Outbreak of infection with multidrug-resistant Klebsiella pneumoniae carrying bla(IMP-8) in a university medical center in Taiwan

An Alliance of Carbapenem-Resistant Klebsiella pneumoniae with Precise Capsular Serotypes and Clinical Determinants: A Disquietude in Hospital Setting

Carbapenemase-resistant Klebsiella pneumoniae (CRKP) is a genuine burden for physicians and researchers. We aimed at carbapenemase resistance and its relation with capsular serotyping in K. pneumoniae and studied some clinical determinants, which may influence the clinical infections. Initially, 61 K. pneumoniae isolates obtained from various clinical specimens were confirmed at the molecular level and then antimicrobial susceptibility test was performed followed by capsular serotyping performed by multiplex PCR. All isolates were subjected to the detection of carbapenemase genes including blaKPC, blaNDM-1, blaOXA-48, blaVIM, and blaIMP. Clinical and demographic data of all patients were reviewed including age, gender, underlying diseases, and the treatment obtained. Multidrug-resistance was a predominant feature in 77% K. pneumoniae strains. Presence of extended-spectrum beta-lactamase was detected phenotypically in 59% K. pneumoniae strains. Carbapenem resistance was noticed phenotypically in 24.6% isolates. blaOXA-48 and blaNDM-1 were the most frequent carbapenemase genes. blaNDM-1 positive isolates correlated with gentamicin, amikacin, imipenem, and meropenem resistance ( $p<0.05$ ). The nosocomial isolates mostly harbored blaOXA-48 gene ( $p<0.02$ ). Amongst all the K. pneumoniae isolates, 59% isolates could be typed and serotype K54 had the highest prevalence followed by K20 and K5. Correlation between the carbapenemase genes, serotype and type of infection showed that blaOXA-48 positive strains had a significant association with K20 serotype and urinary tract infections ( $p=0.2$ ) while, K20 serotype and blaKPC positive strains were significantly associated with wound infections (K20, $p=0.3$ and blaKPC, and $p=0.4$ ). Mucoid phenotype was not found related to presence of specific carbapenemase genes or serotypes except serotype K20 ( $p<0.001$ ). Patients with monotherapy had treatment failure in comparison to the combination therapy for blaKPC-associated infections. In conclusion, the present investigation exhibited the significant association between K20 serotype with blaOXA-48. The predominance of K54 reveals the possibility of endemicity in our hospital setting. K. pneumoniae isolated from wound specimens significantly harbors K20 serotype and blaKPC gene. Comprehensive clinical information and the distribution of antibiotic resistance genes, and serotypes may play important roles in the treatment process.

Resistance Phenotype and Molecular Epidemiology of Carbapenem-Resistant Klebsiella pneumoniae Isolated from Nanjing Children's Hospital in Jiangsu Province, China

Objective

The drug resistance phenotype and molecular epidemiological characteristics of carbapenem-resistant Klebsiella pneumoniae (CRKP) were identified among children in Jiangsu Province, China.

Methods

CRKP strains were collected from the Children’s Hospital of Nanjing Medical University from December 2020 to March 2022. CRKP strains were characterized for further study: antimicrobial susceptibility testing, carbapenem resistance genes and homology analysis.

Results

Among 86 strains of CRKP, 85 carried carbapenemase genes; the dominant gene was bla_KPC-2 (88.2%, 75/85), followed by bla_NDM-1 (4.7%, 4/85), bla_NDM-5 (4.7%, 4/85), bla_IMP-8 (2.3%, 2/85), and bla_OXA-181 (1.2%, 1/85). Among the 86 strains of CRKP, one isolate contained both the bla_NDM-5 and bla_OXA-181 genes, which is the first time that Klebsiella pneumoniae has been shown to jointly carry these genes in China. Another CRKP strain did not carry any carbapenemase gene. MLST analysis identified a total of 10 different sequence types, among which sequence type (ST) 11 was the most common. PFGE analysis identified 75 bla_KPC-2-producing CRKP ST11 strains, of which 68 were dominant clusters distributed among 11 different wards, mainly the neonatal medical centre (18 strains), neonatal surgery (17 strains) and cardiac care unit (CCU) (8 strains) wards.

Conclusion

Clonal dissemination of KPC-2-producing CRKP ST11 was observed in multiple departments. Additionally, non-ST11 strains showed high polymorphism based on molecular typing, indicating increasing diversity in CRKP strains. To our knowledge, this is the first report of NDM-5 and OXA-181-coproducing Klebsiella pneumoniae causing infection in children in China, which poses a significant health risk for paediatric patients. Active surveillance and effective control measures are urgently needed to prevent further transmission of these strains among children.

How Do Transposable Elements Activate Expression of Transcriptionally Silent Antibiotic Resistance Genes?

The rapidly emerging phenomenon of antibiotic resistance threatens to substantially reduce the efficacy of available antibacterial therapies. Dissemination of resistance, even between phylogenetically distant bacterial species, is mediated mainly by mobile genetic elements, considered to be natural vectors of horizontal gene transfer. Transposable elements (TEs) play a major role in this process—due to their highly recombinogenic nature they can mobilize adjacent genes and can introduce them into the pool of mobile DNA. Studies investigating this phenomenon usually focus on the genetic load of transposons and the molecular basis of their mobility. However, genes introduced into evolutionarily distant hosts are not necessarily expressed. As a result, bacterial genomes contain a reservoir of transcriptionally silent genetic information that can be activated by various transposon-related recombination events. The TEs themselves along with processes associated with their transposition can introduce promoters into random genomic locations. Thus, similarly to integrons, they have the potential to convert dormant genes into fully functional antibiotic resistance determinants. In this review, we describe the genetic basis of such events and by extension the mechanisms promoting the emergence of new drug-resistant bacterial strains.

