Epidemiological typing of Enterobacter aerogenes

The applicability of Enterobacter cloacae and Klebsiella typing reagents for classifying clinical strains of Enterobacter aerogenes was evaluated. Of 75 strains, none were agglutinated by E. cloacae O antisera or were sensitive to E. cloacae bacteriophages. In contrast, 70 strains reacted with Klebsiella capsular antisera. Two-thirds of the strains were lysed by Klebsiella typing phages. A set of five E. aerogenes bacteriocin producers classified 92% of strains into 15 sensitivity types. In conclusion, E. aerogenes may be typed with Klebsiella reagents, and the simple bacteriocin test provides further discrimination between strains. The limited number of capsular antigens in the species and their apparent similarity to Klebsiella capsular antigens warrant further investigation.     

Emergence of Enterobacter aerogenes as a major antibiotic-resistant nosocomial pathogen in Belgian hospitals

Objective: To study the epidemiology of Enterobacter aerogenes infections in Belgian hospitals and determine whether recent trends show an increase in incidence of E. aerogenes infections and antimicrobial resistance.
Methods: Data from the bloodstream infection component of the National Surveillance of Hospital Infections (October 1992 to September 1996 data in 45 hospitals) and from a retrospective study on E. aerogenes clinical isolates (1994 and 1995 data in 41 hospitals) were analyzed.
Results: E. aerogenes was recovered from clinical specimens with a mean incidence of 4.6 isolates per 10 000 patient-days and caused 0.20 bloodstream infections per 10 000 patient-days during the surveyed periods, respectively. Both rates increased significantly throughout the years. The proportion of E aerogenes within the Enterobacter genus was 35.4% in clinical isolates and 41.2% in bloodstream infections. Both proportions significantly increased over time. Incidence was not statistically different by hospital size but showed major differences between geographic regions. Resistance rates to third-generation cephalosporins and fluoroquinolones increased, and imipenem resistance emerged in several hospitals.
Conclusions: This report provides evidence of an increase in E. aerogenes infections in Belgian hospitals and documents an increase in antimicrobial resistance of E. aerogenes strains. These figures provide a baseline for further surveillance data.     

National epidemiologic surveys of Enterobacter aerogenes in Belgian hospitals from 1996 to 1998

Two national surveys were conducted to describe the incidence and prevalence of Enterobacter aerogenes in 21 Belgian hospitals in 1996 and 1997 and to characterize the genotypic diversity and the antimicrobial resistance profiles of clinical strains of E. aerogenes isolated from hospitalized patients in Belgium in 1997 and 1998. Twenty-nine hospitals collected 10 isolates of E. aerogenes, which were typed by arbitrarily primed PCR (AP-PCR) using two primers and pulsed-field gel electrophoresis. MICs of 10 antimicrobial agents were determined by the agar dilution method. Beta-lactamases were detected by the double-disk diffusion test and characterized by isoelectric point. The median incidence of E. aerogenes colonization or infection increased from 3.3 per 1,000 admissions in 1996 to 4.2 per 1000 admissions in the first half of 1997 (P < 0.01). E. aerogenes strains (n = 260) clustered in 25 AP-PCR types. Two major types, BE1 and BE2, included 36 and 38% of strains and were found in 21 and 25 hospitals, respectively. The BE1 type was indistinguishable from a previously described epidemic strain in France. Half of the strains produced an extended-spectrum beta-lactamase, either TEM-24 (in 86% of the strains) or TEM-3 (in 14% of the strains). Over 75% of the isolates were resistant to ceftazidime, piperacillin-tazobactam, and ciprofloxacin. Over 90% of the strains were susceptible to cefepime, carbapenems, and aminoglycosides. In conclusion, these data suggest a nationwide dissemination of two epidemic multiresistant E. aerogenes strains in Belgian hospitals. TEM-24 beta-lactamase was frequently harbored by one of these epidemic strains, which appeared to be genotypically related to a TEM-24-producing epidemic strain from France, suggesting international dissemination.     

Epidemiological study of an outbreak due to multidrug-resistant Enterobacter aerogenes in a medical intensive care unit.

