ANTIMICROBIAL SUSCEPTIBILITY TESTING ESBL-PRODUCING ENTEROBACTERIACEAE (E. coli ST131) WITH MDR ANTIBIOGRAMS

Transcription

1 (E. coli ST131) WITH MDR ANTIBIOGRAMS Sample ES-01 (2016) was a simulated urinary tract culture for organism identification and susceptibility testing using laboratories routinely applied methods. 1-6 The patient was a 27-year-old female with dysuria and a history of recurrent urinary tract infections (UTI s). The sample contained an Escherichia coli organism in pure culture having a markedly resistant antibiogram. Furthermore, for the β-lactam class (penicillins, cephalosporins, and monobactams) the susceptibility pattern was disturbing due to a resistance mechanism targeting virtually all members of this class, e.g. an extended-spectrum β-lactamase (ESBL). This sample, producing CTX-M-15 and OXA-1/30 enzymes, was distributed as an ungraded educational challenge to determine the ability of currently-used susceptibility testing products to recognize and appropriately categorize β-lactam and associated multidrug-resistances (MDR) among the Enterobacteriaceae species causing UTIs. Organism Identification Organism identification responses of E. coli (917 participants; 98.5%) and Gram-negative organism (12; 1.3%) would be considered acceptable identification performance (99.8% overall). The most common erroneously-reported identifications were Enterobacter cloacae and Morganella morganii (one response each). E. coli results were noted for the following systems/devices (% correct for > 10 responses): MicroScan (99.5%), Vitek 2 (99.3%) and manual methods (88.7%). This level of accuracy was considered excellent overall. Only two sites currently use a MALDI-TOF device; each site reported E. coli as a response. The correct identification of E. coli can be easily achieved using standard biochemical algorithms or generally by the use of automated or semi-automated systems. E. coli is a Gram-negative facultative anaerobic member of the Enterobacteriaceae family that is widely distributed in nature and has been observed in nearly every anatomical infection culture specimen in humans including urinary and respiratory tracts, wounds, skin and subcutaneous tissues and normally sterile body fluids. 7 E. coli will grow well on all general and most selective/differential agars designed for primary isolation of Gramnegative bacilli. After overnight incubation at 35 C colony morphology will most often appear as large, round, gray to white colonies and is often hemolytic on blood-containing agars, but can be nonhemolytic. 7-8 This species is oxidase-negative, displays lactose fermentation and grows well on MacConkey agar, a characteristic shared with other Enterobacteriaceae, especially Enterobacter spp. and Klebsiella spp. This species commonly produces colonies with a shiny green metallic sheen on Eosin Methylene Blue (EMB) agar. 8 The odor of E. coli is unique, allowing for a rapid high-quality preliminary identification when an indole test (i.e., spot indole-positive) is simultaneously performed. Production of indole from tryptophan is also observed with K. oxytoca, but other colonial morphology characteristics usually differentiate between these two species. Most E. coli biotypes are motile by

2 peritrichous flagella and ferment d-glucose which differentiates this species from Shigella spp., a phenotypically similar genus with nearly the same DNA-DNA hybridization and whole genome analysis when compared to E. coli. 7 This species has been easily identified using automated ID systems (Vitek 2, MicroScan, BD Phoenix, etc.). Antimicrobial Susceptibility Testing (ungraded) Participants were asked to perform antimicrobial susceptibility testing on the E. coli. This strain was selected to challenge proper identification and to determine antimicrobial coverage across numerous classes of antimicrobial agents that are active against Enterobacteriaceae. The initial reference laboratory antimicrobial susceptibility testing was conducted using standardized reference broth microdilution method, 1 and susceptibility categories were determined by