Noncontiguous finished genome sequence and description of Bacillus testis strain SIT10 sp. nov

Bacillus testis strain SIT10 (= CSUR P1492 = DSMZ 101190) is the new type strain collected from stool from a 2-year-old boy from Senegal during a culturomics study. This Gram-positive bacterium is a facultative anaerobic rod and a member of the Bacillaceae family. We describe here the features of this bacterium, together with the complete genome sequence and annotation. The 3 987 349 bp long genome (one chromosome but no plasmid) with 42.8% GC content contains 4005 protein-coding and 171 sRNA genes, including 19 5S rRNA gene, 15 16S rRNA genes and ten 23S rRNA genes.

Noncontiguous finished genome sequence and description of Bacillus andreraoultii strain SIT1(T) sp. nov

Bacillus andreraoultii strain SIT1^T (= CSUR P1162 = DSM 29078) is the type strain of B. andreraoultii sp. nov. This bacterium was isolated from the stool of a 2-year-old Nigerian boy with a severe form of kwashiorkor. Bacillus andreraoultii is an aerobic, Gram-positive rod. We describe here the features of this bacterium, together with the complete genome sequencing and annotation. The 4 092 130 bp long genome contains 3718 protein-coding and 116 RNA genes.

New Delhi Metallo-beta-lactamase around the world: An eReview using Google Maps

Gram-negative carbapenem-resistant bacteria, in particular those producing New Delhi Metallo-beta-lactamase-1 (NDM-1), are a major global health problem. To inform the scientific and medical community in real time about worldwide dissemination of isolates of NDM-1-producing bacteria, we used the PubMed database to review all available publications from the first description in 2009 up to 31 December 2012, and created a regularly updated worldwide dissemination map using a web-based mapping application. We retrieved 33 reviews, and 136 case reports describing 950 isolates of NDM-1-producing bacteria. Klebsiella pneumoniae (n= 359) and Escherichia coli (n=268) were the most commonly reported bacteria producing NDM-1 enzyme. Several case reports of infections due to imported NDM-1 producing bacteria have been reported in a number of countries, including the United Kingdom, Italy, and Oman. In most cases (132/153, 86.3%), patients had connections with the Indian subcontinent or Balkan countries. Those infected were originally from these areas, had either spent time and/or been hospitalised there, or were potentially linked to other patients who had been hospitalised in these regions. By using Google Maps, we were able to trace spread of NDM-1-producing bacteria. We strongly encourage epidemiologists to use these types of interactive tools for surveillance purposes and use the information to prevent the spread and outbreaks of such bacteria.

Statins limit Rickettsia conorii infection in cells

Recent data suggest that statins may have a beneficial effect during sepsis. In this study, we tested the effect of lovastatin and pravastatin on the cellular culture of Rickettsia conorii using a quantitative plaque assay model associated with an original image analysis algorithm. Statins added at the time of infection did not modify plaque formation, whereas pre-incubation with statins for 48h resulted in a significant 30-68% plaque reduction, depending on the tested compounds and doses. These preliminary findings raise the hypothesis that statins may prevent or moderate rickettsial disease in exposed people.

Spotted fever group rickettsioses in Himachal Pradesh

Rickettsiae are in many places of the world emerging or reemerging pathogens. The spotted fevers group (SFG) composes a large group of tick- and mite-borne zoonotic infections that are caused by closely related rickettsiae. The SFG rickettsiae of Southeast Asia are yet to be identified. Earlier reports have documented the endemicity of rickettsioses among adults in the Himalayan belt but no confirmed case of spotted fever have been reported from this region of India. We present two cases of SFG rickettsioses; from the northern hilly region of India that were confirmed using specific microimmunofluorescence assay.

