Asymptomatic colonization of upper respiratory tract by potential bacterial pathogens

Dhakal, Roshan; Sujatha, S.; Parija, Subhash Chandra; Bhat, B. Vishnu

doi:10.1007/s12098-010-0118-x

Cited by 22 publications

(16 citation statements)

References 9 publications

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“…The high resistance (25.5 %) of GAS to tetracycline reported here is comparable to the global rise noticed (Aggarwal et al, 1984;Dhakal et al, 2010;Jain et al, 2008;Lloyd et al, 2007;Ray et al, 2010;Smeesters et al, 2010;Traub & Leonhard, 1997;Zaoutis et al, 1999) that has been assigned to polyclonal dissemination of resistance types, as antibiotic resistance encoded by transposable elements does occur in GAS. GAS resistance (3.9 %) to chloramphenicol and susceptibility to vancomycin reported in this study are similar to results from previous reports (Jain et al, 2008).…”

Section: Discussionsupporting

confidence: 84%

“…Worldwide data suggest an increased resistance of GAS to macrolides, ranging from 0. A Cd E At Cw T C Nv Ak G Throat isolates 11 + 2 2 2 2 2 + 2 2 2 57 2 2 2 + + + 2 2 2 2 85 2 + + 2 2 2 2 2 2 2 Skin isolates 12 2 2 2 2 + 2 + + 2 2 22.8 2 2 2 + 2 2 + 2 2 2 44 2 2 2 + 2 2 2 + 2 2 44 + 2 2 + 2 + 2 2 2 2 44 2 2 + 2 2 2 2 + 2 2 44 2 2 2 + 2 2 2 + 2 2 44 2 2 2 + + + 2 + 2 2 44 2 2 2 2 2 2 2 2 2 2 49 2 2 2 + + + 2 2 2 2 75.1 2 2 2 2 2 + 2 + 2 2 81 2 2 + 2 2 2 2 2 + 2 81 2 2 2 2 2 + 2 + 2 + 85 2 2 2 2 2 + 2 + 2 2 RF isolates 11 2 2 2 2 2 + 2 + 2 2 67 2 2 2 2 2 + 2 + 2 2 Invasive disease isolates 58 2 2 2 2 2 + + 2 2 2 87 2 2 + 2 2 + 2 2 + 2 95 2 2 2 2 2 + 2 + + 2 Rowe et al, 2009;Traub & Leonhard, 1997); a review of Indian literature showed a gradual increase upto 29.4 % up until 2010 (Brahmadathan et al, 2005;Capoor et al, 2006;Dhakal et al, 2010;Lloyd et al, 2007;Mathur et al, 2002). The absence of, or very low, erythromycin resistance among GAS from pharyngitis and RF patients in the present study is quite similar to previous findings (Brahmadathan et al, 2005;Rijal et al, 2009).…”

Section: Discussionmentioning

confidence: 99%

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Antimicrobial susceptibility pattern of beta-haemolytic group A, C and G streptococci isolated from North India

Dhanda

Chaudhary

Toor

et al. 2013

Journal of Medical Microbiology

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The objective of this study was to determine the antibiotic resistance amongst beta-haemolytic streptococci (BHS) from North India. A total of 155 BHS isolates, comprising group A streptococci (GAS) (102), group C streptococci (GCS) (25) and group G streptococci (GGS) (28), collected from patients with pharyngitis, rheumatic fever, skin disease and invasive disease were analysed for their antimicrobial susceptibility to 20 antibiotics using the Kirby-Bauer disc diffusion method. The MICs of penicillin, tetracycline, clarithromycin, azithromycin and erythromycin were also determined using the HiComb test, following the Clinical and Laboratory Standards Institute guidelines. The results showed that 37.4 % of BHS isolates were susceptible to all antibiotics and 19.4 % were highly resistant to tetracycline; however, only 2.6-5.2 % were resistant to macrolides. The tetracycline resistance (P,0.05) of BHS was found to be statistically significant. GAS isolates from different sources of infection also showed statistically significant antibiotic resistance to azithromycin (P50.029). Multi-drug resistance was found irrespective of streptococcal emm types. No association between GAS emm types and drug resistance was seen. MIC determination showed all isolates to be susceptible to the five antibiotics tested, except for two GAS and one GGS isolates that were resistant to clarithromycin, and one GAS skin isolate that was resistant to tetracycline. This study suggests that the variation in antibiotic resistance amongst BHS isolates from North India is independent of the isolation source and emm type distribution, hence emphasizing the need for a longitudinal surveillance in different regions of India.

