Frequency, Clinical Presentation and Microbiological Spectrum of Candidemiain a Tertiary Care Center in Karachi, Pakistan.
Objective: To document the frequency, clinical presentation, outcome and spectrum of species in Candida blood stream infection.
Methods: A prospective, descriptive cohort study was conducted from June 1st till November 30th 2012 at the Sindh Institute of Urology and Transplantation in Karachi, Pakistan. All patients Greater than 15 years of age from nephrology, urology, gastroenterology, oncology or intensive care units with candidemia were included.
Results: Of 2457 positive blood cultures, 145 (6%) were positive for Candida species in 121 patients. Seventy seven patients were included for further analysis as clinical data was available for these..
Table-1: Demographics, clinical characteristics and outcome in 77 hospitalized patients with candidemia.
Demographic and Clinical###Candidemia
Characteristics###(n= 77) (%)
Age###35.87 +- 13.27
ICU Stay Greater than 7 days 12(15.6)
Associated Co-morbiditiesd###6 (7.8)
Immunosuppressant medicationse5 (6.5)
Prior Antibiotic Exposuref###52(67.5)
Site of Central Line
u Intra-Jugular###20 (26)
Source of candidemia
u Central line
Greater than 48 hours###65(84.4)
u Urinary tract###3 (3.9)
u Post Surgical###9(11.6)
u Died###18 (23.4)
a. Hospitalization within 4 weeks prior to current admission. b. Does not include antifungal antimicrobials. c. Endocarditis, pulmonary emboli, stroke. d. Diabetes, neutropenia or malignancy.
e. Steroids or antineoplastic medications. f. Antibiotic exposure within prior 4 weeks. g. Total parenteral nutrition.
Table-2: Microbiological spectrumin 77 hospitalized patients with candidemia.
Species of Candida###Frequency###Percentage
The majority of patients had renal failure (89.6%) and 44% had femoral line. Non- albicans species were isolated in 70 (90.9%) patients; Candida parapsilosis in 28 (36.4%), C. lusitaniae in 23 (29.9%), C. tropicalis in 16 (20.8%), C. glabrata in 3 (3.9%) with only 7 (9.1%) with C. albicans. Mortality was 23.4% (18 patients).
Conclusion: Frequency of candidemia and species distribution with predominantly non-albicans candida in our study is similar to that reported from other developing countries. Mortality is high. The majority of our patients had line related candidemia. Therefore prevention of line infection must be our top priority.
Keywords: Candida, Candidemia, Central line associated blood stream infection, Non Albicans candida, C. Albicans, Blood stream infection. (JPMA 64: 281; 2014).
Candidaspecies are the most common cause of fungal infections worldwide. The incidence of Candida infection has risen greatly since the 1940s, when widespread use of antibiotics was introduced. Candida infections can range from localized mucocutaneous involvement to disseminated candidiasis involving virtually any organ.
Candida species are the fourth most common cause of bloodstream infections (BSI) in the United States, often associated with a high mortality.1 A study in Switzerland found Candida species to be the seventh most common cause of BSI in hospitals.2 The burden of this illness in terms of morbidity, mortality and expense is enormous.3,4 Attributable mortality has been reported in the range of 5%-71%.4
Developing countries are increasingly reporting trends in Candida infection that are similar to those of countries with advanced medical care.Brazil has reported an overall incidence of 2.49 cases of candidemia per 1000 admissions.Verma et al. from India ranked Candida species as eighth among all isolates from BSI.5
The most important predisposing factors for candida infection are the use of antibiotics and indwelling intravenous catheters.6,7 Neutropenia, surgical procedures and total parenteral nutrition are also significant risk factors for invasive candida infection.6
There are more than 150 species of Candida but only 9 are regarded as pathogenic for humans: C. albicans, C. guillermondii, C. krusei, C. parapsilosis, C, tropicalis, C. psuedotropicalis, C, lusitaniae, C. dubliniensis and C. glabrata.Recently, there has been an increase in the frequency of non-albicans species as etiological agents of candidemia.3
Increasing antifungal resistance in Candida species is emerging. Candidaglabrata is often resistant to fluconazole, C. krusei is intrinsically resistant to azoles,8 while C. lusitaniae can be resistant to amphotericin B deoxycholate.9 As yet, antifungal susceptibility testing of candida is not widely available in Pakistan.
Data from Pakistan on candidemia is limited and there are no prospective studies. Studies have reported the leading causative agents to be C. albicansin neonatal candidemiaand C. tropicalisin invasive candidiasis in two separate studies from Karachi.10,11 Our study aims to document the frequency of Candidaamongst blood stream infections, its clinical presentation and outcome at a tertiary care center in Karachi. We also wanted to determine which species of Candida are most commonly isolated in blood stream infections at our institution.
Patients and Methods
This prospective study was conducted at the Sindh Institute of Urology and Transplantation (SIUT) in Karachi, Pakistan from June 1st till November 30th 2012. SIUT is a 500-bed urban tertiary care hospital.
