Gut microbiome alteration in MORDOR I: a community-randomized trial of mass azithromycin distribution.

The MORDOR I trial1, conducted in Niger, Malawi and Tanzania, demonstrated that mass azithromycin distribution to preschool children reduced childhood mortality1. However, the large but simple trial design precluded determination of the mechanisms involved. Here we examined the gut microbiome of preschool children from 30 Nigerien communities randomized to either biannual azithromycin or placebo. Gut microbiome γ-diversity was not significantly altered (P = 0.08), but the relative abundances of two Campylobacter species, along with another 33 gut bacteria, were significantly reduced in children treated with azithromycin at the 24-month follow-up. Metagenomic analysis revealed functional differences in gut bacteria between treatment groups. Resistome analysis showed an increase in macrolide resistance gene expression in gut microbiota in communities treated with azithromycin (P = 0.004). These results suggest that prolonged mass azithromycin distribution to reduce childhood mortality reduces certain gut bacteria, including known pathogens, while selecting for antibiotic resistance.

The potential economic value of sputum culture use in patients with community-acquired pneumonia and healthcare-associated pneumonia.

OBJECTIVE: Despite numerous studies, the clinical value of sputum cultures in the management of pneumonia remains controversial; therefore, understanding the economic value of sputum cultures may help decision makers determine their appropriate use in patient management. METHODS: We developed a decision model to determine the economic and clinical value of using sputum cultures in the treatment of community-acquired pneumonia (CAP) and healthcare-associated pneumonia (HCAP) from the hospital perspective under various conditions. RESULTS: For both CAP and HCAP patients, obtaining sputum cultures resulted in similar costs compared to no culture, even if cultures cost $0. Given current clinical practices, obtaining cultures cost $539-631 more per CAP patient and $13-170 per HCAP patient compared to no culture use. However, cultures saved $8-202 per HCAP patient with a 40% probability the pathogen was the true cause (75% reduction in adverse outcomes, greater length of hospital stay (LOS) increase) to a 70% probability the pathogen was the true cause (25% reduction in outcomes and greater LOS increase and a 75% reduction in outcomes and all LOS increases). Additionally, obtaining sputum cultures had no impact on the number of adverse outcomes (i.e., adverse drug events, Clostridium difficile infection, pneumonia readmissions, additional hospitalization days). When all patients were treated with antibiotics empirically, obtaining cultures saved $4-342. CONCLUSIONS: Overall, obtaining sputum cultures does not provide significant clinical or economic benefits for CAP or HCAP patients; however, it can reduce costs and shorten overall LOS under some circumstances. Clinicians should consider their local conditions when making decisions about sputum culture use.

Multidrug and Mupirocin Resistance in Environmental Methicillin-Resistant Staphylococcus aureus (MRSA) Isolates from Homes of People Diagnosed with Community-Onset MRSA Infection.

Patients with community-onset (CO) methicillin-resistant Staphylococcus aureus (MRSA) infections contribute to MRSA contamination of the home environment and may be reexposed to MRSA strains from this reservoir. This study evaluates One Health risk factors, which focus on the relationship between humans, animals, and the environment, for the increased prevalence of multiple antimicrobial-resistant MRSA isolates in the home environment. During a trial of patients with CO-MRSA infection, MRSA was isolated from the household environment at the baseline and 3 months later, following randomization of patients and household members to mupirocin-based decolonization therapy or an education control group. Up to two environmental MRSA isolates collected at each visit were tested. MRSA isolates were identified in 68% (65/95) of homes at the baseline (n = 104 isolates) and 51% (33/65) of homes 3 months later (n = 56 isolates). The rates of multidrug resistance (MDR) were 61% among isolates collected at the baseline and 55% among isolates collected at the visit 3 months later. At the baseline, 100% (14/14) of MRSA isolates from rural homes were MDR. While antimicrobial use by humans or pets was associated with an increased risk for the isolation of MDR MRSA from the environment, clindamycin use was not associated with an increased risk for the isolation of MDR MRSA. Incident low-level mupirocin-resistant MRSA strains were isolated at 3 months from 2 (5%) of 39 homes that were randomized to mupirocin treatment but none of the control homes. Among patients recently treated for a CO-MRSA infection, MRSA and MDR MRSA were common contaminants in the home environment. This study contributes to evidence that occupant use of antimicrobial drugs, except for clindamycin, is associated with MDR MRSA in the home environmental reservoir. (This study has been registered at ClinicalTrials.gov under registration no. NCT00966446.)IMPORTANCE MRSA is a common bacterial agent implicated in skin and soft tissue infections (SSTIs) in both community and health care settings. Patients with CO-MRSA infections contribute to environmental MRSA contamination in these settings and may be reexposed to MRSA strains from these reservoirs. People interact with natural and built environments; therefore, understanding the relationships between humans and animals as well as the characteristics of environmental reservoirs is important to advance strategies to combat antimicrobial resistance. Household interactions may influence the frequency and duration of exposure, which in turn may impact the duration of MRSA colonization or the probability for recurrent colonization and infection. Therefore, MRSA contamination of the home environment may contribute to human and animal recolonization and decolonization treatment failure. The aim of this study was to evaluate One Health risk factors that may be amenable to intervention and may influence the recovery of MDR and mupirocin resistance in CO-MRSA isolates.

