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Tofteland S, Dahl KH, Aasnæs B, Sundsfjord A, Naseer U. A nationwide study of mechanisms conferring reduced susceptibility to extended-spectrum cephalosporins in clinical Escherichia coli and Klebsiella spp. isolates. ACTA ACUST UNITED AC 2012; 44:927-33. [DOI: 10.3109/00365548.2012.707330] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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102
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Development of a TaqMan multiplex PCR assay for detection of plasmid-mediated ampC β-lactamase genes. J Clin Microbiol 2012; 50:3722-5. [PMID: 22895035 DOI: 10.1128/jcm.02038-12] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A multiplex, real-time TaqMan assay was designed to identify clinical isolates carrying plasmid-mediated ampC genes. The specificity and sensitivity of this assay were 100% when testing characterized AmpC/non-AmpC-producing isolates and randomly selected clinical isolates. This is a rapid assay that can be performed in a clinical microbiology laboratory.
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103
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Srinivasan VB, Venkataramaiah M, Mondal A, Vaidyanathan V, Govil T, Rajamohan G. Functional characterization of a novel outer membrane porin KpnO, regulated by PhoBR two-component system in Klebsiella pneumoniae NTUH-K2044. PLoS One 2012; 7:e41505. [PMID: 22848515 PMCID: PMC3405095 DOI: 10.1371/journal.pone.0041505] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2012] [Accepted: 06/22/2012] [Indexed: 02/03/2023] Open
Abstract
Background The diffusion of antibiotics through the outer membrane is primarily affected by the porin super family, changes contribute to antibiotic resistance. Recently we demonstrated that the CpxAR two-component signaling system alters the expression of an uncharacterized porin OmpCKP, to mediate antimicrobial resistance in K. pneumoniae. Principal Findings In this study, functional characterization of the putative porin OmpCKP (denoted kpnO) with respect to antimicrobial susceptibility and virulence was evaluated by generating an isogenic mutant, ΔkpnO in a clinical isolate of K. pneumoniae. Estimation of uronic acid content confirmed that ΔkpnO produced ∼2.0 fold lesser capsular polysaccharide than the wild-type. The ΔkpnO displayed higher sensitivity to hyper osmotic and bile conditions. Disruption of kpnO increased the susceptibility of K. pneumoniae to oxidative and nitrostative stress by ∼1.6 fold and >7 fold respectively. The loss of the Klebsiella porin led to an increase in the minimum inhibitory concentration of tetracycline (3-fold), nalidixic acid (4-fold), tobramycin (4-fold), streptomycin (10-fold), and spectinomycin (10-fold), which could be restored following complementation. The single deletion of kpnO reduced the survival of the pathogen by 50% when exposed to disinfectants. In Caenorhabditis elegans model, the kpnO mutant exhibited significantly (P<0.01) lower virulence. To dissect the role of PhoBR signaling system in regulating the expression of the kpnO, a phoBKP isogenic mutant was constructed. The phoBKP mutant exhibited impaired gastrointestinal stress response and decreased antimicrobial susceptibility. The mRNA levels of kpnO were found to be 4-fold less in phoBKP mutant compared to wild type. A regulatory role of PhoBKP for the expression of kpnO was further supported by the specific binding of PhoBKP to the putative promoter of kpnO. Conclusions and Significance Loss of PhoBR regulated porin KpnO resulted in increased antimicrobial resistance, increased susceptibility to gastrointestinal stress, and reduced virulence in K. pneumoniae NTUH-K2044.
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Affiliation(s)
- Vijaya Bharathi Srinivasan
- Council of Scientific Industrial Research, Institute of Microbial Technology, Sector 39 A, Chandigarh, India
- * E-mail: (VBS); (GR)
| | - Manjunath Venkataramaiah
- Council of Scientific Industrial Research, Institute of Microbial Technology, Sector 39 A, Chandigarh, India
| | - Amitabha Mondal
- Council of Scientific Industrial Research, Institute of Microbial Technology, Sector 39 A, Chandigarh, India
| | - Vasanth Vaidyanathan
- Council of Scientific Industrial Research, Institute of Microbial Technology, Sector 39 A, Chandigarh, India
| | - Tanvi Govil
- Council of Scientific Industrial Research, Institute of Microbial Technology, Sector 39 A, Chandigarh, India
| | - Govindan Rajamohan
- Council of Scientific Industrial Research, Institute of Microbial Technology, Sector 39 A, Chandigarh, India
- * E-mail: (VBS); (GR)
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Rosenberger LH, Riccio LM, Campbell KT, Politano AD, Sawyer RG. Quarantine, isolation, and cohorting: from cholera to Klebsiella. Surg Infect (Larchmt) 2012; 13:69-73. [PMID: 22472002 DOI: 10.1089/sur.2011.067] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Isolation is defined as the separation of persons with communicable diseases from those who are healthy. This public health practice, along with quarantine, is used to limit the transmission of infectious diseases and provides the foundation of current-day cohorting. METHODS Review of the pertinent English-language literature. RESULTS Mass isolation developed during the medieval Black Death outbreaks in order to protect ports from the transmission of epidemics. In the mid-1800s, infectious disease hospitals were opened. It now is clear that isolation and cohorting of patients and staff interrupts the transmission of disease. Over the next century, with the discovery of penicillin and vaccines against many infectious agents, the contagious disease hospitals began to close. Today, we find smaller outbreaks of microorganisms that have acquired substantial resistance to antimicrobial agents. In the resource-limited hospital, a dedicated area or region of a unit may suffice to separate affected from unaffected patients. CONCLUSION Quarantine, or cohorting when patients are infected with the same pathogen, interrupts the spread of infections, just as the contagious disease hospitals did during the epidemics of the 18th and 19th centuries.
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Affiliation(s)
- Laura H Rosenberger
- Department of Surgery, University of Virginia Health System, Charlottesville, Virginia, USA.
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105
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Nordmann P, Dortet L, Poirel L. Carbapenem resistance in Enterobacteriaceae: here is the storm! Trends Mol Med 2012; 18:263-72. [PMID: 22480775 DOI: 10.1016/j.molmed.2012.03.003] [Citation(s) in RCA: 678] [Impact Index Per Article: 56.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2011] [Revised: 02/29/2012] [Accepted: 03/08/2012] [Indexed: 12/21/2022]
Abstract
The current worldwide emergence of resistance to the powerful antibiotic carbapenem in Enterobacteriaceae constitutes an important growing public health threat. Sporadic outbreaks or endemic situations with enterobacterial isolates not susceptible to carbapenems are now reported not only in hospital settings but also in the community. Acquired class A (KPC), class B (IMP, VIM, NDM), or class D (OXA-48, OXA-181) carbapenemases, are the most important determinants sustaining resistance to carbapenems. The corresponding genes are mostly plasmid-located and associated with various mobile genetic structures (insertion sequences, integrons, transposons), further enhancing their spread. This review summarizes the current knowledge on carbapenem resistance in Enterobacteriaceae, including activity, distribution, clinical impact, and possible novel antibiotic pathways.
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Affiliation(s)
- Patrice Nordmann
- Service de Bactériologie-Virologie, INSERM U914 Emerging Resistance to Antibiotic, Hôpital de Bicêtre, Assistance Publique/Hôpitaux de Paris, Faculté de Médecine Paris Sud, K.-Bicêtre, 94275 Le Kremlin-Bicêtre Cedex, France.
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106
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Francis RO, Wu F, Della-Latta P, Shi J, Whittier S. Rapid detection of Klebsiella pneumoniae carbapenemase genes in enterobacteriaceae directly from blood culture bottles by real-time PCR. Am J Clin Pathol 2012; 137:627-32. [PMID: 22431540 DOI: 10.1309/ajcp9snhjg2qglwu] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
Abstract
Klebsiella pneumoniae carbapenemase (KPC)-producing Enterobacteriaceae are endemic in New York City hospitals and have been associated with serious infections globally. A real-time polymerase chain reaction (RT-PCR) assay was developed to detect carbapenem resistance attributable to KPC from blood culture bottles positive for gram-negative bacilli. Culture confirmation of carbapenemase production included automated imipenem and meropenem susceptibility testing and ertapenem susceptibility testing by disk-diffusion. A total of 323 Enterobacteriaceae isolates were tested, of which 8.7% (n = 28) demonstrated carbapenem-resistance by automated and manual susceptibility testing methods or by RT-PCR. The sensitivity, specificity, and positive and negative predictive values of the RT-PCR assay when compared with the automated method were 92.9%, 99.3%, 92.9%, and 99.3%, respectively, and 96.4%, 99.7%, 96.4%, and 99.7%, respectively, when compared with the ertapenem disk-diffusion method. RT-PCR is a rapid and reliable means of detecting carbapenem resistance due to KPC-plasmids in Enterobacteriaceae directly from blood culture bottles.
