Pyomyositis

Dysphagia and Trismus After Tooth Extraction : Clinical Conondrum

Clinicians should consider disorders of masticatory muscle including lateral pterygoid muscle as a differential diagnosis in patients presenting with dysphagia and trismus after tooth extraction.

Arthritis or an Adjacent Fascial Response? A Case Report of Combined Pyomyositis and Aseptic Arthritis

Pyomyositis, accompanied by aseptic arthritis, has been previously documented in several publications. However, none of the authors in the mentioned case reports offered a pathophysiological explanation for this unusual phenomenon or proposed a treatment protocol. We present a case of a healthy, 70-year-old male who was presented to the emergency department 4 days after tripping over a pile of wooden planks and getting stabbed by a nail to his thigh. The right thigh was swollen. Unproportional pain was produced by a light touch to the thigh. A laboratory test and a CT scan were obtained. The working diagnosis was pyomyositis of the thigh and septic arthritis of the ipsilateral knee. The patient underwent urgent debridement and irrigation of his right thigh. An arthroscopic knee lavage was performed as well. Intraoperative cultures from the thigh revealed the growth of Streptococcus pyogenes and Staphylococcus aureus. Cultures from synovial fluid were sterile; thus, septic arthritis was very unlikely. The source of the knee effusion might have been an aseptic inflammatory response due to the proximity of the thigh infection. Anatomically, the quadriceps muscle inserts on the patella, and its tendon fuses with the knee capsule, creating a direct fascial track from the thigh to the knee. The inflammatory response surrounding the infection may have followed this track, creating a domino effect, affecting adjacent capillaries within the joint capsule, and causing plasma leakage into the synovial space, leading to joint effusion. Our suggested treatment is addressing the primary infection with antibiotics and considering adding anti-inflammatory therapy, given our suspicion that this process has an inflammatory component.

Subscapularis pyomyositis, a rare cause of shoulder pain, in a patient without apparent risk factors: A case report

INTRODUCTION

Pyomyositis, previously tropical, now seen more in temperate zones, particularly in those with HIV, cancer, or diabetes. Even healthy individuals, like athletes, can get it post-exercise or minor injuries. Our patient, in a desert-like area, adds an interesting aspect. Diagnosing is challenging due to deep tissue occurrence and subtle symptoms, leading to delayed detection and higher risks of morbidity.

PRESENTATION OF CASE

A 45-year-old female patient presented with acute left shoulder pain and functional impairment, exacerbated by movement. Clinical examination revealed tenderness upon deep palpation in the left upper posterior thoracic region and restricted range of motion of the affected shoulder.

DISCUSSION

Initial assessments at medical facilities suggested musculoskeletal strain and lower cervical disc prolapse despite normal X-ray results. MRI scans confirmed a developing abscess in the left subscapularis muscle, with intraoperative findings revealing extensive purulent fluid and necrotic tissue. Four surgeries drained the abscess and treated fat necrosis, with tailored antibiotics administered. Subsequent arthroscopy showed fibrous tissue, swelling, and inflammation. At the 3-month check-up, she had fully recovered, experiencing no pain or complications, and had almost regained full range of motion.

CONCLUSION

Shoulder pyomyositis presents diagnostic challenges, causing delayed treatment. This case highlights the importance of considering pyomyositis in severe shoulder pain cases, even without typical risk factors or inconclusive X-rays. Timely recognition, surgical drainage, tailored antibiotics, and physical therapy are crucial. An interdisciplinary approach with orthopaedic surgery, infectious disease specialists, radiology, and physical therapy is vital for comprehensive management, improving outcomes, and reducing complications.

Ultrasound-Guided Conservative Treatment of Pyomyositis Due to Metamizole-Induced Agranulocytosis

Metamizole-induced agranulocytosis is a rare adverse drug reaction with common infectious complications. In this context, pyomyositis of the extremities has not yet been described. Usually, pyomyositis is treated with a combination of antibiotics and surgical intervention. Sonography is described as diagnostic tool for pyomyositis but without defined concrete characteristics for follow-up. This case report describes a widespread pyomyositis due to a metamizole-induced agranulocytosis, which was treated conservatively, using sonography for surveillance.

