- Email: [email protected]
P98 Antimicrobial susceptibility of Citrobacter koseri isolated from clinical specimen in western part of Japan
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Posters / International Journal of Antimicrobial Agents 42S2 (2013) S41–S159
P94 Antimicrobial susceptibility of various antibiotics against Neisseria gonorrhoeae isolates in western part of Japan T. Kobayashi1 *, T. Muratani1 , T. Matsumoto2 . 1 Department of Clinical Microbiology, Kyurin medical laboratory, 2 Urology, University of Occupational and Environmental Health, Kitakyushu, Japan E-mail address : [email protected] Introduction: We have reported that the N. gonorrhoeae isolates from clinical failure cases treated with oral 3rd generation cephems including 400 mg cefixime in Japan. These isolates had PBP-2 alteration. We have also reported against these resistant isolates the MIC of cefozopran showed more than 2 mcg/ml. Objectives: To research the prevalence of these cefozopran resistant isolates, we examined the susceptibility of N. gonorrhoeae isolates to various antimicrobial agents. Methods: During January 2009 to September 2012, 345 N. gonorrhoeae isolates from individual patients in western part of Japan were used. The MICs of various antimicrobials were determined by agar dilution method. Results: 254 of 345 patients (73.6%) were male. Ceftriaxone and cefodizime inhibited growth of all isolates at 0.25 and 0.5 mcg/ml, respectively. The MIC range of spectinomycin was 2 to 32 mg/L. These 3 agents had no resistant isolates. Penicillin susceptibile (MIC 0.06 mcg/ml) and high resistant (MIC 1 mcg/ml) isolates were 7.8 and 44.1%, respectively. Penicillinase producing isolate was only 2 isolate (0.6%). Cefozopran resistant isolates (MIC 2 mcg/ml) were 49.3% (170/345). Levofloxacin, tetracycline, and erythromycin susceptible isolates (MIC 0.25 mcg/ml) were 31.6, 31.0, and 13.6%, and high resistant isolates ( 2 mcg/ml) accounted for 64.1, 27.2, and 20.0%, respectively. The result showed that most of cefozopran resistant isolates was multi-drug resistant. Conclusion: Cefozopran resistant isolates accounted for about half. And the susceptibility ratio of the non-beta-lactam oral agents was less than 35%. Therefore in Japan, no effective oral agents exist against gonococcal infections. It is a serious problem in Japan. Only three parenteral agents, ceftriaxone, cefodizime, and spectinomycin, are recommended for gonococcal infection in Japan. P95 Withdrawn
P96 Clinically significant drug interactions among HIV-infected patients receiving antiretroviral therapy in outpatient HIV clinic A. So-Ngern1 , W. Manosuthi2 *. 1 Faculty of Pharmacy Siam university, Bangkok, 2 Medicine, Bamrasnaradura Infectious Diseases Institute, Ministry of Public Health, Nonthaburi, Thailand E-mail address : [email protected] Introduction: Drug-drug interactions have become an increasingly complex challenge for physician treating HIV-infected patients. Objectives: To study the prevalence, patterns, and risk factors for clinically significant drug-drug interactions (CSDIs) in the prescription of HIV-infected patients receiving antiretroviral therapy (ART). Methods: A cross sectional study was conducted to review outpatient medical records of 1,000 HIV-infected patients who were attending and receiving ART in 2011. The severities of CSDIs were graded according to the Micromedex® 2.0 database and the 2012 DHHS HIV treatment guideline. Results: Of all patients, 333 (33%) had 554 CSDIs. Of 554 CSDIs, the prevalence of grade 2, 3, and 4 CSDIs were 61% (n = 337), 29% (n = 163), 10% (n = 54), respectively. Based on ART regimens, CSDIs were identified in protease inhibitor (PI)-based (79%), efavirenz-based (34%) and nevirapine-based regimens (10%) (P < 0.001). The three most frequent grade 4 CSDIs included PIs vs. simvastatin (n = 24), simvastatin vs. gemfibrozil (n = 24), and didanosine vs. allopurinol (n = 2). The three most frequent grade 3 CSDIs included PIs vs. statin drugs except simvastatin (n = 56), fenofibrate vs. statin drugs (n = 28), and amlodipine vs simvastatin (n = 14). In the multivariate analysis, risk factors associated with CSDIs were receiving PIs-based regimen