All inpatients above the age of 15 years who were admitted in nephrology, urology, gastroenterology, oncology and intensive care units and had Candida species isolated in blood cultures, whether in monomicrobial or polymicrobial growth, either on admission or during the course of their hospitalization were included.
Patients on outpatient haemodialysis and renal transplant recipients with candidemia were excluded from the study. We did not include patients who fulfilled the eligibility criteria but had died or were transferred or discharged by the primary team prior to blood culture positivity for Candida species.
Patients were included only once with only their first episode of candidemia recorded. Demographic, clinical and microbiological data was documented in a proforma which included age, sex, diagnosis, co-morbidities, duration of hospitalization and antibiotic exposure prior to candidemia, ICU stay, presence of indwelling venous catheters, recent surgeries, steroids and parenteral nutrition. The most likely source of candidemia was evaluated and documented.The primary team was informed and referred to standard guidelines for the management of candidemia.12 We sought to follow the patient for the duration of the hospitalization for a maximum of 2 weeks from our initial visit and in-hospital mortality within this 2 week period was recorded.
Blood samples were inoculated in BACTEC 9240 system (Beckton, Dickinson, INC, Sparks, MD) and subsequently on blood agar. All Candida isolates, characterized by smooth, creamy white appearance of colonies on blood agar, underwent species identification using standard tests such as production of a germ tube test, morphology on cornmeal/Tween 80 agar, urease production, and the identification profile generated using API 20C Aux (bioMerieux). Antimicrobial sensitivity testing is not available at SIUT.
Candidemia was defined as the isolation of Candida species from at least 1 blood culture in the presence of signs and symptoms of systemic fungal infection.
Software SPSS, version 19, was used for statistical analysis. Continuous variables were dealt with mean and standard deviation. Categorical variables were analyzed as frequencies and percentages.
Approval for conducting the study was obtained from the Ethical Review Board of SIUT.
Over the 6 month study period, 8210 blood cultures were sent from inpatients that met the eligibility criteria. Of these, 2457(29.9%) blood cultures had microbial growth of which 145(6%) were positive for Candida species in 121 patients.
Of 121 patients, clinical data was available for 77 patients who were included for final analysis.. Of these, 57 (74%) had Candida species in monomicrobial, and 20 (26%) in polymicrobial cultures.
The mean age of participants was 35.87+-13.27 years. Females were 40 (51.95%). The majority of patients had renal failure 69 (89.6%) whereas 52 (67.5%) patients received antibiotics in prior 1 month before Candidemia. Thirty-four (44.2%) patients had femoral line in situ. Overall mortality was 18 (23.4%) patients. The details of the clinical and demographic features of patients with Candidemia are shown in Table-1.
None of the patients had received empirical antifungal therapy.
Predominantly, non- albicans species were isolated (91%). The most prevalent species was Candida parapsilosis (36.4%) followed by C. lusitaniae (29.9%). Only 7 (9.1%) patients had bloodstream infection with C. albicans (Table-2).
Our study has demonstrated a frequency of 6% Candida as a cause of bloodstream infection. This is similar to the prevalence of 6.14% for Candida species reported among blood culture isolates in Thailand.7 A study from India found a comparable prevalence rate of 6% for Candida species in blood stream infections.7
Most patients in our study had a central line. Candida species adhere to materials used in intravascular catheters which provide a nidus for infection.7 Our study found subclavian lines to be the least commonly infected, which is considered to be the preferred site for non-tunneled catheters in terms of risk for infection.13
Two-thirds of our patients had prior exposure to antibiotics, known to be an independent risk factor for candidemia.14 One-tenth of our patients were receiving total parenteral nutrition (TPN), identified in many multivariate studies to be an independent risk factor for invasive candidiasis and candidemia.14 Diabetic patients, of which we had 6, have been observed to have a greater degree of colonization with Candida species compared to control subjects.15
The majority of invasive infections due to Candida species have been attributed to five species; Candida albicans, Candida glabrata, Candida parapsilosis, Candida tropicalis and Candida krusei. However, the epidemiology of candidemia is different in various parts of the world and follows specific patterns.7
Hospital studies have found C. albicans to be the dominant species in candidemic patients in Europe and the USA, with prevalence ranging between 61.3% to 81.7% in European studies.17 C. Albicans is less common is Asia and we report a prevalence of 9.1% which is even lower than the 17-33% reported from India.17 It is the non-albicans species that predominate in Asia, Southern Europe and South America, as supported by our study (91%).
C. parapsilosis accounted for the highest proportion of Candida species in our study. In hospital based studies of candidemia, the frequency of C. parapsilosis was highest in Saudi Arabia (44%), Italy (35.5%), and Portugal (32%) whereas in India it varies from 9.5% to 20%.17 It is especially known for causing BSI in infants and neonates. C. parapsilosis is found commonly on the skin surface and has been associated with formation of biofilms in central catheters and other implanted devices, and the use of TPN solutions. C. parapsilosishas therefore been increasingly implicated in BSI after placement of intravascular devices.6 A study of invasive candidiasis from Pakistan also found that isolation of C. parapsilosis was higher with established central line associated blood stream infection (CLABSI)11 Since most of our patients had central lines, it is not surprising that we found C. parapsilosis to be the dominant species.
