgium
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Cha HJ, Jeong JH, Kim YG. Crystallization and preliminary X-ray crystallographic analysis of PBPD2 from Listeria monocytogenes. Acta Crystallogr F Struct Biol Commun 2014; 70:535-7. [PMID: 24699757 PMCID: PMC3976081 DOI: 10.1107/s2053230x14005470] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2013] [Accepted: 03/10/2014] [Indexed: 02/05/2023] Open
Abstract
Penicillin-binding proteins (PBPs), which mediate the peptidoglycan biosynthetic pathway in the bacterial cell wall, have been intensively investigated as a target for the design of antibiotics. In this study, PBPD2, a low-molecular-weight PBP encoded by lmo2812 from Listeria monocytogenes, was overexpressed in Escherichia coli, purified and crystallized at 295 K using the sitting-drop vapour-diffusion method. The crystal belonged to the primitive orthorhombic space group P212121, with unit-cell parameters a = 37.7, b = 74.7, c = 75.1 Å, and diffracted to 1.55 Å resolution. There was one molecule in the asymmetric unit. The preliminary structure was determined by the molecular-replacement method.
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Affiliation(s)
- Hyung Jin Cha
- Pohang Accelerator Laboratory, Pohang University of Science and Technology, Pohang 790-784, Republic of Korea
| | - Jae-Hee Jeong
- Pohang Accelerator Laboratory, Pohang University of Science and Technology, Pohang 790-784, Republic of Korea
| | - Yeon-Gil Kim
- Pohang Accelerator Laboratory, Pohang University of Science and Technology, Pohang 790-784, Republic of Korea
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Zhang X, Paganelli FL, Bierschenk D, Kuipers A, Bonten MJM, Willems RJL, van Schaik W. Genome-wide identification of ampicillin resistance determinants in Enterococcus faecium. PLoS Genet 2012; 8:e1002804. [PMID: 22761597 PMCID: PMC3386183 DOI: 10.1371/journal.pgen.1002804] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2012] [Accepted: 05/17/2012] [Indexed: 01/03/2023] Open
Abstract
Enterococcus faecium has become a nosocomial pathogen of major importance, causing infections that are difficult to treat owing to its multi-drug resistance. In particular, resistance to the β-lactam antibiotic ampicillin has become ubiquitous among clinical isolates. Mutations in the low-affinity penicillin binding protein PBP5 have previously been shown to be important for ampicillin resistance in E. faecium, but the existence of additional resistance determinants has been suggested. Here, we constructed a high-density transposon mutant library in E. faecium and developed a transposon mutant tracking approach termed Microarray-based Transposon Mapping (M-TraM), leading to the identification of a compendium of E. faecium genes that contribute to ampicillin resistance. These genes are part of the core genome of E. faecium, indicating a high potential for E. faecium to evolve towards β-lactam resistance. To validate the M-TraM results, we adapted a Cre-lox recombination system to construct targeted, markerless mutants in E. faecium. We confirmed the role of four genes in ampicillin resistance by the generation of targeted mutants and further characterized these mutants regarding their resistance to lysozyme. The results revealed that ddcP, a gene predicted to encode a low-molecular-weight penicillin binding protein with D-alanyl-D-alanine carboxypeptidase activity, was essential for high-level ampicillin resistance. Furthermore, deletion of ddcP sensitized E. faecium to lysozyme and abolished membrane-associated D,D-carboxypeptidase activity. This study has led to the development of a broadly applicable platform for functional genomic-based studies in E. faecium, and it provides a new perspective on the genetic basis of ampicillin resistance in this organism. Enterococcus faecium has emerged as an important nosocomial pathogen around the world. Clinical E. faecium isolates are often resistant to multiple antibiotics, thereby complicating therapeutic interventions. However, the molecular mechanisms that contribute to the recent emergence of E. faecium as a nosocomial pathogen of major importance are only poorly understood, which is, at least partially, due to the lack of appropriate genetic tools for the study of this organism. Here, we developed a systematic genome-wide strategy, based on transposon mutagenesis and microarray-based screening, to identify E. faecium genes that contribute to ampicillin resistance. We also adapted the Cre-lox recombination system to construct targeted, markerless mutants in E. faecium. These tools enabled us to perform both high-throughput genome-wide analysis and specific targeted investigations in a clinical E. faecium isolate. We comprehensively identified, confirmed, and characterized a compendium of genes affecting the sensitivity to ampicillin in E. faecium. The identified intrinsic ampicillin resistance determinants are highly conserved among E. faecium, indicating that this organism has a high potential to evolve towards ampicillin resistance. These ampicillin-resistance determinants may serve as targets for the development of novel antimicrobial therapeutics.
