Antibiotic-Resistant Gram Negative Bacilli in Meals Delivered at a General Hospital, Italy

This study aimed at detecting the presence of antibiotic-resistant Gram-negatives in samples of meals delivered at the University General Hospital of Palermo, Italy. Antibiotic resistant Gram negatives were isolated in July—September 2007 ffrom cold dishes and food contact surfaces and utensils. Bacterial strains were submitted to susceptibility test and subtyped by random amplification of polymorphic DNA (RAPD). Forty-six of 55 (83.6%) food samples and 14 of 17 (82.3%) environmental swabs were culture positive for Gram negative bacilli resistant to at least one group of antibacterial drugs. A total of 134 antibiotic resistant strains, 51 fermenters and 83 non-fermenters, were recovered. Fermenters and non-fermenters showed frequencies as high as 97.8% of resistance to two or more groups of antibiotics and non fermenters were 28.9% resistant to more than three groups. Molecular typing detected 34 different profiles among the fermenters and 68 among the non-fermenters. Antibiotic resistance was very common among both fermenters and non-fermenters. However, the wide heterogeneity of RAPD patterns seems to support a prominent role of cross-contamination rather than a clonal expansion of a few resistant isolates. A contribution of commensal Gram negatives colonizing foods to a common bacterial resistance pool should not been overlooked

Characterization of the first extended-spectrum b-lactamase–producing nontyphoidal Salmonella strains Isolated in Tehran, Iran

The infections caused by Salmonella remain a significant public health problem throughout the world. b-Lactams and fluoroquinolones are generally used to treat invasive Salmonella infections, but emergence and spread of antibiotic-resistant strains are being increasingly notified in many countries. In particular, detection of extended spectrum b-lactamases (ESBLs) in Salmonella spp. is a newly emerging threat worldwide. This study was carried out to characterize b-lactamase–producing Salmonella strains identified in Tehran, Iran. Over the 2-year period from 2007 to 2008, 6 of 136 Salmonella isolates recovered from pediatrics patients, including three Salmonella enterica serotypes Enteritidis (S. Enteritidis) and three S. Infantis, showed an ESBL-positive phenotype. Polymerase chain reaction and sequencing were used to identify the genetic determinants responsible for ESBL phenotypes. The Salmonella isolates were also compared by pulsed-field gel electrophoresis. All ESBL-producing strains, but one, carried the blaCTX-M-15 gene. Moreover, three of four strains that proved to be positive for a blaTEM gene were producing a TEM-1 b-lactamase. Two strains of S. Infantis tested positive for a previously unidentified CTX-M and TEM ESBL, respectively. All ESBL-producing strains carried the insertion sequence ISEcp1 gene. Except for one strain of serotype Infantis, all strains were able to transfer the ESBL determinants by conjugation. Distinct, but closely related, pulsed-field gel electrophoresis patterns were observed among the strains belonging to both serotypes. This study reports for the first time the emergence and characterization of ESBL-producing S. Enteritidis and Infantis strains in Iran

Nosocomial colonization due to imipenem-resistant Pseudomonas aeruginosa epidemiologically linked to breast milk feeding in a neonatal intensive care unit.

Aim: We describe a one-year investigation of colonization by imipenemresistant, metallo-β-lactamase (MBL) producing Pseudomonas aeruginosa in a neonatal intensive care unit (NICU) of the University Hospital of Palermo, Italy. Methods: A prospective epidemiological investigation was conducted in the period 2003 January to 2004 January. Rectal swabs were collected twice a week from all neonates throughout their NICU stay. MBL production by imipenem-resistant strains of P aeruginosa was detected by phenotypic and molecular methods. Pulsed field gel electrophoresis (PFGE) was carried out on all isolates of P aeruginosa. The association between risk factors and colonization by imipenem-resistant, imipenem-susceptible P aeruginosa isolates and other multidrug-resistant Gram negative (MDRGN) organisms was analyzed for variables present at admission and during the NICU stay. Data analysis was carried out by the Cox proportional hazards regression model. Results: Twentytwo of 210 neonates were colonized with imipenem-resistant, MBL-producing P aeruginosa isolates and 14 by imipenem-susceptible P aeruginosa isolates. A single pulsotype, named A, was shared by all imipenem-resistant isolates. Colonization by P aeruginosa of pulsotype A was positively correlated with breast milk feeding and administration of ampicillin-sulbactam, and inversely correlated with exclusive feeding by formula. In the Cox proportional hazards regression model, birthweight of more than 2500 g and breast milk feeding were independently associated with an increased risk of colonization by MBLproducing P aeruginosa. Conclusion: The results strongly support an association between colonization by a well-defined imipenem-resistant, MBL producing P aeruginosa strain and breast milk feeding. Such a study may highlight the need for implementation of strategies to prevent expressed breast milk from becoming a vehicle of health care-associated infections

MRSA ST22-IVa (EMRSA-15 clone) in Palermo, Italy

Summary: Epidemic spread of methicillin-resistant Staphylococcus aureus (MRSA) strains carrying the Staphylococcal Chromosomal Cassettes (SCC) mec type IV is being increasingly reported in many geographical areas. A survey to determine the prevalence and characteristics of MRSA SCCmec IV isolates identified in four general hospitals in Palermo, Italy, was carried out. During the period February–June 2009, SCCmec type IVa has been found in 12 out of 94 isolates. Nine isolates from all hospitals and all strains from a NICU outbreak occurring in the same period were attributed with the ST22-IVa (EMRSA-15) clone. In our setting, due to the changing MRSA epidemiology, detection of SCCmec IV could be poorly predictive of CA-MRSA. Keywords: MRSA, ST22-IVA, EMRSA-15, Epidemiology, Molecular typin