INTRODUCTION 

Invasive burn wound infection is a critical issue characterized by the infiltration of microorganisms into burn wounds, potentially leading to pus formation and severe complications. The occurrence of invasive burn infections has significantly reduced over time. These advancements have not only altered the types of microorganisms involved but also extended the time from injury to infection onset, reducing the mortality rate associated with burn injuries caused by thermal energy. Prior to the introduction of topical antibacterial chemotherapeutic agents in the mid-1960s, invasive burn wound infection posed a significant threat, often resulting in fatal outcomes. The progress in managing invasive burn wound infections is commendable and has undoubtedly improved patient outcomes in burn care ¹. The severity of the burns, depending on the rate of separation of burn infections, is also determined by the age of the patient and the level of the burn. In partial-thickness wounds invasive burn infections occur rarely; occurrence was frequent in children, most frequent in the elders and a decrease in young adults (15 to 40 years old) ². The presence of coagulant proteins and microbial nutrients in the wound increases the susceptibility to infection stems on the burned surfaces. Additionally, the transportation of humoral factors, immune-active cells, and antibiotics necessary for combating infections is hindered by the avascular nature of the scab. This compromised delivery system contributes to the vulnerability of the wound to ulcer disease ³. The presence of flora in a burn area significantly impacts infection risk and invasiveness. Initially, post-burn wounds exhibit a low microbial population, primarily consisting of Gram-positive bacteria surviving in the skin adnexa. As time progresses, Gram-negative bacteria colonize the scab, becoming the predominant type in the burn wound after approximately one week. This transition underscores the importance of monitoring and managing microbial flora in burn injuries to mitigate infection risks effectively. ⁴. A hemolytic streptococcus-β was the most common cause of burns and dangerous systemic infections, but after the discovery of antibiotics, treatment with penicillin essentially eliminated the mortality rate ⁵. After treatment with penicillin, Staphylococcus aureus was identified as the most frequently encountered early Gram-positive pathogen in burn wounds ⁶. Pathogens have the capability to invaginate the squamous layer and infiltrate unburned subcutaneous tissue, forming multiple abscesses of varying sizes. While S. aureus typically does not cross tissue planes and can lead to the development of thickened abscess walls, compromising the efficacy of both host defenses and antibiotic treatments ⁷. Purplish discoloration dark-brown or present on the wound may vary in localization, appearing as a singular spot, scattered areas, or spreading throughout the entire system. This alteration could signal a shift from a partial-thickness injury to complete tissue necrosis ⁸. Patients commonly present with specific symptoms such as redness, swelling, and sensitivity of the no burned skin surrounding the burn or wound site can be observed ⁹. Without intervention, these symptoms may progressively spread, with some cases involving lymphatic involvement. An escalation in clear fluid discharge from the wound may be noted, and in instances where β-hemolytic streptococcal infection affects the skin graft. The graft could be rapidly compromised or sometimes deteriorating overnight ¹⁰. The higher concentrations of bacteria at an appropriate depth of the burn wound causes suppurative separation of the eschar or graft loss and finally invasive infection. In cases where sensitivity testing and culture assessments are unavailable, broad-spectrum antibiotics are typically employed to address cellulitis. Warm water baths are recommended for managing areas affected by cellulite. Additionally, applying “Mafenide Acetate Burn Cream” twice a day on the donor surface until the infection was under control. If the donor skin site remains unhealed, full-thickness lesions can undergo grafting, while biological dressings can be used for partial-thickness lesions to promote optimal conditions for bandage removal ¹¹. The important indicator of an invasiveness of the burn is the presence of a localized, multi localized, or generalized dark brown area and after while wound turns black or purple ¹². Skin exfoliation may be the first sign of midface mucositis, and its presence suggests retrobulbar fat biopsy ¹³. Heals vesicular lesions or heals second-degree burns as well as the presence of tooth edges and partial thickness crusts. Facial burns, especially nasolabial area, were indicative of burn infections caused by herpes simplex virus type-1 ¹⁴. Given that similar alterations in the wound can stem from various causes like wound desiccation, necrosis, pressure-induced necrosis, or hemorrhage (local trauma), an infection diagnosis should be made carefully. Surface cultures, which serve as another confirming method, prove valuable in identifying organisms present on the burn as well as the prevalent bacterial species in the burn area. However, even quantitative culture methods may not differentiate between burn colonization and infection ¹⁵. The lower bacterial count generally indicates the absence of burn infection, but a quantitative count ≥10 organisms/ gram of tissue is often associated with histological signs pointing towards invasive infection, observed in less than half of samples ¹⁶. Histological examination of a burn biopsy is the golden tool and an important way to confirm the diagnosis of infected burned patients more than culture examination and its limitations. In cases of viral infection due to burns, diagnosis can also be diagnosed with histological test of scratches resulting in skin lesions. Using antibiotics for systemic prophylaxis is common in burn patients ¹⁷. Resistant bacteria with intrinsic antibiotic resistance, longer survival in hospital environments, and contact transmission of bacteria causes their rapid and easy spread to cause epidemics ¹⁸. Extensively drug-resistant (XDR) and pan-drug-resistant (PDR) strains classified as non-susceptible to at least one agent in all. Two or fewer classes of antibiotics, and strains were non-susceptible to all antibiotics according to ECDC and CDC respectively ¹⁹. Therefore, this study aimed to investigate the causes of burns infection and antibiotics resistance.

