Identification of bacteria from clinical samples using Bartonella alpha-Proteobacteria growth medium

Blood Supplementation Enhances Bartonella henselae Growth and Molecular Detection of Bacterial DNA in Liquid Culture

Bacteria of the genus Bartonella, a member of the Alphaproteobacteria, are fastidious, Gram-negative, aerobic bacilli that comprise numerous species, subspecies, and genotypes. Bartonella henselae, with a worldwide distribution, infects cats, dogs, horses, humans, and other mammals. Diagnostically, direct detection of Bartonella henselae in patient blood specimens by culture or molecular methods is required to confirm infection with this bacterium. Enrichment blood culture combined with quantitative PCR (qPCR) or ddPCR enhances the sensitivity of direct detection. The addition of sheep blood to liquid culture media increased the Bartonella henselae DNA concentration compared to controls, additionally improving PCR direct detection sensitivity. IMPORTANCE This study aims to improve diagnostic detection of Bartonella henselae. Patient samples are combined with enriched bacterial cultures aimed at growing Bartonella henselae for the best possible chance at detection. However, current Bartonella growth methods could be improved. The DNA extraction method used by most laboratories should also be optimized. Sheep blood was added to increase the growth of Bartonella henselae and multiple DNA extraction methods were to be compared to each other.

Genetic diversity and Multilocus Sequence Typing Analysis of Bartonella henselae in domestic cats from Southeastern Brazil

Bartonella henselae is the causative agent for the infectious disease Cat Scratch Disease (CSD), which can be fatal. Domestic and wild felines are known to be its main mammal reservoirs. The present study aimed to investigate the occurrence and genetic diversity of Bartonella spp. in cats sampled in São Paulo (SP) and Minas Gerais (MG) States, Southeastern Brazil. Based on a quantitative real-time PCR (qPCR) assay, a Bartonella sp. nuoG gene fragment was detected in 39.9% (122/306) of the blood samples (46/151 cats of SP; 76/155 cats of MG). The blood samples were submitted to a pre-enrichment culture technique that allowed the detection of 12 additional positive samples, which showed to be negative in the qPCR using DNA blood samples as templates. Furthermore, five B. henselae isolates were obtained from qPCR-negative samples for both blood and pre-enrichment culture. Seven out of 24 Ctenocephalides felis fleas were positive for Bartonella spp. in the qPCR assay; 4/7 positive fleas were collected from Bartonella-negative cats. Twenty-three rpoB B. henselae cloned sequences were obtained from nine cats' blood samples, showing the occurrence of 13 different genotypes. Median-joining network and SplitsTree distance analysis showed that the obtained sequences represented distinct B. henselae genotypes when compared to those previously deposited in GenBank. Intra-host diversity was found, since different rpoB genotypes of B. henselae were detected in individual single cats. Bartonella henselae isolates showed two allelic profiles (ST37 in cats from MG state and ST9 in SP state) by MLST (Multilocus Sequence Typing) based on sequencing of eight molecular markers. The present study is the first molecular report of Bartonella sp. in cats from Minas Gerais State. In summary, this body of work showed the occurrence of different B. henselae rpoB genotypes at an intra-reservoir host level. Based on qPCR from blood samples and pre-enrichment liquid culture and isolation, occurrence of 33.1% (50/151) and 56.8% (88/155) for Bartonella sp. was found in cats from SP and MG states, respectively. Two different allelic profiles of B. henselae were found in cats from the states of São Paulo (ST9) and Minas Gerais (ST37), suggesting a clonal evolution of Bartonellae in a certain geographical region.

Breitschwerdt E. Suspected Bartonella osteomyelitis in a dog

Bartonella associated osteomyelitis, while described in humans and a cat, has to our knowledge not been described in dogs. Infection with Bartonella spp. should be considered as a potential bacterial cause of osteomyelitis in dogs.

