Results from the Survey of Antibiotic Resistance (SOAR) 2009-11 in Vietnam

Country data on AMR in Vietnam in the context of community-acquired respiratory tract infections: links between antibiotic susceptibility, local and international antibiotic prescribing guidelines, access to medicines and clinical outcome

Background

Antimicrobial resistance (AMR) is one of the biggest threats to global public health. Selection of resistant bacteria is driven by inappropriate use of antibiotics, amongst other factors. COVID-19 may have exacerbated AMR due to unnecessary antibiotic prescribing. Country-level knowledge is needed to understand options for action.

Objectives

To review the current situation with respect to AMR in Vietnam and initiatives addressing it. Identifying areas where more information is required will provide a call to action to minimize any further rises in AMR within Vietnam and improve patient outcomes.

Methods

National initiatives to address AMR in Vietnam, antibiotic use and prescribing, and availability of susceptibility data, in particular for the key community-acquired respiratory tract infection (CA-RTI) pathogens Streptococcus pneumoniae and Haemophilus influenzae, were identified. National and international antibiotic prescribing guidelines for CA-RTIs (community-acquired pneumonia, acute otitis media and acute bacterial rhinosinusitis) commonly used locally were also reviewed, plus local antibiotic availability. Insights from clinicians in Vietnam were sought to contextualize this information.

Conclusions

In Vietnam there have been some initiatives addressing AMR; Vietnam was the first country in the Western Pacific Region to develop a national action plan to combat AMR, which according to the WHO is being implemented. Vietnam also has one of the highest rates of AMR in Asia due, in part, to the overuse of antimicrobial drugs, both in the animal health sector and in humans in both hospitals and the community. In addition, despite a 2005 law requiring antibiotic prescription, there is unrestricted access to over-the-counter antibiotics. Several global surveillance studies provide antibiotic susceptibility data for CA-RTI pathogens in Vietnam including Survey of Antibiotic Resistance (SOAR) and SENTRY (small isolate numbers only). For management of the common CA-RTIs in Vietnam there are several country-specific local antibiotic prescribing guidelines and in addition, there is a range of international guidelines referred to, but these may have been created based on pathogen resistance patterns that might be very different to those in Vietnam. Expert clinician opinion confirms the high resistance rates among common respiratory pathogens. A more standardized inclusive approach in developing local guidelines, using up-to-date surveillance data of isolates from community-acquired infections in Vietnam, could make management guideline use more locally relevant for clinicians. This would pave the way for a higher level of appropriate antibiotic prescribing and improved adherence. This would, in turn, potentially limit AMR development and improve clinical outcomes for patients.

Results from the Survey of Antibiotic Resistance (SOAR) 2016-18 in Vietnam, Cambodia, Singapore and the Philippines: data based on CLSI, EUCAST (dose-specific) and pharmacokinetic/pharmacodynamic (PK/PD) breakpoints

OBJECTIVES

To determine antibiotic susceptibility of Streptococcus pneumoniae and Haemophilus influenzae isolates collected from community-acquired respiratory tract infections (CA-RTIs) in 2016-18 in four Asian countries.

METHODS

MICs were determined by CLSI broth microdilution and susceptibility was assessed using CLSI, EUCAST (dose-specific) and pharmacokinetic/pharmacodynamic (PK/PD) breakpoints.

RESULTS

In total, 260 S. pneumoniae and 258 H. influenzae isolates were tested. Pneumococci from Vietnam (n = 161) were the least susceptible, with rates of susceptibility >90% for fluoroquinolones by CLSI breakpoints, ∼60% for amoxicillin, amoxicillin/clavulanic acid and ceftriaxone but <14% for most other agents. Pneumococcal isolates from Cambodia (n = 48) and Singapore (n = 34) showed susceptibilities ranging from ∼30% for trimethoprim/sulfamethoxazole and oral penicillin to 100% for fluoroquinolones. Among isolates of H. influenzae from Cambodia (n = 30), the Philippines (n = 59) and Singapore (n = 80), rates of susceptibility using CLSI breakpoints were >90% for amoxicillin/clavulanic acid, cephalosporins [except cefaclor in Singapore (77.5%)], macrolides and fluoroquinolones; for isolates from Vietnam (n = 89) the rates of susceptibility were >85% only for amoxicillin/clavulanic acid (95.5%), ceftriaxone (100%) and macrolides (87.6%-89.9%). Susceptibility to other antibiotics ranged from 7.9% (trimethoprim/sulfamethoxazole) to 57.3%-59.6% (fluoroquinolones) and 70.8% (cefixime). The application of different EUCAST breakpoints for low and higher doses for some of the antibiotics (amoxicillin, amoxicillin/clavulanic acid, ampicillin, penicillin, ceftriaxone, clarithromycin, erythromycin, levofloxacin and trimethoprim/sulfamethoxazole) allowed, for the first time in a SOAR study, the effect of raising the dosage on susceptibility to be quantified. A limitation of the study was the small sample sizes and only one or two sites participating per country; however, since susceptibility data are scarce in some of the participating countries any information concerning antibiotic susceptibility is of value.

