Melioidosis in Travelers: Review of the Literature

Melioidosis in a returned traveler: Case report and review of the imported cases in Oman

Melioidosis is an emerging tropical infectious disease in travelers. We present a case of travel related melioidosis in a 65-year-old man with chronic obstructive pulmonary disease and end stage renal disease following a two-week business trip to Thailand and attendance of the Songkran festival. This case emphasizes that vigilance, heightened clinical suspicion, and use of appropriate microbiology diagnostic tools are of paramount importance for a timely diagnosis and successful management. With the ever-increasing global travel, infectious diseases specialists, microbiologists, and public health professionals are constantly challenged by unfamiliar infections in returned travelers.

Melioidosis masquerading as malignancy in tropical Australia; lessons for clinicians and implications for clinical management

Melioidosis is a life-threatening, emerging infectious disease caused by the environmental bacterium Burkholderia pseudomallei. Melioidosis is hyperendemic in tropical Australia and southeast Asia, however the disease is increasingly encountered beyond these regions. Early diagnosis is essential as the infection has a case-fatality rate of up to 50 %. Melioidosis most commonly involves the lungs, although almost any organ can be affected. Most patients present acutely but an insidious presentation over weeks to months is also well described. We present a case series of 7 patients from tropical Australia whom local clinicians initially believed to have cancer ‒ most commonly lung cancer ‒ only for further investigation to establish a diagnosis of melioidosis. All 7 patients had comorbidities that predisposed them to developing melioidosis and all survived, but their delayed diagnosis resulted in 3 receiving anti-cancer therapies that resulted in significant morbidity. The study emphasises the importance of thorough diagnostic evaluation and repeated collection of microbiological samples. It is hoped that our experience will encourage other clinicians ‒ in the appropriate clinical context ‒ to consider melioidosis as a potential explanation for a patient's presentation, expediting its diagnosis and the initiation of potentially life-saving therapy.

Travel-associated melioidosis: a narrative review

BACKGROUND

Melioidosis, caused by Burkholderia pseudomallei, may be considered a neglected tropical disease that remains underdiagnosed in many geographical areas. Travellers can act as the sentinels of disease activity, and data from imported cases may help complete the global map of melioidosis.

METHODS

A literature search for imported melioidosis for the period 2016-22 was performed in PubMed and Google Scholar.

RESULTS

In total, 137 reports of melioidosis associated with travel were identified. The majority were males (71%) and associated with exposure in Asia (77%) (mainly Thailand, 41%, and India, 9%). A minority acquired the infection in the Americas-Caribbean area (6%), Africa (5%) and Oceania (2%). The most frequent comorbidity was diabetes mellitus (25%) followed by underlying pulmonary, liver or renal disease (8, 5 and 3%, respectively). Alcohol/tobacco use were noted for seven and six patients, respectively (5%). Five patients (4%) had associated non-human immunodeficiency virus (HIV)-related immunosuppression, and three patients (2%) had HIV infection. One patient (0.8%) had concomitant coronavirus disease 19. A proportion (27%) had no underlying diseases. The most frequent clinical presentations included pneumonia (35%), sepsis (30%) and skin/soft tissue infections (14%). Most developed symptoms <1 week after return (55%), and 29% developed symptoms >12 weeks after. Ceftazidime and meropenem were the main treatments used during the intensive intravenous phase (52 and 41% of patients, respectively) and the majority (82%) received co-trimoxazole alone/combination, for the eradication phase. Most patients had a favourable outcome/survived (87%). The search also retrieved cases in imported animals or cases secondary to imported commercial products.

CONCLUSIONS

As post-pandemic travel soars, health professionals should be aware of the possibility of imported melioidosis with its diverse presentations. Currently, no licensed vaccine is available, so prevention in travellers should focus on protective measures (avoiding contact with soil/stagnant water in endemic areas). Biological samples from suspected cases require processing in biosafety level 3 facilities.