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Section: Discussionsupporting

confidence: 84%

Section: Discussionmentioning

confidence: 99%

Antimicrobial susceptibility pattern of beta-haemolytic group A, C and G streptococci isolated from North India

Dhanda

Chaudhary

Toor

et al. 2013

Journal of Medical Microbiology

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“…In contrast, only 3.5% of GAS isolates were resistant to tetracycline in Spain (23). However, the current study result was in agreement with the reports on global rise of tetracycline-resistant GAS (26,27). With regard to the resistance gene, the presence of mefA in an erythromycin-susceptible isolate in the current study is not surprising.…”

Section: Discussionsupporting

confidence: 91%

Extremely Low Prevalence of Erythromycin-Resistant Streptococcus pyogenes Isolates and Their Molecular Characteristics by M Protein Gene and Multilocus Sequence Typing Methods

Kalgo

Jasni

Hadi

et al. 2018

Jundishapur J Microbiol

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Background: Group A streptococci (GAS) are notorious bacteria causing a wide variety of clinical manifestations ranging from mild, acute streptococcal pharyngitis to chronic non-suppurative diseases and immunological sequelae. They are further complicated by the global rise on the emergence of macrolide resistance among these bacteria in which several M protein gene (emm) and sequence types are associated with invasive diseases. Objectives: The current study aimed at determining the erythromycin resistance patterns and molecular characteristics of GAS clinical strains by emm and multilocus sequence typing (MLST) methods. Methods: Thirty-five GAS clinical isolates were subjected to antibiotic susceptibility testing by disk diffusion method. The minimum inhibitory concentration (MIC) of erythromycin against GAS by E-test was determined. Clinical and laboratory standards institute (CLSI) guideline was used for the interpretation of results. Detection of ermA, ermB, and mefA genes by polymerase chain reaction (PCR) was performed and emm typing was done by amplification and sequencing of emm genes per standard protocol. Allele and sequence type (ST) of GAS were obtained using the S. pyogenes MLST database. Results: All the isolates were sensitive to erythromycin, penicillin, clindamycin, chloramphenicol, and vancomycin (100%). Resistance to tetracycline was 54.3%. The mefA gene was found in one erythromycin susceptible isolate. No other erythromycin resistance genes were detected in the isolates. Twenty different emm types were found and the most frequent emm types/subtypes detected were emm1, emm18.21, emm28.5, emm97.4, and emm102.2 (each 8.6%). However, no new emm type was detected. A total of 15 sequence types (STs), eight clonal clusters (CCs), and eight singletons were identified among 21 representative isolates. Three isolates exhibited CC1 (ST28/emm1). Conclusions: High susceptibility of GAS isolates against erythromycin could be due to low antibiotic selective pressure in Malaysian clinical settings. High diversity of emm and ST types revealed the heterogenic nature of the strains circulating in Malaysian hospitals. Continuous epidemiological monitoring by molecular typing methods is warranted to improve the management strategies of GAS infections in future.

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“…One hundred and sixty isolates were found to be β-hemolytic (15.28%) and out of these, 92 isolates were identified as GAS. We found a high prevalence of GAS (8.79%) as compared to the previous studies from different regions of India (3% and 2.8% in the northern part and 4.5% in the southern part) [10,17,30]. A potential reason for the discordant data may be explained by our selection of clinical samples collected from patients with symptoms suggestive of GAS infection.…”

Section: Discussioncontrasting

confidence: 59%

Molecular epidemiology and virulence characteristics of prevalent group A streptococci recovered from patients in northern India

Arya

Sharma

Mehta

et al. 2014

J Infect Dev Ctries

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Introduction: In this study, the prevalence of M types of Group A Streptococcus (GAS) in North India, invasive behavior of prevalent M types, and inflammatory immune response by host cells were studied. Methodology: A total of 1,047 clinical samples were collected between 2004 and 2010. Confirmation of GAS was determined by serotyping and M types were identified by emm gene sequencing. The most prevalent serotypes were selected to study their invasive behavior and inflammatory immune response under different temperatures and salt concentrations in A549 and HEp-2 cells. Results: Ninety-two isolates were identified as GAS of which 17 were M types with 18.5% heterogeneity. The most prevalent M types were M1 (21.73%) and M49 (8.7%), respectively. M1 and M49 were used to study virulence potential and inflammatory immune responses. The efficiency of cell infection decreased with increased temperature for both M types, increasing with lowering temperatures compared to the uninfected control (37°C). As salt concentration was increased, cell infection efficiency was lowered with some exceptions; the infection efficiency of M1 strain in A549 cells with 0.6 M NaCl was 50 fold higher (p ≤ 0.03). Significantly increased production of IL-6 and IL-8 was observed in both cell lines infected with GAS and when grown under different environmental conditions compared to uninfected cell lines. Conclusions: This study determined the prevalence of different M types in North India and showed that environmental conditions can regulate cell infection by GAS . This information may influence the selection of GAS serotypes used in vaccine development.

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Asymptomatic colonization of upper respiratory tract by potential bacterial pathogens

Abstract: S. pneumoniae carriage rate was comparatively higher in the Community and its antimicrobial resistance is an issue to address.

Cited by 22 publications

References 9 publications

Antimicrobial susceptibility pattern of beta-haemolytic group A, C and G streptococci isolated from North India

Antimicrobial susceptibility pattern of beta-haemolytic group A, C and G streptococci isolated from North India

Extremely Low Prevalence of Erythromycin-Resistant Streptococcus pyogenes Isolates and Their Molecular Characteristics by M Protein Gene and Multilocus Sequence Typing Methods

Molecular epidemiology and virulence characteristics of prevalent group A streptococci recovered from patients in northern India

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