Community-associated methicillin-resistant Staphylococcus aureus skin infections in a religious community.

In September 2004, an outbreak of community-associated methicillin-resistant Staphylococcus aureus (MRSA) skin and soft tissue infections (SSTI) was reported among members of a religious community. We conducted a retrospective cohort study on all 175 community members; performed a nasal carriage survey, and environmental swab testing. We identified 24 MRSA cases (attack rate 14%). In multivariate analysis, sauna use [odds ratio (OR) 19.1, 95% confidence interval (CI) 2.7-206.1] and antimicrobial use within 12 months before infection (OR 11.7, 95% CI 2.9-47.6) were risk factors for infection. MRSA nasal carriage rate was 0.6% (1/174). Nine of 10 clinical isolates and an isolate from an administrative office within the community had the pulsed-field gel electrophoresis type USA300. Targeted hygiene improvement, wound care, and environmental cleaning were implemented. We describe the first reported outbreak of MRSA SSTI in a religious community. Adherence to appropriate personal and environmental hygiene might be critical factors in controlling transmission.

The resistance and integrase genes of pACM1, a conjugative multiple-resistance plasmid, from Klebsiella oxytoca.

pACM1 is an 85-kb conjugative plasmid from a clinical isolate of Klebsiella oxytoca that encodes resistance to beta-lactams (mediated by SHV-5 extended spectrum beta-lactamase), trimethoprim, sulfonamides, tetracycline, aminoglycosides, and mercuric chloride. The expression of the aminoglycoside resistance is difficult to detect, which could have clinical implications. A region of pACM1 containing five resistance genes and two putative integrons was characterized by restriction mapping and partial DNA sequencing. One integron appears to be class I (sull type); the second lacks a recognizable 3' conserved segment. Neither integron has the BamHI site predicted for the 5' conserved segment. Plasmids encoding SHV-5 from other bacterial strains appear to be closely related to pACM1 by restriction enzyme analysis, but have resistance/ integron regions that vary in size and content from that of pACM1. Integrase-mediated recombination might be responsible for genetic divergence in a widely distributed family of pACM1-like plasmids.

Molecular epidemiology of an SHV-5 extended-spectrum beta-lactamase in enterobacteriaceae isolated from infants in a neonatal intensive care unit.

Klebsiella oxytoca that produced extended-spectrum beta-lactamase (ESBL) and were resistant to ceftazidime were isolated from infants in a neonatal intensive care unit (NICU). During a 30-week period, 3 infants developed infections and an additional 60 infants were colonized with these bacteria. The molecular typing data suggested transmission of a single strain of ceftazidime-resistant K. oxytoca among 48 of the 63 infants. The ESBL of 46 of the 48 similar isolates, 14 of the remaining 15 isolates, and 6 other Enterobacteriaceae appeared to be associated with a conjugative plasmid of approximately 85 kb. The ESBL gene was cloned, and DNA sequencing confirmed that the ESBL was an SHV-5. Hybridization data suggested that the SHV-5 gene was transmitted to other Enterobacteriaceae in vivo. The spread of the ESBL was reduced through adherence to infection control practices.

Cat scratch disease in two children presenting with fever of unknown origin: imaging features and association with a new causative agent, Rochalimaea henselae.

OBJECTIVE: To report the clinical course, imaging findings, and method of diagnosis of two patients with systemic manifestations of cat scratch disease, presenting with fever of unknown origin. DESIGN: Case study. PATIENTS: Two children with fever of unknown origin who had multiple lesions in the liver and spleen, shown on ultrasound, computed tomography, and magnetic resonance imaging. Initial diagnoses were Kawasaki disease (case 1) and metastatic neuroblastoma (case 2). RESULTS: Biopsy material showed granulomatous hepatitis in both patients. The diagnoses were confirmed by positive assays for Rochalimaea henselae, currently thought to be the causative agent of cat scratch disease. CONCLUSION: Cat scratch disease presenting as fever of unknown origin is now well described and can be more readily diagnosed because of the availability of new serologic assays, as well as polymerase chain reaction assays for R henselae DNA in tissue specimens.

Measles antibodies in women and infants in the vaccine era.

