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Characterization of enterococci from paediatric enterococcal infections—hospital-based study in India
International Congress Series 1289 (2006) 58 – 61
www.ics-elsevier.com
Characterization of enterococci from paediatric enterococcal infections—hospital-based study in India A. Lakshmy a,*, V.K. Srivastava a, R. Dutta a, G. Mehta a, A.K. Dutta b a
Department of Microbiology, Lady Hardinge Medical College, New Delhi-110001, India b Department of Paediatrics, Kalawati Saran Children’s Hospital, India
Abstract. Eighty-eight percent of paediatric enterococcal isolates recovered from Kalawati Saran Children’s Hospital during 8 months period in 2004 were Enterococcus casseliflavus. This species was recovered predominantly from children with diseases of central nervous system, respiratory and gastrointestinal tract infections and sepsis. Resistance to multiple antibiotics was noted. However all isolates were sensitive to vancomycin. D 2005 Elsevier B.V. All rights reserved. Keywords: E. casseliflavus; Enterococcus spp.; CNS; CVS
1. Introduction Enterococci are ubiquitous and are normal inhabitants of the gastrointestinal tract (GIT) of humans and animals. However, they have recently emerged as a leading cause of nosocomial and community acquired bacteremia, urinary tract infections, surgical wound infections, pelvic infections, intra-abdominal infections and are rare cases of meningitis [1,2]. In recent years there has been an increase in incidence of multiple drug resistant and vancomycin resistant enterococci, especially E. faecalis and E. faecium that are currently responsible for approximately 12% of all nosocomial
* Corresponding author. Tel.: +91 11 23369956. E-mail address: [email protected] (A. Lakshmy). 0531-5131/ D 2005 Elsevier B.V. All rights reserved. doi:10.1016/j.ics.2005.11.075
A. Lakshmy et al. / International Congress Series 1289 (2006) 58–61
59
infection in the USA [2]. The use of various intravascular devices and the intensive use of broad spectrum antibiotics in hospitals exerts a selective pressure favouring the growth of intrinsically drug-resistant commensal organisms like enterococci Currently 23 species of enterococci recovered from humans have been identified. E. faecalis accounts for 80–90% Enterococcal infections with E. faecium being responsible for 10– 15% [2]. Previous studies from India have reported E. faecalis and E. faecium as the only prevalent species [3]. Only few reports or studies of other species of enterococci are available from India. The aim of the present study was to find out the prevalence of Enterococcus spp. causing infections in children and determine their antibiotic sensitivity pattern to the commonly used antibiotics. 2. Materials and methods A total of 80 isolates of Enterococcus spp. obtained during January 2004–August 2004 from children (0–14 years) admitted to KSCH, a 350-bedded tertiary care hospital at New Delhi were included in the study. The study was carried out at the Department of Microbiology, Lady Hardinge Medical College, New Delhi. The clinical isolates of enterococci were obtained from cerebrospinal fluid (66), ascitic fluid (2), bronchioalveolar lavage (2), endotracheal tube tips (2), central venous line tip (1), pus (2), peritoneal dialysis fluid (3), and pleural fluid (2). The study group comprised of 22 neonates, 28 infants, 22 children in the age group of 1–5 years and 8 children N5 years. Fifty-two of these children were male and 22 were female. 2.1. Conventional phenotypic and physiological characterization of enterococci The extensive phenotypic and physiological characterization of enterococci was carried out by conventional biochemical identification scheme of Facklam and Collins [4,5]. 2.2. Antibiotic susceptibility testing The antibiotic sensitivity patterns of the isolates were performed by Kirby Bauer disk diffusion method on Muller Hinton Agar according to NCCLS guidelines [6] with disks (Hi Media, Bombay, India) for the following antibiotics: Amikacin (Ak) 30 Ag, Cotrimoxazole (Co) 25 Ag, Ciprofloxacin (Cf) 5 Ag, Erythromycin (E) 15 Ag, Gentamicin (G) 10 Ag, Penicillin (P) 10 units and Vancomycin (Va) 30 Ag. Control strains were included for quality check for the assays. 3. Results Among the 80 isolates biotyped, E. casseliflavus (70), E. faecalis var Gr. II. (1) and III (7) and Enterococcus (2) were identified. On correlating with the clinical presentation it was observed that 37 out of 80 strains of Enterococcus spp. were obtained from children presenting with involvement of central nervous system (CNS) followed by, respiratory tract (15), GIT (12) and sepsis (10). Excretory and cardiovascular system (CVS) were involved only in 4 and 2 children, respectively, Enterococcus spp. other than Enterococcus casseliflavus were more common from patients with respiratory and GIT infections.
