High burden of antimicrobial drug resistance in Asia

Epidemiology and outcomes of multidrug-resistant bacterial infection in non-cystic fibrosis bronchiectasis

PURPOSE

Multidrug-resistant (MDR) bacteria impose a considerable health-care burden and are associated with bronchiectasis exacerbation. This study investigated the clinical outcomes of adult patients with bronchiectasis following MDR bacterial infection.

METHODS

From the Chang Gung Research Database, we identified patients with bronchiectasis and MDR bacterial infection from 2008 to 2017. The control group comprised patients with bronchiectasis who did not have MDR bacterial infection and were propensity-score matched at a 1:2 ratio. The main outcomes were in-hospital and 3-year mortality.

RESULTS

In total, 554 patients with both bronchiectasis and MDR bacterial infection were identified. The types of MDR bacteria that most commonly affected the patients were MDR- Acinetobacter baumannii (38.6%) and methicillin-resistant Staphylococcus aureus (18.4%), Extended-spectrum-beta-lactamases (ESBL)- Klebsiella pneumoniae (17.8%), MDR-Pseudomonas (14.8%), and ESBL-E. coli (7.5%). Compared with the control group, the MDR group exhibited lower body mass index scores, higher rate of chronic bacterial colonization, a higher rate of previous exacerbations, and an increased use of antibiotics. Furthermore, the MDR group exhibited a higher rate of respiratory failure during hospitalization (MDR vs. control, 41.3% vs. 12.4%; p < 0.001). The MDR and control groups exhibited in-hospital mortality rates of 26.7% and 7.6%, respectively (p < 0.001); 3-year respiratory failure rates of 33.5% and 13.5%, respectively (p < 0.001); and 3-year mortality rates of 73.3% and 41.5%, respectively (p < 0.001). After adjustments were made for confounding factors, the infection with MDR and MDR bacteria species were determined to be independent risk factors affecting in-hospital and 3-year mortality.

CONCLUSIONS

MDR bacteria were discovered in patients with more severe bronchiectasis and were independently associated with an increased risk of in-hospital and 3-year mortality. Given our findings, we recommend that clinicians identify patients at risk of MDR bacterial infection and follow the principle of antimicrobial stewardship to prevent the emergence of resistant bacteria among patients with bronchiectasis.

Epidemiology of extended-spectrum β-lactamases in Enterobacterales in Taiwan for over two decades

The emergence of antimicrobial resistance among microorganisms is a serious public health concern, and extended-spectrum β-lactamases (ESBL)-producing Enterobacterales is one of the major concerns among antibiotic-resistant bacteria. Although the prevalence of ESBL in Enterobacterales has been increasing with time, the prevalence of ESBL could differ according to the species, hospital allocation, sources of infections, nosocomial or community acquisitions, and geographic regions. Therefore, we conducted a comprehensive review of the epidemiology of ESBL-producing Enterobacterales in Taiwan. Overall, the rates of ESBL producers are higher in northern regions than in other parts of Taiwan. In addition, the genotypes of ESBL vary according to different Enterobacterales. SHV-type ESBLs (SHV-5 and SHV-12) were the major types of Enterobacter cloacae complex, but Serratia marcescens, Proteus mirabilis, Escherichia coli, and Klebsiella pneumoniae were more likely to possess CTX-M-type ESBLs (CTX-M-3 and CTX-M-14). Moreover, a clonal sequence type of O25b-ST131 has been emerging among urinary or bloodstream E. coli isolates in the community in Taiwan, and this clone was potentially associated with virulence, ESBL (CTX-M-15) production, ciprofloxacin resistance, and mortality. Finally, the evolution of the genetic traits of the ESBL-producing Enterobacterales isolates helps us confirm the interhospital and intrahospital clonal dissemination in several regions of Taiwan. In conclusion, continuous surveillance in the investigation of ESBL production among Enterobacterales is needed to establish its long-term epidemiology.

Gaps in antimicrobial stewardship programmes in Asia: a survey of 10 countries

OBJECTIVES

To determine antimicrobial stewardship (AMS) programme practices in Asian secondary- and tertiary-care hospitals.

METHODS

AMS programme team members within 349 hospitals from 10 countries (Cambodia, India, Indonesia, Japan, Malaysia, Pakistan, the Philippines, Taiwan, Thailand and Vietnam) completed a questionnaire via a web-based survey link. The survey contained questions as to whether 12 core components deemed essential for AMS programmes were implemented.

RESULTS

Overall, 47 (13.5%) hospitals fulfilled all core AMS programme components. There was a mean positive response rate (PRR) of 85.6% for the responding countries in relation to a formal hospital leadership statement of support for AMS activities, but this was not matched by budgeted financial support for AMS activities (mean PRR 57.1%). Mean PRRs were ≥80.0% for the core AMS team comprising a physician or other leader responsible for AMS activities, a pharmacist and infection control and microbiology personnel. Most hospitals had access to a timely and reliable microbiology service (mean PRR 90.4%). Facility-specific antibiotic treatment guidelines for common infections (mean PRR 78.7%) were in place more often than pre-authorization and/or prospective audit and feedback systems (mean PRR 66.5%). In terms of AMS monitoring and reporting, PRRs of monitoring specific antibiotic use, regularly publishing AMS outcome measures, and the existence of a hospital antibiogram were 75.1%, 64.4% and 77.9%, respectively.

CONCLUSIONS

Most hospitals participating in this survey did not have AMS programmes fulfilling the requirements for gold standard AMS programmes in hospital settings. Urgent action is required to address AMS funding and resourcing deficits.

The Incidence of Extended Spectrum β-Lactamase Enzymes and Their Connection to Virulence Genes in Community-Acquired Urinary Tract Infection

In community-acquired urinary tract infections, Klebsiella pneumoniae is considered one of the most common etiological agents. Multidrug resistance and virulence are common in Klebsiella pneumoniae populations. In this study, fifty Klebsiella pneumoniae isolates were isolated from urine samples and identified using a vitek 2 compact device. The Kirby–Bauer disk diffusion technique used the antibiotic susceptibility test. According to the findings, approximately [n = 46 (92%)] of Klebsiella pneumoniae isolates are multidrug-resistant (MDR). To detect the production of Extended Spectrum β-lactamase (ESBL) enzymes, the Modified Double Disc Synergy Test (MDDST) was used. The results show that approximately [n=45 (90%)] of the isolates produce ESBLs. The most common ESBL genes (TEM, SHV, and CTX-M) were investigated in isolates. The results show that the SHV gene had the highest prevalence among ESBL genes [n = 34 (68%)], followed by the CTX-M gene [n = 33 (66%)]. while none of the isolates possessed the TEM gene. The virulence factor type 3 fimbriae (MrKD) gene and biofilm (BssS) gene were revealed. The results found that the isolates contain the MrKD gene at [n = 41 (82%)]. At the same time, the results found that the isolates contained the BssS gene at [n =36 (72%)]. The prevalence of Virulence genes within ESBL-producing Klebsiella pneumoniae isolates shows that only [n = 3 (6%)] of isolates that are non-ESBL producers carry one or both virulence genes, while [n=41 (82%)] of ESBL-producing isolates contain one or both virulence genes. The prevalence of ESBL-producing Klebsiella pneumoniae in community patients was high in this research. There may also be a correlation between ESBL production and some virulence factors. Keywords. Klebsiella pneumoniae; Antibiotic Resistance; Virulence Gene; ESBL; Urinary Tract Infection; CTX-M.

Socio-Demographic Factors Associated with Antibiotics and Antibiotic Resistance Knowledge and Practices in Vietnam: A Cross-Sectional Survey

(1) Background: Antibiotic resistance (ABR) has been escalating to seriously high levels worldwide, accelerated by the misuse and overuse of antibiotics, especially in Vietnam. In this work, we investigated the Vietnamese public socio-demographic and knowledge factors associated with inappropriate practices of antibiotics to better understand the country’s antibiotic use and ABR. (2) Methods: To this end, a cross-sectional survey was conducted among Vietnamese people aged 18−60 years via Computer Assisted Telephone Interviews (CATIs) from May 2019 to November 2019. (3) Results: Among 3069 responses distributed equally in all 63 provinces in Vietnam, 1306 respondents completed the survey (response rate of 42.5%). Socio-demographically, most participants were male (56.4%), 18−25 years old (40.4%), located in Southern Vietnam (67.1%), highly educated (93.7%), and possessed medical insurance (95.3%). Respondents with higher education levels (college and above) had 2.663 times higher knowledge scores than those with lower education levels (p < 0.001). High-income respondents possessed more knowledge than low-income respondents (OR = 1.555, CI 95% 0.835−2.910, p = 0.024). Students, non-skilled workers, skilled workers, and professionals and managers had 0.052, 0.150, 0.732, and 0.393 times lower practice scores than the unemployed group, respectively (p < 0.001). Furthermore, respondents with higher/adequate knowledge scores had higher practice scores than those with inadequate knowledge scores (p < 0.05). (4) Conclusions: The findings indicate that socio-demographic differences in knowledge and practices exist, and focusing on these issues should be the priority in forthcoming interventions. The research data also provide information for policy makers to raise the community’s awareness of ABR.

