Antimicrobial Resistance in Invasive Bacterial Infections in Hospitalized Children, Cambodia, 2007-2016

Antimicrobial resistance among common bacterial pathogens in Indonesia: a systematic review

Background

The WHO Global Antimicrobial Resistance Surveillance System (GLASS) aims to describe antimicrobial resistance (AMR) patterns and trends in common bacterial pathogens, but data remain limited in many low and middle-income countries including Indonesia.

Methods

We systematically searched Embase, PubMed and Global Health Database and three Indonesian databases for original peer-reviewed articles in English and Indonesian, published between January 1, 2000 and May 25, 2023, that reported antimicrobial susceptibility for the 12 GLASS target pathogens from human samples. Pooled AMR prevalence estimates were calculated for relevant pathogen-antimicrobial combinations accounting for the sampling weights of the studies (PROSPERO: CRD42019155379).

Findings

Of 2182 search hits, we included 102 papers, comprising 19,517 bacterial isolates from hospitals (13,647) and communities (5870). In hospital settings, 21.6% of Klebsiella pneumoniae isolates, 18.3% of Escherichia coli isolates, 35.8% of Pseudomonas aeruginosa isolates and 70.7% of Acinetobacter baumannii isolates were carbapenem-resistant; 29.9% of Streptococcus pneumoniae isolates were penicillin-resistant; and 22.2% of Staphylococcus aureus isolates were methicillin-resistant. Hospital prevalence of carbapenem-resistant K. pneumoniae and E. coli, and penicillin-resistant S. pneumoniae increased over time. In communities, 28.3% of K. pneumoniae isolates and 15.7% of E. coli isolates were carbapenem-resistant, 23.9% of S. pneumoniae isolates were penicillin-resistant, and 11.1% of S. aureus isolates were methicillin-resistant. Data were limited for the other pathogens.

Interpretation

AMR prevalence estimates were high for critical gram-negative bacteria. However, data were insufficient to draw robust conclusions about the full contemporary AMR situation in Indonesia. Implementation of national AMR surveillance is a priority to address these gaps and inform context-specific interventions.

Funding

Wellcome Africa Asia Programme Vietnam.

The causes of bacterial bloodstream infections and antimicrobial resistance patterns in children attending a secondary care hospital in Bhaktapur, Nepal, 2017-2022: a retrospective study

Objectives

Data on antimicrobial resistance (AMR) among children in Nepal are limited. Here we have characterized the causes of bacterial bloodstream infections (BSIs), antimicrobial resistance patterns and the mechanisms of β-lactamase production in Enterobacterales among children attending outpatient and inpatient departments of a secondary care paediatric hospital in Nepal.

Methods

We retrospectively collected demographic and clinical data of culture-proven bacterial BSIs between January 2017 and December 2022 among children <18 years attending a 50-bedded paediatric hospital. Stored isolates were subcultured for antimicrobial susceptibility testing against commonly used antimicrobials. Enterobacterales displaying non-susceptibility to β-lactams were phenotypically and genotypically investigated for ESBLs, plasmid-mediated AmpC (pAmpC) β-lactamases and carbapenemases.

Results

A total of 377 significant bacteria were isolated from 27 366 blood cultures. Among 91 neonates with a BSI, Klebsiella pneumoniae (n = 39, 42.4%), Pseudomonas aeruginosa (n = 15, 16.3%) and Acinetobacter baumannii complex (n = 13, 14.1%) were most common. In the non-neonates, 275/285 (96.5%) infections were community-acquired including Staphylococcus aureus (n = 89, 32.4%), Salmonella Typhi (n = 54, 19.6%) and Streptococcus pneumoniae (n = 32, 11.6%). Among the 98 S. aureus, 29 (29.6%) were methicillin-resistant Staphylococcus aureus. K. pneumoniae and Escherichia coli demonstrated non-susceptibility to extended-spectrum cephalosporins and carbapenems in both community and hospital-acquired cases. For E. coli and K. pneumoniae, blaCTX-M (45/46), blaEBC (7/10) and blaOXA-48 (5/6) were common among their respective groups.

Conclusions

We determined significant levels of AMR among children attending a secondary care paediatric hospital with BSI in Nepal. Nationwide surveillance and implementation of antimicrobial stewardship policies are needed to combat the challenge imposed by AMR.

The barriers and facilitators of implementing a national laboratory-based AMR surveillance system in Cambodia: key informants' perspectives and assessments of microbiology laboratories

Background

Collecting data on antimicrobial resistance (AMR) is an essential approach for defining the scope of the AMR problem, developing evidence-based interventions and detecting new and emerging resistances. Our study aimed to identify key factors influencing the implementation of a laboratory-based AMR surveillance system in Cambodia. This will add additional insights to the development of a sustainable and effective national AMR surveillance system in Cambodia and other low- and middle-income countries.

Methods

Key informants with a role in governing or contributing data to the laboratory-based surveillance system were interviewed. Emerging themes were identified using the framework analysis method. Laboratories contributing to the AMR surveillance system were assessed on their capacity to conduct quality testing and report data. The laboratory assessment tool (LAT), developed by the World Health Organisation (WHO), was adapted for assessment of a diagnostic microbiology laboratory covering quality management, financial and human resources, data management, microbiology testing performance and surveillance capacity.

Results

Key informants identified inadequate access to laboratory supplies, an unsustainable financing system, limited capacity to collect representative data and a weak workforce to be the main barriers to implementing an effective surveillance system. Consistent engagement between microbiology staff and clinicians were reported to be a key factor in generating more representative data for the surveillance system. The laboratory assessments identified issues with quality assurance and data analysis which may reduce the quality of data being sent to the surveillance system and limit the facility-level utilisation of aggregated data. A weak surveillance network and poor guidance for outbreak response were also identified, which can reduce the laboratories' opportunities in detecting critical or emerging resistance occurring in the community or outside of the hospital's geographical coverage.

Conclusion

This study identified two primary concerns: ensuring a sustainable and quality functioning of microbiology services at public healthcare facilities and overcoming sampling bias at sentinel sites. These issues hinder Cambodia's national AMR surveillance system from generating reliable evidence to incorporate into public health measures or clinical interventions. These findings suggest that more investments need to be made into microbiology diagnostics and to reform current surveillance strategies for enhanced sampling of AMR cases at hospitals.

Infections transmitted via the faecal-oral route: a simple score for a global risk map

INTRODUCTION

Faecal-oral transmission refers to the process whereby disease is transmitted via the faeces of an infected individual to the mouth of a susceptible individual. This transmission can occur through failures in sanitation systems leading to exposure via various routes in particular contaminated water, food, and hands. Travellers' diarrhoea is the most common travel-related illness. A score could enhance risk assessment and pre-travel advice.

METHODS

A simple score was developed based on the frequency of defecating in the open (country prevalence > 1%), occurrence of cholera in the period between 2021 and 2017 (one or more case in a country) and reported typhoid fever cases between 2015 and 2019.

RESULTS

Data were available for 199 out of 214 countries for the score to be applied. 19% of the 199 countries scored as high risk countries for faecal-oral transmission (score 3), 47% as medium risk (score 2), and 34% as minimal risk (score 0). The percentage of countries scoring 3 was highest in Africa (63%) and lowest in Europe and Oceania (score 0).

CONCLUSIONS

A global risk map was developed based on a simple score that could aid travel medicine providers in providing pre-travel risk assessment. For travellers to high and medium risk countries, pre-travel consultation must include detailed advice on food and water hygiene.

Microbiological profile of bloodstream infections and antimicrobial resistance patterns at a tertiary referral hospital in Amazon, Brazil

BACKGROUND

Bloodstream infections (BSI) are a global health issue, leading to high mortality and morbidity among hospitalized patients.

METHODS

A retrospective, observational and descriptive study was conducted by reviewing blood culture records collected from patients with suspected BSI, between January 2017 and December 2019.

RESULTS

The most frequent antimicrobial resistant (AMR) pathogens were methicillin-resistantStaphylococcus aureus(MRSA) (40%), methicillin-resistantS. epidermidis (MRSE) (9.5%), and extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae (35.3%).

