- Email: [email protected]
Long-term epidemiological survey of Candida species: comparison of isolates found in an intensive care unit and in conventional wards
Journal of Hospital Infection (2003) 55, 169–174
www.elsevierhealth.com/journals/jhin
Long-term epidemiological survey of Candida species: comparison of isolates found in an intensive care unit and in conventional wards `sea, F. Antoninia, A. Michel-Nguyenb, M. Leonea,*, J. Albane a M.-C. Blanc-Bimar , C. Martina a
Intensive Care Unit and Anesthesiology, Nord Hospital, Marseilles School of Medicine, Marseilles University Hospital System, Marseilles, France b Laboratory of Bacteriology, Nord Hospital, Marseilles School of Medicine, Marseilles University Hospital System, Marseilles, France Received 2 September 2002; accepted 31 July 2003
KEYWORDS Candida; Hospitalacquired infection; Intensive care unit; Fluconazole
Summary The aim of this study was to compare the distribution of Candida species in patients hospitalized in an intensive care unit (ICU) and in conventional wards. A retrospective analysis was performed covering an 18year period in a 700-bed teaching hospital. Various body sites were investigated in all patients admitted during the study and isolates were identified by microscopic and macroscopic morphology, and by commercially available kits. The susceptibility of strains to amphotericin B and flucytosine was assessed by the ATB-fungusw system, itraconazole and fluconazole by Etestw. No difference was observed between the distribution of Candida species in ICU and in conventional wards. Candida albicans represented about 70% of isolates and Candida glabrata was the second most common species involved in infection or colonization. The small number of C. glabrata resistant to fluconazole suggested this antifungal agent as suitable empirical treatment for non-immunocompromized patients in whom a fungal infection was suspected. Q 2003 The Hospital Infection Society. Published by Elsevier Ltd. All rights reserved.
Introduction There has been a dramatic increase in the incidence of yeast infections within the past two decades1,2 *Corresponding author. Tel.: þ 33-491968650; fax: 33491962818. E-mail address: [email protected], marc.leone@ wanadoo.fr (M. Leone)
and Candida spp. are currently among the most common nosocomial pathogens in intensive care units (ICUs).3 Several investigators have reported that the incidence of infections caused by species other than Candida albicans has increased.4 – 6 Candida glabrata ranks fourth among the Candida species isolated from blood, and the mortality from C. glabrata infection is as high as that reported for C. albicans infections.7,8 Furthermore, candidaemia
0195-6701/$ - see front matter Q 2003 The Hospital Infection Society. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.jhin.2003.07.003
170
has been shown to contribute to prolonged hospitalization and to be an independent determinant for death.9 C. glabrata is of particular importance because of its innately reduced susceptibility to antifungal agents, specifically azoles.5,10 – 12 Adequate empirical treatment may reduce the mortality of septic patients in ICU.13 A knowledge of the species distribution and antifungal susceptibility of Candida species, which are isolated from normally sterile sites in patients hospitalized in wards or in an ICU, will help the choice of empirical treatment. Although there are data to show an increase in multiresistant bacteria in ICU, it is not known whether these are applicable to yeast isolates.14 The present study was conducted to compare the distribution of Candida species and their antifungal susceptibilities, in patients hospitalized either in wards or in an ICU of a single institution during an 18-year period.
M. Leone et al.
positive culture of the tip and sepsis, if present, fully explained by an identified source. For no catheter infection: no growth; or , 1000 cfu of the catheter tip and sepsis, if present, fully explained by another recognized source. Urine samples were obtained through clean-catch voiding or were taken from the catheter with a syringe. All Candida isolates were included. Antifungal prophylaxis was not used during this method. Cultures of blood and normally sterile body sites were identified to species level. The macroscopic and microscopic morphology was examined on Sabouraud glucose agar (bioMe ´rieux) and on Rice agar-Tween (RAT) medium (bioMe ´rieux). Biochemical profiles were obtained using the API Candida systems, and later the Auxacolor (1995) and ID 32C systems (bioMe ´rieux) as recommended by the manufacturer or by conventional methods as required.15,16
Susceptibility testing
Methods Patients Patients admitted to Nord Hospital, a 700-bed tertiary-care teaching hospital between 1980 and 1998, were included retrospectively in the study. Patients admitted to the ICU and conventional wards were studied. The ICU is a 16-bed, individualroom, and admits medical, surgical, and trauma patients. The yeast isolates were isolated from the nose, pharynx, broncho-pulmonary tree, urine, wounds, and catheters. Collection was performed twice a week in ICU patients. Conventional wards included medical wards (departments of internal medicine, respiratory, digestive, heart, infectious, and paediatric diseases) and surgical wards (departments of neurosurgery, digestive surgery, urology, otolaryngology, dental surgery, and orthopaedics). In these wards, specimens were collected at the discretion of the clinical staff when clinically indicated. In 1996, there was the addition of a department of gynaecology and obstetrics, in which post-natal vaginal specimens from parturient vagina were systematically collected. Oropharyngeal, digestive, skin, and vaginal specimens were obtained with a sterile cotton swab. The criteria for catheter-related infections were as follows. For catheter-related infection: a positive culture of the tip without other identified sources of infection, and at least partial resolution of the septic syndrome within 48 h after catheter removal [reduction in body temperature and in white blood cell (WBC) count]. For catheter colonization:
The antifungal susceptibility of C. glabrata was evaluated because of the possibility of resistance. Sixty-three strains of C. glabrata isolated between 1997 and 1998 were used. They were recovered from urine ðN ¼ 28Þ; vagina ðN ¼ 10Þ; pharynx ðN ¼ 7Þ; stomach ðN ¼ 5Þ; skin ðN ¼ 2Þ; and sputum ðN ¼ 11Þ: Candida krusei ATCC 6258 and C. glabrata ATCC 90030 were included as quality control isolates and reference strains, respectively. Susceptibility of isolates to amphotericin B and 5-fluorocytosine was determined using the ATB-Fungusw system (bioMe ´rieux). Fluconazole and itraconazole concentrations inhibiting 90% of isolates (MIC90) were determined using E-test (AB Biodisk, Solna, Sweden) as described elsewhere.17 Statistical comparisons were performed using chi square test and Student’s t-test where appropriate. A P-value , 0.05 was considered significant.