Q fever osteoarticular infection: four new cases and a review of the literature

Q fever is a worldwide-occurring zoonosis caused by Coxiella burnetii. Better knowledge of the disease and of evolving diagnostics can enable recognition of unusual manifestations. Reported here are four cases of Q fever osteoarticular infections in adults: two cases of Q fever tenosynovitis, which represent the first two reports of this infection, and two cases of Q fever spondylodiscitis complicated by paravertebral abscess. In addition, the literature is reviewed on the 15 previously reported cases of Q fever osteoarticular infection, six of which were vertebral infections. Osteomyelitis is the usual manifestation Q fever osteoarticular infection. Because its onset is frequently insidious, diagnosis is usually delayed. The main differential diagnosis is mycobacterial infection, based on the histological granulomatous presentation of lesions. Whereas serology is the reference diagnostic method for Q fever, detection of C. burnetii in tissue specimens by PCR and cell culture provides useful additional evidence of infection. Culture-negative osteoarticular samples with granulomatous presentation upon histological examination should raise suspicion of Q fever.

Serologic study of rickettsioses among acute febrile patients in central Tunisia

Although Mediterranean spotted or "boutonneuse" fever (MSF) has been documented in central Tunisia, other spotted fever group rickettsioses (SFGR) and typhus group rickettsioses (TGR) have received little attention in our region. We sought to determine the role of rickettsioses, Q fever, ehrlichioses, and bartonelloses among patients with acute fever. The results of this study of 47 persons with acute fever of undetermined origin are reported in this paper. We concluded that SFGR, murine typhus, and acute Q fever are common causes of acute isolate fever in summer in central Tunisia and should be investigated systematically in patients with acute fever of unknown origin.

First Molecular Detection of R. conorii, R. aeschlimannii, and R. massiliae in Ticks from Algeria

Ticks collected in Northern Algeria between May 2001 and November 2003 were tested by PCR for the presence of Rickettsia spp. DNA using primer amplifying gltA and OmpA genes. Three different spotted fever group rickettsias were amplified from these ticks: R. Conorii subsp. P. conorii strain Malish in Rhipicephalus sanguineus, R. aeschlimannii in Hyalomma marginatum, and R. massiliae in Rhipicephalus turanicus. Our results confirm the presence of R. conorii in ticks in Algeria and provide the first detection of R. aeschlimannii and R. massiliae in Algeria.

Causes of acute, undifferentiated, febrile illness in rural Thailand: results of a prospective observational study

The adult patients who, between July 2001 and June 2002, presented at any of five hospitals in Thailand with acute febrile illness in the absence of an obvious focus of infection were prospectively investigated. Blood samples were taken from all of the patients and checked for aerobic bacteria and leptospires by culture. In addition, at least two samples of serum were collected at different times (on admission and 2-4 weeks post-discharge) from each patient and tested, in serological tests, for evidence of leptospirosis, rickettsioses, dengue and influenza. The 845 patients investigated, of whom 661 were male, had a median age of 38 years and a median duration of fever, on presentation, of 3.5 days. Most (76.5%) were agricultural workers and most (68.3%) had the cause of their fever identified, as leptospirosis (36.9%), scrub typhus (19.9%), dengue infection or influenza (10.7%), murine typhus (2.8%), Rickettsia helvetica infection (1.3%), Q fever (1%), or other bacterial infection (1.2%). The serological results indicated that 103 (12.2%) and nine (1%) of the patients may have had double and triple infections, respectively. Leptospirosis and rickettsioses, especially scrub typhus, were thus found to be major causes of acute, undifferentiated fever in Thai agricultural workers.

Genome Comparison Analysis of Molecular Mechanisms of Resistance to Antibiotics in the Rickettsia Genus

