Underdiagnosis in clinical documentation of community-acquired sepsis among children admitted to hospitals in two rural provinces: Thailand, October-December 2017

Paediatric sepsis prevalence data from low-income and middle-income countries are lacking. In a cross-sectional study, we assessed clinician recognition and documentation of non-neonatal community-acquired paediatric sepsis in two rural border provinces in Thailand among children admitted between October and December 2017. Of the 152 children meeting sepsis criteria (26.9 paediatric sepsis patients per 1000 admissions), 15 (9.9%) had a clinician-documented admission diagnosis of sepsis or septic shock and 18 (11.8%) had a discharge diagnosis with International Classification of Diseases-10 codes related to sepsis. Clinician underdocumentation may cause challenges in global paediatric sepsis surveillance.

Chronic Wound Infection Model of Acinetobacter baumannii in Outbred Mice

INTRODUCTION

We established a murine wound infection model with doxycycline treatment against multidrug-resistant Acinetobacter baumannii (AB5075) in Institute of Cancer Research (ICR) outbred mice.

METHODS

Using three groups of neutropenic ICR mice, two full-thickness dorsal dermal wounds (6 mm diameter) were made on each mouse. In two groups, wounds were inoculated with 7.0 × 104 colony-forming units of AB5075. Of these two groups, one received a 6-day regimen of doxycycline while the other was sham treated with phosphate-buffered saline as placebo control. Another uninfected/untreated group served as a control. Wound closure, clinical symptoms, bacterial burden in wound beds and organs, and wound histology were investigated.

RESULTS

Doxycycline-treated wounds completely healed by day 21, but untreated, infected wounds failed to heal. Compared to controls, wound infections without treatment resulted in significant reductions in body weight and higher bacterial loads in wound beds, lung, liver, and spleen by day 7. Histological evaluation of wounds on day 21 revealed ulcerated epidermis, muscle necrosis, and bacterial presence in untreated wounds, while wounds treated with doxycycline presented intact epidermis.

CONCLUSIONS

Compared to the previously developed BALB/c dermal wound model, this study demonstrates that the mouse strain selected impacts wound severity and resolution. Furthermore, this mouse model accommodates two dorsal wounds rather than only one. These variations offer investigators increased versatility when designing future studies of wound infection. In conclusion, ICR mice are a viable option as a model of dermal wound infection. They accommodate two simultaneous dorsal wounds, and upon infection, these wounds follow a different pattern of resolution compared to BALB/c mice.

Antimicrobial Susceptibility of Neisseria gonorrhoeae in Adult Patients Seeking Care at Military Hospitals in Thailand From 2014 to 2020

INTRODUCTION

The effective dual antibiotics ceftriaxone (CRO) and azithromycin (AZM) have successfully treated Neisseria gonorrhoeae (GC) infection, however, the CRO- and AZM-resistant strains have been sporadically detected globally and in Thailand. Furthermore, there are no currently antimicrobial susceptibility profiles of the GC isolates obtained from soldiers reported in Thailand. Hence, this is the first study to describe the antimicrobial susceptibility profiles of GC isolates obtained from predominately soldiers who seeking care at Military Camp Hospitals, in Thailand from 2014 to 2020.

MATERIALS AND METHODS

A total of 624 symptomatic gonococcal samples were received from 10 military hospitals during 2014-2020. They were collected from urethral swabs and inoculated into selective media. The suspected GC isolates were subcultured and presumptively identified using conventional microbiology techniques. Antimicrobial susceptibility test was performed by Etest to determine minimal inhibitory concentration (μg/mL) against AZM, benzylpenicillin, cefepime, cefixime, ceftriaxone (CRO), ciprofloxacin, spectinomycin, and tetracycline using the criteria outlined in the Clinical and Laboratory Standards Institute guidelines. This study was approved by Institutional Review Board, Royal Thai Army Medical Department under protocol number S036b/56 and Walter Reed Army Institute of Research, and Silver Spring, MD under protocol number WR #2039.

RESULTS

A total of 624 samples were collected from symptomatic gonococcal infectious patients with 91.5% (571/624) of samples obtained from soldiers. Of those, 78% (488/624) were identified as GC and 92% (449/488) of them were isolated from soldiers. All GC samples collected were susceptible to CRO (first-line treatment) with only one GC isolate identified as non-susceptible to cefepime and three isolates identified as non-susceptible to AZM.