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107
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Evaluation of four phenotypic methods to detect plasmid-mediated AmpC β-lactamases in clinical isolates. Eur J Clin Microbiol Infect Dis 2012; 31:2037-43. [PMID: 22278294 DOI: 10.1007/s10096-011-1537-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2011] [Accepted: 12/21/2011] [Indexed: 10/14/2022]
Abstract
Four phenotypic methods (three dimensional test, AmpC test, cloxacillin synergy test and cefotetan/cefotetan-cloxacillin E-test) to detect plasmid-mediated AmpC β-lactamases (pAmpC) were compared in 125 clinical Enterobacteriaceae isolates with AmpC profile: 74 E. coli (bla (CMY-2): 70; bla (DHA-1): 4), five K. pneumoniae (bla (CMY-2): 2; bla (DHA-1): 3), six P. mirabilis (bla (CMY-2): 6) and 40 negative isolates for pAmpC β-lactamases. All evaluated methods showed a good sensitivity (>95%) but low values of specificity (<60%) in E. coli, explained by an increase of AmpC expression caused by chromosomal ampC promoter/attenuator mutations (-42, -18, -1, +58, predominantly). The cefotetan/cefotetan-cloxacillin or cloxacillin synergy test may be advocated as phenotypic screening test, and the AmpC test as confirmatory test for detection of pAmpC in isolates that lack or minimally express chromosomally encoded AmpC β-lactamases. In the case of E. coli, the phenotypic evaluated tests were not able to differentiate between chromosomal ampC overexpression or acquisition of plasmid-encoded ampC genes.
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108
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Cefoxitin as an alternative to carbapenems in a murine model of urinary tract infection due to Escherichia coli harboring CTX-M-15-type extended-spectrum β-lactamase. Antimicrob Agents Chemother 2012; 56:1376-81. [PMID: 22214774 DOI: 10.1128/aac.06233-11] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
We investigated the efficiency of the cephamycin cefoxitin as an alternative to carbapenems for the treatment of urinary tract infections (UTIs) due to Escherichia coli producing CTX-M-type extended-spectrum β-lactamases. The susceptible, UTI-inducing E. coli CFT073-RR strain and its transconjugant CFT073-RR Tc (pbla(CTX-M-15)), harboring a bla(CTX-M-15) carrying-plasmid, were used for all experiments. MICs of cefoxitin (FOX), ceftriaxone (CRO), imipenem (IMP), and ertapenem (ETP) for CFT073-RR and CFT073-RR Tc (pbla(CTX-M-15)) were 4 and 4, 0.125 and 512, 0.5 and 0.5, and 0.016 and 0.032 μg/ml, respectively. Bactericidal activity was similarly achieved in vitro against the two strains after 3 h of exposure to concentrations of FOX, IMI, and ETP that were 2 times the MIC, whereas CRO was not bactericidal against CFT073-RR Tc (pbla(CTX-M-15)). The frequencies of spontaneous mutants of the 2 strains were not higher for FOX than for IMP or ETP. In the murine model of UTIs, mice infected for 5 days were treated over 24 h. Therapeutic regimens in mice (200 mg/kg of body weight every 3 h or 4 h for FOX, 70 mg/kg every 6 h for CRO, 100 mg/kg every 2 h for IMP, and 100 mg/kg every 4 h for ETP) were chosen in order to reproduce the percentage of time that free-drug concentrations above the MIC are obtained in humans with standard regimens. All antibiotic regimens produced a significant reduction in bacterial counts (greater than 2 log(10) CFU) in kidneys and bladders for both strains (P < 0.001) without selecting resistant mutants in vivo, but the reduction obtained with CRO against CFT073-RR Tc (pbla(CTX-M-15)) in kidneys was significantly lower than that obtained with FOX. In conclusion, FOX appears to be an effective therapeutic alternative to carbapenems for the treatment of UTIs due to CTX-M-producing E. coli.
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109
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Roh KH, Song W, Chung HS, Lee YS, Yum JH, Yi HN, Chun JS, Yong D, Lee K, Chong Y. Chromosomal cephalosporinase in Enterobacter hormaechei as an ancestor of ACT-1 plasmid-mediated AmpC β-lactamase. J Med Microbiol 2012; 61:94-100. [DOI: 10.1099/jmm.0.032573-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Kyoung Ho Roh
- Department of Laboratory Medicine, Korea University College of Medicine, Seoul, Republic of Korea
| | - Wonkeun Song
- Department of Laboratory Medicine, Hallym University College of Medicine, Seoul, Republic of Korea
| | - Hae-Sun Chung
- Department of Laboratory Medicine, Research Institute of Bacterial Resistance, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Yang Soon Lee
- Department of Laboratory Medicine, Research Institute of Bacterial Resistance, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Jong Hwa Yum
- Department of Clinical Laboratory Science, Dong-eui University, Busan, Republic of Korea
| | - Ha Na Yi
- School of Biological Sciences and Institute of Microbiology, Seoul National University, Seoul, Republic of Korea
| | - Jong Sik Chun
- School of Biological Sciences and Institute of Microbiology, Seoul National University, Seoul, Republic of Korea
| | - Dongeun Yong
- Department of Laboratory Medicine, Research Institute of Bacterial Resistance, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Kyungwon Lee
- Department of Laboratory Medicine, Research Institute of Bacterial Resistance, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Yunsop Chong
- Department of Laboratory Medicine, Research Institute of Bacterial Resistance, Yonsei University College of Medicine, Seoul, Republic of Korea
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110
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Papp-Wallace KM, Endimiani A, Taracila MA, Bonomo RA. Carbapenems: past, present, and future. Antimicrob Agents Chemother 2011; 55:4943-60. [PMID: 21859938 PMCID: PMC3195018 DOI: 10.1128/aac.00296-11] [Citation(s) in RCA: 877] [Impact Index Per Article: 67.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
In this review, we summarize the current "state of the art" of carbapenem antibiotics and their role in our antimicrobial armamentarium. Among the β-lactams currently available, carbapenems are unique because they are relatively resistant to hydrolysis by most β-lactamases, in some cases act as "slow substrates" or inhibitors of β-lactamases, and still target penicillin binding proteins. This "value-added feature" of inhibiting β-lactamases serves as a major rationale for expansion of this class of β-lactams. We describe the initial discovery and development of the carbapenem family of β-lactams. Of the early carbapenems evaluated, thienamycin demonstrated the greatest antimicrobial activity and became the parent compound for all subsequent carbapenems. To date, more than 80 compounds with mostly improved antimicrobial properties, compared to those of thienamycin, are described in the literature. We also highlight important features of the carbapenems that are presently in clinical use: imipenem-cilastatin, meropenem, ertapenem, doripenem, panipenem-betamipron, and biapenem. In closing, we emphasize some major challenges and urge the medicinal chemist to continue development of these versatile and potent compounds, as they have served us well for more than 3 decades.
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Affiliation(s)
- Krisztina M. Papp-Wallace
- Research Service, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, Ohio 44106
- Departments of Medicine
| | - Andrea Endimiani
- Research Service, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, Ohio 44106
- Institute for Infectious Diseases, University of Bern 3010, Bern, Switzerland
- Departments of Medicine
| | | | - Robert A. Bonomo
- Research Service, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, Ohio 44106
- Departments of Medicine
- Pharmacology
- Molecular Biology and Microbiology, Case Western Reserve University, Cleveland, Ohio 44106
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111
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Gupta N, Limbago BM, Patel JB, Kallen AJ. Carbapenem-resistant Enterobacteriaceae: epidemiology and prevention. Clin Infect Dis 2011; 53:60-7. [PMID: 21653305 DOI: 10.1093/cid/cir202] [Citation(s) in RCA: 726] [Impact Index Per Article: 55.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Over the past 10 years, dissemination of Klebsiella pneumoniae carbapenemase (KPC) has led to an increase in the prevalence of carbapenem-resistant Enterobacteriaceae (CRE) in the United States. Infections caused by CRE have limited treatment options and have been associated with high mortality rates. In the previous year, other carbapenemase subtypes, including New Delhi metallo-β-lactamase, have been identified among Enterobacteriaceae in the United States. Like KPC, these enzymes are frequently found on mobile genetic elements and have the potential to spread widely. As a result, preventing both CRE transmission and CRE infections have become important public health objectives. This review describes the current epidemiology of CRE in the United States and highlights important prevention strategies.
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Affiliation(s)
- Neil Gupta
- Epidemic Intelligence Service, Centers for Disease Control and Prevention, 1600 Clifton Road NE, MS A-35, Atlanta, GA 30333, USA.
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112
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IMP-producing carbapenem-resistant Klebsiella pneumoniae in the United States. J Clin Microbiol 2011; 49:4239-45. [PMID: 21998425 DOI: 10.1128/jcm.05297-11] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The emergence and spread of carbapenem-resistant Enterobacteriaceae (CRE) producing acquired carbapenemases have created a global public health crisis. In the United States, CRE producing the Klebsiella pneumoniae carbapenemase (KPC) are increasingly common and are endemic in some regions. Metallo-β-lactamase (MBL)-producing CRE have recently been reported in the United States among patients who received medical care in countries where such organisms are common. Here, we describe three carbapenem-resistant K. pneumoniae isolates recovered from pediatric patients at a single U.S. health care facility, none of whom had a history of international travel. The isolates were resistant to carbapenems but susceptible to aztreonam, trimethoprim-sulfamethoxazole, and fluoroquinolones. The three isolates were closely related to each other by pulsed-field gel electrophoresis and contained a common plasmid. PCR and sequence analysis confirmed that these isolates produce IMP-4, an MBL carbapenemase not previously published as present among Enterobacteriaceae in the United States.
