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Year : 2016  |  Volume : 59  |  Issue : 3  |  Page : 420-421
Extended spectrum β-lactamase producing Shigella flexneri serotype-2 causing bacteremia in a patient with uncontrolled diabetes mellitus

1 Department of Microbiology, Christian Medical College, Vellore, Tamil Nadu, India
2 Department of Medicine, Christian Medical College, Vellore, Tamil Nadu, India

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Date of Web Publication10-Aug-2016


We report a case of Shigella flexneri serotype-2 causing bacteremia in an elderly gentleman with uncontrolled diabetes mellitus, who had no other apparent risk factors. Antibiotic susceptibility testing revealed that the organism was a multidrug resistant extended spectrum beta-lactamase producing straian, which was confirmed by molecular characterization. This rare case alerts both the clinician and microbiologist to a previously unaddressed risk factor of Shigella spp. causing bacteremia, as well as emerging resistant strains that are on the rise in immunocompromised patients.

Keywords: Bacteremia, diabetes mellitus, Shigella flexneri

How to cite this article:
Ninan MM, George TK, Balaji V, Ramya I. Extended spectrum β-lactamase producing Shigella flexneri serotype-2 causing bacteremia in a patient with uncontrolled diabetes mellitus. Indian J Pathol Microbiol 2016;59:420-1

How to cite this URL:
Ninan MM, George TK, Balaji V, Ramya I. Extended spectrum β-lactamase producing Shigella flexneri serotype-2 causing bacteremia in a patient with uncontrolled diabetes mellitus. Indian J Pathol Microbiol [serial online] 2016 [cited 2022 Sep 26];59:420-1. Available from:

   Introduction Top

Bacteremia due to Shigella spp. is infrequently reported. The risk factors described in literature are innumerous; however, diabetes mellitus is conspicuous by its absence. Diabetes mellitus was the only apparent risk factor, but for age, in this patient. In addition to being a multidrug resistant (MDR) Shigella flexneri, this isolate also was extended spectrum beta-lactamase (ESBL) producing, conferring resistance to the cephalosporins, the primary choice of treatment in this scenario.

   Case Report Top

We report a 68-year-old farmer from South India who presented with a sudden onset of giddiness, vomiting and imbalance while walking. He was a diabetic and hypertensive for the past 15 years. On examination, he was drowsy, with a nystagmus on looking to the left side and absent gag. He had mild incoordination in the left upper and lower limbs. The clinical diagnosis considered was a posterior circulation cerebrovascular accident and he was initiated on appropriate therapy for the same, though the plain computerized tomography of the brain did not show any evidence of a posterior circulation stroke. Antihypertensives and oral hypoglycemic agents were continued, and he was discharged when stable.

He presented 2 days later, with a fever, tachypnea, tachycardia and worsening of sensorium. Radiology and laboratory tests confirmed a diagnosis of aspiration pneumonia and diabetic ketoacidosis. He was empirically started on piperacillin/tazobactam. His hydration was restored and he was closely monitored. Blood sugars were controlled with insulin but his sensorium continued to remain poor. On the second day of admission he developed multiple episodes of small volume watery loose stools. Blood cultures sent grew S. flexneri serotype-2 on the 4th day, susceptible to cefaperazone/sulbactam, netilmicin, imipenam and meropenam, intermediate susceptible to amikacin, gentamicin, and piperacillin/tazobactem and resistant to ceftazidime and ceftriaxone. No fecal cultures were sent.

