It’s all caused by Listeria monocytogenes

Preface

Preface

The elderly patient was admitted to the hospital for 2 days due to fever, had a history of cerebral infarction and brain atrophy for many years, and was unable to take care of himself
.

CT showed lacunar infarction, interstitial pneumonia, and pulmonary nodules

Listeria monocytogenes is a Gram-positive microbacteria, which exists widely in nature
.

It often causes infectious mononucleosis with Epstein-Barr virus, and can also cause meningitis and bacteremia

Case history

Case history

Medical history and physical examination: The patient is an elderly female with a history of cerebral infarction and brain atrophy for many years and cannot take care of herself
.

Two days ago, the patient developed fever without obvious cause, which was persistent.

Admission physical examination: T38℃, P90 beats/minute, R22 beats/minute, Bp: 118/76mmHg, general state is not good, and his speech is slow, he is pushed into the ward, and the physical examination is cooperative
.

No cyanosis of the lips, no congestion in the pharynx, weak breath sounds in both lungs, wet rales, heart rate 90 beats/min, rhythm, no pathological murmurs in the heart valve area, soft abdomen without tenderness, liver and spleen not touched , Slightly edema of both lower limbs

Laboratory inspection:

Laboratory inspection:

Film degree exam:

Film degree exam:

Brain CT: Lacunar Infarction

Lung CT: interstitial pneumonia, pulmonary nodules

Discharge diagnosis:

Discharge diagnosis:

Bacteremia; interstitial pneumonia; pulmonary nodules; lacunar cerebral infarction
.

After diagnosis and treatment:

After diagnosis and treatment:

Upon admission, he was sent for blood culture and was given cefoperazone, tazobactam, doxofylline, and ambroxol hydrochloride for anti-inflammatory, antispasmodic, and phlegm-resolving supportive and symptomatic treatments
.

During this period, the patient's fever symptoms were relieved, but there were still recurrences

case analysis

case analysis

Clinicians

Clinicians

Patients with bacteremia usually present with fever and chills, and nearly a quarter of patients have had diarrhea [2]
.

If the disease is not controlled in time, septic shock can develop, but it is rare

Examiner

Examiner

If Gram-positive, regular Brevibacterium is cultured in cerebrospinal fluid or blood samples, the possibility of Listeria monocytogenes infection should be suspected first
.

However, because Listeria monocytogenes can be arranged in a "V" shape or fence shape, it is easy to be mistaken for other Gram-positive non-pathogenic bacteria such as Corynebacterium during the primary reporting stage of a positive blood culture [3]

For the above reasons, accurate and rapid strain identification is particularly important for the selection of drug susceptibility tests and clinical treatment
.

Matrix-assisted laser analysis and ionization time-of-flight mass spectrometry (MALDI-TOFMS) can quickly identify Listeria bacteria with its own analysis software, and can carry out simple molecular and phylogenetic studies.

Knowledge development

Knowledge development

Listeria monocytogenes is gram-positive, non-spore-free, facultative anaerobic, non-mycobacterium (0.
5-2μm in length, 0.
4-0.
5μm in diameter), and its cells are arranged in single or short chains
.
Listeria can grow at 0-50°C, the optimum temperature is 30-37°C, and it can grow slowly at 4°C
.
After culturing on nutrient medium at 37°C for 1-2 days, small colonies with a smooth gray-blue surface with a diameter of 1-2mm can be formed, and a narrow β-hemolytic ring can be seen under the irradiation of transmitted light
.

Among adults, Listeria monocytogenes mainly causes primary sepsis, meningitis and encephalitis, with high mortality
.
The median incubation period of Listeria bacteremia is 2 days, and the amount of infectious bacteria is not yet clear
.
However, whether invasive infection occurs after ingestion of Listeria monocytogenes is related to the pathogen and the host's own conditions
.

The virulence genes of Listeria are mainly concentrated on an 8.
2 kb virulence island.
The virulence genes include internalization protein, phosphatidylinositol-specific phospholipase, actin polymer protein and metalloprotease.
The expression of these genes is affected by Positive regulator A (PrfA) control
.

Summary

Summary

The patient in this case is an elderly female with obvious symptoms of chills and fever but no diarrhea
.
According to the admission form, it can be known that the patient's C-reactive protein, procalcitonin and other indicators can indicate that the patient is a disease caused by a bacterial infection, but the specific pathogen still needs to wait for the laboratory to report
.
In addition, due to the poor basic condition of the patient, considering that the possibility of mixed bacterial infection and pathogen resistance cannot be ruled out, cefoperazone and tazobactam were used as antibacterial drugs in the early stage
.
Fortunately, the susceptibility of the bacteria was reported to be susceptible in the later stage.
After communicating with the microbiology room, the combination of penicillin and gentamicin was replaced, and the patient recovered and was discharged from the hospital
.

Expert Reviews

Expert Reviews

Isolation of Listeria monocytogenes from blood and other sterile body fluids is currently the only way to diagnose listeriosis.
If Listeria is found in clinical culture, it should be identified in time to identify whether the isolated bacteria are pathogenic Listeria.
At the same time, communicate with clinicians as soon as possible to correctly choose antibacterial drugs for treatment
.
The CLSI guideline (M45-A2) provides the breakpoints and interpretation criteria of this bacterium against penicillin, ampicillin and trimethoprim-sulfamethoxazole[8].
At the same time, there are literature reports on the effect of erythromycin on Listeria monocytogenes.
Sensitive conclusion of foreign drug susceptibility test
.

On the other hand, because aminoglycoside drugs and penicillin drugs have a synergistic effect, this is the reason why we finally choose the combination of these two drugs
.
The final cure of the patient in this article is the joint contribution of the clinician's early and accurate inspection items and the rapid and accurate identification of the inspectors and the return of the drug sensitivity results
.
In this case, the importance of timely and effective communication between clinic and laboratory is reflected
.

(Commenter: Zou Guiling, Deputy Chief Technician of the Laboratory Department of the Fourth Affiliated Hospital of Harbin Medical University)

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