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Mycoplasma ovis is a small, pleiotropic bacterium, which parasitizes the external surface of erythrocytes of several species of artiodactyl mammals, especially sheep and goats. We here report an outbreak of ovine mycoplasmosis in a sheep flock of a private ranch (Universidad Veracruzana) in Veracruz, Mexico. For the identification of Mycoplasma and other hemoparasitic bacterial agents, we stained blood smears with the DiffQuick® technique and additionally amplified several fragments of 16S rDNA gene. We detected the presence of morulas in erythrocytes from 30 sick female adult sheep, and found Mycoplasma ovis DNA in all of them. Furthermore, three of these animals also tested positive for Anaplasma ovis. Our findings represent the first record of M. ovis and A. ovis in an outbreak of hemolytic anemia in a sheep flock, leading to severe livestock loss in a ranch of Mexico. This study highlights the importance of establishing an active surveillance of both pathogens in the country.

One Holstein cow housed with 21 other cows exhibited clinical signs of pyrexia, anorexia and diarrhea along with severe hemoglobinuria. Hematological and biochemical analyses conducted before and after antibiotic therapy indicated severe hemolytic anemia and disruption of hepatic function. A general improvement in conditions was observed after an 11-day program of treatment comprising a regular dose of antibiotics and prescribed supportive therapies. A tentative diagnosis of bacillary hemoglobinuria was made based on the clinical and clinico-pathologic features on day 7. A molecular diagnosis was made by a PCR amplification of the flagellin gene of Clostridium haemolyticum using DNA extracted from the whole blood. The cow was diagnosed with the first recorded occurrence of bacillary hemoglobinuria of Holstein cattle in Japan.

Background: Clostridium perfringens (C. perfringens) can cause various infections, including gas gangrene, crepitant cellulitis, and fasciitis. While C. perfringens sepsis is uncommon, it is often rapidly fatal because the alpha toxin of this bacterium induces massive intravascular hemolysis by disrupting red blood cell membranes., Case Report: We present the case of a male patient with diabetes who developed a fatal liver abscess with massive intravascular hemolysis and septic shock caused by toxigenic C. perfringens. The peripheral blood smear showed loss of central pallor, with numerous spherocytes. Multiplex PCR only detected expression of the cpa gene, indicating that the pathogen was C. perfringens type A., Conclusions: C. perfringens infection should be considered in a febrile patient who has severe hemolytic anemia with a very low MCV, hemolyzed blood sample, and negative Coombs test. The characteristic peripheral blood smear findings may facilitate rapid diagnosis.

Background: Pneumococcal hemolytic uremic syndrome (P-HUS) is a rare but severe complication of invasive pneumococcal disease (IPD) in young children. Consensual biologic diagnosis criteria are currently lacking., Study Design and Methods: A prospective study was conducted on 10 children with culture-confirmed IPD. Five presented with full-blown P-HUS, three had an incomplete form with hemolytic anemia and mild or no uremia (P-HA), and two had neither HUS nor HA. Thomsen-Friedenreich (T), Th, and Tk cryptantigens and sialic acid expression were determined on red blood cells (RBCs) with peanut (PNA), Glycine soja (SBA), Bandeiraea simplicifolia II, and Maackia amurensis lectins. Plasma concentrations of the major endogenous T-antigen-binding protein, galectin-3 (Gal-3), were analyzed., Results: We found that RBCs strongly reacted with PNA and SBA lectins in all P-HUS and P-HA patients. Three P-HUS and three P-HA patients showed also concomitant Tk activation. Direct antiglobulin test (DAT) was positive in three P-HUS (one with anti-C3d and two with anti-IgG) and two P-HA patients (one with anti-C3d and one with anti-IgG). RBCs derived from the two uncomplicated IPD patients reacted with PNA but not with SBA lectin. Gal-3 plasma concentrations were increased in all P-HUS patients., Conclusions: The results indicate high levels of neuraminidase activity and desialylation in both P-HUS and P-HA patients. T-antigen activation is more sensitive than DAT for P-HUS diagnosis. Combining PNA and SBA lectins is needed to improve the specificity of T-antigen activation. High concentrations of Gal-3 in P-HUS patients suggest that Gal-3 may contribute to the pathogenesis of P-HUS., (© 2014 AABB.)

