Case Report Aeromonas hydrophila Sepsis Associated with...

Case ReportAeromonas hydrophila Sepsis Associated withConsumption of Raw Oysters

Ivan Nikiforov, John Goldman, Pramil Cheriyath, Anix Vyas, and Vinod Nookala

Department of Medicine, PinnacleHealth System, Harrisburg Hospital, BMAB 3-C, 207 South Front Street, Harrisburg, PA 17104, USA

Correspondence should be addressed to Ivan Nikiforov; [email protected]

Received 9 July 2014; Revised 25 September 2014; Accepted 12 October 2014; Published 19 November 2014

Academic Editor: Raul Colodner

Copyright © 2014 Ivan Nikiforov et al. This is an open access article distributed under the Creative Commons Attribution License,which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Introduction. Aeromonas hydrophila is a gram negative bacillus that is native to aquatic environments that is increasingly reported inhumans.This case is remarkable forA. hydrophilawith an initial presentation of acute pancreatitis.Case Presentation.A 61-year-oldmale presented to the emergency department with nausea, vomiting, and abdominal pain for two days. His past medical historywas significant for alcohol abuse. Initial laboratory examination showed an elevated white blood cell count, elevated lipase, andelevated liver function tests (LFT). Computer tomography (CT) showed peripancreatic inflammatory changes and retroperitonealfree fluid, suggestive of acute pancreatitis. The patient was treated with intravenous (IV) fluids and IV meropenem. After twodays, the patient developed sepsis and respiratory failure and was intubated. Blood cultures were positive forAeromonas hydrophilasensitive to ciprofloxacin which was added to his treatment. Additionally, it was discovered that this patient had recently vacationedin Florida where he consumed raw oysters. He was discharged home on the eighth day of the hospital admission. Conclusion.Thisis a rare case of A. hydrophila sepsis in an elderly patient with acute pancreatitis and a history of consumption of raw oysters. Thiscase suggests that A. hydrophila can cause disseminated infection in immunocompetent individuals.

1. Background

The infection of Aeromonas is often associated with con-sumption of fish, shellfish, and open wound exposure tocontaminated water. In humans, it can cause a wide varietyof infections including gastroenteritis, necrotizing fasciitis,myonecrosis, cellulitis, pneumonia, empyema, and urogenitaltract infections [1]. Aeromonas has also been associated withsepticemia in immunocompromised patients or those whohave experienced acute injury in an aquatic environmentallowing the bacteria to be introduced fromanoutside source.A small, but growing, subset of Aeromonas septicemia caseshave been reported in individuals with no risk factors [1].In this rare case, we report Aeromonas hydrophila septicemiaassociated with the consumption of raw oysters in a 61-year-old male with the initial presentation of acute pancreatitis.

2. Case Presentation

A 61-year-old male presented to the emergency room withthe complaint of nausea, vomiting, and abdominal pain

that began the previous day. Patient denied fever, diarrhea,constipation, bloody vomiting, or blood in the stool. His pastmedical history was only significant for alcohol abuse andsmoking. The patient was found to be in no acute distress.Vital signs were stable except for tachycardia at 121 beats perminute. Physical examination showed mild abdominal dis-tention, tenderness, hypoactive bowel sounds, and guarding.Laboratory examination revealed hemoglobin of 19.5 g/dL,leukocytes of 20,200 cells/mm3, lipase of 789U/L, AST of557 IU/L, ALT of 152 IU/L, and total bilirubin of 9.1mg/dL.Patient underwent CT scan of the abdomen which showedperipancreatic inflammatory changes and retroperitonealfree fluid, suggestive of acute pancreatitis. Due to concern ofprogression to pancreatic necrosis, the patient was admittedto the ICU, made NPO, and given IV fluids. The nextday the patient’s condition rapidly deteriorated, he becameunresponsive, and he developed respiratory failure requiringintubation. IV meropenem 500mg every 8 hours was startedempirically. On the third day of the hospital admission, theblood cultures returned positive forA. hydrophilawhich wereisolated from both aerobic and anaerobic vials.The specimen

Hindawi Publishing CorporationCase Reports in Infectious DiseasesVolume 2014, Article ID 163040, 3 pageshttp://dx.doi.org/10.1155/2014/163040

2 Case Reports in Infectious Diseases

was cultured on blood agar and chocolate agar. Gram stainshowed gram negative bacilli. Additional tests were donevia MicroScan system which showed a 91% probabilityof A. hydrophila group. Test for Vibrio cholera was nega-tive. Sequencing via rpoD gene confirmed A. hydrophila.Aeromonas was found to be sensitive to ciprofloxacin. IVciprofloxacin 400mg once daily was added to his antibiotictreatment. Additional history was obtained from the family,and it was discovered that the patient was vacationing inFlorida two weeks previously, where he ingested raw oysters.The patient recovered and was discharged on the eight day ofthe hospital admission.

