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ORIGINAL ARTICLE
Year : 2022  |  Volume : 15  |  Issue : 3  |  Page : 335-340  

Site-specific bacteriology of tropic ulcers and their antibiotic sensitivity: A cross-sectional study


1 Department of Physical Medicine and Rehabilitation, King George's Medical University, Lucknow, Uttar Pradesh, India
2 Government of Uttar Pradesh, India

Date of Submission25-Oct-2020
Date of Decision28-Oct-2021
Date of Acceptance08-Nov-2021
Date of Web Publication22-Jan-2022

Correspondence Address:
Sudhir Ramkishore Mishra
Department of Physical Medicine and Rehabilitation, King George's Medical University, Lucknow - 226 003, Uttar Pradesh
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/mjdrdypu.mjdrdypu_589_20

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  Abstract 


Introduction: The trophic ulcers are usually presented in the form of diabetic ulcer, leprotic ulcer, and pressure ulcer. The usual site for ulceration in trophic ulcer is the bony prominence on body part devoid of sensation. The chronic wounds management in health-care setting have significant impact on the patient's physical, mental, and financial health. In trophic ulcer management factors such as cause of ulcer, its location, size, and duration should be considered. Infection in such trophic ulcer leads to increase disease activity results delayed wound healing. Thus, a study was designed with aim to find relation between location of trophic ulcer and its infection status. Materials and Methods: This retrospective cross-sectional study includes 95 patients with infected trophic ulcers admitted between January 2015 and March 2020 from our tertiary care rehabilitation center. Cultured bacterial species were tested against following 23 drugs Amikacin, Gentamycin, Levofloxacin Ciprofloxacine, Piperacillin + Tazobactum, Ceftriaxone, Cefepime, Meropenem, Imipenem, Ampicillin, Ceftazidime, Amoxiclav, Cotrimoxazole, Cefotaxime, Erythromycin, Clindamycin, Tetracycline, Cefoxitin, Chloramphenicol, Colistin, Tobramycin, Vancomycin, and Aztreonam. Results: The common sites of trophic ulcer involvement were sacrum (32%), heel (29%), forefoot (17%), ischium (12%), knee (6%), and greater trochanter (4%). Eight different bacterial species were isolated, which were Staphylococcus aureus (26%), Enterococcus (9%) and six Gram-negative bacteria, which were Pseudomonas (24%), Proteus (17%), Klebsiella (11%), E. coli (7%), Enterobacter (3%), and Acinetobacter Baumani (3%). S. aureus was found most susceptible to Vancomycin (16%), followed by Amikacin (14%) and full resistant to ampicillin, tobramycin, and Aztreonam. Pseudomonas was found most susceptible to Meropenem (13%), followed by Amikacin (12%) and full resistant to Cotrimoxazole, Erythromycin, Clindamycin, Cefoxitin, Chloramphenicol, and Vancomycin. Overall, Amikacin followed by Meropenem was found susceptible against 56% and 52% of cases, respectively. Conclusion: The infected trophic ulcers which require either medical or surgical treatment, in both these situations antibiotics play vital role, thus, to avoid the development of antibiotics resistant, two drug regimens should be followed either by adding Amikacin or Meropenem to the primary single drug regime.

Keywords: Antibiotic susceptibility, microbial infections, Pseudomonas, Staphylococcus aureus, trophic ulcer


How to cite this article:
Mishra SR, Mishra S, Yadav G, Kumar D, Gupta A K. Site-specific bacteriology of tropic ulcers and their antibiotic sensitivity: A cross-sectional study. Med J DY Patil Vidyapeeth 2022;15:335-40

How to cite this URL:
Mishra SR, Mishra S, Yadav G, Kumar D, Gupta A K. Site-specific bacteriology of tropic ulcers and their antibiotic sensitivity: A cross-sectional study. Med J DY Patil Vidyapeeth [serial online] 2022 [cited 2022 May 21];15:335-40. Available from: https://www.mjdrdypv.org/text.asp?2022/15/3/335/336323




