|Year : 2021 | Volume
| Issue : 1 | Page : 27-33
Evaluation of antibiotic usage in skin and soft-tissue infections and its antimicrobial susceptibility testing: A hospital-based cross-sectional study
Mohammed Fareedullah1, Zareen Unnisa1, Shajiya Khan1, Fakeha Fatima1, Afifa Khan1, Syed Nusrath Farees2, Mohammed Khaleel3
1 Department of Pharmacy Practice, Deccan School of Pharmacy, Hyderabad, Telangana, India
2 Department of General Surgery, Owaisi Hospital & Research Center, Hyderabad, Telangana, India
3 Department of Microbiology, Deccan College of Medical Sciences, Hyderabad, Telangana, India
|Date of Submission||16-Oct-2020|
|Date of Decision||19-Mar-2021|
|Date of Acceptance||12-May-2021|
|Date of Web Publication||29-May-2021|
Mr. Mohammed Fareedullah
Department of Pharmacy Practice, Deccan School of Pharmacy, Hyderabad 500001, Telangana.
Source of Support: None, Conflict of Interest: None
Aim: To evaluate the antibiotic usage in skin and soft-tissue infections (SSTIs) and to study the sensitivity pattern of identified microorganisms from antimicrobial susceptibility testing (AST) data. Materials and Methods: This was a cross-sectional study carried out in the Inpatient Department of General Surgery at Owaisi Hospital & Research Center, Hyderabad, for 6 months to collect 50 swab samples aseptically from the subjects with diverse SSTIs at the day of admission before the administration of antibiotics, and AST was done using Kirby Bauer disc diffusion method based on the guidelines of Clinical Laboratory Standard Institute (CLSI). Results: Of the 50 swab samples, 43 were culture positive and 7 were culture negative, and the highest number of cases was of cellulitis (14.28%). The most commonly isolated pathogen was Staphylococcus aureus (30.23%). On the basis of antibiotic sensitivity testing, we found that Ciprofloxacin was the most potent drug, followed by Ceftriaxone and Amikacin, for overall bacterial isolates. In our study, the treatment adhered to IDSA guidelines in 50% of cases and we found that many antibiotics were resistant. In cases of gangrene and abscess, a striking deviation from the guidelines (60% and 77.7%, respectively) was seen. Conclusion: This study guided us toward an appropriate treatment plan for the management of some SSTIs. The disproportionate and tedious use of antibiotics should be abstained as this may drive the evolution of resistant microorganisms that are even more difficult to get rid of.
Keywords: Antibiotics, antimicrobial susceptibility testing (AST), resistance, skin and soft tissue infections (SSTIs)
|How to cite this article:|
Fareedullah M, Unnisa Z, Khan S, Fatima F, Khan A, Farees SN, Khaleel M. Evaluation of antibiotic usage in skin and soft-tissue infections and its antimicrobial susceptibility testing: A hospital-based cross-sectional study. J Health Res Rev 2021;8:27-33
|How to cite this URL:|
Fareedullah M, Unnisa Z, Khan S, Fatima F, Khan A, Farees SN, Khaleel M. Evaluation of antibiotic usage in skin and soft-tissue infections and its antimicrobial susceptibility testing: A hospital-based cross-sectional study. J Health Res Rev [serial online] 2021 [cited 2021 Jun 19];8:27-33. Available from: https://www.jhrr.org/text.asp?2021/8/1/27/317215
| Introduction|| |
Skin and soft-tissue infections (SSTIs) can also be ascribed as skin and structure infections that encompass a class of infections distinct in their etiologies and severities, which generally stand in need of judicious use of medication and hospitalization. SSTIs involve microbial invasion of the epidermis, dermis, superficial fascia, subcutaneous tissues, and muscle in an increasing form of severity. The clinical presentation of SSTIs is the pinnacle of a two-step process that includes invasion of microbes and interaction of microbes with the host defenses. The primary clinical presentation of SSTIs is inflammatory response with other signs and symptoms like pyrexia, bullae, and lesions, which results in the production of pus.,
The wound infections are usually caused by both aerobic and anaerobic bacteria that are mostly found under hospital surveillance resulting in increased death rate, prolonged length of stay, and huge financial burden. Bacterial resistance is thus becoming a grave problem globally. Bacterial resistance including multi-drug resistance occurs mostly when the patients are given empirical antibiotic therapy. Thus, antibiotic resistance patterns should be monitored to prevail these difficulties and to reduce the occurrence of serious infections in hospitals.
Due to rapid development of resistance, bacterial strains like methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE), and extended-spectrum β-lactamase (ESBL) are posing a great threat to the primary healthcare providers globally for treating SSTIs, and also the basic antibiotic therapy given to the patients is usually empiric. Therefore, it is vital to know the sensitivity pattern of isolated bacteria causing SSTIs by performing antimicrobial sensitivity testing, to impart appropriate antimicrobial therapy for regulating infection, prevent morbidity, and improve quality of life.