applying CLSI and other recognized criteria, 3-6 where available. The reference laboratory testing reported a total of 28 agents (Table 1) that demonstrated varied activities against this strain, however the E. coli was MDR with documented susceptibility to 11 agents, including only two orally administered antimicrobials. Table 1. Listing of expected reference susceptibility testing categorical results for this E. coli (culture of urine) sent as ungraded sample ES-01 (2016). Clinical setting was a urine sample from a 27 year old female with dysuria and a history of recurrent UTI. Antimicrobials listed by susceptibility category (Reference MIC in µg/ml): a Susceptible Intermediate Resistant Amikacin (8) Doxycycline (8) Ampicillin (>32) Cefoperazone-Sulbactam (8/4) Nitrofurantoin (64) Ampicillin-Sulbactam (>32/16) Ceftazidime-Avibactam (0.5/4) Piperacillin-Tazobactam (32/4) Aztreonam (>16) Ceftolozane-Tazobactam (1/4) Cefazolin (>16) Colistin (0.12) Cefepime (>64) Doripenem ( 0.06) Ceftaroline (>32) Fosfomycin (1) Ceftazidime (>32) Imipenem ( 0.12) Ceftriaxone (>8) Meropenem (0.03) Ciprofloxacin (>4) Minocycline (2) Gentamicin (>8) Tigecycline (0.12) Levofloxacin (>4) Tetracycline (>16) Tobramycin (>8) TMP-SMX (>4/76) b a. Susceptibility categories determined by CLSI M100-S26 (2016). 3-5 b. TMP-SMX = trimethoprim-sulfamethoxazole

3 Consensus MIC categorical accuracy ranged from 89.6% (ticarcillin-clavulanate at intermediate) to 100.0% (three drugs) with four agents having reference MIC values at the intermediate plus susceptible or resistant concentrations (Table 1 and Table 2). Among those latter antimicrobials were amoxicillinclavulanate, cefoxitin, nitrofurantoin, and piperacillin-tazobactam. The disk diffusion (DD) results, though much smaller in numbers ( 33 for TMP-SMX), had an overall accuracy ranging from 0 (cefepime, ticarcillin-clavulanate) to 100.0% (21 drugs; Table 2). False-susceptible DD results were not observed, and the overall DD accuracy rate was 97.4%. The MIC method accuracy rate was similarly high at 98.4% Table 2). Table 2. Participant performance for selected agents ( 50 response by one or both tests) listed by disk agar diffusion (DD) and quantitative MIC methods for sample ES-01 (2016), an E. coli with an ESBLpattern antibiogram. Antimicrobial agent Acceptable category a No. % correct No. % correct DD MIC Amikacin Susceptible Amoxicillin-Clavulanate Intermediate - Resistant Ampicillin Resistant Ampicillin-Sulbactam Resistant Aztreonam Resistant Cefazolin Resistant Cefepime Resistant Cefotetan Susceptible Cefoxitin Susceptible-Intermediate Ceftazidime Resistant Ceftriaxone Resistant Cefuroxime Resistant Cephalothin Resistant Ciprofloxacin Resistant Ertapenem Susceptible Gentamicin Resistant Imipenem Susceptible Levofloxacin Resistant Meropenem Susceptible Nitrofurantoin Susceptible - Intermediate Piperacillin-Tazobactam Susceptible - Intermediate Tetracycline Resistant Ticarcillin-Clavulanate Intermediate Tigecycline Susceptible Tobramycin Resistant Trimethoprim Resistant TMP-SMX b Resistant a. Correct categorical interpretation was determined by the reference MIC using the MO7-A10 method, 1 and CLSI M100-S26, EUCAST, and USCAST breakpoint criteria, 3-5 where available (except tigecycline). 6 b. TMP-SMX = trimethoprim-sulfamethoxazole

4 Few drugs (11 listed in Table 1) tested as active, a susceptible reference MIC, against this urinary tract pathogen and the categorical accuracy among them ranged from 97.3% (amikacin) to 100.0% (cefotetan) for those drugs with >50 participant responses; see Table 2. Among the agents having susceptible reference test results, the carbapenems represented 72.3% of reported data for the agents doripenem, ertapenem, imipenem, and meropenem. Nearly all of the remaining susceptible category responses were for amikacin (440; 1.1% false-resistant), tigecycline (99; 1.0% false-resistant), fosfomycin (2; 0.0% falseresistant), and ceftazidime-avibactam (1; 100.0% false-resistant by DD). No results were reported for cefoperazone-sulbactam, ceftolozane-tazobactam, polymyxins (colistin or polymyxin B), or minocycline. This organisms exhibited high-level resistance to penicillins, cephalosporins, most aminoglycosides and tetracyclines, fluoroquinolones, and TMP-SMX. As noted in an earlier API ES-series critique (ES-03, 2015), Some recently approved [USA-FDA and EMA] antimicrobial combinations of a cephalosporin and a β-lactamase inhibitor appear to have wide applications against MDR Enterobacteriaceae Among these promising agents, the ceftazidimeavibactam combination reference tested at a MIC of 0.5/4 µg/ml, (i.e., susceptible). 