APSIC Abstracts on Antimicrobial Resistance

The following abstracts on the topic of antimicrobial resistance are from the meeting of the eighth International Congress of the Asia Pacific Society of Infection Control (APSIC), held in Bangkok, Thailand, Feb. 12-15, 2017.

Reference: Antimicrobial Resistance & Infection Control. Abstracts from the 8th International Congress of the Asia Pacific Society of Infection Control (APSIC) Volume 6, Supplement 2. February 2017.

AR1: Key stakeholders’ perspectives on the underlying causes of antimicrobial resistance in Thailand

Nantanit Sutthiruk, Mari Botti, Julie Considine, Andrea Driscoll, Ana Hutchinson, Kumthorn Malathum

Background
Antimicrobial resistance (AMR) is a major problem worldwide. Antimicrobial stewardship (AMS) has the vital aim of ensuring optimal use of antimicrobial medicines to minimize AMR. New strategies are needed to reduce AMR. It is vital to ensure that key stakeholders are involved in the development of these strategies. This study aimed to examine key stakeholders’ perspectives on the underlying causes of AMR in Thailand.

Materials and methods
Semi-structured interviews were conducted with 15 key multidisciplinary clinicians, heads of department and healthcare administrators who were involved in AMS programs in a 1,000-bed university hospital in Bangkok Thailand. Qualitative content analysis was used to analyze the interview data.

Results
One of the key themes that emerged was lack of regulatory control resulting in widespread antibiotic availability and use both in health and agriculture in Thailand, including over-the-counter availability of antibiotics. This ease of accessibility combined with poor consumer knowledge was considered one of the most important contributors to the increasing prevalence of AMR. The development and implementation of more effective infection prevention and control strategies was identified as a priority, particularly in healthcare. Three major concerns related to the perception that many patients admitted to hospital already have AMR infections, that staff prescribing behaviors are not ideal, and that the lack of resources to develop and implement AMS programs is an important barrier to decreasing the overuse of antibiotics.

Conclusions
Participants recognized that AMR is a major problem in Thailand and in healthcare. There was agreement that what is required is better regulatory control of antibiotics and medical engagement in AMS.

AR2: Bacteriological profile of neurosurgical infections in a secondary care centre, Tangerang, Indonesia: implication for empirical antibiotic treatment

Cucunawangsih Cucunawangsih, Veronica Wiwing, Vivien Puspitasari

Background
Antimicrobial resistance is a major problem of post-operative neurosurgical infection over the recent years. This study aimed to evaluate an increasing trend of infection in neurosurgical patients and susceptibility pattern of the causative pathogen.

Material and methods
Over a period of five years (June 2010 to June 2015), 216 cerebrospinal fluid and pus samples derived from clinically suspected cases of post-operative neurosurgical infection were processed using the standard procedures for culture and antibiotic susceptibility testing.

Results
Of these 216 patients, causative pathogens were identified in 55 patients (25.5%). Majority of infections were caused by multidrug- resistant gram-negative bacilli (MDRGNB) including Pseudomonas aeruginosa (n = 7, 12.7%), Acinetobacter baumannii (n = 6, 10.9%), Sphingomonas paucimobilis (n = 5, 9.0%), Escherichia coli(n = 4, 7.3%), Aeromonas salmonocida (n = 3, 5.4%), and Klebsiella pneumoniae (n = 3, 5.4%). The common isolates showed a high susceptibility to tigecycline (86.7%) and amikacin (90%), ceftriaxone (76.9%) and ceftazidime (70%). All Gram-positive bacteria isolates were susceptible to tigecycline and vancomycin.

Conclusions
Based on our result of susceptibility pattern, a combination of tigecycline and amikacin should be considered for empirical therapy to treat MDRGNB infections. This finding pointed that strict antibiotic policies were required to work out the issue of emerging MDR-GNB infections.

AR3: A newly developed single-strand tag hybridization – printed array strip technique for identification of carbapenemase-producing Enterobacteriaceae

Rathina Kumar Shanmugakani, Yukihiro Akeda, Takuya Kodera, PitakSantanirand5, Kazunori Tomono

Background
Carbapenem resistant organisms are known to risk the life of both immunocompromised and immunocompetent patients due to their resistance towards the drug of the last resort. In carbapenemase-producing Enterobacteriaceae (CPE), carbapenemase genes serve as the main reservoir of carbapenem resistance due to their plasmid-mediated transferability to naïve Enterobacteriaceae. In this regard, CPE infections are a global health issue due to their hasty dissemination throughout the world. The detection of CPE at the earliest is crucial to control its transmission. Several detection systems are being developed and modified for CPE detection but have various constraints in different criteria.

