The adult microbiome of healthy and otitis patients: Definition of the core healthy and diseased ear microbiomes.

Otitis media (OM) and externa (OE) are painful, recurrent ear conditions. As most otitis publications focus on the bacterial content of childhood ears, there remains a dearth of information regarding the adult ear microbiome including both bacteria and fungi. This study compares the outer ear microbiome of healthy adults to adults affected by OE and OM using both intergenic-transcribed-spacer (ITS) and 16S-rDNA sequencing. The adult ear core microbiome consists of the prokaryote Cutibacterium acnes and the eukaryotic Malassezia arunalokei, M. globosa, and M. restricta. The healthy ear mycobiome is dominated by Malassezia and can be divided into two groups, one dominated by M. arunalokei, the other by M. restricta. Microbiome diversity and biomass varied significantly between healthy and diseased ears, and analyses reveal the presence of a potential mutualistic, protective effect of Malassezia species and C. acnes. The healthy ear core microbiome includes the bacteria Staphylococcus capitis and S. capitis/caprae, while the diseased ear core is composed of known bacterial and fungal pathogens including Aspergillus sp., Candida sp., Pseudomonas aeruginosa, S. aureus, and Corynebacterium jeikeium. The data presented highlight the need for early detection of the cause of otitis to direct more appropriate, efficient treatments. This will improve patient outcomes and promote improved antimicrobial stewardship.

Defining the microbiome of the head and neck: A contemporary review.

OBJECTIVE: The purpose of this paper is to define the microbiome of the head and neck by characterizing and distinguishing the commensal bacteria from pathogenic species. STUDY DESIGN: Literature review. METHODS: Pubmed and Google scholar databases were queried for relevant articles. Keywords such as "middle ear microbiome", "outer ear microbiome", "sinonasal microbiome", "tonsil microbiome", and "laryngeal microbiome" were utilized separately to identify articles pertaining to each topic of study. All applicable abstracts were chosen for initial review and relevant abstracts were then selected for review of the full texts. Articles that did not study the human microbiome, those not written primarily in English, those that were not readily available for full review, and case reports were excluded from the study. RESULTS: Limited studies that investigate the microbial environments of isolated anatomic subsites in the head and neck exist, however the comprehensive microbiome of the head and neck has yet to be completely defined. Based on this review, various studies of the ears, larynx, tonsils and sinus microbiomes exist and yield valuable information, however they are limited in scope and anatomic subsite. In this literature review, these studies are compiled in order to create a comprehensive text inclusive of the known microbial elements of the major anatomic subsites of the head and neck, namely the tonsils, larynx, sinus, outer ear and middle ear. CONCLUSIONS: The significance of the human microbiome in identifying and preventing disease has been established in various physiologic systems, however there is limited research on the microbiome of the head and neck. Understanding the microbiome of the head and neck can help differentiate disease-prone patients from normal patients and guide treatment regimens and antibiotic usage, to aid in resistance control and limit adverse effects of antibiotic overuse. Understanding the elements that lead to dysbiosis can help treat and even prevent common conditions as tonsillitis and rhinosinusitis. In this review, we provide a comprehensive review to serve as an initial background for future studies to define the head and neck microbiome distinguished by all relevant subsites.

Upper Respiratory Tract Microbiome of Australian Aboriginal and Torres Strait Islander Children in Ear and Nose Health and Disease.

