Streptococcus pyogenes vulvovaginitis in children in Nottingham

Group A Streptococcus adaptation to diverse niches: lessons from transcriptomic studies

Group A Streptococcus (GAS) is a major human pathogen, causing diseases ranging from mild superficial infections of the skin and pharyngeal epithelium to severe systemic and invasive diseases. Moreover, post infection auto-immune sequelae arise by a yet not fully understood mechanism. The ability of GAS to cause a wide variety of infections is linked to the expression of a large set of virulence factors and their transcriptional regulation in response to various physiological environments. The use of transcriptomics, among others -omics technologies, in addition to traditional molecular methods, has led to a better understanding of GAS pathogenesis and host adaptation mechanisms. This review focusing on bacterial transcriptomic provides new insight into gene-expression patterns in vitro, ex vivo and in vivo with an emphasis on metabolic shifts, virulence genes expression and transcriptional regulators role.

Transcriptomic Analysis of Streptococcus pyogenes Colonizing the Vaginal Mucosa Identifies hupY, an MtsR-Regulated Adhesin Involved in Heme Utilization

Colonization of the host requires the ability to adapt to an environment that is often low in essential nutrients such as iron. Here we present data showing that the transcriptome of the important human pathogen Streptococcus pyogenes shows extensive remodeling during in vivo growth, resulting in, among many other differentially expressed genes and pathways, a significant increase in genes involved in acquiring iron from host heme. Data show that HupY, previously characterized as an adhesin in both S. pyogenes and the related pathogen Streptococcus agalactiae, binds heme and affects intracellular iron concentrations. HupY, a protein with no known heme binding domains, represents a novel heme binding protein playing an important role in bacterial iron homeostasis as well as vaginal colonization.

Streptococcus pyogenes (group A streptococcus [GAS]) is a serious human pathogen with the ability to colonize mucosal surfaces such as the nasopharynx and vaginal tract, often leading to infections such as pharyngitis and vulvovaginitis. We present genome-wide transcriptome sequencing (RNASeq) data showing the transcriptomic changes GAS undergoes during vaginal colonization. These data reveal that the regulon controlled by MtsR, a master metal regulator, is activated during vaginal colonization. This regulon includes two genes highly expressed during vaginal colonization, hupYZ. Here we show that HupY binds heme in vitro, affects intracellular concentrations of iron, and is essential for proper growth of GAS using hemoglobin or serum as the sole iron source. HupY is also important for murine vaginal colonization of both GAS and the related vaginal colonizer and pathogen Streptococcus agalactiae (group B streptococcus [GBS]). These data provide essential information on the link between metal regulation and mucosal colonization in both GAS and GBS.

Antibiotic Resistance of Non-pneumococcal Streptococci and Its Clinical Impact

The taxonomy of streptococci has undergone major changes during the last two decades. The present classification is based on both phenotypic and genotypic data. Phylogenetic classification of streptococci is based on 16S rRNA sequences [1], and it forms the backbone of the overall classification system of streptococci. Phenotypic properties are also important, especially for clinical microbiologists. The type of hemolysis on blood agar, reaction with Lancefield grouping antisera, resistance to optochin, and bile solubility remain important for grouping of clinical Streptococcus isolates and therefore treatment options [2]. In the following chapter, two phenotypic classification groups, viridans group streptococci (VGS) and beta-hemolytic streptococci, will be discussed.

Interactions of Lactobacilli with pathogenic Streptococcus pyogenes

Objective. To determine whether (1) a decreased concentration of Lactobacilli allows S. pyogenes to grow; (2) S. pyogenes is able to grow in the presence of healthy Lactobacillus concentrations; (3) S. pyogenes is capable of inhibiting Lactobacilli. Methods. One hundred fifty patient samples of S. pyogenes were mixed with four different concentrations of L. crispatus and L. jensenii. Colony counts and pH measurements were taken from these concentrations and compared using t-tests and ANOVA statistical analyses. Results. Statistical tests showed no significant difference between the colony counts of S. pyogenes by itself and growth when mixed with Lactobacilli, and no significant difference between the colony counts of S. pyogenes in the four different concentrations of Lactobacilli. Conclusion. The statistical data representing the growth of these two organisms suggests that Lactobacilli did not inhibit the growth of S. pyogenes. Also, S. pyogenes did not inhibit the growth of Lactobacilli.

Pediatric vulvovaginal disorders: a diagnostic approach and review of the literature

Vulvovaginal complaints in the prepubertal child are a common reason for referral to the health care provider. The Cochrane Library and Medline databases were searched for articles published in English from 1980 to December 2004 relating to vulvovaginal conditions in girls. The following search terms were used: vulvovaginitis, prepubertal, pediatric, lichen sclerosis, labial fusion, labial adhesion, genital ulcers, urethral prolapse, psoriasis, and straddle injuries. The objectives of this article are to review the normal vulvovaginal anatomy, describe how to perform an age-appropriate examination, and discuss common vulvovaginal disorders and their management in young girls.