Molecular characterization

Detection of ESBL genes (blaTEM, blaSHV) was performed by polymerase chain reaction (PCR) using the primers as described previously (Dallenne et al., 2010; Tariq et al., 2012). Further screening for blaCTX-M-1, blaCTX-M-2, blaCTX-M-8, blaCTX-M-9, and blaCTX-M-25 was carried out by multiplex PCR for the isolate, as described earlier (Woodford et al., 2004), for AmpC (blaCMY, blaCIT, blaDHA, blaACC, blaACT, and blaFOX) as described previously (Perez-Perez and Hanson, 2002) as well as for sulfonamide-resistant genes dhfr1a, sul1 and sul2 described earlier (Toro et al., 2005; Hochhut et al., 2001). Screening for qnrA, qnrB, qnrS genes encoding for quinolone resistance was carried out by multiplex using a previously described protocol (Gay et al., 2006). Screening for integron class 1 and 2 was carried out by a protocol described earlier (Zhu et al., 2011). The isolate was found to carry the following genes-blaCTX-M-1, dhfr1a, sul2, qnrS and integrons class 1 and 2 [Figure 1].
Figure 1: Gel picture showing positive and negative bands for various genes encoding resistance. Lane 1: dhfr1a, Lane 2: blaOXA, Lane 3: sul2, Lane M: 100bp ladder, Lane 4: qnrS, Lane 5: Integrons 1 and 2, Lane 6: CTX-M-1, Lane 7: Negative control, Lane M: 100bp ladder

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Despite antibiotics being upgraded to meropenam, his condition did not improve and he progressed into a multiorgan dysfunction with hypotension and ARDS. He was discharged against medical advice and succumbed a day later.

   Discussion Top

The burden of infection by Shigella spp. is borne by children, adults being uncommonly affected.[1] Bacteremia due to the same is reported in <1% cases.[2] However, an immunocompromised adult is more likely prey to the invasive form of the disease. Various risk factors have been implicated in adults including HIV, malnutrition, malignancy and immunosuppressant drugs.[3] It remains cryptic as to what may have driven this patient into a Shigella bacteremia. The only apparent risk factors seemed to be his age and uncontrolled diabetes. To the best of our knowledge, only one similar report of Shigella sonnei in an uncontrolled diabetes mellitus patient has been reported.[4]

MDR Shigella spp. causing bacteremia has been reported infrequently both in India and globally, and as of now, is an uncommon entity. This isolate was found to carry dhfr1a, sul2, qnrS, and CTX-M-1 by molecular characterization, conferring resistance to cotrimoxazole, quinolones and cephalosporins respectively. A literature search reveals only a single report of MDR S. flexneri bacteremia which was in an immunocompetent adult;[5] and three reports in infants;[6],[7],[8] all of which were susceptible to cephalosporins.

Our report appears to be the first ESBL producing S. flexneri isolate causing bacteremia in an adult with uncontrolled diabetes mellitus. The occurence of an MDR S. flexneri causing bacteremia in such an immunocompromised patient is a grave cause for concern.

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Conflicts of interest

There are no conflicts of interest.

   References Top

Ashkenazi S. Shigella infections in children: New insights. Semin Pediatr Infect Dis 2004;15:246-52.  Back to cited text no. 1
Reddy EA, Shaw AV, Crump JA. Community-acquired bloodstream infections in Africa: A systematic review and meta-analysis. Lancet Infect Dis 2010;10:417-32.  Back to cited text no. 2
Keddy KH, Sooka A, Crowther-Gibson P, Quan V, Meiring S, Cohen C, et al. Systemic shigellosis in South Africa. Clin Infect Dis 2012;54:1448-54.  Back to cited text no. 3
Dronda F, Parras F, Martínez JL, Baquero F. Shigella sonnei bacteremia in an elderly diabetic patient. Eur J Clin Microbiol Infect Dis 1988;7:404-5.  Back to cited text no. 4
Munim FC, Vandana KE, Acharya V, Mukhopadhyay C. Multidrug-resistant Shigella flexneri bacteremia in an immunocompetent adult. Indian J Pathol Microbiol 2012;55:607-8.  Back to cited text no. 5
[PUBMED]  Medknow Journal  
Erqou S, Teferra E, Mulu A, Kassu A. A case of shigellosis with intractable septic shock and convulsions. Jpn J Infect Dis 2007;60:314-6.  Back to cited text no. 6
Saraswathi K, De A, Jog A, Gogate A. Shigella septicemia. Indian Pediatr 2002;39:777-9.  Back to cited text no. 7
Yen JB, Chang KW, Wu TL, Kuo AJ, Su LH. Shigella flexneri sepsis in an infant. Chang Gung Med J 2003;26:611-4.  Back to cited text no. 8

Correspondence Address:
Dr. V Balaji
Department of Microbiology, Christian Medical College, Vellore - 632 004, Tamil Nadu
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0377-4929.188120

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