Resistance of anaerobic bacteria. Can we find any clinical impact? Szeged ESCMID School 2005

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1 Resistance of anaerobic bacteria Can we find any clinical impact? Szeged ESCMID School 2005 L. Dubreuil Faculté de Pharmacie Université de Lille II, France

2 Antibiotic resistance among anaerobes Intrinsic resistance all anaerobes aminoglycosides, quinolones, fosfomycin,trimethoprim,aztreonam species -dependant : metronidazole : Propionibacterium & Actinomyces rifampicin : F. necrophorum, F. mortiferum cephalosporins : C. difficile cefotetan & vancomycin : C. innocuum Bacteroides fragilis group : C1G, aminopenicillins Fusobacterium : macrolides Acquired resistance

3 Antibiotic resistance among anaerobes Acquired resistance : ß-lactams : ß -lactamase Clostridia (butyricum, + RIC group) Prevotella, Fusobacterium B. fragilis gene + promotor cfia carbapenemase, cfxa Hyperproduction of the chromosomal enzyme lack of porin & PBP modifications

4 Antibiotic resistance among anaerobes Acquired resistance : MLSb erm genes clindamycin Metronidazole nim genes Fluroquinolones gyrase, topoisomerase mutations resistance to Moxifloxacin Chloramphenicol cat genes

5 The situation in Europe Gram positive cocci susceptible penicillins > cephalosporins glycopeptides, linezolid, rifampicin acquired resistance clindamycin > 20% metronidazole < 5% variable fluoroquinolones

6 The situation in Europe Actinomyces susceptible penicillins > cephalosporins glycopeptides, linezolid, rifampicin acquired resistance variable tetracycline macrolides (rare) fluoroquinolones

7 The situation in Europe Propionibacterium susceptible penicillins > cephalosporins fluoroquinolones glycopeptides, linezolid, rifampicin acquired resistance tetracyclin macrolides & clindamycin increasing

8 The situation in Europe C. perfringens susceptible penicillins > cephalosporins, cefoxitin metronidazole, glycopeptides, linezolid, rifampicin most fluoroquinolones acquired resistance tetracyclins macrolides & clindamycin rare One strain resistant to metronidazole Faris & Poxton 1999

9 The situation in Europe C. difficile susceptible acquired resistance penicillins, metronidazole, glycopeptides, fusidic acid, bacitracin tetracyclins, chloramphenicol macrolides & clindamycin > 60% emerging? Vancomycin & metronidazole

10 The situation in Europe Other clostridia (with exception), susceptible penicillins > cephalosporins glycopeptides linezolid, metronidazole acquired resistance tetracyclins macrolides & clindamycin cefoxitin & cefotetan chloramphenicol glycopettides :C. boltae,c. hathewayi (Van B2)

11 The situation in Europe clostridia RIC group C. butyricum : penicillinase inhibited by clavulanic acid C. clostridioforme broad cephalosporinase low-level resistance to teicoplanin, daptomycin, ramoplanin C. ramosum broad cephalosporinase not inhibited by clavulanic acid low-level resistance to vancomycin, linezolid, daptomycin C. innocuum intrinsic resistance to cefoxitin and cefotetan low-level resistance to vancomycin & daptomycin

12 And now? Gram positive cocci Non-sporulated gram positive bacilli Clostridia No major clinical problems except for individual patients low rate of antibiotic diffusion (brain, bone,) be aware of RIC group glycopeptide resistance in clostridia.

13 What about gram negative anaerobes? Prevotella 2/3 ß-lactamase production + acquired resistance clindamycin 5% metronidazole rare variable fluoroquinolones Porphyromonas Fusobacterium penicillinase < 10%

14 Les mousquetaires anaérobies des infections pulmonaires et O.R.L QuickTime et un décompresseur TIFF (non compressé) sont requis pour visualiser cette image.

15 Prevotella : MIC 50/90% ß-lactamase - ß-lactamase + Amoxicillin 0,12 0,25 8 >64 Amox +clavu 0,06 0,06 0,06 2 Cefalotin 0, >64 Cefuroxime 0, >64 Cefixime 0, >64 Cefpodoxime 0,12 0,5 4 >64 Ceftriaxone 0,12 0,5 4 >64

16 Prevotella : MIC distribution Nb of strains Amoxycillin MIC in mg/l

17 Prevotella : distribution des CMI Nb of strains Cephalotin ß-lac + ß -lac - MIC in mg/l

18 Prevotella : distribution des CMI 14 Nb of strains 12 Cefuroxime >128 ß-lac + ß lac - MIC in mg/l

19 Nb of strains 14 Prevotella : distribution des CMI 12 Cefpodoxime ß -lac - ß-lac + MIC in mg/l

20 Antibiotic susceptibility in Porphyromonas Antibiotic MIC range MIC 50% MIC90% Amoxicillin 0,03-0,5 0,5 0,5 Co-amoxiclav 0,03-0,25 0,25 0,25 Cefotaxime 0, Clindamycin 0,03-0,25 0,06 0,25 Metronidazole 0,03-0,25 0,125 0,25 Roxithromycin 0,25 Pristinamycin 0,25