MATERIALS AND METHODS

All medical records of burn patients hospitalized to the Burn Unit; Baquba Teaching Hospital, Diyala government hospital (Iraq), were examined from November 2022 to November 2023 retrospectively. Data on patient age, gender, and infection outcomes were documented. Treatment protocols for burns aligned with established international standards, encompassing antibiotic, daily wound care involving topical antibiotic like sulfadiazine, fluid resuscitation, nutritional support, resuscitation procedures, and surgical interventions such as resection and pressure grafting for ulcers. Fundamental measures within the burn unit aimed at burn care and infection prevention encompass practices like staff hygiene, room isolation, periodic ward area cultures, and visitor restrictions. During wound exchanges, samples were directly inoculated onto 5% blood agar and Eosin methylene blue (EMB) agar. The incubation of agar plates at 35±2°C for 18-24 hours under aerobic conditions ²⁰. Any observed bacterial growth patterns were meticulously documented, and the isolated bacteria were subsequently identified using conventional techniques. Among 100 burn patients with positive culture included 52 males and 48 females with mean age 39.17 years (15 -65 years) were selected for this study during the period. 

Mean total surface burned area was 18% and range from 12% to 83%.

RESULTS

The research consisted of 100 participants: 52 males and 48 females, as shown in Table-1 and Figure-1. The age ranged from 16-65 years, with the majority 46-65 age group as shown in Table-1 and Figure 2. The percentage of body surface area burned ranged from 12% to 83%. In the cultures studied, only one species per culture was studied. A gram-positive spherically shaped bacterium, Staphylococcus aureus; a short, rod-shaped gram-negative bacterium, Acinetobacter baumannii were found. This research showed the considerable variety of bacteria from the 100 wound swabs collected. The principal species were S. aureus, A. baumannii, and Klebsiella spp. The gram-negative, rod-shaped bacterium, Pseudomonas aeruginosa, spherical shaped gram-positive bacterium, Streptococcus pneumoniae, or pneumococcus, and rod-shaped coliform bacterium, Escherichia coli was isolated with less frequency as showed in Table-3 and Figure-3 and the bacterial isolates were shown. Body surface area of burned patients ranged between 12-83%.

Table 1: Gender of patients

Figure 1: Gender distribution of burn patients

Table 2: Age of patients

Figure 2: Age distribution of burn patients

Table 3: Type of bacteria present in burns

Various antibiotics were assessed concerning their effectiveness against gram-positive and gram-negative bacteria. The susceptibility of microorganisms to antibiotics varies among different isolates. Staphylococcus aureus exhibited the highest sensitivity to vancomycin (75.25%), whereas most of the isolated gram-negative bacterial strains displayed multidrug resistance. Resistance in S. aureus was noted at 40% to ciprofloxacin and 84% to erythromycin with all strains that were sensitive to vancomycin and ciprofloxacin in a minority of instances. Additionally, 40% of staphylococci isolated from samples were determined as MRSA. Figure-5 showed the bacteria responsible for burn infections, along with the antibiotics tested and their corresponding resistance profiles.