3. Discussion

Aeromonas are gram negative facultative anaerobes, whichare indigenous to aquatic environments and are known forcausing infection in fish and animals. Their morphologicalcharacteristics include straight cocobacillary to bacillary cellswith an approximate diameter of 1.0micrometer, and a lengthof 3.5 micrometers. Aeromonas are usually motile with asingle polar flagellum [2]. Recently, there were increasedreports of debilitating infections in humans including fatalsepticemia. In 2004, it was estimated incidence ofAeromonassepticemia was 1.5 per million population [1]. As of 2009,there were 22 recorded species of Aeromonas with 2 newspecies being proposed [3]. The following species are asso-ciated with human clinical infection: Aeromonas hydrophila,A. aquariorum, A. veronii, A. caviae, A. trota, and A. media[3, 4].

Most Aeromonas are isolated in the laboratory usingblood agar with 20 𝜇g of ampicillin with the exceptionof A. trota due to its sensitivity to ampicillin [5]. Fur-ther identification is done based on the beta-hemolysis byscreening with the oxidase and spot indole test. In orderto distinguish Aeromonas form Vibrio and Plesiomonas theculture is grown in salt concentrations >6% with vibriostaticagent O/129 [2]. Gene sequencing is the best way to differ-entiate Aeromonas on a species level. The sequencing of 16SrRNA, a single housekeeping gene, was previously used todifferentiate Aeromonas species [6]. Unfortunately, it turnedout that horizontal transfer of the gene occurred betweenspecies making the results unreliable. The rpoD and gyrBgenes have been far more precise in identifying Aeromonasspecies [4]. If long term storage of the isolate is needed, therecommendation is to use trypticase soy broth with a 30%glycerol at a temperature of −80 centigrade [7].

The pathogenicity of A. hydrophila is caused by a type IIIsecretion system (TTSS) and act gene [8, 9]. TTSS enables thedelivery of toxins inside the host cells. A type II-secreted cyto-toxic enterotoxin (Act) which has hemolytic and cytotoxicfunctions is encoded by the act gene. These virulence factorsare linked to clinical infection and play a key role in thedisease process. A. hydrophila also has the enzymes elastaseand pectinaseare. These enzymes act on the immune systemand cause tissue destruction and hemolysis [10].Themajorityof Aeromonas infections usually present as gastroenteritiswith the symptoms of acute watery diarrhea, abdominal pain,

fever, vomiting, and nausea. The infections are self-limitingwith mild dehydration.Aeromonas infections are also knownto cause hemolytic urmeic syndrome, meningitis, peritonitis,wound infections, respiratory tract infection, ocular diseases,cellulitis, necrotizing fasciitis, peritonitis and cholangitis.Near drowning events have led to Aeromonas pneumonia [1].Our extensive literature review did not find a single reportof sepsis with the initial presentation of acute pancreatitis.Overall, there are no clinical symptoms that clearly help todistinguish Aeromonas sepsis from sepsis caused by otherbacteria, which is unfortunate since Aeromonas septicemiacan have a mortality rate as high as 46% [11].

The main treatment of Aeromonas is quinolones withlevofloxacin and ciprofloxacin being the antibiotics of choice.There are reports of resistance to quinolones due to theqnr protein. This product interferes with the DNA gyraseinhibitor of quinolones and grants resistance to them [12]. Ifthe qnr protein is present, additional antibiotic coverage withtrimethoprim-sulfamethoxazole or cephalosporins should beconsidered. Due to the above concerns, current recommen-dation does not include starting the patient on empiric antibi-otic treatment. Clinicians should wait for culture and sensi-tivity results before antibiotic treatment is started.Aeromonaspossess a wide range of beta-lactamases, generally mak-ing them resistant to penicillins, cephalosporins, extendedspectrum cephalosporins, clavulanic acid, tazobactam, andsulbactam [13].