The objective of this study was to examine the nasal microbiota in relation to otitis media (OM) status and nose health in Indigenous Australian children. Children 2 to 7 years of age were recruited from two northern Australian (Queensland) communities. Clinical histories were obtained through parent interviews and reviews of the medical records. Nasal cavity swab samples were obtained, and the children's ears, nose, and throat were examined. DNA was extracted and analyzed by 16S rRNA amplicon next-generation sequencing of the V3/V4 region, in combination with previously generated culture data. A total of 103 children were recruited (mean age, 4.7 years); 17 (16.8%) were healthy, i.e., normal examination results and no history of OM. The nasal microbiota differed significantly in relation to OM status and nose health. Children with historical OM had greater relative abundance of Moraxella, compared to healthy children, despite both having healthy ears at the time of swabbing. Children with healthy noses had greater relative abundance of Staphylococcus aureus, compared to those with rhinorrhea. Dolosigranulum was correlated with Corynebacterium in healthy children. Haemophilus and Streptococcus were correlated across phenotypes. Ornithobacterium was absent or was present with low relative abundance in healthy children and clustered around otopathogens. It correlated with Helcococcus and Dichelobacter. Dolosigranulum and Corynebacterium form a synergism that promotes upper respiratory tract (URT)/ear health in Indigenous Australian children. Ornithobacterium likely represents "Candidatus Ornithobacterium hominis" and in this population is correlated with a novel bacterium that appears to be related to poor URT/ear health. IMPORTANCE Recurring and chronic infections of the ear (OM) are disproportionately prevalent in disadvantaged communities across the globe and, in particular, within Indigenous communities. Despite numerous intervention strategies, OM persists as a major health issue and is the leading cause of preventable hearing loss. In disadvantaged communities, this hearing loss is associated with negative educational and social development outcomes, and consequently, poorer employment prospects and increased contact with the justice system in adulthood. Thus, a better understanding of the microbial ecology is needed in order to identify new targets to treat, as well as to prevent the infections. This study used a powerful combination of 16S rRNA gene sequencing and extended culturomics to show that Dolosigranulum pigrum, a bacterium previously identified as a candidate protective species, may require cocolonization with Corynebacterium pseudodiphtheriticum in order to prevent OM. Additionally, emerging and potentially novel pathogens and bacteria were identified.

Intravital Imaging of Candida albicans Identifies Differential In Vitro and In Vivo Filamentation Phenotypes for Transcription Factor Deletion Mutants.

Candida albicans is an important cause of human fungal infections. A widely studied virulence trait of C. albicans is its ability to undergo filamentation to hyphae and pseudohyphae. Although yeast, pseudohyphae, and hyphae are present in pathological samples of infected mammalian tissue, it has been challenging to characterize the role of regulatory networks and specific genes during in vivo filamentation. In addition, the phenotypic heterogeneity of C. albicans clinical isolates is becoming increasingly recognized, while correlating this heterogeneity with pathogenesis remains an important goal. Here, we describe the use of an intravital imaging approach to characterize C. albicans filamentation in a mammalian model of infection by taking advantage of the translucence of mouse pinna (ears). Using this model, we have found that the in vitro and in vivo filamentation phenotypes of different C. albicans isolates can vary significantly, particularly when in vivo filamentation is compared to solid agar-based assays. We also show that the well-characterized transcriptional regulators Efg1 and Brg1 appear to play important roles both in vivo and in vitro. In contrast, Ume6 is much more important in vitro than in vivo. Finally, strains that are dependent on Bcr1 for in vitro filamentation are able to form filaments in vivo in its absence. This intravital imaging approach provides a new approach to the systematic characterization of this important virulence trait during mammalian infection. Our initial studies provide support for the notion that the regulation and initiation of C. albicans filamentation in vivo is distinct from in vitro induction. IMPORTANCE Candida albicans is one of the most common causes of fungal infections in humans. C. albicans undergoes a transition from a round yeast form to a filamentous form during infection, which is critical for its ability to cause disease. Although this transition has been studied in the laboratory for years, methods to do so in an animal model of infection have been limited. We have developed a microscopy method to visualize fluorescently labeled C. albicans undergoing this transition in the subcutaneous tissue of mice. Our studies indicate that the regulation of C. albicans filamentation during infection is distinct from that observed in laboratory conditions.

Electricity-producing Staphylococcus epidermidis counteracts Cutibacterium acnes.

Staphylococcus epidermidis (S. epidermidis) ATCC 12228 was incubated with 2% polyethylene glycol (PEG)-8 Laurate to yield electricity which was measured by a voltage difference between electrodes. Production of electron was validated by a Ferrozine assay. The anti-Cutibacterium acnes (C. acnes) activity of electrogenic S. epidermidis was assessed in vitro and in vivo. The voltage change (~ 4.4 mV) reached a peak 60 min after pipetting S. epidermidis plus 2% PEG-8 Laurate onto anodes. The electricity produced by S. epidermidis caused significant growth attenuation and cell lysis of C. acnes. Intradermal injection of C. acnes and S. epidermidis plus PEG-8 Laurate into the mouse ear considerably suppressed the growth of C. acnes. This suppressive effect was noticeably reversed when cyclophilin A of S. epidermidis was inhibited, indicating the essential role of cyclophilin A in electricity production of S. epidermidis against C. acnes. In summary, we demonstrate for the first time that skin S. epidermidis, in the presence of PEG-8 Laurate, can mediate cyclophilin A to elicit an electrical current that has anti-C. acnes effects. Electricity generated by S. epidermidis may confer immediate innate immunity in acne lesions to rein in the overgrowth of C. acnes at the onset of acne vulgaris.