Evaluating NG-Test CARBA 5 Multiplex Immunochromatographic and Cepheid Xpert CARBA-R Assays among Carbapenem-Resistant Enterobacterales Isolates Associated with Bloodstream Infection

Decreased susceptibility to carbapenems in Enterobacterales is an emerging concern. Conventional methods with short turnaround times are crucial for therapeutic decisions and infection control. In the current study, we used the Xpert CARBA-R (Cepheid, Sunnyvale, CA, USA) and the NG-Test CARBA 5 (NG Biotech, Guipry, France) assays for carbapenemase detection in 214 carbapenem-resistant Enterobacterales (CRE) blood isolates. We used the modified carbapenem inactivation method, conventional PCR, and sequencing to determine the production of five common carbapenemase families and their subtypes. We performed wzc-genotyping for all CR-Klebsiella pneumoniae (CRKP) and multilocus sequence typing for all carbapenemase-producing CRE isolates to reveal their genetic relatedness. The results showed a sensitivity of 99.8% and a specificity of 100% by the Xpert assay, and a sensitivity of 100% and a specificity of 99% by the NG-Test in detecting carbapenemases of 84 CRKP isolates with only one (VIM-1+IMP-8) failure in both tests. For CR-Escherichia coli, four carbapenemase-producing isolates were detected accurately for their subtypes. The two major clones of carbapenemase-producing CRKP isolates in Taiwan were ST11-K47 producing KPC-2 (n = 47) and ST11-K64 producing OXA-48-like (n = 9). Our results support the use of either test in routine laboratories for the rapid detection of common carbapenemases. Caution should be taken using the Xpert assay in areas with a high prevalence of CRE carrying bla_IMP-8. IMPORTANCE Carbapenemase-producing Enterobacterales (CPE) are emerging worldwide, causing nosocomial outbreaks and even community-acquired infections since their appearance 2 decades ago. Our previous national surveillance of CPE isolates in Taiwan identified five carbapenemase families (KPC, OXA, NDM, VIM, and IMP) with the KPC-2 and OXA-48-like types predominant. Timely detection and classification of carbapenemases in CPE may be a useful test to guide optimal therapy and infection control. Genetic detection methods using the Xpert CARBA-R assay and the immunochromatographic assay using the NG-Test CARBA 5 have been validated with the advantage of short turnaround time. Our study demonstrated that the NG and Xpert assays are convenient methods to accurately identify carbapenemases in carbapenem-resistant Klebsiella pneumoniae and carbapenem-resistant Escherichia coli blood isolates. Detecting IMP variants remains challenging, and the results of Xpert CARBA-R assay should be carefully interpreted.

Klebsiella pneumoniae Harboring Carbapenemase Genes in Taiwan: Its Evolution over 20 Years, 1998-2019

Klebsiella pneumoniae (K. pneumoniae) is an important pathogen causing various types of human infections in Taiwan. Carbapenemases have increasingly been reported in Enterobacterales in the past two decades. Carbapenemase-producing K. pneumoniae (CPKP), a major resistance concern that has emerged during the last decade, has become a global threat, with its related infections associated with high morbidity and mortality; however, therapeutic options for CPKP-associated infections are limited. Carbapenemases - including K. pneumoniae carbapenemases (KPC)-2, New Delhi metallo-β-lactamase (NDM)-1, Verona integron-encoded metallo-β-lactamase (VIM)-1, imipenemase (IMP)-1, and oxacillinase (OXA)-48 - have been reported worldwide, with a marked prevalence in different countries or areas of the world. Understanding the epidemiology of carbapenemase producers is important for the prevention of their expansion. This review examined the evolution of CPKP in the last two decades to better understand the role of CPKP in Taiwan. It discovered that the endemicity has changed from IMP-8, NDM-1 and VIM-1 to the most common KPC-2 and rapidly emerging OXA-48. Resistance epidemiology, genetic background, virulence factors, therapy, and outcomes are discussed in this paper.

Molecular Characterization of Carbapenem Resistant Klebsiella pneumoniae in Malaysia Hospital

The emergence of carbapenem-resistant Klebsiella pneumoniae (CRKP) is a great concern, as carbapenems are the last-line therapy for multidrug-resistant Gram-negative bacteria infections. This study aims to report the epidemiology of CRKP in a teaching hospital in Malaysia based on the molecular genotypic and clinical characteristics of the isolates. Sixty-three CRKP strains were isolated from a tertiary teaching hospital from January 2016 until August 2017. Carbapenemase genes were detected in 55 isolates, with bla_OXA-48 (63.5%) as the predominant carbapenemase gene, followed by bla_NDM (36.5%). At least one porin loss was detected in nine isolates. Overall, 63 isolates were divided into 30 clusters at similarity of 80% with PFGE analysis. Statistical analysis showed that in-hospital mortality was significantly associated with the usage of central venous catheter, infection or colonization by CRKP, particularly NDM-producers. In comparison, survival analysis using Cox proportional hazards regression identified a higher hazard ratio for patients with a stoma and patients treated with imipenem but a lower hazard ratio for patients with NDM-producing CRKP. OXA-48 carbapenemase gene was the predominant carbapenemase gene in this study. As CRKP infection could lead to a high rate of in-hospital mortality, early detection of the isolates was important to reduce their dissemination.

Gram-negative bacteria as causative agents of ventilator-associated pneumonia and their respective resistance mechanisms

Ventilator-associated pneumonia (VAP) is a serious and common complication in patients admitted to intensive care unit (ICU) and contributes to mortality. Multidrug Gram-negative bacteria such as Acinetobacter baumannii, Pseudomonas aeruginosa, and Klebsiella pneumoniae are frequently associated with VAP in ICU. A prospective study was set up in three ICUs of the University Hospital Center Zagreb and one ICU in General Hospital Pula from September 2017 to March 2018. Antibiotic susceptibility was determined by broth microdilution method. Production of extended-spectrum β-lactamases (ESBLs) was determined by double-disk synergy test and carbapenemases by Hodge and carbapenem inactivation method (CIM). The genes encoding ESBLs, carbapenemases of class A, B and D and qnr genes were determined by PCR. In total 97 Gram-negative bacteria isolates were analyzed. P. aeruginosa demonstrated high resistance rates for imipenem and meropenem with 74% and 68% of resistant strains, respectively. Moderate resistance rates were observed for ceftazidime andpiperacillin/tazobactam, ciprofloxacin and gentamicin (44%). All except three A. baumannii isolates, were resistant to carbapenems and to all other antibiotics apart from colistin and amikacin. Eight A. baumannii isolates were positive for bla_OXA-23 and 12 for bla_OXA-24 genes. Four K. pneumoniae and two E. cloacae strains were ESBL positive and harboured group 1 of CTX-M β-lactamases. Three P. mirabilis strains were positive for plasmid-mediated ampC β-lactamase of CMY family. Two carbapenem-resistant K. pneumoniae harboured OXA-48 and one carbapenem-resistant E. cloacae VIM-1. A high proportion of multidrug-resistant P. aeruginosa, K. pneumoniae and extensively resistant A. baumannii was reported. Acquired resistance mechanisms, mainly production of carbapenemases and ESBLs were dominant in A. baumannii and K. pneumoniae, respectively. Resistance of P. aeruginosa isolates was more likely due to upregulation of efflux pumps or porin loss. A marked diversity of β-lactamases was identified in Enterobacteriaceae.

