Register      Login
Microbiology Australia Microbiology Australia Society
Microbiology Australia, bringing Microbiologists together
RESEARCH ARTICLE

Multi-drug-resistant Gram-negative bacteria

Hanna E Sidjabat , Witchuda Kamolvit , Alexander Wailan and David L Paterson
+ Author Affiliations
- Author Affiliations

The University of Queensland, UQ Centre for Clinical Research
Royal Brisbane and Women’s Hospital Complex
Brisbane, Qld 4029
AustraliaTel: +61 7 3346 6073
Fax: +61 7 3346 5598
Email: h.sidjabat@uq.edu.au

Microbiology Australia 34(1) 43-46 https://doi.org/10.1071/MA13014
Published: 20 March 2013

The increasing prevalence of antibiotic-resistant Gram-negative bacteria is a serious concern not only for humans but also companion animals13. Recent clinical attention has focused on the increasing frequency of Gram-negative pathogens responsible for hospital-acquired infections. In this group, extended-spectrum β-lactamase (ESBL) and carbapenemase producing Enterobacteriaceae, in particular E. coli and K. pneumoniae, as well as carbapenemase producing A. baumannii, have caused major challenges in the past decade. These three groups of organisms will be the focus of this article.


β-lactams are the most widely utilised antimicrobials worldwide for the treatment of infections in humans and animals. β-lactamase production is the most common mechanism of antibiotic resistance, particularly in Gram-negative bacilli. There are four different groups based on the Ambler molecular classification, which categorises the enzyme according to their amino acid sequence, primarily on their active site. Classes A, C and D are serine β-lactamases and Class B are metallo-β-lactamases which require a bivalent metal ion for activity, usually Zn2+ (Table 1)4.


Table 1. Classes of β-lactamase in Enterobacteriaceae and Acinetobacter spp.
Click to zoom


ESBL and CMY-2-like producing Enterobacteriaceae

Two types of cephalosporinases commonly described in human and animal pathogens are ESBLs and CMY-2 like. CMY-2 type of resistance was commonly described in Salmonella and E. coli isolated from food-producing animals5,6. CMY-2 producing E. coli is also relatively common in humans and nearly as common as ESBL producing E. coli7. Nowadays, CTX-M type ESBLs are the most commonly reported β-lactamases both in human and animals. Until the year 2000, TEM and SHV type ESBLs were of great concern and mostly in E. cloacae and K. pneumoniae. However, since mid-2000s, there has been a dramatic shift into the predominance of CTX-M type ESBLs8. In dogs and cats, there have been reports of infections caused by CTX-M type ESBL producing E. coli associated with human infections9,10. In the USA, CTX-M type ESBL, mostly CTX-M-15 occurred at the rate of 7.3% amongst E. coli causing urinary tract infections in dogs9 and caused serious infections, such as liver and bile infection in dogs10. CTX-M producing E. coli was quite common in pig farms in China, with the prevalence of 10.7%11. The presence of this ESBL in farm animal causes a significant threat to public health.


E. coli ST131 clone

E. coli is a leading cause of urinary tract infections in humans and dogs. E. coli can be divided into four phylogenetic groups: A, B1, B2 and D. The virulent extra-intestinal pathogens are usually found in classes B2 and D12. In the last decade, E. coli sequence type (ST) 131 has emerged as a pandemic uropathogenic E. coli causing community and hospital-acquired infections especially urinary tract infections13,14. This clone potentially can harbour a variety of β-lactamase genes; however, it is most strongly associated with CTX-M-15 ESBL. In addition, the pandemic clone E. coli ST131 also belonged to the phylogenetic group B2, the highly virulent group of ExPEC. The combination of virulence and antimicrobial resistance may give E. coli ST131 a fitness advantage over other E. coli strains, which highlights the widespread and successful dissemination of E. coli ST131.