Considering these facts, the present study was aimed to evaluate the antibiotic usage for the treatment of SSTIs and to study the sensitivity pattern of identified microorganisms from the antimicrobial susceptibility testing (AST) data.
| Materials and Methods|| |
Setting and design
This is a cross-sectional study carried out in the Inpatient Department of General Surgery at Owaisi Hospital & Research Center, Hyderabad, for 6 months to collect 50 swab samples aseptically from the SSTIs of the subjects at the day of admission before the administration of antibiotics. Sample collection was done as per the standard guidelines.
Inclusion criteria were SSTIs such as cellulitis, diabetic foot, gangrene, infective ulcers, and abscess, and patients aged above 12 years. Exclusion criteria were patients not willing to participate and patients who were given antibiotics before sample collection. During sample collection, standard care was maintained to circumvent the surface contamination. Within a period of 60min of sample collection, the samples were carried to a microbiology laboratory to perform culture and sensitivity tests. Consequently, inoculation of each specimen on a proper agar media was done followed by incubation of cultures aerobically at 37°C for 24–48h with supreme care.
All the plates were observed for bacterial growth, and methods such as colony morphology, Gram staining, and standard biochemical test were carried out to detect the isolated bacteria. Antibiotics used for the disc diffusion method includes Amikacin, Amoxicillin, Azithromycin, Aztreonam, Cefixime, Cefotaxime + Clavulanate, Ceftriaxone, Cefuroxime, Ciprofloxacin, Clindamycin, Linezolid, Meropenem, Piperacillin + Tazobactum, Vancomycin. Based on their inhibition zones, the isolates were considered to be susceptible or resistant. Data were analyzed using the SPSS (version 20) software. A P-value of <0.05 is considered significant because the CI is 95%.
| Results|| |
Characteristics of study participants
The mean age of the participants was 50 or more years and 70% of the subjects were male [Table 1] and [Figure 1]. The isolation rate of bacteria was 86% and only 14% showed no growth of bacteria in the culture plates [Table 2] and [Figure 2]. Around 53% of culture-positive plates (n = 43) were Gram negative, and 47% were Gram positive [Figure 3]. Of the 43 culture-positive samples, bacterial resistance was found in 36 samples toward the empirical treatment given [Table 3] and [Figure 4]. Disease-wise distribution of 50 samples collected shows that the highest number of samples collected were of cellulitis (28%) followed by diabetic foot infections (20%) [Table 4] and [Figure 5]. In this study, single antibiotic administration was predominant in 58% of patients [Table 5] and [Figure 6] and [Figure 7].
|Table 5: Comparison of the number of antibiotics prescribed between gender|
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|Figure 6: Comparison of the number of antibiotics prescribed between gender|
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|Figure 7: Correlation between age and number of antibiotics prescribed. y= 0.0333 * x + 0.3333, r= -0.112. A significant inverse correlation was found between age and the number of antibiotics|
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Isolation of different types of bacteria
S. aureus (n = 13, 30.23%) was found to be predominant among all the isolated bacteria. The frequency of Pseudomonas aeuroginosa and Klebsiella pneumonia was found to be 16.27% and 11.62%, respectively [Figure 8].
MRSA strains also accounted for 11.62% and MRSA was mostly sensitive to linezolid, vancomycin, cefpodoxime followed by cefuroxime, ceftriaxone, ceftriaxone + sulbactam, and amoxicillin, and the resistant strain was amoxyclav.
Sensitivity pattern of Gram-positive and Gram-negative bacteria
The Gram-positive bacteria was mostly sensitive to vancomycin (82.5%), supersede by linezolid (75.5%), and cefuroxime and ceftriaxone + sulbactam (72.5%); other antibiotics, less than 70% [Table 6].
|Table 6: Sensitivity patterns of isolated Gram-positive bacteria (n = 19)|
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Majority of the isolated Gram-negative bacteria were sensitive to aztreonam (80%), piperacillin + tazobactam (72.3%), and cefepime (60.6%) [Table 7].
|Table 7: Sensitivity patterns of isolated Gram-negative bacteria (n = 17)|
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Concordance/discordance between guidelines and practice
We examined the degree to which the clinicians in a teaching hospital stand by with the standard guidelines (IDSA) for the treatment of SSTIs. On the basis of the selection of antibiotics, we found that treatment fully adhered to the guidelines in 50% of cases. In cases of gangrene and abscess, a striking deviation from the guidelines (60% and 77.7%, respectively) was seen. Where as in cases of diabetic foot, cellulitis, and ulcers, it was found to be 40%, 38%, & 50%, respectively [Table 8] and [Figure 9].
| Discussion|| |
SSTIs are common complications occurring in both inpatient and out-patient departments in the hospital. They may vary from simple, uncomplicated, superficial infections such as cellulitis, and abscess to deeper complicated infections such as diabetic foot. Complicated SSTIs lead to prolonged hospital stays, rise in the cost of medical care, and are likely to have a crucial role in the development of antimicrobial resistance. The most frequent organisms involved in SSTIs are Gram-positive cocci, S. aureus.
