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Liu H, Wu YQ, Chen LP, Gao X, Huang HN, Qiu FL, Wu DC. Biofilm-Related Genes: Analyses in Multi-Antibiotic Resistant Acinetobacter Baumannii Isolates From Mainland China. Med Sci Monit 2016; 22:1801-7. [PMID: 27234982 PMCID: PMC4913728 DOI: 10.12659/msm.898959] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Acinetobacter baumannii is an important nosocomial pathogen which shows a high level of mortality risk. Several papers have reported biofilm formation as a well-known pathogenic mechanism in A. baumannii infections and exceptional antibiotic resistance. The study aims to explore the potential relationships between biofilm-related genes and antimicrobial resistance. MATERIAL AND METHODS Samples from 122 patients with lower respiratory tract infections of A. baumannii were collected at Fujian Longyan First Hospital from January 2013 to September 2014. A. baumannii was isolated from sputum specimens. Biofilm-related genes including abaI, csuE, ompA, and bla-PER1 were analyzed by PCR. The minimum inhibitory concentration method was used to determine the sensitivity of each strain to antibiotics. RESULTS The clinical manifestations of A. baumannii-induced lower respiratory tract infections lacked specificity. Infected patients were most commonly admitted to intensive care units (54.9%) and frequently had chronic obstructive pulmonary disease (27.0%). The detection rates of abaI and csuE were both 59.8%, and those of ompA and bla-PER1 were 100% and 0%, respectively. After genetic testing, antimicrobial resistance to amikacin, ampicillin/sulbactam, and 14 other types of antimicrobials was higher in abaI- and csuE-positive strains than in abaI- and csuE-negative strains (P<0.05). CONCLUSIONS The findings of our study suggest that abaI- and csuE-positive Acinetobacter baumannii strains are associated with a higher incidence of antibiotic resistance in 14 types of antimicrobials.
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Affiliation(s)
- Hui Liu
- Department of Clinical Laboratory, Fujian Longyan First Hospital, Longyan First Affiliated Hospital of Fujian Medical University, Longyan, Fujian, China (mainland)
| | - Yong-Quan Wu
- Department of Respiration, Fujian Longyan First Hospital, Longyan First Affiliated Hospital of Fujian Medical University, Longyan, Fujian, China (mainland)
| | - Li-Ping Chen
- Department of Clinical Laboratory, Fujian Longyan First Hospital, Longyan First Affiliated Hospital of Fujian Medical University, Longyan, Fujian, China (mainland)
| | - Xiang Gao
- Intensive Care Unit, Fujian Longyan First Hospital, Longyan First Affiliated Hospital of Fujian Medical University, Longyan, Fujian, China (mainland)
| | - Hao-Nan Huang
- Department of Clinical Laboratory, Fujian Longyan First Hospital, Longyan First Affiliated Hospital of Fujian Medical University, Longyan, Fujian, China (mainland)
| | - Fu-Lan Qiu
- Department of Clinical Laboratory, Fujian Longyan First Hospital, Longyan First Affiliated Hospital of Fujian Medical University, Longyan, Fujian, China (mainland)
| | - Ding-Chang Wu
- Department of Clinical Laboratory, Fujian Longyan First Hospital, Longyan First Affiliated Hospital of Fujian Medical University, Longyan, Fujian, China (mainland)
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202
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Clinical and Epidemiological Significance of Carbapenem Resistance in Acinetobacter baumannii Infections. Antimicrob Agents Chemother 2016; 60:3127-31. [PMID: 26883694 DOI: 10.1128/aac.02656-15] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Accepted: 02/07/2016] [Indexed: 02/07/2023] Open
Abstract
Carbapenems are considered the treatment of choice for Acinetobacter baumannii infections. Many facilities implement preventive measures toward only carbapenem-resistant A. baumannii (CRAB). However, the independent role of the carbapenem resistance determinant on patient outcomes remains controversial. In a 6-year analysis of adults with A. baumannii bloodstream infection (BSI), the outcomes of 149 CRAB isolates were compared to those of 91 patients with carbapenem-susceptible A. baumannii In bivariable analyses, CRAB BSIs were significantly associated with worse outcomes and with a delay in the initiation of appropriate antimicrobial therapy (DAAT). However, in multivariable analyses, carbapenem resistance status was no longer associated with poor outcomes, while DAAT remained an independent predictor. The epidemiological significance of A. baumannii should not be determined by its resistance to carbapenems.
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203
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Chang L, Wang J, Tong C, Zhao L, Liu X. Comparison of antimicrobial activities of polyacrylonitrile fibers modified with quaternary phosphonium salts having different alkyl chain lengths. J Appl Polym Sci 2016. [DOI: 10.1002/app.43689] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Li Chang
- College of Chemistry and Chemical Engineering; Hunan University; Changsha Hunan 410082 China
| | - Jing Wang
- Henan Institute of Chemistry; Henan Academy of Sciences; Zhengzhou Henan 450002 China
| | - Chunyi Tong
- College of Chemistry and Chemical Engineering; Hunan University; Changsha Hunan 410082 China
- Hunan Province Key Laboratory of Plant Functional Genomics and Developmental Regulation; College of Biology, Hunan University; Changsha 410082 China
| | - Liang Zhao
- Henan Institute of Chemistry; Henan Academy of Sciences; Zhengzhou Henan 450002 China
| | - Xuanming Liu
- College of Chemistry and Chemical Engineering; Hunan University; Changsha Hunan 410082 China
- Hunan Province Key Laboratory of Plant Functional Genomics and Developmental Regulation; College of Biology, Hunan University; Changsha 410082 China
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204
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Luo A, Zhong Z, Wan Q, Ye Q. The Distribution and Resistance of Pathogens Among Solid Organ Transplant Recipients with Pseudomonas aeruginosa Infections. Med Sci Monit 2016; 22:1124-30. [PMID: 27045418 PMCID: PMC4824462 DOI: 10.12659/msm.896026] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Background Pseudomonas aeruginosa infection remains a life-threatening complication after solid organ transplantation (SOT). We aimed to investigate the distribution and drug susceptibility of pathogens, and clinical characteristics of SOT recipients with Pseudomonas aeruginosa infections. Material/Methods A total of 55 SOT recipients who developed 61 episodes of Pseudomonas aeruginosa infections between January 1, 2003 and July 31, 2015 were retrospectively analyzed. The distribution and the drug susceptibility of Pseudomonas aeruginosa were reviewed. Results The most common site from which 61 Pseudomonas aeruginosa rods were isolated were the lungs (57.4%, n=37), followed by the blood (27.9%, n=17). There were 35, 18, and 9 recipients accompanied with a serum creatinine level of >1.5 mg/dL, lymphocyte count of <300/mm3, and a serum albumin level of <30 g/L, respectively. Seven patients each presented with white blood cell count of >15 000/mm3 and platelet count of <50 000/mm3. There were 6 (10.9%) cases of septic shocks and 18 (32.7%) deaths. Antibiotic resistance rate of all Pseudomonas aeruginosa to 4 of 10 antibiotics investigated was more than 50%. Of these 61 Pseudomonas aeruginosa isolates, 47.5% were carbapenem-resistant. The rods were relatively sensitive to piperacillin-tazobactam, levofloxacin, amikacin, and cefoperazone-sulbactam (resistance rate <40%). Conclusions The clinical presentation of Pseudomonas aeruginosa infections included high body temperature, decreased platelet count, elevated white blood cell count, a high nosocomial origin and mortality, and onset in the late period after transplantation. According to our findings, piperacillin-tazobactam, levofloxacin, amikacin, and cefoperazone-sulbactam, alone or combination, are recommended to treat SOT recipients with Pseudomonas aeruginosa infections.
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Affiliation(s)
- Aijing Luo
- Key Laboratory of Medical Information Research (Central South University), College ofHunan Province, Changsha, China (mainland)
| | - Zhuqing Zhong
- Department of nursing, The Third Xiangya Hospital, Central South University, Changsha, China (mainland)
| | - Qiquan Wan
- Department of Transplant Surgery, the Third Xiangya Hospital, Central South University, Changsha, China (mainland)
| | - Qifa Ye
- Department of Transplant Surgery, The Third Xiangya Hospital, Central South University, Changsha, China (mainland)
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205
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O’Donnell JN, Miglis CM, Lee JY, Tuvell M, Lertharakul T, Scheetz MH. Carbapenem susceptibility breakpoints, clinical implications with the moving target. Expert Rev Anti Infect Ther 2016; 14:389-401. [DOI: 10.1586/14787210.2016.1159131] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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206
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Davodian E, Sadeghifard N, Ghasemian A, Noorbakhsh S. Presence of blaPER-1 and blaVEB-1 beta-lactamase genes among isolates of Pseudomonas aeruginosa from South West of Iran. J Epidemiol Glob Health 2016; 6:211-3. [PMID: 26944896 PMCID: PMC7320475 DOI: 10.1016/j.jegh.2016.02.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Revised: 12/18/2015] [Accepted: 02/12/2016] [Indexed: 11/06/2022] Open
Abstract
Pseudomonas aeruginosa isolates have acquired resistance to antibiotics such as novel beta-lactams. The aim of this study was to investigate the blaPER-1, blaVEB-1, and blaPSE-1 genes among isolates of P. aeruginosa among intensive care unit (ICU) patients. Sixty-five isolates were collected. The antibiotic susceptibility testing and combined disk tests were performed to detect the isolates producing extended spectrum beta-lactamases (ESBLs) among ceftazidime-resistant isolates. Polymerase chain reaction (PCR) amplification of blaPER-1, blaVEB-1, and blaPSE-1 genes was conducted. Ten (15.3%) isolates were ESBL-positive, of which 40% (n = 4) belonged to males and 60% (n = 6) were collected from females. Moreover, two and one isolates harbored blaPER-1 and blaVEB-1 genes, respectively.
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Affiliation(s)
- Elham Davodian
- Department of Microbiology, School of Paramedical Sciences, Ilam University of Medical Sciences, Ilam, Iran.
| | - Nourkhoda Sadeghifard
- Department of Microbiology, Faculty of Medicine, Ilam University of Medical Sciences, Ilam, Iran
| | - Abdolmajid Ghasemian
- Department of Bacteriology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Samileh Noorbakhsh
- Research Center of Pediatric Infectious Diseases, Iran University of Medical Sciences, Tehran, Iran
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207
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Resistome and pathogenomics of multidrug resistant (MDR) Pseudomonas aeruginosa VRFPA03, VRFPA05 recovered from alkaline chemical keratitis and post-operative endophthalmitis patient. Gene 2016; 578:105-11. [DOI: 10.1016/j.gene.2015.12.022] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Accepted: 12/08/2015] [Indexed: 01/11/2023]
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208
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Wang Y, Mi Z, Niu W, An X, Yuan X, Liu H, Li P, Liu Y, Feng Y, Huang Y, Zhang X, Zhang Z, Fan H, Peng F, Tong Y, Bai C. Intranasal treatment with bacteriophage rescues mice from Acinetobacter baumannii-mediated pneumonia. Future Microbiol 2016; 11:631-41. [PMID: 26925593 DOI: 10.2217/fmb.16.11] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
AIM With the emergence of drug-resistant bacteria, finding alternative agents to treat antibiotic-resistant bacterial infections is imperative. MATERIALS & METHODS A mouse pneumonia model was developed by combining cyclophosphamide pretreatment and Acinetobacter baumannii challenge, and a lytic bacteriophage was evaluated for its therapeutic efficacy in this model by examining the survival rate, bacterial load in the lung and lung pathology. RESULTS Intranasal instillation with bacteriophage rescued 100% of mice following lethal challenge with A. baumannii. Phage treatment reduced bacterial load in the lung. Microcomputed tomography indicated a reduction in lung inflammation in mice given phage. CONCLUSION This research demonstrates that intranasal application of bacteriophage is viable, and could provide complete protection from pneumonia caused by A. baumannii.