Development of novel effective agents from 1H-indolylammonium trifluoroacetates effective against conditionally pathogenic microorganisms

Introduction: The problem of antibiotic resistance of microorganisms is becoming more urgent in the twenty-first century. More and more pathogenic microbes are becoming resistant to two or more antibiotics. This problem has become worse into the COVID-19 pandemic. The search for new compounds with antimicrobial activity is one of the principles for overcoming the antibiotic resistance of microorganisms.

Materials and methods: Methods for the preparation, isolation, and identification of salts of 2,3,5-trimethyl-, 1,2,3,5-tetramethyl-, 2,3-dimethyl-5-methoxy-, 5-methoxy-1,2,3-trimethyl-1H-indole-6-amines and trifluoroacetic acid were developed and laboratory microbiological studies of them for antimicrobial activity were carried out. Sensitivity of the test-strains of microorganisms to the new compounds was studied. A method of serial dilutions to determine the minimal inhibitory concentration (MIC) of the compounds under study was used in the study.

Results and discussion: The compounds 5–8 showed a pronounced antibacterial activity against the test strains of microorganisms in vitro with MIC from 0.98 µg/mL to 125.0 µg/mL. The prospects for targeted synthesis of biologically active compounds which are derivatives of 1H-indolylamines with a trifluoromethyl group in the molecule were determined, and after additional studies, the compounds 5–8 may find application as water-soluble synthetic antimicrobial agents.

Conclusion: The laboratory microbiological screening of showed that they have an antimicrobial effect that exceeds the activity of the reference drug, dioxidine. The presence of molecular mechanisms predicted in silico in the spectrum of biological activity of the studied compounds, such as Pseudolysin inhibitor, Omptin inhibitor, Undecaprenyldiphospho-muramoylpentapeptide beta-N-acetylglucosaminyltransferase inhibitor, UDP-epimerase inhibitor, Bacterial efflux pump inhibitor, suggests the presence of antimicrobial activity against gram-positive and gram-negative microorganisms. Trifluoroacetates 2,3,5-trimethyl-1H-indole-6-ammonium (5), 1,2,3,5-tetramethyl-1H-indole-6-ammonium (6), 2,3-dimethyl-5-methoxy-1H-indole-6-ammonium (7), 1,2,3-trimethyl-5-methoxy-1H-indole-6-ammonium (8), after additional studies, may find application as water-soluble synthetic antimicrobial agents.

Antibacterial effects of nano-decoction iron polysulfide in epididymitis and the systematic evaluation of its toxicity on the reproductive health of male mice

Ferrous iron and polysulfide (Fe(II)S_n aq) is a nano-decoction. It is usually prepared from the suspension of iron sulfide nanomaterial, using autoclave and centrifugation. A previous study conducted in our laboratory revealed that Fe(II)S_n aq was highly antibacterial, and it could efficiently kill more than 90% population of Escherichia coli and Staphylococcus aureus, within 5 min of the treatment. Our study reported that the intravenous administration of Fe(II)S_n aq provided effective treatment against epididymis infection, caused by S. aureus. The results of the study further highlighted its potential for clinical application. However, its effects on the reproductive system and overall health of mammals have not been investigated earlier. The present study assessed the impacts of Fe(II)S_n aq on reproductive health and other aspects of male mice. Briefly, male mice were exposed to Fe(II)S_n aq, either intravenously at the dose of 0.7 mM, 1.4 mM, and 2.8 mM of Fe²⁺or orally at the dose of 1.4 mM, 2.8 mM, and 5.6 mM of Fe²⁺. Following this, body weight, organs index, quality of sperm, blood biochemical markers, histopathology of organs, oxidative stress and apoptosis were evaluated, after 1 day and 30 days of exposure. In addition, male reproductivity was evaluated in terms of mating with female mice, and the body weight of the resulting offspring was recorded. Our results showed that the mice processed with Fe(II)S_n aq exhibited normal physiological status and reproductive capability. The present study illustrated the short- and long-term influences of Fe(II)S_n aq on the fertility of male mice for the first time. The findings of the study provided a valuable reference for the application of Fe(II)S_n aq, particularly in terms of reproductive safety.

Analysis of the upstream genetic structures of the ISEcp1-blaCTX-M transposition units in Escherichia coli isolates carrying blaCTX-M obtained from the Indonesian and Vietnamese communities

Extended spectrum β-lactamase (ESBL)-producing Escherichia coli have been found in healthy individuals in Indonesia and Vietnam. The ISEcp1-bla_CTX-M transposition unit of ESBL-producing bacterial isolates has been considered responsible for the production of CTX-M type ESBL and it is important for the dissemination of bla_CTX-M . This study aimed to characterize the upstream genetic structure (UGS) of E. coli isolates possessing bla_CTX-M-1 group and/or bla_CTX-M-9 group genes obtained from healthy individuals in Indonesia and Vietnam. A total of 501 CTX-M type ESBL-producing E. coli isolates possessing bla_CTX-M-1 group and/or bla_CTX-M-9 group genes were obtained from healthy individuals of the two countries in 2018. The UGSs of the ISEcp1-bla_CTX-M transposition unit of the 501 ESBL-producing E. coli isolates were amplified by barcode-adaptor-ligation-mediated PCR and analyzed using the Nanopore sequencer. The obtained sequence information was used to classify the UGSs of the ISEcp1-bla_CTX-M transposition unit. From the 501 ESBL-producing E. coli isolates, 502 UGSs were obtained, which were classified into 85 UGS types based on the sequence. ISEcp1 of 359 (71.5%) of the 502 UGSs was disrupted by gene insertion, and ISEcp1-bla_CTX-M transposition unit of most (87.1%) of the determined UGSs was confirmed as plasmidic. Only 6 (7.1%) of the 85 UGS types were common to both countries. Our results indicated that many different UGSs of ISEcp1-bla_CTX-M transposition units were detected in Indonesia and Vietnam; hence, we suggest that structurally different kinds of plasmids harboring bla_CTX-M were separately distributed in the two countries.

Coexistence of aminoglycoside resistance genes in CTX-M-producing isolates of Klebsiella pneumoniae in Bushehr province, Iran

Background and Objectives:

Increasing the rate of extended-spectrum β-lactamase (ESBL)-producing Klebsiella pneumoniae has given rise to a major healthcare issue in clinical settings over the past few years. Treatment of these strains is hardly effective since the plasmid encoding ESBL may also carry other resistance genes including aminoglycosides. The current study aimed to evaluate the prevalence of ESBL-producing K. pneumoniae and investigate the coexistence of Cefoxitamase-Munich (bla_CTX-M) with aminoglycoside-modifying enzyme (AME) genes, aac(3)IIa as well as aac(6′)Ib, in CTX-M-producing K. pneumoniae isolated from patients in Bushehr province, Iran.

Materials and Methods:

A total of 212 K. pneumoniae isolates were collected and confirmed using polymerase chain reaction (PCR) of the malate dehydrogenase gene. Isolates were screened for production of ESBL. Phenotypic confirmatory test was performed using combined disk test. The genes encoding CTX-M groups and AME genes, aac(3)IIa and aac(6′)Ib, were investigated by PCR.

Results:

The ESBL phenotype was detected in 56 (26.4%) K. pneumoniae isolates. Moreover, 83.9% of ESBL-producing isolates carried the genes for CTX-M type β-lactamases, which were distributed into the two genetic groups of CTX-M-1 (97.8%)- and CTX-M-2 (2.1%)-related enzymes. Notably, among K. pneumoniae isolates containing the bla_CTX-M gene, 68.08% of isolates harbored AME genes. In addition, the coexistence of bla_CTX-M with aac(3)-IIa and aac(6′)-Ib was observed in 46.8% of CTX-M-producing K. pneumoniae isolates.

Conclusion:

This study provides evidence of a high prevalence of AME genes in CTX-M-producing K. pneumoniae isolates; therefore, in the initial empirical treatment of infections caused by ESBL-KP in regions with such antibiotic resistance patterns, aminoglycoside combination therapy should be undertaken carefully.

