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Resistance patterns among nosocomial pathogens: trends over the past few years.

Multiple surveillance studies have demonstrated that resistance among prevalent pathogens is increasing at an alarming rate, leading to greater patient morbidity and mortality from nosocomial infections. Among Gram-positive organisms, the most important resistant pathogens are methicillin- (oxacillin-)resistant Staphylococcus aureus, beta-lactam-resistant and multidrug-resistant pneumococci, and vancomycin-resistant enterococci. Important causes of Gram-negative resistance include extended-spectrum beta-lactamases (ESBLs) in Klebsiella pneumoniae, Escherichia coli, and Proteus mirabilis, high-level third-generation cephalosporin (Amp C) beta-lactamase resistance among Enterobacter species and Citrobacter freundii, and multidrug-resistance genes observed in Pseudomonas aeruginosa, Acinetobacter, and Stenotrophomonas maltophilia. In selecting an empiric treatment for a nosocomial infection, one should consider the prevalent resistance patterns. Antimicrobials used for the treatment of nosocomial infections should be effective against any likely resistant pathogens and should not further promote the development of resistance. Recent data suggest that because of ESBLs and high-level amp C beta-lactamase resistances, use of third-generation cephalosporins may be ineffective in many patients with nosocomial infections. In addition, use of these agents may allow overgrowth of inherently resistant enterococci. The role of fluoroquinolones in the empiric treatment of nosocomial infections is also being limited by new resistance patterns and increasing resistance levels. Available antimicrobials with good activity against many resistant pathogens include the carbapenems, piperacillin/tazobactam, and cefepime. In addition, several new agents with good activity against Gram-positive organisms are in development or have been recently released. Appropriate antimicrobial selection, surveillance systems, and effective infection-control procedures are key partners in limiting antimicrobial-resistant pathogen occurrence and spread.

Anti-Bacterial Agents↗

Management of hemodialysis catheter-related bacteremia with an adjunctive antibiotic lock solution.

BACKGROUND: Tunneled dialysis catheters are complicated by frequent systemic infections. Standard therapy of catheter-associated bacteremia involves both systemic antibiotics and catheter replacement. Recent data suggest that biofilms in the catheter lumen are responsible for the bacteremia, and that instillation of an antibiotic lock (highly concentrated antibiotic solution) into the catheter lumen after dialysis sessions can eradicate the biofilm. METHODS: We analyzed prospectively the efficacy of an antibiotic lock protocol, in conjunction with systemic antibiotics, for treatment of patients with dialysis catheter-associated bacteremia without catheter removal. Protocol success was defined as resolution of fever and negative surveillance cultures one week following completion of the protocol. Protocol failure was defined as persistence of fever or surveillance cultures positive for any pathogen. In addition, infection-free catheter survival was compared to that observed in institutional historical control patients treated with catheter replacement. RESULTS: Blood cultures were positive in 98 of 129 of episodes (76%) in which patients dialyzing with a catheter had fever or chills. Protocol success occurred in 40 of 79 infected patients (51%) treated with the antibiotic lock. Protocol failure occurred in 39 cases (49%): 7 had persistent fever, 15 had positive surveillance cultures (9 for Candida and 6 for bacteria), and 17 required catheter removal due to malfunction. Each of the pathogens in the surveillance cultures was different from the original pathogen in that patient. Eight of the 9 secondary Candida infections and all 6 secondary bacterial infections resolved after catheter exchange and specific antimicrobial treatment. Overall catheter survival with the antibiotic lock protocol was similar to that observed among patients managed with catheter replacement (median survival, 64 vs. 54 days, P = 0.24). CONCLUSIONS: Use of an antibiotic lock, in conjunction with systemic antibiotic therapy, can eradicate catheter-associated bacteremia while salvaging the catheter in about one half of cases. Moreover, this management approach offers clinical advantages over routine catheter exchange.

Aged↗

Antivirals other than for HIV therapy.