  Introduction Top


In Greek “Trophic” means nutrition. Mosby's Medical Dictionary 2009 defines trophic ulcer as “a pressure ulcer caused by external trauma to a part which is poorly conditioned due to disease, vascular insufficiency or loss of afferent nerve fibers.”. Based on pathological cause of origin of trophic ulcers are classified as neurogenic, vascular (arterial/venous), and systemic causes or malnutrition.[1] During activities of daily living, repetitive high pressures over bony prominence are the usual site of a trophic ulcer. Changing gait or modifying activity, change of posture are the avoidance measures adapted by people with normal sensation to relieve the discomfort cause by the repetitive pressure, but in patients with peripheral sensory deficits this measures are absent, resulting in repetitive trauma, skin breakdown, and ulceration.[1]

The common cause of trophic ulcer is diabetic ulcer, leprotic ulcer, and pressure ulcer. The usual site for ulceration in trophic ulcer is the bony prominence which are deprive of normal sensation. In such patients, pressure between the external body surface and bony prominence occludes the capillaries leads to anoxia of surrounding and underlying tissues and if this pressure continues for a critical duration, cell death occur, resulting in soft-tissue necrosis and eventual ulceration.[2]

Wounds that do not heal within 3 months are often considered chronic.[3] Chronic wound management in health-care setting has significant impact on the patient's health and in reducing morbidity, thus improving function and quality of life. Generally, all wounds are contaminated with microorganisms which are a part of the saprophytic microbiota of the skin, the sort and quantity of those microorganisms vary from one wound to other. Factors such as wound duration, size, location, and origin should be taken under consideration during wound management due to their impact on wound colonization and infection.[4]

Infection is one of the important extrinsic factor which delays the wound healing which further contribute to wound chronicity, morbidity, and mortality.[5] Chronic wounds which do not show signs of improvement and remain in an inflammatory stage due to multiple factors such as age of patient, bacterial colonization of wound, leads to toxin production, collagen degradation results chronicity of wounds.[6]

There are numerous studies on pressure ulcers, role of microbes in chronic wounds, resistance of antibiotics in infected wounds, prevalence of pressure injuries in neuropathies, but there are very few studies where we can find a relationship between the site of trophic ulcer and its association with microbiota and antibiotic susceptibility. Thus, a retrospective cross-sectional study was designed with following aims and objective.

  1. To find a relationship between the site of trophic ulcer and its association with microbiota and antibiotic susceptibility
  2. To study the site specific prevalence of bacteria in trophic ulcers
  3. To study the antibiotic susceptibility from same trophic ulcers.


This study will be helpful in management of such trophic ulcer.


  Materials and Methods Top


After taking permission from departmental ethical committee letter R. No. 2982(A)-2020 dated May 22, 2020 at King Gorge's Medical University, to analyze the patient's treatment records from January 2015 to March 2020. This retrospective cross-sectional study was performed by analyzing records of all the patients with trophic ulcers from the Department of Physical Medicine and Rehabilitation (PMR). All the patients were screened and selected based on following inclusion and exclusion criteria [Figure 1].
Figure 1: Screening of patient

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Inclusion criteria

  1. All the patients took treatment for ulcers due to neuropathic cause
  2. Patients with confirmed infected trophic ulcer
  3. The patient given consent to evaluate the records during treatment.


Exclusion criteria

  1. Patient with surgical wound infection
  2. Patient with traumatic wound infection without neuropathy
  3. Patient's record with missing consent form to evaluate the records.


This study included, all the patients treated for trophic ulcer with different morbidities such as spinal cord injuries (paraplegia, tetraplegia, meningomyelocele, diastematomyelia, etc.), diabetic foot, Hansen disease, etc., In this study, diagnosis of trophic ulcer infection was confirmed by microbiological culture from ulcers at microbiology lab of King Gorge's Medical University, Lucknow, for which sample collection was done by Levine technique.[7] In this technique, a cotton Q-tip twirled for 5 s on area of an open wound measuring a minimum of 1 cm2 in size with sufficient pressure to incite minimal bleeding of the underlying wound bed, which is taken into account as viable sampling alternative to tissue biopsy, further the X-ray and sinography of involved site was done to see the bony changes and the extent of abscess cavity or sinus if any.

