Postpartum mastitis and community-acquired methicillin-resistant Staphylococcus aureus.This single-center, case-control study case-control study, n an investigation employing an epidemiologic approach in which previously existing incidents of a medical condition are used in lieu of gathering new information from a randomized population. documents a relative increase in methicillin resistance among 48 cases of Staphylococcus staphylococcus (stăf'ələkŏk`əs), any of the pathogenic bacteria, parasitic to humans, that belong to the genus Staphylococcus. The spherical bacterial cells (cocci) typically occur in irregular clusters [Gr. aureus--associated postpartum mastitis mastitis (măstī`tĭs), inflammation of the breast. Mastitis most commonly occurs in nursing mothers between the first and third weeks after childbirth, usually of the first child. during 1998-2005. Of 21 cases with methicillin resistance, 17 (81%) occurred in 2005. Twenty (95%) isolates contained the Staphylococcus cassette chromosome mec type IV gene; this suggests that the increase is due to community-acquired methicillin-resistant S.aureus The aureus (pl. aurei) was a gold coin of ancient Rome valued at 25 silver denarii. The aureus was regularly issued from the 1st century BC to the beginning of the 4th century AD, when it was replaced by the solidus. . ********** Postpartum mastitis (PPM) occurs in as many as one third of breastfeeding women in the United States and leads to breast abscess breast abscess Submammary abcess Gynecology An acute infection of the breast, which is particularly common during breast-feeding formation in [approximately equal to] 10% of cases (1,2). Although breast milk cultures are not routine in PPM management, the growth of potentially pathogenic bacteria Pathogenic bacteria Bacteria that produce illness. Mentioned in: Gastroenteritis (such as [beta]-hemolytic streptococci Streptococcus (plural, streptococci) A genus of spherical-shaped anaerobic bacteria occurring in pairs or chains. Sydenham's chorea is considered a complication of a streptococcal throat infection. or Staphylococcus aureus Staphylococcus au·re·us n. A bacterium that causes furunculosis, pyemia, osteomyelitis, suppuration of wounds, and food poisoning. Staphylococcus aureus Staphylococcus pyogenes ) is associated with longer time to recovery and more frequent abscess abscess, localized inflamation associated with tissue necrosis. Abscesses are characterized by inflamation, which is due to the accumulation of pus in the local tissues, and often painful swelling. formation (3). S. aureus is the most common bacterium isolated from such cultures, representing 37%-50% of isolates (4,5). Reports of methicillin-resistant S. aureus (MRSA MRSA Methicillin-resistant Staphylococcus aureus. See MARSA. ) PPM among young, healthy women lacking traditional risk factors for MRSA have emerged in the past few years (6, 7). Isolates in these cases of community-acquired infection (CA-MRSA CA-MRSA Community Acquired Methicillin-Resistant Staphylococcus Aureus ) remain susceptible to multiple non--[beta]-lactam antibiotics and possess distinct molecular features (8). Although risk factors associated with skin and soft tissue infections due to CA-MRSA have been described (8,9), characteristics unique to patients with CA-MRSA PPM are unknown. To identify risk factors, complications, and outcomes among patients with CA-MRSA PPM, we conducted a retrospective, case-control study to include all S. aureus-associated cases at a single institution over an 8-year period. MRSA isolates were analyzed by PCR PCR polymerase chain reaction. PCR abbr. polymerase chain reaction Polymerase chain reaction (PCR) for the presence of the Staphylococcus cassette chromosome (SCC SCC - strongly connected component ) mec type IV gene, which is commonly associated with community-acquired infection. The Study We considered for analysis all patients from Northwestern University's Prentice Women's Hospital and affiliated Lynn Sage Comprehensive Breast Center with wound, fluid, drainage, or breast milk cultures positive for S. aureus from January 1998 through December 2005. Case-patients were defined as patients with PPM and a corresponding culture positive for MRSA. Control-patients were defined as patients with PPM and a corresponding culture positive for methicillin-susceptible S. attreus (MSSA MSSA Methicillin-Sensitive Staphylococcus Aureus MSSA