E. coli ST131 is also represented among resistant isolates in companion and farm animals. A European study determined the presence of E. coli ST131 which mostly produced CTX-M-15, comprising 5.6% of ESBL-producing E. coli isolates recovered from companion animals15. In Australia, E. coli ST131 accounted for 7.2% of isolates from companion animals16. Transmission between dogs and cats sharing the same clone, E. coli ST131, has been described previously17. Dogs in particular have been identified as a possible reservoir not only for ST131, but also for extra-intestinal pathogenic E. coli (ExPEC) in general for the transmission to other pets and humans18. E. coli ST131 has also been reported from poultry and pig farms in Spain19. In this instance, both companion and farm animals can be the reservoirs for E. coli ST131 and other cephalosporin-resistant E. coli. Studies on retail meat for human consumption have found E. coli indistinguishable from human E. coli causing urinary tract infections (UTIs) and E. coli ST131 was isolated from chicken20. Further studies are urgently needed to investigate the pathways of transmission between humans and animals to determine whether isolates found in retail meat and livestock pose an imminent threat to humans.


Carbapenem-resistant Enterobacteriaceae (CRE)

Various Enterobacteriaceae confer antibiotic resistance by producing enzymes such as carbapenemases. The carbapenemase modifies the carbapenems through the hydrolysis of the antibiotic and has been defined into different classes using the Ambler classification system. The resistance in Enterobacteriaceae is found within Ambler class A (KPC – K. pneumoniae Carbapenemase), class B (metallo-β-lactamases) and class D (OXA – oxacillinases) (Table 1)21. KPC-type β-lactamases, are the most frequent cause of carbapenem resistance in the United States and has spread rapidly to Europe22,23. The most recent class B enzyme identified is the New Delhi Metallo–β-lactamase (NDM-1) in 200924. These enzymes are frequently found in K. pneumoniae and E. coli. The majority of NDM-producing isolates are found on the Indian subcontinent25.

The recent emergence of CRE represents a significant threat and has also drawn substantial media attention, especially through the spread of the NDM-126. The NDM-1 gene was first described from a Swedish patient who travelled to India in 2008, but this gene has now spread worldwide25. NDM-1 can be found in numerous species of Enterobacteriaceae, including E. coli and various species of Acinetobacter spp.27. NDM gene is able to spread rapidly by residing in self-transferrable plasmids. NDM-1 producers have been isolated from water and other environmental samples in India28. A total of 88 NDM-1 cases were reported in the United Kingdom (up to March 201129); 13 NDM-1 cases were reported in the USA30. Eight cases have been reported in Australia. Most cases identified outside India and Pakistan, including those in Australia and New Zealand, were related to travel and/or medical treatment in India or Pakistan24,31. There have been several cases due to local acquisition of the NDM producers or without travel history in Europe and Asia32,33. The rapid spread of NDM has moved outside the hospital. Studies in China found NDM-1 producing Acinetobacter spp. from hospital waste34 and food of animal origin35. The worldwide spread of NDM producers in hospitals and the environment are clearly a real threat.


Carbapenem-resistant Acinetobacter baumannii

A. baumannii has gained recognition as a major nosocomial pathogen in recent years36 predominantly affecting immunocompromised or critically ill patients. It causes a wide range of infections including pneumonia, bacteraemia and infections of the skin, bone, urinary tract and central nervous system36. The remarkable ability of A. baumannii to up-regulate or acquire antibiotic resistance determinants makes the bacterium a significant nosocomial pathogen. Resistance to carbapenems has been reported worldwide, including Australia3739. Many genotypes conferring such resistance have been found to belong to European clones (EU) I, II or III37. Although several molecular mechanisms were responsible for conferring carbapenem resistance, the most common is the production of class D β-lactamases, OXA-type carbapenemases. Class B metallo-β-lactamases (such as IMP-, VIM- and SIM-types) are occasionally identified in A. baumannii isolates which have acquired these resistant determinants via class 1 integrons (Table 1)40. Alteration of penicillin-binding proteins and loss of outer membrane proteins41, efflux pump mechanisms and other β-lactamases are also found in A. baumannii42.