Materials and methods
We attempted to develop single-strand tag hybridization –printed array strip (STH-PAS), a new genotypic multiplex detection system to detect CPE directly in clinical samples. STH-PAS is a PCR-based technique that targets the four major carbapenemase genes - bla NDM, bla KPC, bla IMP, and bla OXA-48 for CPE detection. The sensitivity and specificity of STH-PAS in detecting the CPE were determined for the clinical isolates and direct clinical specimens.

Results

STH-PAS showed 100% sensitivity and specificity in detecting the CPE clinical isolates in comparison with the culture methods and PCR. For detection of CPE directly in stool specimens, STH-PAS showed a sensitivity and specificity of 92% and 99.4%, respectively.

Conclusions
The results of the current study depict that STH-PAS possesses several advantages as a good detection system for CPE. The simplicity and rapidity of STH-PAS show that it could serve as an effective tool for surveillance and infection control purposes

AR4: Invasive infections due to multidrug-resistant gram-negative bacilli among Japanese children

Takayuki Yamanaki, Hiroyuki Moriuchi, Hiroyuki Kitajima, Yuho Horikoshi

Background
Although multidrug-resistant (MDR) gram-negative bacilli (GNB) become a global concern, the disease burden of MDR GNB in children has not been reported yet in Japan. We elucidate the impact of invasive MDR GNB infections among Japanese children in the hospital setting.

Materials and methods
A primary questionnaire was sent to 520 pediatric training facilities. A secondary questionnaire was sent to determine whether any cases showed a positive blood or cerebral spinal fluid culture for Extended Spectrum Beta-lactamase (ESBL) producing GNB, AmpC β-lactamases producing GNB, or carbapenem-resistant enterobacteriacae (CRE) between April 2012 and March 2015.The following data were collected; demographic data pertaining to both the care facilities and patients, clinical diagnosis, and outcomes.

Results
The response rate for the primary questionnaire was 57%. Among facilities that responded, 66 facilities were eligible for the secondary questionnaire. The response rate for secondary questionnaire was 48%. A total of 92 pediatric patients had invasive MDR GNB infection. The median age was 2.5 years old (interquartile range 3 months–10 years old). The number of patients with bacteremia caused by ESBL GNB, AmpC GNB, and CRE were 66 (72%), 22 (24%), and 4 (4%), respectively. The clinical diagnosis of ESBL and AmpC GNB showed 53 cases of sepsis. The clinical diagnosis of CRE showed 2 cases of catheter related blood stream infection and 2 cases of sepsis. Mortality at 30 days for ESBL, AmpC and CRE bacteremia was 6%, 9% and 0%, respectively.

Conclusions
The most common MDR GNB bacteremia was ESBL GNB among children in this survey.

AR5: The role of non-specific microflora in patients with tuberculosis

Alyona Lavrinenko, Ilya Azizov, Nurlan Tabriz, Margulan Kozhamuratov, Yekatherine Serbo

Background
Tuberculosis is often complicated by the addition of non-specific inflammation, which changes not only the clinical manifestation of tuberculosis, but the course and outcome of disease. This study aimed to study the spectrum of non-specific microflora from patients with active tuberculosis and to evaluate its susceptibility to antimicrobial agents.

Materials and methods
The study was conducted in 2014-2015; 343 sputum samples were investigated. Identification of microorganisms was carried out by MALDI-TOF methods using mass-spectrometer Microflex (Bruker Daltonics, Germany). The sensitivity of microorganisms to antibiotics was determined by disk-diffusion methods (CLSI 2012). Statistical processing and data analysis was performed using WhoNet 6.3 program.

Results
The growth of non-specific microflora in patients with tuberculosis was obtained in 21% of cases. The predominant etiologic role in non-specific inflammation belonged to S. aureus (22%), K. pneumoniae were isolated in 12.5%, A. baumannii – in 11.1%. Remaining microorganisms were isolated in individual cases. 12.5% staphylococci were MRSA, to other anti-staphylococcal drugs S. aureus has kept a high sensitivity. Isolated K. pneumoniae strains were resistant to cephalosporins of the 3rd generation in 12.5%, the resistance to meropenem marked in 11.1%. A. baumannii was characterized by a high resistance to antibiotics – 85.7% ESBL-producing strains, 37.5% and 62.5% strains were resistant to imipenem and meropenem, 80% A. baumannii strains were resistant to fluoroquinolones.