Factors associated with persistent colonisation with methicillin-resistant Staphylococcus aureus.

We conducted a prospective cohort study between 1 January 2010 and 31 December 2012 at five adult and paediatric academic medical centres to identify factors associated with persistent methicillin-resistant Staphylococcus aureus (MRSA) colonisation. Adults and children presenting to ambulatory settings with a MRSA skin and soft tissue infection (i.e. index cases), along with household members, performed self-sampling for MRSA colonisation every 2 weeks for 6 months. Clearance of colonisation was defined as two consecutive negative sampling periods. Subjects without clearance by the end of the study were considered persistently colonised and compared with those who cleared colonisation. Of 243 index cases, 48 (19·8%) had persistent colonisation and 110 (45·3%) cleared colonisation without recurrence. Persistent colonisation was associated with white race (odds ratio (OR), 4·90; 95% confidence interval (CI), 1·38-17·40), prior MRSA infection (OR 3·59; 95% CI 1·05-12·35), colonisation of multiple sites (OR 32·7; 95% CI 6·7-159·3). Conversely, subjects with persistent colonisation were less likely to have been treated with clindamycin (OR 0·28; 95% CI 0·08-0·99). Colonisation at multiple sites is a risk factor for persistent colonisation and may require more targeted decolonisation efforts. The specific effect of clindamycin on MRSA colonisation needs to be elucidated.

The impact of household transmission on duration of outpatient colonization with methicillin-resistant Staphylococcus aureus.

We identified eight consecutive patients who presented with a skin or soft tissue infection due to MRSA. Of seven household members of these cases, three were colonized with MRSA. The mean duration of MRSA colonization in index cases was 33 days (range 14-104), while mean duration of colonization in household cases was 54 days (range 12-95). There was a borderline significant association between having a concurrent colonized household member and a longer duration of colonization (mean 44 days vs. 26 days, P=0.08).

Patterns of Guillain-Barre syndrome in children: results from a Mexican population.

BACKGROUND: Guillain-Barré syndrome (GBS) is an acute, immune-mediated flaccid paralysis frequently associated with Campylobacter infection. Of two predominant GBS subtypes, a demyelinating subtype (acute inflammatory demyelinative polyneuropathy [AIDP]) predominates in the United States and Europe, and axonal subtype (acute motor axonal neuropathy [AMAN]) is the predominant form in China. Previous clinical studies suggested that AMAN also occurs in Mexican children. The purpose of this study was to describe the subtypes of GBS in children from Mexico City. METHODS: We prospectively studied 121 children admitted to two pediatric hospitals in Mexico City from 1996 to 2002. Clinical histories were obtained, electrophysiologic studies were performed to determine GBS subtype, and microbiologic studies were performed. RESULTS: Of the 121 children, 46 had AMAN and 32 had AIDP. The male to female ratio was 1.3 for AMAN cases (mean age = 6.3) and 3.0 for AIDP cases (mean age = 7.0). There was a strong seasonal distribution of AMAN cases in July to September. Children with AMAN, but not AIDP, had worsening of illness during hospitalization as judged by peak severity scores. Vomiting was more likely in AIDP (28.1%) vs AMAN (6.5%) (p = 0.012) and diarrhea was more common in AMAN (32.6%) than AIDP (12.5%) (p = 0.06). IgG anti-GM1 antibody titers were higher in patients with AMAN vs AIDP (p = 0.067). Anti-GD1a antibodies were equally present in both groups. Anti GQ1b titers were higher in AMAN vs AIDP (p = 0.009). Campylobacter antibody responses were positive in 44.1% of patients with AMAN and 37.0% of patients with AIDP. Twenty patients (14 = AMAN, 6 = AIDP) had positive stool cultures for C jejuni. Two serotypes, HS:19 and HS:41, accounted for 6 of 10 Campylobacter isolates available for serotyping from these cases. CONCLUSIONS: This study confirms that acute motor axonal neuropathy is an important Guillain-Barré syndrome subtype in Mexican children, is associated with diarrhea, and occurs seasonally.

