Microbiology Case Study: A Routine Sputum Culture on a 20 Year Old Cystic Fibrosis Patient

Case History

A 20 year old woman with cystic fibrosis was routinely screened with bacterial sputum cultures.  The patient reported feeling well and was compliant with her treatment regimen.  She had no history of Nocardia colonization in the past and her last hospitalization was four years prior due to a pulmonary exacerbation in which cultures grew Stenotrophomonas and Pseudomonas.

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Image 1: Modified acid fast stain showing two unique traits of Nocardia: long, delicate rods and weak acid fastness.

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Image 2: Nocardia colonies on buffered charcoal yeast extract (BCYE) agar.

Discussion

Nocardia are slow growing, aerobic gram negative rods. Nocardia are unique for being weakly acid fast and displaying aerial hyphae.  They are ubiquitous organisms that can cause a variety of infections in immunocompromised individuals. Most often in the United States, nocardiosis causes a lung infection. If left untreated, it can spread to the brain or spinal cord, where up to 44% die [1].

The above patient showed no signs of an infection, making the possibility of colonization by Nocardia more likely.  Cystic fibrosis patients can be colonized by Nocardia and the clinical approach is to treat regardless of the patient’s overall health. However, there is a lack of reporting on whether Nocardia is the cause of an infection when it happens. Host and pathogen interactions are also not well known. Thorn et al. showed that treating cystic fibrosis patients that are colonized with Nocardia with oral antibiotics did not affect their clinical outcome [2]. More studies are needed to be done to see if antibiotics are warranted in circumstances like the above patient.

References:

  1. Nocardiosis. https://www.cdc.gov/nocardiosis/transmission/index.html
  1. Pulmonary nocardiosis in cystic fibrosis. Thorn, Shannon T. et al.. Journal of Cystic Fibrosis, Volume 8 , Issue 5 , 316 – 320

 

-Angela Theiss is a pathology resident at the University of Vermont Medical Center.

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-Christi Wojewoda, MD, is the Director of Clinical Microbiology at the University of Vermont Medical Center and an Associate Professor at the University of Vermont.

Microbiology Case Study: An Elderly Man with Abdominal Pain

Case History

The lab received two sets of admission blood cultures from an elderly man with a history of atrial fibrillation, aortic valve replacement six years ago, and idiopathic pancytopenia who presented with abdominal pain and symptoms of decompensated heart failure.

Lab Identification

At 59 hours, one aerobic bottle showed growth of a gram negative bacillus. The organism grew pure yellow-pigmented colonies on the blood and chocolate plates with no growth on the MacConkey plate.

breves4
Gram stain from blood agar plate.

The Verigene microarray was not able to identify the organism against 12 gram negative targets. The organism was identified by MALDI-TOF mass spectrometer as Brevundimonas vesicularis. The organism could not be grown for susceptibility testing.

Discussion

B. vesicularis is an aerobic, glucose non-fermenting, spore non-forming, gram negative bacillus closely related to Pseudomonas species. It will demonstrate slow growth of yellow-pigmented colonies on chocolate and blood agar plates with variable growth on MacConkey agar plates. It has in the past been classified as Corynebacterium and Pseudomonas vesicularis. It has been identified globally in environmental sources such as soil, spring water, and healthcare related water containers. It has been identified as a community-acquired, and increasing a hospital-acquired, pathogen in all age groups, and particularly in immunocompromised patients [1, 2]. It has been most commonly reported as a cause of bacteremia, but has also been implicated as the causative agent in cases of arthritis, meningitis, endocarditis, peritonitis, and urinary tract infection [1]. Interesting in vitro studies have demonstrated that the presence of B. vescularis may facilitate the growth of Legionella [3].

Even in cases of the septicemia in immunocompromised patients the mortality rate from B. vesicularis is relatively low. Strains have demonstrated resistance to most forms of antibiotics though is most consistently susceptible to amikacin and piperacillin-tazobactam [1, 2].