9 The avibactam enzyme inhibitor has documented high affinity for the ESBL-type enzymes observed in this challenge strain. 11 The ceftolozane-tazobactam combination MIC was 1/4 µg/ml, also a susceptible MIC value. Tigecycline, colistin, and fosfomycin have previously demonstrated in vitro activity against some MDR enteric bacilli harboring various β-lactamases Although these drugs have been approved by the regulators, 9 routine susceptibility testing methods 22 are as yet not widely available, especially in the most used commercial systems. The most reported susceptibility testing systems to assess this ES-01 (2016) sample were MicroScan (50.1%), Vitek 2 (48.0%), and others (three; 1.9%). Finally, some participants reported susceptibility testing results that were not appropriate for the clinical infection site or organism identification. These agents were: azithromycin (3 responses), chloramphenicol (2), clarithromycin (1), clindamycin (2), daptomycin (1), linezolid (2), moxifloxacin (10), oxacillin (1), penicillin (2), and vancomycin (2). This practice, however, represented only 0.2% of submitted participant results. Beta-Lactam and Other Resistance Mechanisms of E. coli E. coli isolates are predominantly responsible for extra-intestinal infections, mainly UTI, and clinical management has become challenging due to the high prevalence of fluoroquinolone- and extendedspectrum beta-lactam (ESBL)-resistant isolates, although resistance phenotypes to other classes of drugs also occur. 23 The increased resistance rates among E. coli clinical isolates has been associated with emergence and dissemination of a single clonal group sequence type (ST) Several reports have documented the prevalence of ST131 E. coli causing infections; however, rates vary according to the

5 selection criteria applied, geography and origin of isolate (hospital vs community). 25 A recent Phase 2 clinical trial study report documented a prevalence of 19.3% of ST131 among the overall population of E. coli causing UTI. 26 This rate was similar to that reported (17%) by Johnson et al. (2010). 27 E. coli ST131 belongs to the highly virulent phylogenetic group B2, which includes both strains responsible for extra-intestinal infections and the strains most frequently isolated from the feces of asymptomatic humans. 23 Nine subgroups have been identified within group B2 and ST131 has been related to subgroup I. Also, E. coli ST131 clinical isolates are mostly associated to serotype O25:H4 and with a specific O25 type, O25b. 23 The vast majority of E. coli harbor the fimh gene, which has been explored as a typing method, and further investigations reported that H30 was associated with fluoroquinolone-resistant isolates, with the detection of an additional ESBL-producing subset (i.e., H30Rx). 28 ESBL-producing E. coli often carry blactx-m-15, with a small percentage of isolates harboring blactx-m However, ST131 is associated with blactx-m ,27 Studies have demonstrated that ST131 isolates tend to display rates of resistance phenotype to certain classes of drugs higher than non-st131 E. coli. 23 In a Phase 2 trial, 62.9% of E. coli ST131 displayed cefotaxime and/or ceftazidime MIC results of 2 g/ml and all harbored blactx-m-15. In addition, 74.3% of ST131 isolates were ciprofloxacin-resistant. 