Two cases of Vancomycin-resistant enterococci from Singapore

Letters to the Editor combination of ceftazidime and ciprofloxacin was additive. 2 In our patient, the use of ciprofloxacin did not prevent the failure of treatment with ceftazidime.

Acknowledgements We express our thanks to Dr T.L. Pitt and Dr D. A. B. Dance for their help. R. K. Patel I, M. D. Smith 2, D. R i m m e r 1, M. A. Hanid ~

~Department of Gastroenterology and Microbiology, Hillingdon Hospital, Pield Heath Road, Uxbridge, Middlesex UB8 3NN, U.K. and 2Public Health Laboratory, Musgrove Park Hospital, Taunton, Somerset TA1 5DB, U.K.

References 1 Dance DAB, Wuthiekanum V, Chaowagul W, White NJ. The antimicrobial susceptibility of Pseudomonas pseudomallei. Emergence of resistance in vitro and during treatment. ] Antimicrob Chemother 1989; 24: 295-309. 2 Smith MD. Wuthiekanun V, Walsh AL, White NJ. Susceptibility of Pseudomonas pseudomallei to some newer [3-1actam antibiotics and antibiotic combinations using time-kill studies, l Antimicrob Chemother 1994; 33:145 149. 3 Lumbiganon R Saengsa-Ard S, Wilailuckana C. Imipenem therapy for melioidosis in two children. PediatrInfect Dis J 1992; 11: 414-416. 4 Wilks D, Jacobson SK, Lever AML, Farrington M. Fatal melioidosis in a tourist returning from Thailand. ] Infect 1994; 29: 87-90.

Accepted for publication 11 April 1997

Two Cases of Vancomycin-resistant Enterococci from Singapore Sir Enterococci are important pathogens largely because of their antimicrobial resitances.l Vancomycin resistance is undoubtedly the greatest concern, 2 and m a n y reports about vancomycinresistant enterococci (VRE) are available from the West. VRE are often attributed to nosocomial acquisition and are associated with severe underlying disease, immunosuppression, indwelling urinary or central venous catheters, prolonged hospitalization and administration of multiple antibiotics (especially vancomycin and cephalosporins)? To date, there is no report of VRE from Asia. This paper describes the characteristics of two cases of VRE from a Singapore hospital. The isolates were obtained from urinary specimens of two patients managed in a Singapore hospital with 1000 beds. Case A is a 49-year-old Chinese male seen on 9 October 1995 at the outpatient clinic with complaints of backache and urinary disturbance. Clinical examination was unremarkable. Urine microscopy was normal, but urine culture yielded Enterococcus faecalis with viable count of 5 x 104 CFU/ml. He was treated symptomatically for his backache and was well w h e n last seen at the outpatient clinic. Case B is a 55-year-old Chinese female admitted on 1 l u n e 1995 with acute retention of urine which was due to bilateral hydronephrosis. The patient had a significant past history of cervical carcinoma diagnosed in 1974

133

and had hysterectomy followed by irradiation. Multiple instrumentation was carried out to determine the sites of obstruction as well as palliative measures to relieve the obstruction: antegrade pyelogram 6 June 1995, stent insertion 7 June 1995, cytoscopy and bilateral urethroscopy 8 June 1995 and nephrostogram 14 June 1995. On 9 June 1995 urine culture grew Klebsiella pneumoniae and E. faecalis. Speciation of enterococc{ was carried out with API 20 Strep method (Bio Merieux SA, France). Initial vancomycin resistance was detected by 30 ~tg disks using the Kirby-Bauer method. 4 Minimum inhibition concentrations (M[Cs) for vancomycin and teicoplanin were carried out using NCCLS agar dilution method. ~ Ampicillin MIC was read by E test (AB Biodisk, Sweden). High level aminoglycoside resistances were determined by disks incorporating gentamicin 120 ~tg, streptomycin 300 ~tg or kanamycin 120 gg. Both A and B strains were phenotypically vanB 6 with vancomycin MICs 2 5 6 m g / 1 (A) and 128mg/1 (B). MICs were identical against teicoplanin (1 mg/l) and ampicillin (0.25 mg/ 1). Both strains were susceptible to gentamicin; strain A showed high-level aminoglycoside resistances to streptomycin .and kanamycin and strain B to streptomycin. VRE from Case A was community-acquired and Case B hospital-acquired. Case B had ceftazidime prior to the urine culture whilst Case A had none. The VRE bacteriurias were transient and resolved without antimicrobial intervention. A check with the relevant authorities in Singapore did not implicate avoparcin as a possible reason for the emergence of vancomycin resistance in enterococci, as it was not used in veterinary medicine and animal feed in this region. An unpublished study completed recently in another Singapore hospital revealed faecal carriage of VIlE of more than 10% in inpatients. 7 VRE has emerged in Asia and quick action is needed to prevent it becoming an endemic problem in this area. It is necessary that microbiologists in Asia begin to review existing recommendations in order to detect, prevent and control VRE. Y.-F. Chiew ~ and M-L. Ling 2

