Letters to the Editor / International Journal of Antimicrobial Agents 34 (2009) 490–503 499 [4] Leonard SN, Rybak MJ. Evaluation of vancomycin and daptomycin against methicillin-resistant Staphylococcus aureus and heterogeneously vancomycin- intermediate S. aureus in an in vitro pharmacokinetic/pharmacodynamic model with simulated endocardial vegetations. J Antimicrob Chemother 2009;63:155–60. [5] Clinical and Laboratory Standards Institute. Methods for dilution antimicrobial susceptibility tests for bacteria that grow aerobically; approved standard. 7th ed. Document M07-A7. Wayne, PA: CLSI; 2006. [6] Clinical and Laboratory Standards Institute. Performance standards for antimi- crobial susceptibility testing. Nineteenth informational supplement. Document M100-S19. Wayne, PA: CLSI; 2009. [7] Biedenbach DJ, Bell JM, Sader HS, Fritsche TR, Jones RN, Turnidge JD. Antimicro- bial susceptibility of Gram-positive bacterial isolates from the Asia-Pacific region and an in vitro evaluation of the bactericidal activity of daptomycin, vancomycin, and teicoplanin: a SENTRY Program Report (2003–2004). Int J Antimicrob Agents 2007;30:143–9. Dilip Mathai a Douglas J. Biedenbach b,∗ Ronald N. Jones b Jan M. Bell c John Turnidge c,d Helio S. Sader b , India Daptomycin Study Group 1 a Christian Medical College, Vellore, India b JMI Laboratories, 345 Beaver Kreek Centre, Suite A, North Liberty, IA 52317, USA c Women’s and Children’s Hospital, Adelaide, Australia d University of Adelaide, Adelaide, Australia ∗ Corresponding author. Tel.: +1 319 665 3370; fax: +1 319 655 3371. E-mail address: douglas-biedenbach@jmilabs.com (D.J. Biedenbach) 1 The India Daptomycin Study Group is composed of: Dr Anil Kumar and Kavitha Radhakrishnan Dinesh (Amrita Institute of Medical Sciences and Research Center, Kochi, Kerala); Ratna Rao (Apollo Hospital, Hyderabad, Andhra Pradesh); Dr Chitnis (Choithram Hospital and Research Center, Indore, Madhya Pradesh); Dr Mohana (Dr Somervell Memorial CSI Mission Hospital,Trivandrum, Kerala); D.K. Mendiratta and Vijayashri Deotale (Kasturba Hospital, Sevagram, Maharashtra); Suganthi Rao (Kasturba Medical College, Manipal, Karnataka); Anuradha Manoj (Kothari Hospital, Kolkata, West Bengal); Molly Madan (Pandit Deen Dayal Upadhyaya Medical College, Rajkot, Gujarat); Camilla Rodriguez and Ajitha Mehta (P.D. Hinduja Hospital, Mumbai); Shankar Sengupta (Ruby Hospital Institute of Child Health, Kolkata, West Bengal); Manorama Deb and Deepthi Nair (Safdarjung Hospital, New Delhi); Preeti Mehta (SG Seth & KEM Hospital, Mumbai, Maharashtra); Chand Wattal (Sir Ganga Ram Hospital, New Delhi); Padma Srikanth (Sri Ramachandra Medical College, Chennai); Dr Vaidehi and Dr Ram Rajagopalan (Sundaram Medical Foundation, Chennai); Rohini Kelkhar (Tata Cancer Center, Mumbai); and Dr Anand Manoharan (Christian Medical College, Vellore). doi:10.1016/j.ijantimicag.2009.06.008 In vitro antibiotic susceptibility of Vibrio parahaemolyticus from environmental sources in northern England Keywords: Vibrio parahaemolyticus Environmental Antibiotic resistance Sir, Vibrio parahaemolyticus is a Gram-negative, halophilic bac- terium found in estuarine environments worldwide that can be isolated from seawater, sediments, fish (including shellfish) and zooplankton. Gastrointestinal infections are frequently associated with consumption of raw or improperly cooked and contami- nated shellfish; less commonly, severe wound infections may occur after exposure of open wounds to contaminated seafood and/or seawater. Antimicrobial agents are used in the treatment and control of prolonged and severe V. parahaemolyticus infection, espe- cially when it occurs in infants, the elderly or immunosuppressed patients. The majority of susceptibility