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A. Lakshmy et al. / International Congress Series 1289 (2006) 58–61
Table 1 Resistance pattern of Enterococcus spp. to the commonly used antibiotics System
No. of isolates
No. of isolates resistant to antibiotics Ak
Cf
CO
E
G
P
Va
Respiratory Gastrointestinal CNS Excretory CVS Circulatory (sepsis) Total
15 12 37 4 2 10 80
10 11 28 3 2 7 61
4 8 10 3 1 6 32
11 9 31 4 1 9 65
9 10 32 4 2 10 67
8 8 29 4 2 8 59
13 11 35 4 2 10 75
0 0 0 0 0 0 0
Ak: Amikacin, Co: Cotrimoxazole, Cf: Ciprofloxacin, E: Erythromycin, G: Gentamicin P: Penicillin, Va: Vancomycin.
Only 3 strains were found to be susceptible to all the 6 antibiotics tested. None of the 80 strains were found to be resistant to vancomycin (Table 1). The maximum resistance was observed for P (93.3%) followed by E (86.3%), Co (81.3%), Ak (76.3%) and G (73.8%) and least Ci (40.0%) (Table 1 and Fig. 1). The sensitivity patterns of other Enterococcal spp. were different. 4. Discussion In the present study we have observed the emergence of E. casseliflavus (87.5%) among the clinical enterococcal isolates. On correlating the Enterococcus spp. with the clinical presentation in children, the predominance of E. casseliflavus was observed in 47.1% of the children with involvement of CNS followed by respiratory tract (17.1%), sepsis (14.3%), GIT (12.9%), excretory (5.7%) and CVS (2.9%). All strains were vancomycin sensitive. E. faecalis and E. faecium are currently responsible for approximately 12.0% of all nosocomial infection in the USA. The number of other species of enterococci reported from clinical sources are b5% [2]. This may not reflect the true incidence rate as methods for detailed identification of enterococci are not widely utilized routinely.
Fig. 1. The percentage of resistance of E. casseliflavus and other Enterococcus spp. to the commonly used antibiotics.
A. Lakshmy et al. / International Congress Series 1289 (2006) 58–61
61
Enterococcal infections of the CNS are quite rare and have been reported in patients with neurological conditions, head trauma, shunt devices or CSF leakage but may also occur as spontaneous infection complicating remote enterococcal infections such as endocarditis, pyelonephritis, etc. [7]. Although molecular epidemiological studies have not been done to compare the genetic similarities of these isolates the occurrence of most of the infections N48 h of stay suggest the possible nosocomial origin. To the best of our knowledge this is the fist report in which we have isolated a large number of E. casseliflavus strains from CSF from children and the fifth documented evidence so far with a motile Enterococcus spp. The study highlights the importance of accurately identifying Enterococcus spp. at the species level which is required for epidemiological purposes to detect the existence of motile Enterococcus species like E. casseliflavus and E. gallinarum besides E. faecalis and E. faecium which can cause serious human infections. The present study shows the emergence of E. casseliflavus showing multiple drug resistance (MDR) to the commonly used antibiotics. Effective measures should be taken to control the emergence of MDR Enterococcal strains in the community and hospital environment. References [1] R.C. Mollering Jr., Vancomycin resistant enterococci, Clin. Infect. Dis. 26 (1998) 1196 – 1199. [2] National Nosocomial Infections (NNIS) report, Am. J. Infect. Control 25 (1997) 477 – 478. [3] M. Nischa, R. Macadam, Biochemical spectrum and haemolytic activity in enterococci, Indian J. Med. Microbiol. 14 (1996) 205 – 208. [4] R.R. Facklam, M.D. Collins, Identification of Enterococcus species isolated from human infections by a conventional test scheme, J. Clin. Microbiol. 27 (1989) 731 – 734. [5] R.R. Facklam, D.F. Sahn, L.M. Teixeira, Enterococcus, in: P.R. Murray, E.J. Baron, M.A. Pfaller, F.C. Tenover, R.H. Yolken (Eds.), Manual of Clinical Microbiology, 7th ed., American Society for Microbiology, Washington DC, 1999, pp. 297 – 315. [6] National Committee for Clinical Laboratory Standard. Methods for dilution antimicrobial susceptibility tests for bacteria that grow aerobically Approved Standard. 5th ed. Wayne (PA): NCCLS 2000.Document M7-A5, 27. [7] V. Pintada, et al., Enterococcal meningitis: a clinical study of 39 cases and r review of the literature, Medicine (Baltimore) 82 (2003) 346 – 364.