Multicenter surveillance of antimicrobial susceptibilities and resistance mechanisms among Enterobacterales species and non-fermenting Gram-negative bacteria from different infection sources in Taiwan from 2016 to 2018

OBJECTIVES

To explore the in vitro antimicrobial susceptibility among clinically important Gram-negative bacteria (GNB) in Taiwan.

METHODS

From 2016 through 2018, a total of 5458 GNB isolates, including Escherichia coli (n = 1545), Klebsiella pneumoniae (n = 1255), Enterobacter species (n = 259), Pseudomonas aeruginosa (n = 1127), Acinetobacter baumannii complex (n = 368), and Stenotrophomonas maltophilia (n = 179), were collected. The susceptibility results were summarized by the breakpoints of minimum inhibitory concentration (MIC) of CLSI 2020, EUCAST 2020 (for colistin), or published articles (for ceftolozane/tazobactam). The resistance genes among multidrug-resistant (MDR) or extensively drug-resistant (XDR)-GNB were investigated by multiplex PCR.

RESULTS

Significantly higher rates of non-susceptibility (NS) to ertapenem and carbapenemase production, predominantly KPC and OXA-48-like beta-lactamase, were observed in Enterobacterales isolates causing respiratory tract infection than those causing complicated urinary tract or intra-abdominal infection (12.7%/3.44% vs. 5.7%/0.76% or 7.7%/0.97%, respectively). Isolates of Enterobacter species showed higher rates of phenotypic extended-spectrum β-lactamase and NS to ertapenem than E. coli or K. pneumoniae isolates. Although moderate activity (54-83%) was observed against most potential AmpC-producing Enterobacterales isolates, ceftolozane/tazobactam exhibited poor in vitro (44.7-47.4%) activity against phenotypic AmpC Enterobacter cloacae isolates. Additionally, 251 (22.3%) P. aeruginosa isolates exhibited the carbapenem-NS phenotype, and their MDR and XDR rate was 63.3% and 33.5%, respectively. Fifteen (75%) of twenty Burkholderia cenocepacia complex isolates were inhibited by ceftolozane/tazobactam at MICs of ≤4 μg/mL.

CONCLUSIONS

With the increase in antibiotic resistance in Taiwan, it is imperative to periodically monitor the susceptibility profiles of clinically important GNB.

Exploring the Antibiotic Resistance Burden in Livestock, Livestock Handlers and Their Non-Livestock Handling Contacts: A One Health Perspective

Antibiotics are freqeuently used in the livestock sector in low- and middle-income countries for treatment, prophylaxis, and growth promotion. However, there is limited information into the zoonotic prevalence and dissemination patterns of antimicrobial resistance (AMR) within these environments. In this study we used pig farming in Thailand as a model to explore AMR; 156 pig farms were included, comprising of small-sized (<50 sows) and medium-sized (≥100 sows) farms, where bacterial isolates were selectively cultured from animal rectal and human fecal samples. Bacterial isolates were subjected to antimicrobial susceptibility testing (AST), and whole-genome sequencing. Our results indicate extensive zoonotic sharing of antibiotic resistance genes (ARGs) by horizontal gene transfer. Resistance to multiple antibiotics was observed with higher prevalence in medium-scale farms. Zoonotic transmission of colistin resistance in small-scale farms had a dissemination gradient from pigs to handlers to non-livestock contacts. We highly recommend reducing the antimicrobial use in animals’ feeds and medications, especially the last resort drug colistin.

Co-infections of two carbapenemase-producing Enterobacter hormaechei clinical strains isolated from the same diabetes individual in China

Introduction. Since mcr-1 was first reported in China, there have been ten variants of MCR appearing nationwide so far. Multidrug-resistant Enterobacteriaceae bacteria carrying both NDM and MCR have become a serious threat to global public health.Hypothesis/Gap Statement. The genetic structure of mcr-9 needs to be better understood in order to better prevent and control the transmission of drug-resistant genes.Aims. The aim of this study was to characterize the presence of two Enterobacter hormaechei isolates, which carries bla _NDM-5 CME2 and the coexistence of mcr-9 and bla _NDM-1 strain CMD2, which were isolated from a patient with diabetes in Sichuan, China.Methodology. The microbroth dilution method was used for antibiotic susceptibility. Conjugation experiment was used to investigate the transferability of bla _NDM-1, bla _NDM-5 and mcr-9. Whole-genome sequencing was performed on Illumina HiSeq platform. The ability of biofilm formation was detected by crystal-violet staining, the virulence of the bacteria was measured by Galleria mellonella killing assay.Results. bla _NDM-5 carrier CME2 and CMD2 with bla _NDM-1 and mcr-9 were resistant to carbapenems, β-lactam, aminoglycoside, quinolone and tetracycline, while CMD2 was also resistant to colistin. Conjugation assay and plasmid replicon typing further demonstrated that both bla _NDM-1 and bla _NDM-5 were respectively present on the self-transferrable IncX3 plasmid, mcr-9 was located on the self-transferrable IncHI2 plasmid. Through the analysis of mcr-9 gene context, the structure was DUF4942-rcnR-rcnA-copS-IS903-mcr-9-wbuC-qseC-qseB-IS1R-ΔsilR-IS903, bla _NDM-1 context was IS3000-ΔISAba125-IS5-bla _NDM-1-ble-trpF-groS-groL-insE-ΔIS26 structure, bla _NDM-5 structure was IS3000-bla _NDM-5-ble-trpF-dsbC-ΔIS26-umuD-ISKox3-tnpR-parA. Biofilm formation of CME2 was stronger than CMD2. There was no significant difference in virulence between the two strains.Conclusion. This study reveals two multiple drug-resistant E. hormaechei isolates from diabetes patient samples. E. hormaechei carrying two NDM-resistant genes is already a serious threat, where MCR is an important cause of treatment failure in bacterial infections. This study is a reminder not only to prevent infection in patients with diabetes, but also to constantly monitor the epidemic and spread of the drug-resistant gene.

Gram-Negative Bacteria Isolates and Their Antibiotic-Resistance Patterns in Patients with Wound Infection in Ethiopia: A Systematic Review and Meta-Analysis

BACKGROUND

Antibiotic resistance (ABR) restricts the armamentarium of health-care providers against infectious diseases due to the emergence of multidrug resistance (MDR), especially in Gram-negative bacteria. This study aimed to determine pooled estimates of Gram-negative bacteria, their resistance profiles, and rates of MDR in patients with wound infection in Ethiopia.

METHODS

Electronic databases such as PubMed/MEDLINE, EMBASE, Science Direct, Web of Science, and Google Scholar were searched. Original articles, available online from 1988 to 2020, addressing the prevalence and resistance patterns of Gram-negative bacteria in patients with wound infection and written in English were screened. The data were extracted using a format prepared in Microsoft Excel and exported to STATA 14.0 for the outcome analyses.

RESULTS

The data of 15,647 wound samples, from 36 studies conducted in 5 regions of the country, were pooled. The overall pooled estimate of Gram-negative bacteria was 59% [95% CI: 52-65%, I2 = 96.41%, p < 0.001]. The pooled estimate of Escherichia colirecovered from isolates of 5205 wound samples was 17% [95% CI: 14-20%], followed by Pseudomonas aeruginosa, 11% [95% CI: 9-14%], Klebsiella pneumonia, 11% [95% CI: 9-13%], Proteus mirabilis, 8% [95% CI: 6-10%], Acinetobacter species, 4% [95% CI: 2-6%], Enterobacter species, 4% [95% CI: 3-5%], and Citrobacter species, 3% [95% CI: 2-4%]. Multidrug resistance prevalence estimates of E. coli, K. pneumonia, P. aeruginosa, P. mirabilis, Citrobacter species, Enterobacter species and Acinetobacter species were 76% [95% CI: 66-86%], 84% [95% CI: 78-91%], 66% [95% CI:43-88%], 83% [95% CI:75-91%], 87% [95% CI:78-96%], 68% [95% CI:50-87%] and 71% [95% CI:46-96%], respectively.

CONCLUSION

There was high resistance in Gram-negative bacteria from wound specimens to commonly used antibiotics in Ethiopia. The data warrant the need of regular epidemiological surveillance of antimicrobial resistance and implementation of an efficient infection control program.

Microbiological profiles and antimicrobial resistance patterns of pediatric bloodstream pathogens in China, 2016-2018

OBJECTIVES

This study aimed to investigate the microbiological profiles and antimicrobial resistance patterns of bloodstream pathogens in Chinese children.

