Molecular Epidemiology of Staphylococcus aureus Skin and Soft Tissue Infections in the Lao People's Democratic Republic.

This is the first report of the molecular epidemiology of Staphylococcus aureus from skin and soft tissue infections (SSTI) in Laos. We selected a random sample of 96 S. aureus SSTI isolates received by the Microbiology Laboratory, Mahosot Hospital, Vientiane, between July 2012 and June 2014, including representation from seven referral hospitals. Isolates underwent susceptibility testing by Clinical and Laboratory Standards Institute methods, spa typing and DNA microarray analysis, with whole genome sequencing for rare lineages. Median patient age was 19.5 years (interquartile range 2-48.5 years); 52% (50) were female. Forty-three spa types, representing 17 lineages, were identified. Fifty-eight percent (56) of all isolates encoded Panton-Valentine leukocidin (PVL), representing six lineages: half of these patients had abscesses and three had positive blood cultures. The dominant lineage was CC121 (39; 41%); all but one isolate encoded PVL and 49% (19) were from children under five. Staphyococcus argenteus was identified in six (6%) patients; mostly adults > 50 years and with diabetes. Six isolates (6%) belonged to rare lineage ST2885; two possibly indicate cross-infection in a neonatal unit. One isolate from a previously undescribed lineage, ST1541, was identified. Antibiotic resistance was uncommon except for penicillin (93; 97%) and tetracycline (48; 50%). Seven (7%) isolates were methicillin-resistant S. aureus (MRSA), belonging to ST239-MRSA-III, CC59-MRSA-V(T) Taiwan Clone, ST2250-MRSA-IV, ST2885-MRSA-V and CC398-MRSA-V. Globally widespread CC5 and CC30 were absent. There are parallels in S. aureus molecular epidemiology between Laos and neighboring countries and these data highlight the prominence of PVL and suggest infiltration of MRSA clones of epidemic potential from surrounding countries

Bacteremia Caused by Extended-Spectrum Beta-Lactamase-Producing Enterobacteriaceae in Vientiane, Lao PDR: A 5-Year Study.

Although there has been an increasing incidence of bacteremia caused by extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae (ESBL-E) across South East Asia, there are sparse data from the Lao PDR, where laboratory capacity for antimicrobial resistance surveillance is limited. We, therefore, retrospectively reviewed bacteremia caused by ESBL-producing Escherichia coli and Klebsiella pneumoniae between 2010 and 2014 at Mahosot Hospital, Vientiane, Lao PDR. Clinical and laboratory data relating to all episodes of ESBL-E bacteremia were reviewed over the 5-year period and compared with non-ESBL-E bacteremia. Blood cultures positive for E. coli or K. pneumoniae were identified retrospectively from laboratory records. Clinical and laboratory data were extracted from research databases and case notes and analyzed using STATA. Between 2010 and 2014, we identified 360 patients with E. coli (n = 249) or K. pneumoniae (n = 111) bacteremia, representing 34.8% of all patients with clinically significant bacteremia. Seventy-two (20%) isolates produced ESBL; E. coli accounted for 15.3% (55/360) and K. pneumoniae for 4.7% (17/360), respectively. The incidence of ESBL-producing E. coli bacteremia rose during the study period. By multiple logistic analysis, reported antibiotic use in the previous week was significantly associated with ESBL positivity (P < 0.001, odds ratio 3.89). Although multiresistant, most ESBL-producing E. coli and K. pneumoniae remained susceptible to meropenem (65/65; 100%) and amikacin (64/65; 98.5%). We demonstrated an alarming increase in the incidence of ESBL-E as a cause of bacteremia in Vientiane during the study period. This has implications for empiric therapy of sepsis in Laos, and ongoing surveillance is essential

Antimicrobial Susceptibility Testing of Leptospira spp. in the Lao People's Democratic Republic Using Disk Diffusion.