Results The period (1980 – 1998) was divided in four subperiods. The clinical characteristics of the study patients are presented in Table I. No significant changes were observed during the study period. The isolation frequencies of the species of Candida within each sub-period are presented in Table II. Overall, 16625 (68%) isolates were identified as C. albicans. The other species isolated were in part C. glabrata (2298, 9.4%) and Candida tropicalis (2031, 8.3%). The comparison between the frequencies recovered in the ICU and in the other hospital wards within the periods 1984 – 1998 is
Fungal epidemiological survey
171
Table I Clinical characteristics of the patients admitted in intensive care unit during the study period Year Age mean (SD) Male/female ICU days stay mean (SD) Types of patients Medical (%) Surgical (%) Trauma (%) SAPS II mean (SD) Mechanical ventilation (%) Mortality (%)
1980
1985
1990
1995
1998
46 (25) 62/38 6.3 (2.4)
48 (27) 65/35 6.2 (2.8)
46 (26) 64/36 6.9 (3.1)
48 (23) 67/33 6.7 (2.9)
47 (22) 65/35 6.5 (2.7)
38 32 30 –
39 33 28 –
73 23
35 36 29 –
67 25
71 21
40 27 33 48 (23) 75 29
44 20 36 47 (21) 69 27
ICU, intensive care unit; SAPS II, simplified acute physiology score II; SD; standard deviation.
presented in Figure 1. No significant difference was observed between the species isolated in ICU and those isolated in conventional wards. In Table III the species recovered in the ICU and wards according to body site are compared. The differences between the species according to the place of hospitalization (ICU or wards) were not statistically significant. C. albicans was the most common in every body site, irrespective of location. Among the nonalbicans species, C. glabrata predominated, representing 10% of the species. Because of the predominance of C. glabrata among the non-albicans species, we studied the in vitro susceptibility of 63 isolates of C. glabrata to antifungal agents. All strains were susceptible to amphotericin B (MIC90 # 1 mg/mL). Ninety percent of the isolates were susceptible to 5-fluorocytosine (MIC 90 # 2 mg/mL). The MIC90 of isolates of C. glabrata to fluconazole ranged from 2 to 16 mg/mL in 79% of cases. Five isolates (7.9%) were resistant to fluconazole (MIC90 $ 32 mg/mL).
Figure 1 Comparison of the distribution of Candida species between ICU and ward patients. The percentage of each Candida species is represented by black (ICU patients) and grey (ward patients) columns. Above each column, the absolute number of each Candida species is indicated.
Forty-six isolates (73%) had a MIC90 to itraconazole # 2 mg/mL. Four of the five isolates resistant to fluconazole were also resistant to itraconazole.