Microscopy Society of Southern Africa MSSA Maryland Saltwater Sportfishermen's Association MSSA Military Selective Service Act MSSA Mid-South Sociological Association MSSA Minnesota Social Service Association ). Patients who had no evidence of mastitis or who had a history of MRSA were excluded from the study. SCCmec types I-V I-V Current/Voltage were identified by a PCR-based multiplex assay; rapid bacterial DNA extraction and PCR amplification were performed as described elsewhere (10). Forty-eight cases of S. aureus-associated PPM were identified during the study period; 21 cases were due to MRSA and 27 cases were due to MSSA. A relative increase in MRSA PPM was noted in the later years of the study (Figure 1, p = 0.04). MRSA and MSSA patients did not differ significantly with respect to age, pregnancy history, or symptoms at the time of initial evaluation. In addition, MRSA and MSSA patients did not differ in terms of potential risk factors for infection, such as diabetes, group B [beta]-hemolytic streptococcus streptococcus (strĕp'təkŏk`əs), any of a group of gram-positive bacteria, genus Streptococcus, some of which cause disease. colonization, artificial rupture of membranes Rupture of membranes (ROM) is a term used during pregnancy to describe a rupture of the amniotic sac at the onset of, or during, labor. This is colloquially known as "breaking water". , epidural anesthesia epidural anesthesia n. Regional anesthesia produced by injection of a local anesthetic into the epidural space of the lumbar or sacral region of the spine. , vaginal lacerations, episiotomy Episiotomy Definition An episiotomy is a surgical incision made in the area between the vagina and anus (perineum). This is done during the last stages of labor and delivery to expand the opening of the vagina to prevent tearing during the delivery of , cesarean section cesarean section (sĭzâr`ēən), delivery of an infant by surgical removal from the uterus through an abdominal incision. The operation is of ancient origin: indeed, the name derives from the legend that Julius Caesar was born in this , or intrapartum antibiotic use (Table). [FIGURE 1 OMITTED] Ten (48%) MRSA and 11 (41%) MSSA patients required hospitalization. Although these inpatients did not differ in duration of symptoms before admission, length of stay, or leukocyte count leukocyte count see White cell count , MRSA patients were more likely to have fever. One patient in each group required readmission readmission Managed care The admission of a Pt to a health care facility for a condition–eg, stroke, MI, GI bleeding, hip fracture, cancer surgery, shortly after discharge. See nth admission. Cf Admission, Discharge. for recurrent symptoms (Table). Forty-six study patients had an abscess associated with mastitis; most (39 patients) underwent needle aspiration. Of these patients, 7 (41%) MRSA and 5 (23%) MSSA patients required repeat aspiration. Notably, 9 MSSA patients underwent incision and drainage Incision and drainage is a minor surgical procedure to release pus or pressure built up under the skin, such as from an abscess or boil. It is performed by treating the area with an antiseptic, such as iodine based solution, and then making a small incision to puncture the skin a median of 4.5 days after aspiration (range 0-17 days), whereas only 1 MRSA patient required subsequent debridement Debridement Definition Debridement is the process of removing nonliving tissue from pressure ulcers, burns, and other wounds. Purpose Debridement speeds the healing of pressure ulcers, burns, and other wounds. (1 day later). Reasons for this difference are not clear; however, the more frequent use of serial ultrasound-guided aspiration in breast abscess management in recent years (when most MRSA cases occurred) may account for this finding. In 17 of 21 MRSA cases, antibiotic use was documented. Twelve patients received antibiotics effective against MRSA, but only 2 received effective coverage at therapy onset (both received clindamycin). Patients initially received a penicillinase-resistant penicillin (10 patients), a first-generation cephalosporin cephalosporin (sĕf'əlōspôr`ĭn), any of a group of more than 20 antibiotics derived from species of fungi of the genus Cephalosporium and closely related chemically to penicillin. Cephalosporins, e.g. (3 patients), a [beta]-lactam/[beta]-lactamase inhibitor (1 patient), or some combination of the above (6 