Antimicrobial resistance trends in blood culture positive Salmonella Typhi isolates from Pondicherry,India, 2005–2009

Typhoid fever is caused by Salmonella enterica serovar Typhi, a major public health concern in developing countries. Recently, there has been an upsurge in the occurrence of bacterial isolates that are resistant to ciprofloxacin, and the emergence of broad spectrum β-lactamases in typhoidal salmonellae constitutes a new challenge for the clinician. A total of 337 blood culture isolates of S. Typhi, isolated from Pondicherry, India, between January 2005 and December 2009, were investigated using phenotypic, molecular and serological methods. Of the 337 isolates, 74 (22%) were found to be multidrug resistant (MDR) and 264 (78%) nalidixic acid resistant (NAR). Isolates with reduced susceptibility to ciprofloxacin possessed single mutations in the gyrA gene. A high rate of resistance (8%) was found to ciprofloxacin. All isolates with a ciprofloxacin MIC ≥ 4 mg/L possessed both double mutations in the QRDR of the gyrA gene and a single mutation in the parC gene. Active efflux pump mechanisms were also found to be involved in ciprofloxacin resistance. Finally, a large number of PFGE patterns (non-clonal genotypes) were observed among the S. Typhi isolates. In conclusion, a high rate of ciprofloxacin resistance was observed in comparison to other endemic areas in blood culture isolates of S. Typhi from Pondicherry, India, with steadily increasing NAR but decreasing MDR isolations over the study period. This is most likely to be due to an increased use of ciprofloxacin as a first-line drug of choice over more traditional antimicrobial agents for the treatment of typhoid fever.     

Salmonella genomic island 1-J variants associated with change in the antibiotic resistance gene cluster in multidrug-resistant Salmonella enterica serovar Virchow isolated from humans,Taiwan, 2004–2006

Salmonella genomic island 1 (variant SGI1-J3) has been previously identified in multi-drug resistant (MDR) Salmonella enterica serovar Virchow isolated from humans in 1994. In this study, antimicrobial resistance, genotypes and genetic relationship were investigated in 96 S. Virchow isolates collected from humans in 2004–2006. XbaI-PFGE analysis separated 96 isolates into two main related clusters, I and II, which consisted of four major pulsotypes differing in prevalence by year. The majority of isolates were MDR to chloramphenicol, sulfonamide, trimethoprim and tetracyclines associated with antimicrobial resistance genes dfrA1, floR2, sulI and tet(G) of variant SGI1-J3. Among nine variants, we determined two novel variants, SGI1-J4 and -J5, which have undergone different homologous recombinational events resulting in partial deletions of the MDR region. The first one contained an empty integron structure and the second presented a deletion extending from the IS6100 element to the adjacent SGI1 backbone. SGI1-J3 is largely encountered in clonally related MDR S. Virchow isolates collected from humans, which spread vertically. The genomic island SGI1 appears to be largely responsible for the diversity of MDR phenotypes among S. Virchow isolates in Taiwan.     

Antimicrobial resistance among Haemophilus influenzae isolates responsible for lower respiratory tract infections in Poland, 2005–2019

European Journal of Clinical Microbiology & Infectious Diseases - Haemophilus influenzae is a human-specific pathogen responsible for respiratory tract infections, meningitis, and sepsis. The...     

Antimicrobial resistance,presence of integrons and biofilm formation of Salmonella Pullorum isolates from eastern China (1962–2010)

Three hundred and thirty-seven isolates of Salmonella Pullorum from eastern China between 1962 and 2010 were characterized for antimicrobial susceptibility (disk diffusion method), the presence of integrons (polymerase chain reaction followed by sequencing) and the ability to form biofilms (semi-quantitative adherence assay). Two hundred and fifty-eight isolates (76.6%) exhibited multiple drug resistance (MDR; resistant to at least three different classes of antimicrobials), and the level of drug resistance is increasing with time. There were three isolates (9.4%) exhibiting MDR from 1962 to 1968. MDR rates began to increase for isolates between 1970 to 1979 and 1980 to 1987 (64.6 to 78.7%). The MDR rates reached 96.6% for isolates between 1990 and 2010. Polymerase chain reaction screening for integrons showed that 75 isolates (22.3%) were positive for class 1 integrons while none were positive for class 2 integrons. All of the class 1 integron-positive isolates exhibited MDR and were more frequently resistant than the negative isolates. Two hundred and twenty isolates (65.3%) had the ability to form biofilms, and bacterial resistance levels to cefamandole, trimethoprim and trimethoprim/sulfamethoxazole were significantly higher for biofilm-positive groups than the biofilm-negative groups. Our data show that multidrug resistance is common among S. Pullorum isolated from eastern China, being more frequent after 1990 than before 1990, and the presence of class 1 integrons is associated with multidrug resistance.     