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113
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Patel G, Bonomo RA. Status report on carbapenemases: challenges and prospects. Expert Rev Anti Infect Ther 2011; 9:555-70. [PMID: 21609267 DOI: 10.1586/eri.11.28] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Antimicrobial resistance in hospital and community-onset bacterial infections is a significant source of patient morbidity and mortality. In the past decade, we have witnessed the increasing recovery of carbapenem-resistant Gram-negative bacteria. For many isolates, carbapenem resistance is due to the production of carbapenemases, β-lactamases that can inactivate carbapenems and frequently other β-lactam antibiotics. Currently, these enzymes are mainly found in three different β-lactamase classes (class A, B and D). Regardless of the molecular classification, there are few antimicrobials available to treat infections with these organisms and data regarding agents in development are limited to in vitro studies. This article focuses on the epidemiology of carbapenemase-producing Gram-negative bacteria. We also review available agents and those in development with potential activity against this evolving threat.
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Affiliation(s)
- Gopi Patel
- Department of Medicine, Mount Sinai School of Medicine, New York, NY, USA
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114
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OmpK26, a novel porin associated with carbapenem resistance in Klebsiella pneumoniae. Antimicrob Agents Chemother 2011; 55:4742-7. [PMID: 21807980 DOI: 10.1128/aac.00309-11] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Clinical isolates of Klebsiella pneumoniae resistant to carbapenems are being isolated with increasing frequency. Loss of the expression of the major nonspecific porins OmpK35/36 is a frequent feature in these isolates. In this study, we looked for porins that could compensate for the loss of the major porins in carbapenem-resistant organisms. Comparison of the outer membrane proteins from two K. pneumoniae clinical isogenic isolates that are susceptible (KpCS-1) and resistant (KpCR-1) to carbapenems revealed the absence of OmpK35/36 and the presence of a new 26-kDa protein in the resistant isolate. An identical result was obtained when another pair of isogenic isolates that are homoresistant (Kpn-3) and heteroresistant (Kpn-17) to carbapenems were compared. Mass spectrometry and DNA sequencing analysis demonstrated that this new protein, designated OmpK26, is a small monomeric oligogalacturonate-specific porin that belongs to the KdgM family of porins. Insertion-duplication mutagenesis of the OmpK26 coding gene, yjhA, in the carbapenem-resistant, porin-deficient isolate KpCR-1 caused the expression of OmpK36 and the reversion to the carbapenem-susceptible phenotype, suggesting that OmpK26 is indispensable for KpCR-1 to lose OmpK36 and become resistant to these antibiotics. Moreover, loss of the major porin and expression of OmpK26 reduced in vitro fitness and attenuated virulence in a murine model of acute systemic infection. Altogether, these results indicate that expression of the oligogalacturonate-specific porin OmpK26 compensates for the absence of OmpK35/36 and allows carbapenem resistance in K. pneumoniae but cannot restore the fitness of the microorganism.
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115
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116
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First outbreak of a plasmid-mediated carbapenem-hydrolyzing OXA-48 beta-lactamase in Klebsiella pneumoniae in Spain. Antimicrob Agents Chemother 2011; 55:4398-401. [PMID: 21746954 DOI: 10.1128/aac.00329-11] [Citation(s) in RCA: 108] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Twenty Klebsiella pneumoniae isolates producing OXA-48 were collected from April 2009 to September 2010. Strains were clonally related and coproduced a CTX-M-15 β-lactamase. A conjugative plasmid of circa 70 kb carrying bla(OXA-48) was identified. Eleven isolates showed low-level resistance to carbapenems, whereas nine showed high-level resistance. Decreased expression of OmpK36 was related to high-level resistance to carbapenems. The isolates belonged to sequence type 101 (ST101). This is the first outbreak caused by an OXA-48-producing K. pneumoniae strain in Spain.
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117
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Clark C, McGhee P, Appelbaum PC, Kosowska-Shick K. Multistep resistance development studies of ceftaroline in gram-positive and -negative bacteria. Antimicrob Agents Chemother 2011; 55:2344-51. [PMID: 21343467 PMCID: PMC3088212 DOI: 10.1128/aac.01602-10] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2010] [Accepted: 02/09/2011] [Indexed: 11/20/2022] Open
Abstract
Ceftaroline, the active component of the prodrug ceftaroline fosamil, is a novel broad-spectrum cephalosporin with bactericidal activity against Gram-positive and -negative isolates. This study evaluated the potential for ceftaroline and comparator antibiotics to select for clones of Streptococcus pneumoniae, Streptococcus pyogenes, Haemophilus influenzae, Moraxella catarrhalis, Klebsiella pneumoniae, Staphylococcus aureus, and Enterococcus faecalis with elevated MICs. S. pneumoniae and S. pyogenes isolates in the present study were highly susceptible to ceftaroline (MIC range, 0.004 to 0.25 μg/ml). No streptococcal strains yielded ceftaroline clones with increased MICs (defined as an increase in MIC of >4-fold) after 50 daily passages. Ceftaroline MICs for H. influenzae and M. catarrhalis were 0.06 to 2 μg/ml for four strains and 8 μg/ml for a β-lactamase-positive, efflux-positive H. influenzae with a mutation in L22. One H. influenzae clone with an increased ceftaroline MIC (quinolone-resistant, β-lactamase-positive) was recovered after 20 days. The ceftaroline MIC for this isolate increased 16-fold, from 0.06 to 1 μg/ml. MICs for S. aureus ranged from 0.25 to 1 μg/ml. No S. aureus isolates tested with ceftaroline had clones with increased MIC (>4-fold) after 50 passages. Two E. faecalis isolates tested had ceftaroline MICs increased from 1 to 8 μg/ml after 38 days and from 4 to 32 μg/ml after 41 days, respectively. The parental ceftaroline MIC for the one K. pneumoniae extended-spectrum β-lactamase-negative isolate tested was 0.5 μg/ml and did not change after 50 daily passages.
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118
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Chen JH, Lin JC, Chang JL, Tsai YK, Siu LK. Different culture medium formulations induce variant protein expression patterns of outer membrane porins in Klebsiella pneumoniae. J Chemother 2011; 23:9-12. [PMID: 21482487 DOI: 10.1179/joc.2011.23.1.9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
Outer membrane porin (OMP) expression has been shown to play an important role in antimicrobial resistance. In this study, we observed that OmpK35 of Klebsiella pneumoniae had varied expression profiles in different nutrient broths. the potential factors that could influence protein expression were assessed. K. pneumoniae (ATCC 13883) was cultured into two commercial available nutrient broths and also into solutions of the individual ingredients. To ensure that OmpK35 was detected, an OmpK35 deficient mutant was generated as control. When OmpK protein expression profiles were analyzed by SDS-PAGE, OmpK35 exhibited two different isoforms. Expression of an additional isoform-like OmpK35 protein was identified in one of the broths. No OmpK35 isoforms were observed when the individual ingredients of beef extract, casein or gelatin were used as culture medium. OmpK35 isoform expression could be repressed by adding more beef extract. In summary, OmpK can exhibit varied protein expression profiles when growing in different nutrient broths. The isoform-like protein expression of OmpK35 may lead to confusion in OmpK protein analysis.
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Affiliation(s)
- Jiun-Han Chen
- Division of Infectious Diseases, Department of Medical Laboratory Science and Biotechnology, Yuanpei University, Taiwan
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119
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Gomez E, Urban C, Mariano N, Colon-Urban R, Eng RHK, Huang DB, Chiang T. Phenotypic and genotypic screening and clonal analysis of carbapenem-resistant Klebsiella pneumoniae at a single hospital. Microb Drug Resist 2011; 17:251-7. [PMID: 21332362 DOI: 10.1089/mdr.2010.0116] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Detection of bla(KPC)-harboring Klebsiella pneumoniae (KP) in the clinical laboratory remains a difficult task. Decreased ertapenem (ERT) susceptibility has been considered one of the most sensitive phenotypic indicators of K. pneumoniae carbapenemase (KPC) production, but has been found to be nonspecific. Susceptibility testing using imipenem or meropenem lacks the sensitivity for detection of KPCs, and there is limited experience using doripenem (DOR). Fifty-five individual ERT-nonsusceptible KP isolates and 19 isolates that were ERT-susceptible, extended spectrum β-lactamase-positive KP were collected from the clinical laboratory and tested for DOR susceptibility by Etest methodology. PCR screening for bla(KPC) was performed on all specimens. All but three isolates with ERT resistance were KPC positive by PCR. Compared to PCR, ERT detection of KPC had a sensitivity of 98% and a false-positive rate of 6%. Overall, there was a 97% agreement between ERT and DOR susceptibility results. However, there was one KPC-positive isolate that was discrepant (ERT susceptible, DOR nonsusceptible by Etest). Selected isolates of KP from both groups underwent pulsed-field gel electrophoresis analysis to determine the degree of genetic relatedness of KPC-positive and KPC-negative isolates. Pulsed-field gel electrophoresis of selected KPC-positive and KPC-negative KP identified a common pattern between both groups. The resistance to DOR and/or ERT is sensitive and a specific indicator for detection of bla(KPC) in KP.