Melioidosis in a traveller from Africa

A high index of suspicion is necessary to diagnose imported melioidosis in travellers from Africa. Known risk factors include diabetes mellitus, old age and exposure to soil and water. Processing of samples may pose a risk and requires handling in a biosafety level 3 facility.

A case of renal abscess and bacteremia caused by Burkholderia pseudomallei that was first unidentifiable by matrix-assisted laser desorption ionization-time of flight mass spectrometry in a Japanese-man

Melioidosis, an infectious disease caused by Burkholderia pseudomallei, is endemic in specific regions, including Southeast Asia and Northern Australia. In Japan, where no autochthonous has been reported to date, melioidosis is a rare infectious disease. Herein, we report a case of melioidosis in a 68-year-old Japanese man with renal abscess and bacteremia, but without pneumonia. The patient presented to our hospital and was admitted for fever and chills that have persisted for two months. It was speculated that he was infected in Thailand, where his family lives because he shuttled between Thailand and Japan. Blood cultures on admission identified Burkholderia species; however, the species was unidentifiable by matrix-assisted laser desorption ionization-time of flight mass spectrometry. Further re-examination, including culture, loop-mediated isothermal amplification, and multiplex polymerase chain reaction methods, finally identified Burkholderia pseudomallei. We treated the patient with intravenous ceftazidime for four weeks. In addition to the antibiotics administration, puncture drainage of the renal abscess was performed, and he gradually became afebrile. Intravenous ceftazidime was switched to oral sulfamethoxazole/trimethoprim on post-admission day 32, and he was discharged. After five months of oral sulfamethoxazole/trimethoprim, no recurrence was observed one year after discharge. To diagnose melioidosis, especially in non-endemic areas, a precise and thorough understanding of its epidemiology, presentation, and identification methods is necessary.

Primary cutaneous melioidosis acquired in Nepal - Case report and literature review

A 27 years-old Dutch male returning from Nepal presented with a painful abscess on the left forearm without fever or other systemic complications. Signs and symptoms consisted of culture of the abscess material revealed Burkholderia pseudomallei. Laboratory results, chest X-ray and CT scan of the abdomen were without abnormalities. The patient was initially treated with 2 weeks of ceftazidime and continued with a 6-week oral eradication phase with trimethoprim-sulfamethoxazole. The patient recovered without complications. Melioidosis is encountered relatively infrequently as an imported condition, mainly from Southeast Asia with focus on Thailand. Melioidosis from Nepal is a rarity and has previously been described in only four cases, with possible acquisition abroad in three of those.

Cerebral melioidosis in an immunocompromised traveller: an argument for prevention

Melioidosis is a bacterial infection caused by Burkholderia pseudomalleleipseudomallei. This report discusses the case of an immunocompromised traveller who was found to haveacquired cerebral melioidosis during a visit to Thailand, and highlights the need for such travellers to seek specialised travel medicine review prior to travelling to melioidosis endemic regions to discuss preventative strategies.

Melioidosis in Australia

Melioidosis is a potentially fatal bacterial infection caused by the Gram-negative bacillus, Burkholderia pseudomallei following contact with a contaminated environmental source, normally soil or water in tropical and subtropical locations. The disease spectrum varies from rapidly progressive bacteraemic infection with or without pneumonia, to focal lesions in deep soft tissues and internal organs to superficial soft tissue infection and asymptomatic seroconversion with possible long-term dormancy. Most infections occur with a background of chronic illness such as diabetes, chronic kidney disease and alcoholic liver disease. Improvements in diagnosis, targeted antimicrobial treatment and long term follow up have improved clinical outcomes. Environmental controls following rare point source case clusters and heightened awareness of melioidosis appear to have reduced the disease burden in some parts of northern Australia. However, the impact of climate change on dispersal of environmental B. pseudomallei, and changing land use in tropical Australia is expected to change the epidemiology of melioidosis in future.

