Case Report

Emergence of pristinamycin resistance in India Shyam Sunder Keshari, Arun Kumar Kapoor, Nira Kastury, Dharmendra Kumar Singh2, Anudita Bhargava1

ABSTRACT 1Department of Pharmacology and Microbiology, Moti Lal Nehru Quinupristin and combination has been advocated as a drug of choice for Medical College, Allahabad, Uttar multi-drug resistant (MDR) gram-positive cocci (GPC). We are reporting two cases of 2 Pradesh, Department of Pediatrics, neonatal septicemia, caused by the methicillin resistant Staphylococcus aureus (MRSA), Sarojini Naidu Children Hospital, showing primary in vitro pristinamycin resistance. The Minimum inhibitory concentrations Allahabad, Uttar Pradesh, India (MIC) for pristinamycin in these two cases were 30 µg and 25 µg, respectively. Universal RReceived:eceived: 23.06.2007 advocacy of pristinamycin for the therapy of MDR GPC infections should be re-evaluated. RRevised:evised: 06.08.2008 AAccepted:ccepted: 08.02.2009

DDOI:OI: 10.4103/0253-7613.48884 CCorrespondenceorrespondence to:to: Dr. Arun Kumar Kapoor E-mail: [email protected] KKEYEY WWORDS:ORDS: Dalfopristin/quinupristin, pristinamycin resistance, staphylococcus

Introduction Staphylococcus aureus, which were resistant to pristinamycin (quinupristin/dalfopristin). Quinupristin and dalfopristin (SYNECID) is a combination of a B, quinupristin, with a streptogramin Case Reports A, dalfopristin, in a 30 : 70 ratio. These compounds are semisynthetic derivatives of naturally occurring pristinamycins, Case 1 produced by pristinaspiralis. Quinupristin and A 17-day-old male baby was brought to the out-patient dalfopristin are more soluble derivatives of pristinamycin ΙA and section of the pediatrics department, with a history of refusal to pristinamycin ΙΙA respectively.[1] They bind with different targets feed, sluggish activity and yellow discoloration of the body. There in the peptidyltransferase domain of 23 ribosomal subunit, and was no history of Rh-incompatibility. On physical examination, inhibit protein elongation steps. Streptogramin A and B act the neonate appeared ill and was icteric. His laboratory synergistically in vivo; the mixture of the two components is investigations were serum bilirubin - 17.6 mg%, serum calcium bactericidal and the action is irreversible unlike their individual - 8.2 mg%, blood sugar (Random) - 72 mg%, haemoglobin-16.8 bacteriostatic activity.[2] gm%, TLC - 5,800/cmm and DLC was polymorphs 82% and The first staphylococcal isolate resistant to the lymphocyte 18%. Blood culture was positive for MRSA. He was pristinamycin was reported in France, in 1975.[3] treated as a case of septicemia with Icterus neonatorum, in the Staphylococcal resistance always pertains to dalfopristin, neonatal intensive care unit (NICU). but not necessarily for quinupristin.[4] Quinupristin resistance Case 2 to Staphylococci is mediated by various mechanisms A 5-day-old preterm female baby was brought to the out- like methylation of 23s rRNA,[5] inactivation of drug by patients section of the pediatric department with a history lactonases,[1] mutation in the L22 ribosomal protein[6] and by of refusal to feed, sluggish activity, yellow discoloration of efflux of the drug by ABC proteins.[7,8] Similarly, resistance the body, respiratory distress and seizure. There was no to dalfopristin is mediated by plasmid genes like vat, vatB, history of Rh-incompati-bility. On physical examination, the vatC, vatD and satA;[4] staphylococcal genes vga, vgb, vgaB neonate appeared ill and icteric, with hypothermia, weak cry, and lsa, which encode ATP-binding efflux proteins that pump tachycardia, tachypnea and poor motor activity. Her laboratory type A compounds out of the bacterial cell.[4,8] A variant of investigations were blood sugar (Random) - 112 mg%, serum vgaA (vgaAv) carried by a transposon (Tn5406) found in bilirubin - 11.3 mg%, and serum calcium-3.9 mg%. Blood culture plasmid and/or chromosome of staphylococci was recently was positive for MRSA. She was treated in the NICU as a case characterized.[9] We have isolated two clinical isolates of of birth asphyxia with septicemia with Icterus neonatorum.