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Affiliation(s)
- Xinglin Zhang
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Fernanda L. Paganelli
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Damien Bierschenk
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Annemarie Kuipers
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Marc J. M. Bonten
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Rob J. L. Willems
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Willem van Schaik
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands
- * E-mail:
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10
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Ochiai S, Sekiguchi S, Hayashi A, Shimadzu M, Ishiko H, Matsushima-Nishiwaki R, Kozawa O, Yasuda M, Deguchi T. Decreased affinity of mosaic-structure recombinant penicillin-binding protein 2 for oral cephalosporins in Neisseria gonorrhoeae. J Antimicrob Chemother 2007; 60:54-60. [PMID: 17540669 DOI: 10.1093/jac/dkm166] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
OBJECTIVES In Neisseria gonorrhoeae, the mosaic structure of penicillin-binding protein 2 (PBP 2), composed of fragments of PBP 2 from Neisseria cinerea and Neisseria perflava, was significantly associated with decreased susceptibility to cephalosporins, particularly oral cephalosporins. The aim of this study was to determine the affinity of mosaic PBP 2 for cephalosporins in N. gonorrhoeae. METHODS Two types of non-mosaic PBP 2 from the type strain of N. gonorrhoeae (ATCC 19424) and a clinical strain (GU01-29), as well as the mosaic PBP 2 from a clinical strain (GU01-89), were expressed in insect cells, and recombinant PBP 2s were purified. ATCC 19424 and GU01-29 were susceptible to cephalosporins. GU01-89 showed decreased susceptibility to cephalosporins. Bindings of fluorescent penicillin to PBP 2 were characterized by the Scatchard plot analysis. The affinity of the recombinant PBP 2s for cefdinir, cefixime and ceftriaxone was determined by PBP 2 competition assays with fluorescent penicillin. RESULTS The K(d) value of mosaic PBP 2 for fluorescent penicillin was higher than that of non-mosaic PBP 2s. The affinity of mosaic PBP 2 for cefdinir or cefixime was lower than that of the non-mosaic PBP 2s. The affinity of the mosaic PBP 2 for ceftriaxone was not changed, compared with that of the non-mosaic PBP 2s. CONCLUSIONS Other mechanisms may be involved in clinical isolates with decreased susceptibility to cephalosporins, but this study suggests that the decreased affinity of mosaic-structure recombinant PBP 2 for oral cephalosporins may contribute to decreased susceptibility to these antibiotics in N. gonorrhoeae.
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Affiliation(s)
- Susumu Ochiai
- Research and Development Department, Mitsubishi Kagaku Bio-Clinical Laboratories, Inc., 3-30-1 Shimura, Itabashi-Ku, Tokyo 174-8555, Japan.
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Hanselman BA, Kruth SA, Rousseau J, Low DE, Willey BM, McGeer A, Weese JS. Methicillin-resistant Staphylococcus aureus colonization in veterinary personnel. Emerg Infect Dis 2007; 12:1933-8. [PMID: 17326947 PMCID: PMC3291342 DOI: 10.3201/eid1212.060231] [Citation(s) in RCA: 116] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
TOC Summary: Prevalence of colonization was 6.5%, and employment within a large-animal practice was a significant risk factor. Methicillin-resistant Staphylococcus aureus (MRSA) was isolated from nares of 27/417 (6.5%) attendees at an international veterinary conference: 23/345 (7.0%) veterinarians, 4/34 (12.0%) technicians, and 0/38 others. Colonization was more common for large-animal (15/96, 15.6%) than small-animal personnel (12/271, 4.4%) or those with no animal patient contact (0/50) (p<0.001). Large-animal practice was the only variable significantly associated with colonization (odds ratio 2.9; 95% confidence interval 1.2–6.6). Pulsed-field gel electrophoresis identified 2 predominant clones with similar distribution among veterinarians as previously reported for horses and companion animals. Canadian epidemic MRSA-2 (CMRSA) was isolated from 11 small-animal and 2 large-animal personnel from the United States (n = 12) and Germany (n = 1). In contrast, CMRSA-5 was isolated exclusively from large-animal personnel (p<0.001) in the United States (n = 10), United Kingdom (n = 2), and Denmark (n = 1). MRSA colonization may be an occupational risk for veterinary professionals.
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Affiliation(s)
- Beth A Hanselman
- Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada.
