High incidence of antimicrobial resistant organisms including extended spectrum beta-lactamase producing Enterobacteriaceae and methicillin-resistant Staphylococcus aureus in nasopharyngeal and blood isolates of HIV-infected children from Cape Town, South Africa

BMC Infect Dis. 2008 Apr 1;8:40. doi: 10.1186/1471-2334-8-40.

Abstract

Background: There is little information on nasopharyngeal (NP) flora or bacteremia in HIV-infected children. Our aim was to describe the organisms and antimicrobial resistance patterns in children enrolled in a prospective study comparing daily and three times weekly trimethoprim-sulfamethoxazole (TMP-SMX) and isoniazid (INH) or placebo prophylaxis.

Methods: NP swabs were taken at baseline from HIV-infected children enrolled in the study. Standard microbiological techniques were used. Children were grouped according to previous or current exposure to TMP-SMX and whether enrolled to the study during a period of hospitalization. Blood culture results were also recorded within 12 months of baseline.

Results: Two hundred and three children, median age 1.8 (Interquartile [IQ]: 0.7-4) years had NP swabs submitted for culture. One hundred and eighty-four (90.7%) had either stage B or C HIV disease. One hundred and forty-one (69.8%) were receiving TMP-SMX and 19 (9.4%) were on antiretroviral therapy. The majority, 168 (82%) had a history of hospitalization and 91 (44.8%) were enrolled during a period of hospitalization. Thirty-two subjects (16.2%) died within 12 months of study entry. One hundred and eighty-one potential pathogens were found in 167 children. The most commonly isolated organisms were Streptococcus pneumoniae (48: 22.2%), Gram-negative respiratory organisms (Haemophilus influenzae and Moraxella catarrhalis) (47: 21.8%), Staphylococcus aureus (44: 20.4%), Enterobacteriaceae 32 (14.8%) and Pseudomonas 5 (2.3%). Resistance to TMP-SMX occurred in > 80% of pathogens except for M. catarrhalis (2: 18.2% of tested organisms). TMP-SMX resistance tended to be higher in those receiving it at baseline (p = 0.065). Carriage of Methicillin resistant S. aureus (MRSA) was significantly associated with being on TMP-SMX at baseline (p = 0.002). Minimal inhibitory concentrations (MIC) to penicillin were determined for 18 S. pneumoniae isolates: 7 (38.9%) were fully sensitive (MIC <or= 0.06 microg/ml), 9 (50%) had intermediate resistance (MIC 0.12 - 1 microg/ml) and 2 (11.1%) had high level resistance (MIC >or=2 microg/ml). Fifty percent of Enterobacteriaceae produced extended spectrum beta-lactamases (ESBL) (resistant to third generation cephalosporins) and 56% were resistant to gentamicin. Seventy-seven percent of S. aureus were MRSA. Carriage of resistant organisms was not associated with hospitalization.On multivariate logistic regression, risk factors for colonization with Enterobacteriaceae were age <or= one year (Odds ratio 4.4; 95% Confidence Interval 1.9-10.9; p = 0.0008) and CDC stage C disease (Odds ratio 3.6; 95% Confidence Interval 1.5-8.6; p = 0.005)Nineteen (9.4%) subjects had 23 episodes of bacteremia. Enterobacteriaceae were most commonly isolated (13 of 25 isolates), of which 6 (46%) produced ESBL and were resistant to gentamicin.

Conclusion: HIV-infected children are colonized with potential pathogens, most of which are resistant to commonly used antibiotics. TMP-SMX resistance is extremely common. Antibiotic resistance is widespread in colonizing organisms and those causing invasive disease. Antibiotic recommendations should take cognizance of resistance patterns. Antibiotics appropriate for ESBL-producing Enterobacteriaceae and MRSA should be used for severely ill HIV-infected children in our region. Further study of antibiotic resistance patterns in HIV-infected children from other areas is needed.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anti-Infective Agents / administration & dosage
  • Bacteremia / epidemiology
  • Bacteremia / microbiology*
  • Carrier State / epidemiology
  • Carrier State / microbiology
  • Child
  • Child, Preschool
  • Drug Resistance, Bacterial*
  • Enterobacteriaceae / drug effects
  • Enterobacteriaceae / enzymology
  • Enterobacteriaceae / isolation & purification
  • Enterobacteriaceae Infections / epidemiology
  • Enterobacteriaceae Infections / microbiology*
  • Female
  • HIV Infections / complications*
  • Humans
  • Incidence
  • Infant
  • Isoniazid / administration & dosage
  • Logistic Models
  • Male
  • Methicillin Resistance
  • Nasopharynx / microbiology*
  • Prospective Studies
  • Risk Factors
  • South Africa / epidemiology
  • Staphylococcal Infections / epidemiology
  • Staphylococcal Infections / microbiology*
  • Staphylococcus aureus / drug effects
  • Staphylococcus aureus / isolation & purification
  • Trimethoprim, Sulfamethoxazole Drug Combination / administration & dosage
  • beta-Lactam Resistance
  • beta-Lactamases / biosynthesis

Substances

  • Anti-Infective Agents
  • Trimethoprim, Sulfamethoxazole Drug Combination
  • beta-Lactamases
  • Isoniazid