Detection and prevention of hospital-acquired staphylococcal infections in pregnant women and postpartum mothers – experience of “Prof. Dr. Panait Sîrbu” Clinical Hospital of Obstetrics and Gynecology, Bucharest

Introduction

Staphylococci are Gram-positive aerobic organisms. Staphylococcus aureus is the most pathogenic; it typically causes skin infections and sometimes pneumonia, endocarditis and osteomyelitis. It usually leads to the formation of abscesses. Some strains produce toxins that cause gastroenteritis, scalded skin syndrome and even toxic shock syndrome. The diagnosis is made through Gram staining and culture.

Staphylococcus aureus has the ability to cause the formation of vascular thrombi through coagulase (coagulase-positive staphylococci), and these are among the most virulent and dangerous pathogens that also have the capacity to develop resistance to antibiotics⁽¹⁾.

Coagulase-positive staphylococci are found on the skin of approximately 30-40% of the healthy population⁽²⁾.

Risk factors for staphylococcal infections

Individuals who are predisposed to infections include⁽³⁾:

• newborns and breastfeeding mothers
• patients with surgical incisions, open wounds or burns
• patients with influenza, chronic bronchopulmonary disorders (e.g., cystic fibrosis, emphysema), leukemia, tumors, chronic skin disorders or diabetes mellitus
• patients with transplants, prostheses or intravascular catheters
• patients receiving treatment with adrenal steroids, irradiation, immunosuppressants, or antitumor chemotherapy
• injecting drug users
• patients suffering from chronic kidney disease and undergoing dialysis.

Methicillin is a semi-synthetic derivative of penicillin, developed in the late 1950s, by modifying penicillin’s structure to provide resistance to penicillinase⁽⁴⁾.

The emergence of methicillin-resistant Staphylococcus aureus (MRSA) strains in the 1960s in the UK made the drug clinically ineffective. Methicillin resistance arises due to the acquisition of the mecA or mecC gene by previously susceptible staphylococcal strains⁽⁵⁾.

Predisposed patients can be infected with antibio­tic-resistant staphylococci from other patients, medical staff, or contaminated objects in hospitals or medical institutions. Transmission through medical staff hands is the most common mode of spread, but airborne transmission can also occur.

Complications and diseases caused by staphylococci

• Staphylococcal skin infections

Skin infections are the most common form of staphylococcal disease: 

1. Superficial infections can be diffuse, with pustules and vesicular crusts (impetigo – Figure 1)⁽¹⁾. Common sites of infection include the face (e.g., around the nose and mouth), the flexures, hands, and lower limbs⁽⁶⁾.
 

2. Cellulitis or focal infections with nodular abscesses (boils and carbuncles). Furunculosis is an inflammatory, draining, painful nodule that involves the hair follicle, typically following an episode of folliculitis (Figure 2)⁽¹⁾. A carbuncle is a series of interconnected boils in the subcutaneous tissue⁽⁷⁾.
 

3. Deeper skin abscesses are common. Severe necrotizing skin infections and postoperative wound superinfections can also occur (Figure 3).
 

4. Neonatal staphylococcal infections

Neonatal infections usually occur within four weeks after birth, including skin lesions with or without exfoliation, bacteremia, meningitis, pneumonia, endocarditis, osteomyelitis, staphylococcal joint infections, and toxic shock syndrome (Figure 4)⁽⁸⁾.
 

Screening for staphylococcal infection

At the “Prof. Dr. Panait Sîrbu” Clinical Hospital of Obste­trics and Gynecology, Bucharest, all hospitalized patients, including pregnant women, undergo screening for staphylococcal colonization or infection, by collecting nasal and axillary cultures, detecting over 80% of cases⁽⁹⁾. Patients who test positive and are not medical or surgical emergencies undergo general antibacterial cleaning (antiseptic soap, betadine) and local treatment with fusidic acid, followed by retesting. If hospitalization is required, cleaning is performed in the hospital, and patients with obvious infectious clinical signs are isolated.