Leptospirosis is a global zoonotic disease caused by pathogenic bacteria of the Leptospira genus, which are fastidious, slow-growing organisms. Antimicrobial susceptibility data are limited; traditionally, the organisms have not been culturable on solid media. The recent development of Leptospira Vanaporn Wuthiekanun (LVW) agar, which facilitates rapid growth of Leptospira spp., provides the opportunity for antimicrobial susceptibility testing. Eighty-three Leptospira spp. clinical isolates originating from patients in Laos between 2006 and 2016 were tested against six antimicrobials (azithromycin, ceftriaxone, ciprofloxacin, doxycycline, gentamicin, and penicillin G) using disk diffusion on LVW agar. Quality control was undertaken using American Type Culture Collection (ATCC) reference strains with known susceptibilities on both standard media and LVW agar. All Leptospira spp. isolates produced large zones of inhibition around each of the six antimicrobials. All zones were greater than 25 mm: gentamicin produced the smallest zones (median 35 mm; interquartile range 30 mm-37 mm) and azithromycin produced the largest zones (median 85 mm; interquartile range 85 mm-85 mm). Zones produced by non-leptospiral ATCC reference strains on LVW agar were within 2 mm of accepted strain-specific quality control range on standard media. Antimicrobial activity on LVW agar appears to be similar to that on standard media. As there are no published susceptibility guidelines for the Leptospira genus, zone interpretation was subjective. Leptospira Vanaporn Wuthiekanun agar enabled antimicrobial susceptibility testing of multiple Leptospira isolates on solid media; the large zone sizes observed suggest that resistance has not emerged to these six antimicrobials in Lao Leptospira spp

Real-time sampling of travelers shows intestinal colonization by multidrug-resistant bacteria to be a dynamic process with multiple transient acquisitions

AbstractBackgroundAntimicrobial resistance (AMR) is highly prevalent in low- and middle-income countries (LMIC). International travel contributes substantially to the global spread of intestinal multidrug-resistant gram-negative (MDR-GN) bacteria. Of the 100 million annual visitors to LMIC, 30–70% become colonized by MDR-GN bacteria. The phenomenon has been well documented, but since sampling has only been conducted after travelers’ return home, data on the actual colonization process are scarce. We aimed to characterize colonization dynamics by exploring stool samples abroad on a daily basis while visiting LMIC.MethodsA group of 20 European volunteers visiting Lao People’s Democratic Republic for three weeks provided daily stool samples and filled in daily questionnaires. Acquisition of extended-spectrum beta-lactamase-producing gram-negative bacteria (ESBL-GN) was examined by selective stool cultures followed by whole-genome sequencing (WGS) of isolates.ResultsWhile colonization rates were 70% at the end of the study, daily sampling revealed that all participants had acquired ESBL-GN at some time point during their overseas stay, the colonization status varying day by day. WGS analysis ascribed the transient pattern of colonization to sequential acquisition of new strains, resulting in a loss of detectable colonization by the initial MDR-GN strains. All but one participant acquired multiple strains (n=2–7). Of the total of 83 unique strains identified (53 E. coli, 10 Klebsiella, 20 other ESBL-GN species), some were shared by as many as four subjects.ConclusionsThis is the first study to characterize in real time the dynamics of acquiring MDR-GN during travel. Our data show multiple transient colonization events indicative of constant microbial competition.</jats:sec

The effectiveness of the 13-valent pneumococcal conjugate vaccine against hypoxic pneumonia in children in Lao People's Democratic Republic: An observational hospital-based test-negative study

Background: Pneumococcal pneumonia is a leading cause of childhood mortality. Pneumococcal conjugate vaccines (PCVs) have been shown to reduce hypoxic pneumonia in children. However, there are no studies from Asia examining the effectiveness of PCVs on hypoxic pneumonia. We describe a novel approach to determine the effectiveness of the 13-valent PCV (PCV13) against hypoxia in children admitted with pneumonia in the Lao People's Democratic Republic. Methods: A prospective hospital-based, test-negative observational study of children aged up to 59 months admitted with pneumonia to a single tertiary hospital in Vientiane was undertaken over 54 months. Pneumonia was defined using the 2013 WHO definition. Hypoxia was defined as oxygen saturation <90% in room air or requiring oxygen supplementation during hospitalisation. Test-negative cases and controls were children with hypoxic and non-hypoxic pneumonia, respectively. PCV13 status was determined by written record. Vaccine effectiveness was calculated using logistic regression. Propensity score and multiple imputation analyses were used to handle confounding and missing data. Findings: There were 826 children admitted with pneumonia, 285 had hypoxic pneumonia and 377 were PCV13-vaccinated. The unadjusted, propensity-score adjusted and multiple-imputation adjusted estimates of vaccine effectiveness against hypoxic pneumonia were 23% (95% confidence interval: -9, 46%; p=0•14); 37% (6, 57%; p=0•02) and 35% (7, 55%; p=0•02) respectively. Interpretation: PCV13 is effective against hypoxic pneumonia in Asia, and should be prioritised for inclusion in national immunisation programs. This single hospital-based, test-negative approach can be used to assess vaccine effectiveness in other similar settings. Funding: Funded by the Bill & Melinda Gates Foundation