CONCLUSION

The recommended dual treatment of GC infections with CRO and AZM is currently an effective empirical treatment for patients who are seeking care at military hospitals in Thailand. Nevertheless, cefepime is a fourth-generation cephalosporin with documented high activity against GC strains equal to other "third-generation" cephalosporins such as CRO. Due to the active duty of military personnel, they concerned about the confidentiality and frequently seek treatment at civilian clinics. Additionally, due to the availability of antibiotics over the counter in Thailand, many choose the option to self-medicate without a physician's prescription. These could be subsequently driven the gradual increase of multidrug-resistant gonococcal strains throughout the country. Thus, the GC surveillance would be needed for further Force Health Protection and public health authorities in response to the drug-resistant GC threats.

First Report: Colistin Resistance Gene mcr-3.1 in Salmonella enterica Serotype Choleraesuis Isolated from Human Blood Sample from Thailand

This study describes the first finding of Salmonella enterica serotype Choleraesuis (Salmonella Choleraesuis) isolate harboring mobile colistin resistance (mcr)-3.1 obtained from human blood sample. The clinical relevant blood sample was collected during October 2018. The phenotypic identification and antimicrobial susceptibility testing (AST) were studied by using automate microbiology platform (Phoenix M50, BD), and in-depth characterization by whole genome sequencing. The phenotypic identification was reported Salmonella Choleraesuis. AST result demonstrated that this isolate had high minimum inhibitory concentrations (MICs) against colistin, fluoroquinolone, and cephalosporin III and IV, which are first-line antibiotic treatment choices for Gram-negative bacterial pathogen infections. This Salmonella Choleraesuis is harboring mcr-3.1 and presented a diversity carbapenemase including bla_TEM and bla_ctx-m-55. Regarding the multilocus sequence typing result, this Salmonella presented ST139 that related to the Choleraesuis variant sensu stricto. Swine is not the host specific for the Salmonella Choleraesuis since it also causes enteric and other diseases in human. Hence, the presence of the mobile plasmid colistin mcr-3.1 resistant gene in human sample is resulting to the public health concerns due to the fact that it is enable to transmit to other hosts and distribute into an environment.

Travelers' Diarrhea in Thailand: A Quantitative Analysis Using TaqMan® Array Card

Background

Travelers' diarrhea (TD) is a common illness experienced by travelers from developed countries who visit developing countries. Recent questionnaire-based surveillance studies showed that approximately 6%-16% of travelers experienced TD while visiting Thailand; however, a majority of TD information was limited mainly to US military populations.

Methods

A TD surveillance study was conducted at Bumrungrad International Hospital in 2012-2014 in Bangkok, Thailand. Enteropathogens were identified using conventional methods and the TaqMan® array card (TAC), which uses real-time polymerase chain reaction for the simultaneous detection of multiple pathogens. Analyses to determine pathogen-disease and symptoms association were performed to elucidate the clinical relevance of each enteropathogen.

Results

TAC identified more pathogens per sample than conventional methods. Campylobacter spp. were the most prevalent, followed by the diarrheagenic Escherichia coli and norovirus GII. These agents had significant pathogen-disease associations as well as high attributable fractions among diarrheal cases. A wide range of pathogen loads for Campylobacter spp. was associated with TD, while heat-labile toxin enterotoxigenic Escherichia coli was associated with an increased pathogen load. Most cases were associated with inflammatory diarrhea, while Campylobacter spp. and Shigella spp. were associated with dysentery.

Conclusions

A pan-molecular diagnostic method such as TAC produces quantifiable and comparable results of all tested pathogens, thereby reducing the variability associated with multiple conventional methods. This allows better determination of the clinical relevance of each diarrhea etiologic agent, as well as their geographical relevance in Thailand.