www.ics-elsevier.com
Characterization of enterococci from paediatric enterococcal infections—hospital-based study in India A. Lakshmy a,*, V.K. Srivastava a, R. Dutta a, G. Mehta a, A.K. Dutta b a
Department of Microbiology, Lady Hardinge Medical College, New Delhi-110001, India b Department of Paediatrics, Kalawati Saran Children’s Hospital, India
Abstract. Eighty-eight percent of paediatric enterococcal isolates recovered from Kalawati Saran Children’s Hospital during 8 months period in 2004 were Enterococcus casseliflavus. This species was recovered predominantly from children with diseases of central nervous system, respiratory and gastrointestinal tract infections and sepsis. Resistance to multiple antibiotics was noted. However all isolates were sensitive to vancomycin. D 2005 Elsevier B.V. All rights reserved. Keywords: E. casseliflavus; Enterococcus spp.; CNS; CVS
1. Introduction Enterococci are ubiquitous and are normal inhabitants of the gastrointestinal tract (GIT) of humans and animals. However, they have recently emerged as a leading cause of nosocomial and community acquired bacteremia, urinary tract infections, surgical wound infections, pelvic infections, intra-abdominal infections and are rare cases of meningitis [1,2]. In recent years there has been an increase in incidence of multiple drug resistant and vancomycin resistant enterococci, especially E. faecalis and E. faecium that are currently responsible for approximately 12% of all nosocomial
* Corresponding author. Tel.: +91 11 23369956. E-mail address: [email protected] (A. Lakshmy). 0531-5131/ D 2005 Elsevier B.V. All rights reserved. doi:10.1016/j.ics.2005.11.075
A. Lakshmy et al. / International Congress Series 1289 (2006) 58–61
59
infection in the USA [2]. The use of various intravascular devices and the intensive use of broad spectrum antibiotics in hospitals exerts a selective pressure favouring the growth of intrinsically drug-resistant commensal organisms like enterococci Currently 23 species of enterococci recovered from humans have been identified. E. faecalis accounts for 80–90% Enterococcal infections with E. faecium being responsible for 10– 15% [2]. Previous studies from India have reported E. faecalis and E. faecium as the only prevalent species [3]. Only few reports or studies of other species of enterococci are available from India. The aim of the present study was to find out the prevalence of Enterococcus spp. causing infections in children and determine their antibiotic sensitivity pattern to the commonly used antibiotics. 2. Materials and methods A total of 80 isolates of Enterococcus spp. obtained during January 2004–August 2004 from children (0–14 years) admitted to KSCH, a 350-bedded tertiary care hospital at New Delhi were included in the study. The study was carried out at the Department of Microbiology, Lady Hardinge Medical College, New Delhi. The clinical isolates of enterococci were obtained from cerebrospinal fluid (66), ascitic fluid (2), bronchioalveolar lavage (2), endotracheal tube tips (2), central venous line tip (1), pus (2), peritoneal dialysis fluid (3), and pleural fluid (2). The study group comprised of 22 neonates, 28 infants, 22 children in the age group of 1–5 years and 8 children N5 years. Fifty-two of these children were male and 22 were female. 2.1. Conventional phenotypic and physiological characterization of enterococci The extensive phenotypic and physiological characterization of enterococci was carried out by conventional biochemical identification scheme of Facklam and Collins [4,5]. 2.2. Antibiotic susceptibility testing The antibiotic sensitivity patterns of the isolates were performed by Kirby Bauer disk diffusion method on Muller Hinton Agar according to NCCLS guidelines [6] with disks (Hi Media, Bombay, India) for the following antibiotics: Amikacin (Ak) 30 Ag, Cotrimoxazole (Co) 25 Ag, Ciprofloxacin (Cf) 5 Ag, Erythromycin (E) 15 Ag, Gentamicin (G) 10 Ag, Penicillin (P) 10 units and Vancomycin (Va) 30 Ag. Control strains were included for quality check for the assays. 3. Results Among the 80 isolates biotyped, E. casseliflavus (70), E. faecalis var Gr. II. (1) and III (7) and Enterococcus (2) were identified. On correlating with the clinical presentation it was observed that 37 out of 80 strains of Enterococcus spp. were obtained from children presenting with involvement of central nervous system (CNS) followed by, respiratory tract (15), GIT (12) and sepsis (10). Excretory and cardiovascular system (CVS) were involved only in 4 and 2 children, respectively, Enterococcus spp. other than Enterococcus casseliflavus were more common from patients with respiratory and GIT infections.
