Maria Rosa Anna Plano

Outbreak of Infection with Klebsiella pneumoniae Sequence Type 258 Producing Klebsiella pneumoniae Carbapenemase 3 in an Intensive Care Unit in Italy

Gram-negative pathogens producing carbapenemases represent an alarming clinical threat with serious effects on patient outcomes ([3][1], [7][2]). In 2001, Yigit et al. ([11][3]) reported a novel β-lactamase termed “ K lebsiella pneumoniae carbapenemase” (KPC-1) in North Carolina. KPC-producing

Ventilator-associated Pneumonia and MRSA ST398, Italy

To the Editor: Methicillin-resistant Staphylococcus aureus (MRSA) sequence type (ST)398 has become increasingly common in livestock, particularly pigs, in some countries in Europe, such as Spain and Germany (1). In Italy, prevalences as high as 14% and 21.6% in pig-breeding facilities and meat-processing sites, respectively, have been recently reported (1). Possible association of MRSA in animals with infection in humans has been investigated. One study showed a strong relationship between contact with pigs or calves and carriage by persons having direct contact with animals and families of persons who handle animals (2). Moreover, an MRSA prevalence >11.9% has been described by de Boer et al. (3) in meat, with 85% of isolates belonging to the ST398 lineage. MRSA ST398 has been described as a lineage with limited virulence and ability to spread between humans, but severe clinical manifestations, such as wound infections and endocarditis, have been recently attributed to this clone (1,4). Cases of nosocomial ventilator-associated pneumonia have also been reported in Germany (1). Moreover, an outbreak of infection with MRSA ST398 occurred in a surgical ward of a hospital in the Netherlands in 2007 (5). MRSA ST398 is an infrequent cause of human infections in Italy. No isolates belonged to this lineage in 2 studies of MRSA in Italy during 2006–2007 (6) or in hospitals during 1990–2007 (7). Only 1 invasive infection has been recently reported in a pig farm worker (8). We report a case of ventilator-associated pneumonia caused by MRSA ST398 in a patient in Palermo, Italy. The patient and his household members did not report any exposure to companion or livestock animals. The case-patient was a 78-year-old man admitted to a cardiac intensive care unit (ICU) of ARNAS Ospedale Civico Di Cristina e Benfratelli in Palermo on January 31, 2009, because of a recent history of unstable angina pectoris and acute anemia caused by duodenal ulcers. After cardiocirculatory arrest, he was transferred to a general ICU on February 3. The patient had type 2 diabetes and ischemic-hypertensive cardiomyopathy. MRSA nasal colonization at admission was not investigated because the patient lacked risk factors for screening at admission, e.g., antimicrobial drug therapy, hospitalization for >48 hours or time in a long-term care facility within the past 6 months, need for long-term nursing care, presence of indwelling devices, or chronic skin lesions. The clinical course of the patient’s illness was characterized by serious hemodynamic instability and difficulty in weaning from mechanical ventilation. Two bronchial aspirate specimens were cultured on February 4 and 9, when he was being treated with a third-generation cephalosporin (ceftriaxone). These cultures showed Staphylococcus epidermidis and S. saprophyticus. On the 14th day in the ICU, clinical signs of ventilator-associated pneumonia developed in the patient. He had increased sputum production, fever (38.8°C), leukocytosis, and infiltrates were seen on a chest radiograph. Empiric antimicrobial drug therapy with glycopeptides and a β-lactam/β-lactamase inhibitor combination was started. Culture of bronchial secretions yielded MRSA that was susceptible to glycopeptides, rifampin, linezolid, macrolides, and sulfamethoxazole and resistant to fluoroquinolones and tetracyclines. Three days later, linezolid was given, but the patient died after an acute myocardial infarction. The isolate was identified genetically by mecA PCR. It was not typeable by pulsed-field gel electrophoresis after digestion with SmaI, negative for Panton-Valentine leukocidin, and carried staphylococcal cassette chromosome mec (SCCmec) type IVa (9). Multilocus sequence typing, performed according to a recommended procedure (http://saureus.mlst.net/misc/info.asp), identified the isolate as ST398. A 1-year epidemiologic survey on MRSA isolates from 4 general hospitals in Palermo, which had begun on February 2009, did not identify any MRSA isolate carrying SCCmec type IV or V in patients admitted to the ICU until September 2009. However, colonization or infection by MRSA ST398 in the ICU patients before the study period could not be ruled out. Although an MRSA screening policy for the ICU staff members was not being carried out, a nosocomial chain of transmission appeared to be unlikely. Our results indicate that a new zoonotic clone of MRSA is emerging as a potential cause of serious human infections. Screening at hospital admission would likely help efforts to determine whether exposure to pet animals and livestock had occurred. However, the absence of specific exposure to zoonotic clonal lineages, as in our case-patient, is a matter of concern in terms of screening and contact tracing policy for MRSA infections. Prevalence of MRSA and distribution of MRSA sequence types in livestock in Italy are not known. However, surveys of foods of animal (pig) origin have showed an MRSA prevalence of 3.7% (1,10). In view of the low prevalence of MRSA ST398 in patients with no exposure to animals, food products currently seem to play a negligible role. However, this clone is likely spreading because of the large animal reservoir of ST398 and the global market for meat and livestock. The changing epidemiology of MRSA indicates that collaborative surveillance plans integrating human and animal information should be increased.

Characterization of the First Extended-Spectrum β-Lactamase–Producing Nontyphoidal Salmonella Strains Isolated in Tehran, Iran

The infections caused by Salmonella remain a significant public health problem throughout the world. beta-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 beta-lactamases (ESBLs) in Salmonella spp. is a newly emerging threat worldwide. This study was carried out to characterize beta-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 bla(CTX-M-15) gene. Moreover, three of four strains that proved to be positive for a bla(TEM) gene were producing a TEM-1 beta-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

AbstractAim:We describe a one-year investigation of colonization by imipenem-resistant, 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:Twenty-two 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 MBL-producing 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.

Children, parents and Respiratory Syncytial Virus in Palermo, Italy: prevention is primary

A study was conducted to describe the characteristics of the Respiratory Syncytial Virus (RSV) infection cases occurring in the season 2006—7 in Palermo, Italy, and to evaluate the parents’ knowledge and behaviours concerning prevention and control of acute respiratory infections (ARIs). All children aged between 0 and 2 years, admitted for a lower respiratory tract infection (LRTI) between October 2006 and May 2007, were enrolled in the study. Data were collected about demographic and household characteristics. Furthermore, their parents were asked to compile a structured questionnaire on transmission, prevention and management of ARIs in children. A total of 198 children with a diagnosis of LRTI were enrolled. Ninety-eight (62.0%) of 157 were positive for RSV. Parents were generally aware of transmission of ARIs through sneezing and/or coughing, but less through contaminated objects or hands. Nationality, age and education level of parents and also the age of the patients proved to be associated with some self-reported knowledge and behaviours. Only 24 (12.3%) of the 195 respondents had received advice from GPs or paediatricians about good hygiene practices. It seems essential to implement public health interventions promoting behavioural changes aimed at the primary prevention of ARIs at the community level.

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

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.

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.