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Affiliation(s)
- Eric Gomez
- University of Medicine and Dentistry of New Jersey-New Jersey Medical School, Newark, New Jersey, USA
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120
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Sidjabat H, Nimmo GR, Walsh TR, Binotto E, Htin A, Hayashi Y, Li J, Nation RL, George N, Paterson DL. Carbapenem resistance in Klebsiella pneumoniae due to the New Delhi Metallo-β-lactamase. Clin Infect Dis 2011; 52:481-4. [PMID: 21258100 PMCID: PMC3106237 DOI: 10.1093/cid/ciq178] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2010] [Accepted: 12/03/2010] [Indexed: 11/14/2022] Open
Abstract
Carbapenem resistance in Klebsiella pneumoniae is most notably due to the K. pneumoniae carbapenemase (KPC) β-lactamase. In this report, we describe the occurrence of a newly described mechanism of carbapenem resistance, the NDM-1 β-lactamase, in a patient who received medical attention (but was not hospitalized) in India.
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Affiliation(s)
- Hanna Sidjabat
- University of Queensland Centre for Clinical Research, Queensland, Australia
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121
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Zhu YL, Zhang XN, Gao F, Cheng J, Hu LF, Ma T, Yin J, Ye Y, Li JB. ACT-6, a novel plasmid-encoded class C β-lactamase in a Klebsiella pneumoniae isolate from China. J Antibiot (Tokyo) 2011; 64:317-20. [PMID: 21304534 DOI: 10.1038/ja.2011.1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The purpose of this study was to investigate the phenotypic and molecular characterization of a novel plasmid-mediated AmpC-type β-lactamase in Klebsiella pneumoniae E701 isolated from Anhui province in China. In comparison with the ACT-1, sequence analysis revealed that there were 43 point mutations in the coding gene, and 10 of which led to amino-acid substitution. Resistance could be transferred by conjugation or transformation with plasmid DNA into E. coli JM109, which was due to the production of a β-lactamase with an isoelectric point of 8.4 named ACT-6. Cloning, expression, purification and kinetics were carried out to study the characterization of the novel AmpC-type β-lactamase. The results of MIC determinations and substrate profiles showed there was no significant difference in the activities of the novel enzyme and ACT-1. Moreover, the class 1 integron and the whole open reading frame of the novel AmpC-type β-lactamase from K.pneumoniae E701 were detectable in the same size plasmid. This is the first report on the emergence of the novel ACT-6 type β-lactamases in K. pneumoniae.
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Affiliation(s)
- Yu-lin Zhu
- Department of Infectious Diseases, the First Affiliated Hospital of Anhui Medical University, Hefei, Anhui, China
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122
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Kalpoe JS, Al Naiemi N, Poirel L, Nordmann P. Detection of an Ambler class D OXA-48-type β-lactamase in a Klebsiella pneumoniae strain in The Netherlands. J Med Microbiol 2011; 60:677-678. [PMID: 21252273 DOI: 10.1099/jmm.0.028308-0] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Traditionally, bacteria in The Netherlands have low levels of resistance to antibiotics. This report describes what is believed to be the first carbapenem-resistant Klebsiella pneumoniae producing an OXA-48 type β-lactamase in The Netherlands. The isolate co-produced a CTX-M-15 type β-lactamase and was recovered from a patient who was transferred from a hospital in India to an intensive care unit in The Netherlands. His recovery in The Netherlands was complicated by pneumonia due to the carbapenem-resistant K. pneumoniae to which he eventually succumbed. Pre-emptive screening for carbapenem-resistant Enterobacteriaceae in selected patients could be imperative to maintain the low prevalence of these highly resistant bacteria in Dutch hospitals.
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Affiliation(s)
- Jayant S Kalpoe
- Department of Medical Microbiology and Infection Prevention, Saint Lucas Andreas Hospital, Amsterdam, The Netherlands
| | - Nashwan Al Naiemi
- Microbiology Laboratory Twente Achterhoek, Enschede, The Netherlands
| | - Laurent Poirel
- Service de Bactériologie-Virologie-Hygiène, Hôpital de Bicêtre, Le Kremlin-Bicêtre, France
| | - Patrice Nordmann
- Service de Bactériologie-Virologie-Hygiène, Hôpital de Bicêtre, Le Kremlin-Bicêtre, France
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123
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Lee K. Trend of Bacterial Resistance for the Past 50 Years in Korea and Future Perspectives - Gram-negative Bacteria. Infect Chemother 2011. [DOI: 10.3947/ic.2011.43.6.458] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Affiliation(s)
- Kyungwon Lee
- Department of Laboratory Medicine, Yonsei University College of Medicine, Seoul, Korea
- Research Institute of Bacterial Resistance, Yonsei University College of Medicine, Seoul, Korea
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124
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Chia JH, Su LH, Lee MH, Kuo AJ, Shih NY, Siu LK, Wu TL. Development of High-Level Carbapenem Resistance inKlebsiella pneumoniaeAmong Patients with Prolonged Hospitalization and Carbapenem Exposure. Microb Drug Resist 2010; 16:317-25. [DOI: 10.1089/mdr.2009.0048] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Ju-Hsin Chia
- Department of Laboratory Medicine, Chang Gung Memorial Hospital, Taoyuan, Taiwan
- Department of Medical Biotechnology and Laboratory Science, Chang Gung University, Taoyuan, Taiwan
| | - Lin-Hui Su
- Department of Laboratory Medicine, Chang Gung Memorial Hospital, Taoyuan, Taiwan
- Department of Medical Biotechnology and Laboratory Science, Chang Gung University, Taoyuan, Taiwan
| | - Ming-Hsun Lee
- Division of Infectious Diseases, Chang Gung Memorial Hospital, Taoyuan, Taiwan
| | - An-Jing Kuo
- Department of Laboratory Medicine, Chang Gung Memorial Hospital, Taoyuan, Taiwan
- Department of Medical Biotechnology and Laboratory Science, Chang Gung University, Taoyuan, Taiwan
| | - Neng-Yao Shih
- Cancer Institute, National Health Research Institutes, Taipei, Taiwan
| | - Leung Kei Siu
- Department of Medical Biotechnology and Laboratory Science, Chang Gung University, Taoyuan, Taiwan
- Unit of Infectious Diseases, Division of Clinical Research, National Health Research Institutes, Taipei, Taiwan
| | - Tsu-Lan Wu
- Department of Laboratory Medicine, Chang Gung Memorial Hospital, Taoyuan, Taiwan
- Department of Medical Biotechnology and Laboratory Science, Chang Gung University, Taoyuan, Taiwan
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125
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Bebrone C, Lassaux P, Vercheval L, Sohier JS, Jehaes A, Sauvage E, Galleni M. Current challenges in antimicrobial chemotherapy: focus on ß-lactamase inhibition. Drugs 2010; 70:651-79. [PMID: 20394454 DOI: 10.2165/11318430-000000000-00000] [Citation(s) in RCA: 119] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The use of the three classical beta-lactamase inhibitors (clavulanic acid, tazobactam and sulbactam) in combination with beta-lactam antibacterials is currently the most successful strategy to combat beta-lactamase-mediated resistance. However, these inhibitors are efficient in inactivating only class A beta-lactamases and the efficiency of the inhibitor/antibacterial combination can be compromised by several mechanisms, such as the production of naturally resistant class B or class D enzymes, the hyperproduction of AmpC or even the production of evolved inhibitor-resistant class A enzymes. Thus, there is an urgent need for the development of novel inhibitors. For serine active enzymes (classes A, C and D), derivatives of the beta-lactam ring such as 6-beta-halogenopenicillanates, beta-lactam sulfones, penems and oxapenems, monobactams or trinems seem to be potential starting points to design efficient molecules (such as AM-112 and LK-157). Moreover, a promising non-beta-lactam molecule, NXL-104, is now under clinical development. In contrast, an ideal inhibitor of metallo-beta-lactamases (class B) remains to be found, despite the huge number of potential molecules already described (biphenyl tetrazoles, cysteinyl peptides, mercaptocarboxylates, succinic acid derivatives, etc.). The search for such an inhibitor is complicated by the absence of a covalent intermediate in their catalytic mechanisms and the fact that beta-lactam derivatives often behave as substrates rather than as inhibitors. Currently, the most promising broad-spectrum inhibitors of class B enzymes are molecules presenting chelating groups (thiols, carboxylates, etc.) combined with an aromatic group. This review describes all the types of molecules already tested as potential beta-lactamase inhibitors and thus constitutes an update of the current status in beta-lactamase inhibitor discovery.
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Affiliation(s)
- Carine Bebrone
- Biological Macromolecules, Centre for Protein Engineering, University of Liège, Liège, Belgium.
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126
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Outbreak of meropenem-resistant Serratia marcescens comediated by chromosomal AmpC beta-lactamase overproduction and outer membrane protein loss. Antimicrob Agents Chemother 2010; 54:5057-61. [PMID: 20876374 DOI: 10.1128/aac.00768-10] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The aim of this study was to investigate the mechanisms involved in the meropenem resistance of Serratia marcescens clinical isolates. Meropenem-resistant (MIC range, 16 to 32 μg/ml) S. marcescens isolates were recovered from nine patients in a tertiary hospital in Seoul, South Korea, from June to November 2005. All the isolates shared identical or similar (>85% similarity) SpeI macrorestriction patterns, indicating clonal spread. PCR experiments did not detect any carbapenemase in those isolates. They carried the bla(CTX-M-22) gene located on a 150-kbp plasmid of the incompatibility group L/M; however, the addition of clavulanic acid exhibited few effects on meropenem MICs. Although meropenem MICs were reduced 4- to 16-fold with the addition of boronic acid, no plasmid-borne AmpC β-lactamase gene was detected in PCR experiments. Real-time quantitative PCR experiments showed that expression levels of the chromosomal ampC gene in those isolates were 87.06 to 155.76 times higher than that of the reference strain ATCC 8100. SDS-PAGE showed a lack of the 42-kDa outer membrane protein (OmpF). In combination with the overproduction of the chromosomal AmpC enzyme, the loss of OmpF may have played a role in the acquisition of meropenem resistance in our isolates.