(OR = 13.9; 95% CI = 8.8–22.0), having dyslipidemia (OR = 3.8; 95% CI = 1.8–8.0), duration of ART > 5 years (OR = 2.2; 95% CI = 1.3–3.6), CD4 count > 200 cells/mm3 (OR = 2.1; 95% CI = 1.2–3.9), number of item > 5 per prescriptions (OR = 1.8; 95% CI = 1.2–2.7), and number of visits > 4 times a year (OR = 1.6; 95% CI = 1.1–2.3). Conclusion: CSDIs are highly prevalent among HIV-infected patients receiving ARV in the outpatient clinic. Patients with receiving PIbased ART, long duration of ART, low CD4 count, having dyslipidemia, having frequent number of visit a year and high number of item per prescription had a higher chance of occurring CSDIs. P97 Antimicrobial susceptibility of viridans group streptococci in Japan during 2009 and 2012 M. Minami1 *, M. Kuriyama1 , Y. Oshima1 , H. Nishiyama2 , S. Ikegami2 , M. Kawashima3 , M. Ohta4 . 1 Bacteriology, Nagoya City University, 2 Clinical Laboratory, Nagoya First Red Cross Hospital, 3 Clinical Laboratory, Nagoya Second Red Cross Hospital, 4 Nursing, Sugiyama Jogakuen University, Nagoya, Japan E-mail address : [email protected] Introduction: The viridans group streptococci make up a heterogeneous group of streptococci that inhabit the mouth, gastrointestinal tract and female genital tract and they are also the leading cause of invasive diseases such as subacute bacterial endocarditis, catheter- and neutropenia-related bloodstream infections. Objectives: The objective of this study was to determine the incidence and patterns of antimicrobial resistance among viridans group streptococci isolated in Japan. Methods: We determined the in-vitro susceptibilities of 11 antimicrobial agents (ABPC, PCG, SBT/ABPC, CTX, CFPM, MEPM, VCM, EM, CAM, LVFX, and ST) for 146 isolates of viridans group streptococci recovered from patients with invasive infections at Nagoya First Red Cross Hospital and Nagoya Second Red Cross Hospital in Japan during 2009 and 2012. Results: Variable degrees of susceptibility existed among 12 viridans group streptococcus species (Streptococcus acidominimus , Streptococcus anginosus , Streptococcus bovis , Streptococcus constellatus , Streptococcus gordonii , Streptococcus intermedius , Streptococcus mitis , Streptococccus mutans , Streptococcus oralis , Streptococcus parasanguinis , Streptococcus salivarius , and Streptococcus sanguinis ). In all, 15.1% of the isolates were non-susceptible to ABPC. Nine of 22 ampicillin non-susceptible isolates had high-level ABPC resistance (Streptococcus mitis 7, Streptococcus sanguinis 2). Rates of non-susceptibility to EM was 40.4% and EM resistance occurred most frequently in Streptococcus bovis isolates (100%), followed by Streptococcus oralis (62.5%), Streptococcus mitis (50%), and Streptococcus acidominimus (50%) but in none of Streptococcus gordonii . Although MEPM was the most active beta-lactam against penicillin-resistant isolates, 14.6% of Streptococcus mitis were non-susceptible to MEPM. Only one Streptococcus anginosus isolate had high-level resistance of VCM. Rates of non-susceptibility to LVFX was 12.3%, and high-level LVFX resistance was found in Streptococcus oralis (37.5%), and Streptococcus mitis (14.6%), respectively. Conclusion: These results indicate the species-related variability of susceptibility, especially to ABPC, EM and LVFX. The differences in susceptibilities among viridans group streptococci suggest the need for continuing surveillance of antimicrobial resistance. P98 Antimicrobial susceptibility of Citrobacter koseri isolated from clinical specimen in western part of Japan T. Muratani1,2,3 *, T. Kobayashi1 , M. Honda1 , Y. Haga1 , K. Doi1 , C. Nagahara1 , T. Matsumoto3 . 1 Hibiki Research Group for Clinical Microbiology, 2 Department of clinical microbiology, Kyurin medical laboratory, 3 Department of urology, University of Occupational and Environmental Health, Kitakyushu, Japan E-mail address : [email protected] Introduction: Multi-drug resistant Citrobacter koseri isolates have been isolated from various hospitals in western part of Japan, from 1999 onwards.