Recurrent polyp formation with Candida tropicalis infection and otitis in a dog.

To describe a case of a recurrent Candida tropicalis otitis externa, media and interna in a dog with an ear polyp. A 9-year-old Irish Setter was presented with 2 episodes of otitis sinistra, left-sided vestibular syndrome and Horner syndrome 7 months apart. At the first episode a benign ear polyp was extracted and Candida tropicalis cultured from the left middle ear. The neurological signs disappeared within 7 days, the Candida infection was more difficult to treat. Seven months later, a polyp was found in the ear again and cytology was consistent with Candida tropicalis. A unilateral left total ear canal ablation with lateral bulla osteotomy was performed and a middle ear culture confirmed Candida tropicalis. Treatment led to resolution of clinical signs. Candida tropicalis, an emerging pathogen, should be considered in cases of recurrent yeast otitis and may be difficult to treat.

The canine skin and ear microbiome: A comprehensive survey of pathogens implicated in canine skin and ear infections using a novel next-generation-sequencing-based assay.

This study analyzed the complex bacterial and fungal microbiota of healthy and clinically affected canine ear and skin samples. A total of 589 canine samples were included: 257 ear swab samples (128 healthy vs. 129 clinically affected) and 332 skin swab samples (172 healthy vs. 160 clinically affected) were analyzed using next-generation sequencing (NGS) to determine both relative and absolute abundances of bacteria and fungi present in the samples. This study highlighted the canine microbiota of clinically affected cases was characterized by an overall loss of microbial diversity, high microbial biomass, with overgrowth of certain members of the microbiota. The observed phenotype of these samples was best described by the combination of both relative and absolute microbial abundances. Compared to healthy samples, 78.3% of the clinically affected ear samples had microbial overgrowth; 69.8% bacterial overgrowth, 16.3% fungal overgrowth, and 7.0% had both bacterial and fungal overgrowth. The most important microbial taxa enriched in clinically affected ears were Malassezia pachydermatis, Staphylococcus pseudintermedius, Staphylococcus schleiferi, and a few anaerobic bacteria such as Finegoldia magna, Peptostreptococcus canis, and Porphyromonas cangingivalis. The anaerobic microbes identified here were previously not commonly recognized as pathogens in canine ear infections. Similar observations were found for skin samples, but yeasts and anaerobes were less abundant when compared to clinically affected cases. Results highlighted herein, signify the potential of NGS-based methods for the accurate quantification and identification of bacterial and fungal populations in diagnosing canine skin and ear infections, and highlight the limitations of traditional culture-based testing.

Proportion of Streptococcus agalactiae vertical transmission and associated risk factors among Ethiopian mother-newborn dyads, Northwest Ethiopia.

Group B Streptococcus (GBS) vertical transmission causes fetal and neonatal colonization and diseases. However, there is scarcity of data in low-income countries including Ethiopia. We conducted a cross-sectional study on 98 GBS positive mothers, and their newborns to find proportion of vertical transmission. GBS was identified from swabs by using recommended methods and vertical transmission at birth was confirmed by the culture of body surface swabs of newborns within 30 minutes following birth. GBS positivity among swabbed specimens collected for other purposes was 160/1540 (10.4%); 98 were from 385 recto-vaginal swabs of pregnant women, and 62 were from 1,155 swabs of the 385 births. Of the 98 GBS positive cases, 62 newborns were GBS colonized with vertical transmission proportion of 63.3%(95% CI: 54.1-72.4%). We identified that the proportion of vertical transmission in this study was within the range of other many global studies, but higher than recently published data in Ethiopia. Maternal educational level, employment and lower ANC visit were significantly associated risk factors to GBS vertical transmission. Efforts need to be made to screen pregnant women during antenatal care and to provide IAP to GBS positive cases to reduce mother to newborn vertical transmission.

A mouse ear skin model to study the dynamics of innate immune responses against Staphylococcus aureus biofilms.