Molecular Detection of Bartonella spp. and Hematological Evaluation in Domestic Cats and Dogs from Bangkok, Thailand

(1) Background: Bartonella spp. are Gram-negative, facultative, intracellular bacteria transmitted by hematophagous insects. Several species cause zoonotic diseases such as cat-scratch disease. Bartonella henselae and Bartonella clarridgeiae are the main species found in Thailand, however, there have been few studies on Bartonella spp. In addition, the hematological evaluation of Bartonella-infected animals is limited in Thailand. The aims of this study were prevalence investigation and hematological evaluation of Bartonella-infected dogs and cats residing in Bangkok, Thailand. (2) Methods: In total, 295 dogs and 513 cats were molecularly evaluated to detect Bartonella spp. using PCR with primers targeting the partial gltA, rpoB, ftsZ, ribC, and groEL genes. In total, 651 domestic animals were evaluated for hematological parameters compared between Bartonella-positive and Bartonella-negative animals. (3) Results: Overall, the prevalence of Bartonella spp. was 1.61% which was found only in free-ranging cats (2.83%). Bartonella henselae and B. clarridgeiae were confirmed from a concatenated phylogenetic tree of partial gltA and ribC genes, with 100% bootstrapping replication. For other housekeeping gene sequences, mixed infection was expected from the amplicons of rpoB, ftsZ, and groEL. Importantly, the mean corpuscular volume (MCV) was significantly increased in Bartonella-positive cats. (4) Conclusions: We suggest that B. henselae and B. clarridgeiae are important species and are still circulating in domestic animals, especially cats. The evaluation of blood parameters, especially a raised MCV, should be of concern in Bartonella infection in asymptomatic cats. Additionally, the knowledge of how to prevent Bartonella-related diseases should be promoted with people in at-risk situations.

Antibiotic resistance genes in the Actinobacteria phylum

The Actinobacteria phylum is one of the oldest bacterial phyla that have a significant role in medicine and biotechnology. There are a lot of genera in this phylum that are causing various types of infections in humans, animals, and plants. As well as antimicrobial agents that are used in medicine for infections treatment or prevention of infections, they have been discovered of various genera in this phylum. To date, resistance to antibiotics is rising in different regions of the world and this is a global health threat. The main purpose of this review is the molecular evolution of antibiotic resistance in the Actinobacteria phylum.

Bartonella henselae infection in diverse clinical conditions in a tertiary care hospital in north India

Background & objectives:

Bartonella henselae causes infections which closely resemble febrile illness and chronic diseases such as tuberculosis and haematological malignancies. There are not many studies on Bartonella infections from India. The present study was undertaken to diagnose B. henselae infection in diverse clinical conditions in a tertiary care hospital in north India.

Methods:

A total of 145 patients including those with fever and lymphadenopathy, infective endocarditis and neuroretinitis were enrolled in the study. Whole blood, serum and lymph node aspirate and valvular vegetations if available, were obtained. Samples were plated on chocolate agar and brain-heart infusion agar containing five per cent fresh rabbit blood and were incubated at 35°C for at least four weeks in five per cent CO₂ with high humidity. Immunofluorescent antibody assay (IFA) was done for the detection of IgM antibodies in the serum using a commercial kit. Whole blood was used to perform polymerase chain reaction (PCR) for the citrate synthase gene (gltA).

Results:

IFA was positive in 11 of 140 (7.85%) patients and PCR was positive in 3 of 140 (2.14%) patients. Culture was negative in all the cases. A higher incidence of Bartonella infection was seen in patients with fever and lymphadenopathy (n=30), seven of whom were children. In ophthalmological conditions, four cases were IFA positive.

Interpretation & conclusions:

The present study shows that the threat of Bartonella infection is a reality in India. It is also an important treatable cause of fever and lymphadenopathy in children. Serology and PCR are useful tests for its diagnosis. Clinicians should consider Bartonella infection in the differential diagnosis of febrile illnesses and chronic diseases.

