Seasonal occurrence of impetigo: a retrospective 8-year review (1996-2003)

Emergence and spread of a mupirocin-resistant variant of the European epidemic fusidic acid-resistant impetigo clone of Staphylococcus aureus, Belgium, 2013 to 2023

BackgroundAntimicrobial resistance to mupirocin and fusidic acid, which are used for treatment of skin infections caused by Staphylococcus aureus, is of concern.AimTo investigate resistance to fusidic acid and mupirocin in meticillin-susceptible S. aureus (MSSA) from community-acquired skin and soft tissue infections (SSTIs) in Belgium.MethodsWe collected 2013-2023 data on fusidic acid and mupirocin resistance in SSTI-associated MSSA from two large Belgian laboratories. Resistant MSSA isolates sent to the Belgian Staphylococci Reference Centre were spa-typed and analysed for the presence of the eta and etb virulence genes and the mupA resistance gene. In addition, we whole genome sequenced MSSA isolates collected between October 2021 and September 2023.ResultsMupirocin resistance increased between 2013 and 2023 from 0.5-1.5% to 1.7-5.6%. Between 2018 and 2023, 91.4% (64/70) of mupirocin-resistant isolates were co-resistant to fusidic acid. By September 2023, between 8.9% (15/168) and 10.1% (11/109) of children isolates from the two laboratories were co-resistant. Of the 33 sequenced isolates, 29 were sequence type 121, clonal and more distantly related to the European epidemic fusidic acid-resistant impetigo clone (EEFIC) observed in Belgium in 2020. These isolates carried the mupA and fusB genes conferring resistance to mupirocin and fusidic acid, respectively, and the eta and etb virulence genes.ConclusionWe highlight the spread of a mupirocin-resistant EEFIC in children, with a seasonal trend for the third quarter of the year. This is of concern because this variant is resistant to the two main topical antibiotics used to treat impetigo in Belgium.

Impetigo incidence and treatment: a retrospective study of Dutch routine primary care data

BACKGROUND

There is a lack of recently published data on impetigo presentation incidence and treatment practices in the routine Western European primary care setting.

OBJECTIVES

To investigate impetigo incidence, treatments and recurrence in primary care in the Netherlands.

METHODS

A retrospective, observational study. Electronic records of patients treated for impetigo in 2015 at 29 general practices in Utrecht and surrounds were reviewed. An episode of impetigo was defined as one or more patient-doctor contacts within 8 weeks of the index consultation. Within an episode, patient demographics and prescribing patterns were analysed including number of treatments, and the category and sequence of individual medicines.

RESULTS

A total of 1761 impetigo episodes were managed, with an incidence rate of 13.6 per 1000 person years. Impetigo peaked in summer. Most patients, the majority children, experienced a single episode (93%), and 25% had eczema as comorbidity. Topical antibiotics (primarily fusidic acid) were the most prescribed initial treatments (85%), followed by oral antibiotics (14%). Topical antibiotics were progressively used less over subsequent treatments, while there was an inverse increase in oral antibiotic use. Topical fusidic acid as the most common first line treatment seemed satisfactory as only 12% of initial treatments with this drug received further therapy. Repeat treatments generally occurred within 7 days.

CONCLUSION

This study of impetigo prescribing patterns in primary care highlighted that Dutch general practitioners were generally adherent to national treatment guidelines. Topical treatment, and if needed systemic small-spectrum antibiotic treatment, appeared satisfactory; these findings aid in antimicrobial stewardship.

Infectious skin disorders encountered in a pediatric emergency department of a tertiary care hospital in Argentina: a descriptive study

BACKGROUND

Infectious skin disorders (ISDs) are commonly seen in pediatric emergency departments (PED), however the exact frequency is unknown. We provide an accurate evaluation of the incidence and characteristics of ISDs diagnosed in a PED from Buenos Aires, Argentina, over a 1-year period.

METHODS

Prospectively, descriptive study of children evaluated in the PED with ISDs during 2016. ISDs were analyzed on the basis of their incidence, patient demographics, seasonal variations, and hospitalization rates.

