Characterization of the L-form switch in the Gram-negative pathogen Streptobacillus moniliformis.

Almost all major classes of bacteria are surrounded by a peptidoglycan cell wall, which is a crucial target for antibiotics. It is now understood that many bacteria can tolerate loss of the cell wall provided that they are in an isotonic environment. Furthermore, in some cases the cells can continue to proliferate in a state known as the L-form. L-form proliferation occurs by an unusual blebbing or tubulation mechanism that is completely independent of the normally essential division machine or cell wall synthetic enzymes, and is resistant to cell wall-active antibiotics. However, the growth is limited by reactive oxygen species generated by the respiratory chain pathway. In this work, we examined the walled to L-form transition in a pathogenic Gram-negative bacterium, Streptobacillus moniliformis, which naturally lacks the respiratory chain pathway, under aerobic conditions. L-form-like cells often emerged spontaneously, but proliferation was not observed unless the cells were treated with cell wall-active antibiotics. Time-lapse imaging revealed that cell division of S. moniliformis L-forms involves unusual membrane dynamics with an apparent imbalance between outer membrane and cytoplasmic volume growth. The results suggest that outer membrane expansion may be an important general factor for L-form proliferation of diderm bacteria.

Rat bite fever with osteomyelitis and discitis: case report and literature review.

BACKGROUND: Rat bite fever (RBF) is a rare systemic febrile illness transmitted by rats. Streptobacillus moniliformis is a pleomorphic Gram-negative bacillus which is the usual etiologic organism for rat bite fever in the United States. CASE PRESENTATION: Here we present a case of rat bite fever complicated by vertebral osteomyelitis and discitis. The patient revealed an exposure history of being bitten by pet rats. The patient's symptoms dramatically improved with a six-week course of cephalexin therapy. CONCLUSIONS: It is important to obtain a thorough zoonotic exposure history and maintain rat bite fever in the differential when considering potential causes of discitis and osteomyelitis.

Erosive polyarthritis caused by sepsis due to a novel species of Streptobacillus notomytis.

Rat-bite fever (RBF) is characterized by fever, rash and arthritis, mainly caused by Streptobacillus moniliformis. We present a case of inflammatory erosive polyarthritis with sepsis caused by Streptobacillus notomytis, a novel species isolated from S. moniliformis. A 67-year-old man presented with fever, purpura and peripheral arthritis. After blood cultures were performed, loxoprofen administration was initiated. Arthritis partially improved, but left first metatarsophalangeal (MTP) arthritis persisted. A gram-negative rod was detected in the blood culture, and meropenem administration was started that improved arthritis. Ultrasonography and computed tomography revealed bone erosion in the left first MTP joint, leading to the diagnosis of septic arthritis. 16S rRNA gene sequence analysis revealed that this strain was S. notomytis. Further questioning revealed the patient may have had contact with rats. It is essential to consider Streptobacillus infection in the differential diagnosis of erosive polyarthritis.

Approved and novel strategies in diagnostics of rat bite fever and other Streptobacillus infections in humans and animals.

Rat bite fever (RBF), a worldwide occurring and most likely under-diagnosed zoonosis caused by Streptobacillus moniliformis, represents the most prominent disease of Streptobacillus infections. Recently, novel members have been described, from which a reservoir in rats and other animal species and a zoonotic potential can be assumed. Despite regularly published case reports, diagnostics of RBF continues to represent a 'diagnostic dilemma', because the mostly applied 16S rRNA sequence analysis may be uncertain for proper pathogen identification. Virtually nothing is known regarding prevalence in humans and animal reservoirs. For a realistic assessment of the pathogen's spread, epidemiology and virulence traits, future studies should focus on the genomic background of Streptobacillus. Full genome sequence analyses of a representative collection of strains might facilitate to unequivocally identify and type isolates. Prevalence studies using selective enrichment mechanisms may also enable the isolation of novel strains and candidate species of this neglected group of microorganisms.

A Japanese patient with a rare case of Streptobacillus moniliformis bacteremia.

Streptobacillus moniliformis is the etiological agent of rat-bite fever, a rare disease in Asia that is difficult to diagnose. We describe an elderly patient living in rat-infested conditions who presented with severe sepsis. He was successfully treated with meropenem, and blood culture revealed infection with S. moniliformis.

One-step synthesis of highly-biocompatible spherical gold nanoparticles using Artocarpus heterophyllus Lam. (jackfruit) fruit extract and its effect on pathogens.