In this study we describe molecular mechanisms of resistance to several classes of antibiotics within drug targets by in silico genome comparisons for bacteria of the genus Rickettsia. Apart from the mutations in the rpoB gene in naturally rifampin-resistant Rickettsia species previously reported by our team, we found that typhus group (TG) rickettsiae had a triple amino acid difference in the highly conserved region of the L22 ribosomal protein as compared to the spotted fever group rickettsiae (SFG), which could explain the natural resistance of SFG rickettsia to erythromycin. We found also that the genome of R. conorii contains an aminoglycoside 3'-phosphotransferase. Finally, either folA gene (encoding dihydrofolate reductase) and/or folP gene (encoding dihydropteroate synthase) was missing in the genome of rickettsial strains explaining the natural resistance to cotrimoxazole. Finally, multiple genes encoding for pump efflux were found especially in the genome of R. conorii that could be involved in resistance to antibiotics. Five specific ORFs related to antibiotic resistance have been identified in the genome of R. felis including a streptomycin resistance protein homologue, a class C beta-lactamase, a class D beta-lactamase, a penicillin acylase homologue, and an ABC-type multidrug transporter system. For the first time, using this approach, an experimental beta-lactamase activity has been shown for this bacterium. We believe that whole genome sequence analysis may help to predict several phenotypic characters, in particular resistance to antibiotics for obligate intracellular bacteria.

Prediction of resistance to erythromycin in the genus Rickettsia by mutations in L22 ribosomal protein

OBJECTIVES

Typhus group (TG) rickettsiae are naturally susceptible to erythromycin whereas spotted fever group (SFG) rickettsioses are not. The aim of this study was to compare in silico genetic determinants known to be associated with resistance to macrolide compounds.

METHODS AND RESULTS

Available sequences of the 23S RNA gene, and L4 and L22 ribosomal proteins of rickettsial strains were aligned and compared using in silico methods. Although there were no sequence differences in domain V of the 23S RNA gene and in the conserved region of the L4 ribosomal protein gene, we found that TG rickettsiae had a triple amino acid difference in the highly conserved region of the L22 ribosomal protein compared with the SFG rickettsiae.

CONCLUSIONS

We believe that the triple amino acid difference in the L22 ribosomal protein found in this study may explain the difference in susceptibility to erythromycin among the Rickettsia genus. Genome analysis may help to predict possible molecular mechanisms of resistance for fastidious and intracellular bacteria and cloning and expression of such proteins should be investigated in the future in order to prove our hypothesis.

Is Q fever an emerging infection in Turkey?

Between 4 May and 8 August 2002,46 cases of acute fever were reported near the Black Sea region in northern Turkey. The infection was treated rapidly and successfully with tetracyclines, so clinical diagnosis of rickettsial or ehrlichial infection was considered. Analysis of serum and blood samples taken from 19 patients identified the causative organism as Coxiella burnetii; 7 cases were reported as acute Q fever and 8 as seropositive for past infection. The most common clinical symptoms among the acute cases were vomiting (100.0%), nausea (85.7%), diarrhoea (57.1%), fever (42.9%), abdominal pain (42.9%) and headache (42.9%). Liver enzymes were elevated in all patients. It is considered that epidemiological investigation for Q fever will be essential in the affected region in future.

Molecular evaluation of antibiotic susceptibility of Tropheryma whipplei in axenic medium

OBJECTIVES AND METHODS

Whipple's disease is a rare multisystem chronic infection, involving the intestinal tract as well as various other organs. Tropheryma whipplei is a slow-growing facultative intracellular bacterium that remains poorly understood. In vitro antibiotic susceptibility testing has previously been assessed in cells using a real-time quantitative PCR assay. In this study, we have evaluated the antibiotic susceptibility of three strains of T. whipplei grown in axenic medium using the same assay.

RESULTS

The active compounds in axenic medium were doxycycline, macrolide compounds, penicillin G, streptomycin, rifampicin, chloramphenicol, thiamphenicol, teicoplanin, vancomycin, amoxicillin, gentamicin, aztreonam, levofloxacin and ceftriaxone, with MICs in the range 0.06-1 mg/L. Cefalothin was less active, with MICs in the range 2-4 mg/L. We found that co-trimoxazole was active with MICs in the range 0.5-1 mg/L, and sulfamethoxazole alone was active with MICs in the range 0.5-1 mg/L. MICs of trimethoprim varied from 64-128 mg/L.

CONCLUSIONS

Co-trimoxazole was effective in vitro, but this activity was due to sulfamethoxazole alone. These results were in accordance with the fact that T. whipplei does not contain the encoding gene for dihydrofolate reductase, the target for trimethoprim.

