R A Corrigan and M M Raza Milton Keynes Hospital ...

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to guide therapy for imported cases of enteric fever. Imported ... Azithromycin for trea ng uncomplicated typhoid and paratyphoid fever (enteric fever). Effa EE ...
R  A  Corrigan  and  M  M  Raza    Milton  Keynes  Hospital  NHS  Founda:on  Trust,  UK   PURPOSE  

CASE  REPORT  

DISCUSSION  

  This   case   report   highlights   a   case   of   relapse   of   azithromycin  resistant  S.  paratyphi  A  bacteraemia.       It   illustrates   the   changing   suscep:bility   paEern   of   Salmonella  and  the  importance  of  suscep:bility  tes:ng   to  guide  therapy  for  imported  cases  of  enteric  fever.    

  We   report   the   case   of   a   27   year   old   gentleman   from   India  who  was  re-­‐admiNed  to  our  hospital  with  fevers.       He   had   been   admiNed   6   weeks   before   with   a   febrile   illness,  having  just  arrived  from  India  to  work  in  the  UK.   His   blood   cultures   grew   Salmonella   paratyphi   Type   A.   and  liver  func2on  was  mildly  deranged.       The  isolate  was  sensi2ve  to  ampicillin,  trimethoprim  and   third   genera2on   cephalosporins   but   resistant   to   azithromycin   and   ciprofloxacin.   Ini2ally   he   was   treated   with  IV  ceSriaxone  but  his  fever  was  slow  to  defervesce.   Subsequently   azithromycin   was   added   but   stopped   in   view   of   resistance.   His   fevers   and   CRP   normalised   and   he   went   on   to   complete   2   weeks   of   IV   ceSriaxone.   His   stool   sample   from   this   admission   was   nega2ve   for   Salmonella.         On  readmission  6  weeks  later  he  was  once  again  febrile   with   blood   cultures   growing   the   same   organism   sugges2ng   a   relapse.   He   was   commenced   on   IV   ceSriaxone   once   more   along   with   oral   co-­‐trimoxazole.   Stool   and   urine   cultures   were   once   again   nega2ve   for   Salmonella.   Of   note   abdominal   ultrasound   revealed   gallstones  although  he  had  no  abdominal  symptoms  and   liver   func2on   was   normal   on   this   admission.   His   HIV   serology   was   nega2ve   and   his   fever   resolved   within   48   hours.       This  pa2ent  was  treated  with  IV  ceSriaxone  for  2  weeks   and   oral   co-­‐trimoxazole   for   4   weeks   in   order   to   reduce   the  risk  of  carriage  in  view  of  the  gallstones.  

  Resistance  of  Salmonella  species  to  chloramphenicol,  co-­‐ trimoxazole,   and   ampicillin   (defined   as   mul2drug   resistance)   as   well   as   reduced   suscep2bility   and   resistance   to   ciprofloxacin   is   well   documented.   In   addi2on,   raised   MICs   of   azithromycin   in   rela2on   to   S.   typhi   and   paratyphi   A,   including   treatment   failure   with   azithromycin  has  been  reported3.  Escherichia  coli  may  be   a  reservoir  for  macrolide  resistant  genes  and  may  cause   azithromycin   resistance   in   Salmonella   through   plasmid   exchange5.       Current   Bri2sh   Society   for   An2microbial   Chemotherapy   (BSAC)   suscep2bility   guidelines   provide   disc   suscep2bility  guidance  for  azithromycin  for  S.  typhi  only     but   no   definite   MIC   guidance.   However   others   have   suggested  a  breakpoint  MIC  of  16  mg/liter  for  wild  type   Salmonella  isolates.  

BACKGROUND     Imported  cases  of  both  S.  typhi  and  paratyphi  con2nue   to  increase  in  the  United  Kingdom  par2cularly  from  the   Indian  subcon2nent.       Mul2drug   resistance   is   a   well-­‐recognized   problem1.   Resistance   to   fluoroquinolones   is   common   and   has   led   to  the  use  of  azithromycin  as  a  first  line  agent2.  However   no   agreed   breakpoints   for   suscep2bility   have   been   available   un2l   recently   and   there   have   been   reports   of   azithromycin  resistance3.       Relapse   of   infec2on   is   associated   with   various   risk   factors,  including  gallstones4.   Contact:   [email protected]  

  References   1.  An:microbial  suscep:bility  of  Salmonella  enterica  serovars  in  a  ter:ary  care  hospital  in  southern  India     Choudhary  A  et  al.  Indian  J  Med  Res.  Apr  2013;  137(4):  800–802.     2.   Azithromycin   for   trea:ng   uncomplicated   typhoid   and   paratyphoid   fever   (enteric   fever).   Effa   EE,   Bukirwa   H.   Cochrane  Database  Syst  Rev.  2008  Oct  8;(4).   3.   First   Report   of   Salmonella   enterica   Serotype   Paratyphi   A   Azithromycin   Resistance   Leading   to   Treatment   Failure.   Molloy  et  al.  J  Clin  Microbiol.  Dec  2010;  48(12):  4655–4657.     4.  Common  bile  duct  stones:  a  cause  of  chronic  salmonellosis.  Lai  CW  et  al.  Am  J  Gastroenterol.  1992  Sep;87(9):1198-­‐9.   5.  Escherichia  coli  as  Reservoir  for  Macrolide  Resistance  Genes   Minh  Chau  Phuc  Nguyen  et  al.  Emerg  Infect  Dis.  Oct  2009;  15(10):  1648–1650.      

CONCLUSION     PaEerns   of   Salmonella   drug   resistance   are   changing.     The  strain  in  this  case  was  mul2drug  resistant,  resistant   to  newer  an2bio2cs  but  sensi2ve  to  older  an2bio2cs.       Azithromycin   resistance   should   be   rou:nely   tested.   However,   it     does   not   always   form   part   of   commonly   used  automated  systems.       Gallstones   are   a   risk   factor   for   relapse   of   enteric   fever.   They   increase   the   risk   of   carriage   and   impair   eradica2on.  Cholecystectomy  may  be  required.