Persistent high macrolide resistance rate and increase of macrolide-resistant ST14 strains among Mycoplasma pneumoniae in South Korea, 2019–2020

BackgroundExpansion of the single sequence type 3 (ST3) was associated with a high macrolide resistance rate among Mycoplasma pneumoniae in Korea during the 2014–2016 epidemic. This study investigates the macrolide resistance rate and genetic diversity of the subsequent epidemic of M. pneumoniae pneumonia in 2019–2020.MethodsThe culture for M. pneumoniae was developed from 1228 respiratory samples collected from children with pneumonia in four hospitals in Korea between January 2019 and January 2020. Determination of macrolide resistance and multilocus sequence typing analysis were performed on M. pneumoniae isolates. eBURST analysis was applied to estimate the relationships among strains and to assign strains to a clonal complex.ResultsM. pneumoniae was cultured in 93 (7.6%) of 1228 clinical samples. The overall macrolide resistance rate of M. pneumoniae strains was 78.5% (73/93). Of the nine STs identified, three were novel. The most common ST was ST3 (66 [71.0%]) followed by ST14 (18 [19.4%]) and ST7/ST15 (2 [2.2%] each). Three STs (ST3, ST14, and ST17) exhibited macrolide resistance. The macrolide resistance rates of ST3 and ST14 were 98.5% (65 of 66) and 38.9% (7 of 18), respectively.ConclusionCompared to the previous outbreak in 2014–2016, the overall macrolide resistance remained high; however, an increasing proportion of macrolide resistance was observed within ST14 strains in 2019–2020.     

Trends in ESBLs and PABLs among enteric Salmonella isolates from children in Gwangju,Korea: 2014–2018

ObjectivesNon-typhoid Salmonella infection is a major agent of food-borne outbreaks as well as individual cases worldwide. However, few studies on drug-resistant Salmonella strains, especially those recovered from young children, are available. Therefore, we determined the prevalence and characteristics of cephalosporin-resistant Salmonella isolates in the south-west region of Korea over a five-year period.MethodsNon-duplicate Salmonella clinical isolates were recovered from diarrhoeagenic patient specimens at 12 hospitals in Gwangju, Korea between January 2014 and December 2018. Antimicrobial susceptibility testing and molecular features of cephalosporin-resistant isolates were determined.ResultsA total of 652 Salmonella isolates were collected and 48 cefotaxime-resistant Salmonella isolates (7.4%), that belonged to nine Salmonella serovars, were identified. These were S. Enteritidis, S. Typhimurium, S. I 4,[5],12:i:-, S. Virchow, S. Agona, S. Bareilly, S. Infantis, S. Newport, and S. Schleissheim. The prevalence rate increased from 5.3% in 2014 to 10.3% in 2018. S. Virchow (44.4%) showed significantly high resistant rate compared to the other serovars. PGFE genotyping revealed high genetic homogeneities among each Salmonella serovars, suggesting clonal dissemination of cephalosporin-resistant strains.ConclusionsProgressive increases in carriage rates and the possibility of community outbreaks by cephalosporin-resistant Salmonella in young children may pose tangible public health threats.     

A secular trend in invasive non-typhoidal Salmonella in South India, 2000–2020: Identification challenges and antibiogram

PurposeInvasive non-typhoidal Salmonella (iNTS) disease is an important cause of morbidity and mortality in African countries. However, the incidence in Indian subcontinent remains poorly documented. This study has assessed the incidence of iNTS in India with a perspective on its AMR profiles and serovar distribution for a period of 21 years from 2000 to 2020 from a tertiary care centre in South India.MethodsA total of 461 iNTS isolates were subjected to serotyping and antimicrobial susceptibility testing (AST). A subset of isolates was genotyped by multi locus sequence typing (MLST) and results were compared to serotyping to predict the accuracy.ResultsOverall, 461 iNTS isolates were characterised mostly comprising of S. Typhimurium (49.2%) and S. Enteritidis (28.8%). Proportion of isolates resistant to first line antibiotics such as ampicillin, chloramphenicol and trimethoprim/sulphamethoxazole were 6.7%, 1.7% and 3.6% respectively. Isolates resistant to third generation cephalosporin are at a gradual rise while decreased susceptibility to quinolones was most common. The incidence of iNTS infection was maximum in the age group of >15 years. MLST analysis showed discrepancies in assigning the serovars by serotyping as three S. Saintpaul were identified as S. Typhimurium.ConclusionThe clinical epidemiology, serovar distribution and antimicrobial susceptibility patterns of invasive Salmonella isolates from India suggest that there is only a small burden of iNTS disease. However the gradual emergence of AMR in iNTS isolates indicates serious risk for public health warranting the importance enhanced molecular surveillance.     

