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Methicillin resistant Staphylococcus aureus (MRSA) is an infrequent cause of external ocular infections. Patients typically have underlying ocular risk factors or are medically debilitated.1 We describe a case of neonatal conjunctivitis due to MRSA and discuss its implications.
A 7 day old neonate was referred to the ophthalmology team with a day’s history of purulent right conjunctivitis. The baby had been born at term by normal vaginal delivery; however the amniotic membrane had ruptured 48 hours prematurely. The mother had been started on amoxicillin and admitted to the maternity unit 24 hours after delivery. There was no outbreak of MRSA in the maternity unit at the time.
A conjunctival swab taken before antibiotic treatment grew MRSA. A repeat swab also grew MRSA which was sensitive to chloramphenicol. Further swabs grew MRSA from the nose and umbilicus. Both parents were doctors; one in hospital practice and the other in general practice. They were screened and found to be colonised with MRSA; the mother’s low vaginal swab and nasal swabs were positive as was the father’s nasal swab. The baby responded to chloramphenicol eye drops and the conjunctivitis resolved within a week. In addition, all three family members were treated with nasal mucopirocin and chlorhexidine skin wash. Post-treatment screening swabs showed the whole family was clear of MRSA.
The prevalence of MRSA carriage in healthcare workers has been reported at between 0% to 36%, depending on the specialty.2 The same study demonstrated a 40% transmission rate of MRSA from carrier healthcare workers to their households. Kniehl et al found that eradication of MRSA was more difficult to achieve where household contamination had occurred, possibly because of recolonisation of the healthcare worker. Eradication was defined as clear swabs at 3 months post-eradication therapy.3
Peacock et al4 prospectively looked at determinants of acquisition and carriage of Staphylococcus aureus in infancy. They found a 68% concordance for S aureus carriage between mothers and infants. The fact that the bacterial strains were often the same in mother-infant pairs led them to conclude that the mother is the usual source; the strain acquired is dictated by environmental factors. Similarly, the case described is likely to be the result of maternal transmission of MRSA manifesting as conjunctivitis—both parents were carriers, with maternal nasal and vaginal swab being MRSA positive. In addition, the infant was breast fed. These were some of the risk factors found by Peacock et al4 in determining infant carriage of MRSA. Bacterial typing of the MRSA strain was not available in this case.
In summary, MRSA conjunctivitis can be an additional cause for neonatal conjunctivitis. This case highlights the potential risk of healthcare workers transmitting disease to their households. Chloramphenicol eye drops have been reported to be effective in 81% of cases of MRSA conjunctivitis.5 However, strains resistant to chloramphenicol have been described. In addition topical chloramphenicol has been the subject of much discussion where concerns have been raised about its systemic side effects.6
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