We sought to understand the situation of macrolide-resistant genotypes of Mycoplasma pneumoniae, and analyze the relationship between macrolide-resistant genotypes and clinical manifestations of Mycoplasma pneumoniae pneumonia (MPP). Full-length sequencing of the 23S rRNA gene of M. pneumoniae was performed in 235 nasopharyngeal aspirates (NPAs) from children with MPP. We also retrospectively compared the clinical characteristics of macrolide-resistant (MR) M. pneumoniae infections and macrolide-sensitive (MS) M. pneumoniae infections. A total of 206 patients had point mutations in the M. pneumoniae 23S rRNA gene, and these patients are referred to as MR patients. The remaining 29 patients without point mutations are referred to as MS patients. Among 206 MR patients, 199 (96.6%) had A2063G mutations, 6 had A2063T mutations, and the remaining patients had an A2064G mutation. Among the clinical manifestations, we found that the median fever durations were 8 days (range, 0 to 42 days) and 6 days (0 to 14 days) (P < 0.01), the median hospitalization durations were 8 days (2 to 45 days) and 6 days (3 to 16 days) (P < 0.01), and the median fever durations after macrolide therapy were 5 days (0 to 42 days) and 3 days (0 to 10 days) (P < 0.01), respectively, in the MR and MS groups. We also found that the incidence of extrapulmonary complications in the MR group was significantly higher than that in the MS group (P < 0.05). Moreover, the radiological findings were more serious in the MR group than in the MS group (P < 0.05). The increasing prevalence of MR M. pneumoniae has become a significant clinical issue in the pediatric patients, which may lead to more extrapulmonary complications and severe clinical features and radiological manifestations.

Sago haemolytic disease is a rare but sometimes fatal disease found primarily in the coastal regions of Papua New Guinea and among groups in which sago is a primary source of carbohydrate. It has been known since 1961 and fungi consistently have been suspected of being involved. Investigations carried out on stored sago and samples recovered from poisoning episodes have failed to indicate the consistent presence of mycotoxins. However, fungi (especially Aspergillus, Fusarium, Penicillium, Trichoderma) with strong haemolytic activity have been associated with sago, particularly when stored in open-weave baskets and sago-leaf-wrapped bundles. The haemolytic activity has been attributed to fatty acids (principally oleic, palmitic, linoleic) contained primarily in the fungal hyphae. It is hypothesized that when these acids are released through hyphal breakdown during digestion and are present in individuals with a low serum albumin level, free fatty acid excess occurs resulting in red cell membrane destruction and intravascular haemolysis. In extreme cases, blood transfusion is required. Methods of storage providing high levels of access to oxygen favour the development of fungi: eg, leaf-encased bundles and open-weave storage favour growth over that seen in starch stored under water, such as in earthen vessels. Ensuring storage does not exceed 3-4 weeks, encouraging anaerobic conditions of the starch and maintaining protein nutrition in communities where sago is relied upon should alleviate outbreak episodes.

A 9-year-old Thoroughbred gelding was presented for swelling over the left neck and inappetence. There was recent history of intramuscular administration of flunixin meglumine into the left neck. On examination, there was evidence of focal myositis, anaemia, haemolysis and pigmenturia. Culture of aspirated fluid from the left side of the neck produced a heavy growth of a Clostridium species. Complications of infection included haemolytic anaemia, hepatopathy, osteitis and transient hypertrophic cardiomyopathy. Treatment included intravenous fluid therapy, antibiotics, anti-inflammatory drugs, blood transfusion and surgical debridement. There was complete resolution of clinical, haematological, biochemical and echocardiographic abnormalities, and the horse returned to ridden work. This report highlights the complications that can arise from clostridial myonecrosis, including the effect on the myocardium., (© 2013 The Authors. Australian Veterinary Journal © 2013 Australian Veterinary Association.)

Salmonella, a ubiquitous Gram-negative intracellular bacterium, is a food borne pathogen that infects a broad range of hosts. Infection with Salmonella Typhimurium in mice is a broadly recognized experimental model resembling typhoid fever in humans. Using a N-ethyl-N-nitrosurea (ENU) mutagenesis recessive screen, we report the identification of Ity16 (Immunity to Typhimurium locus 16), a locus responsible for increased susceptibility to infection. The position of Ity16 was refined on chromosome 8 and a nonsense mutation was identified in the ankyrin 1 (Ank1) gene. ANK1 plays an important role in the formation and stabilization of the red cell cytoskeleton. The Ank1(Ity16/Ity16) mutation causes severe hemolytic anemia in uninfected mice resulting in splenomegaly, hyperbilirubinemia, jaundice, extramedullary erythropoiesis and iron overload in liver and kidneys. Ank1(Ity16/Ity16) mutant mice demonstrated low levels of hepcidin (Hamp) expression and significant increases in the expression of the growth differentiation factor 15 (Gdf15), erythropoietin (Epo) and heme oxygenase 1 (Hmox1) exacerbating extramedullary erythropoiesis, tissue iron deposition and splenomegaly. As the infection progresses in Ank1(Ity16/Ity16), the anemia worsens and bacterial load were high in liver and kidneys compared to wild type mice. Heterozygous Ank1(+/Ity16) mice were also more susceptible to Salmonella infection although to a lesser extent than Ank1(Ity16/Ity16) and they did not inherently present anemia and splenomegaly. During infection, iron accumulated in the kidneys of Ank1(+/Ity16) mice where bacterial loads were high compared to littermate controls. The critical role of HAMP in the host response to Salmonella infection was validated by showing increased susceptibility to infection in Hamp-deficient mice and significant survival benefits in Ank1(+/Ity16) heterozygous mice treated with HAMP peptide. This study illustrates that the regulation of Hamp and iron balance are crucial in the host response to Salmonella infection in Ank1 mutants.