Posters / International Journal of Antimicrobial Agents 42S2 (2013) S41–S159
Objectives: To clarify the ratio of resistant isolates against various antimicrobials in C. koseri , we performed this study. Methods: We used total of 373 non-duplicate C. koseri isolated from various clinical specimen from 75 hospitals in western part of Japan in the period from 2008 to 2010. The MICs of various antimicrobials against the isolates were determined by the two-fold serial agar dilution method as described by the CLSI. The resistant isolates to antimicrobials were interpreted as showing more than following breakpoint MIC. Antimicrobials (their breakpoint MIC) used in this study as follows; ampicillin (8), piperacillin (8), piperacillin/ tazobactam (8/4), faropenem (2), cefazolin (8), cefotiam (8), cefmetazole (16), flomoxef (8), cefpodoxime (2), cefditoren (2), aztoreonam (8), imipenem (4), meropenem (4), levofloxacin (2), minocycline (4), gentamicin (4), tobramicin (4), amikacin (16), isepamicin (16), trimethoprim/sulfamethoxazole (2/38), and fosfomycin (64). Results: The susceptibility ratios of penicillins, faropenem, cephalosporins except ceftazidime and aztreonam against all 373 C. koseri isolates were less than 50%. The susceptibility ratios of piperacillin/ tazobactam, ceftazidime, cefmetazole, and flomoxef were 52.5, 52.8, 53.1, and 85.3, respectively. Imipenem and meropenem inhibited the growth of all 373 C. koseri isolates at 2 and 4 mcg/ml. The ratios of levofloxacin, minocycline, fosfomycin, and trimethoprim/sulfamethoxazole were 33.8, 39.9, 98.9, and 63.5%. Concerning aminoglycosides, the susceptibility ratios of tobramycin, gentamicin, amikacin, and isepamicin were 76.9, 81.2, 97.9, 98.4%. Six of all 373 isolates showed high aminoglycoside-resistance; the MIC of all aminoglycosides used were more than 128 mcg/ml. Twenty-five of all 373 isolates showed resistance against all antimicrobials except carbapenems, amikacin, tobramycin, and fosfomycin. Conclusion: Most of C. koseri isolates have acquired beta-lactam resistance. The major factors of mechanisms of resistance were plasmid-mediated beta-lactamases, such as CTX-M-2, CTX-M-15, SHV-12, DHA-1, etc. About 7% of all isolates have acquired multi-drug resistance. P99 In vitro antimicrobial property of Rhodomyrtus tomentosa (Ait.) Hassk. against Streptococcus agalactiae isolated from cultured tilapia P. Na-Phatthalung1 *, N. Suanyuk2 , S.P. Voravuthikunchai1 . Department of Microbiology, 2 Department of Aquaculture, Prince of Songkla University, Songkhla, Thailand E-mail address : [email protected]
1
Introduction: Streptocuccus agalactiae is an important fish pathogen in freshwater farms that resulted in a continuous decrease of tilapia production in aquaculture. Ethanol extract of Rhodomyrtus tomentosa leaf and its purified compound, rhodomyrtone has been previously demonstrated to possess a strong antibacterial activity against Grampositive pathogens. Objectives: The purpose of this study was to investigate the in vitro antimicrobial activity of the Rhodomyrtus tomentosa extract on S. agalactiae isolated from tilapia during an outbreak in Southern, Thailand. Methods: Antimicrobial activity of the ethanol extract was performed using broth microdilution method. Time-kill assay was also conducted to evaluate the bactericidal effect of the extract. Scanning electron microscope (SEM) was used to observe morphological changes of bacterial cells after exposure to the extract. In addition, the effect of an oxidative stress on bacterial cells after treatment with the extract was studied using hydrogen peroxide sensitivity assay. Results: Remarkable minimum inhibitory concentrations (MIC) of the Rhodomyrtus tomentosa extract against S. agalactiae (n = 10) were ranged from 31.25 to 62.5 mg/mL. The extract was demonstrated bacteriostatic activity against a representative strain in time-kill studies. Additionally, SEM revealed an irregular shape, different size, and nondividing of S. agalactiae cells after treated with sub-MIC (0.25×MIC) of Rhodomyrtus tomentosa extract. Interestingly, treatment with the extract at sub-MIC (0.125×MIC and 0.25×MIC) significantly increased sensitivity to hydrogen peroxide of exponential phase bacteria. Conclusion: These results suggested that Rhodomyrtus tomentosa is a promising candidate for a new antimicrobial agent against
S73
S. agalactiae which should be further study as an alternative for prevention and control of streptococcal infection in aquaculture. Using an antimicrobial agent base on natural source can reduce the residual levels of antibiotics in fish products and harmful effects to human health. Reference(s) Limsuwana S, et al . (2009) Phytomedicine. 16: 645–651.