Investigation of Melioidosis Using Blood Culture and Indirect Hemagglutination Assay Serology among Patients with Fever, Northern Tanzania

Prediction models indicate that melioidosis may be common in parts of East Africa, but there are few empiric data. We evaluated the prevalence of melioidosis among patients presenting with fever to hospitals in Tanzania. Patients with fever were enrolled at two referral hospitals in Moshi, Tanzania, during 2007–2008, 2012–2014, and 2016–2019. Blood was collected from participants for aerobic culture. Bloodstream isolates were identified by conventional biochemical methods. Non–glucose-fermenting Gram-negative bacilli were further tested using a Burkholderia pseudomallei latex agglutination assay. Also, we performed B. pseudomallei indirect hemagglutination assay (IHA) serology on serum samples from participants enrolled from 2012 to 2014 and considered at high epidemiologic risk of melioidosis on the basis of admission within 30 days of rainfall. We defined confirmed melioidosis as isolation of B. pseudomallei from blood culture, probable melioidosis as a ≥ 4-fold rise in antibody titers between acute and convalescent sera, and seropositivity as a single antibody titer ≥ 40. We enrolled 3,716 participants and isolated non-enteric Gram-negative bacilli in five (2.5%) of 200 with bacteremia. As none of these five isolates was B. pseudomallei, there were no confirmed melioidosis cases. Of 323 participants tested by IHA, 142 (44.0%) were male, and the median (range) age was 27 (0–70) years. We identified two (0.6%) cases of probable melioidosis, and 57 (17.7%) were seropositive. The absence of confirmed melioidosis from 9 years of fever surveillance indicates melioidosis was not a major cause of illness.

Melioidosis in travelers: An analysis of Dutch melioidosis registry data 1985-2018

BACKGROUND

Melioidosis, caused by the Gram-negative bacterium Burkholderia pseudomallei, is an opportunistic infection across the tropics. Here, we provide a systematic overview of imported human cases in a non-endemic country over a 25-year period.

METHODS

All 55 Dutch microbiology laboratories were contacted in order to identify all B. pseudomallei positive cultures from 1990 to 2018. A response rate of 100% was achieved. Additionally, a systematic literature search was performed, medical-charts reviewed, and tissue/autopsy specimens were re-assessed.

RESULTS

Thirty-three travelers with melioidosis were identified: 70% male with a median-age of 54 years. Risk factors were present in most patients (n = 23, 70%), most notably diabetes (n = 8, 24%) and cystic fibrosis (n = 3, 9%). Countries of acquisition included Thailand, Brazil, Indonesia, Panama, and The Gambia. Disease manifestations included pneumonia, intra-abdominal abscesses, otitis externa, genitourinary, skin-, CNS-, and thyroid gland infections. Twelve (36%) patients developed sepsis and/or septic shock. Repeat episodes of active infection were observed in five (15%) and mortality in four (12%) patients. Post-mortem analysis showed extensive metastatic (micro)abscesses amongst other sites in the adrenal gland and bone marrow.

CONCLUSIONS

The number of imported melioidosis is likely to increase, given rising numbers of (immunocompromised) travelers, and increased vigilance of the condition. This first systematic retrospective surveillance study in a non-endemic melioidosis country shows that imported cases can serve as sentinels to provide information about disease activity in areas visited and inform pre-travel advice and post-travel clinical management.

A review of melioidosis cases imported into Europe

Melioidosis is a tropical bacterial infection, rarely encountered, and poorly known by clinicians. In non-endemic areas, a misdiagnosis can lead to a fatal outcome. This study aims to identify the main characteristics of imported and diagnosed melioidosis cases in Europe to increase clinician's awareness of this diagnosis. A literature review of imported and diagnosed human melioidosis cases in Europe was performed. PubMed and Web of Science search engines were used for retrieving articles from 2000 to November 2018. Seventy-seven cases of imported melioidosis into Europe described in the literature were identified. More than half of the cases were acquired in Thailand (53%) by men (73%). Patients were usually exposed to Burkholderia pseudomallei during a holiday stay (58%) of less than 1 month (23%) and were hospitalized during the month following their return to Europe (58%). Among travelers, melioidosis is less often associated with risk factor (16%), diabetes being the most frequently comorbidity related (19%). The clinical presentation was multifaceted, pneumonia being the most common symptom (52%), followed by cardiovascular form (45%) and skin and soft tissues damages (35%). The diagnosis was obtained by culture (92%), often supplemented by morphological, biochemical, and molecular identification (23%). Misdiagnoses were common (21%). Over half of the patients received a complete and adapted treatment (56%). Mortality is lower for returning traveler (6%). Imported melioidosis cases into Europe have their own characteristics. This possibility should be considered in patients with pneumonia, fever, and/or abscess returning from endemic areas even years after.