Background: Clostridium perfringens bacteremia accompanied by extensive intravascular hemolysis is an almost inescapably fatal infection., Methods: Case report and literature review., Results: A 52-year-old man with a recent history of liver transplantation developed sepsis and severe hemolytic anemia. The patient had multiple organ dysfunction syndrome and required aggressive transfusion, antibiotics, and continuous hemodialysis. Blood cultures grew C. perfringens. With appropriate resuscitation and antibiotic treatment, the patient had a complete, although complicated recovery., Conclusion: This is the first reported case of a liver transplant patient developing fulminant C. perfringens sepsis with hemolysis. This infection usually kills patients within hours of presentation. Early recognition and aggressive treatment is necessary to avoid this outcome.

Sustained erythropoiesis and concurrent bone marrow hyperplasia are proposed to be responsible for low bone mass density (BMD) in chronic hemolytic pathologies. As impaired erythropoiesis is also frequent in these conditions, we hypothesized that free heme may alter marrow and bone physiology in these disorders. Bone status and bone marrow erythropoiesis were studied in mice with hemolytic anemia (HA) induced by phenylhydrazine (PHZ) or Plasmodium infection and in bled mice. All treatments resulted in lower hemoglobin concentrations, enhanced erythropoiesis in the spleen and reticulocytosis. The anemia was severe in mice with acute hemolysis, which also had elevated levels of free heme and ROS. No major changes in cellularity and erythroid cell numbers occurred in the bone marrow of bled mice, which generated higher numbers of erythroid blast forming units (BFU-E) in response to erythropoietin. In contrast, low numbers of bone marrow erythroid precursors and BFU-E and low concentrations of bone remodelling markers were measured in mice with HA, which also had blunted osteoclastogenesis, in opposition to its enhancement in bled mice. The alterations in bone metabolism were accompanied by reduced trabecular bone volume, enhanced trabecular spacing and lower trabecular numbers in mice with HA. Taken together our data suggests that hemolysis exerts distinct effects to bleeding in the marrow and bone and may contribute to osteoporosis through a mechanism independent of the erythropoietic stress.

We examined the presence of hemoplasmas, hemotropic mycoplasmas, among 11 sheep (Ovis aries) with regenerative and hemolytic anemia and found six of them were positive by real-time PCR. The positive samples were then subjected to conventional PCR for direct sequencing of the 16S rRNA gene. Nucleotide sequences of all the positive samples were identified as the 16S rRNA gene of `Candidatus Mycoplasma haemovis' by phylogenetic analysis, demonstrating the infections with this particular hemoplasma species in Japan.

Here, we present the genome sequence of Mycoplasma haemofelis strain Langford 1, representing the first hemotropic mycoplasma (hemoplasma) species to be completely sequenced and annotated. Originally isolated from a cat with hemolytic anemia, this strain induces severe hemolytic anemia when inoculated into specific-pathogen-free-derived cats. The genome sequence has provided insights into the biology of this uncultivatable hemoplasma and has identified potential molecular mechanisms underlying its pathogenicity.

Mycoplasma suis (formerly known as Eperythrozoon suis ) is the most prevalent agent causing haemolytic anaemia in swine. The disease is also known as porcine eperythrozoonosis. M.suis is a small, pleomorphic bacteria parasitizing porcine erythrocytes. To date, no in vitro cultivation system for M.suis has been established and, therefore, our knowledge about the characteristics of M.suis and the pathogenesis of porcine eperythrozoonosis is rather limited. M.suis can cause acute disease, but the major significance of M.suis infections lies in the fact that M.suis can establish chronic and persistent infections leading to a higher susceptibility to other infections, especially of the respiratory and digestive tracts. The present article summarizes the current knowledge of the pathogen, the clinical signs and pathogenesis, diagnostic as well as therapy and prophylaxis.