This review concentrates on drugs directed at viruses other than HIV and does not include anti-HIV drugs. Many antivirals are nucleoside analogues, although new classes of enzyme inhibitors are being developed for treatment of HIV (proteases) and enteroviruses. Antisense drugs and receptor blockers have recently been approved. Regardless of mechanism, antivirals are predominantly virustatic, not virucidal, and usually require help from the host immune system to either completely eliminate pathogens (e.g., influenza) or to provide sufficient immune surveillance to prevent a latent pathogen from reactivating (e.g., the herpesviruses). Viruses by nature are intracellular pathogens, using the host cell to produce progeny. Often the viral pathogen uses the host cell machinery or enzyme system to facilitate replication. At times the virus usurps nearly the entire intracellular system for replication and may shut down all functional host cell output for host-determined products. Because of the intracellular nature of viruses and because viruses use many "normal" host cell factors, functions, and systems for replication, antivirals can have notable toxicities to host cells. As antivirals inhibit viral activity in the viral-infected host cells (these encompass a minority of the total host cell numbers), they may also negatively affect functions in the virus-uninfected host cells. These alterations may be biochemical, detected only if sought specifically, or clinically obvious toxicities. Either may limit the use of some antivirals to severe or life-threatening situations.

Antiviral Agents↗

Assessment of pathogen frequency and resistance patterns among pediatric patient isolates: report from the 2004 SENTRY Antimicrobial Surveillance Program on 3 continents.

Selecting empiric or directed therapy for pathogens isolated from pediatric patients can be problematic. Many antimicrobial agents are not indicated for use in pediatric patients, and regional variations of resistance mechanisms have been reported. The purpose of this study was to analyze antimicrobial resistance patterns and pathogen occurrence rates in pediatric-aged patient infections on 3 continents using data from the SENTRY Antimicrobial Surveillance Program. A total of 3537 clinical isolates were collected from 47 medical centers in 2004. With a protocol that dictated a sampling of 80 consecutive isolates from children (< or =18 years of age), all samples were forwarded to a central laboratory for reference susceptibility testing. Broth microdilution methods and current Clinical and Laboratory Standards Institute breakpoint criteria were used. The 15 most frequently observed pathogens accounted for 93.6% of all isolates. Staphylococcus aureus was the most common pathogen isolated in North America (27.4%) and Europe (19.0%), but Escherichia coli was most common in Latin America (19.3%). All Streptococcus pneumoniae strains from North America and Latin America were susceptible to the newer fluoroquinolones, gatifloxacin and levofloxacin. However, 2 S. pneumoniae strains from Italy were resistant to gatifloxacin, levofloxacin, and ciprofloxacin (> or =4 microg/mL). Ribotype and pulsed-field gel electrophoresis patterns found that these resistant pneumococci were clonal. Numerous strains of Klebsiella spp. (22.5%), E. coli (4.5%), and Proteus mirabilis (4.9%) exhibited phenotypic extended-spectrum beta-lactamase resistance patterns. Four Pseudomonas aeruginosa strains (3 from Latin America and 1 from Europe) were multidrug resistant, 2 P. aeruginosa isolates from Turkey were resistant to polymyxin B (> or =4 microg/mL), and 8.7% of Stenotrophomonas maltophilia isolates from Latin America were resistant to the "drug of choice", trimethoprim/sulfamethoxazole. Physicians should be aware of pathogen occurrences that vary by children's age, geographic location, and prior antimicrobial exposure. Therefore, continued surveillance will be necessary to monitor emerging antimicrobial resistance in the pediatric patient population, especially because new agents such as the fluoroquinolones are used to a greater extent in this age group.

Adolescent↗

Epidemiology of cutaneous leishmaniasis in Colombia: environmental and behavioral risk factors for infection, clinical manifestations, and pathogenicity.