CONCLUSIONS

Our findings underscore the importance of continued vigilance and advocate for the rational use of antimicrobial agents.

Methicillin resistant Staphylococcus aureus isolated from surgical patients in Cambodia over a 10-year period

Methicillin-resistant Staphylococcus aureus (MRSA) related surgical infections are a global challenge. The burden of antimicrobial resistance is high throughout South-East Asia, and this is reflected in our local institution in Cambodia. Between 2011 and 2013, we analysed 251 wound swab samples at the Children's Surgical Centre, Phnom Penh; 52.5% of the Staphylococcus aureus isolates (n = 52/99) were MRSA positive. Ten years on, we have sought to investigate whether there is a difference in MRSA rates within our adult and paediatric patient population. Between 2020 and 2022, MRSA rates in our patient population have remained similar at 53.8% (n = 42/78). Resistance profiles of MRSA isolates have also remained similar with a significant proportion of MRSA still showing sensitivity to trimethoprim-sulfamethoxazole and tetracycline. We also find that patients presenting with wound infection secondary to trauma or orthopaedic implants had greater propensity to yield MRSA.

The role of the light source in antimicrobial photodynamic therapy

Antimicrobial photodynamic therapy (APDT) is a promising approach to fight the growing problem of antimicrobial resistance that threatens health care, food security and agriculture. APDT uses light to excite a light-activated chemical (photosensitiser), leading to the generation of reactive oxygen species (ROS). Many APDT studies confirm its efficacy in vitro and in vivo against bacteria, fungi, viruses and parasites. However, the development of the field is focused on exploring potential targets and developing new photosensitisers. The role of light, a crucial element for ROS production, has been neglected. What are the main parameters essential for effective photosensitiser activation? Does an optimal light radiant exposure exist? And finally, which light source is best? Many reports have described the promising antibacterial effects of APDT in vitro, however, its application in vivo, especially in clinical settings remains very limited. The restricted availability may partially be due to a lack of standard conditions or protocols, arising from the diversity of selected photosensitising agents (PS), variable testing conditions including light sources used for PS activation and methods of measuring anti-bacterial activity and their effectiveness in treating bacterial infections. We thus sought to systematically review and examine the evidence from existing studies on APDT associated with the light source used. We show how the reduction of pathogens depends on the light source applied, radiant exposure and irradiance of light used, and type of pathogen, and so critically appraise the current state of development of APDT and areas to be addressed in future studies. We anticipate that further standardisation of the experimental conditions will help the field advance, and suggest key optical and biological parameters that should be reported in all APDT studies. More in vivo and clinical studies are needed and are expected to be facilitated by advances in light sources, leading to APDT becoming a sustainable, alternative therapeutic option for bacterial and other microbial infections in the future.

Detection of maternal transmission of resistant Gram-negative bacteria in a Cambodian hospital setting

Infection with Extended-spectrum beta-lactamase -producing Enterobacterales (ESBL-E) is common in infants and leads to increased intensive care unit admission and mortality, but the role of maternal transmission in colonization of infants is unclear. Using paired isolates from 50 pairs of mothers and neonates admitted to a Cambodian hospital, we investigated antimicrobial resistance in Escherichia coli and Klebsiella pneumoniae using whole genome sequencing. We detected a wide variety of ESBL-E genes present in this population along with high levels of multidrug resistance. From 21 pairs where the same organism was present in both mother and neonate, we identified eight pairs with identical or near-identical isolates from both individuals suggestive of transmission at or around birth, including a pair with transmission of multiple strains. We found no evidence for transmission of plasmids only from mother to infant. This suggests vertical transmission outside hospitals as a common cause of ESBL-E colonization in neonates.

Diversity and Dissemination of Methicillin-Resistant Staphylococcus aureus (MRSA) Genotypes in Southeast Asia

Methicillin-resistant Staphylococcus aureus (MRSA) is a successful pathogen that has achieved global dissemination, with high prevalence rates in Southeast Asia. A huge diversity of clones has been reported in this region, with MRSA ST239 being the most successful lineage. Nonetheless, description of MRSA genotypes circulating in the Southeast Asia region has, until now, remained poorly compiled. In this review, we aim to provide a better understanding of the molecular epidemiology and distribution of MRSA clones in 11 Southeast Asian countries: Singapore, Malaysia, Thailand, Vietnam, Cambodia, Lao People's Democratic Republic (PDR), Myanmar, Philippines, Indonesia, Brunei Darussalam, and Timor-Leste. Notably, while archaic multidrug-resistant hospital-associated (HA) MRSAs, such as the ST239-III and ST241-III, were prominent in the region during earlier observations, these were then largely replaced by the more antibiotic-susceptible community-acquired (CA) MRSAs, such as ST22-IV and PVL-positive ST30-IV, in recent years after the turn of the century. Nonetheless, reports of livestock-associated (LA) MRSAs remain few in the region.

Gastrointestinal Carriage of Antimicrobial Resistance in School-Aged Children in Three Municipalities of Timor-Leste

Invasive bacterial infections are a leading cause of death in children, primarily in low- and middle-income countries (LMIC). Links between carriage of antimicrobial-resistant organisms and more resistant infections have been established; however, little has been reported regarding community carriage of antibiotic-resistant organisms such as extended-spectrum β-lactamase (ESBL)-producing Enterobacterales in LMIC. The aim of this study was to determine colonic carriage of ESBL-producing fluoroquinolone- and aminoglycoside-resistant Enterobacterales in healthy children in three municipalities of Timor-Leste. In November 2020, 621 stool samples were collected from school-aged children and underwent screening for the presence of Enterobacterales species and antimicrobial resistance (AMR). Ciprofloxacin-resistant Gram-negative organisms were cultured from 16.5% (95% CI 6.2−26.9), and gentamicin resistance was identified in 6.8% (95% CI 2.8−10.7). Compared to the prevalence of ciprofloxacin resistance in Dili (36.1%), there was significantly lower prevalence in the rural municipalities of Ermera (12.9%; AOR 0.38, 95% CI 0.24−0.60, p < 0.001) and Manufahi (4.5%; AOR 0.07, 95% CI 0.01−0.51, p = 0.009). The overall cluster-adjusted prevalence of ESBL-producing bacteria was 8.3%, with no significant differences between municipalities. This study demonstrates high rates of carriage of AMR among school-aged children in Timor-Leste, with higher rates observed in Dili compared to rural municipalities. Empiric antibiotic guidelines should include recommendations for treating community-acquired infections that account for the possibility of antimicrobial resistance.

Impact of delayed processing of positive blood cultures on organism detection: a prospective multi-centre study

Background

Blood cultures remain the gold standard investigation for the diagnosis of bloodstream infections. In many locations, quality-assured processing of positive blood cultures is not possible. One solution is to incubate blood cultures locally, and then transport bottles that flag positive to a central reference laboratory for organism identification and antimicrobial susceptibility testing. However, the impact of delay between the bottle flagging positive and subsequent sub-culture on the viability of the isolate has received little attention.

Methods

This study evaluated the impact of delays to sub-culture (22 h to seven days) in three different temperature conditions (2–8 °C, 22–27 °C and 35 ± 2 °C) for bottles that had flagged positive in automated detection systems using a mixture of spiked and routine clinical specimens. Ninety spiked samples for five common bacterial causes of sepsis (Escherichia coli, Haemophilus influenzae, Staphylococcus aureus, Streptococcus agalactiae and Streptococcus pneumoniae) and 125 consecutive positive clinical blood cultures were evaluated at four laboratories located in Cambodia, Lao PDR and Thailand. In addition, the utility of transport swabs for preserving organism viability was investigated.

Results

All organisms were recoverable from all sub-cultures in all temperature conditions with the exception of S. pneumoniae, which was less likely to be recoverable after longer delays (> 46–50 h), when stored in hotter temperatures (35 °C), and from BacT/ALERT when compared with BACTEC blood culture bottles. Storage of positive blood culture bottles in cooler temperatures (22–27 °C or below) and the use of Amies bacterial transport swabs helped preserve viability of S. pneumoniae.