In the neonatology departments, a second screening is performed to detect staphylococcal colonization and infection in newborns. 

If inflammation or erythema is observed on the skin and postoperative wounds, bacterial cultures are taken, including tests for staphylococcus and decolonization, and the infection prevention procedures are continued⁽¹⁰⁾.

Materials and method

Patients were recruited for the study from those hospitalized in the Obstetrics-Gynecology 1^st Ward during the first ten months of 2024, as well as from newborns from the Neonatology Departments (1^st and 2^nd). 

All patients underwent tests (bacterial cultures from the nose and skin in adult patients, and from the nose, ear and skin in newborns). 

The isolation of Staphylococcus aureus from wounds, purulent collections, and lochia meets the criteria for postoperative wound infection⁽¹¹⁾. 

All data were recorded and transmitted to the Bucharest Public Health Directorate. 

The identification of bacterial cultures was performed in our laboratory. Screening samples for Staphylococcus aureus were analyzed locally on chromogenic culture media, using standardized methods. The presence of Staphylococcus aureus was determined based on phenotypic criteria (pink or purple colonies). This culture medium has a sensitivity of 95.5% and a specificity of 99.4% for detecting Staphylococcus aureus⁽¹²⁾.

Missing information

We could not quantify the patients with Staphylococcus aureus positive results detected in the outpatient setting, decolonized, or treated at home who then tested negative on retesting. Therefore, the data we provide do not have the sensitivity to describe the level of contamination in the general population, but offer a “snapshot” of the contamination level among obstetrical patients hospitalized at the “Prof. Dr. Panait Sîrbu” Clinical Hospital of Obstetrics and Gynecology, Bucharest.

Results

The number of hospitalized patients from 1.01.2024 to 31.10.2024 in the Obstetrics-Gynecology 1^st Ward, including pregnant women, parturients and postpartum women, was 2193. 

The number of newborns hospitalized from 1.01.2024 to 31.10.2024 in the Neonatology Departments (1^st and 2^nd) was 1894 (Figure 5). 
 

Staphylococcus aureus was detected in 103 cases, with the following monthly distribution: 4.69% total prevalence of staphylococcal infection; 0.64% prevalence of MRSA. 

There were detected 14 MRSA-positive patients of the cases above, with the following sites of detection: 11 from nasal secretions, two from skin, and one from lochia cultures, which is about 14% of the cases. The weighted average in the general European population is 17.4%⁽¹³⁾.

In the neonatology departments, the screening results were very good, with 13 cases of Staphylococcus aureus contamination detected, of which nine cases were MRSA positive. 

The prevalence of MRSA-positive cases in the general neonatal population is estimated at 1.5%⁽¹⁴⁾, while in our case the prevalence in the neonatology departments was 0.45%.
 

Conclusions

1. The colonization rate with positive MRSA in pregnant women is, on average, 4.3%, according to international literature⁽¹⁵⁾. In our hospital, the contamination rate with MRSA was 0.64%. 

2. MRSA-positive colonization in neonatology departments ranges from 0.65% to 8.45% according to international literature⁽¹⁶⁾. In our hospital, it was 0.45%. 

3. The data obtained confirm the effectiveness of staphylococcal infection screening through the small number of contaminations in hospitalized obstetrical patients, further validated by the small number of MRSA contaminations in newborns.

Measures to increase the effectiveness of preventing staphylococcal infection:

a) Screening, individual isolation, cohort isolation of patients, and the use of gloves, gowns and face masks. 

b) Hand hygiene, including the use of antiseptics with water or alcohol-based hand gel, in the absence of water. 

c) Hygiene of the living environment, including cleaning, disinfection and sterilization procedures.

Autori pentru corespondenţă: Bogdan Botezatu E-mail: bogdan_zone@yahoo.com

CONFLICT OF INTEREST: none declared.

FINANCIAL SUPPORT: none declared.

This work is permanently accessible online free of charge and published under the CC-BY.