P100 Antibiotic susceptiblity pattern of Klebsiella pneumoniae from clinical samples at a tertiary hospital in Ile-Ife, South Western Nigeria A.O. Oladipo1 *, S.J. Udoh1 . 1 Medical Microbiology and Parasitology, Obafemi Awolowo University Teaching Hospitals Complex (OAUTHC), Ile-Ife, Nigeria E-mail address : [email protected] Introduction: In the recent years, klebsiella pneumoniae has become important pathogen in nosocomial infections worldwide. All the isolates of klebsiella pneumoniae identified from January-December 2012 were subjected to antibiotic sensitivity testing on Mueller Hinton agar by modified Kirby–Bauer disc diffusion method using NCCLS guidelines. K. pneumoniae were most frequently isolated from urine 604 (42.5%), sputum 240 (29.9%) followed by blood 180 (42.9%), pus 86 (37.0%) and CSF with the least incidence of 34 (14.8%). All strains were resistant to antibiotics such as amoxycilin 64%, gentamicin 92.6%, erythromycin 82.3%, trimethoprim 88% sulfamethoxazole 96.3%, tetracycline 88.5%, ciprofloxacin 31.2%, nitrofurantoin 31.2%, ceftazidime 69%, cefotaxime 74%, ceftriaxone 79.6% while sensitivity to imipenem was 100% by all the organisms. This study suggested that there is a need for regular antibiotic stewardship and strict surveillance in the hospitals to prevent misuse of available antimicrobials. Keywords: Kebsiella pneumoniae , Gram-negative, noscomial infection Objectives: To determine the antibiotic susceptiblity pattern of k. pneumoniae isolated from samples of patients attending aTertiary Hospitals at Ile-Ife, Nigeria Methods: K. pneumoniae strains were identified by their morphology and biochemical characteristics according to the standards. Antibiotic sensitivity testing was done for all the isolates on Mueller–Hinton agar by modified Kirby–Bauer disc diffusion technique (Bauer, 1990). Results: 1144 clinical samples were cultured from various sites from patients at Obafemi Awolowo University Teaching Hospitals Complex, Ile-Ife. K. pneumoniae were most frequently isolated from urine 604 (42.5%), sputum 240 (29.9%) followed by blood 180 (42.9%), pus 86 (37.0%) and CSF with the least incidence of 34 (14.8%). All isolates were resistant to different antibiotics such as amoxycilin 64%, gentamicin 92.6%, erythromycin 82.3%, trimethoprim, Sulfamethoxazole 96.3% tetracycline 88.5%, ciprofloxacin 31.2% nitrofurantoin 31.2%, ceftazidime 69%, cefotaxime 74%, ceftriaxone 79.6% with all the organisms showing 100% sensitivity to imipenem. Conclusion: All of the strains isolated were sensitive to imipenem. A major increase in resistance and decrease in sensitivity was observed for all the drugs tested towards k. pneumoniae strains isolated from blood, sputum, urine, CSF and pus samples. This study suggested that there is also a need to emphasize on the rational use of antimicrobials and regular antimicrobial susceptibility surveillance is essential.
P101 Aeromonas species isolated from stool cultures and their susceptibilities to various antibiotics B. Ongen1 *, M. Ilktac1 , A. Aydın1 , H. Nazik1 . 1 Medical Microbiology Department, Istanbul University, Istanbul Medical Faculty, Istanbul, Turkey E-mail address : [email protected] Introduction: Aeromonas spp. are emerging agents of gastroenteritis. Since most of the species produce inducible type chromosomal betalactamase, resistance can develop during beta-lactam therapy [1].