In 1993, 63 isolates of Enterobacter aerogenes were collected from 41 patients in a medical intensive care unit (ICU). During the same period, only 46 isolates from 32 patients were collected in the rest of the hospital. All isolates were analyzed by antibiotic resistance phenotype, and 77 representative isolates were differentiated by plasmid restriction analysis, ribotyping, and arbitrarily primed (AP)-PCR. The extended-spectrum beta-lactamases produced by 22 strains were characterized by determination of their isoelectric points and by hybridization of plasmid DNA with specific probes. The isolates were divided into 25 antibiotic resistance phenotypes, either susceptible (group I) or resistant (group II) to aminoglycosides, and exhibited three phenotypes of resistance to beta-lactams: chromosomally derepressed cephalosporinase alone or associated with either extended-spectrum beta-lactamases (mainly of the SHV-4 type) or imipenem resistance. The results of the tests divided the 77 representative isolates (group I, n = 21; group II, n = 56) into 15 plasmid profiles, 14 ribotypes, and 15 AP-PCR patterns. Although the resistant isolates (group II) exhibited different plasmid profiles, ribotyping and AP-PCR analysis demonstrated an identical chromosomal pattern, indicating an epidemiological relatedness. They were mainly found in the medical ICU and occasionally in other units. The susceptible strains (group I) had various and distinct markers and were mainly isolated in units other than the medical ICU. In conclusion, the presence of a nosocomial outbreak in an ICU and the spread of a multidrug-resistant epidemic strain throughout the hospital was confirmed. Ribotyping and AP-PCR represent discriminatory tools for the investigation of nosocomial outbreaks caused by E. aerogenes.     

Molecular Epidemiology of Recent Belgian Isolates of Neisseria meningitidis Serogroup B

In Belgium an increase in the incidence of meningococcal disease has been noted since the early 1990s. Four hundred twenty clinical strains isolated during the period from 1990 to 1995, along with a set of 30 European reference strains, and 20 Dutch isolates were examined by random-primer and repetitive-motif-based PCR. A subset was investigated by multilocus enzyme electrophoresis and pulsed-field gel electrophoresis. The data were compared with results obtained by serotyping (M. Van Looveren, F. Carion, P. Vandamme, and H. Goossens, Clin. Microbiol. Infect. 4:224–228, 1998). Both phenotypic and molecular epidemiological data suggest that the lineage III of Neisseria meningitidis, first encountered in The Netherlands in about 1980, has been introduced in Belgium. The epidemic clone, as defined by oligonucleotide D8635-primed PCR, encompasses mainly phenotypes B:4:P1.4 and B:nontypeable:P1.4, but strains with several other phenotypes were also encountered. Therefore, serotyping alone would underestimate the prevalence of the epidemic clone.     

Fimbrial and non-fimbrial haemagglutinins in Enterobacter aerogenes

Ten strains of Enterobacter aerogenes were examined for their ability to produce haemagglutinins and fimbriae. Nine strains formed a mannose-sensitive (MS) haemagglutinin associated with thin (4 nm) non-channelled fimbriae. These thin fimbriae of E. aerogenes were antigenically different from the thin fimbriae of other fimbriate strains of Enterobacter and Klebsiella and probably represent a new kind of fimbria not previously described in Enterobacteriaceae. Eight of these same nine strains also formed a non-fimbrial mannose-resistant, proteus-like (MR/P) haemagglutinin. The formation of thin fimbriae associated with MS haemagglutinin and of non-fimbrial MR/P haemagglutinin are properties not associated with other strains of Enterobacter and Klebsiella. E. aerogenes strain NCIB11460 was unusual among the strains examined in this series in that it alone produced mannose-resistant, Klebsiella-like (MR/K) haemagglutinin and type-3 fimbriae which, as judged by immunoelectronmicroscopy, were antigenically like those of type-3 fimbriate Klebsiella strains. The identifying characters of this exceptional strain of E. aerogenes are discussed in detail. All ten strains also produced thick fimbriae which by immunoelectronmicroscopy behaved like the type-1 fimbriae of Klebsiella strains. However, correlation between their presence and the production of MS haemagglutinin in E. aerogenes was not established. The findings are discussed in the light of the present difficult taxonomic status of E. aerogenes within the tribe Klebsielleae.     

