Importance of asymptomatic shedding of Clostridium difficile in environmental contamination of a neonatal intensive care unit.

A survey of C. difficle in a neonatal intensive care unit (NICU) was conducted. Approximately 25% of infants in the NICU were colonized with Clostridium difficle. Environmental surface cultures were obtained from the NICU and compared with cultures taken from infant, adolescent, and hematology/oncology units. From 150 surface cultures, C difficle was recovered exclusively from the NICU. Of the 16 different types of surfaces cultured, diaper scales and the surrounding area were contaminated most often at 50%.

Further observations on the role of Staphylococcus aureus exotoxins and IgE in the pathogenesis of nasal polyposis.

OBJECTIVES/HYPOTHESIS: Recent studies have suggested that Staphylococcus aureus secrete exotoxins that may act as superantigens and upregulate the variable beta region of lymphocytes in chronic hyperplasticsinusitis with nasal polyposis (CHSwNP). The aim of this study was to add further information for correlating the presence of staphylococcal species and the upregulation of the V(ß) region of both nasal polyp lymphocytes and peripheral blood lymphocytes. Furthermore, IgE-mediated hypersensitivity directed against these exotoxins produces an additional independent immunologic mechanism in upregulating the inflammatory response in the lateral wall of the nose in nasal polyposis. STUDY DESIGN: Prospective study. METHODS: Nasal polyps were harvested from 38 patients with CHSwNP. Eleven patients were studied for the correlation of exotoxin from staphylococcal species and the variable beta region of lymphocytes in both the nasal polyp lymphocytes and corresponding peripheral blood lymphocytes. Eight additional patients with CHSwNP were studied for local and systemic IgE-mediated immunity directed against S aureus exotoxins. Flow cytometry was used to analyze the V(ß) repertoire of polyp-derived CD3-positive lymphocytes from 11 patients. S aureus was isolated from nine patients, and coagulase-negative Staphylococcus was isolated from two patients in whom at least 1 × 10(6) T cells could be isolated from their nasal polyps. A quantitative assay for IgE was developed to study the levels of this immunoglobulin directed against S aureus exotoxins in both the nasal polyp and the peripheral blood lymphocytes of 11 patients and in the nasal mucus and serum of eight additional patients. RESULTS: Eleven patients had T-cell V(ß) clonal expansion. S aureus exotoxin upregulated the corresponding V(ß) region of lymphocytes in both the nasal polyp T cells as well as the T cells from the peripheral blood in nine patients, and two patients with coagulase-negative Staphylococcus also demonstrated upregulation of the V(ß) region in the nasal polyps in the absence of exotoxins. In one patient, in vivo exotoxin was isolated, which correlated with the in vitro isolation from the organism itself. IgE directed against staphylococcal enterotoxin B (SEB) and toxic shock syndrome toxin was significantly elevated in the sera of patients with CHSwNP (P < .0001) as compared with the sera of age-related healthy control subjects; IgE directed against staphylococcal enterotoxin A and SEB (P = .0047) was significantly elevated in the mucus of eight patients with CHSwNP as compared with the nasal mucus of healthy controls. CONCLUSIONS: This study augments our understanding of the potential role of S aureus exotoxins behaving as superantigens in the lateral wall of the nose in CHSwNP. Furthermore, local nasal IgE directed against these exotoxins may create a local allergic inflammation in the lateral wall of the nose. These two immunologic mechanisms are independent but may be additive in the inflammatory process in CHSwNP.

Staphylococcus aureus antimicrobial susceptibility of abscess samples from adults and children from the Kaleida Health System in western New York State, 2003 to 2006.

Staphylococcus aureus is the most common etiologic agent of skin abscesses. The regional rate of methicillin-resistant S. aureus (MRSA) abscesses may reflect the prevalence of local community-acquired MRSA (CAMRSA). A retrospective study was conducted to compare the antimicrobial susceptibility patterns of S. aureus isolates recovered from abscesses from 2003 to 2006 from patients at hospitals of the Kaleida Health System in western New York. S. aureus susceptibility information was obtained from a Vitek Legacy system, and the location and source of each isolate were identified. EpiInfo software was used to analyze the antimicrobial susceptibilities of all isolates and the trends in the rates of MRSA. A total of 2,848 S. aureus abscesses were identified by the Kaleida Health Clinical Microbiology Laboratory. Of those, 978 S. aureus abscess events occurred in four hospitals, including three adult facilities (547 episodes with 62 cases of bacteremia) and one children's facility (431 episodes with 2 cases of bacteremia). The MRSA rates in adults increased from 56% (2003) to 71% (2006), and that in children increased from 26% (2003) to 64% (2006). Of the MRSA isolates in the children's samples, more than 92% were susceptible to clindamycin. Of the MRSA isolates in the adult samples, 50% were susceptible to clindamycin in 2003 and 2004, whereas greater than 75% were susceptible in 2005 and 2006. The increased rates of MRSA abscesses with susceptibility to clindamycin may reflect the high prevalence level of CAMRSA in the western New York community. The variations in S. aureus susceptibilities could serve as an indicator of the changing resistance patterns within a broad urban community.