DISCUSSION

The drug spectrum and drug resistance of pathogenic isolates obtained from severely burned patients admitted in Baquba Teaching Hospital, Diyala government hospital (Iraq), were increased annually. However, better environmental control, use of contact precautions, and strictly enforced surgical care may be the reason for the low infection rate in admitted patients. Although survival after burn injury has improved significantly with improved treatments ²¹, control of infection remains a challenge. Several studies have sought to identify the most common multidrug-resistant pathogens, but the impact of multidrug-resistant organisms (MDROs) on survival and other outcome parameters remains unclear ^{22, 23}. Our goal was to shed light on this issue by examining 100 infected burn patients admitted to our burn unit. In 40.3% of cases, gram-positive cocci and in 55.7% gram-negative bacilli were identified. Pseudomonas emerged as the primary pathogen in our study, similar results from other research; however, it contrasts with studies, notably from developed nations, that pinpoint Staphylococcus aureus as the main organism. The universality of Pseudomonas infections in burn units may be reason to its preference for humid environments ^{24, 25}. Staphylococcus aureus and A. baumannii were the most frequently isolated pathogens in burn wounds in our study, followed by Klebsiella spp., Streptococcus, and E. coli. Proteus was present in 18.5% of cases, Antibiotic susceptibility profiles revealed widespread resistance to commonly used antibiotics due to indiscriminate usage over time. S. aureus displayed sensitivity to vancomycin and Gemifloxacin, while Pseudomonas and Klebsiella showed resistance to gentamicin and limited sensitivity to ciprofloxacin. In our research, a second-generation aminoglycoside, amikacin, showed the efficacy against Pseudomonas and Klebsiella ^{26, 27}.

The sensitivity of multiple pathogens to amikacin has been reported in previous research ^{28,29,30, 31}. The empiric use of broad-spectrum antibiotics and noncompliance with hospital antibiotic policies may be the reason for an increased rate of multi-drug-resistant isolates. Early discovering isolates is also important to avoid treatment misuse, as the time required to isolate, identify and detect antibiotic susceptibility can take up to 48 hours from the time of infection as it’s a sufficient time to allow a sub-clinical infection to become a life-threatening disease ^{32, 33, 34}. In case of burns, with mixed infections, the potential virulence of one organism can affect another organism may be another factor that increases the complications is multi-drug resistance (MDR). MDR strains can persist for many months, once established in a hospital environment ^{35, 36, 37}. 

Therefore, careful and precise microbiological monitoring and in vitro testing before starting of antibiotic therapy and a restrictive antibiotic policy can be of great help in the prevention and treatment of MDR isolates ^{38, 39}. Therefore, careful and precise microbiological monitoring and in vitro testing before starting of antibiotic therapy and a restrictive antibiotic policy can help to prevent and treatment MDR isolates ^{38, 39}. In burn units, overcrowding is a significant cause of cross-infection and can be avoided to control NI ^{40, 41,42}.

CONCLUSION 

It was found in this study that the low progression of nosocomial infection (NI) and a reduced rate of isolates resistant to some drugs that are rarely used in hospitals. These results suggest that widespread antibiotic use in burn patients may lead to high rates of infection-resistant pathogens. Therefore, antibacterial drugs must be used with caution, depending on the isolate and its antibiotic profile. Staphylococcus aureus is the main pathogen in burn wound infections, and A. baumannii is the second most common cause of infection in burned patients. 

Source of funding: Self-funded 

Ethical approval: The study was performed as per the guidelines mentioned on the Declaration of Helsinki. The verbal consent and analytical approval of all participants was maintained before specimen collection. All documents related to the study protocol and consent form were reviewed and approved by the Ethical Committee of Baquba Teaching Hospital, Diyala government hospital (Iraq).

Conflict of interests: The authors declare no conflict of interest.

Data Availability Statement: The data presented in this study are available on request from the corresponding author. 

REFERENCES 

1. Radzikowska-Büchner E, Łopuszyńska I, Flieger W, Tobiasz M, Maciejewski R, Flieger J. An overview of recent developments in the management of burn injuries. International journal of molecular sciences. 2023 Nov 15;24(22):16357. https://doi.org/10.3390/ijms242216357 PMid:38003548 PMCid:PMC10671630

2. Roy S, Mukherjee P, Kundu S, Majumder D, Raychaudhuri V, Choudhury L. Microbial infections in burn patients. Acute and Critical Care. 2024 May 24;39(2):214. https://doi.org/10.4266/acc.2023.01571 PMid:38863352 PMCid:PMC11167422