The OXA-type carbapenemases identified in A. baumannii include both (i) acquired types (OXA-23-, OXA-24- and OXA-58-like) where their gene clusters have been found either in the chromosome or plasmid and (ii) naturally occurring chromosomal OXA-51-like43. Multiple studies regarding genomic sequences surrounding these genes revealed the pivotal role of insertion sequence (IS) elements. The presence of ISAba1 upstream of blaOXA-23 as well as intrinsic chromosomal blaOXA-51-like provide promoter sequences consequently leading to the over-expression of these downstream genes40,44. ISAba1 and other IS elements, such as ISAba2, ISAba3 and IS8 were shown to enhance the expression of blaOXA-5845. These IS elements play significant roles in the expression of various OXA-genes in A. baumannii. A. baumannii can also be isolated from faeces of slaughtered pigs and cattle46. These strains from animals possessed blaOXA-51-like, however, the resistance islands could not be found and none of the isolates from animals belonged to the European clones I, II and III as the common clones of human A. baumannii strains46.

The rapid spread of multi-drug-resistant bacteria Gram-negative bacteria, especially in nosocomial pathogens; in the past decade underline the importance of infection control precautions in both human and veterinary hospitals. The possibility that farm animals may be the reservoir of resistance mechanisms and the current evidence of spread of the most recent and notorious carbapenem resistance genes demonstrate the need for increased surveillance of antibiotic usage in veterinary and farm animals as well as in humans.



References

[1]  Sanchez, S. et al. (2002) Characterization of multidrug-resistant Escherichia coli isolates associated with nosocomial infections in dogs. J. Clin. Microbiol. 40, 3586–3595.
Characterization of multidrug-resistant Escherichia coli isolates associated with nosocomial infections in dogs.Crossref | GoogleScholarGoogle Scholar |

[2]  Sidjabat, H.E. et al. (2006) Identification of bla CMY-7 and associated plasmid-mediated resistance genes in multidrug-resistant Escherichia coli isolated from dogs at a veterinary teaching hospital in Australia. J. Antimicrob. Chemother. 57, 840–848.
Identification of bla CMY-7 and associated plasmid-mediated resistance genes in multidrug-resistant Escherichia coli isolated from dogs at a veterinary teaching hospital in Australia.Crossref | GoogleScholarGoogle Scholar |

[3]  Sidjabat, H.E. et al. (2006) Emergence and spread of two distinct clonal groups of multidrug-resistant Escherichia coli in a veterinary teaching hospital in Australia. J. Med. Microbiol. 55, 1125–1134.
Emergence and spread of two distinct clonal groups of multidrug-resistant Escherichia coli in a veterinary teaching hospital in Australia.Crossref | GoogleScholarGoogle Scholar |

[4]  Ambler R.P. (1980 ) The structure of beta-lactamases. Phil. Trans. Royal Soc. London. Series B, Biological sciences 289 321 331

[5]  Mataseje, L.F. et al. (2010) Comparison of CMY-2 plasmids isolated from human, animal, and environmental Escherichia coli and Salmonella spp. from Canada. Diagn. Microbiol. Infect. Dis. 67, 387–391.
Comparison of CMY-2 plasmids isolated from human, animal, and environmental Escherichia coli and Salmonella spp. from Canada.Crossref | GoogleScholarGoogle Scholar |

[6]  Winokur, P.L. et al. (2000) Animal and human multidrug-resistant, cephalosporin-resistant salmonella isolates expressing a plasmid-mediated CMY-2 AmpC beta-lactamase. Antimicrob. Agents Chemother. 44, 2777–2783.
Animal and human multidrug-resistant, cephalosporin-resistant salmonella isolates expressing a plasmid-mediated CMY-2 AmpC beta-lactamase.Crossref | GoogleScholarGoogle Scholar |