Determination of azithromycin heteroresistant Campylobacter jejuni in traveler's diarrhea

Campylobacter is the most common cause of traveler's diarrhea (TD) and human bacterial gastroenteritis. A heteroresistant Campylobacter jejuni (C. jejuni) isolate, identified by microbiological methods and characterized with molecular techniques, was obtained from a traveler in Nepal suffering TD. The presence of atypical colonies within the clear zone of inhibition was the first evidence of an atypical phenotype, leading to additional characterization of this heteroresistant strain. Antimicrobial susceptibility testing (AST) and population analysis profiling (PAP) demonstrated heteroresistance to azithromycin (AZM), a first-line antibiotic treatment for Campylobacter infections. Molecular analysis indicated a point mutation occurred on the 23S rRNA gene at the A2075G transitions, and the number of mutated gene copies was proportional to AZM resistance. Heteroresistant C. jejuni subpopulations from acute TD are likely underestimated, which may lead to treatment failures, as was the case for this patient. The presence of a heteroresistant strain in a high antibiotic environment may select for additional drug resistance and enable distribution into hospital and local communities.

Antimicrobial resistant Helicobacter fennelliae isolated from non-diarrheal child stool sample in Battambang, Cambodia

Helicobacter fennelliae (H. fennelliae) is associated with human gastroenteritis; however, H. fennelliae was isolated and confirmed by phenotypic and genotypic identification from a non-diarrheal child stool sample in Cambodia. Antimicrobial susceptibility testing demonstrated that this isolate had a high minimal inhibitory concentration against macrolides and quinolones, which are first-line antibiotic treatment choices for Campylobacter infections. Consequently, macrolides and quinolones were likewise expected to be ineffective against Campylobacter-like organisms such as H. fennelliae. This isolate warranted further genetic characterization to better understand associated antibiotic resistance mechanisms. Resistant pathogens from asymptomatic diarrheal cases are likely underestimated, and as such colonized individuals may spread resistant organisms to local community members and the environment.

Multidrug-Resistant Shigella Infections in Patients with Diarrhea, Cambodia, 2014-2015

We observed multidrug resistance in 10 (91%) of 11 Shigella isolates from a diarrheal surveillance study in Cambodia. One isolate was resistant to fluoroquinolones and cephalosporins and showed decreased susceptibility to azithromycin. We found mutations in gyrA, parC, β-lactamase, and mphA genes. Multidrug resistance increases concern about shigellosis treatment options.

Development of an Orientia tsutsugamushi Lc-1 Murine Intraperitoneal Challenge Model for Scrub Typhus: Determination of Murine Lethal Dose (MuLD50), Tissue Bacterial Loads, and Clinical Outcomes

Currently, no vaccine has been developed to protect humans from naturally acquired heterologous Orientia tsutsugamushi infections. To enhance the validity of vaccine candidates, we are developing a murine chigger challenge model with the O. tsutsugamushi Lc-1-infected Leptotrombidium chiangraiensis Line-1. To this end, an intraperitoneal (i.p.) murine challenge model using an O. tsutsugamushi Lc-1 isolate was developed for eventual validation of the chigger challenge model. We have determined that the murine lethal dose that kills 50% of the challenged mice (MuLD50) of a liver/spleen homogenate developed from O. tsutsugamushi Lc-1-infected ICR Swiss mice to be 10(-6.9). Employing different inoculum doses of this homogenate, the bacterial load using quantitative real-time PCR (qPCR) was determined to range from 60 to 1.6 × 10(5) genome equivalent copies (GEC)/μL of liver and 33.4 to 2.2 × 10(5) GEC/μL of spleen tissue. The clinical outcomes relative to homogenate dose levels followed a dose-dependent pattern. The successful development and characterization of the O. tsutsugamushi Lc-1 i.p. challenge model will assist in the development and validation of a mouse chigger challenge scrub typhus model.

Establishment of Orientia tsutsugamushi Lc-1 (Rickettsiales: Rickettsiaceae) infection in ICR outbred mice (Rodentia: Muridae) by needle challenge

Orientia tsutsugamushi is a pathogen transmitted by Leptotrombidium that causes scrub typhus. To develop an infection mouse model, a mite-derived isolate of O. tsutsugamushi was established from a laboratory-maintained colony of Leptotrombidium chiangraiensis (O. tsutsugamushi Lc-1). This Lc-1 isolate was initially presented to ICR (CD-1) mice by feeding an infected Lc chigger on the ear of a mouse. Once the Lc-1 was adapted to the ICR mice, quantitative real-time polymerase chain reaction was used to investigate O. tsutsugamushi genomic equivalent copies in tissues and sera. Furthermore, times to onset of the signs of infection are reported in this study. This study provides information useful for future research on this host-pathogen interaction and the associated vaccine efficacy trials.