Posters / International Journal of Antimicrobial Agents 42S2 (2013) S41–S159
P94 Antimicrobial susceptibility of various antibiotics against Neisseria gonorrhoeae isolates in western part of Japan T. Kobayashi1 *, T. Muratani1 , T. Matsumoto2 . 1 Department of Clinical Microbiology, Kyurin medical laboratory, 2 Urology, University of Occupational and Environmental Health, Kitakyushu, Japan E-mail address : [email protected] Introduction: We have reported that the N. gonorrhoeae isolates from clinical failure cases treated with oral 3rd generation cephems including 400 mg cefixime in Japan. These isolates had PBP-2 alteration. We have also reported against these resistant isolates the MIC of cefozopran showed more than 2 mcg/ml. Objectives: To research the prevalence of these cefozopran resistant isolates, we examined the susceptibility of N. gonorrhoeae isolates to various antimicrobial agents. Methods: During January 2009 to September 2012, 345 N. gonorrhoeae isolates from individual patients in western part of Japan were used. The MICs of various antimicrobials were determined by agar dilution method. Results: 254 of 345 patients (73.6%) were male. Ceftriaxone and cefodizime inhibited growth of all isolates at 0.25 and 0.5 mcg/ml, respectively. The MIC range of spectinomycin was 2 to 32 mg/L. These 3 agents had no resistant isolates. Penicillin susceptibile (MIC 0.06 mcg/ml) and high resistant (MIC 1 mcg/ml) isolates were 7.8 and 44.1%, respectively. Penicillinase producing isolate was only 2 isolate (0.6%). Cefozopran resistant isolates (MIC 2 mcg/ml) were 49.3% (170/345). Levofloxacin, tetracycline, and erythromycin susceptible isolates (MIC 0.25 mcg/ml) were 31.6, 31.0, and 13.6%, and high resistant isolates ( 2 mcg/ml) accounted for 64.1, 27.2, and 20.0%, respectively. The result showed that most of cefozopran resistant isolates was multi-drug resistant. Conclusion: Cefozopran resistant isolates accounted for about half. And the susceptibility ratio of the non-beta-lactam oral agents was less than 35%. Therefore in Japan, no effective oral agents exist against gonococcal infections. It is a serious problem in Japan. Only three parenteral agents, ceftriaxone, cefodizime, and spectinomycin, are recommended for gonococcal infection in Japan. P95 Withdrawn
P96 Clinically significant drug interactions among HIV-infected patients receiving antiretroviral therapy in outpatient HIV clinic A. So-Ngern1 , W. Manosuthi2 *. 1 Faculty of Pharmacy Siam university, Bangkok, 2 Medicine, Bamrasnaradura Infectious Diseases Institute, Ministry of Public Health, Nonthaburi, Thailand E-mail address : [email protected] Introduction: Drug-drug interactions have become an increasingly complex challenge for physician treating HIV-infected patients. Objectives: To study the prevalence, patterns, and risk factors for clinically significant drug-drug interactions (CSDIs) in the prescription of HIV-infected patients receiving antiretroviral therapy (ART). Methods: A cross sectional study was conducted to review outpatient medical records of 1,000 HIV-infected patients who were attending and receiving ART in 2011. The severities of CSDIs were graded according to the Micromedex® 2.0 database and the 2012 DHHS HIV treatment guideline. Results: Of all patients, 333 (33%) had 554 CSDIs. Of 554 CSDIs, the prevalence of grade 2, 3, and 4 CSDIs were 61% (n = 337), 29% (n = 163), 10% (n = 54), respectively. Based on ART regimens, CSDIs were identified in protease inhibitor (PI)-based (79%), efavirenz-based (34%) and nevirapine-based regimens (10%) (P < 0.001). The three most frequent grade 4 CSDIs included PIs vs. simvastatin (n = 24), simvastatin vs. gemfibrozil (n = 24), and didanosine vs. allopurinol (n = 2). The three most frequent grade 3 CSDIs included PIs vs. statin drugs except simvastatin (n = 56), fenofibrate vs. statin drugs (n = 28), and amlodipine vs simvastatin (n = 14). In the multivariate analysis, risk factors associated with CSDIs were receiving PIs-based regimen