[7]  Sidjabat, H.E. et al. (2009) Clinical features and molecular epidemiology of CMY-type beta-lactamase-producing Escherichia coli. Clin. Infect. Dis. 48, 739–744.
Clinical features and molecular epidemiology of CMY-type beta-lactamase-producing Escherichia coli.Crossref | GoogleScholarGoogle Scholar |

[8]  Livermore, D.M. et al. (2007) CTX-M: changing the face of ESBLs in Europe. J. Antimicrob. Chemother. 59, 165–174.
CTX-M: changing the face of ESBLs in Europe.Crossref | GoogleScholarGoogle Scholar |

[9]  O’Keefe, A. et al. (2010) First detection of CTX-M and SHV extended-spectrum beta-lactamases in Escherichia coli urinary tract isolates from dogs and cats in the United States. Antimicrob. Agents Chemother. 54, 3489–3492.
First detection of CTX-M and SHV extended-spectrum beta-lactamases in Escherichia coli urinary tract isolates from dogs and cats in the United States.Crossref | GoogleScholarGoogle Scholar |

[10]  Timofte, D. et al. (2011) Detection of extended-spectrum-beta-lactamase-positive Escherichia coli in bile isolates from two dogs with bacterial cholangiohepatitis. J. Clin. Microbiol. 49, 3411–3414.
Detection of extended-spectrum-beta-lactamase-positive Escherichia coli in bile isolates from two dogs with bacterial cholangiohepatitis.Crossref | GoogleScholarGoogle Scholar |

[11]  Tian, G.B. et al. (2009) Detection of CTX-M-15, CTX-M-22, and SHV-2 extended-spectrum beta-lactamases (ESBLs) in Escherichia coli fecal-sample isolates from pig farms in China. Foodborne Pathog. Dis. 6, 297–304.
Detection of CTX-M-15, CTX-M-22, and SHV-2 extended-spectrum beta-lactamases (ESBLs) in Escherichia coli fecal-sample isolates from pig farms in China.Crossref | GoogleScholarGoogle Scholar |

[12]  Johnson, J.R. et al. (2006) Phylogenetic relationships among clonal groups of extraintestinal pathogenic Escherichia coli as assessed by multi-locus sequence analysis. Microbes Infect. 8, 1702–1713.
Phylogenetic relationships among clonal groups of extraintestinal pathogenic Escherichia coli as assessed by multi-locus sequence analysis.Crossref | GoogleScholarGoogle Scholar |

[13]  Rogers, B.A. et al. (2011) Escherichia coli O25b-ST131: a pandemic, multiresistant, community-associated strain. J. Antimicrob. Chemother. 66, 1–14.
Escherichia coli O25b-ST131: a pandemic, multiresistant, community-associated strain.Crossref | GoogleScholarGoogle Scholar |

[14]  Sidjabat, H.E. et al. (2010) Escherichia coli ST131 producing CTX-M-15 in Australia. J. Antimicrob. Chemother. 65, 1301–1303.
Escherichia coli ST131 producing CTX-M-15 in Australia.Crossref | GoogleScholarGoogle Scholar |

[15]  Ewers, C. et al. (2010) Emergence of human pandemic O25:H4-ST131 CTX-M-15 extended-spectrum-beta-lactamase-producing Escherichia coli among companion animals. J. Antimicrob. Chemother. 65, 651–660.
Emergence of human pandemic O25:H4-ST131 CTX-M-15 extended-spectrum-beta-lactamase-producing Escherichia coli among companion animals.Crossref | GoogleScholarGoogle Scholar |

[16]  Platell, J.L. et al. (2010) Clonal group distribution of fluoroquinolone-resistant Escherichia coli among humans and companion animals in Australia. J. Antimicrob. Chemother. 65, 1936–1938.
Clonal group distribution of fluoroquinolone-resistant Escherichia coli among humans and companion animals in Australia.Crossref | GoogleScholarGoogle Scholar |