patients). Median time to effective coverage for MRSA was 5 days (range 0-16 days); adequate antimicrobial agents included vancomycin (4 patients), trimethoprim-sulfamethoxazole (1 patient), clindamycin (9 patients), rifampin rifampin (rĭfăm`pĭn), antibiotic used in the treatment of tuberculosis. It is also used to eliminate the meningococcus microorganism from carriers and to treat leprosy, or Hansen's disease. (2 patients), or some combination of the above (4 patients). Median duration of therapy, documented in 8 of 12 effective regimens, was 19 days (range 14-62 days). Antimicrobial agent use was documented for 18 of 27 MSSA cases; in all 18 cases, isolates were susceptible to the initial antibiotic of choice. Initial regimens included penicillinase-resistant penicillins (10 patients), first-generation cephalosporins Cephalosporins Definition Cephalosporins are medicines that kill bacteria or prevent their growth. Purpose Cephalosporins are used to treat infections in different parts of the body—the ears, nose, throat, lungs, sinuses, and (2 patients), macrolides (1 patient), tetracyclines Tetracyclines Definition Tetracyclines are medicines that kill certain infection-causing microorganisms. Purpose Tetracyclines are called "broad-spectrum" antibiotics, because they can be used to treat a wide variety of (1 patient), [beta]-lactam/[beta]-lactamase inhibitors (1 patient), vancomycin (1 patient), and clindamycin (2 patients). Duration of therapy for MSSA PPM, documented in 12 of 18 cases, was a median of 13.5 days (range 9-27 days). Medical record review of affected patients did not show transmission of S. aureus to infants or other family members. In 1 MRSA patient, a perirectal abscess developed 5 months after the mastitis resolved. Intraoperative cultures of the abscess grew MRSA with identical susceptibilities, which suggests persistent colonization; however, typing of the isolates was not performed. Of 21 MRSA isolates available for PCR analysis, 20 possessed SCCmec IV. The remaining isolate contained SCCmec II (Figure 2) and displayed resistance to clindamycin. In contrast, 95% of isolates with SCC mec IV were clindamycin susceptible. [FIGURE 2 OMITTED] Conclusions To our knowledge, this is the largest case-control study of patients with MRSA-associated PPM. Although S. aureus is the most common etiologic agent of PPM, cases caused by MRSA have rarely been described. Epidemic MRSA cases, linked to the hospital transmission of a community-acquired isolate, have been observed more recently (6). Our study suggests that CA-MRSA is an increasingly common pathogen in spontaneous cases of PPM. PPM due to CA-MRSA appears to be increasing at our institution. Among 17 MRSA-infected mothers in 2005, delivery dates spanned >9 months without overlap, which suggests that MRSA was independently acquired rather than outbreak-related. In addition, although isolates were not subjected to molecular typing by pulsed-field gel electrophoresis, PCR results suggest that 16 (94%) of MRSA isolates in 2005 were community-acquired. The epidemiology of CA-MRSA PPM is poorly understood. Notably, nearly twice as many MRSA-infected than MSSA-infected women were multiparous mul·tip·a·rous adj. 1. Relating to a multipara. 2. Giving birth to more than one offspring at a time. in this study (57% vs. 33%, respectively). The prevalence of CAMRSA is increasing among young children, and intrafamilial transmission of isolates has been documented (11,12). Therefore, mothers with young children may be at increased risk for CA-MRSA PPM. Alternatively, these patients may serve as a reservoir for MRSA in the community, transmitting this organism to family members. In the current study, women with MRSA were significantly less likely to receive adequate and timely antimicrobial drug treatment, but consequences of this difference are unclear. Lee et al. suggest that small CA-MRSA abscesses in children can be managed effectively with incision and drainage alone (13). Indeed, most women in this study underwent incision and drainage or wound aspiration without significant differences in outcomes. Although MSSA patients were more likely to undergo breast abscess incision and drainage than their MRSA counterparts, both methods are considered appropriate surgical interventions (14). Although related cases of infant infection were not found, charts of household contacts were not reviewed in this study; cases of