Conclusions

These results have practical implications for the optimal workflow for blood culture bottles that have flagged positive in automated detection systems located remotely from a central processing laboratory, particularly in tropical resource-constrained contexts.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-022-07504-1.

Early-onset neonatal sepsis and antibiotic use in Indonesia: a descriptive, cross-sectional study

BACKGROUND

Early diagnosis and prompt antibiotic treatment are crucial to reducing morbidity and mortality of early-onset sepsis (EOS) in neonates. However, this strategy remains challenging due to non-specific clinical findings and limited facilities. Inappropriate antibiotics use is associated with ineffective therapy and adverse outcomes. This study aims to determine the characteristics of EOS and use of antibiotics in the neonatal-intensive care units (NICUs) in Indonesia, informing efforts to drive improvements in the prevention, diagnosis, and treatment of EOS.

METHODS

A descriptive study was conducted based on pre-intervention data of the South East Asia-Using Research for Change in Hospital-acquired Infection in Neonates project. Our study population consisted of neonates admitted within 72 h of life to the three participating NICUs. Neonates who presented with three or more clinical signs or laboratory results consistent with sepsis and who received antibiotics for 5 consecutive days were considered to have EOS. Culture-proven EOS was defined as positive blood or cerebrospinal fluid culture. Type and duration of antibiotics used were also documented.

RESULTS

Of 2,509 neonates, 242 cases were suspected of having EOS (9.6%) with culture-proven sepsis in 83 cases (5.0% of neonatal admissions in hospitals with culture facilities). The causative organisms were mostly gram-negative bacteria (85/94; 90.4%). Ampicillin / amoxicillin and amikacin were the most frequently prescribed antibiotics in hospitals with culture facilities, while a third-generation cephalosporin was mostly administered in hospital without culture facilities. The median durations of antibiotic therapy were 19 and 9 days in culture-proven and culture-negative EOS groups, respectively.

CONCLUSIONS

The overall incidence of EOS and culture-proven EOS was high in Indonesia, with diverse and prolonged use of antibiotics. Prospective antibiotic surveillance and stewardship interventions are required.

MgrB-Dependent Colistin Resistance in Klebsiella pneumoniae Is Associated with an Increase in Host-to-Host Transmission

Due to its high transmissibility, Klebsiella pneumoniae is one of the leading causes of nosocomial infections. Here, we studied the biological cost of colistin resistance, an antibiotic of last resort, in this opportunistic pathogen using a murine model of gut colonization and transmission. Colistin resistance in K. pneumoniae is commonly the result of the inactivation of the small regulatory protein MgrB. Without a functional MgrB, the two-component system PhoPQ is constitutively active, leading to an increase in lipid A modifications and subsequent colistin resistance. Using an isogenic mgrB deletion mutant (MgrB-), we demonstrate that the mutant's colistin resistance is not associated with a fitness defect under in vitro growth conditions. However, in our murine model of K. pneumoniae gastrointestinal (GI) colonization, the MgrB- colonizes the gut poorly, allowing us to identify a fitness cost. Moreover, the MgrB- mutant has higher survival outside the host compared with the parental strain. We attribute this enhanced survivability to dysregulation of the PhoPQ two-component system and accumulation of the master stress regulator RpoS. The enhanced survival of MgrB- may be critical for its rapid host-to-host transmission observed in our model. Together, our data using multiple clinical isolates demonstrate that MgrB-dependent colistin resistance in K. pneumoniae comes with a biological cost in gut colonization. However, this cost is mitigated by enhanced survival outside the host and consequently increases its host-to-host transmission. Additionally, it underscores the importance of considering the entire life cycle of a pathogen to determine the actual biological cost associated with antibiotic resistance. IMPORTANCE The biological cost associated with colistin resistance in Klebsiella pneumoniae was examined using a murine model of K. pneumoniae gut colonization and fecal-oral transmission. A common mutation resulting in colistin resistance in K. pneumoniae is a loss-of-function mutation of the small regulatory protein MgrB that regulates the two-component system PhoPQ. Even though colistin resistance in K. pneumoniae comes with a fitness defect in gut colonization, it increases bacterial survival outside the host enabling it to transmit more effectively to a new host. The enhanced survival is dependent upon the accumulation of RpoS and dysregulation of the PhoPQ. Hence, our study expands our understanding of the underlying molecular mechanism contributing to the transmission of colistin-resistant K. pneumoniae.

Epidemiology of Extended-Spectrum Beta-Lactamase and Carbapenemase-Producing Enterobacterales in the Greater Mekong Subregion: A Systematic-Review and Meta-Analysis of Risk Factors Associated With Extended-Spectrum Beta-Lactamase and Carbapenemase Isolation

Background: Despite the rapid spread of extended-spectrum beta-lactamase (ESBL) producing-Enterobacterales (ESBL-E) and carbapenemase-producing Enterobacterales (CPE), little is known about the extent of their prevalence in the Greater Mekong Subregion (GMS). In this systematic review, we aimed to determine the epidemiology of ESBL-E and CPE in clinically significant Enterobacterales: Escherichia coli and Klebsiella pneumoniae from the GMS (comprising of Cambodia, Laos, Myanmar, Thailand, Vietnam and Yunnan province and Guangxi Zhuang region of China). Methods: Following a list of search terms adapted to subject headings, we systematically searched databases: Medline, EMBASE, Scopus and Web of Science for articles published on and before October 20th, 2020. The search string consisted of the bacterial names, methods involved in detecting drug-resistance phenotype and genotype, GMS countries, and ESBL and carbapenemase detection as the outcomes. Meta-analyses of the association between the isolation of ESBL from human clinical and non-clinical specimens were performed using the "METAN" function in STATA 14. Results: One hundred and thirty-nine studies were included from a total of 1,513 identified studies. Despite the heterogeneity in study methods, analyzing the prevalence proportions on log-linear model scale for ESBL producing-E. coli showed a trend that increased by 13.2% (95%CI: 6.1-20.2) in clinical blood specimens, 8.1% (95%CI: 1.7-14.4) in all clinical specimens and 17.7% (95%CI: 4.9-30.4) increase in carriage specimens. Under the log-linear model assumption, no significant trend over time was found for ESBL producing K. pneumoniae and ESBL-E specimens. CPE was reported in clinical studies and carriage studies past 2010, however a trend could not be determined because of the small dataset. Twelve studies were included in the meta-analysis of risk factors associated with isolation of ESBL. Recent antibiotic exposure was the most studied variable and showed a significant positive association with ESBL-E isolation (pooled OR: 2.9, 95%CI: 2.3-3.8) followed by chronic kidney disease (pooled OR: 4.7, 95%CI: 1.8-11.9), and other co-morbidities (pooled OR: 1.6, 95%CI: 1.2-2.9). Conclusion: Data from GMS is heterogeneous with significant data-gaps, especially in community settings from Laos, Myanmar, Cambodia and Yunnan and Guangxi provinces of China. Collaborative work standardizing the methodology of studies will aid in better monitoring, surveillance and evaluation of interventions across the GMS.

Antimicrobial resistance detection in Southeast Asian hospitals is critically important from both patient and societal perspectives, but what is its cost?

Antimicrobial resistance (AMR) is a major threat to global health. Improving laboratory capacity for AMR detection is critically important for patient health outcomes and population level surveillance. We aimed to estimate the financial cost of setting up and running a microbiology laboratory for organism identification and antimicrobial susceptibility testing as part of an AMR surveillance programme. Financial costs for setting up and running a microbiology laboratory were estimated using a top-down approach based on resource and cost data obtained from three clinical laboratories in the Mahidol Oxford Tropical Medicine Research Unit network. Costs were calculated for twelve scenarios, considering three levels of automation, with equipment sourced from either of the two leading manufacturers, and at low and high specimen throughput. To inform the costs of detection of AMR in existing labs, the unit cost per specimen and per isolate were also calculated using a micro-costing approach. Establishing a laboratory with the capacity to process 10,000 specimens per year ranged from $254,000 to $660,000 while the cost for a laboratory processing 100,000 specimens ranged from $394,000 to $887,000. Excluding capital costs to set up the laboratory, the cost per specimen ranged from $22-31 (10,000 specimens) and $11-12 (100,000 specimens). The cost per isolate ranged from $215-304 (10,000 specimens) and $105-122 (100,000 specimens). This study provides a conservative estimate of the costs for setting up and running a microbiology laboratory for AMR surveillance from a healthcare provider perspective. In the absence of donor support, these costs may be prohibitive in many low- and middle- income country (LMIC) settings. With the increased focus on AMR detection and surveillance, the high laboratory costs highlight the need for more focus on developing cheaper and cost-effective equipment and reagents so that laboratories in LMICs have the potential to improve laboratory capacity and participate in AMR surveillance.