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Affiliation(s)
- Yong Wang
- Department of Respiratory Medicine, PLA Hospital 307, Beijing 100071, China
| | - Zhiqiang Mi
- State Key Laboratory of Pathogen & Biosecurity, Beijing Institute of Microbiology & Epidemiology, Beijing 100071, China
| | - Wenkai Niu
- Department of Respiratory Medicine, PLA Hospital 307, Beijing 100071, China
| | - Xiaoping An
- State Key Laboratory of Pathogen & Biosecurity, Beijing Institute of Microbiology & Epidemiology, Beijing 100071, China
| | - Xin Yuan
- Department of Respiratory Medicine, PLA Hospital 307, Beijing 100071, China
| | - Huiying Liu
- Department of Respiratory Medicine, PLA Hospital 307, Beijing 100071, China
| | - Puyuan Li
- Department of Respiratory Medicine, PLA Hospital 307, Beijing 100071, China
| | - Yannan Liu
- Department of Respiratory Medicine, PLA Hospital 307, Beijing 100071, China
| | - Yuzhong Feng
- Department of Respiratory Medicine, PLA Hospital 307, Beijing 100071, China
| | - Yong Huang
- State Key Laboratory of Pathogen & Biosecurity, Beijing Institute of Microbiology & Epidemiology, Beijing 100071, China
| | - Xianglilan Zhang
- State Key Laboratory of Pathogen & Biosecurity, Beijing Institute of Microbiology & Epidemiology, Beijing 100071, China
| | - Zhiyi Zhang
- State Key Laboratory of Pathogen & Biosecurity, Beijing Institute of Microbiology & Epidemiology, Beijing 100071, China
| | - Hang Fan
- State Key Laboratory of Pathogen & Biosecurity, Beijing Institute of Microbiology & Epidemiology, Beijing 100071, China
| | - Fan Peng
- Department of Respiratory Medicine, the First Hospital of Changsha, 410000, China
| | - Yigang Tong
- Department of Respiratory Medicine, PLA Hospital 307, Beijing 100071, China
| | - Changqing Bai
- State Key Laboratory of Pathogen & Biosecurity, Beijing Institute of Microbiology & Epidemiology, Beijing 100071, China
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209
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Oliveira H, Vilas Boas D, Mesnage S, Kluskens LD, Lavigne R, Sillankorva S, Secundo F, Azeredo J. Structural and Enzymatic Characterization of ABgp46, a Novel Phage Endolysin with Broad Anti-Gram-Negative Bacterial Activity. Front Microbiol 2016; 7:208. [PMID: 26955368 PMCID: PMC4768612 DOI: 10.3389/fmicb.2016.00208] [Citation(s) in RCA: 103] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2016] [Accepted: 02/08/2016] [Indexed: 12/12/2022] Open
Abstract
The present study demonstrates the antibacterial potential of a phage endolysin against Gram-negative pathogens, particularly against multidrug resistant strains of Acinetobacter baumannii. We have cloned, heterologously expressed and characterized a novel endolysin (ABgp46) from Acinetobacter phage vb_AbaP_CEB1 and tested its antibacterial activity against several multidrug-resistant A. baumannii strains. LC-MS revealed that ABgp46 is an N-acetylmuramidase, that is also active over a broad pH range (4.0-10.0) and temperatures up to 50°C. Interestingly, ABgp46 has intrinsic and specific anti-A. baumannii activity, reducing multidrug resistant strains by up to 2 logs within 2 h. By combining ABgp46 with several organic acids that act as outer membrane permeabilizing agents, it is possible to increase and broaden antibacterial activity to include other Gram-negative bacterial pathogens. In the presence of citric and malic acid, ABgp46 reduces A. baumannii below the detection limit (>5 log) and more than 4 logs Pseudomonas aeruginosa and Salmonella typhimurium strains. Overall, this globular endolysin exhibits a broad and high activity against Gram-negative pathogens, that can be enhanced in presence of citric and malic acid, and be used in human and veterinary medicine.
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Affiliation(s)
- Hugo Oliveira
- Centre of Biological Engineering, Laboratório de Investigação em Biofilmes Rosário Oliveira, University of Minho Braga, Portugal
| | - Diana Vilas Boas
- Centre of Biological Engineering, Laboratório de Investigação em Biofilmes Rosário Oliveira, University of Minho Braga, Portugal
| | - Stéphane Mesnage
- Krebs Institute, Department of Molecular Biology and Biotechnology, University of Sheffield Sheffield, UK
| | - Leon D Kluskens
- Centre of Biological Engineering, Laboratório de Investigação em Biofilmes Rosário Oliveira, University of Minho Braga, Portugal
| | - Rob Lavigne
- Laboratory of Gene Technology, KU Leuven Leuven, Belgium
| | - Sanna Sillankorva
- Centre of Biological Engineering, Laboratório de Investigação em Biofilmes Rosário Oliveira, University of Minho Braga, Portugal
| | - Francesco Secundo
- Istituto di Chimica del Riconoscimento Molecolare - Consiglio Nazionale delle Ricerche Milano, Italy
| | - Joana Azeredo
- Centre of Biological Engineering, Laboratório de Investigação em Biofilmes Rosário Oliveira, University of Minho Braga, Portugal
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210
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Abstract
Carbapenem resistance, mainly among Gram-negative pathogens, is an ongoing public-health problem of global dimensions. This type of antimicrobial resistance, especially when mediated by transferable carbapenemase-encoding genes, is spreading rapidly causing serious outbreaks and dramatically limiting treatment options. In this article, important key points related to carbapenem resistance are reviewed and future perspectives are discussed.
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211
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Patel TS, Cottreau JM, Hirsch EB, Tam VH. Impact of hyperglycemia on outcomes of patients with Pseudomonas aeruginosa bacteremia. Diagn Microbiol Infect Dis 2016; 84:155-8. [DOI: 10.1016/j.diagmicrobio.2015.10.024] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Revised: 10/22/2015] [Accepted: 10/26/2015] [Indexed: 11/16/2022]
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212
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Qin TT, Kang HQ, Ma P, Li PP, Huang LY, Gu B. SOS response and its regulation on the fluoroquinolone resistance. ANNALS OF TRANSLATIONAL MEDICINE 2016; 3:358. [PMID: 26807413 DOI: 10.3978/j.issn.2305-5839.2015.12.09] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Bacteria can survive fluoroquinolone antibiotics (FQs) treatment by becoming resistant through a genetic change-mutation or gene acquisition. The SOS response is widespread among bacteria and exhibits considerable variation in its composition and regulation, which is repressed by LexA protein and derepressed by RecA protein. Here, we take a comprehensive review of the SOS gene network and its regulation on the fluoroquinolone resistance. As a unique survival mechanism, SOS may be an important factor influencing the outcome of antibiotic therapy in vivo.
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Affiliation(s)
- Ting-Ting Qin
- 1 Medical Technology Institute of Xuzhou Medical College, Xuzhou 221004, China ; 2 Department of Laboratory Medicine, Affiliated Hospital of Xuzhou Medical College, Xuzhou 221006, China
| | - Hai-Quan Kang
- 1 Medical Technology Institute of Xuzhou Medical College, Xuzhou 221004, China ; 2 Department of Laboratory Medicine, Affiliated Hospital of Xuzhou Medical College, Xuzhou 221006, China
| | - Ping Ma
- 1 Medical Technology Institute of Xuzhou Medical College, Xuzhou 221004, China ; 2 Department of Laboratory Medicine, Affiliated Hospital of Xuzhou Medical College, Xuzhou 221006, China
| | - Peng-Peng Li
- 1 Medical Technology Institute of Xuzhou Medical College, Xuzhou 221004, China ; 2 Department of Laboratory Medicine, Affiliated Hospital of Xuzhou Medical College, Xuzhou 221006, China
| | - Lin-Yan Huang
- 1 Medical Technology Institute of Xuzhou Medical College, Xuzhou 221004, China ; 2 Department of Laboratory Medicine, Affiliated Hospital of Xuzhou Medical College, Xuzhou 221006, China
| | - Bing Gu
- 1 Medical Technology Institute of Xuzhou Medical College, Xuzhou 221004, China ; 2 Department of Laboratory Medicine, Affiliated Hospital of Xuzhou Medical College, Xuzhou 221006, China
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213
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Rezaee D, Zarrini G, Ahangarzadeh Rezaee M. Correlation Between ISAba1 Upstream ampC Gene and Resistance to Cefotaxime in Acinetobacter baumannii: A Serious Threat to Nosocomial Infections. ACTA ACUST UNITED AC 2016. [DOI: 10.17795/ajcmi-32417] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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214
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Lean SS, Yeo CC, Suhaili Z, Thong KL. Comparative Genomics of Two ST 195 Carbapenem-Resistant Acinetobacter baumannii with Different Susceptibility to Polymyxin Revealed Underlying Resistance Mechanism. Front Microbiol 2016; 6:1445. [PMID: 26779129 PMCID: PMC4700137 DOI: 10.3389/fmicb.2015.01445] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 12/03/2015] [Indexed: 01/19/2023] Open
Abstract
Acinetobacter baumannii is a Gram-negative nosocomial pathogen of importance due to its uncanny ability to acquire resistance to most antimicrobials. These include carbapenems, which are the drugs of choice for treating A. baumannii infections, and polymyxins, the drugs of last resort. Whole genome sequencing was performed on two clinical carbapenem-resistant A. baumannii AC29 and AC30 strains which had an indistinguishable ApaI pulsotype but different susceptibilities to polymyxin. Both genomes consisted of an approximately 3.8 Mbp circular chromosome each and several plasmids. AC29 (susceptible to polymyxin) and AC30 (resistant to polymyxin) belonged to the ST195 lineage and are phylogenetically clustered under the International Clone II (IC-II) group. An AbaR4-type resistance island (RI) interrupted the comM gene in the chromosomes of both strains and contained the bla OXA-23 carbapenemase gene and determinants for tetracycline and streptomycin resistance. AC29 harbored another copy of bla OXA-23 in a large (~74 kb) conjugative plasmid, pAC29b, but this gene was absent in a similar plasmid (pAC30c) found in AC30. A 7 kb Tn1548::armA RI which encodes determinants for aminoglycoside and macrolide resistance, is chromosomally-located in AC29 but found in a 16 kb plasmid in AC30, pAC30b. Analysis of known determinants for polymyxin resistance in AC30 showed mutations in the pmrA gene encoding the response regulator of the two-component pmrAB signal transduction system as well as in the lpxD, lpxC, and lpsB genes that encode enzymes involved in the biosynthesis of lipopolysaccharide (LPS). Experimental evidence indicated that impairment of LPS along with overexpression of pmrAB may have contributed to the development of polymyxin resistance in AC30. Cloning of a novel variant of the bla AmpC gene from AC29 and AC30, and its subsequent expression in E. coli also indicated its likely function as an extended-spectrum cephalosporinase.