21 FQ susceptibility of Prevotella & Fusobacterium Antibiotic Prevotella Fusobacterium MIC 50% 90% 50% 90% Ciprofloxacin Ofloxacin Levofloxacin Moxifloxacin 0,12 0,5 0,12 1 Gatifloxacin 0,25 2 0,5 4 Trovafloxacin 1 2 0,25 0.5

22 Anaerobic lung infections. High rate of penicillin failures associated with penicillin-resistant Prevotella melaninogenica 10/47 resistant strains 5 patients received benzyl-penicillin 2 M every 4 hours all failed Failure penicillin 8/18 vs 1/19 clindamycin Gudiol Arch inter Med :2525

23 Role of ß-lactamases from gram neg anaerobes Nord-Brook ß-lactamases excreted by Prevotella or Fusobacterium caused clinical failures when patients were treated by penicillins otitis - sinusitis-dental abcess-lung abcess-recurrent tonsillitis

24 Anaerobic infections Bacteroides fragilis group + Clostridium : intra-abdominal gyneco-obstetrics, biliary infections Perforated appendicitis Decubitus ulcers

25 Last but not least the B. fragilis group Chromosomal cep A ß-lactamase AMX + C1G+ C3G+C4G + overproduction TIC + PIP + lack of porin AMC, TTC, PTZ? carbapenemase All ß-lactams MLSb Clindamycin (20-40%) nim genes Nitro-imidazole

26 AMX TIC PIP CTX IMP MTZ CFT CFX CTT ERY CLN AMC TCC PTZ TE CM

27 Resistance to the combinations of ß- lactams and ß-lactamase inhibitors IS 1224 upstream the cep A gene increases the production of the chromosomal cephalosporinase Rogers et al.j Bacteriol 1994;176: High level production of the cephalosporinase alone or associated with modifications in the permeability barrier (defect of porin)

28 Phenotypes of resistance among imipenemsusceptible strains of the B. fragilis group Antibiotic wild hyperproduction of ß-lactamase or/and lack type of porin or silent carbapenemase % (72) (19) (6) (2) (1) Ticarcillin S R R R R Coamoxiclav S S S/I I/R R Ticar + clavu S S S S I/R Pipera+tazo S S S S I Cefotetan S/I I/R R R R

29 Figure 1 : Antibiotic resistance rates among the B. fragilis group (256 strains) in Antibiotic resistance rates (%) 27, ,8 1,9 1,9 4,3 6,2 0 Metronidazole Imipenem Ticar+ clavu Pipéra +tazo Co-amoxclav Cefoxitin Ticarcillin Clindamycin

30 Activity of fluoroquinolones against the B. fragilis group (130 strains) GAR MOX LEV CIP CIP LEV MOX GAR

31 Antibiotic resistance rates (%) - B. fragilis group Are antibiotic resistance rates increasing? MTR AMC CLN MTR 0,4 1,9 4,7 4,3 AMC 4 3,8 5,6 4,3 CLN

32 Metronidazole resistance nim on mobilisable plasmids nim A B.vulgatus nim C B. thetaiotaomicron nim D B. fragilis nim B chromosomal B. fragilis, P. acnes, A. odontolyticus, C. bifermentans nim A in Prevotella bivia nim G B. fragilis

33 B. fragilis S or Intermediate to metronidazole

34 B. fragilis metronidazole-r

35

36 Metronidazole resistance Gal & Brazier, JAC 2004,54: / 206 isolates were found to possess nim genes and these had MICs of MTZ from 1.5 to >256 mg/l with 11.6% above the therapeutic breakpoint of 16 mg/l Disc diffusion mm test on FAA with a 5 µg MTZ disc. 70% showed reduced zone of susceptibility or no zone 30% with no reduced zone MIC 1.5 to 4 mg/l No zone for 7 strains without nim gene.

37 Results (2) Bacteroides fragilis group (PCR-RFLP) Strain N 17: nimb 22: nime 23: nimd 29: nimd 31: nimb 39: nima Strain N 40: nima (sequencing) Veillonella sp. Strain N 18 : nime (sequencing) M ND E c o R V F o k I H i n f I

38 Results (3) MTZ /R MTZ /R MTZ /I 2 copies of nima gene in the genome of: - MTZ Resistant strain (MIC = 64 mg/l) - MTZ intermediate strain (MIC = 16 mg/l) nima SfiI nima EcoRI nima EcoRI

39 Clinical significance of intermediate or resistant metronidazole clostridia? Elsaghier, Brazier et al. JAC 2003 Failure of treatment due to Bacteroides fragilis with reduced susceptibility to metronidazole. Pelvic collections grew mixed coliforms susceptible to cefuroxime Patient treated by Cefuroxime +metronidazole +gentamicin. Pyrexia after four days of Tt. WBC 16000/mm 3 B. fragilis MTR-R cultured from blood cultures (disk diffusion) MIC by E test 6 mg/l.

