|Year : 2018 | Volume
| Issue : 1 | Page : 13-18
Bacteriological study of community-acquired pyoderma with special reference to methicillin-resistant Staphylococcus aureus
Neetha Thomas, Banavasi Shanmukha Girisha
Department of Dermatology, K S Hegde Charitable Hospital, Mangalore, Karnataka, India
|Date of Web Publication||5-Jan-2018|
Banavasi Shanmukha Girisha
Department of Dermatology, K S Hegde Charitable Hospital, OPD Number 4, Deralakatte, Mangalore - 575 018, Karnataka
Source of Support: None, Conflict of Interest: None
Background: Pyoderma is one of the most frequently encountered condition in dermatology clinics in India. Staphylococcus and Streptococcus are the most common causative agents. There is considerable variation in the reported antibiotic susceptibility pattern of the organisms isolated from pyoderma with a trend toward increasing resistance. Objectives: The objectives of this study were (1) to study the clinical patterns of cutaneous bacterial infections, (2) to determine the antibiotic sensitivity of the isolates obtained, and (3) To assess the prevalence of methicillin resistance (methicillin-resistant Staphylococcus aureus [MRSA]) among the community–acquired (CA) pyoderma. Materials and Methods: Two hundred and fifty-six patients of CA pyoderma constituted the study population. A detailed history was taken and thorough clinical examination was performed. Gram-stained smear examination and culture and sensitivity test of pus were done. Results: Primary pyoderma was seen in 48.8% and secondary pyoderma in 51.2% of cases. The most common primary pyoderma was folliculitis (52%) followed by furuncle (25.6%). In secondary pyoderma, the most common condition was infected eczema (38.2%) followed by infected ulcers (22.1%). Staphylococcus was isolated in 87.5%, Streptococcus in 2%, and mixed organisms were isolated in 5.5% of cases. Maximum susceptibility was seen to tigecycline (89.1%) and linezolid (88.3%). Among topical antibiotics, mupirocin was susceptible in 75.8% and fusidic acid in 66.4% of the organisms. The highest resistance was seen to benzylpenicillin in 81.6% followed by ciprofloxacin in 53.1% of the organisms. The least resistance was seen for daptomycin in 0.8%, tigecycline in 1.6%, linezolid in 2.3%, and mupirocin in 2.7% of the organisms. The proportion of MRSA in CA pyodermas was 25.5%. Conclusion: The study yielded some useful epidemiological and clinicobacteriological data about CA pyoderma. The above observations made regarding antibiotic sensitivities may assist clinicians in choosing antibiotics for CA pyoderma in the absence of pus culture sensitivity.
Keywords: Bacterial resistance, furunculosis, topical antibiotics
|How to cite this article:|
Thomas N, Girisha BS. Bacteriological study of community-acquired pyoderma with special reference to methicillin-resistant Staphylococcus aureus. Clin Dermatol Rev 2018;2:13-8
|How to cite this URL:|
Thomas N, Girisha BS. Bacteriological study of community-acquired pyoderma with special reference to methicillin-resistant Staphylococcus aureus. Clin Dermatol Rev [serial online] 2018 [cited 2018 Apr 20];2:13-8. Available from: http://www.cdriadvlkn.org/text.asp?2018/2/1/13/222268
| Introduction|| |
Pyoderma may present in two forms - primary and secondary pyodermas. The organisms causing these infections differ based on the type of lesions. Staphylococcus and Streptococcus are the most common causative agents, and occasionally, few Gram-negative organisms may also be a cause of pyoderma. There is considerable variation in the reported antibiotic susceptibility pattern of the organisms isolated from pyoderma with a trend toward increasing resistance. Methicillin-resistant Staphylococcus aureus (MRSA), which was once considered a nosocomial pathogen, is being increasingly reported as a colonizer in healthy individuals without any risk factors, and even in community-acquired (CA) infections including pyoderma. The first case report of MRSA was in the United States in the year 1968. MRSA is defined as isolates with a methicillin minimum inhibitory concentration ≥4 μg/mL. Methicillin resistance to S. aureus is mediated by mecA gene which encodes a novel altered penicillin-binding protein-2A which induces resistance to all β-lactam antibiotics including cephalosporins. The emergence of antibiotic resistance has significantly deteriorated the utility of well-established antibiotics and poses a serious threat to the public health. It is, therefore, essential to determine the sensitivity pattern of the clinical isolates of S. aureus in different communities across the country.
| Materials and Methods|| |
This hospital-based study was conducted in the outpatient Department of Dermatology in a tertiary care hospital attached to K S Hegde Medical academy, Mangalore, from October 2014 to April 2016. Ethical clearance was obtained from the Institutional Ethics Committee. Two hundred and fifty-six patients with primary or secondary pyoderma attending the outpatient department were selected consecutively. The study included all patients of CA pyoderma irrespective of age and gender who consented for the study. Patients who had used any topical application, systemic antibiotics, and a history of hospital stay in the past 1 month were excluded from the study. A detailed history was taken with special reference to the mode of onset, history of contact, type of lesion, duration, distribution, and progression of lesions. Thorough clinical examination was performed to find out the distribution of primary lesions, secondary changes, lymph nodes, systemic illness, general health, and personal hygiene of the patients.