 

References

  1. Shang ST, Chiu SK, Chan MC, Wang NC, Yang YS, Lin JC, Chang FY. Invasive Brevundimonas vesicularis bacteremia: Two case reports and review of the literature. J Microbiol Immun Inf. (2012) 45: 468-472.
  2. Zhang CC, Hsu HJ, Li CM. Brevundimonas vesicularis bacteremia resistant to trimethoprim-sulfamethoxazole and ceftazidime in a tertiary hospital in southern Taiwan. J Microbiol Immunol Infect. (2012) 45(6): 448-452.
  3. Koide M, Higa F, Tateyama M, Cash HL, Hokama A, Fujita J. Role of Brevundimonas vesicularis in supporting the growth of Legionella in nutrient-poor environments. New Microbiol. (2014) 1:33-39.

 

-Taylor Goller is a Pathology Student Fellow at University of Vermont Medical Center.

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-Christi Wojewoda, MD, is the Director of Clinical Microbiology at the University of Vermont Medical Center and an Associate Professor at the University of Vermont.

Microbiology Case Study: A 7 Month Old Female with Fever and Seizure-Like Episodes

Case History

A 7 month old female presented to the emergency department (ED) due to fever and seizure-like episodes. Her mother reported the child had been persistently febrile for 5 days (Tmax 103.9°F) with rhinorrhea, fussiness and decreased oral intake. The patient experienced 3 seizure-like episodes on the day of admission, which the mother described as periods of “shaking” with eyes rolling back. The child was unresponsive during these episodes, which lasted 1 to 2 minutes each. The child had been taken to her pediatrician the day prior to presentation to the ED where she was given a shot of ceftriaxone for presumed otitis media. The child received a chest x-ray, influenza testing, and blood and urine cultures were collected. She also had a lumbar puncture performed and the cerebral spinal fluid (CSF) was sent for chemistries, bacterial culture and polymerase chain reaction (PCR) testing for meningitis/encephalitis pathogens. She was started on IV ceftriaxone.

Laboratory Testing

The child’s white blood cell count from peripheral blood was 7.1 TH/cm2 and chest x-ray, urinalysis and flu testing were unremarkable. The CSF was clear and colorless with 7 WBC/cm2, glucose of 57 mg/dL and protein of 21 mg/dL. The cytospin Gram stain identified no organisms. The meningitis/encephalitis panel detected the presence of human herpesvirus 6 (HHV-6).

Discussion

Human herpesvirus 6 is a member of the Herpesviridae family and was the sixth herpes virus identified. Structurally, HHV-6 possesses a double stranded DNA genome and is enveloped. Clinically, it is the etiologic agent of roseola infantum (exanthum subitum) in infants and toddlers. Primary infection occurs in early childhood and those infected can be asymptomatic or have a non-specific febrile illness while only the minority present with the characteristic red macular rash prominent on the trunk and extremities, lymphadenopathy and high fevers. HHV-6 is highly neurotropic and as such causes viral encephalitis with 5-15% of children experiencing febrile seizures as a result of this illness. HHV-6 is highly prevalent with a greater than ninety percent seropervalence rate. HHV-6 establishes latency in T lymphocytes and can reactivate & cause disease, especially in immunocompromised patients such as those recipients of stem cell or solid organ transplants.

Traditional laboratory methods of identification for HHV-6 were challenging as viral culture, while once the gold standard for active disease, is not practical for most labs and is no longer used in routine diagnostics. PCR from serum, plasma or CSF has become the preferred test as there are now FDA-cleared, commercial platforms that are easy to use, allow for rapid turnaround time and in the case of multiplex PCR panels, the ability to target multiple pathogens from one test. Serology, while helpful in the diagnosis of primary infections, may not be provide conclusive results in a timely manner and is of limited utility in reactivation. Other less commonly used methods include immunohistochemistry, in situ hybridization and electron microscopy.