26 In contrast, 35.8% of non-st131 isolates had cefotaxime and/or ceftazidime MIC results of 2 g/ml and 85.2% and 5.6% possessed blactx-m-15 and blactx-m-14, respectively. A ciprofloxacin resistance phenotype was observed in 56.3% of non-st131 isolates. This higher rate of beta-lactam resistance among ST131 has been attributed to the dissemination of IncF family plasmids, which carry blactx-m-15. These plasmids also often carry blaoxa-30 among other resistance genes (e.g. aminoglycoside, tetracycline, trimethoprim/sulfamethoxazole determinants), as the API ES-01 sample described herein. 10,23,26 Treatment for Occurrences of E. coli in UTIs UTIs are one the most frequent infections encountered in both inpatient and outpatient settings, and represent a major source of Gram-negative bacteremia. Both Enterobacteriaceae and non-fermentative bacilli are important causes of UTI, but E. coli is by a large margin the most common pathogen causing community as well as health-care associated UTIs. Other Enterobacteriaceae species, such Proteus mirabilis, Klebsiella pneumoniae, K. oxytoca, E. cloacae, and Serratia marcescens, also represent important causes of UTI. In recurrent UTI, especially in the presence of structural abnormalities of the urinary tract, the relative frequency increases for Klebsiella spp., Proteus spp., Enterobacter spp., Pseudomonas aeruginosa and Acinetobacter spp. 29 Treatment of UTI has been the subject of many studies and guidelines as rates of antimicrobial resistance have evolved When dealing with recurrent and/or complicated UTI, common measures include

6 obtaining a urine culture, starting broad-spectrum antimicrobial coverage and then refining the drug selection after receiving susceptibility testing results. 31 The recent increase in ESBL producers among community-acquired E. coli UTIs is of great concern due to the limited orally-delivered treatment options available for these organisms. 30 Furthermore, after instrumentation and/or repeat courses of antimicrobial therapy, antimicrobial-resistant isolates might be expected. 31 The major challenge for clinicians is to combine local susceptibility patterns with the agents that are most likely to be effective. Targeted and appropriate antimicrobial therapy can significantly reduce the morbidity and mortality associated with this infection type. However, antimicrobial resistance patterns can vary substantially by geographic region or even between institutions within a region. Recommendations from the International Clinical Practice Guidelines for the treatment of acute uncomplicated cystitis and pyelonephritis in women includes nitrofurantoin (100 mg twice daily for 5 days), fosfomycin trometamol (3 grams in a single dose), TMP-SMX (160/800 mg twice daily for 3 days), fluoroquinolones in 3 day regimens, and β-lactam agents (amoxicillin-clavulanate, cefdinir, and cefopoxime-proxetil) in 3-7 day regimens. 31 However, TMP-SMX, currently available fluoroquinolones, and the β-lactam agents listed in these guidelines should not be recommended for empiric therapy of recurrent UTI in many geographic regions due to increased resistance. 32,33,35 In contrast, nitrofurantoin and fosfomycin remain reliable options for empirical treatment of UTI. 34,36 Other antimicrobial agents more recently approved for treatment of complicated UTI are ceftolozane-tazobactam and ceftazidime-avibactam. 9,14,37,38 These two β-lactamase inhibitor combinations represent valuable additions to the armamentarium for treatment of serious UTIs, especially those caused by MDR Gram-negative bacilli. References 1. CLSI. M07-A10. Methods for dilution antimicrobial susceptibility tests for bacteria that grow aerobically; approved standard. Tenth edition. Wayne, PA: Clinical and Laboratory Standards Institute; CLSI. M02-A12. Performance standards for antimicrobial disk susceptibility tests. Twelfth Edition. Wayne, PA: Clinical and Laboratory Standards Institute; CLSI. M100-S26. Performance standards for antimicrobial susceptiblity testing: 26th informational supplement. Wayne, PA: Clinical and Laboratory Standards Institute; EUCAST. Breakpoint tables for interpretation of MICs and zone diameters. Version 6.0, January European Committee on Antimicrobial Susceptibility Testing; USCAST. Breakpoint tables for interpretations of MICs and Zone Diameters, Version 1.0, June 2015; 2015.