INTRODUCTION: Novel approaches for the synthesis of gold nanoparticles (AuNPs) are of great importance due to its vast spectrum of applications in diverse fields, including medical diagnostics and therapeutics. Te presented study reports the successful AuNPs' synthesis using Artocarpus heterophyllus Lam. extract, and provides detailed characterization and evaluation of its antibacterial potential. OBJECTIVE: The aim was to develop a cost-effective and environmentally friendly synthesis method of gold nanoparticles using aqueous fruit extract of Artocarpus heterophyllus Lam. as a reducing and capping agent, which has proven activity against human pathogens, such as microbial species E.coli and Streptobacillus sps. MATERIALS AND METHOD: Characterizations were carried out using ultraviolet-visible (UV-Vis) spectrophotometry, scanning electron microscopy (SEM), energy dispersive X-ray and Fourier-Transform infra-red spectroscopy (FT-IR). RESULTS: SEM images showed the formation of gold nanoparticles with an average size of 20-25 nm. Spectra collected while infra-red analysis contained broad peaks in ranges from 4000-400 cm -1 . CONCLUSIONS: It can be concluded that the fruit of Artocarpus heterophyllus Lam. can be good source for synthesis of gold nanoparticles which showed antimicrobial activity against investigated microbes, in particul E. coli, and Streptobacillus. An important outcome of this study will be the development of value-added products from the medicinal plant Artocarpus heterophyllus Lam. for the biomedical and nanotechnology-based industries.

Rat-bite fever septic arthritis: illustrative case and literature review.

Rat-bite fever is a rare zoonotic infection caused by Streptobacillus moniliformis or Spirillum minus, which is characterised by fever, rash and arthritis. The arthritis has previously been described as non-suppurative and isolation of the organism from synovial fluid as very uncommon. This article reports a case of septic arthritis diagnosed as rat-bite fever when the organism was cultured from synovial fluid and reviews another 15 cases of S. moniliformis septic arthritis reported in the worldwide literature since 1985. Articles were included in this review if S. moniliformis was cultured from synovial fluid. Of the published cases, 88% presented with polyarthritis, affecting small and large joints although two had monoarticular hip sepsis. Fever was present in 88%, rash in 25% and 56% had extra-articular features. Synovial fluid analysis revealed high cell counts in all cases (mean 51,000 x 10(9)/l) with a predominance of polymorphonuclear leucocytes, and organisms were found on Gram stain in only 50%. Penicillin was used for treatment in 56% of cases and surgery was required in 30%. All patients recovered. Rat-bite fever arthritis can be suppurative and attempts should be made to isolate the organism from synovial fluid. The diagnosis should be considered when there is arthritis and a high synovial fluid cell count but no apparent organism, especially when the patient has had contact with rats.

Rat bite fever (Streptobacillus moniliformis) with septicemia in a child.

A 5-year-old girl was admitted to hospital with fever, headache and nausea. Her C-reactive protein raised from less than 11 mg/l to 65 mg/l and she developed a maculopapular, petechial rash, especially pronounced on the soles and palms. After incubation for 3 days, Streptobacillus moniliformis was found in all blood cultures that had been taken. Some weeks before her admission, the girl had been playing with her grandmother's pet rats, which later had died from an unknown disease. There was no history of rat bite. Her condition improved rapidly after treatment with penicillin and chloramphenicol, and she was discharged from hospital after 10 days without sequelae.

Characterisation and antibiotic susceptibilities of Streptobacillus moniliformis.

The characteristics of seven strains of Streptobacillus moniliformis, including four isolates from a recent outbreak of Haverhill fever, are reported. Acid production from carbohydrates was uniform apart from variable reactions with mannose and salicin. Enzymatic reactions determined by the API ZYM system and fatty-acid profiles were generally consistent and may be of value in the rapid identification of S. moniliformis. Penicillin was the most active of the antibiotics tested in vitro, which supports its use as the drug of choice in the treatment of Haverhill fever.

Comparison of media with and without 'Panmede' for the isolation of Streptobacillus moniliformis from blood cultures and observations on the inhibitory effect of sodium polyanethol sulphonate.

Fastidious anaerobe broth and brain-heart infusion cysteine broth supplemented with 'Panmede' (a papain digest of ox liver) 2.5% supported the recovery of five Streptobacillus moniliformis strains from simulated blood cultures. Other media tested in parallel--brain heart infusion cysteine broth without 'Panmede' and Brewer's thioglycollate broth--were unreliable. Sodium polyanethol sulphonate (Liquoid) 0.05%, inhibited five isolates of S. moniliformis, including isolates from patients with Haverhill Fever. Occasionally, Liquoid 0.025% was also inhibitory and a heavy inoculum of one strain, NCTC11194, was completely inhibited by Liquoid 0.012% in simulated nutrient-broth blood cultures. These results suggest that the choice of media included in each blood-culture set is critical for the optimal isolation of S. moniliformis. Brain-heart infusion cysteine broth supplemented with 'Panmede', or commercially available fastidious anaerobe broth, without Liquoid, is recommended.