Conclusions
According to antibioticogram data, the isolated microorganisms obtained from non-specific microflora of patients with tuberculosis, may adversely affect the course of the disease and impede the selection of antibacterial drugs and affect the outcome of the disease.

AR6: Antimicrobial susceptibility of clinical isolates of Enterococcus faecium and Enterococcus faecalis in Korea

Dahae Yang, Woonhyoung Lee, Il Kwon Bae, Jae Hyun Lee, Hyukmin Lee, Jung Ok Kim, Seok Hoon Jeong, Kyungwon Lee

Background
Enterococcus species become a leading problem of nosocomial infections with their multidrug resistance (MDR) potential. This study was performed to investigate antimicrobial susceptibility of E. faecium and E. faecalis clinical isolates in Korea.

Materials and methods
A total of 152 non-duplicated E. faecium and 112 E. faecalis isolates recovered from clinical blood specimen were collected from 19 hospitals at various regions in Korea during 2014. Species identification was performed using MALDI-TOF (Bruker) and 16S rRNA gene sequencing. Antimicrobial susceptibility was tested by CLSI disk diffusion methods. The presence of vanA and vanB genes was detected by PCR experiments.

Results
All E. faecalis isolates were susceptible to ampicillin, while only 11.8% (18/152) E. faecium isolates were susceptible. E. faecalis isolates (96.4%, 108/112) exhibited higher susceptibility rate to vancomycin than E. faecium isolates (66.4%, 101/152). None of E. faecalis and E. faecium isolates showed resistance to linezolid. Only 52.6% (80/152) of E. faecium isolates were susceptible to quinupristin-dalfopristin. E. faecalis and E. faecium isolates exhibited high-level resistance to gentamicin (50% and 57.9%, respectively). PCR experiments showed that all vancomycin-resistant E. faecium and E. faecalis isolates carried the vanA. Interestingly, two vancomycin-susceptible E. faecalis and three vancomycin-susceptible E. faecium isolates carried the vanA gene.

Conclusions
This study shows further dissemination of MDR enterococci in Korea. Antimicrobial susceptibility of quinupristin-dalfopristin and gentamicin for E. faecium has lowered to near 50%. Discrepancy between antimicrobial susceptibility tests and PCR for vanA gene might be due to loss of some elements consisting transposon Tn1546 carrying the vanA gene.

AR7: Antifungal susceptibilities, biofilms, phospholipase and protease activities in Candida rugosa and Candida pararugosa isolated from tertiary teaching hospitals

Thiba Peremalo, Priya Madhavan, Sharina Hamzah, Leslie Than, Eng Hwa Wong, Mohd Nasir Mohd Desa, Kee Peng Ng

Background
Rising number of candidiasis significantly contribute towards resistance of commonly used antifungal agents. Lately, Candida species such as C. rugosa and C. pararugosa have emerged as fungal pathogens that cause invasive infections.

Material and methods
Clinical isolates were from two tertiary referral hospitals in Malaysia. Test for antifungal susceptibility, biofilm, protease and phospholipase activities, all of which contribute to their virulence were performed. Biofilms were quantified using crystal violet (CV) and tetrazolium (XTT) reduction assays in 96-well microtiter plates. Time point reading was done on all strains incubated at 6, 12, 24, 48 and 72 hours.

Results
There were seven isolates of C. rugosa and one isolate of C. pararugosa in this study. E-test antifungal tests showed that all Candida rugosa strains were susceptible-dose dependent towards voriconazole and resistant to fluconazole, amphotericin B and caspofungin based on Clinical and Laboratory Standard Institute guidelines. Highest biomass was observed in one of the C. rugosa strains, followed by C. pararugosa at 12 hours of incubation. However, highest bioactivity was observed in the ATCC at 24 hours, followed by C. pararugosa at 48 hours and the same C. rugosa train at 24 hours. Virulence was also contributed by secretion of protease enzymes by all the clinical strains. None of the C. rugosa and C. pararugosa trains showed any phospholipase activity.

Conclusions
C. rugosa and C. pararugosa clinical isolates should be considered pathogenic species because of their resistance against commonly used antifungal drugs and their contributing virulence factors.

