In vitro susceptibility of Bartonella species to 17 antimicrobial compounds: comparison of Etest and agar dilution

Cryptogenic hepatitis patients have a higher Bartonella sp.-DNA detection in blood and skin samples than patients with non-viral hepatitis of known cause

Background

This study aimed to assess the prevalence of Bartonella sp.-DNA detection in blood and skin samples from patients with non-viral end-stage liver disease awaiting liver transplantation.

Methodology/Principal findings

Blood samples and healthy skin fragments from 50 patients were tested using microbiological and molecular methods. Fifteen patients had cryptogenic hepatitis (CH) and 35 had alcoholic, drug-induced or autoimmune liver disease. DNA was extracted from whole blood and liquid culture samples, isolates, and skin fragments. Thirteen of the 50 patients (26%) had Bartonella henselae DNA detection in their blood (9/50) and/or skin (5/50) samples. Colonies were isolated in 3/50 (6%) and infection was detected in 7/50 (14%) of the 50 patients. B. henselae-DNA detection was more prevalent in patients with CH than in other patients (p = 0.040). Of 39 patients followed-up for at least two years, a higher mortality rate was observed among patients with CH infected with B. henselae (p = 0.039).

Conclusions/Significance

Further studies assessing the role of B. henselae infection in the pathogenesis of hepatitis patients must be urgently conducted.

One in four patients with end-stage liver disease awaiting liver transplantation for hepatitis of non-viral origin had documented B. henselae-DNA detection and cryptogenic hepatitis patients have a higher bacterium molecular detection than patients with non-viral hepatitis of known cause.

Antibiotic Susceptibility of Bartonella Grown in Different Culture Conditions

Bartonellosis is caused by a Gram-negative intracellular bacterium with a zoonotic transmission. The disease, caused by any of several genospecies of Bartonella can range from a benign, self-limited condition to a highly morbid and life-threatening illness. The current standard of care antibiotics are generally effective in acute infection; these include azithromycin or erythromycin, doxycycline, gentamicin, rifampin, and ciprofloxacin. However, treatment of chronic infection remains problematic. We tested six different antibiotics for their ability to stop the growth of Bartonella sp. in the standard insect media and in an enrichment media. All antibiotics (ceftriaxone, doxycycline, gentamycin, azithromycin, ampicillin, and azlocillin) had minimum inhibitory concentrations (MICs) below 0.5 µg/mL in the BAPGM enrichment media but were ineffective at inhibiting growth when the standard insect media was used. Azlocillin was the most potent, with a MIC of 0.01 µg/mL. When Bartonella was tested under intracellular growth conditions, none of the antibiotics were efficacious singly. However, growth inhibition was observed when azlocillin and azithromycin were combined. These studies illustrate the impact of growth medium and intracellular environment on antibiotic susceptibility testing and indicate that azlocillin combined with azithromycin may be an effective drug combination for the treatment of Bartonellosis.

Clinical profile and visual outcome of intraocular inflammation associated with cat-scratch disease in Japanese patients

PURPOSE

To evaluate intraocular inflammation in Japanese patients with cat-scratch disease (CSD).

STUDY DESIGN

Retrospective clinical chart review.

PATIENTS AND METHODS

The cases of 15 consecutive patients (19 affected eyes) in Kochi Prefecture, Japan who were serologically positive for Bartonella henselae or Bartonella quintana infection in association with intraocular inflammation were reviewed. The clinical manifestations, ocular complications, and treatment modalities were recorded. The clinical charts and photographic records were also reviewed for evidence of optic disc lesions, macular star, foci of chorioretinitis, and other findings.