(OR = 13.9; 95% CI = 8.8–22.0), having dyslipidemia (OR = 3.8; 95% CI = 1.8–8.0), duration of ART > 5 years (OR = 2.2; 95% CI = 1.3–3.6), CD4 count > 200 cells/mm3 (OR = 2.1; 95% CI = 1.2–3.9), number of item > 5 per prescriptions (OR = 1.8; 95% CI = 1.2–2.7), and number of visits > 4 times a year (OR = 1.6; 95% CI = 1.1–2.3). Conclusion: CSDIs are highly prevalent among HIV-infected patients receiving ARV in the outpatient clinic. Patients with receiving PIbased ART, long duration of ART, low CD4 count, having dyslipidemia, having frequent number of visit a year and high number of item per prescription had a higher chance of occurring CSDIs. P97 Antimicrobial susceptibility of viridans group streptococci in Japan during 2009 and 2012 M. Minami1 *, M. Kuriyama1 , Y. Oshima1 , H. Nishiyama2 , S. Ikegami2 , M. Kawashima3 , M. Ohta4 . 1 Bacteriology, Nagoya City University, 2 Clinical Laboratory, Nagoya First Red Cross Hospital, 3 Clinical Laboratory, Nagoya Second Red Cross Hospital, 4 Nursing, Sugiyama Jogakuen University, Nagoya, Japan E-mail address : [email protected] Introduction: The viridans group streptococci make up a heterogeneous group of streptococci that inhabit the mouth, gastrointestinal tract and female genital tract and they are also the leading cause of invasive diseases such as subacute bacterial endocarditis, catheter- and neutropenia-related bloodstream infections. Objectives: The objective of this study was to determine the incidence and patterns of antimicrobial resistance among viridans group streptococci isolated in Japan. Methods: We determined the in-vitro susceptibilities of 11 antimicrobial agents (ABPC, PCG, SBT/ABPC, CTX, CFPM, MEPM, VCM, EM, CAM, LVFX, and ST) for 146 isolates of viridans group streptococci recovered from patients with invasive infections at Nagoya First Red Cross Hospital and Nagoya Second Red Cross Hospital in Japan during 2009 and 2012. Results: Variable degrees of susceptibility existed among 12 viridans group streptococcus species (Streptococcus acidominimus , Streptococcus anginosus , Streptococcus bovis , Streptococcus constellatus , Streptococcus gordonii , Streptococcus intermedius , Streptococcus mitis , Streptococccus mutans , Streptococcus oralis , Streptococcus parasanguinis , Streptococcus salivarius , and Streptococcus sanguinis ). In all, 15.1% of the isolates were non-susceptible to ABPC. Nine of 22 ampicillin non-susceptible isolates had high-level ABPC resistance (Streptococcus mitis 7, Streptococcus sanguinis 2). Rates of non-susceptibility to EM was 40.4% and EM resistance occurred most frequently in Streptococcus bovis isolates (100%), followed by Streptococcus oralis (62.5%), Streptococcus mitis (50%), and Streptococcus acidominimus (50%) but in none of Streptococcus gordonii . Although MEPM was the most active beta-lactam against penicillin-resistant isolates, 14.6% of Streptococcus mitis were non-susceptible to MEPM. Only one Streptococcus anginosus isolate had high-level resistance of VCM. Rates of non-susceptibility to LVFX was 12.3%, and high-level LVFX resistance was found in Streptococcus oralis (37.5%), and Streptococcus mitis (14.6%), respectively. Conclusion: These results indicate the species-related variability of susceptibility, especially to ABPC, EM and LVFX. The differences in susceptibilities among viridans group streptococci suggest the need for continuing surveillance of antimicrobial resistance. P98 Antimicrobial susceptibility of Citrobacter koseri isolated from clinical specimen in western part of Japan T. Muratani1,2,3 *, T. Kobayashi1 , M. Honda1 , Y. Haga1 , K. Doi1 , C. Nagahara1 , T. Matsumoto3 . 1 Hibiki Research Group for Clinical Microbiology, 2 Department of clinical microbiology, Kyurin medical laboratory, 3 Department of urology, University of Occupational and Environmental Health, Kitakyushu, Japan E-mail address : [email protected] Introduction: Multi-drug resistant Citrobacter koseri isolates have been isolated from various hospitals in western part of Japan, from 1999 onwards.