Occurrence of bla genes encoding carbapenem-resistant Pseudomonas aeruginosa and Acinetobacter baumannii from Intensive Care Unit in a tertiary care hospital

CONTEXT:

ICU shows increasing incidence of infection associated with the use of invasive procedures for the diagnostic purpose as well as the indiscriminate use of antibiotics. Pseudomonas aeruginosa and Acinetobacter species are “very successful” pathogen and the emergence of the Metallo-β-Lactamases (MBL) is becoming a therapeutic challenge.

AIMS:

To isolate the Nonfermenting Gram negative bacilli from the ICU samples. To identify the metallo betalactamase producers and to detect the bla gene presence among the Pseudomonas aeruginosa and Acinetobacter baumannii.

SETTINGS AND DESIGN:

The Nonfermenting Gram negative bacilli isolates from the ICU samples were taken over for 5 years (2009-2014) in a tertiary care hospital.

METHODS AND MATERIALS:

The isolates of Pseudomonas species and Acinetobacter species were confirmed by API analyser and processed according to standard procedures. Detection of the MBL producers were done by E strip method and subjected for bla gene detection by PCR method.

RESULTS:

In our study a total of 195 isolates of NFGNB were obtained from various ICU. Of these MBL producers, 26 % were Pseudomonas aeruginosa and 25 % were Acinetobacter baumannii. The subtypes of bla_VIM MBL producing P.aeruginosa were 26%. The predominant gene coding for MBL activity in A.baumannii were found to be bla_OXA gene 11.9%. The gene accession numbers were KF975367, KF975372.

CONCLUSIONS:

We have to control the development and dissemination of these superbugs among the ICU's.

First Italian outbreak of VIM-producing Serratia marcescens in an adult polyvalent intensive care unit, August-October 2018: A case report and literature review

BACKGROUND

Carbapenem-resistant Enterobacteriaceae has become a significant public health concern as hospital outbreaks are now being frequently reported and these organisms are becoming difficult to treat with the available antibiotics.

CASE SUMMARY

An outbreak of VIM-producing Serratia marcescens occurred over a period of 11 wk (August, 1 to October, 18) in patients admitted to the adult polyvalent intensive care unit of the University of Campania “Luigi Vanvitelli” located in Naples. Four episodes occurred in three patients (two patients infected, and one patient colonized). All the strains revealed the production of VIM.

CONCLUSION

After three decades of carbapenem antibiotics use, the emergence of carbapenem-resistance in Enterobacteriaceae has become a significant concern and a stricter control to preserve its clinical application is mandatory. This is, to our knowledge, the first outbreak of VIM-producing Serratia marcescens in Europe. Surveillance policies must be implemented to avoid future outbreaks.

Infections Caused by Carbapenem-Resistant Enterobacteriaceae: An Update on Therapeutic Options

Carbapenems are considered as last-resort antibiotics for the treatment of infections caused by multidrug-resistant Gram-negative bacteria. With the increasing use of carbapenems in clinical practice, the emergence of carbapenem-resistant pathogens now poses a great threat to human health. Currently, antibiotic options for the treatment of carbapenem-resistant Enterobacteriaceae (CRE) are very limited, with polymyxins, tigecycline, fosfomycin, and aminoglycosides as the mainstays of therapy. The need for new and effective anti-CRE therapies is urgent. Here, we describe the current understanding of issues related to CRE and review combination therapeutic strategies for CRE infections, including high-dose tigecycline, high-dose prolonged-infusion of carbapenem, and double carbapenem therapy. We also review the newly available antibiotics which have potential in the future treatment of CRE infections: ceftazidime/avibactam, which is active against KPC and OXA-48 producers; meropenem/vaborbactam, which is active against KPC producers; plazomicin, which is a next-generation aminoglycoside with in vitro activity against CRE; and eravacycline, which is a tetracycline class antibacterial with in vitro activity against CRE. Although direct evidence for CRE treatment is still lacking and the development of resistance is a concern, these new antibiotics provide additional therapeutic options for CRE infections. Finally, we review other potential anti-CRE antibiotics in development: imipenem/relebactam and cefiderocol. Currently, high-dose and combination strategies that may include the new β-lactam/β-lactamase inhibitors should be considered in severe CRE infections to maximize treatment success. In the future, when more treatment options are available, therapy for CRE infections should be individualized and based on molecular phenotypes of resistance, susceptibility profiles, disease severity, and patient characteristics. More high-quality studies are needed to guide effective treatment for infections caused by CRE.

Effectiveness of healthcare worker screening in hospital outbreaks with gram-negative pathogens: a systematic review

Background

Identifying the source of an outbreak is the most crucial aspect of any outbreak investigation. In this review, we address the frequently discussed question of whether (rectal) screening of health care workers (HCWs) should be carried out when dealing with outbreaks caused by gram negative bacteria (GNB).

A systematic search of the medical literature was performed, including the Worldwide Outbreak Database and PubMed. Outbreaks got included if a HCW was the source of the outbreak and the causative pathogen was an Escherichia coli, Klebsiella spp., Enterobacter spp., Serratia spp., Pseudomonas aeruginosa, or Acinetobacter baumannii.

This was true for 25 articles in which there were 1196 (2.1%) outbreaks due to GNB, thereof 14 HCWs who were permanently colonized by the outbreak strain. Rectal screening of HCWs was helpful in only 2 of the 1196 (0.2%) outbreaks. Instead, the hands of HCWs served as a reservoir for the outbreak strain in at least 7 articles – especially when they suffered from onychomycosis or used artificial fingernails or rings.