Pelvic Pyomyositis in Childhood: Clinical and Radiological Findings in a Tertiary Pediatric Center

Pyomyositis (PM) is an infrequent but increasing bacterial infection of the skeletal muscle, with muscles of the pelvis and thigh frequently involved. The diagnosis is often challenging, especially when a deep muscle is affected. We present a single-center pediatric cohort affected by pelvic PM. A retrospective analysis was performed, including children admitted to Meyer Children’s Hospital between 2010 and 2020. Demographic, anamnestic, clinical, laboratory, radiological and management data were collected. Forty-seven patients (range 8 days–16.5 years, 66% males) were selected. Pain (64%), functional limitations (40%) and fever (38%) were the most common presenting symptoms; 11% developed sepsis. The median time to reach the diagnosis was 5 days (IQR 3–9). Staphylococcus aureus was the most common organism (30%), Methicillin-Resistant S aureus (MRSA) in 14%. PM was associated with osteomyelitis (17%), arthritis (19%) or both (45%). The infection was multifocal in 87% of children and determined abscesses in 44% (40% multiple). Pelvic MRI scan, including diffusion-weighted imaging (DWI), always showed abnormalities when performed. Clinical and laboratory findings in pelvic PM are unspecific, especially in infancy. Nevertheless, the infection may be severe, and the suspicion should be higher. MRI is the most useful radiological technique, and DWI sequence could reveal insidious infections.

Severe thoracic pyomyositis in a patient with systemic lupus erythematosus

Pyomyositis may mimic deep vein thrombosis and be misdiagnosed in patients with systemic lupus erythematosus (SLE). We report here on patient with SLE with severe thoracic pyomyositis presented with right upper arm swelling and fever. The patient fully recovered after a serial surgical debridement and antibiotic therapy. Pyomyositis, as well as deep vein thrombosis, should be considered during the differential diagnosis of patients with SLE experiencing fever and unilateral limb oedema. CT and identification of causal pathogens are crucial in the diagnosis of pyomyositis. Early effective antibiotic treatment as well as surgical intervention can together bring about a better outcome.

Point-of-Care Ultrasound Identifies Pyomyositis Secondary to Intramuscular Testosterone Injection: Report of Two Cases

BACKGROUND

Intramuscular (i.m.) injections are a commonly utilized route for medication delivery. Intramuscular-associated soft tissue infections are rare and can include pyomyositis and i.m. abscess. Intramuscular testosterone injections have not been previously implicated in causing pyomyositis. Point-of-care ultrasound is an important bedside tool that can identify pyomyositis and differentiate this infection from more common entities such as cellulitis.

CASE REPORTS

We present two cases of i.m. testosterone-associated pyomyositis. In both cases, the physical examination features were consistent with simple cellulitis. However, point-of-care ultrasound evaluation revealed changes consistent with pyomyositis in each case. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Although uncommon, i.m. injections such as testosterone carry a risk of soft tissue infection. As demonstrated in the above cases, ultrasound can be helpful in making the differentiation between simple cellulitis and pyomyositis. The emergency physician should be cognizant of this complication of therapeutic i.m. injections, as well as the diagnostic efficacy of point-of-care ultrasound in evaluating the extent and location of the soft tissue infection.

Pyomyositis in a Patient Undergoing Chemotherapy for Gastric Cancer: A Case Report and Literature Review

Pyomyositis has recently been recognized as a primary infection of the large skeletal muscles, and it is often accompanied by single or multiple intramuscular abscess formation. Immunocompromised patients, including those with diabetes mellitus, human immunodeficiency virus infection, and cancer, as well as those undergoing chemotherapy, are at a greater risk of developing pyomyositis. A 78-year-old Japanese man with recurrent gastric cancer being treated with chemotherapy presented with sudden-onset pain in his left lower extremity while undergoing a second-line regimen with irinotecan. T2-weighted magnetic resonance imaging (MRI) showed an abnormally high-intensity signal in the left internal and external obturator muscles, a finding consistent with pyomyositis. Following intensive antibiotic treatment, the patient recovered completely and was able to resume chemotherapy with irinotecan. For a patient who developed pyomyositis during chemotherapy for gastric cancer, early diagnosis using MRI followed by administration of timely intensive antibiotic therapy resulted in complete recovery.

Infections of the Peripheral Nervous System

PURPOSE OF REVIEW

This article describes infections that affect the peripheral nervous system, including their clinical features, differential diagnoses, and treatments.