Molecular and Epidemiological Characterization of Vaginal Saccharomyces cerevisiae Isolates

Although vaginitis caused by Saccharomyces cerevisiae is extremely rare, in recent years we have experienced an increasing frequency of S. cerevisiae isolation from the vaginas of fertile-age women. In order to investigate the epidemiology of these vaginal infections, a total of 40 isolates of S. cerevisiae derived from symptomatic and asymptomatic women were characterized by two DNA typing approaches, named ribosomal DNA (rDNA) hybridization and Ty917 hybridization, based on the Southern blotting technique. After transfer, the polymorphic DNA restriction fragments were hybridized with the entire repeat of S. cerevisiae rDNA for one method and with the entire sequence of the Ty917 retrotransposon for the other. After elaboration with computer-assisted analysis, the results of each method showed that Ty917 hybridization is endowed with a discriminatory power higher than that of rDNA hybridization. With the Ty917 hybridization method, all of the S. cerevisiae isolates tested appeared very heterogeneous, with the exception of those collected from individual patients with recurrent vaginitis. This allowed us to exclude a possible common source of infection while the high relatedness among S. cerevisiae sequential isolates from recurrent-vaginitis patients could suggest a pattern of relapse rather than frequent reinfection.     

Outbreak of TEM-24-producing Enterobacter aerogenes in a Spanish hospital

Organisms encoding multidrug resistance genes are becoming increasingly prevalent. During a 2-month period (December, 2000, to January, 2001), 83 consecutive isolates of Enterobacter spp. were collected in our microbiology department. Antibiotic susceptibility was determined using the Vitek II automatic system. We selected strains with decreased susceptibility to extended-spectrum cephalosporins. The double-disk potentiation test was positive in 10 of these strains, indicating the presence of extended-spectrum beta-lactamases (ESBLs). Polymerase chain reaction (PCR), isoelectric focusing (IEF), and sequencing identified TEM 24 beta-lactamase in the 10 selected E. aerogenes. Random amplification of polymorphic DNA (RAPD-PCR) revealed the same clonal origin for all the strains tested and strongly suggest an outbreak of multidrug-resistant E. aerogenes. To follow up the trends in ESBLs-producing Enterobacter infections in the hospital over time, we repeated the study 1 year later (December, 2001, to February, 2002). Only three ESBLs-producing Enterobacter were found. All of them corresponded to the previously characterized clone.     

Detection of extended-spectrum beta-lactamases in clinical isolates of Enterobacter cloacae and Enterobacter aerogenes

The aim of the present study was to investigate the frequency of extended-spectrum beta-lactamases (ESBLs) in a consecutive collection of clinical isolates of Enterobacter spp. The abilities of various screening methods to detect ESBLs in enterobacters were simultaneously tested. Among the 68 consecutive isolates (56 Enterobacter cloacae and 12 Enterobacter aerogenes isolates) that were analyzed for beta-lactamase content, 21 (25 and 58%, respectively) possessed transferable ESBLs with pIs of 8.2 and phenotypic characteristics of SHV-type enzymes, 8 (14.3%) of the E. cloacae isolates produced a previously nondescribed, clavulanate-susceptible ESBL that exhibited a pI of 6.9 and that conferred a ceftazidime resistance phenotype on Escherichia coli transconjugants, and 2 E. cloacae isolates produced both of these enzymes. Among the total of 31 isolates that were considered ESBL producers, the Vitek ESBL detection test was positive for 2 (6.5%) strains, and the conventional double-disk synergy test (DDST) with amoxicillin-clavulanate and with expanded-spectrum cephalosporins and aztreonam was positive for 5 (16%) strains. Modifications of the DDST consisting of closer application of the disks (at 20 instead of 30 mm), the use of cefepime, and the use of both modifications increased the sensitivity of this test to 71, 61, and 90%, respectively. Of the 37 isolates for which isoelectric focusing failed to determine ESBLs, the Vitek test was false positive for 1 isolate and the various forms of DDSTs were false-positive for 3 isolates.     

Most Enterobacter aerogenes strains in France belong to a prevalent clone

The aim of this study was to determine the distribution in France of the Enterobacter aerogenes prevalent clone isolated in the hospitals of the Marseille area (A. Davin-Regli, D. Monnet, P. Saux, C. Bosi, R. Charrel, A. Barthelemy, and C. Bollet, J. Clin. Microbiol. 34:1474-1480, 1996). A total of 123 E. aerogenes isolates were collected from 23 hospital laboratories and analyzed by random amplification of polymorphic DNA and enterobacterial repetitive intergenic consensus-PCR to determine their epidemiological relatedness. Molecular typing revealed that 21 of the 23 laboratories had isolated this prevalent clone harboring the plasmid encoding for extended-spectrum beta-lactamase of the TEM-24 type. Most isolates were susceptible only to imipenem and gentamicin. Their dissemination seems to be clonal and was probably the result of the general use of broad-spectrum cephalosporins and quinolones. Four isolates showed an alteration of their outer membrane proteins, causing decrease of susceptibility to third-generation cephalosporins and imipenem and leading to the critical situation of having no alternative therapeutic. The large dissemination of the E. aerogenes prevalent clone probably results from its good adaptation to the antibiotics administered in France and the hospital environment, particularly in intensive care units.     