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127
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Jetter M, Spaniol V, Troller R, Aebi C. Down-regulation of porin M35 in Moraxella catarrhalis by aminopenicillins and environmental factors and its potential contribution to the mechanism of resistance to aminopenicillins. J Antimicrob Chemother 2010; 65:2089-96. [PMID: 20801781 PMCID: PMC2941675 DOI: 10.1093/jac/dkq312] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Objectives The outer membrane protein M35 of Moraxella catarrhalis is an antigenically conserved porin. Knocking out M35 significantly increases the MICs of aminopenicillins. The aim of this study was to determine the biological mechanism of this potentially new antimicrobial resistance mechanism of M. catarrhalis and the behaviour of M35 in general stress situations. Methods PCR using m35-specific primers was used to detect the m35 gene in clinical isolates. The m35 mRNA expression of strains 300, O35E and 415 after exposure to amoxicillin and different stress conditions was measured by real-time PCR and normalized in relation to their 16S rRNA expression. The expression of M35 protein was analysed by SDS-PAGE and western blotting. Results Screening of 52 middle ear isolates resulted in positive PCR products for all tested strains. The analysis of m35 mRNA expression after amoxicillin treatment showed 24%–85% down-regulation compared with the respective amoxicillin-free controls in all three strains tested. Also, analysis of protein concentrations revealed lower M35 expression after growth with amoxicillin. Investigation of M35 during general stress responses showed down-regulation of the porin with growth at 26°C and 42°C, under hyperosmolar stress and under iron restriction. Conclusions The reduced expression of M35 after aminopenicillin exposure indicates a novel resistance mechanism against aminopenicillins in M. catarrhalis, which may be relevant in vivo. The differences in expression after different stress treatments demonstrate that M35 is involved in general stress responses.
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Affiliation(s)
- Marion Jetter
- Institute for Infectious Diseases, University of Bern, CH-3010 Bern, Switzerland
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128
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Phenotypic and biochemical comparison of the carbapenem-hydrolyzing activities of five plasmid-borne AmpC β-lactamases. Antimicrob Agents Chemother 2010; 54:4556-60. [PMID: 20733047 DOI: 10.1128/aac.01762-09] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The CMY-2, ACT-1, DHA-1, ACC-1, and FOX-1 enzymes are representative of five plasmid-mediated AmpC (pAmpC) β-lactamase clusters. Resistance to imipenem has been reported in Enterobacteriaceae as a result of pAmpC expression combined with decreased outer membrane permeability. The aim of this study was to determine the role of different pAmpCs in carbapenem resistance and to define the structure/activity relationship supporting carbapenemase activity. The ampC genes encoding the five pAmpCs and the chromosomal AmpC of Escherichia coli EC6, which was used as a reference cephalosporinase, were cloned and introduced into wild-type E. coli TOP10 and OmpC/OmpF porin-deficient E. coli HB4 strains. The MICs of β-lactams for the recombinant strains revealed that CMY-2, ACT-1, and DHA-1 β-lactamases conferred a high level of resistance to ceftazidime and cefotaxime once expressed in E. coli TOP10 and reduced significantly the susceptibility to imipenem once expressed in E. coli HB4. In contrast, FOX-1 and ACC-1 enzymes did not confer resistance to imipenem. Biochemical analysis showed that CMY-2 β-lactamase and, to a lesser extent, ACT-1 exhibited the highest catalytic efficiency toward imipenem and showed low K(m) values. A modeling study revealed that the large R2 binding site of these two enzymes may support the carbapenemase activity. Therefore, CMY-2-type, ACT-1-type, and DHA-1-type β-lactamases may promote the emergence of carbapenem resistance in porin-deficient clinical isolates.
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129
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Genetic factors associated with elevated carbapenem resistance in KPC-producing Klebsiella pneumoniae. Antimicrob Agents Chemother 2010; 54:4201-7. [PMID: 20660684 DOI: 10.1128/aac.00008-10] [Citation(s) in RCA: 119] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In the United States, the most prevalent mechanism of carbapenem resistance among Enterobacteriaceae is the production of a Klebsiella pneumoniae carbapenemase (KPC). KPC-producing isolates often exhibit a range of carbapenem MICs. To better understand the factors that contribute to overall carbapenem resistance, we analyzed 27 KPC-producing K. pneumoniae isolates with different levels of carbapenem resistance, 11 with low-level (i.e., meropenem or imipenem MIC ≤ 4 μg/ml), 2 with intermediate-level (i.e., meropenem and imipenem MIC = 8 μg/ml), and 14 with high-level (i.e., imipenem or meropenem MIC ≥ 16 μg/ml) carbapenem resistance, that were received from throughout the United States. Among 14 isolates that exhibited high-level carbapenem resistance, Western blot analysis indicated that 10 produced an elevated amount of KPC. These isolates either contained an increased bla(KPC) gene copy number (n = 3) or had deletions directly upstream of the bla(KPC) gene (n = 7). Four additional isolates lacked elevated KPC production but had high-level carbapenem resistance. Porin sequencing analysis identified 22 isolates potentially lacking a functional OmpK35 and three isolates potentially lacking a functional OmpK36. The highest carbapenem MICs were found in two isolates that lacked both functioning porins and produced elevated amounts of KPC. The 11 isolates with low-level carbapenem resistance contained neither an upstream deletion nor increased bla(KPC) copy number. These results suggest that both bla(KPC) copy number and deletions in the upstream genetic environment affect the level of KPC production and may contribute to high-level carbapenem resistance in KPC-producing K. pneumoniae, particularly when coupled with OmpK36 porin loss.
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130
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[Interpretive reading of enterobacteria antibiograms]. Enferm Infecc Microbiol Clin 2010; 28:638-45. [PMID: 20579780 DOI: 10.1016/j.eimc.2010.05.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2010] [Accepted: 05/05/2010] [Indexed: 11/23/2022]
Abstract
The resistance pattern observed in the antibiogram of an isolate should be the sum of its natural resistance pattern, characteristic of the species, plus the acquired resistances. In Enterobacteriaceae, the production of inactivating enzymes is the main mechanism of resistance to beta-lactams and aminoglycosides. Each one of these enzymes recognizes one or more specific beta-lactams or aminoglycosides as substrate. This substrate specificity implies a specific resistance pattern from which we can deduce the enzymes present in the isolate. However, enzymatic-mediated resistance is not the only mechanism implicated and resistance is frequently multifactorial. Resistance to quinolones is mainly due to precise, sequential chromosomal mutations that can be selected by fluoroquinolone treatments. Recently, certain plasmid-mediated genes which code enzymes that modify quinolones or that are target protectors have been implicated in the low level resistance to quinolones.
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131
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Identification of CTX-M beta-lactamases in Escherichia coli from hospitalized patients and residents of long-term care facilities. Diagn Microbiol Infect Dis 2010; 66:402-6. [PMID: 20226330 DOI: 10.1016/j.diagmicrobio.2009.11.012] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2009] [Revised: 10/28/2009] [Accepted: 11/20/2009] [Indexed: 11/21/2022]
Abstract
Bacteria harboring CTX-M extended-spectrum beta-lactamases (ESBLs) have been identified worldwide, with most reports coming from regions outside North America. We have identified CTX-M enzymes in 31% of ESBL-positive Escherichia coli isolates from our hospital and more than half (53%) of the isolates from associated long-term care facilities. Approximately 3/4 of all CTX-M-bearing isolates were from urine specimens, with a predominance of CTX-M-15. A large proportion of such isolates were nonsusceptible to levofloxacin, trimethoprim/sulfamethoxazole, and all beta-lactam antimicrobials with the exception of the carbapenems, requiring carbapenem therapy for acute urinary tract infection or urinary tract-related sepsis. CTX-M beta-lactamases have emerged within our location, and detection of bacteria harboring these enzymes in the clinical microbiology laboratory remains problematic because molecular methods are needed for their identification.