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Affiliation(s)
- Soo-Sum Lean
- Faulty of Science, Institute of Biological Sciences, Universiti Malaya Kuala Lumpur, Malaysia
| | - Chew Chieng Yeo
- Faculty of Medicine, Biomedical Research Centre, Universiti Sultan Zainal Abidin Kuala Terengganu, Malaysia
| | - Zarizal Suhaili
- Faculty of Bioresources and Food Industry, Universiti Sultan Zainal Abidin Kuala Terengganu, Malaysia
| | - Kwai-Lin Thong
- Faulty of Science, Institute of Biological Sciences, Universiti Malaya Kuala Lumpur, Malaysia
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215
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216
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Huang XQ, Deng L, Lu G, He CH, Wu PQ, Xie ZW, Ashraf MA. Research on the treatment of Pseudomonas aeruginosa pneumonia in children by macrolide antibiotics. Open Med (Wars) 2015; 10:479-482. [PMID: 28352740 PMCID: PMC5368870 DOI: 10.1515/med-2015-0082] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Accepted: 11/09/2015] [Indexed: 11/15/2022] Open
Abstract
To observe a therapeutic effect of macrolide antibiotics in children with Pseudomonas aeruginosa pneumonia. Fifty-four cases of children with Pseudomonas aeruginosa pneumonia were randomly divided into an observation group (n=30) and a control group (n=24). The observation group was treated with macrolide antibiotics and cefoperazone/sulbactam. The control group was treated with cefoperazone/sulbactam during a course of 10-14 days. The total effective rate was 93.3% in the observation group, and 58.3% in the control group, and results in the observation group were superior to the control group notably (P>0.05). There were no significant differences in bacterial clearance rate, adverse reaction rate between two groups (P>0.05). The combined application of cefoperazone/sulbactam with macrolide antibiotics to treat Pseudomonas aeruginosa pneumonia in children would be a more effective clinical method.
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Affiliation(s)
- Xu-Qiang Huang
- Department of Respiration, Guangzhou Women and Children's Medical Center, Guangzhou, 510120, China
| | - Li Deng
- Department of Respiration, Guangzhou Women and Children's Medical Center, Guangzhou, 510120, China
| | - Gen Lu
- Department of Respiration, Guangzhou Women and Children's Medical Center, Guangzhou, 510120, China
| | - Chun-Hui He
- Department of Respiration, Guangzhou Women and Children's Medical Center, Guangzhou, 510120, China
| | - Pei-Qiong Wu
- Department of Respiration, Guangzhou Women and Children's Medical Center, Guangzhou, 510120, China
| | - Zhi-Wei Xie
- Department of Respiration, Guangzhou Women and Children's Medical Center, Guangzhou, 510120, China
| | - Muhammad Aqeel Ashraf
- Faculty of Science & Natural Resources, Universiti Malaysia Sabah 88400 Kota Kinabalu Sabah Malaysia
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217
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Esterly JS, Richardson CL, Eltoukhy NS, Qi C, Scheetz MH. Genetic Mechanisms of Antimicrobial Resistance of Acinetobacter baumannii. Ann Pharmacother 2015; 45:218-28. [PMID: 21304033 DOI: 10.1345/aph.1p084] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
OBJECTIVE To summarize published data identifying known genetic mechanisms of antibiotic resistance in Acinetobacter baumannii and the correlating phenotypic expression of antibiotic resistance. DATA SOURCES MEDLINE databases (1966-July 15, 2010) were searched to identify original reports of genetic mechanisms of antibiotic resistance in A. baumannii. DATA SYNTHESIS Numerous genetic mechanisms of resistance to multiple classes of antibiotics are known to exist in A. baumannii, a gram-negative bacterium increasingly implicated in nosocomial infections. Mechanisms may be constitutive or acquired via plasmids, integrons, and transposons. Methods of resistance include enzymatic modification of antibiotic molecules, modification of antibiotic target sites, expression of efflux pumps, and downregulation of cell membrane porin channel expression. Resistance to β-lactams appears to be primarily caused by β-lactamase production, including extended spectrum β-lactamases (b/aTEM, blaSHV, b/aTX-M,b/aKPC), metallo-β-lactamases (blaMP, blaVIM, bla, SIM), and most commonly, oxacillinases (blaOXA). Antibiotic target site alterations confer resistance to fluoroquinolones (gyrA, parC) and aminoglycosides (arm, rmt), and to a much lesser extent, β-lactams. Efflux pumps (tet, ade, abe) contribute to resistance against β-lactams, tetracyclines, fluoroquinolones, and aminoglycosides. Finally, porin channel deletion (carO, oprD) appears to contribute to β-lactam resistance and may contribute to rarely seen polymyxin resistance. Of note, efflux pumps and porin deletions as solitary mechanisms may not render clinical resistance to A. baumannii. CONCLUSIONS A. baumannii possesses copious genetic resistance mechanisms. Knowledge of local genotypes and expressed phenotypes for A. baumannii may aid clinicians more than phenotypic susceptibilities reported in large epidemiologic studies.
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Affiliation(s)
- John S Esterly
- John S Esterly PharmD BCPS, at time of writing, Infectious Diseases Pharmacotherapy Fellow, Department of Pharmacy Practice, College of Pharmacy, Midwestern University Chicago, Downers Grove, IL; now, Assistant Professor of Pharmacy Practice, College of Pharmacy, Chicago State University, Chicago, IL; Infectious Diseases Pharmacist, Northwestern Memorial Hospital, Chicago
| | - Chad L Richardson
- Chad L Richardson PharmD, at time of writing, Infectious Diseases Pharmacotherapy Resident, Department of Pharmacy Practice, College of Pharmacy, Midwestern University Chicago; now, Solid Organ Transplant Pharmacist, Northwestern Memorial Hospital
| | - Noha S Eltoukhy
- Noha S Eltoukhy PharmD BCPS, at time of writing, Infectious Diseases Pharmacy Resident, Department of Pharmacy Practice, College of Pharmacy, Midwestern University Chicago; Rush University Medical Center, Chicago; now, Infectious DIseases Clinical Pharmacy Specialist, St. Mary Medical Center, Langhorne, PA
| | - Chao Qi
- Chao Qi PhD, Assistant Professor of Pathology, Feinberg School of Medicine, Northwestern University; Assistant Director, Clinical Microbiology Laboratory, Northwestern Memorial Hospital, Chicago
| | - Marc H Scheetz
- Marc H Scheetz PharmD MSc BCPS, Assistant Professor of Pharmacy Practice, College of Pharmacy, Midwestern University Chicago; Infectious Diseases Pharmacist, Northwestern Memorial Hospital
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In vitroantimicrobial activity of S-649266, a catechol-substituted siderophore cephalosporin, when tested against non-fermenting Gram-negative bacteria. J Antimicrob Chemother 2015; 71:670-7. [DOI: 10.1093/jac/dkv402] [Citation(s) in RCA: 124] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Accepted: 10/29/2015] [Indexed: 11/14/2022] Open
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Kim A, Kutschke A, Ehmann DE, Patey SA, Crandon JL, Gorseth E, Miller AA, McLaughlin RE, Blinn CM, Chen A, Nayar AS, Dangel B, Tsai AS, Rooney MT, Murphy-Benenato KE, Eakin AE, Nicolau DP. Pharmacodynamic Profiling of a Siderophore-Conjugated Monocarbam in Pseudomonas aeruginosa: Assessing the Risk for Resistance and Attenuated Efficacy. Antimicrob Agents Chemother 2015; 59:7743-52. [PMID: 26438502 PMCID: PMC4649189 DOI: 10.1128/aac.00831-15] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Accepted: 09/29/2015] [Indexed: 01/05/2023] Open
Abstract
The objective of this study was to investigate the risk of attenuated efficacy due to adaptive resistance for the siderophore-conjugated monocarbam SMC-3176 in Pseudomonas aeruginosa by using a pharmacokinetic/pharmacodynamic (PK/PD) approach. MICs were determined in cation-adjusted Mueller-Hinton broth (MHB) and in Chelex-treated, dialyzed MHB (CDMHB). Spontaneous resistance was assessed at 2× to 16× the MIC and the resulting mutants sequenced. Efficacy was evaluated in a neutropenic mouse thigh model at 3.13 to 400 mg/kg of body weight every 3 h for 24 h and analyzed for association with free time above the MIC (fT>MIC). To closer emulate the conditions of the in vivo model, we developed a novel assay testing activity mouse whole blood (WB). All mutations were found in genes related to iron uptake: piuA, piuC, pirR, fecI, and pvdS. Against four P. aeruginosa isolates, SMC-3176 displayed predictable efficacy corresponding to the fT>MIC using the MIC in CDMHB (R(2) = 0.968 to 0.985), with stasis to 2-log kill achieved at 59.4 to 81.1%. Efficacy did not translate for P. aeruginosa isolate JJ 4-36, as the in vivo responses were inconsistent with fT>MIC exposures and implied a threshold concentration that was greater than the MIC. The results of the mouse WB assay indicated that efficacy was not predictable using the MIC for JJ 4-36 and four additional isolates, against which in vivo failures of another siderophore-conjugated β-lactam were previously reported. SMC-3176 carries a risk of attenuated efficacy in P. aeruginosa due to rapid adaptive resistance preventing entry via the siderophore-mediated iron uptake systems. Substantial in vivo testing is warranted for compounds using the siderophore approach to thoroughly screen for this in vitro-in vivo disconnect in P. aeruginosa.