Hemotrophic mycoplasmas (HM) are uncultivable bacteria found on and in the red blood cells (RBCs). The main clinical sign of HM infections is the hemolytic anemia. However, anemia-inducing pathogenesis has not been totally clarified. In this work we used the splenectomized pig as animal model and Mycoplasma suis as a representative for hemotrophic mycoplasmas to study anemia pathogenesis. Eryptosis, i.e. programmed cell death of RBCs, is characterized by cell shrinkage, microvesiculation and phosphatidylserine (PS) exposure on the outer membrane. The eryptosis occurrence and its influence on anemia pathogenesis was observed over the time-course of M. suis infections in pigs using 3 M. suis isolates of differing virulence. All 3 isolates induced eryptosis, but with different characteristics. The occurrence of eryptosis could as well be confirmed in vitro: serum and plasma of an acutely ill pig induced PS exposure on erythrocytes drawn from healthy pigs. Since M. suis is able to induce eryptotic processes it is concluded that eryptosis is one anemia-inducing factor during M. suis infections and, therefore, plays a significant role in the pathogenesis of infectious anemia due to HM infection., (Copyright © 2011 S. Karger AG, Basel.)

Sago hemolytic disease (SHD) is an acute hemolytic syndrome affecting rural Papua New Guineans who depend on the starch of Metroxylon sagu as a staple carbohydrate. It is a suspected mycotoxicosis associated with fungal succession in stored and perhaps poorly fermented sago. Despite a mortality rate of approximately 25%, little is know about the disease. Recent studies have identified Penicillium citrinum as a possible candidate in the etiology of SHD. This is based on the frequency of isolation from sago starch and the hemolytic nature of the organism as demonstrated when cultured on sheep and human blood agar. A highly non-polar lipophilic P. citrinum fraction from C18 solid phase extraction demonstrated high hemolytic activity in a semi-quantitative assay using both mouse and human erythrocytes. When the red cell membrane proteins were subjected to sodium dodecyl-sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) separation, cleavage of protein band 3 and spectrin was demonstrated. This breach of major structural red cell proteins is consistent with the severe hemolysis found in vivo. Our findings warrant further investigation into the hemolytic activity of P. citrinum and its role as the etiological agent of SHD.

This study summarizes the diagnostic findings from all anemic cats diagnosed with hemotropic mycoplasma (HM) infections at the Western College of Veterinary Medicine-Veterinary Teaching Hospital between 1996 and 2005. The objectives were to determine the frequency of HM-induced anemia among all cats presented with anemia during this period, the clinical findings and risk factors associated with clinical HM infection, and factors affecting or predicting survival. Medical records were examined from 23 cats with HM-induced anemia from the total of 170 cats diagnosed with anemia during this period. The frequency of HM-induced anemia was 14% (23/170) among all anemic cats. Cats with HM-induced anemia were less likely to be purebred (P = 0.04) than other cats with anemia. Of the cats with HM-induced anemia, those with positive retroviral status (P = 0.01), concurrent illness (P < 0.01), or lack of erythroid regeneration (P = 0.01) were most likely to die. The 1-year survival of HM-infected cats was 65% (13/20).

After the first outbreak of fatal Mycoplasma ovis infection (eperythrozoonosis) in a sheep flock in Hungary (1997), a second wave of the disease was noted in 2006, with different seasonal pattern and affected age group, as well as increased mortality (5.5%). The aim of the present study was to molecularly characterize the causative agent and to reveal underlying factors of the second wave of the disease. Remarkably, among the 33 sheep examined, 17 were infected with two strains of haemotropic mycoplasmas. Cloning and sequencing isolates of the latter showed that one of the strains was 99.4-99.8% identical to M. ovis (AF338268), while the second was only 96.8-97.9% identical and contained a 17-bp deletion. Different isolates of both strains were demonstrated in the same animal. When analyzing possible risk factors for fatal disease outcome, we found that among sheep born prior to the 1997 outbreak significantly more animals survived the second outbreak than succumbed to disease. In addition, locally born sheep were less frequently diseased than sheep introduced into the flock from other places. This suggests an immunoprotective effect in some animals. Concurrent infection with Anaplasma ovis was detected in 24 of the 33 evaluated sheep. In conclusion, this is the first study to demonstrate the existence of and characterize two genetically distinct ovine haemotropic mycoplasma strains in a sheep flock with fatal haemolytic anaemia.

Although haemobartonellosis was previously reported in Hungary, until now the diagnosis (based on morphological identification in blood smears) has only been suggestive of the occurrence of the large species, recently reclassified as Mycoplasma haemofelis. However, in July 2007 a cat was presented at a small animal clinic with severe haemolytic anaemia, icterus and haemoglobinuria. While biochemical parameters were within the reference range, the cat had leukocytosis and rapidly decreasing haematocrit values, and eventually died 7 days after the sudden onset of aggravating clinical signs. From blood samples of the cat 'Candidatus Mycoplasma haemominutum' was identified by molecular methods, according to its 100% 16S rRNA gene sequence homology with two Swiss isolates and one isolate from the UK. The rapid termination of the disease and the high pathogenicity of the causative agent observed in this case are unusual, taking into account that PCR results were negative for immunosuppressive viruses. This is the first record of this feline haemoplasma species in Hungary.