Culture technique

All the collected sample were sent for bacterial culture at microbiology lab of King George's Medical University, where all these samples were processed for Gram staining and aerobic culture. For aerobic cultures samples were incubated at 37°C and plated on Mac Conkey's agar (MA) and blood agar (BA) for 48 h. Identification and characterization of the colonies were done on the basis of microscopic, Gram staining, and colony characteristics on BA and MA. The isolated colonies were put on matrix-assisted laser desorption/ionization-time of flight for rapid identification.

Antimicrobial susceptibility was performed on Muller Hinton agar by Kirby Bauer disc diffusion method and Clinical and Laboratory Standards Institute guidelines were followed.[8] All the isolated bacterial species were tested against following 23 antibiotics: Amikacin, Gentamycin, Levofloxacin, Ciprofloxacine, Piperacillin + Tazobactum, Ceftriaxone, Cefepime, Meropenem, Imipenem, Ampicillin, Ceftazidime, Amoxiclav, Cotrimoxazole, Cefotaxime, Erythromycin, Clindamycin, Tetracycline, Cefoxitin, Chloramphenicol, Colistin, Tobramycin, Vancomycin, and Aztreonam. The most susceptible antibiotics were selected for the treatment of infection.


  Results Top


In this study, we collected data of 95 patients, admitted in PMR ward with chronic trophic ulcer at different sites, along with their culture findings and susceptibility tests against all the 23 antibiotics. There were 84 male (88.54%) and 11 female (11.46%) with male-to-female ratio of 7.7:1. The mean age of presentation were 31 years (range: 6–55 years). Cause of trophic ulcers was traumatic spinal cord injury in 57% of cases (paraplegia 53%, and tetraplegia 4%), nontraumatic spinal cord injury in 31% of cases (meningomyelocele 26%, prolapse intervertebral disc 2%, lumbar teratoma 2%, and diastometamelia 1%) leprosy in 8% of cases and diabetic foot in 4% of cases. Site of trophic ulcer involvement were sacrum (32%), heel (29%), forefoot (17%), ischium (12%), knee (6%), and greater trochanter (4%).

Distribution of patients based on the site of ulcer and related pathology presented in [Table 1].
Table 1: Patient's distribution base on site of trophic ulcer and diagnosis

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There were 8 different bacterial species isolated from all the ulcers and in some cases there were polymicrobial infection (infection with more than one bacteria). Among the isolated microorganisum two were Gram positive bacteria, Staphylococcus aureus (26%) and Enterococcus (9%), six were Gram negative bacteria, Pseudomonas (24%), Proteus (17%), Klebsiella (11%), E. coli (7%), Enterobacter (3%), and AcinetobacterBaumani (3%). In this study, the S. aureus and Pseudomonas were the most common Gram-positive and Gram-negative isolated bacteria respectively.

Distribution of isolated bacteria and site of trophic ulcer are shown in [Table 2] and their frequency is shown in [Figure 2].
Figure 2: Frequency distribution of cultured bacterial isolate with site of trophic ulcer

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Table 2: Isolated bacterial distribution based on site of ulcer

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Pseudomonas was the most predominant bacterium in sacral, heel, and greater trochanteric trophic ulcer, S. aureus was most predominant bacterium in foot and knee trophic ulcer whereas Proteus was most predominant bacterium in ischial trophic ulcer. Overall sacrum followed by heel was the most common site of trophic ulcer and S. aureus followed by Pseudomonas were the most common bacteria in trophic ulcer.

Susceptibility of all the eight isolated bacteria was tested against all 23 antibiotics. The susceptibility profile of all the isolated bacteria against antibiotic is shown in [Table 3]. Full resistance of bacteria to drug is indicated by 0 in [Table 3], which indicates S. aureus, as most susceptible to Vancomycin (16%), followed by Amikacin (14%) and Gentamycin (11%) and Pseudomonas as most susceptible to Meropenem (13%) followed by Amikacin (12%) and Imipenem (11%). When it comes to resistance profile of isolated bacteria S. aureus found full resistance to Ampicillin, Tobramycin, and Aztreonam and Pseudomonas was found fully resistant to Cotrimoxazole, Erythromycin, Clindamycin, Cefoxitin, Chloramphenicol, and Vancomycin.
Table 3: Susceptibility percentage of isolated bacterial with various antibiotics