3. Mamun AA, Shao C, Geng P, Wang S, Xiao J. Recent advances in molecular mechanisms of skin wound healing and its treatments. Frontiers in Immunology. 2024 May 21;15:1395479. https://doi.org/10.3389/fimmu.2024.1395479 PMid:38835782 PMCid:PMC11148235

4. Macedo-Viñas M, Lucas A. Evolution of Microbial Flora Colonizing Burn Wounds during Hospitalization in Uruguay. Biomedicines. 2023 Oct 26;11(11):2900. https://doi.org/10.3390/biomedicines11112900 PMid:38001901 PMCid:PMC10669172

5. Roy S, Mukherjee P, Kundu S, Majumder D, Raychaudhuri V, Choudhury L. Microbial infections in burn patients. Acute and Critical Care. 2024 May 24;39(2):214. https://doi.org/10.4266/acc.2023.01571 PMid:38863352 PMCid:PMC11167422

6. Maitz J, Merlino J, Rizzo S, McKew G, Maitz P. Burn wound infections microbiome and novel approaches using therapeutic microorganisms in burn wound infection control. Advanced Drug Delivery Reviews. 2023 May 1;196:114769. https://doi.org/10.1016/j.addr.2023.114769 PMid:36921627

7. Linz MS, Mattappallil A, Finkel D, Parker D. Clinical impact of Staphylococcus aureus skin and soft tissue infections. Antibiotics 2023; 12: 557. 2023 https://doi.org/10.3390/antibiotics12030557 PMid:36978425 PMCid:PMC10044708

8. Saleh RM, Motib AS. Molecular detection of OprD and ExoA in Pseudomonas aeruginosa and antibiotics resistance. InAIP Conference Proceedings 2023 Mar 31 (Vol. 2475, No. 1). AIP Publishing. https://doi.org/10.1063/5.0103074

9. Ji S, Xiao S, Xia Z, Chinese Burn Association Tissue Repair of Burns and Trauma Committee, Cross-Straits Medicine Exchange Association of China. Consensus on the treatment of second-degree burn wounds (2024 edition). Burns & trauma. 2024;12:tkad061. https://doi.org/10.1093/burnst/tkad061 PMid:38343901 PMCid:PMC10858447

10. Beldon P. What you need to know about skin grafts and donor site wounds. Wound Essentials. 2007;2(1):149-55.

11. Greenhalgh DG, Kiley JL. Diagnosis and Treatment of Infections in the Burn Patient. European Burn Journal. 2024 Sep 4;5(3):296-308. https://doi.org/10.3390/ebj5030028 PMid:39599952 PMCid:PMC11544804

12. Markiewicz-Gospodarek A, Kozioł M, Tobiasz M, Baj J, Radzikowska-Büchner E, Przekora A. Burn wound healing: clinical complications, medical care, treatment, and dressing types: the current state of knowledge for clinical practice. International journal of environmental research and public health. 2022 Jan 25;19(3):1338. https://doi.org/10.3390/ijerph19031338 PMid:35162360 PMCid:PMC8834952

13. Gupta V, Agarwal S, Ramam M. Pseudolipomatosis Cutis: A Retrospective Case Series of Skin Biopsies Showing a Distinctive Vacuolar Artifactual Change. The American Journal of Dermatopathology. 2020 Sep 1;42(9):648-52. https://doi.org/10.1097/DAD.0000000000001621 PMid:32149836

14. Chaudhary FA, Ahmad B, Sinor MZ. The severity of facial burns, dental caries, periodontal disease, and oral hygiene impact oral health-related quality of life of burns victims in Pakistan: A cross-sectional study. BMC Oral Health. 2021 Dec;21:1-0. https://doi.org/10.1186/s12903-021-01923-3 PMid:34749722 PMCid:PMC8573980

15. Eriksson E, Liu PY, Schultz GS, Martins‐Green MM, Tanaka R, Weir D, Gould LJ, Armstrong DG, Gibbons GW, Wolcott R, Olutoye OO. Chronic wounds: Treatment consensus. Wound repair and regeneration. 2022 Mar;30(2):156-71. https://doi.org/10.1111/wrr.12994 PMid:35130362 PMCid:PMC9305950

16. Żwierełło W, Piorun K, Skórka-Majewicz M, Maruszewska A, Antoniewski J, Gutowska I. Burns: classification, pathophysiology, and treatment: a review. International journal of molecular sciences. 2023 Feb 13;24(4):3749. https://doi.org/10.3390/ijms24043749 PMid:36835171 PMCid:PMC9959609

