Surveillance of nosocomial fungal infections in a burn care unit

Nosocomial outbreak of Candida parapsilosis sensu stricto fungaemia in a neonatal intensive care unit in China

BACKGROUND

Candida parapsilosis is a common agent of fungaemia, but few outbreaks of Candida parapsilosis infection have been reported in China.

AIM

To elaborate an outbreak of nosocomial Candida parapsilosis sensu stricto fungaemia in a neonatal intensive care unit (NICU) of a comprehensive hospital in China from July to October 2017.

METHODS

Epidemics and characteristics of fungaemia cases were investigated. Surveillance samples were collected. Vitek 2 Compact System, internal transcribed spacer sequencing, and random amplified polymorphic DNA (RAPD) typing were conducted to identify the isolates. Antifungal susceptibility test was performed for all bloodstream isolates.

FINDINGS

Sixteen neonates were diagnosed as Candida parapsilosis sensu stricto fungaemia during this period. Presenting symptoms included leucopenia, thrombocytopenia, and respiratory crackles. Fifteen cases were cured whereas one case who suffered from severe concomitant diseases died. The isolates were susceptible to fluconazole, amphotericin B, itraconazole, voriconazole, and 5-fluorocytosine. A total of 313 surveillance samples were collected, and Candida parapsilosis sensu stricto was identified from 16 environmental samples and one sample from an ultrasonographer's hand. The colonized locations included wiping cloths, faucets, sinks, operating table, puddles in the bathroom, a ventilator, and an ultrasonic probe. The RAPD patterns of all the Candida parapsilosis sensu stricto isolates from bloodstream and surveillance samples were identical. The outbreak was controlled after a series of infection control measures.

CONCLUSION

Contaminated environment was associated with this outbreak. Close attention to immunocompromised patients, thorough environmental disinfection and hand hygiene should be strengthened in NICU.

Synthesized zinc peroxide nanoparticles (ZnO2-NPs): a novel antimicrobial, anti-elastase, anti-keratinase, and anti-inflammatory approach toward polymicrobial burn wounds

Increasing of multidrug resistance (MDR) remains an intractable challenge for burn patients. Innovative nanomaterials are also in high demand for the development of new antimicrobial biomaterials that inevitably have opened new therapeutic horizons in medical approaches and lead to many efforts for synthesizing new metal oxide nanoparticles (NPs) for better control of the MDR associated with the polymicrobial burn wounds. Recently, it seems that metal oxides can truly be considered as highly efficient inorganic agents with antimicrobial properties. In this study, zinc peroxide NPs (ZnO₂-NPs) were synthesized using the co-precipitation method. Synthesized ZnO₂-NPs were characterized by X-ray diffraction, Fourier transformed infrared, transmission electron microscopy, thermogravimetric analysis, differential scanning calorimetry, and ultraviolet-visible spectroscopy. The characterization techniques revealed synthesis of the pure phase of non-agglomerated ZnO₂-NPs having sizes in the range of 15–25 nm with a transition temperature of 211°C. Antimicrobial activity of ZnO₂-NPs was determined against MDR Pseudomonas aeruginosa (PA) and Aspergillus niger (AN) strains isolated from burn wound infections. Both strains, PA6 and AN4, were found to be more susceptible strains to ZnO₂-NPs. In addition, a significant decrease in elastase and keratinase activities was recorded with increased concentrations of ZnO₂-NPs until 200 µg/mL. ZnO₂-NPs revealed a significant anti-inflammatory activity against PA6 and AN4 strains as demonstrated by membrane stabilization, albumin denaturation, and proteinase inhibition. Moreover, the results of in vivo histopathology assessment confirmed the potential role of ZnO₂-NPs in the improvement of skin wound healing in the experimental animal models. Clearly, the synthesized ZnO₂-NPs have demonstrated a competitive capability as antimicrobial, anti-elastase, anti-keratinase, and anti-inflammatory candidates, suggesting that the ZnO₂-NPs are promising metal oxides that are potentially valued for biomedical applications.