Respiratory Infections

Respiratory tract infections (RTIs) are a common health problem of international travelers. Travelers may be at increased risk of RTIs due to travel itself (mingling and close quarters in airports, airplanes, cruise ships, and hotels), and due to unique exposure at travel destinations. The clinical spectrum of RTIs in travelers is broad and includes upper RTIs, pharyngitis, otitis, laryngitis, bronchitis, and pneumonia. Most travelers who acquire an RTI only develop mild disease, and only a minority seek medical attention. All travelers should be up to date on any indicated vaccines based on age and medical condition that prevent RTIs, including influenza, measles, pneumococcal diseases, Haemophilus influenzae b, Neisseria meningitidis, diphtheria, and pertussis.

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Respiratory tract infections (RTIs) are among the most common illnesses reported by travelers. Most RTIs are viral, involve the upper respiratory tract, and do not require specific diagnosis or treatment.

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Influenza is often considered the most important travel-related infection. Travelers play an integral role in the yearly and global spread of influenza.

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Lower RTIs, including pneumonia, often require antimicrobial therapy.

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High-risk groups such as infants, small children, the elderly, and subjects with chronic tracheobronchial or pulmonary disease are at increased risk of developing severe clinical consequences should infection occur. All international travelers should be immunized for seasonal influenza unless otherwise contraindicated, and travelers should be instructed in hand hygiene and sneeze and cough hygiene.

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All travelers should be up to date on any indicated vaccines that prevent RTIs, including measles, pneumococcal diseases, Haemophilus influenzae b (Hib), meningococcal disease, diphtheria, and pertussis.

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Travelers may be at increased risk of geographically restricted RTIs, and clinicians should be familiar with the major manifestations of these illnesses.

Cutaneous melioidosis: a review of the literature

BACKGROUND

Melioidosis is mainly observed in South-East Asia, where Burkholderia pseudomallei is endemic. Cutaneous melioidosis (CM) has rarely been described and in contrast to systemic forms, there are no therapeutic recommendations to guide management.

METHODS

We reviewed the literature published before January 2018, evaluating: dermatological presentation, natural history, diagnostic methods, and treatment options. We also distinguish between primary and secondary CM in which the infection first started in the skin or came from an extracutaneous localization, respectively, and chronic CM when duration exceeded 2 months. The recommended treatment for systemic forms included ceftazidime or meropenem, followed by oral maintenance therapy with cotrimoxazole or amoxicillin - clavulanic acid.

RESULTS

Forty-three cases were published in 38 articles. Twenty-nine patients (67.4%) were travelers, including 13 (44.8%) returning from Thailand. Thirty-eight patients (88%) had primary CM, including nine (29.9%) with chronic infection. All cases of secondary CM first presented with acute infection. The median incubation time was 3 weeks. The most common presentation was cutaneous abscesses (58%). The recommended treatment was administered in 62.7% cases with 37.2% for maintenance therapy. Sixteen patients (37.2%) underwent surgery. Death was reported in less than 5%.

CONCLUSION

CM should be considered in travelers returning from or residents of endemic countries, particularly Thailand, presenting with cutaneous abscesses, cellulitis, or ulcerations. Surgery may be necessary in a substantial proportion of patients and follow-up of at least 1 year is essential. Therapeutic recommendations need to be established.

Illnesses Associated with Freshwater Recreation During International Travel

PURPOSE OF REVIEW

International travel, adventure travel, and eco-tourism are increasing over the past few decades. This review aims to summarize the spectrum of infections associated with recreational freshwater activities and international travel.