RECENT FINDINGS

Rates of pyomyositis have increased recently in the United States, possibly because of an increase in risk factors such as IV drug use, obesity, and diabetes. Other peripheral nervous system infections, such as diphtheria, have become more common in older patients secondary to a lack of revaccination or waning immunity. Although recommended treatment regimens for most infections remain unchanged over recent years, debate over the ideal dosing and route of administration continues for some infections such as tetanus and leprosy (Hansen disease).

SUMMARY

Infections of the peripheral nervous system are varied in terms of the type of infection, localization, and potential treatment. Nerve conduction studies and EMG can help determine localization, which is key to determining an initial differential diagnosis. It is important to recognize infections quickly to minimize diagnostic delays that could lead to patient morbidity and mortality.

Primary Pyomyositis in Children is No More a Rare Condition: Presentation of 2 Clinical Cases

Primary pyomyositis is a bacterial muscle infection which may lead to abscess formation and severe complications. Although this condition has long been considered "tropical" and rare, mostly affecting immunocompromised patients, cases of pyomyositis have recently raised significantly among healthy children in temperate climates. With these 2 cases we highlight the importance of an early recognition of this condition, allowing an immediate treatment and reducing complications.

Pyomyositis as an Unusual Presentation of Colonic Adenocarcinoma

INTRODUCTION

Pyomyositis has been described in association with hematological malignancies. It is rarely associated with solid cancers, particularly colorectal carcinoma. Colorectal carcinoma can present with local or systemic abscesses by causing perforation of the colonic mucosa, followed by local or hematogenous spread of infection.

CASE PRESENTATION

A 68-year-old male with a history of hypertension and type II diabetes mellitus presented to the emergency department with a 3-day history of left thigh pain. Magnetic resonance imaging of the thigh showed extensive intramuscular edema in the left thigh adductor and psoas muscles consistent with pyomyositis. An urgent debridement and irrigation of the left thigh revealed pan-sensitive Escherichia coli and Streptococcus viridans. Due to the suspicion of a gastrointestinal or genitourinary source of infection, computed tomography of the abdomen and pelvis showed an apple-core lesion along the mid-distal segment of the descending colon. Colonoscopy and biopsy confirmed the diagnosis of colonic adenocarcinoma. The patient underwent a laparoscopic left hemicolectomy with an end colostomy and was started on an adjuvant chemotherapy regimen with no significant side effects.

CONCLUSION

Colorectal carcinoma can be associated with local or systemic abscess formation. When cultures from an abscess show enteric pathogens, it is essential to look to gastrointestinal or genitourinary tracts for the source of infection. Although rare, the diagnosis of pyomyositis should warrant further investigations to unmask the possible underlying cause.

Purulent infectious myositis (formerly tropical pyomyositis)

Purulent infectious myositis (PIM), formerly known as tropical pyomyositis, is a pyogenic infection of skeletal muscles. Staphylococcus aureus, a normal human skin inhabitant, is the main pathogen involved, but multiple other microorganisms have been implicated. Although usually a progressive febrile disease with pain in the affected muscle(s), severe, life-threatening forms have been described, especially in immunosuppressed patients and children. PIM may elude early diagnosis given the lack of overlying skin changes. Hence, high index of suspicion followed by imaging modalities (ultrasonography when superficial and computed tomography or magnetic resonance imaging with contrast when deep) help confirm the diagnosis. Treatment requires combination of percutaneous or open surgical drainage along with antimicrobial therapy guided by culture results. The rising incidence of cases due to methicillin-resistant Staphylococcus aureus (MRSA) strains, makes the inclusion of vancomycin be recommended. This paper reviews PIM highlighting its global distribution, causative agents, predisposing factors, management, and potential complications.

[Infectious myositis]

Infectious myositis is a rare condition that can be caused by bacteria, viruses, parasites or fungi. Muscle pain or weakness are symptoms shared by all type of myositis. Diagnosis is made on clinical presentation: fever and poor general state is found in bacterial myositis, diffuse muscle pain with flu-like symptoms in viral causes, eosinophilia and a tropical travel history can be related to parasitic etiology, and immunocompromising condition suggests fungal infection. Rhabdomyolysis, leukocytosis and elevated C-reactive protein are common. Imaging (computed tomography or magnetic resonance imaging) can be useful to detect which muscle is affected. The causative organism can be identified on blood cultures, skeletal muscle biopsy, serology or any other pathogen specific test. Treatment depends on the causative organism. Open surgical or imaging-guided drainage is usually necessary in bacterial myositis.