CONCLUSIONS

Antibiotic susceptibility varied across countries and species, with isolates from Vietnam demonstrating the lowest susceptibility. Knowledge of resistance patterns can be helpful for clinicians when choosing empirical therapy options for CA-RTIs.

The Role of PK/PD Analysis in the Development and Evaluation of Antimicrobials

Pharmacokinetic/pharmacodynamic (PK/PD) analysis has proved to be very useful to establish rational dosage regimens of antimicrobial agents in human and veterinary medicine. Actually, PK/PD studies are included in the European Medicines Agency (EMA) guidelines for the evaluation of medicinal products. The PK/PD approach implies the use of in vitro, ex vivo, and in vivo models, as well as mathematical models to describe the relationship between the kinetics and the dynamic to determine the optimal dosing regimens of antimicrobials, but also to establish susceptibility breakpoints, and prevention of resistance. The final goal is to optimize therapy in order to maximize efficacy and minimize side effects and emergence of resistance. In this review, we revise the PK/PD principles and the models to investigate the relationship between the PK and the PD of antibiotics. Additionally, we highlight the outstanding role of the PK/PD analysis at different levels, from the development and evaluation of new antibiotics to the optimization of the dosage regimens of currently available drugs, both for human and animal use.

Antimicrobial susceptibility testing results from 13 hospitals in Viet Nam: VINARES 2016-2017

OBJECTIVE

To analyse data from 2016-17 from a hospital-based antimicrobial resistance surveillance with national coverage in a network of hospitals Viet Nam.

METHODS

We analysed data from 13 hospitals, 3 less than the dataset from the 2012-13 period. Identification and antimicrobial susceptibility testing data from the clinical microbiology laboratories from samples sent in for routine diagnostics were used. Clinical and Laboratory Standards Institute 2018 guidelines were used for antimicrobial susceptibility testing interpretation. WHONET was used for data entry, management and analysis.

RESULTS

42,553 deduplicated isolates were included in this analysis; including 30,222 (71%) Gram-negative and 12,331 (29%) Gram-positive bacteria. 8,793 (21%) were from ICUs and 7,439 (18%) isolates were from invasive infections. Escherichia coli and Staphylococcus aureus were the most frequently detected species with 9,092 (21%) and 4,833 isolates (11%), respectively; followed by Klebsiella pneumoniae (3,858 isolates - 9.1%) and Acinetobacter baumannii (3,870 isolates - 9%). Bacteria were mainly isolated from sputum (8,798 isolates - 21%), blood (7,118 isolates - 17%) and urine (5,202 isolates - 12%). Among Gram-positives 3,302/4,515 isolates (73%) of S. aureus were MRSA; 99/290 (34%) of Enterococcus faecium were resistant to vancomycin; and 58% (663/1,136) of Streptococcus pneumoniae proportion were reduced susceptible to penicillin. Among Gram-negatives 59% (4,085/6,953) and 40% (1,186/2,958) of E. coli and K. pneumoniae produced ESBL and 29% (376/1,298) and 11% (961/8,830) were resistant to carbapenems, respectively. 79% (2855/3622) and 45% (1,514/3,376) of Acinetobacter spp. and Pseudomonas aeruginosa were carbapenem resistant, respectively. 88% (804/911) of Haemophilus influenzae were ampicillin resistant and 18/253 (7%) of Salmonella spp. and 7/46 (15%) of Shigella spp. were resistant to fluoroquinolones. The number of isolates from which data were submitted in the 2016-2017 period was twice as high as in 2012-2013. AMR proportions were higher in 2016-2017 for most pathogen-antimicrobial combinations of interest including imipenem-resistant A. baumannii, P. aeruginosa and Enterobacterales.

