Burn injury is one of the most common and devastating forms of trauma and a major public health concern all around the world. The burn patients have a unique predisposition to different infections which are linked to impaired resistance from disruption of the skin’s mechanical integrity and generalized immune suppression. The skin barrier is replaced by a protein-rich, vascular environment that provides a favorable niche for microbial colonization and proliferation by one or more sepsis of microorganisms anywhere and becomes better placed to cause damage to the host sterile tissues. A wound can be infected by a variety ranging from bacteria to fungus and parasites mostly gram-positive and gram-negative microorganisms. Additionally, the migration of the immune cell is hampered, which contributes to the septic process [1] - [6]. It has been estimated that 75% of all deaths following thermal injuries are related to infection. Initially, the burned area is considered free of major microbial contamination. However, gram-positive bacteria in the depths of sweat glands and hair follicles may survive the heat of initial injury and unless topical antimicrobial agents are applied, these bacteria heavily colonize the wounds within the first 48 h post-injury [7] [8] [9]. Although any organisms is a potential pathogen in burned patients, coagulase-negative Staphylococci and S.aureus were the most common gram-positive pathogens and Pseudomonas aeruginosa, E. coli, and K.pneumonae and Proteus vulgaris were the common gram-negative microorganisms [10] [11]. Thus, the current research study aimed to determine the microorganisms and their susceptibility patterns which were isolated from burn wounds of patients at the National Institute of Burning and Plastic Surgery Unit of Dhaka Medical College Hospital Dhaka. Burns is one of the most common traumas. There are about 2 million fires each year, 1.2 million people with burn injuries, 100,000 hospitalizations, and 5000 patients die from related complications [12]. Nosocomial infections (NI) are common in burn patients due to the typical features of the disease: loss of the first line of defense against microbial invasion; the presence of devitalized, a vascularized tissue that provides a favorable environment for microbial growth; alterations in the specific and nonspecific components of the immune system; gastrointestinal translocation; and extended hospitalization and multiple invasive diagnostic and therapeutic procedures [13] [14]. In recent years, drug resistance to human pathogenic bacteria is being commonly reported from all over the world. However, the situation is alarming in developing as well as developed countries due to indiscriminate use of antibiotics [15], although pharmaceutical industries have produced a large number of newer antibiotics in the last three decades. The reason behind this is that microorganisms are becoming resistant to both older and newer antibiotics [16]. Besides, bacteria have the genetic ability to transmit and acquire resistance to drugs which are utilized as therapeutic agents and transferring the resistance from one bacterium to another. Antibiotics provide the main basis for the therapy of microbial infections. Since the discovery of these antibiotics and their uses as chemotherapeutic agents, there was a belief in the medical fraternity that this would lead to the eventual eradication of infectious diseases [17]. However, overuses of antibiotics have become the major factor for the emergence dissemination of multidrug-resistant strains of several groups of microorganisms. Resistant bacteria impact public health in such a way that it increases morbidity and mortality from treatment failures and increases healthcare cost as newer and more expensive antibiotics are needed to treat infections [18]. Resistant bacteria are emerging worldwide as a threat to the favorable outcome of common infections in the community and hospital settings [19]. Staphylococcus aureus showed resistance due to the production of penicillinase with the ability to hydrolyzing penicillin, the first generation resistant due to beta-lactamases, and third-generation cephalosporin are resistant due to the production of extended-spectrum bête lactamases (ESBLS). Microorganisms are the enemies to mankind and cause very profound damage to the human body as well as other living organisms. The agents, which can kill the microbes or arrest the multiplication, are called the antimicrobial agent’s drugs. There are a lot of antimicrobial drugs of which some are discovered or established [20] [21].

Prevalence of microorganisms in burn wound samples (Figure 1): Out of 50 samples, 45 were found to be hugely populated with bacterial load from 120 - 500 CFU/plate, among them almost all were found to harbor Pseudomonas spp. in the range of 130 - 430 CFU/plate (Table 1 and Table 2). Growth and proliferation of S. aureus was observed in 44 samples ranges from 15 - 360 CFU/plate. Among the enteric bacteria, Klebsiellaspp. was found to prevail among 32 samples in the ranges of 5 - 30 CFU/plate, and the comparative lower frequency was observed in the case of Proteus spp. in 23 samples and E. coli in 13 samples.

*TVC (total viable count). Among 50 samples (1 - 28) were male patients and rest of the samples (29 - 50) were female patients. All the experiments have been done three times and the results were reproducible. One representative data have been shown.