Through a longitudinal, active surveillance for Leishmania (Viannia) braziliensis and Leishmania (Viannia) panamensis infection and lesions on the Pacific Coast of Colombia, risk factors for infection (leishmanin skin test conversion), leishmanial lesions, and pathogenicity were examined. Risk factor information was obtained prior to and independently of case ascertainment. Similar factors were associated with acquisition of infection and of leishmaniasis, including male sex, age > 10 years, and farming occupation. The behaviors of entering the forest after sunset, hunting, and lumbering were most strongly associated with Leishmania infection independently of age, sex, and farming occupation. Environmental conditions associated with infection, including tall trees near the home, home located > 15 m from the nearest neighbor, and floor and roof made of open material, were less strong predictors of risk. Pathogenicity, the risk of lesion given a new infection, was reduced in those > 30 years of age and those entering the forest frequently.

Adolescent↗

Antimicrobial susceptibility of community-acquired respiratory tract pathogens in North America in 1999-2000: findings of the PROTEKT surveillance study.

The PROTEKT surveillance study commenced in 1999 to examine the antimicrobial susceptibility of community-acquired respiratory pathogens. We report here the results from 2371 isolates collected during 2000 by North American centers (Canada, n = 7; USA, n = 8). Overall, 21.3% of pneumococci (n = 687) were penicillin G-resistant (Canada, 10.3%; USA, 32.6%). Corresponding rates of erythromycin resistance were 16.3% and 31.5%. Telithromycin inhibited all penicillin- and erythromycin-resistant isolates at < or =1 microg/ml. Among 612 Hemophilus influenzae isolates, 22.4% were beta-lactamase-positive. Antimicrobial susceptibility of H. influenzae varied between 82.4% (clarithromycin) and 100% (cefpodoxime, levofloxacin). Importantly, one isolate was found to be resistant to both moxifloxacin and ciprofloxacin. Most Moraxella catarrhalis isolates were highly susceptible to the antimicrobials tested, except ampicillin. All Streptococcus pyogenes isolates (n = 382) were penicillin-susceptible and 5.2% were non-susceptible to erythromycin. S. pyogenes showed cross-resistance to other macrolides yet remained inhibited by telithromycin at < or =0.5 microg/ml. Methicillin resistance among Staphylococcus aureus was common (19.9%), particularly in the USA. The PROTEKT study confirms the widespread prevalence of antimicrobial resistance among common respiratory pathogens in North America, and hence the need for continued surveillance to guide optimal empiric therapy for community-acquired respiratory tract infections.

Anti-Bacterial Agents↗

Role of surveillance cultures in prevention and treatment of fungal infections.

Fungal surveillance cultures have been studied as potential predictors of invasive or disseminated mycoses. Several studies have demonstrated that the presence of Candida tropicalis in mucosal surveillance cultures has a high predictive value for invasive fungal infection due to this pathogen in granulocytopenic patients. By comparison, surveillance cultures for Candida albicans have a poor positive predictive value for invasive fungal infection. The value of routine surveillance cultures of the nares for Aspergillus spp. has not been consistently confirmed. The use of surveillance cultures for less common fungal pathogens, such as Trichosporon beigelii, also remains unclear. Fungal surveillance cultures of the inanimate hospital environment have proven useful in identifying the source of conidia in well-defined clusters or outbreaks of nosocomial aspergillosis and other mycoses. As investigational tools, fungal surveillance cultures also may be useful for studying the effects of new antifungal agents on mucosal flora. Fungal surveillance cultures, especially for C. tropicalis and possibly Aspergillus spp. in high-risk populations, may be useful when a pathogen-directed approach to antifungal therapy is used. However, the time required, diagnostic limitations, and expense of routine mucosal fungal surveillance cultures must be balanced against the effect of this information on therapeutic decisions. Empirical antifungal therapy and early diagnostic approaches for high-risk patients may obviate the need for routine fungal surveillance cultures while decreasing the frequency of invasive mycoses.

Amphotericin B↗

Predominant pathogens in hospital infections.