Evaluation of antibiotic susceptibilities of Ehrlichia canis, Ehrlichia chaffeensis, and Anaplasma phagocytophilum by real-time PCR

We determined MICs of antibiotics against Anaplasma phagocytophilum, Ehrlichia chaffeensis, and Ehrlichia canis by real-time quantitative PCR. The doubling times of the organisms were established: 19 h for E. chaffeensis, 26 h for A. phagocytophilum, and 28 h for E. canis. In comparison to the reference method for determining sensitivities, which uses Diff-Quick staining, our PCR assay was very sensitive and specific. We confirmed that doxycycline and rifampin are highly active against these bacteria and found variable susceptibilities to fluoroquinolones; A. phagocytophilum was susceptible, but E. canis and E. chaffeensis were only partly susceptible. Beta-lactam compounds, cotrimoxazole, macrolide compounds, and telithromycin showed no activity against any of the three organisms. Thiamphenicol was found to be more active than chloramphenicol. For the first time, we showed that these three species have numerous point mutations in their 23S RNA genes, with those at positions 754, 2057, 2058, 2059, and 2611 (Escherichia coli numbering) known to confer resistance to macrolide compounds in other bacteria. The role of each of these mutations in resistance to these drugs should be investigated in the future. Our study confirms previous reports that quantitative PCR is a reliable method for determining antibiotic susceptibility; therefore, it might be useful for screening new drugs.

Detection of Bartonella quintana by direct immunofluorescence examination of blood smears of a patient with acute trench fever

We report a case of Bartonella quintana acute symptomatic infection in a homeless man, presenting as a typical trench fever. B. quintana has been retrieved in erythrocytes in large clusters and in erythroblasts. Direct immunofluorescence of blood smears allows a rapid diagnosis.

Concomitant or consecutive infection with Coxiella burnetii and tickborne diseases

BACKGROUND

Q fever is a worldwide zoonosis caused by Coxiella burnetii, which can be isolated from ticks. Reports of people with both Q fever and other tickborne diseases are rare. In this study, we describe 6 patients with Q fever who were infected with 1 of the following tickborne pathogens: Rickettsia conorii (2 patients), Rickettsia slovaca (2), Rickettsia africae (1), and Francisella tularensis (1).

METHODS

Diagnoses were made on the basis of results of microimmunofluorescence assays for detection of C. burnetii, R. conorii, R. slovaca, R. africae, and F. tularensis antigens. Cross-adsorption studies and Western blots were used to confirm dual infections.

RESULTS

Among the 6 cases presented, 3 were probably due to a concomitant infection after a tick bite, whereas the remaining 3 were more likely consecutive infections.

CONCLUSIONS

Because acute Q fever is often asymptomatic, we recommend that patients infected with the tickborne pathogens mentioned above also undergo routine testing for concurrent infections with C. burnetii.

Case reports: scrub typhus during pregnancy in India

Scrub typhus, caused by Orientia tsutsugamushi, is a rural zoonosis endemic in the Asian Pacific region. Doxycycline and chloramphenicol, the recommended drugs for treating this infection, may not be safe during pregnancy. We report on 5 patients with scrub typhus during pregnancy who were seen in India between October 2001 and February 2002. Four of the 5 women were treated initially with ciprofloxacin. Three women had stillbirths, 1 an abortion and 1 a low birthweight baby, which suggests that ciprofloxacin should not be used for treating pregnant women and that scrub typhus leads to severe adverse effects during pregnancy. Randomized controlled trials are urgently needed to ascertain the optimal drug choice, given that currently recommended drugs are contraindicated in pregnant women.

Simplified serological diagnosis of endocarditis due to Coxiella burnetii and Bartonella

We tested a single-step serological assay against Coxiella burnetii and Bartonella species and found a sensitivity of 100%, and a positive predictive value of 98% for the diagnosis of blood culture-negative endocarditis (BCNE). This assay should be considered as a possible commercial test for the diagnosis of BCNE.