TSI = Triple Sugar Iron, R = Red (alkaline), Y = Yellow (acidic), MR = Methyl Red, VP = Voges Proskauer.

Drug-resistance traits of the isolates: There are 8 common drug used, amikacin (n = 45, 20%), cefepime (n = 45, 20%), imipenem (n = 45, 40%), merupenem (n = 45, 60%) ciprofloxacin (n = 45, 65%), gentamycin (n = 45, 70%), nitrofurantonin (n = 45, 90%) were found to be ineffective against Pseudomonas spp. (Figure 2(a)), cefepime (n = 44, 30%), amikacin (n = 44, 80%), gentamycin (n = 44, 90%) were found to be ineffective against S.aureus.(Figure 2(b)), cefepime (n = 13, 50%), amikacin (n = 13, 50%), and flucloxacillin (n = 13, 80%) were found to be ineffective against E. coli isolates (Figure 2(c)). Cefepime (n = 23, 60%), imipenem (n = 23, 80%), flucloxacillin (n = 23, 90%), were found to be ineffective against Klebsiellaspp. (Figure 2(d)).

The prototype of bacterial resistance appears to be imperative for epidemiological study. It is worth noting that the multidrug-resistant isolates of Acinetobacterbaumanni and P.aeruginosa are particular concern in burn care units. In our study, almost all the isolates exhibited the multi-drug resistance trait against commonly used antibiotics. However, an important clinical consideration has to be taken on the fact that since E.coli and Klebsiella pneumonia are well known to be the extended spectrum β-lactamase producers; these isolates found in our study may be further subjected for study [23] [24] and the prevalence of bacteria in 50 burn wound swabs was shown in the bacterial isolates were found in 45 (90%) wound swab samples, and only 5 samples (10%) were negative in bacterial growth. In this study the total viable count CFU/plate was found the highest amount in the second-degree burn patients. The results showed that Pseudomonas aeruginosa was common in all positive samples (57%) followed by Staphylococcus aureus (35%), Klebsiella spp. (5%), Proteus spp. (2%), and E. coli (1%). All detected pathogens were Catalase positive and Oxidase negative but Pseudomonas spp. was Oxidase positive. Most of them were Indole, MR, VP test positive but Pseudomonas spp. was Indole, MR and VP negative, S aureus Indole negative, Klebsiella was MR negative, Proteus, and E. coli VP negative. In Citrate Utilization Test all were positive except S. aureus and E. coli. In Triple Sugar Iron Agar Test all organisms were positive except Pseudomonas aeruginosa and S. aureus among them Proteus was unable to produce H₂S. Pseudomonas and S. aureus were resistant to all antibiotics but S. aureus was sensitive to Imipenem and Meropenem and partially sensitive to flucloxacillin. E. coli were 100% sensitive to ciprofloxacin, Klebsiella spp. were sensitive to Amikacin and. The pattern of bacterial resistance is important for epidemiological and clinical purposes [22] [25]. The results of the antimicrobial pattern give serious cause for concern because the predominant bacterial isolates were highly resistant to the commonly available antimicrobial agents [20] [26]. Our study revealed huge proliferation of bacteria in the burn wound samples studied, and traced a number of multi-drug resistant isolates despite the sex and degree of tissue damage of the patients. The results are in accordance with the contemporary studies and further implicate the necessity of stringent care in burn unit in hospitals. Routine monitoring of burn infections with antibiogram profile employing the primary experiments described here would be effective in delivering the detailed profile of burn wound prevailing microorganisms and hence would be implicative in context of overall public health management [21] [27] [28] [29] [30].

In conclusion, gram negative bacteria were the dominating bacteria all over the study period especially P.aeruginosa, most of which were multidrug resistant. Amikacin was the drug of choice for most gram negative bacteria and vancomycin was found to be effective against gram positive bacteria (S. aureus and coagulase negative Staphylococci). Present investigation seems to be helpful in providing useful guidelines for choosing effective therapy against isolates from burn patients. Huge bacterial onset with an alarming threat of multidrug resistance would potentially raise the necessity of proper care and management of burn wound patients in hospital.

The authors declare no conflicts of interest regarding the publication of this paper.

Fatema, K., Sultana, S., Ali, M.H., Akter, T., Khadiza-Tul-Kobra and Islam, S. (2021) Detection of Pathogenic Microorganisms from Burn Patients Admitted in Tertiary Medical College Hospital and Their Antimicrobial Patterns. Open Journal of Medical Microbiology, 11, 58-67. https://doi.org/10.4236/ojmm.2021.111005