Molecular epidemiology of Enterobacter aerogenes acquisition: one-year prospective study in two intensive care units.

To evaluate the respective contributions of patient-to-patient transmission and endogenous acquisition of Enterobacter aerogenes isolates, we conducted a prospective epidemiologic study in two intensive care units (ICUs) between May 1994 and April 1995. We collected a total of 185 E. aerogenes isolates: 130 from 51 patients in a surgical ICU (SICU), 45 from 26 patients in a medical ICU (MICU), and 10 from the environments in these two ICUs. All isolates were typed by random amplification of polymorphic DNA and enterobacterial repetitive intergenic consensus PCR. Among the 175 clinical isolate, we observed 40 different profiles by random amplification of polymorphic DNA and 36 different profiles by enterobacterial repetitive intergenic consensus PCR. We identified a ubiquitous and prevalent clone, corresponding to 58% of SICU and 41% of MICU clinical isolates. Three epidemiologically related strains were specific to each ICU and represented 17% of SICU and 24% of MICU clinical isolates; unique type strains represented 17 and 29% of SICU and MICU clinical isolates, respectively, and E. aerogenes strains which were spread to a limited degree and which were isolated less than five times during the 1-year study period represented 8 and 6% of SICU and MICU clinical isolates, respectively. Our results show that E. aerogenes is acquired in the ICU in three different ways: patient-to-patient spread of a prevalent or an epidemiologically related strain, acquisition de novo of a strain from patients' own flora, and acquisition of a nonendemic strain followed by occasional patient-to-patient transmission. The findings point out the importance of patient-to-patient transmission in E. aerogenes acquisition and suggest that changes in E. aerogenes ecology in the hospital have taken place during the past decade.     

Detection of resistance due to inducible beta-lactamase in Enterobacter aerogenes and Enterobacter cloacae.

Thirty-six of 36 strains of Enterobacter cloacae and E. aerogenes with inducible beta-lactamase developed resistance when cefoxitin (inducer) was added to cefuroxime disks. Constitutive beta-lactamase producers (n = 23) were all resistant to cefuroxime. Cefuroxime resistance correlated with the amount of induced or constitutive beta-lactamase. Cefuroxime was a better indicator of induced resistance than cefamandole, cefazolin, cephalothin, ceftriaxone, cefotaxime, ticarcillin with or without clavulanic acid, or cefotetan. Induction by addition of cefoxitin to disks occasionally reduced zone sizes but not enough to change interpretations for ceftazidime, ceftizoxime, aztreonam, cefoperazone with or without sulbactam, and piperacillin with or without tazobactam. Most enterobacters were resistant to cefmetazole. The cefoxitin inducer-cefuroxime indicator method can be used in routine clinical laboratories to detect latent resistance due to chromosomally mediated inducible beta-lactamase in enterobacters.     

Molecular Mechanisms of Carbapenem Resistance in Enterobacter cloacae Clinical Isolates from Korea and Clinical Outcome

We investigated the molecular mechanisms of carbapenem resistance in clinical isolates of Enterobacter cloacae and their clinical characteristics. Nonreplicable E. cloacae isolates were recovered from six cancer patients and one patient with liver cirrhosis at a tertiary-care hospital in Korea between 2002 and 2009. Two patients who were considered to have a true infection caused by these microorganisms have died. All isolates produced AmpC β-lactamases, including ACT-1, ACT-2, MIR-3 and DHA-1, and CTX-M- or SHV-type extended-spectrum β-lactamase. Two isolates produced plasmid-borne VIM-2 carbapenemase. All probes specific for bla(AmpC) genes hybridized with I-CeuI chromosomal fragments were also recognized by a probe specific for 16S rDNA, suggesting a chromosomal location. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that a major outer membrane protein, OmpF, was absent in all isolates. PFGE of XbaI-digested DNA were considered to be unrelated. The results of our study suggest that the chromosomal AmpC β-lactamase with impermeability in E. cloacae clinical isolates implicated in reduced carbapenem susceptibility. Although carbapenem-resistant E. cloacae isolates were isolated in a few patients in our study, the clinical outcomes were grave. Therefore, the patients colonized or infected by carbapenem-resistant E. cloacae isolates should gain attention of antibiotic therapy.     