METHODS

This retrospective study was conducted at 13 tertiary hospitals in China during 2016-2018. The first bloodstream isolates of the same species from one pediatric patient < 18 years were included to this study for analysis. Antimicrobial susceptibility testing was determined based on minimum inhibitory concentrations or Kirby-Bauer disk diffusion methods according to the 2018 Clinical and Laboratory Standards Institute guidelines.

RESULTS

Overall, 9345 nonduplicate bloodstream isolates were collected. Top 10 pathogens included Coagulase-negative staphylococcus (CoNS) (44.4%), Escherichia coli (10.2%), Klebsiella pneumoniae (5.9%), Staphylococcus aureus (5.0%), Streptococcus pneumoniae (4.9%), Pseudomonas aeruginosa(2.8%), Enterococcus faecium (2.7%), Stenotrophomonas maltophilia (2.4%), Salmonella spp. (2.3%), and Streptococcus agalactiae (2.0%). The commonest pathogens apart from CoNS in age group 0-28 days, 29 days-2 months, 3-11 months, 1-5 years, and ≥ 5 years were Escherichia coli (17.2%), Escherichia coli (14.0%), Escherichia coli (7.9%), Streptococcus pneumoniae (10.7%) ,and Staphylococcus aureus (13.6%), respectively. The overall prevalence of extended-spectrum β-lactamases-producing Enterobacteriaceae, carbapenem-resistant Klebsiella pneumoniae, carbapenem-resistant Acinetobacter baumannii, and carbapenem-resistant Pseudomonas aeruginosa were 41.4, 28.4, 31.7, and 5.6%, respectively. The overall prevalence of methicillin-resistant Staphylococcus aureus, penicillin-resistant Streptococcus pneumoniae and vancomycin-resistant Enterococcus was 38.1, 28.3, and 0.7%, respectively.

CONCLUSIONS

The major bacterial pathogens have differences in different age groups, ward types, and regions in Chinese children, and the commonest causing microorganism was the Escherichia coli, especially in neonates and infants. High prevalence of important resistant phenotypes is of a serious concern.

Novel Nanotherapeutics as Next-generation Anti-infective Agents: Current Trends and Future Prospectives

With the ever-increasing population and improvement in the healthcare system in the 21st century, the incidence of chronic microbial infections and associated health disorders has also increased at a striking pace. The ability of pathogenic microorganisms to form biofilm matrix aggravates the situation due to antibiotic resistance phenomenon resulting in resistance against conventional antibiotic therapy which has become a public health concern. The canonical Quorum Sensing (QS) signaling system hierarchically regulates the expression of an array of virulence phenotypes and controls the development of biofilm dynamics. It is imperative to develop an alternative, yet effective and non-conventional therapeutic approach, popularly known as "anti-infective therapy" which seems to be interesting. In this regard, targeting microbial QS associated virulence and biofilm development proves to be a quite astonishing approach in counteracting the paucity of traditional antibiotics. A number of synthetic and natural compounds are exploited for their efficacy in combating QS associated microbial infections but the bioavailability and biocompatibility limit their widespread applications. In this context, the nanotechnological intervention offers a new paradigm for widespread biomedical applications starting from targeted drug delivery to diagnostics for the diagnosis and treatment of infectious diseases, particularly to fight against microbial infections and antibiotics resistance in biofilms. A wide range of nanomaterials ranging from metallic nanoparticles to polymeric nanoparticles and recent advances in the development of carbon-based nanomaterials such as Carbon Nanotubes (CNTs), Graphene Oxide (GO) also immensely exhibited intrinsic antiinfective properties when targeted towards microbial infections and associated MDR phenomenon. In addition, the use of nano-based platforms as carriers emphatically increases the efficacy of targeted and sitespecific delivery of potential drug candidates for preventing microbial infections.

Research note: Occurrence of mcr-encoded colistin resistance in Escherichia coli from pigs and pig farm workers in Vietnam

WHO considers colistin as a highest priority critically important drug for human health, and occurrence of colistin-resistant bacteria in livestock is of health concern. The current study determined occurrence of colistin-resistant Escherichia coli in pigs and workers at pig farms in Vietnam, and investigated the genetic background for resistance. Colistin-resistant E. coli were detected from pigs in 53/116 (45.7%) farms, and from workers taking care of the pigs in 21/94 (22.3%) farms. Colistin-resistant isolates showed MIC to colistin between 4-16 mg/L, they were multidrug resistant (99%) and resistance was caused by the presence of mcr-1 genes in 97/102 (95.1%) E. coli from pigs and in 31/34 (91.1%) isolates from humans. mcr-1 is considered a plasmid-encoded gene, but this was not confirmed in the current investigation. In total, one pig isolate carried both mcr-1 and mcr-3 genes, whereas mcr-2, mcr-4 and mcr-5 genes were not detected. Shared resistance profiles between pig and human isolates on the same farm was only observed in four farms. The study showed that commensal E. coli from pigs in Vietnam constitute a reservoir for colistin-resitant E. coli, however, further studies are needed to confirm that mcr genes are associated with plasmids and their importance for human health.

Gonococcal resistance can be viewed productively as part of a syndemic of antimicrobial resistance: an ecological analysis of 30 European countries

BACKGROUND

It is unclear how important bystander selection is in the genesis of antimicrobial resistance (AMR) in Neisseria gonorrhoeae.

METHODS

We assessed bystander selection in a novel way. Mixed-effects linear regression was used to assess if country-level prevalence of gonococcal AMR in 30 European countries predicts homologous AMR in other bacteria. The data used was from the European Antimicrobial Resistance Surveillance Network.

RESULTS

The prevalence of gonococcal ciprofloxacin resistance was found to be positively associated with AMR prevalence in E. coli (coef. 0.52; P = 0.007), Acinetobacter spp. (coef. 0.13; P = 0.044) and Pseudomonas aeruginosa (coef. 0.36; P = 0.020) but not Klebsiella pneumoniae. Azithromycin resistance in N. gonorrhoeae was positively associated with macrolide resistance in Streptococcus pneumoniae (coef. 0.01; P = 0.018). No association was found for cephalosporins.

CONCLUSIONS

Gonococcal AMR is linked to that in other bacteria. This finding is likely explained by high antimicrobial consumption in affected populations and provides additional motivation for strengthening antimicrobial stewardship programs.

Colonization With Multidrug-Resistant Organisms Among Healthy Adults in the Community Setting: Prevalence, Risk Factors, and Composition of Gut Microbiome

BACKGROUND

The prevalence of colonization with multidrug-resistant organisms (MDROs) among healthy adults in the community is largely unknown. This study investigated the colonization rate of multidrug-resistant Enterobacteriaceae, methicillin-resistant Staphylococcus aureus (MRSA), and vancomycin-resistant enterococci (VRE) in the community in Taiwan, and compared the gut microbiota between MDRO carriers and non-carriers.

METHODS

This prospective cohort study was conducted from March 2017 to February 2018 at the Hsin-Chu and Jin-Shan branches of National Taiwan University Hospital. Nasal swabs and stool samples were obtained from healthy adults attending a health examination to screen for MDROs. Bacteria isolates of MDROs were tested for antibiotic susceptibility and resistant genes. Relevant data were collected using a standardized questionnaire to evaluate the risk factors for MDROs carriage, and 16S rRNA metagenomics sequencing was performed to analyze gut microbiota.

RESULTS

Among 187 participants, 4.6% (8/174) carried MRSA and 41.4% (77/186) carried third-generation cephalosporin-resistant (3GC-R) Escherichia coli or Klebsiella pneumoniae. The carriage rate of AmpC beta-lactamases and ESBL-producing strains were 16.1 and 27.4%, respectively. No carbapenem-resistant Enterobacteriaceae (CRE) or VRE were detected. The dominant resistant gene of E. coli isolates was CTX-M-type (73%), while that of K. pneumoniae was AmpC beta-lactamases (80%). In the multivariate analysis, the significant risk factors for carrying 3GC-R E. coli or K. pneumoniae were being an employee of technology company A [adjusted odds ratio (aOR) 4.127; 95% confidence interval (CI) 1.824-9.336; p = 0.001], and traveling to Southeast Asia in the past year (aOR 6.545; 95% CI 1.071-40.001; p = 0.042). The gut microbiota analysis showed that the phylum Proteobacteria and the family Enterobacteriaceae were significantly more abundant in 3GC-R E. coli and K. pneumoniae carriers.

CONCLUSION

A high rate of Taiwanese adults in the community carried 3GC-R Enterobacteriaceae, while no CRE or VRE colonization was noted. Compared with non-carriers, an expansion of Enterobacteriaceae in gut microbiota was found among 3GC-R Enterobacteriaceae carriers.