RESULTS

ISDs were diagnosed in 1680 (67.9%) of the skin consultations (M/F: 1.1; mean age: 4.4 ± 3.7 years). Bacterial infections were observed in 932 (55.5%) cases. Viral infections were seen in 604 patients (35.9%). Fungal and parasite skin infections were diagnosed in 33 (2%) and 111 (6.6%) children, respectively. The most frequent ISDs according to the etiology group were impetigo 377 (22.4%), varicella 397 (23.6%), tinea capitis 10 (0.6%), and scabies 109 (6.5%). A higher frequency of ISDs were reported during the summer (38.4%) and spring (38.2%) months. Bacterial skin infections were more frequent during the summer months, while viral skin infections were more prevalent during spring. Parasitic skin infections were diagnosed more frequently during the winter months. No differences were seen for mycotic skin infections. Hospitalization rate was 1% (all for bacterial skin infections).

CONCLUSION

Our data reveal the extremely high frequency of ISDs seen at the PED, underlying the need for closer cooperation between dermatologists and pediatricians.

Hospital admissions for skin infections among Western Australian children and adolescents from 1996 to 2012

The objective of this study was to describe the occurrence of skin infection associated hospitalizations in children born in Western Australia (WA). We conducted a retrospective cohort study of all children born in WA between 1996 and 2012 (n = 469,589). Of these, 31,348 (6.7%) were Aboriginal and 240,237 (51.2%) were boys. We report the annual age-specific hospital admission rates by geographical location and diagnostic category. We applied log-linear regression modelling to analyse changes in temporal trends of hospitalizations. Hospitalization rates for skin infections in Aboriginal children (31.7/1000 child-years; 95% confidence interval [CI] 31.0–32.4) were 15.0 times higher (95% CI 14.5–15.5; P<0.001) than those of non-Aboriginal children (2.1/1000 child-years; 95% CI 2.0–2.1). Most admissions in Aboriginal children were due to abscess, cellulitis and scabies (84.3%), while impetigo and pyoderma were the predominant causes in non-Aboriginal children (97.7%). Admissions declined with age, with the highest rates for all skin infections observed in infants. Admissions increased with remoteness. Multiple admissions were more common in Aboriginal children. Excess admissions in Aboriginal children were observed during the wet season in the Kimberley and during summer in metropolitan areas. Our study findings show that skin infections are a significant cause of severe disease, requiring hospitalization in Western Australian children, with Aboriginal children at a particularly high risk. Improved community-level prevention of skin infections and the provision of effective primary care are crucial in reducing the burden of skin infection associated hospitalizations. The contribution of sociodemographic and environmental risk factors warrant further investigation.

Understanding flucloxacillin prescribing trends and treatment non-response in UK primary care: a Clinical Practice Research Datalink (CPRD) study

Objectives

The volume of prescribed antibiotics is associated with antimicrobial resistance and, unlike most other antibiotic classes, flucloxacillin prescribing has increased. We aimed to describe UK primary care flucloxacillin prescribing and factors associated with subsequent antibiotic prescribing as a proxy for non-response.

Patients and methods

Clinical Practice Research Datalink patients with acute prescriptions for oral flucloxacillin between January 2004 and December 2013, prescription details, associated Read codes and patient demographics were identified. Monthly prescribing rates were plotted and logistic regression identified factors associated with having a subsequent antibiotic prescription within 28 days.

Results

3 031 179 acute prescriptions for 1 667 431 patients were included. Average monthly prescription rates increased from 4.74 prescriptions per 1000 patient-months in 2004 to 5.74 (increase of 21.1%) in 2013. The highest prescribing rates and the largest increases in rates were seen in older adults (70+ years), but the overall increase in prescribing was not accounted for by an ageing population. Prescribing 500 mg tablets/capsules rather than 250 mg became more common. Children were frequently prescribed low doses and small volumes (5 day course) and prescribing declined for children, including for impetigo. Only 4.2% of new prescriptions involved co-prescription of another antibiotic. Age (<5 and ≥60 years), diagnosis of ‘cellulitis or abscess’ or no associated code, and 500 mg dose were associated with a subsequent antibiotic prescription, which occurred after 17.6% of first prescriptions.

Conclusions

There is a need to understand better the reasons for increased prescribing of flucloxacillin in primary care, optimal dosing (and the need to co-prescribe other antibiotics) and the reasons why one in five patients are prescribed a further antibiotic within 4 weeks.