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132
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Wu Q, Liu Q, Han L, Sun J, Ni Y. Plasmid-mediated carbapenem-hydrolyzing enzyme KPC-2 and ArmA 16S rRNA methylase conferring high-level aminoglycoside resistance in carbapenem-resistant Enterobacter cloacae in China. Diagn Microbiol Infect Dis 2010; 66:326-8. [DOI: 10.1016/j.diagmicrobio.2009.10.003] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2009] [Revised: 09/12/2009] [Accepted: 10/04/2009] [Indexed: 10/20/2022]
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133
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Pitout J, Le P, Moore K, Church D, Gregson D. Detection of AmpC β-lactamases in Escherichia coli, Klebsiella spp., Salmonella spp. and Proteus mirabilis in a regional clinical microbiology laboratory. Clin Microbiol Infect 2010; 16:165-70. [DOI: 10.1111/j.1469-0691.2009.02756.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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134
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Rhomberg PR, Jones RN. Summary trends for the Meropenem Yearly Susceptibility Test Information Collection Program: a 10-year experience in the United States (1999-2008). Diagn Microbiol Infect Dis 2010; 65:414-26. [PMID: 19833471 DOI: 10.1016/j.diagmicrobio.2009.08.020] [Citation(s) in RCA: 133] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2009] [Accepted: 08/28/2009] [Indexed: 10/20/2022]
Abstract
The Meropenem Yearly Susceptibility Test Information Collection (MYSTIC) Program was a global, longitudinal antimicrobial resistance surveillance network of more than 100 medical centers worldwide monitoring the susceptibility of meropenem and selected other broad-spectrum comparator agents. In 1999, and from 2000 through 2008, a total of 10 or 15 United States (USA) medical centers each forwarded 200 nonduplicate clinical isolates from serious infections to a central processing laboratory. Over the 10-year period of this surveillance program, the activity of meropenem and an average of 11 other antimicrobial agents were assessed against a total of 27 289 bacterial isolates using Clinical and Laboratory Standards Institute reference methods. Meropenem consistently demonstrated low resistance rates against Enterobacteriaceae species isolates through 2008 and did not exhibit a widespread change in resistance rates over the monitored interval. In fact, the incidence of emerging carbapenemase-producing (KPC-type) Klebsiella spp. showed a decline in 2008 compared to the steeply increasing rates observed from 2004 to 2007. Moreover, the KPC serine carbapenemases have spread to other Enterobacteriaceae species monitored by the MYSTIC Program. Greatest increases in antimicrobial resistance rates were observed for the fluoroquinolones (ciprofloxacin, levofloxacin) among all species monitored by the MYSTIC Program. Current susceptibility rates for meropenem when tested against prevalent pathogens were Pseudomonas aeruginosa (439 strains, 85.4% susceptible), Enterobacteriaceae (1537 strains, 97.3% susceptible), methicillin-susceptible staphylococci (460 strains, 100.0% susceptible), Streptococcus pneumoniae (125 strains, 80.2% at meningitis susceptibility breakpoints), other streptococci (159 strains, 90.0-100.0% susceptible), and Acinetobacter spp. (127 strains, 45.7% susceptible), the widest spectrum among beta-lactams tested in 2008 and throughout the last decade. Continued local surveillance of broad-spectrum agents following the completion of the MYSTIC Program (USA) appears critical to detect emerging resistances among pathogens causing the most serious infections requiring carbapenem agents.
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135
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Ushida K, Segawa T, Kohshima S, Takeuchi N, Fukui K, Li Z, Kanda H. Application of real-time PCR array to the multiple detection of antibiotic resistant genes in glacier ice samples. J GEN APPL MICROBIOL 2010; 56:43-52. [DOI: 10.2323/jgam.56.43] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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136
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137
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Actividad comparativa del ertapenem frente a Klebsiella pneumoniae productor de betalactamasas de espectro extendido o betalactamasas de AmpC plasmídicas: efecto inóculo y papel de la pérdida de porinas. Enferm Infecc Microbiol Clin 2010; 28:27-30. [DOI: 10.1016/j.eimc.2009.03.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2008] [Revised: 03/12/2009] [Accepted: 03/16/2009] [Indexed: 11/17/2022]
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138
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Abstract
Two classification schemes for beta-lactamases are currently in use. The molecular classification is based on the amino acid sequence and divides beta-lactamases into class A, C, and D enzymes which utilize serine for beta-lactam hydrolysis and class B metalloenzymes which require divalent zinc ions for substrate hydrolysis. The functional classification scheme updated herein is based on the 1995 proposal by Bush et al. (K. Bush, G. A. Jacoby, and A. A. Medeiros, Antimicrob. Agents Chemother. 39:1211-1233, 1995). It takes into account substrate and inhibitor profiles in an attempt to group the enzymes in ways that can be correlated with their phenotype in clinical isolates. Major groupings generally correlate with the more broadly based molecular classification. The updated system includes group 1 (class C) cephalosporinases; group 2 (classes A and D) broad-spectrum, inhibitor-resistant, and extended-spectrum beta-lactamases and serine carbapenemases; and group 3 metallo-beta-lactamases. Several new subgroups of each of the major groups are described, based on specific attributes of individual enzymes. A list of attributes is also suggested for the description of a new beta-lactamase, including the requisite microbiological properties, substrate and inhibitor profiles, and molecular sequence data that provide an adequate characterization for a new beta-lactam-hydrolyzing enzyme.
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139
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Balcewich MD, Stubbs KA, He Y, James TW, Davies GJ, Vocadlo DJ, Mark BL. Insight into a strategy for attenuating AmpC-mediated beta-lactam resistance: structural basis for selective inhibition of the glycoside hydrolase NagZ. Protein Sci 2009; 18:1541-51. [PMID: 19499593 DOI: 10.1002/pro.137] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
NagZ is an exo-N-acetyl-beta-glucosaminidase, found within Gram-negative bacteria, that acts in the peptidoglycan recycling pathway to cleave N-acetylglucosamine residues off peptidoglycan fragments. This activity is required for resistance to cephalosporins mediated by inducible AmpC beta-lactamase. NagZ uses a catalytic mechanism involving a covalent glycosyl enzyme intermediate, unlike that of the human exo-N-acetyl-beta-glucosaminidases: O-GlcNAcase and the beta-hexosaminidase isoenzymes. These latter enzymes, which remove GlcNAc from glycoconjugates, use a neighboring-group catalytic mechanism that proceeds through an oxazoline intermediate. Exploiting these mechanistic differences we previously developed 2-N-acyl derivatives of O-(2-acetamido-2-deoxy-D-glucopyranosylidene)amino-N-phenylcarbamate (PUGNAc), which selectively inhibits NagZ over the functionally related human enzymes and attenuate antibiotic resistance in Gram-negatives that harbor inducible AmpC. To understand the structural basis for the selectivity of these inhibitors for NagZ, we have determined its crystallographic structure in complex with N-valeryl-PUGNAc, the most selective known inhibitor of NagZ over both the human beta-hexosaminidases and O-GlcNAcase. The selectivity stems from the five-carbon acyl chain of N-valeryl-PUGNAc, which we found ordered within the enzyme active site. In contrast, a structure determination of a human O-GlcNAcase homologue bound to a related inhibitor N-butyryl-PUGNAc, which bears a four-carbon chain and is selective for both NagZ and O-GlcNAcase over the human beta-hexosamnidases, reveals that this inhibitor induces several conformational changes in the active site of this O-GlcNAcase homologue. A comparison of these complexes, and with the human beta-hexosaminidases, reveals how selectivity for NagZ can be engineered by altering the 2-N-acyl substituent of PUGNAc to develop inhibitors that repress AmpC mediated beta-lactam resistance.
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Affiliation(s)
- Misty D Balcewich
- Department of Microbiology, University of Manitoba, Winnipeg, Manitoba, Canada
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140
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Wang XD, Cai JC, Zhou HW, Zhang R, Chen GX. Reduced susceptibility to carbapenems in Klebsiella pneumoniae clinical isolates associated with plasmid-mediated β-lactamase production and OmpK36 porin deficiency. J Med Microbiol 2009; 58:1196-1202. [PMID: 19528170 DOI: 10.1099/jmm.0.008094-0] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Two carbapenem-non-susceptible Klebsiella pneumoniae isolates, Z2554 and Z2110, were collected from a hospital in China and analysed by PFGE. K. pneumoniae Z2554 and Z2110 were genetically unrelated and showed resistance to ertapenem, and reduced susceptibility to imipenem and meropenem. Analysis of their β-lactamases indicated that K. pneumoniae Z2554 produced TEM-1 and CTX-M-14 β-lactamases, whilst Z2110 produced a plasmid-mediated AmpC β-lactamase, DHA-1, in addition to TEM-1 and CTX-M-14. SDS-PAGE analysis of the outer-membrane proteins (OMPs) revealed that both isolates lacked an OMP of ∼39 kDa (OmpK36), whilst Z2110 had an additional protein with an approximate molecular mass of 26 kDa. Analysis of the OMP-encoding genes demonstrated that the ompK35 sequence of K. pneumoniae Z2554 and Z2110 contained a number of silent mutations. In ompK36, several insertions and deletions of short DNA fragments (1–6 bp) were detected in both isolates. The N-terminal sequence of the ∼26 kDa protein band identified in Z2110 had no similarity to the sequence of OmpK36. Instead, it shared high similarity with hypothetical protein KPN_03267 originating from K. pneumoniae subsp. pneumoniae MGH 78578. It was concluded that β-lactamase production combined with OmpK36 deficiency results in ertapenem resistance, and reduced imipenem and meropenem susceptibility, in K. pneumoniae Z2554 and Z2110. OmpK36 may play an important role in the resistance or reduced susceptibility to carbapenems in K. pneumoniae producing AmpC, extended-spectrum β-lactamase or broad-spectrum β-lactamase.