Discussion The present study analysed the number of isolates of Candida spp. during a period of 18 years in patients hospitalized either in an ICU or conventional wards. The total number of strains was taken into consideration, without distinction between colonization and infection. Although the majority of isolates were C. albicans (68%), the presence of C. glabrata (9.4%) was significant, reaching 11% during the last period. An international surveillance of bloodstream infections due to Candida species SENTRY surveillance programme was conducted in the United States, Canada, Latin America, and Europe over the three-year period from 1997 to 1999.11 C. glabrata was the most common nonC. albicans species in the United States.11 The results of the present study show that C. glabrata is an important nosocomial pathogen, and that the frequency of this species was constant over the study period. These data confirm those of an American study in which C. glabrata was the second most common species isolated, 18 but are at variance with those of Greek study in which C. tropicalis was the most common non-albicans species.19 Multiresistant bacteria are generally more common in ICUs than in conventional wards.20,21 Few data concerning the distribution of yeast species in different sites in the same hospital are available in the literature. A multicentre study of 50 medical centres documented that 10% of C. albicans isolated from the bloodstream of hospitalized patients were resistant to fluconazole.22 It could be hypothesized that the presence of critically-ill patients, the use of invasive devices, and the considerable
951 (3.9) 480 (2.0) 877 (3.6) 1301 (5.3) 2031 (8.2) 2298 (9.4) 16625 (68) Overall
4200 3789 7483 9091 150 (3.6) 128 (3.4) 252 (3.4) 421 (4.6) 112 (2.6) 71 (1.9) 136 (1.8) 161 (1.9) 115 (2.7) 113 (3.0) 307 (4.1) 342 (3.8) (2.7) (6.9) (6.4) (5.0) 109 260 478 454 547 (13.0) 260 (6.9) 539 (7.2) 685 (7.5) 376 (8.9) 287 (7.6) 659 (8.8) 976 (11.0) 2791 (66) 2760 (70) 5112 (68) 6252 (66) 1980–1983 1984–1987 1988–1993 1994–1998
N (%) Candida albicans N (%)
Candida glabrata N (%)
Candida tropicalis N (%)
Candida parapsilosis N (%)
Candida krusei N (%)
Candida kefyr N (%)
Yeasts spp. Species Years
Table II Distribution of Candida species over the study period
24563
M. Leone et al.
Overall
172
administration of antibiotics promote the emergence of particular Candida species. Our results do not support this hypothesis as no difference was observed between the distribution of yeasts in the ICU and in conventional wards. The lack of difference between the two groups of patients is of great interest. This indicates that hospitalization in ICU should not be considered as a risk factor of the emergence of particular Candida species. It should be noted that yeast isolates were collected in a hospital without a dedicated ward for highly immunocompromized patients. Although, various medical and surgical wards did admit immunocompromized patients such as those with malignant conditions and human immunodeficiency virus (HIV) positive patients. There was no department of haematology for patients with bone marrow transplant or leukaemias. The addition in 1996 of a department of gynaecology and obstetrics resulted in more vaginal swab samples, but did not change the relative frequencies of C. albicans and others Candida species. Throughout the study period, C. albicans was predominant and C. glabrata remained the second most common isolate from infection and colonization. The laboratory methods changed during the study period, and there were some advances in isolating some species. However, these did not influence the relative isolation of C. albicans, C. glabrata and C. tropicalis because the combination of morphological and physiological characteristics used from 1980 in our laboratory made it possible to distinguish each species.24 The resistance of C. glabrata to fluconazole is well-recognized. 4,11,12,23,24 C. glabrata represented approximately 12% of all species.11 In our study, resistance to fluconazole was observed in 8% of the cases. Overall, the risk of resistance to fluconazole when a Candida species was present was , 1%. This observation has led us to prescribe fluconazole as empirical treatment when needed. These data are in accordance with those observed in an international study reporting that fluconazole was active in all regions, with 90 to 98% of isolates susceptible to a drug concentration of # 8 mg/mL.11 It is possible that the lack of antifungal resistance is related to the absence of highly immunocompromized patients in our institution. Our use of empirical antifungal treatment should not be extended to immunocompromized patients. Another limitation of the present study is the lack of distinction between colonization and infection. However, knowledge of colonization is of importance in monitoring ICU patients.1 In conclusion, the distribution of Candida species in an ICU and conventional wards during an 18-year
Fungal epidemiological survey
173
Table III Frequency of species recovered in the ICU and in conventional wards, according to body sites from 1980 to 1998 Sites
Candida albicans ICU
Pharynx (%) Bronchi (%) Urine (%) Genital (%) Digestive (%) Nose (%) Blood (%) Device (%) Overall (%) ðnÞ
Candida glabrata Wards
Candida tropicalis ICU
Candida parapsilosis
ICU
65 65 63 73 66 69 54 65
75 68 63 80 67 65 61 66
11 10 13 17 10 8 12 13
8 4 13 13 8 4 11 9
9 9 7 2 6 10 5 7
9 7 10 2 6 7 9 8
3 3 7 0 3 4 12 7
4 7 6 1 5 20 9 12
5 7 5 0 9 4 5 5
5 2 3 1 2 0 2 2
3 3 2 1 2 2 0 2
2 1 2 1 2 1 0 2
65 4624
70 6728
12 853
10 961
7 497
7 672
5 356
5 480
5 356
3 288
2 142
2 192
9.
10.
11.