Clinical Relevance and Antimicrobial Profiling of Methicillin-Resistant Staphylococcus aureus (MRSA) on Routine Antibiotics and Ethanol Extract of Mango Kernel (Mangifera indica L.)

Methicillin-resistant Staphylococcus aureus (MRSA) is known for serious health problems. Testing new inexpensive natural products such as mango kernel (Mangifera indica L., Anacardiaceae) may provide alternative and economically viable anti-MRSA drugs. In the current study, we screened clinical isolates from Aseer Central Hospital, Saudi Arabia, during 2012–2017 for MRSA and tested an ethanolic extract of mango kernel for anti-MRSA activity. Brief confirmation of MRSA was performed by the Vitek 2 system, while antibiotic sensitivity of strains was tested for their clinical relevance. The In vitro disc diffusion method was used to test the anti-MRSA activity of the ethanolic mango kernel extract. The antimicrobial activity of mango kernel was compared to that of standard drugs (oxacillin and vancomycin). Of the identified 132 S. aureus strains, 42 (31.8%) were found to be MRSA and their prevalence showed a clear increase during the last two years (2016-2017; p < 0.001). MRSA strains showed 100% sensitivity to vancomycin, teicoplanin, linezolid, tetracycline, daptomycin, tigecycline, and tobramycin and 100% resistance to ampicillin and 98% to penicillin. The ethanolic extracts of mango kernel were found active against both S. aureus and the MRSA strains. Inhibitory activities (mean ± SE) were achieved at concentrations of 50 mg/mL (20.77 ± 0.61), 5 mg/mL (16.18 ± 0.34), and 0.5 mg/mL (8.39 ± 0.33) exceeding that of vancomycin (p=0.0162). MRSA strains were sensitive to mango kernel extracts when compared to vancomycin. Therefore, ethanolic extracts of mango kernel can be escalated to animal model studies as a promising leading anti-MRSA drug candidate and can be an economic alternative to high-priced synthetic antibiotics.

Antimicrobial Resistance in the Asia Pacific region: a meeting report

The Asia Pacific region, home to two-thirds of the world's population and ten of the least developed countries, is considered a regional hot-spot for the emergence and spread of antimicrobial resistance (AMR). Despite this, there is a dearth of high-quality regional data on the extent of AMR. Recognising the urgency to close this gap, Singapore organised a meeting to discuss the problems in the region and frame a call for action. Representatives from across the region and beyond attended the meeting on the "Antimicrobial Resistance in the Asia Pacific & its impact on Singapore" held in November 2018. This meeting report is a summary of the discussions on the challenges and progress in surveillance, drivers and levers of AMR emergence, and the promising innovations and technologies that could be used to combat the increasing threat of AMR in the region. Enhanced surveillance and research to provide improved evidence-based strategies and policies are needed. The major themes that emerged for an action plan are working towards a tailored solution for the region by harnessing the One Health approach, enhancing inter-country collaborations, and collaboratively leverage upon new emerging technologies. A regionally coordinated effort that is target-driven, sustainable and builds on a framework facilitating communication and governance will strengthen the fight against AMR in the Asia Pacific region.

Multi-Faceted Intervention to Improve the Antibiotic Prescriptions among Doctors for Acute URI and Acute Diarrhoea Cases: The Green Zone Antibiotic Project

Background

Antimicrobial resistance is a global problem that is perpetuated by the inappropriate use of antibiotics among doctors. This study aims to assess the antibiotic prescription rate for patients with acute upper respiratory infection (URI) and acute diarrhoea.

Methods

A completed clinical audit cycle was conducted in 2018 in the busy emergency department of a public hospital in Malaysia. Pre- and post-intervention antibiotic prescription data were collected, and changes were implemented through a multifaceted intervention similar to Thailand’s Antibiotics Smart Use programme.

Results

Data from a total of 1,334 pre-intervention and 1,196 post-intervention patients were collected from the hospital’s electronic medical records. The mean (SD) age of participants was 19.88 (17.994) years. The pre-intervention antibiotic prescription rate was 11.2% for acute diarrhoea and 29.1% for acute URI, both of which are above the average national rates. These antibiotic prescription rates significantly reduced post-intervention to 6.2% and 13.7%, respectively, falling below national averages. Antibiotic prescription rate was highest for young children. There were no significant changes in rates of re-attendance or hospital admission following the intervention.

Conclusion

The multifaceted intervention, which included continuing medical education, physician reminders and patient awareness, was effective in improving the antibiotic prescription rates for these two conditions.

In vitro activities of cefiderocol, ceftolozane/tazobactam, ceftazidime/avibactam and other comparative drugs against imipenem-resistant Pseudomonas aeruginosa and Acinetobacter baumannii, and Stenotrophomonas maltophilia, all associated with bloodstream infections in Taiwan

Objectives

We investigated the in vitro activities of cefiderocol, ceftazidime/avibactam, ceftolozane/tazobactam and other related drugs against imipenem-resistant Pseudomonas aeruginosa, imipenem-resistant Acinetobacter baumannii and Stenotrophomonas maltophilia isolates.

Methods

Non-duplicated bacteraemia isolates (n = 300) of imipenem-resistant P. aeruginosa (n = 100), imipenem-resistant A. baumannii (n = 100) and S. maltophilia (n = 100) were evaluated. Imipenem-resistant P. aeruginosa and imipenem-resistant A. baumannii isolates were defined as isolates exhibiting imipenem MIC ≥8 mg/L, as determined using the VITEK 2 system. The MICs of 11 other antimicrobial agents for the isolates were determined by the broth microdilution method. Iron-depleted CAMHB was used to determine the MICs of cefiderocol.

Results

The rates of colistin resistance of imipenem-resistant P. aeruginosa and imipenem-resistant A. baumannii were 5% and 10%, respectively. The MIC90 values of cefiderocol, ceftolozane/tazobactam, ceftazidime/avibactam, tigecycline and colistin were as follows: imipenem-resistant P. aeruginosa: 1, 4, 16, >4 and 2 mg/L; imipenem-resistant A. baumannii: 8, >64, >64, 4 and 2 mg/L; and S. maltophilia: 0.25, >64, >64, 2 and >8 mg/L, respectively. For imipenem-resistant A. baumannii isolates, the MICs of cefiderocol, ceftolozane/tazobactam and ceftazidime/avibactam were ≤4 mg/L for 88%, 8% and 1% of the isolates, respectively. Cefiderocol MICs were ≤4 mg/L for the five colistin-resistant imipenem-resistant P. aeruginosa isolates and 70% of the 10 colistin-resistant imipenem-resistant A. baumannii isolates.

Conclusions

Cefiderocol exhibited more potent in vitro activity than ceftolozane/tazobactam and ceftazidime/avibactam against imipenem-resistant P. aeruginosa, imipenem-resistant A. baumannii and S. maltophilia isolates.

Pneumococcal carriage in vaccine-eligible children and unvaccinated infants in Lao PDR two years following the introduction of the 13-valent pneumococcal conjugate vaccine

Pneumococcal carriage is a prerequisite for disease, and underpins herd protection provided by pneumococcal conjugate vaccines (PCVs). There are few data on the impact of PCVs in lower income settings, particularly in Asia. In 2013, the Lao People's Democratic Republic (Lao PDR) introduced 13-valent PCV (PCV13) as a 3 + 0 schedule (doses at 6, 10 and 14 weeks of age) with limited catch-up vaccination. We conducted two cross-sectional carriage surveys (pre- and two years post-PCV) to assess the impact of PCV13 on nasopharyngeal pneumococcal carriage in 5-8 week old infants (n = 1000) and 12-23 month old children (n = 1010). Pneumococci were detected by quantitative real-time PCR, and molecular serotyping was performed using DNA microarray. Post PCV13, there was a 23% relative reduction in PCV13-type carriage in children aged 12-23 months (adjusted prevalence ratio [aPR] 0.77 [0.61-0.96]), and no significant change in non-PCV13 serotype carriage (aPR 1.11 [0.89-1.38]). In infants too young to be vaccinated, there was no significant change in carriage of PCV13 serotypes (aPR 0.74 [0.43-1.27]) or non-PCV13 serotypes (aPR 1.29 [0.85-1.96]), although trends were suggestive of indirect effects. Over 70% of pneumococcal-positive samples contained at least one antimicrobial resistance gene, which were more common in PCV13 serotypes (p < 0.001). In 12-23 month old children, pneumococcal density of both PCV13 serotypes and non-PCV13 serotypes was higher in PCV13-vaccinated compared with undervaccinated children (p = 0.004 and p < 0.001, respectively). This study provides evidence of PCV13 impact on carriage in a population without prior PCV7 utilisation, and provides important data from a lower-middle income setting in Asia. The reductions in PCV13 serotype carriage in vaccine-eligible children are likely to result in reductions in pneumococcal transmission and disease in Lao PDR.