Variable clinical responses of a scrub typhus outbred mouse model to feeding by Orientia tsutsugamushi infected mites

Rodents are the natural hosts for Leptotrombidium mites that transmit Orientia tsutsugamushi, the causative agent of scrub typhus, a potentially fatal febrile human disease. Utilizing mite lines that included O. tsutsugamushi infected and non-infected Leptotrombidium species we investigated the varied infection response of outbred mice (ICR) exposed to L. chiangraiensis (Lc), L. imphalum (Li) and L. deliense (Ld). Each of six mite lines (Lc1, Lc5, Li3, Li4, Li7 and Ld) was separately placed in the inner ears of ICR mice either as a single individual (individual feeding, IF) or as a group of 2-4 individuals (pool feeding, PF). The species of infected chigger feeding on mice significantly affected mortality rates of the mice, with mite lines of Lc causing higher mean (±SE) mortality (90.7 ± 3.6 %) than mite lines of Li (62.9 ± 5.6 %) or Ld (53.6 ± 5.8 %). Mouse responses which included time to death, food consumption and total mice weight change depended on mite species and their O. tsutsugamushi genotype, more than on feeding procedure (IF vs. PF) except for mite lines within the Lc. Infected mite lines of Lc were the most virulent infected mites assessed whereas the infected Ld species was the least virulent for the ICR. Mice killed by various mite lines showed enlarged spleens and produced ascites. The results of this investigation of the clinical responses of ICR mice to feeding by various infected mite lines indicated that the different species of infected mites and their O. tsutsugamushi genotype produced different clinical presentations in ICR mice, a scrub typhus mouse model which mimics the natural transmission of O. tsutsugamushi that is critical for understanding scrub typhus disease in terms of natural transmission, host-pathogen-vector interaction and vaccine development.

Human papillomavirus genotypes among infected Thai women with different cytological findings by analysis of E1 genes

Cervical cytological data may not be sufficient for cervical cancer screening and prevention. In this project, we determined HPV genotype among infected Thai women with different cytological findings by characterization of E1 genes. Five hundred and thirty-five specimens were tested by PCR amplification of the E1 genes. HPV genotypes were determined by sequencing, comparison with the GenBank database and were analyzed in relation to different cytological findings. HPV-DNA by PCR were typed and revealed 32 different genotypes. HR-HPV (HPV16, 18 or 52) was detected in all samples with cervical cancer cytology. HPV16 was most prevalent irrespective of cervical cytology. Moreover, HPV31 and 52 were most prevalent in the HSIL and LSIL groups whereas HPV66 was found mostly in the LSIL group. The LSIL group displayed the highest variation of HPV genotypes. Moreover, HPV31 and 52 predominated in the HSIL and LSIL groups especially HPV52 which was found in cancer samples. We hoped that these data of HPV genotypes can be used as preliminary data of HPV in Thailand and can serve as basic data for future research into the HPV genotype in south-east Asia.

Prevalence and genotypes of human papillomavirus among Thai women

One of the most common cancers in women worldwide is cervical cancer, with death rates highest in less developed countries, including Thailand. This study was conducted to explore the prevalence of human papillomavirus (HPV) and its related cytological abnormalities among women attending cervical screening clinics in Thailand using the polymerase chain reaction (PCR). LBC specimens (ThinPrep, Hologic, West Sussex, UK) were subjected to PCR of the E1 region to identify the most prevalent HPV types. Information on age and cytology grade was also collected. Among a total of 1,662 women, 29 different HPV types were found and the overall HPV prevalence was 8.7%. HPV prevalence among the general population amounted to 7.8%. The following HPV types were identified: HPV16 (17.9%), HPV90 (16.6%) and HPV71 (10.3%). The rates of other types were as follows; HPV66 (6.9%), HPV52 (6.2%), HPV34 (5.5%), HPV31 (5.3%), HPV42 (4.8%) and HPV39 (3.4%). HPV infection peaked in women aged around 20-39 years and thereafter gradually declined. As expected, HPV DNA can be found in normal cytology specimens. These results which elucidate HPV distribution in Thailand could be useful for vaccine development and the national cervical cancer prevention program.