Fungal infections in burns: Diagnosis and management

Burn wound infection (BWI) is a major public health problem and the most devastating form of trauma worldwide. Fungi cause BWI as part of monomicrobial or polymicrobial infection, fungaemia, rare aggressive soft tissue infection and as opportunistic infections. The risk factors for acquiring fungal infection in burns include age of burns, total burn size, body surface area (BSA) (30-60%), full thickness burns, inhalational injury, prolonged hospital stay, late surgical excision, open dressing, artificial dermis, central venous catheters, antibiotics, steroid treatment, long-term artificial ventilation, fungal wound colonisation (FWC), hyperglycaemic episodes and other immunosuppressive disorders. Most of the fungal infections are missed owing to lack of clinical awareness and similar presentation as bacterial infection coupled with paucity of mycology laboratories. Expedient diagnosis and treatment of these mycoses can be life-saving as the mortality is otherwise very high. Emergence of resistance in non-albicans Candida spp., unusual yeasts and moulds in fungal BWI, leaves very few fungi susceptible to antifungal drugs, leaving many patients susceptible. There is a need to speciate fungi as far as the topical and systemic antifungal is concerned. Deep tissue biopsy and other relevant samples are processed by standard mycological procedures using direct microscopy, culture and histopathological examination. Patients with FWC should be treated by aggressive surgical debridement and, in the case of fungal wound infection (FWI), in addition to surgical debridement, an intravenous antifungal drug, most commonly amphotericin B or caspofungin, is prescribed followed by de-escalating with voriconazole or itraconazole, or fluconazole depending upon the species or antifungal susceptibility, if available. The propensity for fungal infection increases, the longer the wound is present. Therefore, the development of products to close the wound more rapidly, improvement in topical antifungal therapy with mould activity and implementation of appropriate systemic antifungal therapy guided by antifungal susceptibility may improve the outcome for severely injured burn victims.

Epidemiological and clinico-mycological profile of fungal wound infection from largest burn centre in Asia

The current study was conducted to know the incidence, predisposing factors, spectrum, clinical profile and antifungal susceptibility (AFS) of fungal wound infection (FWI) in burn patients. Of a total of 71 patients, 20 (28.2%) emerged with the diagnosis of FWI. Fungal pathogens in this study were Candida tropicalis (14%), Candida parapsilosis (5.6%), Aspergillus niger (2.8%) and one each of Candida albicans (1.4%), Candida glabrata (1.4%), Syncephalestrum (1.4%) and Fusarium solani (1.4%). All patients with mould infections expired before the mycological culture results could be conveyed to clinicians. Of the yeasts isolated in the study, one each of C. tropicalis and C. albicans showed cross-resistance to azoles. All the moulds were susceptible to amphotericin B. This study depicted that fungal invasion is associated with a high mortality, burn size 30-60% and high incidence of inhalational injury. Fungal invasion was detected on an average of 14 days after injury. Association of use of four classes of drugs - aminoglycosides, imipenem, vancomycin and third generation cephalosporins and use of total parenteral nutrition was observed. Expedient laboratory diagnosis of FWI and appropriate systemic antifungal therapy guided by AFS may improve outcome for severely injured burn victims.

Fungal colonisation in burn wounds: An Indian scenerio

Burn patients are susceptible hosts for fungal colonisation.

AIM

To study incidence and profile of fungal colonisation of burn wounds.

MATERIALS AND METHODS

This prospective study was conducted in 201 consecutive adult patients (39 male and 162 female) with burn wounds, admitted from October 2005 to September 2006. Wounds with clinical suspicion of fungal colonisation were biopsied and examined by wet smear, Potassium hydroxide (KOH) mount, nigrosin stain, 1% Acid fast bacilli (AFB) stain, Gomori methenamine silver (GMS) stain, histopathological examination and fungal culture. All wounds with suspicion of fungal colonisation were treated with topical application of miconazole ointment mixed with povidone-iodine/silver sulphadiazine topically and itraconazole (oral) systemically.