S. aureus transmission to infants or other family members may have been undetected. Several authors have reported mother-to-infant transmission of MRSA through breast milk (15,16). Although decolonization decolonization Process by which colonies become independent of the colonizing country. Decolonization was gradual and peaceful for some British colonies largely settled by expatriates but violent for others, where native rebellions were energized by nationalism. measures in MRSA-colonized patients have not demonstrated long-term effectiveness (17), the possibility of infant MRSA acquisition may warrant further evaluation of such measures in infected, breastfeeding mothers. As with any retrospective case-control study, ours had several limitations. First, the study population is small, which limits the generalizability of the results. Second, patients were added to the study by using results of positive cultures; consequently, cases likely represented more severe and complicated infections in which cultures were necessary after routine therapeutic measures failed. Third, although PPM has been associated with multiple patient factors (i.e., difficulty breastfeeding, tobacco use, and stress), a thorough risk assessment is limited by retrospective study retrospective study, a study in which a search is made for a relationship between one phenomenon or condition and another that occurred in the past (e.g. . In addition, medical record review may not indicate certain CA-MRSA risk factors, such as socioeconomic status socioeconomic status, n the position of an individual on a socio-economic scale that measures such factors as education, income, type of occupation, place of residence, and in some populations, ethnicity and religion. , history of incarceration Confinement in a jail or prison; imprisonment. Police officers and other law enforcement officers are authorized by federal, state, and local lawmakers to arrest and confine persons suspected of crimes. The judicial system is authorized to confine persons convicted of crimes. , or exposure to day care facilities. Finally, although the study results suggest a recent increase in MRSA PPM, an assessment of incidence would require further prospective analysis. In summary, CA-MRSA has emerged as an increasingly common pathogen in PPM. Therapy against CAMRSA should be considered in refractory or severe cases of PPM until wound, drainage, or breast milk cultures can be obtained. Adjunct surgical drainage or aspiration is often warranted in such cases. Additional study is required to determine the utility of routine cultures in postpartum mastitis, the prevalence of CA-MRSA in this emerging problem, and the consequences of CA-MRSA colonization for breastfeeding infants. Acknowledgments MSSA and MRSA isolates were identified from the microbiology database by Mike Malczynski. MRSA strains used as controls for SCCmec typing, including type I (NCTC NCTC National Conservation Training Center NCTC National Counterterrorism Center (9/11 Commission Report) NCTC National Cable Television Cooperative NCTC National Collection of Type Cultures (UK laboratory) 10442), type II (N315), type III (85/2082), type IV (CA05), and type V (WIS [WBG WBG World Bank Group WBG Wide Bandgap WBG Wales Biodiversity Group WBG Wide-Band Gaussian 8318]-JCSC3624), were kindly provided by Dr Teruyo Ito. We also thank Dr Patricia Garcia for her support and guidance. References (1.) Barbosa-Cesnik C, Schwartz K, Foxman B. Lactation lactation Production of milk by female mammals after giving birth. The milk is discharged by the mammary glands in the breasts. Hormones triggered by delivery of the placenta and by nursing stimulate milk production. mastitis. JAMA JAMA abbr. Journal of the American Medical Association . 2003;289:1609-13. (2.) Foxman B, D'Arcy H, Gillespie B, Bobo JK, Schwartz K. Lactation mastitis: occurrence and medical management among 946 breastfeeding women in the United States. Am J Epidemiol. 