References 12. 1. Pittet D, Monod M, Suter PM, Freenk E, Auckenthaler R. Candida colonization and subsequent infections in critically ill surgical patients. Ann Surg 1994;220:751—758. 2. Vincent JL, Anaissie E, Bruining H, et al. Epidemiology, diagnosis and treatment of systemic Candida infection in surgical patients under intensive care. Intensive Care Med 1998;24:206—216. 3. Vincent JL, Bihari DJ, Suter PM, et al. The prevalence of nosocomial infection in intensive care units in Europe. Results of the European Prevalence in Intensive Care (EPIC) Study. JAMA 1995;274:639—644. 4. Nguyen MH, Peacock JE, Morris AJ, et al. The changing face of candidemia, emergence of non-Candida albicans species and antifungal resistance. Am J Med 1996;100:617—623. 5. Pfaller MA, Messer SA, Houston A, et al. National epidemiology of mycoses survey: a multicenter study of strain variation and antifungal susceptibility among isolates of Candida species. Diagn Microbiol Infect Dis 1998;31: 289—296. 6. Abi-Said D, Anaissie E, Uzun O, Raad I, Pinzcowski H, Vartivarian S. The epidemiology of hematogenous candidiasis caused by different Candida species. Clin Infect Dis 1997; 24:1122—1128. 7. Beck-Sague CM, Jarvis WR. Secular trends in the epidemiology of nosocomial fungal infections in the United States, 1980—1990. National Nosocomial Infections Surveillance System. J Infect Dis 1993;167:1247—1251. 8. Komshian SV, Uwaydah AK, Sobel JD, Crane LR. Fungemia caused by Candida species and Torulopsis glabrata in the hospitalized patient: frequency, characteristics, and evalu-
13.
14. 15.
16.
17.
18.
19.
20.
ICU
Wards
ICU
Wards
Candida kefyr
Wards
period showed C. albicans was predominant, representing approximately 70% of species overall. C. glabrata was second most common in infection or colonization. No difference was observed between the distribution of species in the ICU and in conventional wards. The low numbers of C. glabrata with a resistance to fluconazole has led to the use of this antifungal agent in the empirical treatment of patients in whom a fungal infection is suspected.
Wards
Candida krusei
ICU
Wards
ation of factors influencing outcome. Rev Infect Dis 1989;11: 379—390. Wey SB, Mori M, Pfaller MA, Woolson RF, Wenzel RP. Hospital-acquired candidemia. The attributable mortality and excess length of stay. Arch Intern Med 1988;148: 2642—2645. Wingard JR. Infections due to resistant Candida species in patients with cancer who are receiving chemotherapy. Clin Infect Dis 1994;19:S49—S53. Pfaller MA, Diekema DJ, Jones RN, et al. International surveillance of bloodstream infections due to Candida species: frequency of occurrence and in vitro susceptibilities to fluconazole, ravuconazole, and voriconazole of isolates collected from 1997 through 1999 in the SENTRY antimicrobial surveillance program. J Clin Microbiol 2001;39: 3254—3259. Baddley JW, Smith AM, Moser SA, Pappas PG. Trends in frequency and susceptibilities of Candida glabrata bloodstream isolates at a university hospital. Diagn Microbiol Infect Dis 2001;39:199—201. Kollef MH, Sherman G, Ward S, Fraser VJ. Inadequate antimicrobial treatment of infections. A risk factor for hospital mortality among critically ill patients. Chest 1999; 115:462—474. Kollef MH, Fraser VJ. Antibiotic resistance in the intensive care unit. Ann Intern Med 2001;134:298—314. Fricker-Hidalgo H, Lebeau B, Kervroedan P, Faure O, Ambroise-Thomas P, Grillot R. Auxacolor, a new commercial system for yeast identification: evaluation of 182 strains comparatively with ID 32C. Ann Biol Clin (Paris) 1995;53: 221—225. Verweij PE, Breuker IM, Rijs AJ, Meis JF. Comparative study of seven commercial yeast identification systems. J Clin Pathol 1999;52:271—273. Colombo AL, Barchiesi F, McGough DA, Fothergill AW, Rinaldi MG. Evaluation of the E Test system versus a microtitre broth method for antifungal susceptibility testing of yeasts against fluconazole and itraconazole. J Antimicrob Chemother 1995;36:93—100. Berrouane YF, Herwaldt LA, Pfaller MA. Trends in antifungal use and epidemiology of nosocomial yeast infections in a university hospital. J Clin Microbiol 1999;37:531—537. Kanellopoulou M, Stamos G, Petinnelli I, et al. Subtyping and antifungal susceptibilities of Candida spp. in the intensive care unit of a Greek general hospital. Int J Antimicrob Agents 2001;18:179—183. Fridkin SK, Steward CD, Edwards JR, et al. Surveillance of
174
antimicrobial use and antimicrobial resistance in U.S. Hospitals: Project ICARE Phase 2. Clin infect Dis 1999;29: 245—252. 21. Fridkin SK. Increasing prevalence of antimicrobial resistance in intensive care units. Crit Care Med 2001;29:N64—N68. 22. Pfaller MA, Jones RN, Messer SA, Edmond MB, Wenzel RP. National surveillance of nosocomial bloodstream infection due to Candida albicans: frequency of occurrence and
M. Leone et al.
antifungal susceptibility in the SCOPE Program. Diagn Microbiol Infect Dis 1998;31:327—332. 23. Rex JH, Rinaldi MG, Pfaller MA. Resistance of Candida species to fluconazole. Antimicrob Agents Chemother 1995; 39:1—8. 24. Sanglard D, Odds FC. Resistance of Candida species to antifungal agents: molecular mechanisms and clinical consequences. Lancet Infect Dis 2002;2:73—85.