Piomiosite do piriforme em um paciente com doença de Kikuchi-Fujimoto—relato de caso e revisão da literatura

Primary pyomyositis is a deep bacterial infection of the skeletal muscle. If left undiagnosed and untreated, the infection spreads, leading to sepsis, septic shock, and even death. The authors report a 23-year-old female presenting with piriformis pyomyositis during a treatment for Kikuchi–Fujimoto disease. Pyomyositis is a rare but potentially severe infection, which can lead to septic shock. The present case shows the need for a high degree of clinical suspicion for patients with compromised immune systems to begin treatment at an early stage. The literature demonstrates that outcomes of the treatment of piriformis pyomyositis are good.

Primary pyomyositis in North India: a clinical, microbiological, and outcome study

BACKGROUND/AIMS

Pyomyositis is an infective condition with primary involvement of the skeletal muscles. There is sparse recent literature on patients with pyomyositis.

METHODS

This study was carried out at emergency services of a tertiary care center located in subtropical area of Indian subcontinent.

RESULTS

Sixty-two patients of primary pyomyositis formed the study cohort. Mean age of occurrence was 29.9 ± 14.8 years. There were 54 men. Twelve patients had underlying medical diseases. Muscle pain was seen in all 62 patients. Forty-eight patients (77.4%) had the fever. Most common site of involvement was thigh muscles (n = 29, 46.8%). Forty-nine patients (79%) presented in the suppurative stage of illness. Patients with comorbidities were older (age: median 36 years [interquartile range (IQR), 25 to 47] vs. 24 years [IQR, 16 to 35], p = 0.024), had higher culture positivity with gram-negative organisms (8/9 [88.89%] vs. 6/29 [20.69%], p = 0.001). Importantly, higher number of these patients received inappropriate antibiotics initially. Patients with positive pus culture result had higher complication rate (32/38 [84.21%] vs. 10/18 [55.56%], p = 0.044). Six patients (9.7%) had in-hospital mortality. Lower first-day serum albumin, initial inappropriate antibiotic therapy, and advanced form of the disease at presentation were associated with increased in-hospital mortality.

CONCLUSIONS

Primary pyomyositis is not an uncommon disease entity. Patients with comorbidities were more likely to receive initial inappropriate antibiotic therapy. Patients with positive pus culture report had the higher rate of complications. Lower first-day serum albumin, initial inappropriate antibiotic therapy and advanced form of the disease at presentation were associated with increased in-hospital mortality.

Concurrent methicillin-resistant Staphylococcus aureus septicemia and pyomyositis in a patient with dengue hemorrhagic fever: a case report

BACKGROUND

Concurrent presence of dengue hemorrhagic fever (DHF), tropical pyomyositis and septicemia due to methicillin-resistant Staphylococcus aureus (MRSA) in a previously healthy person has never been reported. These three conditions even individually are potentially fatal. "Here we describe a case of a patient contracting dengue and developing DHF along with concurrent pyomyositis likely to be due to MRSA, leading to MRSA septicemia with abscesses formed by MRSA".

CASE PRESENTATION

A 44-year old previously healthy Sinhalese man presented on day 3 of the illness with fever, headache, arthralgia and myalgia and watery loose stools. His pulse rate was 76/min, blood pressure was 110/80 mmHg, while cardiovascular, respiratory and abdomen examination findings were unremarkable. The test for the dengue NS1 antigen was positive on the same day. We have diagnosed dengue and started managing him symptomatically as per the current national guidelines. The patient developed DHF with bilateral pleural effusion and ascitis. On the day 5 he developed severe myalgia, tenderness and non pitting edema of lower limbs especially in the thighs. His creatine kinase levels were high and an ultrasound scan confirmed myositis of both thighs. We suspected myositis due to dengue but investigated for possible simultaneous sepsis as well. On day 9 his blood culture became positive for MRSA. Considering the sensitivity of the bacteria intravenous vancomycin and ciprofloxacin was administered for 21 days. He developed a small abscess at the site of the first intravenous access and a large one above the ankle on the left. On day 12 the latter was drained and the pus culture yielded MRSA sensitive to the same antibiotics. The rapid test for dengue IgM was negative initially but later a positive MAC-ELISA test entrenched dengue infection. After improvement he was sent home on day 33 of the illness. He has developed two other abscesses in the proximity of the drained one and they were drained on day 57. The patient recovered.