Fabric-skin models to assess infection transfer for impetigo contagiosa in a kindergarten scenario

Children in community bodies like kindergartens are predisposed to suffer from impetigo. To consider important measures for infection prevention, direct and indirect transmission routes of pathogens must be revealed. Therefore, we studied the role of skin and fabrics in the spread of the impetigo pathogen Staphylococcus aureus and the strain Streptococcus equi (surrogate to Streptococcus pyogenes) in order to assess infection transfer in realistic scenarios. The transmission of test strains was studied with standardized fabric-skin models using a technical artificial skin and fabrics of different fiber types commonly occurring in German kindergartens. In synthetic pus, both test strains persisted on artificial skin and fabrics for at least 4 h. Friction enhanced transfer, depending on the fiber type or fabric construction. In a skin-to-skin setup, the total transfer was higher than via fabrics and no decrease in the transmission rates from donor to recipients could be observed after successive direct skin contacts. Children in kindergartens may be at risk of transmission for impetigo pathogens, especially via direct skin contact, but also by the joint use of fabrics, like towels or handicraft materials. Fabric-skin models used in this study enable further insight into the transmission factors for skin infections on the basis of a practical approach.

Climatic factors and community - associated methicillin-resistant Staphylococcus aureus skin and soft-tissue infections - a time-series analysis study

Skin and soft tissue infections caused by Staphylococcus aureus (SA-SSTIs) including methicillin-resistant Staphylococcus aureus (MRSA) have experienced a significant surge all over the world. Changing climatic factors are affecting the global burden of dermatological infections and there is a lack of information on the association between climatic factors and MRSA infections. Therefore, association of temperature and relative humidity (RH) with occurrence of SA-SSTIs (n = 387) and also MRSA (n = 251) was monitored for 18 months in the outpatient clinic at a tertiary care hospital located in Bhubaneswar, Odisha, India. The Kirby-Bauer disk diffusion method was used for antibiotic susceptibility testing. Time-series analysis was used to investigate the potential association of climatic factors (weekly averages of maximum temperature, minimum temperature and RH) with weekly incidence of SA-SSTIs and MRSA infections. The analysis showed that a combination of weekly average maximum temperature above 33 °C coinciding with weekly average RH ranging between 55% and 78%, is most favorable for the occurrence of SA-SSTIs and MRSA and within these parameters, each unit increase in occurrence of MRSA was associated with increase in weekly average maximum temperature of 1.7 °C (p = 0.044) and weekly average RH increase of 10% (p = 0.097).

Seasonality of infection rates after total joint arthroplasty

The correlation between season (fall, winter, spring, and summer) and infection rate in surgical patients is well defined in many specialties. To the authors' knowledge, there are no data in the literature on this phenomenon in patients undergoing total joint arthroplasty. They hypothesized that there would be an increased infection rate in the summer months in patients undergoing elective total joint arthroplasty. They retrospectively reviewed consecutive patients undergoing elective total hip or knee arthroplasty at a single institution during 1 year by a single surgeon. Wound infections were defined as any patient requiring oral antibiotics for cellulitis, readmission for intravenous antibiotics, a return to the operating room for irrigation and debridement, or excisional arthroplasty and placement of a cement spacer within 90 days of the initial procedure. Seventeen of 750 patients developed an infection, for an overall incidence of 2.2%. There was a statistically significant difference in infection rate according to season: 3 (1.5%) infections occurred in winter, 1 (0.5%) in spring, 9 (4.7%) in summer, and 4 (2.4%) in fall. The incidence was highest during July (4.5%), August (5.4%), and September (4.3%). There was a statistically significant difference in infection rate between summer/fall (3.6%) vs winter/spring (1.0%). There is an increase in the incidence of infection during summer months for patients undergoing total joint arthroplasty. The authors recommend increased surveillance and more thorough preoperative sterilization procedures during these warmer months.

The use of typing methods and infection prevention measures to control a bullous impetigo outbreak on a neonatal ward

BACKGROUND

We describe an outbreak of Bullous Impetigo (BI), caused by a (methicillin susceptible, fusidic acid resistant) Staphylococcus aureus (SA) strain, spa-type t408, at the neonatal and gynaecology ward of the Jeroen Bosch hospital in the Netherlands, from March-November 2011.

