Beta-lactam resistance: clinical implications for pediatric patients

Prevalence and characterization of Listeria monocytogenes isolated from pork meat and on inert surfaces

This study focuses on the prevalence of Listeria monocytogenes (Lm) in pork meat and on inert surfaces from slaughterhouses in Sonora, Mexico. A total of 21 Lm were obtained from 103 samples, giving a prevalence of 20.3%. The prevalence of Lm in pork loin was 15.9% and 20.8% for inert surfaces in Federal Inspection Type (FIT) slaughterhouses. For non-FIT slaughterhouses, the prevalence was 25.7%. PCR amplification of genomic DNA from the Lm isolates revealed the presence of the hlyA gene, suggesting a pathogenic nature for these isolates. The isolates obtained in this work all clustered with Lm, according to our phylogenetic analysis based on the 16S rDNA sequence. This Lm cluster indicates that Lm isolates 7-2, 4, 2-1, 10B, 8, 3, 3-3, and 9 share 16S rRNA identity with other Lm isolates that have been reported as foodborne pathogens (rR2-502, J1817, J1816, J1926) and that are involved in foodborne outbreaks. The most commonly detected serotypes were 1/2a and 1/2b. All isolates displayed differential responses to the assayed antibiotics, and most isolates were able to grow in the presence of penicillin G, or both penicillin and penicillin-derived (oxacillin) antibiotics.

Coexistence of blaOXA48 and aac(6′)-Ib-cr Genes in Klebsiella Pneumoniae Isolates from Istanbul, Turkey

This study evaluated the presence of carbapenem hydrolysing β-lactamase genes and plasmid-mediated quinolone resistance (PMQR) determinants in 22 Klebsiella pneumoniae isolates collected from the Istanbul Medical Faculty, Turkey, which reduced the susceptibility or resistance to carbapenem. The VITEK® 2 system and E-tests were used to determine the minimum inhibitory concentrations needed to inhibit bacterial growth. Genes were screened by polymerase chain reaction, and gene transferability was evaluated by transconjugation. Strain clonality was investigated by pulsed-field gel electrophoresis (PFGE). All strains were OXA-48 β-lactamase producers and three (13.6%) were also positive for the aac(6′)-Ib-cr gene. Most of the strains harboured other b-lactamase (bla) genes such as blaTEM, blaSHV, blaCTX-M and blaVEB-1. The transconjugants mostly harboured blaOXA-48 and other β-lactamases separately. PFGE revealed eight pulsotypes among the isolates. The coexistence of blaOXA-48 and PMQR in K. pneumoniae isolates may present a significant threat to health, especially in the nosocomial setting.

Ketolides in the treatment of community-acquired respiratory tract infections: A review

BACKGROUND

The increasing prevalence of resistance to established antibiotics among key respiratory bacterial pathogens highlights a need for new antibacterial agents for the treatment of community-acquired respiratory tract infections (RTIs). Ketolides are a new class of antibiotics specifically developed for the treatment of RTIs.

OBJECTIVE

The aim of this review was to present the current status of treatment of RTIs with ketolides, focusing on telithromycin-the first ketolide to be approved by the US Food and Drug Administration for clinical use.

METHODS

TO GATHER EVIDENCE ON THE CURRENT STATUS OF KETOLIDES, A LITERATURE SEARCH WAS CONDUCTED USING MEDLINE (YEARS: 1990-2005; key terms: ketolides, telithromycin, and HMR3647).

RESULTS

Telithromycin shows strong in vitro activity against the major respiratorypathogens, including strains resistant to other antibiotics, as well as the atypical respiratory pathogens. The pharmacokinetic properties of telithromycin are compatible with once-daily dosing. Clinical trials have demonstrated that telithromycin 800 mg QD for 5 to 10 days is effective in the treatment of acute bacterial sinusitis, acute bacterial exacerbations of chronic bronchitis, and mild to moderate community-acquired pneumonia. Overall, telithromycin is well tolerated by patients. Drug-drug interactions are similar to those reported for macrolides.

CONCLUSION

Evidence to date indicates that telithromycin is an effective andwell-tolerated empiric treatment for community-acquired RTIs.

Physician behaviour for antimicrobial prescribing for paediatric upper respiratory tract infections: a survey in general practice in Trinidad, West Indies

Background

Upper respiratory tract infections (URTIs) are among the most frequent reasons for physician office visits in paediatrics. Despite their predominant viral aetiology, URTIs continue to be treated with antimicrobials. We explored general practitioners' (GPs) prescribing behaviour for antimicrobials in children (≤ 16 years) with URTIs in Trinidad, using the guidelines from the Centers for Disease Control and Prevention (CDC) as a reference.