Genotypic and Phenotypic Characterization of Antimicrobial Resistance Profiles in Non-typhoidal Salmonella enterica Strains Isolated From Cambodian Informal Markets

Non-typhoidal Salmonella enterica is a pathogen of global importance, particularly in low and middle-income countries (LMICs). The presence of antimicrobial resistant (AMR) strains in market environments poses a serious health threat to consumers. In this study we identified and characterized the genotypic and phenotypic AMR profiles of 81 environmental S. enterica strains isolated from samples from informal markets in Cambodia in 2018–2019. AMR genotypes were retrieved from the NCBI Pathogen Detection website (https://www.ncbi.nlm.nih.gov/pathogens/) and using ResFinder (https://cge.cbs.dtu.dk/services/) Salmonella pathogenicity islands (SPIs) were identified with SPIFinder (https://cge.cbs.dtu.dk/services/). Susceptibility testing was performed by broth microdilution according to the Clinical and Laboratory Standards Institute (CLSI) standard guidelines M100-S22 using the National Antimicrobial Resistance Monitoring System (NARMS) Sensititre Gram Negative plate. A total of 17 unique AMR genes were detected in 53% (43/81) of the isolates, including those encoding tetracycline, beta-lactam, sulfonamide, quinolone, aminoglycoside, phenicol, and trimethoprim resistance. A total of 10 SPIs (SPI-1, 3–5, 8, 9, 12–14, and centisome 63 [C63PI]) were detected in 59 isolates. C63PI, an iron transport system in SPI-1, was observed in 56% of the isolates (n = 46). SPI-1, SPI-4, and SPI-9 were present in 13, 2, and 5% of the isolates, respectively. The most common phenotypic resistances were observed to tetracycline (47%; n = 38), ampicillin (37%; n = 30), streptomycin (20%; n = 16), chloramphenicol (17%; n = 14), and trimethoprim-sulfamethoxazole (16%; n = 13). This study contributes to understanding the AMR genes present in S. enterica isolates from informal markets in Cambodia, as well as support domestic epidemiological investigations of multidrug resistance (MDR) profiles.

Surveillance strategies using routine microbiology for antimicrobial resistance in low- and middle-income countries

BACKGROUND

Routine microbiology results are a valuable source of antimicrobial resistance (AMR) surveillance data in low- and middle-income countries (LMICs) as well as in high-income countries. Different approaches and strategies are used to generate AMR surveillance data.

OBJECTIVES

We aimed to review strategies for AMR surveillance using routine microbiology results in LMICs and to highlight areas that need support to generate high-quality AMR data.

SOURCES

We searched PubMed for papers that used routine microbiology to describe the epidemiology of AMR and drug-resistant infections in LMICs. We also included papers that, from our perspective, were critical in highlighting the biases and challenges or employed specific strategies to overcome these in reporting AMR surveillance in LMICs.

CONTENT

Topics covered included strategies of identifying AMR cases (including case-finding based on isolates from routine diagnostic specimens and case-based surveillance of clinical syndromes), of collecting data (including cohort, point-prevalence survey, and case-control), of sampling AMR cases (including lot quality assurance surveys), and of processing and analysing data for AMR surveillance in LMICs.

IMPLICATIONS

The various AMR surveillance strategies warrant a thorough understanding of their limitations and potential biases to ensure maximum utilization and interpretation of local routine microbiology data across time and space. For instance, surveillance using case-finding based on results from clinical diagnostic specimens is relatively easy to implement and sustain in LMIC settings, but the estimates of incidence and proportion of AMR is at risk of biases due to underuse of microbiology. Case-based surveillance of clinical syndromes generates informative statistics that can be translated to clinical practices but needs financial and technical support as well as locally tailored trainings to sustain. Innovative AMR surveillance strategies that can easily be implemented and sustained with minimal costs will be useful for improving AMR data availability and quality in LMICs.

Leapfrogging laboratories: the promise and pitfalls of high-tech solutions for antimicrobial resistance surveillance in low-income settings

The scope and trajectory of today’s escalating antimicrobial resistance (AMR) crisis is inadequately captured by existing surveillance systems, particularly those of lower income settings. AMR surveillance systems typically collate data from routine culture and susceptibility testing performed in diagnostic bacteriology laboratories to support healthcare. Limited access to high quality culture and susceptibility testing results in the dearth of AMR surveillance data, typical of many parts of the world where the infectious disease burden and antimicrobial need are high. Culture and susceptibility testing by traditional techniques is also slow, which limits its value in infection management. Here, we outline hurdles to effective resistance surveillance in many low-income settings and encourage an open attitude towards new and evolving technologies that, if adopted, could close resistance surveillance gaps. Emerging advancements in point-of-care testing, laboratory detection of resistance through or without culture, and in data handling, have the potential to generate resistance data from previously unrepresented locales while simultaneously supporting healthcare. Among them are microfluidic, nucleic acid amplification technology and next-generation sequencing approaches. Other low tech or as yet unidentified innovations could also rapidly accelerate AMR surveillance. Parallel advances in data handling further promise to significantly improve AMR surveillance, and new frameworks that can capture, collate and use alternate data formats may need to be developed. We outline the promise and limitations of such technologies, their potential to leapfrog surveillance over currently available, conventional technologies in use today and early steps that health systems could take towards preparing to adopt them.

Microbial Patterns and Antibiotic Susceptibility in Blood Culture Isolates of Septicemia Suspected Children in the Pediatrics Ward of a Tertiary Care Hospital

Objectives  This study aims to determine microbial patterns and antibiotic susceptibility to alert clinicians to the emerging pathogens that may pose a threat to the community, especially children.

Materials and Methods  This retrospective cross-sectional study was conducted in the Department of Pathology, Holy Family Hospital, Rawalpindi, Pakistan, from July 2019 to December 2019. Two samples were taken from two different sites of each patient at the time of fever (> 100° F) to avoid chances of contamination. A blood sample of 5 to 10 mL was drawn from each site. In a 50 mL brain heart infusion broth (BHIB), 5 to 10% blood was injected in two different bottles and incubated for 48 hours at 37°C. After 48 hours, subculture was done by streaking the drops of blood samples taken from BHIB on blood and MacConkey agar. Cultures were incubated in aerobic conditions at 37°C for 24 to 48 hours. For testing antibiotic susceptibility, criteria defined by the Clinical and Laboratory Standards Institute (CLSI) were followed. Microbes were identified under a microscope by observing their morphological characteristics after gram staining and applying biochemical tests. Antibiotic sensitivity test was performed using standard aseptic methods.

Statistical Analysis  Bacterial isolates and their susceptibility patterns were represented using frequencies and percentage charts.

Results  Out of 423 blood cultures, growth was recorded in 92 (21.75%) of the cultures with female to male ratio 2.1:1. The gram-positive bacteria accounted for 43.48% ( n = 40), whereas gram-negative bacteria covered the majority 54.36% ( n = 50). Among isolates, Staphylococcus aureus (42.39%) was the most common, followed by Acinetobacter spp. (17.39%) and Pseudomonas aeruginosa (14.13%). Acinetobacter spp. showed 0% susceptibility to amikacin and cefotaxime. All the isolates were 100% resistant to amoxicillin-clavulanic acid. S. aureus showed lower sensitivity for ceftazidime (0%), clindamycin (66.67%), ciprofloxacin (0%), clarithromycin (11.76%), and ceftriaxone (0%). Tigecycline showed 100% sensitivity for all isolates tested.