www.elsevierhealth.com/journals/jhin
Long-term epidemiological survey of Candida species: comparison of isolates found in an intensive care unit and in conventional wards `sea, F. Antoninia, A. Michel-Nguyenb, M. Leonea,*, J. Albane a M.-C. Blanc-Bimar , C. Martina a
Intensive Care Unit and Anesthesiology, Nord Hospital, Marseilles School of Medicine, Marseilles University Hospital System, Marseilles, France b Laboratory of Bacteriology, Nord Hospital, Marseilles School of Medicine, Marseilles University Hospital System, Marseilles, France Received 2 September 2002; accepted 31 July 2003
KEYWORDS Candida; Hospitalacquired infection; Intensive care unit; Fluconazole
Summary The aim of this study was to compare the distribution of Candida species in patients hospitalized in an intensive care unit (ICU) and in conventional wards. A retrospective analysis was performed covering an 18year period in a 700-bed teaching hospital. Various body sites were investigated in all patients admitted during the study and isolates were identified by microscopic and macroscopic morphology, and by commercially available kits. The susceptibility of strains to amphotericin B and flucytosine was assessed by the ATB-fungusw system, itraconazole and fluconazole by Etestw. No difference was observed between the distribution of Candida species in ICU and in conventional wards. Candida albicans represented about 70% of isolates and Candida glabrata was the second most common species involved in infection or colonization. The small number of C. glabrata resistant to fluconazole suggested this antifungal agent as suitable empirical treatment for non-immunocompromized patients in whom a fungal infection was suspected. Q 2003 The Hospital Infection Society. Published by Elsevier Ltd. All rights reserved.
Introduction There has been a dramatic increase in the incidence of yeast infections within the past two decades1,2 *Corresponding author. Tel.: þ 33-491968650; fax: 33491962818. E-mail address: [email protected], marc.leone@ wanadoo.fr (M. Leone)
and Candida spp. are currently among the most common nosocomial pathogens in intensive care units (ICUs).3 Several investigators have reported that the incidence of infections caused by species other than Candida albicans has increased.4 – 6 Candida glabrata ranks fourth among the Candida species isolated from blood, and the mortality from C. glabrata infection is as high as that reported for C. albicans infections.7,8 Furthermore, candidaemia
0195-6701/$ - see front matter Q 2003 The Hospital Infection Society. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.jhin.2003.07.003
170
has been shown to contribute to prolonged hospitalization and to be an independent determinant for death.9 C. glabrata is of particular importance because of its innately reduced susceptibility to antifungal agents, specifically azoles.5,10 – 12 Adequate empirical treatment may reduce the mortality of septic patients in ICU.13 A knowledge of the species distribution and antifungal susceptibility of Candida species, which are isolated from normally sterile sites in patients hospitalized in wards or in an ICU, will help the choice of empirical treatment. Although there are data to show an increase in multiresistant bacteria in ICU, it is not known whether these are applicable to yeast isolates.14 The present study was conducted to compare the distribution of Candida species and their antifungal susceptibilities, in patients hospitalized either in wards or in an ICU of a single institution during an 18-year period.
M. Leone et al.
positive culture of the tip and sepsis, if present, fully explained by an identified source. For no catheter infection: no growth; or , 1000 cfu of the catheter tip and sepsis, if present, fully explained by another recognized source. Urine samples were obtained through clean-catch voiding or were taken from the catheter with a syringe. All Candida isolates were included. Antifungal prophylaxis was not used during this method. Cultures of blood and normally sterile body sites were identified to species level. The macroscopic and microscopic morphology was examined on Sabouraud glucose agar (bioMe ´rieux) and on Rice agar-Tween (RAT) medium (bioMe ´rieux). Biochemical profiles were obtained using the API Candida systems, and later the Auxacolor (1995) and ID 32C systems (bioMe ´rieux) as recommended by the manufacturer or by conventional methods as required.15,16
Susceptibility testing
Methods Patients Patients admitted to Nord Hospital, a 700-bed tertiary-care teaching hospital between 1980 and 1998, were included retrospectively in the study. Patients admitted to the ICU and conventional wards were studied. The ICU is a 16-bed, individualroom, and admits medical, surgical, and trauma patients. The yeast isolates were isolated from the nose, pharynx, broncho-pulmonary tree, urine, wounds, and catheters. Collection was performed twice a week in ICU patients. Conventional wards included medical wards (departments of internal medicine, respiratory, digestive, heart, infectious, and paediatric diseases) and surgical wards (departments of neurosurgery, digestive surgery, urology, otolaryngology, dental surgery, and orthopaedics). In these wards, specimens were collected at the discretion of the clinical staff when clinically indicated. In 1996, there was the addition of a department of gynaecology and obstetrics, in which post-natal vaginal specimens from parturient vagina were systematically collected. Oropharyngeal, digestive, skin, and vaginal specimens were obtained with a sterile cotton swab. The criteria for catheter-related infections were as follows. For catheter-related infection: a positive culture of the tip without other identified sources of infection, and at least partial resolution of the septic syndrome within 48 h after catheter removal [reduction in body temperature and in white blood cell (WBC) count]. For catheter colonization:
The antifungal susceptibility of C. glabrata was evaluated because of the possibility of resistance. Sixty-three strains of C. glabrata isolated between 1997 and 1998 were used. They were recovered from urine ðN ¼ 28Þ; vagina ðN ¼ 10Þ; pharynx ðN ¼ 7Þ; stomach ðN ¼ 5Þ; skin ðN ¼ 2Þ; and sputum ðN ¼ 11Þ: Candida krusei ATCC 6258 and C. glabrata ATCC 90030 were included as quality control isolates and reference strains, respectively. Susceptibility of isolates to amphotericin B and 5-fluorocytosine was determined using the ATB-Fungusw system (bioMe ´rieux). Fluconazole and itraconazole concentrations inhibiting 90% of isolates (MIC90) were determined using E-test (AB Biodisk, Solna, Sweden) as described elsewhere.17 Statistical comparisons were performed using chi square test and Student’s t-test where appropriate. A P-value , 0.05 was considered significant.