Conclusion

Due to very weak evidence, we do not recommend rectal screening of HCWs in an outbreak situation with GNB. However, besides a critical review of hand hygiene habits, it might be useful to examine the hands of staff carefully. This measure is cheap, quick to perform, and seems to be quite effective.

Electronic supplementary material

The online version of this article (10.1186/s13756-018-0330-4) contains supplementary material, which is available to authorized users.

Cystatin C peptidomimetic derivative with antimicrobial properties as a potential compound against wound infections

A peptidomimetic called A20 (Cystapep 1) structurally based upon the N-terminal fragment of human cystatin C is known to have strong antibacterial properties. A20 is characterized by high activity against several bacterial strains often isolated from infected wounds, including methicillin-resistant S. aureus (MRSA). In this work we wanted to explore the therapeutic potential of A20 in the treatment of wound infections. We examined, cytotoxicity, allergenicity and impact of A20 on the proliferation and viability of human keratinocytes. Furthermore, the previously described antimicrobial action of A20has been confirmed here with reference strains of bacteria and extended by several other species. The A20 was highly active against Gram-positive bacteria with minimal inhibitory (MIC) and minimal bactericidal concentrations (MBC) between 8 and 128μg/mL. A20 did not affect proliferation of primary human keratinocytes in concentrations up to 50μg/mL. At the same time, it did not activate Peripheral Blood Mononuclear Cells (PBMCs), including basophils or neutrophils in vitro. Interestingly A20 was found to display immunomodulatory functions as it influences the production of Th2 cytokines (IL-4 and IL-13) by activated PBMCs. It was also resistant to degradation for at least 48h in human plasma. The results indicate that A20 is effective against the multiantibiotic-resistant bacteria and has a high safety profile, which makes it a promising antimicrobial drug candidate.

Outbreak of Imipenemase-1-Producing Carbapenem-Resistant Klebsiella pneumoniae in an Intensive Care Unit

Background

Carbapenem-resistant Enterobacteriaceae (CRE) with acquired metallo β-lactamase (MBL) resistance have been increasingly reported worldwide and associated with significant mortality and morbidity. Here, an outbreak of genetically related strains of Klebsiella pneumoniae producing the imipenemase (IMP)-1 MBL in a medical intensive care unit (MICU) in Korea is reported.

Methods

Since isolating carbapenem-resistant K. pneumoniae (CRKP) at the MICU of the hospital on August 10, 2011, surveillance cultures for CRE in 31 hospitalized patients were performed from August to September 2011. Carbapenem resistance was determined based on the disk diffusion method outlined in the Clinical and Laboratory Standards Institute guidelines. Polymerase chain reaction (PCR) was performed for genes coding for β-lactamase. Associations among isolates were assessed via pulsed-field gel electrophoresis (PFGE). In addition, a surveillance study of environmental cultures and health-care workers (HCWs) was conducted in the MICU during the same time frame.

Results

During the study period, non-duplicated CRKP specimens were discovered in four patients in the MICU, suggestive of an outbreak. On August 10, 2011, CRKP was isolated from the sputum of a 79-year-old male patient who was admitted to the MICU. A surveillance study to detect additional CRE carriers by rectal swab revealed an additional three CRKP isolates. PCR and sequencing of the four isolates identified the presence of the IMP-1 gene. In addition, PFGE showed that the four isolated strains were genetically related. CRE was not identified in specimens taken from the hands of HCWs or other environmental sources during surveillance following the outbreak. Transmission of the carbapenemase-producing Enterobacteriaceae strain was controlled by isolation of the patients and strict contact precautions.

Conclusions

This study shows that rapid and systemic detection of CRE and strict infection controls are important steps in preventing nosocomial transmission.

Altered Outer Membrane Transcriptome Balance with AmpC Overexpression in Carbapenem-Resistant Enterobacter cloacae

The growing incidence of multidrug-resistant (MDR) bacteria is an emerging challenge in modern medicine. The utility of carbapenems, considered “last-line” agents in therapy of infections caused by MDR pathogens, is being diminished by the growing incidence of various resistance mechanisms. Enterobacter cloacae have lately begun to emerge as an important pathogen prone to exhibiting multiple drug resistance. We aimed to investigate the molecular basis of carbapenem-resistance in 44 E. cloacae clinical strains resistant to at least one carbapenem, and 21 susceptible strains. Molecular investigation of 65 E. cloacae clinical strains was based on quantitative polymerase chain reaction (qPCR) allowing for amplification of ampC, ompF, and ompC transcripts, and analysis of nucleotide sequences of alleles included in MLST scheme. Co-operation of three distinct carbapenem resistance mechanisms has been reported—production of OXA-48 (5%), AmpC overproduction (97.7%), and alterations in outer membrane (OM) transcriptome balance. Carbapenem-resistant E. cloacae were characterized by (1.) downregulation of ompF gene (53.4%), which encodes protein with extensive transmembrane channels, and (2.) the polarization of OM transcriptome-balance (79.1%), which was sloped toward ompC gene, encoding proteins recently reported to possess restrictive transmembrane channels. Subpopulations of carbapenem-susceptible strains showed relatively high degrees of sequence diversity without predominant types. ST-89 clearly dominates among carbapenem-resistant strains (88.6%) suggesting clonal spread of resistant strains. The growing prevalence of pathogens resistant to all currently available antimicrobial agents heralds the potential risk of a future “post-antibiotic era.” Great efforts need to be taken to explore the background of resistance to “last resort” antimicrobials.

Molecular epidemiology of carbapenem-resistant Klebsiella pneumoniae in Greece

Hospital infections caused by carbapenem-resistant Klebsiella pneumoniae (CRKP) constitute a worldwide problem associated with high rates of treatment failure and mortality. In Greece, CRKP have emerged in 2002 due to VIM carbapenemase production and later due to KPC, NDM and OXA-48-like carbapenemases that have become endemic. The molecular epidemiology of CRKP strains is dynamic, as antibiotic consumption and worldwide traveling are strongly associated with global spread of CRKP isolates. Lately, porin defects, such as disruption of OmpK35 and production of OmpK36 variant, have also contributed to carbapenem resistance. In the coming years, the high prevalence of CRKP will require intense infection control measures, while novel molecular patterns may appear. To our knowledge, this is the first review analyzing the molecular epidemiology of CRKP strains in Greece.