CONCLUSIONS

The data show alarmingly high and increasing resistant proportions among important organisms in Viet Nam. AMR proportions varied across hospital types and should be interpreted with caution because existing sampling bias and missing information on whether isolates were community or hospital acquired. Affordable and scalable ways to adopt a sample- or case-based approach across the network should be explored and clinical data should be integrated to help provide more accurate inferences of the surveillance data.

Improved penicillin susceptibility of Streptococcus pneumoniae and increased penicillin consumption in Japan, 2013-18

OBJECTIVES

To examine the association between penicillin susceptibility of Streptococcus pneumoniae and penicillin consumption in Japan.

METHODS

We used Japan Nosocomial Infection Surveillance data on the susceptibility of S. pneumoniae and sales data obtained from IQVIA Services Japan K.K. for penicillin consumption. We analysed both sets of data by decomposing them into seasonality and chronological trend components. The cross-correlation function was checked using Spearman's rank correlation coefficient to examine the correlation between susceptibility and consumption.

RESULTS

After adjusting for seasonality, the susceptibility of S. pneumoniae to penicillins gradually improved (55.7% in 2013 and 60.6% in 2018, respectively) and penicillin consumption increased during the same period (0.76 defined daily doses per 1,000 inhabitants per day [DID] in 2013, and 0.89 DID in 2018). The results showed positive cross-correlation (coefficient 0.801, p-value < 0.001). In contrast, cephalosporin consumption decreased (3.91 DID in 2013 and 3.19 DID in 2018) and showed negative cross-correlation with susceptibility of S. pneumoniae to penicillins (coefficient -0.981, p-value < 0.001).

CONCLUSIONS

The rates of penicillin-susceptible S. pneumoniae isolates did not negatively correlate with penicillin consumption at the population level. Increased penicillin consumption might not impair the penicillin susceptibility of S. pneumoniae.

Hospital surveillance predicts community pneumococcal antibiotic resistance in Vietnam

BACKGROUND

In Vietnam, Streptococcus pneumoniae is a leading cause of disease, including meningitis. Antibiotics are available without physician prescription at community pharmacies and rates of antibiotic non-susceptibility are high. Appropriate treatment and antibiotic stewardship need to be informed by surveillance data.

OBJECTIVES

To report community-based pneumococcal antibiotic susceptibility testing data from children enrolled in a pneumococcal conjugate vaccine trial in Ho Chi Minh City [the Vietnam Pneumococcal Project (ViPP)] and compare these with published hospital-based data from the nationwide Survey of Antibiotic Resistance (SOAR) to determine whether hospital surveillance data provide an informative estimate of circulating pneumococcal resistance.

METHODS

Pneumococcal isolates from 234 nasopharyngeal swabs collected from ViPP participants at 12 months of age underwent antibiotic susceptibility testing using CLSI methods and the data were compared with SOAR data.

RESULTS

Antibiotic susceptibility testing identified penicillin-non-susceptible pneumococci in 93.6% of pneumococcus-positive ViPP swabs (oral, non-meningitis breakpoints). Non-susceptibility to erythromycin, trimethoprim/sulfamethoxazole, clindamycin and tetracycline also exceeded 79%. MDR, defined as non-susceptibility to three or more classes of antibiotic, was common (94.4% of swabs). Low or no resistance was detected for ceftriaxone (non-meningitis breakpoints), ofloxacin and vancomycin. Antibiotic non-susceptibility rates in ViPP and SOAR were similar for several antibiotics tested.

CONCLUSIONS

A very high proportion of pneumococci carried in the community are MDR. Despite wide disparities in population demographics between ViPP and SOAR, the non-susceptibility rates for several antibiotics were comparable. Thus, with some qualification, hospital antibiotic susceptibility testing data in Vietnam can inform circulating pneumococcal antibiotic non-susceptibility in young children, the group at highest risk of pneumococcal disease, to guide antibiotic prescribing and support surveillance strategies.