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  Discussion Top


The common cause of trophic ulcer is diabetic ulcer, leprotic ulcer, and pressure ulcer1. In this study we found spinal cord pathology (88%) as the most common cause of trophic ulcer followed by leprosy 8% and diabetic foot 4%. This may be because King George's Medical University have one of the largest spinal cord injury rehabilitation center in India. Bhattacharya and Mishra in their study found commonest site of trophic (pressure) ulcer as the pelvic region (i.e. sacral, ischial, perineal, and trochanteric regions) followed by buttock and/or legs.[9] In this study, the most common site of trophic ulcer was sacrum followed by heel and foot.

Bessa et al. found polymicrobial infections in 27.2% of the wounds.[4] In this study we found polymicrobial infection in 15% of cases. Past studies about the microbiology of pressure ulcers have found Pseudomonas, P. mirabilis, S. epidermidis and S. aureus, as common bacterial species. Dana and Bauman found E. coli as the most common Gram-negative rods in infection of the pressure ulcers and Pseudomonas, Stenotrophomonas maltophilia or Acinetobacter baumannii species as more frequently in SCI patients.[10] Burmolle et al. found S. aureus as the most common Gram-positive and Pseudomonas as the most common Gram-negative isolated microorganism in trophic ulcer.[11] Similarly, in this study, we found S. aureus as the most common Gram-positive and Pseudomonas as the most common Gram-negative isolated bacterial species, which is supported by past studies.

According to past studies bacteria like S. aureus and Pseudomonas produce very destructive virulence factors which delay wound healing by maintaining wound infection. S. aureus has adhesive matrix molecules such as fibronectin-binding proteins A and B, clumping factors A and B, collagen-binding protein, bone sialo-protein binding protein, and fibrinogen-binding protein. These virulence factors lead to increase the prevalence of methicillin-resistant S. aureus in the community.[12] Similarly, elastase has been found to be associated pathogenicity of Pseudomonas in the wound environment.[13]

Dana and Bauman studied the male genital microbiota, they found Pseudomonas and Klebsiella in 20%–80% of cases other bacterial species were Acinetobacter, E. coli, Proteus, Enterobacter, and Citrobacter freundii, which they explained by the fact that the infection starts by colonization of frail skin with bacteria from the urogenital and digestive tracts.[9] In this study as per objective, the most common bacteria in sacral trophic ulcer was Pseudomonas followed by S. aureus, while the least common isolated pathogen was Enterobacter. In case of ischial pressure ulcers, the most common isolated bacteria was Enterobacter followed by S. aureus, while the least common was Proteus. However, when we consider perianal region as whole S. aureus 22% was the most common and Acinetobacter 7% was the least common isolate.

Ogba et al. in their study on foot ulcer found S. aureus (32.9%) and Klebsiella pneumonia (20.4%) as the most prevalent and least prevalent isolated pathogen, respectively.[14] In this study, we found S. aureus 30% and Pseudomonas 30% as the most prevalent and E. coli 9% as least prevalent isolated pathogen in foot (fore + mid + hind) ulcers. As per the objective of study when we assess site-specific bacteria in trophic ulcer, in cases of heel and fore + mid foot ulcer, we found Pseudomonas and S. aureus as most prevalent pathogen respectively.

Other site about which literatures are not available are Greater trochanteric ulcer and knee ulcer in both site, we found Pseudomonas and S. aureus as most prevalent isolated pathogen.