RESULTS

Fungal infection of burn wound was suspected in 77 patients (38.31%) with 20-70% total body surface area (TBSA) burns. Ninety-two biopsy samples were collected from 77 patients. On investigations, fungal colonisation was confirmed in 35 patients. Culture was positive in 23 patients with Candida in 12 and Aspergillus in 4. GMS stain and KOH stain showed sensitivity and specificity of 70.8% and 86.5%, respectively for detecting fungi in burn wound. Nigrosin stain was negative in all patients. Duration of hospitalisation was more in patients having fungal colonisation without any significant effect on the mortality

DISCUSSION

In 38.31% of patients fungal colonisation was clinically suspected and it was confirmed in 17.41% of 201 patients. GMS stain and KOH stain were observed to have acceptable sensitivity and specificity. With increasing prevalence of Aspergillus, flucanazole cannot be relied upon in controlling fungal colonisation and drugs like itraconazole may have to be used as empirical therapy.

CONCLUSION

Fungal colonisation of burn wound is not uncommon and should be suspected. Fungi detected most commonly were Candida and Aspergillus. KOH and GMS stain were identified as reliable, simple and inexpensive methods for confirming fungal colonisation.

A prospective study of hospital-acquired infections in burn patients at a tertiary care referral centre in North India

A prospective study was carried out in a burn unit of a tertiary care referral centre in North India. Patients with 20-70% TBSAB were enrolled. Seventy-one patients developed 59 hospital-acquired infections (HAI); the infection density being 36.2 infections per 1000 patient days. Invasive wound infections were the commonest (33), followed by blood stream infections (22), urinary tract infections (3) and pneumonia (1). Infection contributed to 75% of observed mortality. On logistic regression analysis, infected patients were more likely to die as well as stay longer in the hospital as compared to non-infected patients. Infected patients also had more central venous lines inserted. The mortality was related to percent TBSAB. Thirteen out of 18 patients who had TBSAB more than 60% died as compared to 5 out of 31 with TBSAB less than 40%. Staphylococcus aureus, Pseudomonas aeruginosa and beta-hemolytic streptococci (BHS) were the most frequent organisms causing hospital-acquired infection. Except for BHS all other organisms were highly drug resistant. Better compliance with hand washing and barrier nursing techniques, stricter control over disinfection and sterilization practices and usage of broad spectrum antibiotics, and reduction of the environmental contamination with S. aureus are required to reduce the HAI rates.

Epidemiology and molecular typing of Candida isolates from burn patients

This study, spread over a span of 2 years describes Candida infections in burn patients of an Indian hospital. A total of 220 burn patients were monitored and Candida could be isolated from 138 patients. A total of 228 different Candida species were obtained from various body locations of these patients. Species identification revealed that Candida albicans was the most predominant (45%) followed by Candida tropicalis (33%), Candida glabrata (13.5%), C. parapsilosis (4%), C. krusei (2.75%) and C. kefyr (1.75%). DNA fingerprinting of all C. albicans isolates was done by using CARE-2 probe. Fingerprinting analyses of all the C. albicans strains revealed that strains collected from different patients were different. It is noteworthy that patients with disseminated candidiasis had a similar, but unique strain isolated from all body locations, suggesting a possibility that commensal isolates might be turning pathogenic. Taken together, this is probably the first ever detailed survey of Candida infections in burn patients in India and is expected to lead to better clinical management of this group of patients.

High rate of candidemia in patients sustaining injuries in a bomb blast at a marketplace: a possible environmental source

In this study, a cluster of candidemia among patients sustaining injuries in a bomb blast at a marketplace was investigated by means of a multivariate analysis, a case-control study, and quantitative air sampling. Candidemia occurred in 7 (30%) of 21 patients (58% of those admitted to the intensive care unit [ICU]) between 4 and 16 days (mean, 12 days) after the injury and was the single most frequent cause of bloodstream infections. Inhalation injury was the strongest predictor for candidemia by multivariate analysis. Candidemia among the case patients occurred at a significantly higher rate than among comparable trauma patients injured in different urban settings, including a pedestrian mall (2 of 29; P=. 02), and among contemporary ICU control patients (1 of 40; P=.001). Air sampling revealed exclusive detection of Candida species and increased mold concentration in the market in comparison with the mall environment. These findings suggest a role for an exogenous, environmental source in the development of candidemia in some trauma patients.