To determine the distribution of pathogens causing nosocomial infections in United States hospitals, we analysed data from the National Nosocomial Infections Surveillance (NNIS) System. From October 1986 to December 1990, amongst hospitals conducting hospital-wide surveillance, the five most commonly reported pathogens were Escherichia coli (13.7%), Staphylococcus aureus (11.2%), enterococci (10.7%), Pseudomonas aeruginosa (10.1%), and coagulase-negative staphylococci (9.7%). The commonest pathogens reported by site included, bloodstream: coagulase-negative staphylococci, S. aureus, enterococci, E. coli, and Candida spp.; lower respiratory tract infection: S. aureus, P. aeruginosa and Enterobacter spp.; surgical wound infection: S. aureus, enterococci and coagulase-negative staphylococci; and urinary tract infection: E. coli, enterococci, and P. aeruginosa. Among hospitals conducting intensive care unit (ICU) surveillance, the commonest pathogens were P. aeruginosa (12.4%), S. aureus (12.3%), coagulase-negative staphylococci (10.2%), Candida spp. (10.1%), Enterobacter spp. and enterococci (8.6% each). In the ICUs, the commonest pathogens found in the bloodstream were coagulase-negative staphylococci, S. aureus, and enterococci; in lower respiratory tract infections P. aeruginosa, S. aureus, and enterococci; in surgical wound infections enterococci, coagulase-negative staphylococci, and Enterobacter spp. and in urinary tract infections Candida spp., E. coli, enterococci, P. aeruginosa, and Enterobacter spp. These data show that S. aureus, E. coli and P. aeruginosa remain important nosocomial pathogens, that coagulase-negative staphylococci, enterococci and C. albicans are pathogens of increasing importance, and that the distribution of pathogens differs by site and hospital location.

Adult↗

Nosocomial bloodstream infections in pediatric patients in United States hospitals: epidemiology, clinical features and susceptibilities.

BACKGROUND: We identified the predominant pathogens and antimicrobial susceptibilities of nosocomial bloodstream isolates in pediatric patients in the US Prospective surveillance for nosocomial bloodstream infections at 49 hospitals during a 6-year period [Surveillance and Control of Pathogens of Epidemiologic Importance (SCOPE)] detected 22 609 bloodstream infections, of which 3432 occurred in patients < or =16 years of age. RESULTS: Gram-positive organisms accounted for 65% of cases, Gram-negative organisms accounted for 24% of cases and 11% were caused by fungi. The overall crude mortality was 14% (475 of 3432) but notably higher for infections caused by Candida spp. and Pseudomonas aeruginosa, 20 and 29%, respectively. The most common organisms were coagulase-negative staphylococci (43%), enterococci, Staphylococcus aureus and Candida spp. (each, 9%). The mean interval between admission and infection averaged 21 days for coagulase-negative staphylococci, 25 days for S. aureus and Candida spp., 32 days for Klebsiella spp. and 34 days for Enterococcus spp. The proportion of methicillin-resistant S. aureus increased from 10% in 1995 to 29% in 2001. Vancomycin-resistance was seen in 1% of Enterococcus faecalis and in 11% of Enterococcus faecium isolates. CONCLUSION: Nosocomial BSI occurred predominantly in very young and/or critically ill children. Gram-positive pathogens predominated across all ages, and increasing antimicrobial resistance was observed in pediatric patients.

Age Distribution↗

Genomic and bioinformatics analysis of HAdV-7, a human adenovirus of species B1 that causes acute respiratory disease: implications for vector development in human gene therapy.

Human adenovirus serotype 7 (HAdV-7) is a reemerging pathogen identified in acute respiratory disease (ARD), particularly in epidemics affecting basic military trainee populations of otherwise healthy young adults. The genome has been sequenced and annotated (GenBank accession no. ). Comparative genomics and bioinformatics analyses of the HAdV-7 genome sequence provide insight into its natural history and phylogenetic relationships. A putative origin of HAdV-7 from a chimpanzee host is observed. This has implications within the current biotechnological interest of using chimpanzee adenoviruses as vectors for human gene therapy and DNA vaccine delivery. Rapid genome sequencing and analyses of this species B1 member provide an example of exploiting accurate low-pass DNA sequencing technology in pathogen characterization and epidemic outbreak surveillance through the identification, validation, and application of unique pathogen genome signatures.