A sample of pus was collected on two sterile swabs after cleaning of the lesions with normal saline. In case of intact pustular lesions, the pustule was ruptured with a sterile needle and material was collected on two sterile swabs. In case of crusted lesions, the crusts were partly lifted, and the material was collected from underneath. One of the swabs was used to a make a thin smear on a clean glass slide. This was used for Gram-staining and examination. The other swab was sent for culture and sensitivity studies.
Antibiotic susceptibility was tested using automated culture system, VITEC II, and it was interpreted according to the Clinical and Laboratory Standard Institute guidelines. Susceptibility of the isolates to fusidic acid and mupirocin was tested using Kirby–Bauer disc diffusion method. S. aureus ATCC 25923 was used as a control. The collected data were statistically analysed using SPSS software IBM SPSS Statistics, version 20 (Armonk, NY: IBM Corp). Chi-square test was used to see the goodness to fit for the sensitivity of each antibiotic to Staphylococcus.
| Results|| |
The present study comprised of 63.7% males and 36.3% females and the male to female ratio was 1.75:1. The youngest patient was 17 days old and the oldest was 75 years. Most of the pyoderma was seen to occur on the lower limbs (52%), followed by lesions over multiple sites (19.9%), on head and neck (12.5%), on the trunk and upper limb (7%), and on the genitalia (1.6%). Gram staining of the pus showed Gram-positive cocci in 89.5%, Gram-negative bacilli in 1.5%, both Gram-positive and Gram-negative bacteria (mixed organisms) in 3.2%, and only pus cells and no organism in 5.9% of the smears. Clinical profile of pyoderma and their distribution with respect to age group are given i[[Table 1]. Details of the Gram staining characteristics are given in [Table 2].
|Table 2: Clinical profile of pyoderma and their distribution with respect to age group|
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Impetigo was common in the age group of <1–10 years, folliculitis between 20 and 50 years, and furunculosis in all age groups. Dermatitis cruris pustulosa et atrophicans (DCPA) occurred more commonly in the third and fourth decade. Secondary pyoderma occurred in all age groups, being more common in the first three decades [Figure 1],[Figure 2],[Figure 3],[Figure 4] depict furuncle, infected eczema with secondary impetiginization, ecthyma and folliculitis respectively. Recurrence of the pyoderma over the past 1 year was seen in 99 patients (38.7%) with most of the recurrences seen in folliculitis, infected eczemas, and furunculosis.
The prevalence of diabetes mellitus among the study population was 18.8% and most commonly associated with furunculosis. In the present study, organisms were isolated in 241 (94.1%) patients, of which single organism was isolated in 227 (88.2%) and more than one organism in 14 (5.5%). No growth was seen in 15 (5.9%) of the total patients. The bacteria isolated from pyoderma are depicted in [Table 3]. The isolated organisms were maximally susceptible to tigecycline (89.1%) followed by linezolid (88.3%). Among topical antibiotics, mupirocin was susceptible in 75.8% and fusidic acid in 66.4% of the organisms. The isolated organisms showed the highest resistance to benzylpenicillin in 209 (81.6%), followed by ciprofloxacin in 136 (53.1%) and erythromycin in 99 cases (38.7%). Resistance to second-line or newer antibiotics such as daptomycin (0.8%), tigecycline (1.6%), and linezolid (2.3%) was also noted. The susceptibility pattern of various antibiotics is shown in [Table 4]. The proportion of MRSA among the S. aureus isolates obtained from the cases of CA pyoderma was 25.5%.
| Discussion|| |
In the present study, majority of pyoderma occurred in the second and third decades. Amarjeet Singh et al., in their study conducted in Jaipur, on 100 cases of pyoderma, had maximum incidence in the second and the third decade. Nagaraju et al., on 250 patients of CA pyoderma, found that about 50% of the cases occurred under the age of 10 years, followed by second and third decade. Pyoderma was more common in males with a male to female ratio of 1.75:1. Amarjeet Singh et al. reported an incidence of 72% in male patients. The present study showed an occurrence of pyoderma in males up to 63.7% which closely correlated with the observation of Ghadage and Sali, who reported 62.5%. Venniyil et al. reported a male predominance with 64.35% males and 35.7% females in their study subjects., This predominant male distribution in pyoderma may be due to occupational factors. Most of the patients were not aware of the source of contact. Contact with a family member with pyoderma was seen in 4.3%, contacts at school and hospital accounted for 3.1% each. In the present study, most of the pyoderma was seen to occur on the lower limbs (52%) followed by lesions on head and neck in 12.5%, on the trunk and upper limb in 7%, and on the genitalia in 1.6% of cases. Multiple sites were involved in 19.9% of the patients.
The present study showed that 59% of the patients belonged to the middle class followed by the low socioeconomic strata based on the Kuppuswamy's scale for socioeconomic status. Mathew et al., in their study of 120 children with pyoderma, found that almost all the children were from lower socioeconomic strata. Nagmoti et al. found majority belonging to lower socioeconomic status in 69%, middle in 27%, and higher in 4% of the patients, respectively.