The prognosis for patients infected with HHV-6 is generally good with self-limited illness not requiring treatment. Rarely, multi-organ involvement can occur and HHV-6 infection in immunosuppressed patients can be a major cause of morbidity and mortality. There is no antiviral therapy licensed for the treatment of reactivated disease in this setting, but approaches using ganciclovir and valganciclovir have been proposed.

In the case of our patient, her blood, urine and CSF cultures were negative and her antibiotics were stopped after cultures were no growth at 24 hours. She required no treatment other than supportive care with acetaminophen for fever control. Prior to discharge, she developed a fine rash on her face, the back of her neck and trunk that was characteristic of an HHV-6 rash. This case demonstrates the utility of multiplex PCR testing in providing rapid identification of pathogenic organisms allowing for real time diagnosis and the limiting of unnecessary treatment.

 

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-Eric Tillotson, MD, is a second year Anatomic and Clinical Pathology resident at the University of Mississippi Medical Center.

Stempak

-Lisa Stempak, MD, is an Assistant Professor of Pathology at the University of Mississippi Medical Center in Jackson, MS. She is certified by the American Board of Pathology in Anatomic and Clinical Pathology as well as Medical Microbiology. She is the director of the Microbiology and Serology Laboratories. Her interests include infectious disease histology, process and quality improvement and resident education.

 

 

Microbiology Case Study: A 56 Year Old Woman with Purulent Vaginal Discharge and Dysarthria

Case History

The lab received a purulent fluid from a frontal subdural empyema in a 56 year old woman with a several month history of sporadic bloody to purulent vaginal discharge and a two week history of severe headache, facial weakness, and recent dysarthria causing her to seek treatment. Pelvic exam and CT of the abdomen revealed a fungating cervical mass, later found to be adenocarcinoma, with possible fluid collection within the uterine cavity.

Lab Identification

Initial gram stain of the subdural fluid showed moderate neutrophils and no bacteria. The aerobic plate showed no growth at 48 hours. The thioglycollate broth grew “puffballs” containing long gram negative bacilli with tapered ends.

 

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Anaerobic blood agar plate on day 9. Note: large white colonies are contamination.
fusnuc2
Gram stain from anaerobic plate on day 9.

The anaerobic plate grew few grey colonies composed of similarly-shaped gram negative bacilli. MALDI-TOF mass spectrometer identified both colony morphologies as Fusobacterium nucleatum.

Discussion

F. nucleatum is a gram negative, spore non-forming, asacchrolytic, slow-growing, obligate anaerobe that can fluoresce chartreuse under UV light. It is one of 14 species within the Fusobacterium genus and is further classified into 5 subspecies (nucleatum, animalis, fusiforme, vincentii, and polymorphum) which have different pathogenic profiles. It is commonly associated with the oral cavity, though it is unclear if it is ever a constituent of usual flora. Its main virulence factors are invasion of epithelial and endothelial cells, induction of host immune response, and adhesion to tissue through a variety of adhesins. The FadA adhesin interacts with the ubiquitous cell junctional cadherins leading to increased permeability of the epithelial and endothelial barrier. This interaction may be why F. nucleatum infections can be found in such diverse locations within the body and are often part of a polymicrobial infection [1, 2].

F. nucleatum is a constituent of oral plaque and is strongly associated with gingivitis and periodontitis. It is present in increased quantity with increasing severity of disease and in patients with a history of smoking or uncontrolled diabetes mellitus. It is a known pathogen in infections and abscesses of the head and neck, brain, lung, abdomen, blood, and pleura. It is also commonly found in placental and fetal tissues and strongly associated with a variety of obstetrical conditions including preterm birth, chorioamnionitis, and neonatal sepsis. It has been implicated in at least one case as the causative agent of stillbirth. Its prevalence in cord blood in cases of neonatal sepsis is equal to or greater than that of E. coli and Group B Strep. There is also a known association between F. nucleatum and colorectal cancer and IBD, with current research investigating whether the bacteria could play a role in pathogenesis. [1].