Combining amplicon sequencing and metabolomics in cirrhotic patients highlights distinctive microbiota features involved in bacterial translocation, systemic inflammation and hepatic encephalopathy

In liver cirrhosis (LC), impaired intestinal functions lead to dysbiosis and possible bacterial translocation (BT). Bacteria or their byproducts within the bloodstream can thus play a role in systemic inflammation and hepatic encephalopathy (HE). We combined 16S sequencing, NMR metabolomics and network analysis to describe the interrelationships of members of the microbiota in LC biopsies, faeces, peripheral/portal blood and faecal metabolites with clinical parameters. LC faeces and biopsies showed marked dysbiosis with a heightened proportion of Enterobacteriaceae. Our approach showed impaired faecal bacterial metabolism of short-chain fatty acids (SCFAs) and carbon/methane sources in LC, along with an enhanced stress-related response. Sixteen species, mainly belonging to the Proteobacteria phylum, were shared between LC peripheral and portal blood and were functionally linked to iron metabolism. Faecal Enterobacteriaceae and trimethylamine were positively correlated with blood proinflammatory cytokines, while Ruminococcaceae and SCFAs played a protective role. Within the peripheral blood and faeces, certain species (Stenotrophomonas pavanii, Methylobacterium extorquens) and metabolites (methanol, threonine) were positively related to HE. Cirrhotic patients thus harbour a 'functional dysbiosis' in the faeces and peripheral/portal blood, with specific keystone species and metabolites related to clinical markers of systemic inflammation and HE.

Halophilic & halotolerant prokaryotes in humans

Halophilic prokaryotes are described as microorganisms living in hypersaline environments. Here, we list the halotolerant and halophilic bacteria which have been isolated in humans. Of the 52 halophilic prokaryotes, 32 (61.54%) were moderately halophilic, 17 (32.69%) were slightly halophilic and three (5.76%) were extremely halophilic prokaryotes. At the phylum level, 29 (54.72%) belong to Firmicutes, 15 (28.84%) to Proteobacteria, four (7.69%) to Actinobacteria, three (5.78%) to Euryarchaeota and one (1.92%) belongs to Bacteroidetes. Halophilic prokaryotes are rarely pathogenic: of these 52 halophilic prokaryotes only two (3.92%) species were classified in Risk Group 2 (Vibrio cholerae, Vibrio parahaemolyticus) and one (1.96%), species in Risk Group 3 (Bacillus anthracis).

Bartonellosis, One Health and all creatures great and small

BACKGROUND

Bartonellosis is a zoonotic infectious disease of worldwide distribution, caused by an expanding number of recently discovered Bartonella spp.

OBJECTIVES

This review serves as an update on comparative medical aspects of this disease, including the epidemiology, pathogenesis, clinical diagnosis, treatment and challenges.

RESULTS

Of comparative medical importance, Bartonella spp. are transmitted by several arthropod vectors, including fleas, keds, lice, sand flies, ticks and, potentially, mites and spiders. Prior to 1990, there was only one named Bartonella species (B. bacilliformis), whereas there are now over 36, of which 17 have been associated with an expanding spectrum of animal and human diseases. Recent advances in diagnostic techniques have facilitated documentation of chronic bloodstream and dermatological infections with Bartonella spp. in healthy and sick animals, in human blood donors, and in immunocompetent and immunocompromised human patients. The field of Bartonella research remains in its infancy and is rich in questions, for which patient relevant answers are badly needed. Directed Bartonella research could substantially reduce a spectrum of chronic and debilitating animal and human diseases, and thereby reduce suffering throughout the world.

CONCLUSION

A One Health approach to this emerging infectious disease is clearly needed to define disease manifestations, to establish the comparative infectious disease pathogenesis of this stealth pathogen, to validate effective treatment regimens and to prevent zoonotic disease transmission.

Infection with Bartonella henselae in a Danish family

Bartonella species constitute emerging, vector-borne, intravascular pathogens that produce long-lasting bacteremia in reservoir-adapted (natural host or passive carrier of a microorganism) and opportunistic hosts. With the advent of more sensitive and specific diagnostic tests, there is evolving microbiological evidence supporting concurrent infection with one or more Bartonella spp. in more than one family member; however, the mode(s) of transmission to or among family members remains unclear. In this study, we provide molecular microbiological evidence of Bartonella henselae genotype San Antonio 2 (SA2) infection in four of six Danish family members, including a child who died of unknown causes at 14 months of age.