The incidence of glucose-6-phosphate dehydrogenase deficiency in neonates of immigrant mothers in Canada is increasing. Newborn screening programs in Canada do not screen for this disorder. Infants with G-6-PD deficiency may develop jaundice resulting in kernicterus with devastating sequelae. In this case report, we speculate that Clostridium difficile infection may have triggered severe jaundice in G-6-PD-deficient neonates.

During a 3-mo period, 9 of the 15 New Zealand White rabbits used in a heart failure study developed a hemolytic anemia. The heart failure model involved the creation of an aortic insufficiency (AI) followed 2 to 6 wk later by the creation of an aortic stenosis (AS). None of the 9 animals that developed hemolytic anemia responded to medical management, and 6 of the 9 were euthanized for humane concerns. Necropsies and blood cultures were performed on all anemic animals; 7 of these cultures yielded growth of Achromobacter xylosoxidans. In addition, cultures from the heart valves of 2 rabbits yielded growth of Achromobacter xylosoxidans. We presume that the endocarditis caused by Achromobacter xylosoxidans led to the mechanical damage of red blood cells (RBCs) and subsequent intravascular hemolysis or splenic destruction of damaged RBCs, resulting in a severe, regenerative hemolytic anemia. Achromobacter xylosoxidans is an aerobic, catalase-positive, oxidase-positive, gram-negative bacillus. This organism is an environmentally resistant and opportunistic bacterium that typically inhabits aqueous environments. Microbial samples from the investigator's laboratory and equipment were collected to identify the source of the bacteria. A pressure transducer and bag of intravenous fluid were identified as sources of contamination.

Background: Among the most severe complications of invasive pneumococcal infection are hemolytic uremic syndrome (P-HUS) and hemolytic anemia (P-HA), which occur when the Thomsen-Freidenreich antigen (TA) is exposed on erythrocytes, platelets and glomeruli., Methods: To determine the positive predictive value, sensitivity, and specificity of early TA activation testing for P-HUS or P-HA and to compare the microbiologic features of pneumococcus isolates associated or not associated with TA activation. The case records for 36 patients with invasive pneumococcal infection who had been tested for TA activation were retrospectively reviewed. Clinical and laboratory data were compared between patients with and without TA activation., Results: Positive TA activation was 86% sensitive and 57% specific for P-HUS or P-HA. The positive predictive value was 76%. There were no between-group differences in antibiotic susceptibility of the pneumococcal isolates. Pneumococcal serotype 14 was the most frequent (5/10 isolates tested) serotype causing P-HUS. Of the 36 patients, 13 required packed red blood cell transfusion, 3 died, and 2 required extracorporeal membrane oxygenation. No patient had long-term renal sequelae., Conclusions: TA activation is a reasonable predictor of P-HUS or P-HA and could be useful if tested soon after invasive pneumococcal disease is first diagnosed.

Two feline hemotropic mycoplasma spp. (aka hemoplasma) have previously been recognized. We recently discovered a third novel species in a cat with hemolytic anemia, designated 'Candidatus Mycoplasma turicensis', which is closely related to rodent haemoplasmas. This novel species induced anemia after experimental transmission to two SPF cats. Three quantitative real-time PCR assays were newly designed and applied to an epidemiological study surveying the Swiss pet cat population. Blood samples from 713 healthy and ill cats were analyzed. Up to 104 parameters per cat (detailed questionnaire, case history, laboratory parameters and retroviral infections) were evaluated. 'Candidatus Mycoplasma haemominutum' infection was more prevalent (8.5%) than Mycoplasma haemofelis (0.5%) and 'Candidatus Mycoplasma turicensis' (1%). Hemoplasma infections were associated with male gender, outdoor access, and old age, but not with disease or anemia. Infections were more frequently found in the South and West of Switzerland. Several hemoplasma infected cats, some acutely infected, others co-infected with FIV or FeLV, showed hemolytic anemia indicating that additional factors might play a role in the pathogenesis of the disease.

Recently, there has been a growing interest in hemotropic mycoplasmal species (also known as the hemoplasmas), the causative agents of infectious anemia in several mammalian species. In felids, two different hemoplasma species have been recognized: Mycoplasma haemofelis (formerly Haemobartonella felis) and "Candidatus Mycoplasma haemominutum." Recently developed molecular methods have allowed sensitive and specific identification and quantification of these agents in feline blood samples. In applying these methods to an epidemiological study surveying the Swiss pet cat population for hemoplasma infection, we discovered a third novel and unique feline hemoplasma isolate in a blood sample collected from a cat that had exhibited clinical signs of severe hemolytic anemia. This agent was readily transmitted via intravenous inoculation to two specific-pathogen-free cats. One of these cats was immunocompromised by the administration of methylprednisolone acetate prior to inoculation, and this cat developed severe anemia. The other immunocompetent cat showed a moderate decrease in packed cell volume. Additionally, an increase in red blood cell osmotic fragility was observed. Sequencing of the entire 16S rRNA gene of the new hemoplasma isolate and phylogenetic analysis showed that the isolate was most closely related to two rodent hemotropic mycoplasmal species, M. coccoides and M. haemomuris. A quantitative real-time PCR assay specific for this newly discovered agent was developed, which will be a prerequisite for the diagnosis of infections with the new hemoplasma isolate.

