|Year : 2015 | Volume
| Issue : 2 | Page : 323-324
An interesting case of pyelonephritis due to inactive and an atypical uropathogenic Escherichia coli
KA Chopdekar, A Singh, CA Chande, SG Joshi, AS Chowdhary
Department of Microbiology, Grant Government Medical College, Sir Jamshedjee Jeejeebhoy Group of Hospitals, Byculla, Mumbai, Maharashtra, India
|Date of Submission||19-Mar-2014|
|Date of Acceptance||01-Jul-2014|
|Date of Web Publication||10-Apr-2015|
C A Chande
Department of Microbiology, Grant Government Medical College, Sir Jamshedjee Jeejeebhoy Group of Hospitals, Byculla, Mumbai, Maharashtra
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Chopdekar K A, Singh A, Chande C A, Joshi S G, Chowdhary A S. An interesting case of pyelonephritis due to inactive and an atypical uropathogenic Escherichia coli. Indian J Med Microbiol 2015;33:323-4
|How to cite this URL:|
Chopdekar K A, Singh A, Chande C A, Joshi S G, Chowdhary A S. An interesting case of pyelonephritis due to inactive and an atypical uropathogenic Escherichia coli. Indian J Med Microbiol [serial online] 2015 [cited 2019 Aug 17];33:323-4. Available from: http://www.ijmm.org/text.asp?2015/33/2/323/154899
Escherichia More Details coli is the most frequent cause of ascending infection of urinary tract accounting for nearly 75% of the infections. Uropathogenic strains of E. coli are distinguished from other members of species by the presence of specific virulence determinants like adhesins such as P and type 1 fimbriae, toxins and cytolysins like haemolysin and iron acquisition mechanisms. ,,
In our laboratory, we came across an interesting case of pyelonephritis in a pregnant woman caused by an atypical uropathogenic strain of inactive E. coli.
A 30-year-pregnant female with bilateral renal calculi with right sided hydronephrosis, hydroureter and pyonephrosis and a JJ stent in the right kidney was admitted with history of burning micturition, pain in abdomen and fever. A microscopic examination of urine revealed presence of red blood cells (RBCs), pus cells and organisms. On culture, an extremely mucoid, non-haemolytic growth was obtained on blood agar. On MacConkey agar, a non-lactose fermenting, mucoid, gram negative, motile organism grew. The organism was nitrate reducing, indole negative(-), methyl red test positive(+), citrate(-), urease(-), Triple sugar iron agar showed alkaline slant and acid butt, phenyl alanine deaminase (-), lactose(-), sucrose(-), mannitol(+), trehalose(+), rhamnose(-), raffinose(-), arabinose(+), sorbitol(+), salicin(-), dulcitol(-), adonitol(-), inositol(-), cellobiose(-), dulcitol(-), xylose(+), maltose(+), lysine(+), arginine(+), ornithine(-), melibiose(-), mannose(+) and ONPG(-).  The culture was identified as E. coli by Vitek 2 compact bacterial identification system. A similar isolate was repeatedly recovered from the patient. The isolate was sent to Central Research Institute, Kasauli, Himachal Pradesh for identification and serotyping and the isolate was confirmed as E. coli serotype 154.
Inability of the isolate to agglutinate human O blood group RBCs indicated absence of type 1 fimbriae. Patient's serum tested for the presence of antibodies to whole cell suspension showed the organism specific antibodies in high titre.
The organism was resistant to ampicillin, cotrimoxazole, norfloxacin, gentamicin, nitrofurantoin, ofloxacin, amikacin, netilmycin, ciprofloxacin, cefotaxime, ceftriaxone and meropenem and was sensitive to imipenem by Kirby Bauer Disc diffusion test interpreted as per CLSI, 2012.  Minimum inhibitory concentration of meropenem was ≥4 μg/ml determined by broth dilution test. The isolate was found to be an extended-spectrum beta-lactamase (ESBL) producer by CLSI confirmatory test, AmpC negative as detected by cefoxitin-screening test and carbapenemase negative by modified Hodge test. The mechanism of resistance to carbapenem was attributed to hyperproduction of ESBL with decreased permeability.
The identification of Enterobacteriaceae isolate from the present case was difficult due atypical biochemical reactions. The present isolate varied from the typical isolates in being nonlactose and non-sucrose fermenting, indole negative and arginine dihydrolase positive. E. coli strains identified by DNA relatedness showing biochemically atypical strains that are anaerogenic, lactose negative, indole negative and nonmotile have been reported.  Though inactive strains of E. coli are usually nonmotile, 5% strains are reported to be motile making this strain more atypical.  Arginine hydrolysis is usually found in only 17% of strains of E. coli. Other species of Escherichia, which are indole positive are arginine negative. 
The isolate lacked type 1 fimbriae and was non-haemolytic and also did not belong to the serotypes commonly involved in pyelonephritis, yet the persistent presence of the organism in the urine and high level of organism specific antibodies in the serum indicated the pathogenic role of the organism.
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