BACKGROUND: Staphylococcus aureus is a human pathogen that is a common cause of nosocomial infections and infections on indwelling medical devices, mainly due to its ability to shift between the planktonic and the biofilm/sessile lifestyle. Biofilm infections present a serious problem in human medicine as they often lead to bacterial persistence and thus to chronic infections. The immune responses elicited by biofilms have been described as specific and ineffective. In the few experiments performed in vivo, the importance of neutrophils and macrophages as a first line of defence against biofilm infections was clearly established. However, the bilateral interactions between biofilms and myeloid cells remain poorly studied and analysis of the dynamic processes at the cellular level in tissues inoculated with biofilm bacteria is still an unexplored field. It is urgent, therefore, to develop biologically sound experimental approaches in vivo designed to extract specific immune signatures from the planktonic and biofilm forms of bacteria. RESULTS: We propose an in vivo transgenic mouse model, used in conjunction with intravital confocal microscopy to study the dynamics of host inflammatory responses to bacteria. Culture conditions were created to prepare calibrated inocula of fluorescent planktonic and biofilm forms of bacteria. A confocal imaging acquisition and analysis protocol was then drawn up to study the recruitment of innate immune cells in the skin of LysM-EGFP transgenic mice. Using the mouse ear pinna model, we showed that inflammatory responses to S. aureus can be quantified over time and that the dynamics of innate immune cells after injection of either the planktonic or biofilm form can be characterized. First results showed that the ability of phagocytic cells to infiltrate the injection site and their motility is not the same in planktonic and biofilm forms of bacteria despite the cells being considerably recruited in both cases. CONCLUSION: We developed a mouse model of infection to compare the dynamics of the inflammatory responses to planktonic and biofilm bacteria at the tissue and cellular levels. The mouse ear pinna model is a powerful imaging system to analyse the mechanisms of biofilm tolerance to immune attacks.

Genotypic differences in CC224, CC363, CC449 and CC446 of Moraxella catarrhalis isolates based on whole genome SNP, MLST and PFGE typing.

Understanding the evolutionary path of M. catarrhalis from macrolide-susceptible to macrolide-resistant organism, is important for hindering macrolide resistance from propagation. Multilocus sequence typing (MLST), pulsed-field gel electrophoresis (PFGE) and whole genome SNP typing (WGST), as useful and practical typing tools, have both advantages and disadvantages. We studied the utility of these 3 typing methods, including the level of agreement, consistency and drawbacks, in characterizing M. catarrhalis clones and clonal complexes. We focused on four clonal complexes [CC224, CC363, CC449 (CCN10) and CC446 (CCN08)] and found that PFGE and WGST had a high level of agreement and a proper consistency of the same clone or very closely related clones, while MLST is less discriminatory for different clones. Furthermore, we also established an evolutionary distance cut-off value for "The same clone". Moreover, we detected macrolide-resistant M. catarrhalis in CC224, which had previously been considered as a macrolide-susceptible clonal complex. A higher number of isolates belonged to ST215 compared to ST446, implying that ST215 is more likely to be the primary founder. Our study also demonstrated that all the four clonal complexes belong to the M. catarrhalis lineage 1, which is considered to be related to increased virulence potential and serum resistance. We also observed that copB II was highly related to CC449 and LOS type B was mainly confined in CC224. In conclusion, these findings provide further insight into the evolutionary characteristics of M. catarrhalis.

Emendation of the Genus Auritidibacter Yassin et al. 2011 and Auritidibacter ignavus Yassin et al. 2011 based on features observed from Canadian and Swiss clinical isolates and whole-genome sequencing analysis.

Auritidibacter ignavus is a Gram-stain-positive bacillus derived from otorrhea. Four strains derived from ear discharges in Canada and Switzerland, with features consistent with but distinguishable from Auritidibacter ignavus IMMIB L-1656T (accession number FN554542) by 16S rRNA gene sequencing (97.5 % similarity), were thought to represent a novel species of the genus Auritidibacter. Auritidibacter ignavus DSM 45359T (=IMMIB L-1656T) was acquired to compare with Canadian and Swiss strains by whole-genome sequencing (WGS). Unexpectedly, those isolates were observed to be consistent with A. ignavus DSM 45359T by WGS (ANIb scores >98 %), MALDI-TOF (Bruker), cellular fatty acid analysis and biochemically (some differences were observed). A nearly full 16S rRNA gene sequence could not be readily prepared from A. ignavus DSM 45359T, even after multiple attempts. A 16S rRNA gene chimeric consensus sequence created from the genome assembly of A. ignavus DSM 45359T had only 97.5 % similarity to that of A. ignavus IMMIB L-1656T, implying that 16S rRNA sequence accession number FN554542 could not be replicated. We concluded that our isolates of members of the genus Auritidibacter were consistent with A. ignavus DSM 45359T, did not represent a novel species, and that the sequence corresponding to FN554542 was not reproducible. By WGS, A. ignavus DSM 45359T had genome of 2.53×106 bp with a DNA G+C content of 59.34%, while genomes of Canadian and Swiss isolates ranged from 2.47 to 2.59×106 bp with DNA G+C contents of 59.3-59.52 %. A. ignavus NML 100628 (=NCTC 14178=LMG 30897) did not demonstrate a rodcoccus cycle. Emendation of Auritidibacter ignavus was proposed based on these results.

