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Serotypes, antimicrobial susceptibility, and beta-lactam resistance mechanisms of clinical Haemophilus influenzae isolates from Bulgaria in a pre-vaccination period.
Scand J Infect Dis 2013; 45(2):81-7SJ

Abstract

OBJECTIVE

To determine the serotypes, antimicrobial susceptibility, and beta-lactam resistance mechanisms of Haemophilus influenzae strains isolated from invasive and respiratory tract infections (RTIs) prior to the introduction of Haemophilus influenzae type b (Hib) vaccination in Bulgaria.

METHODS

A total of 259 isolates were serotyped by polymerase chain reaction. Susceptibility to antibiotics and beta-lactamase production were determined, and DNA sequencing of the ftsI gene was performed for ampicillin non-susceptible strains.

RESULTS

The invasive H. influenzae infections in children were mainly due to serotype b (94.5% in meningitis and 88.9% in other invasive cases). Non-typeable strains (97.4%) were the most frequently found H. influenzae strains in RTIs both in children and adults. Non-susceptibility to ampicillin occurred in 22% of all strains. Ceftriaxone and levofloxacin were the most active agents tested. Ampicillin resistance occurred in 34.4% of invasive strains, and beta-lactamase production was the only mechanism found. Among respiratory tract isolates, ampicillin non-susceptible strains (18%) were classified into the following groups: beta-lactamase-positive, ampicillin-resistant (BLPAR) strains (7.2%); beta-lactamase-negative, ampicillin-non-susceptible (BLNAR) strains (8.2%); and beta- lactamase-positive, amoxicillin-clavulanate-resistant (BLPACR) strains (2.6%). Among 21 BLNAR and BLPACR strains there were 9 different patterns of multiple-amino acid substitutions in penicillin-binding protein 3. Of these, most isolates (81.0%) belonged to group II, defined by the Asn526Lys substitution.

CONCLUSIONS

Beta-lactamase production was more common among invasive strains than in respiratory isolates. BLNAR and BLPACR H. influenzae were found only among respiratory tract isolates.

Authors+Show Affiliations

Department of Medical Microbiology, Faculty of Medicine, Medical University of Sofia, Sofia, Bulgaria. lenasetchanova@hotmail.comNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

22992181

Citation

Setchanova, Lena Petrova, et al. "Serotypes, Antimicrobial Susceptibility, and Beta-lactam Resistance Mechanisms of Clinical Haemophilus Influenzae Isolates From Bulgaria in a Pre-vaccination Period." Scandinavian Journal of Infectious Diseases, vol. 45, no. 2, 2013, pp. 81-7.
Setchanova LP, Kostyanev T, Markovska R, et al. Serotypes, antimicrobial susceptibility, and beta-lactam resistance mechanisms of clinical Haemophilus influenzae isolates from Bulgaria in a pre-vaccination period. Scand J Infect Dis. 2013;45(2):81-7.
Setchanova, L. P., Kostyanev, T., Markovska, R., Miloshev, G., & Mitov, I. G. (2013). Serotypes, antimicrobial susceptibility, and beta-lactam resistance mechanisms of clinical Haemophilus influenzae isolates from Bulgaria in a pre-vaccination period. Scandinavian Journal of Infectious Diseases, 45(2), pp. 81-7. doi:10.3109/00365548.2012.710854.
Setchanova LP, et al. Serotypes, Antimicrobial Susceptibility, and Beta-lactam Resistance Mechanisms of Clinical Haemophilus Influenzae Isolates From Bulgaria in a Pre-vaccination Period. Scand J Infect Dis. 2013;45(2):81-7. PubMed PMID: 22992181.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Serotypes, antimicrobial susceptibility, and beta-lactam resistance mechanisms of clinical Haemophilus influenzae isolates from Bulgaria in a pre-vaccination period. AU - Setchanova,Lena Petrova, AU - Kostyanev,Tomislav, AU - Markovska,Rumyana, AU - Miloshev,George, AU - Mitov,Ivan Gergov, Y1 - 2012/09/19/ PY - 2012/9/21/entrez PY - 2012/9/21/pubmed PY - 2013/5/31/medline SP - 81 EP - 7 JF - Scandinavian journal of infectious diseases JO - Scand. J. Infect. Dis. VL - 45 IS - 2 N2 - OBJECTIVE: To determine the serotypes, antimicrobial susceptibility, and beta-lactam resistance mechanisms of Haemophilus influenzae strains isolated from invasive and respiratory tract infections (RTIs) prior to the introduction of Haemophilus influenzae type b (Hib) vaccination in Bulgaria. METHODS: A total of 259 isolates were serotyped by polymerase chain reaction. Susceptibility to antibiotics and beta-lactamase production were determined, and DNA sequencing of the ftsI gene was performed for ampicillin non-susceptible strains. RESULTS: The invasive H. influenzae infections in children were mainly due to serotype b (94.5% in meningitis and 88.9% in other invasive cases). Non-typeable strains (97.4%) were the most frequently found H. influenzae strains in RTIs both in children and adults. Non-susceptibility to ampicillin occurred in 22% of all strains. Ceftriaxone and levofloxacin were the most active agents tested. Ampicillin resistance occurred in 34.4% of invasive strains, and beta-lactamase production was the only mechanism found. Among respiratory tract isolates, ampicillin non-susceptible strains (18%) were classified into the following groups: beta-lactamase-positive, ampicillin-resistant (BLPAR) strains (7.2%); beta-lactamase-negative, ampicillin-non-susceptible (BLNAR) strains (8.2%); and beta- lactamase-positive, amoxicillin-clavulanate-resistant (BLPACR) strains (2.6%). Among 21 BLNAR and BLPACR strains there were 9 different patterns of multiple-amino acid substitutions in penicillin-binding protein 3. Of these, most isolates (81.0%) belonged to group II, defined by the Asn526Lys substitution. CONCLUSIONS: Beta-lactamase production was more common among invasive strains than in respiratory isolates. BLNAR and BLPACR H. influenzae were found only among respiratory tract isolates. SN - 1651-1980 UR - https://www.unboundmedicine.com/medline/citation/22992181/Serotypes_antimicrobial_susceptibility_and_beta_lactam_resistance_mechanisms_of_clinical_Haemophilus_influenzae_isolates_from_Bulgaria_in_a_pre_vaccination_period_ L2 - http://www.tandfonline.com/doi/full/10.3109/00365548.2012.710854 DB - PRIME DP - Unbound Medicine ER -