The present investigation was done to determine whether measles enzyme immune assay (EIA) absorbency values were lower in women born in the vaccine era after 1963 and their infants in an upstate New York metropolitan area, an area of low measles incidence during the past 10 years compared with women born before the measles vaccine era who had natural measles. Aliquots of 202 sera from mother-infant pairs collected for other purposes from November 1990 to June 1991 at Albany Medical Center Hospital were tested by EIA. The demographic data available for analysis were maternal age and infant gestational age. Measles mean absorbency values were analyzed according to maternal age. Of 202 mother-infant pairs, 30% of mothers and 17% of their infants were seronegative (EIA < 0.16). Mothers born before 1963 and their infants had significantly higher mean EIA absorbency values than mothers born after 1963 and their infants (P < 0.002). The percent seropositive for measles antibodies by EIA for mothers born before 1963 and their infants, 87% and 94%, respectively, was significantly higher than the percent seropositive for mothers born after 1963 and their infants, 61% and 69%, respectively (P = 0.0001). Since the mean measles antibodies as measured by EIA absorbency were significantly lower in the mothers born after 1963 and their infants compared with women born before the vaccine era, the strategy for measles control in the future may have to include lowering the age of infant immunization.

Relatedness of coagulase-negative staphylococci causing bacteremia in low-birthweight infants.

OBJECTIVE: To investigate coagulase-negative staphylococcus (CONS) causing bacteremia in a neonatal intensive care unit (NICU). DESIGN: A 14-month retrospective review of 47 infants in the NICU with CONS bacteremia was undertaken to determine CONS glycocalyx production, plasmid pattern, total DNA restriction fragment polymorphism, and clinical risk factors. RESULTS: The isolates included 32 Staphylococcus epidermidis, six Staphylococcus haemolyticus, four Staphylococcus warneri, four Staphylococcus saprophyticus, and one Staphylococcus hominis. Sixty-five percent of S epidermidis produced glycocalyx; other species did not. Oxacillin resistance (52%) and the antibiograms of the CONS were consistent with other units in the hospital. Five similar CONS plasmid patterns were found among 16 isolates; 31 isolates had unique patterns. Extractions of total DNA from these isolates were digested using HindIII, HaeIII, and BstEII. Those with similar restriction fragment length patterns could not linked as nosocomially transmitted among infants with bacteremia. CONCLUSION: Our observations suggest that multiple strains of CONS infect infants in the NICU who have similar risk factors. Although current infection control practices limit transmission of a pathogen, they do not prevent CONS bacteremias.

Prevention of gram-positive sepsis in neonates weighing less than 1500 grams.

A prospective, randomized study to evaluate the effectiveness of a continuous low-dose vancomycin infusion to prevent nosocomial gram-positive bacteremia was initiated within the first 2 weeks of life in neonates weighing < 1500 gm. Seventy-one infants received constant infusion of vancomycin (25 micrograms/ml) mixed with their total parenteral nutrition solution; 70 infants served as control subjects. The groups were clinically similar in birth weight, estimated gestational age, and severity of illness. Administration of vancomycin was begun at a mean age of 5.4 +/- 2.9 days. Infants had mean serum vancomycin concentrations of 2.4 micrograms/ml, and received vancomycin for a mean of 11 +/- 7 days. No vancomycin-resistant organisms were detected in surveillance cultures during the 2-year study period. Twenty-four of seventy control infants, in comparison with 1 of 71 infants receiving vancomycin, had gram-positive bacteremia (p < 0.001). The addition of a low dose of vancomycin to alimentation fluids virtually eliminated the incidence of gram-positive bacteremia in an at-risk population of very low birth weight infants. However, the widespread use of vancomycin in total parenteral nutrition solution is not recommended until better data on the emergence of vancomycin-resistant organisms are available.

Open reading frames UL44, IRS1/TRS1, and UL36-38 are required for transient complementation of human cytomegalovirus oriLyt-dependent DNA synthesis.