F. nucleatum is generally responsive to treatment with a range of antimicrobials, though there are reports of strains resistant to clindamycin and beta-lactamase-based resistance to ampicillin [2, 3].

The infectious disease clinician covering the present case suggested that the patient may have been transiently bacteremic due to her fungating gynecologic malignancy and suffered a minor head trauma causing a small subdural hemorrhage that seeded the bacteria in a sufficiently protected anaerobic environment.

 

References

  1. Han TW. Fusobacterium nucleatum: a commensal-turned pathogen. Curr Opin Microbiol. (2015) 23:141-147.
  2. Denes E, Barraud O. Fusobacterium nucleatum infections: clinical spectrum and bacteriological features of 78 cases. Infection (2016) 44:475-481.
  3. Veloo ACM, Seme K, Raanges E, Rurenga P, Singadji Z, Wekema-Mulder G, van Winkelhoff AJ. Antibiotic susceptibility profiles of oral pathogens. Intl J Antimicrob Agents. (2012) 40:450-454.

 

-Taylor Goller is a Pathology Student Fellow at University of Vermont Medical Center.

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-Christi Wojewoda, MD, is the Director of Clinical Microbiology at the University of Vermont Medical Center and an Associate Professor at the University of Vermont.

 

Microbiology Case Study: A 16 Year Old with Rhinosinusitis

Case

A 16-year-old male presented with recurrent sinusitis and rhinitis. He had a history of left sinus surgery two years ago, and at that time pathologic examination of the tissue demonstrated eosinophilia and fungal culture grew Curvularia, consistent allergic fungal sinusitis. The patient was doing well without allergy or immunotherapy management until three months ago when he could not breathe out of the right nostril and began snoring loudly. He underwent bilateral endoscopic frontal sinusotomy with tissue removal of the ethmoid and sphenoid sinuses. Tissue was sent to the laboratory for fungal culture. After five days, fungal cultures grew mold on inhibitory mold agar with gentamicin. The surface was a gray speckled color (Image 1C). The reverse color of the mold colony was dark brown to black. The microscopic appearance can be seen in Image 1A-B.

Bipolaris figure
Image 1. A) Ellipsoid conidia with the common number of 3-5 septations stained with lactophenol cotton blue counterstain, B) a cluster of conidia surrounded by less lactophenol cotton blue stain better demonstrating brown melanin pigment in the cell wall, and C) a dark gray speckled fungal colony.

 

Discussion

These features are consistent with the identification of Bipolaris. Microscopic examination using lactophenol cotton blue tape prep demonstrated oblong conidia characteristic of Bipolaris (Image 1 A-B). The conidia are ellipsoidal with pale brown pseudoseptations that contain three to five septa. Four septa are the most common. Bipolaris is a dematiaceous fungus, meaning the cell walls contain dark brown melanin pigment. This can be seen by microscopic observation of the fungal cell wall which contains pigment (Image 1B) and is also demonstrated by the dark reverse color of the fungal colony.

To distinguish Bipolaris from Drechslera and Exserohilum, the Germ tube test can be utilized. When conidia are incubated with a drop of water on a glass slide for 8-24 hours, they will begin to form Germ tubes. Bipolaris species germinate from both poles of the oblong conidium at a 180 degree angles (hence the name “Bipolaris”), whereas Exserohilum germinate from just one pole at a 180 degree angle and Dreschslera species germinate at a 90 degree angle from the central cells of the conidium. Dreschslera can be confused for Bipolaris based on colony appearance and microscopic appearance, but unlike Bipolaris, Dreschslera is not associated with human disease.1

Pathogenic strains of Bipolaris include Bipolaris australiensis, Bipolaris hawaiiensis, Bipolaris maydis, Bipolaris melanidis, Bipolaris speicifera, and Bipolaris sorokiniana.2 The most common cause of infection is Bipolaris spifcifera. Bipolaris species are the most common cause of fungal sinusitis in immunocompetent individuals which often presents as allergic rhinitis. Allergic rhinitis could also be a risk factor for acquiring Bipolaris. Treatment often consists of prompt surgical excision to prevent expansion, superficial deformity and dissemination. If fungal chemotherapy is pursued, itraconazole and amphoterin B have been reported as effective agents.3

