JSTOR

Case Report

The patient, a full‐term newborn female, was born at another hospital by normal spontaneous vaginal delivery with a breech presentation. At birth, she had hypoxic ischemic encephalopathy, and her initial weight was 2.250 kg. The next day, the patient was intubated and mechanically ventilated for cardiopulmonary arrest after aspiration. She was subsequently transferred to the NICU at Dhahran Health Center (Dhahran, Saudi Arabia). She was given ampicillin and gentamicin for 7 days and received no other antibiotics.

The infection control policy at Dhahran Health Center requires that all patients transferred from outside hospitals to an ICU in the hospital undergo screening for detection of MRSA. Results of initial screening of nasal swab specimens and cultures of respiratory specimens were negative for MRSA. Five weeks into the patient's hospital course, however, culture of a respiratory specimen yielded MRSA, but she had no signs or symptoms of pneumonia.

The infant’s parents were healthy with no significant past medical history. The parents had not recently received medical treatment or undergone surgery, and they were not HCWs. According to our hospital policy, even a solitary case of MRSA colonization or infection in the NICU is considered an outbreak. Thus, screening of nasal swab specimens obtained from all 93 NICU HCWs, the other 26 patients who were in the NICU during the preceding 5 weeks, and the parents of the neonate was performed. The neonate and her father tested positive for MRSA; the mother, HCWs, and remaining patients tested negative for MRSA.

The 2 strains of MRSA obtained from the patient and her father had a similar antibiogram; both strains were susceptible to ciprofloxacin, clindamycin, erythromycin, and vancomycin. The strains were resistant to tetracycline, penicillin G, and oxacillin. Both strains were sent to Mayo Medical Laboratories (Rochester, MN) for pulsed‐field gel electrophoresis (PFGE), which revealed that the 2 isolates had indistinguishable PFGE patterns.

Discussion

It is known that nosocomial MRSA infection or colonization is usually associated with transmission from an infected or colonized patient, a hospital source, or, occasionally, from a colonized HCW.⁸ In outbreaks of MRSA infection and colonization in the NICU, HCWs were found to be transiently colonized of MRSA, with subsequent transmission of this pathogen to their families.^5,9,10 In another study from Japan, an outbreak of MRSA infection in the NICU was traced to colonized healthcare workers.¹¹ Familial transmission of nosocomial or community‐acquired MRSA from patients to their household contacts has also been reported.¹² Mother‐to‐infant transmission has been shown to occur in 4 pregnant women and their infants.¹³ In a report by Hollis et al.,⁸ a strain of MRSA that was initially transmitted among family members was subsequent transmitted to a neonate in the NICU. Antibiograms and DNA analysis confirmed that the isolates from the mother and the neonate were identical.⁸ In another report, the MRSA strain from a NICU outbreak was derived from the mother of an infant with a low birth weight.¹⁴ In another report from a NICU, the transmission of MRSA from a mother to 3 of her preterm quadruplet infants occurred postnatally.¹⁵ However, it was not known whether the strain from the mother was hospital‐acquired MRSA or CA‐MRSA.

CA‐MRSA has been described in children with and children without identifiable risk factors.¹⁶ The reported prevalence of CA‐MRSA has varied and has depended on the geographic location of the study and the various definitions used. Individuals with MRSA infection or colonization may spread the organism within households and to other contacts in the community.¹⁷ In a study from Toronto, a child infected with CA‐MRSA transmitted the pathogen to others in a day care center.¹⁸ In another report, CA‐MRSA was transmitted from a mother to her child in a NICU.⁶

Here, we describe the transmission of CA‐MRSA from a father to his infant. We are not aware of any previous report of such a transmission. The father had not recently undergone surgery or received medical treatment. In addition, a nasal swab specimen from the mother tested negative for MRSA. Thus, it seems likely that the father transmitted CA‐MRSA to the infant. Because the strains were indistinguishable from each other by PFGE, the findings confirm that the isolates were related and that a directional transmission had occurred from the father to the neonate. This is further substantiated by the fact that the mother, all 93 HCWs, and all 26 other neonates in the NICU tested negative for MRSA.

The recognition that CA‐MRSA may be transmitted in the hospital setting raises important issues for MRSA infection control. Whether routine screening of parents of neonates should be done is a question that remains to be answered. If further evidence links high and significant transmission rates of CA‐MRSA from parents to newborns, then screening of family members may be indicated. Such a recommendation has only been suggested by a single author.⁸ In addition, screening of family members for MRSA has been recommended by another author for patients undergoing continuous ambulatory peritoneal dialysis.¹⁹

In conclusion, the possibility of the transmission of MRSA by parents, family members, and visitors should be considered when investigating a nosocomial outbreak of CA‐MRSA colonization or infection in a NICU. In addition, the health and occupational histories of all parents need to be considered.