[17]  Johnson, J.R. et al. (2009) Sharing of Escherichia coli sequence type ST131 and other multidrug-resistant and urovirulent E. coli strains among dogs and cats within a household. J. Clin. Microbiol. 47, 3721–3725.
Sharing of Escherichia coli sequence type ST131 and other multidrug-resistant and urovirulent E. coli strains among dogs and cats within a household.Crossref | GoogleScholarGoogle Scholar |

[18]  Johnson, J.R. et al. (2009) Virulence genotypes and phylogenetic background of fluoroquinolone-resistant and susceptible Escherichia coli urine isolates from dogs with urinary tract infection. Vet. Microbiol. 136, 108–114.
Virulence genotypes and phylogenetic background of fluoroquinolone-resistant and susceptible Escherichia coli urine isolates from dogs with urinary tract infection.Crossref | GoogleScholarGoogle Scholar |

[19]  Cortes, P. et al. (2010) Isolation and characterization of potentially pathogenic antimicrobial-resistant Escherichia coli strains from chicken and pig farms in Spain. Appl. Environ. Microbiol. 76, 2799–2805.
Isolation and characterization of potentially pathogenic antimicrobial-resistant Escherichia coli strains from chicken and pig farms in Spain.Crossref | GoogleScholarGoogle Scholar |

[20]  Vincent, C. et al. (2010) Food reservoir for Escherichia coli causing urinary tract infections. Emerg. Infect. Dis. 16, 88–95.
Food reservoir for Escherichia coli causing urinary tract infections.Crossref | GoogleScholarGoogle Scholar |

[21]  Nordmann, P. et al. (2011) Global spread of Carbapenemase-producing Enterobacteriaceae. Emerg. Infect. Dis. 17, 1791–1798.
Global spread of Carbapenemase-producing Enterobacteriaceae.Crossref | GoogleScholarGoogle Scholar |

[22]  Cantón, R. et al. (2012) Rapid evolution and spread of carbapenemases among Enterobacteriaceae in Europe. Clin. Microbiol. Infect. 18, 413–431.
Rapid evolution and spread of carbapenemases among Enterobacteriaceae in Europe.Crossref | GoogleScholarGoogle Scholar |

[23]  Kitchel, B. et al. (2009) Molecular epidemiology of KPC-producing Klebsiella pneumoniae isolates in the United States: clonal expansion of multilocus sequence type 258. Antimicrob. Agents Chemother. 53, 3365–3370.
Molecular epidemiology of KPC-producing Klebsiella pneumoniae isolates in the United States: clonal expansion of multilocus sequence type 258.Crossref | GoogleScholarGoogle Scholar |

[24]  Yong, D. et al. (2009) Characterization of a new metallo-beta-lactamase gene, bla NDM-1, and a novel erythromycin esterase gene carried on a unique genetic structure in Klebsiella pneumoniae sequence type 14 from India. Antimicrob. Agents Chemother. 53, 5046–5054.
Characterization of a new metallo-beta-lactamase gene, bla NDM-1, and a novel erythromycin esterase gene carried on a unique genetic structure in Klebsiella pneumoniae sequence type 14 from India.Crossref | GoogleScholarGoogle Scholar |

[25]  Nordmann, P. (2012) Carbapenem resistance in Enterobacteriaceae: here is the storm! Trends Mol. Med. 18, 263–272.
Carbapenem resistance in Enterobacteriaceae: here is the storm!Crossref | GoogleScholarGoogle Scholar |

[26]  Walsh, T.R. and Toleman, M.A. (2012) The emergence of pan-resistant Gram-negative pathogens merits a rapid global political response. J. Antimicrob. Chemother. 67, 1–3.
The emergence of pan-resistant Gram-negative pathogens merits a rapid global political response.Crossref | GoogleScholarGoogle Scholar |