Bipolaris is one of the most common causes of allergic fungal sinusitis, typified by nasal polyps and mucus plugs consisting of eosinophils, fungal hyphae and Charcot-Leyden crystals. It is a type 1 and 3 hypersensitivity reaction mediated process due to high levels of mold-specific IgE.4 Skin prick testing is also positive in patients with allergic fungal rhinosinusitis (AFRS) which further indicates that the pathophysiology is an immunologic versus infectious process.4 While the exact process of fungal allergic sensitization has not been codified, chitin, a structural fungal protein has been shown to elicit a Th2 immune response.5 It will be interesting to see how this research evolves so that we might one day see why fungi can cause both erosive infections and allergies within human patients.

 

References

  1. Fothergill AW. Identification of Dematiaceous Fungi and Their Role in Human Disease. Clin Infect Dis. 1996; 22 (S2): S179-84.
  2. Shafili SM, Donate G, Mannari RJ, Payne WG, Robson MC. Diagnostic Dilemmas: Cutaneous Fungal Bipolaris Infection. Wounds. 2006; 18(1):19-24.
  3. Saenz RE, Brown WD, Sanders CV. Allergic Bronchopulmonary Disease Caused by Bipolaris hawaiiensisPresenting as a Necrotizing Pneumonia: Case Report and Review of Literature. The American Journal of Medical Sciences. 2001; 321(3):209-12.
  4. Manning SC, Holman M. Further evidence for allergic pathophysiology in allergic fungal sinusitis. Laryngoscope. 1998;108(10):1485–1496.
  5. Reese TA, Liang HETager AMLuster ADVan Rooijen NVoehringer DLocksley RM. Chitin induces accumulation in tissue of innate immune cells associated with allergy. Nature 2007; 3;447(7140):92-6.

 

 JS

-Jeffrey SoRelle, MD, is a 1st year Clinical Pathology Resident at UT Southwestern Medical Center.

Erin McElvania TeKippe, PhD, D(ABMM), is the Director of Clinical Microbiology at Children’s Medical Center in Dallas Texas and an Assistant Professor of Pathology and Pediatrics at University of Texas Southwestern Medical Center.

Microbiology Case Study: Elderly Woman with Signs of Shock

Case History

The lab received two sets of blood cultures drawn at the time of admission from an elderly woman presenting with escalating signs of shock in the setting of suspected ischemic bowel. An exploratory laparotomy led to resection of a gangrenous segment of large bowel without signs of perforation or abscess. The woman’s medical history in the previous three months included two episodes of GI bleed, including one associated with signs of ischemic bowel, treated conservatively, and a hospitalization for health care acquired pneumonia treated with levofloxacin and steroids.

Lab Identification

Bacterial growth was detected in two bottles from one site. The anaerobic bottle demonstrated gram negative bacilli. The aerobic bottle demonstrated gram positive cocci that were identified by the Verigene microarray as non-VRE Enterococcus faecium. However the Verigene system could not identify the gram negative rod.

The gram negative rod grew on blood, chocolate, and McConkey agar. It was a lactose non-fermentor. Additionally, the gram negative colonies were indole positive and oxidase negative.

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Image 1. Gram stain of anaerobic blood culture bottle.

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Image 2. Blood and MacConkey agars with growth of the organism.

 

These colonies were identified by the MALDI-TOF mass spectrometer as Escherichia fergusonii.