The clinical implication of serotype distribution and drug resistance of invasive pneumococcal disease in children: A single center study in southern Taiwan during 2010–2016

BackgroundThe regional study of pediatric invasive pneumococcal disease (IPD) is still limited in Taiwan. The aim of this study is to update the epidemiologic data of pediatric IPD in Taiwan, focusing on the trend of non-13-valent pneumococcal conjugate vaccines (PCV13)-specific serotypes and antimicrobial susceptibility.MethodsThis was a single-center retrospective study by chart reviewing and recruited patients aged <18 years who were reported having IPD between January 2010 and December 2016. Clinical manifestations, serotypes of pneumococcus and antimicrobial susceptibility were compared and analyzed.ResultsA total of 46 patients were enrolled in this study. Serotype 19 A was the most common serotype (32.6%) in pediatric IPD and significantly correlated with empyema. Non-PCV13-specific serotypes such as serotype 15, 15B, 15C and 22 were reported during this period. There was no mortality or significant morbidity associated with these emerging strains. Using the meningitis breakpoint of minimum inhibitory concentration (MIC), although it showed no significant linear trend of the prevalence of ceftriaxone non-susceptible pneumococcus (CNSP) (p = 0.392), the prevalence of CNSP increased from 50% (11 over 22) before 2013 to 83% (20 over 24) after 2013 with statistical significance (p = 0.027).ConclusionThe increase in the prevalence of CNSP using meningitis breakpoint was observed since 2013. For treating pneumococcal meningitis, empirical therapy with vancomycin and ceftriaxone is warranted. Although the non-PCV13-specific serotypes reported in our study caused no morbidity and mortality, further monitoring and surveillance are still recommended.     

Prevalence and characterization of extended-spectrum β-lactamase-producing clinical Salmonella enterica isolates in Dakar,Senegal, from 1999 to 2009

A total of 1623 clinical isolates of Salmonella belonging to 229 serotypes were received by the Senegalese Reference Center for Enterobacteria from January 1999 to December 2009. The most common serotypes were Enteritidis (19% of the isolates), Typhi (8%), Typhimurium (7%) and Kentucky (4%). A significant increase in the prevalence of resistance to amoxicillin (0.9% in 1999 to 11.1% in 2009) and nalidixic acid (0.9% in 1999 to 26.7% in 2009) was observed in non-typhoidal Salmonella serotypes. For critically important antibiotics, notably ciprofloxacin and extended-spectrum cephalosporins (ESCs), the rates of resistance were low: 0.3% and 0.5%, respectively. Seven ESC-resistant Salmonella strains and three additional ESC-resistant strains from Senegal (1990) and Mali (2007) were studied to identify the genetic basis of their antibiotic resistance. All ESC-resistant strains produced an extended-spectrum β-lactamase (ESBL). These were CTX-M-15 (n = 6; 2000–2008), SHV-12 (n = 3; 2000–2001) and SHV-2 (n = 1; 1990). A large IncHI2 ST1 pK29-like plasmid was found in six strains (three producing SHV-12 and three CTX-M-15), whereas IncN and IncF plasmids were found in three strains and one strain, respectively. The association of plasmid-mediated quinolone resistance (PMQR) genes qnrB1 and aac(6′)-Ib-cr was found in four ESBL-producing strains, leading to decreased susceptibility and even full resistance to ciprofloxacin (MIC range 0.75–2 mg/L) despite the absence of mutations in the quinolone resistance-determining region (QRDR) of gyrA, gyrB, parC and parE. This association of ESBL and multiple PMQR mechanisms within the same strains is therefore a serious concern as it hampers the use of both ESCs and fluoroquinolones for severe Salmonella infections.     

Characterisation of foot-and-mouth disease virus strains circulating in Turkey during 1996–2004

Summary. Two genotypes of foot-and-mouth disease virus serotype A were identified as the cause of disease outbreaks in Turkey during 1996–2004, while serotype O strains, identified during the same period, seem to represent an evolutionary continuum, and Asia1 strains were only rarely identified. The data presented are concordant with the conclusion that serotype A strains are repeatedly introduced to Turkey from the east and circulate only transiently in farming communities, while type O strains persist and re-emerge from endemic areas of Turkey. The co-circulation of strains belonging to two A genotypes for 6 years, as observed in the present study, is a remarkable difference compared to previous decades in which only one A genotype was transiently circulating, successively being replaced by others. This co-circulation was observed in spite of enforcement countrywide of biannual vaccination of more than 50% of the cattle during the same period. Mean r₁ values of 0.70 ± 0.19 and 0.39 ± 0.04 found for A96 and A99 isolates, respectively, compared to the A96 vaccine component reveal antigenic differences but also imply that the vaccine in use in Turkey should provide protection against both genotypes. It is suggested that further studies to reveal the nature of the difference in epidemiological dynamics of type A and type O strains might lead to an understanding of the measures required to control foot-and-mouth disease in islands of persistent circulation.     