Antibiotic Resistance of Non-Pneumococcal Streptococci and Its Clinical Impact

Viridans streptococci (VGS) form a phylogenetically heterogeneous group of species belonging to the genus Streptococcus (1). However, they have some common phenotypic properties. They are alfa- or non-haemolytic. They can be differentiated from S. pneumoniae by resistance to optochin and the lack of bile solubility (2). They can be differentiated from the Enterococcus species by their inability to grow in a medium containing 6.5% sodium chloride (2). Earlier, so-called nutritionally variant streptococci were included in the VGS but based on the molecular data they have now been removed to a new genus Abiotrophia (3) and are not included in the discussion below. VGS belong to the normal microbiota of the oral cavities and upper respiratory tracts of humans and animals. They can also be isolated from the female genital tract and all regions of the gastrointestinal tract (2, 3). Several species are included in VGS and are listed elsewhere (2, 3). Clinically the most important species belonging to the VGS are S. mitis, S. sanguis and S. oralis.

Group A Streptococcus vulvovaginitis in breastfeeding women

Group A beta-hemolytic streptococcus-associated vulvovaginitis is uncommon in adult women. Clinicians should include group A beta-hemolytic streptococcus as a possible cause of vulvovaginal symptoms in breastfeeding women. Along with appropriate antibiotic therapy, vaginal estrogen therapy may be considered to diminish susceptibility to recurrent infection in women with vaginal atrophy.

Genetic diversity among type emm28 group A Streptococcus strains causing invasive infections and pharyngitis

Genome sequencing of group A Streptococcus (GAS) has revealed that prophages account for the vast majority of gene content differences between strains. Serotype M28 strains are a leading cause of pharyngitis and invasive infections, but little is known about genetic diversity present in natural populations of these organisms. To study this issue, population-based samples of 568 strains from Ontario, Canada; Finland; and Houston, Texas, were analyzed. Special attention was given to analysis of variation in prophage-encoded virulence gene content by a PCR-based method. Thirty and 29 distinct prophage-encoded virulence gene profiles were identified among pharyngitis and invasive infection isolates. Thirteen profiles, representing the majority of the strains, were shared between these two classes of isolates. Significant differences were observed in the frequency of occurrence of certain prophage toxin gene profiles and infection type. M28 strains are highly diverse in prophage-encoded virulence gene content and integration site, supporting the key concept that prophages are critical contributors to GAS genetic diversity and population biology. Nucleotide sequence variation in the emm gene (encodes M protein) was also examined. Only three allelic variants were identified in the hypervariable portion of the emm28 gene. All but one strain had the same inferred amino acid sequence in the first 100 amino acids of the mature M28 protein. In contrast, size differences in the emm28 gene and inferred protein due to variable numbers of C-terminal repeats were common. The presence of macrolide resistance genes (mefA, ermB, and ermTR) was analyzed by PCR, and less than 2% of the strains were positive.

Vulvovaginitis in prepubertal girls

This retrospective study evaluated the clinical features and findings in bacterial cultures and in microscopic examination of vaginal secretions in 80 prepubertal girls, aged 2-12 years, with vulvovaginitis. Vaginal secretions were obtained directly from the vagina with a sterile catheter carefully inserted into the vagina. Pathogenic bacteria were isolated in 36% of cases. In 59% of these cases the isolated pathogen was group A beta-haemolytic streptococcus. Candida was not found in any of the patients. The finding of leucocytes in vaginal secretions as an indicator for growth of pathogenic bacteria had a sensitivity of 83% and a specificity of 59%. Antimicrobial treatment should therefore be based on bacteriological findings of vaginal secretions and not on the presence of leucocytes alone.

Clinical and microbiological features of Haemophilus influenzae vulvovaginitis in young girls

AIMS

To define the clinical and microbiological features of vulvovaginitis in prepubertal girls whose genital swabs yielded Haemophilus influenzae.

METHODS

Laboratory based study and retrospective collection of clinical data from the requesting doctors.

RESULTS

Thirty eight isolates of non-capsulate Haemophilus influenzae and one of H parainfluenzae were isolated from 32 girls aged 18 months to 11 years. No other pathogens, such as beta haemolytic streptococci or yeasts, were present with H influenzae. The most common biotype was biotype II, comprising 57% of the 26 isolates biotyped. Six children had more than one episode of vulvovaginitis caused by H influenzae and a total of 14 children had recurrent vaginal symptoms.

CONCLUSION

Children who have H influenzae vulvovaginitis are at risk of recurrent symptoms. Biotype II is the one most commonly associated with this condition.

Bacteraemic Streptococcus pyogenes infection in the peri-partum period: now a rare disease and prior carriage by the patient may be important

OBJECTIVES

To describe the features of invasive peri-partum Streptococcus pyogenes infection as it occurs in current day practice in North Yorkshire.

METHODS

The case and laboratory records of all mothers and/or babies with detected S. pyogenes bacteraemia in the Harrogate and Northallerton districts of North Yorkshire (combined catchment population 260 000) were reviewed for the 20 years 1980-99. An additional bacteraemic case occurring recently in the York district was included.