A Prospective Hospital Study to Evaluate the Diagnostic Accuracy of Rapid Diagnostic Tests for the Early Detection of Leptospirosis in Laos.

Leptospirosis is a globally important cause of acute febrile illness, and a common cause of non-malarial fever in Asia, Africa, and Latin America. Simple rapid diagnostic tests (RDTs) are needed to enable health-care workers, particularly in low resource settings, to diagnose leptospirosis early and give timely targeted treatment. This study compared four commercially available RDTs to detect human IgM against Leptospira spp. in a head-to-head prospective evaluation in Mahosot Hospital, Lao PDR. Patients with an acute febrile illness consistent with leptospirosis (N = 695) were included in the study during the 2014 rainy season. Samples were tested with four RDTs: ("Test-it" [Life Assay, Cape Town, South Africa; N = 418]; "Leptorapide" [Linnodee, Ballyclare, Northern Ireland; N = 492]; "Dual Path Platform" [DPP] [Chembio, Medford, NY; N = 530]; and "SD-IgM" [Standard Diagnostics, Yongin, South Korea; N = 481]). Diagnostic performance characteristics were calculated and compared with a composite reference standard combining polymerase chain reaction (PCR) (rrs), microscopic agglutination tests (MATs), and culture. Of all patients investigated, 39/695 (5.6%) were positive by culture, PCR, or MAT. The sensitivity and specificity of the RDTs ranged greatly from 17.9% to 63.6% and 62.1% to 96.8%, respectively. None of the investigated RDTs reached a sensitivity or specificity of > 90% for detecting Leptospira infections on admission. In conclusion, our investigation highlights the challenges associated with Leptospira diagnostics, particularly in populations with multiple exposures. These findings emphasize the need for extensive prospective evaluations in multiple endemic settings to establish the value of rapid tools for diagnosing fevers to allow targeting of antibiotics

Mendelian randomization study of B-type natriuretic peptide and type 2 diabetes: evidence of causal association from population studies

&lt;p&gt;Background: Genetic and epidemiological evidence suggests an inverse association between B-type natriuretic peptide (BNP) levels in blood and risk of type 2 diabetes (T2D), but the prospective association of BNP with T2D is uncertain, and it is unclear whether the association is confounded.&lt;/p&gt; &lt;p&gt;Methods and Findings: We analysed the association between levels of the N-terminal fragment of pro-BNP (NT-pro-BNP) in blood and risk of incident T2D in a prospective case-cohort study and genotyped the variant rs198389 within the BNP locus in three T2D case-control studies. We combined our results with existing data in a meta-analysis of 11 case-control studies. Using a Mendelian randomization approach, we compared the observed association between rs198389 and T2D to that expected from the NT-pro-BNP level to T2D association and the NT-pro-BNP difference per C allele of rs198389. In participants of our case-cohort study who were free of T2D and cardiovascular disease at baseline, we observed a 21% (95% CI 3%-36%) decreased risk of incident T2D per one standard deviation (SD) higher log-transformed NT-pro-BNP levels in analysis adjusted for age, sex, body mass index, systolic blood pressure, smoking, family history of T2D, history of hypertension, and levels of triglycerides, high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol. The association between rs198389 and T2D observed in case-control studies (odds ratio = 0.94 per C allele, 95% CI 0.91-0.97) was similar to that expected (0.96, 0.93-0.98) based on the pooled estimate for the log-NT-pro-BNP level to T2D association derived from a meta-analysis of our study and published data (hazard ratio = 0.82 per SD, 0.74-0.90) and the difference in NT-pro-BNP levels (0.22 SD, 0.15-0.29) per C allele of rs198389. No significant associations were observed between the rs198389 genotype and potential confounders.&lt;/p&gt; &lt;p&gt;Conclusions: Our results provide evidence for a potential causal role of the BNP system in the aetiology of T2D. Further studies are needed to investigate the mechanisms underlying this association and possibilities for preventive interventions.&lt;/p&gt