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Affiliation(s)
- Aryun Kim
- Infection Innovative Medicines, AstraZeneca Pharmaceuticals LP, Waltham, Massachusetts, USA
| | - Amy Kutschke
- Infection Innovative Medicines, AstraZeneca Pharmaceuticals LP, Waltham, Massachusetts, USA
| | - David E Ehmann
- Infection Innovative Medicines, AstraZeneca Pharmaceuticals LP, Waltham, Massachusetts, USA
| | - Sara A Patey
- Infection Innovative Medicines, AstraZeneca Pharmaceuticals LP, Waltham, Massachusetts, USA
| | - Jared L Crandon
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, Connecticut, USA
| | - Elise Gorseth
- Infection Innovative Medicines, AstraZeneca Pharmaceuticals LP, Waltham, Massachusetts, USA
| | - Alita A Miller
- Infection Innovative Medicines, AstraZeneca Pharmaceuticals LP, Waltham, Massachusetts, USA
| | - Robert E McLaughlin
- Infection Innovative Medicines, AstraZeneca Pharmaceuticals LP, Waltham, Massachusetts, USA
| | - Christina M Blinn
- Infection Innovative Medicines, AstraZeneca Pharmaceuticals LP, Waltham, Massachusetts, USA
| | - April Chen
- Infection Innovative Medicines, AstraZeneca Pharmaceuticals LP, Waltham, Massachusetts, USA
| | - Asha S Nayar
- Infection Innovative Medicines, AstraZeneca Pharmaceuticals LP, Waltham, Massachusetts, USA
| | - Brian Dangel
- Infection Innovative Medicines, AstraZeneca Pharmaceuticals LP, Waltham, Massachusetts, USA
| | - Andy S Tsai
- Infection Innovative Medicines, AstraZeneca Pharmaceuticals LP, Waltham, Massachusetts, USA
| | - Michael T Rooney
- Infection Innovative Medicines, AstraZeneca Pharmaceuticals LP, Waltham, Massachusetts, USA
| | | | - Ann E Eakin
- Infection Innovative Medicines, AstraZeneca Pharmaceuticals LP, Waltham, Massachusetts, USA
| | - David P Nicolau
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, Connecticut, USA
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220
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Combination Antibiotic Therapy for the Definitive Management of Select Multidrug-Resistant Gram-Negative Rod Infections. CURRENT TREATMENT OPTIONS IN INFECTIOUS DISEASES 2015. [DOI: 10.1007/s40506-015-0066-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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221
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Odumosu BT, Adeniyi BA, Chandra R. First Detection of OXA-10 Extended-Spectrum Beta-Lactamases and the Occurrence of mexR and nfxB in Clinical Isolates of Pseudomonas aeruginosa from Nigeria. Chemotherapy 2015; 61:87-92. [PMID: 26606515 DOI: 10.1159/000441712] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Accepted: 10/15/2015] [Indexed: 11/19/2022]
Abstract
BACKGROUND The characterization of β-lactamase production in Pseudomonasaeruginosa is rarely reported in Nigeria. The objective of this study was to investigate the occurrence and characterize the different β-lactamases as well as mechanisms of fluoroquinolones resistance among P. aeruginosa isolated from various clinical sources from Nigeria. MATERIALS AND METHOD Isolates were investigated using PCR, RFLP and sequencing for the detection of various β-lactamases and efflux pump regulator genes. RESULT The prevalence of OXA-10, AmpC, CTX-M and SHV in P. aeruginosa was 80, 70, 5 and 5%, respectively. The coexistence of blaOXA-10 with blaAmpC, blaSHV and blaCTX-M was reported in 40, 5 and 5% of isolates, respectively. The efflux pump regulator genes mexR and nfxB were both amplified in 45% of the OXA-10-positive isolates. CONCLUSION This is the first report of the characterization of OXA-10 extended-spectrum β-lactamases and occurrence of mexR and nfxB efflux regulator genes in clinical isolates of P. aeruginosa in Nigeria.
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Acinetobacter baumannii Genes Required for Bacterial Survival during Bloodstream Infection. mSphere 2015; 1:mSphere00013-15. [PMID: 27303682 PMCID: PMC4863628 DOI: 10.1128/msphere.00013-15] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Accepted: 09/28/2015] [Indexed: 11/25/2022] Open
Abstract
A. baumannii is a significant cause of bacterial bloodstream infection in humans. Since multiple antibiotic resistance is becoming more common among strains of A. baumannii, there is an urgent need to develop novel tools to treat infections caused by this dangerous pathogen. To develop knowledge-guided treatment approaches for A. baumannii, a thorough understanding of the mechanism by which this pathogen causes bloodstream infection is required. Here, using a mouse model of infection, we report the identification of A. baumannii genes that are critical for the ability of this pathogen to cause bloodstream infections. This study lays the foundation for future research on A. baumannii genes that can be targeted to develop novel therapeutics against this emerging human pathogen. Acinetobacter baumannii is emerging as a leading global multiple-antibiotic-resistant nosocomial pathogen. The identity of genes essential for pathogenesis in a mammalian host remains largely unknown. Using transposon-directed insertion-site sequencing (TraDIS), we identified A. baumannii genes involved in bacterial survival in a leukopenic mouse model of bloodstream infection. Mice were inoculated with a pooled transposon mutant library derived from 109,000 mutants, and TraDIS was used to map transposon insertion sites in the genomes of bacteria in the inoculum and of bacteria recovered from mouse spleens. Unique transposon insertion sites were mapped and used to calculate a fitness factor for every insertion site based on its relative abundance in the inoculum and postinfection libraries. Eighty-nine transposon insertion mutants that were underrepresented after experimental infection in mice compared to their presence in the inocula were delineated as candidates for further evaluation. Genetically defined mutants lacking feoB (ferrous iron import), ddc (d-ala-d-ala-carboxypeptidase), and pntB (pyridine nucleotide transhydrogenase subunit) exhibited a fitness defect during systemic infection resulting from bacteremia. In vitro, these mutants, as well as a fepA (ferric enterobactin receptor) mutant, are defective in survival in human serum and within macrophages and are hypersensitive to killing by antimicrobial peptides compared to the survival of the parental strain under these conditions. Our data demonstrate that FepA is involved in the uptake of exogenous enterobactin in A. baumannii. Genetic complementation rescues the phenotypes of mutants in assays that emulate conditions encountered during infection. In summary, we have determined novel A. baumannii fitness genes involved in the pathogenesis of mammalian infection. IMPORTANCEA. baumannii is a significant cause of bacterial bloodstream infection in humans. Since multiple antibiotic resistance is becoming more common among strains of A. baumannii, there is an urgent need to develop novel tools to treat infections caused by this dangerous pathogen. To develop knowledge-guided treatment approaches for A. baumannii, a thorough understanding of the mechanism by which this pathogen causes bloodstream infection is required. Here, using a mouse model of infection, we report the identification of A. baumannii genes that are critical for the ability of this pathogen to cause bloodstream infections. This study lays the foundation for future research on A. baumannii genes that can be targeted to develop novel therapeutics against this emerging human pathogen.
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Boyle DP, Zembower TR. Epidemiology and Management of Emerging Drug-Resistant Gram-Negative Bacteria. Urol Clin North Am 2015; 42:493-505. [DOI: 10.1016/j.ucl.2015.05.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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Lai JH, Yang JT, Chern J, Chen TL, Wu WL, Liao JH, Tsai SF, Liang SY, Chou CC, Wu SH. Comparative Phosphoproteomics Reveals the Role of AmpC β-lactamase Phosphorylation in the Clinical Imipenem-resistant Strain Acinetobacter baumannii SK17. Mol Cell Proteomics 2015; 15:12-25. [PMID: 26499836 DOI: 10.1074/mcp.m115.051052] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Indexed: 01/13/2023] Open
Abstract
Nosocomial infectious outbreaks caused by multidrug-resistant Acinetobacter baumannii have emerged as a serious threat to human health. Phosphoproteomics of pathogenic bacteria has been used to identify the mechanisms of bacterial virulence and antimicrobial resistance. In this study, we used a shotgun strategy combined with high-accuracy mass spectrometry to analyze the phosphoproteomics of the imipenem-susceptible strain SK17-S and -resistant strain SK17-R. We identified 410 phosphosites on 248 unique phosphoproteins in SK17-S and 285 phosphosites on 211 unique phosphoproteins in SK17-R. The distributions of the Ser/Thr/Tyr/Asp/His phosphosites in SK17-S and SK17-R were 47.0%/27.6%/12.4%/8.0%/4.9% versus 41.4%/29.5%/17.5%/6.7%/4.9%, respectively. The Ser-90 phosphosite, located on the catalytic motif S(88)VS(90)K of the AmpC β-lactamase, was first identified in SK17-S. Based on site-directed mutagenesis, the nonphosphorylatable mutant S90A was found to be more resistant to imipenem, whereas the phosphorylation-simulated mutant S90D was sensitive to imipenem. Additionally, the S90A mutant protein exhibited higher β-lactamase activity and conferred greater bacterial protection against imipenem in SK17-S compared with the wild-type. In sum, our results revealed that in A. baumannii, Ser-90 phosphorylation of AmpC negatively regulates both β-lactamase activity and the ability to counteract the antibiotic effects of imipenem. These findings highlight the impact of phosphorylation-mediated regulation in antibiotic-resistant bacteria on future drug design and new therapies.
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Affiliation(s)
- Juo-Hsin Lai
- From the ‡Institute of Biochemical Sciences, College of Life Sciences, National Taiwan University, Taipei 10617, Taiwan; §Institute of Biological Chemistry, Academia Sinica. Taipei 11529, Taiwan
| | - Jhih-Tian Yang
- §Institute of Biological Chemistry, Academia Sinica. Taipei 11529, Taiwan; ¶Ph.D. Program in Microbial Genomics, National Chung Hsing University and Academia Sinica, Taiwan
| | - Jeffy Chern
- §Institute of Biological Chemistry, Academia Sinica. Taipei 11529, Taiwan; ‖Chemical Biology and Molecular Biophysics Program, Taiwan International Graduate Program, Academia Sinica, Taipei 11529, Taiwan; **Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan
| | - Te-Li Chen
- ‡‡Institute of Clinical Medicine, School of Medicine, National Yang Ming University, Taipei 11221, Taiwan; §§Division of Infectious Diseases, Department of Medicine, Taipei Veterans General Hospital, Taipei 11217, Taiwan; ¶¶Department of Medicine, Cheng Hsin General Hospital, Taipei 11220, Taiwan
| | - Wan-Ling Wu
- §Institute of Biological Chemistry, Academia Sinica. Taipei 11529, Taiwan
| | - Jiahn-Haur Liao
- §Institute of Biological Chemistry, Academia Sinica. Taipei 11529, Taiwan
| | - Shih-Feng Tsai
- ‖‖Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taipei 11221, Taiwan; Institute of Molecular and Genomic Medicine, National Health Research Institutes, Miaoli 35053, Taiwan
| | - Suh-Yuen Liang
- §Institute of Biological Chemistry, Academia Sinica. Taipei 11529, Taiwan; Core Facilities for Protein Structural Analysis, Institute of Biological Chemistry, Academia Sinica, Taipei 11529, Taiwan
| | - Chi-Chi Chou
- §Institute of Biological Chemistry, Academia Sinica. Taipei 11529, Taiwan; Core Facilities for Protein Structural Analysis, Institute of Biological Chemistry, Academia Sinica, Taipei 11529, Taiwan
| | - Shih-Hsiung Wu
- From the ‡Institute of Biochemical Sciences, College of Life Sciences, National Taiwan University, Taipei 10617, Taiwan; §Institute of Biological Chemistry, Academia Sinica. Taipei 11529, Taiwan; ‖Chemical Biology and Molecular Biophysics Program, Taiwan International Graduate Program, Academia Sinica, Taipei 11529, Taiwan; **Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan;
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225
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How Porin Heterogeneity and Trade-Offs Affect the Antibiotic Susceptibility of Gram-Negative Bacteria. Genes (Basel) 2015; 6:1113-24. [PMID: 26506392 PMCID: PMC4690030 DOI: 10.3390/genes6041113] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Revised: 09/04/2015] [Accepted: 10/08/2015] [Indexed: 11/17/2022] Open
Abstract
Variations in porin proteins are common in Gram-negative pathogens. Altered or absent porins reduce access of polar antibiotics across the outer membrane and can thus contribute to antibiotic resistance. Reduced permeability has a cost however, in lowering access to nutrients. This trade-off between permeability and nutritional competence is the source of considerable natural variation in porin gate-keeping. Mutational changes in this trade-off are frequently selected, so susceptibility to detergents and antibiotics is polymorphic in environmental isolates as well as pathogens. Understanding the mechanism, costs and heterogeneity of antibiotic exclusion by porins will be crucial in combating Gram negative infections.