RESULTS

In six recorded episodes, both mother and baby were affected in three, mother only in two and baby only in one. The incidence of detected infection was one such episode per million population per year, one episode per 11 000 live births and one infected baby per 18 000 live births. Maternal features included endometritis, septicaemia, peritonitis, necrotising fasciitis and toxic shock syndrome while, in babies, infection was manifest by stillbirth or septicaemia, cyanosis, jaundice, lethargy and cellulitis.

CONCLUSION

Peri-partum S. pyogenes infection is rare in North Yorkshire, with a local incidence revealed in this study of 1/million population/year, or 1:11 000 live births. Invasive neonatal infection with S. pyogenes appears to be six times less frequent in this locality than with group B streptococci. Mothers and/or their babies can be affected. Data suggests that some infection is autogenous from streptococci carried in the mother's genital tract. Although data in this setting are currently few, when a mother has suspected invasive group A streptococcal infection we recommend that the newborn child should also receive antibiotics without delay.

Isolation rate, T-serotyping and susceptibility to antibiotics of Group A Streptococcus from pediatric infections in Athens

OBJECTIVE

The epidemiology of Group A Streptococcus (GAS) in Greece is not known. We have therefore conducted this prospective study to investigate the isolation rate of GAS from pediatric specimens, determine T-serotype frequency and examine the susceptibility of GAS to penicillin, erythromycin and clindamycin.

METHODS

Over a 3-year study-period (1993-95) 11 597 clinical specimens obtained from sick children were inoculated on appropriate culture media. The isolation and identification of GAS strains were assessed by conventional methods. T-typing was performed by slide agglutination. Serum opacity factor (OF) was detected by microwell

METHOD

The susceptibility of the strains was tested by the Kirby Bauer method.

RESULTS

GAS were isolated from 1125 out of 11 597 (9.7%) clinical specimens, mostly from throat samples (15.6%). T-serotyping was performed in 652 GAS strains. A significant difference of the incidence of T-serotypes was observed within the 3 years studied (chi2 = 70.3, DF = 18, P < 0.001). The most dominant isolates were T-1 (25%), T-4 (20%) and T-12 (16%) during 1993, 1994 and 1995, respectively. Non-typeable (NT) strains were 4%. OF and hyaluronic acid were produced from 49.8% and 3% of the strains, respectively. All isolated strains were susceptible to penicillin and clindamycin. Resistance to erythromycin was 5.0-8.7% over the 3-year study period.

CONCLUSIONS

There was a wide distribution of GAS T-serotypes in Athens and a significant change in their annual predominance. All strains were susceptible to penicillin and clindamycin, but a low level of erythromycin resistance was observed.

Haemophilus influenzae: an underrated cause of vulvovaginitis in young girls

AIMS

To establish the common pathogens associated with infective vulvovaginitis in young girls in the local population and to determine current management of this condition.

METHODS

A prospective laboratory based survey was carried out over 19 months. A questionnaire was then sent to local general practitioners and hospital doctors.

RESULTS

One hundred and six swabs were received during the study period of which 43 (40.5%) yielded organisms recognised as causes of vulvovaginitis. The most common pathogen was group A beta haemolytic streptococcus (19), with Haemophilus influenzae the second most common (11). Candida was isolated on nine occasions. The users' questionnaire had an overall response rate of 52%. Forty one per cent of respondents nominated candida as the most common cause of this condition. Forty six per cent were aware that beta haemolytic streptococci caused juvenile vulvovaginitis, but only four (3.6%) knew that H influenzae was a possible pathogen. The most popular agent for empirical treatment of vulvovaginitis was topical clotrimazole cream, although 24 respondents (22%) prescribed antibiotics that are active against both group A beta haemolytic streptococci and H influenzae.

CONCLUSIONS

Although H influenzae is the second most common infective cause of juvenile vulvovaginitis in the local population, most doctors managing these patients were unaware of its importance and may not be prescribing appropriate empirical treatment.

Streptococcal vulvovaginitis in girls

Group A beta-hemolytic Streptococcus (GAHS) was isolated from 18% of swabs submitted to a district microbiology laboratory from girls with vulvovaginitis, a figure similar to that from a contemporary British study. This suggests that vulvovaginitis is more commonly associated with GAHS than reported previously. This could represent either an increase in frequency of the condition or better recognition of it.

Streptococci and the genital tract

Streptococci of Lancefield Group B (GBS) are known to cause maternal sepsis and neonatal infection, whereas streptococci Lancefield Group A (GAS) cause vulvo-vaginitis in both children and adults. Prevalence of SGB colonization of the lower genital tract of normal women is between 4-18%, with higher rates found in hospital personnel and delivery rooms. Such high carriage rates may be a significant factor in nosocomial transmission of GBS to neonates. Symptomatic infection is uncommon and usually secondary to other pathological states. Amnionitis is a complication of vaginal carriage of GBS and there is now evidence that chorioamnionitis is associated with pre-term labour and its attendant problems. GBS infection of the male genitalia has also been described. Intrapartum chemoprophylaxis has been shown to prevent early onset GBS disease of the neonate. Prevalence of GAS in the genital tract is lower than that for GBS, but is more likely to be symptomatic. The response to penicillin is usually prompt. Optimal drug regimens need to be determined, particularly for use in pregnancy.