Prevalence, trend and antimicrobial susceptibility of Methicillin Resistant Staphylococcus aureus in Nigeria: a systematic review

BACKGROUND

Evidence to demonstrate the prevalence and trend of Methicillin Resistant Staphylococcus aureus (MRSA) infection in Nigeria is scarce. This review evaluates the prevalence, trend and antimicrobial susceptibility of clinical MRSA isolates reported in published studies.

METHOD

Electronic search (PubMed, Scopus and Google scholar) was conducted using the following search terms: "MRSA OR Methicillin Resistant Staphylococcus aureus AND Nigeria." Reference list of selected studies was scanned to identify more studies. Studies published between 2007 and 2017 that tested at least 30 non-duplicate S. aureus isolates were selected. An independent reviewer extracted data from the studies using a standardized form.

RESULTS

Twelve studies were included in this review. Overall, prevalence of MRSA infection increased from 18.3% (2009) to 42.3% (2013). The prevalence of MRSA infection was less than 50% in all the regions during the period under review. There was a decline in the prevalence of MRSA infection in the North-East (from 12.5% to 8.0%) between 2007 and 2012, and an increase in the South-West (from 20.2% to 47.4%) between 2006 and 2010. Wound, blood and urine specimens had the highest proportion of MRSA isolates. Non-susceptibility of MRSA strains to cotrimoxazole and tetracycline was greater than 85%.

CONCLUSION

Prevalence of MRSA infection in Nigeria is rising, albeit regional variations. Non-susceptibility to commonly prescribed, orally available and inexpensive antibiotics was high. Antimicrobial resistance surveillance system, infection control, and antimicrobial stewardship interventions are recommended.

A new group of compounds derived from 4-, 5-, 6- and 7-aminoindoles with antimicrobial activity

Introduction. The problem of antibiotic resistance of microorganisms is becoming more urgent in the twenty-first century. Microorganisms possess an evolutionary adaptive capacity. Non-adherence to the basic principles of rational antibiotic therapy leads to menacing consequences. More and more pathogenic microbes are becoming resistant to two or more antibiotics. The search for new compounds with antimicrobial activity is one of the principles for overcoming the antibiotic resistance of microorganisms.

Materials and methods. Eighteen test-strains of microorganisms and more than 2000 clinical strains of microorganisms, representating the families Micrococcaceae, Streptococcaceae, Enterobacteriaceae, Moraxellaceae, Pseudomonadaceae, Sphingomonadaceae, Xanthomonadaceae were studied for sensitivity to the compounds derived from 4-, 5-, 6- and 7-aminoindoles. A method of serial dilutions to determine the minimal inhibitory concentration (MIC) of the compounds under study was used in the study, as well as a disc diffusion method.

Results and discussion. Sensitivity of the test-strains and of clinical strains of microorganisms to the resulting compounds was studied. The compounds based on substituted 4-, 5-, 6-, 7-aminoindoles showed different activity against the test strains and experimental strains of microorganisms in vitro. It was found that the marked antibacterial activity was exhibited by the compounds containing a trifluoromethyl group. The most significant activity was noted in amides and pyrroloquinolones based on 4-aminoindole, 6-aminoindole and 7-aminoindole.The most effective compounds with laboratory codes 5D, 7D, 39D, S3, HD, 4D showed a pronounced antibacterial activity.

Conclusion. Antimicrobial activity of the substituted amides and pyrroloquinolines on the basis of 4-, 5-, 6-, 7-aminoindoles was etermined in our study, as well as the spectra of their action against Gram-positive and Gram-negative microorganisms, which are causative agents of non-specific and certain specific human infectious diseases. Moreover, we evaluated the synthetic potentials of the substituted 4-, 5-, 6-, 7-aminoindoles as the starting compounds for synthesizing a series of indolylamides and pyrroloquinolines. Also, the prospects for targeted synthesis of biologically active compounds based on indole-type aromatic amines were determined.

Antimicrobial stewardship for acute-care hospitals: An Asian perspective

Inappropriate use of antibiotics is contributing to a serious antimicrobial resistance problem in Asian hospitals. Despite resource constraints in the region, all Asian hospitals should implement antimicrobial stewardship (AMS) programs to optimize antibiotic treatment, improve patient outcomes, and minimize antimicrobial resistance. This document describes a consensus statement from a panel of regional experts to help multidisciplinary AMS teams design programs that suit the needs and resources of their hospitals. In general, AMS teams must decide on appropriate interventions (eg, prospective audit and/or formulary restriction) for their hospital, focusing on the most misused antibiotics and problematic multidrug-resistant organisms. This focus is likely to include carbapenem use with the goal to reduce carbapenem-resistant gram-negative bacteria. Rather than initially trying to introduce a comprehensive, hospital-wide AMS program, it would be practical to begin by pilot testing a simple program based on 1 achievable core intervention for the hospital. AMS team members must work together to determine the most suitable AMS interventions to implement in their hospitals and how best to put them into practice. Continuous monitoring and feedback of outcomes to the AMS teams, hospital administration, and prescribers will enhance sustainability of the AMS programs.

The return of Pfeiffer's bacillus: Rising incidence of ampicillin resistance in Haemophilus influenzae

Haemophilus influenzae, originally named Pfeiffer's bacillus after its discoverer Richard Pfeiffer in 1892, was a major risk for global health at the beginning of the 20th century, causing childhood pneumonia and invasive disease as well as otitis media and other upper respiratory tract infections. The implementation of the Hib vaccine, targeting the major capsule type of H. influenzae, almost eradicated the disease in countries that adapted the vaccination scheme. However, a rising number of infections are caused by non-typeable H. influenzae (NTHi), which has no capsule and against which the vaccine therefore provides no protection, as well as other serotypes equally not recognised by the vaccine. The first line of treatment is ampicillin, but there is a steady rise in ampicillin resistance. This is both through acquired as well as intrinsic mechanisms, and is cause for serious concern and the need for more surveillance. There are also increasing reports of new modifications of the intrinsic ampicillin-resistance mechanism leading to resistance against cephalosporins and carbapenems, the last line of well-tolerated drugs, and ampicillin-resistant H. influenzae was included in the recently released priority list of antibiotic-resistant bacteria by the WHO. This review provides an overview of ampicillin resistance prevalence and mechanisms in the context of our current knowledge about population dynamics of H. influenzae.

Excess body weight and age associated with the carriage of fluoroquinolone and third-generation cephalosporin resistance genes in commensal Escherichia coli from a cohort of urban Vietnamese children

PURPOSE

Antimicrobial-resistant bacterial infections in low- and middle-income countries (LMICs) are a well-established global health issue. We aimed to assess the prevalence of and epidemiological factors associated with the carriage of ciprofloxacin- and ceftriaxone-resistant Escherichia coli and associated resistance genes in a cohort of 498 healthy children residing in urban Vietnam.

METHODOLOGY

We cultured rectal swabs onto MacConkey agar supplemented with resistant concentrations of ciprofloxacin and ceftriaxone. Additionally, we screened meta-E. coli populations by conventional PCR to detect plasmid-mediated quinolone resistance (PMQR)- and extended-spectrum β-lactamase (ESBL)-encoding genes. We measured the associations between phenotypic/genotypic resistance and demographic characteristics using logistic regression.Results/Key findings. Ciprofloxacin- and ceftriaxone-resistant E. coli were cultured from the faecal samples of 67.7 % (337/498) and 80.3 % (400/498) of children, respectively. The prevalence of any associated resistance marker in the individual samples was 86.7 % (432/498) for PMQR genes and 90.6 % (451/498) for β-lactamase genes. Overweight children were significantly more likely to carry qnr genes than children with lower weight-for-height z-scores [odds ratios (OR): 1.24; 95 % confidence interval (CI): 10.5-1.48 for each unit increase in weight for height; P=0.01]. Additionally, younger children were significantly more likely to carry ESBL CTX-M genes than older children (OR: 0.97, 95 % CI: 0.94-0.99 for each additional year, P=0.01).

CONCLUSION

The carriage of genotypic and phenotypic antimicrobial resistance is highly prevalent among E. coli in healthy children in the community in Vietnam. Future investigations on the carriage of antimicrobial resistant organisms in LMICs should focus on the progression of carriage from birth and structure of the microbiome in obesity.