AR8: Comparison of antimicrobial resistance of respiratory isolates after introduction of a second tier of antimicrobial stewardship program in the medical city hospital

Marionne Geronimo, Maria Fe Tayzon, Maria Jesusa Maño

Background
In response to an antimicrobial resistance "apocalypse" The Medical City, a private tertiary hospital in the Philippines, conducts microbiologic surveillance and has an existing "prior approval of restricted antibiotics" wherein release of identified broad spectrum antibiotics were done only upon approval of ID consultants. In June 2015, a second tier of ASP was introduced. The "drug duration, audit and feedback" (DDAF) program monitors and audits the duration of empiric antibiotics prescribed by clinicians. Sticker reminders are being placed on the chart on day 3 as a reminder to de-escalate and on day 10 as a reminder to consider stopping the antibiotics. This study aimed to present a comparative study of the antimicrobial resistance of the top 3 bacteriologic agents from respiratory isolates in a tertiary care hospital in the Philippines, from January to June 2015 versus January to June 2016, as a surrogate marker to the success of the second tier of ASP recently introduced

Materials and methods
Most prevalent organisms from sputum, endotracheal aspirate and bronchoalveolar lavage were determined through laboratory surveillance comparing their resistance pattern from January to June 2015 versus January to June 2016.

Results
The top 3 respiratory pathogens in the ICU were identified. Some decrease in the resistance data of the most common isolate, Klebsiella pneumoniae were as follows: 12% decrease in resistance to ceftriaxone, 9% to levofloxacin and 4% to piperacillin-tazobactam. Similar decreases in resistance were seen with Pseudomonas aeruginosa and other organisms.

Conclusions
The study showed decrease in resistance of most common bacteriologic agents from respiratory isolates upon introduction of DDAF program.

AR9: Do daily universal octenidine baths lead to the development of octenidine resistance in methicillin-resistant Staphylococcus aureus (MRSA)?

Angela Chow, Pei-Yun Hon, Mar-Kyaw Win, Brenda Ang, Yee-Sin Leo

Background
Methicillin-resistant Staphylococcus aureus (MRSA) colonization has not declined in acute hospitals, despite active surveillance and enhanced contact precautions. Universal antiseptic baths could reduce MRSA transmission, but there are concerns about antiseptic resistance. To evaluate the prevalence of octenidine resistance in MRSA isolated from inpatients exposed to octenidine baths during hospitalization.

Materials and methods
We conducted a cross-sectional study, testing for resistance to octenidine in MRSA isolates obtained from discharge screening cultures from inpatients of a dermatology/infectious disease ward from July 2013 to June 2014. During that period, daily universal octenidine baths was implemented in the ward. The minimum inhibitory concentration (MIC) of octenidine was determined by the modified Clinical and Laboratory Standards Institute (CLSI) methods, with microbroth dilution susceptibility testing for a range of 0.125-8 ug/ml. There is no defined MIC breakpoint for antiseptics by CLSI.

Results
Of 600 patients screened negative for MRSA on entry to the ward, 21 were identified to be colonized with MRSA at discharge. Eighteen of the isolates were available for resistance testing. Median duration of exposure to octenidine baths was 8.5 (IQR 7-12) days. Majority (77.8%) of isolates had MIC = 0.5, with the remaining had MIC = 1. Duration of exposure to antiseptic baths was not associated with higher octenidine MIC levels (OR 0.84, 95%CI 0.62-1.12, P = 0.236).

Conclusions
Resistance to octenidine in MRSA was not observed among patients who were colonized during a hospitalization episode where they were exposed to daily octenidine baths. This study is limited by the small number of MRSA acquisitions and the findings should be verified in larger studies.

AR10: Antiseptic susceptibility in methicillin-resistant Staphylococcus aureus (MRSA) in subacute wards

Angela Chow, Pei-Yun Hon, Tina See, Brenda Ang

Background
Methicillin-resistant Staphylococcus aureus (MRSA) is a growing clinical problem in subacute wards where patients have a longer length of stay than in acute wards. Universal antiseptic baths could be added to the armamentarium for MRSA prevention and control. Our study aimed to assess for the baseline antiseptic susceptibilities in MRSA, prior to the institution of universal antiseptic baths in subacute wards.

Materials and methods
We conducted a cross-sectional study, testing for susceptibilities to chlorhexidine and octenidine in MRSA isolates obtained from inpatients of two subacute wards from May-July 2013. Minimum inhibitory concentrations (MICs) of chlorhexidine and octenidine were determined by the modified Clinical and Laboratory Standards Institute (CLSI) methods, with microbroth dilution susceptibility testing for a range of 0.125-8 ug/ml.

