Correspondence
The Possible Role of Circumcision in Newborn Outbreaks of Community-Associated Methicillin-Resistant Staphylococcal aureus
Clinical Pediatrics Volume 46 Number X Month 2007 1-3 © 2007 Sage Publications 10.1177/0009922806294847 http://clp.sagepub.com hosted at http://online.sagepub.com
Robert S. Van Howe, MD, MS, FAAP, and Wm. Lane M. Robson, MD, FRCPC, FRCP(Glasg) Outbreaks of community-associated methicillin-resistant Staphylococcus aureus were recently reported in newborns at 3 major urban centers. Boys were disproportionately infected. A literature review and a statistical analysis confirmed that male newborns are significantly more likely to
be infected with Staphylococcus aureus. Circumcision is a possible explanation for the recent outbreaks.
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male-to-female ratio is even higher in studies performed where most of the boys are circumcised as infants. When the study data in Table 13-11 are adjusted for the prevalence of circumcision using meta-regression,12 the summary odds ratio indicates that boys are still at greater risk (odds ratio, 1.40; 95% confidence interval, 1.24 to 1.59), and in communities in which circumcision is common, the risk for boys is doubled (odds ratio, 2.04; 95% confidence interval, 1.67 to 2.49). Several studies have directly compared the risk of colonization and infection with S aureus in boys by circumcision status (Table 2).13 When the study results are combined using meta-analysis techniques,14 circumcised boys are at an increased risk for staphylococcal colonization and infection. In a prospective study of colonization with S aureus and
recent issue of Morbidity and Mortality Weekly Report reports on 2 outbreaks of communityassociated methicillin-resistant Staphylococcus aureus (CA-MRSA) in 22 otherwise healthy newborns in Chicago and Los Angeles.1 The authors noted that 20 of the infants with CA-MRSA were boys. A similar study at Baylor College of Medicine in Houston found 61 cases of CA-MRSA and 28 cases of methicillin-sensitive S aureus in otherwise healthy term infants. Boys accounted for 73% of the cases.2 The authors of these studies did not offer any explanation or suggestion to explain the preponderance of affected male infants. A possible explanation is that most American males are circumcised before they leave the hospital. We reviewed the literature and identified 10 articles that reported on staphylococcal colonization and infection in the neonatal period. Male infants have a greater risk for staphylococcal colonization and infection than female infants (Table 1), and the
From Department of Pediatrics, Michigan State University College of Human Medicine Marquette, Michigan (RSVH), and The Childrens’ Clinic, Calgary, Alberta, Canada (WLMR). Address correspondence to: Robert S. Van Howe, MD, MS, 1414 W Fair Ave, Suite 226, Marquette, MI 49855; e-mail:
[email protected].
Keywords: community-associated methicillin-resistant Staphylococcus aureus; circumcision; neonatal infection
and pyoderma in newborn infants, all of the boys who were colonized and all of those with pyoderma were circumcised.6 In America, the distribution of sites for staphylococcal infection in the newborn period varies by sex. Girls present with predominantly conjunctival and facial lesions, and boys present with lesions in the groin, suprapubic area, and lower abdomen.1,5 This clinical distribution supports the possibility that the epicenter of the lesions in boys is the circumcision 1
2
Clinical Pediatrics / Vol. 46, No. X, Month 2007
Table 1.
Staphylococcal Lesions in Infants by Sex
Infected Infants
Healthy Infants
Study
Boys
Girls
Boys
Girls
OR
95% CI
Thompson3 Gooch4 Thompson5 Enzanauer6 Enzanauer7 Helms8 Williams9 Elias-Jones10 Plueckhahn11 Summary effect Adjusted summary effecta
363 54 198 9 33 525 46 108 1086
114 17 92 2 13 386 42 66 718
1651 4657 793 47 526 2778 209 709 6458
1675 4695 855 60 562 2626 192 668 6455
3.23 3.20 2.32 5.74 2.71 1.29 1.01 1.54 1.51 1.94 1.40
2.59-4.03 1.85-5.53 1.78-3.03 1.18-27.86 1.41-5.21 1.12-1.48 0.63-1.60 1.12-2.13 1.37-1.67 1.40-2.69 1.24-1.59
Country USA USA USA USA USA Denmark UK UK Australia
Note: OR = odds ratio; CI = confidence interval. a. Adjusted, using meta-regression, for circumcision prevalence.