~Department of Laboratory Medicine, National University Hospital, 5 Lower Kent Ridge Road, 119704, Singapore, 2Department of Pathology, Singapore General Hospital, Outram Road, 169608, Singapore

References 1 Moellering RC Jr. Emergence of Enterococcus: a significant pathogen. Clin Infect Dis 1992; 14: 1173-3178. 2 Centers for Disease Control and Prevention. Nosocomial enterococci resistant to vancomycin-United States, 1989-1993. MMWR 1993; 42:597-599. 3 Low DE, Willey BM, McGeer AJ. Multidrug-resistant enterococci; a threat to the surgical patient. Am l Surg 1995; 169(5A Suppl): 8S-12S. 4 Bauer AW. Kirby WMM, Sherris JC et al. Antibiotic susceptibility testing by a standardized single disk method. Am ] Clin Pathol 1996; 45: 493-496. 5 Methods for dilution antimicrobial susceptibiIity tests for bacteria that grow aerobically-third edition. NCCLS 1993; MT-A3 13(25). 6 Arthur M, Courvalin P. Genetics and mechanisms of glycopeptide resistance in enterococci. Antimicrob Agents Chemother 1993; 37: 1563-1571. 7 0 o n LLE, Chiew YF. Stool carriage of vancomycin-resistant enterococci in a Singapore teaching hospital. Proceedings and abstracts

134

Letters to t h e Editor

of the Joint Scientific Meeting of Royal College of Pathologists of Australasia; Singapore Society of Pathology and Malaysian Society of Pathologists, 1997, October 6-9, Singapore.

or cat bites even w h e n lesions are superficial, not only in immunocompromised patients, but also in previously healthy persons. P. Blanche, 12 E. Bloch, 2 D. S i c a r d 2 ~Service of Internal Medicine (Dr. G. Harrman), Fondation Hdpital Saintqoseph, 185 rue Raymond Lorrerand, 75674 Paris, Cedex 14, France and 2Service of Internal Medicine (Pt: D. Sicard), H6pital Cochin, 27 rue du Faubourg Saint-]acques, 75679 Paris, Cedex 14, France

