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Unusual Severe Extra-Intestinal Manifestations of a Common Enteric Pathogen-Aeromonas Spp
Barnini Banerjee1, Mridula Madiyal2, Lingadakai Ramchandra3
1Assistant Professor, Department of Microbiology, Kasturba Medical College, Manipal University, Manipal, Karnataka, India.
Introduction:
Aeromonas spp. are halophilic, Gram-negative bacilli. They are widely distributed in the soil and aquatic environment and have been associated with various extra-intestinal infections, such as skin and soft-tissue infections, meningitis, bacteraemia etc. The most common species associated with extra-intestinal infection is Aeromonas hydrophila.
Aim:
To get the overview of clinical presentations, underlying predisposing factors associated with the extra-intestinal infections caused by Aeromonas species and their antimicrobial susceptibility pattern.
Materials And Methods:
Extra-intestinal cases of Aeromonas spp. admitted during December 2015 to October 2016 in the tertiary care hospital of South Karnataka coastal region were analysed retrospectively. The isolates were identified by Matrix Assisted Laser Desorption Ionization Time-of-Flight (MALDI-TOF) VITEK®MS and antimicrobial susceptibility testing was performed by VITEK®2 system (bioMérieux, Inc., Durham, NC) respectively. Clinical manifestations and management of the cases were noted from the clinical records. Clinical and microbiological findings presented as mean±standard deviation, frequency and percentage.
Results:
We included 26 cases in this study, from whom Aeromonas spp. were isolated alone or with another microorganism. Most widespread infection was Skin and Soft Tissue Infection (SSTI) (24, 92.3%). In 50% (12/24) cases, SSTI developed due to trauma. In 45.8% (11/24), underlying co-morbid conditions were present. The common site of infection was lower extremities (16/24, 66.7%) and 62.5% (15/24) of them presented with severe gangrene of the affected site. Other than SSTI, we encountered with two cases of keratitis and cholangitis respectively. A. hydrophila were frequently isolated species (23/26, 88.5%). The analysis of antimicrobial susceptibility showed, 13% isolates were Multidrug Resistant (MDR). Carbapenem resistance was also noted.
Conclusion:
We had isolated Aeromonas spp. from different extra-intestinal sites. Most common extra-intestinal manifestation by this organism was post-traumatic wound infection. Clinical spectrum of this infection confused the clinician with other organisms like group B Streptococcus, Clostridium spp. etc., and mislead them in empirical management. Finally with the microbiological support all the cases were treated either conservatively or in combination with surgical debridement or amputation depending on the situation.
Insights
Aeromonas species commonly cause post-traumatic skin and soft tissue infections, often leading to severe gangrene. Antimicrobial resistance, including carbapenem resistance, was observed in multidrug-resistant Aeromonas isolates.
Area of Science:
- Microbiology
- Infectious Diseases
- Clinical Medicine
Background:
- Aeromonas species are Gram-negative bacilli found in aquatic environments.
- They are associated with various extra-intestinal infections, including skin and soft-tissue infections (SSTI).
- Aeromonas hydrophila is the most common species linked to extra-intestinal infections.
Purpose of the Study:
- To investigate clinical presentations of Aeromonas-associated extra-intestinal infections.
- To identify predisposing factors for these infections.
- To determine the antimicrobial susceptibility patterns of Aeromonas isolates.
Main Methods:
- Retrospective analysis of extra-intestinal Aeromonas cases from December 2015 to October 2016.
- Isolate identification using Matrix Assisted Laser Desorption Ionization Time-of-Flight (MALDI-TOF) VITEK®MS.
- Antimicrobial susceptibility testing performed with the VITEK®2 system.
Main Results:
- Skin and Soft Tissue Infection (SSTI) was the most common presentation (92.3%).
- Trauma was a frequent cause of SSTI (50%), with underlying comorbidities in 45.8%.
- Severe gangrene of the lower extremities was noted in 62.5% of SSTI cases. Aeromonas hydrophila was the predominant species (88.5%).
- 13% of isolates were multidrug-resistant (MDR), with observed carbapenem resistance.
Conclusions:
- Aeromonas species can cause severe extra-intestinal infections, particularly post-traumatic wound infections.
- The clinical presentation can mimic other bacterial infections, potentially leading to misdiagnosis and delayed treatment.
- Microbiological guidance is crucial for appropriate management, ranging from conservative treatment to surgical intervention.
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