Adenovirus Infections, Human↗

Bacterial pathogens isolated from patients with bloodstream infection: frequencies of occurrence and antimicrobial susceptibility patterns from the SENTRY antimicrobial surveillance program (United States and Canada, 1997).

The SENTRY Program was established in January 1997 to measure the predominant pathogens and antimicrobial resistance patterns of nosocomial and community-acquired infections over a broad network of sentinel hospitals in the United States (30 sites), Canada (8 sites), South America (10 sites), and Europe (24 sites). During the first 6-month study period (January to June 1997), a total of 5,058 bloodstream infections (BSI) were reported by North American SENTRY participants (4,119 from the United States and 939 from Canada). In both the United States and Canada, Staphylococcus aureus and Escherichia coli were the most common BSI isolates, followed by coagulase-negative staphylococci and enterococci. Klebsiella spp., Enterobacter spp., Pseudomonas aeruginosa, Streptococcus pneumoniae, and beta-hemolytic streptococci were also among the 10 most frequently reported species in both the United States and Canada. Although the rank orders of pathogens in the United States and Canada were similar, distinct differences were noted in the antimicrobial susceptibilities of several pathogens. Overall, U.S. isolates were considerably more resistant than those from Canada. The differences in the proportions of oxacillin-resistant S. aureus isolates (26.2 versus 2.7% for U.S. and Canadian isolates, respectively), vancomycin-resistant enterococcal isolates (17.7 versus 0% for U.S. and Canadian isolates, respectively), and ceftazidime-resistant Enterobacter sp. isolates (30.6 versus 6.2% for U.S. and Canadian isolates, respectively) dramatically emphasize the relative lack of specific antimicrobial resistance genes (mecA, vanA, and vanB) in the Canadian microbial population. Among U.S. isolates, resistance to oxacillin among staphylococci, to vancomycin among enterococci, to penicillin among pneumococci, and to ceftazidime among Enterobacter spp. was observed in both nosocomial and community-acquired pathogens, although in almost every instance the proportion of resistant strains was higher among nosocomial isolates. Antimicrobial resistance continues to increase, and ongoing surveillance of microbial pathogens and resistance profiles is essential on national and international scales.

Anti-Bacterial Agents↗

Healthcare-facility-based SARS-CoV-2 genomic surveillance in Brazil: experience from the global action in healthcare network.

UNLABELLED: Genomic sequencing is essential to effectively monitor the SARS-CoV-2 evolution and spread of its lineages. Healthcare-facility-based SARS-CoV-2 genomic surveillance has been proposed as a valuable strategy, considering the characteristics of its target population. As part of the Centers for Disease Control and Prevention's Global Action in Healthcare Network program, this study aimed to describe the distribution and frequency of SARS-CoV-2 lineages in two tertiary-care hospitals in Brazil, where the genomic sequencing capacity is limited. Whole-genome sequencing of SARS-CoV-2 samples obtained from 993 healthcare workers (75.4%) and inpatients (24.6%) was analyzed between February 2023 and August 2024. In total, 113 distinct lineages were identified. Notably, we observed a temporal replacement of predominant lineages corresponding to three distinct epidemic waves: the first wave dominated by XBB.1.5 and XBB.2.3 (February 2023 to June 2023), the second by GK.1.1 and JD.1.1 (September 2023 to December 2023), and the third by JN.1 and JN.1.9 (January 2024 to April 2024). JN.1.9 was the only lineage with a significantly higher prevalence among healthcare workers compared to inpatients. Additionally, we identified cases of co-infection with genetically distinct variants, underscoring the potential for healthcare-based monitoring to capture events relevant to viral evolution. Overall, our findings were consistent with those observed across Brazil, suggesting that this strategy may be valuable for SARS-CoV-2 genomic surveillance. They also indicate a clear temporal pattern of lineage replacement, reflecting successive waves driven by emerging variants and rapid global dissemination. IMPORTANCE: Genomic surveillance of SARS-CoV-2 remains essential for identifying emerging variants with increased transmissibility, immune escape, or pathogenicity. While most genomic surveillance efforts focus on community-based sampling, a healthcare-facility-based strategy may offer a complementary approach. In this study, we describe SARS-CoV-2 lineage dynamics over an 18-month period among healthcare workers and hospitalized patients in southern Brazil. Our findings align closely with regional and national trends, supporting the value of healthcare-facility-based SARS-CoV-2 genomic surveillance for documenting the local genomic landscape and demonstrating the feasibility and value of this approach in settings with limited genome sequencing capacity. Additionally, this approach may be applicable to other respiratory viruses in healthcare settings; however, further studies would be needed to confirm this.