RESULTS

Thirteen patients reported fever before or at the time of the initial presentation. Ten of 11 patients with decreased visual acuity manifested neuroretinitis, and the remaining patient showed retinochoroiditis with macular involvement. One patient with a visual field defect manifested branch retinal artery occlusion. Three patients without visual disturbance presented with fever of unknown cause. Discrete white retinal or retinochoroidal lesions were the most common findings (84% of eyes, 87% of patients), followed by retinal hemorrhage (63% of eyes, 80% of patients), optic disc lesions (63% of eyes, 73% of patients), serous retinal detachment (53% of eyes, 67% of patients), and macular star (47% of eyes, 60% of patients).

CONCLUSION

White retinal or retinochoroidal foci were the most common ocular posterior segment manifestations of CSD in this patient population. A diagnosis of CSD should be suspected in patients with fever and chorioretinal white spots, and the absence of neuroretinitis or macular star does not exclude the possibility of intraocular inflammation in CSD.

Ocular complications of cat scratch disease

Cat scratch disease (CSD) in humans is caused by infection with Bartonella henselae or other Bartonella spp. The name of the disease reflects the fact that patients frequently have a history of contact (often involving bites or scratches) with infected cats. Patients with CSD typically develop lesions at the site where the skin is broken together with regional lymphadenopathy but may go on to exhibit systemic symptoms and with deep-seated infections at a range of sites including the eye. Patients with CSD may present with a range of inflammatory eye conditions, including Parinaud's oculoglandular syndrome, neuroretinitis, multifocal retinitis, uveitis and retinal artery occlusion. Bartonella spp. are fastidious bacteria that are difficult to culture from clinical specimens so microbiological diagnosis is frequently made on the basis of positive serology for anti-Bartonella antibodies or detection of bacterial DNA by PCR. Due to the lack of clinical trials, the evidence base for optimal management of patients with CSD-associated eye infections (including the role of antibiotics) is weak, being derived from single reports or small, uncontrolled case series.

Essential Oils with High Activity against Stationary Phase Bartonella henselae

Bartonella henselae is a fastidious Gram-negative intracellular bacterium that can cause cat scratch disease, endocarditis in humans and animals, as well as other complications, leading to acute or chronic infections. The current treatment for Bartonella infections is not very effective due to antibiotic resistance and also persistence. To develop better therapies for persistent and chronic Bartonella infections, in this study, with the help of SYBR Green I/PI viability assay, we performed a high-throughput screening of an essential oil library against the stationary phase B. henselae. We successfully identified 32 essential oils that had high activity, including four essential oils extracted from Citrus plants, three from Origanum, three from Cinnamomum, two from Pelargonium, and two from Melaleuca, as well as frankincense, ylang-ylang, fir needle, mountain savory (winter), citronella, spearmint, elemi, vetiver, clove bud, allspice, and cedarwood essential oils. The minimal inhibitory concentration (MIC) determination of these 32 top hits indicated they were not only active against stationary phase non-growing B. henselae but also had good activity against log-phase growing B. henselae. The time-kill assay showed 13 active hits, including essential oils of oregano, cinnamon bark, mountain savory (winter), cinnamon leaf, geranium, clove bud, allspice, geranium bourbon, ylang-ylang, citronella, elemi, and vetiver, could eradicate all stationary phase B. henselae cells within seven days at the concentration of 0.032% (v/v). Two active ingredients, carvacrol and cinnamaldehyde, of oregano and cinnamon bark essential oils, respectively, were shown to be very active against the stationary phase B. henselae such that they were able to eradicate all the bacterial cells even at the concentration ≤ 0.01% (v/v). More studies are needed to identify the active components of some potent essential oils, decode their antimicrobial mechanisms, and evaluate their activity against Bartonella infections in animal models.