[27]  Perry, J.D. et al. (2011) Prevalence of faecal carriage of Enterobacteriaceae with NDM-1 carbapenemase at military hospitals in Pakistan, and evaluation of two chromogenic media. J. Antimicrob. Chemother. 66, 2288–2294.
Prevalence of faecal carriage of Enterobacteriaceae with NDM-1 carbapenemase at military hospitals in Pakistan, and evaluation of two chromogenic media.Crossref | GoogleScholarGoogle Scholar |

[28]  Walsh, T.R. et al. (2011) Dissemination of NDM-1 positive bacteria in the New Delhi environment and its implications for human health: an environmental point prevalence study. Lancet Infect. Dis. 11, 355–362.
Dissemination of NDM-1 positive bacteria in the New Delhi environment and its implications for human health: an environmental point prevalence study.Crossref | GoogleScholarGoogle Scholar |

[29]  UK Health Protection Agency http:www.hpa.org.uk/Topics/InfectiousDiseases/InfectionsAZ/CarbapenemResistance/EpidemiologicalData/. accessed 11 November 2012.

[30]  Centers for Disease Control and Prevention (2012) Carbapenem-resistant Enterobacteriaceae containing New Delhi metallo-beta-lactamase in two patients – Rhode Island, March 2012. MMWR Morb. Mortal. Wkly. Rep. 61, 446–448.

[31]  Sidjabat, H. et al. (2011) Carbapenem resistance in Klebsiella pneumoniae due to the New Delhi Metallo-beta-lactamase. Clin. Infect. Dis. 52, 481–484.
Carbapenem resistance in Klebsiella pneumoniae due to the New Delhi Metallo-beta-lactamase.Crossref | GoogleScholarGoogle Scholar |

[32]  Arpin, C. et al. (2012) NDM-1-producing Klebsiella pneumoniae resistant to colistin in a French community patient without history of foreign travel. Antimicrob. Agents Chemother. 56, 3432–3434.
NDM-1-producing Klebsiella pneumoniae resistant to colistin in a French community patient without history of foreign travel.Crossref | GoogleScholarGoogle Scholar |

[33]  Rimrang, B. et al. (2012) Emergence of NDM-1- and IMP-14a-producing Enterobacteriaceae in Thailand. J. Antimicrob. Chemother. 67, 2626–2630.
Emergence of NDM-1- and IMP-14a-producing Enterobacteriaceae in Thailand.Crossref | GoogleScholarGoogle Scholar |

[34]  Chen, Y. et al. (2011) Emergence of NDM-1-producing Acinetobacter baumannii in China. J. Antimicrob. Chemother. 66, 1255–1259.
Emergence of NDM-1-producing Acinetobacter baumannii in China.Crossref | GoogleScholarGoogle Scholar |

[35]  Wang, Y. et al. (2012) Identification of New Delhi metallo-beta-lactamase 1 in Acinetobacter lwoffii of food animal origin. PLoS ONE 7, e37152.
Identification of New Delhi metallo-beta-lactamase 1 in Acinetobacter lwoffii of food animal origin.Crossref | GoogleScholarGoogle Scholar |

[36]  Peleg, A.Y. et al. (2008) Acinetobacter baumannii: emergence of a successful pathogen. Clin. Microbiol. Rev. 21, 538–582.
Acinetobacter baumannii: emergence of a successful pathogen.Crossref | GoogleScholarGoogle Scholar |

[37]  Higgins, P.G. et al. (2010) Global spread of carbapenem-resistant Acinetobacter baumannii. J. Antimicrob. Chemother. 65, 233–238.
Global spread of carbapenem-resistant Acinetobacter baumannii.Crossref | GoogleScholarGoogle Scholar |