CpG oligonucleotides and recombinant interferon-γ in combination improve protection in chickens to Salmonella enterica serovar Enteritidis challenge as an adjuvant component,but have no effect in reducing Salmonella carriage in infected chickens

Salmonella enterica serovar Enteritidis is the most common cause of human salmonellosis in many developed nations. It is frequently associated with both poultry meat and eggs. In the present study we have determined whether CpG oligonucleotides that stimulate the immune system via Toll like-receptors 15 and 21 in the chicken can be used as immunomodulatory agents to break carriage of S. Enteritidis in in vitro and in vivo infection models. We also investigated its use as a component in an adjuvant to stimulate cell mediated immunity with a killed vaccine preparation. Following infection of the chicken macrophage-like cell line HD11 with Salmonella enterica serovar Gallinarum, cells were stimulated with an oligonucleotide containing a CpG motif, or with a non-CpG oligonucleotide control at concentrations ranging from 0 to 80 µM. Addition of the CpG oligonucleotide greatly enhanced clearance of S. Enteritidis in dose-dependent manner, whilst the control oligonucleotide had no significant effect. In contrast, stimulation of cells infected with S. Gallinarum had no effect. The CpG or control oligonucleotide with recombinant chicken interferon-γ was administered intramuscularly into chickens experimentally colonized with S. Enteritidis, although neither preparation produced any change in intestinal colonization levels to that in untreated control birds. Finally, CpG oligonucleotides were incorporated with recombinant interferon-γ, double-stranded RNA (Poly I:C) and squalene as a Th1-stimulating combined adjuvant for synergistic activation of cellular immunity (CASAC) together with whole killed Salmonella as the antigen as an experimental vaccine. Following vaccination and challenge of chickens with S. Enteritidis, CASAC gave significant protection to intestinal colonization whereas the same antigen given with a proprietary adjuvant did not. Neither adjuvant increased protection to systemic infection. The data suggest that adjuvants incorporating CpG motifs and interferon-γ may improve protection afforded by killed-Salmonella vaccines.     

Changes in epidemiology and antimicrobial susceptibility of nontyphoid Salmonella in children in southern Taiwan, 1997–2016

BackgroundThis study aimed to investigate the changing trends in serogroup distribution and antimicrobial susceptibility of nontyphoid Salmonella (NTS) isolated from children in the past two decades in Taiwan.MethodsThis retrospective study enrolled patients aged younger than 18 years with culture-proven NTS infection in a tertiary medical center from 1997 to 2016. Data on age, Salmonella serogroup, culture sample, and antimicrobial susceptibility were obtained from medical records. The rates of Salmonella serogroups and antimicrobial resistance were compared between period 1 (1997–2006) and period 2 (2007–2016).ResultsA total of 2075 NTS isolates were identified from 1997 to 2016 (1036 in period 1, 1039 in period 2). The major isolates were from feces (89.1%) and blood (10.4%). The most common serogroup was serogroup B (54.8%), followed by serogroup D (18.8%). There was a significant decline in the proportion of serogroup B with a concomitant rise in serogroup D in the past two decades. In period 2, resistance to cefotaxime and cefixime increased remarkably among serogroup B, whereas resistance to ampicillin increased notably among serogroup D. Furthermore, the incidence of multidrug-resistant (≥3 antibiotics) NTS significantly decreased in both serogroup B and serogroup D in period 2.ConclusionThis study revealed a significant rise in serogroup D with a concomitant decline in serogroup B NTS infection in Taiwanese children. Moreover, antimicrobial resistance to third-generation cephalosporins increased in serogroup B. Continuous surveillance of NTS serogroup distribution and antimicrobial susceptibility is mandatory to formulate therapeutic strategies for NTS infections.     

Rain,temperature, and child–adolescent height among Native Amazonians in Bolivia

Background: Global climate change and recent studies on early-life origins of well-being suggest that climate events early in life might affect health later in life.

Aim: The study tested hypotheses about the association between the level and variability of rain and temperature early in life on the height of children and adolescents in a foraging–farming society of native Amazonians in Bolivia (Tsimane').