CONCLUSIONS

When dengue patients develop symptoms and signs of myositis, prompt investigations for pyomyositis and the treatment can save lives.

Ex Vivo Tracer Efficacy in Optical Imaging of Staphylococcus Aureus Nuclease Activity

The key to effective treatment of bacterial infections is a swift and reliable diagnosis. Current clinical standards of bacterial diagnosis are slow and laborious. There are several anatomical imaging modalities that can detect inflammation, but none can distinguish between bacterial and sterile inflammation. Novel tracers such as smart activatable fluorescent probes represent a promising development that allow fast and specific testing without the use of ionizing radiation. Previously, a smart activatable probe was developed that is a substrate for the micrococcal nuclease as produced by Staphylococcus aureus. In the present study, the function of this probe was validated. Practical applicability in terms of sensitivity was assessed by incubation of the probe with 26 clinical S. aureus isolates, and probe specificity was verified by incubation with 30 clinical isolates and laboratory strains of various bacterial pathogens. The results show that the nuclease-specific probe was activated by all tested S. aureus isolates and laboratory strains with a threshold of ~106-107 cells/mL. The probe was also activated by certain opportunistic staphylococci. We therefore propose that the studied nuclease probe represents a significant step forward to address the need for a rapid, practical, and precise method to detect infections caused by S. aureus.

Case 249: Intramuscular Mycetoma

History A 21-year-old man presented with swelling of the medial aspect of the left thigh of 1-month duration. There was no history of fever or penetrating injury in the left thigh. The patient had undergone renal transplantation 7 years earlier and had been taking immunosuppressants since transplantation. He had undergone two surgeries at the same site in the medial aspect of the left thigh in the past 3 years for a similar problem. At physical examination, there was swelling in the medial aspect of the left thigh, with mild tenderness. A surgical scar was noted anterior to the swelling ( Fig 1 ). No redness or discharging sinus was present. Laboratory results were as follows: hemoglobin level, 11.3 g/dL (normal range, 13.8-17.2 g/dL); white blood cell count, 9.7 × 10⁹/L (normal range, [4-11] × 10⁹/L); neutrophil, 75% (normal range, 48%-77%); lymphocyte, 22% (normal range, 10%-24%); eosinophil, 1% (normal range, 0.3%- 7%); monocyte, 1% (normal range, 0.6%-10%); serum creatinine level, 1.3 mg/dL (114.9 μmol/L) (normal range, 0.5-1.6 mg/dL [44.2-141.4 μmol/L]); and serum glucose (random) level, 82 mg/dL (4.5 mmol/L) (normal range, 79-140 mg/dL [4.4-7.8 mmol/L]). Radiography of the left thigh showed soft-tissue swelling in the medial aspect of the left thigh, without underlying bone involvement (not shown). Ultrasonography (US) and magnetic resonance (MR) imaging of the left thigh were performed. [Figure: see text].

Diagnosis and management of skin and soft-tissue infections (SSTI). A literature review and consensus statement: an update

Skin and soft-tissue infections (SSTIs) are among the most common bacterial infections, posing considerable diagnostic and therapeutic challenges. Fourteen members of the Italian Society of Infectious Diseases, after a careful review of the most recent literature using Medline database and their own clinical experience, updated a previous paper published in 2011 by preparing a draught manuscript of the statements. The manuscript was successively reviewed by all members and ultimately re-formulated the present manuscript during a full day consensus meeting. The microbiological and clinical aspects together with diagnostic features were considered for necrotizing and not necrotizing SSTIs in the light of the most recent guidelines and evidences published in the last five years. The antimicrobial therapy was considered as well - both empirical and targeted to methicillin-resistant Staphylococcus aureus and/or other pathogens, also taking into account the epidemiological and bacterial resistance data and the availability of new antibacterial agents.