Vaginal symptoms and bacterial vaginosis (BV): how useful is self-report? Development of a screening tool for predicting BV status.

Vaginal complaints compel an evaluation of bacterial vaginosis (BV), however, many cases of BV are asymptomatic. We evaluated the sensitivity and specificity of vaginal symptoms in the diagnosis of BV and examined the utility of creating a BV screening tool using clinical, behavioural and demographic characteristics. A total of 1916 pregnant women were included in this analysis. In total, 757 women screened positive for BV and over one third of BV-positive women presented without any lower genital tract symptoms (39.4%). African American race, abnormal vaginal odour, and smoking were independently related to BV positivity. A BV screening tool including these three factors was fairly predictive of BV status with the area under the ROC curve equal to 0.669. This three-item prediction rule may be useful in identifying high- risk pregnant women in need of BV screening and, given the high specificity, accurately identify the group of BV-negative pregnant women.

Recurrent catheter-related Rhodotorula rubra infection.

A 34-year-old male receiving chronic parenteral nutrition for treatment of short bowel syndrome and intermittent immunosuppressive agents for juvenile rheumatoid arthritis developed recurrent, catheter-associated Rhodotorula rubra fungemia over a one-year period. Infection with this yeast is associated with insertion of central venous catheters. Recurrence of R. rubra infection is an unusual event that presumably occurred because of chronic skin colonization by the organism.

Infected branchial cleft cyst due to Bordetella bronchiseptica in an immunocompetent patient.

A healthy 23-year-old man with fever and a tender mass in his right anterior neck was found to have a branchial cleft cyst infected with Bordetella bronchiseptica. Initial testing suggested a Brucella species, but further laboratory testing identified the organism definitively. B. bronchiseptica infection in healthy adults is an unusual event.

Absence of clonality of Campylobacter jejuni in serotypes other than HS:19 associated with Guillain-Barré syndrome and gastroenteritis.

Guillain-Barré syndrome (GBS) is recognized as a complication that occurs after Campylobacter infection. Certain Penner serotypes, such as HS:19, are linked particularly to GBS in some parts of the world, and there is good evidence for restricted genetic diversity in these isolates. However, GBS also occurs after Campylobacter infection due to other serotypes. Therefore, we asked whether Campylobacter jejuni non-HS:19 serotypes associated with GBS have a clonal structure and differ from strains isolated from patients with Campylobacter gastroenteritis. A worldwide selected population of C. jejuni non-HS:19 strains associated with GBS and gastroenteritis was analyzed by use of multilocus enzyme electrophoresis, automated ribotyping, pulsed-field gel electrophoresis, and flagellin gene typing. The results show that these isolates represent a heterogenic population and do not constitute a unique population across serotypes. No epidemiologic marker for GBS-associated strains was identified.

Molecular population genetic analysis of Campylobacter jejuni HS:19 associated with Guillain-Barré syndrome and gastroenteritis.

Infection with Campylobacter jejuni serotype HS:19 is associated with the development of Guillain-Barré syndrome (GBS). To determine whether a particular HS:19 clone is associated with GBS, multilocus enzyme electrophoresis (MLEE) was used to analyze a worldwide collection of isolates. There were 34 electropherotypes (ETs) in 3 phylogenetic clusters among 83 C. jejuni isolates. Cluster I contained all HS:19 strains, and a single ET (ET4) accounted for most HS:19 strains. HS:19 strains did not occur in any of the other clusters. ET4 contained isolates from different geographic locations, indicating global spread of this clone. Furthermore, ET4 contained isolates from patients with uncomplicated enteritis and GBS, as well as isolates from animal sources. The results of this study show that HS:19 strains comprise a clonal, although not monomorphic, population, which is distinct from non-HS:19 strains within C. jejuni. A unique clone associated with GBS was not identified by use of MLEE.