Conclusion  Gram-negative bacteria form the majority of isolates in our setup, with Acinetobacter as the most common species among them. The resistance against cephalosporins, penicillin, and fluoroquinolones shown by Acinetobacter , Pseudomonas , Salmonella, and Klebsiella is of grave concern. Among gram-positive bacteria, S. aureus has established resistance against multiple drugs. Limited and objective use of antibiotic therapy is a much-needed strategy under new guidelines.

High burden of infections caused by ESBL-producing MDR Escherichia coli in paediatric patients, Yangon, Myanmar

BACKGROUND

There is mounting evidence of a high burden of antimicrobial-resistant infections in children in low- and middle-income countries (LMICs).

OBJECTIVES

To detect the frequency of ESBL-producing Escherichia coli in clinical specimens from paediatric patients attending Yangon Children's Hospital in Myanmar.

METHODS

All children attending Yangon Children's Hospital who had clinical specimens submitted to the hospital diagnostic microbiology laboratory from June 2019 to December 2019 were included in the study. Specimens were processed routinely using standard methods with BD Phoenix used for pathogen identification and susceptibility testing. Presence of ESBLs was determined using the cephalosporin/clavulanate combination disc method with confirmation by PCR.

RESULTS

From 3462 specimens submitted to the Microbiology Laboratory, a total of 123 E. coli were isolated. Among them, 100 isolates were phenotypically ESBL producers, 94 (76.4%) of which were confirmed by PCR [82/94 (87%) CTX-M, 72/94 (77%) TEM, 1/94 (1%) SHV]. Most of the ESBL-producing E. coli were isolated from urine samples (52.1%, 49/94) and the majority were from the surgical unit (61.7%, 58/94). Only 34/94 (36%) isolates were susceptible to meropenem.

CONCLUSIONS

This study confirms a high proportion of infections caused by ESBL-producing and MDR E. coli in children hospitalized in Yangon, where access to effective second-line antimicrobials is limited.

Prevalence of MDR organism (MDRO) carriage in children and their household members in Siem Reap Province, Cambodia

BACKGROUND

The rising incidence of infections caused by MDR organisms (MDROs) poses a significant public health threat. However, little has been reported regarding community MDRO carriage in low- and middle-income countries.

METHODS

We conducted a cross-sectional study in Siem Reap, Cambodia comparing hospital-associated households, in which an index child (age: 2-14 years) had been hospitalized for at least 48 h in the preceding 2-4 weeks, with matched community households on the same street, in which no other child had a recent history of hospitalization. Participants were interviewed using a survey questionnaire and tested for carriage of MRSA, ESBL-producing Enterobacterales (ESBL-E) and carbapenemase-producing Enterobacterales (CPE) by culture followed by antibiotic susceptibility testing. We used logistic regression analysis to analyse associations between collected variables and MDRO carriage.

RESULTS

Forty-two pairs of households including 376 participants with 376 nasal swabs and 290 stool specimens were included in final analysis. MRSA was isolated from 26 specimens (6.9%). ESBL-producing Escherichia coli was detected in 269 specimens (92.8%) whereas ESBL-producing Klebsiella pneumoniae was isolated from 128 specimens (44.1%), of which 123 (42.4%) were co-colonized with ESBL-producing E. coli. Six (2.1%) specimens tested positive for CPE (4 E. coli and 2 K. pneumoniae). The prevalence ratios for MRSA, ESBL-producing E. coli and ESBL-producing K. pneumoniae carriage did not differ significantly in hospital-associated households and hospitalized children compared with their counterparts.

CONCLUSIONS

The high prevalence of ESBL-E across both household types suggests that MDRO reservoirs are common in the community. Ongoing genomic analyses will help to understand the epidemiology and course of MDRO spread.

Nonautomated Blood Cultures in a Low-Resource Setting: Optimizing the Timing of Blind Subculture

Laboratory procedures for blood cultures in a hospital in Phnom Penh were adapted to optimize detection of Burkholderia pseudomallei, an important pathogen in this setting. The effects of these changes are analyzed in this study. Blood cultures consisted of two BacT/ALERT bottles (bioMérieux, Marcy-l’Etoile, France). Growth was detected visually by daily inspection of the bottles. In 2016, the aerobic–anaerobic pair (FA/FN FAN) was substituted by an aerobic pair of BacT/ALERT FA Plus bottles. Blind subculture (BS) (subculture in the absence of visual growth) was advanced from day 3 to day 2 of incubation in July 2016. In July 2018, it was further advanced to day 1 of incubation. From July 2016 to October 2019, 9,760 blood cultures were sampled. The proportion of cultures showing pathogen growth decreased from 9.6% to 6.8% after the implementation of the laboratory changes (P < 0.001). Advancing the BS from day 3 to day 2 led to an increased proportion of pathogens detected by day 3 (92.8% versus 82.3%; P < 0.001); for B. pseudomallei, this increase was even more remarkable (92.0% versus 18.2%). Blind subculture on day 1 similarly increased the proportion of pathogens detected by day 2 (82.9% versus 69.0% overall, 66.7% versus 10.0% for B. pseudomallei; both P < 0.001). However, after implementation of day 1 subculture, a decrease in recovery of B. pseudomallei was observed (12.4% of all pathogens versus 4.3%; P < 0.001). In conclusion, earlier subculture significantly shortens time to detection and time to actionable results. Some organisms may be missed by performing an early subculture, especially those that grow more slowly.

Antimicrobial Resistance Surveillance in Low- and Middle-Income Countries: Progress and Challenges in Eight South Asian and Southeast Asian Countries

Antimicrobial resistance (AMR) is a serious global health threat and is predicted to cause significant health and economic impacts, particularly in low- and middle-income countries (LMICs). AMR surveillance is critical in LMICs due to high burden of bacterial infections; however, conducting AMR surveillance in resource-limited settings is constrained by poorly functioning health systems, scarce financial resources, and lack of skilled personnel. In 2015, the United Nations World Health Assembly endorsed the World Health Organization's Global Action Plan to tackle AMR; thus, several countries are striving to improve their AMR surveillance capacity, including making significant investments and establishing and expanding surveillance networks. Initial data generated from AMR surveillance networks in LMICs suggest the high prevalence of resistance, but these data exhibit several shortcomings, such as a lack of representativeness, lack of standardized laboratory practices, and underutilization of microbiology services. Despite significant progress, AMR surveillance networks in LMICs face several challenges in expansion and sustainability due to limited financial resources and technical capacity. This review summarizes the existing health infrastructure affecting the establishment of AMR surveillance programs, the burden of bacterial infections demonstrating the need for AMR surveillance, and current progress and challenges in AMR surveillance efforts in eight South and Southeast Asian countries.

Detection of colonisation by extended-spectrum beta-lactamase or carbapenemase producing Enterobacterales from frozen stool specimens

Objective

To determine the impact of pre-culture ultra-low temperature (ULT, − 80 °C) storage of human stool specimens on recovery of Extended-Spectrum Beta-Lactamase (ESBL) or Carbapenemase (CPM) producing Enterobacterales.

Results

Twenty stool specimens from a community-based household colonisation study in Cambodia were cultured fresh and after 4–5 days and ~ 6 months of ULT storage (as a slurry in tryptone soya broth–10% glycerol). Presumptive ESBL- and CPM-Escherichia coli isolates were detected in 19/20 (95%) and 1/20 (5%) freshly cultured specimens, respectively. The specimens yielded identical results when re-cultured after ULT storage at both time points. Detection of presumptive ESBL- and CPM-Klebsiella / Enterobacter / Citrobacter group was less frequent and slightly less stable over time. Comparison of antimicrobial susceptibility test profiles between pairs of E. coli and K. pneumoniae isolates from the two frozen culture time points revealed concordance in only 13/28 (46%) pairs, indicating likely colonisation by multiple strains. In conclusion, ULT storage of human stool specimens prior to culture appears to be an acceptable method for managing laboratory workflow in culture-based ESBL / CPM Enterobacterales colonisation studies in high prevalence settings.