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226
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Impact of a Cross-Kingdom Signaling Molecule of Candida albicans on Acinetobacter baumannii Physiology. Antimicrob Agents Chemother 2015; 60:161-7. [PMID: 26482299 DOI: 10.1128/aac.01540-15] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Accepted: 10/03/2015] [Indexed: 01/14/2023] Open
Abstract
Multidrug-resistant (MDR) Acinetobacter baumannii is an opportunistic human pathogen that has become highly problematic in the clinical environment. Novel therapies are desperately required. To assist in identifying new therapeutic targets, the antagonistic interactions between A. baumannii and the most common human fungal pathogen, Candida albicans, were studied. We have observed that the C. albicans quorum-sensing molecule, farnesol, has cross-kingdom interactions, affecting the viability of A. baumannii. To gain an understanding of its mechanism, the transcriptional profile of A. baumannii exposed to farnesol was examined. Farnesol caused dysregulation of a large number of genes involved in cell membrane biogenesis, multidrug efflux pumps (AcrAB-like and AdeIJK-like), and A. baumannii virulence traits such as biofilm formation (csuA, csuB, and ompA) and motility (pilZ and pilH). We also observed a strong induction in genes involved in cell division (minD, minE, ftsK, ftsB, and ftsL). These transcriptional data were supported by functional assays showing that farnesol disrupts A. baumannii cell membrane integrity, alters cell morphology, and impairs virulence characteristics such as biofilm formation and twitching motility. Moreover, we showed that A. baumannii uses efflux pumps as a defense mechanism against this eukaryotic signaling molecule. Owing to its effects on membrane integrity, farnesol was tested to see if it potentiated the activity of the membrane-acting polymyxin antibiotic colistin. When coadministered, farnesol increased sensitivity to colistin for otherwise resistant strains. These data provide mechanistic understanding of the antagonistic interactions between diverse pathogens and may provide important insights into novel therapeutic strategies.
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227
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Évaluation du pouvoir antimicrobien des huiles essentielles de sept plantes médicinales récoltées au Maroc. ACTA ACUST UNITED AC 2015. [DOI: 10.1007/s10298-015-0996-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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228
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Microbicides Alter the Expression and Function of RND-Type Efflux Pump AdeABC in Biofilm-Associated Cells of Acinetobacter baumannii Clinical Isolates. Antimicrob Agents Chemother 2015; 60:57-63. [PMID: 26459900 DOI: 10.1128/aac.01045-15] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2015] [Accepted: 10/03/2015] [Indexed: 11/20/2022] Open
Abstract
Acinetobacter baumannii is a Gram-negative bacterium that causes nosocomial infections worldwide. This microbe's propensity to form biofilms allows it to persist and to survive on clinical abiotic surfaces for long periods. In fact, A. baumannii biofilm formation and its multidrug-resistant nature severely compromise our capacity to care for patients in hospital environments. In contrast, microbicides such as cetrimide (CT) and chlorhexidine (CHX) play important roles in the prevention and treatment of infections. We assessed the efficacy of CT and CHX, either alone or in combination, in eradicating A. baumannii biofilms formed by clinical isolates, by using stainless steel washers to mimic hard abiotic surfaces found in hospital settings. We demonstrated that increasing amounts of each microbicide, alone or in combination, were able to damage and to reduce the viability of A. baumannii biofilms efficaciously. Interestingly, the adeB gene of the resistance-nodulation-cell division (RND) family is predominantly associated with acquired resistance to antimicrobials in A. baumannii. We showed that CT and CHX adversely modified the expression and function of the RND-type efflux pump AdeABC in biofilm-associated A. baumannii cells. Furthermore, we established that these microbicides decreased the negative charges on A. baumannii cell membranes, causing dysregulation of the efflux pump and leading to cell death. Our findings suggest that CT and CHX, alone or in combination, can be used efficaciously for eradication of A. baumannii from hospital surfaces, in order to reduce infections caused by this nosocomial agent.
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Escherichia coli Overexpressing a Baeyer-Villiger Monooxygenase from Acinetobacter radioresistens Becomes Resistant to Imipenem. Antimicrob Agents Chemother 2015; 60:64-74. [PMID: 26459905 DOI: 10.1128/aac.01088-15] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Accepted: 10/03/2015] [Indexed: 11/20/2022] Open
Abstract
Antimicrobial resistance is a global issue currently resulting in the deaths of hundreds of thousands of people a year worldwide. Data present in the literature illustrate the emergence of many bacterial species that display resistance to known antibiotics; Acinetobacter spp. are a good example of this. We report here that Acinetobacter radioresistens has a Baeyer-Villiger monooxygenase (Ar-BVMO) with 100% amino acid sequence identity to the ethionamide monooxygenase of multidrug-resistant (MDR) Acinetobacter baumannii. Both enzymes are only distantly phylogenetically related to other canonical bacterial BVMO proteins. Ar-BVMO not only is capable of oxidizing two anticancer drugs metabolized by human FMO3, danusertib and tozasertib, but also can oxidize other synthetic drugs, such as imipenem. The latter is a member of the carbapenems, a clinically important antibiotic family used in the treatment of MDR bacterial infections. Susceptibility tests performed by the Kirby-Bauer disk diffusion method demonstrate that imipenem-sensitive Escherichia coli BL21 cells overexpressing Ar-BVMO become resistant to this antibiotic. An agar disk diffusion assay proved that when imipenem reacts with Ar-BVMO, it loses its antibiotic property. Moreover, an NADPH consumption assay with the purified Ar-BVMO demonstrates that this antibiotic is indeed a substrate, and its product is identified by liquid chromatography-mass spectrometry to be a Baeyer-Villiger (BV) oxidation product of the carbonyl moiety of the β-lactam ring. This is the first report of an antibiotic-inactivating BVMO enzyme that, while mediating its usual BV oxidation, also operates by an unprecedented mechanism of carbapenem resistance.
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230
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Multiple Genetic Mutations Associated with Polymyxin Resistance in Acinetobacter baumannii. Antimicrob Agents Chemother 2015; 59:7899-902. [PMID: 26438500 DOI: 10.1128/aac.01884-15] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Accepted: 09/30/2015] [Indexed: 11/20/2022] Open
Abstract
We studied polymyxin B resistance in 10 pairs of clinical Acinetobacter baumannii isolates, two of which had developed polymyxin B resistance in vivo. All polymyxin B-resistant isolates had lower growth rates than and substitution mutations in the lpx or pmrB gene compared to their parent isolates. There were significant differences in terms of antibiotic susceptibility and genetic determinants of resistance in A. baumannii isolates that had developed polymyxin B resistance in vivo compared to isolates that had developed polymyxin B resistance in vitro.
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231
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Smith EW, Zhang X, Behzadi C, Andrews LD, Cohen F, Chen Y. Structures of Pseudomonas aeruginosa LpxA Reveal the Basis for Its Substrate Selectivity. Biochemistry 2015; 54:5937-48. [PMID: 26352800 DOI: 10.1021/acs.biochem.5b00720] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In Gram-negative bacteria, the first step of lipid A biosynthesis is catalyzed by UDP-N-acetylglucosamine acyltransferase (LpxA) through the transfer of a R-3-hydroxyacyl chain from the acyl carrier protein (ACP) to the 3-hydroxyl group of UDP-GlcNAc. Previous studies suggest that LpxA is a critical determinant of the acyl chain length found in lipid A, which varies among species of bacteria. In Escherichia coli and Leptospira interrogans, LpxA prefers to incorporate longer R-3-hydroxyacyl chains (C14 and C12, respectively), whereas in Pseudomonas aeruginosa, the enzyme is selective for R-3-hydroxydecanoyl, a 10-hydrocarbon long acyl chain. We now report three P. aeruginosa LpxA crystal structures: apo protein, substrate complex with UDP-GlcNAc, and product complex with UDP-3-O-(R-3-hydroxydecanoyl)-GlcNAc. A comparison between the apo form and complexes identifies key residues that position UDP-GlcNAc appropriately for catalysis and supports the role of catalytic His121 in activating the UDP-GlcNAc 3-hydroxyl group for nucleophilic attack during the reaction. The product-complex structure, for the first time, offers structural insights into how Met169 serves to constrain the length of the acyl chain and thus functions as the so-called hydrocarbon ruler. Furthermore, compared with ortholog LpxA structures, the purported oxyanion hole, formed by the backbone amide group of Gly139, displays a different conformation in P. aeruginosa LpxA, which suggests flexibility of this structural feature important for catalysis and the potential need for substrate-induced conformational change in catalysis. Taken together, the three structures provide valuable insights into P. aeruginosa LpxA catalysis and substrate specificity as well as templates for future inhibitor discovery.
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Affiliation(s)
- Emmanuel W Smith
- Department of Molecular Medicine, University of South Florida , 12901 Bruce B. Downs Boulevard, Tampa, Florida 33612, United States
| | - XiuJun Zhang
- Department of Molecular Medicine, University of South Florida , 12901 Bruce B. Downs Boulevard, Tampa, Florida 33612, United States
| | - Cyrus Behzadi
- Department of Molecular Medicine, University of South Florida , 12901 Bruce B. Downs Boulevard, Tampa, Florida 33612, United States
| | - Logan D Andrews
- ACHAOGEN Inc. , 7000 Shoreline Court, South San Francisco, California 94080, United States
| | - Frederick Cohen
- ACHAOGEN Inc. , 7000 Shoreline Court, South San Francisco, California 94080, United States
| | - Yu Chen
- Department of Molecular Medicine, University of South Florida , 12901 Bruce B. Downs Boulevard, Tampa, Florida 33612, United States
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Adesoji AT, Ogunjobi AA, Olatoye IO. Molecular characterization of selected multidrug resistant Pseudomonas from water distribution systems in southwestern Nigeria. Ann Clin Microbiol Antimicrob 2015; 14:39. [PMID: 26328550 PMCID: PMC4557310 DOI: 10.1186/s12941-015-0102-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Accepted: 08/19/2015] [Indexed: 12/26/2022] Open
Abstract
Background Persistence of antibiotic resistant bacteria, including multidrug resistant (MDR) pseudomonads, is an important environmental health problem associated with drinking water distribution systems (DWDS) worldwide. There is paucity of data on the molecular characteristics of antibiotic resistance genes and their mode of transfer among pseudomonads from DWDS located in resource-challenged areas such as southwestern Nigeria. Methods MDR pseudomonads (n = 22) were selected from a panel of 296 different strains that were isolated from treated and untreated water in six DWDS located across southwest Nigeria. Primarily, the isolated pseudomonads strains were identified by 16S rDNA sequencing and antibiotic-resistance testing was completed using agar breakpoints assays. The final panel of strains of resistant to more than three classes of antibiotics (i.e. MDR), were further characterized by PCR genotyping, Sanger sequencing, and plasmid profiling. Results Pseudomonad resistance to gentamicin and streptomycin ranged from 22.7 to 54.6 % while resistance to tetracycline, ceftiofur and sulphamethoxazole ranged from 40.9 to 77.3 %. The most commonly detected antibiotic resistance genes were tet(A) (31.8 % of isolates), sul1 (31.8 %), blaTEM (40.9 %) and aph(3″)c (36.4 %). Class 1 integron sequences were evident in 27.3 % of isolates and they harbored genes encoding resistance to aminoglycosides (aadA2, aadA1), trimethoprim (dfrA15, dfr7) and sulphonamide (sul1) while the plasmid ranged between 22 and 130 kb. Conclusions Pseudomonas spp, isolated from these DWDS possess resistance genes and factors that are of public and environmental health significance. Therefore, has the potential of contributing to the global scourge of resistance genes transfer in human, animals and environments, thereby, useful in the epidemiology of antimicrobial resistance.