Essential Oils of Zingiber Species from Vietnam: Chemical Compositions and Biological Activities

Mosquito-borne diseases are a large problem in Vietnam as elsewhere. Due to environmental concerns regarding the use of synthetic insecticides as well as developing insecticidal resistance, there is a need for environmentally-benign alternative mosquito control agents. In addition, resistance of pathogenic microorganisms to antibiotics is an increasing problem. As part of a program to identify essential oils as alternative larvicidal and antimicrobial agents, the leaf, stem, and rhizome essential oils of several Zingiber species, obtained from wild-growing specimens in northern Vietnam, were acquired by hydrodistillation and investigated using gas chromatography. The mosquito larvicidal activities of the essential oils were assessed against Culex quinquefasciatus, Aedes albopictus, and Ae. aegypti, and for antibacterial activity against a selection of Gram-positive and Gram-negative bacteria, and for activity against Candida albicans. Zingiber essential oils rich in α-pinene and β-pinene showed the best larvicidal activity. Zingiber nudicarpum rhizome essential oil showed excellent antibacterial activity against Enterococcus faecalis, Staphylococcus aureus, and Bacillus cereus, with minimum inhibitory concentrations (MIC) of 2, 8, and 1 μg/mL, respectively. However, the major components, α-pinene and β-pinene, cannot explain the antibacterial activities obtained.

Antibiotic use in children hospitalised with pneumonia in Central Vietnam

BACKGROUND AND OBJECTIVES

Excessive use of antibiotics has been noted in children with respiratory tract infections in Vietnam, but antibiotic use in hospitalised children is poorly documented. Antibiotic use and direct healthcare costs in children hospitalised with pneumonia in central Vietnam were assessed.

METHODS

A prospective descriptive study of children under 5 years old admitted with a primary admission diagnosis of 'pneumonia' to the Da Nang Hospital for Women and Children over 1 year.

RESULTS

Of 2911 children hospitalised with pneumonia, 2735 (94.0%) were classified as 'non-severe' pneumonia by the admitting physician. In total, 2853 (98.0%) children received antibiotics. Intravenous antibiotics were given to 336 (12.3%) children with 'non-severe' and 157/176 (89.2%) children with 'severe' pneumonia; those with 'non-severe' pneumonia accounted for 68.2% (336/493) of intravenous antibiotics given. Only 19.3% (95/493) of children on intravenous antibiotics were stepped down to an oral antibiotic. Cefuroxime was the preferred oral agent, and ceftriaxone was the preferred injectable agent. Hospital admission for oral antibiotics in 'non-severe' pneumonia was a major cost driver, with an average direct cost of US$78.9 per patient, accounting for 54.0% of the total hospitalisation cost in the study cohort. In addition, 336 (12.3%) children with non-severe pneumonia received intravenous antibiotics without indication, accounting for a further 23.2% of hospitalisation costs.

CONCLUSION

Limiting unnecessary hospitalisation and considering early intravenous to oral step down antibiotic will reduce direct health system costs and morbidity in children with respiratory tract infections in Vietnam.

Genotoxic and cytotoxic alterations induced by environmentally-relevant concentrations of amoxicillin in blood cells of Cyprinus carpio

Amoxicillin (AMX) is a pharmaceutical widely employed in human and veterinary medicine worldwide. Its wide production and use has led to this pharmaceutical being released into the environment in concentrations that range from ng L^-1 to μg L^-1. Previous studies have demonstrated that this antibiotic generates toxic effects, amongst which alterations to embryonic development and oxidative stress in aquatic organisms, is noteworthy. Nonetheless, it is necessary to characterize the risks that this pharmaceutical represents for species of economic interest such as Cyprinus carpio, in a more precise manner. The aim of this work was to demonstrate if AMX, at environmentally-relevant concentrations, is capable of inducing genotoxic/cytotoxic alterations in C. carpio. In order to evaluate genotoxicity, the comet assay and micronucleus test were used; in order to determine cytotoxic effects, caspase-3 activity and the TUNEL assay were carried out. The results showed that the effects of the biomarkers had their maximum at 72 h; considering the DNA damage in the comet assay, 0.039 μg L^-1 resulted in a 29% increase compared to control, and 1.67 μg L^-1 caused a 40% increase; micronucleus frequency increased by 205% in C1 and by 311% in C2 when compared to control; compared to control, caspase-3 activity increased 262% in C1 and 787% in C2; for the TUNEL assay, DNA fragmentation increased by 86% in C1 and 120% in C2 compared to control. The results showed that environmentally-relevant concentrations, AMX was capable of generating DNA damage and cytotoxic effects in blood cells of the common carp.

Antimicrobial susceptibility testing and antibiotic consumption results from 16 hospitals in Viet Nam: The VINARES project 2012-2013

OBJECTIVE

To establish a hospital-based surveillance network with national coverage for antimicrobial resistance (AMR) and antibiotic consumption in Viet Nam.

METHODS

A 16-hospital network (Viet Nam Resistance: VINARES) was established and consisted of national and provincial-level hospitals across the country. Antimicrobial susceptibility testing results from routine clinical diagnostic specimens and antibiotic consumption data in Defined Daily Dose per 1000 bed days (DDD/1000 patient-days) were prospectively collected and analysed between October 2012 and September 2013.