patterns from different geo- graphical regions have previously focused on tropical/subtropical areas in Asia, America and parts of southern Europe, however the present study reports from Northern Europe. The study location is Cleethorpes, Lincolnshire, UK, a recreational resort situated along the River Humber estuary that receives a large number of visi- tors over the summer months, with several shellfish harvesting activities and mussel cultivation along the coastal line. This study sought to update the antimicrobial resistance status of recent envi- ronmental V. parahaemolyticus isolates from this area. Samples of mussels, water and sediment were collected from a single location between September 2007 and September 2008 and were subjected to antibiotic susceptibility testing. Homogenised samples contain- ing 25 g of sediment or mussels or 25 mL of seawater in 225 mL of alkaline peptone water (pH 8.6) with the addition of 2% sodium chloride were incubated at 37 ◦ C and a portion of each enriched sample was plated out onto chromogenic Vibrio agar (CHROMagar, Paris, France). Purple colonies were subcultured and confirmed by API20E and polymerase chain reaction (PCR) amplification of the V. parahaemolyticus-specific target tlh gene [1]. Antibiotic sensitivity testing was performed by the Bauer–Kirby disk diffusion method with zone diameter interpretation as recommended by the Clinical and Laboratory Standards Institute (CLSI) [2]. The multiple antibi- otic resistance (MAR) index of isolates was defined as x/y, where x represents the number of antibiotics to which a particular isolate was resistant and y represents the number of antibiotics to which the isolate was exposed. A total of 76 isolates of V. parahaemolyticus was recovered from mussels, seawater and sea sediment. Antibiotic susceptibilities according to disk diffusion zone diameters are shown in Table 1. In terms of percentage resistance, isolates were most resistant to kanamycin (87.8%), gentamicin (73.7%), cefazolin (48.7%) and tetra- cycline (20.0%), but less resistant to ampicillin (1.3%), ciprofloxacin (9.2%) and vancomycin (3.9%). In addition, 10.5% (8/76) of all the iso- lates tested remained susceptible to all antimicrobials, 10.5% (8/76) exhibited resistance to one antimicrobial and the remainder (78.9%; 60/76) demonstrated resistance to two or more agents. The antibi- otic resistance patterns of coastal isolates from water, sediment or mussels did not differ greatly, although direct comparison of mussel and water isolates demonstrated reduced susceptibility to cefazolin and tetracycline, respectively. The only ampicillin-resistant isolate of V. parahaemolyticus in this study was obtained from a water sam- ple. Among the 11 different resistance profiles observed, resistance to gentamicin and kanamycin occurred most frequently (Table 2). Disease outbreaks associated with marine organisms appear to be escalating worldwide and a growing number of human bacterial infections have been associated with recreational and commercial use of marine resources. The prevalence of antimicrobial resis- tance among food-borne pathogens has increased during recent decades and in Vibrio spp. it has been observed to be dynamic and varies with the environment [3]. In China, Vibrio spp. (including V. parahaemolyticus) isolated from Sparus sarba have shown resis- tance to ampicillin (60.8%) and kanamycin (58.8%) [4]. A similar study conducted in Indonesia from 1995 to 2001 revealed that V. parahaemolyticus isolates began to show an unusual resistance to ciprofloxacin (11%), and the same study also recorded 100% resis- tance to ampicillin, 9% to tetracycline and 15% to chloramphenicol [5]. Another study carried out in Bangladesh revealed that V. para-