Bartonella spp. bacteremia in blood donors from Campinas, Brazil

Bartonella species are blood-borne, re-emerging organisms, capable of causing prolonged infection with diverse disease manifestations, from asymptomatic bacteremia to chronic debilitating disease and death. This pathogen can survive for over a month in stored blood. However, its prevalence among blood donors is unknown, and screening of blood supplies for this pathogen is not routinely performed. We investigated Bartonella spp. prevalence in 500 blood donors from Campinas, Brazil, based on a cross-sectional design. Blood samples were inoculated into an enrichment liquid growth medium and sub-inoculated onto blood agar. Liquid culture samples and Gram-negative isolates were tested using a genus specific ITS PCR with amplicons sequenced for species identification. Bartonella henselae and Bartonella quintana antibodies were assayed by indirect immunofluorescence. B. henselae was isolated from six donors (1.2%). Sixteen donors (3.2%) were Bartonella-PCR positive after culture in liquid or on solid media, with 15 donors infected with B. henselae and one donor infected with Bartonella clarridgeiae. Antibodies against B. henselae or B. quintana were found in 16% and 32% of 500 blood donors, respectively. Serology was not associated with infection, with only three of 16 Bartonella-infected subjects seropositive for B. henselae or B. quintana. Bartonella DNA was present in the bloodstream of approximately one out of 30 donors from a major blood bank in South America. Negative serology does not rule out Bartonella spp. infection in healthy subjects. Using a combination of liquid and solid cultures, PCR, and DNA sequencing, this study documents for the first time that Bartonella spp. bacteremia occurs in asymptomatic blood donors. Our findings support further evaluation of Bartonella spp. transmission which can occur through blood transfusions.

Bartonella is a genus of small bacteria with worldwide distribution, transmitted by blood-sucking insects, and is capable of causing disease in humans and animals. Some of the clinical presentations of Bartonella spp., such as cat scratch disease, trench fever, and bacillary angiomatosis are well documented; however, novel presentations have been described in the last two decades, ranging from cyclic flu-like syndrome to neurologic disease and life-threatening endocarditis. Asymptomatic human infection is possible and accidental blood transmission has been reported. Bacterium isolation is very difficult because they grow slowly and require special culture media and procedures. Serology testing poorly predicts active Bartonella infection, except in infection of cardiac valves. Therefore, diagnosis is generally challenging. However, when molecular detection techniques are coupled with special culture protocols, enhanced sensitivity and specificity can be achieved. We investigated Bartonella spp. infection prevalence in a large blood donor population and confirmed bacteremia in 1.2% of the subjects. Bloodstream infection was detected with at least three different molecular methods in 3.2% of donors. These results indicate that Bartonella is a genus of importance for transfusion medicine.

Phylogenetic diversity of bacteria isolated from sick dogs using the BAPGM enrichment culture platform

BACKGROUND

Bartonella alpha-Proteobacteria growth medium (BAPGM) enrichment culture has proven useful for documenting Bartonella species infection and has facilitated growth of other fastidious bacteria from human samples.

PURPOSE

To report non-Bartonella bacterial isolates obtained from canine samples cultured using BAPGM enrichment culture.

ANIMALS

Between 2004 and 2008, 695 specimens from 513 dogs were tested by the NCSU-IPRL using the BAPGM enrichment culture. Over the same period of time, blood samples from 270 dogs were cultured by the NCSU-CML using Bactec-Plus Aerobic/F media.

METHODS

BAPGM isolates were characterized using Bartonella genus primers and 16S rDNA primers followed by DNA sequencing. NCSU medical records were retrospectively reviewed. Blood culture results from the NCSU-CML were compared with BAPGM blood culture results.