Identification of FDA-Approved Drugs with Activity against Stationary Phase Bartonella henselae

Bartonella henselae can cause various infections in humans, ranging from benign and self-limiting diseases to severe and life-threatening diseases as well as persistent infections that are difficult to treat. To develop more effective treatments for persistent Bartonella infections, in this study, we performed a high-throughput screen of an FDA-approved drug library against stationary phase B. henselae using the SYBR Green I/propidium iodide (PI) viability assay. We identified 110 drug candidates that had better activity against stationary phase B. henselae than ciprofloxacin, and among the top 52 drug candidates tested, 41 drugs were confirmed by microscopy to have higher activity than the current frontline antibiotic erythromycin. The identified top drug candidates include pyrvinium pamoate, daptomycin, methylene blue, azole drugs (clotrimazole, miconazole, sulconazole, econazole, oxiconazole, butoconazole, bifonazole), aminoglycosides (gentamicin and streptomycin, amikacin, kanamycin), amifostine (Ethyol), antiviral Lopinavir/ritonavir, colistin, nitroxoline, nitrofurantoin, verteporfin, pentamidine, berberine, aprepitant, olsalazine, clinafloxacin, and clofoctol. Pyrvinium pamoate, daptomycin, methylene blue, clotrimazole, and gentamicin and streptomycin at their respective maximum drug concentration in serum (C_max) had the capacity to completely eradicate stationary phase B. henselae after 3-day drug exposure in subculture studies. While the currently used drugs for treating bartonellosis, including rifampin, erythromycin, azithromycin, doxycycline, and ciprofloxacin, had very low minimal inhibitory concentration (MIC) against growing B. henselae, they had relatively poor activity against stationary phase B. henselae, except aminoglycosides. The identified FDA-approved agents with activity against stationary phase B. henselae should facilitate development of more effective treatments for persistent Bartonella infections.

Cat Scratch Disease: Not a Benign Condition

PURPOSE

Describe a case series of ocular Cat-scratch-disease (CSD) with vision-threatening findings and poor outcomes, indicating severity of disease.

METHODS

Retrospective case series from the Uveitis Department of São Paulo Federal University from 2011 to 2015.

RESULTS

In this period, six eyes of four patients had confirmed diagnosis of CSD. Two were male and two female. Mean age was 24.8 years old [7-45]. Two had bilateral disease. Visual acuity at presentation ranged from no light perception to 20/25. Three patients were treated with doxycycline and one with clarithromycin and prednisone. Visual outcome after treatment ranged from counting fingers to 20/20: 5/6 eyes had final visual acuity of less than 20/40 and 3/6 had final visual acuity equal or less than 20/400.

CONCLUSION

Although usually described as a benign disease with spontaneous resolution, CSD can present with atypical manifestations such as vascular angiomatous lesions, serous retinal detachment, and vascular occlusion syndromes, carrying a severe course and guarded prognosis.

Chronic Lyme Disease and Co-infections: Differential Diagnosis

In Lyme disease concurrent infections frequently occur. The clinical and pathological impact of co-infections was first recognized in the 1990th, i.e. approximately ten years after the discovery of Lyme disease. Their pathological synergism can exacerbate Lyme disease or induce similar disease manifestations. Co-infecting agents can be transmitted together with Borrelia burgdorferi by tick bite resulting in multiple infections but a fraction of co-infections occur independently of tick bite. Clinically relevant co-infections are caused by Bartonella species, Yersinia enterocolitica, Chlamydophila pneumoniae, Chlamydia trachomatis, and Mycoplasma pneumoniae. In contrast to the USA, human granulocytic anaplasmosis (HGA) and babesiosis are not of major importance in Europe. Infections caused by these pathogens in patients not infected by Borrelia burgdorferi can result in clinical symptoms similar to those occurring in Lyme disease. This applies particularly to infections caused by Bartonella henselae, Yersinia enterocolitica, and Mycoplasma pneumoniae. Chlamydia trachomatis primarily causes polyarthritis. Chlamydophila pneumoniae not only causes arthritis but also affects the nervous system and the heart, which renders the differential diagnosis difficult. The diagnosis is even more complex when co-infections occur in association with Lyme disease. Treatment recommendations are based on individual expert opinions. In antibiotic therapy, the use of third generation cephalosporins should only be considered in cases of Lyme disease. The same applies to carbapenems, which however are used occasionally in infections caused by Yersinia enterocolitica. For the remaining infections predominantly tetracyclines and macrolides are used. Quinolones are for alternative treatment, particularly gemifloxacin. For Bartonella henselae, Chlamydia trachomatis, and Chlamydophila pneumoniae the combination with rifampicin is recommended. Erythromycin is the drug of choice for Campylobacter jejuni.