Detection of SHV-Type Extended-Spectrum Beta-Lactamase in Enterobacter Isolates

One hundred four Enterobacter isolates were tested by standard CLSI disk diffusion methods for detecting extended-spectrum beta-lactamases (ESBLs) and with cefepime-clavulanate disk combinations. SHV-12 was produced by 8.7% of isolates. The cefepime-clavulanate combination provided 88% sensitivity and 91% specificity for the detection of SHV-12 ESBL.Detection of extended-spectrum beta-lactamase (ESBL) production in Enterobacter spp. has not been undertaken by most clinical laboratories due to a lack of recommendations from the Clinical and Laboratory Standards Institute (CLSI) and potential interference in test interpretation from high-level production of an AmpC beta-lactamase (5). This inability to readily identify ESBLs in pathogens that potentially coproduce AmpC beta-lactamase and an ESBL presents a concern for providers considering cefepime therapy for these patients, since there is an inoculum effect with ESBLs that affects all cephalosporins (2, 6, 7, 13, 16). Detection of an ESBL could lead to selection of a carbapenem for therapy rather than a cephalosporin like cefepime due to a potentially poorer clinical response (4, 11, 14, 17), whereas Enterobacter isolates that produce only AmpC have been treated reliably with cefepime (12).Enterobacter isolates recovered from blood cultures at the University Health System in San Antonio, TX, between 1 October 2004 and 31 December 2007 were examined in this study. These represented the first isolates from each patient and were nonrepetitive, with the exception of one patient, from whom two different Enterobacter spp. were identified. Initial identification and susceptibility testing were performed using a Vitek 2 instrument (GN13 cards; bioMerieux, Durham, NC) and/or standard CLSI disk diffusion methodologies (3). All isolates underwent ESBL phenotypic confirmatory disk testing utilizing the cefotaxime- and ceftazidime-clavulanate combinations as described by CLSI for Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca, and Proteus mirabilis (3). In addition, cefepime disks (30 μg) were tested and zone diameters were recorded in a comparison with cefepime disks to which 10 μg of clavulanate was added in an attempt to improve the ability to detect ESBL production in organisms producing native AmpC beta-lactamase. E. coli ATCC 25922, E. coli ATCC 35218, and K. pneumoniae ATCC 700603 were included with each day''s tests for quality control purposes. Zone diameters were recorded for the antimicrobial agent combinations with each isolate. Any isolate with a zone diameter that increased by at least 3 mm (the minimum zone difference that we felt could be reliably measured) with the addition of clavulanate for any of the three cephalosporins or for which no zone of inhibition was seen around any of the three cephalosporin disks was considered a possible ESBL producer and was subjected to further examination.Using previously described methods, those isolates meeting the screening criteria and a random sampling of 15 isolates not meeting those criteria (control group) were further examined by PCR and gene sequencing to detect possible ESBLs of the three main families, i.e., CTX-M, SHV, and TEM (10). Isoelectric focusing was performed on selected isolates to confirm that all enzymes were detected.One hundred four Enterobacter isolates were examined. Enterobacter cloacae represented 81/104 (77.9%) of those tested, with the remaining 23 (22.1%) being Enterobacter aerogenes. Sixteen percent (n = 17) of isolates were identified as either having a zone diameter change of ≥3 mm or greater or no zone of inhibition around any of the three cephalosporin disks (study group). Ten isolates in the study group had a zone diameter change of ≥5 mm for one or more of the three cephalosporins. Based upon PCR and sequencing, nine (8.7%) of the isolates harbored an ESBL; all harbored a single enzyme, SHV-12. Eight of the nine (89%) SHV-12-producing strains were E. cloacae. No CTX-M or TEM ESBLs were identified in the study group. In addition, no isolates in the control group were found to have an ESBL following molecular characterization.Sensitivity and specificity were evaluated for each of the disk diffusion tests at each of the zone diameter changes (Table ​(Table1).1). Sensitivity analyses revealed that both ceftazidime and cefepime exhibited excellent sensitivity for detection of SHV-12 if a zone diameter change of >3 mm was employed as opposed to the usual ≥5-mm change advocated by the CLSI for other organisms. Specificity was highest overall in the cefotaxime arm (100%), but poor sensitivity (66%) limits the applicability of this substrate for the detection of ESBL in Enterobacter spp. The cefepime-clavulanate combination at a zone diameter change of ≥3 mm exhibited the highest combination of sensitivity (88%) and specificity (91%) of all combinations. Unexpectedly, tests utilizing ceftazidime and ceftazidime-clavulanate also provided very good results, especially if a zone diameter change of ≥3 mm was used (sensitivity of 88%; specificity of 82%).