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Affiliation(s)
- Ayodele T Adesoji
- Department of Biological Sciences, Federal University Dutsin-Ma, Dutsin-Ma, Katsina State, Nigeria.
| | | | - Isaac O Olatoye
- Department of Veterinary Public Health and Preventive Medicine, University of Ibadan, Ibadan, Oyo State, Nigeria. .,Paul G. Allen School for Global Animal Health, Washington State University, Pullman, WA, USA.
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Russotto V, Cortegiani A, Graziano G, Saporito L, Raineri SM, Mammina C, Giarratano A. Bloodstream infections in intensive care unit patients: distribution and antibiotic resistance of bacteria. Infect Drug Resist 2015; 8:287-96. [PMID: 26300651 PMCID: PMC4536838 DOI: 10.2147/idr.s48810] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Bloodstream infections (BSIs) are among the leading infections in critically ill patients. The case-fatality rate associated with BSIs in patients admitted to intensive care units (ICUs) reaches 35%–50%. The emergence and diffusion of bacteria with resistance to antibiotics is a global health problem. Multidrug-resistant bacteria were detected in 50.7% of patients with BSIs in a recently published international observational study, with methicillin resistance detected in 48% of Staphylococcus aureus strains, carbapenem resistance detected in 69% of Acinetobacter spp., in 38% of Klebsiella pneumoniae, and in 37% of Pseudomonas spp. Prior hospitalization and antibiotic exposure have been identified as risk factors for infections caused by resistant bacteria in different studies. Patients with BSIs caused by resistant strains showed an increased risk of mortality, which may be explained by a higher incidence of inappropriate empirical therapy in different studies. The molecular genetic characterization of resistant bacteria allows the understanding of the most common mechanisms underlying their resistance and the adoption of surveillance measures. Knowledge of epidemiology, risk factors, mechanisms of resistance, and outcomes of BSIs caused by resistant bacteria may have a major influence on global management of ICU patients. The aim of this review is to provide the clinician an update on BSIs caused by resistant bacteria in ICU patients.
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Affiliation(s)
- Vincenzo Russotto
- Department of Biopathology and Medical Biotechnologies (DIBIMED), Section of Anaesthesia, Analgesia, Intensive Care and Emergency, Paolo Giaccone University Hospital, University of Palermo, Palermo, Italy
| | - Andrea Cortegiani
- Department of Biopathology and Medical Biotechnologies (DIBIMED), Section of Anaesthesia, Analgesia, Intensive Care and Emergency, Paolo Giaccone University Hospital, University of Palermo, Palermo, Italy
| | - Giorgio Graziano
- Department of Sciences for Health Promotion and Mother-Child Care, University of Palermo, Palermo, Italy
| | - Laura Saporito
- Department of Sciences for Health Promotion and Mother-Child Care, University of Palermo, Palermo, Italy
| | - Santi Maurizio Raineri
- Department of Biopathology and Medical Biotechnologies (DIBIMED), Section of Anaesthesia, Analgesia, Intensive Care and Emergency, Paolo Giaccone University Hospital, University of Palermo, Palermo, Italy
| | - Caterina Mammina
- Department of Sciences for Health Promotion and Mother-Child Care, University of Palermo, Palermo, Italy
| | - Antonino Giarratano
- Department of Biopathology and Medical Biotechnologies (DIBIMED), Section of Anaesthesia, Analgesia, Intensive Care and Emergency, Paolo Giaccone University Hospital, University of Palermo, Palermo, Italy
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234
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Maisch T. Resistance in antimicrobial photodynamic inactivation of bacteria. Photochem Photobiol Sci 2015; 14:1518-26. [PMID: 26098395 DOI: 10.1039/c5pp00037h] [Citation(s) in RCA: 169] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Antibiotics have increasingly lost their impact to kill bacteria efficiently during the last 10 years. The emergence and dissemination of superbugs with resistance to multiple antibiotic classes have occurred among Gram-positive and Gram-negative strains including Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacter strains. These six superbugs can "escape" more or less any single kind of antibiotic treatment. That means bacteria are very good at developing resistance against antibiotics in a short time. One new approach is called photodynamic antimicrobial chemotherapy (PACT) which already has demonstrated an efficient antimicrobial efficacy among multi-resistant bacteria. Until now it has been questionable if bacteria can develop resistance against PACT. This perspective summarises the current knowledge about the susceptibility of bacteria towards oxidative stress and sheds some light on possible strategies of the development of photodynamic inactivation of bacteria (PACT)-induced oxidative stress resistance by bacteria.
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Affiliation(s)
- Tim Maisch
- Department of Dermatology, Antimicrobial Photodynamic and Cold Plasma Research Unit, University Hospital Regensburg, Regensburg, Germany.
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235
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Mijovic G, Pejakov L, Vujosevic D. Antibiotic susceptibility of Acinetobacter species in intensive care unit in Montenegro. J Chemother 2015; 28:273-6. [PMID: 25979577 DOI: 10.1179/1973947815y.0000000037] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
The global increase in multidrug resistance of Acinetobacter has created widespread problems in the treatment of patients in intensive care units (ICUs). The aim of this study was to assess the current level of antimicrobial susceptibility of Acinetobacter species in ICU of Clinical Centre of Montenegro and determine their epidemiology. Antibiotic susceptibility was tested in 70 isolates of Acinetobacter collected from non-repeating samples taken from 40 patients. The first nine isolates were genotyped by repetitive sequence-based PCR (rep-PCR). Tigecycline was found to be the most active antimicrobial agent with 80.6% of susceptibility. All the isolates were multidrug resistant with fully resistance to cefalosporinas, piperacillin and piperacillin/tazobactam. More than half of them (58.5%) were probably extensively resistant. Seven out of nine examined strains were clonally related by rep-PCR. Our results showed extremely high rate of multidrug resistance (MDR) of Acinetobacter isolates and high percentage of its clonally spreading.
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236
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Potron A, Poirel L, Nordmann P. Emerging broad-spectrum resistance in Pseudomonas aeruginosa and Acinetobacter baumannii: Mechanisms and epidemiology. Int J Antimicrob Agents 2015; 45:568-85. [PMID: 25857949 DOI: 10.1016/j.ijantimicag.2015.03.001] [Citation(s) in RCA: 451] [Impact Index Per Article: 50.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Accepted: 03/05/2015] [Indexed: 02/07/2023]
Abstract
Multidrug resistance is quite common among non-fermenting Gram-negative rods, in particular among clinically relevant species including Pseudomonas aeruginosa and Acinetobacter baumannii. These bacterial species, which are mainly nosocomial pathogens, possess a diversity of resistance mechanisms that may lead to multidrug or even pandrug resistance. Extended-spectrum β-lactamases (ESBLs) conferring resistance to broad-spectrum cephalosporins, carbapenemases conferring resistance to carbapenems, and 16S rRNA methylases conferring resistance to all clinically relevant aminoglycosides are the most important causes of concern. Concomitant resistance to fluoroquinolones, polymyxins (colistin) and tigecycline may lead to pandrug resistance. The most important mechanisms of resistance in P. aeruginosa and A. baumannii and their most recent dissemination worldwide are detailed here.
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Affiliation(s)
- Anaïs Potron
- Laboratoire de Bactériologie, Faculté de Médecine-Pharmacie, Centre Hospitalier Régional Universitaire, Université de Franche-Comté, Besançon, France
| | - Laurent Poirel
- Emerging Antibiotic Resistance Medical and Molecular Microbiology Unit, Department of Medicine, Faculty of Science, University of Fribourg, Fribourg, Switzerland.
| | - Patrice Nordmann
- Emerging Antibiotic Resistance Medical and Molecular Microbiology Unit, Department of Medicine, Faculty of Science, University of Fribourg, Fribourg, Switzerland; HFR - Hôpital Cantonal de Fribourg, Fribourg, Switzerland
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237
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Oh MH, Lee J, Choi SK, Son SY. Analysis of class I integrons responsible for antibiotics resistance in Pseudomonas aeruginosa. Genes Genomics 2015. [DOI: 10.1007/s13258-014-0242-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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238
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Kazi M, Nikam C, Shetty A, Rodrigues C. Dual-tubed multiplex-PCR for molecular characterization of carbapenemases isolated among Acinetobacter spp. and Pseudomonas spp. J Appl Microbiol 2015; 118:1096-102. [PMID: 25647446 DOI: 10.1111/jam.12770] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Revised: 01/21/2015] [Accepted: 01/28/2015] [Indexed: 11/30/2022]
Abstract
AIM To molecularly characterize clinical isolates of Acinetobacter spp. and Pseudomonas spp. from various clinical samples so as to identify the carbapenemases mechanisms harboured by them. MATERIALS AND RESULTS A total of 95 carbapenem-resistant, nonduplicate, multi-drug resistant Gram-negative clinical isolates (53 Acinetobacter spp. and 42 Pseudomonas spp.), were collected between July and December 2012. Modified Hodge test (MHT) for the detection of carbapenemases was performed. Inhibitor-based test, EDTA for the detection of metallo-β-lactamases (MBL) and phenyl boronic acid (PBA) for the detection of Klebsiella pneumoniae carbapenemase (KPC), were performed to distinguish between different classes of β-lactamases. Two-tubed multiplex-PCR was performed for genotypic characterization of different classes of carbapenemases ((blaNDM-1 , blaOXA-48 like , blaKPC , blaVIM , blaIMP ), (blaOXA-23 like , blaOXA-24 like , blaOXA-51 like , blaOXA-58 like )). Eighty-five per cent (81/95) isolates were carbapenemase producers. Among these, 56.7% (44) were multiple carbapenemase producers. Furthermore, 48.14% (39) were MBLs, 35.8% (29) were carbapenem hydrolyzing class D β-lactamases (CHDLs), 16% (13) had MBLs as well as CHDLs and 14.7% (14/95) had none of the targeted resistance mechanisms. The overall rate of concordance between phenotypic and genotypic test was 97% and 98% for the detection of carbapenemases and MBL, respectively. CONCLUSION This is the first study from Western India which highlights the presence of multiple carbapenemases in nonfermenters Gram-negative bacilli (NFGNB). Co-existence of multiple carbapenemases along with other resistance mechanisms might result in treatment failure. Molecular characterization of the resistance mechanisms of suspected pathogens would help provide appropriate antimicrobial treatment for good clinical outcome. SIGNIFICANCE AND IMPACT OF THE STUDY Dual-tubed multiplex PCR decreases the time of amplification and thus the turnaround time which is crucial in clinical microbiology; this would be helpful in rapid characterization of CHDLs and MBLs.