Results
A total of 43 MRSA isolates were tested: 10 in May, 14 in June, and 19 in July. For chlorhexidine, all except for one had MIC = 2. The remaining with MIC = 4 had occurred in July 2013. In comparison, the majority (90.7%) of the isolates had MIC = 0.5 when tested for octenidine susceptibility, with the remaining having an MIC = 1. A higher proportion of MRSA isolates with the higher MIC level (MIC = 1) to octenidine was observed in June 2013 than in the other months, although statistical significance was not achieved due to the small sample size (OR 7.64, 95%CI 0.72-81.54, P = 0.092).

Conclusions
MRSA isolated from patients from subacute wards were highly susceptible to chlorhexidine and octenidine. Universal antiseptic baths could be implemented in subacute wards, with follow-up studies conducted to monitor for any development of antiseptic resistance.

AR11: Antimicrobial activity of octenidine against multidrug-resistant gram-negative pathogens

Rocio Alvarez Marin, Marta Aires de Sousa, Nicolas Kieffer, Patrice Nordmann1, Laurent Poirel

Background
Multidrug-resistant gram-negative (MRGN) pathogens pose a major and growing threat for healthcare systems, as therapy of infections is often limited due to the lack of available systemic antibiotics. Well tolerated antiseptic molecules may be a very useful implementation in infection control,not only to reduce the dissemination of methicillin-resistant Staphylococcus aureus (MRSA), but also MRGN.

Material and methods
As decolonization strategies with regard to MRSA are already implemented in high risk areas (i.e. ICUs), this study aimed to investigate, if the same protocol might be concomitantly efficient against MRGN. A series of 5 different species (Escherichia coli, Klebsiella pneumoniae, Enterobacter cloacae, Acinetobacter baumannii, Pseudomonas aeruginosa) was studied to prove efficacy under clinically relevant conditions according to an official test norm (EN13727). We used 5 clonally-unrelated isolates per species, including a single wild-type strain, and four MRGN isolates, corresponding either to the 3 MGRN or 4 MGRN definition of multidrug resistance. Octenidine (OCT, Schuelke&Mayr GmbH, Germany) susceptibility was evaluated with and without organic load.

Results
A contact time of 30 seconds or 1 minute was fully effective for all isolates by using different OCT concentrations (0.01% and 0.05%), with a bacterial reduction factor of >5 log systematically observed. Growth kinetics were determined with two different wild-type strains (A. baumannii and K. pneumoniae), proving a time-dependent efficacy of OCT, mirroring what has been previously observed for MRSA.

Conclusions
These results highlight that OCT, besides being a very effective agent against MRSA, may also be extremely useful to eradicate emerging highly resistant gram-negative pathogens associated with nosocomial infections.

AR12: Comparison of mortality of patients with Acinetobacter baumannii bacteremia caused by different levels of drug resistance

Wison Laochareonsuk, Sireekul Petyu, Pawin Wanasitchaiwat, Sutasinee Thana, Chollathip Bunyaphongphan, Woranan Boonsomsuk, Pakpoom Maneepongpermpoon, Silom Jamulitrat

Background
Acinetobacter baumannii is an important opportunistic nosocomial pathogen causing a variety of infections. The intrinsic virulence of drug-resistant A. baumannii has remained controversial. We compared mortality rates and sepsis score of patients with A. baumannii bacteremia caused by different level of drug resistance.

Materials and methods
A retrospective study was conducted in adult patients (age > 15 years) admitted to Songklanagarind hospital during 2009 and 2015 and blood culture positive for A. baumannii after 3 days of admission. Antimicrobial resistance was categorized into four levels comprising of non-multidrug resistance (non-MDR), multidrug-resistant (MDR), extensively drug-resistant (XDR), and possible pandrug-resistant (possible-PDR). Severity of underlying disease of the patients immediately before onset of bacteremia was determined by sequential organ failure (SOFA) score and American Association of Anesthesia (ASA) score. Virulence of A. baumannii was assessed in terms of sepsis score and in hospital mortality rate.

Results
The study identified 38, 110, 168, and 14 cases of bacteremia caused by non-MDR, MDR, XDR, and possible PDR, respectively. After adjusting for confounding effect by using Cox proportional hazard model, mortality rates attributable to A. baumannii was significantly associated to levels of drug resistance. Using non-MDR as a reference, the incidence rate ratios and corresponding 95% confidence intervals (95% C.I) of MDR, XDR, and possible PDR were 2.3 (95% C.I = 0.9-4.9), 3.1(95% C.I = 1.4-7.0), and 1.9(95% C.I = 0.6-5.5) respectively.

Conclusions
The virulence of A. baumannii did not loss with drug resistance.