Extended-spectrum β-lactamase prevalence and virulence factor characterization of enterotoxigenic Escherichia coli responsible for acute diarrhea in Nepal from 2001 to 2016

Background

Multidrug-resistant (MDR) Gram-negative bacterial species are an increasingly dangerous public health threat, and are now endemic in many areas of South Asia. However, there are a lack of comprehensive data from many countries in this region determining historic and current MDR prevalence. Enterotoxigenic Escherichia coli (ETEC) is a leading cause of both acute infant diarrhea and traveler’s diarrhea in Nepal. The MDR prevalence and associated resistance mechanisms of ETEC isolates responsible for enteric infections in Nepal are largely unknown.

Methods

A total of 265 ETEC isolates were obtained from acute diarrheal samples (263/265) or patient control samples (2/265) at traveler’s clinics or regional hospitals in Nepal from 2001 to 2016. Isolates were screened for antibiotic resistance, to include extended spectrum beta-lactamase (ESBL) production, via the Microscan Automated Microbiology System. ETEC virulence factors, specifically enterotoxins and colonization factors (CFs), were detected using multiplex PCR, and prevalence in the total isolate population was compared to ESBL-positive isolates. ESBL-positive isolates were assessed using multiplex PCR for genetic markers potentially responsible for observed resistance.

Results

A total of 118/265 (44.5%) ETEC isolates demonstrated resistance to ≥2 antibiotics. ESBL-positive phenotypes were detected in 40/265 isolates, with isolates from 2008, 2013, 2014, and 2016 demonstrating ESBL prevalence rates of 1.5, 34.5, 31.2, and 35.0% respectively. No difference was observed in overall enterotoxin characterization between the total ETEC and ESBL-positive populations. The CFs CS2 (13.6%), CS3 (25.3%), CS6 (30.2%), and CS21 (62.6%) were the most prevalent in the total ETEC population. The ESBL-positive ETEC isolates exhibited a higher association trend with the CFs CS2 (37.5%), CS3 (35%), CS6 (42.5%), and CS21 (67.5%). The primary ESBL gene identified was bla_CTX-M-15 (80%), followed by bla_SHV-12 (20%) and bla_CTX-M-14 (2.5%). The beta-lactamase genes bla_TEM-1 (40%) and bla_CMY-2 (2.5%) were also identified. It was determined that 42.5% of the ESBL-positive isolates carried multiple resistance genes.

Conclusion

Over 30% of ETEC isolates collected post-2013 and evaluated in this study demonstrated ESBL resistance. Persistent surveillance and characterization of enteric ETEC isolates are vital for tracking the community presence of MDR bacterial species in order to recommend effective treatment strategies and help mitigate the spread of resistant pathogens.

Genomic Characterization of Nonclonal mcr-1-Positive Multidrug-Resistant Klebsiella pneumoniae from Clinical Samples in Thailand

Multidrug-resistant Klebsiella pneumoniae strains are one of the most prevalent causes of nosocomial infections and pose an increasingly dangerous public health threat. The lack of remaining treatment options has resulted in the utilization of older drug classes, including colistin. As a drug of last resort, the discovery of plasmid-mediated colistin resistance by mcr-1 denotes the potential development of pandrug-resistant bacterial pathogens. To address the emergence of the mcr-1 gene, 118 gram-negative Enterobacteriaceae isolated from clinical samples collected at Queen Sirikit Naval Hospital in Chonburi, Thailand were screened for colistin resistance using automated antimicrobial susceptibility testing and conventional PCR screening. Two K. pneumoniae strains, QS17-0029 and QS17-0161, were positive for mcr-1, and both isolates were sequenced to closure using short- and long-read whole-genome sequencing. QS17-0029 carried 16 antibiotic resistance genes in addition to mcr-1, including 2 carbapenemases, bla_NDM-1 and bla_OXA-232. QS17-0161 carried 13 antibiotic resistance genes in addition to mcr-1, including the extended-spectrum β-lactamase bla_CTX-M-55. Both isolates carried multiple plasmids, but mcr-1 was located alone on highly similar 33.9 Kb IncX4 plasmids in both isolates. The IncX4 plasmid shared considerable homology to other mcr-1-containing IncX4 plasmids. This is the first report of a clinical K. pneumoniae strain from Thailand carrying mcr-1 as well as the first strain to simultaneously carry mcr-1 and multiple carbapenemase genes (QS17-0029). The identification and characterization of these isolates serves to highlight the urgent need for continued surveillance and intervention in Southeast Asia, where extensively drug-resistant pathogens are being increasingly identified in hospital-associated infections.

Antimicrobial resistance in urine and skin isolates in Timor-Leste

OBJECTIVES

High rates of antimicrobial resistance (AMR) are seen throughout Southeast Asia. However, limited AMR data exist for Timor-Leste, which is situated on the south-eastern portion of the Malay Archipelago. The purpose of this study was to identify AMR in bacteria isolated from urine and skin swabs from patients in Dili, the capital of Timor-Leste.

METHODS

Urine and skin swabs were collected from symptomatic patients in Timor-Leste and were processed for bacterial culture. Isolates were processed in Australia using a VITEK^®2 system for bacterial identification and to determine antimicrobial susceptibility according to Clinical and Laboratory Standards Institute (CLSI) guidelines.

RESULTS

A total of 154 urine isolates and 57 skin isolates were analysed. Of the Enterobacteriaceae, 35% were resistant to ceftriaxone with an extended-spectrum β-lactamase (ESBL)-producing phenotype. Carbapenem resistance was not observed in any of the Gram-negative isolates. Of the Staphylococcus aureus isolates, 11% were of the community-associated methicillin-resistant S. aureus (CA-MRSA) phenotype.

CONCLUSIONS

A moderately high proportion of Gram-negative urine isolates in Timor-Leste demonstrate phenotypic ESBL production, and a relatively low proportion of S. aureus isolates were methicillin-resistant. Improved understanding of AMR rates in Timor-Leste can help guide antimicrobial prescribing and inform antimicrobial stewardship strategies.

Boesenbergia rotunda (L.) Mansf. extract potentiates the antibacterial activity of some β-lactams against β-lactam-resistant staphylococci

OBJECTIVES

The purpose of this study was to investigate the effect of Boesenbergia rotunda (L.) Mansf. extract (BRE) and peptidoglycan inhibitor antibiotics, alone and in combination, against β-lactam-resistant staphylococci.

METHODS

Antibacterial and synergistic activities of BRE alone and in combination with ampicillin (AMP), cloxacillin (CLX), cefazolin (CZO) or vancomycin (VAN) were evaluated against two β-lactam-resistant Staphylococcus aureus (BRSA) isolates and one β-lactam-resistant Staphylococcus epidermidis (BRSE) isolate. The activities were confirmed by killing curve assays. The preliminary antimicrobial action was elucidated by transmission electron microscopy (TEM) and cytoplasmic membrane (CM) permeability assay.

RESULTS

All tested staphylococci were inhibited by BRE at a minimum inhibitory concentration (MIC) of 16μg/mL. Two BRSA strains showed high resistance to CLX, AMP and CZO, whilst BRSE was resistant to CLX and AMP. All tested isolates remained susceptible to VAN. Chequerboard assay demonstrated a fractional inhibitory concentration index (FICI) of 0.50 for the BRE+CLX combination against the BRSA strains. Killing curve determinations confirmed the antibacterial and synergistic activities. TEM revealed collapse of the CM in BRE-treated cells and damage both of the CM and peptidoglycan (PG) in BRE+CLX-treated cells. The CM permeability assay showed that either BRE or nisin alone as well as BRE+CLX significantly induced leakage of OD_260nm-absorbing materials.

CONCLUSIONS

BRE potentiated the activity of β-lactams, particularly CLX, against β-lactam-resistant staphylococci by damaging the CM and PG layer, leading to leakage of intracellular material. Combination of BRE and β-lactams provides a potential way forward in developing novel antistaphylococcal agents.