Candida auris colonization or infection of the ear: A single-center study in South Korea from 2016 to 2018.

Candida auris was first identified in Japan from specimens obtained from the ear, but most reports since have reported invasive infections or non-ear based cases. We reviewed all the microbiology records from a single center in South Korea from February 2016 to July 2018. One hundred eleven isolates were positive for C. auris from 79 patients. All 79 patients positive for C. auris had positive ear discharge samples. All but one of the patients with C. auris had been to the otorhinolaryngology clinic. Symptom-driven ear culture was done for all but one patient, whose culture was performed for surveillance. Ear discharges were mostly purulent (60%) or serous (34%). We performed the environmental cultures at the otorhinolaryngology outpatient clinic to evaluate the environmental contamination of C. auris, but C. auris was not isolated from medical equipment and environmental surfaces.

Malassezia japonica is part of the cutaneous microbiome of free-ranging golden-headed lion tamarins (Leontopithecus chrysomelas - Kuhl, 1820).

We investigated Malassezia spp. in external ear canal and haircoat of free-ranging golden-headed lion tamarins (Leontopithecus chrysomelas). A total of 199 animals were restrained, and 597 clinical samples were collected. After the amplification of the 26S ribosomal gene by polymerase chain reaction (PCR), the RFLP technique was performed. Two additional PCR protocols were performed in 10 randomly selected strains. Malassezia sp. was isolated in 38.2% (76/199) of the animals and 14.6% (87/597) of the samples; all strains were lipodependent. The 10 sequenced strains showed a high identity with Malassezia japonica, species described in man, but not in animals, so far.

[The role of the microbiome in otorhinolaryngology]. / A mikrobiom szerepe a fül-orr-gégészetben.

Our health is highly determined by the diverse microbial community living within our body and upon our skin. Balance among the members of the commensal microbiota is essential for the preservation of health. New generation sequencing is a rapid, sensitive method for determining the whole microbiome without prior hypothesis and also gives information on the resistance and virulence status. Application of this method can help to identify the pathogens contributing to different diseases, and also the protective bacteria inhibiting their growth. Detecting the changes of the microbiome helps to identify new therapeutic targets and establish targeted antibiotic therapy. Broad-spectrum antibiotics also act against the beneficial members of the microbial flora, which may lead to the development of recurrent or chronic disease. Ear, nose and throat infections are the most common infective diseases in humans and the leading cause for antibiotic prescription worldwide. In recent years, many studies using molecular biology methods were performed examining the microbiome of healthy humans and in otorhinolaryngologic diseases. In the present work, the authors review the changes of the microbiological communities in the healthy state and in various pathologic states in the anatomic regions of the ear, nose and throat. Orv Hetil. 2019; 160(39): 1533-1541.

An Intradermal Model for Yersinia pestis Inoculation.

The dermis and the subcutaneous space vary in many fundamental characteristics, which include composition of lymphatic vessels, density of blood vasculature, and cells of the immune response. Traditional approaches employ the subcutaneous space as the preferred layer of the skin to inoculate Yersinia pestis for bubonic plague studies. Because fleas transmit Y. pestis in nature, and because these insects target the dermal layer of the skin, an intradermal model of infection is more biologically relevant than a subcutaneous model. Among many features, the use of an intradermal model results in robust and reproducible colonization of lymph nodes, blood, and deeper tissues. Remarkably, intradermal inoculation in the murine ear pinna also allows for the study of cutaneous infection without severely disrupting the architecture and physiology of the skin.