TABLE 1.

Sensitivity and specificity of ESBL detection based upon disk diffusion zone diameter changes with addition of clavulanate^a

Molecular epidemiology of an outbreak of multidrug-resistant Enterobacter aerogenes infections and in vivo emergence of imipenem resistance.

Molecular typing was used to investigate an outbreak of infection caused by multidrug-resistant Enterobacter aerogenes (MREA) susceptible only to gentamicin and imipenem in an intensive care unit (ICU). Over a 9-month period, ciprofloxacin-resistant E. aerogenes isolates were isolated from 34 patients, or 4.1% of ICU admissions, compared with a baseline rate of 0.1% in the previous period (P < 0.001). Infection developed in 15 (44%) patients. In vivo emergence of imipenem resistance (MIC, 32 micrograms/ml) of organisms causing deep-seated infection was observed in two (13%) of these patients following prolonged therapy with imipenem and gentamicin. Arbitrarily primed PCR (AP-PCR) analysis with ERIC1R and ERIC2 primers and pulsed-field gel electrophoresis (PFGE) analysis of XbaI macrorestriction patterns concordantly showed that outbreak-associated MREA isolates were clonally related and distinct from epidemiologically unrelated strains. AP-PCR and PFGE showed discrimination indices of 0.88 and 0.98, respectively. Space-time clustering of cases within units suggests that the epidemic-related MREA isolates were transmitted on the hands of the health care personnel. A case-control study and repeated environmental culture surveys failed to identify a common source or procedure associated with transmission. In spite of the early implementation of isolation measures, the incidence of MREA colonization remained stable until all colonized patients were discharged. This study confirms the usefulness of AP-PCR and PFGE analyses for the epidemiological study of E. aerogenes and underscores the difficulty of controlling the spread of multiresistant clones of this organism in the ICU setting. The emergence of imipenem resistance represents a threat because virtually no therapeutic option is available for such strains.     

Discriminatory Power of Three Typing Techniques in Determining Relatedness of Nosocomial Klebsiella pneumoniae Isolates from a Tertiary Hospital in India

Purpose: The purpose of this study was to evaluate the discriminatory power of two DNA-based technique and a protein-based technique for the typing of nosocomial isolates of Klebsiella pneumoniae. A second objective was to determine the antimicrobial susceptibility pattern and characterise the presence of genes encoding extended-spectrum beta-lactamases (ESBLs) and carbapenemases. Materials and Methods: Forty-six K. pneumoniae isolates from patients with bloodstream infections at a tertiary care hospital in India between December 2014 and December 2015 were studied. All isolates were typed using enterobacterial repetitive intergenic consensus sequence-polymerase chain reaction (ERIC-PCR), randomly amplified polymorphic DNA (RAPD) analysis and matrix-assisted laser desorption ionisation time-of-flight (MALDI-TOF) mass spectrometry. Antimicrobial susceptibility profiles and ESBLs were detected using the BD Phoenix system. The types of ESBL and carbapenemase genes present were detected using PCR. Results: Isolates were subtyped into 31, 30 and 33 distinct genotypes by ERIC-PCR, RAPD and MALDI-TOF, respectively. Several isolates displaying identical DNA fingerprints were binned into different branches based on their proteomic fingerprint. Antimicrobial susceptibility tests revealed that 33/46 strains were multidrug resistant (MDR); a majority of the strains (83%) were sensitive to colistin. PCR-based analysis demonstrated 19 strains to harbour two or more ESBL and carbapenemase genes. Conclusion: ERIC-PCR was the most reproducible method for typing K. pneumoniae isolates and could not be substituted by MALDI-TOF for clonality analysis. A high degree of genetic diversity and the presence of MDR genes highlight the challenges in treating K. pneumoniae-associated infections.