60
A. Lakshmy et al. / International Congress Series 1289 (2006) 58–61
Table 1 Resistance pattern of Enterococcus spp. to the commonly used antibiotics System
No. of isolates
No. of isolates resistant to antibiotics Ak
Cf
CO
E
G
P
Va
Respiratory Gastrointestinal CNS Excretory CVS Circulatory (sepsis) Total
15 12 37 4 2 10 80
10 11 28 3 2 7 61
4 8 10 3 1 6 32
11 9 31 4 1 9 65
9 10 32 4 2 10 67
8 8 29 4 2 8 59
13 11 35 4 2 10 75
0 0 0 0 0 0 0
Ak: Amikacin, Co: Cotrimoxazole, Cf: Ciprofloxacin, E: Erythromycin, G: Gentamicin P: Penicillin, Va: Vancomycin.
Only 3 strains were found to be susceptible to all the 6 antibiotics tested. None of the 80 strains were found to be resistant to vancomycin (Table 1). The maximum resistance was observed for P (93.3%) followed by E (86.3%), Co (81.3%), Ak (76.3%) and G (73.8%) and least Ci (40.0%) (Table 1 and Fig. 1). The sensitivity patterns of other Enterococcal spp. were different. 4. Discussion In the present study we have observed the emergence of E. casseliflavus (87.5%) among the clinical enterococcal isolates. On correlating the Enterococcus spp. with the clinical presentation in children, the predominance of E. casseliflavus was observed in 47.1% of the children with involvement of CNS followed by respiratory tract (17.1%), sepsis (14.3%), GIT (12.9%), excretory (5.7%) and CVS (2.9%). All strains were vancomycin sensitive. E. faecalis and E. faecium are currently responsible for approximately 12.0% of all nosocomial infection in the USA. The number of other species of enterococci reported from clinical sources are b5% [2]. This may not reflect the true incidence rate as methods for detailed identification of enterococci are not widely utilized routinely.
Fig. 1. The percentage of resistance of E. casseliflavus and other Enterococcus spp. to the commonly used antibiotics.
A. Lakshmy et al. / International Congress Series 1289 (2006) 58–61
61
Enterococcal infections of the CNS are quite rare and have been reported in patients with neurological conditions, head trauma, shunt devices or CSF leakage but may also occur as spontaneous infection complicating remote enterococcal infections such as endocarditis, pyelonephritis, etc. [7]. Although molecular epidemiological studies have not been done to compare the genetic similarities of these isolates the occurrence of most of the infections N48 h of stay suggest the possible nosocomial origin. To the best of our knowledge this is the fist report in which we have isolated a large number of E. casseliflavus strains from CSF from children and the fifth documented evidence so far with a motile Enterococcus spp. The study highlights the importance of accurately identifying Enterococcus spp. at the species level which is required for epidemiological purposes to detect the existence of motile Enterococcus species like E. casseliflavus and E. gallinarum besides E. faecalis and E. faecium which can cause serious human infections. The present study shows the emergence of E. casseliflavus showing multiple drug resistance (MDR) to the commonly used antibiotics. Effective measures should be taken to control the emergence of MDR Enterococcal strains in the community and hospital environment. References [1] R.C. Mollering Jr., Vancomycin resistant enterococci, Clin. Infect. Dis. 26 (1998) 1196 – 1199. [2] National Nosocomial Infections (NNIS) report, Am. J. Infect. Control 25 (1997) 477 – 478. [3] M. Nischa, R. Macadam, Biochemical spectrum and haemolytic activity in enterococci, Indian J. Med. Microbiol. 14 (1996) 205 – 208. [4] R.R. Facklam, M.D. Collins, Identification of Enterococcus species isolated from human infections by a conventional test scheme, J. Clin. Microbiol. 27 (1989) 731 – 734. [5] R.R. Facklam, D.F. Sahn, L.M. Teixeira, Enterococcus, in: P.R. Murray, E.J. Baron, M.A. Pfaller, F.C. Tenover, R.H. Yolken (Eds.), Manual of Clinical Microbiology, 7th ed., American Society for Microbiology, Washington DC, 1999, pp. 297 – 315. [6] National Committee for Clinical Laboratory Standard. Methods for dilution antimicrobial susceptibility tests for bacteria that grow aerobically Approved Standard. 5th ed. Wayne (PA): NCCLS 2000.Document M7-A5, 27. [7] V. Pintada, et al., Enterococcal meningitis: a clinical study of 39 cases and r review of the literature, Medicine (Baltimore) 82 (2003) 346 – 364.