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Affiliation(s)
- Xuan Ding Wang
- 2nd Affiliated Hospital of Zhejiang University, Zhejiang University, 88 Jiefang Road, Hangzhou 310009, PR China
| | - Jia Chang Cai
- 2nd Affiliated Hospital of Zhejiang University, Zhejiang University, 88 Jiefang Road, Hangzhou 310009, PR China
| | - Hong Wei Zhou
- 2nd Affiliated Hospital of Zhejiang University, Zhejiang University, 88 Jiefang Road, Hangzhou 310009, PR China
| | - Rong Zhang
- 2nd Affiliated Hospital of Zhejiang University, Zhejiang University, 88 Jiefang Road, Hangzhou 310009, PR China
| | - Gong-Xiang Chen
- 2nd Affiliated Hospital of Zhejiang University, Zhejiang University, 88 Jiefang Road, Hangzhou 310009, PR China
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141
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Jiang X, Espedido BA, Partridge SR, Thomas LC, Wang F, Iredell JR. Paradoxical effect of Klebsiella pneumoniae OmpK36 porin deficiency. Pathology 2009; 41:388-92. [PMID: 19404854 DOI: 10.1080/00313020902908854] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
AIM To evaluate the effect of defined mutations in the major OmpK35 and OmpK36 porins in Klebsiella pneumoniae on the activity of two common plasmid-mediated AmpC enzymes. METHODS Naturally occurring conjugative plasmids containing bla(DHA-1) and bla(CMY-2) were obtained from K. pneumoniae isolates in western Sydney. These were moved into K. pneumoniae ATCC13883 and isogenic porin knockouts Kp885 (DeltaompK35) and Kp886 (DeltaompK36), created by homologous recombination of kanamycin resistance cartridges into the specified genes, and their antimicrobial susceptibilities compared. RESULTS beta-lactam resistance was greater in the presence of CMY-2-containing plasmids than DHA-1-containing plasmids, and higher in K. pneumoniae than Escherichia coli. Neither cefepime nor imipenem resistance was observed, and DHA-mediated cefotaxime and ticarcillin/clavulanate resistance was unexpectedly reduced from 8-24 (CTX) and >256 (TIM) mg/L in Kp13883 to 1-2 (CTX) and 32-48 mg/L (TIM) in the isogenic DeltaompK36 porin knockout Kp886. CONCLUSIONS AmpC plasmids in particular are an important cause of transmissible resistance to ticarcillin/clavulanate in K. pneumoniae, but probably not in E. coli. Single knockouts of OmpK35 and OmpK36 porins in K. pneumoniae do not significantly increase antibiotic resistance in K. pneumoniae, and a paradoxical lowering of resistance to CTX and TIM is seen with deletion of ompK36. This has potentially important clinical implications.
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Affiliation(s)
- Xiuhong Jiang
- Centre for Infectious Diseases and Microbiology, University of Sydney, Westmead Hospital, Sydney, NSW, Australia
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142
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Evaluation of PCR-based testing for surveillance of KPC-producing carbapenem-resistant members of the Enterobacteriaceae family. J Clin Microbiol 2009; 47:3261-5. [PMID: 19675211 DOI: 10.1128/jcm.02368-08] [Citation(s) in RCA: 99] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The spread of carbapenem-resistant members of the Enterobacteriaceae family (CRE) harboring carbapenemases is an emerging public health threat. As KPC-producing Klebsiella species are endemic in our tertiary care hospital, we aimed to evaluate a PCR-based surveillance test for identification of rectal carriage of KPC-producing CRE. We conducted a surveillance study between May and December 2007. Rectal swabs were collected from patients known to harbor CRE and from contacts of newly discovered patients harboring CRE. Specimens were evaluated by culture and by PCR analysis for blaKPC and were defined as positive if CRE was cultured and blaKPC was identified. Discrepant results between the culture and PCR analysis were resolved by subculturing, repeating the PCR, and performing a hydrolysis assay. Positive CRE cultures prior or subsequent to the time of sampling for the study were also taken into consideration. Sensitivity, specificity, and time to result were calculated. A total of 755 swabs were included. Concordant results were documented for 735 specimens; 51 were positive as determined by both PCR and culture. Discrepancies existed for 20 swabs; 9 were blaKPC negative and CRE culture positive, and 11 were blaKPC positive and CRE culture negative. After repeat testing, a total of 64 samples were classified as blaKPC-positive CRE. The sensitivity and specificity of the PCR analysis were 92.2% and 99.6%, respectively, and those of the culture were 87.5% and 99.4%, respectively. Over the last 3 months of the study, the sensitivity of the PCR improved to 96.3%, versus 77.8% for culture. Time to result was 30 h for the PCR and 60 h (negative) and 75 h (positive) for the CRE culture. blaKPC PCR-based testing is a useful method for the surveillance of KPC-producing CRE. Its main advantage over culturing is a shorter time to result, and it may prove to be more sensitive.
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143
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Yamada Y, Ishii Y, Kouyama Y, Katho M, Odashiro R, Yamahata K, Tateda K, Yamaguchi K, Suwabe A. Characterization of Klebsiella pneumoniae producing SHV-12 and DHA-1 beta-lactamases accompanied by carbapenem resistance during hospitalization in a chronic care ward in Japan. J Chemother 2009; 21:445-7. [PMID: 19622465 DOI: 10.1179/joc.2009.21.4.445] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Affiliation(s)
- Y Yamada
- Department of Laboratory Medicine, Iwate Medical University School of Medicine, Morioka, Japan.
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144
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Gröbner S, Linke D, Schütz W, Fladerer C, Madlung J, Autenrieth IB, Witte W, Pfeifer Y. Emergence of carbapenem-non-susceptible extended-spectrum β-lactamase-producing Klebsiella pneumoniae isolates at the university hospital of Tübingen, Germany. J Med Microbiol 2009; 58:912-922. [DOI: 10.1099/jmm.0.005850-0] [Citation(s) in RCA: 140] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The spread of Gram-negative bacteria with plasmid-borne extended-spectrum β-lactamases (ESBLs) has become a worldwide problem. This study analysed a total of 366 ESBL-producing Enterobacteriaceae strains isolated from non-selected patient specimens at the university hospital of Tübingen in the period January 2003 to December 2007. Although the overall ESBL rate was comparatively low (1.6 %), the percentages of ESBL-producing Enterobacter spp. and Escherichia coli increased from 0.8 and 0.5 %, respectively, in 2003 to 4.6 and 3.8 % in 2007. In particular, the emergence was observed of one carbapenem-resistant ESBL-producing E. coli isolate and five carbapenem-non-susceptible ESBL-positive Klebsiella pneumoniae isolates, in two of which carbapenem resistance development was documented in vivo under a meropenem-containing antibiotic regime. The possible underlying mechanism for this carbapenem resistance in three of the K. pneumoniae isolates was loss of the Klebsiella porin channel protein OmpK36 as shown by PCR analysis. The remaining two K. pneumoniae isolates exhibited increased expression of a tripartite AcrAB–TolC efflux pump as demonstrated by SDS-PAGE and mass spectrometry analysis of bacterial outer-membrane extracts, which, in addition to other unknown mechanisms, may contribute towards increasing the carbapenem MIC values further. Carbapenem-non-susceptible ESBL isolates may pose a new problem in the future due to possible outbreak situations and limited antibiotic treatment options. Therefore, a systematic exploration of intestinal colonization with ESBL isolates should be reconsidered, at least for haemato-oncological departments from where four of the five carbapenem-non-susceptible ESBL isolates originated.
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Affiliation(s)
- Sabine Gröbner
- Institute of Medical Microbiology and Hygiene, Eberhard Karls University of Tübingen, Elfriede-Aulhorn-Str. 6, D-72076 Tübingen, Germany
| | - Dirk Linke
- Max Planck Institute for Developmental Biology, Department I, Protein Evolution, Spemannstr. 35, D-72076 Tübingen, Germany
| | - Wolfgang Schütz
- Proteome Centre Tübingen, Interfaculty Institute of Cell Biology, University of Tübingen, Auf der Morgenstelle 15, D-72076 Tübingen, Germany
| | - Claudia Fladerer
- Proteome Centre Tübingen, Interfaculty Institute of Cell Biology, University of Tübingen, Auf der Morgenstelle 15, D-72076 Tübingen, Germany
| | - Johannes Madlung
- Proteome Centre Tübingen, Interfaculty Institute of Cell Biology, University of Tübingen, Auf der Morgenstelle 15, D-72076 Tübingen, Germany
| | - Ingo B. Autenrieth
- Institute of Medical Microbiology and Hygiene, Eberhard Karls University of Tübingen, Elfriede-Aulhorn-Str. 6, D-72076 Tübingen, Germany
| | - Wolfgang Witte
- Robert Koch Institute, Burgstr. 37, D-38855 Wernigerode, Germany
| | - Yvonne Pfeifer
- Robert Koch Institute, Burgstr. 37, D-38855 Wernigerode, Germany
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Landman D, Bratu S, Quale J. Contribution of OmpK36 to carbapenem susceptibility in KPC-producing Klebsiella pneumoniae. J Med Microbiol 2009; 58:1303-1308. [PMID: 19556371 DOI: 10.1099/jmm.0.012575-0] [Citation(s) in RCA: 103] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Isolates of Klebsiella pneumoniae harbouring the carbapenemase KPC may have carbapenem MICs that remain in the susceptible range, and may therefore go unrecognized. To understand the mechanisms contributing to the variability in carbapenem MICs, 20 clinical isolates, all belonging to either of two clonal groups of KPC-possessing K. pneumoniae endemic to New York City, were examined. Expression of genes encoding KPC, the porins OmpK35 and OmpK36, and the efflux pump AcrAB was examined by real-time RT-PCR. Outer-membrane profiles of selected KPC-producing isolates were examined by SDS-PAGE, and proteins were identified by matrix-assisted laser desorption/ionization mass spectrometry. The identification of SHV and TEM beta-lactamases and the genomic sequences of ompK35 and ompK36 were determined by PCR and DNA sequencing, respectively. For one clonal group, carbapenem MICs increased with decreasing expression of ompK36. A second clonal group also had carbapenem MICs that correlated with ompK36 expression. However, all of the isolates in this latter group continued to produce OmpK36, suggesting that porin configuration may affect entry of carbapenems. For isolates that had the greatest expression of ompK36, carbapenem MICs tended to be lower when determined by the broth microdilution technique, and scattered colonies were seen around the Etest zones of inhibition. All of the KPC-producing isolates were highly resistant to ertapenem, regardless of ompK36 expression. In conclusion, isolates of KPC-possessing K. pneumoniae that express ompK36 tend to have lower MICs to carbapenems and therefore may be more difficult to detect by clinical laboratories. Regardless of ompK36 expression, all of the KPC producers were consistently resistant to ertapenem.