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Blood culture and sensitivity was done as per standard other commonly used . Probably this gene was in a protocol, in the Department of Microbiology, M.L.N. Medical repressed state and was expressed on first exposure to the College, Allahabad. The samples were collected in Brain heart drug. Various genes have been identified which are responsible infusion broth and periodically sub-cultured on MacConkey agar for causing streptogramin resistance, like erm, vgb A, vgb B, and blood agar. The colonies that grew were identified to the and msr genes. species level by a battery of biochemical tests. These isolates More clinical isolates need to be tested against this , were tested by Kirby-Bauer disc diffusion method, against so that the exact percentage of primary in vitro resistance can a panel of relevant antibiotics, using commercially available be known. Genetic studies for the responsible gene(s) should antibiotic discs.[10] The antibiotics tested included ampicillin, be done. After the above two cases, we are now storing all amoxycillin-clavulanic acid, , cephalexin, cephazolin, the pristinamycin resistant GPC isolates in our laboratory for co-trimoxazole, , ciprofloxacin, , further studies. We have isolated other pristinamycin resistant gentamycin, , oxacillin, pristinamycin (dalfopristin/ GPCs also, from specimens other than blood. After complete quinupristin), , teicoplanin and vancomycin. The comprehensive studies on all such isolates have been done to MIC of pristinamycin was determined by E-test strips (Hicomb find out the exact percentage of primary in-vitro resistance strips from Hi Media Laboratories, Pvt. Ltd., India). against this drug, in this part of our country. Thus, on the basis Result and Discussion of our observation, it is advisable that more comprehensive region-wise laboratory work is done, before advocating this The blood samples of both the cases showed growth of drug for empirical therapy for MDR GPC infections. MRSA. The MRSA was also resistant to pristinamycin by initial screening, using the Kirby Bauer disk diffusion method. The References MICs for dalfopristin/quinupristin among these two isolates 1. Chamber HF. Antimicrobial agents: Protein synthesis inhibitors and miscellaneous were 30 µg ml-¹ and 25 µg ml-¹. Although this test is not antibacterial agents. In: Burton LL, Lazo JS, Parker KL, editors. Goodman and approved by the NCCLS, there are numerous studies which Gillman’s the pharmacological basis of therapeutics. 11th ed. New York: McGraw- showed that E-test disk diffusion and broth micro dilution Hill; 2006. p. 1173-202. methods were comparable in accuracy for the susceptibility 2. Haroche J, Morvan A, Davi M, Allignet J, Bimet F, El Solh N. Clonal diversity among streptogramin A: resistant Staphylococcus aureus isolates collected in testing for MRSA and vancomycin resistant Enterococcus (VRE) French hospitals. J Clin Microbiol 2003;41:586-91. [11] against linezolid and quinupristin/dalfopristin. 3. El Solh N, Allignet J. Staphylococcal resistance to and related

Earlier studies have shown very low MIC; MIC90 of 1-2 antibiotics. Drug Resist Updates 1998;1:169-75. mg l-¹ for MRSA and 0.5 -2 mg l-¹ for CONS, Streptococcus 4. Allignet J, Aubert S, Morvan A, El Solh N. Distribution of genes encoding resistance pneumoniae, Streptococcus viridans and Streptococcus to streptogramin A and related compounds among staphylococcal resistant to pyogenes. Earlier studies have reported that almost all these antibiotics. Antimicrob Agents Chemother 1996;40:2523-8. 5. Weisblum B. Resistance to the –lincosamide –streptogramin antibiotics. isolates of MRSA and MRCONS are susceptible to dalfopristin/ In: Fischetti VA, et al, editors. Gram-positive pathogens. Washington, DC: ASM [11,12] quinupristin. However, our findings were in contrast to Press; 2000. p. 694-710. the earlier studies done in this field. 6. Malburny B, Canu A, Bozdogan B, Fantin B, Zarrouk V, Dutka-Malen S, et al. Infections due to gram-positive cocci are becoming Resistance to quinupristin-dalfopristin due to mutation of L22 ribosomal protein more difficult to treat because of rapid emergence of in Staphylococcus aureus. Antimicrob Agents Chemother 2002;46:2200-7. antibiotic resistance and their dissemination in the 7. Ross JI, Farrell AM, Eady EA, Cove JH, Cunliffe WJ. Characterisation and molecular cloning of the noval macrolide–streptogramin B resistance determinants population. Earlier observations have demonstrated that from Staphylococcus epidermidis. J Antimicrob Chemother 1989;24:851-62. dalfopristin/quinupristin have good activity against MDR 8. Singh KV, Malathum K, Murray BE. Disruption of an Enterococcus faecium gram-positive cocci and are a promising therapeutic option species-speciÞ c gene: A homologue of acquired macrolide resistance genes in the era of rapidly increasing resistance in almost all of staphylococci, is associated with an increase in macrolide susceptibility. parts of the world. Antimicrob Agents Chemother 2001;45:263-6. It is very interesting to find pristinamycin resistant 9. Haroche J, Allignet J, El Solh N Tn 5406, a new staphylococcal transposon conferring resistance to streptogramin A and related compounds, including Staphylococcus aureus in our country, where pristinamycin is dalfopristin. Antimicrob Agents Chemother 2002;46:2337-43. not available in vivo for patient management. Pristinamycin is 10. National Committee for Clinical Laboratory Standards. Performance standards for being used only as a research tool, by using antibiotic discs antimicrobial susceptibility testing. Twelfth informational supplement. M100-S12 procured from a commercial source. NCCLS, 2002. Wayne P.A. In the present study, the Staphylococcal isolates were 11. Abb J. In vitro activity of linezolid, quinupristin-dalfopristin, vancomycin, teicoplanin, found resistant to three or more antimicrobial agents among moxiß oxacin and mupirocin against methicillin resistant Staphylococcus aureus: the panel of antibiotics tested. Therefore, they were defined Comparative evaluation by the E test and broth micro dilution method. Diagn Microbiol Infect Dis 2002;43:319-21. as MDR Staphylococcal isolates. It may be postulated that 12. Eiff C, Peters G. Comparative in- vitro activities of moxiß oxacin, trovaß oxacin, resistance against pristinamycin is plasmid mediated. This quinupristin/dalfopristin and linezolid against staphylococci. J Antimicrob plasmid may also contain genes conferring resistance against Chemother 1999;43:569-73.

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