Table 2.
Staphylococcal Lesions in Boys by Circumcision Status
Positive for lesions Study
Negative for lesions
Circed
Noncd
Circed
Noncd
OR
95% CI
Colonized Enzenauer7 Rush13 Summary effect
65 31
5 26
421 62
68 115
2.10 2.21 2.17
0.82-5.40 1.21-4.05 1.30-3.64
Infection Thompson3 Enzenauer7 Rush13 Summary effect
238 31 2
3 2 2
677 455 94
21 71 375
2.46 2.42 3.99 2.59
0.73-8.32 0.57-10.33 0.55-28.69 1.09-6.14
Note: Circed = circumcised; Noncd = not circumcised; OR = odds ratio; CI = confidence interval.
site. This possibility is also supported by a fluorescein powder study that showed that the circumcision room and circumcision equipment in the newborn nursery are a focal point for the spread of contamination.15 The likely scenario leading to the CA-MRSA outbreaks in Chicago, Los Angeles, and Houston is that the skin surface after birth is promptly colonized with hospital flora, which includes CA-MRSA. At the time of circumcision, the CA-MRSA gains access to the body when the mucosal and epidermal epithelial barriers are disrupted. Clinical evidence of the infection appears several days later. Newborn infection with CA-MRSA can lead to serious infections such as bacteremia, osteomyelitis, pyelonephritis, perinephric abscess, lung abscess, empyema, shock, and death.2
The prevention of S aureus infection in newborns has always been a challenge. Hexachlorophene baths were introduced in the 1960s, and although the prevalence of staphylococcal carriage and the number of staphylococcal infections in nurseries has decreased,16 outbreaks still occur. Control of CAMRSA with disinfectants in a hospital setting has become increasingly difficult.17 An impetigo outbreak that was caused by a resistant strain of S aureus in Kentucky in the early 1980s infected 20 infants, 17 of whom were boys. All but one was circumcised. Circumcisions were discontinued because the treating physicians believed that the circumcision site was particularly susceptible to bacterial growth.18 The American Academy of Pediatrics does not recommend routine circumcision of newborn males.19 Minimizing unnecessary newborn
Short Title / Van Howe et al
circumcisions might contribute to the efforts to control outbreaks of neonatal infection with CAMRSA and prevent the potentially serious morbid consequences.
References 1. Watson J, Jones RC, Cortes C, et al. Communityassociated methicillin-resistant Staphylococcal aureus infection among healthy newborns—Chicago and Los Angeles County, 2004. MMWR. 2006;55:329-332. 2. Fortunov RM, Hulten KG, Hammerman WA, Mason EO, Kaplan SL. Community-acquired Staphylococcus aureus infections in term and near term previously healthy neonates (Poster #2753.6). Poster presentation at: 2006 Pediatric Academic Societies’ Annual Meeting; April 26, 2006; San Francisco, Calif. 3. Thompson DJ, Gezon HM, Rogers KD, Yee RB, Hatch TF. Excess risk of staphylococcal infection and disease in newborn males. Am J Epidemiol. 1966;84:314-328. 4. Gooch JJ, Britt EM. Staphylococcus aureus colonization and infection in newborn nursery patients. Am J Dis Child. 1978;132:893-896. 5. Thompson DJ, Gezon HM, Hatch FF, Rycheck RR, Rogers KD. Sex distribution of Staphylococcus aureus colonization and disease in newborn infants. N Engl J Med. 1963;269:337-341. 6. Enzenauer RW, Dotson CR, Leonard T Jr, Brown J III, Pettett PG, Holton ME. Increased incidence of neonatal staphylococcal pyoderma in males. Mil Med. 1984; 149:408-410. 7. Enzenauer RW, Dotson CR, Leonard T, Reuben L, Bass JW, Brown J III. Male predominance in persistent staphylococcal colonization and infection of the newborn. Hawaii Med J. 1985;44:389-390, 392, 394-396. 8. Helms P, Stenderup A. Pyogenic infections in infants. Acta Obstetr Gynecol Scand. 1961;40:187-193.
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