17. Torres MJ, Peterson JM, Wolf SE. Detection of infection and sepsis in burns. Surgical infections. 2021 Feb 1;22(1):20-7. https://doi.org/10.1089/sur.2020.348 PMid:33021433

18. Bobate S, Mahalle S, Dafale NA, Bajaj A. Emergence of environmental antibiotic resistance: Mechanism, monitoring and management. Environmental Advances. 2023 Oct 1;13:100409. https://doi.org/10.1016/j.envadv.2023.100409

19. Magiorakos AP, Srinivasan A, Carey RB, Carmeli Y, Falagas ME, Giske CG, Harbarth S, Hindler JF, Kahlmeter G, Olsson-Liljequist BJ, Paterson DL. Multidrug-resistant, extensively drug-resistant and pandrug-resistant bacteria: an international expert proposal for interim standard definitions for acquired resistance. Clinical microbiology and infection. 2012 Mar 1;18(3):268-81. https://doi.org/10.1111/j.1469-0691.2011.03570.x PMid:21793988

20. Leininger DJ, Roberson JR, Elvinger F. Use of eosin methylene blue agar to differentiate Escherichia coli from other gram-negative mastitis pathogens. Journal of veterinary diagnostic investigation. 2001 May;13(3):273-5. https://doi.org/10.1177/104063870101300319 PMid:11482612

21. Motib AS, Wadi HH, Sabae SK. Antibiotic Sensitivity of Streptococcus Pneumoniae that Isolated from Different Pneumococcal Infections. Indian Journal of Forensic Medicine & Toxicology. 2020 Jul 1;14(3).

22. Gulumbe BH, Faggo AA. Epidemiology of Multidrug-resistant Organisms in Africa. Mediterr J Infect Microb Antimicrob. 2019 Jan;8(25):1-1. https://doi.org/10.4274/mjima.galenos.2019.2019.25

23. Jassim SH, Motib AS. Evaluation of Biofilm Formation in Klebsiella Pneumoniae and Antibiotic Resistance. Indian Journal of Forensic Medicine & Toxicology. 2021 Apr 1;15(2). https://doi.org/10.37506/ijfmt.v15i2.14901

24. Fatema K, Sultana S, Ali MH, Akter T, Islam S. Detection of pathogenic microorganisms from burn patients admitted in Tertiary Medical College Hospital and their antimicrobial patterns. Open Journal of Medical Microbiology. 2021 Feb 2;11(1):58-67. https://doi.org/10.4236/ojmm.2021.111005

25. Al-Azzawi MH, Alkalifawi EJ. Detection of Bacteria Causing Burn Infection Isolated from Several Hospitals in Baghdad. Ibn AL-Haitham Journal For Pure and Applied Sciences. 2023 Jul 20;36(3):1-8. https://doi.org/10.30526/36.3.3090

26.  Prajescu B, Gavriliu L, Iesanu MI, Ioan A, Boboc AA, Boboc C, Galos F. Bacterial species and antibiotic resistance-A retrospective analysis of bacterial cultures in a pediatric hospital. Antibiotics. 2023 May 26;12(6):966. https://doi.org/10.3390/antibiotics12060966 PMid:37370285 PMCid:PMC10294880

27. Duhaniuc A, Păduraru D, Nastase EV, Trofin F, Iancu LS, Sima CM, Dorneanu OS. Multidrug-Resistant Bacteria in Immunocompromised Patients. Pharmaceuticals. 2024 Aug 30;17(9):1151. https://doi.org/10.3390/ph17091151 PMid:39338313 PMCid:PMC11434862

28. Thy M, Timsit J-F, de Montmollin E. Aminoglycosides for the Treatment of Severe Infection Due to Resistant Gram-Negative Pathogens. Antibiotics. 2023; 12(5):860. https://doi.org/10.3390/antibiotics12050860 

29. Mohamed AA. Antimicrobial Resistance Rates in Gram-positive Uropathogens in Duhok city, Kurdistan Region of Iraq. medRxiv. 2023 Mar 1:2023-02. https://doi.org/10.1101/2023.02.26.23286459

30. Klastersky J, Odio W, Hensgens C. Comparison of amikacin and gentamicin. Clinical Pharmacology & Therapeutics. 1975 Mar;17(3):348-54. https://doi.org/10.1002/cpt1975173348 PMid:804370