Importance of colonization site in the current epidemic of staphylococcal skin abscesses.

OBJECTIVE: The goal was to compare rectal and nasal Staphylococcus aureus colonization rates and S aureus pulsed-field types (PFTs) for children with S aureus skin and soft-tissue abscesses and normal control subjects. METHODS: Sixty consecutive children with S aureus skin and soft-tissue abscesses that required surgical drainage and 90 control subjects were enrolled. Cultures of the nares and rectum were taken in both groups. S aureus isolates from all sites were characterized through multiple-locus, variable-number, tandem-repeat analysis, pulsed-field gel electrophoresis, staphylococcal cassette chromosome mec typing for methicillin-resistant S aureus isolates, and determination of the presence of Panton-Valentine leukocidin genes. RESULTS: S aureus was detected significantly more often in the rectum of children with abscesses (47%) compared with those in the control group (1%; P = .0001). Rates of nasal colonization with S aureus were equivalent for children with abscesses (27%) and control subjects (20%; P = .33). S aureus recovered from the rectum was identical to S aureus in the abscess in 88% of cases, compared with 75% of nasal isolates. PFT USA300, staphylococcal cassette chromosome mec type IV, and Panton-Valentine leukocidin genes were significantly increased in the S aureus isolates from children with abscesses compared with those from control subjects. CONCLUSIONS: Skin and soft-tissue abscesses in the current epidemic of community-associated staphylococcal disease are strongly associated with rectal colonization by PFT USA300. Nasal colonization in children does not seem to be a risk factor.

Clinical and molecular characteristics of staphylococcal skin abscesses in children.

Forty-nine children with skin abscesses (36 methicillin-resistant Staphylococcus aureus and 13 methicillin-susceptible S. aureus) exhibited similar disease severity. Both pathogen groups were pulse field type USA300, multilocus sequence type 8, and possessed Panton-Valentine leukocidin genes. Related microbial genetic architecture may account for similarities in disease severity despite differences in antibiotic susceptibility.

Bacterial interference of penicillin-sensitive and -resistant Streptococcus pneumoniae by Streptococcus oralis in an adenoid organ culture: implications for the treatment of recurrent upper respiratory tract infections in children and adults.

OBJECTIVES: The role of the viridans group of streptococci (Streptococcus oralis) in the prevention of colonization with Streptococcus pneumoniae was investigated in an adenoid organ culture system. METHODS: The adenoids from 10 patients who were undergoing adenoidectomy for either hypertrophy or recurrent otitis media were used. RESULTS: Streptococcus oralis Parker and S. oralis Booth (two organisms isolated from the nasopharynges of patients undergoing adenoidectomy only and patients undergoing adenoidectomy and bilateral tympanostomy with tubes, respectively) uniformly inhibited both penicillin-sensitive and penicillin-resistant S. pneumoniae. Although both strains of S. oralis inhibited the growth of both S. pneumoniae strains, strain Parker provided more complete inhibition than did strain Booth. CONCLUSIONS: The results indicate that some strains of S. oralis may inhibit the growth of the most serious pathogens in the nasopharynx. It is therefore possible that colonization of inhibitory strains of viridans streptococci may be used in the nasopharynx as a relatively safe and inexpensive approach to prevention of recurrent otitis media in some children and of recurrent suppurative sinusitis in both children and adults.

Low prevalence of Listeria monocytogenes in human stool.