Results The period (1980 – 1998) was divided in four subperiods. The clinical characteristics of the study patients are presented in Table I. No significant changes were observed during the study period. The isolation frequencies of the species of Candida within each sub-period are presented in Table II. Overall, 16625 (68%) isolates were identified as C. albicans. The other species isolated were in part C. glabrata (2298, 9.4%) and Candida tropicalis (2031, 8.3%). The comparison between the frequencies recovered in the ICU and in the other hospital wards within the periods 1984 – 1998 is
Fungal epidemiological survey
171
Table I Clinical characteristics of the patients admitted in intensive care unit during the study period Year Age mean (SD) Male/female ICU days stay mean (SD) Types of patients Medical (%) Surgical (%) Trauma (%) SAPS II mean (SD) Mechanical ventilation (%) Mortality (%)
1980
1985
1990
1995
1998
46 (25) 62/38 6.3 (2.4)
48 (27) 65/35 6.2 (2.8)
46 (26) 64/36 6.9 (3.1)
48 (23) 67/33 6.7 (2.9)
47 (22) 65/35 6.5 (2.7)
38 32 30 –
39 33 28 –
73 23
35 36 29 –
67 25
71 21
40 27 33 48 (23) 75 29
44 20 36 47 (21) 69 27
ICU, intensive care unit; SAPS II, simplified acute physiology score II; SD; standard deviation.
presented in Figure 1. No significant difference was observed between the species isolated in ICU and those isolated in conventional wards. In Table III the species recovered in the ICU and wards according to body site are compared. The differences between the species according to the place of hospitalization (ICU or wards) were not statistically significant. C. albicans was the most common in every body site, irrespective of location. Among the nonalbicans species, C. glabrata predominated, representing 10% of the species. Because of the predominance of C. glabrata among the non-albicans species, we studied the in vitro susceptibility of 63 isolates of C. glabrata to antifungal agents. All strains were susceptible to amphotericin B (MIC90 # 1 mg/mL). Ninety percent of the isolates were susceptible to 5-fluorocytosine (MIC 90 # 2 mg/mL). The MIC90 of isolates of C. glabrata to fluconazole ranged from 2 to 16 mg/mL in 79% of cases. Five isolates (7.9%) were resistant to fluconazole (MIC90 $ 32 mg/mL).
Figure 1 Comparison of the distribution of Candida species between ICU and ward patients. The percentage of each Candida species is represented by black (ICU patients) and grey (ward patients) columns. Above each column, the absolute number of each Candida species is indicated.
Forty-six isolates (73%) had a MIC90 to itraconazole # 2 mg/mL. Four of the five isolates resistant to fluconazole were also resistant to itraconazole.