Discussion

Originally described as a unique species in 1985, Escherichia fergusonii is the closest relative of the much more common and well-known Escherichia coli.1 It is differentiated from E. coli by being lactose and sorbitol negative but adonitol, amygdalin, and cellobiose fermentation positive. Due to its molecular and structural similarities to E. coli, platforms such as the MALDI-TOF or Vitek 2 may have difficulty discriminating between the two species.2, 3 It has been identified as normal intestinal flora of warm blooded animals, though not specifically humans, and has been implicated in a salmonellosis-like disease in sheep and cattle.3

Descriptions in the literature regarding the clinical relevance of E. fergusonii to human disease are limited. There have been reports of E. fegusonii acquiring known virulence factors from E. coli and Salmonella, however, the prevalence and significance of such transformation is not well understood. In one report, E. fergusonii was found to have acquired the E. coli O157 antigen, but did not acquire the associated virulence factors or Shiga toxin.4 It has been identified as the pathogenic agent in cases of urinary tract infection, wound infection, diarrhea, bacteremia, cholangiosepsis, pleuritis, and endopthalmitis. These reports are geographically widespread with E. fergusonii identified in patients from the US, Nicaragua, Italy, India, and Taiwan. There is also variable information on antimicrobial susceptibility. The original description by Farmer et al. reported that all strains were susceptible to colistin, gentamicin, and chloramphenicol, and resistant to penicillin.1 An analysis of 600 specimens from eastern India revealed high rates of resistance to gentamicin and chloramphenicol and moderate resistance to ampicillin.5 An analysis of urinary tract infection specimens from Nicaragua reported resistance to nitrofuratoin, ciprofloxacin, ceftriaxone, and amoxicillin-calvulanate.6

Interestingly, E. fergusonii has been identified as the most quickly evolved member of the Escherichia genus.7 Though it is unclear whether that rapidity of differentiation translates to an ability to acquire clinical relevant features, it can at least be concluded E. fergusonii is a widely distributed and possibly under-identified gram negative facultative bacillus with the potential to acquire virulence factors and antibiotic resistance that could make it a significant pathogenic organism in humans.

References

  1. Farmer JJ, Fanning GR, Davis BR, O’Hara C, Riddle C, Hickman-Brenner FW, Asbury MA, Lowery VA, Brenner DJ. Escherichia fergusonii and Enterobacter taylorae, two new species of Enterobacteriaceae from clinical specimens. J. Clin. Microbiol., 21 (1985): 77–81.
  2. Crawford-Miksza LK, Himathongkam S, Dodd ML, Badoiu AS, Badoiu OM, Guthertz LS. Misidentification of a variant biotype of Escherichia coli O157:H7 as Escherichia fergusonii by Vitek 2 compact. J. Clin. Microbiol., 47 (2009): 872–873.
  1. Gastra W, Kusters JG, van Duijkern E, Lipman LJA. Escherichia fergusonii. Vet. Microbiol., 172 (2014): 7-12.
  1. Fegan N, Barlow RS, Gobius KS. Escherichia coli O157 somatic antigen is present in an isolate of E. fergusonii. Curr. Microbiol., 52 (2006): 482–486.
  1. Mahapatra A, Mahapatra S, Mahapatra A. Escherichia fergusonii: an emerging pathogen in South Orissa. Indian J. Med. Microbiol., 23 (2005): 204–208.
  1. Bours PHA, Polak R, Hoepelman AIM, Delgado E, Jarquin A, Matute AJ. Increasing resistance in community-acquired urinary tract infections in Latin America, five years after the implementation of national therapeutic guidelines. Int. J. Infect. Dis., 14 (2010): e770–e774.
  2. Walk ST, Alm EW, Gordon DM, Ram JL, Toranzos GA, Tiedje JM, Whittam TS. Cryptic lineages of the genus Escherichia. Appl. Environ. Microbiol., 75 (2009): 6534–6544.

 

-Taylor Goller is a Pathology Student Fellow at University of Vermont Medical Center.

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-Christi Wojewoda, MD, is the Director of Clinical Microbiology at the University of Vermont Medical Center and an Assistant Professor at the University of Vermont.