7 6. Tygacil. Tygacil Package Insert [cited March 1, 2016]. Available from: 7. Jorgensen JH, Pfaller MA, Carroll KC, Funke G, Landry ML, Richter SS, et al. Manual of Clinical Microbiology, 11th ed. Washington, DC: ASM Press; Garcia LS, Isenberg H. Clinical Microbiology Procedures Handbook, 3rd ed. Washington, DC: ASM Press; AVYCAZ. Cincinnati, OH: Forest Pharmaceuticals; Castanheira M, Mills JC, Costello SE, Jones RN, Sader HS. Ceftazidime-avibactam activity tested against Enterobacteriaceae from United States hospitals ( ) and characterization of betalactamase producing strains. Antimicrob Agents Chemother Jun;59(6): Coleman K. Diazabicyclooctanes: a potent new class of non-β-lactam β-lactamase inhibitors. Curr Opin Microbiol Oct;14(5): Livermore DM, Mushtaq S, Warner M, Zhang J, Maharjan S, Doumith M, et al. Activities of NXL104 combinations with ceftazidime and aztreonam against carbapenemase-producing Enterobacteriaceae. Antimicrob Agents Chemother Jan;55(1): Vazquez JA, Gonzalez Patzan LD, Stricklin D, Duttaroy DD, Kreidly Z, Lipka J, et al. Efficacy and safety of ceftazidime-avibactam versus imipenem-cilastatin in the treatment of complicated urinary tract infections, including acute pyelonephritis, in hospitalized adults: results of a prospective, investigator-blinded, randomized study. Curr Med Res Opin Dec;28(12): Zhanel GG, Lawson CD, Adam H, Schweizer F, Zelenitsky S, Lagace-Wiens PR, et al. Ceftazidimeavibactam: a novel cephalosporin/β-lactamase inhibitor combination. Drugs Feb;73(2): Farrell DJ, Flamm RK, Sader HS, Jones RN. Antimicrobial activity of ceftolozane-tazobactam tested against Enterobacteriaceae and Pseudomonas aeruginosa with various resistance patterns isolated in U.S. hospitals ( ). Antimicrob Agents Chemother. 2013;57(12): Sader HS, Rhomberg PR, Farrell DJ, Jones RN. Antimicrobial activity of CXA-101, a novel cephalosporin tested in combination with tazobactam against Enterobacteriaceae, Pseudomonas aeruginosa, and Bacteroides fragilis strains having various resistance phenotypes. Antimicrob Agents Chemother May;55(5): Sader HS, Farrell DJ, Flamm RK, Jones RN. Ceftolozane/tazobactam activity tested against aerobic Gram-negative organisms isolated from intra-abdominal and urinary tract infections in European and United States hospitals (2012). J Infect Sep;69(3):

8 18. Livermore DM, Mushtaq S, Ge Y. Chequerboard titration of cephalosporin CXA-101 (FR264205) and tazobactam versus beta-lactamase-producing Enterobacteriaceae. J Antimicrob Chemother Sep;65(9): Brust K, Evans A, Plemmons R. Tigecycline in treatment of multidrug-resistant Gram-negative bacillus urinary tract infections: a systematic review. J Antimicrob Chemother Oct;69(10): Castanheira M, Sader HS, Deshpande LM, Fritsche TR, Jones RN. Antimicrobial activities of tigecycline and other broad-spectrum antimicrobials tested against serine carbapenemase- and metallo-beta-lactamase-producing Enterobacteriaceae: Report from the SENTRY Antimicrobial Surveillance Program. Antimicrob Agents Chemother Feb;52(2): Kelesidis T, Karageorgopoulos DE, Kelesidis I, Falagas ME. Tigecycline for the treatment of multidrug-resistant Enterobacteriaceae: a systematic review of the evidence from microbiological and clinical studies. J Antimicrob Chemother Nov;62(5): Jones RN, Holliday NM, Krause KM. Validation of densititre dry-form broth microdilution panels for susceptibility testing of ceftazidime-avibactam, a broad-spectrum-beta-lactamase inhibitor combination. Antimicrob Agents Chemother Aug;59(8): Nicolas-Chanoine MH, Bertrand X, Madec