Discussion The present study analysed the number of isolates of Candida spp. during a period of 18 years in patients hospitalized either in an ICU or conventional wards. The total number of strains was taken into consideration, without distinction between colonization and infection. Although the majority of isolates were C. albicans (68%), the presence of C. glabrata (9.4%) was significant, reaching 11% during the last period. An international surveillance of bloodstream infections due to Candida species SENTRY surveillance programme was conducted in the United States, Canada, Latin America, and Europe over the three-year period from 1997 to 1999.11 C. glabrata was the most common nonC. albicans species in the United States.11 The results of the present study show that C. glabrata is an important nosocomial pathogen, and that the frequency of this species was constant over the study period. These data confirm those of an American study in which C. glabrata was the second most common species isolated, 18 but are at variance with those of Greek study in which C. tropicalis was the most common non-albicans species.19 Multiresistant bacteria are generally more common in ICUs than in conventional wards.20,21 Few data concerning the distribution of yeast species in different sites in the same hospital are available in the literature. A multicentre study of 50 medical centres documented that 10% of C. albicans isolated from the bloodstream of hospitalized patients were resistant to fluconazole.22 It could be hypothesized that the presence of critically-ill patients, the use of invasive devices, and the considerable
951 (3.9) 480 (2.0) 877 (3.6) 1301 (5.3) 2031 (8.2) 2298 (9.4) 16625 (68) Overall
4200 3789 7483 9091 150 (3.6) 128 (3.4) 252 (3.4) 421 (4.6) 112 (2.6) 71 (1.9) 136 (1.8) 161 (1.9) 115 (2.7) 113 (3.0) 307 (4.1) 342 (3.8) (2.7) (6.9) (6.4) (5.0) 109 260 478 454 547 (13.0) 260 (6.9) 539 (7.2) 685 (7.5) 376 (8.9) 287 (7.6) 659 (8.8) 976 (11.0) 2791 (66) 2760 (70) 5112 (68) 6252 (66) 1980–1983 1984–1987 1988–1993 1994–1998
N (%) Candida albicans N (%)
Candida glabrata N (%)
Candida tropicalis N (%)
Candida parapsilosis N (%)
Candida krusei N (%)
Candida kefyr N (%)
Yeasts spp. Species Years
Table II Distribution of Candida species over the study period
24563
M. Leone et al.
Overall
172
administration of antibiotics promote the emergence of particular Candida species. Our results do not support this hypothesis as no difference was observed between the distribution of yeasts in the ICU and in conventional wards. The lack of difference between the two groups of patients is of great interest. This indicates that hospitalization in ICU should not be considered as a risk factor of the emergence of particular Candida species. It should be noted that yeast isolates were collected in a hospital without a dedicated ward for highly immunocompromized patients. Although, various medical and surgical wards did admit immunocompromized patients such as those with malignant conditions and human immunodeficiency virus (HIV) positive patients. There was no department of haematology for patients with bone marrow transplant or leukaemias. The addition in 1996 of a department of gynaecology and obstetrics resulted in more vaginal swab samples, but did not change the relative frequencies of C. albicans and others Candida species. Throughout the study period, C. albicans was predominant and C. glabrata remained the second most common isolate from infection and colonization. The laboratory methods changed during the study period, and there were some advances in isolating some species. However, these did not influence the relative isolation of C. albicans, C. glabrata and C. tropicalis because the combination of morphological and physiological characteristics used from 1980 in our laboratory made it possible to distinguish each species.24 The resistance of C. glabrata to fluconazole is well-recognized. 4,11,12,23,24 C. glabrata represented approximately 12% of all species.11 In our study, resistance to fluconazole was observed in 8% of the cases. Overall, the risk of resistance to fluconazole when a Candida species was present was , 1%. This observation has led us to prescribe fluconazole as empirical treatment when needed. These data are in accordance with those observed in an international study reporting that fluconazole was active in all regions, with 90 to 98% of isolates susceptible to a drug concentration of # 8 mg/mL.11 It is possible that the lack of antifungal resistance is related to the absence of highly immunocompromized patients in our institution. Our use of empirical antifungal treatment should not be extended to immunocompromized patients. Another limitation of the present study is the lack of distinction between colonization and infection. However, knowledge of colonization is of importance in monitoring ICU patients.1 In conclusion, the distribution of Candida species in an ICU and conventional wards during an 18-year
Fungal epidemiological survey
173
Table III Frequency of species recovered in the ICU and in conventional wards, according to body sites from 1980 to 1998 Sites
Candida albicans ICU
Pharynx (%) Bronchi (%) Urine (%) Genital (%) Digestive (%) Nose (%) Blood (%) Device (%) Overall (%) ðnÞ
Candida glabrata Wards
Candida tropicalis ICU
Candida parapsilosis
ICU
65 65 63 73 66 69 54 65
75 68 63 80 67 65 61 66
11 10 13 17 10 8 12 13
8 4 13 13 8 4 11 9
9 9 7 2 6 10 5 7
9 7 10 2 6 7 9 8
3 3 7 0 3 4 12 7
4 7 6 1 5 20 9 12
5 7 5 0 9 4 5 5
5 2 3 1 2 0 2 2
3 3 2 1 2 2 0 2
2 1 2 1 2 1 0 2
65 4624
70 6728
12 853
10 961
7 497
7 672
5 356
5 480
5 356
3 288
2 142
2 192
9.
10.
11.