Listeria monocytogenes is a foodborne pathogen that is found widely in the environment and in a variety of ready-to-eat foods, yet human invasive infection is relatively rare (five cases per million people annually in the United States). Despite wide exposure to this organism, little is known about the prevalence of L. monocytogenes in human stool, and it is not known whether human fecal dispersal contributes to human foodborne transmission. We cultured 827 stool specimens (well formed and loose-watery) from individuals from four large metropolitan areas of New York state for L. monocytogenes and found only 1 (0.12%) positive specimen. L. monocytogenes was also isolated from the blood of the person with the single positive specimen, and the two isolates were indistinguishable by molecular subtyping (both were ribotype DUP-1042B). This provides further evidence that human L. monocytogenes fecal carriage among persons with and without diarrheal disease is remarkably low. Unlike the case for other foodborne pathogens (e.g., Salmonella), human shedders probably do not contribute significantly to L. monocytogenes contamination of foods. However, we observed a single individual with invasive listeriosis that shed the pathogen in feces, indicating the potential for fecal dispersal of L. monocytogenes from persons with listeriosis.

In vivo effects of bifidobacteria and lactoferrin on gut endotoxin concentration and mucosal immunity in Balb/c mice.

The aim of the present study was to examine the effects of oral supplementation of newborn Balb/c mice with bifidobacteria (B. infantis, B. bifidum) and iron-free apo-lactoferrin (bovine, human) on gut endotoxin concentration and mucosal immunity. Endotoxin concentration was measured in ileocecal filtrates at 7, 14, 21, and 28 days postdelivery by a quantitative limulus amebocyte lysate test. While endotoxin levels in bifidobacteria-fed mice showed a steady rise over time, they were consistently lower than that observed in control animals. Results of lactoferrin supplementation varied depending on the specific time point, but overall by day 28, all treatment groups showed lower intestinal endotoxin concentrations compared to saline fed animals. Neither bifidobacteria nor lactoferrin stimulated an increase in B or T cells, or in cytokine production (IL-6, TNF-alpha, INF-gamma), in Peyer's patches as measured by flow cytometry. Bifidobacteria and lactoferrin were well tolerated as dietary supplements and showed promising potential to reduce gut endotoxin levels.

In vitro growth responses of bifidobacteria and enteropathogens to bovine and human lactoferrin.

A series of in vitro experiments was performed to test the ability of bovine and human lactoferrin to influence the growth of the gram-positive probiotic bacteria, Bifidobacterium bifidum, Bifidobacterium infantis, and Lactobacillus acidophilus, as well as the gram-negative enteric bacteria, E. coli O157:H7 and Salmonella typhimurium. None of the lactoferrin preparations stimulated the growth of the tested strains. However, iron-free apo-lactoferrin (bovine and human) and 66% iron-saturated bovine lactoferrin dramatically slowed the growth of E. coli O157:H7 in single culture experiments, while 98% iron-saturated preparations had no effect. In coculture experiments of B. infantis and E. coli, the iron-limited preparations of lactoferrin also slowed the growth of the latter without inhibiting the bifidobacteria. These results suggest that lactoferrin in iron-limited forms may have the potential to be combined with probiotic bacteria in biotherapeutic products, which could help balance human gut microflora and limit the overgrowth of certain enteric microorganisms.

A superantigen hypothesis for the pathogenesis of chronic hyperplastic sinusitis with massive nasal polyposis.

BACKGROUND: The pathogenesis of chronic hyperplastic sinusitis with massive nasal polyposis is still an enigma; however, the molecular biology of this disease is beginning to become unraveled and the proinflammatory cytokines and the message and the product of these cytokines have all been identified in nasal polyps. However, the initial trigger that causes inflammation of the lateral wall of the nose to up-regulate lymphocytes and eosinophils is still unknown. METHODS: Thirteen patients with massive polyposis were studied. The mucus of the nasal cavities surrounding the nasal polyps was studied for both bacterial and fungal species. The lymphocytes of the nasal polyps were extracted and evaluated for the T-cell receptor, particularly, the variable beta region of this receptor. Enterotoxins (superantigens) of the bacteria were studied. Finally, the histopathology of nasal polyps was studied. RESULTS: Fifty-five percent of the patients had toxin-producing Staphylococcus aureus in the nasal mucus adjacent to the polyps. Three different enterotoxins were isolated, including Staphylococcus enterotoxin A, Staphylococcus enterotoxin B, and toxic shock syndrome toxin 1. The variable B specificity for these superantigens was identified also in the polyp lymphocyte T-cell receptor. CONCLUSION: A superantigen hypothesis for massive polyposis is suggested because the most common bacterial species found in the nasal mucus is Staphylococcus aureus. These bacteria produce enterotoxins in all of the cases studied and the corresponding variable beta region of the T-cell receptor also was up-regulated in the polyp lymphocytes in cases studied thus far. These data taken together suggest that the initial injury to the lateral wall of the nose may be the result of toxin-producing Staphylococci. Superantigens (enterotoxins) may up-regulate lymphocytes to produce cytokines that are responsible for the massive up-regulation of lymphocytes, eosinophils, and macrophages, the three most common inflammatory cells found in massive nasal polyposis.