Characteristics and management of Enterobacteriaceae harboring IMP-4 or IMP-8 carbapenemase in a tertiary hospital

BACKGROUND

The emergence of Enterobacteriaceae harboring IMP-4 or IMP-8 carbapenemases is rare. We report an occurrence of Enterobacteriaceae harboring IMP-4 or IMP-8 carbapenemases in a Chinese tertiary care hospital from November 2010 to December 2012.

METHODS

The clinical characteristics of 30 patients were described. The genetic relationship of isolates was determined by pulsed-field gel electrophoresis (PFGE). Carbapenemases were detected by modified Hodge test (MHT) and polymerase chain reactions (PCRs). Amplicons were sequenced and blasted to determine the genotype.

RESULTS

Most infected patients were from intensive care unit and had complex and serious underlying illnesses requiring mechanical ventilation. PFGE revealed that Klebsiella pneumoniae showed two major PFGE types. Two Klebsiella oxytoca had an indistinguishable PFGE pattern, while four Enterobacter cloacae were different strains. The sequencing studies showed Enterobacteriaceae harboring IMP-4 or IMP-8 carbapenemase in the 23 infected patients. The majority of patients had infections with the carbapenemase-producing Enterobacteriaceae (CPE) strain, most were successfully treated with a range of antibiotics and discharged.

CONCLUSION

It is important to maintain a high index of suspicion to screen for carbapenemase-producing Enterobacteriaceae strains. Rapid identification of these strains and implementation of stringent procedures are the key to prevent major outbreaks in a hospital setting.

Emergence of Carbapenemase Producing Klebsiella Pneumonia and Spread of KPC-2 and KPC-17 in Taiwan: A Nationwide Study from 2011 to 2013

The emergence of carbapenemase-producing Klebsiella pneumoniae (CPKP) has become a great concern worldwide. In this study, 994 non-duplicate, carbapenem non-susceptible Klebsiella pneumonia isolates were collected in Taiwan from 2011 to 2013 for detection of the carbapenemase genes, assessment of antimicrobial susceptibility and molecular epidemiology studies. Of these 994 isolates, 183 (18.4%) had carbapenemase genes: 157 (15.8%) KPC (145 KPC-2 and 12 KPC-17), 16 (1.6%) IMP-8, 9 (0.9%) VIM-1, and 1 (0.1%) NDM-1. KPC had the highest prevalence rate among the carbapenemases and represented a major epidemic clone circulating in Taiwan. The ST512 and ST258 KPC-2 KPs were first identified in Taiwan and were grouped into a small cluster in the PFGE profile. In addition, the genetic structure encompassing the bla_KPC gene of the ST512 and ST258 isolates showed a different pattern from that of other KPC isolates. ST11 may be a major sequence type circulating in Taiwan, although a specific minor clone has begun to be observed. This is the first report of ST258 and ST512 KPC-2 KP isolates in Taiwan, whether ST258 and ST512 will become the next endemic problems in Taiwan should be closely monitored.

Molecular characteristics of carbapenemase-producing Enterobacteriaceae in China from 2008 to 2011: predominance of KPC-2 enzyme

Among 228 carbapenem-nonsusceptible Enterobacteriaceae isolated in China, 65 were carbapenemase-producing Enterobacteriaceae (CPE). Among them, 41, 22, 1, and 1 produced KPC-2, IMP-4, IMP-8, and IMP-1, respectively. KPC-2-producing CPE showed higher resistance than IMP-4-producing ones. Furthermore, the first outbreak of ST11 KPC-2-producing Klebsiella pneumoniae in a Beijing second-degree hospital was identified.

Bloodstream infections caused by carbapenemase-producing Klebsiella pneumoniae: a clinical perspective

Dissemination of carbapenemase-producing Klebsiella pneumoniae (CP-Kp) has caused a public health crisis that can be paralleled with that caused by the spread of MRSA. CP-Kps, being multidrug-resistant, mainly affect patients with severe underlying conditions in the acute-healthcare setting. CP-Kps are responsible for a variety of life-threatening infections including bacteremia and pneumonia. The shortage of therapeutic options has forced clinicians to use colistin as well as tigecycline, a novel bacteriostatic agent. Although both drugs are generally active in vitro against CP-Kps, therapeutic failures, especially in bacteremias, are quite common. The authors suggest here, after reviewing the literature, that use of the latter drugs should be re-assessed and optimized. The authors have also summarized experimental and clinical data indicating that exploitation of the pharmacokinetic/pharmacodynamic features of carbapenems may provide solutions in bloodstream infections caused by CP-Kps with low-level resistance to the latter drugs. Most importantly, there is evidence that monotherapy must be avoided.

Trends in Klebsiella pneumoniae carbapenemase-positive K. pneumoniae in US hospitals: report from the 2007-2009 SENTRY Antimicrobial Surveillance Program

We report the prevalence of carbapenemase-positive Klebsiella pneumoniae among clinical isolates collected from US medical centers (n = 42) from 2007-2009 through the SENTRY Antimicrobial Surveillance Program. Isolates with imipenem or meropenem MIC ≥ 2 μg/mL were screened by PCR for various carbapenemase genes. Of 2049 K. pneumoniae isolates, 126 (6.1%) were non-susceptible to imipenem or meropenem. blaKPC was identified in 113 isolates (5.5%). No other carbapenemase genes were identified. For US regions combined, prevalence of K. pneumoniae carbapenemase (KPC)-positive isolates were 5.9% in 2007, 4.9% in 2008, and 5.7% in 2009. Rates were highest in the Mid-Atlantic region (28.6% overall), with fluctuation over time (29%, 23%, and 33% from 2007-2009), followed by the East North Central region (2.4% overall), with a slightly increasing trend (nil, 3.1%, 3.8% from 2007-2009). All KPC-positive organisms were carbapenem non-susceptible according to updated CLSI breakpoints, although all but one was similarly classified according to previous breakpoints.