A 3-year-old sexually intact male Bull Mastiff underwent splenectomy for splenic thrombosis; prior to and after splenectomy, multiple blood transfusions were administered. Two weeks after the procedure, T-cell lymphoproliferative disease was diagnosed. Treatment with prednisone and chlorambucil was initiated, and 2 weeks later, cytologic examination of a blood smear revealed small (0.3 microm), coccoid basophilic bodies on the surface of approximately 70% of the RBCs. Morphologically, these resembled "Candidatus Mycoplasma haemominutum." A polymerase chain reaction assay was used to amplify a partial 16S rRNA sequence in blood obtained from the dog; the product was sequenced and compared with 16S rRNA gene sequences of other hemotropic mycoplasmas. The sequence was 98% homologous to that of "Candidatus M haemominutum", but only 77% homologous to that of M haemocanis and M haemofelis.

Eperythrozoon ovis, an erythrocytic agent that causes haemolytic anaemia in sheep and goats, occurs worldwide and is currently thought to be a rickettsia. To determine the relationship between this agent and other haemotrophic bacterial parasites, the 16S rRNA gene of this organism was sequenced. Phylogenetic analysis revealed that this wall-less bacterium is not a rickettsia, but a mycoplasma. This mycoplasma is related closely to several other uncultivated, epierythrocytic mycoplasmas that comprise a recently identified group, the haemotrophic mycoplasmas (haemoplasmas). The haemoplasma group is composed of former Eperythrozoon and Haemobartonella species, as well as newly identified epierythrocytic mycoplasmas. Haemoplasmas parasitize the surface of erythrocytes of a wide variety of vertebrate animal hosts and are transmitted mainly by blood-feeding arthropod vectors. Recognition that E. ovis is a mycoplasma provides a new approach to dealing with this bacterium. It is proposed that E. ovis should be reclassified as Mycoplasma ovis comb. nov.

A child with a history of diarrhea presented with transient anemia, reticolucytosis, and red blood cell fragmentation. Blood pressure and levels of blood platelets, creatinine, and urea were normal, as were results of urinalysis. Escherichia coli harboring genes for Shiga toxin were detected in stool specimens. It is concluded that extraintestinal diseases caused by Shiga toxin-producing bacteria sometimes present without any renal involvement.

The authors describe a 2-month-old female with microangiopathic hemolytic anemia complicating a pertussis pneumonia. The baby was admitted to the Pediatric Intensive Care Unit for monitoring and treatment. Remission occurred without sequelae, but multiple hemotransfusions were needed in the acute phase. This represents the first reported case of such a complication in childhood.

We report a case of an intra-abdominal abscess caused by Listeria monocytogenes in a postoperative patient with Evans syndrome (acquired hemolytic anemia and thrombocytopenia). Focal infections with L. monocytogenes are uncommon but have been reported in immunocompromised patients. A few cases of liver abscess in diabetic patients have also been reported. The present case is significant because of the paucity of previously described focal intra-abdominal infections caused by L. monocytogenes, particularly as a postsplenectomy pathogen.

Introduction: Mycoplasma pneumoniae is a common cause of atypical pneumonia in children and young adults. The infection is generally mild and only a very few patients are admitted to hospital. However, extrapulmonary complications are well recognised--mostly as manifestations from the central nervous system (CNS)., Material and Methods: We describe 21 patients with M. pneumoniae infection seen at Rigshospitalet, Copenhagen, from 1994 to 2000., Results: The patients had fever, headache, myalgia, and cough. Biochemically, they were characterised by leucocytosis, an increased level of C-reactive protein, and infiltrations on the chest x-ray. A total of seven patients developed extrapulmonary complications to the infection in the form of encephalitis (3), polyradiculitis (1), transversel myelitis (1), erythema multiforme (3), cardial arrhythmia (1), and haemolytic anaemia (2). Three patients had more than one complication at the same time., Discussion: The incidence of patients with complications to M. pneumoniae infection was higher than that reported in the literature, probably because these patients are typically submitted to the Department of Infectious Diseases, Rigshospitalet. The pathogenesis of extrapulmonary complications to M. pneumoniae infection is unknown.