In vitro effects of photodynamic therapy on Aspergillus fumigatus.

Photodynamic therapy is a technique for killing cells with visible light after pretreatment with a photosensitizing agent. We demonstrated significant in vitro fungicidal activity against Aspergillus fumigatus of the photosensitizer Green 2W, activated with 630 nm light. This effect was both inoculum- and light dose-dependent. At a Green 2W concentration of 31.5 mg/L, there was complete killing of 2.7 x 10(1) cfu/mL with a light dose of 110 J/cm(2) and up to 2.7 x 10(6) cfu/mL with a light dose of 385 J/cm(2).

Quinolone and macrolide resistance in Campylobacter jejuni and C. coli: resistance mechanisms and trends in human isolates.

The incidence of human Campylobacter jejuni and C. coli infections has increased markedly in many parts of the world in the last decade as has the number of quinolone-resistant and, to a lesser extent, macrolide-resistant Campylobacter strains causing infections. We review macrolide and quinolone resistance in Campylobacter and track resistance trends in human clinical isolates in relation to use of these agents in food animals. Susceptibility data suggest that erythromycin and other macrolides should remain the drugs of choice in most regions, with systematic surveillance and control measures maintained, but fluoroquinolones may now be of limited use in the empiric treatment of Campylobacter infections in many regions.

Agilent 2100 bioanalyzer for restriction fragment length polymorphism analysis of the Campylobacter jejuni flagellin gene.

The Agilent 2100 bioanalyzer (Agilent Technologies, Palo Alto, Calif.) utilizes capillary electrophoresis on a microchip device (LabChip 7500; Caliper Technologies, Mountain View, Calif.) that is capable of rapidly sizing small DNA fragments. To determine whether the system could replace conventional restriction fragment length polymorphism (RFLP) typing by agarose gel electrophoresis, we compared the analyzer with conventional flagellin RFLP for typing Campylobacter jejuni. Ninety-seven isolates representing 46 Fla types were initially analyzed. Correct Fla types were detected in 59% of the isolates. The major problem with the system was in resolving samples containing multiple DNA fragments differing from 8 to 20 bp. Overall, the bioanalyzer has the potential to replace conventional RFLP analysis by gel electrophoresis, but improvements in the chip separation are needed.

Performance of two rapid, single-use immunoassays for the detection of Clostridium difficile toxin A.

Two rapid, single-use immunoassays for C. difficile toxin A, the Clearview C. DIFF A (Wampole Laboratories, Cranbury, N.J.) and the ImmunoCard Toxin A assays (Meridian Diagnostics Inc., Cincinnati, Ohio) were compared to the cytotoxin assay for their ability to detect C. difficile toxin in fecal specimens. A total of 537 specimens were tested and 47 (8.8%) were positive by the cytotoxin assay. The sensitivity, specificity, positive predictive value, and negative predictive value of the toxin A assays were as follows: 70.2% (95% CI, 57.1 to 83.3), 98.8% (95% CI, 97.8 to 99.8), 84.6% (95% CI, 73.3 to 95.9), and 97.2% (95% CI, 95.7 to 98.6) respectively for the Clearview assay; and 74.5% (95% CI, 62.0 to 86.9), 99.0% (95% CI, 98.1 to 99.9), 87.5% (95% CI, 77.3 to 97.8), and 97.6% (95% CI, 96.2 to 98.9) respectively for the ImmunoCard assay. Both toxin A assays are less sensitive than the cytotoxin assay, however, these assays offer a rapid and easy-to-perform test that may be used in conjunction with the cytotoxin assay for laboratory confirmation of C. difficile-associated disease.

Lipopolysaccharide induces expression of genes encoding pro-inflammatory cytokines and the elastin-degrading enzyme, cathepsin S, in human cervical smooth-muscle cells.