Posters / International Journal of Antimicrobial Agents 42S2 (2013) S41–S159
Objectives: To clarify the ratio of resistant isolates against various antimicrobials in C. koseri , we performed this study. Methods: We used total of 373 non-duplicate C. koseri isolated from various clinical specimen from 75 hospitals in western part of Japan in the period from 2008 to 2010. The MICs of various antimicrobials against the isolates were determined by the two-fold serial agar dilution method as described by the CLSI. The resistant isolates to antimicrobials were interpreted as showing more than following breakpoint MIC. Antimicrobials (their breakpoint MIC) used in this study as follows; ampicillin (8), piperacillin (8), piperacillin/ tazobactam (8/4), faropenem (2), cefazolin (8), cefotiam (8), cefmetazole (16), flomoxef (8), cefpodoxime (2), cefditoren (2), aztoreonam (8), imipenem (4), meropenem (4), levofloxacin (2), minocycline (4), gentamicin (4), tobramicin (4), amikacin (16), isepamicin (16), trimethoprim/sulfamethoxazole (2/38), and fosfomycin (64). Results: The susceptibility ratios of penicillins, faropenem, cephalosporins except ceftazidime and aztreonam against all 373 C. koseri isolates were less than 50%. The susceptibility ratios of piperacillin/ tazobactam, ceftazidime, cefmetazole, and flomoxef were 52.5, 52.8, 53.1, and 85.3, respectively. Imipenem and meropenem inhibited the growth of all 373 C. koseri isolates at 2 and 4 mcg/ml. The ratios of levofloxacin, minocycline, fosfomycin, and trimethoprim/sulfamethoxazole were 33.8, 39.9, 98.9, and 63.5%. Concerning aminoglycosides, the susceptibility ratios of tobramycin, gentamicin, amikacin, and isepamicin were 76.9, 81.2, 97.9, 98.4%. Six of all 373 isolates showed high aminoglycoside-resistance; the MIC of all aminoglycosides used were more than 128 mcg/ml. Twenty-five of all 373 isolates showed resistance against all antimicrobials except carbapenems, amikacin, tobramycin, and fosfomycin. Conclusion: Most of C. koseri isolates have acquired beta-lactam resistance. The major factors of mechanisms of resistance were plasmid-mediated beta-lactamases, such as CTX-M-2, CTX-M-15, SHV-12, DHA-1, etc. About 7% of all isolates have acquired multi-drug resistance. P99 In vitro antimicrobial property of Rhodomyrtus tomentosa (Ait.) Hassk. against Streptococcus agalactiae isolated from cultured tilapia P. Na-Phatthalung1 *, N. Suanyuk2 , S.P. Voravuthikunchai1 . Department of Microbiology, 2 Department of Aquaculture, Prince of Songkla University, Songkhla, Thailand E-mail address : [email protected]
1
Introduction: Streptocuccus agalactiae is an important fish pathogen in freshwater farms that resulted in a continuous decrease of tilapia production in aquaculture. Ethanol extract of Rhodomyrtus tomentosa leaf and its purified compound, rhodomyrtone has been previously demonstrated to possess a strong antibacterial activity against Grampositive pathogens. Objectives: The purpose of this study was to investigate the in vitro antimicrobial activity of the Rhodomyrtus tomentosa extract on S. agalactiae isolated from tilapia during an outbreak in Southern, Thailand. Methods: Antimicrobial activity of the ethanol extract was performed using broth microdilution method. Time-kill assay was also conducted to evaluate the bactericidal effect of the extract. Scanning electron microscope (SEM) was used to observe morphological changes of bacterial cells after exposure to the extract. In addition, the effect of an oxidative stress on bacterial cells after treatment with the extract was studied using hydrogen peroxide sensitivity assay. Results: Remarkable minimum inhibitory concentrations (MIC) of the Rhodomyrtus tomentosa extract against S. agalactiae (n = 10) were ranged from 31.25 to 62.5 mg/mL. The extract was demonstrated bacteriostatic activity against a representative strain in time-kill studies. Additionally, SEM revealed an irregular shape, different size, and nondividing of S. agalactiae cells after treated with sub-MIC (0.25×MIC) of Rhodomyrtus tomentosa extract. Interestingly, treatment with the extract at sub-MIC (0.125×MIC and 0.25×MIC) significantly increased sensitivity to hydrogen peroxide of exponential phase bacteria. Conclusion: These results suggested that Rhodomyrtus tomentosa is a promising candidate for a new antimicrobial agent against
S73
S. agalactiae which should be further study as an alternative for prevention and control of streptococcal infection in aquaculture. Using an antimicrobial agent base on natural source can reduce the residual levels of antibiotics in fish products and harmful effects to human health. Reference(s) Limsuwana S, et al . (2009) Phytomedicine. 16: 645–651.