Subject and methods: Measurements were taken for 525 children aged 2–12 and 218 adolescents aged 13–23 in 13 villages in 2005. Log of standing height was regressed on mean annual level and mean intra-annual monthly coefficient of variation (CV) of rain and mean annual level of temperature during gestation, birth year, and ages 2–4. Controls include age, quinquennium and season of birth, parent's attributes, and dummy variables for surveyors and villages.

Results: Climate variables were only related with the height of boys age 2–12. The level and CV of rain during birth year and the CV of rain and level of temperature during ages 2–4 were associated with taller stature. There were no secular changes in temperature (1973–2005) or rain (1943–2005).

Conclusion: The height of young females and males is well protected from climate events, but protection works less well for boys ages 2–12.     

Self-reported sleep patterns, sleep problems, and behavioral problems among school children aged 8–11 years

Objectives

Investigation of sleep patterns, sleep problems, and behavioral problems in 8- to 11-year-old children.

Methods

A total of 330 children (age: M=9.52; SD=0.56; range=8–11 years; 47.3% girls) in the 4th grade of elementary school in Salzburg (Austria) completed a self-report questionnaire (80 items) to survey sleep patterns, sleep problems, and behavioral problems.

Results

Children aged 8–11 years slept approximately 10 h and 13 min on school days (SD=47 min) as well as on weekends (SD=81 min); girls slept significantly longer on weekends than boys. Most common self-reported sleep problems were dryness of the mouth (26.6%), sleep onset delay (21.9%), bedtime resistance (20.3%), and restless legs (19.4%). There was a significant association between watching TV as well as playing computer games prior to sleep with frightful dreams. Daytime sleepiness indicated by difficulty waking up (33.4%) and having a hard time getting out of bed (28.5%) was also very prominent. However, children in Salzburg seemed to be less tired during school (6.6%) or when doing homework (4.8%) compared to other nationalities. Behavioral problems (e.g., emotional symptoms, hyperactivity and inattention, conduct problems, peer problems) and daytime sleepiness were both significantly associated with sleep problems: the more sleep problems reported, the worse behavioral problems and daytime sleepiness were. Moreover, we could show that sharing the bed with a pet was also related to sleep problems.

Conclusions

Self-reported sleep problems among 8- to 11-year-old children are very common. There is a strong relationship between sleep disorders and behavioral problems. Routine screening and diagnosis as well as treatment of sleep disorders in school children should, therefore, be established in the future.     

Seroprevalence distribution of Aichi virus among a French population in 2006–2007

Little is known about the epidemiology of Aichi virus, which is a new member of the family Picornaviridae, in the genus Kobuvirus. We report here on seroprevalence in France. Sera were screened using an enzyme-linked immunosorbent assay (ELISA) for immunoglobulin G. Of 972 sera tested, seroprevalence ranged from 25% for the 7-month-to-9-year-old age group to about 85% for the 30-to-39-year-old age group and older age groups. Our ELISA correlated well with the microneutralization technique. This study shows that Aichi virus is quite frequent in France and that seroconversion occurs before the age of 40.     

Human IgG isotypes and activating Fcγ receptors in the interaction of Salmonella enterica serovar Typhimurium with phagocytic cells

Several classes and multiple subclasses of immunoglobulins are produced towards protein and polysaccharide antigens in response to Salmonella infection and play a key role in protection against systemic disease. The targeting of Salmonella to Fc receptors (FcR) on phagocytes is a key step in the antibody-mediated antibacterial functions of host cells. We wished to compare the relative efficiency of different human IgG subclasses, which targeted the Salmonella enterica OmpA surface protein in modulating the interaction of bacteria with human phagocytes. To this end, we developed a novel system by tagging OmpA with a foreign CD52 mimotope (TSSPSAD) and opsonizing the bacteria with a panel of humanized CD52 antibodies that share the same antigen-binding V-region, but have constant regions of different subclasses. Our data revealed that opsonization with all the IgG subclasses increases Salmonella uptake by human phagocytes. IgG3 resulted in the highest level of bacterial uptake and the highest average bacterial load per infected cell, which was closely followed by IgG1, then IgG4 and lastly IgG2. Phagocytosis mediated by IgG1, IgG3 and IgG4 had a higher dependency on FcγRI than FcγRIIA, whereas IgG2-mediated phagocytosis required FcγRIIA more than FcγRI. The results show that IgG binding to OmpA increases the uptake of Salmonella by human phagocytic cells and that the efficiency of this process depends both on the subclass of the IgG and the type of FcR that is available for antibody binding.