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Legaree BA, Daniels K, Weadge JT, Cockburn D, Clarke AJ. Function of penicillin-binding protein 2 in viability and morphology of Pseudomonas aeruginosa. J Antimicrob Chemother 2007; 59:411-24. [PMID: 17289762 DOI: 10.1093/jac/dkl536] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
OBJECTIVES To investigate the function of penicillin-binding protein 2 (PBP 2) in Pseudomonas aeruginosa PAO1. METHODS The growth and morphology of P. aeruginosa cultured in the absence and presence of mecillinam was assessed. The gene encoding PBP 2, pbpA, was identified in the genome of P. aeruginosa PAO1 and both its full-length and an engineered truncated form were cloned and expressed in Escherichia coli. Site-directed mutagenesis was used to confirm Ser-327 as the catalytic nucleophile of its transpeptidase domain. Allelic exchange was used to construct a chromosomal mutant of pbpA in strain PAO1. RESULTS PAO1 grew with a spherical morphology in the presence of mecillinam at concentrations as high as 2000 mg/L. Both wild-type and truncated, soluble forms of PBP 2 were shown to bind penicillins and a competition assay demonstrated their specificity for mecillinam. The PAO1 DeltapbpA insertional mutant also grew as spheres, and complementation with a plasmid encoding active pbpA, but not with an inactive Ser-327 --> Ala derivative, restored rod-shape morphology. MIC values of a variety of beta-lactams were significantly lower for the insertional mutant compared with wild-type PAO1. The muropeptide profile of peptidoglycan from PAO1 DeltapbpA analysed by HPLC/MALDI TOF MS indicated wild-type levels of cross-linking despite the loss of PBP 2 transpeptidase activity. CONCLUSIONS PBP 2 in P. aeruginosa is responsible for the rod-shape morphology of the cells and contributes significantly to beta-lactam resistance. The viability of cells lacking an active PBP 2 suggests that the organization of the peptidoglycan biosynthetic machinery is different in this pathogen compared with E. coli.
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Affiliation(s)
- Blaine A Legaree
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1 Canada
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Carapito R, Gallet B, Zapun A, Vernet T. Automated high-throughput process for site-directed mutagenesis, production, purification, and kinetic characterization of enzymes. Anal Biochem 2006; 355:110-6. [PMID: 16797473 DOI: 10.1016/j.ab.2006.04.047] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2006] [Revised: 04/12/2006] [Accepted: 04/26/2006] [Indexed: 10/24/2022]
Abstract
Site-directed mutagenesis followed by functional characterization is a widely used approach to obtain information on the structure-function relationship of proteins. Due to time and cost considerations, the number of amino acids studied is frequently reduced. To address the need for convenient parallel production of numerous point mutants of a protein, we developed an automated method to perform classical site-directed mutagenesis, protein purification, and characterization in a high-throughput manner. The process consists of a succession of six fully automated protocols that can be adapted to any automated liquid handling systems. Our procedure allows construction, validation, and characterization of hundreds of site-directed mutants of a given protein in just 4 days. The method is especially adapted to projects aiming at the study of unique or multiple mutants without the need to construct and screen large libraries of random mutants. The usefulness of the technique is illustrated by the construction and characterization of tens of single mutants of the penicillin-binding protein 2x (PBP2x) from Streptococcus pneumoniae. Moreover, seven mutations of PBP2x were obtained simultaneously in a single experiment with efficiency close to 90%.
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Affiliation(s)
- Raphaël Carapito
- Laboratoire d'Ingénierie des Macromolécules, Institut de Biologie Structurale (CEA/CNRS UMR 5075/UJF), Grenoble Cedex 1 F-38027, France
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Yoshida H, Hensgens CMH, van der Laan JM, Sutherland JD, Hart DJ, Dijkstra BW. An approach to prevent aggregation during the purification and crystallization of wild type acyl coenzyme A: isopenicillin N acyltransferase from Penicillium chrysogenum. Protein Expr Purif 2005; 41:61-7. [PMID: 15802222 DOI: 10.1016/j.pep.2005.02.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2004] [Revised: 02/01/2005] [Indexed: 11/19/2022]
Abstract
Acyl coenzyme A: isopenicillin N acyltransferase (AT) from Penicillium chrysogenum is an enzyme of interest for the biosynthesis of beta-lactam antibiotics. Severe aggregation problems with wild type AT have, however, prevented significant progress in the structure-function analysis of this enzyme for a decade. In this study, we show an approach to solve this aggregation problem by using dynamic light scattering (DLS) analysis to probe the aggregation state of the protein in the presence of various additives. After a one-step purification of recombinant wild type AT with a C-terminal His-tag using Ni2+ affinity chelate chromatography, addition of a combination of 5 mM DTT, 250 mM NaCl, and 5 mM EDTA to the purified AT effectively prevented aggregation. In the presence of these additives, the DLS profile of AT shows a narrow size distribution indicative of a homogeneous protein solution and the absence of aggregation. The purity and mono-dispersity of wild type AT was sufficient for the growth of high quality crystals diffracting to 1.64 A resolution.
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Affiliation(s)
- Hiromi Yoshida
- Laboratory of Biophysical Chemistry, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands
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