40 Metronidazole resistance in France French resistant strains MTZ-R Prevotella buccae et 3 souches de P. loescheii CMI = 16 mg/l B. fragilis MIC = 64 mg/l H. Marchandin et al. Anaerobes 2002;8:137 Veillonella nim E in a metronidazole-susceptible Veillonella sp. strain MIC = 4 mg/l H. Marchandin, Dubreuil, AAC :3207

41 Bacteremia caused by Prevotella sp. with reduced susceptibility to metronidazole Mory et al.ecc Paris december old patient with sepsis Cefotaxime (3g)+ ofloxacin (400mg) E. coli S + Streptococcus anginosus S Patient pyrexial new blood cultures Day 7 Day 16 Teicoplanin 400mg and metronidazole 500mg tid added Prevotella AMX, CTX, OFL-R, MTR S but colonies appearing later in the inhibition zone MIC 64 mg/l. persistance of fever Piperacillin + tazobactam 12g + Cipro 800 mg. Apyrexia in 48h

42 Metronidazole resistance B. fragilis & B. ovatus from appendicetomy MIC >32 mg/l : failure in Koweit Rotimi et al. Clin Microbiol Infect 1999 ; 5: B. fragilis MIC =256 in New Delhi with clinical failure B. fragilis MIC >32 mg/l in Seattle Chauldry, Emerging Infect Dis 2001,7, Shapiro et al. J Clin Microbiol 2004 ;42: B. fragilis in Hungary (Nagy et al.), Poland (Wojcik) Prevotella loescheii MIC 12 mg/l subdural empyema in Cardiff Sandoe JAC 2001;47:

43 Metronidazole resistance C. difficile MIC =16 mg/l in Hong Kong, Madrid and Cardiff Wong et al.diagn Microbiol Infect Dis 1999 ;34:1-6 Pelaez AAC 2002,46: Brazier et al. JAC 2001;48: Equine isolates in Sacramento MIC = 32 mg/l Jang et al. Clin Infect Dis 1997, S Finegoldia magna MIC >128 mg/l Cape Town Theron et al. JAC 2004; 54 : C. perfringens in Edinburgh MIC >32 mg/l Faris et al. J Infect 1999,2:

44 In vivo veritas Many variables in addition to in vitro susceptibility testing Site of infection Surgical procedures Type of underlying disease Presence of other pathogens (mixed infections) Type of therapy used

45 Correlation of clinical outcomes in patients with B. fragilis group infections treated with cefoxitin Snydman et al AAC Patients in the treatment failure group were more likely to have - a longer cefoxitin dosing interval (p=0.019) -a shorter duration of cefoxitin (p = 0.051) -a longer duration of hospitalization -a higher observed maximum leucocyte count

46 Plot of clinical cure or treatment failure versus MIC and cefoxitin dosing interval MIC mg/l 64 Time above the MIC cured failed Dosing interval (h)

47 PK/PD concentration T > MIC MIC T > MIC Time

48 Antibiotic Susceptibility Testing pro or con? Wilson CID 1995 suppl 2 S251 Chow 1974 appropriate antibiotic therapy of Bacteroides bacteremia is associated with a better outcome than inappropriate therapy but Surgeons advocated (MC Namara 1993) «routine practise of obtaining cultures in patients operated on for acute and complicated appendicitis should be abandoned» «No benefit from susceptibility data» (Mosdell 1991)

49 AST pro or con in peritonitis? Mosdell only 8.8% of patients who had inadequate empirical therapy was an appropriate change in antibiotic treatment Dougherty «culture results appeared to influence antibiotic therapy for only 7% of these patients» No benefit from susceptibility data (Mosdell 1991) Worrisome disjunction between surgeon and microbiologist

50 AST pro or con in peritonitis? Worrisome disjunction between surgeon and microbiologist Berne BUT In vitro susceptibility was significantly associated with infectious postoperativc outcome «89% of patients in whom primary therapy failed had resistant strains compared with 46% in whom therapy succeeded. So... The concept persists that in patients with polymicrobial infection adequate surgical treatment and antibiotic at least cover aerobic component of the flora will suffice

51 Hopkins 1993 AST pro or con in peritonitis? Study of 175 patients with intra-abdominal infections «both aerobic and anaerobic bacteria susceptibility was statistically correlated with outcome» 26% of resistant B. fragilis from those who had an infection vs 3% those who have not Patients with resolution of the IA infection 44% of resistant isolates vs 82% if complications