First report of KPC-producing Klebsiella pneumoniae in Croatia

In February 2011, a 78-year-old male patient was admitted to Clinical Hospital Center Zagreb with subdural haematoma. Klebsiella pneumoniae with reduced susceptibility to carbapenems was isolated. PCR revealed the presence of bla(KPC), bla(TEM), and bla(SHV) genes. Sequencing of bla(KPC) gene identified K. pneumoniae carbapenemase (KPC)-2 beta-lactamase. The strain belonged to ST37 clone by multilocus sequence typing. Infection control efforts limited the spread of KPC-producing clone of K. pneumoniae in our hospital so far. To our knowledge, this is the first report of a KPC-producing K. pneumoniae in Croatia.

Carbapenemases in Klebsiella pneumoniae and other Enterobacteriaceae: an evolving crisis of global dimensions

SUMMARY

The spread of Enterobacteriaceae, primarily Klebsiella pneumoniae, producing KPC, VIM, IMP, and NDM carbapenemases, is causing an unprecedented public health crisis. Carbapenemase-producing enterobacteria (CPE) infect mainly hospitalized patients but also have been spreading in long-term care facilities. Given their multidrug resistance, therapeutic options are limited and, as discussed here, should be reevaluated and optimized. Based on susceptibility data, colistin and tigecycline are commonly used to treat CPE infections. Nevertheless, a review of the literature revealed high failure rates in cases of monotherapy with these drugs, whilst monotherapy with either a carbapenem or an aminoglycoside appeared to be more effective. Combination therapies not including carbapenems were comparable to aminoglycoside and carbapenem monotherapies. Higher success rates have been achieved with carbapenem-containing combinations. Pharmacodynamic simulations and experimental infections indicate that modification of the current patterns of carbapenem use against CPE warrants further attention. Epidemiological data, though fragmentary in many countries, indicate CPE foci and transmission routes, to some extent, whilst also underlining the lack of international collaborative systems that could react promptly and effectively. Fortunately, there are sound studies showing successful containment of CPE by bundles of measures, among which the most important are active surveillance cultures, separation of carriers, and assignment of dedicated nursing staff.

Population-based incidence of carbapenem-resistant Klebsiella pneumoniae along the continuum of care, Los Angeles County

OBJECTIVE

Carbapenem-resistant Klebsiella pneumoniae (CRKP) is an emerging multidrug-resistant pathogen associated with higher mortality, longer hospital stays, and increased costs. CRKP was thought to be sporadic in Los Angeles County (LAC); however, the actual incidence is unknown. To address this, LAC declared CRKP a laboratory-reportable disease on June 1, 2010.

DESIGN

Laboratory-based community-wide surveillance.

PATIENTS

Any individual who was identified as CRKP positive. CRKP was defined as a K. pneumoniae isolate resistant to all carbapenems by 2010 Clinical and Laboratory Standards Institute criteria.

METHODS

Laboratory directors of 102 LAC acute care hospitals (ACHs) and 5 reference laboratories were to submit susceptibility testing results for all CRKP-positive specimens. Positive specimens from the same patient within the same calendar month of previous culture were excluded.

RESULTS

A total of 814 reports were received from June 1, 2010, through May 31, 2011, from 69 laboratories; 675 (83%) met the case definition. Cases were reported from ACHs (387 [57%]), long-term ACHs (LTACs; 231 [34%]), and skilled nursing facilities (57 [8%]); an outbreak in 1 LTAC was identified. The pooled mean incidence rate in LAC ACHs and LTACs was 0.46 per 1,000 patient-days; the rate in LTACs (2.54 per 1,000 patient-days) was higher than that in ACHs (0.31 per 1,000 patient-days; P < .001). Sixty-five individuals had multiple incidences, accounting for 147 case reports.

CONCLUSION

CRKP is more present in LAC than suspected. Rates were consistently higher in LTACs than in ACHs. Heightened awareness of this problem is needed in all LAC healthcare facilities, as patients access services along the continuum of care.

Molecular typing and resistance mechanisms of imipenem-non-susceptible Klebsiella pneumoniae in Taiwan: results from the Taiwan surveillance of antibiotic resistance (TSAR) study, 2002-2009

We investigated the molecular mechanisms and clonality of imipenem-non-susceptible Klebsiella pneumoniae isolates collected during a Taiwan national surveillance programme, between 2002 and 2009. Genes for carbapenemases, plasmid-borne ampC-type genes and extended-spectrum β-lactamase (ESBL) genes were analysed by PCR. The major porin channels OmpK35 and OmpK36 were studied by SDS-PAGE. Molecular typing was performed with pulsed-field gel electrophoresis (PFGE) and multi-locus sequence typing (MLST). Our study revealed that all 29 of the isolates tested were ESBL producers. Of the K. pneumoniae isolates collected in Taiwan from 2002 to 2009, most (84.6 %, 11/13) imipenem-resistant (MIC >2 mg l(-1)) isolates carried the bla(IMP-8) gene. Isolates with an imipenem MIC of 2 mg l(-1) produced ESBLs with or without DHA-1 in combination with OmpK35/36 loss. PFGE analysis revealed that six small clusters of isolates were clonally related. The MLST grouping results were in concordance with the PFGE results. The predominant sequence types (ST) were ST11, ST48 and ST101. Two novel STs, ST1033 and ST1034, were found. The dominant clone in Taiwan, ST11, has been reported worldwide to be associated with various resistance mechanisms.

Characterization of carbapenemase genes in Enterobacteriaceae species exhibiting decreased susceptibility to carbapenems in a university hospital in Chongqing, China

Background

Our study was to investigate the prevalence of carbapenemase genes in strains of Enterobacteriaceae species exhibiting decreased susceptibility to carbapenems in our hospital.

Methods

The carbapenemase producing Enterobacteriaceae species were confirmed by modified Hodge test (MHT) and EDTA-disc synergy test which indicating the production of class B carbapenemases. PCR and sequencing analysis were used to identify the drug-resistant genes. DNA fingerprinting based on enterobacterial repetitive intergenic consensus (ERIC)-PCR was applied to investigate the homology of Enterobacteriaceae species.