In the present study, 125 cases (48.8%) constituted primary pyodermas and 131 cases (51.2%) constituted secondary pyodermas. Most of these were caused by S. aureus (82.8%) which closely correlates with the study by Patil et al. (81.4%) and Nagaraju et al. (80.8%). Nagaraju et al. found primary pyoderma and secondary pyoderma in 68.8% and 31.2% cases, respectively. Among primary pyoderma, impetigo was the most common (29.6%), followed by ecthyma (13.6%) and folliculitis (11.6%) in their study.
Patil et al. found that folliculitis (58.9%) was the most common primary pyoderma followed by furuncles (33.3%). These findings are similar to the present study. Bhaskaran et al. found that folliculitis (25.90%), impetigo (16%), and furuncle (4%) were the primary pyoderma in their study. Organisms were isolated in 241 (94.1%) patients, of which single organism was isolated in 227 (88.2%) and more than one organisms in 14 cases (5.5%). No growth was seen in 15 (5.9%) of the total patients. Baslas et al. reported single organism in 75.90% and more than one in 24.10% of his study subjects. The most common organisms isolated were S. aureus, beta-hemolytic streptococci either alone or in combination with others. Maximum susceptibility of the organisms was to tigecycline (89.1%) followed by linezolid (88.3%). Among topical antibiotics, most susceptibility was noted to mupirocin in 75.8% and fusidic acid in 66.4% cases, respectively. Several studies spanning from 1980 to 2016 have reported penicllin susceptibility from 39% to 0%.,,,,, Nagaraju et al. also reported resistance to erythromycin (56.6%) and co-trimoxazole in 27.2% in their study.
Furtado et al. in their study found that CA pyoderma showed maximum resistance to penicillin (85.4%), followed by ciprofloxacin (40%) and erythromycin (31.4%), a pattern similar to the present study. Among the S. aureus isolated, 25.5% were MRSA in our study which is higher than 11.3% and 10.9% found by Furtado et al. and Nagaraju et al., respectively., As these two studies are done in the same geographic region as our study, we are seeing an increasing trend of MRSA causing pyoderma. Soumya Rani et al., in 2016, reported a 13% of MRSA from the pyoderma from the neighboring state of Kerala. Studies from North India show a lower detection of MRSA, as demonstrated by Patil et al. and Thind et al. They reported 1.4% and 9.6% detection of MRSA in their study, respectively., A Recent study by Venniyil et al. in 2016 also detected relatively high MRSA (21.98%), which correlates with our study. This increased trend of MRSA can be attributed to the indiscriminate and inappropriate use of antibiotics and the strategy of eliminating nasal carrier rates by administering topical antibiotics. Furthermore, the new entity of community-onset hospital-acquired MRSA, where the gene encoding corresponds to hospital-acquired MRSA strain but with an onset of infection within the community may also have contributed. Resistance to methicillin is coded by mec gene which is represented on the staphylococcal chromosomal cassette mec (SCC mec). SCC mec I-III are large and are responsible for multidrug resistance. These have been associated with hospital-acquired MRSA. Smaller chromosomal cassettes, SCC mec IV and SCC mec V, are associated with CA MRSA and they do not code for drug resistance. Panton–Valentine leukocidin (PVL) is a two-component S. aureus pore-forming protein encoded by lukF and lukS genes. It is mostly associated with CA MRSA. PVL is cytotoxic to neutrophils and inactivate mitochondria. Phenol-soluble modulin alpha peptides, alpha toxin along with PVL, are found to be responsible for the virulence of CA MRSA in animal infection models., Another matter of concern noted in our study was significant resistance to second-line or newer antibiotics such as vancomycin (4.3%), daptomycin (4.3%), linezolid (2.3%), tigecycline (1.6%), and teicoplanin (0.8%).
As MRSA is multidrug resistant, it is important to prevent its epidemic. A Recent study found that improved hand hygiene was able to decrease new healthcare-acquired MRSA cases to about 67%. It also suggested combined interventions such as standard precautions, contact precautions, universal screening for MRSA, and decolonization of cases, for effective control of MRSA.
| Conclusion|| |
This study of 256 patients of pyoderma during the year 2014–2016 yielded some useful information regarding the bacterial resistance patterns prevalent in CA pyoderma. MRSA was detected in 25.5% cases of Staphylococcus-induced CA pyoderma. The isolated organisms showed maximum susceptibility to tigecycline (89.1%) followed by linezolid (88.3%). Among topical antibiotics, organisms were more susceptible to mupirocin (75.8%) than fusidic acid (66.4%). The isolated organisms showed higher resistance to common antibiotics such as benzylpenicillin (81.6%), ciprofloxacin (53.1%), and erythromycin (38.7%). The emergence of antibiotic resistance has significantly reduced the utility of well-established antibiotics. Periodic sensitization of the general medical practitioners regarding the sensitivity pattern prevalent in their respective communities should be the need of the hour to prevent the indiscriminate use of antibiotics and the development of antibiotic resistance.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]
[Table 1], [Table 2], [Table 3], [Table 4]