[38]  Post, V. et al. (2010) Evolution of AbaR-type genomic resistance islands in multiply antibiotic-resistant Acinetobacter baumannii. J. Antimicrob. Chemother. 65, 1162–1170.
Evolution of AbaR-type genomic resistance islands in multiply antibiotic-resistant Acinetobacter baumannii.Crossref | GoogleScholarGoogle Scholar |

[39]  Runnegar, N. et al. (2010) Molecular epidemiology of multidrug-resistant Acinetobacter baumannii in a single institution over a 10-year period. J. Clin. Microbiol. 48, 4051–4056.
Molecular epidemiology of multidrug-resistant Acinetobacter baumannii in a single institution over a 10-year period.Crossref | GoogleScholarGoogle Scholar |

[40]  Poirel, L. and Nordmann, P. (2006) Carbapenem resistance in Acinetobacter baumannii: mechanisms and epidemiology. Clin. Microbiol. Infect. 12, 826–836.
Carbapenem resistance in Acinetobacter baumannii: mechanisms and epidemiology.Crossref | GoogleScholarGoogle Scholar |

[41]  Mussi, M.A. et al. (2007) CarO, an Acinetobacter baumannii outer membrane protein involved in carbapenem resistance, is essential for L-ornithine uptake. FEBS Lett. 581, 5573–5578.
CarO, an Acinetobacter baumannii outer membrane protein involved in carbapenem resistance, is essential for L-ornithine uptake.Crossref | GoogleScholarGoogle Scholar |

[42]  Vila, J. et al. (2007) Porins, efflux pumps and multidrug resistance in Acinetobacter baumannii. J. Antimicrob. Chemother. 59, 1210–1215.
Porins, efflux pumps and multidrug resistance in Acinetobacter baumannii.Crossref | GoogleScholarGoogle Scholar |

[43]  Turton, J.F. et al. (2006) Identification of Acinetobacter baumannii by detection of the bla OXA-51-like carbapenemase gene intrinsic to this species. J. Clin. Microbiol. 44, 2974–2976.
Identification of Acinetobacter baumannii by detection of the bla OXA-51-like carbapenemase gene intrinsic to this species.Crossref | GoogleScholarGoogle Scholar |

[44]  Turton, J.F. et al. (2006) The role of ISAba1 in expression of OXA carbapenemase genes in Acinetobacter baumannii. FEMS Microbiol. Lett. 258, 72–77.
The role of ISAba1 in expression of OXA carbapenemase genes in Acinetobacter baumannii.Crossref | GoogleScholarGoogle Scholar |

[45]  Poirel, L. and Nordmann, P. (2006) Genetic structures at the origin of acquisition and expression of the carbapenem-hydrolyzing oxacillinase gene bla OXA-58 in Acinetobacter baumannii. Antimicrob. Agents Chemother. 50, 1442–1448.
Genetic structures at the origin of acquisition and expression of the carbapenem-hydrolyzing oxacillinase gene bla OXA-58 in Acinetobacter baumannii.Crossref | GoogleScholarGoogle Scholar |

[46]  Hamouda, A. et al. (2011) Epidemiology of Acinetobacter baumannii of animal origin. Int. J. Antimicrob. Agents 38, 314–318.
Epidemiology of Acinetobacter baumannii of animal origin.Crossref | GoogleScholarGoogle Scholar |


Biographies

Dr Hanna Sidjabat’s research interest is in molecular epidemiology of plasmids carrying antibiotic resistance genes and genetic context of antibiotic resistance genes.

Witchuda Kamolvit MD is a PhD student studying the genome of OXA-23 producing A. baumannii from Australia and Asian countries.

Alexander Wailan BSc Hons is a PhD student studying the NDM-1 plasmid mobilisation and complete NDM-1 plasmid sequences from Australia, New Zealand and Asian countries.

Prof David Paterson’s research interest includes study of the molecular and clinical epidemiology of infections with antibiotic resistant organisms. The focus of this work is the translation of knowledge into optimal prevention and treatment of these infections.