We report on a 17-year-old patient with severe bronchiolitis due to Mycoplasma pneumoniae infection. Despite an early 10-day course of clarithromycin, she developed progressive dyspnea, cough, fever, and severe obstructive ventilatory impairment. Sixteen days after onset of the disease a severe hemolytic anemia developed with only cold agglutinins positive at serologic screening. Thoracoscopic lung biopsy revealed diffuse bronchiolitis with suppurative intrabronchiolar inflammation, lymphohistiocytic "cuffing" of the bronchioli, and foam cell aggregates within neighboring alveoli. The infiltrate consisted mainly of CD3+, CD8+ lymphocytes and CD68+ macrophages. The diagnosis of Mycoplasma pneumoniae bronchiolitis was based on repeated complement fixation tests, which turned strongly positive only at day 74 after onset of the disease. Pulmonary function improved slowly under long-term prednisone treatment.

Haemolytic anaemia caused by Clostridium perfringens is a rare complication in patients with neoplastic diseases. According to the literature, our patient seems to be the first patient with underlying malignancy (multiple myeloma) who has survived C. perfringens septicaemia complicated with acute haemolysis and acute anuria. It is concluded that treatment with penicillin should be considered in case of acute haemolytic anaemia, if the patient is febrile and no other obvious cause of the haemolytic condition can be found.

We have used our previously described baboon model of infusion of both a sublethal dose of Escherichia coli and C4b binding protein to assess the impact of inhibiting platelet function with the F(ab')2 fragment of the monoclonal antibody 7E3, directed against the platelet glycoprotein (GP)IIb/IIIa receptor, on the characteristic microvascular changes. At a dose of 0.25 to 0.35 mg/kg bolus plus an infusion of 0.25 to 0.35 mg/kg over 6 hours, c7E3 F(ab')2 had only a minimal impact on fibrinogen consumption and delayed but did not prevent, the development of thrombocytopenia. Treatment with 7E3 F(ab')2, however, produced significant protection from the development of microangiopathic hemolysis and renal insufficiency. Histologic examination supported these observations, with treated animals having fewer schistocytes on blood smear and less evidence of ischemic renal changes. Treated animals also had more rapid recovery of peripheral white blood counts, suggesting a possible protective effect of treatment on ischemic damage to the bone marrow. These data indicate that potent inhibition of platelet function via GPIIb/IIIa receptor blockade can decrease ischemic organ damage in this animal model that has features similar to those found in diffuse intravascular coagulation, hemolytic uremic syndrome, and thrombotic thrombocytopenic purpura.

Clostridium perfringens sepsis with hemolysis following cholecystectomy is a rare complication that has a very high mortality. The best chance for survival is ensured by early diagnosis, prompt initiation of antibiotics, and hyperbaric oxygen therapy if readily available. To our knowledge, this is the first reported case following laparoscopic cholecystectomy.

Two sisters, 2 and 5 years of age, suffered from acute haemolytic anaemia occurring after gastroenteritis with Escherichia coli O157. One patient developed clinical signs of severe and acute intravascular haemolysis and sepsis. She received transfusion and antibiotic therapy. The second patient presented with mild to moderate haemolytic symptoms only. None of them developed renal impairment. In serum of both children, elevated titres of short-lived agglutinins were demonstrated in the indirect haemagglutination assay consisting of sheep erythrocytes coated with lipopolysaccharide from E. coli O157. By immunoblot analysis IgM antibodies against the O157 lipopolysaccharide were demonstrated in the acute phase sera but not in follow up sera taken 2 months after disease. On erythrocyte membranes, adsorption of microbial antigens was detected by use of a pool-immunoglobulin fluorescence test. The immunological status of both patients was normal. Complete recovery from haemolytic disease was observed without further therapy. Microbial antigens attached to the cell surface were assumed to be the pathophysiological cause of E. coli O157 associated haemolytic anaemia in two siblings.

A colony of sphha/sphha mice with congenital hemolytic anemia and an abnormality in erythrocyte spectrin assembly was screened to determine the cause of premature death. Sphha/sphha mice have decreased life span, with 50% of animals dying by 6 months of age. The phenotype of these mutant mice includes moderate anemia (hematocrit: 21 to 28%), reticulocytosis, leukocytosis, lymphocytosis, extensive extramedullary hematopoiesis in spleen and liver, lymph node hyperplasia and membranoproliferative glomerulonephritis. With increased surveillance of this mouse colony, 20 clinically sick anemic mice were evaluated (complete blood counts and cultures of blood), euthanized and necropsied. Compared with anemic mice without clinical signs of disease, sick anemic mice had significantly higher white blood cell counts with only 4 (20%) of 20 animals being severely anemic (hematocrit: 4 to 8%). Blood from 11 (45%) of 20 animals was culture-positive for Pasteurella pneumotropica, Enterococcus, and/or Escherichia coli. In addition to the usual lesions in sphha/sphha mice, sick anemic mice had pneumonitis (95%) with thrombosis and infarction (80%) of one or more organs (spleen, myocardium, pancreas, liver, or bone marrow). The thrombotic tendency that accompanies the chronic hemolytic anemia in sphha/sphha mice, as well as the other clinicopathologic changes in these mutant mice, bears a striking resemblance to some poorly understood sequelae in human patients with sickle cell anemia. This mouse model may be useful in studying the pathophysiology of complications associated with sickle cell anemia in humans.