2002; 155:103-14. (3.) Osterman KL, Rahm VA. Lactation mastitis: bacterial cultivation of breast milk, symptoms, treatment, and outcome. J Hum Lact. 2000;16:297-302. (4.) Marshall BR, Hepper JK, Zirbel CC. Sporadic puerperal puerperal /pu·er·per·al/ (-al) pertaining to a puerpera or to the puerperium. pu·er·per·al adj. mastitis: an infection that need not interrupt lactation. JAMA. 1975;233:1377-9. (5.) Niebyl JR, Spence MR, Parmley TH. Sporadic (non-epidemic) puerperal mastitis. J Reprod Med. 1978;20:97-100. (6.) Saiman L, O'Keefe M, Graham PL III, Wu F, Said-Salim B, Kreiswirth B, et el. Hospital transmission of community-acquired methicillin-resistant Staphylococcus aureus methicillin-resistant Staphylococcus aureus Methicillin-aminoglycoside resistant Staphylococcus aureus, MRSA An organism with multiple antibiotic resistances–eg, aminoglycosides, chloramphenicol, clindamycin, erythromycin, rifampin, tetracycline, among postpartum women. Clin Infect Dis. 2003;37:1313-9. (7.) Laibl VR, Sheffield JS, Roberts S, McIntire DD, Trevino S, Wendel GD Jr. Clinical presentation of community-acquired methicillin-resistant Staphylococcus aureus in pregnancy. Obstet Gyneeol. 2005;106:461-5. (8.) Naimi TS, LeDell KH, Como-Sabetti K, Borchardt SM, Boxrud D J, Etienne J, et el. Comparison of community- and health care-associated methicillin-resistant Staphylococcus aureus infection. JAMA. 2003;290:2976-84. (9.) Charlebois ED, Perdreau-Remington F, Kreiswirth B, Bangsberg DR, Ciccarone D, Diep BA, et el. Origins of community strains of methicillin-resistant Staphylococcus aureus. Clin Infect Dis. 2004;39:47-54. (10.) Zhang K, McClure J, Elsayed S, Louie T, Conly JM. Novel multiplex PCR assay for characterization and concomitant subtyping of Staphylococcal staphylococcal pertaining to Staphylococcus spp. staphylococcal clumping test used as a means of measuring the quantity of fibrinogen-split products in a sample of blood. cassette chromosome mec types I to IV in methicillin-resistant Staphylococcus aureus. J Clin Mierobiol. 2005;43:5026-33. (11.) Herold BC, Immergluck LC, Maranan MC, Lauderdale DS, Gaskin gaskin the muscular portion of the hindleg between the stifle and hock, corresponding to the human calf. The term is used in horses and sometimes dogs. RE, Boyle-Vavra S, et el. Community-acquired methicillin-resistant Staphylococcus aureus in children with no identified predisposed risk. JAMA. 1998;279:593-8. (12.) Jones TF, Creech CB, Erwin P, Baird SG, Woron AM, Sehaffner W. Family outbreaks of invasive community-associated methicillin-resistant Staphylococcus aureus infection [cited 2006 Dee 26]. Clin Infect Dis [serial online]. 2006 Mar. Available from http://www.journals.uchicago.edu/CID/journal/issues/v42n9/38813 /38813.web.pdf (13.) Lee MC, Rios AM, Aten MF, Mejias A, Cavuoti D, McCracken GH Jr, et el. Management and outcome of children with skin and soft tissue abscesses caused by community-acquired methicillin-resistant Staphylococcus aureus. Pediatr Infect Dis J. 2004;23:123-7. (14.) Dener C, Inan A. Breast abscesses in lactating lac·tate 1 intr.v. lac·tat·ed, lac·tat·ing, lac·tates To secrete or produce milk. [Latin lact women. World J Surg. 2003;27:130-3. (15.) Kawada M, Okuzumi K, Hitomi S, Sugishita C. Transmission of Staphylococcus aureus between healthy, lactating mothers and their infants by breastfeeding. J Hum Lact. 2003;19:411-7. (16.) Behari P, Englund J, Alcasid G, Garcia-Houchins S, Weber SG. Transmission of methicillin-resistant Staphylococcus aureus to preterm infants through breast milk. Infect Control Hosp Epidemiol. 2004;25:778-80. (17.) Loveday HP, Pellowe CM, Jones SR, Pratt RJ. A systematic review of the evidence for interventions for the prevention and control of methicillin-resistant Staphylococcus aureus (1996-2004): report to the Joint MRSA Working Party (Subgroup A). J Hosp Infect. 2006;63(Suppl 1):S45-70. Address for correspondence: Pavani Reddy, Division of Infectious Diseases, Northwestern University Feinberg School of Medicine The Feinberg School of Medicine is one of Northwestern University's 11 schools and colleges. It is a prestigious American medical school located in the Streeterville neighborhood of Chicago, Illinois, situated near Lake Michigan and the Magnificent Mile. , 676 N Saint Clair St, Suite 200, Chicago, IL 60611, USA; email: preddy2@md.northwestern.edu Pavani Reddy, * Chao Qi,* Teresa Zembower, * Gary A. Noskin, * and Maureen Bolon * * Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA Dr Reddy is currently a fellow in the Division of Infectious Diseases at Northwestern University Feinberg School of Medicine. Her research and clinical interests include surgery-related infections and multidrug-resistant, nosocomial nosocomial /noso·co·mi·al/ (nos?o-ko´me-il) pertaining to or originating in a hospital. nos·o·co·mi·al adj. 1. Of or relating to a hospital. 2. pathogens.