Capacity To Utilize Raffinose Dictates Pneumococcal Disease Phenotype.

Streptococcus pneumoniae is commonly carried asymptomatically in the human nasopharynx, but it also causes serious and invasive diseases such as pneumonia, bacteremia, and meningitis, as well as less serious but highly prevalent infections such as otitis media. We have previously shown that closely related pneumococci (of the same capsular serotype and multilocus sequence type [ST]) can display distinct pathogenic profiles in mice that correlate with clinical isolation site (e.g., blood versus ear), suggesting stable niche adaptation within a clonal lineage. This has provided an opportunity to identify determinants of disease tropism. Genomic analysis identified 17 and 27 single nucleotide polymorphisms (SNPs) or insertions/deletions in protein coding sequences between blood and ear isolates of serotype 14 ST15 and serotype 3 ST180, respectively. SNPs in raffinose uptake and utilization genes (rafR or rafK) were detected in both serotypes/lineages. Ear isolates were consistently defective in growth in media containing raffinose as the sole carbon source, as well as in expression of raffinose pathway genes aga, rafG, and rafK, relative to their serotype/ST-matched blood isolates. Similar differences were also seen between serotype 23F ST81 blood and ear isolates. Analysis of rafR allelic exchange mutants of the serotype 14 ST15 blood and ear isolates demonstrated that the SNP in rafR was entirely responsible for their distinct in vitro phenotypes and was also the determinant of differential tropism for the lungs versus ear and brain in a mouse intranasal challenge model. These data suggest that the ability of pneumococci to utilize raffinose determines the nature of disease.IMPORTANCES. pneumoniae is a component of the commensal nasopharyngeal microflora of humans, but from this reservoir, it can progress to localized or invasive disease with a frequency that translates into massive global morbidity and mortality. However, the factors that govern the switch from commensal to pathogen, as well as those that determine disease tropism, are poorly understood. Here we show that capacity to utilize raffinose can determine the nature of the disease caused by a given pneumococcal strain. Moreover, our findings provide an interesting example of convergent evolution, whereby pneumococci belonging to two unrelated serotypes/lineages exhibit SNPs in separate genes affecting raffinose uptake and utilization that correlate with distinct pathogenic profiles in vivo This further underscores the critical role of differential carbohydrate metabolism in the pathogenesis of localized versus invasive pneumococcal disease.

Cross-contamination of bacteria-colonized pierced earring holes and fingers in nurses is a potential source of health care-associated infections.

BACKGROUND: In recent years, the wearing of pierced earrings for personal adornment has increased among health care workers in Japan. However, the transmission dynamics between bacteria in pierced earring holes and fingers has not been clearly shown. METHODS: Earlobes and fingers of 200 nurses (128 nurses with pierced earlobes and 72 nurses with unpierced earlobes) working at a university hospital were sampled to determine whether cross-transmission of bacteria-colonized pierced earring holes and fingers in nurse is possible. RESULTS: Of 128 nurses who had pierced earring holes, Staphylococcus aureus was recovered from earlobes of 24 nurses (18.8%) compared with 7 of 72 nurses without pierced earring holes (9.7%) (P = .09). Of those 15 nurses yielding S aureus from both earlobes and fingers, 12 were from nurses who had pierced earring holes compared with 3 nurses without pierced earring holes. Excluding 1 nurse, antimicrobial susceptibility patterns and genotypes of S aureus from both earlobe and fingers of each nurse were identical. CONCLUSION: Pierced earlobes can be a source of health care-associated infection via cross-transmission of bacteria from earlobe holes to fingers.

Dual-Modal In Vivo Fluorescence/Photoacoustic Microscopy Imaging of Inflammation Induced by GFP-Expressing Bacteria.

In this study, dual-modal fluorescence and photoacoustic microscopy was performed for noninvasive and functional in vivo imaging of inflammation induced by green fluorescent protein (GFP) transfected bacteria in mice ear. Our imaging results demonstrated that the multimodal imaging technique is able to monitor the tissue immunovascular responses to infections with molecular specificity. Our study also indicated that the combination of photoacoustic and fluorescence microscopy imaging can simultaneously track the biochemical changes including the bacterial distribution and morphological change of blood vessels in the biological tissues with high resolution and enhanced sensitivity. Consequently, the developed method paves a new avenue for improving the understanding of the pathology mechanism of inflammation.