Results

From a collection of 1,472 Enterobacteriaceae species, 18 isolates with decreased susceptibility to carbapenem treatment were identified and 9 of which were positive by MHT, and 6 of which produced class B carbapenemases. PCR and sequencing analysis of the 18 isolates revealed 4 different carbapenemase genes (bla_IMP-8, bla_oxa-1, bla_IMP-26, and bla_oxa-47) in 10 isolates, with the bla_IMP-8 and bla_oxa-1 genes being the most common (60-70% prevalence). ERIC-PCR showed 5, 2, and 2 unique genotypes for Enterobacter cloacae, Escherichia coli, and Klebsiella pneumoniae, respectively. Three E. coli strains isolated from different patients from the urologic surgery department exhibited the same DNA banding pattern, suggesting a possible clonal dissemination. Majority (17/18) of the carbapenem-unsusceptible Enterobacteriaceae species isolates was obtained from the surgery department of our hospital.

Conclusions

The main carbapenemase genes of Enterobacteriaceae species in our hospital were bla_IMP-8 and bla_oxa-1. Prevalence of carbapenem resistance may be existed in surgery department and infection control should be taken for preventing further dissemination of drug-resistant strains.

An observational study on bloodstream extended-spectrum beta-lactamase infection in critical care unit: incidence, risk factors and its impact on outcome

BACKGROUND

The incidence of nosocomial infections caused by extended-spectrum beta-lactamase (ESBL) producing microbes is increasing rapidly in the last few years. However, the clinical significance of infections caused by ESBL-producing bacteria in ICU patients remains unclear. We did a prospective study to look for incidence, risk factors and outcome of these infections in ICU patients.

METHODS

Consecutive isolates of Escherichia coli and Klebsiella pneumoniae in blood cultures were included for the analysis. Patients were divided into two groups based on the production of ESBL. Primary outcome measure was ICU mortality. Logistic regression analysis was done to identify risk factors for ESBL production.

RESULTS

Among the 95 isolates tested, 73 (76.8%) produced ESBL. Transfer from other hospitals or wards (OR 3.65; 95% CI: 1.3-10.1 and RR 1.35; 95% CI: 1.05-1.73) and previous history of antibiotics usage (OR 3.54; 95% CI: 1.04-11.97 and RR 1.5; 95% CI: 0.89-2.5) were risk factors for ESBL production. There was no significant difference in ICU mortality (p=0.588), need for organ support between two groups.

CONCLUSION

There is a high incidence of ESBL producing organisms causing blood stream infections in critically ill patients. Transfer from other hospitals and previous antibiotic usage are important risk factors for ESBL production. However ESBL production may not be associated with a poorer outcome if appropriate early antibiotic therapy is instituted.

Metallo-β-lactamase-producing Enterobacteriaceae isolates at a Taiwanese hospital: lack of distinctive phenotypes for screening

We investigated the prevalence of metallo-β-lactamases (MBLs) among 1,827 Enterobacteriaceae isolates collected in 2006 and evaluated the VITEK 2 microbiology system, modified Hodge test, and 2 combined disk tests as the screening tools for MBLs by using these isolates and 77 previously characterized IMP-8 producers. The IMP-8 MBL was identified in 18 isolates of 2006, and the IMP-8-positive isolates represented 0.2%, 1.1%, and 5.0% of all Escherichia coli, Klebsiella pneumoniae, and Enterobacter cloacae isolates, respectively. Only one-third of all MBL producers could be recognized by either VITEK 2 or the Hodge test. MBL production could be identified in 38 (40%) of the 95 IMP-8-producing isolates by the combined disk test using meropenem disks supplemented by phenylboronic acid and EDTA, and only 2 (2.1%) isolates gave positive results in the combined disk test using meropenem disks supplemented with dipicolinic acid. Of all IMP-8 producers, 37.9%, 50.5%, and 32.6% were nonsusceptible to tigecycline, fluoroquinolones, and both, respectively. In conclusion, this study demonstrated the lack of distinct phenotypes that could be easily identified among the IMP-8-producing Enterobacteriaceae isolates at a Taiwanese hospital. Continuous surveillance and monitoring are needed because the widespread of tigecycline- and fluoroquinolone-coresistant MBL producers may become a serious therapeutic problem.

Carbapenemase-producing Klebsiella pneumoniae: (when) might we still consider treating with carbapenems?

Infections caused by carbapenemase-producing Klebsiella pneumoniae (CPKP) are increasing in frequency worldwide. CPKP isolates exhibit extensive drug resistance phenotypes, complicate therapy, and limit treatment options. Although CPKP isolates are often highly resistant to carbapenems, a proportion of these have relatively low MICs for carbapenems, raising the question of whether this class of agents has any therapeutic potential against CPKP infections. Results from animal studies and patient outcome data indicate that carbapenems retain meaningful in vitro activity against CPKP isolates with carbapenem MICs of ≤ 4 mg/L. Accumulating clinical experience also suggests that the therapeutic efficacy of carbapenems against CPKP isolates with MICs of ≤ 4 mg/L is enhanced when these agents are administered in combination with another active antibiotic. The results of human pharmacokinetic/pharmacodynamic studies are in line with the above observations; it is highly probable that a high-dose/prolonged-infusion regimen of a carbapenem would attain a time above the MIC value of 50% for CPKP isolates with MICs up to 4 mg/L, ensuring acceptable drug exposure and favourable treatment outcome. The analyses summarized in this review support the notion that carbapenems have their place in the treatment of CPKP infections and that the currently proposed EUCAST clinical breakpoints could direct physicians in making treatment decisions.

Multiresistant Gram-negative infections: a global perspective

PURPOSE OF REVIEW

Multiresistant Gram-negative infections are an increasing problem in hospitals and healthcare facilities worldwide. While much attention has been paid to Gram-positive pathogens such as methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus lately, the importance of Gram-negative nosocomial infections has also been recognized globally.

RECENT FINDINGS

Recent reports have described the spread of carbapenemase-producing Klebsiella pneumoniae across North America. In addition, many strains of Pseudomonas and Acinetobacter in Asia are resistant to all known antibiotics. The global epidemiology of multiresistant Gram-negative pathogens seems to vary by continent. There are very few existing agents which can be used for these pathogens and there are limited options on the horizon. This limited therapeutic armamentarium has been an impetus for novel approaches including combination therapies and increased attention to infection control and prevention efforts.