METHODS

We performed an outbreak investigation with revision of the hygienic protocols, MSSA colonization surveillance and environmental sampling for MSSA including detailed typing of SA isolates. Spa typing was performed to discriminate between the SA isolates. In addition, Raman-typing was performed on all t408 isolates.

RESULTS

Nineteen cases of BI were confirmed by SA positive cultures. A cluster of nine neonates and three health care workers (HCW) with SA t408 was detected. These strains were MecA-, PVL-, Exfoliative Toxin (ET)A-, ETB+, ETAD-, fusidic acid-resistant and methicillin susceptible. Eight out of nine neonates and two out of three HCW t408 strains yielded a similar Raman type. Positive t408 HCW were treated and infection control procedures were reinforced. These measures stopped the outbreak.

CONCLUSIONS

We conclude that treatment of patients and HCW carrying a predominant SA t408, and re-implementing and emphasising hygienic measures were effective to control the outbreak of SA t408 among neonates.

The seasonality of postoperative infection in spine surgery

OBJECT

Studies from many disciplines have found an association with the summer months, elevated temperature, humidity, and an increased rate of infection. The "July effect," a hypothesis that the inexperience of new house staff at the beginning of an academic year leads to an increase in wound complications, has also been considered. Finally, an increase in trauma-related admissions in the summer months is likely to result in an increased incidence of postoperative infections. Two previous studies revealed mixed results concerning perioperative spinal wound infections in the summer months. The purpose of this study was to determine the months and/or seasons of the year that display significant fluctuation of postoperative infection rate in spine surgery. Based on the idea that infection rates are susceptible to seasonal factors, the authors hypothesized that spinal infections would increase during the summer months.

METHODS

Inclusion criteria were all spine surgery cases at a single tertiary referral institution between January 2005 and December 2009; 8122 cases were included. Patients presenting with a contaminated wound or active infection were excluded. Infection rates were calculated on a monthly and seasonal basis and compared.

RESULTS

A statistically significant increase in the infection rate was present on both a seasonal and monthly basis (p = 0.03 and p = 0.024) when looking at the seasonal change from spring to summer. A significant decrease in the infection rate was seen on a seasonal basis during the change from fall to winter (p = 0.04). The seasonal rate of infection was highest in the summer (4.1%) and decreased to the lowest point in the spring (2.8%) (p = 0.03).

CONCLUSIONS

At the authors' institution, spine surgeries performed during the summer and fall months were associated with a significantly higher incidence of wound infection compared with the winter and spring. These data support the existence of a seasonal effect on perioperative spinal infection rates, which may be explained by seasonal variation in weather patterns and house staff experience, among other factors.

Differences in methicillin-resistant Staphylococcus aureus strains isolated from pediatric and adult patients from hospitals in a large county in California

Studies of U.S. epidemics of community- and health care-associated methicillin-resistant Staphylococcus aureus (MRSA) suggested differences in MRSA strains in adults and those in children. Comprehensive population-based studies exploring these differences are lacking. We conducted a prospective cohort study of inpatients in Orange County, CA, collecting clinical MRSA isolates from 30 of 31 Orange County hospitals, to characterize differences in MRSA strains isolated from children compared to those isolated from adults. All isolates were characterized by spa typing. We collected 1,124 MRSA isolates from adults and 159 from children. Annual Orange County population estimates of MRSA inpatient clinical cultures were 119/100,000 adults and 22/100,000 children. spa types t008, t242, and t002 accounted for 83% of all isolates. The distribution of these three spa types among adults was significantly different from that among children (χ(2) = 52.29; P < 0.001). Forty-one percent of adult isolates were of t008 (USA300), compared to 69% of pediatric isolates. In multivariate analyses, specimens from pediatric patients, wounds, non-intensive care unit (ICU) wards, and hospitals with a high proportion of Medicaid-insured patients were significantly associated with the detection of t008 strains. While community- and health care-associated MRSA reservoirs have begun to merge, significant differences remain in pediatric and adult patient populations. Community-associated MRSA spa type t008 is significantly more common in pediatric patients.