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Affiliation(s)
- David Landman
- State University of New York Downstate Medical Center, Brooklyn, NY, USA
| | - Simona Bratu
- State University of New York Downstate Medical Center, Brooklyn, NY, USA
| | - John Quale
- State University of New York Downstate Medical Center, Brooklyn, NY, USA
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147
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Nordmann P, Cuzon G, Naas T. The real threat of Klebsiella pneumoniae carbapenemase-producing bacteria. THE LANCET. INFECTIOUS DISEASES 2009; 9:228-36. [PMID: 19324295 DOI: 10.1016/s1473-3099(09)70054-4] [Citation(s) in RCA: 1090] [Impact Index Per Article: 72.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
From early this decade, Enterobacteriaceae that produce Klebsiella pneumoniae carbapenemases (KPC) were reported in the USA and subsequently worldwide. These KPC-producing bacteria are predominantly involved in nosocomial and systemic infections; although they are mostly Enterobacteriaceae, they can also be, rarely, Pseudomonas aeruginosa isolates. KPC beta lactamases (KPC-1 to KPC-7) confer decreased susceptibility or resistance to virtually all beta lactams. Carbapenems (imipenem, meropenem, and ertapenem) may thus become inefficient for treating enterobacterial infections with KPC-producing bacteria, which are, in addition, resistant to many other non-beta-lactam molecules, leaving few available therapeutic options. Detection of KPC-producing bacteria may be difficult based on routine antibiotic susceptibility testing. It is therefore crucial to implement efficient infection control measures to limit the spread of these pathogens.
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Affiliation(s)
- Patrice Nordmann
- Service de Bactériologie-Virologie-Hygiène, INSERM U914 "Emerging Resistance to Antibiotics", Hôpital de Bicêtre, Assistance Publique/Hôpitaux de Paris, Faculté de Médecine and Université Paris Sud, K -Bicêtre, France
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148
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Ahmed SH, Daef EA, Badary MS, Mahmoud MA, Abd-Elsayed AA. Nosocomial blood stream infection in intensive care units at Assiut University Hospitals (Upper Egypt) with special reference to extended spectrum beta-lactamase producing organisms. BMC Res Notes 2009; 2:76. [PMID: 19419535 PMCID: PMC2694819 DOI: 10.1186/1756-0500-2-76] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2008] [Accepted: 05/06/2009] [Indexed: 11/10/2022] Open
Abstract
Aim This study investigated the nosocomial blood stream infection (BSI) in the adult ICUs in Assiut university hospitals to evaluate the rate of infection in different ICUs, causative microorganisms, antimicrobial resistance, outcome of infection, risk factors, prevalence of extended spectrum B-lactamase producing organisms and molecular typing of Klebsiella pneumoniae strains to highlight the role of environment as a potential source of nosocomial BSI. Methods This study was conducted over a period of 12 months from January 2006 to December 2006. All Patients admitted to the different adult ICUs were monitored daily by attending physicians for subsequent development of nosocomial BSI. Blood cultures were collected from suspected patients to detect the causative organisms. After antimicrobial susceptibility testing, detection of ESBLs was conducted among gram negative isolates. Klebsiella pneumoniae isolates were tested by PCR to determine the most common group of B-lactamase genes responsible for resistance. Klebsiella pneumoniae isolates from infected patients and those isolated from the environment were typed by RAPD technique to investigate the role of environment in transmission of infection. Results The study included 2095 patients who were admitted to different ICUs at Assiut University Hospitals from January 2006 to December 2006. Blood samples were collected from infected patients for blood cultures. The colonies were identified and antibiotic sensitivities were performed. This study showed that the rate of nosocomial BSI was 75 per 1000 ICU admissions with the highest percentages in Trauma ICU (17%). Out of 159 patients with primary bloodstream infection, 61 patients died representing a crude mortality rate of 38%. Analysis of the organisms causing BSI showed that Gram positive organisms were reported in 69.1% (n = 121); MRSA was the most prevalent (18.9%), followed by methicillin resistant coagulase negative Staphylococci (16%). Gram negative bacilli were reported in 29.1% (n = 51). In this case, Klebsiella pneumoniae was the most common (10.3%) followed E coli (8.6%). Candida spp. was reported only in (1.7%) of isolates. Antibiotics sensitivities of Gram positive organisms showed that these organisms were mostly sensitive to vancomycin (90.1%), while Gram negative organisms were mostly sensitive to imipenem (90.2%). In this study we tested Gram negative isolates for the production of the ESBL enzyme and concluded that 64.7% (33/51) of patients' isolates and 20/135 (14.8%) environmental isolates were confirmed to be ESBL producers. The type of β-lactamase gene was determined by polymerase chain reaction which showed that SHV was the main type. Molecular typing was done for 18 Klebsiella pneumoniae strains that caused nosocomial BSI and for the 36 Klebsiella pneumoniae strains which were isolated from the environmental samples by the RAPD method. The two environmental strains were identical, with one isolated from a patient, which confirms the serious role of the hospital environment in the spread of infections. Conclusion Nosocomial BSI represents a current problem in Assiut University Hospitals, Egypt. Problems associated with BSI include infection with multidrug resistant pathogens (especially ESBLs) which are difficult to treat and are associated with increased mortality. Of all available anti-microbial agents, carbapenems are the most active and reliable treatment options for infections caused by ESBL isolates. However, overuse of carbapenems may lead to resistance of other Gram-negative organisms.
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Affiliation(s)
- Shaaban H Ahmed
- Department of Public Health and Biostatistics, Faculty of Medicine, Assiut University, Assiut, Egypt.
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149
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Sensitive screening tests for suspected class A carbapenemase production in species of Enterobacteriaceae. J Clin Microbiol 2009; 47:1631-9. [PMID: 19386850 DOI: 10.1128/jcm.00130-09] [Citation(s) in RCA: 163] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The detection of class A serine-carbapenemases among species of Enterobacteriaceae remains a challenging issue. Methods of identification for routine use in clinical microbiology laboratories have not been standardized to date. We developed a novel screening methodology suitable for countries with high basal levels of carbapenem resistance due to non-carbapenemase-mediated mechanisms and standardized several simple confirmatory methods that allow the recognition of bacteria producing class A carbapenemases, including KPC, Sme, IMI, NMC-A, and GES, by using boronic acid (BA) derivatives. A total of 28 genetically unrelated Enterobacteriaceae strains producing several class A carbapenemases were tested. Thirty-eight genetically unrelated negative controls were included. The isolates were tested against imipenem (IPM), meropenem (MEM), and ertapenem (ETP) by MIC and disk diffusion assays in order to select appropriate tools to screen for suspected carbapenemase production. It was possible to differentiate class A carbapenemase-producing bacteria from non-carbapenemase-producing bacteria by using solely the routine IPM susceptibility tests. The modified Hodge test was evaluated and found to be highly sensitive, although false-positive results were documented. Novel BA-based methods (a double-disk synergy test and combined-disk and MIC tests) using IPM, MEM, and ETP, in combination with 3-aminophenylboronic acid as an inhibitor, were designed as confirmatory tools. On the basis of the performance of these methods, a sensitive flow chart for suspicion and confirmation of class A carbapenemase production in species of Enterobacteriaceae was designed. By using this methodology, isolates producing KPC, GES, Sme, IMI, and NMC-A carbapenemases were successfully distinguished from those producing other classes of beta-lactamases (extended-spectrum beta-lactamases, AmpCs, and metallo-beta-lactamases, etc). These methods will rapidly provide useful information needed for targeting antimicrobial therapy and appropriate infection control.
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150
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Patel JB, Rasheed JK, Kitchel B. Carbapenemases in Enterobacteriaceae: Activity, Epidemiology, and Laboratory Detection. ACTA ACUST UNITED AC 2009. [DOI: 10.1016/j.clinmicnews.2009.03.005] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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