We report the highest prevalence worldwide of 29.9% of C. lusitaniae in patients with candidemia, and was the second most prevalent species in our study. In Europe, reported prevalence of C. lusitanieae in bloodstream infections was found to be highest in Greece, where its relative frequency was 5% in the neonatal ICU.USA reported a prevalence of 2.2%, Turkey 3.9%, whereas India has reported 4.8%.17 Another study from Australia in 2009 reported the prevalence of C. lusitanieae to be as high as 12%.18 High prevalence of C. lusitaniae in our institution may be attributable to its propensity to form abiofilm19 which makes it a likely pathogen in CLABSI. Further studies are required.
Epidemiological studies have implicated C. tropicalis in as many as 33-60% of cases of candidemia, mainly in patients with haematological malignancies and neutropenia.20 C. tropicalis was the third most prevalent species in our study (20.8%) whereas in India it is now the most common cause of nosocomial candidemia. C. tropicalis was also the most prevalent Candida species in a study of invasive candidiasis from Karachi, particularly in patients with chronic liver disease. Increased C. tropicalis gastrointestinal carriage, has been proposed as a factor predisposing to candidemia with this species.
C. glabrata was the least prevalent species in our study whereas it was found to be the most prevalent in studies from Europe where proportions of 19.6-27% have been reported. Prevalence of C. glabrata in candidemic patients in studies from India ranges from 9.5-17%, 3% from Saudia Arabia and 5% from the United Arab Emirates.17 C. glabratafungemia occurs more often in older adults and among patients with haematological malignancies.
Almost all our patients with candidemia, except 3 cases of C. glabrata, had isolation of species which are known to be sensitive to fluconazole. C. krusei was not isolated in any patient. In a study from Karachi, no resistance to fluconazole was found for C. parapsilosis, C. Lusitaniae,C. tropicalis and C. albicans, whereas 15% of C. glabrata were resistant.11 Therefore, fluconazole is an appropriate antifungal for empirical and directed therapy in the majority of candidemic patients. However, since C. glabrata can be resistant to fluconazole, whereas C. lusitaniaecan be resistant to amphotericin B deoxycholate, species identification is very important.
The species of Candida isolated has been seen in several studies to be an important determinant of the patient outcome. C. parapsilosis, which was the most common isolate in our study, was proved in other studies to have the lowest mortality rate.4 Our mortality rate of 23.4% is high but comparable or lower than those reported from other countries such as 27%in Australia,21 36.7% in Taiwan22 and 47% in Saudi Arabia.23 Delay in administering systemic antifungal therapy for the treatment of Candida bloodstream infection Greater than 12 hours after the first positive blood culture is drawn, is a potential risk factor for mortality.24 Our patients received antifungal therapy only after blood cultures were reported positive for candidemia. To minimize delay in starting antifungal therapy and reduce mortality, physicians should be able to identify subsets of patients who are at high risk for candidemia so that prophylactic, preemptive and early empirical therapy strategies may be implemented.6
Removal of vascular catheters and atleast 5 days of antifungal therapy have been found to be independently associated with a reduction in mortality.
More importantly than administering antifungal therapy, emphasis on prevention of candidemia can decrease mortality more effectively.25 Compliance with hand hygiene recommendations is mandatory. Guidelines for prevention of CLABSI have recommended implementation of the Central Line bundle.13 Educational programmes must emphasize essential components of these guidelines. Judicious use of antibiotics is another important strategy in the prevention of nosocomial candidemia.
Although this is a prospective study, one of the major limitations of our study is that it is a single institution's experience so results cannot be generalized. Therefore, multicentricstudies are required to identify risk factors. Also, since treatment decisions were made by the attending physician and not based on a controlled protocol, conclusions regarding outcome should be interpreted with caution.
Frequency of candidemia in our population is similar to that reported from other developing countries as is the finding that non-albicans species are more common in this part of the world. None of the patients had received empirical antifungal therapy and mortality was high. Therefore, further studies are required to identify subsets of patients most at risk for candidemia so that early empirical antifungal therapy can be instituted. Fluconazole remains a good choice for antifungal therapy. Most importantly, since the majority of our patients had line related candidemia, one must focus on the prevention of CLABSI as its foremost priority.
We are grateful to Miss RiffatAslam and Dr. Shiyam Sunder Tikmani for their guidance in statistical analysis.
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2. Marchetti O, Bille J, Fluckiger U, Eggimann P, Ruef C, Garbino J, et al. Epidemiology of candidemia in Swiss tertiary care hospitals: secular trends, 1991-2000. Clin Infect Dis 2004; 38: 311-20.
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(Department of Microbiology, Sindh Institute of Urology and Transplantation, Karachi, Pakistan.)
(Department of Infectious Diseases, Sindh Institute of Urology and Transplantation, Karachi, Pakistan.)
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|Publication:||Journal of Pakistan Medical Association|
|Article Type:||Clinical report|
|Date:||Mar 31, 2014|
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