Seasonality of MRSA infections

Using MRSA isolates submitted to our hospital microbiology laboratory January 2001–March 2010 and the number of our emergency department (ED) visits, quarterly community-associated (CA) and hospital-associated (HA) MRSA infections were modeled using Poisson regressions. For pediatric patients, approximately 1.85x (95% CI 1.45x–2.36x, adj. p<0.0001) as many CA-MRSA infections per ED visit occurred in the second two quarters as occurred in the first two quarters. For adult patients, 1.14x (95% CI 1.01x–1.29x, adj.p = 0.03) as many infections per ED visit occurred in the second two quarters as in the first two quarters. Approximately 2.94x (95% CI 1.39x–6.21x, adj.p = 0.015) as many HA-MRSA infections per hospital admission occurred in the second two quarters as occurred in the first two quarters for pediatric patients. No seasonal variation was observed among adult HA-MRSA infections per hospital admission. We demonstrated seasonality of MRSA infections and provide a summary table of similar observations in other studies.

Increasing hospitalizations for serious skin infections in New Zealand children, 1990-2007

The incidence of serious skin infections in New Zealand children is significantly higher than in comparative countries. This study aimed to describe the epidemiology of these infections and identify changes in disease distribution over time. Discharge data were analysed for all children admitted to a New Zealand public hospital with a serious skin infection during the period 1990-2007. Patient and admission variables were compared between 1990-1999 and 2000-2007. The incidence of serious skin infections almost doubled from 298·0/100,000 in 1990 to 547·3/100,000 in 2007. The highest rates were observed in boys, preschool-aged children, Māori and Pacific children, those living in deprived neighbourhoods, urban areas and northern regions. Over time there were disproportionate increases in infection rates in Māori and Pacific children and children from highly deprived areas. Serious skin infections are an increasing problem for New Zealand children. Worsening ethnic and socioeconomic health inequalities may be contributing to increasing rates.

Proposed epidemiological case definition for serious skin infection in children

AIM

Researching the rising incidence of serious skin infections in children is limited by the lack of a consistent and valid case definition. We aimed to develop and evaluate a good quality case definition, for use in future research and surveillance of these infections.

METHODS

We tested the validity of the existing case definition, and then of 11 proposed alternative definitions, by assessing their screening performance when applied to a population of paediatric skin infection cases identified by a chart review of 4 years of admissions to a New Zealand hospital.

RESULTS

Previous studies have largely used definitions based on the International Classification of Diseases skin infection subchapter. This definition is highly specific (100%) but poorly sensitive (61%); it fails to capture skin infections of atypical anatomical sites, those secondary to primary skin disease and trauma, and those recorded as additional diagnoses. Including these groups produced a new case definition with 98.9% sensitivity and 98.8% specificity.

CONCLUSION

Previous analyses of serious skin infection in children have underestimated the true burden of disease. Using this proposed broader case definition should allow future researchers to produce more valid and comparable estimates of the true burden of these important and increasing infections.

[Primary cutaneous infections due to Staphylococcus and Streptococcus]

Pyodermitis constitutes a very important chapter in dermatological practice. Its pathogenesis, in special the one caused by S. aureus, has improved due to the knowledge of the role developed by the host defensins, quorum-sensing signaling and the Panton-Valentine leucocidin gene among others. As well, exfoliative toxins and enterotoxins responsible for the staphylococal scalded skin syndrome (SSSS) and toxic shock syndrome, respectively, have been cloned. Also, it has been seen that bullous impetigo, SSSS and pemphigus foliaceus share a common target: desmoglein-1. The Panton-Valentine leucocidin gene has been related to the appearance of abscesses, necrotic cutaneous lesions and furuncles in young persons caused by meticillin resistant S. aureus, with its epidemiological implications. Finally, some atypical forms of erysipelas suppose a diagnostic challenge for the dermatologist.

Incidence of lower-extremity cellulitis: a population-based study in Olmsted county, Minnesota

OBJECTIVE

To determine the population-based incidence of lower-extremity cellulitis.

METHODS

We performed a population-based survey with the resources of the Rochester Epidemiology Project in Olmsted County, Minnesota. We identified residents of Olmsted County who sought care for cellulitis from January 1, 1999, through December 31, 1999, reviewed medical records to ascertain agreement with a case definition of lower-extremity cellulitis, and calculated the population-based incidence of lower-extremity cellulitis.