Relationship between hybrid capture II ratios and DNA amplification of E1, E6 and L1 genes used for the detection of human papillomavirus in samples with different cytological findings

The hybrid capture II (HCII) assay is widely used in the detection of human papillomavirus virus (HPV). However, due to the limited number of HPV genotypes, it does not permit a comprehensive typing of viruses and "grey zone" (borderline negative or positive results) are often difficult to interpret. As such, polymerase chain reaction (PCR) should be used in parallel with HCII assays, and consensus PCR detection is capable of covering a wider detection range than with the HCII method. We examined the relationship between HCII relative light unit/cutoff (RLU/CO) ratios and PCR amplification results. This was done using previously described primer sets (MY/GP) as well as with our primers for HPV E1, L1 and E6 gene amplification, and performed on samples exhibiting different cytological findings. Together, 243 samples were divided into three groups having RLU/CO ratios of < 0.4 (n = 21), 0.4-4 (n = 64) and > or = 4 (n = 158), respectively. All samples were subjected to PCR amplification using MY/GP and the newly designed E1, L1 and E6 primers. Results were verified by direct sequencing. PCR amplification sensitivities were higher when using the E1 primers than for the MY/GP, E6 or L1 primers. The E1 assay can be used for HPV detection with a sensitivity of 10(2) copies microl(-1). Samples with RLU/CO ratios exceeding 4, and grey zone samples of 0.4-4, were amplified using E1 primers in 79.74% and 26.56% of the total cases, respectively. Cytological data of grey zone samples were primarily found to be normal (77%) whereas those with RLU/CO ratios > 4 were found in any of the cytological data categories. We concluded that HPV screening by HCII for grey zone samples should be analyzed together with cytological data, as well as with a PCR screening tool that incorporates the E1 primers.

Entire genome characterization of human papillomavirus type 16 from infected Thai women with different cytological findings

Global prevalence of human papillomavirus type 16 (HPV16) exceeds that of other types. This project has been aimed at attaining basic molecular knowledge of HPV16 by sequencing the whole genome of HPV16 isolated from Thai women at various clinical stages of disease progression. Our group analyzed seven samples of HPV16 in infected women ranging from normal to cervical cancer and discovered two critical non-synonymous changes within the coding region converting the E2-219P prototype to E2-219T in cervical cancer and the L2-269S prototype to L2-269D in CIN III, respectively. Phylogenetic analysis based on the whole genome with special emphasis on the genes E2, E6, L1, and L2 showed the Thai samples to be more closely related to the European than the non-European strains. The vaccine strain's L1 polypeptides showed close relationship to our samples. The results provide basic data for future research on cervical cancer pathogenesis and representative data of HPV16 genome in Southeast Asia.

Rapid detection and strain identification of porcine reproductive and respiratory syndrome virus (PRRSV) by real-time RT-PCR

AIMS

To develop and validate assays based on real-time reverse transcriptase-polymerase chain reaction (RT-PCR) for rapid detection and strain identification (European and North American strains) of porcine reproductive and respiratory syndrome virus (PRRSV) by using SYBR Green I and TaqMan probe chemistries.

METHODS AND RESULTS

This study describes two alternative assays based on real-time RT-PCR for rapid detection and strain identification of PRRSV in comparison with conventional RT-PCR. The first assay utilized SYBR Green I with melting curve analysis; another assay was performed using strain-specific TaqMan probes. Primers were selected from the conserved regions within ORF7 (N) of both strains whereas two TaqMan probes labelled with different fluorescent dyes were specifically designed for each strain. The result of strain identification was confirmed by direct sequencing. Both assays can be used for rapid detection and strain identification of PRRSV with a sensitivity of 10(4) and 10(3) copies microl(-1) for SYBR Green and TaqMan probe, respectively.

CONCLUSIONS

Real-time RT-PCR is a powerful method combining rapidity, specificity and efficiency for large-scale screening and strain identification of PRRSV.

SIGNIFICANCE AND IMPACT OF THE STUDY

The data indicate that the methods developed are invaluable for detecting low levels of PRRSV infection in swine.