P100 Antibiotic susceptiblity pattern of Klebsiella pneumoniae from clinical samples at a tertiary hospital in Ile-Ife, South Western Nigeria A.O. Oladipo1 *, S.J. Udoh1 . 1 Medical Microbiology and Parasitology, Obafemi Awolowo University Teaching Hospitals Complex (OAUTHC), Ile-Ife, Nigeria E-mail address : [email protected] Introduction: In the recent years, klebsiella pneumoniae has become important pathogen in nosocomial infections worldwide. All the isolates of klebsiella pneumoniae identified from January-December 2012 were subjected to antibiotic sensitivity testing on Mueller Hinton agar by modified Kirby–Bauer disc diffusion method using NCCLS guidelines. K. pneumoniae were most frequently isolated from urine 604 (42.5%), sputum 240 (29.9%) followed by blood 180 (42.9%), pus 86 (37.0%) and CSF with the least incidence of 34 (14.8%). All strains were resistant to antibiotics such as amoxycilin 64%, gentamicin 92.6%, erythromycin 82.3%, trimethoprim 88% sulfamethoxazole 96.3%, tetracycline 88.5%, ciprofloxacin 31.2%, nitrofurantoin 31.2%, ceftazidime 69%, cefotaxime 74%, ceftriaxone 79.6% while sensitivity to imipenem was 100% by all the organisms. This study suggested that there is a need for regular antibiotic stewardship and strict surveillance in the hospitals to prevent misuse of available antimicrobials. Keywords: Kebsiella pneumoniae , Gram-negative, noscomial infection Objectives: To determine the antibiotic susceptiblity pattern of k. pneumoniae isolated from samples of patients attending aTertiary Hospitals at Ile-Ife, Nigeria Methods: K. pneumoniae strains were identified by their morphology and biochemical characteristics according to the standards. Antibiotic sensitivity testing was done for all the isolates on Mueller–Hinton agar by modified Kirby–Bauer disc diffusion technique (Bauer, 1990). Results: 1144 clinical samples were cultured from various sites from patients at Obafemi Awolowo University Teaching Hospitals Complex, Ile-Ife. K. pneumoniae were most frequently isolated from urine 604 (42.5%), sputum 240 (29.9%) followed by blood 180 (42.9%), pus 86 (37.0%) and CSF with the least incidence of 34 (14.8%). All isolates were resistant to different antibiotics such as amoxycilin 64%, gentamicin 92.6%, erythromycin 82.3%, trimethoprim, Sulfamethoxazole 96.3% tetracycline 88.5%, ciprofloxacin 31.2% nitrofurantoin 31.2%, ceftazidime 69%, cefotaxime 74%, ceftriaxone 79.6% with all the organisms showing 100% sensitivity to imipenem. Conclusion: All of the strains isolated were sensitive to imipenem. A major increase in resistance and decrease in sensitivity was observed for all the drugs tested towards k. pneumoniae strains isolated from blood, sputum, urine, CSF and pus samples. This study suggested that there is also a need to emphasize on the rational use of antimicrobials and regular antimicrobial susceptibility surveillance is essential.
P101 Aeromonas species isolated from stool cultures and their susceptibilities to various antibiotics B. Ongen1 *, M. Ilktac1 , A. Aydın1 , H. Nazik1 . 1 Medical Microbiology Department, Istanbul University, Istanbul Medical Faculty, Istanbul, Turkey E-mail address : [email protected] Introduction: Aeromonas spp. are emerging agents of gastroenteritis. Since most of the species produce inducible type chromosomal betalactamase, resistance can develop during beta-lactam therapy [1].