RECENT FINDINGS

Recreational water activities can be associated with a wide range of infections. Acute febrile illnesses due to leptospirosis and schistosomiasis are not uncommon in travelers following extensive freshwater exposure. Aeromonas and other water-associated pathogens are important to consider in a traveler presenting with a skin and soft tissue infection. Recreational water activities are often associated with diarrheal illnesses, especially in children, and the range of enteric pathogens includes bacterial pathogens such as Escherichia coli O157:H7 and Shigella species and the protozoan parasites Cryptosporidium and Giardia duodenalis. Infections due to free-living amebas though rare can lead to fulminant central nervous system infections. A diverse range of infections may be associated with freshwater exposure, and it is important that these entities are considered in a returning traveler presenting with an acute illness.

Epidemiological and Clinical Features of Melioidosis: A Report of Seven Cases from Southern Inland China

Some subtropical regions with similar climatic conditions to melioidosis-endemic areas, such as southern Guangxi, may be new endemic zones for melioidosis. We retrospectively reviewed seven culture-proven melioidosis patients from October 2006 to March 2015. Their clinical characteristics, diagnosis, and treatment, and the geographical and environmental factors were analyzed. Seven male patients lived at latitudes of 21-23°N in Beihai, Nanning, Chongzuo City of the Guangxi Province. Symptom onset occurred during the rainy season. All patients had pneumonia, six patients had diabetes, five patients had a history of wounds or exposure to soil or water, and two patients had liver and spleen abscesses. Most patients were misdiagnosed before the confirmatory laboratory testing. The final diagnosis was confirmed as melioidosis by isolation of Burkholderia pseudomallei in a culture of blood or pus. The 6- to 17-month treatment included carbapenems, ceftazidime, or other antibiotics active against the organism in vitro. All patients initially appeared cured, but two subsequently had recurrent melioidosis. In non-highly endemic areas, there is often a lack of awareness of melioidosis, and this leads to misdiagnoses. Other subtropical regions with climatic conditions similar to the highly melioidosis-endemic areas such as southern Guangxi may also be melioidosis endemic.

Pulmonary Diseases in Refugees and Migrants in Europe

More than 2 million people fleeing conflict, persecution, and poverty applied for asylum between 2015 and 2016 in the European Union. Due to this, medical practitioners in recipient countries may be facing a broader spectrum of conditions and unusual presentations not previously encountered, including a wide range of infections with pulmonary involvement. Tuberculosis is known to be more common in migrants and has been covered broadly in other publications. The scope of this review was to provide an overview of exotic infections with pulmonary involvement that could be encountered in refugees and migrants and to briefly describe their epidemiology, diagnosis, and management. As refugees and migrants travel from numerous countries and continents, it is important to be aware of the various organisms that might cause disease according to the country of origin. Some of these diseases are very rare and geographically restricted to certain regions, while others have a more cosmopolitan distribution. Also, the spectrum of severity of these infections can vary from very benign to severe and even life-threatening. We will also describe infectious and noninfectious complications that can be associated with HIV infection as some migrants might originate from high HIV prevalence countries in sub-Saharan Africa. As the diagnosis and treatment of these diseases can be challenging in certain situations, patients with suspected infection might require referral to specialized centers with experience in their management. Additionally, a brief description of noncommunicable pulmonary diseases will be provided.

Emerging Infections and Pertinent Infections Related to Travel for Patients with Primary Immunodeficiencies

In today's global economy and affordable vacation travel, it is increasingly important that visitors to another country and their physician be familiar with emerging infections, infections unique to a specific geographic region, and risks related to the process of travel. This is never more important than for patients with primary immunodeficiency disorders (PIDD). A recent review addressing common causes of fever in travelers provides important information for the general population Thwaites and Day (N Engl J Med 376:548-560, 2017). This review covers critical infectious and management concerns specifically related to travel for patients with PIDD. This review will discuss the context of the changing landscape of infections, highlight specific infections of concern, and profile distinct infection phenotypes in patients who are immune compromised. The organization of this review will address the environment driving emerging infections and several concerns unique to patients with PIDD. The first section addresses general considerations, the second section profiles specific infections organized according to mechanism of transmission, and the third section focuses on unique phenotypes and unique susceptibilities in patients with PIDDs. This review does not address most parasitic diseases. Reference tables provide easily accessible information on a broader range of infections than is described in the text.