RESULTS

Seventy-nine non-Bartonella isolates were obtained from 69/513 dogs. The most commonly isolated phylum was Proteobacteria (48.1%) with alpha-Proteobacteria being the most commonly isolated class. Staphylococcus and Sphingomonas were the most commonly isolated genera. The majority of the remaining isolates were bacteria that are rarely isolated from canine samples. Comparison of NCSU-CML and IPRL (BAPGM) blood culture isolates showed alpha-Proteobacteria were isolated more often from BAPGM.

CONCLUSIONS AND CLINICAL IMPORTANCE

Use of insect cell culture enrichment medium, such as BAPGM, appears to enhance the growth of alpha-Proteobacteria, but also results in isolation of non-alpha-Proteobacteria from sick dogs. Future studies are needed to elucidate the utility of BAPGM and other "nonconventional" growth media and methods for isolation of fastidious organisms and to determine if these organisms play a causal role in disease development.

Bartonella henselae infection in a family experiencing neurological and neurocognitive abnormalities after woodlouse hunter spider bites

BACKGROUND

Bartonella species comprise a group of zoonotic pathogens that are usually acquired by vector transmission or by animal bites or scratches.

METHODS

PCR targeting the Bartonella 16S-23S intergenic spacer (ITS) region was used in conjunction with BAPGM (Bartonella alpha Proteobacteria growth medium) enrichment blood culture to determine the infection status of the family members and to amplify DNA from spiders and woodlice. Antibody titers to B. vinsonii subsp. berkhoffii (Bvb) genotypes I-III, B. henselae (Bh) and B. koehlerae (Bk) were determined using an IFA test. Management of the medical problems reported by these patients was provided by their respective physicians.

RESULTS

In this investigation, immediately prior to the onset of symptoms two children in a family experienced puncture-like skin lesions after exposure to and presumptive bites from woodlouse hunter spiders. Shortly thereafter, the mother and both children developed hive-like lesions. Over the ensuing months, the youngest son was diagnosed with Guillain-Barre (GBS) syndrome followed by Chronic Inflammatory Demyelinating Polyradiculoneuropathy (CIDP). The older son developed intermittent disorientation and irritability, and the mother experienced fatigue, headaches, joint pain and memory loss. When tested approximately three years after the woodlouse hunter spider infestation, all three family members were Bartonella henselae seroreactive and B. henselae DNA was amplified and sequenced from blood, serum or Bartonella alpha-proteobacteria (BAPGM) enrichment blood cultures from the mother and oldest son. Also, B. henselae DNA was PCR amplified and sequenced from a woodlouse and from woodlouse hunter spiders collected adjacent to the family's home.

CONCLUSIONS

Although it was not possible to determine whether the family's B. henselae infections were acquired by spider bites or whether the spiders and woodlice were merely accidental hosts, physicians should consider the possibility that B. henselae represents an antecedent infection for GBS, CIDP, and non-specific neurocognitive abnormalities.

Molecular evidence of perinatal transmission of Bartonella vinsonii subsp. berkhoffii and Bartonella henselae to a child

Bartonella vinsonii subsp. berkhoffii, Bartonella henselae, or DNA of both organisms was amplified and sequenced from blood, enrichment blood cultures, or autopsy tissues from four family members. Historical and microbiological results support perinatal transmission of Bartonella species in this family. It is of clinical relevance that Bartonella spp. may adversely influence human reproductive performance.

Molecular documentation of Bartonella infection in dogs in Greece and Italy

This study reports the occurrence of "Bartonella rochalimae" in Europe and the presence of Bartonella vinsonii subsp. berkhoffii genotypes II and III in dogs in southern Italy and provides DNA sequencing evidence of a potentially new Bartonella sp. infecting dogs in Greece and Italy.

Molecular characterization of Bartonella vinsonii subsp. berkhoffii genotype III

The molecular characterization of a Bartonella vinsonii subsp. berkhoffii genotype III strain (NCSU strain 06-CO1) isolated from the blood of a military working dog diagnosed with endocarditis is reported in this study. Several genes were amplified and sequenced for comparative sequence similarity with other strains.