Previous results showed that plasmids containing human cytomegalovirus (HCMV) oriLyt are replicated after transfection into permissive cells if essential trans-acting factors are supplied by HCMV infection (D. G. Anders, M. A. Kacica, G. S. Pari, and S. M. Punturieri, J. Virol. 66:3373-3384, 1992). We have now used oriLyt as a reporter of HCMV DNA replication in a transient complementation assay in which cotransfected cosmid clones, instead of HCMV infection, provided essential trans-acting factors. Complemented replication was oriLyt dependent and phosphonoformic acid sensitive and produced tandem arrays typical of HCMV lytic-phase DNA synthesis. Thus, this assay provides a valid genetic test to find previously unidentified genes that are essential for DNA synthesis and to corroborate functional predictions made by nucleotide sequence comparisons and biochemical analyses. Five cosmids were necessary and sufficient to produce origin-dependent DNA synthesis; all but one of these required cosmids contain at least one candidate homolog of herpes simplex virus type 1 replication genes. We further used the assay to define essential regions in two of the required cosmids, pCM1017 and pCM1052. Results presented show that UL44, proposed on the basis of biochemical evidence to be the HCMV DNA polymerase accessory protein, was required for complementation. In addition, three genomic regions encoding regulatory proteins also were needed to produce origin-dependent DNA synthesis in this assay: (i) IRS1/TRS1, which cooperates with the major immediate-early proteins to activate UL44 expression; (ii) UL36-38; and (iii) the major immediate-early region comprising IE1 and IE2. Combined, these results unequivocally establish the utility of this approach for mapping HCMV replication genes. Thus, it will now be possible to define the set of HCMV genes necessary and sufficient for initiating and performing lytic-phase DNA synthesis as well as to identify those virus genes needed for their expression in human fibroblasts.

Boundaries and structure of human cytomegalovirus oriLyt, a complex origin for lytic-phase DNA replication.

We have localized a cis-acting sequence that promotes initiation of lytic-phase DNA replication (oriLyt) within the HindIII D fragment of the human cytomegalovirus (HCMV) AD169 genome and investigated its sequence requirements by testing the ability of plasmid constructs to mediate DNA replication in a transient transfection-plus-infection assay. Replication of plasmids containing HCMV oriLyt required at least the virus-specified DNA polymerase activity supplied by HCMV infection of transfected cells and was autonomous in that it did not result from recombination with the virus genome. Progeny molecules in the transient assay were high-molecular-weight tandem oligomers, which is consistent with predictions of a rolling-circle model. Experiments testing subclones of HindIII-D defined a core 2.4-kbp region containing elements required for oriLyt function that extended rightward from around 1.0 kbp upstream of UL57 near the middle of the long unique component of the virus genome. Sequences flanking this core also were needed for full activity. The defined region contains at least four clustered sets of repeated sequence elements identical to or candidate counterparts of elements present in the corresponding cytomegalovirus Colburn lytic-phase replication origin. These elements are novel in that they apparently do not correspond to previously characterized motifs. Also present are multiple copies of elements similar to known binding sites for the transcription factors ATF/CREB, MLTF/USF, and Sp1. Preliminary deletion analysis suggests that multiple components within the boundaries of oriLyt cooperate to enable initiation of HCMV lytic-phase DNA synthesis.

Immune response to guinea pig cytomegalovirus polypeptides and cross reactivity with human cytomegalovirus.

The immune response to guinea pig cytomegalovirus (gpCMV) was evaluated by immunoblotting. Preinoculation guinea pig plasma did not react with gpCMV antigen, whereas convalescent plasma reacted to at least 18 gpCMV-specific polypeptides. The initial immune response was primarily directed at polypeptides with MWs of 100, 75, and 56 kDa. Over 80% of plasma collected more than 29 days after viral inoculation reacted to these polypeptides and also to those with MW of 54, 52, and 38 kDa. In this report, we also demonstrate cross reactivity between gpCMV and human CMV (HCMV). Human immunoglobulin (IVIG) reacted to at least 20 HCMV polypeptides and cross reacted with six gpCMV polypeptides. GpCMV convalescent plasma also reacted with HCMV polypeptides.

Local and systemic antibody response to rotavirus WC3 vaccine in adult volunteers.

An evaluation of the safety and immunogenicity of WC3 rotavirus vaccine was evaluated in adult volunteers. Pre- and post-vaccination titers of neutralizing antibody to WC3 and to the four human rotavirus serotypes as well as serum and stool rotavirus IgA levels were measured. Vaccination was safe and did not induce elevation of liver enzymes. None of the 12 volunteers receiving WC3 vaccine shed detectable amounts of virus although antibody rises were detected in 11 of 12 vaccines. Nine developed and increase in WC3 neutralizing antibody, one additional subject had a rise in Wa (human serotype 1) neutralizing antibody while another subject only developed a rise in stool rotavirus IgA. All of the vaccine recipients with a rise in WC3 neutralizing antibody also developed a rise in neutralizing antibody against at least one of the four most common human rotavirus serotypes. A stool IgA rotavirus antibody response was detected in 6 of 9 WC3 recipients with measurable stool antibody. None of the control subjects developed significant rises in any of the antibody titers measured. WC3 rotavirus vaccine appears to be safe and induces systemic and local immune responses in adults suggesting that further evaluation of WC3 should be considered in infants.