RESULTS

During 1999, 176 episodes met the case definition of lower-extremity cellulitis; the incidence of lower-extremity cellulitis in Olmsted County was 199 per 100,000 person-years. Sex-specific incidence was 197 per 100,000 person-years for women and 201 per 100,000 person-years for men. In a sex-adjusted model, the incidence increased 3.7% (95% confidence interval, 2.9%-4.5%) per year increment in age or 43.8% (95% confidence interval, 33.6%-54.7%) per 10-year increment. The incidence of cellulitis significantly increased with age (P<.001 in Poisson regression) but was not statistically significantly different between the sexes.

CONCLUSIONS

The incidence of lower-extremity cellulitis in this population-based study was high and was affected by age. In contrast, sex did not influence infection incidence. The need for hospitalization and the prevalence of recurrence of lower-extremity cellulitis added to the burden of disease in Olmsted County.

Impetigo in epidemic and nonepidemic phases: an incidence study over 4½ years in a general population

BACKGROUND

Little is known about incidence and natural variation of impetigo in general populations.

OBJECTIVES

To investigate the natural course of impetigo in a well-defined population, and to study the resistance pattern of the causal bacteria over time.

METHODS

This is a population-based incidence study in Austevoll, an island community of 4457 inhabitants in Norway, in the years 2001-2005. Incidence rates are given as events per person-year. Epidemic periods were identified by statistical process-control analyses.

RESULTS

The incidence rate of impetigo for the whole study period was 0.017 events per person-year, corresponding to a total of 334 cases. The incidence rates were 0.009, 0.026, 0.019, 0.016 and 0.009 in the years 2001, 2002, 2003, 2004 and 2005, respectively. Three epidemics were identified, starting in August of 2002, 2003 and 2004, lasting for 11, 11 and 5 weeks, respectively. Incidence rates in these epidemic periods were 0.099, 0.045 and 0.074, respectively. In epidemic periods, Staphylococcus aureus was the causal bacterium in 89% (117/132) of cases, while this proportion was 68% (84/123) in nonepidemic periods (P < 0.01). Staphylococcus aureus was resistant to fusidic acid in 84% (98/117) and 64% (54/84) of impetigo cases in epidemic and nonepidemic periods, respectively (P < 0.01). When investigating all types of infections caused by S. aureus in the study period, the proportion of fusidic acid resistance in impetigo cases (152/201, 76%) differed significantly from fusidic acid resistance in other infections (18/116, 16%) (P < 0.01).

CONCLUSIONS

Distinctive epidemic outbreaks occurred during the summer of three of the five follow-up years. In outbreaks, S. aureus was more frequently the causal agent and the sensitivity to fusidic acid decreased significantly.

European Surveillance of Antimicrobial Consumption (ESAC): outpatient penicillin use in Europe

BACKGROUND

Data on outpatient penicillin use in Europe were collected from 25 countries within the ESAC project, funded by DG SANCO of the European Commission, using the WHO ATC/DDD methodology.

METHODS

For the period 1997-2003, data on outpatient use of systemic penicillins aggregated at the level of the active substance were collected and expressed in DDD (WHO, version 2004) per 1000 inhabitants per day (DID). Of the 'Penicillins' (J01C), outpatient use of narrow-spectrum penicillins (J01CE), broad-spectrum penicillins (J01CA), penicillinase-resistant penicillins (J01CF) and combinations with beta-lactamase inhibitors (J01CR) in 25 European countries was analysed in detail.

RESULTS

Total outpatient penicillin use in 2003 varied by a factor of 4 between the country with the highest (15.27 DID in Slovakia) and lowest use (3.86 DID in the Netherlands). Narrow-spectrum penicillins, broad-spectrum penicillins and combinations with beta-lactamase inhibitors were used most in 4, 12 and 9 countries, respectively. Penicillin use increased by more than 1 DID in nine countries, whereas it decreased by more than 1 DID in two countries (Czech Republic, France). An increase of the use of combinations with beta-lactamase inhibitors by more than 10% in 10 countries coincided with an equal decrease of broad-spectrum penicillins in seven countries and narrow-spectrum penicillins in three countries.

CONCLUSION

Penicillins represent the most widely used antibiotic class in all 25 participating countries; albeit with considerable variation of their use patterns. A distinct shift from narrow-spectrum penicillins to broad-spectrum penicillins, and specifically their combinations with beta-lactamase inhibitors, was observed during the period 1997-2003.