Forehead Abscess Caused by Klebsiella oxytoca With Undiagnosed Type 2 Diabetes:

Lytic bacteriophage vB_KmiS-Kmi2C disrupts biofilms formed by members of the Klebsiella oxytoca complex, and represents a novel virus family and genus

AIMS

This study aimed to characterize the lytic phage vB_KmiS-Kmi2C, isolated from sewage water on a GES-positive strain of Klebsiella michiganensis.

METHODS AND RESULTS

Comparative phylogenetic and network-based analyses were used to characterize the genome of phage vB_KmiS-Kmi2C (circular genome of 42 234 bp predicted to encode 55 genes), demonstrating it shared little similarity with other known phages. The phage was lytic on clinical strains of K. oxytoca (n = 2) and K. michiganensis (n = 4), and was found to both prevent biofilm formation and disrupt established biofilms produced by these strains.

CONCLUSIONS

We have identified a phage capable of killing clinically relevant members of the K. oxytoca complex (KoC). The phage represents a novel virus family (proposed name Dilsviridae) and genus (proposed name Dilsvirus).

Klebsiella oxytoca Complex: Update on Taxonomy, Antimicrobial Resistance, and Virulence

Klebsiella oxytoca is actually a complex of nine species-Klebsiella grimontii, Klebsiella huaxiensis, Klebsiella michiganensis, K. oxytoca, Klebsiella pasteurii, Klebsiella spallanzanii, and three unnamed novel species. Phenotypic tests can assign isolates to the complex, but precise species identification requires genome-based analysis. The K. oxytoca complex is a human commensal but also an opportunistic pathogen causing various infections, such as antibiotic-associated hemorrhagic colitis (AAHC), urinary tract infection, and bacteremia, and has caused outbreaks. Production of the cytotoxins tilivalline and tilimycin lead to AAHC, while many virulence factors seen in Klebsiella pneumoniae, such as capsular polysaccharides and fimbriae, have been found in the complex; however, their association with pathogenicity remains unclear. Among the 5,724 K. oxytoca clinical isolates in the SENTRY surveillance system, the rates of nonsusceptibility to carbapenems, ceftriaxone, ciprofloxacin, colistin, and tigecycline were 1.8%, 12.5%, 7.1%, 0.8%, and 0.1%, respectively. Resistance to carbapenems is increasing alarmingly. In addition to the intrinsic bla_OXY, many genes encoding β-lactamases with varying spectra of hydrolysis, including extended-spectrum β-lactamases, such as a few CTX-M variants and several TEM and SHV variants, have been found. bla_KPC-2 is the most common carbapenemase gene found in the complex and is mainly seen on IncN or IncF plasmids. Due to the ability to acquire antimicrobial resistance and the carriage of multiple virulence genes, the K. oxytoca complex has the potential to become a major threat to human health.

Unusual case of a fatal upper esophageal trauma caused by a toothpick

The authors report the case of the unexpected death of a fifty-year-old female found by her partner in the bathroom floor. External examination revealed some contusions dispersed by different corporal areas and an unusually placed green discoloration of the anterior cervical region. After neck dissection and opening the esophagus, a three and a half centimeter wooden toothpick fragment was found at the upper region, covered by a purulent substance associated with puncture wounds. Histopathological and microbiological studies revealed "acute bilateral cervical cellulitis" and Klebsiella Oxytoca, respectively. Further investigation revealed that during the five days prior to her death, the victim was observed twice in an emergency department with complains of throat discomfort after eating some bread with salami. X-Ray and a laryngoscopy were performed but did not reveal any significant findings. Due to the victim's medical history, she was evaluated by a psychiatrist that dismissed a non-somatic setting due to the type of complains and the elevation of blood inflammatory parameters. Rinopharyngitis was then assumed as the most likely diagnosis and was treated accordingly. The victim died the following day. This case reports an unusual fatal traumatic lesion to the upper esophagus that is a very important remainder, particularly for clinical practitioners, to maintain a high degree of suspicion, avoid diagnostic biases such as those related to psychiatric disorders and meticulously evaluate patients in order to deliver the most evidence-based diagnosis possible. To the best of the authors' knowledge there are no other cases described in the literature of a death caused by esophageal toothpick lesion.