In this study, male patients were predominant with a male:female ratio of 7:3, and this finding was in contrast to the other studies where the number of female patients was much higher than males. The most common causative microorganism for SSTIs worldwide with a prevalence rate ranging from 4.6% to 54.4% is S. aureus.S. aureus was the dominant microorganism (30.23%) in this study, and these data were persistent with the results of other studies.,,,, The predominant role in hospital-associated infection and emergence of MRSA strains is of special interest in S. aureus infections. In our study, we found that 11.62% of S. aureus isolates were resistant to methicillin and also all the S. aureus strains (irrespective of MRSA) were sensitive to vancomycin and linezolid. These data can be of significant clinical use for selecting appropriate antibiotics against resistant strains.
53.4% of all the aerobic bacterial isolates were Gram-negative microorganisms. Pseudomonas aeuroginosa (30.4%) was the most common Gram-negative bacteria isolated, superseded by Klebsiella pneumonia (21.7%), normal endogenous microbial fecal flora.
For majority of the bacterial isolates, AST results impart a high grade of resistance. For Gram-positive bacteria, cefoxitin, azithromycin, ceftriaxone, and cefuroxime were found to be the most efficacious antibiotics whereas the most common resistant drugs were amoxicillin + clavulanate, ceftriaxone, and ciprofloxacin. Staphylococcus aureus strains isolated in the present study were found to be highly resistant in comparison to the previous studies.
Prophylactic antimicrobials were given to all cases upon admission after sample collection in our study. The most widely used combination was amoxicillin + clavulanate. However, the isolated bacteria were mostly resistant to this agent as per the AST results.
In our study, we examined the degree to which the clinicians in a teaching hospital adhere to standard guidelines for the management of SSTIs and we found that treatment fully adhered with IDSA guidelines in 50% of cases, out of which many antibiotics were found to be resistant when compared to that found in the study done by Kamath et al. where the management was in consonance with the guidelines in 20.1% of the cases.
The spread and development of MDR strains have evolved as a universal problem and has been marked as an imminent genetic response to the strong selective pressure levied by the antibacterial therapy that plays a vital role in the evolvement of resistant strains. Thus, it is important to monitor continuously the sensitivity patterns of isolated bacteria by performing laboratory AST in the hospital setting to uncover the actual burden of antibiotic resistance and to avoid their future emergence by making the drug selection more rational.
Primarily the sample size of this study was small; a large sample size would make the study more transparent. Furthermore, this study was conducted at a single center; a multicenter study would have produced more significant results, covering a wide range of bacteria present in different locations. Hence, future studies should consider these variables.
| Conclusion|| |
The majority of the patients received parenteral antibiotic therapy. Adverse drug reactions were minor and well managed. Empirical antibiotic treatment was found to be resistant in 70% of patients and interventions required to correct the use of sensitive antibiotics. Prescribers rely more on their experience for selecting the appropriate antibiotics. The presence of MRSA organism was alarming in 10% of patients. The increasing trend of resistance to β-lactams is leading to a great problem.
Data obtained from this study proposed that large prospective studies are a prerequisite to assess the suitable empirical antibiotic regimen in the treatment of diabetic foot, cellulitis, ulcer infections, etc. This study directed us toward appropriate treatment strategies for the management of cellulitis, ulcers, diabetic foot with appropriate antibiotics such as Ceftriaxone followed by Amikacin. And the most resistant drugs were found to be Clindamycin followed by Ciprofloxacin. The disproportionate and tedious use of antibiotics should be abstained as this may drive the evolution of resistant microorganisms that are even more difficult to get rid of. This study shows a striking lack of concordance with IDSA guidelines in the treatment of SSTIs. In only 50% of cases, antibiotics as per the treatment guidelines were prescribed; out of which, many antibiotics were found to be resistant. Thus, AST is a crucial parameter for choosing an appropriate antibiotic and reducing antibiotic resistance to overcome bacterial antibiotic resistance.
Antimicrobial resistance is increasing rapidly globally. Multidrug-resistant organisms are emerging and spreading in all parts of the world posing a great challenge to the primary healthcare practitioner’s ability to treat SSTIs. Hence, it is important to monitor continuously the susceptibility patterns of isolated bacteria by performing laboratory AST in a hospital setting to uncover the actual burden of antibiotic resistance and to avoid their future emergence by making the drug selection more rational.
Financial support and sponsorship
Conflicts of interest
Data availability statement
All the relevant data are available.
This study was conducted after obtaining the approval from Institutional Review Board of the teaching hospital in India. Informed consent was obtained from each participant.
FM: Conceptualization, project administration, and supervision. ZU, SK, FF, AK: Collection of patient data, sample for CST and Informed consent, draft preparation, editing, and analyzing results. SNF: Sample identification, methodology, and validation. MK: Investigations, formal analysis.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8], [Figure 9]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6], [Table 7], [Table 8]