First isolation of Rickettsia conorii from humans in the Trakya (European) region of Turkey

In the Trakya region of Turkey, located in the European part of the country, presumptive cases of Mediterranean spotted fever have been diagnosed and treated every summer since the beginning of the 1990s. The aim of this prospective study was to isolate and identify the rickettsial strains from blood samples of 11 patients and from skin biopsies of 10 of these 11 patients with the diagnosis of spotted fever in the Trakya region of Turkey in 2003. Immunofluorescence assay was performed with acute-phase and convalescent-phase serum samples of 11 patients. All patients had significant antibody titers against spotted fever group rickettsiae. Rickettsia conorii was isolated from the skin biopsies of three of ten patients and was also demonstrated by polymerase chain reaction in skin biopsies of nine of ten patients. In southeastern Europe, the Balkan Peninsula (including the Trakya region of Turkey) is an area where arthropods are endemic and where new arthropod-borne infections can be detected.

Real-time PCR for universal antibiotic susceptibility testing

OBJECTIVES

Determination of bacterial antimicrobial susceptibility is usually performed using phenotypic methods. In this study, we developed a universal 16S rRNA and rpoB quantitative PCR assay for susceptibility testing of bacteria commonly isolated in clinical microbiology laboratories.

METHODS

Antibiotic susceptibilities for 24 bacterial strains of various species were tested by real-time quantitative PCR assay and by conventional methods. Quantification of DNA copies of either the 16S RNA genes or rpoB were recorded over time in the presence or absence of antibiotics to determine the bacterial growth kinetics and the optimal testing time.

RESULTS

Molecular results for antibiotic susceptibility or resistance were in accordance with those obtained using a standard macrodilution broth assay. The method was reproducible, sensitive and rapid (2 h for Gram-negative bacilli and 4 h for Gram-positive cocci). Moreover, this assay was also able to determine the antibiotic susceptibilities of fastidious bacteria, such as mycobacteria, within 5 days.

CONCLUSIONS

These results demonstrate that molecular detection of bacteria could be more rapid than phenotypic methods for antibiotic susceptibility testing.

Correlation between serum doxycycline concentrations and serologic evolution in patients with Coxiella burnetii endocarditis

The recommended treatment for Q fever endocarditis is a combination of doxycycline and hydroxychloroquine. We found a correlation between serum doxycycline concentrations and decreases in levels of phase 1 Coxiella burnetii antibodies, in 24 patients with Q fever endocarditis. Patients who had a >2-fold decrease in levels of phase 1 antibodies had serum doxycycline concentrations higher than those of the other patients (mean+/-SD, 5.29+/-1.75 vs. 3.14+/-1.40 microg/mL; P=.003). We recommend adjusting the posology of doxycycline to achieve a serum concentration of at least 5 microg/mL.

Detection by immunofluorescence assay of Bartonella henselae in lymph nodes from patients with cat scratch disease

Laboratory diagnosis of Bartonella henselae infections can be accomplished by serology or PCR assay on biopsy samples. The purpose of our work was to assess immunofluorescence detection (IFD) in lymph node smears using a specific monoclonal antibody directed against B. henselae and a commercial serology assay (IFA) compared with PCR detection. Among 200 lymph nodes examined from immunocompetent patients, 54 were positive for B. henselae by PCR, of which 43 were also positive by IFD. Among the 146 PCR-negative lymph nodes, 11 were positive by IFD. Based on PCR results, the specificity of this new technique was 92.5%, the sensitivity was 79.6%, and the positive predictive value was 79.6%. At a cutoff titer of 64, the sensitivity of the IFA was 86.8% and the specificity was 74.1%. Diagnosis of cat scratch disease (CSD) may be improved, with a specificity of 100%, when the two tests (IFD and IFA) were negative; the sensitivity was 97.4% if one of the two tests was positive. Since PCR-based detection with biopsy samples is available only in reference laboratories, we suggest using IFD coupled with the commercial serology test for the diagnosis of CSD.