Chronic Bartonellosis in cats: what are the potential implications?

PRACTICAL RELEVANCE

Bartonellae are small, vector-transmitted Gram-negative intracellular bacteria that are well adapted to one or more mammalian reservoir hosts. Cats are the natural reservoir for Bartonella henselae, which is a (re-)emerging bacterial pathogen. It can cause cat scratch disease in humans and, in immunocompromised people, may lead to severe systemic diseases, such as bacillary angiomatosis. Cats bacteraemic with B henselae constitute the main reservoir from which humans become infected. Most cats naturally infected with B henselae show no clinical signs themselves, but other Bartonella species for which cats are accidental hosts appear to have more pathogenicity.

GLOBAL IMPORTANCE

Several studies have reported a prevalence of previous or current Bartonella species infection in cats of up to 36%. B henselae is common in cats worldwide, and bacteraemia can be documented by blood culture in about a quarter of healthy cats. The distribution of B henselae to various parts of the world has largely occurred through humans migrating with their pet cats. The pathogen is mainly transmitted from cat to cat by fleas, and the majority of infected cats derive from areas with high flea exposure. No significant difference in B henselae prevalence has been determined between male and female cats. In studies on both naturally and experimentally infected cats, chronic bacteraemia has mainly been found in cats under the age of 2 years, while those over 2 years of age are rarely chronically bacteraemic.

EVIDENCE BASE

This article reviews published studies and case reports on bartonellosis to explore the clinical significance of the infection in cats and its impact on humans. The article also discusses possible treatment options for cats and means of minimising the zoonotic potential.

Studies on the antimicrobial properties of N-acylated ciprofloxacins

Fluoroquinolone antibiotics have been a mainstay in the treatment of bacterial diseases. The most notable representative, ciprofloxacin, possesses potent antimicrobial activity; however, a rise in resistance to this agent necessitates development of novel derivatives to prolong the clinical lifespan of these antibiotics. Herein we have synthesized and analyzed the antimicrobial properties of a library of N-acylated ciprofloxacin analogues. We find that these compounds are broadly effective against Gram-positive and Gram-negative bacteria, with many proving more effective than the parental drug, and several possessing MICs ≤1.0 μg/ml against methicillin-resistant Staphylococcus aureus and Bartonella species. An analysis of spontaneous mutation frequencies reveals very low potential for resistance in MRSA compared to existing fluoroquinolones. Mode of action profiling reveals that modification of the piperazinyl nitrogen by acylation does not alter the effect of these molecules towards their bacterial target. We also present evidence that these N-acylated compounds are highly effective at killing intracellular bacteria, suggesting the suitability of these antibiotics for therapeutic treatment.

Granulomatous hepatitis due to Bartonella henselae infection in an immunocompetent patient

Background

Bartonella henselae (B. henselae) is considered a rare cause of granulomatous hepatitis. Due to the fastidious growth characteristics of the bacteria, the limited sensitivity of histopathological stains, and the non-specific histological findings on liver biopsy, the diagnosis of hepatic bartonellosis can be difficult to establish. Furthermore, the optimal treatment of established hepatic bartonellosis remains controversial.