Pyomyositis is not only a tropical pathology: a case series

Background

Pyomyositis is an acute bacterial infection of skeletal muscle that results in localized abscess formation. This infection was thought to be endemic to tropical countries, and is also known as “tropical pyomyositis”. However, pyomyositis is increasingly recognized in temperate climates and is frequently associated with an immunosuppressive condition, such as human immunodeficiency virus, malignancy, and diabetes mellitus. It is also found in healthy and athletic people after strenuous or vigorous exercise or following localized and possibly unnoticed trauma. It can be primary or secondary to neighboring or remote infection. Primary pyomyositis is a rare condition that can affect children and adolescents. Diagnosis can be delayed because the affected muscle is deeply situated and local signs are not apparent. This delay in diagnosis can result in increased morbidity and a significant mortality rate. The pediatric population, which comprises 35% of the reported pyomyositis cases, is an especially difficult subset of patients to diagnose.

Case presentation

In our series, we describe the cases of four previously healthy Caucasian children who were admitted to our Pediatric Department with different clinical presentations. Pyomyositis in our patients was related to factors affecting the muscle itself, including strenuous exercise and direct muscle trauma. Therapy was started with a cephalosporin antibiotic and teicoplanin was subsequently added. The minimum length of therapy was 3 weeks.

Conclusions

The diagnosis of pyomyositis in our patients, none of whom were immune-compromised, is confirmation that this disease is not an exclusive pathology of tropical countries and demonstrates that there is an increasing prevalence of pyomyositis in temperate climates.

Role of Diffusion Weighted Imaging in Musculoskeletal Infections: Current Perspectives

Accurate diagnosis and prompt therapy of musculoskeletal infections are important prognostic factors. In most cases, clinical history, examination and laboratory findings help one make the diagnosis, and routine magnetic resonance imaging (MRI) is useful to identify the extent of the disease process. However, in many situations, a routine MRI may not be specific enough especially if the patient cannot receive contrast intravenously, thereby delaying the appropriate treatment. Diffusion-weighted imaging (DWI) can help in many such situations by providing additional information, accurate characterization and defining the extent of the disease, so that prompt treatment can be initiated. In this article, we illustrate the imaging findings of the spectrum of musculoskeletal infections, emphasizing the role of DWI in this domain.

KEY POINTS

• Abscess in background cellulitis is detected on DWI. • Infectious tenosynovitis shows diffusion restriction as compared to mechanical tenosynovitis. • Pyomyositis with abscess can be differentiated from diabetic myonecrosis on DWI. • Intraosseous abscess is bright on DWI versus devitalized tissue, sequestrum and air. • DWI can be used to differentiate spine infection from simple Modic changes.

Pyomyositis Causing Temporary Quadriparesis During Induction Therapy for Acute Lymphoblastic Leukemia: Case Report and Review of the Literature

Pyomyositis (PM) is a purulent infection of skeletal muscle. It is often associated with immunosuppression in temperate climates. Herein, we report a case of PM causing temporary quadriparesis in a 14-year-old girl undergoing induction therapy for acute lymphoblastic leukemia and we review the reported pediatric cases associated with induction therapy for hematologic malignancies. Early symptoms of PM can be mistaken for the side effects of chemotherapeutic agents. Greater awareness of the clinical picture of PM will aid in early diagnosis and treatment. With appropriate medical therapy and timely abscess drainage, morbidity and mortality is greatly reduced.

Noninvasive imaging of Staphylococcus aureus infections with a nuclease-activated probe

Technologies that enable the rapid detection and localization of bacterial infections in living animals could address an unmet need for infectious disease diagnostics. We describe a molecular imaging approach for the specific, non-invasive detection of S. aureus based on the activity of its secreted nuclease, micrococcal nuclease (MN). Several short, synthetic oligonucleotides, rendered resistant to mammalian serum nucleases by various chemical modifications, flanked with a fluorophore and quencher, were activated upon degradation by recombinant MN and in S. aureus culture supernatants. A probe consisting of a pair of deoxythymidines flanked by several 2′-O-methyl-modified nucleotides was activated in culture supernatants of S. aureus but not in culture supernatants of several other pathogenic bacteria. Systemic administration of this probe to mice bearing bioluminescent S. aureus muscle infections resulted in probe activation at the infection sites in an MN-dependent manner. This novel bacterial imaging approach has potential clinical applicability for S. aureus and several other medically significant pathogens.