References 12. 1. Pittet D, Monod M, Suter PM, Freenk E, Auckenthaler R. Candida colonization and subsequent infections in critically ill surgical patients. Ann Surg 1994;220:751—758. 2. Vincent JL, Anaissie E, Bruining H, et al. Epidemiology, diagnosis and treatment of systemic Candida infection in surgical patients under intensive care. Intensive Care Med 1998;24:206—216. 3. Vincent JL, Bihari DJ, Suter PM, et al. The prevalence of nosocomial infection in intensive care units in Europe. Results of the European Prevalence in Intensive Care (EPIC) Study. JAMA 1995;274:639—644. 4. Nguyen MH, Peacock JE, Morris AJ, et al. The changing face of candidemia, emergence of non-Candida albicans species and antifungal resistance. Am J Med 1996;100:617—623. 5. Pfaller MA, Messer SA, Houston A, et al. National epidemiology of mycoses survey: a multicenter study of strain variation and antifungal susceptibility among isolates of Candida species. Diagn Microbiol Infect Dis 1998;31: 289—296. 6. Abi-Said D, Anaissie E, Uzun O, Raad I, Pinzcowski H, Vartivarian S. The epidemiology of hematogenous candidiasis caused by different Candida species. Clin Infect Dis 1997; 24:1122—1128. 7. Beck-Sague CM, Jarvis WR. Secular trends in the epidemiology of nosocomial fungal infections in the United States, 1980—1990. National Nosocomial Infections Surveillance System. J Infect Dis 1993;167:1247—1251. 8. Komshian SV, Uwaydah AK, Sobel JD, Crane LR. Fungemia caused by Candida species and Torulopsis glabrata in the hospitalized patient: frequency, characteristics, and evalu-
13.
14. 15.
16.
17.
18.
19.
20.
ICU
Wards
ICU
Wards
Candida kefyr
Wards
period showed C. albicans was predominant, representing approximately 70% of species overall. C. glabrata was second most common in infection or colonization. No difference was observed between the distribution of species in the ICU and in conventional wards. The low numbers of C. glabrata with a resistance to fluconazole has led to the use of this antifungal agent in the empirical treatment of patients in whom a fungal infection is suspected.
Wards
Candida krusei
ICU
Wards
ation of factors influencing outcome. Rev Infect Dis 1989;11: 379—390. Wey SB, Mori M, Pfaller MA, Woolson RF, Wenzel RP. Hospital-acquired candidemia. The attributable mortality and excess length of stay. Arch Intern Med 1988;148: 2642—2645. Wingard JR. Infections due to resistant Candida species in patients with cancer who are receiving chemotherapy. Clin Infect Dis 1994;19:S49—S53. Pfaller MA, Diekema DJ, Jones RN, et al. International surveillance of bloodstream infections due to Candida species: frequency of occurrence and in vitro susceptibilities to fluconazole, ravuconazole, and voriconazole of isolates collected from 1997 through 1999 in the SENTRY antimicrobial surveillance program. J Clin Microbiol 2001;39: 3254—3259. Baddley JW, Smith AM, Moser SA, Pappas PG. Trends in frequency and susceptibilities of Candida glabrata bloodstream isolates at a university hospital. Diagn Microbiol Infect Dis 2001;39:199—201. Kollef MH, Sherman G, Ward S, Fraser VJ. Inadequate antimicrobial treatment of infections. A risk factor for hospital mortality among critically ill patients. Chest 1999; 115:462—474. Kollef MH, Fraser VJ. Antibiotic resistance in the intensive care unit. Ann Intern Med 2001;134:298—314. Fricker-Hidalgo H, Lebeau B, Kervroedan P, Faure O, Ambroise-Thomas P, Grillot R. Auxacolor, a new commercial system for yeast identification: evaluation of 182 strains comparatively with ID 32C. Ann Biol Clin (Paris) 1995;53: 221—225. Verweij PE, Breuker IM, Rijs AJ, Meis JF. Comparative study of seven commercial yeast identification systems. J Clin Pathol 1999;52:271—273. Colombo AL, Barchiesi F, McGough DA, Fothergill AW, Rinaldi MG. Evaluation of the E Test system versus a microtitre broth method for antifungal susceptibility testing of yeasts against fluconazole and itraconazole. J Antimicrob Chemother 1995;36:93—100. Berrouane YF, Herwaldt LA, Pfaller MA. Trends in antifungal use and epidemiology of nosocomial yeast infections in a university hospital. J Clin Microbiol 1999;37:531—537. Kanellopoulou M, Stamos G, Petinnelli I, et al. Subtyping and antifungal susceptibilities of Candida spp. in the intensive care unit of a Greek general hospital. Int J Antimicrob Agents 2001;18:179—183. Fridkin SK, Steward CD, Edwards JR, et al. Surveillance of
174
antimicrobial use and antimicrobial resistance in U.S. Hospitals: Project ICARE Phase 2. Clin infect Dis 1999;29: 245—252. 21. Fridkin SK. Increasing prevalence of antimicrobial resistance in intensive care units. Crit Care Med 2001;29:N64—N68. 22. Pfaller MA, Jones RN, Messer SA, Edmond MB, Wenzel RP. National surveillance of nosocomial bloodstream infection due to Candida albicans: frequency of occurrence and
M. Leone et al.
antifungal susceptibility in the SCOPE Program. Diagn Microbiol Infect Dis 1998;31:327—332. 23. Rex JH, Rinaldi MG, Pfaller MA. Resistance of Candida species to fluconazole. Antimicrob Agents Chemother 1995; 39:1—8. 24. Sanglard D, Odds FC. Resistance of Candida species to antifungal agents: molecular mechanisms and clinical consequences. Lancet Infect Dis 2002;2:73—85.