OBJECTIVE: Vaginal and amniotic infection with gram-negative bacteria is associated with preterm birth. We previously reported that human cervical smooth-muscle cells (CSMC) respond to pro-inflammatory cytokines by expressing enzymes that degrade the extracellular matrix. Our objective was to characterize the effects of lipopolysaccharide (LPS) from Escherichia coli (E coli), Bacteroides fragilis, (B frag)and Fusobacterium nucleatum (F nuc)on the expression of pro-inflammatory cytokines and the elastin-degrading enzyme, cathepsin S, in human CSMC. METHODS: Human CSMC were exposed to LPS and the expression of mRNAs encoding pro-inflammatory cytokines and cathepsin S, and selected matrix metalloproteinases (MMPs) was analyzed by Northern blotting. The effect of cytokine-neutralizing antibodies on LPS-induced cathepsin S mRNA expression also was determined. RESULTS: E coli LPS increased expression of cathepsin S 12.5-fold after 12 hours; MMP-1 and MMP-3 mRNAs also were increased 2.9- and 3.5-fold, respectively. Tumor necrosis factor (TNF)-alpha, interleukin (IL-1)alpha, and IL-1beta mRNAs were markedly up-regulated after 3 hours of LPS treatment. B frag and F nuc LPS also induced TNF-alpha and cathepsin S mRNAs. E coli LPS caused a sevenfold increase in TNF-alpha secretion after 5 to 8 hours. Antihuman TNF-alpha monoclonal antibody, but not a monoclonal antibody to the low-density lipoprotein receptor, reduced the LPS-induced increase in cathepsin S mRNA by 27%, whereas neutralizing antibodies against IL-1alpha and IL-1beta did not suppress the response. Human CSMC were shown to express the toll-like receptor (TLR-2) and TLR-4 genes, which mediate the action of LPS. TLR-2 mRNA was up-regulated by TNF-alpha. CONCLUSION: CSMC respond to LPS with increased expression of pro-inflammatory cytokines and cathepsin S. Increases in cathepsin S mRNA result only in part from the rapid induction of TNF-alpha gene expression. TNF-alpha may also augment the CSMC response to LPS by increasing expression of the LPS signaling receptor, TLR-2, which probably directly mediates LPS action. These observations provide a mechanism by which gram-negative bacteria can precipitate cervical changes associated with preterm birth.

Sequence-based identification of Mycobacterium species using the MicroSeq 500 16S rDNA bacterial identification system.

We evaluated the MicroSeq 500 16S rDNA Bacterial Sequencing Kit (PE Applied Biosystems), a 500-bp sequence-based identification system, for its ability to identify clinical Mycobacterium isolates. The organism identity was determined by comparing the 16S rDNA sequence to the MicroSeq database, which consists primarily of type strain sequences. A total of 113 isolates (18 different species), previously recovered and identified by routine methods from two clinical laboratories, were analyzed by the MicroSeq method. Isolates with discordant results were analyzed by hsp65 gene sequence analysis and in some cases repeat phenotypic identification, AccuProbe rRNA hybridization (Gen-Probe, Inc., San Diego, Calif.), or high-performance liquid chromatography of mycolic acids. For 93 (82%) isolates, the MicroSeq identity was concordant with the previously reported identity. For 18 (16%) isolates, the original identification was discordant with the MicroSeq identification. Of the 18 discrepant isolates, 7 (six unique sequences) were originally misidentified by phenotypic analysis or the AccuProbe assay but were correctly identified by the MicroSeq assay. Of the 18 discrepant isolates, 11 (seven unique sequences) were unusual species that were difficult to identify by phenotypic methods and, in all but one case, by molecular methods. The remaining two isolates (2%) failed definitive phenotypic identification, but the MicroSeq assay was able to definitively identify one of these isolates. The MicroSeq identification system is an accurate and rapid method for the identification of Mycobacterium spp.

Comparison of two selective media for the isolation of Campylobacter species from a pediatric population in Mexico.

Two selective media for the isolation of Campylobacter species, a blood containing medium (CampyBAP) and blood-free, charcoal based formulation (CCDA) were compared for the ability to isolate Campylobacter species during a 1-year period. Of the 1,132 stool samples cultured during the study, 42 Campylobacter species were recovered using both media (3.7% yield). CCDA was better than CampyBAP for isolating C. jejuni subsp jejuni (18/20 vs 8/20, P = 0.002) and for all isolates, CCDA was superior over CampyBAP (39/42 vs 13/42, P < 0.0001). Overall, CCDA is a superior medium compared with CampyBAP for isolating Campylobacter species in our study population.