Case presentation

We present a case of hepatic bartonellosis in an immunocompetent woman who presented with right upper quadrant pain and a five cm right hepatic lobe mass on CT scan. The patient underwent a right hepatic lobectomy. Surgical pathology revealed florid necrotizing granulomatous hepatitis, favoring an infectious etiology. Despite extensive histological and serological evaluation a definitive diagnosis was not established initially. Thirteen months after initial presentation, hepatic bartonellosis was diagnosed by PCR studies from surgically excised liver tissue. Interestingly, the hepatic granulomas persisted and Bartonella henselae was isolated from the patient's enriched blood culture after several courses of antibiotic therapy.

Conclusion

The diagnosis of hepatic bartonellosis is exceedingly difficult to establish and requires a high degree of clinical suspicion. Recently developed, PCR-based approaches may be required in select patients to make the diagnosis. The optimal antimicrobial therapy for hepatic bartonellosis has not been established, and close follow-up is needed to ensure successful eradication of the infection.

Bartonella infection: treatment and drug resistance

Bartonella species, which belong to the α-2 subgroup of Proteobacteria, are fastidious Gram-negative bacteria that are highly adapted to their mammalian host reservoirs. Bartonella species are responsible for different clinical conditions affecting humans, including Carrion's disease, cat scratch disease, trench fever, bacillary angiomatosis, endocarditis and peliosis hepatis. While some of these diseases can resolve spontaneously without treatment, in other cases, the disease is fatal without antibiotic treatment. In this article, we discuss the antibiotic susceptibility patterns of Bartonella species, detected using several methods. We also provide an overview of Bartonella infection in humans and animals and discuss the antibiotic treatment recommendations for the different infections, treatment failure and the molecular mechanism of antibiotic resistance in these bacteria.

Refractory Bartonella quintana bacillary angiomatosis following chemotherapy for chronic lymphocytic leukaemia

Bacillary angiomatosis is a well-recognized infection with cutaneous and systemic manifestations caused by Bartonella henselae or Bartonella quintana and occurs in immunocompromised patients. We report a case of B. quintana bacillary angiomatosis following fludarabine-based chemotherapy for chronic lymphocytic leukaemia that was refractory to standard treatment and was complicated by lymphadenopathy and osteomyelitis.

Antimicrobial susceptibility by Etest of Bartonella henselae isolated from cats and human in Japan

Bartonella henselae, a small fastidious Gram-negative bacillus, is the causative agent of cat-scratch disease (CSD). Because of difficulty in isolating the organism, there has been no report on its antibiotic susceptibility in Japan. We determined the minimal inhibitory concentrations (MICs) of eight antimicrobial agents against 32 isolates of B. henselae (31 from cats and one from a human in Japan) by the Etest method. MICs of all 32 isolates were <0.016 μg/ml for minocycline and ranged from ≤0.016 to 0.064 μg/ml for erythromycin, clarithromycin, azithromycin, ceftriaxone, and amoxicillin. MICs ranges of ciprofloxacin and gentamicin were from 0.064 to 0.25 μg/ml and from 0.5 to 3 μg/ml, respectively. All isolated strains showed high susceptibility to minocycline and macrolides antibiotics, which are currently used in the primary treatment of CSD in Japan. Although in vitro result of B. henselae susceptibility testing may not necessarily correlate with clinical response, these data are relevant in the choice of drugs for CSD treatment.

[Infective endocarditis due to Bartonella henselae following a rupture of a cerebral aneurysm]

We report a case of severe aortic bicuspid valve endocarditis, revealed by global cardiac failure without fever, in a 38-year-old man who had developed cerebral mycotic aneurysms nine months earlier. PCR analysis of the excised aortic valve and serological tests (even 9 months earlier) were positive for Bartonella henselae. A combination of intravenous then oral doxycyclin at 200mg/day and intravenous gentamycin at 90mg/day was given for 6 and 2 weeks respectively. The evolution was favorable on follow-up, 12 months after completion of the therapy. Only 49 cases of B. henselae endocarditis have been reported to date, none with associated mycotic aneurysm but most often located on the bicuspid aortic valve, and usually with severe valvular damage due to late diagnosis.