Emerging Resistance to Empiric Antimicrobial Regimens for Pediatric Bloodstream Infections in Malawi (1998-2017)

Background

The adequacy of the World Health Organization’s Integrated Management of Childhood Illness (IMCI) antimicrobial guidelines for the treatment of suspected severe bacterial infections is dependent on a low prevalence of antimicrobial resistance (AMR). We describe trends in etiologies and susceptibility patterns of bloodstream infections (BSI) in hospitalized children in Malawi.

Methods

We determined the change in the population-based incidence of BSI in children admitted to Queen Elizabeth Central Hospital, Blantyre, Malawi (1998–2017). AMR profiles were assessed by the disc diffusion method, and trends over time were evaluated.

Results

A total 89643 pediatric blood cultures were performed, and 10621 pathogens were included in the analysis. Estimated minimum incidence rates of BSI for those ≤5 years of age fell from a peak of 11.4 per 1000 persons in 2002 to 3.4 per 1000 persons in 2017. Over 2 decades, the resistance of Gram-negative pathogens to all empiric, first-line antimicrobials (ampicillin/penicillin, gentamicin, ceftriaxone) among children ≤5 years increased from 3.4% to 30.2% (P < .001). Among those ≤60 days, AMR to all first-line antimicrobials increased from 7.0% to 67.7% (P < .001). Among children ≤5 years, Klebsiella spp. resistance to all first-line antimicrobial regimens increased from 5.9% to 93.7% (P < .001).

Conclusions

The incidence of BSI among hospitalized children has decreased substantially over the last 20 years, although gains have been offset by increases in Gram-negative pathogens’ resistance to all empiric first-line antimicrobials. There is an urgent need to address the broader challenge of adapting IMCI guidelines to the local setting in the face of rapidly-expanding AMR in childhood BSI.

Salmonella Typhi and Paratyphi A infections in Cambodian children, 2012-2016

OBJECTIVES

Enteric fever remains an important diagnostic and treatment challenge in febrile children living in the tropics. In the context of a national Salmonella enterica serovar Paratyphi A outbreak, the objective of this retrospective study was to compare features of S. Typhi and S. Paratyphi A infections in Cambodian children.

METHODS

Clinical and laboratory features were reviewed for 192 blood culture-confirmed children with S. Typhi and S. Paratyphi A infections presenting to a paediatric referral hospital in Siem Reap, 2012-2016.

RESULTS

Children with S. Typhi infections were younger, were more likely to have chills and/or diarrhoea, and were more frequently hospitalized than those with S. Paratyphi A infections. Over three quarters (88.3%) of S. Typhi isolates were multidrug-resistant, compared to none of the S. Paratyphi A.

CONCLUSIONS

In this small study of Cambodian children, S. Typhi infections were more severe than S. Paratyphi A infections. Antibiotic resistance limits treatment options for enteric fever in this population.

ACORN (A Clinically-Oriented Antimicrobial Resistance Surveillance Network): a pilot protocol for case based antimicrobial resistance surveillance

Background: Antimicrobial resistance (AMR) / drug resistant infections (DRIs) are a major global health priority. Surveillance data is critical to inform infection treatment guidelines, monitor trends, and to assess interventions. However, most existing AMR / DRI surveillance systems are passive and pathogen-based with many potential biases. Addition of clinical and patient outcome data would provide considerable added value to pathogen-based surveillance.

Methods: The aim of the ACORN project is to develop an efficient clinically-oriented AMR surveillance system, implemented alongside routine clinical care in hospitals in low- and middle-income country settings. In an initial pilot phase, clinical and microbiology data will be collected from patients presenting with clinically suspected meningitis, pneumonia, or sepsis. Community-acquired infections will be identified by daily review of new admissions, and hospital-acquired infections will be enrolled during weekly point prevalence surveys, on surveillance wards. Clinical variables will be collected at enrolment, hospital discharge, and at day 28 post-enrolment using an electronic questionnaire on a mobile device. These data will be merged with laboratory data onsite using a flexible automated computer script. Specific target pathogens will be Streptococcus pneumoniae, Staphylococcus aureus, Salmonella spp ., Klebsiella pneumoniae, Escherichia coli, and Acinetobacter baumannii. A bespoke browser-based app will provide sites with fully interactive data visualisation, analysis, and reporting tools.

Discussion: ACORN will generate data on the burden of DRI which can be used to inform local treatment guidelines / national policy and serve as indicators to measure the impact of interventions. Following development, testing and iteration of the surveillance tools during an initial six-month pilot phase, a wider rollout is planned.

ACORN (A Clinically-Oriented Antimicrobial Resistance Surveillance Network): a pilot protocol for case based antimicrobial resistance surveillance

Background: Antimicrobial resistance (AMR) / drug resistant infections (DRIs) are a major global health priority. Surveillance data is critical to inform infection treatment guidelines, monitor trends, and to assess interventions. However, most existing AMR / DRI surveillance systems are passive and pathogen-based with many potential biases. Addition of clinical and patient outcome data would provide considerable added value to pathogen-based surveillance. Methods: The aim of the ACORN project is to develop an efficient clinically-oriented AMR surveillance system, implemented alongside routine clinical care in hospitals in low- and middle-income country settings. In an initial pilot phase, clinical and microbiology data will be collected from patients presenting with clinically suspected meningitis, pneumonia, or sepsis. Community-acquired infections will be identified by daily review of new admissions, and hospital-acquired infections will be enrolled during weekly point prevalence surveys, on surveillance wards. Clinical variables will be collected at enrolment, hospital discharge, and at day 28 post-enrolment using an electronic questionnaire on a mobile device. These data will be merged with laboratory data onsite using a flexible automated computer script. Specific target pathogens will be Streptococcus pneumoniae, Staphylococcus aureus, Salmonella spp ., Klebsiella pneumoniae, Escherichia coli, and Acinetobacter baumannii. A bespoke browser-based app will provide sites with fully interactive data visualisation, analysis, and reporting tools. Discussion: ACORN will generate data on the burden of DRI which can be used to inform local treatment guidelines / national policy and serve as indicators to measure the impact of interventions. Following development, testing and iteration of the surveillance tools during an initial six-month pilot phase, a wider rollout is planned.

Impact of 13-Valent Pneumococcal Conjugate Vaccine on Colonization and Invasive Disease in Cambodian Children

BACKGROUND

Cambodia introduced the 13-valent pneumococcal conjugate vaccine (PCV13) in January 2015 using a 3 + 0 dosing schedule and no catch-up campaign. We investigated the effects of this introduction on pneumococcal colonization and invasive disease in children aged <5 years.

METHODS

There were 6 colonization surveys done between January 2014 and January 2018 in children attending the outpatient department of a nongovernmental pediatric hospital in Siem Reap. Nasopharyngeal swabs were analyzed by phenotypic and genotypic methods to detect pneumococcal serotypes and antimicrobial resistance. Invasive pneumococcal disease (IPD) data for January 2012-December 2018 were retrieved from hospital databases. Pre-PCV IPD data and pre-/post-PCV colonization data were modelled to estimate vaccine effectiveness (VE).

RESULTS

Comparing 2014 with 2016-2018, and using adjusted prevalence ratios, VE estimates for colonization were 16.6% (95% confidence interval [CI] 10.6-21.8) for all pneumococci and 39.2% (95% CI 26.7-46.1) for vaccine serotype (VT) pneumococci. There was a 26.0% (95% CI 17.7-33.0) decrease in multidrug-resistant pneumococcal colonization. The IPD incidence was estimated to have declined by 26.4% (95% CI 14.4-35.8) by 2018, with a decrease of 36.3% (95% CI 23.8-46.9) for VT IPD and an increase of 101.4% (95% CI 62.0-145.4) for non-VT IPD.

CONCLUSIONS

Following PCV13 introduction into the Cambodian immunization schedule, there have been declines in VT pneumococcal colonization and disease in children aged <5 years. Modelling of dominant serotype colonization data produced plausible VE estimates.