Table. Demographics, symptoms, interventions, and outcomes in
patients with Staphylococcus aureus-associated postpartum mastitis *
No. (%) patients
Variable MRSA (n = 21) MSSA (n = 27)
Demographics
Median age, y 32 32.5
Multiparous 12 (57) 9 (33)
Race ([dagger])
Caucasian 15 (71) 19 (79)
Other 6 (29) 5 (21)
Clinical symptoms
Fever 7 (33) 10 (37)
Skin changes or fissures 6 (29) 8 (30)
Induration 20 (95) 21 (78)
Median time from delivery
to symptom onset, d 27 33.5
Prenatal risk factors
Diabetes 2 (10) 1 (4)
Group B [beta]-hemolytic
streptococcus colonization
([double dagger]) 3 (16) 4 (16)
Intrapartum risk factors
Intrapartum treatment with
antimicrobial drugs ([dagger]) 9 (43) 7 (29)
Cesarean section
([double dagger]) 3 (14) 2 (8)
Artificial rupture of
membranes ([section]) 12 (63) 10 (44)
Vaginal laceration or
episiotomy ([section]) 18 (95) 22 (82)
Epidural anesthesia ([section]) 12 (63) 18 (78)
Interventions
Aspiration 17 (81) 22 (82)
Repeat aspiration 7 (41) 5 (23)
Incision and drainage 1 (6) 9 (41)
Drain placement 3 (14) 6 (22)
Outcomes
Hospital admission 10 11
Median length of stay, d 4 4
Median leukocyte count,
cells/[micro]L 12.8 15.3
Temperature >38.1 [degrees]C 6 (60) 2 (18)
Recurrent symptoms requiring
readmission 1 (10) 1 (9)
Outpatient, later admitted 2 (18) 1 (6)
Breastfeeding discontinued
([paragraph]) 3 (16) 5 (22)
Variable OR (95% CI) p value *
Demographics
Median age, y -- 0.90
Multiparous 2.67 (0.71-10.4) 0.10
Race ([dagger])
Caucasian 0.66 (0.13-3.19) 0.55
Other 1.52 (0.31-7.59) 0.55
Clinical symptoms
Fever 0.85 (0.22-3.30) 0.79
Skin changes or fissures 0.95 (0.23-3.96) 0.94
Induration 5.71 (0.59-275.7) 0.09
Median time from delivery
to symptom onset, d -- 0.6
Prenatal risk factors
Diabetes 2.74 (0.13-167.56) 0.41
Group B [beta]-hemolytic
streptococcus colonization
([double dagger]) 0.88 (0.11-5.96) 0.87
Intrapartum risk factors
Intrapartum treatment with
antimicrobial drugs ([dagger]) 1.82 (0.45-7.52) 0.34
Cesarean section
([double dagger]) 1.92 (0.19-24.89) 0.50
Artificial rupture of
membranes ([section]) 2.23 (0.54-9.41) 0.20
Vaginal laceration or
episiotomy ([section]) 0.82 (0.01-67.75) 0.89
Epidural anesthesia ([section]) 0.48 (0.10-2.26) 0.28
Interventions
Aspiration 0.97 (0.18-5.66) 0.96
Repeat aspiration 2.38 (0.48-12.14) 0.22
Incision and drainage 0.09 (0.00-0.84) 0.01
Drain placement 0.58 (0.08-3.26) 0.49
Outcomes
Hospital admission 1.32 (0.36-4.90) 0.63
Median length of stay, d -- 0.90
Median leukocyte count,
cells/[micro]L -- 0.21
Temperature >38.1 [degrees]C 6.75 (0.69-88.48) 0.05
Recurrent symptoms requiring
readmission 1.11 (0.01-95.83) 0.94
Outpatient, later admitted 3.75 (0.16-235.66) 0.29
Breastfeeding discontinued
([paragraph]) 0.71 (0.10-4.38) 0.67
* MRSA, methicillin-resistant Staphylococcus aureus; MSSA,
methicillin-susceptible S. aureus; OR, odds ratio for categorical
variables using [chi square] analysis or Fisher exact test where
appropriate, CI, confidence interval; p values for continuous variables
calculated by using the Wilcoxon test.
([dagger]) Data available for 25 MSSA patients.
([double dagger]) Data available for 24 MSSA patients.
([section]) Data available for 19 MRSA and 23 MSSA patients.
([paragraph]) Data available for 19 MRSA and 24 MSSA patients.
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