52 Retrospective study of anaerobic bacteremia Blood cultures positive for anaerobes 81 patients Clinically significant bacteremia 57 patients Clinically insignificant bacteremia 24 patients Initial tt ineffective Changed to effective 32% Initial tt effective 49% 5% died 17% died Initial tt ineffective Not changed 19% 55% died Salonen CID :1413

53 Antimicrobial resistance and clinical outcome of Bacteroides bacteremia Well-designed prospective study with stratification of patients 81 patients treated with an antimicrobial agent to which the isolate was susceptible and 11 with a resistant isolate. Therapy Inactive active p= Mortality 45% 16% 0.03 Clinical failure 82% 22% Persistence 47% 12% 0.06

54 Antimicrobial resistance and clinical outcome of Bacteroides bacteremia Failure 4/6 clindamycin-resistant B. fragilis (MIC 16 mg/l) 1/13 clindamycin-susceptible B. fragilis Piperacillin 3 failures = all resistant isolates MIC 256 mg/l One cefotetan-resistant B. caccae = failure

55 Multivariate analysis of risk factors for death and clinical failure of treatment for patients with Bacteroides bacteremia Outcome, risk factor Multivariate analysis OR ( 95%CI) Death APACHE II score > (4-104) Inactive therapy (0.9-28) Clinical failure APACHE II score > (4-71) Inactive therapy (4-337) Liver disease.68 5 (1-29)

56 Prediction of patients response to therapy Specificity 97% Positive Predictive value 82% Sensitivity 63%

57 Principles of antibiotic treatment in community-acquired peritonitis To be started as soon as the diagnostic is done and surgery is decided Rapid treatment IV route Drugs may be different from those used in prophylaxis Antibiotics directed towards Enterobacteriaceae and anaerobes cause of mortality and abscesses formation Bartlett JG. Med Clin North Am. 1995;79:

58 Pathophysiology of intra-abdominal infections Role of Enterobacteriaceae and anaerobes Mortality Abscesses observed % E. coli E. faecalis B. fragilis E. coli + E. faecalis E. coli + B. fragilis E. faecalis + B. fragilis Onderdonk. Infect Immun. 1976

59 Pathophysiology of intra-abdominal infections % 100 Role of Enterobacteriaceae and anaerobes Mortality 75 Abscesses Control untreated Gentamicin Clindamycin Clindamycin + gentamicin Weinstein. JID. 1975

60 INVANZ (Ertapenem) in communauty acquired peritonitis Background relative influence of the outcome surgery 1 ICU 2 antibiotic therapy 3 Numerous identical protocols demonstrating the equivalence of antibiotics (cf. Consensus)

61 Impact of an initial adequate antibiotic treatment?

62 Community-acquired peritonitis : pronostic Success Mortality (%) Success (%) Death

63 Mortality Appropriate surgical procedure + adequate ATB 6 % Appropriate surgical procedure + inadequate ATB 71 % Inappropriate surgical procedure + adequate ATB 90 % Inappropriate surgical procedure + inadequate ATB 100 % Carlet J. L infection en réanimation. Masson Paris 1986 pp

64 Inadequate antimicrobial therapy in peritonitis Effect on mortality 92 patients patients with secondary peritonitis 65 patients (71%) received an inappropriate antibiotic therapy - initially - or in the course of therapy 94 % ofothe patients who died received an inappropriate therapy Koperna. Arch Surg 1996;131:180

65 A1 Effect of inadequate initial antibiotic therapy in peritonitis (2) Financial implications Canada ( ) 8 hospitals Initial therapy Adeqate n=383 Inadequate n=51 (14 %) Ssucces of treatment %s n=3 (0.9%) n=46 n=282 (85.2%) n=2 (3.9%) (13.9%) n= %) n=28 (54.9%) Ampi + Genta + Metro Cefoxitine Genta + Metro Cefazolin + Métro Cipro + Metro Other< 5% of cases Mean hospital cost (4 %) 14 (16 %) 9 (17 %) 6 (19 %) 6 (26 %) % 0 Adequatre n=331 Inadequate n=51 Success failure others Mean antibiotic cost Mean biochemistry cost Mean microbiology cost + 34 % % % Chabot I. et al. IDSA P 604

66 Folie 65 A1 Insert white background for graph. White fonts Admin;

67 Infections including B. fragilis? YES If efficacy against B. fragilis Most anaerobes are cured NO Consider Prevotella & Fusobacterium and the ß-lactamase production

68 Conclusion Need for : antibiotic susceptibility testing ß-lactamase production Detection of a carbapenemase Detection of resistance and decreased susceptibility to metronidazole Clindamycin empiric treatment on anaerobes not warranted