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Affiliation(s)
- M Kazi
- Department of Microbiology, P. D. Hinduja National Hospital and Medical Research Centre, Mahim, Mumbai, India
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239
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Weintrob AC, Roediger MP, Barber M, Summers A, Fieberg AM, Dunn J, Seldon V, Leach F, Huang XZ, Nikolich MP, Wortmann GW. Natural History of Colonization with Gram-Negative Multidrug-Resistant Organisms among Hospitalized Patients. Infect Control Hosp Epidemiol 2015; 31:330-7. [DOI: 10.1086/651304] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Objective.To determine the anatomic sites and natural history of colonization with gram-negative multidrug-resistant organisms (MDROs).Design.Prospective, longitudinal cohort study.Setting.Walter Reed Army Medical Center, a 236-bed tertiary care center in Washington, DC.Patients.Deployed subjects (ie, inpatients medically evacuated from Iraq or Afghanistan) or nondeployed subjects admitted to the same hospital.Methods.Consenting patients had 6 anatomic sites cultured every 3 days for 2 weeks and then weekly. Gram-negative organisms resistant to 3 or more classes of antibiotics were considered MDROs. Isolates were genotyped using pulsed-field gel electrophoresis. Clinical data, data on antibiotic use, and clinical culture results were collected.Results.Of 60 deployed subjects, 14 (23%) were colonized with an MDRO at admission, and 13 (22%) had incident colonization during hospitalization. The groin was the most sensitive anatomic site for detecting MDRO colonization, and all but one subject remained colonized for the duration of their hospitalization. Sixty percent of subjects with incident Acinetobacter colonization and 25% of subjects with incident Klebsiella colonization had strains that were related to those isolated from other subjects. Of 60 nondeployed subjects, 5 (8%) were colonized with an MDRO at admission; all had recent healthcare contact, and 1 nondeployed subject had an isolate related to a strain recovered from a deployed subject.Conclusions.Colonization with gram-negative MDROs is common among patients with war-related trauma admitted to a military hospital and also occurs among nondeployed patients with recent healthcare contact. The groin is the most sensitive anatomic site for active surveillance, and spontaneous decolonization is rare.
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240
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Dahiru M, Enabulele OI. <i>Acinetobacter baumannii</i> in Birds’ Feces: A Public Health Threat to Vegetables and Irrigation Farmers. ACTA ACUST UNITED AC 2015. [DOI: 10.4236/aim.2015.510072] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Vandecandelaere I, Coenye T. Microbial composition and antibiotic resistance of biofilms recovered from endotracheal tubes of mechanically ventilated patients. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2015; 830:137-55. [PMID: 25366226 DOI: 10.1007/978-3-319-11038-7_9] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
In critically ill patients, breathing is impaired and mechanical ventilation, using an endotracheal tube (ET) connected to a ventilator, is necessary. Although mechanical ventilation is a life-saving procedure, it is not without risk. Because of several reasons, a biofilm often forms at the distal end of the ET and this biofilm is a persistent source of bacteria which can infect the lungs, causing ventilator-associated pneumonia (VAP). There is a link between the microbial flora of ET biofilms and the microorganisms involved in the onset of VAP. Culture dependent and independent techniques were already used to identify the microbial flora of ET biofilms and also, the antibiotic resistance of microorganisms obtained from ET biofilms was determined. The ESKAPE pathogens play a dominant role in the onset of VAP and these organisms were frequently identified in ET biofilms. Also, antibiotic resistant microorganisms were frequently present in ET biofilms. Members of the normal oral flora were also identified in ET biofilms but it is thought that these organisms initiate ET biofilm formation and are not directly involved in the development of VAP.
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Affiliation(s)
- Ilse Vandecandelaere
- Laboratory of Pharmaceutical Microbiology, Ghent University, Ottergemsesteenweg 460, 9000, Ghent, Belgium
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242
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Vogwill T, MacLean RC. The genetic basis of the fitness costs of antimicrobial resistance: a meta-analysis approach. Evol Appl 2014; 8:284-95. [PMID: 25861386 PMCID: PMC4380922 DOI: 10.1111/eva.12202] [Citation(s) in RCA: 232] [Impact Index Per Article: 23.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Accepted: 08/07/2014] [Indexed: 12/12/2022] Open
Abstract
The evolution of antibiotic resistance carries a fitness cost, expressed in terms of reduced competitive ability in the absence of antibiotics. This cost plays a key role in the dynamics of resistance by generating selection against resistance when bacteria encounter an antibiotic-free environment. Previous work has shown that the cost of resistance is highly variable, but the underlying causes remain poorly understood. Here, we use a meta-analysis of the published resistance literature to determine how the genetic basis of resistance influences its cost. We find that on average chromosomal resistance mutations carry a larger cost than acquiring resistance via a plasmid. This may explain why resistance often evolves by plasmid acquisition. Second, we find that the cost of plasmid acquisition increases with the breadth of its resistance range. This suggests a potentially important limit on the evolution of extensive multidrug resistance via plasmids. We also find that epistasis can significantly alter the cost of mutational resistance. Overall, our study shows that the cost of antimicrobial resistance can be partially explained by its genetic basis. It also highlights both the danger associated with plasmidborne resistance and the need to understand why resistance plasmids carry a relatively low cost.
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Affiliation(s)
- Tom Vogwill
- Department of Zoology, University of Oxford Oxford, UK
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243
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Bokaeian M, Shahraki Zahedani S, Soltanian Bajgiran M, Ansari Moghaddam A. Frequency of PER, VEB, SHV, TEM and CTX-M Genes in Resistant Strains of Pseudomonas aeruginosa Producing Extended Spectrum β-Lactamases. Jundishapur J Microbiol 2014; 8:e13783. [PMID: 25789123 PMCID: PMC4350043 DOI: 10.5812/jjm.13783] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Revised: 01/18/2014] [Accepted: 01/21/2014] [Indexed: 11/16/2022] Open
Abstract
Background: Pseudomonas aeruginosa is the most common pathogen causing nosocomial infections. Resistance of P. aeruginosa strains to broad-spectrum cephalosporins may be mediated by extended-spectrum β-lactamases (ESBLs). Objectives: We intended to investigate the prevalence of ESBLs and antimicrobial susceptibilities of P. aeruginosa isolated from patients in Zahedan, Iran. Materials and Methods: In this cross-sectional study, during 2012–2013, 116 P. aeruginosa isolates were collected from a teaching hospital in Zahedan, Iran. Susceptibility to eight antimicrobial agents was carried out by disk diffusion method. The ESBL producing strains were detected by combination disk test (CDT). ESBL positive isolates as well as other isolates showing minimum inhibitory concentrations (MICs) ≥ 4 μg/mL for ceftazidime, cefotaxime, ceftriaxone and aztreonam, were screened for the presence of the genes encoding blaTEM, blaSHV, blaPER-1 and blaVEB-1, by polymerase chain reaction (PCR). Results: Ciprofloxacin and piperacillin were the most efficient antipseudomonal agents. The results disclosed that 19 (16.37%) of the isolates were multidrug resistant and 8 (6.89%) were ESBL-positive. Of the 116 isolates, 30 (25.86%) were resistant to at least one of the antibiotics ceftazidime, ceftriaxone, cefotaxime or aztreonam and among these 30 (100%), 4 (13.3%), 2 (6.6%) and 2 (6.6%), amplified blaTEM, blaVEB-1, blaPER-1 and blaSHV, respectively. From the 30 TEM-positive isolates, 22 were ESBL-negative. Sequencing of the ESBL genes verified the accuracy of the PCR products. Conclusions: According to our results, blaTEM-116 was the most frequent isolated ESBL gene among the P. aeruginosa strains isolated from patients.
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Affiliation(s)
- Mohmmad Bokaeian
- Department of Microbiology, School of Medicine, Zahedan University of Medical Sciences, Zahedan, IR Iran
- Research Center for Infectious Diseases and Tropical Medicine, Zahedan University of Medical Sciences, Zahedan, IR Iran
| | - Shahram Shahraki Zahedani
- Department of Microbiology, School of Medicine, Zahedan University of Medical Sciences, Zahedan, IR Iran
| | - Morteza Soltanian Bajgiran
- Department of Microbiology, School of Medicine, Zahedan University of Medical Sciences, Zahedan, IR Iran
- Corresponding author: Morteza Soltanian Bajgiran, , Department of Microbiology, Zahedan University of Medical Sciences, Zahedan, IR Iran. Tel: +98-5413414558, Fax: +98-5413425723, E-mail:
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244
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Powers RA, Swanson HC, Taracila MA, Florek NW, Romagnoli C, Caselli E, Prati F, Bonomo RA, Wallar BJ. Biochemical and structural analysis of inhibitors targeting the ADC-7 cephalosporinase of Acinetobacter baumannii. Biochemistry 2014; 53:7670-9. [PMID: 25380506 PMCID: PMC4263437 DOI: 10.1021/bi500887n] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
β-Lactam
resistance in Acinetobacter baumannii presents one
of the greatest challenges to contemporary antimicrobial chemotherapy.
Much of this resistance to cephalosporins derives from the expression
of the class C β-lactamase enzymes, known as Acinetobacter-derived cephalosporinases (ADCs). Currently, β-lactamase inhibitors
are structurally similar to β-lactam substrates and are not
effective inactivators of this class C cephalosporinase. Herein, two boronic acid transition state inhibitors
(BATSIs S02030 and SM23) that are chemically distinct from β-lactams
were designed and tested for inhibition of ADC enzymes. BATSIs SM23
and S02030 bind with high affinity to ADC-7, a chromosomal cephalosporinase
from Acinetobacter baumannii (Ki = 21.1 ± 1.9 nM and 44.5 ± 2.2 nM, respectively).
The X-ray crystal structures of ADC-7 were determined in both the
apo form (1.73 Å resolution) and in complex with S02030 (2.0
Å resolution). In the complex, S02030 makes several canonical
interactions: the O1 oxygen of S02030 is bound in the oxyanion hole,
and the R1 amide group makes key interactions with conserved residues
Asn152 and Gln120. In addition, the carboxylate group of the inhibitor
is meant to mimic the C3/C4 carboxylate found
in β-lactams. The C3/C4 carboxylate recognition
site in class C enzymes is comprised of Asn346 and Arg349 (AmpC numbering),
and these residues are conserved in ADC-7. Interestingly, in the ADC-7/S02030
complex, the inhibitor carboxylate group is observed to interact with
Arg340, a residue that distinguishes ADC-7 from the related class
C enzyme AmpC. A thermodynamic analysis suggests that ΔH driven compounds may be optimized to generate
new lead agents. The ADC-7/BATSI complex provides insight into recognition
of non-β-lactam inhibitors by ADC enzymes and offers a starting
point for the structure-based optimization of this class of novel
β-lactamase inhibitors against a key resistance target.