Outbreak of scrub typhus in southern India during the cooler months

Orientia tsutsugamushi, the agent of scrub typhus, is a strict intracellular bacterium which is found in many parts of Asia including India. During the past few years, the number of patients with rickettsial infection and scrub typhus has increased, especially during the cooler months. We report in this study a recent outbreak of scrub typhus recorded during the cooler months (October 2001 to February 2002) in patients admitted to our hospital with acute febrile illness associated with diverse signs and symptoms. Overall, 28 patients were clinically and serologically confirmed to have scrub typhus. Fever for more than one week was the only common manifestation. Myalgias was the next most common feature (52%), and rash was observed in only 22% of the cases. Seventeen patients treated with doxycycline recovered in 1 to 3 days, as well as two patients who received chloramphenicol. In five patients who received ciprofloxacin, fever subsided only after five days. Finally three patients (10.7%) died, including one patient treated with doxycycline. These data indicate that scrub typhus is a reemerging infectious disease in India with a possibility of drug resistance. This reemergence emphasizes the need for further prospective studies to design effective control measures.

Q Fever in human and livestock populations in Oman

In 2000, Q fever was documented for the first time in the Sultanate of Oman in two patients, one with chronic pericarditis and the other with acute pneumonia. In 2001, a study of a randomly selected group of 102 adult patients from different provinces in northern Oman, presenting to the University Hospital in Muscat with unrelated conditions (e.g., diabetes mellitus, ischemic heart disease), revealed that 10 (9.8%) were seropositive for previous Coxiella burnetii infection. Examination of sera from a randomly selected group of 54 healthy goats from eight different herds from three different provinces of Oman, obtained by the Veterinary Research Center in Muscat, revealed that 28 (52%) had been infected, and 5 sheep, each from one of four herds, were seropositive for C. burnetii. We suspect that Q fever is widely prevalent in human populations in Oman, and that infection is widespread in goat, and probably sheep and other livestock populations, throughout the country.

Cat scratch disease with lymphadenitis, vertebral osteomyelitis, and spleen abscesses

In this report we describe a 30-year old male patient with vertebral osteomyelitis and spleen abscesses with cat scratch disease. The diagnosis was made on the basis of molecular detection of Bartonella henselae either on lymph node biopsies or on bone biopsy, histology of the lymph node, serology using either our in-house microimmunofluorescence assay or a commercial kit (Focus Technologies). Immunofluorescent detection was also performed directly on slide appositions using a monoclonal antibody. Treatment consisted of administration of antibiotics with rapid clinical improvement and a stabilization of skeletal lesions on the magnetic resonance imaging performed three months later. Twenty two other cases of this unusual manifestation associated with cat scratch disease have been reported in the literature and are reviewed here. Our case represents the second case of osteomyelitis associated with cat scratch disease in which B. henselae has been specifically identified as the etiological agent using several direct and indirect methods.

Molecular evaluation of antibiotic susceptibility: Tropheryma whipplei paradigm

Tropheryma whipplei, the agent of Whipple's disease, grows fastidiously only in cell cultures without plaque production, and only three strains have been passaged. The formation of bacterial clumps in the supernatant precludes enumeration of viable bacteria and MIC determination. We evaluated the bacteriostatic effects of fluoroquinolones against two T. whipplei isolates by measuring the inhibition of the DNA copy number increase by real-time quantitative PCR. The analysis of the T. whipplei genome database allowed the identification not only of the gyrA gene but also the parC gene encoding the alpha subunit of the natural fluoroquinolone targets DNA gyrase (GyrA) and topoisomerase IV (ParC), respectively. The parC gene was detected in actinobacteria for the first time. High ciprofloxacin MICs (4 and 8 micro g/ml) were correlated with the presence in T. whipplei GyrA and ParC sequences with an alanine residue at positions 83 and 80 (Escherichia coli numbering), respectively. Alanines at these positions have previously been associated with increased fluoroquinolone resistance in E. coli and mycobacteria. However, the MIC of levofloxacin was low (0.25 micro g/ml). The same T. whipplei GyrA and ParC sequences were found in two other cultured strains and in nine uncultured tissue samples from Whipple's disease patients, allowing one to speculate that T. whipplei is naturally relatively resistant to fluoroquinolones.