JY. Escherichia coli ST131, an intriguing clonal group. Clin Microbiol Rev Jul;27(3): Petty NK, Ben Zakour NL, Stanton-Cook M, Skippington E, Totsika M, Forde BM, et al. Global dissemination of a multidrug resistant Escherichia coli clone. Proc Natl Acad Sci U S A Apr 15;111(15): Rogers BA, Sidjabat HE, Paterson DL. Escherichia coli O25b-ST131: a pandemic, multiresistant, community-associated strain. J Antimicrob Chemother Jan;66(1): Mendes RE, Castanheira M, Gasink L, Stone GG, Nichols WW, Flamm RK, et al. beta-lactamase characterization of Gram-negative pathogens recovered from patients enrolled in the phase 2 trials for ceftazidime-avibactam: clinical efficacies analyzed against subsets of molecularly characterized isolates. Antimicrob Agents Chemother Dec 14;60(3): Johnson JR, Johnston B, Clabots C, Kuskowski MA, Castanheira M. Escherichia coli sequence type ST131 as the major cause of serious multidrug-resistant E. coli infections in the United States. Clin Infect Dis Aug 1;51(3): Price LB, Johnson JR, Aziz M, Clabots C, Johnston B, Tchesnokova V, et al. The epidemic of extended-spectrum-beta-lactamase-producing Escherichia coli ST131 is driven by a single highly pathogenic subclone, H30-Rx. mbio. 2013;4(6):e

9 29. Lane DR, Takhar SS. Diagnosis and management of urinary tract infection and pyelonephritis. Emergency medicine clinics of North America Aug;29(3): Briongos-Figuero LS, Gomez-Traveso T, Bachiller-Luque P, Dominguez-Gil Gonzalez M, Gomez- Nieto A, Palacios-Martin T, et al. Epidemiology, risk factors and comorbidity for urinary tract infections caused by extended-spectrum beta-lactamase (ESBL)-producing enterobacteria. Int J Clin Pract Sep;66(9): Gupta K, Hooton TM, Naber KG, Wullt B, Colgan R, Miller LG, et al. International clinical practice guidelines for the treatment of acute uncomplicated cystitis and pyelonephritis in women: A 2010 update by the Infectious Diseases Society of America and the European Society for Microbiology and Infectious Diseases. Clin Infect Dis Mar 1;52(5):e103-e Hisano M, Bruschini H, Nicodemo AC, Gomes CM, Lucon M, Srougi M. The bacterial spectrum and antimicrobial susceptibility in female recurrent urinary tract infection: How different they are from sporadic single episodes? Urology Sep;86(3): Park SH, Choi SM, Lee DG, Cho SY, Lee HJ, Choi JK, et al. Impact of extended-spectrum betalactamase production on treatment outcomes of acute pyelonephritis caused by Escherichia coli in patients without health care-associated risk factors. Antimicrob Agents Chemother Apr;59(4): Sanchez GV, Baird AM, Karlowsky JA, Master RN, Bordon JM. Nitrofurantoin retains antimicrobial activity against multidrug-resistant urinary Escherichia coli from US outpatients. J Antimicrob Chemother Dec;69(12): Sigler M, Leal JE, Bliven K, Cogdill B, Thompson A. Assessment of appropriate antibiotic prescribing for urinary tract infections in an internal medicine clinic. South Med J May;108(5): Sastry S, Clarke LG, Alrowais H, Querry AM, Shutt KA, Doi Y. Clinical appraisal of fosfomycin in the era of antimicrobial resistance. Antimicrob Agents Chemother Dec;59(12): Bush K. A resurgence of beta-lactamase inhibitor combinations effective against multidrug-resistant Gram-negative pathogens. Int J Antimicrob Agents Nov;46(5): Sader HS, Farrell DJ, Castanheira M, Flamm RK, Jones RN. Antimicrobial activity of ceftolozane/tazobactam tested against Pseudomonas aeruginosa and Enterobacteriaceae with various resistance patterns isolated in European hospitals ( ). J Antimicrob Chemother Jun 10;69(10):