Longitudinal Assessment of Antibiotic Resistance in Fecal Escherichia coli in Tanzanian Children

Antibiotic-resistant bacterial infections are a major public health problem, and children in low-resource settings represent a particularly high-risk group. Few data are available on the dynamics of and risk factors for gastrointestinal carriage of antibiotic-resistant bacteria in these vulnerable populations. In this study, we described the antibiotic susceptibility profiles of Escherichia coli isolated from stool specimens collected from children aged 6 to 60 months enrolled in a birth cohort study in Haydom, Tanzania. We estimated the association between sociodemographic risk factors, child illnesses, and antibiotic exposure and E. coli drug resistance. Carriage of antibiotic-resistant E. coli was common starting early in life and did not clearly increase with age. The majority of isolates were resistant to ampicillin (749/837; 89.5%), cefazolin (742/837; 88.6%), and cotrimoxazole (721/837; 86.1%). Resistance to amoxicillin/clavulanate (361/836; 43.2%), ampicillin/sulbactam (178/819; 21.7%), nalidixic acid (131/831; 15.8%), and azithromycin (115/837; 13.7%) was also seen. Only 1.8% (15/837) of the pooled E. coli isolates met the criteria for extended-spectrum beta-lactamase production. High antibiotic use (0.26 additional resistant antibiotic classes; 95% CI: 0.05, 0.47) and high income (0.28 additional resistant antibiotic classes; 95% CI: 0.06, 0.50) were associated with the carriage of antibiotic-resistant E. coli, whereas hospital birth, crowding in the home, improved drinking water and sanitation, and common childhood illnesses were not. In this setting, the carriage of antibiotic-resistant E. coli was common. Other than recent antibiotic exposure and high income, individual risk factors for the acquisition and carriage of resistance could not be identified, suggesting that population-level interventions are needed.

Genomic surveillance for hypervirulence and multi-drug resistance in invasive Klebsiella pneumoniae from South and Southeast Asia

BACKGROUND

Klebsiella pneumoniae is a leading cause of bloodstream infection (BSI). Strains producing extended-spectrum beta-lactamases (ESBLs) or carbapenemases are considered global priority pathogens for which new treatment and prevention strategies are urgently required, due to severely limited therapeutic options. South and Southeast Asia are major hubs for antimicrobial-resistant (AMR) K. pneumoniae and also for the characteristically antimicrobial-sensitive, community-acquired "hypervirulent" strains. The emergence of hypervirulent AMR strains and lack of data on exopolysaccharide diversity pose a challenge for K. pneumoniae BSI control strategies worldwide.

METHODS

We conducted a retrospective genomic epidemiology study of 365 BSI K. pneumoniae from seven major healthcare facilities across South and Southeast Asia, extracting clinically relevant information (AMR, virulence, K and O antigen loci) using Kleborate, a K. pneumoniae-specific genomic typing tool.

RESULTS

K. pneumoniae BSI isolates were highly diverse, comprising 120 multi-locus sequence types (STs) and 63 K-loci. ESBL and carbapenemase gene frequencies were 47% and 17%, respectively. The aerobactin synthesis locus (iuc), associated with hypervirulence, was detected in 28% of isolates. Importantly, 7% of isolates harboured iuc plus ESBL and/or carbapenemase genes. The latter represent genotypic AMR-virulence convergence, which is generally considered a rare phenomenon but was particularly common among South Asian BSI (17%). Of greatest concern, we identified seven novel plasmids carrying both iuc and AMR genes, raising the prospect of co-transfer of these phenotypes among K. pneumoniae.

CONCLUSIONS

K. pneumoniae BSI in South and Southeast Asia are caused by different STs from those predominating in other regions, and with higher frequency of acquired virulence determinants. K. pneumoniae carrying both iuc and AMR genes were also detected at higher rates than have been reported elsewhere. The study demonstrates how genomics-based surveillance-reporting full molecular profiles including STs, AMR, virulence and serotype locus information-can help standardise comparisons between sites and identify regional differences in pathogen populations.

Genomic surveillance for hypervirulence and multi-drug resistance in invasive Klebsiella pneumoniae from South and Southeast Asia

BACKGROUND

Klebsiella pneumoniae is a leading cause of bloodstream infection (BSI). Strains producing extended-spectrum beta-lactamases (ESBLs) or carbapenemases are considered global priority pathogens for which new treatment and prevention strategies are urgently required, due to severely limited therapeutic options. South and Southeast Asia are major hubs for antimicrobial-resistant (AMR) K. pneumoniae and also for the characteristically antimicrobial-sensitive, community-acquired "hypervirulent" strains. The emergence of hypervirulent AMR strains and lack of data on exopolysaccharide diversity pose a challenge for K. pneumoniae BSI control strategies worldwide.

METHODS

We conducted a retrospective genomic epidemiology study of 365 BSI K. pneumoniae from seven major healthcare facilities across South and Southeast Asia, extracting clinically relevant information (AMR, virulence, K and O antigen loci) using Kleborate, a K. pneumoniae-specific genomic typing tool.

RESULTS

K. pneumoniae BSI isolates were highly diverse, comprising 120 multi-locus sequence types (STs) and 63 K-loci. ESBL and carbapenemase gene frequencies were 47% and 17%, respectively. The aerobactin synthesis locus (iuc), associated with hypervirulence, was detected in 28% of isolates. Importantly, 7% of isolates harboured iuc plus ESBL and/or carbapenemase genes. The latter represent genotypic AMR-virulence convergence, which is generally considered a rare phenomenon but was particularly common among South Asian BSI (17%). Of greatest concern, we identified seven novel plasmids carrying both iuc and AMR genes, raising the prospect of co-transfer of these phenotypes among K. pneumoniae.

CONCLUSIONS

K. pneumoniae BSI in South and Southeast Asia are caused by different STs from those predominating in other regions, and with higher frequency of acquired virulence determinants. K. pneumoniae carrying both iuc and AMR genes were also detected at higher rates than have been reported elsewhere. The study demonstrates how genomics-based surveillance-reporting full molecular profiles including STs, AMR, virulence and serotype locus information-can help standardise comparisons between sites and identify regional differences in pathogen populations.

Transmission dynamics and control of multidrug-resistant Klebsiella pneumoniae in neonates in a developing country

Multidrug-resistant Klebsiella pneumoniae is an increasing cause of infant mortality in developing countries. We aimed to develop a quantitative understanding of the drivers of this epidemic by estimating the effects of antibiotics on nosocomial transmission risk, comparing competing hypotheses about mechanisms of spread, and quantifying the impact of potential interventions. Using a sequence of dynamic models, we analysed data from a one-year prospective carriage study in a Cambodian neonatal intensive care unit with hyperendemic third-generation cephalosporin-resistant K. pneumoniae. All widely-used antibiotics except imipenem were associated with an increased daily acquisition risk, with an odds ratio for the most common combination (ampicillin + gentamicin) of 1.96 (95% CrI 1.18, 3.36). Models incorporating genomic data found that colonisation pressure was associated with a higher transmission risk, indicated sequence type heterogeneity in transmissibility, and showed that within-ward transmission was insufficient to maintain endemicity. Simulations indicated that increasing the nurse-patient ratio could be an effective intervention.