Acute acalculous cholecystitis associated with Q fever: report of seven cases and review of the literature

Q fever is a worldwide-occurring zoonosis caused by Coxiella burnetii. There are various clinical manifestations of acute Q fever, of which acute cholecystitis is a very rare clinical presentation. This study reports seven cases of acute cholecystitis associated with Coxiella burnetii and reviews two other cases from the literature. All patients were admitted to hospital for fever and abdominal pain in the right upper quadrant. Abdominal echography showed a distended gallbladder with biliary sludge without concrements in eight cases and with a single stone in one case. Diagnosis was made by specific serological investigation (microimmunofluorescence assay) for Coxiella burnetii. All nine patients were cured, six after laparoscopic cholecystectomy and three with antibiotics only. Histological examination of the gallbladders showed inflammation in five cases, although Coxiella burnetii was not detected by immunohistochemistry. The results show that laboratory investigations in patients admitted to hospital for symptoms consistent with acute acalculous cholecystitis should include a systematic search for Coxiella burnetii.

Comparison of in-house and commercial slides for detection by immunofluorescence of immunoglobulins G and M against Bartonella henselae and Bartonella quintana

We compared the sensitivities and specificities of indirect fluorescent antibody tests developed in our laboratory and commercially available from Focus Technologies (FT; formerly MRL Diagnostic) for detection of serum antibodies to Bartonella spp. Serum samples tested were from patients with culture- or PCR-confirmed Bartonella quintana or B. henselae infections causing cat scratch disease (CSD), chronic bacteremia, or endocarditis. At a cutoff titer of 64, the FT test had higher sensitivity than our in-house test in detecting anti-B. henselae immunoglobulin G (IgG) antibodies in CSD patients (91.2 versus 52.9%; P < 0.001). The specificity in serum samples from 85 control patients was, however, lower with the FT test (87%) than with the in-house test (98.8%) (P = 0.002). A cutoff titer of 128 improves the specificity for the FT test but lowers the sensitivity to 85%. For patients infected with B. henselae, our in-house test, but not the FT test, enabled endocarditis to be detected more reliably. With the in-house test, titers of IgG against B. henselae of >/=1,024 were found only in endocarditis patients and not in CSD patients. With the FT test, 19.1% of CSD patients had titers of IgG against B. henselae of >/=1,024 (P < 0.001). Our in-house technique also improved detection of anti-B. quintana antibodies in homeless patients with endocarditis. IgG titers of >/=1,024 were present in 75% of serum samples, but only in 16.7% of serum samples with the FT test (P = 0.004). Since each test has advantages over the other, the serological diagnosis of Bartonella infections would benefit if both tests were used concurrently.

Iron chelators as antimalarial agents: in vitro activity of dicatecholate against Plasmodium falciparum

The present study was undertaken to explore the antimalarial effect of a series of dicatecholate iron chelators. They may be made more or less lipophilic by increasing or reducing the length of the R substituent on the nitrogen. In vitro activity against the W2 and 3D7 clones of Plasmodium falciparum, toxicity on Vero cells and toxicity on uninfected erythrocytes by measure of the released haemoglobin were assessed for each compound. These findings were compared with the ability of iron(III), iron(II) and ferritin to reverse the inhibitory effect of catecholates. This study shows that increased lipid solubility of catecholate iron chelators does not lead to improved antimalarial activity. However, their activity is well correlated with their interaction with iron and with their toxicity against Vero cells. This study demonstrates a potent antimalarial effect of FR160 (R = C9H19) on five different strains of P. falciparum in vitro. FR160 inhibited parasite growth with an IC50 between 0.8 and 1.5 micro M. The effects of FR160 on mammalian cells were minimal compared with those obtained with malaria parasites. FR160 acted on parasites at considerably higher rates than desferrioxamine, and at all stages of parasite growth. The drug was more effective at the late trophozoite and young schizont stages, although FR160 affected rings and schizonts as well. Ascorbic acid, a free radical scavenger, reduced the activities of FR160 and artesunate. FR160 might induce formation of free radicals, which could explain why FR160 antagonized the effects of artesunate and dihydroartemisinin.