Humans↗

Innate recognition of bacteria by a macrophage cytosolic surveillance pathway.

Host recognition of bacterial pathogens is a critical component of the immune response. Intracellular bacterial pathogens are able to evade the humoral immune system by residing within the host cell. Here we show the existence of an innate host surveillance mechanism in macrophages that specifically distinguishes bacteria in the cytosol from bacteria in the vacuole. Recognition of Gram-positive and Gram-negative bacterial products by this surveillance system results in transcription of the ifnb gene. The activation of cytosol-specific signaling is associated with translocation of NF-kappaB into the nucleus and phosphorylation of the p38 mitogen-activated protein (MAP) kinase. Activation of the p38 kinase is required for the induction of gene expression by the cytosolic surveillance pathway. Our studies suggest that infection by intracellular bacterial pathogens results in an immune response distinct from that of infection by extracellular bacterial pathogens.

Animals↗

Multi-locus sequence typing: a tool for global epidemiology.

The characterization of pathogenic isolates plays a pivotal role in the epidemiology of infectious diseases, generating the information necessary for identifying, tracking, and intervening against disease outbreaks. In 1998 multi-locus sequence typing (MLST) was proposed as a nucleotide sequence-based approach that could be applied to many bacterial pathogens. It combined developments in high-throughput sequencing and bioinformatics with established population genetics techniques to provide a portable, reproducible, and scalable typing system that reflected the population and evolutionary biology of bacterial pathogens. MLST schemes have been developed for a variety of procaryotic and eucaryotic pathogens and the data generated have contributed to both epidemiological surveillance and fundamental studies of pathogen biology.

Bacteria↗

Increased antibiotic resistance in respiratory tract pathogens: PROTEKT US--an update.

Three major North American surveillance programs have tracked antimicrobial resistance patterns among isolates of Streptococcus pneumoniae and other common respiratory tract pathogens. The Canadian Bacterial Surveillance Network shows the progressive increase in resistance among pneumococcal S. pneumoniae to penicillin, trimethoprim-sulfamethoxazole, macrolides, and fluoroquinolones. The data from the Tracking Resistance in the United States Today study also show a steady rise in pneumococcal resistance among common antibiotics as well as an increase in multidrug-resistant S. pneumoniae. The US component of the Prospective Resistant Organism Tracking and Epidemiology for the Ketolide Telithromycin study has detected increasing resistance to many antimicrobial agents among common respiratory isolates, with marked geographic variations in resistance patterns. The patterns of resistance detected by these major surveillance programs are a warning signal regarding the continued emergence of resistance among community-acquired respiratory tract pathogens.

Canada↗

Bacteriology of surgical wound infections in a tertiary care hospital in Turkey.