4. Conclusion

Although Aeromonas septicemia is rare, it can carry a highmortality rate of 46%. Immunocompromised patients, thosewho suffered open wounds in aquatic environments andthose who have consumed fish and shellfish are at highestrisk. There has been an increasing amount of Aeromonasinfections in immunocompetent patients. Since there is widespread consumption of raw fish and shellfish in the UnitedStates, clinicians should consider Aeromonas infection inaddition to Vibrio infection as one of the differential diag-noses.

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper.

References

[1] J. M. Janda and S. L. Abbott, “The genus aeromonas: taxonomy,pathogenicity, and infection,” Clinical Microbiology Reviews,vol. 23, no. 1, pp. 35–73, 2010.

[2] P. R. Murray, E. J. Baron, J. H. Jorgensen, M. L. Landry, andM. A. Pfaller, “Aeromonas,” inManual of Clinical Microbiology,chapter 46, p. 716, American Society for Microbiology (ASM),9th edition, 2007.

[3] M. J. Figueras, A. Alperi,M. J. Saavedra et al., “Clinical relevanceof the recently described species Aeromonas aquariorum,”Journal of Clinical Microbiology, vol. 47, no. 11, pp. 3742–3746,2009.

Case Reports in Infectious Diseases 3

[4] M. Aravena-Roman, G. B. Harnett, T. V. Riley, T. J. J. Inglis, andB. J. Chang, “Aeromonas aquariorum is widely distributed inclinical and environmental specimens and can be misidentifiedas Aeromonas hydrophila,” Journal of Clinical Microbiology, vol.49, no. 8, pp. 3006–3008, 2011.

[5] S. L. Abbott, W. K. W. Cheung, and J. M. Janda, “The genusAeromonas: biochemical characteristics, atypical reactions, andphenotypic identification schemes,” Journal of Clinical Microbi-ology, vol. 41, no. 6, pp. 2348–2357, 2003.

[6] N. Borrell, S. G. Acinas, M.-J. Figueras, and A. J. Martınez-Murcia, “Identification ofAeromonas clinical isolates by restric-tion fragment length polymorphism of PCR-amplified 16SrRNA genes,” Journal of Clinical Microbiology, vol. 35, no. 7, pp.1671–1674, 1997.

[7] T. E. Erova, J. Sha, A. J. Horneman et al., “Identification of a newhemolysin fromdiarrheal isolate SSUofAeromonas hydrophila,”FEMS Microbiology Letters, vol. 275, no. 2, pp. 301–311, 2007.

[8] M. R. Chacon, L. Soler, E. A. Groisman, J. Guarro, and M. J.Figueras, “Type III secretion system genes in clinical aeromonasisolates,” Journal of ClinicalMicrobiology, vol. 42, no. 3, pp. 1285–1287, 2004.

[9] J. Sha, L. Pillai, A. A. Fadl, C. L. Galindo, T. E. Erova, andA. K. Chopra, “The type III secretion system and cytotoxicenterotoxin alter the virulence of Aeromonas hydrophila,”Infection and Immunity, vol. 73, no. 10, pp. 6446–6457, 2005.

[10] S. L. Abbott, W. K. W. Cheung, and J. M. Janda, “The genusAeromonas: Biochemical characteristics, atypical reactions, andphenotypic identification schemes,” Journal of Clinical Microbi-ology, vol. 41, no. 6, pp. 2348–2357, 2003.

[11] M. Dryden and R.Munro, “Aeromonas septicemia: relationshipof species and clinical features,” Pathology, vol. 21, no. 2, pp. 111–114, 1989.

[12] X. Xiong, E. H. C. Bromley, P. Oelschlaeger, D. N. Woolfson,and J. Spencer, “Structural insights into quinolone antibioticresistance mediated by pentapeptide repeat proteins: conservedsurface loops direct the activity of a Qnr protein from a Gram-negative bacterium,” Nucleic Acids Research, vol. 39, no. 9, pp.3917–3927, 2011.

[13] T. R. Walsh, R. A. Stunt, J. A. Nabi, A. P. MacGowan, and P.M. Bennett, “Distribution and expression of 𝛽-lactamase genesamongAeromonas spp,” Journal of Antimicrobial Chemotherapy,vol. 40, no. 2, pp. 171–178, 1997.

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