Antibiotic susceptibility of clinical Burkholderia pseudomallei isolates in northeast Thailand during 2015-2018 and the genomic characterization of ß-lactam-resistant isolates.

Melioidosis is an often fatal infection in tropical regions caused by an environmental bacterium, Burkholderia pseudomallei Current recommended melioidosis treatment requires intravenous ß-lactam antibiotics such as ceftazidime (CAZ), meropenem (MEM) or amoxicillin-clavulanic acid (AMC) and oral trimethoprim-sulfamethoxazole. Emerging antibiotic resistance could lead to therapy failure and high mortality. We performed a prospective multicentre study in northeast Thailand during 2015-2018 to evaluate antibiotic susceptibility and characterize ß-lactam resistance in clinical B. pseudomallei isolates. Collection of 1,317 B. pseudomallei isolates from patients with primary and relapse infections were evaluated for susceptibility to CAZ, imipenem (IPM), MEM and AMC. ß-lactam resistant isolates were confirmed by broth microdilution method and characterized by whole genome sequence analysis, penA expression and ß-lactamase activity. The resistant phenotype was verified via penA mutagenesis. All primary isolates were IPM-susceptible but we observed two CAZ-resistant and one CAZ-intermediate resistant isolates, two MEM-less susceptible isolates, one AMC-resistant and two AMC-intermediate resistant isolates. One of 13 relapse isolates was resistant to both CAZ and AMC. Two isolates were MEM-less susceptible. Strains DR10212A (primary) and DR50054E (relapse) were multi-drug resistant. Genomic and mutagenesis analyses supplemented with gene expression and ß-lactamase analyses demonstrated that CAZ-resistant phenotype was caused by PenA variants: P167S (N=2) and penA amplification (N=1). Despite the high mortality rate in melioidosis, our study revealed that B. pseudomallei isolates had a low frequency of ß-lactam resistance caused by penA alterations. Clinical data suggest that resistant variants may emerge in patients during antibiotic therapy and be associated with poor response to treatment.

Successful separation of thoracopagus conjoined twins with a single extra-hepatic biliary system.

A pair of thoracopagus conjoined twins were separated at the age of 3 months at Khon Kaen Regional Hospital, Thailand on November 19, 2004. Pre-operative investigations showed separate hearts, joined duodenum, and fusion of the livers. Separation of the extra-hepatic biliary systems was suspected. Operative findings revealed fusion of the intestines from the second part of the duodenum to the terminal ileum with two normal colons. An intussusception was found at the terminal ileum. Fusion of the livers with only one extra-hepatic biliary system was noted In one of the twins, the gastrointestinal tract was anastomosed with Roux-en- Y enteric loop to one area of good bile drainage at the cut surface of liver Post operative course was hectic but both twins recovered satisfactorily. Both are doing well at present, two years after the separation. This was the first reported case of thoracopagus conjoined twins with complex biliary tract anomalies in Thailand. From the literature, pre-operative investigations in most cases of these conjoined twins failed to define the precise anatomy of the biliary system and may be misleading as in the presented case. The mortality rate remains high. Meticulous pre-operative planning, decision-making in the operative field and postoperative management as well as a multidisciplinary team are very important for a successful separation.