31. Luo H, Xu L, Chen Y. Drug resistance and susceptibility of amikacin in children with extended-spectrum beta-lactamase-producing Enterobacterales: a systematic review with meta-analysis. Diagnostic Microbiology and Infectious Disease. 2023 Aug 1;106(4):115956. https://doi.org/10.1016/j.diagmicrobio.2023.115956 PMid:37290259

32. Muteeb G, Rehman MT, Shahwan M, Aatif M. Origin of antibiotics and antibiotic resistance, and their impacts on drug development: A narrative review. Pharmaceuticals. 2023 Nov 15;16(11):1615. https://doi.org/10.3390/ph16111615 PMid:38004480 PMCid:PMC10675245

33. Ture Z, Güner R, Alp E. Antimicrobial stewardship in the intensive care unit. Journal of intensive medicine. 2023 Jul 25;3(03):244-53. https://doi.org/10.1016/j.jointm.2022.10.001 PMid:37533805 PMCid:PMC10391567

34. Bashir N, Dablool AS, Khan MI, Almalki MG, Ahmed A, Mir MA, Hamdoon AA, Elawad MA, Mosa OF, Niyazov LN, Elkhalifa ME. Antibiotics resistance as a major public health concern: a pharmaco-epidemiological study to evaluate prevalence and antibiotics susceptibility-resistance pattern of bacterial isolates from multiple teaching hospitals. Journal of Infection and Public Health. 2023 Dec 1;16:61-8. https://doi.org/10.1016/j.jiph.2023.09.019 PMid:37880004

35. Tsolakidis S, Freytag DL, Dovern E, Alharbi Z, Kim BS, Houschyar KS, Reumuth G, Schäfer B, Rennekampff HO, Pallua N, Grieb G. Infections in burn patients: a retrospective view over seven years. Medicina. 2022 Aug 8;58(8):1066. https://doi.org/10.3390/medicina58081066 PMid:36013534 PMCid:PMC9412298

36. Levani Y, Wasito EB. Streptococcus mitis and Klebsiella pneumoniae Mixed Infection in Severe Burn Injury Patient. Journal of Pure and Applied Microbiology. 2024 Jun 1;18(2):867-72. https://doi.org/10.22207/JPAM.18.2.53

37. Roy S, Mukherjee P, Kundu S, Majumder D, Raychaudhuri V, Choudhury L. Microbial infections in burn patients. Acute and Critical Care. 2024 May 24;39(2):214. https://doi.org/10.4266/acc.2023.01571 PMid:38863352 PMCid:PMC11167422

38. Yamin D, Uskoković V, Wakil AM, Goni MD, Shamsuddin SH, Mustafa FH, Alfouzan WA, Alissa M, Alshengeti A, Almaghrabi RH, Fares MA. Current and future technologies for the detection of antibiotic-resistant bacteria. Diagnostics. 2023 Oct 18;13(20):3246. https://doi.org/10.3390/diagnostics13203246 PMid:37892067 PMCid:PMC10606640

39. Yamin D, Uskoković V, Wakil AM, Goni MD, Shamsuddin SH, Mustafa FH, Alfouzan WA, Alissa M, Alshengeti A, Almaghrabi RH, Fares MA. Current and future technologies for the detection of antibiotic-resistant bacteria. Diagnostics. 2023 Oct 18;13(20):3246. https://doi.org/10.3390/diagnostics13203246 PMid:37892067 PMCid:PMC10606640

40. Norbury W, Herndon DN, Tanksley J, Jeschke MG, Finnerty CC, Scientific Study Committee of the Surgical Infection Society. Infection in burns. Surgical infections. 2016 Apr 1;17(2):250-5. https://doi.org/10.1089/sur.2013.134 PMid:26978531 PMCid:PMC4790211

41. Ariyo DA, Olorunfemi O. Infection control and prevention in burn victims: The role of nurses. Journal of Integrative Nursing. 2024 Apr 1;6(2):136-41. https://doi.org/10.4103/jin.jin_139_23

42. Hameed ZR, Motib AS, Abbas AF. Adaptability of Biofilm Formation in Streptococcus Pneumoniae to Various Growth Conditions. Indian Journal of Forensic Medicine & Toxicology. 2021 Apr 1;15(2). https://doi.org/10.37506/ijfmt.v15i2.14931