RESULTS

Data from a total of 24 732 de-duplicated clinical isolates were reported. The most common bacteria were: Escherichia coli (4437 isolates, 18%), Klebsiella spp. (3290 isolates, 13%) and Acinetobacter spp. (2895 isolates, 12%). The hospital average antibiotic consumption was 918 DDD/1000 patient-days. Third-generation cephalosporins were the most frequently used antibiotic class (223 DDD/1000 patient-days, 24%), followed by fluoroquinolones (151 DDD/1000 patient-days, 16%) and second-generation cephalosporins (112 DDD/1000 patient-days, 12%). Proportions of antibiotic resistance were high: 1098/1580 (69%) Staphylococcus aureus isolates were methicillin-resistant (MRSA); 115/344 isolates (33%) and 90/358 (25%) Streptococcus pneumoniae had reduced susceptibility to penicillin and ceftriaxone, respectively. A total of 180/2977 (6%) E. coli and 242/1526 (16%) Klebsiella pneumoniae were resistant to imipenem, respectively; 602/1826 (33%) Pseudomonas aeruginosa were resistant to ceftazidime and 578/1765 (33%) to imipenem. Of Acinetobacter spp. 1495/2138 (70%) were resistant to carbapenems and 2/333 (1%) to colistin.

CONCLUSIONS

These data are valuable in providing a baseline for AMR among common bacterial pathogens in Vietnamese hospitals and to assess the impact of interventions.

Non-clinical isolates as potential reservoirs of antibiotic resistance in Port Harcourt, Nigeria

Introduction

Multidrug resistance (MDR) is a growing problem worldwide. This type resistance often arises due to the sequential acquisition of drug resistance determinants and subsequent clonal spread. It is therefore important to determine possible reservoirs of these MDR gene to help set out control strategies. This study was aimed at analysing susceptibility patterns of various non-clinical Gram negative bacterial strains to determine their potential as reservoirs of MDR.

Methods

Thirty-five non-clinical Gram negative bacteria were identified and susceptibility profile determined using standard methodologies.

Results

Findings showed a preponderance of Pseudomonas aeruginosa and Escherichia Coli. Resistance rates of above 80% were noted in 50% of antibiotics, though none of the isolates were resistant to Ofloxacin. Majority of isolates (68.6%) had a multiple antibiotic resistance (MAR) index greater than 0.5, but only 20% of Escherichia Eoli. were found in this category. A high level of MDR was noted in this study (71.4%), but again only 20% of these were Escherichia Coli.

Conclusion

Gram negative bacteria are the most common group of bacteria frequently encountered in clinical microbiology. In more recent years, infections with these organisms have been further complicated by the phenomenon of drug resistance. Non-clinical isolates have been postulated as possible reservoirs. Findings from this study of widespread multidrug resistance support this idea. This study however highlights the lack of MDR in Escherichia Coli, which is promising. More extensive studies will need to be carried out to properly assess the role of non-clinical isolates as reservoirs of MDR determinants.

Susceptibility testing and reporting of new antibiotics with a focus on tedizolid: an international working group report

Inappropriate use and overuse of antibiotics are among the most important factors in resistance development, and effective antibiotic stewardship measures are needed to optimize outcomes. Selection of appropriate antimicrobials relies on accurate and timely antimicrobial susceptibility testing. However, the availability of clinical breakpoints and in vitro susceptibility testing often lags behind regulatory approval by several years for new antimicrobials. A Working Group of clinical/medical microbiologists from Brazil, Canada, Mexico, Saudi Arabia, Russia and the UK recently examined issues surrounding antimicrobial susceptibility testing for novel antibiotics. While commercially available tests are being developed, potential surrogate antibiotics may be used as marker of susceptibility. Using tedizolid as an example of a new antibiotic, this special report makes recommendations to optimize routine susceptibility reporting.

Encouraging rational antibiotic use in childhood pneumonia: a focus on Vietnam and the Western Pacific Region

Globally, pneumonia is considered to be the biggest killer of infants and young children (aged <5 years) outside the neonatal period, with the greatest disease burden in low- and middle-income countries. Optimal management of childhood pneumonia is challenging in settings where clinicians have limited information regarding the local pathogen and drug resistance profiles. This frequently results in unnecessary and poorly targeted antibiotic use. Restricting antibiotic use is a global priority, particularly in Asia and the Western Pacific Region where excessive use is driving high rates of antimicrobial resistance. The authors conducted a comprehensive literature review to explore the antibiotic resistance profile of bacteria associated with pneumonia in the Western Pacific Region, with a focus on Vietnam. Current management practices were also considered, along with the diagnostic dilemmas faced by doctors and other factors that increase unnecessary antibiotic use. This review offers some suggestions on how these issues may be addressed.