Interference of nontypeable Haemophilus influenzae and Moraxella catarrhalis by Streptococcus oralis in adenoid organ culture: a possible strategy for the treatment of the otitis-prone child.

The role of viridans group streptococci (Streptococcus oralis) in the prevention of colonization with nontypeable Haemophilus influenzae and Moraxella catarrhalis was investigated in an adenoid organ culture system. The adenoids from 100 patients who were undergoing adenoidectomy for either hypertrophy or recurrent otitis media were used. Streptococcus oralis Parker uniformly inhibited colonization with nontypeable H. influenzae or M. catarrhalis over a 24-hour period of incubation in adenoid organ culture. Streptococcus oralis Booth, a noninhibitory strain, did not significantly reduce colonization with nontypeable H. influenzae and M. catarrhalis. The results indicate that some strains of S. oralis may inhibit colonization with potential pathogens in the nasopharynx. It is therefore possible that colonization with inhibitory strains of viridans streptococci may be used in the nasopharynx as a relatively safe and inexpensive approach to prevention of recurrent otitis media in some children.

Immune responses in rhesus rotavirus-challenged BALB/c mice treated with bifidobacteria and prebiotic supplements.

Bifidobacterium species (B. bifidum and B. infantis), with or without prebiotic compounds (arabino-galactan, short-chain fructo-oligosaccharide, iso-malto-dextrins), were orally fed to Balb/c pups (n = 192) to evaluate their potential synergistic effects on modulating the course of rhesus rotavirus (RRV) infection, as well as their ability to mediate the associated mucosal and humoral immune responses. Rotavirus-specific IgA and IgG in serum, rotavirus antigen, and specific IgA in feces were measured by ELISA. Mucosal total IgA and IgG levels were determined in Peyer's patches by flow cytometry. Significantly delayed onset (p = 0.001) and early resolution (p < 0.001) of diarrhea were observed in bifidobacteria-treated, RRV-infected mice compared with RRV-infected control mice. Supplementation with prebiotic compounds did not shorten the clinical diarrhea course more than that observed with bifidobacteria treatment alone. Rotavirus-specific IgA in feces was 16-fold elevated on d 5 postinfection in bifidobacteria-treated, RRV-infected mice compared with the RRV-infected alone group. In addition, the level of rotavirus-specific IgA in serum was four-fold higher in bifidobacteria-treated, RRV-infected litters versus mice challenged with RRV alone on 28 and 42 d postinfection. No enhancement of the immune response was found in RRV-infected mice that were treated with both bifidobacteria and prebiotic compounds over those treated with bifidobacteria only. The findings suggest that bifidobacteria may act as an adjuvant by modulating early mucosal and strong humoral rotavirus-specific immune responses, and mitigate severity of rotavirus-induced diarrhea.

Bacterial toxins and enteral feeding of premature infants at risk for necrotizing enterocolitis.

Bacterial translocation and enteral feeding are factors implicated in neonatal necrotizing enterocolitis (NEC) in the preterm infant. A cohort of 60 preterm low birth-weight (LBW) infants (600-1,600 g at birth) consecutively admitted to the neonatal intensive care unit (NICU; N = 183) were prospectively followed to evaluate the role of bacterial endotoxins (lipopolysaccharides) and enteral feeding in the development of NEC. Stage I NEC was identified in 14/60 (23%) infants. In all, 15% (9/60) of infants followed, which represented roughly 5% of higher risk, LBW infants admitted to the NICU, progressed to Stage II or III NEC disease. Infants not enterally fed (nothing by mouth [NPO]) were at greatest risk of developing NEC. No infant who was breast milk fed progressed to Stage II or III NEC. The protective effect of breast milk was most evident when compared with the combined group of NPO or formula-feeding infants per person-week at risk (RR = .15, P < .04). Toxin-producing bacteria and endotoxin levels in stool filtrates predicted early and advanced stages of NEC disease. Cytokine concentrations (interleukin-6 [IL-6]) in stool appeared of limited value in reflecting mucosally limited disease in the gastrointestinal tract. Overgrowth of toxin-producing bacteria and their toxin products may adversely affect gut barrier function; monitoring endotoxin concentrations in stool filtrates may be most clinically useful in NPO and formula-fed infants identified at risk of developing NEC. Am. J. Hum. Biol. 10:211-219, 1998. © 1998 Wiley-Liss, Inc.