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Affiliation(s)
- Rachel A Powers
- Department of Chemistry, Grand Valley State University , 1 Campus Drive, Allendale, Michigan 49401, United States
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245
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Pletzer D, Lafon C, Braun Y, Köhler T, Page MGP, Mourez M, Weingart H. High-throughput screening of dipeptide utilization mediated by the ABC transporter DppBCDF and its substrate-binding proteins DppA1-A5 in Pseudomonas aeruginosa. PLoS One 2014; 9:e111311. [PMID: 25338022 PMCID: PMC4206461 DOI: 10.1371/journal.pone.0111311] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Accepted: 09/23/2014] [Indexed: 11/18/2022] Open
Abstract
In this study, we show that the dppBCDF operon of Pseudomonas aeruginosa PA14 encodes an ABC transporter responsible for the utilization of di/tripeptides. The substrate specificity of ABC transporters is determined by its associated substrate-binding proteins (SBPs). Whereas in E. coli only one protein, DppA, determines the specificity of the transporter, five orthologous SBPs, DppA1-A5 are present in P. aeruginosa. Multiple SBPs might broaden the substrate specificity by increasing the transporter capacity. We utilized the Biolog phenotype MicroArray technology to investigate utilization of di/tripeptides in mutants lacking either the transport machinery or all of the five SBPs. This high-throughput method enabled us to screen hundreds of dipeptides with various side-chains, and subsequently, to determine the substrate profile of the dipeptide permease. The substrate spectrum of the SBPs was elucidated by complementation of a penta mutant, deficient of all five SBPs, with plasmids carrying individual SBPs. It became apparent that some dipeptides were utilized with different affinity for each SBP. We found that DppA2 shows the highest flexibility on substrate recognition and that DppA2 and DppA4 have a higher tendency to utilize tripeptides. DppA5 was not able to complement the penta mutant under our screening conditions. Phaseolotoxin, a toxic tripeptide inhibiting the enzyme ornithine carbamoyltransferase, is also transported into P. aeruginosa via the DppBCDF permease. The SBP DppA1, and with much greater extend DppA3, are responsible for delivering the toxin to the permease. Our results provide a first overview of the substrate pattern of the ABC dipeptide transport machinery in P. aeruginosa.
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Affiliation(s)
- Daniel Pletzer
- Jacobs University Bremen, School of Engineering and Science, Bremen, Germany
| | - Corinne Lafon
- Sanofi-Aventis R&D, Infectious Diseases Therapeutic Unit, Toulouse, France
| | - Yvonne Braun
- Jacobs University Bremen, School of Engineering and Science, Bremen, Germany
| | - Thilo Köhler
- Department of Microbiology and Molecular Medicine and Service of Infectious Diseases, University Hospital Geneva, Geneva, Switzerland
| | | | - Michael Mourez
- Sanofi-Aventis R&D, Infectious Diseases Therapeutic Unit, Toulouse, France
| | - Helge Weingart
- Jacobs University Bremen, School of Engineering and Science, Bremen, Germany
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Kamoshida G, Kikuchi-Ueda T, Tansho-Nagakawa S, Nakano R, Nakano A, Kikuchi H, Ubagai T, Ono Y. Acinetobacter baumannii escape from neutrophil extracellular traps (NETs). J Infect Chemother 2014; 21:43-9. [PMID: 25287154 DOI: 10.1016/j.jiac.2014.08.032] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Revised: 08/28/2014] [Accepted: 08/29/2014] [Indexed: 01/09/2023]
Abstract
Acinetobacter baumannii and Pseudomonas aeruginosa are the same aerobic gram-negative bacillus and are usually harmless but cause infectious diseases in compromised hosts. Neutrophils play a critical role in infective protection against the extracellular growth of bacteria. Recently, a new biological defense mechanism called neutrophil extracellular traps (NETs) has been attracting attention. In present study, we investigated the responsiveness of neutrophils to A. baumannii and P. aeruginosa, focusing on NET formation. Neutrophils were co-cultured with A. baumannii or P. aeruginosa, and then DNA, histone and neutrophil elastase were stained, and the formation of NETs was evaluated. Neutrophils stimulated with A. baumannii had spread, but their shapes was maintained, and the nucleus was observed as clearly as that in non-stimulated neutrophils. However, neutrophils stimulated with P. aeruginosa did not maintain their cellular morphology, and the nucleus was disrupted with DNA, histones, and neutrophil elastase released into the extracellular space. These results suggest that A. baumannii does not induce NET formation, in contrast to P. aeruginosa. In addition, we measured expression of myeloperoxidase (MPO), reactive oxygen species (ROS) and superoxide in neutrophils, and we found that these expression in P. aeruginosa-stimulated neutrophils was stronger than that in A. baumannii-stimulated neutrophils. Furthermore, A. baumannii was not killed by neutrophils, in contrast to P. aeruginosa. In this study, we show that the reactivity of neutrophils and their biological defense mechanism are different between A. baumannii and P. aeruginosa, which is important for understanding the pathogenicity of these bacteria.
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Affiliation(s)
- Go Kamoshida
- Department of Microbiology and Immunology, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi-ku, Tokyo 173-8605, Japan.
| | - Takane Kikuchi-Ueda
- Department of Microbiology and Immunology, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi-ku, Tokyo 173-8605, Japan
| | - Shigeru Tansho-Nagakawa
- Department of Microbiology and Immunology, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi-ku, Tokyo 173-8605, Japan
| | - Ryuichi Nakano
- Department of Microbiology and Immunology, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi-ku, Tokyo 173-8605, Japan
| | - Akiyo Nakano
- Department of Microbiology and Immunology, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi-ku, Tokyo 173-8605, Japan
| | - Hirotoshi Kikuchi
- Department of Microbiology and Immunology, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi-ku, Tokyo 173-8605, Japan
| | - Tsuneyuki Ubagai
- Department of Microbiology and Immunology, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi-ku, Tokyo 173-8605, Japan
| | - Yasuo Ono
- Department of Microbiology and Immunology, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi-ku, Tokyo 173-8605, Japan
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Coutinho FH, Silveira CB, Pinto LH, Salloto GRB, Cardoso AM, Martins OB, Vieira RP, Clementino MM. Antibiotic resistance is widespread in urban aquatic environments of Rio de Janeiro, Brazil. MICROBIAL ECOLOGY 2014; 68:441-452. [PMID: 24821495 DOI: 10.1007/s00248-014-0422-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Accepted: 04/11/2014] [Indexed: 06/03/2023]
Abstract
Bacterial resistance to antibiotics has become a public health issue. Over the years, pathogenic organisms with resistance traits have been studied due to the threat they pose to human well-being. However, several studies raised awareness to the often disregarded importance of environmental bacteria as sources of resistance mechanisms. In this work, we analyze the diversity of antibiotic-resistant bacteria occurring in aquatic environments of the state of Rio de Janeiro, Brazil, that are subjected to distinct degrees of anthropogenic impacts. We access the diversity of aquatic bacteria capable of growing in increasing ampicillin concentrations through 16S rRNA gene libraries. This analysis is complemented by the characterization of antibiotic resistance profiles of isolates obtained from urban aquatic environments. We detect communities capable of tolerating antibiotic concentrations up to 600 times higher than the clinical levels. Among the resistant organisms are included potentially pathogenic species, some of them classified as multiresistant. Our results extend the knowledge of the diversity of antibiotic resistance among environmental microorganisms and provide evidence that the diversity of drug-resistant bacteria in aquatic habitats can be influenced by pollution.
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Affiliation(s)
- Felipe H Coutinho
- Instituto de Bioquímica Médica, Universidade Federal do Rio de Janeiro, UFRJ, Rio de Janeiro, Brazil,
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248
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The hierarchy quorum sensing network in Pseudomonas aeruginosa. Protein Cell 2014; 6:26-41. [PMID: 25249263 PMCID: PMC4286720 DOI: 10.1007/s13238-014-0100-x] [Citation(s) in RCA: 750] [Impact Index Per Article: 75.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Accepted: 08/28/2014] [Indexed: 12/13/2022] Open
Abstract
Pseudomonas aeruginosa causes severe and persistent infections in immune compromised individuals and cystic fibrosis sufferers. The infection is hard to eradicate as P. aeruginosa has developed strong resistance to most conventional antibiotics. The problem is further compounded by the ability of the pathogen to form biofilm matrix, which provides bacterial cells a protected environment withstanding various stresses including antibiotics. Quorum sensing (QS), a cell density-based intercellular communication system, which plays a key role in regulation of the bacterial virulence and biofilm formation, could be a promising target for developing new strategies against P. aeruginosa infection. The QS network of P. aeruginosa is organized in a multi-layered hierarchy consisting of at least four interconnected signaling mechanisms. Evidence is accumulating that the QS regulatory network not only responds to bacterial population changes but also could react to environmental stress cues. This plasticity should be taken into consideration during exploration and development of anti-QS therapeutics.
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249
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Properties of AdeABC and AdeIJK efflux systems of Acinetobacter baumannii compared with those of the AcrAB-TolC system of Escherichia coli. Antimicrob Agents Chemother 2014; 58:7250-7. [PMID: 25246403 DOI: 10.1128/aac.03728-14] [Citation(s) in RCA: 176] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Acinetobacter baumannii contains RND-family efflux systems AdeABC and AdeIJK, which pump out a wide range of antimicrobial compounds, as judged from the MIC changes occurring upon deletion of the responsible genes. However, these studies may miss changes because of the high backgrounds generated by the remaining pumps and by β-lactamases, and it is unclear how the activities of these pumps compare quantitatively with those of the well-studied AcrAB-TolC system of Escherichia coli. We expressed adeABC and adeIJK of A. baumannii, as well as E. coli acrAB, in an E. coli host from which acrAB was deleted. The A. baumannii pumps were functional in E. coli, and the MIC changes that were observed largely confirmed the substrate range already reported, with important differences. Thus, the AdeABC system pumped out all β-lactams, an activity that was often missed in deletion studies. When the expression level of the pump genes was adjusted to a similar level for a comparison with AcrAB-TolC, we found that both A. baumannii efflux systems pumped out a wide range of compounds, but AdeABC was less effective than AcrAB-TolC in the extrusion of lipophilic β-lactams, novobiocin, and ethidium bromide, although it was more effective at tetracycline efflux. AdeIJK was remarkably more effective than a similar level of AcrAB-TolC in the efflux of β-lactams, novobiocin, and ethidium bromide, although it was less so in the efflux of erythromycin. These results thus allow us to compare these efflux systems on a quantitative basis, if we can assume that the heterologous systems are fully functional in the E. coli host.
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250
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Lutsar I, Telling K, Metsvaht T. Treatment option for sepsis in children in the era of antibiotic resistance. Expert Rev Anti Infect Ther 2014; 12:1237-52. [PMID: 25189378 DOI: 10.1586/14787210.2014.956093] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Sepsis caused by multidrug-resistant microorganisms is one of the most serious infectious diseases of childhood and poses significant challenges for pediatricians involved in management of critically ill children. This review discusses the use of pharmacokinetic/dynamic principles (i.e., prolonged infusion of β-lactams and vancomycin, once-daily administration of aminoglycosides and rationale of therapeutic drug monitoring) when prescribing antibiotics to critically ill patients. The potential of 'old' agents (i.e., colistin, fosfomycin) and newly approved antibiotics is critically reviewed. The pros and cons of combination antibacterial therapy are discussed and finally suggestions for the treatment of sepsis caused by multidrug-resistant organisms are provided.
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Affiliation(s)
- Irja Lutsar
- Institute of Medical Microbiology, University of Tartu, Ravila 19, 50411 Tartu, Estonia
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