Results from the Survey of Antibiotic Resistance (SOAR) 2011-13 in the Gulf States

OBJECTIVES

To provide surveillance data on the susceptibility of community-acquired respiratory tract isolates from four Gulf and Near East countries from 2011 to 2013.

METHODS

MICs were determined using Etests(®) for all antibiotics evaluated except erythromycin, where testing was by disc diffusion. Susceptibility was assessed using CLSI, EUCAST and pharmacokinetic/pharmacodynamic (PK/PD) breakpoints.

RESULTS

Seven hundred and twenty-six respiratory isolates comprising 265 isolates of Streptococcus pneumoniae, 125 isolates of Streptococcus pyogenes and 336 isolates of Haemophilus influenzae were collected from Bahrain, Lebanon, Oman and the United Arab Emirates (UAE). Among S. pneumoniae, susceptibility to penicillin was low in the UAE and Bahrain. Macrolide susceptibility was ∼45%-60% in the UAE and Oman but higher in Lebanon (73.7%) and Bahrain (84%-85%). Penicillin susceptibility using CLSI intravenous breakpoints was >85% in all countries. Antibiotic susceptibility of S. pneumoniae was lower in UAE and Oman. Among S. pyogenes isolates, resistance to erythromycin was highest in Oman (31.6%) but <20% in the other countries. In H. influenzae, susceptibility to most antibiotics was high, except for ampicillin in Lebanon (70.2%) and amoxicillin in Oman (95.4%). Lebanon also had a high percentage (14.9%) of β-lactamase-positive isolates with non-susceptibility to ampicillin. Amoxicillin/clavulanic acid susceptibility was >95% in all countries. Use of EUCAST versus CLSI breakpoints demonstrated profound differences for cefaclor and cefuroxime in S. pneumoniae and H. influenzae, with EUCAST showing lower susceptibility.

CONCLUSIONS

There was considerable variability in susceptibility among countries in the same region. Thus, continued surveillance is necessary to track future changes in antibiotic resistance.

Results from the Survey of Antibiotic Resistance (SOAR) 2012-14 in Thailand, India, South Korea and Singapore

OBJECTIVES

To provide susceptibility data for community-acquired respiratory tract isolates of Streptococcus pneumoniae, Streptococcus pyogenes, Haemophilus influenzae and Moraxella catarrhalis collected in 2012-14 from four Asian countries.

METHODS

MICs were determined using Etest(®) for all antibiotics except erythromycin, which was evaluated by disc diffusion. Susceptibility was assessed using CLSI, EUCAST and pharmacokinetic/pharmacodynamic (PK/PD) breakpoints. For macrolide/clindamycin interpretation, breakpoints were adjusted for incubation in CO2 where available.

RESULTS

Susceptibility of S. pneumoniae was generally lower in South Korea than in other countries. Penicillin susceptibility assessed using CLSI oral or EUCAST breakpoints ranged from 21.2% in South Korea to 63.8% in Singapore. In contrast, susceptibility using CLSI intravenous breakpoints was much higher, at 79% in South Korea and ∼95% or higher elsewhere. Macrolide susceptibility was ∼20% in South Korea and ∼50%-60% elsewhere. Among S. pyogenes isolates (India only), erythromycin susceptibility (∼20%) was lowest of the antibiotics tested. In H. influenzae antibiotic susceptibility was high except for ampicillin, where susceptibility ranged from 16.7% in South Korea to 91.1% in India. South Korea also had a high percentage (18.1%) of β-lactamase-negative ampicillin-resistant isolates. Amoxicillin/clavulanic acid susceptibility for each pathogen (PK/PD high dose) was between 93% and 100% in all countries except for H. influenzae in South Korea (62.5%).

CONCLUSIONS

Use of EUCAST versus CLSI breakpoints had profound differences for cefaclor, cefuroxime and ofloxacin, with EUCAST showing lower susceptibility. There was considerable variability in susceptibility among countries in the same region. Thus, continued surveillance is necessary to track future changes in antibiotic resistance.