Immunofluorescent detection of intraerythrocytic Bartonella henselae in naturally infected cats

To determine the presence of Bartonella henselae bacteremia in six cats, we compared isolation using blood culture with direct immunofluorescence on blood smears. Three cats that were positive by blood culture were also positive by direct immunofluorescence, and laser confocal microscopy confirmed the intraerythrocytic location of B. henselae.

Bacteriostatic and bactericidal activities of moxifloxacin against Coxiella burnetii

The in vitro activity of moxifloxacin against Coxiella burnetii was compared to those of pefloxacin, ofloxacin, and doxycycline. MICs of moxifloxacin ranged from 0.5 to 1 microg/ml for the Nine Mile, Priscilla, and Q212 strains. Moxifloxacin was not bactericidal against C. burnetii at 4 microg/ml.

Bactericidal effect of antibiotics on Bartonella and Brucella spp.: clinical implications

The species Bartonella and Brucella are phylogenetically closely related bacteria, both of which can produce chronic infections in humans that are difficult to cure with antibiotics. MICs of antibiotics for both species correlate poorly with the in vivo efficacy of the antibiotics. In this study we have determined MBCs of several antibiotics for this group of pathogens. Only the aminoglycosides were bactericidal, and this correlates well with the usefulness of these antibiotics for the therapy of human brucellosis and chronic Bartonella spp. infections such as endocarditis. Our data indicate that current clinical experience in treating brucellosis may help to define better the optimum antibiotic therapy for Bartonella-related diseases.

In vitro activities of telithromycin (HMR 3647) against Rickettsia rickettsii, Rickettsia conorii, Rickettsia africae, Rickettsia typhi, Rickettsia prowazekii, Coxiella burnetii, Bartonella henselae, Bartonella quintana, Bartonella bacilliformis, and Ehrlichia chaffeensis

In vitro activities of telithromycin compared to those of erythromycin against Rickettsia spp., Bartonella spp., Coxiella burnetii, and Ehrlichia chaffeensis were determined. Telithromycin was more active than erythromycin against Rickettsia, Bartonella, and Coxiella burnetii, with MICs of 0.5 microg/ml, 0.003 to 0.015 microg/ml, and 1 microg/ml, respectively, but was inactive against Ehrlichia chaffeensis.

In vitro susceptibilities of 27 rickettsiae to 13 antimicrobials

The MICs of 13 antibiotics (doxycycline, thiamphenicol, rifampin, amoxicillin, gentamicin, co-trimoxazole, ciprofloxacin, pefloxacin, ofloxacin, erythromycin, josamycin, clarithromycin, and pristinamycin) were determined for 27 available rickettsial species or strains. We used two in vitro cell culture methods described previously: the plaque assay and the microplaque colorimetric assay. Our results confirm the susceptibilities of rickettsiae to doxycycline, thiamphenicol, and fluoroquinolones. Beta-lactams, aminoglycosides, and cotrimoxazole were not active. Typhus group rickettsiae were susceptible to all macrolides tested, whereas the spotted fever group rickettsiae, R. bellii, and R. canada were more resistant, with josamycin, a safe alternative for the treatment of Mediterranean spotted fever, being the most effective compound. Strain Bar 29, R. massiliae, R. montana, R. aeschlimannii, and R. rhipicephali, which are members of the same phylogenetic subgroup, were more resistant to rifampin than the other rickettsiae tested. Heterogeneity in susceptibility to rifampin, which we report for the first time, may explain in vivo discrepancies in the effectiveness of this antibiotic for the treatment of rickettsial diseases. We hypothesize that rifampin resistance and erythromycin susceptibility may reflect a divergence during the evolution of rickettsiae.