Pneumonia in the tropics

Pneumonia in the tropics poses a heavy disease burden. The complex interplay of climate change, human migration influences and socio-economic factors lead to changing patterns of respiratory infections in tropical climate but also increasingly in temperate countries. Tropical and poorer countries, especially South East Asia, also bear the brunt of the global tuberculosis (TB) pandemic, accounting for almost one-third of the burden. But, as human migration patterns evolve, we expect to see more TB cases in higher income as well as temperate countries, and rise in infections like scrub typhus from ecotourism activities. Fuelled by the ease of air travel, novel zoonotic infections originating from the tropics have led to global respiratory pandemics. As such, clinicians worldwide should be aware of these new conditions as well as classical tropical bacterial pneumonias such as melioidosis. Rarer entities such as co-infections of leptospirosis and chikungunya or dengue will need careful consideration as well. In this review, we highlight aetiologies of pneumonia seen more commonly in the tropics compared with temperate regions, their disease burden, variable clinical presentations as well as impact on healthcare delivery.

Rapid Filter-Based Detection and Culture of Burkholderia pseudomallei from Small Volumes of Urine

Clinical outcomes of melioidosis patients improve when the infecting agent, Burkholderia pseudomallei, is rapidly detected and identified by laboratory testing. Detection of B. pseudomallei DNA or recovery of the pathogen by culture from urine can support a diagnosis of melioidosis and guide patient care. Two new methods, designated filter-capture DNA isolation (FCDI) and filter cellular recovery (FCR), were developed to increase the sensitivity of detection and recovery of viable B. pseudomallei cells from small volumes (0.45 ml) of urine. DNA from eight strains of B. pseudomallei that were spiked into synthetic urine at low concentrations (1 × 10² CFU/ml) was detected in FCDI cell lysates using real-time PCR with greater consistency than with preparations from a QIAamp DNA Blood minikit. The FCR method showed greater B. pseudomallei detection sensitivity than conventional urine culture methods and resulted in typical colony growth at 24 h from as few as 1 × 10² CFU/ml. In addition, the FCR method does not rely on precipitation of a urine pellet by centrifugation and requires a smaller volume of urine. The FCDI and FCR methods described here could improve time-to-results and decrease the number of negative B. pseudomallei reports that are currently observed from urine culture as a consequence of samples containing low or variable bacterial cell concentrations.

Importance of a Travel History in Evaluation of Respiratory Infections

PURPOSE OF REVIEW

International travel has increased at a fast pace and will continue to rapidly rise. Concomitantly, with this increase in travel is the increase in post travel-related diseases, such as respiratory illnesses. Identifying the cause of the posttravel respiratory illness is a complex challenge for many healthcare professionals because similar presentations occur for both infectious and noninfectious causes. Not only is diagnosis important but also transmission prevention. In the last two decades, there have been several severe infectious respiratory syndromes that have spread through international travel causing epidemics in many countries.

RECENT FINDINGS

A detailed travel history with the chronology of symptoms paired with the patient's medical risk factors and exposures along with some basic knowledge of infectious respiratory illnesses will help facilitate clinical decision making. This framework will help create a broad, but appropriate differential diagnosis to guide clinical workup, prevent delays in diagnosis, and implement the appropriate precautions to prevent transmission if appropriate.

SUMMARY

The foundation to diagnosing a travel-related respiratory illness lies within integrating the patient's travel history, comorbid conditions, clinical presentation, exposures, and mode of transmission. A timely and accurate diagnosis benefits not only the patient but also the surrounding community to prevent further individual transmission, epidemics, and pandemics.