Accepted for publication 18 April 1997

Capnocytophaga canimorsus in the Oral Flora of Dogs and Cats Sir, Capnocytophaga canimorsus, previously called dysgonic fermenter type 2 (DF-2), is an oral commensal of animals. It is implicated in a large spectrum of disorders, mostly septicaemia, following dog bites and other close contact with dogs and, occasionally, cats. One hundred and twenty-six cases of C. canimorsus septicaemia have been reported in the English-language literature.I The incidence of this condition has been estimated to be 0.5 cases per 1 million people per year in a recent publication by C. Pers et al. in Denmark. a In 1993 we observed a 57-year-old m a n who developed C. canimorsus septicaemia and meningitis 9 days after a bite on a finger by a poodle. Specimens from the dog's m o u t h yielded C. canimorsus. 2 Consequently we investigated the oral flora of 90 dogs, 120 cats, 35 hamsters and 100 h u m a n beings, between February and October 1995, in the military camp of Cambrai, Northern France. Cotton wool-tipped swabs of superior and inferior gingival margins were placed in charcoal based transport medium for delivery to the laboratory, where they were cultured on aerobic (Bactec 6B) and anaerobic (Bactec 7D) medium. Plates were incubated in 95% air and 5% CO2 in 95% relative humidity at 37°C and examined after 7 days. The bacteria were identified according to the methods of Weaver et al. 3 Altogether, 345 swabs were collected. Table I shows the results. Two studies have been made to determine the frequency of carriage of C canimorsus in animals. Bailie et al. found the organism in the oral and nasal fluids of four out of 50 dogs (8%).4 Westwell et al. isolated C canimorsus in a higher proportion of dogs (44 out of 180 dogs (24%)) and in 42 out of 249 cats (17%), three out of 12 sheep (25%) and five out of 15 cattle (33%). s Our isolation rate is the same as that described by Westwell. The organisms are easily recovered from dogs, and also cats. There has been only one report of infection after a cat bite, but three out of five reported eye infections have been observed after corneal cat scratch injuries. 6 Our findings support the view that domestic pets are the source of infection in humans. As penicillin seems to be the drug of choice for C. canimorsus infections, prophylactic penicillin should be considered for every patient after dog or cat bites. 7 Attention should be drawn to the possibility of C. canimorsus septicaemia developing after dog

~able I. Isolation of C. canimorsus from oral swabs.

Dogs Cats Hamsters Humans

Total

C. canimorsus isolated (%)

90 120 35 100

23 (25.5) 18 (15) 0 0

References 1 Pers C, Gahrn-Hansen B, Frederiksen W. Capnocytophaga canimorsus septicemia in Demnark, 1982-1995: review of 39 cases. Clin Infect Dis 1996; 23: 71-75. 2 Blanche P, Sicard D, Meyniard O, Ratovohery D, Brun T, Paul G. Capnocytophaga canimorsus lymphocytic meningitis in an immunocompetent man who was bitten by a dog. Clin Infect Dis 1994; 18: 654-655. 3 Weaver RE, Hollis DG, Bottone EJ. Gram-negative fermentative bacteria and Francisella tularensis. In: Lennette EH, Balows A, Hausler WJ Jr, Shadomy HJ, eds. Manual of clinical microbiology, 4th ed. Washington, DC: American Society for Microbiology, 1985:309 329. 4 Bailie WE, Stowe EC, Schmitt AM. Aerobic bacterial flora of oral and nasal fluids of canines with reference to bacteria associated with bites. J Clin Microbiol 1978; 7: 223-231. 5 Westwell AJ, Kerr K, Spencer MB, Hutchinson D. DF-2 infection. BM] 1989; 298: 116-117. 6 Carpenter PD, Heppner BT, Gnann JW. DF-2 bacteremia following cat bites-report of two cases. Am J Med 1987; 82: 621-623. 7 Goldstein EJC. Bite wounds and infection. Clin Infect Dis 1992; 14: 633-640. Accepted for publication 13 May 1997

Disseminated Rhodococcus equi and Nocardia farcinica Infection in a Patient with Sarcoidosis Sir, Disseminated infection by combinations of opportunistic agents is being increasingly reported in immunocompromised patients. We report the first case of a mixed systemic infection caused by Rhodococcus equi and Nocardia farcinica in a patient receiving corticosteroid therapy for sarcoidosis. A 49-year-old, HIV-negative m a n receiving prednisone therapy (20 mg per day) for pulmonary sarcoidosis was admitted to our intensive care unit postoperatively after a decompressive laminectomy. His recent history included pneumonia 5 months previously due to R. equi sensitive to imipenem, rifampicin, cotrimoxazole, erythromycin, ofloxacin and vancomycin. Therapy with erythromycin (3 g per day) and ofloxacin (400 mg per day) for 2 months was successful. After operation the patient's temperature was 38.5 °C and the blood leucocyte was 20 0 0 0 / m m 3. Clinical examination and the initial chest X-ray showed bilateral consolidation and pleural effusions. The patient was intubated for hypoxemic respiratory failure, and specimens of urine, blood, and bronchial secretions were sent for culture. By day 3 all cultures were negative and therefore no antimicrobial therapy was given. His condition continued to worsen