The surgical intervention of infected trophic ulcers by debridement/musculocutaneous flaps require antibiotic cover, but it is difficult to start any empirical therapy as large variety of bacterial species are involved in such infections. Kwon and Armstrong recommend that antibiotics should not be prescribed for clinically uninfected wounds to prevent infection or promote wound healing. When classic signs of infection (erythema, edema, heat, pain, and purulent discharge) are not clear due to ischemia and neuropathy in trophic wounds, secondary signs of infection such as serous exudates, delayed healing, friable granulation tissue, discolored granulation tissue, foul odor, pocketing of the wound base, and wound breakdown can be taken as an evidence of infection. When it comes to empirical therapy a narrow-spectrum oral antibiotics can be administered for mild infections and broad-spectrum parenteral antibiotics administered for to severe infections. However it is always appropriate to administer a brief course, culture-directed antibiotic and observe the therapeutic response to reduce the incidence of adverse events, antibiotic resistance, and cost.[15]

Bessa et al. found Gram-positive bacteria have low resistant profile and they always responds to Vancomycin and to Linezolid.[4] Mylotte et al. found Erythromycin as the most effective antibiotic agent against S. aureus.[16] In contrast we found S. aureus most susceptible to Vancomycin followed by Amikacin and Gentamycin and full resistant to Ampicillin, Tobramycin, and Aztreonam. Bessa et al. also found Pseudomonas as highly resistant bacterium simultaneously to many drugs like ampicillin, amoxicillin/clavulanic acid, ertapenem and trimethoprim/sulfamethoxazole. In this study we found, Pseudomonas most susceptible to Meropenem followed by Amikacin, Imipenem full resistant to Cotrimoxazole, Erythromycin, Clindamycin, Cefoxitin, Chloramphenicol and Vancomycin. In this study, overall the single drugs against which most of the isolated bacteria were susceptible was Amikacin (56) followed by Meropenem (52).

With the limitation of study, it is evident from the results that only aerobic/facultative microorganisms were investigated. The anaerobes are frequently found potential pathogen in wounds and they are very important component of infected leg ulcers.[4],[17] Despite the demonstrated role and importance of anaerobes in wound infection, the techniques to isolate them still not being performed in many clinical laboratories as the culture of anaerobes is more time-consuming, laborious, and expensive and thus, too demanding.


  Conclusion Top


Infected trophic ulcer required either aggressive medical or surgical treatment, in both these situation antibiotics play vital role, thus, to reduce the incidence of adverse events, development of antibiotics resistance, and cost of treatment, treatment of a trophic ulcer should observed, short duration and directed by culture and susceptibility of pathogen. It is always better to follow the two drug regimens by adding Amikacin or Meropenem to the primary single drug regime.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
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Dana AN, Bauman WA. Bacteriology of pressure ulcers in individuals with spinal cord injury: What we know and what we should know. J Spinal Cord Med 2015;38:147-60.  Back to cited text no. 10
    
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Burmolle M, Thomsen TR, Fazli M, Dige I, Christensen L, Homøe P, et al. Biofilms in chronic infections – A matter of opportunity – Monospecies biofilms in multispecies infections. FEMS Immunol Med Microbiol 2010;59:324-36.  Back to cited text no. 11
    
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Kadkhoda H, Ghalavand Z, Nikmanesh B, Kodori M, Houri H, Taghizadeh Maleki D, et al. Characterization of biofilm formation and virulence factors of Staphylococcus aureus isolates from paediatric patients in Tehran, Iran. Iran J Basic Med Sci 2020;23:691-8.  Back to cited text no. 12
    
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Suleman L. Extracellular bacterial proteases in chronic wounds: A potential therapeutic target? Adv Wound Care (New Rochelle) 2016;5:455-63.  Back to cited text no. 13
    
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Ogba OM, Nsan E, Eyam ES. Aerobic bacteria associated with diabetic foot ulcers and their susceptibility pattern. Biomed Dermatol 2019;3:1-6.  Back to cited text no. 14
    
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Kwon KT, Armstrong DG. Microbiology and antimicrobial therapy for diabetic foot infections. Infect Chemother 2018;50:11-20.  Back to cited text no. 15
    
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Mylotte JM, Graham R, Kahler L, Young BL, Goodnough S. Impact of nosocomial infection on length of stay and functional improvement among patients admitted to an acute rehabilitation unit. Infect Control Hosp Epidemiol 2001;22:83-7.  Back to cited text no. 16
    
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    Figures

  [Figure 1], [Figure 2]
 
 
    Tables

  [Table 1], [Table 2], [Table 3]



 

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