Correlation between fungi isolated from burn wounds and burn care units

A comparison was made prospectively between fungal isolates from patients and burn care units. Aspergillus niger was the most frequent isolate in both patients and burn care units whereas Ulocladium was the commonest isolate in the control group. Aspergillus terreus, Penicillium and Zygomycetes, which were recovered from burned patients, were also found more frequently in the burn care units than in the control group (other areas in the hospital). These findings indicate a potential risk of fungal infection which can be acquired from the immediate surroundings of patients in burn care units. Periodical burn ward decontamination is therefore recommended.

Primary cutaneous aspergillosis: our experience in 10 years

We describe nine patients with primary cutaneous aspergillosis who were diagnosed during the 10-year period between 1987 and 1996. All except one were adults. Seven of those nine cases had an immunocompromised state. Among the immunocompromised patients, six had burn wounds and one was a renal transplant recipient. Aspergillus flavus was isolated from seven patients and A. fumigatus from one, and in one other case the species could not be determined. Three patients who had total burn surface area of more than 70% died. The other patients responded well to extensive surgical debridement with or without institution of oral itraconazole.

Aerobic, anaerobic and fungal burn wound infections

One hundred and twenty-seven patients were studied prospectively for aerobic, anaerobic and fungal burn wound infections. All cases yielded organisms on culture. A total of 377 isolates were recovered (239 aerobes, 116 anaerobes and 22 fungi). Aerobic bacteria alone were present in 49 patients (38.6%). Anaerobic bacteria alone were present in four patients (3.2%). Candida sp. alone was present in one patient (0.8%). Mixed aerobic and/or anaerobic bacteria and/or fungi were present in 73 patients (57.5%). Fungi were isolated from 21 patients (23.9%) of 88 patients having fungal cultures. The predominant isolates recovered in descending order of frequency were: Pseudomonas aeruginosa, Staphylococcus aureus, Bacteroides sp., Klebsiella sp. and Peptostreptococcus sp. There were 70 patients (55.1%) infected with anaerobic bacteria. The rate of recovery of anaerobes was higher in patients with open wound dressing (72.7%) than in patients with occlusive wound dressings (41.7%), (P < 0.01). Seventeen patients presented with septic shock, 15 of them (88.2%) yielding positive anaerobic cultures. Bacteroides sp. were isolated from 14 patients with septic shock, and were recovered from the four patients who had anaerobic infection alone. These results indicate a significant role of Bacteroides sp. in burn wound sepsis.

Nosocomial infections in a burn intensive care unit

Although many studies have reviewed burn wound infections (BWIs) in burn patients, few have prospectively surveyed other nosocomial infections. Seriously burned patients are clearly at increased risk for infection due to the nature of the burn injury itself, immunocompromising effects of burn injury, prolonged hospital stays, and invasive diagnostic and therapeutic procedures. Over 6 months, we prospectively reviewed all patients admitted to our burn intensive care unit (BICU) for nosocomial infections. We used standard CDC definitions of nosocomial infections (NIs). Because we had previously documented a high incidence of nosocomial pneumonias in these patients, we were particularly interested in determining risk factors for nosocomial pneumonia. The total census during the study period was 57. There were 40 discharges and deaths. Surveillance demonstrated 36 nosocomial infections in 26 patients, for a total of 90 nosocomial infections per 100 discharges and deaths, or 32.3 NIs/1000 patient days. Infections included 22 pneumonias, 10 urinary tract infections, two bacteraemias, one BWI and one episode of cellulitis. Intubation was strongly associated with nosocomial infection, particularly with pneumonia, BWI and bacteraemia. Sixty per cent of all patients were intubated at some time during their BICU stay, but 88 per cent of those who developed a nosocomial infection were intubated (P < 0.001). Inhalation injury was less significant than intubation in the development of nosocomial infection. All patients who developed pneumonia or a BWI were intubated.(ABSTRACT TRUNCATED AT 250 WORDS)