Prevalence and time trend analysis of antimicrobial resistance in respiratory bacterial pathogens collected from diseased pigs in USA between 2006-2016

Swine respiratory disease complex (SRDC) causes massive economic losses to the swine industry and is a major animal welfare concern. Antimicrobials are mainstay in treatment and control of SRDC. However, there is a lack of data on the prevalence and trends in resistance to antimicrobials in bacterial pathogens associated with SRDC. The objective of this study was to estimate the prevalence and changes in resistance to 13 antimicrobials in swine bacterial pathogens (Streptococcus suis, Pasteurella multocida, Actinobacillus suis and Haemophilus parasuis) in the U.S.A using data collected at University of Minnesota Veterinary Diagnostic Laboratory between 2006 and 2016. For antimicrobials for which breakpoints were available, prevalence of resistance remained below 10% except for tetracycline in S. suis and P. multocida isolates, and these prevalence estimates remained consistently low over the years despite statistical significance (p < .05) in trend analysis. For antimicrobial-bacterial combinations without available breakpoints, the odds of isolates being resistant increased by >10% annually for 7 and 1 antimicrobials in H. parasuis and S. suis isolates respectively, and decreased >10% annually for 4 and 1 antimicrobials in A. suis and H. parasuis isolates, respectively, according to the ordinal regression models. Clinical implications of changes in AMR for A. suis and H. parasuis should be interpreted cautiously due to the lack of interpretive criteria and challenges in antimicrobial susceptibility tests in the case of H. parasuis. Future studies should focus on surveillance of antimicrobial resistance and establishment of standardized susceptibility testing methodologies and interpretive criteria for these animal pathogens of critical importance.

Meat and Fish as Sources of Extended-Spectrum β-Lactamase-Producing Escherichia coli, Cambodia

We compared extended-spectrum β-lactamase-producing Escherichia coli isolates from meat and fish, gut-colonized women, and infected patients in Cambodia. Nearly half of isolates from women were phylogenetically related to food-origin isolates; a subset had identical multilocus sequence types, extended-spectrum β-lactamase types, and antimicrobial resistance patterns. Eating sun-dried poultry may be an exposure route.

Antimicrobial resistance in Cambodia: a review

OBJECTIVES

Following the launch of the Global Antimicrobial Resistance Surveillance System (GLASS), antimicrobial resistance (AMR) rates in many countries remain poorly described. This review provides an overview of published AMR data from Cambodia in the context of recently initiated national human and food-animal surveillance.

METHODS

PubMed and the Cochrane Database of Systematic Reviews were searched for articles published from 2000 to 2018, which reported antimicrobial susceptibility testing (AST) data for GLASS specific organisms isolated from Cambodia. Articles were screened using strict inclusion/exclusion criteria. AST data was extracted, with medians and ranges of resistance rates calculated for specific bug-drug combinations.

RESULTS

Twenty-four papers were included for final analysis, with 20 describing isolates from human populations. Escherichia coli was the most commonly described organism, with median resistance rates from human isolates of 92.8% (n=6 articles), 46.4% (n=4), 55.4% (n=8), and 46.4% (n=5) to ampicillin, 3^rd generation cephalosporins, fluoroquinolones, and gentamicin respectively.

CONCLUSIONS

Whilst resistance rates are high for several GLASS organisms, there were insufficient data to draw robust conclusions about the AMR situation in Cambodia. The recently implemented national AMR surveillance systems will begin to address this data gap.

Microbiology Investigation Criteria for Reporting Objectively (MICRO): a framework for the reporting and interpretation of clinical microbiology data

BACKGROUND

There is a pressing need to understand better the extent and distribution of antimicrobial resistance on a global scale, to inform development of effective interventions. Collation of datasets for meta-analysis, mathematical modelling and temporo-spatial analysis is hampered by the considerable variability in clinical sampling, variable quality in laboratory practice and inconsistencies in antimicrobial susceptibility testing and reporting.

METHODS

The Microbiology Investigation Criteria for Reporting Objectively (MICRO) checklist was developed by an international working group of clinical and laboratory microbiologists, infectious disease physicians, epidemiologists and mathematical modellers.

RESULTS

In keeping with the STROBE checklist, but applicable to all study designs, MICRO defines items to be included in reports of studies involving human clinical microbiology data. It provides a concise and comprehensive reference for clinicians, researchers, reviewers and journals working on, critically appraising, and publishing clinical microbiology datasets.

CONCLUSIONS

Implementation of the MICRO checklist will enhance the quality and scientific reporting of clinical microbiology data, increasing data utility and comparability to improve surveillance, grade data quality, facilitate meta-analyses and inform policy and interventions from local to global levels.

Deciphering risk factors for blood stream infections, bacteria species and antimicrobial resistance profiles among children under five years of age in North-Western Tanzania: a multicentre study in a cascade of referral health care system

BACKGROUND

Blood stream infections (BSIs) cause a complex cascade of inflammatory events, resulting in significant morbidity and mortality in children in Tanzania. This study was designed to delineate circulating bacterial species, antimicrobial resistance (AMR) profiles and risk factors for BSIs and mortality among children in the cascade of referral health care facilities so as to guide comprehensive BSIs management.

METHODS

A multiple cross sectional analytical study was conducted between July 20, 2016 to October 04, 2017 involving 950 children less than five years of age in the North-western part of Tanzania. Children with clinical features suggestive of BSIs were included. Demographic, clinical and laboratory information on culture and antimicrobial susceptibility testing was collected from children; and analyzed using STATA version 13.0 software.

RESULTS

The prevalence of BSIs among children was 14.2% (95% CI: 12.1-16.6%), with specific prevalence in the district, regional and tertiary hospitals being 8.3, 6.4 and 20.0%, respectively. The most common bacterial pathogens isolated from 135 culture-positive children were Klebsiella pneumoniae (55, 40.4%), Staphylococcus aureus (23, 17.0%), and Escherichia coli (17, 12.6%). Multi-drug resistance (MDR) was higher in isolates from children at Bugando Medical Centre (BMC) tertiary hospital than isolates from district and regional hospitals [OR (95% CI): 6.36 (2.15-18.76); p = 0.001]. Independent risk factors for BSIs were neonatal period [OR (95% CI): 1.93 (1.07-3.48); p = 0.003] and admission at BMC [2.01 (1.08-3.74); p = 0.028)]. Approximately 6.6% (61/932) of children died, and risk factors for mortality were found to be children attending BMC [OR (95% CI): 4.95 (1.95-12.5); p = 0.001)], neonatal period [OR (95% CI): 2.25 (1.02-5.00); p = 0.045)], and children who had blood culture positive results [OR (95% CI): 1.95 (1.07-3.56); p = 0.028)].

CONCLUSIONS

The prevalence of BSIs (14.2%) in this multi-centre study is high and predominantly caused by the MDR K. pneumoniae. Priority interventional measures to combat BSIs and mortality, specifically among neonates at BMC are urgently recommended.

Using machine learning to guide targeted and locally-tailored empiric antibiotic prescribing in a children's hospital in Cambodia

Background: Early and appropriate empiric antibiotic treatment of patients suspected of having sepsis is associated with reduced mortality. The increasing prevalence of antimicrobial resistance reduces the efficacy of empiric therapy guidelines derived from population data. This problem is particularly severe for children in developing country settings. We hypothesized that by applying machine learning approaches to readily collect patient data, it would be possible to obtain individualized predictions for targeted empiric antibiotic choices. Methods and Findings: We analysed blood culture data collected from a 100-bed children's hospital in North-West Cambodia between February 2013 and January 2016. Clinical, demographic and living condition information was captured with 35 independent variables. Using these variables, we used a suite of machine learning algorithms to predict Gram stains and whether bacterial pathogens could be treated with common empiric antibiotic regimens: i) ampicillin and gentamicin; ii) ceftriaxone; iii) none of the above. 243 patients with bloodstream infections were available for analysis. We found that the random forest method had the best predictive performance overall as assessed by the area under the receiver operating characteristic curve (AUC). The random forest method gave an AUC of 0.80 (95%CI 0.66-0.94) for predicting susceptibility to ceftriaxone, 0.74 (0.59-0.89) for susceptibility to ampicillin and gentamicin, 0.85 (0.70-1.00) for susceptibility to neither, and 0.71 (0.57-0.86) for Gram stain result. Most important variables for predicting susceptibility were time from admission to blood culture, patient age, hospital versus community-acquired infection, and age-adjusted weight score. Conclusions: Applying machine learning algorithms to patient data that are readily available even in resource-limited hospital settings can provide highly informative predictions on antibiotic susceptibilities to guide appropriate empiric antibiotic therapy. When used as a decision support tool, such approaches have the potential to improve targeting of empiric therapy, patient outcomes and reduce the burden of antimicrobial resistance.