Bactericidal activity of self-assembled palmitic and stearic fatty acid crystals on highly ordered pyrolytic graphite

The wings of insects such as cicadas and dragonflies have been found to possess nanostructure arrays that are assembled from fatty acids. These arrays can physically interact with the bacterial cell membranes, leading to the death of the cell. Such mechanobactericidal surfaces are of significant interest, as they can kill bacteria without the need for antibacterial chemicals. Here, we report on the bactericidal effect of two of the main lipid components of the insect wing epicuticle, palmitic (C16) and stearic (C18) fatty acids. Films of these fatty acids were re-crystallised on the surface of highly ordered pyrolytic graphite. It appeared that the presence of two additional CH₂ groups in the alkyl chain resulted in the formation of different surface structures. Scanning electron microscopy and atomic force microscopy showed that the palmitic acid microcrystallites were more asymmetric than those of the stearic acid, where the palmitic acid microcrystallites were observed to be an angular abutment in the scanning electron micrographs. The principal differences between the two types of long-chain saturated fatty acid crystallites were the larger density of peaks in the upper contact plane of the palmitic acid crystallites, as well as their greater proportion of asymmetrical shapes, in comparison to that of the stearic acid film. These two parameters might contribute to higher bactericidal activity on surfaces derived from palmitic acid. Both the palmitic and stearic acid crystallite surfaces displayed activity against Gram-negative, rod-shaped Pseudomonas aeruginosa and Gram-positive, spherical Staphylococcus aureus cells. These microcrystallite interfaces might be a useful tool in the fabrication of effective bactericidal nanocoatings.

STATEMENT OF SIGNIFICANCE

Nanostructured cicada and dragonfly wing surfaces have been discovered to be able physically kill bacterial cells. Here, we report on the successful fabrication of bactericidal three-dimensional structures of two main lipid components of the epicuticle of insect wings, palmitic (C16) and stearic (C18) acids. After crystallisation onto highly ordered pyrolytic graphite, both the palmitic and stearic acid films displayed bactericidal activity against both Gram-negative Pseudomonas aeruginosa and Gram-positive Staphylococcus aureus cells. The simplicity of the production of these microcrystallite interfaces suggests that a fabrication technique, based on solution deposition, could be an effective technique for the application of bactericidal nanocoatings.

Novel antimicrobial peptide-modified azithromycin-loaded liposomes against methicillin-resistant Staphylococcus aureus

Infections caused by multidrug-resistant bacteria, such as methicillin-resistant Staphylococcus aureus (MRSA), have become a public threat; therefore, development of new antimicrobial drugs or strategies is urgently required. In this study, a new antibacterial peptide DP7-C (Chol-suc-VQWRIRVAVIRK-NH2) and DP7-C-modified azithromycin (AZT)-loaded liposomes (LPs) are developed for the treatment of MRSA infection, and it was found that DP7-C inserted into the LP lipid bilayer not only functioned as a carrier to encapsulate the antibiotic AZT but also synergized the antibacterial effect of the encapsulated AZT. In vitro assays showed that DP7-C-modified LPs possessed sustained drug release profile and immune regulatory effect and did not show obvious cytotoxicity in mammal cells, but they did not possess direct antibacterial activity in vitro. In vivo studies revealed that DP7-C-modified LPs did not exhibit obvious side effects or toxicity in mice but were able to significantly reduce the bacterial counts in an MRSA-infectious mouse model and possessed high antibacterial activity. In particular, DP7-C-modified AZT-loaded LPs showed more positive therapeutic effects than either DP7-C-modified blank LPs or nonmodified AZT-loaded LPs treatment alone. Molecular mechanism studies demonstrated that DP7-C formulations effectively upregulated the production of anti-inflammatory cytokines and chemokines without inducing harmful immune response, suggesting that DP7-C was synergistic with AZT against the bacterial infection by activating the innate immune response. Most importantly, although DP7-C activated the innate immune response, it did not possess direct antibacterial activity in vitro, indicating that DP7-C did not possess the potential to induce bacteria resistance. The findings indicate that DP7-C-modified AZT-loaded LPs developed in this study have a great potential required for the clinical treatment of MRSA infections.

Are we investing wisely? A systematic analysis of nationally funded antimicrobial resistance projects in Republic of Korea, 2003-2013

From 2003 to 2013, South Korea has conducted the National Antimicrobial Resistance Safety Control Program (NARSCP). The purpose of the current study was to systematically review national antimicrobial resistance (AMR) research trends and to provide guidance on future allocation of research funding to enable a comprehensive approach in AMR control. This study collected project reports related to AMR published by the Ministry of Food and Drug Safety, the Ministry of Health and Welfare and the Korea Centers for Disease Control and Prevention between 2003 and 2013. These reports were analysed by topics based on the AMR action plan of the World Health Organization (WHO), period of study, categories along the research pipeline and types of receiving institution. A total of 198 project reports were included, with total funding of US$18.3 million. Mean funding per award was US$92,750, with a median of US$71,714. Among the WHO-suggested criteria, the basic microbial research and surveillance sector accounts for 143 (72.2%) of all awards. Yearly project funding increased from US$961,476 in 2003 to US$1,553,294 in 2013. Operational research was 61.5% and product development was 0.7% of the basic microbial research and surveillance sector. By institution, academia received 145 awards (73.2%). During progress of the NARSCP, total research funding increased significantly, but most awards were focused on understanding the overall picture of the nationwide AMR status. More balanced funding is needed, and encouraging active participation of private and international sectors is also required in reducing AMR.

Molecular Analysis of Antibiotic Resistance Determinants and Plasmids in Malaysian Isolates of Multidrug Resistant Klebsiella pneumoniae

Infections caused by multidrug resistant Klebsiella pneumoniae have been increasingly reported in many parts of the world. A total of 93 Malaysian multidrug resistant K. pneumoniae isolated from patients attending to University of Malaya Medical Center, Kuala Lumpur, Malaysia from 2010-2012 were investigated for antibiotic resistance determinants including extended-spectrum beta-lactamases (ESBLs), aminoglycoside and trimethoprim/sulfamethoxazole resistance genes and plasmid replicons. CTX-M-15 (91.3%) was the predominant ESBL gene detected in this study. aacC2 gene (67.7%) was the most common gene detected in aminoglycoside-resistant isolates. Trimethoprim/sulfamethoxazole resistance (90.3%) was attributed to the presence of sul1 (53.8%) and dfrA (59.1%) genes in the isolates. Multiple plasmid replicons (1-4) were detected in 95.7% of the isolates. FIIK was the dominant replicon detected together with 13 other types of plasmid replicons. Conjugative plasmids (1-3 plasmids of ~3-100 kb) were obtained from 27 of 43 K. pneumoniae isolates. An ESBL gene (either CTX-M-15, CTX-M-3 or SHV-12) was detected from each transconjugant. Co-detection with at least one of other antibiotic resistance determinants [sul1, dfrA, aacC2, aac(6ˊ)-Ib, aac(6ˊ)-Ib-cr and qnrB] was noted in most conjugative plasmids. The transconjugants were resistant to multiple antibiotics including β-lactams, gentamicin and cotrimoxazole, but not ciprofloxacin. This is the first study describing the characterization of plasmids circulating in Malaysian multidrug resistant K. pneumoniae isolates. The results of this study suggest the diffusion of highly diverse plasmids with multiple antibiotic resistance determinants among the Malaysian isolates. Effective infection control measures and antibiotic stewardship programs should be adopted to limit the spread of the multidrug resistant bacteria in healthcare settings.

Bloodstream infections at a tertiary referral hospital in Yangon, Myanmar

BACKGROUND

Data regarding characteristics of bloodstream infections in Myanmar are limited.

METHODS

Blood culture results from all outpatients and inpatients were extracted from records of the Clinical Microbiology Laboratory, Yangon General Hospital, for the period 2005 through 2013.

RESULTS

Of 3865 blood cultures performed, 449 (11.6%) were positive for a pathogenic organism. Gram-negative bacteria was the most common organism group, accounting for 246 (55.5%) of 449 isolations. Staphylococcus aureus was the most common isolate, detected in 171 (38.1%) of 449 blood cultures. From 2005-2008 to 2009-2013 the proportion of all pathogenic isolates that were Gram-positive declined from 52.8% (167/316) to 20.3% (27/133) (p<0.001), whereas the proportion of Gram-negative bacteria rose from 45.6% (144/316) to 78.9% (105/133) (p<0.001), with non-fermentative bacilli accounting for much of this increase. Antimicrobial susceptibility testing demonstrated a high prevalence resistance of S. aureus to first-line antimicrobials such as erythromycin, penicillin and oxacillin. More than half of tested Escherichia coli and Citrobacter species showed resistance to amoxicillin-clavulanic acid, ceftriaxone or gentamicin.

CONCLUSIONS

Bloodstream infections are common among patients receiving blood culture at a tertiary hospital in Yangon, Myanmar. Our findings suggest that antimicrobial resistance among invasive bacteria is common, similar to patterns described elsewhere in the region, and highlight the need for locally adapted antimicrobial guidelines for sepsis management.