SUMMARY

Clinicians need to be aware of the rising problem of resistance in nosocomial and community-acquired Gram-negative pathogens. Novel agents are urgently needed to combat these infections and innovative infection control strategies need to be devised to protect our vulnerable patients.

Characteristics of clinical isolates of Acinetobacter genomospecies 10 carrying two different metallo-beta-lactamases

Acquired metallo-beta-lactamase (MBL) production is an important mechanism of carbapenem resistance. To our knowledge, carriage of two different MBLs has not been described previously in Acinetobacter spp. We present the characteristics of five Acinetobacter isolates carrying two different MBL genes. The species of all five Acinetobacter isolates with two different MBL genes were Acinetobacter genomospecies 10, and bla(IMP-1), bla(VIM-2) and bla(SIM-1) may coexist in this species. Minimum inhibitory concentrations (MICs) of imipenem for all five isolates with two different MBLs were >or=32 microg/mL, whilst those for two segregants that lost both MBLs were 0.5 microg/mL. The presence of MBL gene-carrying integrons with identical structures suggested the easily transferable nature of the elements, whilst instability of the MBL genes indicated potentially erroneous phenotypic and genetic characterisation.

Efficacy of calcium-EDTA as an inhibitor for metallo-β-lactamase in a mouse model of Pseudomonas aeruginosa pneumonia

In this study, we have evaluated the efficacy of calcium-EDTA (Ca-EDTA) as an inhibitor of bacterial metalloenzymes, such as metallo-β-lactamase (MBL) and other proteases, in a mouse model of Pseudomonas aeruginosa pneumonia. The simultaneous presence of Ca-EDTA (32 μg/ml) reduced the MICs of imipenem (IPM) in all MBL-producing P. aeruginosa isolates (IMP-1, -2, -7, and -10 and VIM-2) but not non-MBL-producing strains. In the pneumonia model, mice were intranasally infected with MBL-producing P. aeruginosa and then kept under conditions of hyperoxia to mimic ventilator-associated pneumonia. With both intranasal and subcutaneous administrations, Ca-EDTA significantly potentiated survival benefits of IPM compared to those of IPM alone. Ca-EDTA combination therapy induced a significant reduction of the bacterial burden in the lungs (P < 0.05). Furthermore, the inhibition activity of Ca-EDTA against MBL activity was confirmed by using the purified IMP-1 enzyme, which was characterized by a 50% inhibitory concentration (IC(50)) of 55 ± 8.2 μM. Finally, the protective effects of Ca-EDTA were demonstrated by culture supernatant-induced epithelial cell damage and acute lung injury in mice. These data suggest the therapeutic potential of Ca-EDTA not only by the blocking of MBLs but also by neutralizing tissue-damaging metalloproteases in P. aeruginosa infections.

Comparison of BD Phoenix, Vitek 2, and MicroScan automated systems for detection and inference of mechanisms responsible for carbapenem resistance in Enterobacteriaceae

We assessed the ability of three commercial systems to infer carbapenem resistance mechanisms in 39 carbapenemase-producing and 16 other carbapenem-resistant Enterobacteriaceae. The sensitivity/specificity values for "flagging" a likely carbapenemase were 100%/0% (BD Phoenix), 82 to 85%/6 to 19% (MicroScan), and 74%/38% (Vitek 2), respectively. OXA-48 producers were poorly detected, but all systems reliably detected isolates with KPC and most with metallo-carbapenemases.

Reduced susceptibility to carbapenems in Klebsiella pneumoniae clinical isolates associated with plasmid-mediated β-lactamase production and OmpK36 porin deficiency

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.

Development and evaluation of a real-time PCR assay for detection of Klebsiella pneumoniae carbapenemase genes

We developed a novel real-time PCR assay to detect Klebsiella pneumoniae carbapenemases (KPCs) and used this assay to screen clinical isolates of K. pneumoniae and Klebsiella oxytoca for the presence of bla(KPC) genes. The TaqMan real-time PCR assay amplified a 399-bp product from the bla(KPC) gene. The amplicon was designed so that the genes for isoenzymes KPC-1, -2, and -3 could be easily distinguished by subsequent restriction digestion of the amplicon with the enzymes BstNI and RsaI. The assay was validated with reference strains obtained from the Centers for Disease Control and Prevention that contained each of the three described isoenzymes and 69 extended-spectrum beta-lactamase-producing clinical isolates (39 K. pneumoniae and 30 K. oxytoca isolates). Subsequently, the bla(KPC) PCR assay was used to confirm the presence of bla(KPC) genes in any meropenem-resistant Klebsiella spp. The PCR assay detected bla(KPC) in all of the reference strains, in 6 of 7 meropenem-resistant isolates, and in 0 of 62 meropenem-susceptible clinical isolates. The PCR assay was then used to confirm the presence of bla(KPC) in an additional 20 meropenem-resistant isolates from 16 patients. Restriction digestion of the PCR amplicons identified two bla(KPC) gene variants in our patient population: 9 isolates with C and 17 with T at nucleotide 944, consistent with bla(KPC-2) and bla(KPC-3), respectively. The real-time PCR assay is a rapid and accurate method to detect all KPC isoenzymes and was useful in documenting the presence and dissemination of KPC-producing strains in our patient population.

Metallo beta lactamases in Pseudomonas aeruginosa and Acinetobacter species

The multi drug resistant gram negative bacteria especially Pseudomonas aeruginosa and Acinetobacter species are on the rise. The major defense in these bacteria against beta-lactam antibiotics is production of metallo beta lactamases (MBLs) which degrade this group of antibiotics including carbapenems. Till now five main types of MBLs have been described throughout the World--IMP, VIM, SPM, GIM and SIM. A new MBL has been recently reported in P. aeruginosa from Australia--bla AIM-1. There are no standard guidelines by CLSI for detection of these enzymes in various bacteria. A number of phenotypic tests based on different beta lactam-inhibitor combinations are being evaluated and used for routine testing. Regarding the treatment options--colistin, various antibiotic combinations and a few novel antibiotics are being tried and evaluated. Prevention is based on age old practices of strict infection control and judicious use of antibiotics.