Microbiology Case Study: A 34 Year Old Female with Nausea, Vomiting, Diarrhea and Tender Extremities

Case History

A 34 year old female presented to the emergency department with a chief complaint of nausea, vomiting and diarrhea as well as tenderness in her extremities. These symptoms had been present for the previous 4 days with multiple episodes of diarrhea, associated low grade fevers & chills and she had poor oral intake as a result. Her past medical history was significant for human immunodeficiency virus (HIV) and chronic kidney disease. She has not be compliant with her anti-retroviral therapy and infectious disease prophylactic medications. Her vitals were within normal range and her physical exam elicited tenderness to palpation of her extremities and torso. No rashes and no erythema are seen. Routine laboratory tests as well as infectious disease work up, which included blood, stool & urine cultures, C. difficile and ova & parasite exam, were ordered. Notable findings included a slightly elevated white blood count (11.3 TH/cm2), creatinine of 7.1 mg/dL, HIV RNA viral load of 671 VC/mL and an absolute CD4 count of 7 cells/cm2. Two days after collection, her blood cultures were signaled as positive by the automated instrument.

Laboratory Identification

ngono1
Image 1. Gram stain from the blood culture bottles showed Gram negative cocci arranged in pairs (1000x oil immersion).
ngono2.png
Image 2. Small, whitish glistening colonies grew on blood and chocolate agars after 48 hours incubation in a 35°C incubator with 5% CO2.

The pathogen of interest grew from two sets of blood cultures and the direct Gram stain showed Gram negative cocci arranged in pairs (Image 1). After 48 hours incubation, small, whitish colonies were observed on blood and chocolate agars. No growth was seen on the MacConkey plate (Image 2). The isolate was positive for both catalase and oxidase. It was identified as Neisseria gonorrhoeae by both MALDI-TOF MS and a Vitek NH card.

Discussion

N. gonorrhoeae is the second most common sexually transmitted infection (STI) in the United States, only surpassed by Chlamydia trachomatis and they are often acquired together as a co-infection. Uncomplicated infections with N. gonorrhoeae typically present as acute urethritis with discharge. Asymptomatic infection occurs in 10% of males and upwards of 50% of females. As a result, females are at risk for the development of ascending infections and pelvic inflammatory disease leading to further reproductive issues. Disseminated gonococcal infection is uncommon (less than 1% of all gonococcal infections) but can occur and manifests as purulent arthritis with or without an accompanying dermatitis. In the case of our patient, her tenderness to palpation of the extremities could be a symptom of this disseminated septic arthritis.

In the laboratory, N. gonorrhoeae can be fastidious and requires special media such as chocolate, Martin-Lewis, modified Thayer-Martin or New York City agars as well as an enhanced CO2 environment in order to grow. The Gram stain of N. gonorrhoeae is described as Gram negative cocci with adjacent flattened sides and helpful biochemicals include catalase and oxidase (both positive).  Traditionally, in order to further speciate members of the Neisseria genus, sugar fermentation was necessary. N. gonorrhoeae only ferments glucose, while another notable member, N. meningitides, ferments both glucose and maltose.  Additionally, N. lactamica ferments glucose, maltose and lactose. Currently, commonly used methods of identification include API NH strips and automated instruments such as Vitek and MALDI-TOF MS.

Susceptibility testing for N. gonorrhoeae is usually limited to testing for beta-lactamase activity, although CLSI guidelines are available if deemed necessary. Current therapeutic guidelines recommend empiric treatment of uncomplicated infections with intramuscular ceftriaxone and oral azithromycin.

 

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-Kristen Adams, MD, is a fourth year Anatomic and Clinical Pathology resident at the University of Mississippi Medical Center. 

Stempak

-Lisa Stempak, MD, is an Assistant Professor of Pathology at the University of Mississippi Medical Center in Jackson, MS. She is certified by the American Board of Pathology in Anatomic and Clinical Pathology as well as Medical Microbiology. She is the director of the Microbiology and Serology Laboratories.  Her interests include infectious disease histology, process and quality improvement and resident education.