Clinico-pathological profile of sinonasal masses: an experience in national ear care center Kaduna, Nigeria

<p>Abstract</p> <p>Background</p> <p>The presence of a mass in the nose and paranasal sinuses may seem to be a simple problem; however it raises many questions about the differential diagnosis. The aim of this study is to evaluate the clinico-pathological profile of sinonasal masses in our environment</p> <p>This is a retrospective analytical review of all the patients with sinonasal masses that presented to the national ear care center, Kaduna over a six year (2003-2008) period. Their biodata, clinical profile and histological diagnoses were analyzed.</p> <p>Findings</p> <p>A total of 76 patients were analyzed, age range 5 to 64 yrs with a mean age of 33.3 yr median and modal age of 35.00 (SD = 13.1 ± 1.5). Majority of the patients were in the age groups 21-50 yrs. There were 34 male and 42 female with M: F ratio of 1:1.2. The main presenting symptoms are nasal blockage 97.4% and rhinorrhea 94.7%. It was bilateral in 34 (44.7%), left side in 24(31.6%) and right side in 18(23.7%) patients. The commonest clinical diagnoses were simple nasal polyp 47(61.8%) and antrochoanal polyp 10(13.2%). About 59 (77.6%) were benign, 2 (2.6%) were malignant and 15 (19.7%) were lost to follow up. The commonest histological diagnosis is simple inflammatory nasal polyp in 28 (36.8%) patients and the least was nasal capillary hemangioma 2 (2.6%). About 55(72.4%) patients had surgical treatment.</p> <p>Conclusions</p> <p>Nasal obstruction and rhinorrhea are the commonest symptoms of presentation, simple inflammatory nasal polyp is still the commonest histological pattern seen in our environment, and surgery is still the best modality of treatment for benign tumor thus the need for advocacy for early recognition and referral to the ENT surgeon.</p

Identification of Burkholderia cepacia strains that express a Burkholderia pseudomallei-like capsular polysaccharide

Burkholderia pseudomallei and Burkholderia cepacia are Gram-negative, soil-dwelling bacteria that are found in a wide variety of environmental niches. While B. pseudomallei is the causative agent of melioidosis in humans and animals, members of the B. cepacia complex typically only cause disease in immunocompromised hosts. In this study, we report the identification of B. cepacia strains isolated from either patients or soil in Laos and Thailand that express a B. pseudomallei-like 6-deoxyheptan capsular polysaccharide (CPS). These B. cepacia strains were initially identified based on their positive reactivity in a latex agglutination assay that uses the CPS-specific monoclonal antibody (mAb) 4B11. Mass spectrometry and recA sequencing confirmed the identity of these isolates as B. cepacia (formerly genomovar I). Total carbohydrates extracted from B. cepacia cell pellets reacted with B. pseudomallei CPS-specific mAbs MCA147, 3C5, and 4C4, but did not react with the B. pseudomallei lipopolysaccharide-specific mAb Pp-PS-W. Whole genome sequencing of the B. cepacia isolates revealed the presence of genes demonstrating significant homology to those comprising the B. pseudomallei CPS biosynthetic gene cluster. Collectively, our results provide compelling evidence that B. cepacia strains expressing the same CPS as B. pseudomallei co-exist in the environment alongside B. pseudomallei. Since CPS is a target that is often used for presumptive identification of B. pseudomallei, it is possible that the occurrence of these unique B. cepacia strains may complicate the diagnosis of melioidosis

A novel technique for detecting antibiotic-resistant typhoid from rapid diagnostic tests.

Fluoroquinolone-resistant typhoid is increasing. An antigen-detecting rapid diagnostic test (RDT) can rapidly diagnose typhoid from blood cultures. A simple, inexpensive molecular technique performed with DNA from positive RDTs accurately identified gyrA mutations consistent with phenotypic susceptibility testing results. Field diagnosis combined with centralized molecular resistance testing could improve typhoid management and surveillance in low-resource settings