Influence of Biochemical Features of Burkholderia pseudomallei Strains on Identification Reliability by Vitek 2 System

Musculoskeletal melioidosis-a retrospective review of 22 cases from a tertiary care centre in South Tamilnadu

A retrospective review of culture confirmed musculoskeletal melioidosis reported between December 2014 and February 2024 was conducted. 22 of 100 patients with culture proven melioidosis infection had musculoskeletal involvement. Median age was 47 years with 95.4 % being males. Osteomyelitis, septic arthritis and septic arthritis along with adjacent osteomyelitis were observed in 12, 9 and 4 cases respectively. All isolates were susceptible to meropenem and susceptible increased exposure to ceftazidime, doxycycline and cotrimoxazole. Twelve patients underwent surgical procedures. Four patients who died due to septicemia had multisystem involvement with positive blood cultures.

In vitro susceptibility of Burkholderia pseudomallei isolates from Thai patients to ceftolozane/tazobactam and ceftazidime/avibactam

Treatment options are limited for melioidosis patients who develop nosocomial infection from extensively drug-resistant (XDR) gram-negative bacilli. Ceftolozane/tazobactam (C/T) and ceftazidime/avibactam (CZA), which have activity against XDR gram-negative bacteria, are two potential options. Data regarding the susceptibility of B. pseudomallei to these agents are limited, especially from Thailand, which is an endemic area for melioidosis. A total of 28 B. pseudomallei isolates from melioidosis patients in northeast Thailand were tested for susceptibility to C/T and CZA using the E-test and disk diffusion test. Minimal inhibitory concentrations (MICs) for other antibiotics commonly used in melioidosis, including trimethoprim/sulfamethoxazole (SXT), ceftazidime (CAZ), imipenem (IPM), and meropenem, were also ascertained. The MIC of C/T was very low in all isolates, ranging from 0.75 to 1.0 µg/mL. For CZA, wide inhibitory zones ranging from 34 to 35 mm and MICs at 0.5 µg/mL were found. All isolates were also susceptible to SXT, CAZ, and IPM based on CLSI breakpoints. C/T and CZA exhibited excellent in vitro activity against B. pseudomallei. Further studies are required to prove efficacy in human subjects.

Misidentification of Burkholderia pseudomallei, China

We report a case of melioidosis in China and offer a comparison of 5 commercial detection systems for Burkholderia pseudomallei. The organism was misidentified by the VITEK 2 Compact, Phoenix, VITEK mass spectrometry, and API 20NE systems but was eventually identified by the Bruker Biotyper system and 16S rRNA sequencing.

Case of melioidosis misdiagnosed as pulmonary tuberculosis

Melioidosis is an endemic infection caused by Burkholderia pseudomallei predominantly reported in the coastal parts of India. A 19-year-old male student with no comorbidities presented with features suggestive of pneumonia. He was initiated on antitubercular treatment empirically elsewhere. However, due to lack of response to therapy diagnosis was revisited. Microbiological investigations were unyielding initially. Despite antitubercular treatment, he presented with complications of pneumonia and was diagnosed to have melioidosis. He was initiated on appropriate antibiotics for the intensive and eradication phase. Obtaining microbiological confirmation is of utmost importance to prevent misdiagnosis and undue morbidity and mortality due to these uncommon infections.

Human Melioidosis

The causative agent of melioidosis, Burkholderia pseudomallei, a tier 1 select agent, is endemic in Southeast Asia and northern Australia, with increased incidence associated with high levels of rainfall. Increasing reports of this condition have occurred worldwide, with estimates of up to 165,000 cases and 89,000 deaths per year. The ecological niche of the organism has yet to be clearly defined, although the organism is associated with soil and water. The culture of appropriate clinical material remains the mainstay of laboratory diagnosis. Identification is best done by phenotypic methods, although mass spectrometric methods have been described. Serology has a limited diagnostic role. Direct molecular and antigen detection methods have limited availability and sensitivity. Clinical presentations of melioidosis range from acute bacteremic pneumonia to disseminated visceral abscesses and localized infections. Transmission is by direct inoculation, inhalation, or ingestion. Risk factors for melioidosis include male sex, diabetes mellitus, alcohol abuse, and immunosuppression. The organism is well adapted to intracellular survival, with numerous virulence mechanisms. Immunity likely requires innate and adaptive responses. The principles of management of this condition are drainage and debridement of infected material and appropriate antimicrobial therapy. Global mortality rates vary between 9% and 70%. Research into vaccine development is ongoing.

MELIOIDOSIS AND GLANDERS: CURRENT STATE AND ACTUAL ISSUES OF EPIDEMIOLOGICAL SURVEILLANCE

Burkholderia pseudomallei and Burkholderia mallei are etiologic agents of glanders and melioidosis, the particularly dangerous infections of animals and humans, and are attributed to potential agents of bioterrorism. The manifestation of diseases ranges from acute septicemia to chronic infection, any organs and tissues are affected, andtreatment requires long intravenous and oral antibiotic courses. The endemic zone of glanders and melioidosis covers spacious regions in the world, and the number of imported cases to temperate regions is constantly increasing. For the Russian Federation, glanders and melioidosis are «forgotten» and «unknown» infections, and this review presents current data on their distribution in the world, epidemiological aspects, and laboratory diagnosis features.