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Lyme disease (borreliosis) is one of the most common vector-borne diseases worldwide. Its incidence and geographic expansion has been steadily increasing in the last decades. Lyme disease is caused by Borrelia burgdorferi sensu lato, a heterogeneous group of which three genospecies have been systematically associated to Lyme disease: B. burgdorferi sensu stricto Borrelia afzelii and Borrelia garinii. Geographical distribution and clinical manifestations vary according to the species involved. Lyme disease clinical manifestations may be divided into three stages. Early localized stage is characterized by erythema migrans in the tick bite site. Early disseminated stage may present multiple erythema migrans lesions, borrelial lymphocytoma, lyme neuroborreliosis, carditis, or arthritis. The late disseminated stage manifests with acordermatitis chronica atrophicans, lyme arthritis, and neurological symptoms. Diagnosis is challenging due to the varied clinical manifestations it may present and usually involves a two-step serological approach. In the current review, we present a thorough revision of the clinical manifestations Lyme disease may present. Additionally, history, microbiology, diagnosis, post-treatment Lyme disease syndrome, treatment, and prognosis are discussed.

In this investigation, we sought to investigate the characteristics of Citrobacter spp. infections. A retrospective cohort study in a 700-bed, tertiary care, university hospital was carried out during the period from June 1994 to January 2006. Seventy-eight patients (70 adults) with Citrobacter spp. isolates were identified. C. freundii was more common (71.8%), followed by C. koseri (23.1%) and C. braakii (3.8%). The most common associated clinical syndromes were urinary tract infections (52.6% of cases, including eight cases of asymptomatic bacteriuria), as well as intra-abdominal (14.1%), surgical site (7.7%), skin and soft tissue (6.4%), and respiratory tract infections (6.4%). In 29.5% of patients, Citrobacter spp. isolates were associated to polymicrobial infections, principally at sites other than the urinary tract. Antibiograms of 38 consecutive Citrobacter spp. isolates (29 C. freundii) were available. Most active agents were colistin (100%), fosfomycin (100%), imipenem (97.4%), gentamicin (89.5%), nitrofurantoin (89.5%), ciprofloxacin (80.6%), and cefepime (73.7%). Most patients (82.1%) had at least one underlying illness. Combination antimicrobial therapy was administered in 28.2% of cases. One patient died during hospitalization. The length of hospital stay was longer in patients with polymicrobial compared to monomicrobial infections (23 versus 13 days, respectively, p = 0.02). The isolation of Citrobacter species, although rather infrequent, was clinically relevant in the great majority of cases. Further attention should be paid to these pathogens.

Pathogen, host and environmental factors must be considered in order to understand the pathogenesis of dermatophilosis. A frequently cited sequence of events involves physical damage to the skin, bacterial multiplication in the epidermis, repeated cycles of invasion by hyphae, infiltration by neutrophils and exudate, regeneration of epidermis and reinvasion. This paper is concerned with pathogen driven mechanisms involved in the origin and development of Dermatophilus congolensis infections. Primary infections of calves under controlled conditions at clipped, cleaned, defatted sites result in characteristic dermatophilosis crusts, illustrating that D. congolensis itself is pathogenic. Calves infected in this way develop protective immune responses to subsequent infections. In contrast first and second infections of calves simultaneously infested with Amblyomma variegatum result in more severe lesions that take significantly longer to heal than lesions on tick free calves. Immunity to D. congolensis is isolate specific, however the antigens that elicit immunity have not been defined, they might include pathogenic or virulence factors. Hyphae are the life-cycle stage most closely associated with the living epidermis. During in vitro growth hyphae secrete antigens and proteolytic enzymes into culture medium. Proteolytic activity has been linked to virulence of D. congolensis. The characteristics of proteases released into culture medium varies between isolates. This raises the possibility that proteases, with as yet undefined functions, act as pathogenic and virulence factors, that they are the targets for protective immune responses and that A. variegatum infestation interferes with host immune responses that normally inhibit their activity.

In view of the unpredictability of results of antibiotic therapy of bovine dermatophilosis and following the report of successful use of 10% formalin administered intravenously at the dosage of 20 ml per 100 kg body weight, a trial was undertaken to evaluate the latter treatment in naturally-occurring dermatophilosis in a group of Friesian crossbred cattle. Group 1 animals were given only 10% formalin. Group 2 received 10% formalin and long-acting oxytetracycline (L/AO) at a dosage of 20 mg per kg body weight and Group 3 animals were given only L/AO. Treatments were repeated at intervals of four days. All animals recovered fully, the formalin only-treated ones after three treatments the L/AO-treated ones after a mean of 2.7 treatments and the combination-treated animals after a mean of 1.5 treatments. One LA/O-treated animal showed relapse after four months. This study is continuing.