Methods

A cross-sectional study was conducted on 92 consenting GPs from the 109 contacted in Central and East Trinidad, between January to June 2003. Using a pilot-tested questionnaire, GPs identified the 5 most frequent URTIs they see in office and reported on their antimicrobial prescribing practices for these URTIs to trained research students.

Results

The 5 most frequent URTIs presenting in children in general practice, are the common cold, pharyngitis, tonsillitis, sinusitis and acute otitis media (AOM) in rank order. GPs prescribe at least 25 different antibiotics for these URTIs with significant associations for amoxicillin, co-amoxiclav, cefaclor, cefuroxime, erythromycin, clarithromycin and azithromycin (p < 0.001). Amoxicillin alone or with clavulanate was the most frequently prescribed antibiotic for all URTIs. Prescribing variations from the CDC recommendations were observed for all URTIs except for AOM (50%), the most common condition for antibiotics. Doctors practicing for >30 years were more likely to prescribe antibiotics for the common cold (p = 0.014). Severity (95.7%) and duration of illness (82.5%) influenced doctors' prescribing and over prescribing in general practice was attributed to parent demands (75%) and concern for secondary bacterial infections (70%). Physicians do not request laboratory investigations primarily because they are unnecessary (86%) and the waiting time for results is too long (51%).

Conclusions

Antibiotics are over prescribed for paediatric URTIs in Trinidad and amoxicillin with co-amoxiclav were preferentially prescribed. Except for AOM, GPs' prescribing varied from the CDC guidelines for drug and duration. Physicians recognise antibiotics are overused and consider parents expecting antibiotics and a concern for secondary bacterial infections are prescribing pressures. Guidelines to manage URTIs, ongoing surveillance programs for antibiotic resistance, public health education on non-antibiotic strategies, and postgraduate education for rational pharmacotherapy in general practice would decrease inappropriate antibiotic use in URTIs.

Management of recurrent and persistent acute otitis media: new options with familiar antibiotics

Recurrent and persistent acute otitis media (AOM) is a common problem, affecting close to 20% of children in their first years of life. It presents a therapeutic challenge to physicians, particularly as beta-lactamase-producing Haemophilus influenzae, as well as penicillin- and, more recently, macrolide-resistant Streptococcus pneumoniae are often responsible for AOM in these patients. Intramuscular ceftriaxone (50 mg/kg, once daily for 3 days) has been shown to be effective in treating nonresponsive AOM, but there have been relatively few clinical trials exploring oral antibiotic regimens. Higher doses of commonly used antibiotics (amoxicillin-clavulanate ratio, 14:1 ratio and azithromycin 60 mg/kg divided into three equal once daily doses) have demonstrated high rates of clinical success. These studies will be discussed together with a review of the clinical and microbiologic characteristics of this disease. We will also address the impact that the pneumococcal conjugate vaccine may have on the microbiology of recurrent and persistent AOM.

Survey of methicillin-resistant Staphylococcus aureus from neonates and the environment in the NICU

Methicillin-resistant Staphylococcus aureus (MRSA) is a risk factor of nosocomial infection with compromised hosts including neonates. Currently, the prevalence of MRSA carriers among children is increasing in Japan. There are some reports of nosocomial infection caused by MRSA in a pediatric ward or neonatal intensive care unit (NICU). During 6 months (from January 2001 to June 2001), 37 MRSA strains were isolated from 37 neonates who were admitted in the NICU and 52 MRSA were strains isolated from NICU environments. We performed DNA typing of MRSA using an arbitrary primed-PCR method on these isolates. Thirty-seven clinical isolates were classified into four types (A type, 14; B type, 4; C type, 4; D type, 3; and others, 12). The A-type strains of MRSA continued to be isolated for more than 6 months. In the NICU environment, the detection rate of the A-type MRSA was 23.1% (12/52). The A-type strains were frequently isolated from environments around patients. The A-type strains of MRSA were prevalent in the NICU, probably due to nosocomial infection. Although none of the neonatal patients developed severe MRSA infection, the same genotype strains were persistently isolated during a period of more than 6 months from patients and the NICU environment around patients. Environmental control around neonatal patients is important to prevent nosocomial infection in the NICU.