OBJECTIVE: To determine the spectrum of the pathogens cultured from surgical wound infections and assess their antimicrobial drug resistances. DESIGN: Laboratory-based retrospective study for the five year period. SETTING: A four hundred bed, tertiary-care university hospital in Turkey. RESULTS: Overall 621 pathogens were identified from January 1999 to January 2004. Of these isolates, 431 (69%) were gram-positive, 178 (29%) were gram-negative bacteria and also 12 (2%) were identified as Candida albicans. The most common organism was Staphylococcus aureus (50%), followed by Escherichia coli (8%), Streptococcus pyogenes (7%), Pseudomonas aeruginosa (7%), coagulase-negative staphylococci (6%), Enterococcus faecalis (4%), Enterobacter spp. (4%), Klebsiella pneumoniae (3%), Acinetobacter spp. (3%), Proteus spp. (3%), group B. B-haemolytic streptococci (2%), Candida albicans (2%), and Citrobacter spp. (1%). The rate of resistance to methicillin in staphylococci and multidrug resistance in S. aureus were 31% and 12%, respectively. There was no increase in resistance to methicillin by years. Piperacillin/tazobactam, sefoperazone/sulbactam, carbapenems, ofloxacin and amikacin were the most active agents against gram-negative isolates. The rates of extended spectrum beta-lactamase production in K. pneumoniae and E. coli strains were determined as 14%, and 6%, respectively. CONCLUSION: Methicillin resistant Staphylococcus aureus (MRSA) is emerging as a major pathogen in surgical wound infections. We concluded that antimicrobial treatment of surgical wound infections should include empiric coverage for MRSA. The surveillance of resistance in pathogens causing surgical wound infections is necessary to promote the appropriate therapeutic choices for these infections.

Drug Resistance, Bacterial↗

Antibacterial resistance of community-acquired respiratory tract pathogens recovered from patients in Germany and activity of the Ketolide Telithromycin: results from the PROTEKT surveillance study (1999-2000).

BACKGROUND: The Prospective Resistant Organism Tracking and Epidemiology for the Ketolide Telithromycin (PROTEKT) longitudinal global surveillance study examines the antibacterial susceptibility of community-acquired respiratory pathogens. METHODS AND RESULTS: Data from isolates collected in Germany in 1999-2000 in the PROTEKT study show that 8.3% of pneumococcal isolates (n = 325) had reduced susceptibility to penicillin and 2.2% were fully resistant. Erythromycin resistance was 15.7% overall and particularly high in Leipzig (31.6%). All penicillin- and erythromycin-resistant strains were inhibited by telithromycin (MIC < or =0.5 mg/l) and linezolid (MIC < or =2 mg/l). Beta-lactamase was produced by 3.2% of Haemophilus influenzae (9/284) and 89.5% of Moraxella catarrhalis strains (111/124). All Streptococcus pyogenes isolates (n = 87) were susceptible to penicillin, although 9.2% were resistant to macrolides. CONCLUSIONS: Penicillin resistance in Germany remains low; however, the prevalence of antimicrobial resistance among common respiratory pathogens is rising, particularly against macrolides. Continued surveillance is necessary to guide optimal empirical therapy, and new antimicrobials, like telithromycin, need to be developed with improved potency against target pathogens and low propensity for the development of resistance.

Anti-Bacterial Agents↗

A fatal attraction: Mycobacterium tuberculosis and HIV-1 target DC-SIGN to escape immune surveillance.

Dendritic cells (DCs) are vital in the defense against pathogens. However, it is becoming increasingly clear that some pathogens subvert DC functions to escape immune surveillance. For example, HIV-1 targets the DC-specific C-type lectin DC-SIGN (DC-specific intercellular-adhesion-molecule-3-grabbing nonintegrin) to hijack DCs for viral dissemination. Binding to DC-SIGN protects HIV-1 from antigen processing and facilitates its transport to lymphoid tissues, where DC-SIGN promotes HIV-1 infection of T cells. Recent studies demonstrate that DC-SIGN is a universal pathogen receptor that also recognizes Ebola, cytomegalovirus and mycobacteria. Mycobacterium tuberculosis targets DC-SIGN by a mechanism that is distinct from that of HIV-1, leading to inhibition of the immunostimulatory function of DC and, hence, promotion of pathogen survival. A better understanding of DC-SIGN-pathogen interactions and their effects on DC function should help to combat infections.

Cell Adhesion Molecules↗