Actualización en las resistencias de las bacterias grampositivas

Impact of changes in antibiotic prophylaxis on postoperative endophthalmitis in a Spanish hospital

OBJECTIVE

This study aims to assess whether changes in antibiotic prophylaxis used in cataract surgery in the La Mancha Centro General Hospital, Spain, were associated with a reduced incidence of postoperative endophthalmitis (POE).

METHODS

The hospital employed two different antibiotic prophylaxis regimens during two clearly differentiated periods. In the first period (January 2000 to April 2003), subconjunctival injections of gentamicin were used while in the second (May 2003 to December 2008), vancomycin and gentamicin were added to the irrigating solution. During both periods, povidone iodine was used at the site of surgery and aminoglycoside eye drops were administered postoperatively. A Poisson regression model was used to evaluate the relationship between the incidence rate of endophthalmitis and variables such as time trends, seasonality, and change in antibiotic prophylaxis regimen.

RESULTS

During the period between 2000 and 2008, 26 cases of POE were detected after 14,285 operations for an incidence rate (IR) of 1.8 cases per 1000 procedures (95% confidence interval 1.2-2.7 cases out of 1000 procedures). In the period prior to the change in prophylaxis, 23 cases were detected (IR 4.5 cases/1000 procedures) while only three cases were observed in the period after the change (IR 0.3 cases/1000 procedures). A total of 84% of the microorganisms isolated were gram-positive, and all were sensitive to vancomycin.

CONCLUSIONS

The change in antibiotic prophylaxis regimen for cataract surgery was associated with a relevant and significant decrease in the incidence of POE.

Molecular epidemiology of coagulase-negative Staphylococcus carriage in neonates admitted to an intensive care unit in Brazil

Background

Nasal colonization with coagulase-negative Staphylococcus (CoNS) has been described as a risk factor for subsequent systemic infection. In this study, we evaluated the genetic profile of CoNS isolates colonizing the nares of children admitted to a neonatal intensive care unit (NICU).

Methods

We assessed CoNS carriage at admittance and discharge among newborns admitted to a NICU from July 2007 through May 2008 in one of the major municipalities of Brazil. Isolates were screened on mannitol salt agar and tryptic soy broth and tested for susceptibility to antimicrobials using the disc diffusion method. Polymerase chain reaction (PCR) was used to determine the species, the presence of the mecA gene, and to perform SCCmec typing. S. epidermidis and S. haemolyticus isolated from the same child at both admission and discharge were characterized by PFGE.

Results

Among 429 neonates admitted to the NICU, 392 (91.4%) had nasal swabs collected at both admission and discharge. The incidence of CoNS during the hospitalization period was 55.9% (95% confidence interval [CI]: 50.9-60.7). The most frequently isolated species were S. haemolyticus (38.3%) and S.epidermidis (38.0%). Multidrug resistance (MDR) was detected in 2.2% and 29.9% of the CoNS isolates, respectively at admittance and discharge (p = 0.053). The mecA gene was more prevalent among strains isolated at discharge (83.6%) than those isolated at admission (60%); overall, SCCmec type I was isolated most frequently. The length of hospitalization was associated with colonization by MDR isolates (p < 0.005). Great genetic diversity was observed among S. epidermidis and S. haemolyticus.

Conclusions

NICU represents an environment of risk for colonization by MDR CoNS. Neonates admitted to the NICU can become a reservoir of CoNS strains with the potential to spread MDR strains into the community.

Ceftaroline in complicated skin and skin-structure infections

Ceftaroline is an advanced-generation cephalosporin antibiotic recently approved by the US Food and Drug Administration for the treatment of complicated skin and skin-structure infections (cSSSIs). This intravenous broad-spectrum antibiotic exerts potent bactericidal activity by inhibiting bacterial cell wall synthesis. A high affinity for the penicillin-binding protein 2a (PBP2a) of methicillin-resistant Staphylococcus aureus (MRSA) makes the drug especially beneficial to patients with MRSA cSSSIs. Ceftaroline has proved in multiple well-conducted clinical trials to have an excellent safety and efficacy profile. In adjusted doses it is also recommended for patients with renal or hepatic impairment. Furthermore, the clinical effectiveness and high cure rate demonstrated by ceftaroline in cSSSIs, including those caused by MRSA and other multidrug-resistant strains, warrants its consideration as a first-line treatment option for cSSSIs. This article reviews ceftaroline and its pharmacology, efficacy, and safety data to further elucidate its role in the treatment of cSSSIs.