Friend murine leukemia virus is a replication-competent retrovirus that contains no oncogene and that exerts lytic and leukemogenic properties. Thus, newborn mice inoculated with Friend murine leukemia virus develop severe early hemolytic anemia before appearance of erythroleukemia. To identify the retroviral determinants regulating these effects, we used chimeric infectious constructions and site-directed point mutations between a virulent Friend murine leukemia virus strain and a naturally occurring variant attenuated in lytic and leukemogenic effects. We found that severe hemolytic anemia was always associated with higher numbers of blood reticulocytes with budding retroviral particles. Furthermore, a remarkably conservative leucine to isoleucine change in the extracellular SU component of the retroviral envelope was sufficient to attenuate this lytic effect. Also, this leucine at position 348 of the envelope precursor protein was located within the only stretch of five amino acids that is conserved in the extracellular SU component of all murine, feline, and primate type C and type D retroviral envelopes. This observation suggested an important structural function for this yet undescribed conserved sequence of the envelope. Lastly, we observed that lytic and leukemogenic effects were attenuated by a deletion of a second repeat in the transcriptional enhancer region of the viral long terminal repeats of the variant strain.

Anemia develops in about a fourth of women whose pregnancy is complicated by pyelonephritis, although its exact mechanism has not been defined clearly. In this study of 18 women with antepartum pyelonephritis, although only a third had anemia (hematocrit less than 30 vol/dl), there was evidence for hemolysis in all 18. Specifically there was a mean decrease in hematocrit of 5 vol/dl from admission to discharge. With scanning electron microscopy, we compared erythrocyte morphologic aberrations that were found in women with renal infection with those of normally pregnant women, and the former had significantly increased proportions of echinocytes in particular, but schistocytes and spherocytes were increased also (total 10.3% vs 1.4%, p less than 0.0001). These changes, especially echinocytosis, have been induced in vitro by lipopolysaccharide, and they are known to lead to premature red blood cell destruction in vivo. We conclude that hemolysis with subsequent anemia in pregnant women with pyelonephritis is caused by lipopolysaccharide-induced red blood cell membrane damage.

Viruses have been shown to cause bone marrow aplasia in animals and have been implicated in bone marrow failure in man; however, until recently, a specific link between human viral infection and bone marrow failure has not been proven. In 1975 Cossart and colleagues found a serum parvovirus-like virus (SPLV, sometimes referred to as B19) in human serum. Antibody to this virus is present in the sera of 30-45% of healthy adults (Y. E. Cossart, P. P. Mortimer, unpublished observations). However, evidence for a direct link came from work by Pattison et al. who found five children with transient aplastic crisis of sickle cell disease and evidence of active infection with SPLV. This association was later confirmed in a large series of children with sickle cell disease and aplastic crisis in Jamaica. We have studied the effects of virus-containing material on haematopoiesis, using in vitro colony-forming assays to look for direct evidence for a role of SPLV in bone marrow aplasia. We show here that SPLV-containing sera inhibit erythropoiesis in culture. Moreover, in a child with hereditary spherocytosis who developed transient aplastic crisis, a strong inhibitory effect of the patient's serum on erythropoiesis correlated with the presence of virus.

Murine erythroblastosis virus (MuEV), also called murine leukemia virus-Kirsten, is a member of the murine type-C-RNA leukemia-sarcoma group of oncogenic viruses. Like other members of this group, MuEV can elicit both a hemolytic disorder and an oncogenic response. Neonatal rats infected with MuEV succumb to this hemolytic disorder unless they are treated with the synthetic double-stranded polyribonucleotide, polyinosinic-polycytidylic acid (poly I-poly C). Animals receiving poly I-poly C had markedly reduced levels of virus reproduction as measured by bioassay and electron microscopy. The proliferation of erythroblasts after MuEV infection in animals not receiving poly I-poly C appeared to be an erythropoietin-dependent compensatory response to hemolysis. The hemolysis itself seemed to require virus reproduction in the cell types affected. Administration of poly I-poly C to MuEV-infected rats inhibited virus reproduction and thus may circumvent the hemolytic disease syndrome. The ultrastructure of the virus and of the virus reproduction was also studied.